Parasitic Parameters Extraction And Equivalent Circuit Establishment For Novel Through-silicon Vias

With the development of the transistor density and roughly function density in integrated circuit?IC?due to the continuous dimension scaling of transistor,the delay and crosstalk caused by the interconnect lines are becoming more and more significant for the IC performance.The three-dimensional?3D?technique,staking many different chips vertically with the Through-Silicon Via?TSV?for the electrical interconnect,can effectively scale the interconnect length,reduce the chip area and increase the density,and realize the development of microelectronics products towards miniaturization,high integration,high performance and low cost,which makes it very important for the further development of the microelectronics.As the TSV is the most important core of the 3D technique,an analysis on a novel TSV structure has been carried out in this paper.Based on the tapered and annular TSV structures,a new tapered-annular TSV structure is proposed and an equivalent circuit model is also developed.The parasitic parameters such as the resistance,inductance and capacitance are extracted.The excellent agreement is obtained by the comparison of the modeling results with the Advanced Design System?ADS?simulation and the High Frequency Structure Simulator?HFSS?full-wave simulation,verifying the validation of the proposed model.The proposed tapered-annular TSV structure is optimized based on the impacts of the TSV structure parameters such as the height,the metal thickness and the substrates conduction on the signal transmission.The comparison study is also carried out and the results show that the optimized structure with return loss of-47dB and insertion loss of-0.045dB exhibits improved performance compared with the un-optimized structure with return loss of-28dB and insertion loss of-0.3dB.Based on tapered-annular TSV structure,air-gap TSV and tapered-coaxial TSV are formed by changing the dielectric material and structure.The impact of the isolation medium of air and SiO₂ on the characteristic of the proposed structure is investigated and compared at20GHz.The results turn out that with return loss of-32.5dB and insertion loss of-0.15dB,the structure with air isolation exhibits much better performance for the high frequency signal transmission than the structure with SiO₂ isolation.The tapered-coaxial structure with the conductive metal surrounded by an out layer of shield metal which can shield the noisy signal for further improving high frequency characteristic and reliability,is also proposed and optimized for the isolation medium,the height and the metal radius.