AVS 50th International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS+MM-MoA

Paper PS+MM-MoA8
Si, SiO@sub 2@ Feature Etching for MEMS Fabrication: A Combined Simulator Coupling Local Transport, Surface Etch, and Profile Evolution Models

Monday, November 3, 2003, 4:20 pm, Room 315

Session: MEMS Etching
Presenter: G. Kokkoris, National Center for Scientific Research (NCSR) "Demokritos", Greece
Authors: G. Kokkoris, National Center for Scientific Research (NCSR) "Demokritos", Greece
C. Boukouras, National Center for Scientific Research (NCSR) "Demokritos", Greece
A. Tserepi, National Center for Scientific Research (NCSR) "Demokritos", Greece
A.G. Boudouvis, National Technical University of Athens (NTUA), Greece
E. Gogolides, National Center for Scientific Research (NCSR) "Demokritos", Greece
Correspondent: Click to Email
Profile control during feature etching is a central requirement in the manufacturing processes of microelectromechanical systems (MEMS) or microelectronics devices. Simulation of the feature profile evolution can contribute to this challenge. The purpose of this work is a complete simulator for feature etching. The goal is to predict the effect of the bulk plasma phase to the feature profile, and is accomplished through the coupling of the following component modules: 1) a local transport model: local fluxes of neutrals and ions inside features are calculated taking into account shadowing and re-emission phenomena.@footnote 1@ 2) a surface etch model: local etch rates at each elementary surface of the structure are calculated through site balances. Si, SiO@sub 2@ substrate etching models under fluorine or fluorocarbon plasmas have already been developed.@footnote 2@ 3) a profile evolution algorithm: the level set method@footnote 3@ is fed with the local etch rates and moves the feature profile. The complete simulator can be used to a) validate suggested surface models through comparison with experimental data, b) investigate and explain the influence of feature size and surface morphology on etch rates (e.g. reactive ion etching lag phenomenon@footnote 4@, effect of roughness on etch rates) and c) simulate and optimize processes such as the BOSCH process@footnote 5@ for the etching of high aspect ratio Si structures, where pulsed alternating flows of SF@sub 6@ and C@sub 4@F@sub 8@ gases are used. @FootnoteText@ @footnote 1@V. K. Singh, E. S. G. Shaqfeh, and J. P. McVittie, J. Vac. Sci. Technol. B 10, 1091 (1992).@footnote 2@E. Gogolides, P. Vauvert, G. Kokkoris, G. Turban, A. G. Boudouvis, J. Appl. Phys. 88, 5570 (2000).@footnote 3@J. A. Sethian, J. Comp. Phys. 169, 503 (2001).@footnote 4@G. Kokkoris, E. Gogolides, A. G. Boudouvis, J. Appl. Phys. 91, 2697 (2002).@footnote 5@F. Larmer, A. Schilp, German Patent DE 4241045.