Influence of the condition parameters on UV pulsed laser polishing of sapphire wafer

In this paper, the study on polishing characteristics of sapphire using a short pulse (25 ps) ultraviolet laser (355 nm) was conducted. The polished surfaces were observed and their surface roughness R_a was measured to analyze the correlations of surface roughness with pulse conditions, such as the influences of laser fluence, incidence angle, scanning speed and scanning manner. The research results show that the surface roughness R_a of polished sapphire wafer was improved obviously as the fluence increases, with the increase of laser incidence angle or scanning times, the surface roughness of sapphire decreases. And the surface roughness increases with the increase of laser scanning speed.