化学銅メッキ (III) 析出速度に及ぼす基本条件の影響

Abstract

Effects of fundamental plating conditions on copper deposition rate were investigated by means of gravimetric method and the results were discussed by the total current-potential curves determined under various conditions.E-I curves were determined by potentio-kinetic method with scanning rate of 10mV·s-1.pH of the solution had the greatest effects on the deposition rate, and the effects of the concentration of copper salt or formaldehyde was less than the former.In general, the behavior of total current-potential curve was fairly agreed with the expected fundamental behaviors of local anode and cathode reactions reported previously. Some disagreement was fond in the behavior of cathode reaction, which was considered to be due to the interaction between copper complex ion and formaldehyde to the solution.It was made clear that agitation of the solution, in the state of free from soluble oxygen, increased deposition rate.On the other hand, agitation of the solution in the air-saturated state, made the deposition rate somewhat less, which was considered to be caused by the increase of diffusion current of soluble oxygen resulting in the decrease of the efficiency of cathode reaction.The effects of stability of the solution by agitating in the air-saturated state may be explained as follows: the increase of diffusion rate of soluble oxygen inhibits Cu2O (formed by homogeneous reaction) from reduction to active Cu nucleus which accelerates decomposition reaction.