Precision laser slicing technology for single-crystal SiC wafer: 4th Report : High-speed and high-stability slicing by nanosecond laser

We investigated the use of a short-pulse laser to achieve high-speed and high-stability laser slicing of SiC. The short-pulse laser was effective in achieving high-speed slicing by promoting internal modification through heat effects and by expanding the area of cleavage extension. However, excessive cleavage linkage along the off-angle was shown to cause instability of peeling. To achieve higher speed and stable peeling, we proposed a method combining control of the laser irradiation interval with control of the laser scanning direction to achieve uniform cleavage linkage. We succeeded in controlling the peeled surface structure to have step-like unevenness along the off-angle in an orderly manner, and also in suppressing excessive cleavage linkage. Based on these basic experiments, we successfully achieved slicing of a 2-inch wafer. The surface was controlled to have a uniform step structure. The processing speed was approximately 24 times faster than using an ultrashort-pulse laser, achieving both high speed and high stability.