Patent ID: 7801709

Claim:
A simulation method using a computer that provides, through simulation, information on a transfer pattern to be produced on a wafer upon transferring a predetermined mask pattern thereto by optical photolithography, comprising the steps of the computer: accepting an input of a measured dimension of said transfer pattern; calculating a light intensity at each of a plurality of positions on said transfer pattern; calculating a light intensity gradient at each of said positions based on said light intensity; multiplying said light intensity, a tentative optical reaction coefficient and said light intensity gradient to thus obtain a modified value, and adding said modified value to said light intensity thereby giving a modified light intensity; and deciding a threshold value and an optical reaction coefficient by regression calculation such that a difference between said measured dimension and a calculated dimension becomes minimal under said modified light intensity, employing as a constant said threshold value of said light intensity at a pair of edges that define said calculated dimension of said transfer pattern in said simulation.