Influence of Tungsten Sputtering Target Density on Physical Vapor Deposition Thin Film Properties
Authors: Lo, Chi-Fung; McDonald, Peter; Draper, Darryl; Gilman, Paul
Source: Journal of Electronic Materials, Volume 34, Number 12, December 2005 , pp. 1468-1473(6)
Abstract:Tungsten (W) is commonly used for diffusion barrier, via, and gate material in semiconductor devices. In order to achieve the desired properties and minimize particle generation, control of the sputter target properties, which include density, purity, grain size, and orientation, are essential. This study focused on the effect of sputtering target density on the thin-film properties and defect generation. By controlling the powder sintering process, three sputtering targets from 82.5% to 99.5% of theoretical density were prepared. By physical vapor deposition (PVD), about 1600 Å thin films were deposited onto the silicon wafers. The deposited films were then evaluated by four-point probe, x-ray diffraction (XRD), and scanning electron microscope (SEM) to determine the influence of target density on the deposited film properties. In addition to film properties, the erosion morphology on the sputtered surface was also investigated by SEM. The voids are known to be the potential particle sources from the target. By monitoring the generation of voids, the correlation between target density and potential particle sources was established.
Document Type: Research Article
Publication date: December 1, 2005