The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 17, 1992
Filed:
Dec. 28, 1990
Kabushiki Kaisha Toyota Chuo Kenkyusho, Aichi, JP;
Abstract
A semiconductor pressure sensor having a diaphragm formed over the surface of a semiconductor substrate by thin film forming technique is provided. The sensor comprises: a sacrificial film including a vanishable portion covering a pressure receiving region on the major surface of the semiconductor substrate and a diaphragm support portion covering the periphery of the pressure receiving region, the vanishable portion having an isotropic etching property along the pressure receiving region and the diaphragm support portion having an etching-resistant property; an insulation diaphragm film having an etching-resistant property formed on the major surface of the semiconductor substrate over the sacrificial film; at least one etching solution inlet port formed through the insulation diaphragm film to reach the vanishable portion of the sacrificial film; a reference pressure chamber formed by etching and removing at least the vanishable portion of the sacrificial film with an etching solution poured through the inlet port; and at least one strain gauge formed on the insulation diaphragm film in place at the pressure receiving region. The peripheral region of the movable diaphragm can be formed into a flat configuration without any stepped structure. Thus, the semiconductor pressure snesor has an improved characteristics.