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. 04, 2010
Filed:
Dec. 14, 2007
Sanjeev Kaushal, San Jose, CA (US);
Sairam Sankaranarayanan, Fremont, CA (US);
Kenji Sugishima, Tokyo, JP;
Sanjeev Kaushal, San Jose, CA (US);
Sairam Sankaranarayanan, Fremont, CA (US);
Kenji Sugishima, Tokyo, JP;
Tokyo Electron Limited, Tokyo, JP;
Abstract
A method for correcting systematic errors in an optical measurement tool in which a first diffraction spectrum is measured from a standard substrate including a layer having a known refractive index and a known extinction coefficient by exposing the standard substrate to a spectrum of electromagnetic energy. A tool-perfect diffraction spectrum is calculated for the standard substrate. A hardware systematic error is calculated by comparing the measured diffraction spectrum to the calculated tool-perfect diffraction spectrum. A second diffraction spectrum from a workpiece is measured by exposing the workpiece to the spectrum of electromagnetic energy, and the measured second diffraction spectrum is corrected based on the calculated hardware systematic error to obtain a corrected diffraction spectrum.