0. Table of contents. Author: Wim van den Einden

Transcription

1 Document nr. : WimEin V01 Page nr. : 1 Author: Wim van den Einden 0. Table of contents 0. Table of contents Changes compared to previous versions Safety Emergency Off (EMO) Alarm Signals Buzzer / LED Touchscreen Light tower TSC-2 Alarm menu Light tower signal description (optional) Chemicals General information Atmospheric processes Anneal N 2 anneal N 2 O 2 anneal N 2 /H 2 (Forming gas) anneal Wet N 2 anneal Wet oxidation Silicon dioxide (SiO 2 ) from Pyrogenic Oxidation (H 2 and O 2)... 9 Silicon dioxide (SiO 2 ) from DI water injection Silicon dioxide (SiO 2 ) from Dry Oxidation (O 2 ) Cleaning and oxidation processes using TransLC TM and O Overview atmospheric processes General information LPCVD processes TEOS Stochiometric Siliconnitride from NH 3 and SiH 2Cl Low stress Siliconnitride (SiN x ) from NH 3 and SiH 2Cl Flat Polycrystalline Si from SiH Doped Polycrystalline Si from 1% PH 3 /Ar and SiH SIPOS from SiH 4 and N 2 O Overview LPCVD processes Equipment Operation manual Load or Unload process wafers Load process wafers Unload wafers Login TSC TSC Selecting a new process recipe Touchscreen TSC Start/Continue a new process recipe... 26

2 Document nr. : WimEin V01 Page nr. : Touch screen TSC Stop a running process recipe Touch screen TSC Abort a running process recipe Touch screen TSC Edit Variable Process Command Touchscreen TSC Clear Alarms Required action Touchscreen TSC Rules & Regulations Instruction and test... 46

3 Document nr. : WimEin V01 Page nr. : 3 1. Changes compared to previous versions Date Page number New version number Description /01 First version with Document number 2. Safety This section contains a brief description of the safety features of a Tempress Horizontal Diffusion System for the operator. Operators must have a general knowledge of the technology involved in diffusion systems. They should understand safety practices outlined in this manual. 2.1 Emergency Off (EMO) Emergency Off (EMO) buttons are located around the system at accessible locations according to EN , especially EN 418. Pressing an EMO button turns off all power to the system except to the fans on top of the furnace. This prevents fire hazard as a result of high heat concentration in the furnace cabinet. Also those parts that are connected to a UPS facility remain operational. Press the EMO button when a person is in danger, when there is a fire, a water leak or any other event that could be hazardous to life. 2.2 Alarm Signals Alarms and alerts generated by tube controls are presented in several ways: Buzzer / LED Touch screen Light tower TSC-II Buzzer / LED Visible and audio alarm signals are generated by the DPC, DTC and the DMC. The visible signals will be presented with a LED, located below the buzzer position as shown in Fig Each tube process is represented by one LED and buzzer combination.

4 Document nr. : WimEin V01 Page nr. : Touchscreen The visible alarm signals will be presented on the touchscreen bottom line. Alarms on the touchscreen are always in combination with an audio signal. Touching the screen deactivates the audible signal. A new Alarm or alert will not activate the audible signal again before current alarm has been solved Light tower Alarms generated by the DPC, DTC and DMC will be made visible by three colors. Each color of the light tower represents particular circumstances. Green represents safe, operational condition. Yellow represents warnings and alerts Red represents alarms See section 2.3 for a full description TSC-2 Alarm menu Activating the alarm menu gives an overview of all active and passed alarms during the process. In case of an active alarm the Alarm button start flashing on and off. 2.3 Light tower signal description (optional) Two light towers, one on top of the loadstation in the cleanroom and one on top of the furnace in the grey-room, are installed for fast anticipation on the status of the (production) process. This section describes the function of each light and its relation to the tube status. A light tower is (default) comprised of 3 lights: from top to bottom RED, YELLOW and GREEN. The green and red light can indicate 2 signals: 1) OFF 2) ON

5 Document nr. : WimEin V01 Page nr. : 5 The yellow light can indicate 2 signals: 1) OFF 2) BLINK Figure: Default light tower configuration The light tower is controlled by a tower signal PLC that receives its commands from the various controllers, among others DPC/DTC/DMC, Excess temperature controller, gas detection system alarm and the TSC Host control. In case the EMO-switch is activated or a power failure occurs for more than 4 seconds, the power supply to the furnace will stop and also the light tower will be off. The tower signal PLC is programmed by Tempress Systems Inc. and is not adjustable by customers. Signal Mode Description Green ON Operational No warnings or messages OFF Not operational Yellow BLINKING N2 pressure-switch No N2 gas flow detected Air pressure switch No Air flow detected Torch temp (750) The torch temperature has to exceed 750oC Torch Flame failure There is no flame, the H2 valve will be closed Torch H2/O2 ratio The H2/O2 ratio exceeds the safety value Torch shell The skin temperature of the torch is too high Temperature sensor powerpack Temperature powerpack is too high Bubbler temp Bubbler temp is too high Bubbler level Fluid level is too low O2- low O2 flow is too low

