Laser irradiation apparatus, laser irradiation method, beam homogenizer, semiconductor device, and method of manufacturing the semiconductor device

摘要

A beam homogenizer configured for converting an originally rectangular beam into a linear shape having a two stage energy distribution in a width direction comprising a first beam width (w1) having a first energy density (E1) and a second beam width (w2) having a second energy density (E2), the beam homogenizer comprising: an optical lens (501) for dividing an incident laser beam in width direction into parts and enlarging the parts; and an optical system (204, 208) for synthesizing said parts of said laser beam divided by said optical lens in a width direction, whereby the synthesized laser beam has a two stage energy distribution in the width direction, wherein said optical lens (501) includes a plano-convex lens (602, 603, 604, 605) as a cylindrical lens and a plano-convex lens cut into halves (601, 606) perpendicular to its plane surface as a semi-cylindrical lens.