MicrobondAntec. MicrobondAntec. Solder pastes, wires and ribbons for Die-Attach and Die- & Clip-Attach applications

Transcription

1 MicrobondAntec MicrobondAntec Solder pastes, wires and ribbons for Die-Attach and Die- & Clip-Attach applications MicrobondGecko Lead-free Die-Attach adhesive Microbond Electronic Packaging Materials 1

2 Every problem requires its own solutions and specialists who understand what the problems imply. It is not so much the search for patent solutions that prevail, but the implementation of skills into reliable, customer-specific processes. Umicore has the answers to your questions and, with MicrobondAntec, the appropriate solution. 1 Introduction Page Die-Attach and Die- & Clip-Attach applications Page 8 11 The MicrobondAntec Die-Attach and Die-& Clip-Attach solutions are developed by Umicore and are in many cases unique to the market. Umicore materials for a better life. 3 Processing of Die-Attach material Page Products Page Technical support Page Quality and certificates Page Page 35 7 Glossary

3 1.1 Materials for a better life 1.2 Customized solution Many of the things, which we consider routine today, were once the visions of a future-oriented company. With this motivating idea in mind, Umicore develops and produces solutions for a wide variety of technical applications. The products of Umicore are used in all important industrial branches, e.g., glass industry, petrochemistry, aviation and aerospace, automotive, electrical applications and electronics. As different as the applications of its products are, the solutions have one thing in common - highest quality. Umicore offers solutions which set new standards, products which are trend-setting in their functionality and future technologies that can be used reliably and safely. As you can tell, the future is something everyday to us at Umicore. As material suppliers Microbond EPM develops, manufactures and commercializes customized material solutions. These products offer Umicore customers high process yields and product robustness. It is Microbond EPM's priority to fulfill or exceed these challenging requirements. To recognize trends and quickly develop automated production processes is prerequisite to stay ahead of development. It sounds easy, but it is definitely a difficult job. This capacity for innovation at Microbond EPM is based on strong experience and know-how in material technology. Audacious ideas are what make it happen. Decades of innovation and experience in materials for Die-Attach and Die- & Clip-Attach applications From the start, we took three considerations to heart: customer satisfaction, innovation and product quality. These maxims guide our daily work since customer satisfaction can only come from quality products. ISO RoHS conform ISO 9001 ISO/TS WEEE conform 4 5

4 Pin Transfer Dispensing Screen Printing Power Electronics Clip-Attach Die-Attach 1 Soft solder wire for Die-Attach 2 Soft solder paste for Die-Attach and Clip-Attach 3 Hermetic sealing materials 4 Amalgam spheres for CFL and FTL Ultimately, Microbond EPM s customers care only about one thing the result they get with our product 1.3 Industrialization and production 1.4 Environmental aspects The know-how of Microbond EPM s staff also encompasses the conversion of its developments into smooth production processes. What is meant by "smooth?" Simply put: safe and reliable procedures, the latest systems and all-inclusive, in-house manufacturing. Microbond EPM s manufacturing processes and continuous production conditions provide the prerequisites for excellent product quality and maximum efficiency. Modern production is also characterized by a clear material flow, a well-organized structure and maximum flexibility. Microbond EPM recognizes that its commitment to success must also take into account the broader economic, environmental, and social impact of its operations. In its pursuit of sustainable development, Microbond EPM therefore acts on the given guidelines for environmental protection and environmental safety, provided by legislative frameworks, the Umicore Way and best practice. Consequently, Microbond EPM seeks to continually improve its environmental performance and facilitates and encourages responsible design, use and disposal of its products. The foremost interest in this respect is the avoidance of hazardous and environmentally critical elements and components, such as lead and mercury, within the products themselves. 6 7

5 Basic research, a broad range of process skills and innovative ideas form the basis for functional products and smooth integration. However, it is a love of detail and consistent quality management that make MicrobondAntec products what they are: the reliable individual solution in all Die-Attach and Die- & Clip-Attach applications! Aside from the product properties, one of Umicore s primary concerns during development is the easy integration of MicrobondAntec solutions into existing processes. Our motto is: customer first! 8 9

