Study On Total Dose Effect Of Three-dimensional Interconnection Structure Of Microsystem

With the development and maturity of three-dimensional integration technology,the interconnection structure represented by TSV is gradually applied to various electronic devices due to its advantages of high performance,small size,light weight and low cost.When applied in the space radiation environment,the interconnection structure is easily affected by the total dose of radiation due to its metal-oxide-semiconductor structure,causing device performance degradation and threatening the safe operation of aerospace equipment in orbit.Therefore,in order to study the influence of total dose irradiation on the performance of the interconnection structure,study its internal mechanism,optimize the interconnection structure to reduce the damage to it.The method of combining experiment and simulation is used to carry out the total dose irradiation research on the interconnection structure.(1)Three test samples are designed according to common interconnection structures.Under the condition of keeping its signal transmission structure unchanged,the design of the three structures is completed by changing the number of ground TSVs and the distance between ground TSVs and signal TSVs.After the three structures are determined,HFSS software is used to simulate and analyze the scattering parameters of the interconnect structure.The simulation results show that the three structures can meet the transmission requirements.After the actual samples were obtained,the scattering parameters of the interconnection structure before irradiation were measured using a vector network analyzer.(2)Carry out the total dose irradiation test research on the interconnection structure.60Co was used as the total dose irradiation source,and the irradiation dose was set to 180 krad(Si),240 krad(Si),300 krad(Si),420 krad(Si),540 krad(Si)and 720 krad(Si).After irradiation,the scattering parameters were measured with a vector network analyzer.The measurement results show that as the irradiation dose increases,the return loss of the interconnect structure increases,the insertion loss decreases,and the overall performance of signal transmission decreases.(3)Carry out the simulation study of the total dose irradiation on the interconnection structure.According to the parameter extraction method,each part of the interconnection structure is converted into electrical components,the equivalent circuit of the interconnection structure is built and simplified,and the total dose effect is simulated by adjusting the component parameters.The simulation results show that the increase of TSV equivalent resistance and the decrease of TSV equivalent capacitance are the reasons for the degradation of the signal transmission performance of the interconnect structure.(4)Carry out mechanism analysis for the total dose effect of the interconnection mechanism.Geant4 software is used to simulate the energy deposition of different parts of the interconnection structure.The simulation results show that the energy deposition in the interconnection structure from large to small is Si,Cu,Pi and SiO2.Combining with HFSS software for mechanism analysis,the results show that the total dose irradiation will lead to changes in the conductivity of copper and the dielectric constant of silicon and silicon dioxide in the interconnection structure,which will affect the internal parasitic resistance and parasitic capacitance of the interconnection structure,and further lead to the change of interconnection structure.The transmission performance of the connection structure is attenuated.In this paper,the total dose irradiation test results of the interconnect structure are given,and its internal mechanism is studied based on experiments and simulations.In addition,the interconnection structure is optimized to reduce the total dose radiation damage and make radiation result predictions.These research results can provide suggestions for the spatial application of interconnect structures in 3D integration technology,and provide advice for subsequent radiation-resistant hardening designs.