qna l6 s project aa cmp oxide range reduction (oct 08)

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  • 1. Lean Six Sigma Project:CMP Oxide Film ThicknessUniformity Improvement y pFINAL REPORTOctober 2008Norbert GloserQimonda Operational Excellence Qimonda confidential

2. ContentsD M A I C1) Introduction to CMP Basics2) DMAIC Phase Summary ) y Define Phase Measure Phase Analyze Ph A l Phase Improve Phase Control Phase3) Project Summary4) Appendix DMAIC Tool Summary Tollgate Approvals Control Plan Transition Plan Glossary 3. CMP Basic 1: What is CMP?D M A I CFunctional principle of CMPThe process uses an abrasive andcorrosive slurry in conjunction with apolishing pad.Pad and wafer are pressed together by adynamic polishing head and held in placeby a plastic retaining ring.The dynamic polishing head is rotatedwith different axes of rotation.This removes material and tends to evenout any irregular topography, making they g p g p y, gwafer flat or planar. 4. CMP Basic 2: How does the 4-Zone Polishing Head work?DMAI C Each Polishing Head has 4 zones to control Uniformity through varying air pressures: CAP: Center Air Pressure(0mm - 30mm) RAP: Ripple Air Pressure(31mm - 64mm) OAP: Outer Air Pressure (65mm - 84mm) EAP: Edge Air Pressure(85mm 100mm) The Polishing Chamber Pressure (PCP) is used to adjust the overall polishing pressureof the head and normally held constant. 5. DMAIC MethodologyD M A I CDEFINE: P j t scope, purpose and customer requirementsProjectdt i tMEASURE: Baseline of underlying p S y g processANALYZE: Collect data for trend, root causes, key input driversIMPROVE: Current process by improving input variation (DOE)CONTROL: Inputs discovered in previous steps 6. CMP Oxide Film ThicknessUniformity Improvement D M AICBusiness Case: Opportunity: yThe non-uniformity of the a CMP Oxide process contributesQimonda not satisfied with 80nm technology yield from QR2.extensively to the yield loss at the Qimonda Richmond 200mmOpportunity exists to improve QR2 80nm yield by improvingPlant (QR2). uniformity in the AA module.The device yield loss (non-functional chips) is 2.3%.The CMP AA Oxide process is a main contributor to the these yieldThe reduction of CMP non-uniformity at this step will results in detractors.$4.1 Mio. Savings per year.$4 1 Mi S iGoal:Scope:Reduce AA Post Oxide within wafer range (lot average) from In scope: AA Oxide uniformity, Ebara FREX toolset550A to 320A by September 2008 (based on comparison toQimonda Richmond 300m QR3 bench mark) on T80 product.Not in scope: 110nm, AA defectivity, other CMP processes, AMAT MIRRA toolsetRoadmap: Core Team: Role Name 6S BBNorbert Gloser QR2 CMP PE Mark Collins QR2 CMP PE Kam Hettiaratchi QR3 CMP PE Andreas Fischer QR2 CMP EE Nishant Chadha PI Han Park 7. Project Selection VOC and financial returnD M AIC ROCE EBITTAX Capitalemployed RevenueCost ASP Volume TtM Prod.Qual. Fab WSPW Financial return: Output- Approx. 