CO2-3对羟基乙叉二膦酸镀铜液的影响

研究羟基乙叉二膦酸(HEDPA)镀铜液中CO2-3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CO2-3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, CO2-3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.

Influence of CO2-3 on Copper Electrodeposion from 1-Hydroxyethylidene-1,1-diphosphonic Acid Baths

The effect of CO2-3 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 CO2-3 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 CO2-3 to (111) plane containing more CO2-3. The IR spectra of the solid complex purified from the bath showed that CO2-3 could enter the complex and stabilize Cu2+ in the structure as the second ligand, so the potential of copper deposition was negatively shifted and the (111) plane orientation was preferred.