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. 04, 2001
Filed:
Oct. 29, 1998
Wilbur C. Krusell, Palo Alto, CA (US);
Andrew J. Nagengast, Sunnyvale, CA (US);
Anil K. Pant, Santa Clara, CA (US);
Lam Research Corporation, Fremont, CA (US);
Abstract
A technique for utilizing a sensor to monitor fluid pressure from a fluid bearing located under a polishing pad to detect a polishing end point. A sensor is located at the leading edge of a fluid bearing of a linear polisher, which is utilized to perform chemical-mechanical polishing on a semiconductor wafer. The sensor monitors the fluid pressure to detect a change in the fluid pressure during polishing, which change corresponds to a change in the shear force when the polishing transitions from one material layer to the next. In order to ensure that there is a noticeable difference in the shear force variation at the polishing end point, a slurry having a particular pH level is selected. The pH level ensures that the zeta potential changes noticeably from one material to the next, so as to induce a change in the shear force, which is detected by a change in the fluid pressure.