4.1 Mio revenue per year Assumptions: A ti R&D time- increase in YBS3 of 2.3%CTFab YieldWafer Yield line(additional 11 512MB chips per wafer) - ASP of $1.65/chipAA divots- 5000 WSPW - Yield improvement on allCMP AA 80nm products uniformity 8. Project DefinitionD MAI CProblem Statement: Metrics: What: Yield loss due to high AA Post Primary Metric:Oxide within Wafer Range AA Post Oxide within Wafer Range Where: CMP AA TEOS in QR2 Secondary Metrics: When: Since QR2 T80 start upstart-up Yield Problem indicator: Yield loss, Physical Consequential Metrics:Failure Analysis, QR3 benchmark results Cycle Time, Cost of Ownership (y, p (CoO) )Financial Metric:Objective Statement: Yield gain: 2.3% Currently: OxRgMean = 544A Chi output: 55 000 (Chip t t 55,000 (per week) k) E titlEntitlement: O R Mean = 230At OxRg(Est. depending on weekly wafer starts(QR3 benchmark)and product mix) Goal: OxRgMean = 320A T t l ROI: $4 1 Mi (Total ROI $4.1 Mio. (per year) )(70% of gap t bf to benchmark) h k)(Est. depending on chip price) 9. Project Team D M A I C 10. Define Phase Summary & LSS Tools usedDM A ICSummary: Tools/methodologies used:- Used VOC to select project - Voice of customer (VOC)- Defined problem statement- Defined AA Post Oxide within WaferRang as primary metric- Defined secondary andconsequential metrics- Provided currently capability andcompared it to benchmark- Set goal for primary metric based on70% gap- Identified ROI of $4.1 Mio. Per y$ year- Selected team members 11. Process Map:Macro MapD M A I C 12. Bench Marking andProcess Capability DM A ICQR2QR3 (benchmark)OXRG meanMean(Range(Post Ox))70% of gap to QR3 performance1000 1000 900900=> target: 320Ag 800800 700700Remark:320A is the goal for mean value and not the Upper Spec Limit. 600600As there is no spec limit existing we used the goal for the capability calculation. 500500 400400Process Capability of OXRG P7RSLTX 300300 200200 USL 100100P rocess D ata Within 00LS L*Ov erall Target* USL 320 P otential (Within) C apability QuantilesQuantiles S ample M ean 585.894 Z.Bench-2.45100.0% maximum864.61 100.0% maximum376.17S ample N 305 Z.LS L *99.5% 864.61 99.5% 376.17S tD ev (Within)108.412 Z.U S L-2.4597.5% 790.87 97.5% 362.17S tD ev (O v erall) 174.87C pk -0.8290.0% 698.74 90.0% 302.03 O v erall C apability75.0% quartile602.62 75.0% quartile275.67Z.Bench-1.5250.0% median531.53 50.0% median221.50 Less thanZ.LS L *25.0% quartile457.22 25.0% quartile199.83 2% Z.U S L-1.52 P pk -0.5110.0% 410.36 10.0% 161.78 of lots meet C pm *2.5%376.45 2.5%124.57320A target0.5%361.14 0.5% 96.170.0% minimum361.14 0.0% minimum 96.17 MomentsMomentsMean 543.76823 Mean 230.39178300450600750 9001050 1200Std Dev108.65107 Std Dev54.104032O bserv ed P erformance E xp. Within P erformanceE xp. O v erall P erformanceStd Err Mean 10.087998 Std Err Mean 6.4209673 % < LS L * % < LS L *% < LS L *upper 95% Mean 563.75062 upper 95% Mean 243.198 % > U S L 98.03% > U S L 99.29 % > U S L 93.58lower 95% Mean 523.78585 lower 95% Mean 217.58557 % Total98.03 % Total99.29% Total93.58 May-08 dataN116 N 71 13. C (non)unifor I A A C MP mity AC&E Diagram - AA CMP Uniformity Improvement M Personnel Tool capabilityManual ops PMs DPersonnell Machines e m fg dad stM at e Heju rAdpepe onstyP siontE dat P rat ebr eWarm-up wfrsID ne er ralil SW on PP t iodu Product type op m bbC iConsum lifetime cle D C hersHead rebuild seNu Sc ve eIncomingpProcess Control Rework tyAutomationl ConditionerooT ProceduresHead ySlurry ta PPID Pad da 2R Methods HMaterialM t i l Tre RuEP suE r ib IDP ealFMist ST HD tr o ti di i br MoneDAaum on T vnem AX atC s itocC e roo t io ioMLO ld imD tionZon Gt e SE ooL cta Atr aanTen OCPPFil R e Sp tsFishbone Diagram: s Rr op i ie rr le