Patent ID: 9053280
Filing Date: 2015-06-09
Classification: G03F,G06F

Abstract:
1. A method implemented by a computer of optimizing an initial design rule into an updated design rule for producing a mask layout to be imaged by a lithographic apparatus, the method comprising: selecting an initial design rule that specifies a minimum separation between features in the mask layout; selecting an autocorrelation function associated with a predefined optical condition of the lithographic apparatus; selecting respective mask transmittance functions for at least two features separated from each other by a distance in the mask layout; determining, using the computer, a change in illumination intensity at locations of a wafer plane associated with the at least two features as a function of perturbation of the distance between the at least two features, wherein a mathematical function for determining the change in illumination intensity per perturbation of the distance is derived using the mask transmittance functions and the autocorrelation function; and updating the initial design rule to generate the updated design rule specifying a new minimum separation between features by optimizing the change in illumination intensity to identify an optimal perturbation of the distance between the at least two features.