EUV patterning improvement toward high-volume manufacturing

Transcription

1 P63 EUV patterning improvement toward high-volume manufacturing 2015 International Workshop on EUV Lithography Tokyo Electron Kyushu Ltd. / SPE process dept. Y. Kuwahara, K. Matsunaga, K. Nafus, S. Kawakami imec P. Foubert, A-M. Goethals

2 Introduction Extreme ultraviolet lithography (EUVL) technology is a promising candidate of semiconductor process for 18nm half pitch and beyond. It still requires fine resolution, uniform, smooth patterns and low defectivity, not only after lithography but also after the etch process. Tokyo Electron Limited and imec are continuously collaborating to develop manufacturing quality POR processes to EUV with CLEAN TRACK TM LITHIUS Pro TM Z-EUV. We evaluated defectivity at post lithography and post etch process. New rinse material and application compatible with sub 18nm patterning is performed to prevent line pattern collapse on several resist materials, because rinse material compatibility with resist is concerned. Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 2

3 Target Defect Density (defects/cm 2 ) EUVL 32nm L/S Defects after Litho Embedded Defect reduction is the Key Challenge underlayer/si micro bridge residue 1% embedded protrusion collapse Target Defect Yuhei Kuwahara/TEL Philippe Foubert /imec et. al, SPIE 2014 Defect Budget SPIE2014 underlayer/si micro bridge residue embedded protrusion collapse 1% 12% 15% 24% Bridge Embedded 1% 9% 25% 39% 45% Mar Resist-A, Mar Resist-A, July % Reduction 0.12 Resist-A, Jan Resist-A, Jan % 4% 1. Coating related 74% (UL, EM, MB, Prt) 2. Collapse 25% Coating related defects are still majority of the defectivity Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 3

4 Normalized Defectivity Baseline Defectivity Result ADI&AEI SoC/SoG/EUV Resist-B Protrusion Microbridge Embedded 3.95 AEI Defect Images ADI&AEI Common Defect Micro Bridge Micro Bridge Embedded 2.0 AEI Specific Defect Post litho (ADI) Post Etch (AEI) Protrusion Protrusion Protrusion After etch inspection is much more sensitive, post etch defect reduction need to be addressed. Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 4

5 After Etch Defect Model Resist Film Defect Resist SoG SoC Detectable at ADI Under Layer Film Defect Resist SoG SoC Un-detectable at ADI Resist SoG SoC Un-detectable at ADI Coating related defect reduction is important to after etch defect reduction Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 5

6 Coating Defect Reduction by New Technologies at TEL in-house Normalized Blanket Defect Defect Inspection : KLA2900 (KLA-Tencor) Before verification of pattern defect, executed preliminary test for coating defect reduction by new dispense system. Protrusion Protrusion Dent Embedded 81% 71% Baseline FEF New Baseline New FEF SiARC EUV EUV-Resist Resist-C Dent Embedded New Function can reduce blanket coating defect for several materials ACI defects Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 6

7 Evaluation of AEI Defect Reduction Experiment Flow Coating scheme SoC SoG Resist-B Baseline Baseline Baseline New New New ADI NXE3100 L/S HP32nm AEI Etch Resist-B SoG SoC Defect Inspection KLA2835 Defect Inspection KLA2835 Root cause of AEI defects are investigated by using coating defect reduction technologies. Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 7

8 Normalized Defect Density AEI Defect Reduction Result Embedded Microbridge Particle Protrusion % AEI Defect Images % Micro Bridge Total 97% Reduction Embedded Total 84% Reduction 0.0 baseline New baseline New post litho post etch Defectivity is drastically improved by New Function, AEI defectivity is sensitive with coating defect. Micro bridge and Embedded defect reduction is main contributor. Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 8

