功率LED芯片与热沉的焊料连接界面及服役效能研究

solder bonding is the most promising die-attach process in high power LED packaging, which has lower thermal resistance and higher device reliability in comparision with the traditional insulation paste or silver paste die-attach processes. In this project, the eutectic bonding technology is studied with using flux or in the vacuum furnace, the detailed preparation process is investigated, and the interfacial reliability was evaluated. In this study, the large-scale industrialization of eutectic bonding would be expected to come true in the LED packaging industry of China. Firstly, the interfacial microstructure and phase distribution are investigated with different bonding processes, such as changing flux, bonding temperature & time, bonding force and so on. Secondly, the formation, evolution and growth behavior of interfacial voids are studied in details, and effective ways would be developed to reduce the interfacial void rate. Thirdly, under complex multi-field coupling environment, the interfacial damage features and failure mechanism of eutectic bonding are studied and the interfacial reliability can be evaluated, which provides the theoretical basis for the interfacial reliability design. Effective ways would be developed to postpone the interfacial failure behavior, and also to solve the device reliability problems and prolong its service life. Finally, newer thermal interface materials and die-attach technologies would be brought forward. This study provides a theoretical basis for eutectic bonding process and interfacial design as well as the scientific basis for the LED device service reliability.

针对半导体照明产业界的散热瓶颈关键技术问题，以芯片与热沉的特殊焊料连接界面为研究对象，研究大面积薄层金属/薄层焊料/薄层金属的键合反应及服役效能。本项目拟采用焊剂共晶技术或真空共晶技术，研究制程参数对界面微观组织结构和性能的影响规律，分析多层界面耦合反应和缺陷形成机制，项目预期目标将揭示焊料薄层界面连接的界面键合机制和相应键合模型。研究界面在力、电和热单场等多场耦合作用下，多层连接界面的微观组织结构和空洞的演化规律，分析多层反应耦合作用下界面的损伤规律和失效行为，建立界面的失效机制模型，提出延缓界面失效的有效途径。项目的研究成果对于进一步揭示研究金属薄层与焊料薄层的界面反应方面具有重要意义，为电子封装技术中高密度、微小尺度材料连接的设计和生产提供科学依据。

焊料固晶技术是半导体照明产业界亟待攻克的散热瓶颈关键技术，本项目系统研究了制程参数对界面微观组织结构和性能之间的关系，.获得焊接界面在多场耦合作用下的界面微观组织结构和缺陷的演化规律，研究了界面在外场作用的原子扩散与化合物形成机制，揭示了界面的损伤失效规律。本项目深入研究了现有的几种共晶焊接技术的界面组织结构以及可靠性的基础数据，结合理论给出各种技术路线的优劣，为封装业界固晶技术应用与发展提供理论基础。创新采用免清洗flux界面焊接工艺，获得优异的固晶制程，并在产业界推广应用。提出有效的抗界面失效的新途径，在现有技术基础上进一步提高器件的使用可靠性。提出芯片与热沉异种材质界面连接的新技术路线，提出新的互联材料体系，推动功率LED器件封装技术的进一步发展。提出共晶焊技术和固晶技术可靠性的评判方法，并与企业联合制定相关的技术标准。.