CO_3^(2-)对羟基乙叉二膦酸镀铜液的影响

Influence of CO_3^(2-) on Copper Electrodeposion from 1-Hydroxyethylidene-1,1-diphosphonic Acid Baths

研究羟基乙叉二膦酸(HEDPA)镀铜液中CO23-含量对电沉积时阴、阳极过程及镀层的择优取向的影响.通过分析阴、阳极的动电位极化曲线,发现镀液中逐渐加入的CO23-提高了阴极的极化,使电结晶晶粒细化,直至达到稳定;同时促进了铜阳极的溶解.而X射线衍射(XRD)结果表明,铜镀层的晶面择优取向从(222)逐渐向(111)转变.通过镀液中固体络合物的红外光谱分析表明,CO23-的加入以第二配体的方式进入该镀液的放电络合离子结构中,参与Cu2+的络合,形成更稳定的络合物,从而导致铜沉积电位负移,镀层(111)晶面取向增强.

The effect of CO3^2- on copper electrodeposits from 1-hydroxyethylidene-1,1-diphosphonic acid （HEDPA） baths was investigated over a wide range of concentration by electrochemical measurements, XRD, and IR spectra of the complex. It could be seen from potentiodynamic polarization curves that CO3^2- in the bath could not only enhance the cathodic polarization but also promote anodic dissolution. The X-ray diffraction results indicated the changing of preferred orientation of the copper deposits, from a preferential growth orientation （222） plane containing little CO3^2- to （111） plane containing more CO3^2-. The IR spectra of the solid complex purified from the bath showed that CO3^2- could enter the complex and stabilize Cu^2＋ in the structure as the second ligand, so the potential of copper deposition was negatively shifted and the （111） plane orientation was preferred.