Application of Fluid Simulation in High-Speed Copper Sulfate Plating Using a Jet Flow Device

Abstract

Copper has excellent properties that include malleability and conductivity. Therefore, it is used widely in the electronics field. Copper sulfate plating is expanding further in applications that require thick deposits such as heat dissipation boards and bumps for stress relaxation during semiconductor packaging. To improve productivity and to reduce costs in this field, high-speed electroplating using high current density is desirable. For this study, a jet flow device was used for high-speed plating. Furthermore, the plating solution flow and metal ion diffusion were predicted by simulation using the computational fluid dynamics（CFD）. Correlation with actual plating behavior was investigated. Velocity distribution analysis of the chamber of a jet flow device confirmed that the plating solution was spread uniformly on the cathode surface. From results of the temperature distribution simulation in the chamber, the supplied amount of copper ions was predicted using the similarity relation of temperature diffusion and mass diffusion. The simulation results coincided with actual plating conditions and predicted the appropriate stirring speed for the copper ion concentration in the plating solution.