A detailed investigation and explanation of the appearance of different undercut profiles in KOH and TMAH

Pal, Prem and Haldar, S and Singh, S S and Ashok, A and Yan, X and Sato, K (2014) A detailed investigation and explanation of the appearance of different undercut profiles in KOH and TMAH. Journal of Micromechanics and Microengineering, 24 (9). ISSN 0960-1317

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In wet anisotropic etching, the etched profile of undercut convex corners depends on the type of etchant. A considerable amount of research has been carried out to explain this convex corner undercutting and to identify the orientation of undercut planes. However, it is not clearly understood why differently shaped undercut fronts appear with different etchants. Moreover, there has been no descriptive explanation regarding the distinct shape of the undercut convex corner in both KOH and TMAH. In this work, corner undercutting on the surface of a Si{100} wafer is thoroughly investigated. The undercutting behavior is examined for two different kinds of etchants (KOH and TMAH). The study is performed by analyzing the etching characteristics of different kinds of convex corners on the mask patterns. One type of corner in the mask design is formed by <110 > directions, while other types are formed by the intersection of different directions, which shapes the undercut convex corner profile. Furthermore, the appearance of etchant-dependent beveled directions at convex corners is clearly explained using the contour plot of the etch-rate data of a silicon hemisphere.

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IITH Creators:
IITH CreatorsORCiD
Item Type: Article
Uncontrolled Keywords: convex and concave corners; KOH; MEMS; silicon; TMAH; wet anisotropic etching
Subjects: Physics
Divisions: Department of Physics
Depositing User: Team Library
Date Deposited: 02 Dec 2014 06:58
Last Modified: 10 Nov 2017 05:57
URI: http://raiith.iith.ac.in/id/eprint/1105
Publisher URL: https://doi.org/10.1088/0960-1317/24/9/095026
OA policy: http://www.sherpa.ac.uk/romeo/issn/0960-1317/
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