Patent ID: 8092960

Claim:
A method for making an exposure mask used with an exposure apparatus, said method comprising the steps of: calculating an exposure amount distribution for a photosensitive material using design data of a three-dimensional shape, said exposure amount distribution being calculated by (i) adding a flare amount of an optical system of an exposure apparatus to an effective exposure amount and (ii) calculating a transmittance distribution of said exposure mask based on said exposure amount distribution; calculating a first pitch in a first direction and a second pitch in a second direction using optical conditions of said exposure apparatus; arranging a plurality of pattern blocks to form said exposure mask with each pattern block having a blocking pattern and a light transmissive pattern, whereby an area ratio of said light blocking pattern to said transmissive pattern can vary, the pattern blocks having a first constant size in the first direction and a second constant size in the second direction; and arranging a projection magnification lens in-between a photosensitive material and said exposure mask, wherein, said first and second pitches are values whose minimums are represented by the relationship: Pmin≦λ/(NA×(1+σ)), Pmin is a minimum pitch, λ is an exposure wavelength, NA is a numerical aperture of the exposure apparatus, σ is a coherence factor, said first and second pitches are the same value or different values, said plurality of pattern blocks are contiguously arranged (a) in a first direction at said first pitch in said first direction and (b) in a second direction at said second pitch in said second direction, and said area ratio of said light blocking pattern to said transmissive pattern varies with location as a function of a continuous variable.