6 Document nr. : WimEin V01 Page nr. : 6 Exhaust (Low/High) Exhaust flow out of limits Limit alarm (only if programmed in the process Actual value is out of limits recipe) Wait for operator (only if programmed in the Operator action is required to continue process recipe) Process is finished Boat manual Servo driver is in manual mode Maintenance mode Maintenance mode is activated OFF No alarm and/or alert Red ON Excess temperature controller has been activated Tube is overheated Leakage detection A gas or water leak has been detected OFF No alarm and/or alert No actual dangerous or hazardous situation 2.4 Chemicals Table: Chemicals that are being used in the atmospheric and lpcvd furnaces. Formula Name Dangerous H 2 Hydrogen Yes O 2 Oxygen No N 2 Nitrogen No N 2 O Nitrous oxide (laughing gas) Yes 1% PH 3 / Ar Phosphine Yes Trans-LC (*) Trans 1,2 Dichloroethylene Yes SiH 4 Silane Yes NH 3 Ammonia Yes (C 2 H 5 O) 4 Si tetra-ethyl-ortho-silicate Yes SiH 2 Cl 2 (DiChloroSilane Yes Detailed information about these chemicals can be found in the corresponding Material Safety Data Sheets (MSDS). (*) Trans 1,2 Dichloroethylene (Trans-LC) is an ozone-safe liquid chlorine source for use in silicon oxidation and tube cleaning. It features a low toxic hazard rating and is not restricted as an ozone depleting chemical.

7 Document nr. : WimEin V01 Page nr. : 7 3. General information Atmospheric processes An atmospheric furnace process is a heat treatment in an oxidizing, reducing or inert environment. 3.1 Anneal Annealing can be done at different temperature, different time or different environment to change the electrical, chemical and/or mechanical characteristics/structure of the surface or the bulk of layers N 2 anneal This is the standard anneal recipe for non-metal wafers/materials. N 2 anneal is used for diffusion or activation after implantation. It is also very often used to change the chemical (e.g. wet etch-rate) or mechanical properties of layers. N 2 is an inert environment. Depending on tube variable temperature up to 1250 o C N 2 O 2 anneal. Anneal in a N 2 /O 2 mixture e.g. comparable with air (20% O2). This is of course an oxidizing environment. Depending on tube variable temperature up to 1250 o C N 2 /H 2 (Forming gas) anneal A metal alloy anneal is normally used to reduce contact resistance between Silicon and Aluminium. Heat is supplied to the material so inter-diffusion can occur and a softer interface is generated. Hydrogen is a highly explosive gas at room temperature. 4% to 76% Hydrogen in air creates an explosive mixture. So even a 10%H 2 in N 2 mixture should be considered highly flammable and safety precautions must be taken. The supplied heat allows Silicon atoms to diffuse into the Aluminium, and Aluminium atoms to diffuse into the Silicon. As the solid solubility of Al in Si is very low, in the order of 1% or less, the maximum diffusion is already achieved after a few minutes. In addition, the metal alloy uses H 2 to passivate so-called dangling bonds. These are unfinished atomic bonds in the Silicon material and reduce the flow of electrons through the material, hence the name (contact) resistance. A H 2 burn off is required to safely burn remaining H 2. A low temperature heating element should be applied as the typical temperature is o C. A properly sealed door eliminates the need for heat barriers and flow baffle. Safety interlocks are required to prevent accidental boat out movement while H 2 is flowing.

8 Document nr. : WimEin V01 Page nr. : Wet N 2 anneal Anneal in N 2 / H 2 O environment, variable temperature up to 900 o C This process can be used for specific purposes, e.g. for annealing of MEMS devices with thick PECVD nitride layer which might crack during the standard N2 anneal. The N 2 / H 2 O process is very often used in combination with rather low annealing temperature and a slow temperature ramp. 3.2 Wet oxidation Thermal oxidation is very often used in the semiconductor industry to produce high quality Silicon-dioxide layers. The chemical reaction at higher temperatures converts silicon into Silicon-dioxide. The silicon-oxide layer is used as a mask during dopant diffusion, as a junction passivation and as an insulating field oxide. Thermal oxide incorporates silicon consumed from the substrate and oxygen supplied from the ambient. Thus, it grows both down into the wafer and up out of it. For every unit thickness of silicon consumed, 2.27 unit thicknesses of oxide will appear. Conversely, if a bare silicon surface is oxidized, 46% of the oxide thickness will lie below the original surface, and 54% above it. Process Steam (H 2 O) reacts with the Silicon top layer of the wafer into Silicon-dioxide as follows: Si + 2 H 2 O SiO H 2 Oxygen and steam must diffuse through the formed SiO 2, so the process will slow down in time, because Silicon-dioxide is a barrier to oxygen diffusion. Due to the aggressive nature of the hot steam thicker layers of Silicon-dioxide can be formed than using Dry Oxidation process in shorter time. Cross-wafer uniformity is normally very good, since the diffusion process is limited by the surface reaction part. The thickness uniformity is self-improving as the thickness increases. If relatively small wafers are used compared to the tube diameter an increased gas flow improves cross-wafer and cross-load uniformity drastically. The oxidation rate slows down as the oxide film thickens. As a rule of thumb, every 2x thickness requires 4x longer process times. The oxidizing ambient may also contain several percent of hydrochloric acid (HCl). The chlorine removes metal ions that may occur in the oxide. Typicalities To improve cross-wafer uniformity at the front and back of the wafer load it is necessary to apply a set of dummy wafers at each side of the load. A flow-baffle is required, as are 2 heat barriers.

