Assessment Procedure and Criteria for Determining Suitability of Commercial Components for Space Use

Transcription

1 DLR-RF-PS-003 Issue 1.1 Sept Assessment Procedure and Criteria for Determining Suitability of Commercial Components for Space Use DLR Deutsches Zentrum für Luft- und Raumfahrt German Space Agency

2 DLR RF-PS-003 Issue 1.1 Sept 2008 Assessment Procedure and Criteria for Determining Suitability of Commercial Components for Space Use Prepared Approved Released J. Tetzlaff / QP-NB Standardization and EEE-Components DLR M. Scheuer-Leeser / QP-L Head of Product Assurance DLR C. Hohage / RD-J Director Space Projects DLR Date: Date: Date:

3 Document Change Record Issue/Rev Date Change Notice No. Modified Pages or Paragraphs 1.0 July Initial Issue Nature of Change 1.1 Sept Cover Sheet Added

4 DLR RF-PS-003 Issue 1.1 Sept Assessment Procedure and Criteria for Determining Suitability of Commercial Components for Space Use TESAT-Spacecom GmbH & Astrium GmbH Prepared under DLR Contract No. 50 PS 0010 PHASE D, WORK PACKAGE 1 DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

5 CONTENTS 1 INTRODUCTION Scope Assessment Approach Document Layout Definitions and Abbreviations References 6 2 ASSESSMENT GUIDE Key Elements Assessment Flow Assessment Procedure Risk Control 11 3 SUBSTITUTES FOR MISSING INFORMATION Introduction Information from Other Sources Additional Testing/Inspection Detailed Guide for each Key Element Thermal Performance Characteristic Mechanical Performance Characteristic Constructional Performance Characteristic Radiation Process Control Reliability Assessment System Reliability Data Final Production Electrical Measurements Average Outgoing Quality Quality System Traceability Specification Delivery Time 15 4 DETAILED ASSESSMENT INFORMATION Key Element Importance and Assessment Detailed Assessment Criteria for Key Elements Thermal Performance Characteristic Mechanical Performance Characteristic Constructional Performance Characteristic Radiation Process Control Reliability Assessment System Reliability Data Final Production Electrical Measurements Average Outgoing Quality Quality System Traceability Specification Delivery Time 52 DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

6 5 BACKGROUND INFORMATION Use of Commercial Components in Space Equivalence of Commercial and Space Qualified Parts 54 APPENDIX 1 FORM SHEETS 55 DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

7 1 INTRODUCTION 1.1 Scope This document describes a simple, effective and standardised procedure for assessing whether commercially available components meet the performance requirements for space applications. The approach adopted is straightforward so that users can apply it without needing an in-depth knowledge of any technical aspects of the part under assessment. It is also flexible enough to be used for commercial components fabricated using widely different processes, employing many different structures, and manufactured by companies having different quality systems, methods and standards. 1.2 Assessment Approach The basic assessment approach relies on the assessment of individual key elements which have been identified as both sufficient and essential for the overall acceptability of a component. The "key" elements are parameters that quantify the quality and reliability of the component, the manufacturer of the component and its availability for use in space programmes. A component assessed using this procedure can be individually assessed as: Acceptable for general space use. (all key elements are acceptable) Acceptable for use on a specific project. (one or more key elements are only acceptable for specific project use) Unacceptable. (one or more key elements are unacceptable) A detailed description of the key elements for assessment is given in chapter 4 of this document. The assessment procedure and criteria for individual key elements are designed to make the maximum possible use of existing information, although appropriate methods for generating any missing information are also covered. If a key element cannot be assessed directly, then it may be possible to give an assessment on the basis of supporting information. For example, if no reliability data is available, it may be possible to make an assessment on the basis of reliability data for a similar component from the same manufacturer. In this document, the indirect assessment of a key element is called assessment using "alternative information". The basic assessment approach described in this document is extended in a supplementary document entitled Risk Analysis and Management. If appropriate risk analysis and management actions are carried out the extended approach can allow components to be accepted for specific project use even if not all the key element criteria are satisfied. 1.3 Document Layout The remainder of this document comprises five sections which contain: A step by step guide to the assessment procedure, including an illustrative flow chart. An additional guide covering the possibility of completing a key element assessment by using alternative information obtained from other sources. This can be applicable if some of the information normally required to complete the assessment is not available. A detailed description of each key element and the appropriate acceptance criteria. This should be consulted during an assessment to ensure consistent and standard results. Background information about the reasons for using commercial components in space applications, and the justification for considering some commercial components to be of equivalent quality to traditional space qualified components. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

8 An appendix containing a set of suitable form sheets which can be used for documenting a component assessment. 1.4 Definitions and Abbreviations The following definitions and abbreviations are used in this document. AOQL Average outgoing quality level CVCM Collected volatile condensable material DDEF Displacement damage equivalent fluence DEC Dynamic evaluation circuit DOE Design of experiments ESD Electrostatic discharge FET Field effect transistor FIT Failure in time FMECA Failure modes, effects and criticality analysis PCM Process control monitor PIND Particle impact noise detection QA Quality assurance RF Radio frequency RML Recovered mass loss RVT Radiation verification testing SEBO Single event burn-out SEE Single event effect SEGR Single event gate rupture SEL Single event latch-up SEU Single event upset SEM Scanning electron microscope SMD Surface mount device SPC Statistical process control TCV Technology control vehicle TID Total ionising dose TML Total mass loss WLR Wafer level reliability DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

9 1.5 References AQAP-110 NATO Quality Assurance Requirements for Design, Development and Production ASTM-E Outgassing EIA/JESD-46-A Guidelines for User Notification of Product/Process Changes by Semiconductor Suppliers EIA/JESD-47 Stress-Test-Driven Qualification of Integrated Circuits EIA/JESD-48 Product Discontinuance EIA/JEP-122 Failure Mechanisms and Models for Silicon Semiconductor Devices EIA/JEP-131 Process Failure Mode and Effects Analysis (FMEA) EIA/JEP-132 Process Characterisation Guidelines EIA-554-A Method Selection for Assessment of Non-conforming Levels in Parts-Per- Million (PPM) EIA Assessment of Average Outgoing Quality Levels in Parts-Per-Million (PPM) EIA Assessment of Non-conforming Levels in Parts-Per-Million (PPM) EIA-557-A Statistical Process Control Systems EIA-591 Assessment of Quality Levels in PPM using Variables Test Data EIA-659 Failure-Mechanism-Driven Reliability Monitoring EIA-738 Guideline of the Use and Application of Cpk ESA/SCC22900 Total Dose Steady State Irradiation Test Method ESA/SCC25100 Single Event Effects Test Method and Guidelines ECSS-Q-70-02A Thermal vacuum outgassing test for the screening of space materials JEDS-16A Assessment of Average Outgoing Quality Levels in Parts-Per-Million (PPM) JESD-34 Failure-Mechanism-Driven Reliability Qualification of Silicon Devices MIL-STD-202 Test Methods for Electronic and Electrical Component Parts MIL-STD-750 Test Methods for Semiconductor Devices MIL-STD-883 Test Method Standard Microcircuits MIL-PRF Performance Specification Semiconductor Devices, General Specification for MIL-PRF Performance Specification Hybrid Microcircuits, General Specification for MIL-PRF Performance Specification Integrated Circuits (Microcircuits) Manufacturing, General Specification for MIL-HDBK-683 Statistical Process Control (SPC) Implementation MIL-HDBK-814 Ionising Dose and Neutron Hardness Assurance Guidelines QS9000 Quality Systems Requirements ESA PSS Failure Rates for ESA Space Systems DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

10 2 ASSESSMENT GUIDE 2.1 Key Elements As explained in Paragraph 1.2 this procedure relies on the assessment of key elements in order to make an overall assessment of the component type acceptability for space applications. The chart below shows those key elements which were identified, during the development of this procedure, as being necessary and sufficient for assessing a component. To permit an easier understanding of their significance they are grouped under the headings of Parts Related, Manufacturer Related and Procurement Related, which are also often used in describing Project PA requirements for components. ASSESSMENT Parts Related Manufacturer Related Procurement Related Performance characteristics Quality assurance system Specification Thermal Quality system Specification Mechanical Constructional Radiation Dependability Customer Support Availability Process control Reliability assessment system Reliability data Traceability Delivery time Final production electrical measurements Average outgoing quality Figure 1 Key assessment elements grouped into three general categories DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

11 2.2 Assessment Flow The following flowchart depicts graphically the basic approach to be used when assessing commercial components for space applications. Define sequence of assessment of the key elements *) KEY ELEMENT X KEY ELEMENT 2 KEY ELEMENT 1 Additional Screening (Risk control) **) Additional screening required Direct assessment of key element Insufficient data Indirect assessment of key element ***) Element acceptable Acceptable for specific projects with risk Accept for specific projects Element unacceptable Risk Analysis Key element generally acceptable Key element acceptable for specific project requirements Key element not acceptable All key elements acceptable one or more key elements are only acceptable for specific project use One or more key elements unacceptable Component acceptable for general space use Component acceptable for use on a specific project Component unacceptable *) The sequence of assessment shall be defined such that unacceptable key elements are found as early as possible in order to minimise the overall effort. **) The assessment result is only valid for procurement with the applied screening measures ***) Assessment on the basis of alternative data. Can also include additional testing. Figure 2 Basic assessment flow DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

12 If it decided to perform a risk analysis exercise this is covered by a separate procedure included in the document entitled Risk Analysis and Management. A decision to perform a risk analysis for a key element can allow the component assessment to continue either: - After satisfactory completion of the risk analysis. - Immediately, in order to allow any other key elements requiring risk analysis to be identified. The necessary risk analyses can then all be performed together at the completion of the assessment. Performing an optional risk analysis exercise can allow a component to be accepted for specific project use (possibly with the requirement that appropriate risk control measures are adopted) even though not all the key element acceptance criteria are met. 2.3 Assessment Procedure In this section a simple step by step guide to completing a basic component assessment is given. While performing an assessment it will frequently be necessary to refer to Section 4 of this document as it contains a detailed description of each key element and the appropriate acceptance criteria. It will therefore be useful to read Section 4 before starting an assessment in order to become familiar with its contents and to understand what types of information need to be available to perform an assessment. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

