Selective electroless copper deposition on aluminum nitride substrate with patterned copper seed layer

A novel process is presented for the formation of well-defined and fine copper pattern with reliable bonding onto a smooth aluminum nitride substrate by selective electroless deposition of copper in fully additive-based manner without any costly instruments and materials. The process relies on patterning CuO overlayer by photolithographic method and reducing CuO to metallic copper followed by immersing in electroless copper plating bath. The CuO overlayer is composed of the corresponding nanosized particles that allow us to etch them smoothly and selectively. The patterned metallic copper overlayer having chemical interaction with the substrate can act as seeds for initiation of electroless deposition. The minimum width of copper pattern obtained was 25 μm.