Patent ID: 6519760
Filing Date: 2003-02-11
Classification: G03F

Abstract:
A method of identifying an extreme interaction pitch region when designing a mask for transferring a lithographic pattern corresponding to an integrated device from said mask onto a substrate by use of a lithographic apparatus, said method comprising the steps of:(a) determining an illumination intensity for a first pitch and a first illumination angle, (b) determining an illumination intensity for said first pitch and a second illumination angle, said second illumination angle being rotationally symmetric with respect to said first illumination angle, (c) determining a total illumination intensity for said first pitch by combining the illumination intensity associated with said first illumination angle and said second illumination angle, (d) determining the log-slope of said total illumination intensity, and (e) identifying said first pitch as an extreme interaction pitch region if the value of the derivative of the log-slope of said total illumination intensity divided by the derivative of said first pitch is approximately equal to zero.