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:
Apr. 04, 2000
Filed:
May. 21, 1998
Applicant:
Inventors:
Theresia Bauer, Burgkirchen, DE;
Susanne Weizbauer, Rosenheim, DE;
Hanns Wochner, Burghausen, DE;
Alfred Bergler, Neuotting, DE;
Assignee:
Wacker Siltronic Gesellschaft Fur Halbleitermaterialien AG, Burghausen, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
438745 ; 438753 ; 438974 ; 252 793 ;
Abstract
A process is taught for etching semiconductor wafers with an etching mixture comprising nitric and hydrofluoric acids and optionally a surfactant. To this mixture are added either more hydrofluoric acid, or more hydrofluoric and nitric acids, with the added acids having concentrations of at least 70% by weight. The use of concentrated acids reduces the loss of substrate material and extends etching bath life.