CCGA焊点热循环加载条件下应力应变有限元分析

SMT焊点在热循环加载条件下的应力应变过程分析是 SMT焊点可靠性研究的重要内容。SMT焊点的可靠性问题主要是焊点在热循环过程中 ,由于陶瓷芯片载体与基板材料之间的热膨胀失配而导致焊点的蠕变疲劳失效。以 CCGA焊点为例 ,利用 CCGA三维焊点形态预测表面节点输出结果 ,将焊点形态分析三维表面模型转换为焊点应力应变有限元分析三维实体模型 ,从而建立了 CCGA焊点可靠性分析模型 ,采用三维有限元方法分析了 CCGA焊点在热循环条件下的应力应变过程。在此基础上 ,对 CCGA焊点疲劳寿命进行了计算

The FEM Analysis of Stress and Strain in CCGA Solder Joint Under the Thermal Cycle

The FEM analysis of stress and strain in solder joint process under the thermal cycle is one of the important aspects in the research field of solder joints reliability. The primary issue of SMT solder joint reliability is the creep fatigue failure due to the coefficient of thermal expansion (CTE) mismatch between the ceramic chip carrier and the substrate material under the thermal cycle. In this dissertation, an elasto plasto creep material model and its mechanical constitutive equation were described for SnPb solder alloy. By taking the CCGA solder joint as an example, and by taking an advantage of the modal output result of shape surface of CCGA 3 D solder joint, finally by converting the 3 D surface model of solder joint shape analysis to 3 D solid model of finite element analysis for stress and strain of solder joint, the CCGA solder joint reliability analysis model was established.Meanwhile the stress strain response of the CCGA solder joint under the thermal cycle was analyzed by using 3 D FEM. On the basis of this model, the thermal fatigue life of CCGA was calculated.