Monday, August 20, 2018

Overview of Applied Materials cobalt metallization for local interconnects

For those of you interested in the details behind the Applied Materials integrated cobalt metallization process Jonathan Bakke has written two informative blogs about it in Semiconductror Engineering:

(1) The Role Of Cobalt In Enabling AI - For continued performance, power, area and cost improvements, materials need to be engineered at the atomic scale.
(2) The Materials Side Of AI - What comes after tungsten fill for contacts and copper for the lowest-level interconnects?
The integrated cobalt solution using Applied Materials platforms (Applied Materials).

Jonathan Bakke is global product manager for Contact and Middle of Line Products in the Metal Deposition Products Business Unit at Applied Materials. He details the process flow and tool sets from Applied Materials involved in the complete BEOL Co metallization flow:

  • PVD titanium and ALD titanium nitride for the silicide and barrier layers
  • PVD cobalt serves as an anchor layer to ensure good cobalt adhesion to the bottom of the feature
  • CVD cobalt is then used to deposit a conformal film to bulk fill the feature
  • Anneal purifies and reflows the cobalt, removes the CVD seam, and merges crystal grains to form a more crystalline, lower resistance material
  • PVD cobalt for a thick overburden film
  • CMP removes overburden materials to create a smooth planar surface
  • E-beam technology monitors the process and detects voids