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:
Apr. 21, 2009
Filed:
Jul. 11, 2006
Youxian Wen, Fremont, CA (US);
Shifang LI, Pleasanton, CA (US);
Youxian Wen, Fremont, CA (US);
Shifang Li, Pleasanton, CA (US);
Tokyo Electron Limited, Tokyo, JP;
Abstract
In determining position accuracy of double exposure lithography using optical metrology, a mask is exposed to form a first set of repeating patterns on a wafer, where the repeating patterns of the first set have a first pitch. The mask is then exposed again to form a second set of repeating patterns on the wafer. The repeating patterns of the second set of repeating patterns interleave with the repeating patterns of the first set of repeating patterns. The wafer is then developed to form a first set of repeating structures from the first set of repeating patterns and a second set of repeating structures from the second set of repeating patterns. A first diffraction signal is measured of a first repeating structure from the first set of repeating structures and a second repeating structure from the second set of repeating structures, where the first repeating structure is adjacent to the second repeating structure. A second pitch between the first repeating structure and the second repeating structure is determined using the first measured diffraction signal. Position accuracy of the mask used to form the second set of repeating patterns is determined based on the determined second pitch and the first pitch.