Research on an innovation hybrid machining process for the surface polishing of SiC wafer

An innovation hybrid machining process developed by Industrial Technology Research Institute (ITRI) Taiwan is investigated for the surface polishing of 4 inch 4H-SiC wafers to enhance material removal rate (MRR) and improve surface quality. The hybrid machining process consists of two major steps, the vibration assisted ductile-mode polishing process (VADPP) and the high-efficiency large-area plasma assisted polishing process (HELP-APP). This process device has been set up by ITRI and verified experimentally. At present, a device with a processing area of a diameter of 35 cm is set up. Here the 4 inch 4H-SiC wafers are taken as experimental sample. The experimental results show that, for the VADPP compared to the traditional rough polishing process, the MRR is increased by 96 %, and, for the HELP-APP compared to the traditional chemical-mechanical polishing process (i.e. without the plasma modification process), the MRRs of C face of 4H-SiC wafer are increased about 4.83 times. Comparing with the traditional machining process, the ITRI innovation hybrid process combined with several machining technologies has obviously some advantages, such as high material removal rate, high surface quality, and high production capacity.