化学镀铜过程混合电位本质的研究

In situ Investigation on the Behavior of Mixed Potential in Electroless Copper Plating

现场测量了铜基和陶瓷基化学镀铜过程混合电位-时间曲线(Emix-t),成功地检测到了化学镀诱发过程.考察了添加剂和络合剂的浓度以及pH值对Emix-t曲线的影响,结合阴、阳极极化曲线及双电层理论对各种影响因素进行了讨论.新生铜活化的铜基化学镀铜的诱发过程是一个缓慢激活过程,所对应的Emix-t曲线是一个稍微倾斜的台阶,这不同于钯活化的基体的诱发过程.通过对不同活化工艺的Emix-t曲线的比较,发现较高的活化温度能明显减少活化时间,而且还可加速诱发过程,从而提高化学沉积铜的速度.

The mixed potential as a function of time was measured during the electroless copper plating on ceramic and copper substrates, and the induction process was determined successfully. The effects of the chelating agents, additives and pH value on the mixed potential-time curves were investigated. The results indicate that the mixed potential-time curves shift in negative direction and the induction time becomes longer with increasing concentration of the chelating agents or the additives in the solution. And higher pH values in the solution can shorten the induction time and make the potential-time curves more negative. The activation process can affect the induction time, higher activation temperature decreases the induction time greatly and increases the plating rate at the same time. It needs much longer induction time for plating copper on fresh copper activated copper substrate than that on the Pd activated copper substrate. On the basis of these results, we furthermore explained the reason why non noble metal activation process is inferior to noble metal activation process in electroless copper plaing.