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:
Dec. 04, 2012
Filed:
Apr. 25, 2011
Robert L. Hsieh, Los Altos, CA (US);
Warren W. Flack, San Jose, CA (US);
Robert L. Hsieh, Los Altos, CA (US);
Warren W. Flack, San Jose, CA (US);
Ultratech, Inc., San Jose, CA (US);
Abstract
A phase-shift mask having a checkerboard array and a surrounding sub-resolution assist phase pattern. The checkerboard array comprises alternating phase-shift regions R that have a relative phase difference of 180 degrees. The sub-resolution assist phase regions R' reside adjacent corresponding phase-shift regions R and have a relative phase difference of 180 degrees thereto. The sub-resolution assist phase regions R′ are configured to mitigate undesirable edge effects when photolithographically forming photoresist features. Method of forming LEDs using the phase-shift mask are also disclosed.