Influence Of Material Parameters On Stress And Deformation Of Interconnected Laminated Structures

High power semiconductor devices are widely used in different fields.Chip interconnect stack structure is the core structure.The intense temperature changes experienced by the laminated structures during packaging and service will lead to the accumulation of internal stress,strain and structural deformation.Material parameters(physical parameters and geometric parameters)have a significant effect on structural stress and deformation.Exploring the influence law is beneficial to improve the thermal reliability of laminated structures and prolong the service life of devices.The main research results of this paper are as follows:In this paper,a two-dimensional model of interconnected laminated structure was established.Combined with boundary condition processing and elasto-plastic optimization of interconnected materials,the analytical expression of the relationship between stress and deformation of interconnected laminated structure and material parameters was obtained,as well as the formulas of stress growth and strain accumulation of interconnected laminated structure under temperature cycle load.The results of analytical calculation and finite element simulation show that with the increase of thermal expansion coefficient of interconnect materials and the decrease of Young's modulus,the maximum stress and warping deformation of interconnect layers increase.The interconnection of the laminated structures of different interconnecting materials was carried out,the microscopic morphology of the interconnecting joints was observed,the warpage deformation of the laminated structures and the interconnecting bond strength were measured,and the influence law of the material physical property parameters on the warpage deformation and the residual stress of the interconnecting layers was analyzed by analytical calculation.The results show that the decrease of thermal expansion coefficient,the increase of Young's modulus and the decrease of yield stress can reduce the warping deformation of laminated structures and the residual stress of interconnect layers.The minimum warpage deformation of SAC305 interconnect structure is 4.68?m,and the minimum residual stress of nanosilver interconnect structure is 0.303 MPa.The decrease of residual stress is beneficial to improve the bonding strength of interconnect.Interconnection layer thickness,the thickness of the chip,chip based on the length of the single factor of the geometric parameters,such as welding experiment,combining analytic calculation analysis of geometric parameters on the buckling deformation laminated structure and interconnection layer the influence law of residual stress,the results show that increasing interconnection layer and chip thickness,reduce the chip length can reduce warping deformation and residual stress of the structure.