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. 13, 2006
Filed:
Sep. 20, 2001
Roger R. Lowe-webb, Sunnyvale, CA (US);
Roger R. Lowe-Webb, Sunnyvale, CA (US);
Nanometrics Incorporated, Milpitas, CA (US);
Abstract
An overlay target for spectroscopic measurement includes at least two diffraction gratings, one grating overlying the other. The diffraction gratings may include an asymmetry relative to each other in order to improve resolution of the presence as well as the direction of any mis-registration. For example, the asymmetry between the two diffraction gratings may be a phase offset, a difference in pitch, line width, etc. The overlay target may be spectroscopically measuring, for example, using an optical model and a best fit analysis. Moreover, the overlay target may be optimized by modeling the overlay target and adjusting the variable parameters and calculating the sensitivity of the overlay target to changes in variable parameters.