热应力影响下SCSP器件的界面分层

Interface delamination of SCSP device in thermal stress influence

通过有限元方法研究了堆叠芯片尺寸封装(SCSP)器件在回流焊工艺过程中的热应力分布,采用修正J积分方法计算其热应力集中处应变能释放率。结果表明:堆叠封装器件中最大热应力出现在Die3芯片悬置端。J积分最大值出现在位于Die3芯片的上沿与芯片粘结剂结合部,达到1.35×10–2J/mm2,表明该位置的裂纹处于不稳定状态;在Die3芯片下缘的节点18,19和顶层节点27三个连接处的J积分值为负值,说明该三处裂纹相对稳定,而不会开裂处于挤压状态。

The distribution of SCSP device＇s thermal stress during reflow soldering process was investigated through finite element method, and strain energy release rate of thermal stress concentration area was calculated by modified J integral method. Results show that maximum thermal stress of SCSP device appears in Die3 chip suspended tip. The maximum value of J integral locates the joint part of Die3 chip above verge and adhesive and arrives at 1.34 J/m^2, to show the crack in this location is unstable state. J integral values are negative values at three points （points 18, 19 of Die3 chip low verge and top point 27）, which means the cracks of three locations are relative stable; the crack is in the extrusion state, not to crack.