High-Speed Etching of Silicon Carbide Wafer Using High-Pressure SF6 Plasma

Abstract

Semiconductor silicon carbide (SiC) is proposed to be a promising material for power-saving devices. However, due to its hard and brittle properties, there is a need to develop a highly efficient strain-free thinning process for the backside thinning of vertical power transistors. As a method for thinning SiC wafers without crystallographic damages, plasma etching with high-pressure SF6 plasma was proposed and the dependence of different processing parameters on the removal rate was investigated. The results revealed that the removal rate was mainly influenced by the power density and relatively insensitive to processing parameters such as processing gap and gas flow rate. It was discovered that a high-speed etching of the entire surface of a commercially available 2-inch wafer at approximately 15 μm min−1 can be achieved by increasing the radio frequency power. Additionally, it was demonstrated that the thickness of the 2-inch wafer can be thinned to approximately 100 μm by only 20 min plasma etching.