Kss 2010- processes for film stripping

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This Presentation was given in the Knowledge Service Seminar for TSMC head quarter in 2010

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Kss 2010- processes for film stripping

  1. 1. 1Processes for Film Stripping:Implanted Photoresist and NiPt Always Thinking. Better.™ FSI Knowledge SERVICES™ Seminar Series 2010 Copyright © 2010 FSI International All Rights Reserved
  2. 2. 2Outline • HT SPM Chemistry Theory • Film Removal Mechanism – Ion implanted Photoresist – Post anneal residual NiPt metal • Optimize the process in reaction chamber • Application Result – Ion implanted Photoresist – Post anneal residual NiPt metal • Summary FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  3. 3. 3High Temp. boost Chemical (SPM) Reactivity Main application areas are 1. FEOL polymer removal after plasma etch-ash / ion implant 2. MOL metal selective etch for silicide formation (spontaneous) H2SO4 + H2O2 H2SO5 + H2O (18 kcal/mol) (51 kcal/mol) (36 kcal/mol) 2HO• HSO4• + HO• H2O + ½O2 Higher temperature Half Cell Oxidation Reactions More oxidizing power HSO5- + 2H+ + 2e- HSO4- + H2O 1.44V H2O2 + 2H+ + 2e- H2O 1.78V HSO4• + H+ + e- H2SO4 2.60V HO• + H+ + e- H2O 2.80V FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  4. 4. 4Outline • HT SPM Chemistry Theory • Film Removal Mechanism – Ion implanted Photoresist – Post anneal residual NiPt metal • Optimize the process in reaction chamber • Application Result – Ion implanted Photoresist – Post anneal residual NiPt metal • Summary FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  5. 5. 5Implanted Photoresist Ion implantation process has many variables - Species: B, P, As, Si, Ge, BF2 - Energy: < 1keV to > 1000keV - Dosage: 1x1011 to >1x1016 ions/cm2 - Normal incidence or angled cross-linked polymer layer gate gate Most challenging where cross-linked resist is bonded to wafer surface  especially at wafer edge, near EBR regionphoto source: P. Gillespie et al, Semiconductor International, October, 1999 FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  6. 6. Ion Implantation Causes 6Cross-Linking and Dehdyrogenation Pristine Resist Crust CH2 CH2 CH2 CH2 CH CH CH CH n m n m OH OR OH OH OR OR O O CH CH CH CH CH2 CH2 CH2 CH2 n m n m Figure 4. CP-MAS 13C NMR spectra of pristine resist and crust (As 40keV 1E15cm -2) [Tsvetanova et al., ECS Trans. 25(5), 187(2009)] FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  7. 7. 7High Activation Energy to Remove Crust Ashing = Gas Phase FIGURE 7.57 Relative removal rates of standard i-line photoresist and the implanted carbonized crust layer as a function of temperature for a oxygen plasma without ion bombardment. Activation energy (Ea) has been calculated from the temperature dependence of the reaction. Robert Doering and Yoshio Nishi, Handbook of Semiconductor Manufacturing Technology (CRC Press, 2008). FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  8. 8. 8Thermodynamic Considerations Species Electro-Chemical Reactive with Reactive with Potential (eV) Bulk Resist Cross-Linked Resist CH2 HO CH2 Need radicals to attack CH2 O highly cross-linked resist OH O• (only exist in ----- Y Y asher) OH• 2.80 Y Y HSO4• 2.60 Y Y O3 2.08 Y N H2O2 1.78 N N H2SO5 1.44 Y N O2 1.23 N N H2SO5 is more effective than H2O2 because sulfuric acid can both dehydrate and dissolve short chain polymer fragments FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  9. 9. 9Radicals attack cross-links, C-C, C-O, Si-O CH2 CH2 CH CH HSO4• n m or HO• OH OR HSO4• O O or HO• CH CH CH2 CH2 CH2 n m CH n HSO4• O OH OH or HO• Si Si Si silicon wafer FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  10. 10. 10Outline • HT SPM Chemistry Theory • Film Removal Mechanism – Ion implanted Photoresist – Post anneal residual NiPt metal • Optimize the process in reaction chamber • Application Result – Ion implanted Photoresist – Post anneal residual NiPt metal • Summary FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  11. 11. 11Platinum Chemical Reaction Model  Aqua regia base : • Pt + 4NO3- + 8H+  Pt(4+) +NO2+ 4H2O Passivation • Pt(4+)+6Cl- + 2H+  H2PtCl6 CorrosionVoltage Potential  Hydrochloric acid base : • Pt + 2H2O2 + 4H+  Pt(4+) + 4H2O Immunity • Pt(4+) + 6Cl- + 2H  H2PtCl6  Sulfuric acid base : Pt + H2SO4 + H2O2  Pt(OH)2++ + PtO++ + H2SO3 pH Marcel Pourbaix, Atlas of Electrochemical Equilibria, 1974 FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  12. 12. 12Low RTP1 NixSi formation behavior FIGURE 5.3 Sheet resistance versus annealing temperature measured in situ while heating Co/Si and Ni/Si films at 3◦C/s. Note that the lower resistive NiSi phase forms at considerably lower temperature than CoSi2. However, the NiSi film also degrades at lower temperature. Lih J. Chen, Silicide technology for integrated circuits, IEE 2004 FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  13. 13. Lower Anneal Temperature Address Nickel Diffusion but 13Creates New Problem in Strip Process (HCl attack) FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  14. 14. 14Outline • HT SPM Chemistry Theory • Film Removal Mechanism – Ion implanted Photoresist – Post anneal residual NiPt metal • Optimize the process in reaction chamber • Application Result – Ion implanted Photoresist – Post anneal residual NiPt metal • Summary FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  15. 15. 121°C121°C 149°C 149°C 177°C 177°C 204°C 204°C 232°C 232°C ViPR+™ (Steam-Injected SPM) Maximizes Exothermic 15 7 ° 4 ° 2° 0 ° 8 17 20 23 26 28 C C C C Energy Release and Boosts Chemical Reactivity Steam Injection enabled by Closed Chamber & Energetic Nozzle Array STEAM mix with steam 260°C 232°C 204°C FSI ViPR™ Technology On Wafer >150ºC + high reactivity 177°C enthalpy 149°C GAS Typical Single Wafer 150°C On Wafer >150ºC mix with water/H2O2 96% LIQUID 60 70 80 90 100 weight % H2SO4 Typical Wet Bench On Wafer <150ºC FSI Knowledge SERVICES™ Seminar Series 2010 149°C Copyright © 2010 FSI International All Rights Reserved Always Thinking. Better.™
