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Proceedings Paper

Optimization of plasma etching of SiO2 as hard mask for HgCdTe dry etching
Author(s): Yiyu Chen; Zhenhua Ye; Changhong Sun; Shan Zhang; Wen Xin; Xiaoning Hu; Ruijun Ding; Li He
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Paper Abstract

HgCdTe is one of the dominating materials for infrared detection. To pattern this material, our group has proven the feasibility of SiO2 as a hard mask in dry etching process. In recent years, the SiO2 mask patterned by plasma with an auto-stopping layer of ZnS sandwiched between HgCdTe and SiO2 has been developed by our group. In this article, we will report the optimization of SiO2 etching on HgCdTe. The etching of SiO2 is very mature nowadays. Multiple etching recipes with deferent gas mixtures can be used. We utilized a recipe containing Ar and CHF3. With strictly controlled photolithography, the high aspect-ratio profile of SiO2 was firstly achieved on GaAs substrate. However, the same recipe could not work well on MCT because of the low thermal conductivity of HgCdTe and CdTe, resulting in overheated and deteriorated photoresist. By decreasing the temperature, the photoresist maintained its good profile. A starting table temperature around -5°C worked well enough. And a steep profile was achieved as checked by the SEM. Further decreasing of temperature introduced profile with beveled corner. The process window of the temperature is around 10°C. Reproducibility and uniformity were also confirmed for this recipe.

Paper Details

Date Published: 1 November 2016
PDF: 5 pages
Proc. SPIE 10157, Infrared Technology and Applications, and Robot Sensing and Advanced Control, 101573L (1 November 2016); doi: 10.1117/12.2247502
Show Author Affiliations
Yiyu Chen, Shanghai Institute of Technical Physics (China)
Univ. of Chinese Academy of Sciences (China)
Zhenhua Ye, Shanghai Institute of Technical Physics (China)
Changhong Sun, Shanghai Institute of Technical Physics (China)
Shan Zhang, Shanghai Institute of Technical Physics (China)
Wen Xin, Shanghai Institute of Technical Physics (China)
Xiaoning Hu, Shanghai Institute of Technical Physics (China)
Ruijun Ding, Shanghai Institute of Technical Physics (China)
Li He, Shanghai Institute of Technical Physics (China)


Published in SPIE Proceedings Vol. 10157:
Infrared Technology and Applications, and Robot Sensing and Advanced Control

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