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. 03, 1998
Filed:
Jul. 01, 1996
Applicant:
Inventors:
Joe G Hoffman, Cardiff, CA (US);
R Scot Clark, Fallbrook, CA (US);
Assignee:
Startec Ventures, Inc., Fallbrook, CA (US);
Primary Examiner:
Int. Cl.
CPC ...
B08B / ;
U.S. Cl.
CPC ...
1341021 ; 134111 ; 134105 ; 134902 ; 210900 ;
Abstract
A process for preparing ultra-high-purity buffered hydrofluoric acid on-site at a semiconductor manufacturing facility (front end). Anhydrous ammonia is purified by scrubbing in a high-pH liquor, and then combined with high-purity aqueous HF which has been purified by a similar process. The generation is monitored by a density measurement to produce an acid whose pH and buffering are accurately controlled.