The magnetization frequency dependence of enhanced inductively coupled plasma

The enhanced ICP (E-ICP) etcher with various magnetization frequency of external coil current has shown improved etch characteristics in silicon dioxide etch with CF4 gas, and it improves the etch rate of silicon dioxide with the C4F8 gas also. It has better improvement in etch rate at low pressure process for C4F8 gas; approximately 80% at 1.33 Pa (10 mtorr) and 30% at 2.66 Pa (20 mtorr). We compared the magnetization frequency dependence of etch rates for three different types of gas parameters, C4F8 gas with 60% of Ar gas, C4F8 gas only, and CF4 gas. Time-resolved measurements were accomplished for Ar plasma to have better perspective of the E-ICP operation. Improvement of etch characteristics is expected when the E-ICP frequency resonates to a lifetime of some desirable states. Further refined analysis of E-ICP with time-resolved measurement would explain the reasons of improvement in etch characteristics.