Patent ID: 8351037
Filing Date: 2013-01-08
Classification: G03F

Abstract:
1. A method of matching at least one lithographic tool using a programmable illuminator, said method comprising: providing reference lithographic data from a reference physical illumination tool or an ideal illumination tool; generating measured lithographic data from a lithographic tool having a programmable illuminator; calculating a difference between said reference lithographic data and said measured lithographic data; minimizing, employing a machine that runs a linear programming solver, a metric of difference d with respect to {right arrow over (s)} by solving a linear programming problem (LP) under a set of constraints, said set of constraints including constraints a wherein {right arrow over (s)} is a list of unknown source pixel intensities, s j is a j-th component of {right arrow over (s)}, j is an index running from 1 to J Max , J Max is a total number of source pixels, S Max,j is a j-th component of a maximum source pixel intensity, {right arrow over (s)} 0 ·{right arrow over (I)} r,0 denotes an intensity provided by a reference source that generates said reference lithographic data at an r-th sample point, {right arrow over (s)}·{right arrow over (I)} r denotes a corresponding intensity provided by a source of said lithographic tool at said r-th sample point, r is an index running from 1 to r Max , r Max is a total number of sample points, {right arrow over (s)} 0 ·{right arrow over (İ)} r is an image slope dI/dx in the direction perpendicular to the edge contour under conditions where said tool prints a reference pattern, X is a measured edge position at an r-th sample point when a reference source is used in said lithographic tool, and X 0 is a corresponding position in a corresponding measurement taken on exposures with said reference physical illumination tool or an equivalent calculated from said ideal illumination tool.