13 Step 1. Identify component to be assessed The assessor should have a clear knowledge and understanding of exactly which component is to be assessed in terms of manufacturer, generic type, variant/option/revision, qualification/test level, etc. Step 2. Obtain relevant information All readily available published information relevant to the component to be assessed should be obtained. This will generally be manufacturer s information and information from other sources in the public domain, but might also include proprietary information which has been made available to the assessor. The detailed criteria in Section 4 of this document show the areas which the information must cover. Step 3. Prepare assessment result forms To record the results of the assessment a suitable set of forms in printed or electronic format should be used. The Appendix to this document includes a set of forms suitable for this purpose. They should initially be prepared by completing all the necessary information to identify the exact component type which is being assessed ASSESSMENT OF KEY ELEMENTS Step 4. Select a key element to be assessed A key element which has not yet been assessed should be selected from those identified in Section 2.1 and on the form. It is not necessary to assess the key elements in the sequence used in this document and any order can be adopted. To reduce the overall effort required assessors might prefer to start the assessment with those key elements for which a result of not acceptable is considered most likely. Step 5. Assessment of the selected key element Assessment of the selected key element should be started to the criteria given in section 4 of this document. It should be identified at this stage whether all the necessary information to complete the assessment and reach a conclusion is available. If a direct assessment is possible go to step 7. Repeat for each key element Step 6. Decide whether additional information can be obtained A decision should be based on whether it is at all possible that alternative, equivalent or related information could be a suitable substitute for the missing information, and whether the effort necessary to generate or obtain such information is considered justifiable. Section 3 of this document should be used as an aid to making this decision. If the decision is negative go to step 7. Additional information can be either already existing information which is obtained from alternative sources, or new information which is generated by the assessor, e.g. by procuring and testing sample components or by auditing the manufacturer. Step 7. Decide whether the key element is acceptable A decision as to whether the key element is acceptable should be based on all the available information (including additional information if applicable) and should be made using the criteria given in Section 4 of this document. Step 8. Decide whether risk analysis and management are appropriate If a key element is assessed as not acceptable, either because it clearly does not meet the criteria or because insufficient information is available to verify that it meets the criteria, then risk analysis and management might be appropriate. Risk analysis and management are not covered in this document but are described in a supplementary document entitled Risk Analysis and Management. The result of a risk analysis and management exercise could be that a component is considered potentially acceptable for specific use despite having a key element which is assessed as not acceptable to the defined criteria. Step 9. Decide on acceptability of component For a basic assessment the result for the component is determined on the basis of the key element results. It is equal to the worst result obtained for any of the individual key elements and the possible component assessment results are therefore: If a risk analysis and management exercise is performed in accordance with the supplementary document then it is possible to accept a component for specific project use even if a key element is assessed as not acceptable. There is also an additional Step 10. Complete assessment forms The assessment forms for the component which has been assessed should be completed giving all the relevant results and references to the sources of information used to justify the conclusions. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

14 2.4 Risk Control This assessment procedure allows measures for risk reduction to be applied in order to give increased confidence in the quality and reliability of the component. Allowing risk control measures (Including screening) will increase the number of commercial part types assessed as usable for space applications. Similar risk reduction measures as those often applied to the procurement of space qualified components can also be applied to commercial components in order to increase confidence in the quality and reliability of the flight parts. Such measures are generally not applied to commercial components for terrestrial applications where a strategy of "built-in" quality and reliability without additional screening has been established. However, for space applications, with relatively low quantities of parts, risk reduction measures can be usefully applied to both commercial and space qualified parts. These additional risk reduction measures are not intended to be implemented on all part types as is the case for space qualified parts. As for some commercial applications, they are intended to eliminate specific weaknesses of the components. Typical risk control measures are: - Burn-in - Inspections (visual, X-ray, SEM...) - Selection on the basis of electrical measurements - Other screening measures (E.g. PIND testing of cavity parts, vibration & shock testing - Radiation verification tests - Destructive Physical Analysis Some of these measures are applied to the parts to be used in flight application and some are applied to sample quantities of the available parts and may or may not be destructive. If the inclusion of risk reduction measures has been used for the assessment of a component then it is important that those measures are clearly identified. The result of the assessment is only valid for parts procured and verified using the proposed measures for risk reduction. Any risk reduction measures have to clearly define the conditions that have to be satisfied for acceptance. The assessment of each key element may identify measures for risk reduction that need to be applied in order to achieve sufficient confidence for a positive assessment of that key element. The risk reduction measures must be registered in the assessment summary sheet given in Appendix 1 of this document. The assessor must decide if possible risk control measures are reasonable and acceptable for a space parts procurement. If not, the key element is not acceptable and hence the component is unacceptable for space use. In addition to this document for assessment of commercial components, an additional supporting document entitled "Risk Analysis and Control" has also been prepared. That document is designed to be support the assessment of components that have been found to be only acceptable for specific project requirements. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

15 3 SUBSTITUTES FOR MISSING INFORMATION 3.1 Introduction If a key element assessment cannot be completed because essential data or information are missing, it is possible with some elements to obtain suitable information from other sources or to generate it by performing additional tests or inspections. Component information obtained in these ways need not necessarily be identical to the data originally required, but could be alternative/equivalent/related information which is nevertheless suitable for assessing the acceptability of the key element or performing risk analysis on the component Information from Other Sources If the information necessary for directly assessing the acceptability of a key element is not obtainable directly from the manufacturer then generally the only other source will be a major customer who procures large quantities of the component. Such a customer might have been able to exert sufficient pressure on the manufacturer to extract additional information, or might have performed their own testing to generate the additional information. However, even if a customer is identified who possesses the necessary information it might not be possible to obtain it because the manufacturer and/or customer might have defined it as proprietary. If a customer has generated information by performing their own testing or inspection then this could cover any of the key element assessment areas described in the following paragraph For a major customer it could also include an AOQL figure generated by checking all the received components to determine how many defective parts are supplied by the manufacturer. If a major customer has used their larger purchasing power to apply pressure on the manufacturer to supply additional information then this information could cover any of the areas included in the assessment procedure. If additional information is obtained for use in risk analysis, rather than for use in directly assessing a key element, the range of potentially relevant information and possible sources is much wider and cannot be defined here in detail Additional Testing/Inspection If the necessary financial and manpower resources are available to procure and test special test samples as part of an assessment exercise then this is an option which should always be carefully considered to generate information which cannot be obtained from the manufacturer. The following table gives the key elements and assessment areas for which additional testing is a realistic option for generating missing information. For other key elements it is not possible to replace any missing information with sample test results because acceptance of the element requires long term test results or requires the manufacturer to have specific systems installed. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

16 Key Element Assessment Area Suggested Test Method Mechanical performance characteristic (Paragraph 3.2.2) Constructional performance characteristic Vibration and shock testing Design, materials and workmanship Relevant test methods in Mil-Std-202, Mil-Std-750 and Mil-Std-883 Constructional analysis to an established space level procedure (Paragraph 3.2.3) Outgassing ECSS-Q-70-02A or ASTM-E Radiation (Paragraph 3.2.4) Total ionising dose and single event effects ESA/SCC 22900, ESA/SCC or Mil-Std-883 methods 1019, 1020, 1021, 1022, Detailed Guide for each Key Element Note that to maintain correspondence between the paragraph numbers in this section and in Section 4.2 all the key elements are included below. Those for which obtaining additional information is not considered a realistic option are included in italics Thermal Performance Characteristic If insufficient information is available from the manufacturer to determine the true operating and storage temperature ranges then generating the necessary information is not considered a realistic option. This is because of the extensive testing which would be necessary to determine with sufficient confidence the true range over which the parts could be operated/stored without compromising their reliability Mechanical Performance Characteristic If insufficient information is available from the manufacturer to confirm the component s shock and vibration capabilities then generating the necessary information is considered a realistic option. This is because the mechanical performance of a component is design related and could be expected to be similar for all components of the same type. The necessary information could therefore be generated by relatively simple shock and vibration testing of a limited number of specifically procured test samples Constructional Performance Characteristic If insufficient information is available from the manufacturer to confirm the component s constructional performance then generating the necessary information is considered a realistic option. This is because it would be possible to check the design, workmanship, outgassing, and use of prohibited materials or constructions by inspection/test of a limited number of specifically procured test samples Radiation If insufficient information is available from the manufacturer to confirm the component s radiation performance then generating the necessary information is considered a realistic option. As it is anticipated that radiation data will be unavailable for most commercial components the necessary testing for generating suitable data is already described in this assessment procedure document. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

17 3.2.5 Process Control If insufficient information is available from the manufacturer to confirm that the applied process control is acceptable then generating alternative suitable information is not considered a realistic option. This is because assessment of this key element relies entirely on information which can only be provided by the manufacturer Reliability Assessment System If insufficient information is available from the manufacturer to confirm that the reliability assessment system is acceptable then generating alternative suitable information is not considered a realistic option. This is because assessment of this key element relies entirely on information which can only be provided by the manufacturer Reliability Data If insufficient information is available from the manufacturer to determine the component reliability then generating the necessary information is not considered a realistic option. This is because of the extensive testing which would be necessary to determine with sufficient confidence the reliability of the parts Final Production Electrical Measurements If insufficient information is available from the manufacturer to demonstrate that all critical electrical parameters are measured on 100% of parts before shipping then it is not possible to demonstrate this using information from any other source. This is because only information from the manufacturer can confirm exactly what in-house final testing is performed on the delivered components. The possibility of accepting such components on the basis that all procured parts are electrically tested after receipt is covered in the supplementary risk analysis and management document Average Outgoing Quality If insufficient information is available from the manufacturer to determine the average outgoing quality level then obtaining the necessary information from another source might be a realistic option. If the identical part was supplied to a commercial customer in million high quantities then such a customer might have available suitable information on the risk of a defective part being delivered. For anyone else to perform testing to determine the AOQL would not be a realistic option because of the extremely high number of components which would need to be tested Quality System If insufficient information is available from the manufacturer to determine whether the quality system used is acceptable then obtaining suitable information from another source is not considered a realistic option. It is assumed that if another customer with similar requirements had already audited the manufacturer s QA system and found it to be satisfactory then the manufacturer would inform other potential customers of this Traceability If insufficient information is available from the manufacturer to determine whether the level of traceability is acceptable then obtaining suitable information from another source is not considered a realistic option Specification If there is insufficient information available from the manufacturer then this will always fail the criteria for available documentation to form an acceptable specification. Generating additional information is therefore not considered a realistic option. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

