三乙醇胺对羟基亚乙基二膦酸镀铜液的影响研究

Influence of Triethanolamine on Copper Electrodeposition from 1-Hydroxyethylene-1,1-diphosphonic Acid Electrolyte

研究羟基亚乙基二膦酸(HEDPA)镀铜液中三乙醇胺(TEA)对铜还原和氧化过程的影响.用Hull Cell测试阴极电流密度分布,通过电位扫描、循环伏安和交流阻抗研究铜沉积的电化学行为,通过镀液的吸光度测试和固体配合物的红外光谱分析推断配位化合物的形式.结果表明:TEA的加入能够扩大HEDPA镀铜体系的阴极允许电流密度,对铜电沉积有阻化作用,促进铜阳极溶解,并可抑制氢气的析出;随着溶液中TEA浓度增加,在玻碳电极上发生的铜还原过程由电化学控制逐渐转变为扩散控制,可获得结晶细小、表面平整的致密铜镀层.TEA的加入,主要是在HEDPA镀铜体系中形成CuTEA(OH)2配位化合物,并吸附在电极表面而影响电化学反应.

The effect of triethanolamine（TEA） on reduction and oxidation process of copper in 1-hydroxyethylene-1,1-diphosphonic acid（HEDPA） electrolyte was studied.The distribution of cathode current density was checked by using Hull Cell.Electrochemical measurements,such as cyclic voltammetry,electrochemical impedance spectroscopy and potentiodynamic polarization technique,were employed to investigate the electrochemical behavior of copper deposition.The IR spectra of the complex and the absorbance curves of the electrolyte were used to characterize the coordination compounds.The introduction of TEA enhances cathode current density of the HEDPA electrolyte,suppresses electrodeposition of the copper,promotes the dissolution of copper anode,and inhibits the liberation of hydrogen.In the low-TEA-concentration electrolyte,the reduction process of copper at a glassy carbon electrode was controlled by electrochemical mechanism.With increasing the TEA concentration,diffusion mechanism gradually becomes to control the reduction process of copper,meanwhile,an even and compact copper coating for the fine grains was obtained.The introduction of TEA in the HEDPA electrolyte induces formation of the CuTEA（OH）2 coordination compounds.The formed CuTEA（OH）2 coordination compounds adsorb on the electrode surface,which influences the electrochemical reaction.