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:
Feb. 24, 2009
Filed:
Jan. 27, 2005
Lawrence S. Melvin, Iii, Hillsboro, OR (US);
James P. Shiely, Aloha, OR (US);
Lawrence S. Melvin, III, Hillsboro, OR (US);
James P. Shiely, Aloha, OR (US);
Synopsys, Inc., Mountain View, CA (US);
Abstract
One embodiment of the present invention provides a system that improves the depth of focus during an optical lithography process. During operation, the system receives a mask layout. The system then selects an edge in the mask layout. Next, the system adds a notch to the edge to improve the depth of focus by helping to maintain a critical dimension associated with the edge as the optical lithography process drifts out of focus. Note that adding a notch to the edge adds a high spatial-frequency component to the mask layout. This high spatial-frequency component degrades as the optical lithography process drifts out of focus. This degradation causes the mask layout to allow more light into the pattern, which helps maintain the critical dimension, thereby improving depth of focus.