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:
Aug. 30, 2011
Filed:
Apr. 14, 2009
Amyn A. Poonawala, Portland, OR (US);
Benjamin D. Painter, Portland, OR (US);
Levi D. Barnes, Hillsboro, OR (US);
Amyn A. Poonawala, Portland, OR (US);
Benjamin D. Painter, Portland, OR (US);
Levi D. Barnes, Hillsboro, OR (US);
Synopsys, Inc., Moountain View, CA (US);
Abstract
Some embodiments provide techniques and systems to identify locations in a target mask layout for placing assist features. During operation, an embodiment can determine a spatial sampling frequency to sample the target mask layout, wherein sampling the target mask layout at the spatial sampling frequency prevents spatial aliasing in a gradient of a cost function which is used for computing an inverse mask field. Next, the system can generate a grayscale image by sampling the target mask layout at the spatial sampling frequency. The system can then compute the inverse mask field by iteratively modifying the grayscale image. The system can use the gradient of the cost function to guide the iterative modification process. Next, the system can filter the inverse mask field using a morphological operator, and use the filtered inverse mask field to identify assist feature locations in the target mask layout.