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:
Mar. 30, 2004
Filed:
Apr. 12, 2001
Yang Zhao, North Andover, MA (US);
Yaping Hua, Wuxi, CN;
Memsic, Inc., Andover, MA (US);
Abstract
A method of etching a trench in a substrate using a dry plasma etch technique that allows precise control of lateral undercut. The method includes optionally forming at least one on-chip device or micro-machined structure in a surface of a silicon substrate, and covering the surface with a masking layer. A trench pattern is then imaged in or transferred to the masking layer for subsequent etching of the substrate. Upper portions of the trench are anisotropically etched in the substrate. The trench is then semi-anisotropically etched and isotropically etched in the substrate. By modifying isotropic etching time, a controlled lateral undercut can be achieved as the trench is etched vertically in the substrate.