Abstract Cobalt is a promising material for electronic interconnections in the post-Moore law period. However, the vertical cobalt pillar is not fully compatible with the current electroplating-involved manufacturing process due to hydrogen evolution at the cathode and poor throwing power of the products. In this article, electrodeposition with multiple organic additives was employed to realize the fabrication of cobalt pillars. Electrochemical measurements were used to investigate the depolarization of 3-mercapto-1-propane sulfonate sulfonic acid (MPS) and the polarization of the polyvinylpyrrolidone (PVP) during cobalt electrodeposition. Notably, the competitive adsorption between MPS and PVP was verified and discussed in cobalt electrodeposition. In order to understand the adsorption and functional groups of the additives, quantum chemical calculations were performed to simulate the distribution of electrostatic potential and molecular orbital energy of the additives. Accordingly, the thiol group of MPS and the amide group of PVP were speculated to be the molecular adsorption sites in cobalt electrodeposition. The mechanism including three stages was proposed for cobalt pillar electrodeposition in solution with MPS and PVP. The electrodeposition of practical cobalt pillars with a depth of 50 µm and diameters of 60, 80, and 100 µm was successfully achieved by electroplating experiments, thereby promoting the application of metal cobalt for electronic packaging.

中文翻译：

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3-巯基-1-丙烷磺酸和聚乙烯吡咯烷酮对电沉积钴柱生长的影响

摘要 在后摩尔定律时期，钴是一种很有前途的电子互连材料。然而，由于阴极析氢和产品的均镀能力差，垂直钴柱与当前涉及电镀的制造工艺并不完全兼容。在本文中，采用多种有机添加剂的电沉积来实现钴柱的制造。电化学测量用于研究钴电沉积过程中 3-巯基-1-丙烷磺酸 (MPS) 的去极化和聚乙烯吡咯烷酮 (PVP) 的极化。值得注意的是，MPS 和 PVP 之间的竞争吸附在钴电沉积中得到了验证和讨论。为了了解添加剂的吸附和官能团，进行量子化学计算以模拟添加剂的静电势和分子轨道能量的分布。因此，推测MPS的硫醇基和PVP的酰胺基是钴电沉积中的分子吸附位点。提出了在MPS和PVP溶液中钴柱电沉积的三个阶段的机理。通过电镀实验成功实现了深度50 µm、直径60、80、100 µm的实用钴柱的电沉积，从而推动了金属钴在电子封装中的应用。推测MPS的硫醇基和PVP的酰胺基是钴电沉积中的分子吸附位点。提出了在MPS和PVP溶液中钴柱电沉积的三个阶段的机理。通过电镀实验成功实现了深度50 µm、直径60、80、100 µm的实用钴柱的电沉积，从而推动了金属钴在电子封装中的应用。推测MPS的硫醇基和PVP的酰胺基是钴电沉积中的分子吸附位点。提出了在MPS和PVP溶液中钴柱电沉积的三个阶段的机理。通过电镀实验成功实现了深度50 µm、直径60、80、100 µm的实用钴柱的电沉积，从而推动了金属钴在电子封装中的应用。