Patent ID: 7638729
Filing Date: 2009-12-29
Classification: B23K,C03B,G02F,Y02P,Y10T

Abstract:
1. An apparatus for cutting a substrate, comprising: a laser oscillator generating a femtosecond laser beam; a first beam splitter splitting the femtosecond laser beam into first and second femtosecond laser beams; a first condenser lens receiving the first femtosecond laser beam and condensing the first femtosecond laser beam to have a first focal depth; a second condenser lens receiving the second femtosecond laser beam, and condensing the second femtosecond laser beam to have a second focal depth different from the first focal depth; an optical attenuator between the first reflector and the first condenser lens to adjust energy of the femtosecond laser beam; and a second beam splitter receiving and splitting the first femtosecond laser beam condensed through the first condenser lens and the second femtosecond laser beam condensed through the second condenser lens, and irradiating the split first and second femtosecond laser beams at different depths in the direction vertical to the substrate to be cut, wherein the optical attenuator includes a λ/2 plate, a linear polarizer, and a λ/4.