Investigation on etching characteristics of Pd thin films using CH3COOH/Ar gas

•Novel CH3COOH/Ar gas was used to etch Pd thin films.•Good etch profile with a high degree of anisotropy for Pd films was achieved.•Etch mechanism was sputter etching with surface oxidation and sidewall protection.

Inductively coupled plasma reactive ion etching of Pd thin films with TiN hard masks was carried out in a CH3COOH/Ar gas mixture. The addition of CH3COOH to Ar gas decreased the etch rate but a good etch profile with a high degree of anisotropy was obtained at 50% CH3COOH/Ar. Variations in the etch parameters showed that high inductively coupled plasma power and dc-bias voltage improved the etch profile. X-ray photoelectron spectroscopy and optical emission spectroscopy results revealed that the Pd films in CH3COOH/Ar gas followed the sputtering etch mechanism assisted by the oxidation and sidewall protection provided by polymer films.