Electrodeposition of Co-Mo-P barrier coatings for Cu/Au coated systems

By using citrate as the complexing agent, cobalt-molybdenum-phosphorus (Co-Mo-P) alloy coatings were successfully developed and electrodeposited. Coatings containing up to about 10% Mo have been produced. Coating containing 8% Mo, 20% phosphorus and Co balance have been investigated further as barrier coating. To study the diffusion property, the apparent interdiffusion coefficients of Cu/CoMo-P/Ni were determinated. The micro-profiling and Boltzmann-Matano Method were used to obtain the interdiffusion coefficients. It was found that the interdiffusion coefficients for nickel are higher than that the apparent interdiffusion coefficients of the Cu/Co-Mo-P alloys. The results have indicated the potentials of Co-MoP alloy as effective substitutes for nickel.