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:
Oct. 26, 1993
Filed:
Nov. 21, 1991
Applicant:
Inventors:
Takayoshi Watanabe, Fujisawa, JP;
Takashi Inoue, Yokohama, JP;
Hitoshi Oka, Yokohama, JP;
Minoru Tanaka, Yokohama, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C23F / ;
U.S. Cl.
CPC ...
156653 ; 156656 ; 156657 ; 156662 ; 252 793 ;
Abstract
A resistor material having at least chromium, silicon and oxygen, Cr.SiO.sub.2, contained in electronic integrated circuits, particularly in the case of an aluminum layer being on the material, is etched with a liquid etchant composition containing 1.92 to 2.64 mol/l of hydrochloric acid, 0.26 to 0.77 mol/l of phosphoric acid, 5 to 10 mol/l hydrofluoric acid and 3.2 to 5.4 mol/l of ammonium fluoride.