Patent ID: 7207030
Filing Date: 2007-04-17
Classification: G03F

Abstract:
1. A method for improving a photolithographic simulation of the projection of a pattern of structure elements formed on a photomask onto a substrate comprising: providing a pattern of structure elements; providing a simplifying simulation model that describes the physical or chemical processes during lithography with an exposure apparatus without taking account of frequency-dependent transmissions of different orders of diffraction; executing a simulation of the projection of the pattern onto a resist layer applied on a substrate of a semiconductor wafer in the exposure apparatus for the purpose of forming a patterned resist layer with the simulation model; calculating an intensity distribution in the substrate plane in a two-dimensional simulation of the imaging of the pattern with calculation of an intensity distribution in the Fourier space; providing a two-dimensional filter function; calculating a frequency-dependent intensity loss that occurs during the execution of a simulation of the pattern by multiplication of the intensity distribution in the Fourier space by the filter function in order to achieve a matching of the simulation result of the simulation model with a more exact simulation that takes account of the frequency-dependent transmission of different orders of diffraction; and optimizing the geometry of the structure elements of the pattern and/or parameters of the lithographic projection in order to achieve an improved dimensional accuracy for subsequent imagings.