Correlation of SiO2 etch rate in CF4 plasma with electrical circuit parameter obtained from VI probe in inductively coupled plasma etcher

Abstract

The plasma etch process has become more difficult and longer than other processes and the etch process engineers have tried to confirm whether the results of etch process were normal by monitoring the equipment. However, it is difficult for the engineers unfamiliar with plasma to discover the parameter correlated to the real etch results, so the intuitive parameter to easily estimate the etch results is required. In this study, we focused on analyzing the correlation of the etch rates of SiO2 in CF4 plasma with electrical circuit parameters closely related to genuine plasma, which were obtained by chamber modeling and VI probe. We also introduced the intuitive parameter by combining several electrical circuit parameters to estimate the etch rate more precisely. The proposed parameter was strongly correlated to the etch rates and the coefficient of determination between the etch rates and the proposed parameter was over 0.94. We expect that using the proposed parameter can contribute to maintaining the stability of etch process.