面向第三代半导体封装互连的纳米铜膏及其低温无压烧结机理研究

The high temperature and high voltage characteristics of the third generation semiconductor power devices provide a higher requirement of electrical conductivity, heat dissipation, and interconnect reliability. The traditional solder and conductive adhesives cannot meet the packaging requirement of power devices due to their limitation of heat tolerance. Nano-metal interconnect materials possess the characteristics of low-temperature sintering and high-temperature service. Based on those characteristics, a new method for power device packaging interconnect using nano-copper pastes is proposed. In this project, the preparation of nano-copper materials with controllable size, oxidation resistance and assisted-sintering will be studied through using “microdissolution-ionization-reduction-dissolution” balance of slightly soluble copper sources and in-situ coating of imidazole derivatives. Meanwhile, the chemical assisted sintering process of different kinds of nano-copper pastes, also the sintering mechanism will be investigated from thermodynamics and dynamics with simulation and optimization. Key scientific problems such as the appropriate coating and effective removal mechanisms of organic shell on the surface of nanoparticles, besides the sintering diffusion mechanism of nano-copper pastes under different driving forces and their multi-parameter coupling match rules will be explored. The project will solve the aggregation and oxidation bottleneck of nano-copper material, establish the structure-activity relationship between nano-copper paste and chemical assisted sintering process as well as interconnect performance, finally realize the low-temperature and pressureless interconnect technology with nano-copper paste for the third generation of semiconductor power devices.

第三代半导体功率器件的高温高压工作特点对互连材料及工艺提出了较高的导电、散热及互连可靠性要求。传统焊料和导电胶因存在耐热局限，无法满足功率器件的封装互连及服役可靠性。新型纳米金属互连材料具备低温烧结，高温服役的特点，基于此本项目提出纳米铜膏实现功率器件封装互连的新方法，巧妙利用微溶铜源的“微溶解-电离-还原-再溶解”平衡和咪唑类衍生物的原位包覆，探索纳米铜形貌尺寸、抗氧化及助烧结的可控制备方法；研究不同种类纳米铜膏的化学辅助烧结工艺；并从热力学和动力学角度分析不同驱动力下的烧结机理，辅以烧结过程的模拟分析及工艺优化。项目拟通过研究颗粒表面有机物壳层的合理包覆与有效去除机制、不同驱动力下纳米铜膏烧结扩散机制及其多参数耦合匹配规律等关键问题，解决纳米铜材料易团聚和氧化带来的应用瓶颈，建立纳米铜膏与化学辅助烧结工艺及互连性能之间的构效关系，为第三代半导体大功率器件的低温无压封装互连提供可行方案。

本项目基于新型纳米金属互连材料低温烧结，高温服役的特点，提出了纳米铜膏实现功率器件封装互连的新方法，巧妙地利用了微溶铜源的“微溶解-电离-还原-再溶解”平衡和咪唑类衍生物的原位包覆，探索了纳米铜形貌尺寸、抗氧化及助烧结的可控制备方法；研究了不同种类纳米铜膏的化学辅助烧结工艺；并从热力学和动力学角度分析了不同驱动力下的烧结机理。项目通过研究颗粒表面有机物壳层的合理包覆与有效去除机制、不同驱动力下纳米铜膏烧结扩散机制，以及其多参数耦合匹配规律等关键问题，突破了纳米铜材料易团聚和氧化带来的应用瓶颈，建立了纳米铜膏与化学辅助烧结工艺及互连性能之间的构效关系，为第三代半导体大功率器件的低温无压封装互连提供了可行的解决方案。本项目已取得预期的研究成果，全面地完成了预期的考核指标。项目在国内外核心期刊共发表研究论文 14篇，其中，SCI 收录 5篇，EI 收录的包括会议文章共9篇，申请中国发明专利12件，授权中国发明专利10件。该项目执行过程中，共培养硕士研究生7名。项目负责人为大会秘书和材料分会主席参与主办了2020年第21届电子封装技术国际会议（21st International Conference on Electronics Packaging Technology，ICEPT 2020）一次。成员参加国际会议9人次，荣获最佳学生论文证书1次。