Method and equipment for simulation
View Patent ↗The simulation equipment has division unit for dividing a layout of a photo mask (mask layout) into a plurality of areas, average light intensity value calculation unit for calculating an average value of light intensity in each of the areas, smoothing unit for subjecting the calculated average value to smoothing processing, and multiplication unit for multiplying the smoothed average value by a predetermined multiplier.
1. A computer-readable storage medium having stored thereon a computer program for use in optical corrections to obtain a more accurate optical image for simulating an amount of occurrence of local flare which occurs in an exposure process in manufacturing a semiconductor executable to perform the steps of:
dividing a layout of a photo mask into a plurality of areas;
calculating an average value of light intensity in each of the areas;
simulating and estimating an amount of occurrence of local flare in each of the areas on the basis of each of the average values, for use in optical corrections to obtain a more accurate optical image, and
correcting dimensions of the photo mask based on the estimated amount of occurrence of local flare, wherein
when a circular-shaped light source is used, the average value of light intensity
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and N is 1 or more natural number, F k is a weighting factor of diffracted light, S k is the amplitude of the diffracted light, and F k =A k /(σ 2 π) where A k is the area shared between a circle C having a radius NA, the numerical aperture of a lens, and a circle S k having a radius of the light source with respect to NA, and σ is the radius of the circular shaped light source with respect to NA, and
when a ring-shaped light source is used, the average value of light
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intensity and N is 1 or more natural number, F k ′ is a weighting factor of diffracted light, S k ′ is the amplitude of the diffracted light, and F k ′=A k ′/(σ 2 2 π−σ 1 2 π) where A k ′ is the area shared between a circle C having a radius NA, the numerical aperture of a lens, and a ring S k ′ having a radius of the light source with respect to NA, where σ 1 is the inside radius and σ 2 is the outside radius of the ring-shaped light source with respect to NA.
2. The simulation method according to claim 1 , wherein
each of the average values is subjected to smoothing processing, a smoothed average value is multiplied by a first multiplier, and an obtained value is evaluated as the amount of occurrence of local flare in each of the areas.
3. The simulation method according to claim 1 , wherein
when the average value of light intensity in each of the areas is calculated, diffracted light is calculated by a Fourier transformed image of each of the areas of the layout, and the average value is calculated by multiplying the light intensity of the diffracted light passing through a projection lens by a second multiplier.
4. The simulation method according to claim 1 , wherein
each of the values evaluated as the amount of occurrence of local flare is added to the light intensity in order to simulate an optical image.
5. The simulation method according to claim 1 , wherein
each of the values evaluated as the amount of occurrence of local flare is used in optical proximity correction.