9 Document nr. : WimEin V01 Page nr. : Silicon dioxide (SiO 2 ) from Pyrogenic Oxidation (H 2 and O 2) Pyrogenic Oxidation (also called Wet Oxidation) is used to create a thick insulating SiO 2 layer using the mono crystalline Si of the wafer. Due to the high temperature inside the tube or the external torch the added Hydrogen and Oxygen (ratio less than 2:1) will ignite. The formed steam (H 2 O) is highly acidic above 600 o C and reacts with the Silicon wafer into SiO 2. The thickness not only depends on the temperature and time, but also on the steam partial pressure. Default gasflows of H 2 and O 2 (a ratio of 1.5:1) yields a steam partial pressure of Higher steam partial pressure increases the thickness, lower steam partial pressures reduces the thickness. Chemicals Hydrogen is a highly explosive gas at room temperature. 4% to 76% Hydrogen in air creates an explosive mixture. Oxygen is the basic gas of every combustion reaction and therefore leaks are dangerous near hot areas Silicon dioxide (SiO 2 ) from DI water injection DI (de-ionized) water injection Oxidation (also called Wet Oxidation) is used to create a thick insulating SiO 2 layer using the mono crystalline Si of the wafer. The Silicon-dioxide layer is used as a mask during dopant diffusion, as a junction passivation and as an insulating field oxide. Chemicals De-ionized water is default available in all clean-rooms. The use of Hydrogen for the very thick oxide films requires up to and over litres of H 2. Replacing H 2 with DI water dramatically reduces materials costs at the expense of slightly longer processing times. 3.3 Silicon dioxide (SiO 2 ) from Dry Oxidation (O 2 ) Dry Oxidation is used to create an insulating SiO 2 layer using the mono crystalline Si of the wafer. The Silicon-dioxide layer is used as a mask during dopant diffusion, as a junction passivation, as an insulating field oxide and as a gate oxide. Due to its low oxidation rate it is typically used for an oxide film thickness up to 100 nm. Chemicals Oxygen is the basic gas of every combustion reaction and therefore leaks can be dangerous near hot areas. Process Oxygen (O 2 ) reacts with the Silicon top layer of the wafer into Silicon-dioxide like: Si + O 2 SiO 2 Oxygen must diffuse through the formed SiO 2, so the process will slow down in time, because Silicon-dioxide is a barrier to oxygen diffusion.

10 Document nr. : WimEin V01 Page nr. : 10 Cross-wafer uniformity is normally very good, since the diffusion process is limited by the surface reaction part. If relatively small wafers are used (compared to the tube diameter) an increased gas flow improves cross-wafer and cross-load uniformity drastically. Typicalities To improve cross-wafer uniformity at the front and back of the wafer load it is necessary to apply a set of dummy wafers at each side of the load. A flow- and a heat-baffle is necessary. 3.4 Cleaning and oxidation processes using TransLC TM and O 2 Trans 1,2-Dichloroethylene is a liquid source material used for in-situ generation of ultra high purity HCl in semiconductor operations such as silicon oxidation and tube cleaning. The chloride generated by Trans-LC aids in the removal of mobile ions and transition metals from the furnace environment, allowing the growth of oxides with low defect densities and mobile ion concentrations, and the significant improvement of minority carrier lifetimes. Chemicals Trans 1,2-Dichloroethylene is oxidised in the furnace to form HCl. The amount of chlorine entering the oxide layer is dependent on the temperature of the furnace operation step and the amount of total HCl generated from the Trans-LC in the furnace ambient. The chemical reaction is as follows: C 2 H 2 Cl O 2 2 HCl + 2 CO 2 Properties of C 2 H 2 Cl 2 : boiling point: 48 o C / vapour pressure at 20 o C: 250 Torr. Appearance and odour: It is a clear colourless liquid and has a sweet odour. The material is detectable at 0.08 ppm. Although Trans-LC is a chemical stable material, it can be ignited by heat, sparks and flame. It will decompose by exposure to air, light, and moisture. The material may cause irritation by contact. Process The amount of Trans-LC entering the diffusion tube must be controlled so that the cleaning or growth rate of the oxide can be maintained. To control the amount entering the tube, the temperature of the chemical must be maintained and the carrier gas flow must be controlled. In some applications, control must also include the ability to offset the effects of changes in atmospheric pressure by increasing or decreasing the carrier gas passing through the Trans-LC. Make sure that there is always enough oxygen flow in the tube during the process, because an insufficient oxygen flow may cause the formation of the extremely toxic COCl 2, also known as fosgene gas. Also, carbon deposit may occur. Typicalities The most common bubbler temperature used is 16 o C (although 20 o C can be used easily). It is necessary to maintain the bubbler temperature at least 5 o C cooler than the air around the tubing that connects the bubbler to the furnace to prevent formation of condensation in the line

