Basic Experiment on Atmospheric-Pressure Plasma Etching with Slit Aperture for High-Efficiency Dicing of SiC Wafer

Abstract

Silicon carbide (SiC) is a promising semiconductor material for high-temperature, high-frequency, high-power, and energy-saving applications. However, because the hardness and chemical stability of SiC are high, few conventional machining methods can handle this material efficiently. We previously developed a plasma chemical vaporization machining (PCVM) technique, which is an atmospheric-pressure plasma etching process, and investigated its application to the processing of SiC substrates. In this paper, we propose a novel style of PCVM technique for dicing, using slit apertures to confine the plasma. From experiments by means of an apparatus with a one-slit aperture formed by two masks, it was found that the kerf loss was almost proportional to the slit width, and that the etching depth increased with RF power. Furthermore, from experiments on a SiC wafer, we obtained a 130-μm etching depth and 300-μm kerf loss for an 11-min processing time and 200-μm slit width.