Cu6Sn5单晶互连结构异质形核机制研究

Three-dimensional (3D) packaging structure is one of the key technologies for realizing the integration of multichip systems, and Cu6Sn5 single-crystal solder joints is considered to be the development direction of the next generation of 3D packaging structure. However, the different crystal orientations in solder joints limit the application of three dimensional integrated circuits (3D IC). Therefore, how to realize the directional nucleation in single-crystal solder joints becomes one urgent problem confronting us. This project focuses on the preparation of Cu6Sn5 single-crystal oriented structure under the condition of 3D high-density packaging and its structure-activity relationship. Firstly, the orientation relationship of FCC/HCP and HCP/HCP systems is predicted and regulated based on lattice matching theory and density functional theory; secondly, the limiting control frequency and lattice misfit control domain for Cu6Sn5 nucleation under the effect of orientation relationship are investigated through droplet solidification experiments and nucleation undercooling statistics, then the heterogeneous nucleation mechanisms of Cu6Sn5 single-crystal solder joints are clarified, and the control equation for Cu6Sn5 single-crystal orientation growth is obtained; lastly, in order to obtain the optimal structure design of solder joints in 3D IC, the failure modes during the serve of new interconnection structure are analyzed, and the relationship between its structure and performance are also discussed. The results lay a theoretical foundation for elucidating the heterogeneous nucleation theory of FCC/HCP and HCP/HCP systems, and provide new ideas for the design and development of new interconnection structures.

三维封装互连结构是实现多芯片间系统集成的关键技术之一，Cu6Sn5单晶结构被认为是下一代三维封装互连结构的发展方向，但是焊点的晶粒取向差异限制了三维集成电路（3D IC）的应用，如何实现焊点的单晶定向形核是急需解决的问题。本项目围绕三维高密度封装Cu6Sn5单晶定向结构制备与构效关系开展研究，首先基于晶格匹配理论和密度泛函理论预测并调控FCC/HCP和HCP/HCP体系的位向关系；其次基于熔滴凝固实验和形核过冷度统计分布，研究位向关系作用下的极限控制频数及晶格错配度控制域，阐明Cu6Sn5单晶互连结构焊点的异质形核机理，获得Cu6Sn5单晶定向生长的控制方程；最后分析全新互连结构服役过程中的失效模式，探讨Cu6Sn5单晶互连结构与性能的关系，实现3D IC焊点结构优化设计。研究结果为阐明FCC/HCP、HCP/HCP界面异质形核机理提供理论支撑，为设计和发展3D IC互连结构提供新的思路。

三维封装互连结构是实现多芯片间系统集成的关键技术之一，Cu6Sn5单晶结构被认为是下一代三维封装互连结构的发展方向，但是焊点的晶粒取向差异限制了三维集成电路（3D IC）的应用，如何实现焊点的单晶定向形核是急需解决的问题。本项目围绕三维高密度封装Cu6Sn5单晶定向结构制备与构效关系开展研究，首先基于晶格匹配理论和密度泛函理论预测并调控FCC/HCP和HCP/HCP体系的位向关系；其次基于熔滴凝固实验和形核过冷度统计分布，实现了单晶结构的制备；最后分析全新互连结构服役过程中的失效模式，探讨Cu6Sn5单晶互连结构与性能的关系，实现3D IC焊点结构优化设计。研究结果为阐明FCC/HCP、HCP/HCP界面异质形核机理提供理论支撑，为设计和发展3D IC互连结构提供新的思路。共发表论文16篇，其中在Journal of Materials Research and Technology, Materials Letters, applied sciences-base, Welding in the World, Applied Physics A-Materials Science & Processing, Materials Today Communication, Soldering & Surface Mount Technology, Solid State Sciences等期刊上发表SCI论文12篇，在IIW国际会议上发表论文2篇，申请发明专利3项，已授权发明专利1项，在《机械工程学报》和《中国有色金属学报》国内知名期刊发表EI论文2篇；培养研究生毕业4名。