Patent ID: 7563661

Claim:
A method for crystallizing a semiconductor film, comprising the steps of: oscillating a first laser beam by a first oscillator; oscillating a second laser beam by a second oscillator; processing the first laser beam and the second laser beam, so as each have a linear cross section extending along a surface of the semiconductor film; irradiating the semiconductor film with the first laser beam and the second laser beam concurrently; moving an irradiated portion of the semiconductor film along a direction substantially perpendicular to the linear cross section of the first laser beam and the second laser beam, wherein the first laser beam is incident on the semiconductor film at a first angle with respect to a plane extending perpendicularly from the surface of the semiconductor film and extending along the linear cross section of the first laser beam and the second laser beam, and wherein the second laser beam is incident on the semiconductor film at a second angle opposite the first angle of the first laser beam with respect to the plane.