11 Document nr. : WimEin V01 Page nr. : 11 leading from the bubbler to the diffusion tube. It is also important to choose a bubbler temperature that will allow operation of the gas controller within its calibration range. The Schumacher ATCS-TLC has a cooling capacity of o C below ambient temperature. Choose an appropriate temperature that enables the bubbler to operate properly. The most common carrier gas used is nitrogen. Argon also is used. Under no condition should oxygen ever be used as a carrier gas for this chemical or any other hydrocarbon material. Use of oxygen can cause bubbler failure due to the explosive mixture of the chemical vapors and oxygen within the headspace of the bubbler. The selection of an inert gas is required for safe operation. Normally a carrier flow rate of sccm is used for cleaning processes. 3.5 Overview atmospheric processes. All tubes can handle 100, 150 and 200 mm standard Si wafers, including small pieces. Processing different dimensions/materials can be possible but only in consultation with the tool-owner. Tube Temperature Process O34A1 SiC High temperature processing. Maximum temperature elements: 1300 C N 2 Anneal N 2 O 2 Anneal Wetox (pyrogenic) O34A2 Quartz Low temperature processing. Maximum temperature elements: 900 C O35B2 O36E2 Quartz Atmoscan Quartz SBVF Middle temperature processing. Maximum temperature elements: 1100 C Middle temperature processing. Maximum temperature elements: 1100 C O37C1 Quartz Middle temperature processing. Maximum temperature elements: 1100 C O37C2 Quartz Middle temperature processing. Maximum temperature elements: 1100 C O38D2 Quartz Low temperature processing. Maximum temperature elements: 900 C Dryox N 2 Anneal Wet (N 2 / H 2 O) Anneal Wetox (Di water injection) Dryox N 2 Anneal N 2 O 2 Anneal Wetox (progenic) Dryox N 2 Anneal N 2 O 2 Anneal Wetox Dryox PH 3 process N 2 Anneal Dryox N 2 Anneal N 2 O 2 Anneal Wetox (pyrogenic) Dryox N 2 Anneal N 2 O 2 Anneal N 2 H 2 Anneal

12 Document nr. : WimEin V01 Page nr. : 12 O38D3 Quartz Low temperature processing. Maximum temperature elements: 900 C Wetox (pyrogenic) Dryox N 2 Anneal N 2 O 2 Anneal N 2 H 2 Anneal Wetox (pyrogenic) Dryox

13 Document nr. : WimEin V01 Page nr. : General information LPCVD processes Low pressure chemical vapor deposition (LPCVD) is a chemical process used to produce high-purity, high-performance solid materials. The process is often used in the semiconductor industry to produce thin films. In a typical CVD process, the wafer (substrate) is exposed to one or more volatile precursors, which react and/or decompose on the substrate surface to produce the desired deposit. Frequently, volatile by-products are also produced, which are removed by gas flow through the reaction chamber. 4.1 TEOS TEOS is used to deposit an insulating SiO 2 layer in e.g. electrical applications. Chemicals TEOS, tetra-ethyl-ortho-silicate is a liquid at room temperature with a vapour pressure of 10 Torr at 50 o C. Due to this relatively low vapour pressure it easily condensates at cold spots and care should be taken to prevent condensation. TEOS is moisture sensitive so open contact with air should be avoided as much as possible. The TEOS molecule has sufficient O 2 built inside to allow a complete reaction. This means no extra O 2 is required for the formation of SiO 2 films (this is different for doped TEOS). Process Decomposition of tetraethyl orthosilicate (TEOS) at C Si(OC 2 H 5 ) 4 SiO H 2 O + 4 C 2 H 4. However, the reaction is very inefficient and a lot of TEOS exits the process tube un-reacted. This makes the process sensitive to pressure and temperature variations. The thickness decreases along the load due to depletion, a small temperature variation can be applied to improve this. The cross-wafer uniformity is also reasonably good, since the deposition process is limited by the surface reaction part. A decreasing process pressure does improve the uniformity, but a too strong reduction in process pressure results in a sharp decrease in deposition rate. If relatively small wafers are used compared to the tube diameter an increased gas flow improves cross-wafer and cross-load uniformity dramatically. Some reports indicate Carbon incorporation in the SiO 2 layer due to insufficient combustion of the TEOS molecule. This can be removed by either adding O 2 during the deposition or applying the standard 900 o C 30 min O 2 anneal that is required to densify the deposited SiO 2 film anyway. If extra O 2 is used during deposition: Si(OC 2 H 5 ) O 2 SiO H 2 O + 8 CO 2 large volumes of water vapours are produced, which cause polymerisation of remaining unreacted TEOS molecules and result in pumping problems. Therefore adding O 2 to undoped TEOS is not recommended.

