由于服役温度高、材料构成复杂，功率模块封装结构各互连焊料层中温度梯度较大，无铅焊料层的可靠性面临来自热迁移的严重威胁。热迁移条件下，焊料层中不同金属原子的迁移触发条件及其对互连界面产生的拉压应力等基础科学问题亟待深入理解。. 基于此，本研究从热迁移条件下界面金属间化合物的挤出行为这一细微现象着手，结合实验和分子动力学模拟深入研究无铅焊料金属原子热迁移行为的触发条件和迁移规律，并系统分析不同热加载条件下金属原子迁移对互连界面产生的拉压应力及其对界面可靠性的影响。本项目通过对这些基础科学问题的研究能够获得可靠、完整的数据，对功率半导体模块封装中的结构设计、材料选择、工艺实施等提供参考。

The reliability of solder layers in power electronics packaging structures is significantly threatened from thermo-migration, since the complicated structure of these modules, the relatively high service temperature and thermal gradient. .At present，the triggering conditions of thermo-migration of different metal atoms are unknown, while the interfacial intension/compress stresses and their influence caused by atomic migration are also need to be understood. . In this study，the triggering conditions of theromo-migration of different solder atoms will be studied using experiments and first principle theory. Further, the interfacial intension/compress stresses and their influence on reliability of interfaces will also be systematically discussed. This research can significantly enrich the current theories on the structural design, choice of materials and processing parameters of power modules.