Patent ID: 8399184

Claim:
A method for laser interference lithography using a diffraction grating, comprising: (a) forming a photoresist layer on a work substrate to which a repeated fine pattern is to be formed; (b) forming a refractive index matching material layer on the photoresist layer; (c) forming on the refractive index matching material layer a diffraction grating layer having a period of diffraction grating within the range from λ/ng to λ/n0 (λ is a wavelength of laser beam, ng is a refractive index of the diffraction grating, and n0 is a refractive index in the air or in vacuum); and (d) exposing the photoresist layer by means of mutual interference of positive and negative diffracted lights with the same absolute value by inputting a laser beam perpendicularly to the diffraction grating layer.