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. 01, 1994
Filed:
Jan. 23, 1992
Ichiro Hayashida, Kawagoe, JP;
Masahiko Kakizawa, Kawagoe, JP;
Kenichi Umekita, Kawagoe, JP;
Hiroyoshi Nawa, Kawagoe, JP;
Hisashi Muraoka, Yokohama, JP;
Wako Pure Chemical Industries, Ltd., Osaka, JP;
Purex Co., Ltd., Yokohama, JP;
Abstract
A combination of a first surface treating solution comprising an inorganic or organic alkali such as ammonia or a quaternary ammonium hydroxide, hydrogen peroxide, water and a second surface treating solution of ultra-pure water, at least one of the first and second surface treating solutions containing as a complexing agent a compound having one or more phosphonic acid groups in the molecule and showing chelating ability, or an oxidized form thereof, or polyphosphoric acid or a salt thereof, is effective for making semiconductor surfaces free from harmful metallic impurities such as Fe, Al, Zn, etc.