Dry Etching of PZT Films with CF4/Ar High Density Plasma

Abstract

AbstractLead-Zirconate-Titanate (PZT) films were etched with CF4/Ar mixed gases in high-density plasmas. Etch characteristics of the PZT film were investigated by using in-situ plasma diagnostic tools in conjunction with the surface analysis after etching. Densities of ionic species such as F+ and CFx+(x=1∼3) and their ion energy distributions within the plasma were measured by a mass spectrometer. Characteristics of the CF4/Ar plasma were obtained by using Langmuir probe measurements. Etch rate of the PZT film was sharply increased up to a peak at 30 % CF4 as the gas ratio of CF4/(Ar+CF4) increased, and then was gradually decreased. After etching, the surface of PZT film was covered with fluorine that was bonded chemically with underlying PZT film. Ion assisted etching mechanism for the PZT was proposed and its validity was confirmed by using the results of the plasma diagnostics.