Dry etching of TaN thin film using CH4/Ar inductively coupled plasma

In this research, we investigated the TaN etch rate and selectivity with under layer (HfO2) and mask material (SiO2) in inductively coupled CH4/Ar plasma. As the CH4 content increased from 0% to 80% in CH4/Ar plasma, the TaN etch rate was increased from 11.9 to 22.8 nm/min. From optical emission spectroscopy (OES), the intensities for CH [431 nm] and H [434 nm] were increased with the increasing CH4 content from 0% to 100% in CH4/Ar plasma. The results of x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) showed no accumulation of etch by-products from the etched surface of TaN thin film. As a result of OES, AES and XPS analysis, we observed the etch by-products from the surfaces, such as Ta–N–CH and N–CH bonds. Based on the experimental results, the TaN etch was dominated by the chemical etching with the assistance of Ar sputtering in reactive ion etching mechanism.

► In this research, we investigated the TaN etch rate and selectivity with under layer (HfO2) and mask material (SiO2) in inductively coupled CH4/Ar plasma. ► The results of X-ray photoelectron spectroscopy and Auger electron spectroscopy showed no accumulation of etch by-products from the etched surface of TaN. ► Based on the experimental results, TaN etch was dominated by the chemical etching with assistance by Ar sputtering in reactive ion etching mechanism.