Numerical Simulation Of Reliability Of 2.5D/3D Package Interconnect Structure Under Temperature Cyclic Load

Due to the high bandwidth,high integration and high performance requirements of the electronics industry,2.5D/3D packaging technology has been developed rapidly.The 2.5D/3D packaging interconnection structure based on TSV(Through Silicon Vias)not only brings advantages such as reduced volume size and reduced power consumption,but also faces the problems of thermal effect and structural reliability.Based on ANSYS finite element simulation platform,this paper studied the structure and the solder joint reliability of 2.5D/3D package under temperature cycle load,established 2.5D and 3D package structure models respectively,and carried out simulation calculation based on JEDEC(Joint Electron Device Engineering Council)temperature cycle standard applied load.The deformation,stress and strain of the 2.5D/3D package structure and the solder joint life during the temperature cycling test were studied.Meanwhile,the reliability of the solder joint with and without lead in the 2.5D package structure under the temperature cycling load was compared.The results show that during the temperature cycle,the 2.5d /3D packaging structure has periodic warping deformation due to the difference of thermal expansion coefficient.In the process of rising and cooling,the deformation of the structure gradually increases along the positive and negative direction of Z,and reaches a large value at the lowest and highest temperature.It is found that the deformation amplitude of the two structures is significantly different in the process of temperature cycle.The equivalent stress and plastic strain of the solder joints of the package structure change periodically.The equivalent stress of the solder joints reaches the maximum when the temperature drops to the lowest and the plastic strain reaches the maximum when the temperature rises to the highest.The stress-strain level dangerous solder joints of the two packaging structures are located at the interface between the outermost solder joints and the substrate.The stresses of the dangerous solder joints of the two structures are almost similar.After the temperature cycle,the accumulated plastic strain of the dangerous solder joints is significantly different.The accumulated plastic strain of the dangerous solder joints of the 2.5D package structure is greater.The existence of TSV results in a great difference in the stress variation rule and value between the two package chips during the temperature cycle,and the chip stress level in 3D package is higher.Prediction of solder joint life found that the solder joint life in 3D package structure is higher under temperature cycle test.The results show that the equivalent stress of solder joints changes periodically during the temperature cycle,and the maximum equivalent stress of solder joints increases gradually with the increase of the number of cycles.In the same package structure,the solder joints of the lower layer is greater than that of the upper layer.Co MPared with the two packages,the stress of lead-free solder joints is greater than that of lead-free solder joints.The accumulated plastic strain of leadfree solder joints is less than that of lead-free solder joints after cyclic loading.Predicting solder joint life found that solder joints with lead had a higher lifetime in temperature cycling test.