Laser beam induced thermal-crack propagation for asymmetric linear cutting of silicon wafer

The laser induced thermal-crack propagation (LITP) has been reported to have excellent kerf quality in the cutting of silicon wafer. However, the trajectory deviation problem under asymmetric cutting have obstructed the application of this technology in silicon wafer cutting. In this study, a pre-crack guiding laser cleaving (PCGLC) method has been presented to solve the problem of path deviation in asymmetric linear cutting of silicon wafer. The effects of the pre-crack parameters including groove width and groove depth as well as the processing parameters including laser power and laser scanning speed on the processing quality are investigated in experiments. The interaction effects of laser power and laser scanning speed on kerf quality are discussed. A parameter selection guidance based on minimum required laser power is proposed and the optimum kerf quality is obtained. Thermal crack propagation simulation reveals the none-deviation mechanism in PCGLC. From experimental and simulation studies, the PCGLC can obtain a good processing quality with good kerf quality and unbiased trajectory.