9 Pattern Collapse Mitigation 1% Defect Budget SPIE2014 underlayer/si micro bridge residue embedded protrusion collapse 25% 39% 9% 22% 4% r σ σ σ=6γcosθ/d (h/w) 2 h 18nm Line& Space Pattern Collapse θ D W σ;the maximum stress which works to pattern γ;surface tension of rinse h;height of pattern 18nm Line& Space Pattern Melt θ;contact angle D;Space of pattern W;Width of pattern h/w;aspect ratio N. Namatsu et. al., Appl.. Phys. Lett. 66(20), pp , (1995) Approach to tackle this challenge Surface tension reduction by introducing a New FIRM TM Material Check the resist compatibility below 20nm pattern Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 9

10 CD [nm] FIRM TM Rinse Material Evaluation 20nmHP of Resist-B Process window Dose Focus DIW Rinse Extreme TM 10 Extreme TM A Available:15 Available:20 Available: DIW DIW Ex-10 Ex-A Extreme TM A Extreme TM Dose [mj/cm^2] No collapses Unavailable pattern (collapse, no resolution, melt) smallest CD [nm] Extreme TM is a registered trademark of AZ Electronic Materials. CD from DIW [nm] LWR [nm] DIW Extreme TM Extreme TM A Extreme TM A has best smallest CD without pattern collapse. Smaller CD change from DIW process than Extreme TM 10 Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 10

11 FIRM TM Rinse Material Resist Compatibility below 20nm Pattern Half pitch / Resist DIW Extreme TM 10 Extreme TM A HP 18nm / Resist -D Dose Focus Available:16 Available:27 Available: 27 HP 17nm / Resist-E Dose Focus Available:8 Available:9 Available: 8 No collapses Unavailable pattern (collapse, no resolution, melt) Extreme TM A shows pattern collapse mitigation for Below 20nm pattern Several resist materials HP 18nm / Resist-D HP 17nm / Resist-E smallest CD [nm] CD [nm] LWR [nm] DIW Extreme TM Extreme TM A DIW Extreme TM Extreme TM A Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 11

12 Exposure Latitude(%) 18nm HP Process Window and X-section SEM with Resist-E 18nm HP Process Window CD±5% DIW Rinse Extreme TM 10 Extreme TM A Max EL 4.3% 8.9% 6.9% Max DoF 80nm 80nm 280nm Dose to Size 36.3(mJ/cm 2 ) 38.3(mJ/cm 2 ) 36.2(mJ/cm 2 ) 18nm HP X-section DIW Rinse Extreme TM 10 Extreme TM A Height:24-29nm Height:21-28nm Height:25-31nm DIW Rinse Extreme-10 Extreme-A Depth of Focus(um) Extreme TM A achieved greater process window than Extreme10 no significant impact to pattern profile and thickness Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 12

13 L16nm P36nm with Extreme TM A and Resist-E 88% 60% 20% 80% 60% 60% 60% 80% 0% 40% 0% 80% 0% 0% 0% 80% 80% 80% 60% 80% 80% 80% 80% Ave. CD 16.4nm 3sigma:1.6nm FIRM Extreme TM 10 0% 80% 80% 0% Total 532 images/wafer Collapse Standing Ratio Ave. CD 16.6nm 3sigma:0.7nm FIRM Extreme TM A Pattern collapse is completely mitigated by FIRM Extreme TM A on 16nm line pattern. Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 13

14 Conclusion Defect reduction is key for the EUV manufacturing, especially post etch defectivity. Post Etch defectivity is reduced 85% by using New Function. Pattern collapse is one of the critical issue of the EUV lithography. FIRM Extreme TM A has demonstrated greater pattern collapse mitigation and process window enhancement on even below 20nm HP pattern. In addition, FIRM Extreme TM A has great compatibility with several imec POR materials. Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 14

15 Acknowledgement The authors would like to extend their appreciation to Tokyo Electron Kyushu Ltd. SPE Process Technology department Tokyo Electron Europe Ltd. service team Tokyo Electron Miyagi Ltd. Product engineering Y. Kuwahara / Tokyo Electron Kyushu Ltd. / SPE Process Technology Dept. / Rev. 1/ 15