Abstract

Controllability of laser induced damages (LID) in sapphire using focused ultrashort pulsed laser beam has been studied to develop kerf-loss less slicing process in wafer manufacturing by scanning focus spot into sapphire ingot. Micro Raman tomographic imaging technique (µRTI) is used for nondestructive measurement of LID, and residual stress accompanied with damaging marks. Stress field distribution can be observed surrounding LID at 15 micron-depth from the surface, in the tomographic images with the peak features of 2D Raman spectral dataset. The severity of LID mark could be controlled by the energy and the shot number of laser pulses at a spot area.

© 2022 IEEE