By performing a re-sputter process during the formation of a barrier layer
for a contact opening in a tungsten-based process, the reliability of the
tungsten deposition, as well as the performance of the resulting contact
plug, may be enhanced. During the re-sputtering process, a thickness of
the titanium-based barrier layer may be reduced at the contact bottom,
while at the same time the material is re-condensed on critical lower
sidewall portions of the contact opening.