Sidewall-Fence-Free Pt Etching with an Ar/O2 Mixed Gas Plasma

Platinum has been successfully patterned with a TiN mask in an Ar/O2 plasma.No fence residue was observed on the etched Pt pattern if the thickness of the TiN mask was less than 300 nm. During the etching process, titanium dioxide and platinum oxides were formed and redeposited on the mask and the Pt structure in the Ar/O2 plasma according to Auger and XPS analyses. The etch rates of Pt and TiN films decreased with increasing oxygen concentration in the Ar/O2 gas mixture. The addition of O2 inthe gas mixture could improve the sidewall slope of the etched Pt structure. This was ascribed to redeposited platinum oxides and TiO2 on the sidewall, which makes the sidewall more resistant to ion etching at a higher concentration of oxygen.