Spectroscopic and Electrochemical Analysis of Cu(I) Complex of Copper Sulfate Electroplating Solution and Evaluation of Plated Films

摘要

In this study, we investigated a behavior of cuprous ion (denoted as Cu(I)) in the copper sulfate plating solution and effects of the Cu(I) on a quality of Cu plating film. Through spectroscopic method, two kinds of holding structure of Cu(I) in the plating solution were firstly indicated by analyzing the kinetics of complex forming reaction between the Cu (I) and bathocuproinedisulfonic acid, disodium salt (BCS). One component is ignited from Cu(I) probably incorporated into deep inside of polyethylene glycol (PEG), and the Cu(I) must have steric hindrance of PEG to be interacted with the BCS in plating solution. Another one is a component for Cu(I) which can be instantaneously reacts to the BCS to be complex. In addition, interestingly, it has been shown that instantaneous component is affecting the roughness of Cu plating film. These results indicate that spectroscopic measurement and analysis is effective for the management and evaluation of the plating solution for high quality production.