High-quality cutting of polished single-crystal silicon by wire electrical discharge machining

We discussed a method for cutting smoothly polished single-crystal silicon surfaces by wire electrical discharge machining to obtain a high-quality surface. To cut out parts with smooth surfaces from the plates by rough-cutting in water while maintaining the initial smoothness of the surfaces, several kinds of masks were applied to the polished surfaces before cutting. It was found that although the application of resin masks is effective for obtaining smooth surfaces far from the cut section, the surface smoothness near the section cut in water is less than in the case of cutting in oil. Next, finish-cutting in oil was performed to remove cracks and chips generated by rough-cutting in oil. As a result, although a few chips were generated at edges of the cut section, cracks were successfully removed by finish-cutting, so that the surface quality was successfully improved by finish-cutting in oil.