The dry etch behavior of Pt films using a TiO2 hard mask was investigated with an O2/Cl2/Ar gas chemistry in an inductively coupled plasma. The variations in etch rates and etch profiles of both the Pt films and the TiO2 masks were examined as a function of Cl2 and O2 concentration. It was found that the ratio of O2 to Cl2 concentration strongly influenced the etch selectivity of the Pt film relative to the TiO2 mask. X-ray photoelectron spectroscopy indicates that the addition of O2 to the gas mix causes a decrease in the TiO2 etch rate as a result of the oxidation of Ti2O3 and TiO species. It is proposed that these oxides arise via the reduction of TiO2 in the presence of a Cl2/Ar plasma. A 1 μm ×1 μm minimum feature size was successfully etched with this TiO2 mask material, yielding a sidewall of approximately 75° in slope that did not exhibit redeposition or residue.

This content is only available via PDF.
You do not currently have access to this content.