Etching properties of Pt thin films by inductively coupled plasma

The inductively coupled plasma etching of platinum with Ar/Cl-2 gas chemistries is described. X-ray photoelectron spectroscopy (XPS) is used to investigate the chemical binding states of the etched surface with various Ar/(Ar+Cl-2) mixing ratios. Atomic percentage of Cl element increases with increasing Ar/(Ar+Cl-2) mixing ratio with the exception of Ar/(Ar+Cl-2) mixing ratio of 1. At the same time, the peaks that seem to be subchlorinated Pt at XPS narrow scan spectra are found and Cl-Pt bonds rapidly increase at Ar/(Ar+Cl-2) mixing ratio of 0.62. Quadrupole mass spectrometry (QMS) Is used to examine the variations of plasma characteristics with various Ar/Cl-2 gas chemistries. QMS results show that Cl-2 molecules are converted to Cl radicals with adding Ar gas to Cl-2 plasma. QMS results support the increased atomic percentages of Cl elements on the etched Pt surface. Single Langmuir probe measures ion current density with various Ar/Cl-2 gas plasma. Ion current densities are used to investigate the ion bombardment effects on the etched surface. Thin film thickness measuring system, scanning electron microscope and a four-point probe are used to extract the Pt etching characteristics. The maximum etch rate of Pt is approximately 140 nm/min at the Ar/(Ar+Cl-2) mixing ratio of 0.9. These results are consistent with XPS, QMS, and Langmuir probe data. (C) 1998 American Vacuum Society. [S0734-2101(98)01505-X].