An electrochemical model for prediction of microvia filling process

Abstract

The microvia filling process as encountered in the multi-layered printed circuit board manufacturing industry was investigated by electrochemical measurement and a multi-physics coupling technique in this paper. The effect of an accelerator on filling performance was investigated by cathode polarisation curves to obtain the suitable copper electroplating conditions. In the model, mass balance of adsorbed additives as a result of cathode surface shape change was considered. The electrodeposited layer thickness in the microvia from the additive-free solution and additive-assisted solution was calculated by the finite element method. The void-free microvia filling was finally achieved in acid copper electroplating solution consisting of base electrolyte, 200 ppm ethylene oxide–propylene oxide co-polymer and 1 ppm bis-(sodium-sulphopropyl)-disulphide, which was validated by experimental results.