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:
Jun. 04, 2002
Filed:
Mar. 30, 1999
Kenji Yokomizo, Dr Round Rock, TX (US);
Tom Williams, Dr Austin, TX (US);
Tokyo Electron Limited, Tokyo, JP;
Abstract
An etching method and an etching apparatus are provided. Silicon (Si) from surfaces semiconductor wafers W dissolves into an etching liquid E stored in a process bath . On detection of the concentration of silicon by a concentration sensor , the etching liquid E in the process bath is discharged while leaving a part of the etching liquid when the Si concentration in the etching liquid E reaches a designated concentration. After that, a new etching liquid of substantially equal to an amount of the discharged etching liquid E is supplied into the process bath and added to the etching liquid remaining in the bath . Consequently, it is possible to restrict the etching rate just after the exchange of etching liquid from rising excessively.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile