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:
May. 28, 2002
Filed:
Nov. 16, 1999
John A. Adams, Escondido, CA (US);
Robert A. Eaton, Scottsdale, AZ (US);
John C. Ptak, Phoenix, AZ (US);
SpeedFam-IPEC Corporation, Chandler, AZ (US);
Abstract
An apparatus for optical endpoint detection of a chemical mechanical polishing process, that reduces or eliminates interference effects caused by air bubbles in chemical polishing slurries, and accumulation of polishing debris on components of the optical system. In particular, the invention provides hydrophobic light pipes and windows with polishing surfaces substantially coplanar with surrounding surfaces of polishing pads to thereby eliminate the effect of air bubbles trapped in recesses at the polishing pad surface. Moreover, hydrophobic surfaces have now been found to resist the accumulation of polished debris thereon, resulting in a reduction in loss of optical reflectance over polishing time. Accordingly, the invention provides an optical endpoint system that eliminates or reduces both the oversaturation and loss of reflectance problems of the prior art.