Polyvinylpyrrolidone (PVP) is studied in this paper as an inhibitor of cobalt electrodeposition. The suppression effect of PVP was analyzed through electrochemical methods, including cyclic voltammetry (CV) and galvanostatic measurements (GM) tests. It is indicated that PVP effectively suppresses the electrodeposition of cobalt and chloride ion accelerates this suppression. Further experiments verify that PVP inhibits the deposition of cobalt through the adsorption on the electrode surface. Quantum chemical calculations were employed to calculate the molecular orbitals of PVP and the electrostatic potential (ESP) energy of the involved molecules. The simulation results imply that the amide group acts as the main electrophilic attack region and facilitates nucleophilic reactions to bond with cobalt. High aspect ratio trench filling on silicon wafer was achieved with the addition of PVP, which confirms that PVP is an applicable inhibitor for the practical electrodeposition of cobalt filling. The mechanism of cobalt trench filling was proposed to explain the role of PVP in the electroplating filling. Besides, crystalline and morphological characterizations reveal that PVP is able to inhibit the specific crystal growth of cobalt, especially the growth of 220 crystal plane, affect the crystal morphology of cobalt and improve surface compactness.

本文研究了聚乙烯吡咯烷酮（PVP）作为钴电沉积抑制剂。通过电化学方法分析PVP的抑制作用，包括循环伏安法（CV）和恒电流测量（GM）测试。表明PVP有效地抑制了钴的电沉积，氯离子加速了这种抑制。进一步的实验证明PVP通过在电极表面的吸附作用抑制了钴的沉积。采用量子化学计算来计算PVP的分子轨道和所涉及分子的静电势（ESP）能量。模拟结果表明酰胺基团是主要的亲电子进攻区域，并促进亲核反应与钴键合。通过添加PVP，可以在硅晶片上实现高纵横比的沟槽填充，这证实了PVP是适用于实际的钴填充电沉积的抑制剂。提出了钴沟槽填充的机理以解释PVP在电镀填充中的作用。此外，晶体和形态特征表明，PVP能够抑制钴的特定晶体生长，尤其是220晶面的生长，影响钴的晶体形态并提高表面致密性。