Patent ID: 6573162
Filing Date: 2003-06-03
Classification: B23K,G02B,H01L,H01S

Abstract:
A method of manufacturing a semiconductor device comprising:emitting a first laser beam from a laser oscillator having a cross section perpendicular to a propagation direction of the first laser beam; expanding the cross section of the first laser beam only in a longitudinal direction of the cross section; dividing the first laser beam into at least second and third divided laser beams in a width direction of the cross section by using at least first and second mirrors; converging said at least second and third divided laser beams to a same irradiation area of a semiconductor film wherein an energy distribution of the converged laser beam is better than that of the first beam; moving a relative position of the irradiation area of the semiconductor film in a direction perpendicular to said longitudinal direction, thereby crystallizing the semiconductor film, wherein a difference of optical path lengths between said at least second and third divided laser beams is larger than a coherent length of said first laser beam.