METHOD OF DIRECT PLATING OF COPPER ON A SUBSTRATE STRUCTURE

摘要

The present invention teaches a method for depositing a copper seed layer onto a substrate surface, generally onto a barrier layer. The barrier layer may include a refractory metal and/or a group 8, 9 or 10 metal. The method includes cathodically pre-treating the substrate in an acid-containing solution. The substrate is then placed into a copper solution that includes complexed copper ions and a current or bias is applied across the substrate surface. The complexed copper ions are reduced to deposit a copper seed layer onto the barrier layer. In one aspect, a complex alkaline bath is then used to electrochemically plate a gapfill layer on the substrate surface, followed by overfill in the same bath. In another aspect, an acidic bath ECP gapfill process and overfill process follow the alkaline seed layer process.