6 1 Example of power package assembled by means of Die- & Clip-Attach 2. Die- & Clip-Attach application Die-Attach process completion remains the key step in power packages to ensure product reliability. The automotive and aerospace industry keeps setting high reliability standards. Thermal and mechanical fatigue of electronic components primarily comes from successive on/off switching activity. The main challenge in this crucial application is to find the optimum combination of material performance and available process windows. This is where Microbond material technology makes the difference. The Die-Attach joint has three main functions. In the first place it ensures mechanical fixing of the die onto the lead frame. Moreover, it enables heat dissipation from the die to the heat sink and eventually permits electrical contact. Typical power devices involving the Die & Clip-Attach application are transistors, IGBTs or MOSFET. These packages are better known as: TO, SOT, SOD, SMA, SMB, SMC, PLCC, QFP, SOP, SOIC, SOJ. 2.1 Single and multi Die-Attach 2.2 Die- & Clip-Attach For power applications, the generated heat flow is so high that conventional adhesives and eutectic solder alloys do not fulfill reliability requirements or their melting points are too low. Therefore, high-melting point solder alloys are used. These alloys contain more than 85 wt.% of Pb and do not satisfy the requirements of the Restriction of certain Hazardous Substances (RoHS), which came into effect on July 1st, Since there is no established lead-free substitute on the market, the high-pb alloys belong to the exemption list of the RoHS for these applications (exemption 7). This article aims to give an overview of current Die-Attach products and processes and to look at new potential Die-Attach materials, which would satisfy the requirements of the RoHS. Recent developments to Die-Attach processes makes it possible to apply several solder dots and silicon dies. Depending on package design, varying technical challenges require innovative material solutions. It is the duty of the applied technology group to give appropriate technical support. Examples of technical assistance available at Umicore are given in chapter 5. This conventional Die-Attach application can be realized by means of different assembly processes. The process capability of different Microbond Die-Attach materials is explained in chapter 3. Due to the increasing reliability and productivity requirements of industry, recent developments to the Die-Attach process offer replacement of the conventional Die-Attach process in which wire bonds are used. This Die- Attach and Clip-Attach technology is depicted in fig. below. The replacement of wire bonds by a metallic bridge is at the origin of thermal conductance and current density enhancements. Microbond solder pastes play a key role in this Die & Clip-Attach technology. Wire Bond Silicon Die Solder Ribbon Die-Attach Die-Attach Joint Void free Consistent BLT No Clean-Low Residue Water Soluble Silicon Die Clip Leadframe Solder Wire Solder Paste Clip-Attach Clip-Attach Joint Die-Attach Joint 10 Fig.1 Scheme of typical advantage of Die- & Clip-Attach vs. conventional Die-Attach process using wire bonds Leadframe 11

7 α Zone PbIn5Ag J-Alloy PbSn2Ag PbSn PbSn5Ag PbAg Tab.1 Typical temperature profile in an eight-zone oven for wire dispensing in a Die-Attach application for a few specific alloy compositions Fig.1 Typical temprature profile for wire dispensing in a Die-Attach application 3. Processing Die-Attach materials Microbond solder wires can be dispensed onto the lead frame and, while solidifying, the die is attached to the lead frame. The Microbond solder paste or MicrobondGecko can be pin-transferred, printed or dispensed on to a lead frame. A reflow step of the solder paste will led to Die-Attach. 3.1 Processing Microbond soft solder wires Using a solder wire, die attachment is effected by a wire-dispensing process (figure 2 below) and is mainly used for die attachment followed by wire bonding. Fully automated equipment is available on the market. The solder wire is fed into a crucible and pressed onto the hot lead frame, which heats the tip of the wire and causes it to melt. The solder wire is then removed and a solder droplet remains on the lead frame. The lead frame is then further heated from the bottom in order to keep the solder droplet liquid. Then the die is pressed into the molten solder, leading to an overflow of solder around the die. This overflow is controlled by a tool. When the pressure on the die is released, the surface tension of the molten solder causes the solder to flow back beneath the die. The lead frame then passes through a cooling section and the die attachment layer solidifies. This flux-free process is very clean and does not require any cleaning process. In order to prevent the solder from oxidizing, die attachment is performed in a protective atmosphere. The wire itself needs to be free of contamination (free from oxide, free from organic contamination) in order to ensure good wetting and therefore a low void rate in the Die-Attach layer. Further wire processing options can be used to apply Microbond solder wire. A spanking step or the use of hollow crucible enable mechanical enhancement of wetting performance. Bond line thicknesses of approximately fourty micrometers or two mil are recommended. Depending on the selected alloy composition, different temperature profiles must be followed (see Fig 1). The lowest possible residual oxygen content in the oven is targeted to optimize the quality of Die-Attach solder joints. Indeed, typical process deviation such as voiding or insufficient surface coverage are triggered by the quality of the protective atmosphere. The wire is transported down to the lead frame The hot lead frame starts to melt the wire The required amount of solder is dispensed The wire is pulled back 12 Fig.2 The four steps of conventional solder wire dispensing process onto preheated lead frame 13