18 Delivery Time If there is insufficient information available from the manufacturer to confirm an acceptable delivery time then this is always unacceptable. Obtaining alternative information is therefore not considered a realistic option. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

19 4 DETAILED ASSESSMENT INFORMATION 4.1 Key Element Importance and Assessment The following table lists the key elements which have been identified as necessary for performing a component assessment together with the reasons why it is important that the element should be found acceptable. Key Element Importance No Name PARTS RELATED Performance Characteristics 1 Thermal Thermal requirements must be satisfied to be certain that a part s electrical performance and failure rate will be as specified 2 Mechanical Mechanical requirements must be satisfied to be certain that a part will not fail due to mechanical stresses in typical space applications 3 Constructional Constructional requirements must be satisfied to be certain that a part does not use materials or processes which could cause failures 4 Radiation Radiation requirements must be satisfied to be certain that a part will not fail electrical function or parameter requirements in typical space applications Dependability 5 Process Control The level of process control must be sufficient to ensure good reproducibility and therefore parts with consistent performance 6 Reliability assessment system The reliability assessment system must be well designed in order to give confidence in the reliability data generated 7 Reliability data The indicated level of reliability must be sufficiently high for typical space applications 8 Final production electrical measurements Sufficient characterisation of each delivered component must be carried out to verify that the defined electrical performance and parameters are met 9 Average outgoing quality The quality level of the part must be good enough to ensure that the risk of receiving defective parts is sufficiently low to be acceptable for typical space applications MANUFACTURER RELATED Quality Assurance System 10 Quality system The quality management system must be good enough to ensure that control of all processes and procedures is sufficient to consistently produce components of adequate quality and reliability Customer Support 11 Traceability A minimum level of traceability must be assured, particularly for radiation sensitive components, to allow the identification of parts which potentially have lot related problems PROCUREMENT RELATED Specification 12 Specification A written specification, or equivalent, defining essential characteristics and important parameter limits must be available in order to specify exactly what is being procured Availability 13 Delivery time The delivery time of the component must be compatible with space project schedules Table 1 Key assessment elements DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

20 To assess a component each key element must be systematically assessed using the detailed criteria and guidance given in Section 4.2. For each key element a description of the element, a table containing the appropriate criteria for accepting the component for general or project specific use, and supporting information and guidance to help in the assessment are provided. In some cases additional supporting information and guidance is given which is only applicable to specific component families or technologies, but any limitations to applicability are always identified. At the completion of the element assessment a decision must be made as to whether it is acceptable for general use, acceptable for specific use, or not acceptable. The assessment result for the component is then equal to the worst result obtained for any of the individual key elements. The possible component assessment results are therefore: - acceptable for general use - acceptable for specific project use - not acceptable. As all of the key elements must be acceptable if the component is to be acceptable a component assessment should be terminated as soon as a single key element is found which is not acceptable. To extend the capabilities of this basic assessment procedure there are three areas where additional activities can be performed. These cover: (a) (b) (c) Insufficient information if insufficient information is available to verify that a key element meets the specified criteria then that element must normally be assessed as not acceptable, even if there is also insufficient information to definitely verify that it does not meet the criteria. For some key elements, however, it is possible to identify alternative, equivalent or related information which could be obtained from other sources or which could be generated by additional testing or inspection. This additional information might then allow the key element to be assessed as acceptable. It should be noted that only relatively limited additional testing or inspection is envisaged as forming part of an assessment covered by this document, and not anything as extensive as traditional space level evaluation or qualification testing. Obtaining alternative, equivalent or related information in place of missing information is covered in this document (Section 3). Risk analysis if a key element cannot be assessed as meeting the specified criteria, even if additional information is obtained and used, the component might still be acceptable if the information can be used to demonstrate an acceptable risk in a specific application. Risk analysis will not be applicable for all key elements and when performed might identify that the components can only be used if appropriate risk control actions (preventive or back-up solutions) are taken. Risk analysis and control are not covered in this document but are covered in a separate document entitled Risk Assessment and Control. Risk control if risk analysis shows that a component is not acceptable for use as is, it might still be possible to use it if appropriate risk control activities are defined and taken. Risk control activities can cover either preventive actions (to prevent a risk event from occurring) or back-up actions (to mitigate any unwanted effects if the risk event does occur). Risk control also covers the acceptance of commercial component types on the basis that 100% component screening, or sample lot acceptance testing, is performed on all procured parts. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

21 Risk control is not covered in this document but is covered in a separate document entitled Risk Analysis and Control. In Section 4.2 of this document it is indicated for each key element whether or not additional activities could be appropriate if it is not initially possible to assess the element as acceptable. This indication is given after the table in part B of the detailed criteria for each key element. If it is identified during a component assessment that any of these additional activities are appropriate for a key element then a number of options are available to the assessor. The two principal options would be to complete all applicable additional activities on each individual key element as the need is identified, or to complete the basic assessment on all the key elements and then perform all the additional activities together at the end. The following table also gives a quick overview of which additional activities can be applicable for each key element. Key Element Insufficient Information (assessment using supporting data) Risk Analysis Risk Control Thermal 4 Parts related (performance) Mechanical 4 Construction 4 Parts related (dependability) Radiation Process Control Reliability Assessment System Reliability Data Final Electrical Test 4 4 AOQL Manufacturer related Procurement related Quality System Traceability Specification Delivery Time DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

22 4.2 Detailed Assessment Criteria for Key Elements Thermal Performance Characteristic A. Description of Element The thermal performance is defined by two different temperature ranges, the operating temperature range and the storage temperature range. The operating temperature range is the range of temperature given in the data sheet or the procurement specification over which the manufacturer guarantees that the electrical performance of the component is within the specified limits. The storage temperature range is the range of temperature given in the data sheet or the procurement specification over which the manufacturer guarantees that the components can be non-operatively stored without degradation. Both temperature ranges are applicable to the external package or case temperature of the component. B. Assessment Assessment Criteria Operating temperature -25 C to +85 C, or better and Storage temperature -30 C to +85 C, or better Lower parts temperature of operation / storage is 5 C or more below lowest temperature of equipment operation / storage, and Upper parts temperature of operation is 20 C or more above the highest operation temperature of equipment, and Upper parts storage temperature is 10 C or more above highest storage temperature of equipment. Neither of the above conditions is satisfied or sufficient information for an assessment is not available Acceptable for general use Acceptable for specific project use Not acceptable Further analysis is not considered appropriate for this element. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

23 C. Supporting Information Extended temperature range The operation and storage temperature ranges for the components are usually given in the data sheet or in the procurement specification. If these temperature ranges do not cover the required temperature ranges for the application, either for general use of for specific use, then the component should not normally be accepted for space use. An exception can be made if the manufacturer has additional information which allows him to guarantee the performance over the extended temperature range. Temperature derating For space projects it is common practice that the operating temperature ranges at component level be derated by a specific factor. The derated operational and storage temperature ranges must not be exceeded during testing or during the mission. This derating is applied in order to give more confidence that the space equipment will survive the foreseen life period. The operational and storage temperature ranges of commercial component are normally smaller that those of traditional hi-rel space components. Full temperature derating cannot therefore be applied for most commercial component types because this would lead to derated temperature ranges that would not meet typical project needs. When considering the applicability of temperature derating for commercial components, it should be taken into consideration that commercial components are often manufactured using the identical technology to the equivalent space qualified components even though they have a lower temperature range specified. The real temperature capabilities of some commercial components might therefore be greater than is indicated by the published temperature range, and the manufacturer has therefore effectively already incorporated some derating into his published figures. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

24 4.2.2 Mechanical Performance Characteristic A. Description of Element The mechanical performance covers the ability of the component to withstand mechanical stresses during handling and transportation. This applies to the individual component, to the component after assembly into a unit of equipment, and during the launch of the equipment by the carrier vehicle. The normal mechanical stresses are vibration and shock. Commercial components for use in space applications must have demonstrated their ability to withstand these stresses. The values given below for general assessments are an average of different actual space programme requirements. B. Assessment Assessment Criteria The part is robust against Sine Vibration: Hz, 50 g, 2 min per axis and Shock: 5 shocks per direction, 1000 g or higher The values are within the limits specified for the specific space project Neither of the above conditions is satisfied or sufficient information for an assessment is not available Acceptable for general use Acceptable for specific project use Not acceptable Further analysis could be appropriate for this element if sufficient information is not initially available. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

25 C. Supporting Information Self-resonance of printed circuit boards used in space equipment The vibrational stresses experienced by components assembled onto printed circuit boards which have been integrated into space equipment might be higher than the levels given in the performance specification for the space equipment. This is due to self-resonance which can randomly occur at some specific locations on the boards. In some cases this amplified stress might be more than 10 times higher than the inducing stress at equipment level. This aspect has to be taken into consideration if the individual project requirements are to be used for the assessment. Assessment for specific space projects The vibrational stress at equipment level is usually of a random nature, whereas the vibration testing done at component level is normally of a sinusoidal nature. Therefore, the random vibration requirements at equipment level must be transformed into appropriate sinusoidal vibration requirements at component level. The self-resonance, as described above, which might occur at equipment level must be considered additionally. Testing method and mounting of the components The methods used for vibration testing and mechanical shock shall be equal to or similar to the relevant test methods described in the MIL standards MIL-STD-202, MIL-STD-750, or MIL-STD The device shall be rigidly fastened to the test platform and the leads or cables, if there are any, should be adequately secured. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

