Patent ID: 6487503
Filing Date: 2002-11-26
Classification: G03F

Abstract:
A method for estimating a shape of a chemically amplified resist by a computer simulation, comprising the steps of:calculating diffusion of a catalyst species in the chemically amplified resist upon post-baking process by approximation with a Gaussian distribution G(xâ€², yâ€²), represented as: G(xâ€², yâ€²)=(1(2&pgr;dl2))exp(âˆ’(xâ€²2+yâ€²2)/(2dl2)), wherein dl is a diffusion length; calculating a light intensity distribution on the chemically amplified resist upon exposure to light wherein said light intensity distribution, I(x,y) is calculated in accordance with: I(x,y)=âˆ«âˆ«(p, q)[âˆ«âˆ«F(xo, yo)K(xâˆ’xo, yâˆ’yo)exp((i2&pgr;)/&lgr;(pxo+qyo))dxo dyo ]2dpdq â€ƒwhere x and y are two-dimensional coordinate values representative of a point on a wafer, S, which is a function representative of an effective light source, is a function representative of an intensity of light at a point (p,q) on the light source, F is a function representative of a mask transmittance at a point (xo, yo) on the mask, K is a pupil function, &lgr; an exposure light wavelength, i an imaginary unit such that i2=âˆ’1, and &pgr; is a circular constant, said pupil function K being represented as: K(x,y)=Ko(x,y)exp((2&pgr;ifNA2(x2+y2))/(&lgr;a2)) where f is a focus value, NA a numerical aperture, a an aperture diameter, with Ko(x,y) being 2 if (x2+y2)/a2 is less than or equal to 1 and 0 otherwise; correcting the light intensity distribution with the Gaussian distribution producing a corrected light intensity J(x,y) formed by a convolution integration of light intensity distribution I(x,y) represented by: J(x,y)=âˆ«âˆ«I(xâˆ’xâ€², yâˆ’yâ€²)G(xâ€², yâ€²)dxâ€²dyâ€²; â€ƒand performing calculation of the shape of a two-dimensional pattern of the chemically amplified resist based on the corrected light intensity distribution J(x,y) at arbitrary threshold value Ith.