Patent ID: 6770409
Filing Date: 2004-08-03
Classification: G03F

Abstract:
In a microlithography process, a method for simulating the cross-sectional profile of developed resist corresponding to an exposed pattern element, the method comprising the steps:(a) with respect to a layer of the resist, inputting data concerning a distribution of molecular weight and of mean density of the resist; (b) from the input data, calculating a volume distribution of molecules of the resist; (c) at a resist cross-section, dividing a line, indicating contact of a surface of the resist with a resist-developer solution, into increments; (d) based on a distribution of development rate for the resist, assigning respective weighting parameters to each increment; (e) after a selected amount of resist-development time, determining, using respective random numbers weighted by the weighting parameters used in step (d), whether separation has occurred in each increment; (f) assuming that each molecule of the resist is separated from the layer of resist in each increment in which separation is going to occur, determining for each such increment a respective volume of separated resist molecules, using respective random numbers weighted based on the volume distribution calculated in step (b); (g) using random numbers, determining respective widths of the volumes of separated resist molecules and calculating respective depths of the volumes determined in step (f); and (h) according to an array of the respective depths of the volumes, extending a line connecting the depths, the line indicating a simulated profile of the resist surface after separation.