Compact water-cooled surface wave plasma source for remote plasma cleaning

Abstract

This paper describes the design and operation of a compact surface wave plasma source for remote plasma processing [i.e., plasma enhanced chemical vapor deposition chamber cleaning, dry etching (SiO2, Si3N4, and silicon), photoresist stripping (SU-8), and decapsulation of microchips]. In order to get higher radical generation and increased industrial throughput, the source is designed to generate plasma at a high flowrate. The source is designed to be compact so that it can be more beneficial in the case of positioning multiple sources on a large processing chamber for faster radical cleaning with better uniformity. The source can operate from low to high flowrates (i.e., 100 SCCM H2 or 10 slm NF3) and provide high decomposition rates for NF3. The etching rate for SiO2 (higher than 450 nm/min) is achieved with 2.5 kW microwave power and 3-5 slm. The key advantages of the source are compactness, higher microwave coupling due to indirect water-cooling, and thereby high operating flow and decomposition rates.