高热流密度下低银SAC微焊点加速热疲劳研究

With the rapid development of integrated circuit (IC) technology, the volume of electronic components was getting smaller and smaller, and the power of the chip was more and more big, which resulted in an increasing of the heat flux density in package body. The package body had enough time to resist the change of external temperature by warp or even deformation in the process of conventional thermal cycling and thermal shock, and the stress of solder joint was partly released,which could not be reflected the thermal effect of high power devices in the process of turn on or off and rapid pulse process. Besides, a single cycle test time of conventional thermal cycling and shock was long, which would take too long and require too many human resources. Therefore, BGA solder joints of low-silver SAC lead-free solder were prepared firstly in the project, and then the service environment of solder joint with large cycle (more than 1000 cycles),high frequency((10 ~ 30s/scycle) and rapid change in temperature (above 10 ℃/s) were designed, the microstructure evolution and the heat fatigue failure mechanism of solder joints for the extreme conditions finally were researched.The migration rule of solid-state atomic and the failure mode of solder joint were explored, a new accelerated thermal fatigue test method and the mathematical model of failure were also established. The project can expand the influence and competitiveness of China's electronics industry, guarantee the safety of the electronic information industry and reduce energy consumption.

随着大规模集成电路的迅速发展，电子元器件的体积越来越小，芯片所承载的功率却越来越大，导致封装体内的热流密度日益提高。常规的热循环和热冲击过程中，封装体有足够的时间产生翘曲甚至是变形来抵抗外部温度变化，应力得到了部分释放，不能真实反映某些大功率器件在往复通断和快速脉冲过程中的热影响。此外，常规热循环和热冲击单个周期实验时间长，致使电子产品热可靠性检测消耗大量的人力物力。因此，本项目提出了采用低银SAC无铅钎料制备BGA微连接焊点，模拟大周期（1000周期以上）、高频率(10~30s/周期)、快速温度变化(10℃/s以上)的焊点服役环境，研究焊点在极端条件下的组织演变及热疲劳失效，探索焊点中固态原子迁移规律及焊点失效模式，建立焊点加速热疲劳的试验新方法。项目的实施，对于扩大我国在世界电子行业的影响力、竞争力和话语权，保障电子信息产业的安全及节能减排都具有极其重要的实际意义

随着大规模集成电路的迅速发展，电子元器件的体积越来越小，芯片所承载的功率却越来越大，导致封装体内的热流密度日益提高。常规的热循环和热冲击不能真实反映某些大功率器件在往复通断和快速脉冲过程中的热影响。本项目设计和研制加速热疲劳实验设备，采用SAC无铅钎料制备BGA微连接焊点，模拟焊点在大周期（1000周期以上）、高频率(20~30s/周期)、快速温度变化(10℃/s以上)的服役环境，研究了不同拘束力下（无拘束、单面拘束、双面拘束）、不同银含量（0%~3.5%）和不同直径的锡球、凸点、三明治焊点表、内部裂纹、组织演变，探索固态原子迁移规律及焊点失效机理，为无铅焊点尺寸微小化及服役环境极端化可靠性提供借鉴。项目的实施，对于扩大我国在世界电子行业的影响力、竞争力和话语权，保障电子信息产业的安全及节能减排都具有极其重要的实际意义。