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:
Feb. 26, 2002
Filed:
Jun. 24, 1997
Applicant:
Inventors:
Joe G. Hoffman, Cardiff, CA (US);
R. Scot Clark, Fallbrook, CA (US);
Assignee:
Air Liquide America Corporation, Houston, TX (US);
Primary Examiner:
Int. Cl.
CPC ...
C01C 1/16 ; C01B 7/19 ;
U.S. Cl.
CPC ...
C01C 1/16 ; C01B 7/19 ;
Abstract
Provided is a novel method and system for preparing ultra-high-purity buffered-hydrofluoric acid or ammonium fluoride controlled concentration The method comprises bubbling purified ammonia vapor into ultra-pure hydrofluoric acid. The inventive method and system can be used as an on-site subsystem in a semiconductor device fabrication facility for supplying the buffered-hydrofluoric acid and ammonium fluoride to points of use in the semiconductor device fabrication facility.