EPE系列镀铜抑制剂的填孔性能与作用机理研究

发布时间：2018-01-20 14:33

本文关键词： 填孔镀铜超填孔抑制剂填孔率 RRDE　出处：《哈尔滨工业大学》2013年博士论文　论文类型：学位论文

【摘要】：盲孔金属化是实现印制电路板(Printed Circuit Board, PCB)层与层之间电器互联的有效手段，更是高密度互联(High Density Interconnection, HDI)板发展的关键技术之一。为保证电路连接的可靠性，盲孔需要被电镀铜层完全填充，在此工艺过程中电镀时间、面铜厚度以及盲孔的填孔率是衡量酸铜镀液性能的重要指标。目前，国内市场上的电镀铜填盲孔镀液几乎被国外品牌所垄断，这对我国PCB产业的发展极为不利。因此，开发一种具有自主知识产权的高效盲孔镀铜液具有十分重要的现实意义。一般而言，在不含添加剂的酸铜镀液中电镀铜填盲孔时，由于孔底部的电流密度相对较小，沉铜速度相对缓慢，因此无法实现对盲孔的填充。只有当镀液中含有氯离子、加速剂、抑制剂和整平剂时，通过添加剂之间的相互作用，改变盲孔底部与面板表面电流密度的分布差异，才能最终实现对盲孔的完美填充，也称作超填孔(Superfilling)。本研究以EPE系列(由环氧乙烷EO与环氧丙烷PO组成的三嵌段聚合物)抑制剂的筛选为切入点，通过研究抑制剂的抑制强度与盲孔填孔率的关系，最终筛选出综合性最佳的抑制剂EPE2900，其EO含量为40%，分子量为2900。对比实验结果表明，作为电镀铜填盲孔的抑制剂，EPE2900比常规抑制剂PEG6000更优秀。因此，本文选择EPE2900为抑制剂，以填盲孔的效果为衡量标准对电镀铜填盲孔的工艺配方进行了优化，优化结果：220g/L CuSO4·5H2O、54g/L H2SO4、60mg/L Cl-、6mg/L SPS、200mg/L EPE2900和4mg/L JGB。采用此优化配方，控制电流密度2A/dm2，电镀时间60min，镀液温度25℃，填孔(孔径125μm，孔深100μm)实验结束后，面铜厚度约为16μm，填孔率高达95%。在优化的电镀铜填盲孔配方中，使用旋转圆盘电极，采用循环伏安法和计时电位法，系统地研究了各种添加剂的独立作用以及相互作用。研究结果表明，EPE2900与Cl-之间存在明显的正协同作用，换句话说，Cl-的存在可以大幅度提高EPE2900对铜离子沉积的抑制作用。此外，对于每一个固定浓度的EPE2900，都存在一个最佳的Cl-浓度使其对铜沉积的抑制作用达到最大值。抑制剂EPE2900在阴极表面的吸附是一个快速过程，而SPS在阴极表面的吸附则是缓慢进行的，二者在电极表面发生竞争吸附，强对流有利于EPE2900的吸附。在镀液中引入整平剂JGB，可以协同提高EPE2900的抑制作用。循环伏安实验结果表明，与其它添加剂相比，EPE2900与Cl-之间的协同作用最为显著，其对铜离子沉积的稳定电位具有决定性的影响。利用Material Studio(MS)模拟软件和Gaussian计算软件分别对EPE2900分子在水溶液中的空间构型以及分子中氧原子的电负性进行了模拟计算。在分析不同条件下的填孔实验结果的基础上，结合EPE2900与其他添加剂之间的相互作用，提出了EPE2900在阴极表面吸附的简单模型。然后利用线性扫描、计时电位和电化学阻抗等电化学测试方法对提出的模型进行了证明。为进一步明确EPE2900在电极表面的吸附机制，本文采用循环伏安溶出法(CVS)，，对铜溶解峰的积分面积值Q受EPE2900和Cl-浓度的影响进行了系统研究。结果表明，当镀液中含有固定浓度的EPE2900时，随着Cl-浓度在一定范围内增加，Q值逐渐减小，这说明Cl-浓度的增加可以提高EPE2900的抑制作用。重要的是，我们发现当Cl-浓度在0~10mg/L之间增大时，Q值下降得很快；然而当Cl-浓度大于10mg/L时，随着Cl-浓度的增加，Q值的下降速度明显变缓。据此实验现象，采用分段线性拟合的方法，计算出曲线拐点的横坐标，此横坐标对应的Cl-浓度，即是EPE2900在阴极表面达到临界吸附时所需的最低Cl-浓度。用相同的研究方法计算出当镀液中含有固定浓度的Cl-时，曲线拐点的横坐标，即达到临界吸附时所需的EPE2900的最低浓度。多组平行实验的结果都证明，EPE2900在电极表面达到临界吸附时，镀液中EPE2900和Cl-的最低浓度分别为11.46mg/L和4.85mg/L。根据Q值随EPE2900和Cl-浓度增加而下降的变化趋势，提出了EPE2900在临界吸附状态时的吸附模型，同时详细地描述了随着EPE2900和Cl-浓度的增加吸附模型的改变情况。特别的，本文引入旋转环盘电极(RRDE)测试技术证明了EPE2900可以和Cu+相互作用，佐证了EPE2900吸附模型的合理性。
[Abstract]:The blind hole metallization is a printed circuit board (Printed Circuit, Board, PCB) effective means between layer and layer electrical interconnection, is of high density interconnection (High Density Interconnection, HDI) is one of the key technologies in development. In order to ensure the reliability of circuit connection, blind hole copper plating layer needs to be completely filled, the plating time in this process in the process of filling rate and thickness on the surface of the blind hole is an important index to measure the acid copper plating solution performance. At present, the domestic market of the copper plating bath filled hole is almost monopolized by foreign brands, the development of China's PCB industry is extremely unfavorable. So it has very important practical significance to develop a blind, with independent intellectual property rights of the copper plating solution.
In general, in acid copper containing no additives in the plating solution for electroplating copper with blind hole, because the current density at the bottom of the hole is relatively small, the copper deposition speed is relatively slow, it can not be filled to the blind hole. Only when the plating solution containing chloride ions, accelerating agent, inhibitor and leveling agent, through the interaction of additive the difference of distribution of current density at the bottom of the blind hole with the surface of the panel, to achieve the perfect blind hole filling and ultimately to, also known as super pore filling (Superfilling).
This research is based on the EPE series (composed of ethylene oxide and propylene oxide EO PO three block copolymer) inhibitor screening as the starting point, the relationship between strength and research of inhibitors by inhibiting the blind hole filling rate, finally screened the best synthesis inhibitor EPE2900, the content of EO is 40%, the molecular weight of 2900. experiments the results show that the inhibitor for copper electroplating filling blind, EPE2900 PEG6000 is more excellent than conventional inhibitors. Therefore, this paper chooses EPE2900 as the inhibitor, formulation standard for copper electroplating of the blind hole to fill the hole filling effect is optimized, the optimization results: 220g/L CuSO4, 5H2O 54g/L, H2SO4,60mg/L Cl-, 6mg/L SPS, 200mg/L EPE2900 4mg/L and JGB. using the optimized formulation, control the current density of 2A/dm2, plating time 60min, bath temperature of 25 DEG C, filling holes (diameter 125 m, hole depth 100 m) after the end of the experiment, the surface copper thickness is about 16 m, fill in The hole rate is up to 95%.
