Toward low-loss and low-roughness laser readily separable slicing of SiC wafers: The role of temporal pulse bursts

High-quality and efficient slicing of SiC wafers remains a critical challenge for their practical industrial applications. To address the issues of deep vertical damage and high material loss caused by self-focusing in laser slicing, the strategy of temporal pulse burst modulation is explored. By temporally splitting a single pulse into a series of lower-energy sub-pulses, the peak power of each sub-pulse is significantly reduced, thereby effectively suppressing this detrimental effect within the range of 1 to 16 sub-pulses investigated in this study. With 8 or more sub-pulses, this method can limit the bilateral material loss to below 15 µm, enabling wafer separation within 1 min via ultrasonic cleaning- or even immediate detachment upon modification, yielding a sliced surface with a roughness Sa of 169 nm and an overall optical transmittance of approximately 75%. When the sub-pulse numbers are set to 8, 12, and 16, the surface roughness Sa of the residual wafer can be controlled at approximately 120 nm. Based on the experimental results, this work discusses the possible mechanism by which temporal pulse modulation affects crack propagation through peak power suppression and pre-damage regulation, providing a feasible approach for high-quality laser slicing of SiC wafers.