Double Patterning Combined with Shrink Technique to Extend ArF - - PDF document

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Double Patterning Combined with Shrink Technique to Extend ArF - - PDF document

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Double Patterning Combined with Shrink Technique to Extend ArF Lithography for Contact Holes to 22nm Node and Beyond Huli b , Hao Che n, Xumou Julie t Xiangqun Miao, L ior Xu, Hyungje Woo, Chr is Be nc he r , Je n Shu, Chr is Ngai , Chr

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Double Patterning Combined with Shrink Technique to Extend ArF Lithography for Contact Holes to 22nm Node and Beyond

Julie t Xiangqun Miao, L ior Hulib, Hao Che n, Xumou Xu, Hyungje Woo, Chr is Be nc he r , Je n Shu, Chr is Ngai , Chr istophe r Bor stb Applie d Mate r ials

bColle ge of Nanosc ale Sc ie nc e and E

ngine e r ing of the Unive r sity at Albany

6924-9 SPIE Advanced Lithography 2008 External Use

Outline

  • 1. Introduction
  • 2. Double Patterning Dry ArF Lithography Combined

with Shrink Process with Shrink Process

  • 3. Double Patterning Immersion ArF lithography

Combined with Shrink Technique

  • 4. Summary

6924-9 SPIE Advanced Lithography 2008 External Use

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Lithography becomes much more challenging when CD shrinks to 22nm node and beyond. Since EUV is not ready, double patterning combined with Resolution Enhancement Technology (RET) such as shrink technique seems to be the most possible solution.

1. Introduction

Last year, we published the best resolution of 50nm contact holes at 100nm pitch using double patterning dry ArF lithography with SAFIER shrink. To improve the contact hole resolution, we further extend our dry ArF lithography capability using ASML XT1400EX at Applied Materials. We developed immersion ArF double patterning process using ASML XT1700i- P at CNSE combined with SAFIER shrink and etch at Applied Materials.

6924-9 SPIE Advanced Lithography 2008 External Use Coat/Expose/Develop SAFIER Coat SAFIER Bake SAFIER Rinse

SAFIER (Shrink Assist Film for Enhanced Resolution) Process

Outline

  • 1. Introduction
  • 2. Double Patterning Dry ArF Lithography Combined

with Shrink Process with Shrink Process

  • 3. Double Patterning Immersion ArF lithography

Combined with Shrink Technique

  • 4. Summary

6924-9 SPIE Advanced Lithography 2008 External Use

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  • 2. Double Patterning Dry ArF Lithography

2.1. DOF window for dry ArF lithography combined with Shrink

6924-9 SPIE Advanced Lithography 2008 External Use

  • DOF is > 0.15μm for targeting contact holes > 50nm.
  • Images show good profile through focus window for 45nm contact holes.
  • 2. Double Patterning Dry ArF Lithography

2.2. CD trends after 1st HM litho & shrink, and after etch

6924-9 SPIE Advanced Lithography 2008 External Use

For both 40 and 50nm targeting contact holes:

  • DICD and FICD show stable trends.
  • Etch bias is about -10nm.
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  • 2. Double Patterning Dry ArF Lithography

2.3. Schematic Double Patterning Flow

Schematic diagrams illustrate double patterning to form 40nm HP.

6924-9 SPIE Advanced Lithography 2008 External Use

  • 2. Double Patterning Dry ArF Lithography

2.3. Schematic Double Patterning Flow and actual wafer images

Schematic diagrams illustrate double patterning to form 40nm HP.

6924-9 SPIE Advanced Lithography 2008 External Use

Wafer images demonstrate double patterning to form 45nm HP.

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  • 2. Double Patterning Dry ArF Lithography

2.4. Contact holes at different resolution using two HM schemes

6924-9 SPIE Advanced Lithography 2008 External Use

  • Wafers with different resolution can be achieved by applying different X and

Y shift at 2nd HM litho step.

  • Both TiN and a-Si worked well as HM in the double patterning schemes.
  • Overlay is a challenge for DP process and it needs further improvements.
  • 2. Double Patterning Dry ArF Lithography

2.5. Contact profile at 37 and 40nm half pitches using TiN HM

40nm @ 73nm pitch 40nm @ 80nm pitch

37nm Half Pitch 146nm pitch 73nm pitch after DP 40nm Half Pitch 160nm pitch 80nm pitch after DP

6924-9 SPIE Advanced Lithography 2008 External Use

  • The best resolution of 37nm half pitch (HP) contact holes is achievable

by using more aggressive illumination. However, the illumination will not be in favor to print many pitches including isolated contact holes.

