Influence of Deposition Variables on LPCVD Tungsten Films Deposited by the WF sub 6 /Si Reduction

摘要

In an effort to isolate and study the Si reduction of WF sub 6 by the reduction reaction 2 WF sub 6 + 3 Si -> 2 W + 3 SiF sub 4 , a systematic study of the influence of temperature, substrate doping, deposition time and variable flow rates of tungsten hexafluoride (WF sub 6 ) was conducted. The effect of varying these parameters on film thickness, layer resistivity, encroachment and adhesion was investigated. A set of operating conditions has been defined that yield stable, adherent, self-limiting films of -100A thickness that are free from encroachment. Film quality was found to be relatively insensitive to moderate variations in process parameters, a favorable indication in terms of process integration and manufacturability. (ERA citation 11:009191)