Induction-Diffusion-Adsorption Process of Malachite Green for Cobalt Superconformal Electrodeposition

Abstract

Cyclic voltammetry (CV), chronopotentiometry and quartz crystal microbalance were used to study the effect of Malachite Green (MG) on bottom-up growth of cobalt. The addition of MG not only inhibited the reduction of Co2+ but also accelerated the hydrogen evolution process. The metal reduction process was enhanced as well as the current efficiency was higher with the increase of pH. The bottom-up growth of cobalt can be achieved with the potential of -1.20V. Induction-diffusion-adsorption superconformal electrodeposition mechanism was proposed to illustrate the synergistic effect of MG and pH on the growth of cobalt. On one hand, the MG concentration gradient and pH gradient could be formed to achieve a growth rate difference within blind vias so as to obtain bottom-up growth (diffusion-adsorption effect). On the other hand, the growth rate difference was intensified due to the accelerating effect of MG on HER so as to boost the cobalt superfilling (induction effect).