Patent ID: 8502962

Claim:
A non-transitory computer readable storage medium storing a program executable by a computer to execute a method of calculating a light intensity distribution to be formed on a pupil plane of an illumination optical system in an exposure apparatus which illuminates an original with light emitted from said illumination optical system, and exposes a substrate by projecting a pattern of the illuminated original onto the substrate via a projection optical system, the method comprising the steps of: determining an impulse response function of said projection optical system through a process of performing Fourier transform on a pupil function of said projection optical system; setting a length to a second zero point of the impulse response function from the origin as a response length, extracting, from elements forming a target pattern to be formed on the substrate, only elements for each of which the spacing to an adjacent element is equal to or smaller than the response length, and determining a function indicating the extracted pattern as an image function; and obtaining the light intensity distribution to be formed on the pupil plane of said illumination optical system based on the pupil function, the determined impulse response function, and the determined image function.