Patent ID: 6792591
Filing Date: 2004-09-14
Classification: G03F

Abstract:
A method of identifying an extreme interaction pitch region when designing a mask pattern for transferring a lithographic pattern 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 a pitch region containing said first pitch as an extreme interaction pitch region if the value of the derivative of the log-slope of said total illumination intensity with respect to pitch is approximately equal to zero.