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. 24, 2006
Filed:
Aug. 04, 2004
Leping LI, Poughkeepsie, NY (US);
Steven G. Barbee, Amenia, NY (US);
Leping Li, Poughkeepsie, NY (US);
Steven G. Barbee, Amenia, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Improved endpoint detection is obtained for wet etch and/or other chemical processes involving in situ measurement of bath impedance. The endpoint detection uses a measurement apparatus having a measurement circuit with a capacitor designed to alter the phase angle of the circuit. The capacitor is preferably a variable capacitor which is used to set the initial phase angle of the measurement circuit to about zero. The methods using the improved detection enable etch to be more precisely controlled even under conditions where noise would otherwise adversely impact determination of the endpoint.