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:
Aug. 30, 2005
Filed:
Nov. 04, 2002
Kevin Weaver, San Jose, CA (US);
Zachary Joshua Gemmill, Mountain View, CA (US);
Steven Jacobson, Dublin, CA (US);
Kevin Weaver, San Jose, CA (US);
Zachary Joshua Gemmill, Mountain View, CA (US);
Steven Jacobson, Dublin, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
The thickness of a semiconductor wafer is non-destructively measured using infrared (IR) microscopy. The wafer is placed on a stage. A distance between the stage and a detector is then varied so that a first image of the wafer is focused on the detector. When focused, a first separation distance is measured. The distance between the stage and the detector is again varied so that a second image is focused on the detector. When again focused, a second separation distance is measured. The difference between the first and second separation distances is then determined and multiplied by the refractive index of light in silicon.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile