Thermal properties of interconnects in power MOSFETs

Thermal conductivities of different interconnect sections of power MOSFETs were numerically determined using the Stationary Thermal Analysis mode of the ANSYS software. From the numerical solution, the thermal conductivities in the directions of the coordinate axes were calculated from the specified temperature difference on the opposite faces of the simulation box and the thermal flux through these faces as determined by the numerical solution. A strong anisotropy of the average thermal conductivity was found in the sections of the typical interconnect structures of power MOSFETs. Largest thermal conduction was observed in lateral directions along the metallic interconnect lines. The averaged thermal conductivities were provided to large-scale power MOSFET simulations to determine the temporal temperature evolution as response to a power pulse.