A new microwave-excited plasma etching equipment for separating plasma excited region from etching process region

A new microwave-excited plasma etching equipment has been developed. The equipment adopts a low-electron temperature and high-density plasma source using a radial line slot antenna and a newly developed metal shower head for etching gas supply into the low-electron temperature diffusion plasma region in order to control the decomposition of gasses. Ion flux and ion energy to a wafer can be individually controlled by adjusting the microwave power applied to the antenna and the rf power applied to the wafer stage. Contact holes of 100 nm wide in SiO₂ were successfully etched using C₅F₈. Etching selectivity to the resist was improved by introducing C₅F₈ into the etching process region using the gas shower head, which indicates that excess decomposition of C₅F₈ is suppressed.