8 Jars Typical scheme of solder paste applied by dispensing Typical scheme of solder paste applied by stencil printing Typical scheme of solder paste applied by pin transfer Paste-loaded Pins Pin Array Spools Syringes Pin Transfer Screen Printing Dispensing Cartridge Squeegee Needle Screen Solder Paste Leadframe Flux Pad Wafer Paste Position Substrate 3.2 Processing Microbond soft solder paste Different processes can be used to apply Microbond solder paste. Depending mainly on package design, either dispensing or stencil printing or pin transfer can be adopted. Solder paste is a mixture of solder powder and flux. This flux can vary in chemical nature and also be called a vehicle Dispensing Paste dispensing consists in pressing the paste out of the syringe or cartridge through a fine needle or shower head tool. Depending mainly on the inner diameter of the nozzle, the pressure time and the rheology of solder paste, one or several dots of specific sizes are dropped onto the substrate Stencil printing Fig.1 Typical temperature profile of reflow process A squeegee presses the paste through the stencil openings. Depending mainly on the aperture geometry, the stencil thickness and the rheology of the solder paste, one or several dots of specific sizes are dropped onto the substrate Pin transfer A pin is dipped into a solder paste bath. The sticky paste is then transferred onto the substrate by means of a dripping process. Depending mainly on the pin geometry and the rheology of the solder paste, one or several dots of specific sizes are dropped onto the substrate Reflow Reflow is the action of joining materials by a controlled thermal process, which liqufies the bonding material. During the reflow process coalescence of solder particles takes place. These solder particles come together once the material heats to above the melting point. Due to surface tensions the flux surrounds the metallic solder dot. Cooling at the end of the reflow process triggers solder solidification, thus creating a strong metallurgical bond Cleaning To fulfill various industrial requirements Microbond offers different types of flux. No-Clean / RMA / RM This type of solder paste leaves residues. The quantity of residue depends on flux formulation. Owing to good surface-insulating resistance, No-Clean solder paste can be left without cleaning. However cleaning is also possible in the case of a zero residue requirement. Special chemicals can be recommended by the applied technology group to obtain optimum results. Cleaning equipment with pressure jetting or ultrasonic bath are most suited to get rid of flux residue. No-Clean Low-Residue / NCLR This type of vehicle leaves minimal flux residue on the substrate. Most residue is metal oxides. Therefore, this residue does not cause corrosion. Water Soluble With this paste, any binders remaining on the printed circuit after the reflow process can be removed easily with water. Optimum performance can be achieved with hot water. The flux residue is hygroscopic and therefore water-soluble. It should be cleaned as soon as possible after reflow. Cleaning equipment with pressure jetting or ultrasonic bath is most suitable to remove flux residues with water. 15

9 4. Products 4.1 Microbond soft solder wire Alloy Coefficient of thermal expansion Thermal conductivity Electrical conductivity Elongation to rupture Young s modulus Tensile strength Peak temperature [10-6 K-1] [W/m.K] [% IACS] [%] [GPa] [MPa] [ C ] [F] PbSn PbSn PbSn10Ag PbSn5Ag PbSn2Ag PbSn1Ag PbIn5Ag SnAg25Sb < Tab.1 Standard alloy compositions available from Microbond Additional alloys The compositions listed represent the commonly used soft solder alloys. In addition, Microbond can customize alloy compositions to fulfill specific requirements. The applied technology group can provide support for material selection and process capability. Specifically doped materials Specifically doped solder material involves the addition of a minimal amount (ppm range) of wetting enhancing elements. The controlled addition of these substances significantly improves the wetting and flowing properties of the alloy. It provides a higher production yield and reliable results

