SELECTIVE ELECTROLESS NI DEPOSITION ONTO PD-ACTIVATED SI FOR INTEGRATED-CIRCUIT FABRICATION

Selective electroless Ni deposition on Pd-activated Si was investigated for the fabrication of a high density and uniform metallization of complementary metal oxide-semiconductor devices. The resistance of conductor patterns was reduced by a factor of 20 with Ni cladding of polycrystalline lines after an annealing cycle to 400-degrees-C for 30 min in an N2 atmosphere. For this annealing cycle the diffusion of Si and Pd into Ni films was investigated by X-ray microanalysis and secondary ion mass spectroscopy. The fine-grained structure of annealed electroless Ni deposits on Si surfaces was observed by scanning electron microscopy investigation. The most challenging issues of selective electroless Ni deposition on Pd-activated polycrystalline lines are the intense growth of Ni films at the edges of lines and Ni deposition between the lines.