| abstract |
A method and apparatus for forming a metal interconnect is provided. A tungsten plug is first deposited by selective WCVD within a feature having an aspect ratio of 3:1 or greater to at least partially fill the feature. An IMP barrier layer is next deposited over the tungsten plug. A PVD copper seed layer followed by an ECP copper layer is then deposited over the barrier layer to fill the feature. The tungsten plug has a thickness of about 1,000 to about 5,000 angstroms and fills less than about 50% of the volume of the feature. |