Study On The Propagation Characteristics Of Through-Silicon Vias Considering Temperature Effect

Due to the limitations of the physical limits,the development of two-dimensional integrated circuits is facing more and more challenges.Three-dimensional integrated circuit(3D IC)proposed recently become an effective way to continue Moore's Law.The essence of the 3D IC is to stack multiple homogeneous or heterogeneous chips in a vertical direction,and utilize Through-Silicon Via(TSV)to achieve inter-chip electrical connections.3D IC can significantly reduce the length of the global interconnect,descend the chip area,achieve heterogeneous integration and improve integration,but inevitably bring about a sharp increase in power consumption and chip temperature.As an important part of 3D IC,TSV in-depth study at different temperatures is of great significance.In this paper,the influence of temperature on TSV parasitic parameters and transmission characteristics is analyzed.The parameters model of TSV,including parasitic resistance,parasitic capacitance,parasitic inductance and substrate conductance,are established by analyzing its electromagnetic and temperature characteristics.In the temperature range of 300 ~ 400 K,the parasitic resistance is increased by 25% due to the increase of the resistivity.The dielectric capacitance and the intermetallic dielectric capacitance are not affected by the temperature because of the small change in the structure size and dielectric constant.The depleted capacitance is increased by 10% due to the decrease of the maximum depletion width.The substrate capacitance is also affected by the maximum depletion width,but the substrate capacitance is reduced by 0.7% due to the pitch of TSV is much larger than the depletion width.The internal inductance is related to the AC resistance,which takes parasitic inductance an increase of 0.4% at 400 K.The substrate conductance is reduced by 42% due to changes in substrate conductivity.The TSV equivalent circuit of Ground-Signal(GS)type and the transmission characteristics on different temperature are analyzed in the paper.The simulation results show that the high temperature transmission characteristic of TSV is improved at high frequency while deteriorated at low frequency.And based on that,the influence of TSV transmission characteristics on different structural parameters and temperature coupling is analyzed by using control variable method.The influence of the TSV transmission characteristics affected by structural parameters including TSV radius,medium thickness,TSV spacing,TSV height with temperature coupling is independent with each other.The effect of temperature on TSV will be highly reduced in high frequency but obscure at low frequency when the substrate concentration is low.The transmission characteristics of Ground-Signal-Ground(GSG)type TSV and air gap TSV were studied by establishing the equivalent circuit.The simulation result shows that the air gap TSV has been greatly improved due to the reduction of the dielectric capacitance.The trend of transmission characteristic curve on differnet temperature keeps align with the GS type.At low concentrations,the temperature has little effect on GSG type TSV transmission characteristics.When the concentration is same,among the three structures,GSG type TSV is significantly affected by temperature,while air gap TSV is the least.