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:
Jun. 12, 2007
Filed:
Jun. 02, 2004
Abdurrahman Sezginer, Los Gatos, CA (US);
Robert Shinagawa, Cupertino, CA (US);
Hsu-ting Huang, San Jose, CA (US);
Abdurrahman Sezginer, Los Gatos, CA (US);
Robert Shinagawa, Cupertino, CA (US);
Hsu-Ting Huang, San Jose, CA (US);
Tokyo Electron Limited, Tokyo, JP;
Abstract
A method for measuring overlay in a sample includes obtaining an image of an overlay target that includes a series of grating stacks each having an upper and lower grating, each grating stack having a unique offset between its upper and lower grating. The image is obtained with a set of illumination and collection optics where the numerical aperture of the collection optics is larger than the numerical aperture of the illumination optics and with the numerical apertures of the illumination and collection optics are selected so that the unit cells of gratings are not resolved, the grating stacks are resolved and they appear to have a uniform color within the image of the overlay target.