26 4.2.3 Constructional Performance Characteristic A. Description of Element A component with good constructional performance shall have a mature construction and design using materials with proven compatibility. The design has to be robust enough to withstand handling and to be easily assembled into the equipment without damage using well established assembly techniques. The components shall be made using a reproducible and stable production process and shall show good workmanship. Materials and component constructions which are known as critical for space applications, due to their nature or due to experience gained from previous space programmes, shall be avoided. B. Assessment Assessment Criteria The component shall cover the requirements stated in the supporting information in part C of this paragraph. The materials and construction are compliant with the specific space project requirements Neither of the above conditions is satisfied or sufficient information for an assessment is not available Acceptable for general use Acceptable for specific project use Not acceptable Further analysis could be appropriate for this element if sufficient information is not initially available. No specific limits are specified for the assessment described above. The assessor has to make a decision based on his experience and on the data available. Therefore, it is highly recommended that the person selected to carry out the assessment has been involved in the technical aspects of parts procurement, or previously involved in the production of the kind of component under consideration in order to have sufficient experience and skill to be able to make the assessment. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

27 C. Supporting Information Construction and design The design and construction of the component have to be mature and it shall be robust against handling and transportation stresses such as vibration, shock, ESD, etc. The individual parts of the component shall use appropriate materials, e.g. with good matching of the thermal coefficients of the lead material, package or case, insulation materials, die attachment material etc. They shall also be able to withstand the electrical, mechanical and thermal stresses which are expected in the application by having, e.g., adequate current density, field strength, thermal conductivity, etc. Ideally there should be evidence that after the component was designed the manufacturer processed at least one engineering lot and then subjected parts to constructional analysis to verify the integrity. Special design features in discrete semiconductors and integrated circuits, such as diffusion barriers in metal layer constructions and coatings, internal bond-wiring and bonding material, die attachment techniques and die attachment materials shall be adequate for space use. Workmanship and production The components shall show good and reproducible workmanship, which is an indication of stable and reproducible processes. Testing method for outgassing testing The method used for testing the outgassing of components should be equivalent to or similar to those in ECSS-Q70-02A or ASTM-E The general outgassing limits allowed are: TML (Total Mass Loss) < 1.0% CVCM (Collected Volatile Condensible Material) < 0.10% RML (Recovered Mass Loss) < 1.0% In some cases, the allowed limits might be lower due to special application conditions inside the equipment, e.g. in equipment using optical components. However, in some cases it might be allowable to use components with outgassing values higher than the above-mentioned limits. This shall only be allowed if the total amount of outgassing material used in the space equipment is comparatively low. This has to be verified on a case by case basis for each individual project. Prohibited Materials Based on their nature and their behaviour in space, the following materials should be avoided as far as possible: Tin coatings with less than 3% lead electroplated or fused (when surface is exposed to vacuum) (although components with pure tin coated leads can be used if the leads are 100% dipped in tin-lead solder before use) Cadmium, zinc or selenium except in hermetically sealed packages Mercury and other compounds of mercury Lithium Magnesium DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

28 Radioactive materials Polyvinylchloride Materials subject to reversion Materials which evolve corrosive compounds Component types and component constructions prohibited for space use The following component types or components constructions should be avoided for use in space programmes: Point contact or whisker diode construction Dice without glassivation Unpassivated power transistors Electrical crystals with mounting at less than 3 locations around the crystal periphery Non-solid electrolytic capacitors, except CLR79 Wire-link fuses Hollow core resistors or capacitors Non-double welded relays Any part whose internal construction uses metallurgical bonding or solder joints with a melting temperature not compatible with end-application mounting conditions Assessment for specific space projects The materials and/or parts constructions prohibited might differ from project to project. In some exceptional cases, the use of prohibited materials or components is possible when it can be justified by the equipment manufacturer and is accepted by the prime contractor and/or the customer. This has to be verified on a case by case basis for each individual project. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

29 4.2.4 Radiation A. Description of Element The capability of the component to withstand radiation shall be determined and shall include: Total ionising dose tolerance SEE sensitivity For commercial parts, the values for total ionisation dose shall be determined for multiple lots and shall be measured on components in the same package as that to be used. The assessment limits for SEE behaviour are an average of different space programme requirements. B. Assessment Assessment Criteria Total ionising dose sensitivity 50 krad (estimated over multiple lots) and (where applicable) LET for SEU > 35 MeV.cm²/mg and LET for SEL > 75 MeV.cm²/mg and no SEGR occurred at 100% V DS at 40 MeV.cm²/mg and no SEBO occurred at 100% V DS at 40 MeV.cm²/mg The values are within the limits specified for the specific space project Neither of the above conditions is satisfied or sufficient information for an assessment is not available Acceptable for general use Acceptable for specific project use Not acceptable Risk analysis could be appropriate for this element if sufficient information is not initially available. Note the radiation limits given in the above table are applicable at parts level. In addition to the above assessment of the usability of the component, it is important to determine if the component requires radiation testing of each procured lot (Radiation Verification Testing (RVT)). The following general rule shall be applied in cases where radiation characterisation has been performed using the multiple lot method as described in part C. TID design margin between 1 and < 1.3 x measured threshold Use with RVT TID design margin 1.3 x measured threshold Use without RVT Where radiation characterisation data have been obtained from a single lot the following rule shall be applied: TID design margin < 1.5 x measured threshold Not accepted TID design margin between 1.5 and < 3 x measured threshold Use with RVT TID design margin between 3 x measured threshold Use without RVT DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

30 C. Supporting Information Applicability Radiation susceptibility and testing are principally applicable to integrated circuits, discrete semiconductor devices and quartz crystal oscillators. There are however a number of other radiation sensitive materials which, although not generally used in traditional space qualified components, might be found in commercial components. These include a variety of plastic materials which can display significant changes in their mechanical properties when subjected to irradiation. Procedure for assessment of total ionisation dose data In order to simplify the processing of commercial components foreseen for space use the following approach for multiple lot testing shall be used as far as possible. This approach is similar to the requirements in Paragraph of Military Handbook MIL-HDBK-814 (Ionising Dose and Neutron Hardness Assurance Guidelines for Microcircuits and Semiconductor Devices). Total dose data assessment will be carried out on small sample sizes (5 to 15 samples) out of different wafer lots. Care must be taken that the samples are really out of different wafer lots and not only from different packaging or inspection lots taken from the same wafer lot. Total dose data assessment shall be carried out for each sample separately. The test results for each parameter that is affected by total dose irradiation, shall be assessed by statistical methods. Mean value and standard deviation shall be calculated for each sample separately. The end points of parameter variation are then calculated for each parameter and for each sample. (This is an assessment of each individual lot) The number of samples of different lots, which shall be applied to characterisation testing, is not specified in the MIL-HDBK-814. However, in order to get a representative test result, it is considered that the number of samples (number of different lots) should be 3 or larger. Finally the end point of parameter variation over all production lots is assessed by the use of statistical methods. Assuming that this assessment will be carried out for a high confidence level, the obtained final end point shall represent the worst case of parameter degradation over all lots. Traceability requirements If radiation verification testing is required for total ionising dose, based on the assessment requirements as given in part B, then the lot traceability must be sufficient to allow all delivered parts to be traced back to their appropriate wafer processing lot. If radiation verification testing is not considered necessary for delivered lots then the traceability must still be sufficient to ensure that all delivered parts are made using the same processing as the assessed parts. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

31 Basis of measurement data Total ionising dose The testing used for the assessment shall have equivalent or similar requirements to those stipulated in ESA/SCC22900 or MIL-STD-883, Method The type of radiation source shall be as defined therein. Whether or not low rate dose test data is required depends on whether the technology of the component and/or similar components are known to be low dose rate sensitive. Existing test data used for assessment should not be older than 5 years and shall be representative of the technology, manufacturer, production line, process, design, etc. which will be applied for commercial component for space use. Whether the electrical parameter change limits applied in the total dose test data are appropriate can be assessed on the basis of limits for a similar traditional hi-rel space component type given in Table 7 of an ESA/SCC detail specification or applied in a MIL specification for radiation hardness assurance testing. Single event effects The testing for the data used for the assessment of SEE behaviour shall be equivalent to or similar to ESA/SCC or MIL-STD-883, Methods 1020, 1021, 1022 and Test methods, sample sizes and failure indication shall be equivalent to these standards. The data used for assessment shall not be older than 5 years and it has to be clarified that the technology, manufacturer, production line, process, design, etc. are representative of the commercial components foreseen for space use. Radiation Verification Testing RVT testing of total ionising dose sensitivity shall be conducted in accordance with the requirements stated in ESA/SCC or in MIL-STD-883, Method Part types or technologies that have been identified in accordance with any project requirements as sensitive to low dose rates shall be submitted to low dose rate testing. Displacement Damage Degradation Electronic devices may also suffer from displacement damage degradation when the spacecraft or satellite orbit is exposed to a proton environment. Although transistors and linear microcircuits may also be affected by this effect, it is primarily opto-electronic devices (CCDs, opto-couplers, etc.) which are typically categorised as sensitive. No fixed testing method exists yet for the assessment of proton induced damage in semiconductor devices. That part of the deposited energy which creates displacement defects (in the semiconductor s lattice structure) is called Non-Ionising Energy Loss (NIEL). The trapped proton flux spectrum is converted into a fluence of mono-energetic particles producing the same amount of defects (typically 1 MeV neutrons or 10 MeV protons). For convenience an equivalent fluence of 10 MeV protons in silicon is usually selected for any assessment. In defining the fluence at component (or semiconductor) level some shielding can be included and the value is typically expressed as a fluence of 10 MeV equivalent protons behind aluminium spherical shields of various thicknesses. The transmitted proton fluxes have been computed with NOVICE code for a silicon detector in a 1 m diameter aluminium sphere. For any mission this curve provides a lower Displacement Damage Equivalent Fluence of φeq (10 MeV, Si) = DDEF 10 MeV protons DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

