Thermal damage characterization of silicon wafer subjected to CW laser beam

The objective of this study is to evaluate the thermal damage characterization of a silicon wafer subjected to a CW laser beam. The variation in temperature and stress during laser beam irradiation has been predicted using a three-dimensional numerical model. The simulation results indicate that the specimen might crack when a 93-W/cm² laser beam is irradiated on the silicon wafer, and surface melting can occur when a 186-W/cm² laser beam is irradiated on the silicon wafer. In experiments, straight cracks in the [110] direction were observed for a laser irradiance exceeding 102 W/cm ². Furthermore, surface melting was observed for a laser irradiance exceeding 140 W/cm². The irradiance for surface melting is less than that in the simulation results because multiple reflections and absorption of the laser beam might occur on the surface cracks, increasing the absorbance of the laser beam.