Slicing of 150 mm silicon carbide wafers using wire-EDM with energy-based discharge control

Silicon carbide (SiC) is characterized by its hardness and brittleness, making wafer fabrication particularly challenging and time-consuming. In conventional wire electrical discharge machining (WEDM), the enlargement of workpiece dimensions often increases the discharge area, resulting in unstable discharges and inefficient chip removal, thereby prolonging the overall processing time. Enhancing discharge stability and chip evacuation efficiency has thus become a key research focus in WEDM for hard materials like SiC. This study investigates the slicing of 150 mm (6-inch) SiC wafers using optimized WEDM parameters, with an emphasis on improving chip evacuation at the center of the wafer and utilizing varying discharge energy levels. Experimental results indicate that high-energy cutting yielded a wafer thickness of 1 mm, while low-energy discharge enabled slicing down to 0.49 mm. Surface characteristics, including uniformity, curvature deviation (SORI), and overall bow (BOW), were evaluated. The findings reveal that higher discharge energy led to more pronounced discharge craters and wire breakage marks on the wafer surface. In contrast, lower energy cutting produced visibly smoother and more uniform surfaces. Measurements further showed reduced SORI and BOW values under low-energy discharge conditions.