甲磺酸电镀锡添加剂设计优选及作用研究

发布时间：2018-06-02 02:38

本文选题：甲磺酸 + 添加剂　；参考：《哈尔滨工业大学》2016年博士论文

【摘要】：近年来,随着人们对环境问题的关注和重视,甲磺酸因具有无毒及完全生物降解特点,逐渐成为镀锡应用新方向。目前,国内市场上的甲磺酸电镀锡用添加剂几乎被国外品牌垄断,这对国内电镀锡产业发展极为不利。因此开发具有自主知识产权的镀锡添加剂具有十分重要的现实意义。在本文中,利用量子化学计算和分子动力学模拟(MD),结合电化学测量,镀液性能测试和扫描电子显微镜等手段对甲磺酸镀液体系稳定性、添加剂优选、镀液性能优化、锡初始成核过程以及添加剂在阴极表面作用进行了研究。甲磺酸分子的电子特性和轨道信息表明磺酸基(-SO_3)是分子中亲电和亲核的活性位置,甲磺酸根(MSA-)的EHOMO能量值为-1.53 e V,ΔEHOMO-LUMO为6.837 e V,根据前线轨道理论,说明MSA-与金属表面吸附作用强于硫酸,其静电势分布显示MSA-倾向于在金属表面垂直吸附;结构优化结果证实甲磺酸锡体系中有Sn[MSA]+、Sn[MSA]3-和Sn[MSA]2~(2+)三种络合构型存在;循环伏安曲线(CV)表明甲磺酸基础镀液的阴极极化度大于硫酸体系,但这种弱阴极极化不能抑制锡枝晶的生长。选择对苯二酚作为甲磺酸镀锡液稳定剂,其酚醌结构转换实现电化学可逆循环,能够长期稳定镀液。通过铁离子对锡离子氧化水解的影响研究发现,Sn~(2+)的氧化水解遵循先氧化生成Sn~(4+)再水解形成沉淀的路径,Fe~(3+)不能与Sn~(2+)共存,直接将Sn~(2+)氧化成Sn~(4+),Fe~(2+)在5~15 g/L时,具有减缓Sn~(2+)氧化水解速度的作用,Fe~(2+)为10 g/L时,其减缓作用最强。为了从甲磺酸体系中获得有用镀层,本文通过添加剂的界面作用实现对镀锡阴极过程的控制,优选出不同抑制能力的添加剂控制Sn~(2+)的放电过程,获得亚光到全光亮的锡镀层外观。首先,基于亚光镀锡添加剂一般特征,根据分子物化特性和前线轨道理轮,从聚醚中设计优选出环氧乙烷环氧丙烷嵌段聚合物EPE4600,其分子量为4600,EO占40 wt%,作为甲磺酸镀锡阴极抑制剂,获得了亚光锡镀层。静态下Hull cell测试显示EPE4600浓度为0.8~1.6 g/L,[Sn~(2+)]为15 g/L时,EPE4600允许镀液最大电流密度为8.0 A/dm2(市售高速镀锡TPG7添加剂为3.0 A/dm2),结合EPE4600浊点为79℃,综合表明该镀液允许在宽电流密度和宽温度区间工作,符合高速电镀要求。通过旋转圆盘电极(Pt-RDE)在不同调制动力学条件下EPE4600在镀液中的伏安特性和计时电位曲线说明EPE4600在阴极表面吸附并生成一层阻挡膜,该膜层阻碍Sn~(2+)扩散传递,是提高镀液阴极极化度和抑制锡枝晶生长的本质,据此建立了EPE4600吸附阻机理挡模型。密度泛函理论(DFT)计算和MD共同佐证了EPE4600在甲磺酸体系中,EPE4600分子中PO嵌段部分与界面具有较强的吸附活性,与MSA-存在协同吸附作用。通过暂态电流曲线研究EPE4600在甲磺酸-硫酸混合体系中锡成核行为,发现甲磺酸体系中,锡的成核符合扩散控制下的三维连续成核模型,硫酸的引入,锡初始沉核模型倾向于瞬时成核转变。计算了的锡初始成核活性位点(N0)和生长速率(A),临界吉布斯成核自由能(ΔGcrit)和临界成核尺寸(Ncrit),结果显示甲磺酸体系中锡在电极表面活性位点是硫酸及其混酸体系的5~10倍,Ncrit为0~1.5说明电极表面活性位点上有部分基底原子参与成核,锡与基底原子有很强的结合能。锡的初始沉积形貌印证了电化学的成核特征。将EPE4600用于高速电镀制备0.7 g/m2低锡量镀层,结果显示镀层均匀性和致密性优良,可用于低锡量高速钢板电镀锡,节约锡资源。为了实现对甲磺酸体系镀锡阴极过程的进一步抑制,获得光亮外观镀层。优选出糠叉丙酮、苄叉丙酮和戊二醛为光亮剂,NP-10和NS-665为复合载体的光亮剂组合。开发了光亮锡HIT-2添加剂配方,实现了无甲醛光亮镀锡工艺,静态下镀液最大光亮电流密度范围为0~5.1 A/dm2,得到(112)晶面强织构的光亮锡镀层,可用于卷对卷式的连续电镀工艺。基于HIT-2添加剂各组分在锡电沉积过程中的电化学行为,发现苄叉丙酮和糠叉丙酮共同吸附抑制了Sn~(2+)的放电过程,戊二醛和丙烯酸削弱了苄叉丙酮和糠叉丙酮的吸附作用,这种反作用实现了光亮锡的电沉积。MD发现了苄叉丙酮和糠叉丙酮分子倾向于平铺吸附,提出了添加剂分子间的界面吸附构型。甲磺酸亚光和光亮镀锡添加剂在通孔电镀中,实现了通孔内外选择性镀锡,揭示了可作为微凸点电镀工艺,用于高集成度芯片互联封装。
[Abstract]:In recent years, with the attention and attention to environmental problems, methanesulfonic acid has gradually become a new direction for the application of tin plating because of its non-toxic and complete biodegradation characteristics. At present, the additives for electroless tin plating on the domestic market are almost monopolized by foreign brands, which are extremely unfavorable for the development of electroplating tin industry in China. Therefore, the development has independent knowledge. The tin plating additives for property rights are of great practical significance. In this paper, the stability of the sulfonic acid bath system, the optimization of additives, the optimization of the performance of the plating solution, the initial nucleation process of tin, and the addition of the chemical measurement and molecular dynamics simulation (MD), the electrochemical measurement, the electroplating performance test and the scanning electron microscope are used in this paper. The effect of addition agent on the