Improved Self-Annealing of Copper Using Cobalt or Nickel Underlayer
Original Publication Date: 2004-Nov-16
Included in the Prior Art Database: 2004-Nov-16
The self-annealing behaviour of copper on various substrates was investigated. It was discovered that self-annealing is strongly dependent on the barrier layer the copper is deposited on. A fast and significant change in sheet resistance at room temperature was observed when depositing copper on a cobalt or nickel layer as barrier, while a smaller change was seen for traditional tantalum based barriers. This paper describes an improved copper annealing process by utilizing a copper barrier layer that promotes self-annealing. The required anneal after copper deposition to change the microstructure of copper can thereby be reduced or omitted.