Patent ID: 7927983

Claim:
A method of manufacturing a semiconductor device comprising: forming a semiconductor film over a substrate; shielding attenuation regions which are ends in a longitudinal direction of a laser light emitted from a laser by using a slit provided within 1 cm from the surface to be irradiated so that the attenuation regions do not reach the surface to be irradiated, thereby forming a linear laser light; and irradiating the semiconductor film with the linear laser light while relatively shifting the surface to be irradiated in a shift direction which is perpendicular to the longitudinal direction, wherein a distance between the ends of the laser light in the longitudinal direction is increased as the laser light approaches the slit before shielding the attenuation regions by the slit, and wherein the distance between the ends of the laser light in the longitudinal direction is made constant as the laser light approaches the surface to be irradiated after shielding the attenuation regions by the slit.