surface of the cathode was studied. The electronic properties and orbital information of mesylsulfonic acid molecules indicate that sulfonic acid group (-SO_3) is the active position of electrophilic and nucleophilic in the molecule. The EHOMO energy of MSA- is -1.53 e V and delta EHOMO-LUMO is 6.837 e V. According to the front line theory, the adsorption of MSA- and metal surface is stronger than sulfur. The static potential distribution of acid shows that MSA- tends to adsorb vertically on the metal surface, and the structural optimization results confirm that there are three complex configurations of Sn[MSA]+, Sn[MSA]3- and Sn[MSA]2~ (2+) in tin mesylate system, and cyclic voltammetry curve (CV) indicates that the cathodic polarity of the base plating solution is larger than the sulphuric acid system, but the weak cathode polarization can not be suppressed. The growth of tin dendrites. The conversion of phenols as a tin plating bath stabilizer, the conversion of phenol quinone structure to the electrochemical reversible cycle, can stabilize the bath for a long time. Through the effect of iron ion on the oxidation hydrolysis of tin ions, it was found that the oxidation hydrolysis of Sn~ (2+) followed the first oxidation of Sn~ (4+) to form the precipitation path, Fe~ (3+) did not. Coexistence with Sn~ (2+) can directly oxidize Sn~ (2+) into Sn~ (4+) and Fe~ (2+) in 5~15 g/L, which has the effect of slowing down the oxidation hydrolysis of Sn~ (2+). When it is 10, it has the strongest slowing down effect. In order to obtain a useful coating from the sulfonic acid system, this article passes the interface action of the additive to realize the control of the process of tin plating cathodic process. The suppressing additive controls the discharge process of Sn~ (2+) and obtains the appearance of the light to all bright tin coating. First, based on the general characteristics of the tin plating additive, the epoxy propane epoxy propane block polymer EPE4600 is designed and optimized from the molecular physicochemical properties and the front orbital wheel. The molecular weight of the polymer is 4600, and the EO is 40 wt%. The tin coating was obtained for the tin plating tin cathode inhibitor. The static Hull cell test showed that the maximum current density of EPE4600 was 8 A/dm2 (3 A/dm2) when the concentration of EPE4600 was 0.8~1.6 g/L and [Sn~ (2+)], and the nodal cloud point was 79 C. The flow density and wide temperature range work in accordance with the high speed electroplating requirements. The volt ampere characteristic and the timing potential curve of the EPE4600 in the bath under the different modulation kinetics conditions show that EPE4600 adsorbs on the surface of the cathode and generates a layer of barrier film on the surface of the cathode, which hinders the diffusion transfer of Sn~ (2+) and increases the cathode pole of the plating bath. The nature of inhibition and inhibition of the growth of tin dendrite was established. The EPE4600 adsorption resistance mechanism model was established. The density functional theory (DFT) calculation and MD co supported that EPE4600 was in the mesylate system. The PO segment in EPE4600 molecules had strong adsorption activity with the interface, and there was a synergistic adsorption with MSA-. The transient current curve was used to study EPE46. 