摘要
针对微小卫星对遥感数据处理和传输载荷的小型化、智能化、功能综合、组网协同等全新需求,需要解决单板上flash、ddr等大量存储器类无铅BGA封装器件的双面贴装技术问题。采用Surface Evolver软件对SS面BGA焊点形态进行仿真,得到倒置焊球的焊点高度及球径等焊点形态信息,并得出焊点失稳状态的极限重力条件。通过对SS面BGA焊点进行金相分析验证仿真结果,并对经过温度循环和振动试验后的SS面BGA混装焊点进行金相分析和染色试验。研究结果表明,当焊球承重较小时,随着焊球承重的增加,焊点高度呈线性增加;当焊球承重较大时,随着焊球承重的继续增大,焊点高度增加的速率加大。焊球直径为0.47 mm的BGA焊点,承重极限在0.0335 g~0.0389 g之间,焊点表面张力远大于器件自身的重力;SS面BGA混装焊点通过了200个温度循环及力学振动试验的考核。
For the remote data processing and transmission load of micro-satellite,new requirements such as miniaturization,intelligence,multifunction,and networking collaboration born.We need to solve the double-sided mounting technology problem of which is lead free BGA,such as flash/ddr and so on.Surface Evolver software is used to simulate the solder shape and state of the BGA package on the SS surface of PCB.The shape of the inverted solder ball,such as height and diameter,and the ultimate gravity condition of the instability solder joint were obtained.Metallographic analysis of the BGA solder joint on the SS surface of PCB was carried out to verify the simulation results.At the same time,metallographic analysis and dyeing test of the lead and lead free BGA solder joint on the SS surface of PCB was carried out after the temperature cycles and vibration test.The result show that when the load of the solder ball is small,the height of the solder joint increases linearly as the load of the solder ball increases.When the load is heavy relatively and creases continuously,the height of the solder joint increases heavily.The load-bearing limit of BGA solder(0.47 mm)is between 0.0335 g~0.0389 g.The surface tension of the solder joint is far greater than the weight of the package itself.The lead and lead free BGA solder joint on the SS surface have passed 200 temperature cycles and vibration test.
作者
李文建
刘潇
王晓博
郭瑞霞
翟海艳
贾亮
吴言沛
王宏
LI Wenjian;LIU Xiao;WANG Xiaobo;GUO Ruixia;ZHAI Haiyan;JIA Liang;WU Yanpei;WANG Hong(China Academy of Space Technology(Xi’an),Xi’an 710000,China)
出处
《空间电子技术》
2021年第6期99-105,共7页
Space Electronic Technology
基金
国家自然科学基金(编号:U1537207)。
关键词
BGA混装焊点
双面装焊
Surface
Evolver
可靠性
mixed Pb-free BGA/SnPb solder paste assemblies
double side reflow soldering
Surface Evolver
reliability
