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Evolution of Si Crystallographic Planes-Etching of Square and Circle Patterns in 25 wt % TMAH

Institute of Chemistry, Technology and Metallurgy-Centre of Microelectronic Technologies (IHTM-CMT), University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia
Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade, Serbia
Author to whom correspondence should be addressed.
Micromachines 2019, 10(2), 102;
Received: 20 December 2018 / Revised: 18 January 2019 / Accepted: 26 January 2019 / Published: 31 January 2019
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application)
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Squares and circles are basic patterns for most mask designs of silicon microdevices. Evolution of etched Si crystallographic planes defined by square and circle patterns in the masking layer is presented and analyzed in this paper. The sides of square patterns in the masking layer are designed along predetermined <n10> crystallographic directions. Etching of a (100) silicon substrate is performed in 25 wt % tetramethylammonium hydroxide (TMAH) water solution at the temperature of 80 °C. Additionally, this paper presents three-dimensional (3D) simulations of the profile evolution during silicon etching of designed patterns based on the level-set method. We analyzed etching of designed patterns in the shape of square and circle islands. The crystallographic planes that appear during etching of 3D structures in the experiment and simulated etching profiles are determined. A good agreement between dominant crystallographic planes through experiments and simulations is obtained. The etch rates of dominant exposed crystallographic planes are also analytically calculated. View Full-Text
Keywords: tetramethylammonium hydroxide (TMAH); wet etching; silicon; 3D simulation; level-set method tetramethylammonium hydroxide (TMAH); wet etching; silicon; 3D simulation; level-set method

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Smiljanić, M.M.; Lazić, Ž.; Radjenović, B.; Radmilović-Radjenović, M.; Jović, V. Evolution of Si Crystallographic Planes-Etching of Square and Circle Patterns in 25 wt % TMAH. Micromachines 2019, 10, 102.

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