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:
Aug. 16, 1988
Filed:
Feb. 26, 1987
Virinder Grewal, Ebersberg, DE;
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Abstract
A method for producing contact holes having sloped walls in intermediate oxide layers through combination of isotropic and anisotropic etching steps which are carried out by means of dry etching in a fluorine-containing plasma. The first etching step is an isotropic etching using an etching gas mixture in which the free fluorine atoms for the isotropic etching step are partially replaced by free CF.sub.3 radicals and ions for the anisotropic etching step. The last etching step is carried out anisotropically. Simultaneously, the electrode spacing in the reactor is reduced during the etching process. Sidewall angles between 60.degree. and 90.degree. can be reproduced with the method of the present invention. The method is particularly useful for the manufacture of large scale integrated semiconductor circuits.