Patent ID: 8080450

Claim:
A method of manufacturing a semiconductor thin film, comprising: depositing a diffusion-preventing film on a translucent substrate; depositing an insulating film having a refractive index n on the diffusion-preventing film; depositing an amorphous thin film on the insulating film; and forming a polycrystalline semiconductor thin film from the amorphous thin film by irradiating the amorphous thin film from a bottom of the insulating film with a laser beam which has a beam shape of a band shape extending along a length direction and has a wavelength λ, a plurality of times from a lower side of the amorphous thin film facing the insulating film in a direction so that the laser beam passes through the substrate, the diffusion-preventing film, and the insulating film to the amorphous thin film, while an irradiation position of the laser beam is shifted each of the plurality of times in a width direction of the band shape by a distance smaller than a width dimension of the band shape, wherein forming the polycrystalline semiconductor thin film being conducted to form crystal grain boundaries which extend in the width direction and are disposed at a mean spacing measured along the length direction and ranging from (λ/n)×0.95 to (λ/n)×1.05 inclusive, and crystal grain boundaries which, in a region between crystal grain boundaries adjacent to each other and extending in the width direction, extend in the length direction and are disposed at a mean spacing measured along the width direction and ranging from (λ/n)×0.95 to (λ/n)×1.05 inclusive.