Inorganic Bi/In thermal resist as a high-etch-ratio patterning layer for CF4/CHF3/O2 plasma etch

Yuqiang Tu; Glenn H. Chapman; Jun Peng

doi:10.1117/12.536193

14 May 2004 Inorganic Bi/In thermal resist as a high-etch-ratio patterning layer for CF₄/CHF₃/O₂ plasma etch

Yuqiang Tu, Glenn H. Chapman, Jun Peng

Proceedings Volume 5376, Advances in Resist Technology and Processing XXI; (2004) https://doi.org/10.1117/12.536193
Event: Microlithography 2004, 2004, Santa Clara, California, United States

Abstract

Bimetallic thin films containing indium and with low eutectic points, such as Bi/In, have been found to form highly sensitive thermal resists. They can be exposed by lasers with a wide range of wavelengths and be developed by diluted RCA2 solutions. The exposed bimetallic resist Bi/In can work as an etch masking layer for alkaline-based (KOH, TMAH and EDP) “wet” Si anisotropic etching. Current research shows that it can also act as a patterning and masking layer for Si and SiO₂ plasma “dry” etch using CF₄/CHF₃. The profile of etched structures can be tuned by adding CHF₃ and other gases such as Ar, and by changing the CF₄/CHF₃ ratio. Depending on the fluorocarbon plasma etching recipe the etch rate of laser exposed Bi/In can be as low as 0.1nm/min, 500 times lower than organic photoresists. O₂ plasma ashing has little etching effect on exposed Bi/In, indicating that laser exposure is an oxidation process. Experiment result shows that single metal Indium film and bilayer Sn/In exhibit thermal resist characteristics but at higher exposure levels. They can be developed in diluted RCA2 solution and used as etch mask layers for Si anisotropic etch and plasma etch.

Citation Download Citation

Yuqiang Tu, Glenn H. Chapman, and Jun Peng "Inorganic Bi/In thermal resist as a high-etch-ratio patterning layer for CF₄/CHF₃/O₂ plasma etch", Proc. SPIE 5376, Advances in Resist Technology and Processing XXI, (14 May 2004); https://doi.org/10.1117/12.536193

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