32 For projects where displacement damage degradation is applicable all sensitive parts (bi-polar and opto-electronic devices) should survive the DDEF calculated for the mission. The acceptance of the parts should be based on displacement damage test data which are considered in addition to the total dose electrical parameter drifts in a worst case analysis. The data should be taken from neutron testing data bases and proton test results and equivalence between proton and neutrons can be deduced from the environment specification. If no data are available proton irradiation evaluation testing should be considered. Due to the extremely high cost of proton testing, however, the use of commercial versions of displacement damage sensitive components types will generally not be a realistic option. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

33 4.2.5 Process Control A. Description of Element Process control is a methodology used to detect defective processes prior to completion of assembly. This includes the preventive, monitoring and corrective actions conducted during a process run, with the intention to manufacture components that cover the quality and reliability requirements, while using adequate quality tools. Unfortunately direct assessment of process control is difficult because there is no single quantitative result or limit which can be associated with it. Also any quantitative results which a manufacturer might generate, or limits which might be applied, are normally treated as highly confidential proprietary information and are not released (but of course are used internally to control the processes as an intrinsic monitor of a process s or product s quality). B. Assessment Assessment Criteria The topics described in part C of this paragraph show satisfactory results when assessed The above condition is not satisfied or sufficient information for an assessment is not available Acceptable for general use Acceptable for specific project use Not applicable Not acceptable Further analysis is not considered appropriate for this element. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

34 C. Supporting Information The assessment of the key element "Process Control" is not possible by the estimation of an individual figure, or by the comparison with a specific limit. Therefore, the acceptability of this key element has to be judged on the basis of an assessment of the following related elements. Process Maturity Process Description and Documentation Wafer Level Reliability (for semiconductor components) Statistical Process Control (SPC) Defect Control Yield Analysis Design Rules Process Maturity Process maturity gives a measure of the stability and the reproducibility of a production process since introduction of that process to the market. It also covers the status of process improvement over the period of application due to lessons learned from previous production runs using the same or a similar production process. The following points shall be considered for assessment of process maturity 1. The history of the technology and processes used, including the date of establishment and any changes that have been introduced. 2. The justification for any changes which have been made to the technology or process, if applicable. 3. The volume of components manufactured by the same processes without major changes. 4. The date and history of changes to the production line, e.g. change of facility, change of production line, changes within an existing production line or the corresponding processes. 5. Feedback data from field experience, which may be correlated to the processes used for manufacturing. 6. The long term trend of AOQL, FIT rates and process capability figures (Cp, Cpk). AOQL and FIT rate should show a decreasing tendency and the process capability values should show an increasing tendency. No specific limits are given for the above mentioned points for assessment. The assessor has to make a decision based on his experience and on the data available, while considering the impact and the importance of the points for the key element that is under consideration. A baseline for the assessment may be to compare these points with the performance of a state of the art manufacturer or process, or with the best in class component or manufacturer. Process Description and Documentation This element is applied in order to verify that all activity for designing and producing a component as well as the test steps and the test data obtained during these procedures is well documented by the manufacturer. The following points shall be considered for assessment of process description and documentation: DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

35 1. The design of the component and the material used for the individual parts of the component are well documented in drawings which are under the configuration control of the manufacturer. 2. All processes used for production and testing of the component as well as the elements and variables that make up a process, such as equipment, personnel, materials, environment, etc., shall be documented. The manufacturer's documents shall be under configuration control. 3. The test data obtained during in-process control, final production testing or screening testing, if applicable, shall be documented and stored for a defined time period. 4. Notice of process changes shall be made available to the customers according to EIA/JESD-46-A or a similar standard. No specific limits are given for the above mentioned points for assessment. The assessor has to make a decision based on his experience and on the data available, while considering the impact and the importance of the points for the key element under consideration. A baseline for the assessment may be to compare these points with the performance of a state of the art manufacturer or process, or with the best in class component or manufacturer. Wafer Level Reliability For semiconductor components, Wafer Level Reliability (WLR) makes use of dedicated test structures which are fabricated with the products on production wafers and which are used to test the reliability of the products on that wafer. WLR test structures can often be designed so that measurements can be carried out before the wafers have been fully processed, giving an early assessment of the reliability of the production devices. The test structures are designed so that a specific failure mechanism is assessed by a specific test structure. In that test structure, changes due to the failure mechanism are accelerated so that an assessment can be achieved in a matter of seconds. It has been established that the quality and reliability of products is very much related to the lot processing. I.e. a small number of lots exhibit bad reliability performance. Wafer level screening and removal of lots with bad reliability performance can drastically improve the overall product reliability. This is one of the major advances in integrated circuit reliability control and has enabled manufacturers to reduce or eliminate expensive screening of many packaged devices. Due to the relatively short time required to conduct WLR measurements, the statistical basis for reliability prediction can be substantially increased. Statistical Process Control (SPC) Statistical Process Control is a system of established and documented measurements and inspections, which are carried out at pre-defined stages of the production. The obtained data shall be analysed and assessed. The test results shall be entered into feedback loops to other nodes of the production process, which enables the operational personnel to conduct corrective actions, if required, or to adjust the process in such a way that the outcome will be of sufficient quality and reliability. SPC is a generic term and covers many different methods and philosophies, e.g. control charts, capability indexes, Parts Per Million (PPM), six σ, attributive testing or testing by variables etc. Numerous papers and standards dealing with this subject are available. In many cases standards for SPC testing do not only specify statistical methods, they also include implementation and maintenance rules for such a system. These elements are not stand-alone DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

36 quality elements; they are elements of the overall quality system of the manufacturer. Therefore, it is not considered appropriate to specify the use of a specific standard or methodology. The identification or description of the kind of statistical methods applied is therefore also part of this element, together with their effectiveness for control of the production process and the introduced corrective actions resulting from the findings. The following points shall be considered for assessment of in-process control and SPC: 1. Assessment of capability figures shall be carried out according to the supporting information given at the end of this element. Further baselines for the use and application of Cpk are given in EIA The statistical rules and methods used by the manufacturer for the determination and calculation of SPC values and the assessment of their effectiveness shall be equivalent to or similar to those given in EIA/JEP-132, EIA-557-A, MIL-HDBK-683. For example, an audit checklist for a typical SPC system is given in annex C of EIA-577-A, or an evaluation guide for a supplier's SPC programme is given in chapter 5 of MIL-HDBK Critical production steps and production nodes for the technology and processes used shall have been identified by the manufacturer. 4. The SPC methods used must be able to control the intended quality goals of the manufacturer in an effective manner. That is, the sample size applied for statistics, the periods when they are repeated, either time dependent or volume dependent, the test parameters chosen for measurements, and the mathematics used for the calculation of the statistical values must be chosen in such a manner that there is enough test severity to demonstrate that process control is effectively achieved. 5. The in-process control / SPC shall be effectively embedded into the overall quality system of the manufacturer. Guidelines for that can be taken and derived, for example, from MIL- HDBK-683. In addition the in-process control / SPC system of the manufacturer shall be able to carry out any necessary corrective actions in an effective manner. 6. Components or technology specific in-process controls shall be equivalent to state of the art standard. 7. For integrated circuits the use of Process Control Monitors (PCMs), Technology Control Vehicles (TCVs), Dynamic Evaluation Circuits (DECs), etc. to monitor process quality. 8. For discrete semiconductors and integrated circuits the monitoring of wafer defect densities and distributions and the comparison of adjacent dice on a wafer. 9. The use of in-process tests and controls to detect and remove anomalous components at an early stage in the manufacturing process wherever this is possible. No specific limits are given for the above mentioned points for assessment. The assessor has to make a decision based on his experience and on the data available, while considering the impact and the importance of the points for the key element that is under consideration. A baseline for this assessment might be to compare these points with the performance of a state of the art manufacturer or process, or with the best in class component or manufacturer. If a manufacturer uses capability figures Cp and Cpk for in-process control of his process, then the following values for Cp and Cpk can be taken as guidance for the assessment of the process. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

37 Tolerance zone in σ units Cp Comments, with respect to state of the art technology Not acceptable Not recommended Acceptable standard Recommended Comparable to 6σ philosophy Process average to next tolerance limit in σ units Cpk Not acceptable Not recommended Comments, with respect to state of the art technology Recommended Minimum Cpk value which is comparable to the 6σ philosophy Good Excellent This value would be reached in the 6σ philosophy for processes which are stable and the average is located in the middle of the tolerance band Defect Control Because early and random failures are generally the result of defects in components, defect removal or reduction is the most effective means to increase the reliability of components. Some measures that are applied to control defects, mainly in semiconductor components, are: Fabrication in extreme clean room conditions so that particle contamination is reduced to a minimum. Effective monitoring procedures to control particle defects and processing defects Inspection procedures to detect defects. For example, visual inspection of chips or automatic optical pattern recognition techniques. (Commercial equipment is available for comparison of neighbouring dice). In addition to optical inspection, electrical measurements during manufacturing can also be used to identify defects at wafer level. Manufacturers have implemented a wide range of different measures for defect control. Defect control has become an important part of modern semiconductor manufacturing techniques. Visual inspection is the most well known method for defect control and a number of standards for internal visual inspection are available e.g. MIL STD 833 Method In military and space and some automotive applications 100% visual inspection of completed wafers is carried out. For commercial components, visual inspection is generally carried out on a sampling basis. A further possibility for visual inspection is the use of pattern recognition equipment to identify problem dice and then manual visual inspection to check those dice. Yield analysis DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

