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Wj Deposition Overview

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1. WJ APCVD Overview Steve AngererSteve Angerer 08/28/0208/28/02 2. WJ APCVD Overview  Objective:Objective: To get a better understanding of theTo get a better…
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  • 1. WJ APCVD Overview Steve AngererSteve Angerer 08/28/0208/28/02
  • 2. WJ APCVD Overview  Objective:Objective: To get a better understanding of theTo get a better understanding of the WJ APCVD systems process, qualWJ APCVD systems process, qual requirements, recognize the tool, and therequirements, recognize the tool, and the failure mechanisms to common problems.failure mechanisms to common problems.
  • 3. WJ APCVD Definition Terms  APCVDAPCVD Atmospheric pressure chemical vapor deposition was the first form of CVD to be widelyAtmospheric pressure chemical vapor deposition was the first form of CVD to be widely accepted in the manufacturing area. The advantage of APCVD is high throughput. Oneaccepted in the manufacturing area. The advantage of APCVD is high throughput. One drawback is that it is prone to generating particles in and on the films.drawback is that it is prone to generating particles in and on the films.  Butterfly ValveButterfly Valve The shape of a damper that controls flow within the tube, line or plenum. The chamberThe shape of a damper that controls flow within the tube, line or plenum. The chamber exhaust pressure is controlled by the PEV (a butterfly-shaped choke valve), and the entryexhaust pressure is controlled by the PEV (a butterfly-shaped choke valve), and the entry and exit exhaust pressures are controlled by manual butterfly-shaped valves.and exit exhaust pressures are controlled by manual butterfly-shaped valves.  Bypass PlenumsBypass Plenums Plenums around the deposition chambers, from one end of the process muffle to thePlenums around the deposition chambers, from one end of the process muffle to the other, that equalize muffle pressures without causing disruptive flows through theother, that equalize muffle pressures without causing disruptive flows through the deposition chambers. The WJ1000 has two bypass plenums: the muffle bypass and thedeposition chambers. The WJ1000 has two bypass plenums: the muffle bypass and the chamber bypass.chamber bypass.  Chamber N2Chamber N2 Chamber nitrogen flows between the outside of the IVA and the inside wall of theChamber nitrogen flows between the outside of the IVA and the inside wall of the opening in the process muffle. The flowmeters are numbered to correspond to theopening in the process muffle. The flowmeters are numbered to correspond to the individual deposition chamber. (Also called chamber purge N2)individual deposition chamber. (Also called chamber purge N2)
  • 4. WJ APCVD Definition Terms  Compact Exhaust Flow Control “CFC”Compact Exhaust Flow Control “CFC” A process exhaust system which controls process exhaust flow independently of theA process exhaust system which controls process exhaust flow independently of the powder accumulated in the process exhaust hardware. The constant exhaust mass flowpowder accumulated in the process exhaust hardware. The constant exhaust mass flow rate prolongs the life of the IVA’s and maintains wafer to wafer film thickness overrate prolongs the life of the IVA’s and maintains wafer to wafer film thickness over longer intervals than the standard systemlonger intervals than the standard system  Cooling MuffleCooling Muffle Is part of the muffle adjacent to the process muffle at the reactor unload end. TheIs part of the muffle adjacent to the process muffle at the reactor unload end. The cooling muffle removes heat from the wafers and the belt as they pass through it.cooling muffle removes heat from the wafers and the belt as they pass through it.  Curtain N2Curtain N2 Curtain nitrogen flows are a barrier between the room environment and the processCurtain nitrogen flows are a barrier between the room environment and the process muffle or etch muffle. There are curtains at the entry and exit of the muffle and beforemuffle or etch muffle. There are curtains at the entry and exit of the muffle and before and after each deposition chamber. They are usually named for their location within theand after each deposition chamber. They are usually named for their location within the muffle.muffle.
  • 5. WJ APCVD Definition Terms  Deposition ChamberDeposition Chamber 1) The space within the process muffle where deposition occurs. There are four1) The space within the process muffle where deposition occurs. There are four deposition chambers, bounded by the muffle floor on the bottom, the injector on the top,deposition chambers, bounded by the muffle floor on the bottom, the injector on the top, and the muffle and baffles on both sides.and the muffle and baffles on both sides. 2) One of four openings into the process muffle into which an injector vent assembly is2) One of four openings into the process muffle into which an injector vent assembly is placed.placed. 3) A term used inaccurately to refer to the IVA, the process muffle, and the load and3) A term used inaccurately to refer to the IVA, the process muffle, and the load and unload baffle on both sides of a chamber.unload baffle on both sides of a chamber.  Double ContainmentDouble Containment Any two-level safe containment system for hazardous substances. Includes a secondaryAny two-level safe containment system for hazardous substances. Includes a secondary container to prevent escape of material in case the primary container fail.container to prevent escape of material in case the primary container fail.  Etch MuffleEtch Muffle A single-unit enclosure that contains the HF vapor used to clean film deposits from theA single-unit enclosure that contains the HF vapor used to clean film deposits from the convey belt. The etch muffle has two removable HF plenums, N2curtains, a strip heater,convey belt. The etch muffle has two removable HF plenums, N2curtains, a strip heater, and four exhaust ports.and four exhaust ports.  Etch muffle exhaustEtch muffle exhaust Any of four ports that remove gaseous by-products of HF+SiO2 reaction from the etchAny of four ports that remove gaseous by-products of HF+SiO2 reaction from the etch muffle. The exhausted areas are connected by flexible tubing, through restrictingmuffle. The exhausted areas are connected by flexible tubing, through restricting orifices, to the etch muffle exhaust manifold and plenum.orifices, to the etch muffle exhaust manifold and plenum.