10 Quality grades & process compatibility SSD grade: Developed to match the SSD wire dispensing process. Highly pure material. Wire Diameter 0.25mm 0.30mm 0.40mm 0.50mm 0.60mm 0.76mm Tab.1 Diameter tolerances of soft solder wires Tolerance 0.025mm 0.025mm 0.050mm 0.050mm 0.050mm 0.050mm C2 grade: Developed to enable fine tuning in material process capability. Highly pure material with wetting agent at a very low concentration. Not recommended with SSD wire dispensing technology due to high clogging frequency. C3 grade: Developed to enable fine tuning in material process capability. Highly pure material with more wetting agent than in C2 grade. Not recommended with SSD wire dispensing technology due to high clogging frequency. Microbond soft solder wire is manufactured by a polydimethylsiloxan-free extrusion process. A special extrusion die offers tight control of diameter tolerance. Microbond soft solder wire is available in diameters ranging from 0.25 mm (10 mil) up to 1.02 mm (40 mil) with tolerances of, respectively, mm up to mm. Fig. 1 Extrusion of solder wire Solder Ribbon Die holder Ram Void free Consistent BLT No Clean-Low Residue Solder Wire Solder Paste Water Soluble Die Billet Container Pressure pad 18 19

11 Alloy composition Application Code P = Print D = Dispense T = Pin-Transfer PbSn10Ag2-D3-RM210-5 Vehicle Code WS = Water Soluble NC = No-Clean RM = Rosin Mildly Activated DA = Die-Attach Pb-free Die-Attach No Clean Water soluble RoHS conform Type 6 Type 3 Particle Size 2 = -200 (75μm) +325 (45μm) 3 = -325 (45μm) +500 (25μm) 4 = -400 (38μm) +500 (25μm) 5 = -500 (25μm) +635 (15μm) Tab.1 Nomenclature of Microbond solder pastes Metal Content 5 = 85% 6 = 86% 7 = 87% 8 = 88% 9 = 89% 0 = 90% 1 = 91% Alloy Coefficient of thermal expansion Tab.2 Standard alloy compositions available from Microbond Package capacity Thawing time at 25 C 10 cc 40 g 30 min 30 cc 100 g 60 min 6 oz 500 g 90 min 12 oz 1000 g g 90 min Tab.3 Standard packaging for dispensing applications Thermal conductivity Electrical conductivity Elongation to rupture Tensile strength Powder Size Designation Type Mesh Size (microns) 2-200/ / / / Tab.4 Correspondence between powder types and particle size distribution Peak temperature [10-6 K-1] [W/m.K] [% IACS] [%] [MPa] [ C ] [F] PbSn PbSn10Ag PbSn5Ag PbSn2Ag SnPb SnPb36Ag SnAg SnAg3Cu > SnAg4Cu Handling and storing recommendations Do not open syringes until ambient temperature is reached 4.2 Microbond soft solder paste Additional alloys The compositions listed represent the commonly used soft solder alloys. In addition, Microbond can customize alloy compositions to fulfill specific requirements. The applied technology group can provide support for material selection and the improvement of process capability. Standard packaging for printing Standard Delivery Forms Jars: 200 up to 2000 grams Chemicals and powders used within Microbond meet most stringent quality requirements. The criteria below are considered with highest contention: Oxide Content < 120 ppm Spherical particles Smooth surfaces Tight of particle size distribution Solder powder is manufactured by taking molten solder and using gas jets to disperse it into droplets or by an ultrasound-supported dropping process. Screening is used to separate the spheres by size. The function of modifiers Rheology modifiers are additives that influence the workability definition and flow behavior of the flux. They also affect slump characteristics and play an important role in preventing flux separation during long term storage. Typically, rheology modifiers are thixotropic in nature and also affect the viscosity and viscosity stability of the paste. The function of activators The activators purpose is to clean metal oxides and contaminations from metal surfaces during reflow. They also prevent the highly reactive molten metal from reacting with the atmosphere until the metal re-solidifies. Activators are typically acids and halide-free. 1 SEM picture of Type 3 solder powder 20 21

12 1 Production of soft solder paste Flux Production The components of the flux can be classified in four groups with following functions: Rosin Rosin is a natural material found in coniferous trees. It can be chemically modified to improve such characteristics as oxidation resistance. Rosin also acts as an insulator, which makes it ideal for no-clean formulations. Furthermore, rosin imparts tackiness to the paste that aids in ensuring that components do not shift during the assembly operation. Solvent The solvent acts as a carrier system for flux. It is very important to choose the right solvent or solvent blends because they affect service life, tack time, slump and the profile requirements. A low vapor pressure solvent can increase service life and tack time while a solvent with a low boiling point can vaporize explosively during reflow and cause excessive solder splatter. Microbond fluxes are formulated to utilize the solvents that give excellent tack and service life but do not require excessive preheating or soak times. The soft solder production process is called the Rheology Stabilization Vehicle Process (RSVP). In this process, first the chemicals such as rosin, solvent, activators and additives are mixed at controlled temperatures, specific speeds and intervals. After that, the solder alloy is added at a controlled rate, mixed at a specified speed and temperature for an exact amount of time. The paste is then screened in order to eliminate large particles. Prior to packaging, the paste is degassed and a sample is checked for large, plated particles. After packaging it is stored in freezers for shipment at -18 C to 0 C. Microbond soft solder paste is characterized by its consistently very low bubble content and high stability. Production procedure for solder pastes Production of vehicle or binder Quality check of vehicle: viscosity; FOG Production of solder paste by mixing powder in vehicle Filling up of degassed solder paste in syringes Quality Check: viscosity; metal load; solderability; dispensing behavior Stringent Outgoing Qality Check (OQC) apply to each external batch release. Solder balling, slumpy, metal load determination, viscosity are most common test methods used. Adhesive ISO 9001 Solder Wire Solder Paste Solder Ribbon TS ISO

