Etch characteristics of Pt using Cl-2/Ar/O-2 gas mixtures

Inductively coupled plasma etching of platinum with Cl-2/O-2/Ar gas chemist ries was examined. Plasma characteristics were investigated with increasing O-2 ratios using a Langmuir probe and a quadrupole mass spectrometer. The chemical reaction during the platinum etching was also examined from the ch emical binding states of the etched surface by X-ray photoelectron spectros copy. Additional characterization employed a four-point probe, thin-film th ickness measuring system, and scanning electron microscopy. The relationshi p between plasma characteristics and etch results with various O-2-gas mixi ng ratios was also studied. It was confirmed that small additions of oxygen into the Cl-2/Ar gas mixtures lead to high selectivity and a good sidewall profile without a fence, also referred to as a bull-ear. (C) 2000 The Elec trochemical Society. S0013-4651(99)09-040-0. All rights reserved.