Chemical Reaction on Etched TaNO Thin Film as O-2 Content Varies in CF4/Ar Gas Mixing Plasma

Abstract

In this work, we investigated the etching characteristics of TaNO thin films and the selectivity of TaNO to SiO2 in an O-2/CF4/Ar inductively coupled plasma (ICP) system. The maximum etch rate of TaNO thin film was 297.1 nm/min at a gas mixing ratio of O-2/CF4/Ar (6: 16: 4 sccm). At the same time, the etch rate was measured as a function of the etching parameters, such as the RF power, DC-bias voltage, and process pressure. X-ray photoelectron spectroscopy analysis showed the efficient destruction of the oxide bonds by the ion bombardment, as well as the accumulation of low volatile reaction products on the etched surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism for the CF4-containing plasmas.