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Proceedings Paper

New diaphragm structure based on SiNx/SOG for flow sensor
Author(s): Yuichi Sakai; Akira Yamashita; Tsukasa Matsuura; Kazuhiko Tsutsumi
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Paper Abstract

This paper describes the new diaphragm structure using SiNx/SOG for a micro flow sensor. Its purpose is the measurement of a correct flow rate of various gases or liquids. The proposed sensor consists of sputtered SiNx/Pt/SiNx thin film diaphragm structure, which reduces thermal capacitance. The platinum film resistors detect a change of the temperature distribution on the membrane caused by forced convection. In sensors having these film structures, sputtering methods make it much easier than other film fabrication methods, such as CVD (Chemical Vapor Deposition) to control the internal stress of SiNx film in order to stretch the diaphragm tight. However, the reliability is often spoiled by the column structue of the sputtered SiNx protective film which grows on the platinum film resistors. In order to prevent the growth of the column structure, Spin-On Glass (SOG) film is introduced between platinum film resistors and sputtered SiNx protective film. Because the SOG film is an amorphous structure. SiNx films on SOG films are dense. Additionally, SOG films reduce the step height of platinum film resistors, so the step-coverage of sputtered SiNx protective film is improved.

Paper Details

Date Published: 1 September 1998
PDF: 8 pages
Proc. SPIE 3512, Materials and Device Characterization in Micromachining, (1 September 1998); doi: 10.1117/12.324058
Show Author Affiliations
Yuichi Sakai, Mitsubishi Electric Corp. (Japan)
Akira Yamashita, Mitsubishi Electric Corp. (Japan)
Tsukasa Matsuura, Mitsubishi Electric Corp. (Japan)
Kazuhiko Tsutsumi, Mitsubishi Electric Corp. (Japan)


Published in SPIE Proceedings Vol. 3512:
Materials and Device Characterization in Micromachining
Craig R. Friedrich; Yuli Vladimirsky, Editor(s)

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