Electrochemical Cu Nanoparticle Deposition on TaSiN Diffusion Barrier Films

High-density Cu nanoparticles were spontaneously deposited on TaSiN diffusion barrier layers using organic solutions.These activated surfaces were then plated with Cu using electroless deposition.The organic deposition solution was composed of conventional solvent extractants that are very poor electrolytic conductors but can sustain short range spontaneous reactions.The process proceeds by an electrochemical displacement mechanism and effective Cu seed layers could be obtained at 35°C in 10 to 20 s.Additives consisting of low formula weight organics were used to enhance the Cu nanoparticle deposition.Other operating procedures, such as substrate etching, solution concentration, additives, agitation, and deposition time, were evaluated to determine their effects on particle density, morphology, and uniformity.The Cu-seeded TaSiN surfaces were then built up using a standard electroless Cu process.A continuous, pore free, smooth, and adherent Cu film was attained after 2 min of electroless deposition.