Proceedings of the IEEK Conference (대한전자공학회:학술대회논문집)
- 2003.07b
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- Pages.1033-1036
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- 2003
A Study on Anisotropic Etching Characteristics of Silicon in TMAH/AP Solutions and Fabrication of a Diaphragm
TMAH/AP 용액의 실리콘 이방성 식각특성 및 다이아프램 제작에 대한 연구
Abstract
In this paper, Si anisotropic etching characteristics of tetramethylammonium hydroxide (TMAH)/ ammonium persulfate (AP) solutions were investigated to realize the optimum structure of a diaphragm for the piezoresistive pressure sensor application. Due to its low toxicity and its high compatibility with the CMOS processing, TMAH was used as Si anisotropic etchants. The variations of Si etch rate on the etching temperature, TMAH concentration, and etching time were obtained. With increasing the etching temperature and decreasing TMAH concentrations, the Si etch rate is increased while a significant non-uniformity exists on the etched surface because of formation of hillocks on the <100> surface. With the addition of AP to TMAH solution, the Si etch rate is increased and an improvement in flatness on the etching front is observed. The Si etch rate is also maximized with increasing the number of addition of AP to TMAH solution per one hour. The Si square diaphragms of 20
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