Fill in the blind hole copper plating formula optimization, using the rotating disk electrode by cyclic voltammetry and chronopotentiometry, systematically studied the independent effects of various additives and interaction. The results show that there are obvious synergistic effect between EPE2900 and Cl-, in other words, the presence of Cl- can greatly improve the inhibition effect of EPE2900 on copper deposition. In addition, for each fixed concentration of EPE2900, there is an optimal Cl- concentration to its inhibitory effect on the deposition of copper reaches the maximum value. Inhibitor EPE2900 on the cathode surface adsorption is a fast process, and the adsorption of SPS on the cathode surface is slow the two has a competition adsorption on the electrode surface, strong convection favors the adsorption of EPE2900. The introduction of JGB leveling agent in the bath, can enhance the inhibitory effect of EPE2900. The experimental results show that cyclic voltammetry, Compared with other additives, the synergistic effect between EPE2900 and Cl- is the most significant, and it has a decisive influence on the stable potential of copper ion deposition.
The use of Material Studio (MS) simulation software and Gaussian software respectively on the spatial structure of EPE2900 molecule in aqueous solution and molecular oxygen in the electronegativity of atoms was simulated under different conditions. In the analysis of hole filling on the basis of experimental results, combined with the interaction between EPE2900 and he put forward EPE2900 additive. In a simple model of the cathode surface adsorption. Then linear scanning, chronoamperometry and electrochemical impedance and other electrochemical method to demonstrate the proposed model.
In order to further clarify the mechanism of EPE2900 adsorption on the electrode surface, the dissolution method by cyclic voltammetry (CVS), the integral area of copper dissolution peak value of Q is affected by EPE2900 and Cl- concentration were studied. The results show that, when the fixed concentration in the bath containing EPE2900, with the increase of Cl- concentration in a certain within the range of Q value decreased gradually, indicating that the increase of Cl- concentration can enhance the inhibitory effect of EPE2900. Importantly, we found that when the concentration of Cl- in 0~10mg/L increased, Q decreased quickly; however, when the concentration of Cl- is higher than 10mg/L, with the increase of Cl- concentration, Q value of the rate of decline significantly slow. According to the experimental phenomena, by using the method of piecewise linear fitting, calculate the horizontal coordinate curve inflection point, the horizontal axis corresponds to the concentration of Cl-, which is the lowest concentration of Cl- EPE2900 required to reach the critical adsorption on the surface of the cathode. The use of the same. Method to calculate when the fixed concentration in the bath containing Cl-, the abscissa curve inflection point, namely the minimum concentration required to reach the critical adsorption of EPE2900. Multi group parallel experimental results show that the EPE2900 reaches the critical adsorption on the electrode surface, the lowest concentration of EPE2900 and Cl- in the plating solution were changing trend 11.46mg/L and 4.85mg/L. decreased according to the value of Q with EPE2900 and Cl- concentration increased, adsorption model was proposed in EPE2900 critical adsorption state, and a detailed description of the EPE2900 and Cl- concentration increased with the change of adsorption model. Especially, this paper introduces a rotating ring disk electrode (RRDE) test proved that the EPE2900 can the interaction between Cu+ and EPE2900, proved the rationality of adsorption model.

【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】：2013
【分类号】：TQ153.1

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