Laser double-layer slicing of SiC wafers by using axial dual-focus

Silicon carbide (SiC) is a critical semiconductor material extensively used in high-performance electronic power devices. However, achieving high-efficiency, low-loss SiC substrates remains a significant challenge. This study introduces an innovative dual-focus, double-layer laser slicing technique for SiC, incorporating spherical aberration correction into the traditional weighted Gerchberg-Saxton (GSW) approach. The corrected method generates controllable dual-focus beams, which form double-layer cracks within the SiC, significantly enhancing slicing efficiency. The proposed method achieves a slicing speed twice as fast as conventional techniques. Using this approach, a 10 × 10 × 1.4mm³ SiC sample was successfully sliced into three chips with thicknesses ranging from 400 µm to 550 µm. The resulting wafers demonstrate tensile strengths of 1.07 MPa and 1.40 MPa, with surface roughness values of 0.9 µm and 0.55 µm, respectively. Raman analysis further indicates the presence of SiC structures in the processed regions using the double method. This technique showcases significant potential for broader applications in processing other transparent and brittle materials, providing what we believe to be a new pathway for high-precision laser slicing.