14 Document nr. : WimEin V01 Page nr. : 14 Typicalities Due to the low vapour pressure condensation occurs at any cold spot in the line from the bubbler to the tube. Therefore, insulation and heating of the supply line is a necessity applying an increased temperature from bubbler to tube. Because the bubbler cabinet typically is close to the front flange the line remains short. To improve cross-wafer uniformity of the edge wafers it is necessary to apply a set of dummy wafers at each side of the load. An extra boat might be necessary. 4.2 Stochiometric Siliconnitride from NH 3 and SiH 2Cl 2 Nitride is used as an insulating and masking layer in e.g. electrical applications, and as an anti-reflecting coating in optical applications. Chemicals SiH 2 Cl 2, also known as DCS (DiChloroSilane), is a liquid at room temperature with a vapour pressure of 16 psi. Due to this relatively low vapour pressure it easily condensates at cold spots and care should be taken to prevent these. The residue of the reaction of DCS and NH 3 is NH 4 Cl. Some properties of NH 4 Cl: Sublimation at 320 o 1 atm. Sublimation at 120 o 100 mtorr. Two different forms are likely to occur: A white powdery form and a glassy solid form. The glassy form is what occurs as the gasses cool down abruptly on a cold surface. This is the form that is wanted on the cold-trap. The white form occurs from condensation in the gas phase, and will not be trapped by the cold-trap. Instead, it will be found at the inlet filter of the dry pump and in the exhaust of the same pump, or in the oil of a wet pump. Process The chemical reaction is as follows assuming a complete reaction: 3SiH 2 Cl 2 + 7NH 3 Si 3 N 4 + 6H 2 + 3HCl + 3NH 4 Cl The thickness uniformity decreases along the load due to depletion of DCS, much like depletion of SiH 4 in the poly-si process. A temperature ramp as high as of + and 30o C around the centre temperature is sufficient to overcome this problem. Cross-wafer uniformity is usually very good, since the deposition process is limited by the surface reaction part. A decreasing process pressure does improve the uniformity, mainly the cross load. If relatively small wafers are used compared to the tube diameter an increased gas flow improves cross-wafer and cross-load uniformity dramatically. Typicalities Due to the low vapour pressure condensation may occur at any cold spot in the supply line. Condensation leads to droplets formation, which cause MFC blockage. Heat tracing the supply line strongly depends on the customer situation. A long distance between the bottle cabi-

15 Document nr. : WimEin V01 Page nr. : 15 net and tube necessitates heating. This includes the bottle and lines supplied by the customer, and the lines in the gas cabinet up to the MFC. On the other hand, a small distance may not require heating and simple insulation may be sufficient. Therefore, insulation and heating of the supply lines needs to be addressed at each location. If it is a necessity apply an increased temperature from bottle to tube. Due to the lower pressure downstream the MFC heating is not required from the MFC to the tube and insulation is sufficient. As DCS reacts with NH 3 the residual product is NH 4Cl. That must be trapped using a coldtrap. These gasses should be cooled down with a shock, not with a gradual decrease. A cooled flange is required to extent O-ring lifetime, due to the high temperature of o C. Especially at unloading conditions, the door O-ring is likely to burn. Also, the balljoint O-ring receives a lot of heat, especially at pumping down conditions. However, a too cold flange will cause NH 4 Cl condensation, which shows as a white powder deposit on the flange. To improve cross-wafer uniformity in the first few wafers it is necessary to apply a set of dummy wafers at the gas inlet side of the load. An extra boat might be necessary. 4.3 Low stress Siliconnitride (SiN x ) from NH 3 and SiH 2Cl 2 The low stress silicon nitride process is similar to the stochiometric nitride process except for process temperature, process-gas flows and process pressure. As the SiH 2 Cl 2 gas-flow is increased the SiN x has an increased Si concentration. Varying the amount of Si in SiN x makes is possible to tune the stress. The stress of the low stress silicon-nitride is approximately 100 MPa (stochiometric nitride approximately 1000 MPa). Refractive index approximately 2.2 vs 2.0 for stochiometric nitride. 4.4 Flat Polycrystalline Si from SiH 4 A flat poly-si process is used in situations with a strong demand for exactly dimensioned grain structures. As diffusion source it is required to have small grains (more grain boundaries to diffuse along) and as bulk material in Thin Film Transistor (TFT) applications the grain structure is involved in the mobility of charge carriers (larger grain means less grain boundaries, less barriers to cross for the charge carriers and a higher mobility). Chemicals SiH 4 is a pyrogenic gas, which means it will burn spontaneously when it comes into contact with O 2 or air. It is also toxic, but generally it will burn before it gets toxic. Process Since the temperature is flat (610 o C, fine grain; 650 o C, coarse grain) and the reaction consumes SiH 4 (depletion) the thickness decreases along the load. This can be improved in basically two manners: by using a high flow of (inert) gases to dilute the SiH 4 and reduce its consumption. This will affect the growth rate since the partial pressure of SiH 4 is reduced. Or, use a specially designed set of injectors to create a homogeneous local SiH 4 concentration. Cross-wafer uniformity is generally pretty good, since the deposition process is limited by the surface reaction part. A decreasing process pressure does improve

