欢迎访问《电化学(中英文)》期刊官方网站,今天是

电化学(中英文) ›› 2022, Vol. 28 ›› Issue (6): 2104431.  doi: 10.13208/j.electrochem.210443

所属专题: “电子电镀和腐蚀”专题文章

• 综述 • 上一篇    下一篇

芯片钴互连及其超填充电镀技术的研究进展

魏丽君1, 周紫晗1, 吴蕴雯1,*(), 李明1, 王溯2   

  1. 1.上海交通大学材料科学与工程学院,上海 200240
    2.上海新阳半导体材料股份有限公司,上海 201616
  • 收稿日期:2021-07-14 修回日期:2022-05-05 出版日期:2022-06-28 发布日期:2022-05-07
  • 通讯作者: 吴蕴雯 E-mail:tlwuyunwen@sjtu.edu.cn
  • 基金资助:
    国家自然科学基金项目(62004124);国家自然科学基金项目(61376107)

Research Progresses of Cobalt Interconnect and Superfilling by Electroplating in Chips

Li-Jun Wei1, Zi-Han Zhou1, Yun-Wen Wu1,*(), Ming Li1, Su Wang2   

  1. 1. College of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
    2. Shanghai Sinyang Semiconductor Materials Co., Ltd., Shanghai 201616, China
  • Received:2021-07-14 Revised:2022-05-05 Published:2022-06-28 Online:2022-05-07
  • Contact: Yun-Wen Wu E-mail:tlwuyunwen@sjtu.edu.cn

摘要:

芯片中的钴互连作为铜互连之后的下一代互连技术受到了业界的极大关注,且已经引入集成电路7 nm以下的制程。钴互连主要采用湿法的电化学沉积技术,但由于保密原因和研究条件的限制,其研究报道不多。本文基于现有专利、文献报道较系统地介绍了钴互连技术的优势及发展现状,并从溶液化学和电化学角度综述了钴互连电镀基本工艺、基础镀液组成与添加剂、超填充电镀机理,以及镀层退火控制与杂质影响等的研究现状,并对钴互连技术下一步研究进行了展望。

关键词: 钴, 电沉积, 超填充, 互连, 自下而上

Abstract:

Copper interconnect using dual damascene technology has always been the main means for metallization in the back end of line process. However, with the size effect becoming more and more obvious due to feature size reduction, copper interconnect can no longer meet the demand for high circuit speed in Post-Moore era. Following copper interconnection, cobalt interconnection in chips attracts much attention as an interconnect technology by the next generation, which has been introduced in 7 nm node of integrated circuit manufacturing and below. The electron mean free path of cobalt (~10 nm) is much shorter than copper’s (39 nm), thus exhibiting the potential to further shrink the critical dimension without increasing line resistance and RC delay especially for contacts or local interconnects in the first few stack layers. Also, cobalt is considered as a suitable barrier/liner material, which means implementing cobalt interconnects needs no such layers and gives more space for conductive metal. Besides, higher melting point of cobalt makes it more favorable with good electromigration resistance compared with copper interconnects. Cobalt interconnection mainly adopts the wet electrodeposition method and the quality of the electrodeposite matters a lot to the reliability of the metal interconnects. For the reason of confidentiality and the limitation of research conditions, there are few research reports about cobalt interconnection. Based on existing patents and literature reports, this paper systematically introduces the advantages and current developments of cobalt interconnection. To better understand the behavior of the metal ions during electroplating process, this paper reviews the basic technology, bath composition and additives used in the electrolyte for cobalt electroplating from the point of view of solution chemistry and electrochemistry. For superconformal electroplating, there are several superfilling mechanisms for bottom-up electrodeposition with different emphasis, this paper gives a brief summary about three mechanisms and makes a comparison. Furthermore, this paper introduces the annealing control of cobalt deposition and the influence of impurities, since the evolution of grains and migration of impurities determine the sheet resistance. Finally, further study of cobalt interconnection technology is prospected. Cobalt interconnect is expected to be a proper alternative to extend Moore’s Law and promises to play a part in next advanced technology node. More researches about cobalt interconnection are worthwhile to be carried out in the future.

Key words: cobalt, electrodeposition, superfilling, interconnect, bottom-up