Study On Temperature Field Simulation Of System In Packages

With the System-in-package(SiP),a large number of active or passive electronic components with different functions have been integrated in the same structure to achieve multi-functional package structure.SiP has become mainstream packaging technology in microelectronics industry.With the development of SiP technology and continuous miniaturization of electronic components,integration density of SiP structure is increasing sharply.Consequently,thermal characterization of SiP becomes more and more complicated,which leads to many challenges to the analysis and design of SiP.Thus,fast and accurate modeling and simulation of thermal objections are very important to design of circuit systems.This thesis studies on the fast algorithms of three-dimensional thermal simulation.Thelatency insertion method(LIM)and alternating directionimplicit(ADI)method are employed for the steady-state and transientsimulations of temperature field in SiP,respectively.Similar to the finite-difference time-domain method in computational electromagnetic,LIM is an iterative algorithm.The key idea of LIM is to insert a fictional inductance or a capacitive in each branch or node to generate latency in the equivalent thermal network.The main feature of this method is that it avoids constructing and solving a large matrix,which reduces computational resources and improves efficiency and accuracy.For transient thermal simulation,the ADI approach is utilized.Instead of solving the original discredited heat conduction equation directly,the equation will be transferred into a succession of three one-dimensional equations in each time step.Then,the method with linear computational complex(e.g.follow-up algorithm)is employed to solve them one by one.Since the ADI method avoids solving the original complicated equation,the computational resources are reduced significantly and it holds the linear computational complex.Compared with traditional methods,it is much more efficient.In addition,the ADI approach is unconditionally stable.From the numerical examples and compared with the simulating results of COMSOL,the accuracy and efficient of both LIM and ADI approaches are fully demonstrated.