Study on the Electrothermal Properties of Cu-CNT TSV Interconnects Under Multiphysics Field Coupling

In order to improve the electrical transmission and heat dissipation performance of through-silicon vias (TSVs) in high-frequency, high-density, and highly integrated environments, the electrothermal characteristics of copper-carbon nanotube (Cu-CNT) composites in TSV were explored in this study. The effects of temperature, carbon nanotube (CNT) diameter, and the proportion of CNTs in Cu-CNT composites on the electrical properties of TSV were analyzed using a TSV pair circuit model within an electrothermally coupled physical field. The results indicate that the electrical transmission performance of TSV is significantly affected by the number of conductive channels in CNTs. Temperature and CNT diameter can increase the number of conductive channels in individual CNTs, thereby enhancing the electrical transmission performance of TSV. Increasing the proportion of CNTs in Cu-CNT composites can reduce the resistance and inductance of TSV interconnections, thus enhancing the long-distance electrical transmission performance of TSV. The impurity concentration in the silicon substrate also affects its conductivity and capacitance, thereby impacting the electrical transmission performance of TSV. In an electrothermal coupling environment, thermal performance testing was conducted on TSV made of Cu-CNT composite materials. The results reveal that CNTs can reduce the grain size of the composite and increase the dislocation density, thereby effectively reducing TSV protrusion displacement. In addition, the Cu-CNT composite material demonstrates excellent thermal conductivity and a thermal expansion coefficient that is well matched with the silicon substrate, which will make a decrease in the maximum temperature of TSV and an improvement in reliability. These findings suggest that Cu-CNT composite materials are expected to become an excellent filling material of TSV for solving high-density stacking, long-distance transmission, and high heat issues in 3-D integrated circuits (3-D ICs).