Method and apparatus for preparing and metallizing high aspect ratio silicon semiconductor device contacts to reduce the resistivity thereof

Claim 1

An in situ method of cleaning and metallizing silicon contacts on a semiconductor wafer, the method comprising the steps of: placing a semiconductor wafer having silicon contacts thereon on a wafer support in a CVD processing chamber; flowing into the chamber and across the wafer on the support a cleaning gas consisting essentially of a gas mixture of hydrogen and argon in which the hydrogen content is between 20 percent and 80 percent by volume and at a pressure of between 1 mTorr and 10 Torr; coupling medium frequency RF energy into the chamber with an energy source connected between the water support and an electrode extending parallel to the wafer support and energizing a plasma in the cleaning gas therewith to clean the silicon contacts on the wafer; supplying high frequency RF energy, controllable separately of the medium frequency RF energy, to the wafer support and biasing a wafer on the support therewith; and heating the wafer on the support to a temperature of at least 400° C.; then, introducing into the chamber a reactant gas containing titanium while heating the wafer on the support to produce a CVD reaction and depositing a titanium or a titanium compound film thereby onto the wafer.