  • 40nm HP seems to be the most reasonable resolution for contact holes

from dry ArF double patterning process.

146nm pitch 73nm pitch after DP 160nm pitch 80nm pitch after DP

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Outline

  • 1. Introduction
  • 2. Double Patterning Dry ArF Lithography Combined

with Shrink Process with Shrink Process

  • 3. Double Patterning Immersion ArF lithography

Combined with Shrink Technique

  • 4. Summary

6924-9 SPIE Advanced Lithography 2008 External Use

  • 3. Double Patterning Immersion ArF Lithography

3.1. DOF window for immersion ArF lithography

DOF Wi d b f SAFIER Sh i k

6924-9 SPIE Advanced Lithography 2008 External Use

  • DOF > 0.15μm If pre-SAFIER contact hole CD ≥ 55nm.

DOF Window before SAFIER Shrink

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  • 3. Double Patterning Immersion ArF Lithography

3.1. DOF window for immersion ArF lithography and image after SAFIER

DOF Wi d b f SAFIER Sh i k 25nm holes after SAFIER shrink

6924-9 SPIE Advanced Lithography 2008 External Use

  • DOF > 0.15μm If pre-SAFIER contact hole CD ≥ 55nm.
  • Established SAFIER condition for immersion litho processed wafers.
  • 25nm contact holes at 130nm pitch after SAFIER show good profile.

DOF Window before SAFIER Shrink 25nm holes after SAFIER shrink

  • 3. Double Patterning Immersion ArF Lithography

3.2. DOF and contact hole profile before and after SAFIER shrink

  • DOF window remains similar before and

after SAFIER shrink.

  • DOF > 0.15μm for 30nm holes after

SAFIER shrink SAFIER shrink.

  • 30nm contact holes show good profile

through defocus positions.

6924-9 SPIE Advanced Lithography 2008 External Use

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  • 3. Double Patterning Immersion ArF Lithography

3.3. Contact holes at different double patterning steps using a-Si HM

6924-9 SPIE Advanced Lithography 2008 External Use

  • The images demonstrate Immersion DP process capability of printing

22nm Contact holes at 64nm pitch.

Outline

  • 1. Introduction
  • 2. Double Patterning Dry ArF Lithography Combined

with Shrink Process with Shrink Process

  • 3. Double Patterning Immersion ArF lithography

Combined with Shrink Technique

  • 4. Summary

6924-9 SPIE Advanced Lithography 2008 External Use

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  • 4. Summary
  • We have developed the double patterning (DP) processes using

both dry and immersion ArF lithography combined with SAFIER shrink technique.

  • We created double patterning schemes using two hard mask

materials, i.e. TiN and a-Si.

  • We successfully achieved the contact hole resolution of 40nm at

pitch of 80nm using dry ArF DP process.

  • We demonstrated the printability of 22nm contact holes at pitch
  • f 64nm using immersion ArF DP process.
  • Etching small contact holes for 22nm node and beyond is very
  • challenging. It needs additional development effort.

6924-9 SPIE Advanced Lithography 2008 External Use

g g p

  • Improvements on overlay and work on CD uniformity will be

continued.

ACKNOLEDGEMENTS

  • We would like to thank L

iyan Miao and Ping Xu for thin film de position, Han Cho for some he lp on T iN HM e tc h, Nic olas Gani for sugge stion on a Si e tc h and the suppor t fr

  • m ope r

ation for sugge stion on a-Si e tc h, and the suppor t fr

  • m ope r

ation, Maydan T e c hnology Ce nte r Gr

  • up, Applie d Mate r

ials.

  • We also like to thank Steve Hanse n, D.H. Son and Nandasir

i Samar akone fr

  • m ASMLfor the ir assistanc e on some illumination

simulation.

6924-9 SPIE Advanced Lithography 2008 External Use

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T hank you for your atte ntion!

6924-9 SPIE Advanced Lithography 2008 External Use