13 Sample Minimal gauge Dot size Void rate Cu54-EP02-D 23 constant 1% Description Properties Reliability Cu60-EP02-D 23 constant 1% Cu70-EP01-D 23 constant 0 Cu75-EP01-D 23 constant 0 PbSn10Ag2 23 constant 5% Tab.1 Results of dispensing behavior and joint quality 4.3 Lead-free adhesive MicrobondGecko Microbond is a world leader in the production of Die-Attach materials. This puts Microbond in the position to develop a new product that may indeed be considered to be a break-through in the industry: MicrobondGecko. It is the world s first Die-Attach adhesive for power components totally lead-free and the first substitute for high lead content solders in high temperature Die-Attach applications. This adhesive series can be processed and tested like conventional high-lead solders. Compared to bonds made with solder pastes, these new adhesives exhibit significant advantages: for example they have a very low void rate, high adhesive strength and outstanding interface quality, providing high thermal fatigue resistance and therefore high package reliability. The changeover is uncomplicated, because the copper-enriched, adhesive bonds exhibit absolutely the same behaviour as traditional solder pastes with regard to application, bond quality, thermal conductivity and tem - perature resistance. So nothing has to be changed and all commonly used manu facturing equipment and test procedures continue to function in the accustomed ways after the changeover. The copper-filled adhesive pastes are lead-free substitutes for high lead content solder alloys for power electronics and they comply with the requirements of the RoHS. They are formulated for applications involving semiconductor assembly and Die-Attach using printing and highspeed, automated dispensing equipment. Composition Cu = wt.% Adhesive = wt.% Storage and Handling Shelf life time: 12 months (2 C 7 C) 6 months (20 C 25 C) (in original packing, unopened) Prior to use, allow 0.5 to 3 hours for the adhesive paste to come up to room temperature Paste properties Color: Copper Typical viscosity (1) : kcps Paste density: g/cm 3 Pot life: 1 week Application: dispensable and printable (1) Brookfield RVT, TC spindle, 5rpm, 25 C Cured properties Color: brown No voids in the adhesive joint No cleaning before wire bonding Thermal conductivity: 1 W/m.K Coefficient thermal expansion: below 103 C: 60 x 10-6 K -1 above 103 C: 110 x 10-6 K -1 Operating temperature: -55 C / 225 C Shear strength: >20 N/mm 2 Hardness: (HV1) The copper-filled adhesive paste series offers heat dissipation through the adhesive joint equivalent to that through a high lead content solder joint. This unique property, combined with an excellent adhesion and interface quality with both chip and lead frame, results in high reliability in power packages Application The copper-filled adhesive paste series is designed to be applied by conventional printing or by dispensing techniques. The paste should typically be dispensed in an X pattern, with the smallest recommended needle being gauge 23. It has been optimized to prevent needle clogging, tailing or dripping. The adhesive pastes have superior properties for use in Die-Attach on bare Cu lead frames, Ag-plated lead frames, Ni-plated lead frames and NiP-plated lead frames. Curing After printing or dispensing and chip placement, no pre-drying or baking is necessary. Curing should be at 150 C air for 20 minutes. Packaging The copper-filled adhesive paste series is available in jars (100g to 500g) or in convenient ready-to-use syringes (3cc to 30cc). Other packages may be available on request. Easy to dispense Low void rate Printable Say good-bye to soldering and welcome to power sticking MicrobondGecko Cu-filled Perfect joint quality 24 25

