PHASE MODULATION DEVICE, PHASE MODULATION DEVICE FABRICATION METHOD, CRYSTALLIZATION APPARATUS, AND CRYSTALLIZATION METHOD
A phase shifter which modulates the phase of incident light has a light-transmitting substrate such as a glass substrate, and a phase modulator such as a concavity and convexity pattern which is formed on the laser beam incident surface of the light-transmitting substrate and modules the phase of incident light. A light-shielding portion which shields light in the peripheral portion where the optical intensity distribution decreases of the phase modulator is formed on the laser beam incident surface or exit surface of the phase shifter, thereby shielding the peripheral light in the irradiation surface of the incident laser beam.
1 . A crystallization apparatus in which a laser beam from a laser source irradiates a substrate to be processed on a suscepter via a homogenizing optical system, a phase modulation device, and an image formation optical lens system, thereby crystallizing an irradiated surface, comprising:
light-shielding means which is provided on the phase modulation device between an exit surface of the homogenizing optical system and an incident surface of the image formation optical lens system, and shields peripheral light of exit light from the homogenizing optical system.
2 . An apparatus according to claim 1 , wherein the light-shielding means is an annular light-shielding member.