LASER BEAM IRRADIATION APPARATUS AND LASER BEAM IRRADIATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a laser beam irradiation apparatus for irradiating a laser beam for working and a laser beam irradiation method for performing high quality working.

SOLUTION: A laser beam irradiation apparatus comprises: a laser beam source for emitting a first beam along a first path and a second beam along a second path; a stage for holding a work having a surface to be worked; a beam overlapper for overlapping the first beam and the second beam so that the first beam propagating along the first path and the second beam propagating along the second path propagate along a common third path; a first optical system which is arranged on the first path and makes an optical strength distribution uniform in a cross section of the first beam on a first virtual face on the third path; a second optical system which is arranged on the second path and not only shapes the cross section of the second beam such that the cross section of the second beam becomes bigger than the cross section of the first beam on the first virtual face and includes the cross section of the first beam within the cross section of the second beam, but also makes an optical strength distribution uniform in the cross section on the first imaginary face; and a first image formation optical system for forming images of cross sections of the first beam and second beam on the first virtual face on the surface to be worked. A power density of the second beam on the first virtual face is lower than a power density of the first beam.

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