  • 6. WJ APCVD Definition Terms  Gas Phase ReactionGas Phase Reaction Chemical Reaction between the deposition gasses in the space above the wafer’s surface.Chemical Reaction between the deposition gasses in the space above the wafer’s surface. Defects caused by gas phase reactions may include a hazy coating on the wafer, highDefects caused by gas phase reactions may include a hazy coating on the wafer, high particle counts, or thin coatings on all or part of the wafer.particle counts, or thin coatings on all or part of the wafer.  HazeHaze A measure of light scattering, defined as the ratio of scattered light to incident light. WJA measure of light scattering, defined as the ratio of scattered light to incident light. WJ uses the term to mean the scattering of light off the surface film on a wafer; the degree touses the term to mean the scattering of light off the surface film on a wafer; the degree to which a film on a wafer looks cloudy.which a film on a wafer looks cloudy.  InjectorInjector A component that distributes gas mixture. The injector receives gas mixtures from theA component that distributes gas mixture. The injector receives gas mixtures from the gas cabinet and distributes them as laminar flows into the deposition chamber, across thegas cabinet and distributes them as laminar flows into the deposition chamber, across the width of the conveyor belt. ( Injector Vent Assembly (IVA), Monoblok injector)width of the conveyor belt. ( Injector Vent Assembly (IVA), Monoblok injector)  Injector Vent AssemblyInjector Vent Assembly  Laminar FlowLaminar Flow Movement of air or gas, in which the entire body of air or gas essentially moves as aMovement of air or gas, in which the entire body of air or gas essentially moves as a sheet, with uniform velocity, along parallel lines. The narrow slots between the skirts ofsheet, with uniform velocity, along parallel lines. The narrow slots between the skirts of the injector create laminar flows of gas, which continue to the wafer surface, wherethe injector create laminar flows of gas, which continue to the wafer surface, where reaction occurs.reaction occurs.
  • 7. WJ APCVD Definition Terms  Load GapLoad Gap The distance between wafers on the conveyor belt. Load Gap is measured in inches fromThe distance between wafers on the conveyor belt. Load Gap is measured in inches from trailing edge of one wafer to the leading edge of th e next wafer. This is a major playertrailing edge of one wafer to the leading edge of th e next wafer. This is a major player for wafer uniformity.for wafer uniformity.  Metering TubeMetering Tube The tube within the shield that distributes nitrogen inside the frames. Four meteringThe tube within the shield that distributes nitrogen inside the frames. Four metering tubes are installed in the shield plates; N2 supplied by the end plate through the tubestubes are installed in the shield plates; N2 supplied by the end plate through the tubes and is uniformly distributed within the plenum.and is uniformly distributed within the plenum.  MuffleMuffle An enclosed space within which a process or other chemical or thermal activity occurs.An enclosed space within which a process or other chemical or thermal activity occurs.  PlenumPlenum A space or enclosure in which a gas is at greater-than-atmospheric pressure. There areA space or enclosure in which a gas is at greater-than-atmospheric pressure. There are two plenums on each of three plates in a parallel injector, which distribute gases evenlytwo plenums on each of three plates in a parallel injector, which distribute gases evenly to the metering slots.to the metering slots.  PowderPowder A process anomaly in which particles accumulate on a wafer surface due to a gas phaseA process anomaly in which particles accumulate on a wafer surface due to a gas phase reaction. Powder particles are usually 1-10 microns in diameter, and are visible to thereaction. Powder particles are usually 1-10 microns in diameter, and are visible to the eye. Powder collects in the system’s vent and exhaust elbows.eye. Powder collects in the system’s vent and exhaust elbows.
