Research On Stress Reliability Of 3D Microsystem

In recent years,the integrated circuit industry has developed rapidly,and Moore's law has reached its bottleneck.3D integration technology is generally considered a powerful solution to continue Moore's law in today's world.At present,it has been able to realize complex 3D integrated circuits with small shape factors,high density and excellent performance,opening the door of traditional chip structure to the world of optimized shape and size.However,with the improvement of integration and power density of the 3D integrated microsystem,thermal characteristics and stress reliability are faced with many challenges.With the reduction of microsystem size,the complexity of finite element numerical simulation of the 3D integrated microsystem at package level will be further increased.Therefore,the thermal stress reliability analysis of the system is imperative.To solve the problems above,this paper aims at three-dimensional integrated microsystem,realizes the rapid stress analysis of the microsystem by establishing the equivalent finite element model,and obtains the change law of the stress with each parameter through the control variable method,which can effectively realize the stress analysis and life prediction of the microsystem,and provides theoretical guidance for the layout design of the microsystem chip.In this paper,the stress analysis of a single interconnect micro bump structure in the microsystem is carried out,and the stress variation law is analyzed by changing the shape parameters or the surrounding structure.The simulation results show that the simulation time of the proposed method is about 74% less than that of the traditional finite element model,and the deviation of the maximum strain is only about 5%.Then the creep performance and fatigue life of the micro bump structure in three-dimensional system are studied by using the equivalent modeling method proposed in this paper.The creep performance changes of the micro bump structure with different structural parameters are compared,and the fatigue life distribution of the micro bump array is analyzed.Finally,the life of the structure is optimized.Finally,aiming at the stress problem of three-dimensional integrated microsystem,this paper proposes a dielectric layer structure for stress buffer around the micro bump structure.The simulation results show that the structure has a good stress relief effect.The results show that the proposed stress buffer layer structure can reduce the maximum stress of the micro bump structure by about 18.9%,which improves the mechanical properties of the whole microsystem.