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:
Jul. 24, 1990
Filed:
Jun. 06, 1989
Shinichi Tachi, Sayama, JP;
Kazunori Tsujimoto, Higashiyamato, JP;
Sadayuki Okudaira, Ome, JP;
Kiichiro Mukai, Hachioji, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A deep trench is formed by carrying out etching by using an etching gas free of carbon and silicon, which contains at least one member selected from the group consisting of fluorine, chlorine and bromine, while maintaining an article to be etched at such a temperature that the reaction probability between silicon and fluorine, chlorine or bromine contained in the etching gas is less than 1/10 of the reaction probability at 20.degree. C. According to this method, a deep trench having a very narrow width and a large aspect ratio, which cannot be formed according to the conventional method, can be formed very promptly with much reduced side etching.