  • 8. WJ APCVD Definition Terms  Process MuffleProcess Muffle The enclosure within which deposition occurs. The process muffle is a long, flat tube.The enclosure within which deposition occurs. The process muffle is a long, flat tube. Open at both ends to allow the conveyor belt to transport wafers through the depositionOpen at both ends to allow the conveyor belt to transport wafers through the deposition environment. The muffle has openings at the top for IVAs.environment. The muffle has openings at the top for IVAs.  SkirtsSkirts The thin metal strips welded to the center and bottom plates of a parallel-plate injector.The thin metal strips welded to the center and bottom plates of a parallel-plate injector. The skirts create laminar flows of reactants and N2.The skirts create laminar flows of reactants and N2.  Step CoverageStep Coverage A measure of film quality that describes the evenness of deposition over a step-shapedA measure of film quality that describes the evenness of deposition over a step-shaped structure. Step coverage is evaluated by comparing film thickness on the top of a stepstructure. Step coverage is evaluated by comparing film thickness on the top of a step with that on the bottom of the step, or by comparing thickness on the side of the stepwith that on the bottom of the step, or by comparing thickness on the side of the step with that on the bottom of the step.with that on the bottom of the step.  Throttle ValveThrottle Valve  Toroidal OrificeToroidal Orifice
  • 9. WJ APCVD Process Overview  The Basic Task is to lay down a thin film of SiO2The Basic Task is to lay down a thin film of SiO2 on the component side of 8” diameter wafers.on the component side of 8” diameter wafers.  This is done in a heated, atmospheric pressureThis is done in a heated, atmospheric pressure environment isolated by exhaust ports, N2 curtain,environment isolated by exhaust ports, N2 curtain, and mechanical baffles.and mechanical baffles.  The process muffle receives a single row of 200The process muffle receives a single row of 200 mm wafers moving along a continuous conveyormm wafers moving along a continuous conveyor belt.belt.
  • 10. WJ APCVD Process Overview cont.  The wafers are isolated from outside influences,The wafers are isolated from outside influences, pre-heated, and passed through each processpre-heated, and passed through each process chamber in sequence.chamber in sequence.  Each wafer receives process vapors from reactorEach wafer receives process vapors from reactor components located outside the muffle area.components located outside the muffle area.  Liquid source chemicals flow through coaxialLiquid source chemicals flow through coaxial lines to the reactor. In the reactor, chemicals arelines to the reactor. In the reactor, chemicals are vaporized, diluted with N2, mixed together andvaporized, diluted with N2, mixed together and passed through heated lines to the reactor gaspassed through heated lines to the reactor gas cabinet, then to the injector bay where the gassescabinet, then to the injector bay where the gasses are deposited on the wafers.are deposited on the wafers.
  • 11. WJ APCVD Process Overview cont.  The wafers are moving continuously on theThe wafers are moving continuously on the conveyor belt, which also receives a thin filmconveyor belt, which also receives a thin film during APCVD deposition. To remove this film,during APCVD deposition. To remove this film, the belt is exposed continuously to acid vapors, DIthe belt is exposed continuously to acid vapors, DI water sonic agitation , air spray, and heat towater sonic agitation , air spray, and heat to remove process contaminants.remove process contaminants.  In our application for best uniformity and stepIn our application for best uniformity and step coverage the wafers receive 2 passes through thecoverage the wafers receive 2 passes through the entire process.entire process.
  • 12. WJ APCVD Process Overview cont.  The film deposited must comply with certainThe film deposited must comply with certain physical and chemical requirements in order tophysical and chemical requirements in order to be used in device fabrication:be used in device fabrication: 1.1. Uniformity of the layer.Uniformity of the layer. 2.2. Density of SiO2 molecules in the layer.Density of SiO2 molecules in the layer. 3.3. Amount and type of stress.Amount and type of stress. 4.4. Thickness of the layer.Thickness of the layer. 5.5. Surface smoothness of the layer.Surface smoothness of the layer. 6.6. Freedom of the layer from particlesFreedom of the layer from particles 7.7. Chemical purityChemical purity 8.8. Step coverage or ability of the layer to fill in gaps or trenchesStep coverage or ability of the layer to fill in gaps or trenches beneath the layer.beneath the layer.
