Research On Multi-Physics Model Of TSV Used In 3D Integration System

3D integration technology can effectively increase integration density,reduce interconnect length and achieve hetero-integration based on vertical stack.Through-silicon-via(TSV)technology is a key enabling technique for 3D integration and provides electrical interconnection,benifitting from lower latency,smaller parasitic capacitance and inductance,higher data communication speed.While 3D integration can enhance the integration density,the three dimensional integration suffers from more and more critical thermal reliability problems due to the increased power density per unit area.Meanwhile the thermal-mechanical reliability issue needs to be solved because the carrier mobility of the active devices can be affected by the induced thermal-mechanical stress resulting from the coefficient of thermal expansion mismatch between different materials during the TSV fabrication process in 3D integration technology.The reliability issue of TSV is a multi-physics based problem which needs to take thermal,electrical and mechanical reliability interactions at the same time under the medium frequency applications.This thesis centers the multi-physics reliability of TSV used in 3D integration and conducts a series of research work based on COMSOL Multiphysics finite element simulation software.The main research content includes:1.TSVs' thermal model as well as thermal management method for 3D integrated system are investigated;segmented thermal resistance model is used to investigate the impact of TSV parameters on steady state temperature of the 3D integration system and this segmented model is compared with one dimensional thermal resistance model and finite element simulation result to verify its advantages.Segmented thermal resistance model is used to guide the thermal management design of 3D integrated system.2.Thermal-mechanical reliability issue of TSV is investigated;The impact of TSV parameters on thermal stress and keep-out-zone(KOZ)under variant directions used for thermal TSV placement is analyzed;Three methods for improving the thermal-mechanical reliability is investigated and tapered TSV circumstance is considered.3.The effect of two physical fields coupling such as electrical-thermal and electrical-mechanical coupling on reliability is researched based on finite element software and make comparison between cylindrical and tapered TSV.4.Investigate the effect of electrical-thermal-mechanical three physical fields coupling on TSV reliability for two and four TSV arrays at the same time;The effect of various TSV placement method and assigned function on Von Mises stress distribution for Si substrate surface is researched and maximum peak stress under different current density versus TSV radius and TSV pitch is also given.