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

Abstract

Plasma etch process has become more difficult and longer than other processes and 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 analysing 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 modelling 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.

Analysis of the Characteristics of Radio Frequency Power Transmission Lines Using a Voltage Current Probe in Low-Pressure Discharge

“…As plasma processes become more complicated, their analysis and optimization by evaluating the equipment properties and plasma parameters have become important [8][9][10]. It is necessary to evaluate the complex interactions between plasma and external parameters and optimize plasma processes, including the tools and equipment conditions [10][11][12][13][14]. Furthermore, to conduct these measurements accurately, the accuracy and reliability of the plasma process monitoring sensor such as the voltage current (VI) sensor, should be improved [15,16].…”