  • 13. WJ APCVD Qualification Requirements  Equipment Start up QualificationEquipment Start up Qualification 1. Backside PC: 200001. Backside PC: 20000 2. Stress : < 300MPa2. Stress : < 300MPa 3. R.I : 1.44-1.463. R.I : 1.44-1.46 4. Shrinkage : <9% (1000 C, 30 MIN)4. Shrinkage : <9% (1000 C, 30 MIN) 5. Stability : <1% thickness change/24 hours5. Stability : <1% thickness change/24 hours 6. Etch rate : 38-50 A/min(30 min in 0.49% HF)6. Etch rate : 38-50 A/min(30 min in 0.49% HF) 7. Step coverage: 100 % covered7. Step coverage: 100 % covered 8. Metal concentration (front side): 10 *8. Metal concentration (front side): 10 * 9. Metal concentration (back side): 300 *9. Metal concentration (back side): 300 * * In unit of E10/cm2 for Cr+Fe+Ni+Cu+Zn* In unit of E10/cm2 for Cr+Fe+Ni+Cu+Zn
  • 14. WJ APCVD Qualification Requirements cont.  Pre Lot Process Qual:Pre Lot Process Qual: Spec Test ControlSpec Test Control Process Parameter Target Freq ChartProcess Parameter Target Freq Chart ------------------------------- --------- ---------- ----------------------------------------------------- --------- ---------- ---------------------- STI NSG Qual Thk (Ang) (M) 48,PM1 DQ-THSTI7KSTI NSG Qual Thk (Ang) (M) 48,PM1 DQ-THSTI7K ( 7700A Target )( 7700A Target ) STI NSG Qual Thk Range <1362 48,PM1 DQ-THSTI7KSTI NSG Qual Thk Range <1362 48,PM1 DQ-THSTI7K ( 582A Target )( 582A Target ) (Thk 1 SIGMA) 330(Thk 1 SIGMA) 330 STI Qual Dep PC's 20 48,PM1 DQ-PCSTI7KSTI Qual Dep PC's 20 48,PM1 DQ-PCSTI7K ( > 10 OOC )( > 10 OOC )  Thickness is Controlled by Process WorksThickness is Controlled by Process Works Tuning Qual then the actual thickness qual. Process Works makes anTuning Qual then the actual thickness qual. Process Works makes an adjustment to the belt speed to center in thickness target.adjustment to the belt speed to center in thickness target.
  • 15. WJ APCVD Qualification Requirements cont.  Lot / Process Control:Lot / Process Control: Spec Test ControlSpec Test Control Process Parameter Target Freq ChartProcess Parameter Target Freq Chart ------------------------------- --------- ------- ------------------------------------------------ --------- ------- ----------------- STI NSG Thk (Ang) (M) L TM-TH-STISTI NSG Thk (Ang) (M) L TM-TH-STI ( 7700A Pilot )( 7700A Pilot ) Monitored L TM -TH-STIP ( 7450A Prod )Monitored L TM -TH-STIP ( 7450A Prod ) STI NSG Thk Range <1362 L TM-TH-STISTI NSG Thk Range <1362 L TM-TH-STI ( 582A Pilot )( 582A Pilot ) (Thk 1 SIGMA) 330(Thk 1 SIGMA) 330 NSG Dep. PC's 25 L DM-PC-STINSG Dep. PC's 25 L DM-PC-STI ( > 10 OOC )( > 10 OOC )  Process Works Re-Tunes after every 4Process Works Re-Tunes after every 4thth lot to re-lot to re- center thickness.center thickness. ( Only if the tool is idle )( Only if the tool is idle )
  • 16. WJ APCVD Return Side
  • 17. WJ APCVD Facilities Side
  • 18. WJ APCVD Wafer Path
  • 19. WJ APCVD System Layout Load Unload
  • 20. WJ APCVD Injector Layout
  • 21. WJ APCVD Problems  Particles:Particles: 1.1. Exhaust too Low or unbalancedExhaust too Low or unbalanced 2. Exhaust butterfly valve (MKS) >75 degrees2. Exhaust butterfly valve (MKS) >75 degrees 3. Separator port too low3. Separator port too low 4. Injector temperature too low4. Injector temperature too low 5. Time for injector change (nitrogen shield5. Time for injector change (nitrogen shield cleaning)cleaning) 6. Deposition temperature too low6. Deposition temperature too low 7. Chemical or O3 concentration too high7. Chemical or O3 concentration too high 8. Teos bubbler temperature too low8. Teos bubbler temperature too low 9. Poor belt cleaning9. Poor belt cleaning a. Ultrasonic belt cleaner needs flushinga. Ultrasonic belt cleaner needs flushing b. HF bubbler level too lowb. HF bubbler level too low 10. Toridal orifice failure10. Toridal orifice failure 11. Incorrect gas sequence11. Incorrect gas sequence 12. Water Leak in injector base plate12. Water Leak in injector base plate 13. Wafer Cleanliness13. Wafer Cleanliness 14. Calibration of particle analyzer14. Calibration of particle analyzer 15. Fab humidity15. Fab humidity  Film InstabilityFilm Instability 1. Deposition Rate too high1. Deposition Rate too high 2. O3 concentration too low2. O3 concentration too low 3. Film too thick3. Film too thick 4. Deposition temperature too low4. Deposition temperature too low 5 Teos bubbler temperature too low5 Teos bubbler temperature too low 6. High Humidity6. High Humidity  Poor Crack ResistancePoor Crack Resistance 1. Deposi
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