Copyright Fujimi Corporation 2013

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1 High and Low Selectivity Slurries for Silicon Carbonitride CMP Hooi-Sung (Brian) Kim, Fusayo Saeki, Brian Milligan, Yasuyuki Yamato, Satoru Yarita, Yuuichi Watanabe, Tomohiko Akatsuka and Anne Milller CAMP Meeting August 12 th, 2013

2 Overview Introduction to silicon carbonitride (SiCN) and its applications Surface analysis Polishing mechanism Low selectivity slurry to TEOS High selectivity slurry to TEOS Summary

3 SiCN and Applications SiCN: silicon carbide doped with nitrogen Applications for silicon carbonitride Dielectric diffusion barrier: preventing the migration of metal atom through the SiCN layer Etch-stop Passivation layer: protecting the device from scratch Preparation method PECVD

4 Effect of N Doping Level and Pad Type on SiCN Removal Rates Higher removal rates were obtained from SiCN film with higher N content Removal rate on soft pad was higher

5 Purpose of Study and Methods Develop silicon carbonitride slurries for high and low selectivity to TEOS in acidic environment Investigate the surface of SiCN film after polish with SiCN slurries Surface hydrophilicity : goniometer (contact angle) Surface elemental analysis: XPS (X-ray Photoelectron Spectroscopy) Surface roughness: SPM (Scanning Probe Microscopy) 5

6 XPS Analysis Si N Si C Si O Si N Si C Si-O bond was detected after polish: hydration of SiCN 6

7 Oxygen Content After Polish from XPS Analysis Oxygen content increased after polish 7

8 Contact Angle Measurement Contact angle measurement with goniometer shows that surface became hydrophilic after polish with slurries indicating presence of Si-OH after polish 8

9 Mechanism of SiCN polish 1. Hydration of SiCN in acidic environment SiCxNy H+ Si-OH 2. Newly hydrated layer enables mechanical removal Hydrated Si-CN layer Si-CN

10 SiCN Removal Rates in Acidic Evironment Higher removal rates were obtained from SiCN film with higher N content in acidic environment because of hydration of SiCN

11 Surface Roughness Study with SPM Before polish After polish Slurry produced good surface roughness performance

12 Low Selectivity Slurry

13 ph Dependency of SiCN Removal Rates Low ph higher SiCN removal rates Consistent with mechanism

14 Selectivity Control by Particle and Additives At low ph, TEOS removal rates can be modulated by adjusting particle and additive concentration in the slurry

15 Poly Si Suppression by Additive PolySi RR could be modulated by the addition of additive Additive protects hydrophobic PolySi surface from particle, resulting in lower PolySi RR

16 High Selectivity Slurry

17 Slurry Performance High selectivity slurry Good performance on soft pad

18 High Selectivity Slurry Performance on Soft and Hard Pads Removal rates and selectivity controlled by dilution factor: high selectivity to TEOS achievable from both soft and hard pads

19 Summary Surface analysis study confirmed hydration of SiCN SPM study confirms surface roughness reduction Developed high and low selectivity slurries for SiCN Low selectivity slurries were modulated by adjusting multiple components High selectivity slurries were modulated by dilution Slurries are capable of polishing Poly Si 19