00 in the methanesulfonic acid sulphuric acid mixing system, the nucleation of tin in a sulfonic acid system shows that the nucleation of tin conforms to the three-dimensional continuous nucleation model under the control of diffusion. The introduction of sulphuric acid, the initial nucleation model of tin is inclined to the transient nucleation transformation. The initial nucleation active site (N0) and growth rate (A) of tin are calculated, and the critical Gibbs nucleation free energy (delta G) Crit) and critical nucleation size (Ncrit) show that the surface active site of tin in the sulfonic acid system is 5~10 times of sulfuric acid and its mixed acid system. Ncrit is 0~1.5 indicating that some basal atoms are involved in the nucleation on the surface active site of the electrode, and the tin has strong binding energy to the substrate. The initial deposition morphology of tin confirms the electrochemistry. EPE4600 is used to prepare 0.7 g/m2 low tin coating for high speed electroplating. The results show that the coating has good uniformity and compactness. It can be used for electroless tin plating of high speed steel plate with low tin content and save tin resources. In order to further restrain the process of tin plating cathodic plating on methanesulfonic acid system, the bright appearance coating is obtained. The optimization of furfurone acetone, benzyl acetone is obtained. With glutaraldehyde as a brightener, NP-10 and NS-665 as the combination of brighteners, a brightening tin HIT-2 additive formula was developed to achieve a formaldehyde free tin plating process. The maximum bright current density range in the static bath was 0~5.1 A/dm2, and the bright tin coating with (112) strong textured surface was obtained, which could be used for roll to roll continuous electroplating. Based on the electrochemical behavior of HIT-2 additives in the electrodeposition of tin, it was found that the CO adsorption of benzyl acetone and furfurone acetone inhibited the discharge process of Sn~ (2+), and glutaraldehyde and acrylic acid weakened the adsorption of benzyl acetone and furfurone acetone. This reaction realized the electrodeposition of bright tin.MD and found benzyl acetone and bran. An intermolecular interface adsorption configuration between the molecules of the proproacetone molecule is put forward. The sub light and bright tin plating additives of mesylate have been used in the through hole electroplating to realize the selective tin plating inside and outside the hole. It reveals that the electroplating process can be used as a micro convex point plating process for high integration chip interconnected package.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ153.13

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