Patent ID: 6686100
Filing Date: 2004-02-03
Classification: G03F

Abstract:
A method of carrying out optical proximity correction in the design of a reticle for exposing a photoresist on a substrate in photolithography using a lens having a focal plane, the method including the steps of:generating a dense-isolated offset focus/exposure matrix, containing dense-isolated offset values, being the difference between values for the linewidth of dense and isolated lines printed on said substrate, as a function of focal plane position, for each of a plurality of different exposures; selecting from among the contours of the dense-isolated offset focus/exposure matrix for each different exposure, the flattest contour, being the contour which is flattest in terms of variation of the dense-isolated offset over the range of focal plane positions of interest; and carrying out optical proximity correction on the basis that the exposure will be a selected exposure corresponding to said flattest contour.