T n peLim Ca yPM ab rybT T u r p- Su OPSlmUniformity = F(X) Ex-situ a m R Ra ProritiesIn-situProductal WorkloadMeasurements ntio Env ironmentt aQual ovnc NFu )tlden(Yie ric nnm met t io igm Y mp laAlr a LY re PaP raor n C odt ioPr ca c ica toLo EPLeMs FMte A siof f A A # KL Ls zy oln toueing ofeq pl Fr m# Sa 14. ScoreZonePres024 68 1012 1416 1820 2224 2628 3032 3436 3840 su res H Novead a type RG 2R rooR ve H et sDefine Xs ea . R d in C re g on bu di i tio ldniRa ngR mpam -p- up do wn STI EPareto C&E Matrix:Ta D E P bl PTC eS Harrie pe r S edpeC ed on tr ol TopLi m Lo itscaPotential XtionC&E ranking SubPCO PCAPSE s LO A X Sl A H ur DDry PCFlow on su m TypC life eal tim ib erMD atiistr onsC ib uo n t io di nt io neAO rth erI0.00%5.00%10.00% 15.00%20 00% 25.00%30.00% 35.00%40.00% 45.00%50.00% 55.00%60.00%70.00% 75.00%80.00% 85.00%90.00% 95.00%20.00% 65 00% 65.00%100.00% % cumC 15. Measure Phase Summary & LSS Tools used DMA I CSummary:Tools/methodologies used:- Mapped material flow through AA - Process Flow DiagramTEOS CMP area - Data Collection- Collected data for current process- Capability Analysisand bd benchmark hk- Benchmarking- Goal is 70% gap: 320A- C&E Fishbone- Current capability is less than 2%- C&E Matrix- Used 6M Fishbone Diagram to- Pareto Diagramidentify inputs to uniformity/range- Potential XsXs- Surveyed CMP experts to createC&E matrix- Identified TOP5 inputs using ParetopgDiagram 16. TOP 5 inputs & proposed changes X=f(x)DMAIC C&E1st level Root Capital Score Proposed ChangesResources Category Category Causerequired Determine preferable ZPMethodRecipeZone Pressures38 adjustments to minimize CMP CMP PE / R2R NO non-uniformity Analyze process capabilityMachine Tool capability Head type 36 CMP PE NO between Gen I and Gen II tools Evaluate usage of Nova in-situ In-situ Nova / CMP PE /MeaurementNova36 film thickness measurment tools YES MeasurementsCMP EE on Ebara FREX 200 toolsets Develop methodology to IT / EbEbara / CMP automatically adjust tool para-MethodAutomationRun-2-Run 33 PE / CMP EE / YES meters to minimize CMP non- R2R uniformity Evaluate X-Y grooved p usedg padMaterialM t i l PadP d GroovesG 32 CMP PE NO at QR3 17. Radial Profiles: 12-pt. vs. 85-pt.D MA I C Post Oxide - Radial Profiles 3300Local 3200Underpolish 3100 3000Post Oxide thickness [A] 2900 Center AirbagRipple AirbagOuter AirbagEdge AirbagBoth defects 2800Yield KillersYi ld Kill 2700 2600 2500 2400 85-pt. 12-pt. thickness measurement are usedLocal12-pt. p in production for capacity reasonsreasons.Overpolish 23000 510 15 2025 30 35 40 45 5055 60 65 70 7580 85 90 95 100Radius [mm] 18. Tool capability Improvement: Head styleDMA ICOneway Analysis of WIW OXRG By Head 900 Observation: 800 Gen I head (CMP 22) has in average a 70A(CMP_22) 700 higher range than Gen II head (CMP_23/26)WIW OXRG 600 500 Conclusion: Two options for improvement:W 400 1. Use only Gen II tools and use Gen I only 300as backup only when WIP is high 200(tool dedication per dispatch software GEN IGEN IIEach Pair and per SOP).Students t0.05 2. Upgrade CMP_22 to Gen II head Headcapability (approx $140K).Missing Rows 9(To be implemented after capital Quantilesfreeze lifted). Level Minimum 10%25%Median 75%90% Maximum GEN I 256.492 332.5238 383.1553435.597 488.5748 589.5398 845.6733 Improvements: GEN II195.194 265.6953