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/Co–Mo–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–Mo–P alloy as effective substitutes for nickel.