摘要
本文采用有限元模拟的方法,对塑封焊球栅阵列PBGA的再回流焊接过程及其后的热循环进行了仿真,其中环氧模塑封装材料EMC采用了粘弹性和线弹性两种材料模式。仿真中主要对EMC再回流焊接过程产生的残余应力和热循环载荷下的热应力／应变进行了分析;也讨论了EMC材料模式对应力值的影响。结果表明:线弹性模式的EMC的应力值明显高于粘弹性模式的;在热循环载荷下EMC中应力水平并不高,但开裂应变却非常高,因此在EMC中很可能引发疲劳裂纹。
In this paper, the reflow soldering process and the following thermal cycles are modeled in a Plastic Ball Grid Array ( PBGA) using finite element analysis method.In the simulation, the Epoxy Molding Compound ( EMC ) is modeled as viscoelastic and elastic properties.Based on the simulation results, the reflow-induced residual stress and the thermal stress/strain during thermal cycling are analyzed and the material modes effect on the stress value in EMC is also investigated.The results show if the EMC is considered as elastic material, the stress level becomes higher.And the stress level in the EMC is not very high, but under thermal cycling condition, fatigue cracking may be initiated.
出处
《电子与封装》
2004年第6期26-29,共4页
Electronics & Packaging
