Lu Tsan-Feng, Cheng Yuan-Fu, Wang Pei-Wen, Yen Yu-Ting, Wu YewChung Sermon
Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan.
Materials (Basel). 2024 Jul 13;17(14):3467. doi: 10.3390/ma17143467.
Cu-Cu joints have been adopted for ultra-high-density packaging for high-end devices. However, the atomic diffusion rate is notably low at the preferred processing temperature, resulting in clear and distinct weak bonding interfaces, which, in turn, lead to reliability issues. In this study, a new method for eliminating the bonding interfaces using two types of Cu films in Cu-Cu bonding is proposed. The difference in grain size was utilized as the primary driving force for the migration of bonding interfaces/interfacial grain boundaries. Additionally, the columnar nanotwinned Cu structure acted as a secondary driving force, making the migration more significant. When bonded at 300 °C, the grains from one side grew and extended to the bottom, eliminating the bonding interfaces. A mechanism for the evolution of the Cu bonding interfaces/interfacial grain boundaries is proposed.
铜-铜接头已被用于高端设备的超高密度封装。然而，在优选的加工温度下，原子扩散速率显著较低，导致结合界面清晰且明显薄弱，进而引发可靠性问题。在本研究中，提出了一种在铜-铜键合中使用两种类型的铜膜来消除键合界面的新方法。利用晶粒尺寸的差异作为键合界面/界面晶界迁移的主要驱动力。此外，柱状纳米孪晶铜结构作为次要驱动力，使迁移更加显著。当在300°C下键合时，一侧的晶粒生长并延伸到底部，消除了键合界面。提出了铜键合界面/界面晶界演变的机制。
