Patent ID: 7695876
Filing Date: 2010-04-13
Classification: G03F

Abstract:
1. A method for identifying process window signature patterns, comprising: performing simulations of a lithography process, using a representation of a device area of a mask, at two or more non-nominal locations and at nominal condition in a process window to produce simulation results; determining simulated values from the simulation results for at least one metric at the two or more non-nominal locations and at nominal condition in the process window, wherein the simulated values for the at least one metric are determined at a plurality of locations within the device area; for each of the plurality of locations within the device area, determining a difference between simulated values for the at least one metric at the two or more non-nominal locations in the process window and the simulated value for the at least one metric at nominal condition; identifying a number of locations within the device area where the difference for the at least one metric is above a threshold; if the number of identified locations is greater than a predetermined number, modifying the threshold and identifying the locations within the device area where the difference for the at least one metric is above the threshold until the number of identified locations within the device area is less than the predetermined number; and assigning patterns associated with the number of identified locations within the device area that is less than the predetermined number to be signature patterns.