Patent ID: 6245470
Filing Date: 2001-06-12
Classification: G02B,G03F

Abstract:
A spherical aberration quantity estimating method, comprising the steps of:exposing an aberration estimating mask pattern using photoresist and an optical projection system, the aberration estimating mask pattern including:a transparent substrate;a plurality of micro patterns selectively formed on the transparent substrate, each micro pattern having a dimension which is on the order of an exposure wavelength; anda plurality of larger patterns which are selectively formed on the transparent substrate, each larger pattern having a size which is more than three times the exposure wavelength;wherein each of the micro patterns and a corresponding one of the larger patterns are combined with each other, wherein a plurality of combinations of the micro patterns and the larger pattern are placed on the transparent substrate;observing a plurality of finished micro patterns and larger patterns through a Scanning Electron Microscope;finding a best focus position of each of the micro patterns;finding a best focus position of each of the larger patterns;measuring a quantity of a shift of the best focus position among the micro patterns and among the larger patterns; andestimating a quantity of the spherical aberration from the quantity of the shift of the best focus position for both the micro and larger patterns as a function of positioning in the estimating mask pattern.