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Proceedings Paper

Fabrication of micromechanical structures in silicon using SF6/O2 gas mixtures
Author(s): Ashok K. Paul; Askok K. Dimri; S. Mohan
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Paper Abstract

Plasma etching has been used for the fabrication of micromechanical structures in silicon with fine feature size. In this paper, reactive ion etching (RIE) is used for micromachining applications in two steps, first for etching of SiO2 layer and then machining of silicon. The first RIE step is for the patterning of the SiO2 layer using photo-resist as mask. This process involves the use of gas mixture of CHF3 and Ar. The photo-resist is then removed in the oxygen plasma. The second step is to delineate the patterned SiO2 layer onto the silicon wafer using SF6/O2 plasma. The oxygen flow is varied from 2-10 sccm in SF6. Silicon etch rates of 195 nm/min and Si/SiO2 selectivity of 10:1 has been obtained. The process parameters such as gas flow, rf-power and etch pressure are optimized as per our reactor's configuration to have compromise for best selectivity, anisotropy, and high etch rates. A pattern transfer with nearly vertical walls is obtained for RIE based on SF6/O2/CHF3 while maintaining the substrate at low temperature.

Paper Details

Date Published: 9 November 1999
PDF: 7 pages
Proc. SPIE 3903, Indo-Russian Workshop on Micromechanical Systems, (9 November 1999); doi: 10.1117/12.369446
Show Author Affiliations
Ashok K. Paul, Central Scientific Instruments Organization (India)
Askok K. Dimri, Central Scientific Instruments Organization (India)
S. Mohan, Central Scientific Instruments Organization (India)

Published in SPIE Proceedings Vol. 3903:
Indo-Russian Workshop on Micromechanical Systems
Vladimir I. Pustovoy; Vinoy K. Jain, Editor(s)

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