The dry etching of tin thin films using inductively coupled CF4/Ar Plasma

Abstract

In this study, we changed the input parameters (gas mixing ratio, RF power, DC bias voltage, and process pressure), and then monitored the effect on TiN etch rate and selectivity with SiO2. When the RF power, DC-bias voltage, and process pressure were fixed at 700 W, - 150 V, and 15 mTorr, the etch rate of TiN increased with increasing CF4 content from 0 to 20 % in CF4/Ar plasma. The TiN etch rate reached maximum at 20% CF4 addition. As RF power, DC bias voltage, and process pressure increased, all ranges of etch rates for TiN thin films showed increasing trends. The analysis of x-ray photoelectron spectroscopy (XPS) was carried out to investigate the chemical reactions between the surfaces of TiN and etch species. Based on experimental data, ion-assisted chemical etching was proposed as the main etch mechanism for TiN thin films in CF4/Ar plasma. © 2013 KIEEME. All rights reserved.