Novel short-gas-residence-time electron cyclotron resonance plasma etching

Abstract

Novel short-gas-residence-time electron cyclotron resonance (ECR) plasma etching is described. Using a newly equipped high-pumping-rate etching system (5000 ℓ/s), we obtained a high etch rate and high anisotropic etching of silicon at low pressure and high gas flow rate. The residence time obtained was 30 ms. The silicon etch rate with Cl2 dramatically increased up to 1 μm/min as the gas flow rate increased to 90 sccm at 0.5 mTorr. It was proven by plasma emission measurement that the reaction products were minimized by the present method. These results indicate that the short-gas residence time produces a small amount of reaction products and a large amount of etching species.