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塑料球栅阵列封装PBGA的可靠性分析中,考虑封装过程中SnAgCu焊料与铜焊盘界面间产生的金属间化合物(Intermetallic compound,IMC)的影响,并引入内聚力模型(Cohesive zone model,CZM),利用ANSYS对热循环作用下焊点/IMC界面的脱层开裂情况进行研究.结果表明:热循环作用下,在封装器件中焊点承受较大的应力应变,且远离中心的外侧焊点具有比内侧焊点更大的应力应变.IMC的存在极大的降低了焊点的可靠性.界面分层最先发生在最外侧的IMC/焊点界面的两端,随着热循环次数的增加,分层逐渐沿着界面两端向里扩展.在热循环的前几个阶段,各个界面的最大损伤值增大较快,随着热循环的继续加载,界面最大损伤值逐渐趋于稳定.整个过程中四号焊点界面的损伤值始终最大.
In the reliability analysis of plastic ball grid array (PBG) package PBGA, the effects of intermetallic compound (IMC) between SnAgCu solder and copper pad interface during the packaging process are considered, and the cohesive zone model (CZM) The thermal delamination and delamination of the solder joints / IMC interface under thermal cycling were studied by ANSYS.The results show that the solder joints under the thermal cycling are subject to large stress and strain, and the outer solder joints away from the center have the ratio The larger the stress and strain of the inner solder joint.The existence of IMC greatly reduces the reliability of the solder joint.The interface delamination first occurs at the outermost IMC / solder joint interface at both ends, with the increase of the number of thermal cycles, The delamination progressively expands along the two ends of the interface, and in the first few stages of thermal cycling, the maximum damage value of each interface increases rapidly, and as the thermal cycling continues to load, the maximum damage value of the interface gradually stabilizes. The process of welding spot No. 4 interface damage is always the largest.