Thermal Analysis And Simulation For Three Dimensional Heterogeneous Integration And Packaging Of Power MMICs

With the rapid development of modern electronic products,electronic products have shown a trend of increasing packaging density,miniaturization and diversification of the environment.Because of the high density interconnection between devices,the power density of packaging is greatly increased,which lead to the increase of thermal generation rate inevitably.The thermal problem will affect the normal operation of electronic devices,reduce the reliability of the devices seriously,and even lead to devices failure directly.Therefore,the thermal management problem has become a huge challenge for the development of electronic products.There are many finite element simulation softwares for thermal analysis.These softwares have high accuracy in solving temperature distributions,however the processes of modeling,meshing and solving are complex,which take up a lot of time and computer resources.Therefore,it is of great significance to study an analytical method that can solve the packaging temperature distributions efficiently.Because of the serious thermal problem of high density integrated packaging,it is necessary to choose the appropriate cooling measures,a heat sink is usually used for effective heat dissipation.The heat dissipation systems usually have different geometric dimensions from the packagings structure.The thermal analytic model presented in this paper describes a multi-layer packaging structure with different geometric dimensions.It is based on the heat conduction equation under the steady state,and then the temperature distribution of each layer of the packaging structure is determined analytically by using the iterative approximation method.The analytical method can evaluate the temperature characteristics of packaging effectively,and it can provide great help for thermal designers in thermal design.In this paper,a cascading power monolithic microwave integrated circuit(MMIC)packaging was fabricated based on the embedded package process of photosensitive benzocyclobutene(BCB).Based on this packaging model,a simulation model was built in the finite element simulation software ANSYS,and the temperature characteristics of the packaging model were solved under two different boundary conditions.At the same time,the analytical method proposed in this paper was used for the packaging model.The model was simplified and solved according to the reasonable equivalent method,and the calculated results were compared with the simulation results.By comparison,it was found that the calculation results and the simulation results are in good agreement under two different boundary conditions,which proved that the proposed analytical method has high applicability and reliability.