38 The manufacturers shall have procedures implemented in his manufacturing facilities and processes to determine the yield of the products for each production lot. Moreover, individual yield figure limits might be necessary for individual, critical process steps to come to an acceptable yield figure for the finished product. The application of yield limits at critical process steps is to be handled as a gating control for further processing, i.e. if minimum yield figures are not met, the lot has to be rejected and either scrapped or returned for re-processing (if this is at all feasible). In addition an analysis must be initiated to determine the root cause of insufficient yield, which will then be fed back to the critical process for appropriate adjustment. Accordingly a manufacturer shall have documented procedures for the disposition of lots or semi-finished products with yield outside of limits, which shall be defined for each product. Design Rules These shall consist of a set of rules, which are applied to each new design or design modification of a component or a part of a component, with the intention of designing high quality and reliability into the components. The applied rules shall be documented in an appropriate manner and shall be updated due to lessons learned from realised designs and from state of the art requirements. The design rules may either be very specific and only related to individual part types or part type families, e.g. specific rules for current density, power dissipation, field strength, etc for a specific technology or component, or they can be general rules, e.g. the use of design tools such as FMECA (Failure Modes, Effects and Criticality Analysis), DOE (Design of Experiments), etc. for products or processes. The following points shall be considered for assessment of design rules: 1. The manufacturer shall have established a set of design rules for each component, component family or technology used. 2. The manufacturer shall have established a set of design rules, which are applied for each new design, or design modification of a component, or part of a component (e.g. a die). The design rules shall be continuously improved and amended, e.g. state of the art design rules and lessons learned from realised design shall be implemented. 3. Process or construction FMECA or similar tools shall have been applied prior to implementation of new and modified processes or designs into the production process. Basic rules for conducting a FMECA are given in ECSS-Q30-02A. 4. The application of specific design rules for specific component types of families of components, or for a specific technology shall be considered for the assessment. The assessment of which design rules have to be used for which technology or process depends on the experience of the assessor with this subject. State of the art design rules shall be considered for the assessment and estimation of this element. 5. Design of experiments (DOE), factorial analysis, or similar design tools shall have been used for determination of new or changed processes or technologies prior to their implementation into the production process. 6. The manufacturer shall apply design models for worst case temperature and electrical extremes, and for rules of thermal design and of package design. 7. Implementation of feedback loops from design, material and process development activities into design guidelines shall have been implemented by the manufacturer. 8. For integrated circuits it shall be verified that each new or modified design will be checked as follows: - Design rule check of geometrical and physical data - Design verification by simulation DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

39 - Electrical, shorts and connectivity design rule check - Check of reliability design rules like electromigration and current density, reverse current drops, latch-up, SEU (Single Event Upset), hot electrons, ESD (Electrostatic Discharge), burnout, or back-gating, as applicable - Verification of full functional and parametric testability at wafer level and on packaged devices As a baseline for the assessment of the design rules applied at a manufacturer for a specific component or technology the following points may be considered: 1. For transformers, inductors and coils the requirements of MIL-STD-981 can be considered. 2. Design rules for discrete semiconductors, integrated circuits and hybrid circuits can be derived from the MIL performance specifications MIL-PRF-19500, MIL-PRF and MIL- PRF Guidelines for process FMEA is given in document EIA/JEP Guidelines for design tools like DOE, FMEA, finite element modelling and analysis, etc. are given in EIA/JEP-132. The examples given above for design rules are only a baseline; the application of specific rules depends strongly on the component type and on the technology used. No specific limits are given for the above mentioned points for assessment. The assessor has to make a decision based on his experience and on the data available, while considering the impact and the importance of the points for the key element under consideration. Therefore, it is highly recommended that the person carrying out this assessment has been involved with the technical aspects of parts procurement or with the production of this kind of components in order to have sufficient experience and skills to be able to make the assessment Reliability Assessment System A. Description of Element The reliability assessment system is a documented manufacturer's standard of the procedures, methods and test conditions which are used for obtaining reliability data on components, either by special reliability testing or by other means for evaluating reliability such as existing field data analysis for a similar component or technology. The basis for reliability calculations and the background and the justification for using the applied rules shall also be considered. The outcome of the assessment of the manufacturer's reliability assessment system shall determine whether or not there is sufficient justification and confidence that the manufacturer's reliability data have been determined in an adequate manner according to state of the art methods. B. Assessment Assessment Criteria Acceptable for general use The reliability system is based on state of the art means and inspires confidence that useful data can be derived from the system, considering the base lines given in supporting information in part C of this paragraph The above condition is not satisfied or sufficient information for an assessment is not available Further analysis is not considered appropriate for this element. Acceptable for specific project use Not applicable Not acceptable DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

40 C. Supporting Information Definition of failure For comparison of different data it is essential to have a clear understanding of what is defined as a component failure and how many different failure categories are defined. The assessor has to distinguish carefully between catastrophic failures, where a component is no longer working at all, parametric failures, where the component is still working but the performance is at least for one parameter out of the specified range, or drift failure, where the component is still working well, but at least one parameter has exceeded a specified drift limit after a specific period of operation. The nature of the failure as well as the limit which is exceeded have to be carefully considered by the assessor in order to guarantee that the calculated reliability figures can be used to make a comparison between different component types or manufacturers. Test conditions and acceleration factors The conditions which were applied during testing for reliability figures shall be well defined. The nature and the value of the acceleration factors used for the calculations, e.g. high temperature, higher voltage, higher current or higher power shall be clearly defined. There shall also be a justification, based on test results or on published state of the art theoretical considerations, that the conditions defined for testing and for use, and the resulting acceleration factors used, are applicable for the components. Additionally it should be checked whether the parts life tested to calculate the reliability figures were submitted to any burn-in prior to the test. If any burn-in testing was applied, then it should be verified whether procured parts will also be burned-in before delivery. If not, it must be verified whether the calculated reliability figures can be modified to allow for this or whether burn-in can be performed on all parts after procurement. The status of the components for which the data is applicable should be well specified. E.g. are the data applicable for packaged components, or are they only applicable for dice and a package related factor has to be added in order to obtain a comparable baseline. Standards for reliability data assessment As guidelines for the assessment of a reliability assessment system the standards and publications JESD-34, EIA/JESD47, EIA/JESP-122, EIA-659 or any other similar documents can be used. JESD-34 deals with failure-mechanism-driven qualification of silicon devices and EIA/JESD47 deals with stress-test-driven qualification of integrated circuits, whereas EIA/JEP- 122 provides the failure mechanisms and models for silicon semiconductor devices and EIA-659 gives support for failure-mechanism-driven reliability monitoring systems. Baselines to be considered The following points shall be considered for the assessment of the reliability system The nature of the failures considered for reliability system as well as the limits applied for the analysis have to be well defined. The testing conditions for reliability figures and the natures of acceleration factors as well as the applied values of acceleration have to be well defined and should be justified by appropriate means. The system shall have clear definitions for when a new or an updated reliability assessment for a component, a technology or a production line has to be conducted. E.g. for new or DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

41 changed components design, for new or changed technology, or for new or changed production line processes. The calculated reliability figures for a specific component or technology shall be updated after any new reliability assessment or verified for validity at least once a year. The methods, means and processes used by the manufacturer for reliability assessment shall be well supported by appropriate justification and background information. For integrated circuits does the manufacturer monitor reliability at wafer level by including appropriate test structures which can be used for highly accelerated on-wafer reliability measurements of the known failure mechanisms of the device? For integrated circuits is the correlation between wafer level reliability and component reliability well established and verified? Is failure analysis performed on field failures to provide additional information on failure mechanisms and reliability? No specific decision limits are given for the above mentioned assessment points. The assessor has to decide whether or not the system is able to deliver actual reliability figures with a high level of confidence, while covering all critical parameters under the temperature conditions used in the space equipment. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

42 4.2.7 Reliability Data A. Description of Element The values of failure rates, which were estimated and calculated by the manufacturer based on the manufacturer's reliability assessment system, are defined as reliability data. For comparability of assessed values obtained from different testing or application conditions the values shall be transformed to values for 55 C ambient package or case temperature considering all the acceleration factors applied during testing. B. Assessment Assessment Criteria The failure rates of the components are equal to or better than the values given in the supporting information in part C of this paragraph The values are within the limits specified for the specific space project Neither of the above conditions is satisfied or sufficient information for an assessment is not available Acceptable for general use Acceptable for specific project use Not acceptable If reliability data are available but it is uncertain how applicable they are to procured lots (e.g. reliability testing was performed on screened parts but procured parts are supplied unscreened) then further analysis could be appropriate. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

43 C. Supporting Information Baseline for failure rates The component failure rates used as a baseline for the reliability analysis of specific space equipments are traditionally those described in ESA PSS and MIL-HDBK-217. These rates can still be valid for current projects, even if the documents are no longer under configuration control and will not be updated. Other national or international documents or databases can also be used to provide suitable baseline figures. The target maximum failure rates for commercial components for general space use are stated in the table below, but actual values differing from these by an order of magnitude would still be acceptable for most space projects. These failure rates should be applied for a confidence level of 60% at a package or case temperature of 55 C. Component Group Proposed FIT rates in 1/10 9 hrs Resistors, fixed 0,3 Resistors, variable 0,5 Resistors, chip 0,3 Capacitors, fixed 0,3 Capacitors, variable 2,0 Capacitors, ceramic 0,5 chip Diodes, general 0,5 purpose, analogue, switching, rectifier, Schottky rectifier, Zener, voltage regulator, current regulator Diodes, Schottky, 1 detector, mixer; Si and GaAs Transistors, NPN, 1 W 0,05 PNP >1 W 1 Transistors, RF No specific value proposed Transistors, microwave No specific value proposed Transistors, FET, Si No specific value proposed Transistors, FET, GaAs No specific value proposed Integrated Circuits, digital, bipolar (G = Gates) Integrated Circuits, linear, bipolar (T = Transistor functions) 100 G 1, G G G G G T T T T 17 Component Group Integrated Circuits, digital, MOS (G = Gates) Integrated Circuits, linear, MOS (T = Transistor functions) Integrated Circuits, memories, RAM, bipolar Integrated Circuits, memories, RAM, MOS Integrated Circuits, memories, ROM, bipolar Integrated Circuits, memories, ROM, MOS Integrated Circuits, µp bipolar Integrated Circuits, µp MOS Hybrids Proposed FIT rates in 1/10 9 hrs 100 G G G G G G T T T T k 2,5 64 k k k k 3 64 k k 10 1 M 15 4 M k 4 64 k k k k 2,5 64 k k 3, k 6 8 bit bit bit 40 8 bit bit bit 60 No specific value proposed, depends on complexity DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

