Abstract
The relationship between microstructure of tungsten thin films and plasma etching properties has been studied. Rutherford backscattering, nuclear reaction analysis 16O(α,α)16O, X-ray diffraction, and resistivity measurements have been used to characterize the sputter deposited films. Independent of deposition pressure, the films were all high density, low oxygen (<1 at%), low resistivity and bccot-phase. Etch rate differences of 40% were measured in pure SF6, whereas only 10% differences were seen in SF6/Cl2 and SF6/O2BCi3 plasmas. Intentional oxygen doping (up to 2 at-%) increases the etch rate in pure SF6 plasma by 75%, wherasthe etch rate in SF6/O2/BCl3 plasma only increases 25%. The role of film density (porosity) and oxygen incorporation on etching mechanism are discussed.
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Franssila, S., Molarius, J.M. & Saarilahti, J. Plasma Etching Characteristics of Sputtered Tungsten Films. MRS Online Proceedings Library 260, 341–346 (1992). https://doi.org/10.1557/PROC-260-341
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DOI: https://doi.org/10.1557/PROC-260-341