14 5. Technical support 5.1 Applied technology Microbond EPM gives high priority to a strong customer support. The most important element in this worldwide customer support is Microbond EPM s application engineering group. They interface and work in close co-operation with their partners. Based on their extensive experience and metallurgical and chemical capabilities, they are able to assist customers in choosing the most appropriate products for their application. Furthermore, Microbond EPM directs its attention to provide technical seminars for the customers. These seminars may be provided locally at their partners facilities. This function offers an occasion for customers, to identify possible issues and - together to find solutions that improve the processes. Additionally, Microbond EPM provides in-house testing facilities, which are in close cooperation with Research & Development, and provide excellent customized modification of the products to meet the specific requirements

15 5.1.1 Standards, references and training Information Another important element in this worldwide customer support is that Microbond EPM s application engineers are members of the professional societies and organizations that determine industrial standards. They interface with national and international bodies that work to provide guidance and information in close cooperation with global partners. Based on this close cooperation, they are able to offer assistance in areas of continuous improvement. Microbond EPM s global presence and customer diversity has permitted the development of a knowledge base for process improvements in many areas. By working with customers in developing new products or manufacturing processes, we are able to achieve global material solutions. Partnerships with our suppliers and cooperation with many equipment Microbond EPM s extensive knowledge base is able to adapt training seminars to focus on an individual customer s process. Trained in many of today s problem-solving techniques used in the industry, Umicore application engineers can provide assistance in solving process-related issues. Additionally, Microbond EPM provides a source for reference materials from literature, periodicals and electronic media Process improvement and problem solving manufacturers extend our capabilities beyond our products. Microbond EPM s history spans many decades, and the continuous interaction within the Umicore network offers understanding in additional areas and products relating to the electronics and high-tech fields. For solutions contact your Umicore representative. 5.3 Analytical capabilities The applied technology department is responsible for customer support. Microbond application engineers have specialized pieces of equipment to support key customers. In this section a few key items of available equipment are listed and presented Thermal characterization Dilatometer This device enables the determination of the coefficient of thermal expansion. The thermal characterization method consists of heating a sample and measuring the material expansion over time. This data is key to understanding the thermal fatigue mechanism of material. Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC) Both Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC) measure energy changes in materials. They are the most generally applicable of all thermal analysis methods, since every physical or chemical change involves a change in energy. DTA is the older technique. Peaks may be characterized by: 1. Peak position indicating start temperature of phase change 2. Peak size relating to the amount of material and energy of the reaction 3. Peak shape relating to the kinetics of the process Process Exothermal Endothermal Solid-solid transition * * Crystallization * Melting * Vaporization * Sublimation * Absorption * Desorption * Desolvation (drying) * Decomposition * Solid-solid reaction * * Solid-liquid reaction * * Solid-gas reaction * * Curing * Polymerization * Catalytic reactions * Tab.1 Examples of exothermic and endothermic process 5.2 Materials research and development The electrical engineering industry expects continuous product innovation and highest product quality. Microbond EPM contributes to the success of its customers by providing such new solutions. The basis for this is an international team of experts in both materials science and chemistry that addresses the ever-advancing customer expectations and actively seeks to enhance and extend the capabilities of Microbond products Mechanical characterization Alloy tensile strength and elongation It consists in characterizing deformation behaviour and determining tensile and yield strength. Short response time Technical seminars Strong metallurgical and chemical skills Worldwide support Extensive analytical capabilities 28 29

