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:
Jan. 11, 2000
Filed:
Mar. 03, 1998
Applicant:
Inventors:
Allison Holbrook, San Jose, CA (US);
Jiahua Huang, San Jose, CA (US);
Aaron A Fernandes, Oakdale, CA (US);
Assignee:
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C23F / ;
U.S. Cl.
CPC ...
156345 ; 34082506 ;
Abstract
Apparatus for monitoring the hydrogen peroxide concentration in a sulfuric acid bath used to remove photoresist from semiconductor wafers uses the amount of bubbles in the fluid mixture to signal the addition of hydrogen peroxide. The bubbles are directly related to the hydrogen peroxide in sulfuric acid mixture. The bubbles are sensed by a light source and photoelectric sensor connected to a threshold adjustment control which controls a metering solenoid valve to add hydrogen peroxide from a reservoir to the bath when the bubbles decrease.