Etching of platinum thin films by high density Ar/Cl2/HBr plasma

Platinum is widely researched as the electrode material for capacitor of high dielectric films in dynamic random access memory (DRAM) application However, the dry etching of Pt is difficult because of its chemical stability. So, the dry etching of Pt remains at the preliminary work. In this work, Pt etching mechanism was investigated by using inductive coupled plasma (ICP) with Ar/Cl-2/HBr gas. The peaks were found due to brominated Pt as well as chlorinated Pt in the XPS (X-ray photoelectron spectroscopy) narrow scan. Ion bombardment effects on the etched surface decreased with increasing HBr/(HBr+Cl-2) gas mixing ratio. The maximum etch rate of Pt was 105 nm/min at the HBr/(HBr+Cl-2) ratio of 0. And selectivity to SiO2 was good in all samples with various HBr/(HBr+Cl-2) gas mixing ratios. These results are consistent with XPS and OES (optical emission spectrometry) and single Langmuir probe.