Calculation system for inverse masks
First Claim
1. A computer system including one or more processors that are configured to execute a sequence of program instructions for computing mask data for the creation of one or more photolithographic masks that print a desired layout pattern on a wafer with a photolithographic printing system that is designed to print features at a predefined tightest pitch pattern, wherein the instructions cause the computer to:
- read all or a portion of a desired layout pattern;
define a set of mask data having a number of pixels that are assigned a transmission value;
determine an objective function that compares a simulation of the image intensity on a wafer to an ideal image intensity;
define a set of ideal image intensities from the desired layout pattern, wherein the maximum ideal image intensity is selected to be substantially equal to the maximum image intensity determined from a test image of features at the tightest pitch pattern produced by the photolithographic imaging system; and
minimize the objective function to determine the transmission values of the pixels in the mask data that will produce the desired layout on a wafer.
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Abstract
A system for calculating mask data to create a desired layout pattern on a wafer reads all or a portion of a desired layout pattern. Mask data having pixels with transmission values is defined along with corresponding optimal mask data pixel transmission values. An objective function is defined that compares image intensities as would be generated on a wafer with an optimal image intensity at a point corresponding to a pixel. The objective function is minimized to determine the transmission values of the mask pixels that will reproduce the desired layout pattern on a wafer.
21 Citations
18 Claims
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1. A computer system including one or more processors that are configured to execute a sequence of program instructions for computing mask data for the creation of one or more photolithographic masks that print a desired layout pattern on a wafer with a photolithographic printing system that is designed to print features at a predefined tightest pitch pattern, wherein the instructions cause the computer to:
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read all or a portion of a desired layout pattern; define a set of mask data having a number of pixels that are assigned a transmission value; determine an objective function that compares a simulation of the image intensity on a wafer to an ideal image intensity; define a set of ideal image intensities from the desired layout pattern, wherein the maximum ideal image intensity is selected to be substantially equal to the maximum image intensity determined from a test image of features at the tightest pitch pattern produced by the photolithographic imaging system; and minimize the objective function to determine the transmission values of the pixels in the mask data that will produce the desired layout on a wafer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification