ETCHING PROPERTIES OF PT THIN-FILMS BY INDUCTIVELY-COUPLED PLASMA

The inductively coupled plasma etching of platinum with Ar/Cl-2 gas ch emistries 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 i ncreases 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 se em 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. Quadr upole mass spectrometry (QMS) Is used to examine the variations of pla sma characteristics with various Ar/Cl-2 gas chemistries. QMS results show that Cl-2 molecules are converted to Cl radicals with adding Ar g as to Cl-2 plasma. QMS results support the increased atomic percentage s of Cl elements on the etched Pt surface. Single Langmuir probe measu res ion current density with various Ar/Cl-2 gas plasma. Ion current d ensities are used to investigate the ion bombardment effects on the et ched surface. Thin film thickness measuring system, scanning electron microscope and a four-point probe are used to extract the Pt etching c haracteristics. The maximum etch rate of Pt is approximately 140 nm/mi n at the Ar/(Ar+Cl-2) mixing ratio of 0.9. These results are consisten t with XPS, QMS, and Langmuir probe data. (C) 1998 American Vacuum Soc iety. [S0734-2101(98)01505-X].