Comparative investigation of subsurface damages induced on sapphire with different machining methods using micro Raman spectroscopy

The objective of this research is to propose and develop an evaluation procedure by use of Raman spectral features to distinguish the mechanical, thermal and chemical effects on the surface integrity of sapphire wafer generated by different machining process. In this paper, several types of process; grinding (brittle-mode and ductile-mode), chemo mechanical abrasive machining, ion milling and laser ablation, have been put into investigation. The obtained results have been discussed to understand the measurement properties of material damages by various machining method, and to understand the dominant factors of damage induction.