Back to results
US 7,480,891 B2Granted
Method and apparatus of model-based photomask synthesis
AssigneeCadence Design Systems, Inc.
InventorAbdurrahman Sezginer
Life of this patent
Estimating the term…
Abstract
An apparatus and method for improving image quality in a photolithographic process includes calculating a figure-of-demerit for a photolithographic mask function and then adjusting said photolithographic mask function to reduce the figure of demerit.
Claims55
A method of improving image quality in a photolithographic process, comprising:
- calculating a derivative of a figure-of-demerit for a photolithographic mask function with respect to an aspect of the photolithographic mask function;
- and
- adjusting said photolithographic mask function to reduce said figure-of demerit using said calculation.
A method of generating assist features comprising:
- selecting a mask function defined by a set of layout polygons, wherein each individual layout polygon has a set of edges;
- assigning a figure-of-demerit to said mask function;
- moving individual edges of said set of polygons to reduce the figure-of-demerit;
- after said step of moving, designating a neighborhood for each individual edge of each individual layout polygon as an assist-feature exclusion zone;
- and
- placing an assist feature outside all designated neighborhoods according to a derivative of the figure-of-demerit with respect to the mask function.
3 more elements
A method of adjusting subresolution assist features included in a set of layout polygons indicative of a mask function, the method comprising:
- assigning a figure-of-demerit to said mask function;
- calculating a derivative of the figure-of-demerit with respect to the mask function;
- and
- adjusting a subresolution assist feature according to said derivative.
1 more element
Dependencies are inferred from the claim text.