聚二硫二丙烷磺酸钠在二元络合化学镀铜体系中的作用

用电化学方法研究添加剂聚二硫二丙烷磺酸钠(SPS)对乙二胺四乙酸(EDTA)/四羟丙基乙二胺(THPED)二元络合化学镀铜过程的影响,测量体系的混合电位-时间关系,加入SPS后混合电位负移,负移过程较平缓,无突跃现象;采用线性扫描伏安法研究体系,表明SPS促进了阴阳两极的极化,但主要是影响甲醛氧化的阳极极化过程.SPS也因此一定程度上提高了过程的沉积速率.通过扫描电镜、能谱仪和X射线衍射仪对结构的分析,镀层铜纯净度较高,无氧化铜等夹杂,镀层细致平滑,发现SPS有促进(200)晶面择优取向的作用.

Effect of sodium 3,3'-dithiodipropane sulfonate in a dual-ligand electroless copper system

The process of electroless copper plating in an EDTA/THPED dual-ligand system using sodium 3,3'-dithiodipropane sulfonate ( SPS) as an additive was studied by the electrochemical method. The mixed potential of the system was measured as a func-tion of time, and results indicate that addition of SPS gradually shifts the mixed potential toward the negative direction without salta-tion. The dual-ligand electroless copper system was then tested by linear sweep voltammetry, and SPS is found to accelerate both ca-thodic and anodic polarization. The additive mainly influences the anodic polarization of the formaldehyde oxidation process and the rate of copper deposition is improved to a certain extent. The surface morphology and texture of the resulting plated copper were also analyzed by scanning electron microscope, energy dispersive spectrometer and X-ray diffraction, and a high-purity product without Cu2 O inclusions is confirmed. Moreover, the X-ray diffraction results of the electroless copper layers show that addition of SPS favors the formation of the preferred orientation on the (200) lattice plane.