16 Document nr. : WimEin V01 Page nr. : 16 the uniformity, both the cross wafer and the cross load. If relatively small wafers are used compared to the tube diameter an increased gas flow improves cross-wafer and cross-load uniformity drastically. Typicalities To improve cross-wafer uniformity of the edge wafers it is necessary to apply a set of dummy wafers at the gas inlet side of the load. An extra boat might be necessary. The injector design is crucial and consists of a tube with front- and back-flange, through which one long double-sided injector is placed. An extra injector position is available to add some extra SiH 4 at a specific position should that be required. 4.5 Doped Polycrystalline Si from 1% PH 3 /Ar and SiH 4 In situ doping of polysilicon involves adding doping gasses (e.g. PH3) to the lpcvd reactant gasses. The control of film thickness, grain size, grain orientation and deposition rate is greatly complicated / influenced by the addition of the dopant gases. Chemicals SiH 4 is a pyrogenic gas, which means it will burn spontaneously when it comes into contact with O 2 or air. It is also toxic, but generally it will burn before it gets toxic. 1%PH 3 /Ar, PH 3 (Phosphine) is extremely toxic. Process The process temperature of the doped poly proces is slightly higher compared to the flat poly process. Sheetresistance of the doped poly layer is 10 mohm/cm (500 Ohm voor 200 nm poly). After activation (actpoly recipe: furnace O37C1, o C) resistance goes down to 1 mohm/cm. Deposition rate is much lower compared to flat poly, partially caused by the much lower pressure (150 mtorr vs 200mTorr). 4.6 SIPOS from SiH 4 and N 2 O SIPOS (Semi-Insulating Polycrystalline Silicon) is a Low Pressure Chemical Vapor Deposition (LPCVD) process for the deposition of high resistivity Poly-Silicon layers, which are primarily used in the fabrication of high voltage semiconductor devices. SIPOS films overcome the disadvantage of SiO 2 films, such as accumulation of fixed ion and electronic charges at the SiO 2 /Si interface, charge retention in the SiO 2 layer and the high mobility of alkali ions at elevated temperatures and high electric fields. These problems cause reduced breakdown and sustaining voltage levels of high voltage devices, device instabilities and impaired reliability due to ion migration in the SiO 2 layer. SIPOS films are primarily used as field plates in high voltage devices to extend the high electric field at the PN junction/ SiO 2 interface over a larger distance. The equipment used for the deposition of SIPOS films is standard semiconductor LPCVD equipment. To obtain good thickness uniformity across the silicon wafers, a special cage quartz wafer carrier is required. The basic SIPOS process is very similar to other LPCVD processes. Controllable process variables are: SiH 4 flow, N 2 O flow rate, ratio of SiH 4 to N 2 O, Temperature (Range from 620 to 680ºC) and pressure.

17 Document nr. : WimEin V01 Page nr. : Overview LPCVD processes. All tubes can handle 100, 150 and 200 mm standard Si wafers. No-metal contamination allowed. Processing different dimensions/materials can be possible but only after consulting toolowner. Deposited layer LPCVD Deposition conditions Dep. rate Chemicals tube Temp. ( o C) Pressure (mtorr) (nm/min) TEOS (SiO 2 ) O34A ± 8 TEOS 120 sccm TEOS thin (SiO 2 ) O34A ± 4 TEOS 120 sccm Low stress nitride (SiN x ) O35B ± 4 NH 3 48 sccm / DCS 210 sccm Stochiometric nitride (Si 3 N 4 ) O35B ± 3 NH sccm DCS 60 sccm Flat poly (Si) O37C ± 8 SiH sccm n-doped poly (Phosphorus) O37C ± 1 SiH sccm 1% PH 3 /Ar 50 sccm Amorphous Silicon O37C ± 2 SiH sccm SIPOS (SiO x ) O37C ± 8 SiH sccm N 2 O 40 sccm

18 Document nr. : WimEin V01 Page nr. : Equipment The horizontal furnaces of Tempress Systems Inc. are developed according to the European directives for Machinery (98/37/EC), Low Voltage (73/23/EC) and EMC (89/336/EEC). The Tempress Diffusion system is a modular horizontal furnace designed to process (silicon) wafers as part of the manufacturing technology of semiconductor, optical, MEMS and solar devices. Figure 5-1 shows an example of a standard L-shape diffusion system with 4 process tubes shown without the partition of a clean-room wall. It is a right-handed system, defined according to the position of the furnace relative to an operator. Usually the system contains more than 1 tube. Based on the number and size of tubes, the system is referred to as a 2, 3 or 4 stack. All tubes operate fully independently. Figure 5-1 Schematic view of a right-handed 4-stack Diffusion System Main Power Cabinet. This is an example of a Tempress furnace stack. In our cleanroom we only have 3-stack diffusion systems.

19 Document nr. : WimEin V01 Page nr. : 19 Operator area description Figure 5-2 Schematic view of a right-handed 4-stack Diffusion System Buzzer / led Hot surface Light / Fan switch Wafers Touchscreen EMO Moving part The operator area is limited to the load-station only. Figure 5-2 shows the relevant items. The Loadstation part of a Tempress System should be placed in the clean-room. The Furnace and Gas cabinet can optionally be placed in the grey-room. To load wafers, several loader types can be implemented, including the (default) inline loader, the Amtech Atmoscan, and the backmounted softlander. To prevent particles on the wafers during the loading process, a constant horizontal laminar flow is created from the load-station into the clean-room. The load-station is powered by 220V and has an illuminated On/Off switch for the fans and the lights. The remote control cabinet in the load-station contains TFT-Touch-screens, one for each tube. These supply the user interface for communication with the Digital System Controllers (Digital Process Controller, Digital Temperature Controller and Digital Motion Controller).

20 Document nr. : WimEin V01 Page nr. : Operation manual Operator Instructions: This document describes the various procedures required for an operator. The procedures describe how to load and unload wafers, how to select a new process recipe, how to start/continue a process recipe, how to stop the timer of a running process recipe, how to modify Variable Commands when available and how to abort a running process recipe. Tube numbers and Tube recipes in this manual can be different to the current situation. 6.1 Load or Unload process wafers Loading and unloading process wafers on the paddle is required before and after each process run Load process wafers Place the wafers on the wafer carriers, depending on the situation with (vacuum) tweezers or a wafer transfer system. Pick-up wafer carriers with a pick-up fork or automated loading tool. Place the wafer carriers around the center of flat-zone as indicated on the load-station Unload wafers Warning Wafers and paddle are hot Allow the wafers to cool down. Pick-up wafer carriers with a pick-up fork or automated loading tool. (Amtech Systems S300) Remove the wafers from the wafer carriers, depending on the situation with (vacuum) tweezers or a wafer transfer system. 6.2 Login TSC-2 Changing login name may be required to link a process data to an operator and to precede processing of logging data.

