Patent ID: 9174305
Filing Date: 2015-11-03
Classification: B23K,G01N,H01L

Abstract:
1. A laser processing apparatus for removing a sapphire substrate from an optical device wafer configured by forming an optical device layer on a front side of said sapphire substrate through a buffer layer, said laser processing apparatus comprising: a chuck table for holding said optical device wafer; laser beam applying means for applying a pulsed laser beam to said optical device wafer held on said chuck table to break said buffer layer, wherein said pulsed laser beam is sequentially set to each of plurality of different powers; plasma detecting means for detecting the light intensity of plasma light produced in said buffer layer by the application of said pulsed laser beam from said laser beam applying means to said optical device wafer, said plasma detecting means detecting the light intensity of a predetermined wavelength region of said plasma light generated from a substance forming said buffer layer; a control means for receiving a voltage signal corresponding to the light intensity detected by the plasma detection means and for outputting the voltage signal corresponding to each of said different powers of said pulsed laser beam; displaying means for displaying said voltage signals corresponding to the light intensity of said plasma light detected by said plasma detecting means such that each of said voltage signals displayed is associated with one of said powers of said pulsed laser beam.