Dry etching characteristics of TiN thin films in CF4/BCl3/N2 plasma

In this study, we investigated the etching characteristics of TiN thin film and the selectivity of TiN to SiO2 in an inductively coupled CF4/BCl3/N-2 plasma system. The dry etching mechanism of TiN thin films was studied by varying the CF4/BCl3/N-2 gas mixing ratio, RF power, direct current (DC) bias voltage, and process pressure. The optimized process conditions were as follows: RF power of 700 W, DC-bias voltage of -100 V, process pressure of 1 Pa, and substrate temperature of 40 degrees C. The maximum etch rate of the TiN thin films was 109 nm/min with the CF4/BCl3/N-2 (2:5:15 sum) plasma. Non-volatile etching byproducts were Ti-F compounds as determined by X-ray photoelectron spectroscopy analysis. (C) 2011 Elsevier B.V. All rights reserved.