21 Document nr. : WimEin V01 Page nr. : TSC-2 (1) Press ID to Login as screen until following screen appears: User login (2) Type the personal username and password (3) Press Login to login or Logout to logout

22 Document nr. : WimEin V01 Page nr. : 22 Note: A user is automatically logged out after 5 minutes of no activity 6.3 Selecting a new process recipe A new process recipe needs to be selected so the new instructions can be executed. A new process recipe can only be selected if the current process recipe is in Step Touchscreen (1) Return to the Main Menu by pressing ESC until the following screen appears: (2) Press 4 to access Tube control

23 Document nr. : WimEin V01 Page nr. : 23 (3) Press 6 to Select a process Recipe (4) Select the desired process recipe by entering its number

24 Document nr. : WimEin V01 Page nr. : 24 (5) Press Yes to confirm the question Sure to SELECT PROCESS recipe (Yes/No)? Note: Selecting another process recipe is only possible if the current process recipe is in Step TSC-2 (1) Select the desired tube form the pull-down menu or from the Overview screen. (2) Select Operations to access the operations screen

25 Document nr. : WimEin V01 Page nr. : 25 (3) Select the desired process recipe from the pull-down menu (4) Press Yes to confirm the question Are you sure to select another process recipe? Note: Selecting another process recipe is only possible if the current process recipe is in Step 0.

26 Document nr. : WimEin V01 Page nr. : Start/Continue a new process recipe Two different situations require the Start command. The first situation is starting a newly selected process recipe so it starts running from Step 0. The second situation is starting a process recipe that has been stopped or is waiting for an Operator instruction Touch screen (1) return to the Main Menu by pressing ESC until the following screen appears: (2) press 4 to access Tube Control

27 Document nr. : WimEin V01 Page nr. : 27 (3) press 2 to access Start/Stop Process Recipe. (4) press Start to start/continue the selected process recipe.

28 Document nr. : WimEin V01 Page nr. : TSC-2 (1) select the desired tube from the pull-down menu or from the Overview screen. (2) Select Operations to access the operation screen.

29 Document nr. : WimEin V01 Page nr. : 29 (3) press Start to start the selected process recipe from Step 0 (4) press Continue to start a process recipe that has been stopped or is waiting for an Operator instruction. (5) press Yes to confirm the question Do you want to start?

30 Document nr. : WimEin V01 Page nr. : Stop a running process recipe Stopping a running process recipe may be required to temporarily stop the process recipe. When activated, the Stop command will stop the timer while all given commands are maintained Touch screen (1) return to the Main Menu by pressing ESC until the following screen appears: (2) press 4 to access Tube Control

31 Document nr. : WimEin V01 Page nr. : 31 (3) press 2 to access Start/Stop Process Recipe (4) press Stop to stop the selected process recipe

32 Document nr. : WimEin V01 Page nr. : TSC-2 (1) select the desired tube from the pull-down menu or from the Overview screen. (2) Select Operations to access the operations screen. (3) Press Pause to stop the selected process recipe from the current step.

33 Document nr. : WimEin V01 Page nr. : Abort a running process recipe A manual Abort instruction may be required if the operator foresees a dangerous situation or a continuous looped process recipe needs to be reset to Step 0 to allow selection of another process recipe Touch screen (1) return to the Main Menu by pressing ESC until the following screen appears: (2) press 4 to access Tube Control

34 Document nr. : WimEin V01 Page nr. : 34 (3) press 3 to access Abort Process Recipe (4) type Yes to confirm the question ABORT (Yes/No) (5) type Yes to confirm the question Are you sure you want to abort (Yes/No)

35 Document nr. : WimEin V01 Page nr. : 35 (6) press Yes again to activate the abort command TSC-2 (1) select the desired tube from the pull-down menu or from the Overview screen. (2) select Operations to access the operations screen.

36 Document nr. : WimEin V01 Page nr. : 36 (3) Press Abort to abort the selected process recipe. (4) Press Yes to confirm the question Sure to abort? Caution Call immediately authorised person, after Ábort command has been used. The system should not be operated under any other circumstances.

37 Document nr. : WimEin V01 Page nr. : Edit Variable Process Command Variable Process Command can be used to quickly modify specific process settings. Only those lines in the process recipe that have been assigned as Variable Commands will be presented in a list. From this list the desired process setting may be modified. Variable Process Command can be set at all times until the recipe step is executed in which the specific Variable Command is programmed Touchscreen (1) return to the Main Menu by pressing ESC until the following screen appears: (2) press 4 to access Tube Control

38 Document nr. : WimEin V01 Page nr. : 38 (3) press 5 to access Variable Commands

39 Document nr. : WimEin V01 Page nr. : 39 (4) edit the desired process setting a. enter the corresponding line number b. modify to the desired setting c. press Return to confirm the modification (5) repeat step 4) until all desired process settings have been set (6) Press Esc to store the new commands. The message Process recipe variable commands stored appears. (7) Go to the Start/Continue a new process recipe procedure to start the process recipe if it is not running.

