Electromagnetic Interference Analysis And Protection Design Of Three Dimensional Packages

With the integration of traditional two-dimensional integrated circuit increasing,delay and power consumption of metal interconnect have became the main restricting factor of IC's performance improvement.Three-dimensional(3D)package is expected to continue the development trend of miniaturization,multi-functional,high-speed and high-integration.On the other hand,as a kind of heterogeneous integration solution,3D package mixs semiconductor material,insulation material,metal material and alloy material.As a result,the internal electromagnetic environment of 3D package is extremely terrible.The superimposition of external electromagnetic emission radiated by multiple radiation sources in 3D package will strengthen the total radiation intensity,resulting in electromagnetic interference between encapsulation body and external circuit.So the electromagnetic compatibility(EMC)problems of "interference inside package" and "interference outside package" become one of the key research topics.Aiming at the electromagnetic interference and radiation problems of 3D package,the research contents of this paper are mainly contraposing accurate electromagnetic modeling of 3D package and electromagnetic shielding structure design,and the obtained innovative results are as follows:First of all,as for the EMC problems of "interference inside package",equiyalent circuit models of through silicon vias(TSVs)and horizontal redistribution layer(RDL)are proposed to facilitate the intuitive understanding of physical structure and material parameters' effect on electromagnetic characteristics of TSV in 3D package.To solve the difficulty of long simulation time when modeling large-scale TSV/through glass via(TGV)arrays in 3D package,precise field-circuit co-simulation method is proposed.The scattering matrix based method gives full consideration of multiple reflections and scattering between TSV/TGV arrays.Simulation and experiment results show that the method can effectively analyze the electromagnetic properties of large-scale TSV/TGV arrays.And compared to existing electromagnetic simulation softwares,computation time of the proposed method is greatly reduced.Secondly,to solve the modeling difficulty and huge computational burden when analyzing the "interference outside package" EMC problem,equivalent radiation source method is proposed.Equivalent dipoles are used to characterize electromagnetic radiation characteristics of 3D package in the equivalent radiation source method.According to the results of the near-field scanning,the method can be divided into amplitude and phase near-field scanning based equivalent radiation source method and phase-less near-field scanning based equivalent radiation source method.Regularization method is used to determine the equivalent dipoles in the amplitude and phase near-field scanning based equivalent radiation source method,and 3D full-wave simulator is combined to analyze the electromagnetic interference with peripheral circuit.Differential evolution(DE)algorithm is proposed to solve the nonlinear optimization problems in phase-less near-field scanning based equivalent radiation source method.Software for equivalent radiation source reconstruction is developed based on the proposed method and can be used for EMC analysis of intelligent mobile phone.The equivalent radiation source can accurately analyze electromagnetic radiation characteristics of a module in mobile phone,and relationship between accuracy of equivalent radiation source and the number of dipoles is explored.Verification results of clock circuit in mobile phone/base station show that radiation characteristic of equivalent radiation source has good consistency with the original clock chip.The maximum error of the coupling power at victim antennas between simulation and measured results is less than 6 dBm,and optimization time of DE algorithm is only 64 seconds for 10 dipoles.Finally,based on deep research of electromagnetic interference and radiation characteristics of 3D package,double-shielded interposer structure is proposed.Equivalent circuit model is deduced for the structure and its accuracy is verified.Compared to traditional TSV transmission structures,the proposed electromagnetic shielding structure has lower insertion loss and metal dielectric loss.Hence,the proposed structure can effectively improve signal transmission characteristics of TSV and reduce electromagnetic coupling in 3D package.