16 1 Scanning Working principle electron of microscope X-ray fluorescence 2 Scanning electron microscope Surface analysis SEM/EDX - Scanning electron microscopy and Energy Dispersive X-ray Microanalysis: Photographic imaging of the micromorphology of materials and identification of the composition of fine particles, grain boundaries, layer systems down to the submicrometer scale Major & minor component analysis ICP-OES - Inductively Coupled Plasma Optical Emission Spectrometry Component and impurity analysis in major or minor concentrations after dilution of (solid) materials. Solutions of dissolved samples are transferred as aerosols into the plasma (ICP). Aerosol particles are then atomized, excited and/or ionized at a plasma temperature of 5000 to 8000 K. Emitted light is analyzed mostly in a simultaneous spectrometer. Calibration is done via synthetic calibration solutions. ICP-MS - Inductively Coupled Plasma Mass Spectrometry Impurity analysis in trace or ultratrace concentrations after digestion of (solid) materials. Solutions of digested samples are transferred as aerosols into the plasma (ICP). Aerosol particles are then atomized and ionized at a plasma temperature of 5000 to 8000 K. Ions are transferred into the mass spectrometer. High resolution (sector field) or low resolution (quadrupol) mass spectrometers are used for the analyses. Calibration is performed using synthetic calibration solutions. GDMS - Glow Discharge Mass Spectroscopy is an extremely powerful tool for performing trace and ultra-trace elemental analysis on inorganic solid materials such as metals, semiconductors, ceramics, carbides, graphite, etc. As a direct solid sampling technique, it is capable of reaching detection limits far below most other analytical techniques (down to ppb level). The GDMS technique involves preparing a sample that is sputtered in an argon glow discharge. Sputtered neutrals are then ionized in the plasma, extracted from the source and accelerated down the flight path of a Nier-Johnson reverse geometry double-focusing mass spectrometer. In this process, ions are resolved according to their mass-to-charge ratio and detected on a combined Faraday cup/daly knob detector. This permits the matrix elements and trace impurities to be detected in the same experiment. XRF - X ray fluorescence When a primary x-ray excitation source from an x-ray tube or a radioactive source strikes a sample, the x-ray can either be absorbed by the atom or scattered through the material. The process in which an x-ray is absorbed by the atom by transferring all of its energy to an innermost electron is called the "photoelectric effect". During this process, if the primary x-ray had sufficient energy, electrons are ejected from the inner shells, creating vacancies. These vacancies present an unstable condition for the atom. As the atom returns to its stable condition, electrons from the outer shells are transferred to the inner shells and in the process give off a characteristic x-ray whose energy is the difference between the two binding energies of the corresponding shells. Because each element has a unique set of energy levels, each element produces x-rays at a unique set of energies, allowing one to non-destructively measure the elemental composition of a sample. The process of emissions of characteristic x-rays is called "X-ray Fluorescence", or XRF. In most cases the innermost K and L shells are involved in XRF detection. A typical x-ray spectrum from an irradiated sample will display multiple peaks of different intensities. The characteristic x-rays are labeled as K, L, M or N to denote the shells they originated from. Another designation alpha (a), beta (b) or gamma (g) is made to mark the x-rays that originated from the transitions of electrons from higher shells. Hence, a Ka x-ray is produced from a transition of an electron from the L to the K shell, and a Kb x-ray is produced from a transition of an electron from the M to a K shell, etc. Since within the shells there are multiple orbits of higher and lower binding energy electrons, a further designation is made as a1, a2 or b1, b2, etc. to denote transitions of electrons from these orbits into the same lower shell. The XRF method is widely used to measure the elemental composition of materials. Since this method is fast and non-destructive to the sample, it is the method of choice for field applications. Depending on the application, XRF can be produced by using not only x-rays but also other primary excitation sources like alpha particles, protons or high energy electron beams. Sometimes, as the atom returns to its stable condition, instead of emitting a characteristic x-ray it transfers the excitation energy directly to one of the outer electrons, causing it to be ejected from the atom. The ejected electron is called an "Auger" electron. This process competes with XRF. Auger electrons are more probable in the low Z elements than in the high Z elements. Atom of a heavy element P O N M L K Ejected electron X-ray fluorescence Kα X-ray fluorescence Kβ 30 31

17 ISO RoHS conform ISO 9001 ISO/TS WEEE conform 6. Quality certification 6.1 Product quality is our highest priority. Our leading edge in quality control and quality assurance equipment ensures compliance with the high demands placed upon our products by our customers. 6.2 Management system, certificates and continuous improvement Microbond EPM maintains an integrated management system that is certified in accordance with ISO 9001, ISO and ISO/TS standards. Moreover, Microbond EPM is involved in Group-Work with Kaizen activities and a Zero-Defect program, as integral aspects of its approach to Total Quality Management. It is also committed to the goals of Responsible Care. Continuous improvement is the nucleus of Umicore staff culture. Product parameters such as composition, mechanical and thermal properties and rheology of each specific solder product, flux, brazing product, amalgam or adhesive are investigated and made available to customers in the form of a quality certificate. Wetting and soldering tests are conducted under application-specific conditions. Component and impurity analyses are conducted with state-of-the-art analytical equipment