40 Document nr. : WimEin V01 Page nr. : TSC-2 (1) select the desired tube from the pull-down menu or from the Overview screen. (2) select Operations to access the operations screen. (3) Select Edit Variable Commands to open the list with available Variable Commands

41 Document nr. : WimEin V01 Page nr. : 41 (4) edit the desired process setting a. highlight the desired process setting b. press Edit to open the Edit mode c. modify to the desired process setting (5) press Updates to store the new commands (6) go to the Start/Continue a new process recipe procedure to start the process recipe if it is not running.

42 Document nr. : WimEin V01 Page nr. : Clear Alarms Visible and audible Alarms signals are generated by the DPC and DTC. The visible alarms will be presented both on the touchscreen and the TSC-2 computer(s), the audible alarms are available on the touchscreen only. Two different audible alarm signals are available: operator alert: an intermittent beep-beep-beep to alert an operator for action (press Start for example); alarm signal: a continuous beeeeeeeeeeeeep to alert for an alarm situation Required action Operator alert signals (beep-beep-beep) require the operator to press Start to have the furnace proceed to the next step in the process; Alarm situation signals (beeeeeeeeeeep) require the operator to alert the responsible person(s) immediately Touchscreen (1) touch the touchscreen to silence the buzzer (2) read the alarm message in the bottom line of the screen (3) take the appropriate action as described in section

43 Document nr. : WimEin V01 Page nr. : TSC-2 (1) the overview screen gives an instant view of which tubes are in alarm in RED (2) select the desired tube from the pull-down menu or from the Overview screen (3) select the Alarm screen (4) read the alarm message(s) (5) take the appropriate action as described in section 4.8.1

44 Document nr. : WimEin V01 Page nr. : Rules & Regulations Tube O34A1 Atmospheric process Remarks Only metal-free processing of Si substrates. New (monitor) wafers no cleaning required. Cleaning procedure after processing on metal contaminated tools (e.g. stepper, barrel, dry-etcher, microscope, etc.): O34A3 (1) Cintilio: recipe FZHClplus (2) 15 Fuming / 15 boiling nitric acid. (3) 15 Piranha (4) SSEC, piranha based recipe process both sides. Processing of both metal and non-metal wafers. Processing of different substrates / materials (e.g.) glass allowed. O35B2 For processing of organical materials consult the tool-owner. In principle organical materials are allowed as long as the temperature step does not lead to contamination of the furnace tube or deposition on the furnace tube. Only metal-free processing of Si substrates. New (monitor) wafers no cleaning required. Cleaning procedure after processing on metal contaminated tools (e.g. stepper, barrel, dry-etcher, microscope, etc.): O36E2 (1) Cintilio: recipe FZHClplus (2) 15 Fuming / 15 boiling nitric acid. (3) 15 Piranha (4) SSEC, piranha based recipe process both sides. Only metal-free processing of Si substrates. New (monitor) wafers no cleaning required. Cleaning procedure after processing on metal contaminated tools (e.g. stepper, barrel, dry-etcher, microscope, etc.): (1) Cintilio: recipe FZHClplus (2) 15 Fuming / 15 boiling nitric acid. (3) 15 Piranha (4) SSEC, piranha based recipe process both sides.

45 Document nr. : WimEin V01 Page nr. : 45 O37C1 Only metal-free processing of Si substrates. New (monitor) wafers no cleaning required. Cleaning procedure after processing on metal contaminated tools (e.g. stepper, barrel, dry-etcher, microscope, etc.): O37C2 (1) Cintilio: recipe FZHClplus (2) 15 Fuming / 15 boiling nitric acid. (3) 15 Piranha (4) SSEC, piranha based recipe process both sides. Oxidation / anneal furnace tube for processing of e.g. MEMS devices. For this reason it s allowed to use a different cleaning procedure in consultation with the toolowner. Only metal-free processing of Si substrates. New (monitor) wafers no cleaning required. Cleaning procedure after processing on metal contaminated tools (e.g. stepper, barrel, dry-etcher, microscope, etc.): O38D2 (1) Cintilio: recipe FZHClplus (2) 15 Fuming / 15 boiling nitric acid. (3) 15 Piranha (4) SSEC, piranha based recipe process both sides. Metal alloy furnace tube. Standard IC metals: Ti, TiW, Ti(N), Ta, Al, Al(Si) and Pt O38D3 Cleaning procedure: (1) O2 plasma (2) Fuming nitric acid (3) EKC Metal alloy furnace tube. For non standard IC metals. Cleaning procedure: (1) O2 plasma (2) Fuming nitric acid (3) EKC

46 Document nr. : WimEin V01 Page nr. : 46 Tube O34A3 O35B3 O37C3 Atmospheric process Remarks Only metal-free processing of standard Si substrates (100, 150 and 200 mm). As we don t have seperate LPCVD tubes for processing of non standard substrates and / or contaminated substrates exceptions can be made but only in consultation with the toolowner. New (monitor) wafers no cleaning required. Cleaning procedure after processing on metal contaminated tools (e.g. stepper, barrel, dry-etcher, microscope, etc.): (1) Cintilio: recipe FZHClplus (2) 15 Fuming / 15 boiling nitric acid. (3) 15 Piranha (4) SSEC, piranha based recipe process both sides. 8. Instruction and test Not applicable.