OPTICAL MEMBER FOR OPTICAL LITHOGRAPHY AND EVALUATION METHOD THEREFOR

摘要

Amethod of evaluating a refractive index homogeneity of an optical member for photolithography, the method comprising:
a measurement step of transmitting light having a predetermined wavelength λ through the optical member so as to measure a wavefront aberration;a Zernike fitting step of expanding thus measured wavefront aberration into a polynomial of a Zernike cylindrical function system;a first separating step of separating individual components of the polynomial into a rotationally symmetric element, an odd-symmetric element, and an even-symmetric element; anda second separating step of separating individual components of the polynomial into a plurality of parts according to a degree thereof.