Patent Document ID: 8056024
Application ID: 12344208
Patent Status: 1

Claim One:
1. A method for modifying a photomask layout to obtain a correctly exposed photomask image layout on a wafer comprising: providing a photomask layout having at least an edge with at least a first evaluation point and a second evaluation point on the edge by using a computer; interpreting the photomask layout to generate an interpreted photomask layout, wherein the interpreted photomask layout comprises an interpreted edge pattern, and the interpreted edge pattern has a third evaluation point corresponding to the first evaluation point and a fourth evaluation point corresponding to the second evaluation point; measuring a distance between the first evaluation point and the third evaluation point to obtain a first shift; measuring a distance between the second evaluation point and the fourth evaluation point to obtain a second shift; calculating a shift gradient between the first shift and the second shift, wherein the shift gradient is calculated by using the following equation: 
 ΔS=(S 1 −S 2 )÷h wherein ΔS is the shift gradient, S 2 is the second shift, S 1 is the first shift, and h is the distance between the first evaluation point and the second evaluation point; and estimating a number of segment(s) between the first evaluation point and the second evaluation point.