44 Consideration of burn-in testing If the above mentioned failure rates are achieved without any burn-in testing, then the components are considered to be applicable for space use without burn-in testing on the flight components. However, if the above failure rates can only be achieved by components after application of a burn-in, then the components should only be considered for space flight application if they have been burned-in before procurement or can be burned-in after procurement. The burn-in conditions for the space components shall be equivalent to or comparable to the burn-in conditions applied to the components used for failure rate testing. Age of the reliability data and verification of conformity of failure rate figures The most recent data used for reliability calculations should not be older than 2 years. If this requirement is not met there should have been at least a verification of validity of the reliability figure during the last year. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

45 4.2.8 Final Production Electrical Measurements A. Description of Element The final production electrical measurement is a 100% electrical testing of the components at the end of the production process with the intention to detect and remove all those components from the production lot which are unable to satisfy the electrical performance requirements given in the data sheet or the procurement specification. B. Assessment Assessment Criteria At least all critical electrical parameters of the components are submitted to 100% final production electrical measurements. Not all critical electrical parameters are 100% measured or sufficient information for an assessment is not available. Acceptable for general use Acceptable for specific project use Not applicable Not acceptable Further analysis could be appropriate for this element if it is not certain that all critical parameters are 100% measured by the manufacturer. As a risk control exercise it would be possible to perform 100% measurement of critical parameters on all flight parts after receipt. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

46 C. Supporting Information Test methods and parameters to be measured Neither the parameters tested nor the test methods used must be identical to those specified in the data sheet or the procurement specification. Final production electrical testing may either be performed by measuring the parameters specified in the data sheet or the detail specification directly, or by using substitute measurement methods and parameter limits, e.g. for better throughput. However, there must be a high correlation between the guaranteed performance and the substitute methods and limits used. This shall be demonstrated by the assessment of appropriate test data or by analysis reports. Ideally final production electrical testing should be performed to tighter limits than those specified in the data sheet (guard banding). In many cases there is a correlation between the amount of guard banding and the reliability of the supplied devices. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

47 4.2.9 Average Outgoing Quality A. Description of Element The average outgoing quality is the average proportion of non-conforming components, in parts per million, from a series of lots. The value of the average outgoing quality shall be determined by sample testing of finished components prior to shipment or storage. The method of AOQL determination shall be equal to or similar to a state of the art standard. The parameters to be measured should have been defined by the manufacturer. Assessing whether or not all critical parameters are covered has to be based on the experience and skills of the assessor. The average outgoing quality shows the average number of faulty components that are accepted for shipment even after they have been subjected to all production testing including final production electrical measurements. Possible reasons for shipment of faulty components could be test equipment temporarily functioning incorrectly or bad handling of components after production testing. Examples of these might be a component with a high internal leakage current being accepted because a bad high resistance test connection reduced the current, or a component being damaged by ESD. The AOQL values given below for general assessment have been derived from values required for traditional hi-rel space components and given in publications on commercial parts. B. Assessment Assessment Criteria Method for AOQL determination is state of the art and AOQL 50 ppm for electrical parameters and AOQL 100 ppm for mechanical parameters (but see part C of this paragraph) AOQL unknown or 50 ppm < AOQL for electrical parameters or 100 ppm < AOQL for electrical parameters (but see part C of this paragraph) or method for AOQL determination is not considered satisfactory or sufficient information for an assessment is not available Acceptable for general use Acceptable for specific project use Not applicable Not acceptable Further analysis could be appropriate for this element if it is initially assessed as not acceptable for any reason. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

48 C. Supporting Information Method of AOQL determination The methods and rules for calculation of the AOQL values shall be equivalent to or similar to the requirements given in EIA-554-A, EIA-554-1, EIA-554-2, EIA-591 and JESD16-A. All four documents deal with standards and baselines for the assessment of quality levels in parts per million (PPM). If none of these standards is applied it shall be verified that the calculation rules applied by the manufacturer are equivalent to or comparable to the requirements stipulated in those standards. Parameters applied for AOQL determination All critical electrical AC and DC parameters given in the procurement specification measured at room temperature and high and low temperatures should at least be considered for AOQL determination. In addition all mechanical parameters which are considered to be critical parameters should be considered for mechanical AOQL determination. For the estimation of whether or not a parameter shall be considered to be critical, either the specific conditions of application of the component in a space programme, or the parameters normally tested for equivalent or similar traditional hi-rel space components shall be used as a baseline. Test Methods and Procedures The test conditions for samples submitted to electrical testing for AOQL determination shall be applied according to the conditions stated in the data sheet and/or the detail specification. Electrical testing of components is often carried out by measurement of substitute parameters, especially for final production electrical measurements, in order to have an effective and quick method of measurement. For AOQL determination, such substitute measurements have to be avoided because one intention of AOQL determination is to assess the amount of delivered components not satisfying the specified performance requirements, and one reason for bad or high AOQL values might be bad correlation between limits and measurement methods for substitute parameters and the specified performance of the component. Relaxed Mechanical Requirements When performing the necessary testing to establish AOQL some manufacturers use a significantly smaller sample for mechanical testing than they use for electrical testing. This can mean that the figure for mechanical AOQL does not reflect the true AOQL, but is due to statistical limitations resulting from the small sample size tested. In addition some manufacturers include cosmetic defects, which have no effect on performance, as mechanical failures when determining AOQL. If either of these two cases apply the requirement for mechanical AOQL can be relaxed to 1000 ppm. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

49 Quality System A. Description of Element To provide confidence in the quality of the tasks performed and the product supplied, the manufacturer must have an established and maintained system for quality control and conformance which is described in a configuration controlled in-house document. The system must include mandatory requirements covering all design, manufacturing, assembly and testing of the components undergoing assessment, and the areas where these are performed. The requirements must also include placing equivalent requirements on all subcontractors which are used for any part of the processing. B. Assessment Assessment Criteria Quality system is compliant with ISO-9001 requirements (or equivalent requirements), or it contains only minor non-compliances which would not be expected to result in an inferior product and which could easily be rectified There is no defined quality system, or it does not meet the above requirements, or sufficient information for an assessment is not available Acceptable for general use Acceptable for specific project use Not applicable Not acceptable Further analysis is not considered appropriate for this element. Note that if two or more companies are jointly responsible for the production of a component, e.g. if it is designed by one company but manufactured by another, then each company must independently be able to meet the relevant criteria for its own activities. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

50 C. Supporting Information ISO-9001 The ESA/SCC quality system requirements are very closely based on those of ISO Therefore any quality system which complies with ISO-9001 requirements must also be largely compliant with ESA/SCC requirements and therefore acceptable for producing components for space use. Many quality systems which are not specifically described as being compliant with ISO-9001 might nevertheless be compliant with its requirements. This will most commonly occur if the quality system is based on requirements which have been copied almost unchanged from ISO (as is the case for ESA/SCC requirements). Equivalent Requirements Equivalent requirements can be based on ISO-9001, and therefore be effectively identical, or can be created independently of ISO-9001, but nevertheless define alternative quality system requirements capable of achieving the same results. Examples of requirements which are closely based on ISO-9001 are: AQAP-110, NATO Quality Assurance Requirements for Design, Development and Production (which refers to the ISO document for most requirements) QS 9000, Automotive Quality Management System (which is described as an enhanced version of ISO-9001 which reflects the needs of the automotive industry) DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

51 Traceability A. Description of Element Traceability is the capability of a Manufacturer to trace backwards from completed, delivered components and identify all the basic materials and processes used to produce them. It also includes the capability to then trace forwards to identify all other components made using the same materials or processes. Traceability is traditionally required for space components so that: if any defects are discovered in components then the use of other components from the same manufacturing lot or flow can be restricted. the results of any testing on components from a specific manufacturing lot or flow can also be used for other components from the same lot or flow. testing for radiation hardness, which can show an extremely high lot dependence for some component types, can be effectively performed when required (see Paragraph for a fuller discussion of the importance of lot definition and traceability with respect to radiation hardness assurance). B. Assessment Assessment Criteria A level of traceability can be demonstrated equal to that required for ESA/SCC or MIL space level qualified components OR If the traceability is assessed according to the scheme described in section C of this paragraph and all requirements are met All traceability requirements defined for a specific project are met, even if the ESA/SCC, MIL or section C requirements are not met None of the above conditions are satisfied or sufficient information to make an assessment is not available Acceptable for general use Acceptable for specific project use Not acceptable Further analysis is not considered appropriate for this element. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

52 C. Supporting Information Information needed for Assessment The level of traceability which a manufacturer maintains for its components can be assessed on the basis of: A manufacturer s statement, made in response to a request for information, which describes the traceability which he maintains. A manufacturer s quality assurance manual, manufacturing manual, or documented procedure(s) which describe and control the actions taken during component manufacture to maintain traceability. A sample of any documentation (traveller) which is produced for, and which accompanies, a production lot and which demonstrates the level of traceability. It is possible that some manufacturer s in-house documentation would not be supplied outside the company, but it would be sufficient if this was made available for inspection at the manufacturer s premises. Assessment of Information Any information which is received must be evaluated using the following table. Points allocated to manufacturers which meet various requirements Requirement Is the expression 'lot' well defined in the manufacturers documents? Is the definition of 'lot' such that different designs, die constructions, production lines or facilities are excluded within one individual 'lot' of a specific component type? Is the definition of 'lot' such that the components will be made out of the same materials charge and manufactured according to the same processes? If manufacturing or testing lots or dates can be determined, are the associated test personnel, equipment and data recorded? Are data and documents retained for a minimum of 5 years? Is the requirement met? Yes (or it is not applicable) No (or information not available) For each assessed manufacturer/component all five requirements must be met if the traceability is to be assessed as acceptable for general use. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

