SCSP中芯片黏结层在焊接时的可靠性

Reliability of the die attach film in stacked chip scale package during solder reflow

提出了一个细观力学模型,该模型同时考虑了热膨胀和蒸汽膨胀对叠层芯片尺寸封装(SCSP)中芯片黏结层变形的影响。当初始温度确定时,由该模型可求得给定温度下芯片黏结层内部的蒸汽压力和孔隙率,从而判断芯片黏结层在焊接回流时的可靠性。当温度从100℃升高到250℃时,芯片黏结层的饱和蒸汽压、等效弹性模量及孔隙率分别从0.10 MPa、925 MPa、0.030变到了3.98 MPa、10 MPa、0.037。分析表明:饱和蒸汽压和高温下弹性模量的降低,均易导致芯片黏结层材料失效。

A micromechanical model was proposed,in which the effects of both thermal expansion and vapor pressure on the deformation of the die attach film in stacked chip scale package（SCSP） were taken into consideration.Both the vapor pressure and porosity of the die attach film at a specified temperature can be obtained with this model when the initial condition is known,and hence the reliability of the die attach film during solder reflow can be evaluated using this model.When temperature increases from 100 ℃ to 250 ℃,the saturated vapor pressure,equivalent elastic modulus and porosity of the die attach film change from 0.10 Mpa,925 Mpa and 0.030 to 3.98 Mpa,10 Mpa and 0.037,respectively.Analysis shows that reductions in both the saturated vapor pressure and elastic modulus at high temperature tend to result in die attach film material failure.