  16. 16. 16Linear Spray Nozzle Array Enhances Film Removal (1) Multiple spray dispense for mixing with steam Spray bar chemical delivery provides better mixing with steam, higher local flow rate, thinner boundary layer and larger area processing (2) Entire wafer surface processed at same time Spray bar dispense provides greater and more uniform coverage than single point nozzle. Spray bar dispense provides greater and more uniform wafer temperature than point nozzle.Single Point Nozzle Linear Nozzle Array steam FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  17. 17. 17Energized Chemical Aerosol to Boost Reactivity SPM distributed evenly across wafer Reactivity enhancement N2 flow keeps fumes out 1. POU mixing to retain transient phase chemical radical 2. N2 or Steam energized chemical aerosol to • Better wet ability • Higher collision probability / Better mass transfer • Provide additional mechanical force to peel off film 3. Use linear spray bar to maximize the amount of chemical mass in surface Exhaust keeps chamber pressure slightly reaction. negative, prevents escape of fumes FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  18. 18. 18Outline • HT SPM Chemistry Theory • Film Removal Mechanism – Ion implanted Photoresist – Post anneal residual NiPt metal • Optimize the process in reaction chamber • Application Result – Ion implanted Photoresist – Post anneal residual NiPt metal • Summary FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  19. 19. 19Implanted Photoresist Removal By Hot SPMion implantation dissolution of crust lift-off dissolutioncreates cross-linked thinner sidewall + dissolution of attached“crust” on surface crust by radical of crust layer crust layerand sidewall of PR reaction by radical reaction by radical reaction + dissolution of underlying PR by direct solvation Physical force Chemical force FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  20. 20. 20FSI ORION ViPR™ Resist Strip Capability ® All Wet Resist Strip Implant Type Pre Gate LDD S/D and PAC and PLAD ViPR ViPR+ ViPR+ Implant Level Up to 1E14 up to 1E15 up to 5E15 10 keV 10 keV Dispense time 15 40 100 (sec) SPM usage 0.38 1.0 2.5 (liter/wafer) Oxide loss(Å) < 0.1 ~0.2 ~0.3 Nitride loss(Å) <0.5 <1.0 ~1.5 8-chamber 200 150 115 Thruput (wph) (includes 30 second, room temperature, SC1 step) FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  21. 21. 21Low Material Loss – Oxide and Nitride 1.2 ■ 80s, 4:1SPM + 30s RT SC1 - furnace silicon nitride 1.0 material loss (Å) 0.8 0.6 ▲ 40s, 10:1ViPR+ + 30s RT SC1 - furnace silicon nitride 0.4  80s, 4:1SPM + 30s RT SC1 - furnace silicon oxide 0.2 ∆ 40s, 10:1ViPR+ + 30s RT SC1 - furnace silicon oxide 0.0 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 measurement point (concentric circles, 1=ctr, 49=edge) (ERF 10297, ERF 10347, lab 2010_04_23) FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  22. 22. 22Outline • HT SPM Chemistry Theory • Film Removal Mechanism – Ion implanted Photoresist – Post anneal residual NiPt metal • Optimize the process in reaction chamber • Application Result – Ion implanted Photoresist – Post anneal residual NiPt metal • Summary FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  23. 23. 23NiPt selective Etch for NiPtSi formation Si Si Pt Pt Pt Si substrate HT SPM Pt : atomic weight 195 Ni : atomic weight 58.7 TiN : capping Pt Pt Pt Selective HT RTP Wet Etch SPM O H H O O + Pt + + Pt + NixSi NixSi Si Si Pt(OH)2++ PtO++ NixSi NixSi Or cluster Si substrate H H H H O O O + Pt + Pt + Pt + + + O O H H H H FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  24. 24. ViPR™ Process Enables Wide Range of Anneal 24Conditions w/o Silicide Degradation Silicide POR (HCl) Attack ViPR Presented by Stephane Zoll (ST) at KSS 2008 Seminar in Grenoble FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  25. 25. 25NiPt Selective Process Latitude 350 ViPR 90s 300 NiPt film thickness 250 200 ViPR 60s 150 100 50 0 5% 5% 5% 5% 5% 5% 10% 10% 10% 10% Pt (%) FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  26. 26. 26Outline • HT SPM Chemistry Theory • Film Removal Mechanism – Ion implanted Photoresist – Post anneal residual NiPt metal • Optimize the process in reaction chamber • Application Result – Ion implanted Photoresist – Post anneal residual NiPt metal • Summary FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved
  27. 27. 27Summary • Thermal entropy will boost the chemical reactivity for film removal and application proven • High temperature SPM will extend the same chemical for advanced CMOS manufacturing process • Proper modulation of both chemical / mechanical force will optimize the process FSI Knowledge SERVICES™ Seminar Series 2010 Always Thinking. Better.™ Copyright © 2010 FSI International All Rights Reserved

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