Experimental Study of SiO2 Sputter Etching Process in 13.56 MHz rf-Biased Inductively Coupled Plasma

Abstract

Inductively coupled plasma (ICP) has been widely used in semiconductor manufacturing, especially in nanoscale etching and deposition process. It is important to understand the relationship among the 13.56[Formula: see text]MHz rf-biased power and the etching process. In this study, the effect of dual rf power on the SiO2 sputter etching is investigated by measuring the ion energy distributions (IEDs), ion flux and sputter etching rate. The results show that the IEDs transforms from uni-modal towards bi-modal distribution when rf-biased power is applied to electrode. The influence of source power, bias power, discharge pressure and current ratio on the ion flux, IEDs are investigated in detail. The energy separations measured by RFEA are in good agreement with analytical model. The ion flux can be modulated by the 13.56[Formula: see text]MHz rf-biased power. Moreover, the coil current ratio expands the control window of the ion bombardment energy for the ICP etch equipment while. Finally, an ion-enhanced etching model is introduced to obtain the sputter etching rate and reveals the influence of discharge conditions on the etch rate.