基于有限元方法分析加速剂SPS对铜柱凸点互连均匀性的影响  

The influence of accelerator SPS on the bump surface of copper pillar interconnects based on finiteelement simulation methods

作　　者：彭雪嵩 江杰 李铭杰 王福学 罗秀彬 杨培霞 张锦秋 李亚强 李若鹏 安茂忠 Peng Xuesong;Jiang Jie;Li Mingjie;Wang Fuxue;Luo Xiubin;Yang Peixia;Zhang Jinqiu;Li Yaqiang;Li Ruopeng;An Maozhong(School of Chemistry and Chemical Engineering,Harbin Institute of Technology,Harbin 150001,China;College of Chemistry,Fuzhou University,Fuzhou 350116,China;Institute of Molecular Engineering Plus,Fuzhou University,Fuzhou 350116)

机构地区：[1]哈尔滨工业大学化工与化学学院,黑龙江哈尔滨150001 [2]福州大学化学学院,福建福州350116 [3]福州大学分子工程+研究院,福建福州350116

出　　处：《电镀与精饰》2025年第3期10-17,共8页Plating & Finishing

基　　金：国家重点研发项目(2021YFB3400800);国家自然科学基金(22402041)。

摘　　要：铜柱互连因具有细间距、高导电性、高可靠性的优点,成为传统焊点的替代品。然而,铜柱生长过程容易形成光滑度很差的凹凸表面,严重影响铜柱的可靠性。本文采用有限元方法研究了加速剂聚二硫二丙烷磺酸钠(SPS)对铜柱生长的影响。基于电化学测试、分子动力学模拟以及有限元拟合方法,建立了基于物质传质、添加剂吸附、电极表面电化学还原以及铜柱生长的有限元仿真模型。在无添加剂的条件下,铜柱的生长可分为均匀生长阶段和凹形生长阶段,最终会形成凹形的铜柱顶面。引入SPS后,在生长过程中,SPS会在底角处积累,铜柱的生长呈现“V”形生长的特点。随着“V”形生长的进行,由于铜柱的轮廊拓扑变化,会在中间部位形成新的底角,SPS在中间区域的积累会加速铜的沉积。因而通过调控SPS的浓度,可以调控铜柱的生长过程,得到高均匀性的铜柱。The Copper pillar is regarded as a promising alternative compared with traditional solder bump due to its fine pitch,high electricity and high reliability.However,bad surface smoothness is easily formed during the electrodeposition of copper pillar,which had a bad influence on the reliability.In this work,finite element simulation was applied to investigate the influence of Bis-(Sodium Sulfopropyl)-Disulfide(SPS)on the surface morphology.The copper pillar growth model takes mass transfer process,adsorption and desorption of additive,electrochemical reduction on cathode surface and growth process into account based on electrochemical methods,molecular dynamics simulation and finite element fitting methods.The copper pillar growth process can be divided into two stages,uniform growth stage and concave growth stage without the influence of additives.After the introduction of SPS,the accumulation of SPS at the bottom corners results in a "V"-shape growth process.As the "V"-shape growth proceeds,the topological changes of copper pillar contour lead to the accumulation of newly-formed corner in the center area and the copper deposition is improved.Therefore,it is significant to regulate SPS concentration to control the copper pillar growth process to obtain copper pillar with high uniformity.

关 键 词：有限元模拟 分子动力学模拟 铜柱生长 均匀性 

分 类 号：TQ153.1[化学工程—电化学工业]