METHOD AND APPARATUS FOR MEASURING DISTRIBUTION OF DIFFRACTION FACTOR

PROBLEM TO BE SOLVED: To highly accurately measure diffraction factor distribution of a specimen.SOLUTION: In a state that a specimen 140 is arranged in each of media 1,2 having diffraction factors respectively different from that of the specimen 140, reference light is made incident on the specimen 140, transmitted wavefront of the specimen 140 is measured in each of the media 1, 2 and in each of a plurality of different arrangements of the specimen 140 in each of the media 1, 2 (S204), a wavefront aberration corresponding to a difference between each transmitted wavefront and a reference transmitted wavefront is found out (S205), the influence of a shape error of the specimen 140 is removed by using two wavefront aberrations of the specimen 140 arranged on the same position to acquire a diffraction factor distribution projection value of the specimen 140 (S50), and three-dimensional diffraction factor distribution information of the specimen 140 is acquired from a plurality of diffraction factor distribution projection values corresponding to a plurality of arrangements (S70).