Precision slicing of single-crystal SiC using extremely fine fixed-abrasive diamond wire

Abstract

Single-crystal SiC is an important material for high-power semiconductors, optoelectronic applications because of its good material properties. Compared with silicon, SiC is harder and more difficult to slice, although high precision slicing process is required for a thinner slicing width. A SiC ingot is conventionally sliced using a fixed-abrasive diamond wire, where the core wire diameter is wide approximately 160 μm and diamond grain size is 20 μm. In this study, precision slicing tests were performed for single-crystal SiC by using an extremely fine diamond wire which was a half width of the conventional one. The used diamond wire had two types of core wire diameter, 60 μm and 80 μm, and the grain size was 5-10 μm and 6-12 μm, respectively. The diamond wire was driven in a single direction at a high speed of 1750 m/min. The slicing width, chipping width, workpiece surface roughness, slicing force and diamond protrusion after slicing were investigated experimentally, and a diamond blade which was usually used for slicing SiC was adopted for comparison. During slicing, the Ni plating that covered the diamond grains on the wire was partially removed which maintained the sharp protrusion of the diamond grain. The results showed that by using the proposed extremely fine diamond wire, the chipping width was significantly lowered and the normal slicing force was stable and low. Furthermore, the present study provides high-precision continuous slicing without interval dressing of the diamond wire.