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:
Dec. 25, 2001
Filed:
Apr. 25, 2000
Steven T. Mayer, Lake Oswego, OR (US);
John B. Alexy, West Linn, OR (US);
Jinbin Feng, Tigard, OR (US);
Novellus Systems, Inc., San Jose, CA (US);
Abstract
A chemical etching system provides a mixture of sulfuric acid and hydrogen peroxide and serves as the etchant for removing residual copper from an edge bevel region of a semiconductor wafer. The etching system includes a dilution module where concentrated sulfuric acid and concentrated hydrogen peroxide are diluted to the appropriate concentrations and then stored. To reduce the likelihood that oxygen bubbles (from hydrogen peroxide decomposition) will appear in the etchant solution, stored sulfuric acid and hydrogen peroxide are mixed immediately prior to use. In this manner, the dissolved oxygen concentration in the hydrogen peroxide decreases well below the saturation level.