ProcessesSiC via hole etching for GaN HEMT

Result of via hole processing for contact from the back side of SiC substrate to electrode by ICP etching system. In order to facilitate metal embedding, the hole openings are made in a progressive tapered shape. While high rates are required for SiC via-hole etching, it is also necessary to reduce damage to the device and suppress the rise in sample temperature. Since the sample is attached to the SiC substrate with resin, etching at a temperature below the heat resistance of the resin is required. Here, high-speed etching of 1.3 μm/min is achieved anisotropically with the wafer temperature below 150°C.