In this paper, we showed how incorporation of Co and W into the surface layer of TaN can be used to control morphology of deposited Cu. In particular we show how a preference for 2D vs 3D stability is driven by the competition between Cu-substrate and Cu-Cu interactions. Using static geometry relaxations and aiMD calculations at finite temperature, we determined that 3D growth of Cu should be inhibited and wetting of Cu should be promoted in the following compositions: 25% Co-doping, 25% W-doping, 50% Co doping (in the more favourable dopant distribution) and 100% W-doping. Interestingly, two Co-TaN compositions are thermally unstable: the 100% and the less favourable 50% Co-TaN TaN surfaces as a result of the ionic radius mismatch between Co and Ta.