Patent ID: 6624429
Filing Date: 2003-09-23
Classification: B82Y,H01J

Abstract:
A lithographic method for producing an exposure pattern on a curved substrate field of a substrate, the substrate field comprising material sensitive to exposure to an energetic radiation, the method comprisingproducing a wide, substantially parallel beam of said energetic radiation, illuminating a planar mask having a structure pattern of a set of transparent windows with said substantially parallel beam to form a structured beam, and imaging the structure pattern onto the substrate by means of the structured beam for producing a pattern image of a spatial distribution of irradiation over the substrate, wherein the center of curvature of the substrate field is positioned on a line as defined by a ray of the bream running through a pattern center defined on the mask within the area of the structure pattern, the windows of the structure pattern being arranged in a manner that along each radius from the pattern center, the radial spacing of said windows decreases with increasing radius from the pattern center, and wherein the direction of incidence of said beam onto the mask is varied through a sequence of inclinations with respect to the normal axis to the mask, the sequence of inclinations being adapted to merge those exposure pattern components which result from neighboring windows of the structure pattern, the exposure with respect to the sequence of inclinations superposing into a spatial distribution of exposure dose on the substrate, said distribution exceeding the specific minimum exposure dose of said resist material within only one or more regions of the substrate field, said region(s) forming the exposure pattern.