Etch process for improving yield of dielectric contacts on nickel silicides

Abstract

The embodiments of the invention generally relate to an etching process, and more particularly to an etch processing for improving the yield of dielectric contacts on nickel silicides. An oxygen-free feedgas is used in an etching process to reduce or eliminate residuals, including oxidation and consumption of the silicide layer, at the contact surface. The contact resistance at contact surface is reduced, thereby improving the performance of the device

1 . A semiconductor wafer, comprising:
 a substrate;   a silicide layer on the substrate;   an insulation material on the silicide layer having exposed portions to the silicide layer wherein the exposed portions are etched using an oxygen-free feed gas and are substantially free of a residual layer; and   a contact material layer on the insulation material such that the contact material layer is in contact at least one exposed portion of the silicide layer.   
   
   
       2 . The semiconductor wafer of  claim 1 , further comprising providing a second contact material layer on the insulation layer such that the second contact material layer is in contact with at least another of the exposed portions of the silicide. 
   
   
       3 . The semiconductor wafer of  claim 1 , where the silicide layer comprises nickel silicide. 
   
   
       4 . The semiconductor wafer of  claim 1 , wherein the dielectric material comprises silicon nitride. 
   
   
       5 . The semiconductor wafer of  claim 1 , wherein the oxygen-free feed gas consists essentially of nitrogen. 
   
   
       6 . The semiconductor wafer of  claim 3 , wherein a portion of the nickel silicide layer is exposed through the insulation and the contact material layer on the insulating material contacts the exposed portion of the nickel silicide layer. 
   
   
       7 . The semiconductor wafer of  claim 1 , wherein the feed gas comprises nitrogen in a range of about 0% to about 80% by volume. 
   
   
       8 . The semiconductor wafer of  claim 1 , wherein the feed gas comprises nitrogen in a range of about 25% to about 45% by volume. 
   
   
       9 . The semiconductor wafer of  claim 1 , wherein the feed gas comprises hydrogen in a range of about 0% to about 80% by volume. 
   
   
       10 . The semiconductor wafer of  claim 1 , wherein the feed gas comprises hydrogen in a range of about 5% to about 15% by volume.