53 Specification A. Description of Element A specification is any form of configuration controlled document, or documents, which defines the components which have been, or are to be, procured or tested. It can be used as a contractual definition of which requirements have to be met by the parts which will be delivered by the manufacturer. The specification must define the components in enough detail for a potential procurer to be certain that they are what he wants for his application, and to be certain that any procured components will be essentially unchanged from those which were used to generate the assessment data. B. Assessment Assessment Criteria Documentation is configuration controlled as described in the Supporting Information and satisfactorily covers the following as an absolute minimum: Component Marking Acceptable for general use Acceptable for specific project use Not acceptable Mechanical Requirements - Package type and pin allocations - Maximum overall package dimensions Electrical Requirements - Limits for externally applied conditions - All critical DC parameters - All critical AC parameters Thermal Requirements - Maximum external temperature in which the component can be stored without risk of damage - Maximum external temperature in which the component can be operated without risk of damage - Maximum permitted internal power dissipation for the component above which there is a risk of damage Not Applicable Quality and reliability aspects - Information about the quality and reliability level of the component should be given (this must not necessarily be a specific FIT value, it could be some other information like a reference to an established reliability or a reference to the standard which is applied for quality and reliability control, etc.) Available documentation does not meet all the above criteria Further analysis is not considered appropriate for this element. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

54 C. Supporting Information Suitable forms of specification documentation A suitable specification is needed to closely define the component type which is undergoing evaluation for space use. Without such a document it is not possible for the organisation which initially assesses the component type for space use to have any certainty that future components with the same part type number will actually have the same performance. This would mean that any assessment results could only be applied to the already existing components used to produce the data on which the assessment was based. A suitable specification is also needed so that potential users of the component can determine whether or not it will meet the performance requirements for their intended application. For commercial components any available specification will normally take the form of a manufacturer s data sheet, which could either be an individual data sheet or part of a data book. A data sheet might be specific for one component type, or cover a range of components from which the type specific data can be extracted. If the commercial components are already being supplied to a major user with specific requirements, for example an automotive user, then the manufacturer might have accepted a procurement specification prepared by that user. Any such specification would normally contain additional information to that in the manufacturer s data sheet and could potentially also be used for space components. Its actual use would depend on whether it was released for use by third parties and whether the manufacturer could confirm that components supplied to third parties would be identical to those supplied to the user who prepared the procurement specification. If any deficiencies are identified during initial assessment then additional information, data or documentation could be requested from the manufacturer to rectify these. Any further material which a manufacturer supplied in response to such a request could, if it was confirmed to be generally applicable to the component type, be considered to form part of the component specification. Configuration control of specification documentation For the configuration control of whatever documentation forms the specification to be acceptable it must meet the following requirements. All documents which effectively form the procurement specification must have a reference number, issue number, date of issue, and/or any other identification needed to uniquely identify them. If any of the documents are described as Draft, Advance Information, Preliminary or anything similar, written confirmation must be available from the manufacturer that the contents are nevertheless accepted as a basis for procurement and will not be altered without customer notification. Every document must have been approved by an authorised signatory, either on the document itself or as part of an internal approval system. The organisation preparing any document must have an internal system for approving proposed changes before they are incorporated into the document. For documents which could have more than one issue the preparer must keep a record showing which issue is current and what changes have been made from previous issues. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

55 Delivery Time A. Description of Element Delivery time is the expected interval between placing an order for components and receipt of the components by the procurer. Commercial components could generally be expected to be in continuous or frequent production with ex-stock delivery. B. Assessment Assessment Criteria Production is continuous and/or parts are always available ex-stock Delivery time is compatible with the project schedule requirements for the specific use Delivery time is not compatible with the project schedule requirements for the specific use or sufficient information for an assessment is not available Acceptable for general use Acceptable for specific project use Not acceptable Further analysis is not considered appropriate for this element. C. Supporting Information None DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

56 5 BACKGROUND INFORMATION 5.1 Use of Commercial Components in Space Electronic components designed and manufactured for use in terrestrial non-military and nonspace applications (commercial components) are being increasingly used in space. This trend is a result of the rapidly shrinking supplier market for military and space components, the much improved reliability and the much lower cost of commercial components. In addition, many modern state of the art components are only available as commercial parts so that equipment manufacturers wishing to make use of the increased functionality and lower power consumption of new components, particularly integrated circuits, are forced to use commercial parts. In mini and micro-satellites, the low budget of these programmes often prohibits the use of conventional space qualified parts. Many programmes in Europe and the United States have made use of commercial and/or plastic packaged parts. Those programmes include amateur and low budget projects but also include projects like LANDSAT 7, SPARTAN, TDRSS, EOS, EO-1 and the Hubble service missions. They have also been used in commercial space ventures such as IRIDIUM, but have had only limited use in mainstream satellites such as those used for telecommunications. The previous use of commercial parts in space has demonstrated their usability, however, there have been some problems and failures. An effective assessment procedure is needed in order to determine the viability of a commercial part type either for general space applications or for a specific mission. In contrast to space qualified parts, many commercial parts have been designed for a more limited temperature range, are offered in SMD plastic packaging, have no lot identification and must be procured via distributors. In addition, specification and data-sheet values are often not well defined, the parts have short product life cycles and the radiation tolerance of the parts is in many cases unknown. These negative aspects of commercial parts are to a great extent counterbalanced by the excellent quality and reliability now achieved due to the high volume production of commercial parts. Indeed, the quality and reliability of many commercial parts is better than that obtained for space components because space components are in most cases manually packaged, bonded and tested and cannot profit from the advantages of automated production processes. An impressive array of measures to improve the quality and reliability of integrated circuits have been successfully implemented at the manufacturers. Those measures generally lead to improved designs, improved processing techniques or improved measurement and inspection procedures in order to reduce the number of defective components in the outgoing production. Examples of these measures are the introduction of wafer level reliability testing on production wafers, automated optical inspection of chips and the removal of abnormal chips, wafers or lots identified using ingenious techniques for analysing the results of the electrical measurements. Much improved control of the overall manufacturing process has been achieved by the introduction of statistical process control and in-process sampling techniques. Also the users of commercial components have contributed to their greatly improved quality and reliability. For example, by feeding the results of application specific testing and field failure analysis back to the manufacturers, the sources of these failures could be eliminated. Generally, the enormous growth in the commercial semiconductor industry and the vast amounts of people and money involved in the manufacture and use of these parts has lead to continuous improvement of their quality and reliability so that many components now exhibit excellent quality and reliability. The viability of commercial part types for space applications has to be assessed in a logical manner before a decision regarding their use can be made. The procedure described in this document is a scheme for the assessment of commercial parts based on documented information available on the parts and is intended as a tool for users and procurement agents. It can be extended by applying a further analysis and/or specific testing to cover any areas where insufficient data is available. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

57 5.2 Equivalence of Commercial and Space Qualified Parts Due to the major advances in the quality and reliability of commercial components, many commercial parts can be considered to be equivalent to or better than space qualified parts. The objective of the assessment procedure described herein is to identify commercial components that are at least equivalent to space qualified components. The approach used to assure the quality and reliability of commercial and space components is completely different so that equivalence means an equivalent level of confidence in the component. Although the quality and reliability of components successfully assessed using this procedure should be equivalent to those of traditional space qualified parts, it is possible that they will have reduced capabilities in such areas as their overall temperature range. Despite this it is anticipated that components successfully assessed using this procedure will be suitable for about 80% of the applications covered by the traditional space qualified components. The confidence in the quality and reliability of space products is achieved by evaluation, qualification, control of the manufacturing and subsequent screening and lot testing. For commercial components, those parts with a basically high level of quality and reliability must be selected and their ability to satisfy the additional requirements of space applications assessed or tested. Commercial components selected in this way can be used with an equivalent level of confidence to space qualified components. In general, the supplier market for space components is shrinking because many suppliers regard the space components market as a small niche market that detracts from their main business. As a result, many of the remaining space qualified products are manufactured using out of date technologies with associated quality problems. Some assembly and test houses have specialised on the assembly and screening of small quantities of parts for space applications using old stocks of wafers. It is obvious that these parts cannot obtain the level of quality and reliability attained by high volume commercial components. DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

58 Appendix 1 - Form Sheets Assessment Summary Sheet 1/3 Assessment Summary Sheet 2/3 Assessment Summary Sheet 2/3 DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

59 Assessment Summary Sheet 1 of 3 ASSESSMENT FOR GENERAL USE IN SPACE APPLICATIONS Part Type Part No. Manufacturer Package / Case Size Variant / Revision Reference Date Limitations Key Ele. No. Key Element Description Result (direct assessment) Result (indirect assessment) Risk control measures Overall result 1 Thermal 2 Mechanical? 3 Construction? Apply DPA 4 Radiation? Apply RVT 5 Process Control 6 Rel. Ass. System 7 Reliability Data Additional 168 hr burn-in 8 Final El. Test 9 AOQL 10 Quality System 11 Traceability 12 Specification 13 Delivery Time Legend: = Acceptable for general use; NO = Not Acceptable;? = Insufficient Info/Data; N/A = not applicable Final Disposition: The ref. part type is acceptable for general space use This assessment result is only valid for procurement with the risk control measures indicated. NOT ACCEPTABLE FOR SPACE USE!!! ORGANISATION Name Date DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

60 Assessment Summary Sheet 2 of 3 ASSESSMENT FOR SPECIFIC PROJECT USE PROJECT: Part Type Part No. Manufacturer Package / Case Size Variant / Revision Reference Date Limitations Key Ele. No. Key Element Description Result (direct assessment) Result (indirect assessment) Risk control measures Result after risk analysis Overall result 1 Thermal 2 Mechanical?? No suitable measures available NO NO 3 Construction? 4 Radiation? 5 Process Control 6 Rel. Ass. System 7 Reliability Data 8 Final El. Test 9 AOQL 10 Quality System 11 Traceability 12 Specification 13 Delivery Time Legend: = Acceptable for general use; NO = Not Acceptable;? = Insufficient Info/Data; N/A = not applicable Final Disposition: The ref. part type is acceptable for specific project use Project: This assessment result is only valid for procurement with the risk control measures indicated. NOT ACCEPTABLE FOR USE IN THE PROJECT!!! ORGANISATION Name Date DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC

61 Assessment Summary Sheet 3 of 3 Detailed description of risk control measures No. Risk control measures Detailed description Notes: DLR-RF-PS-003_ASSESSMENT_PROCEDURE_COTS_V1.1.DOC