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.:

US 6724479 B1

PDF
Full Text
Expired
Date of Patent:
Apr. 20, 2004

Filed:

Sep. 28, 2001
Applicant:
Inventor:

Shoaib Hasan Zaidi, Poughkeepsie, NY (US);

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01B 1/100 ;
U.S. Cl.
CPC ...
G01B 1/100 ;
Abstract

A wavefront sensing tool, such as a Shack-Hartmann detector, detects alignment features in a semiconductor wafer that might otherwise be undetectable using conventional optical tools, such as a microscope. This is particularly advantageous for alignment features formed in photoresist with a height that is less than one fourth the illuminating light's wavelength. The wavefront sensing tool can be used in conjunction with conventional optical tools and a composite alignment image can be formed from the two tools. For higher sensitivity, the light reflected off the wafer can be magnified, with e.g. a telescopic lens, prior to impinging upon the wavefront sensing tool. The composite image can be generated by one or both of the tools or by a computer coupled to the tools.


Find Patent Forward Citations

Zaidi, Shoaib. (2004). Method for overlay metrology of low contrast features (U.S. Patent No. 6724479). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/6724479

Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile

Loading…