18 We are a world class supplier of microelectronic packaging materials. As a strategic niche materials supplier to major companies in the global semiconductor, electronic component and high performance electrical device industries, we strive to be our customers preferred partner in their demanding applications. Our top priority is to deliver high performance, top quality materials to meet our customers requirements for their sophisticated systems. We also focus on meeting our markets demand for environmentally friendly products. Justified by our strong applied technology skills, our customers grant us insight into their complex systems. This allows us to continuously advance our products and skills. Through sustainable inside and outside growth also into new niches, EPM strives to attain stable profitability for its business. This helps us to be independent of the electronic industry s cyclic movements. Glossary Cooling In the last zone the workpiece is gradually cooling down to solidify the solder. This occurs as the alloy passes the eutectic temperature. The rate of cooling is as important as the rate of heating. It has to be carbully controled to prevent the assemblies from warping or a heat shock. Flux An essential chemical employed in the soldering process to alleviate solder wetting by reducing superficial metal oxides. PDMS - Polydimethylsiloxane It is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological (or flow) properties. Preheating This is the first step of the solder process. The preheat section is where the solvent in the paste begins to evaporate. Reflow In this zone the intermetallic is formed. This is the part of the process where the maximum temperature is reached. The most important consideration is peak temperature, which is the maximum allowable temperature of the entire process. This temperature is about 30 C - 50 C higher than the melting point of the solder. At this time the vehicle reduces surface tension at the juncture of the metals to accomplish metallurgical bonding, thus allowing the individual solder powder spheres to combine. Also, it now protects the substrate and then migrates out of the molten solder. Resin Also known as binder or vehicle, this resin is a synthetic product and has the same function as rosin. Resin or rosin is a key element in flux composition. Rosin A solid resin obtained from pine trees which, in the pure form, but usually with additives, is frequently used as a flux. Also known as colophony, it is usually named according to its source, e.g., gum rosin; wood rosin; and tall oil rosin. The principal constituents isolated from rosin are carboxylic abietic and its isomers, such as primaric acid. The acids may exist in rosin as acid anhydrids. The mixed acids are known in the trade as rosin acids or resin acids, the two terms being used interchangeably. Soak In this section the removal of solder paste volatiles and the activation of the fluxes take place; it is where the flux begins oxide reduction on the components. At the end of the soak zone, just before the reflow zone, thermal equality of the entire module is desirable. Thixotropy The tendency for the viscosity of a liquid to be shear rate-related. When a liquid is rapidly shaken, brushed, or otherwise mechanically disturbed, the viscosity rapidly decreases. Viscosity The property of a fluid whereby it tends to resist relative motion within itself. A thick liquid such as syrup has a high viscosity. Raleigh Glens Falls Perafita Paris Casablanca Hanau Budapest Mumbai Seoul Shanghai Bangkok Taipei Tokyo Manila Singapore Production Johannesburg Melbourne Marketing & Sales in all major markets Applied Technology 34 35

19 China Umicore Marketing Services (Shanghai) Co., Ltd. Microbond Electronic Packaging Materials Unit A1, 18/F, Zao-Feng Universe Building, No West Zhongshan Road, Shanghai , P.R. China Phone: Fax: Germany Umicore AG & Co. KG Microbond Electronic Packaging Materials Rodenbacher Chaussee 4 P.O. Box Hanau (Wolfgang) Germany Phone: +49 (6181) Fax: +49 (6181) epm.europe@eu.umicore.com India Umicore Marketing Service India Microbond Electronic Packaging Materials 406, Marker Chamber V Nariman, Mumbai India Phone: Fax: epm.india@umicore.com Japan Umicore Japan KK Microbond Electronic Packaging Materials 2-3, Kita-Aoyama 1-Chome, Aoyama Building 5F, Minato-ku, Tokyo, Japan Phone: Fax: epm.japan@ap.umicore.com Korea Umicore Marketing Services Korea Co., Ltd. Microbond Electronic Packaging Materials 3nd Floor, Ebenezer B/D , Seocho-Dong, Seocho-Ku Seoul, Korea Phone: Fax: epm.korea@ap.umicore.com Singapore Umicore Precious Metals (Singapore) Pte. Ltd. Microbond Electronic Packaging Materials No. 2, Corporation Road, #06-16/17 Corporation Place (Lobby A) Singapore Phone: Fax: epm.singapore@ap.umicore.com USA Umicore USA Inc. Microbond Electronic Packaging Materials 3120 Highwoods Blvd., Suite 110 Raleigh, NC USA Phone: Fax: epm.americas@am.umicore.com 36 The information and statements contained herein are provided free of charge. They are believed to be accurate at the time of publication, but Umicore gives no warranty with respect thereto, including but not limited to any results to be obtained or the infringement of any proprietary rights. Use or application of such information or statements is at the user's discretion, without any liability on the part of Umicore. Nothing herein shall be construed as a license or recommendation to use that infringes any proprietary rights. All sales are subject to Umicore s General Terms and Conditions of Sale and Delivery Umicore AG & Co. KG. Printed in the Federal Republic of Germany e