功率互连全IMC焊点的研究进展

Progress advances in full IMC solder joints for power electronic

全金属间化合物焊点具有“低温制备,高温服役”技术优势,成为最可能替代用于高温环境的高铅焊料、Au基焊料等连接材料。本文概述了低温烧结、固液互扩散键合技术、瞬态液相连接等方法制备全金属间化合物(IMC)焊点的特点,综述了Cu/Sn、Cu/In、Sn/Ag、Sn/Ni等体系制备全IMC焊点的研究进展,指出键合时间太长、相变会产生孔洞等缺陷是制约IMC生产应用的主要问题,认为应结合Cu-Cu接头的结构特点和材料性能,在焊料体系方面开发更多基于Sn基、Cu基、Sn-Cu基二元或三元焊料体系,更多地关注焊料的状态、尺寸、制备方法;在制备方法方面,把母材和焊料构造为一个冷热微循环,对焊料进行如飞秒激光、局部激光、感应加热等瞬态、局部高功率加热,同时对母材进行高功率制冷,适当辅助振动和压力能增加碰撞扩散几率和缩短扩散距离,就能快速获得单一高可靠性全IMC焊点。

Full intermetallic compound solder joints have become the most alternative to high lead solder,Au based solder and other connecting materials utilized in high temperature environment since they can be prepared at low temperature and serve at high temperature.The characteristics of full IMC prepared by low temperature sintering,solid-liquid interdiffusion bonding and transient liquid phase method were summarized.Furthermore,the research progress of full IMC soldered by Cu/Sn,Cu/In,Sn/Ag and Sn/Ni systems was reviewed.It is reported that the main problems restricting the production and application of IMC are too long bonding time and defects such as voids caused by phase transformation.Notably,the structural characteristics and material properties of Cu-Cu joints should be considered comprehensively.In terms of solder system,more binary solder systems based on Sn,Cu and Sn-Cu or ternary solder systems were essential to be developed.Afterwards,the state,size as well as preparation methods of solders should be attached great importance.Besides,in terms of preparation method,the base metal and solder were constructed as a cold and hot microcirculation.On the one hand,the solder was subjected to transient and local high-power heating such as femtosecond laser,local laser or induction heating.On the other hand,the base metal was subjected to high-power refrigeration.Afterwards,appropriate auxiliary vibration and pressure can boost the collision diffusion probability and shorten the diffusion distance,so as to quickly obtain a single full IMC solder joint with high reliability.