Patent ID: 8115137

Claim:
A laser annealing method for shaping pulse-type laser beam, which is emitted from a solid state laser source, condensing the shaped laser beam as a rectangular beam on a surface of a semiconductor film, scanning the semiconductor film with the rectangular beam relatively in a minor axial direction, and thereby crystallizing the semiconductor film with laser irradiation, the laser annealing method comprising: projecting the laser beam onto the surface of the semiconductor film in the minor axial direction of the rectangular beam, using a minor-axis condenser lens to condense incident light in the minor axial direction and a projection lens to project light, which comes from the minor-axis condenser lens, onto the surface of the semiconductor film, and detecting positional variation in a vertical direction of the semiconductor film in a laser irradiated portion of the semiconductor film, and moving the minor-axis condenser lens in an optical axis direction based on a value of the detection.