An optimized high pressure tungsten process for VLSI interconnect and plug applications

A manufacturable blanket CVD-W process developed to satisfy the fill properties required for plug formation, as well as the bulk resistivity and reflectivity properties needed in order to use tungsten as first metal, is described. The optimized process provides low contact resistivity to both doped polycrystalline silicon and silicides. A discussion is presented of effects of process parameters (namely temperature, gas ratios, and flow rates) for a chemical vapor deposition of tungsten on the resultant film properties and contact resistance. It is shown that deposition temperature has the greatest effect. An inverse relationship is noted between contact resistance and temperature