Improved Packaging of Power Module With Low-Permittivity Material for Low Common-Mode Noise and High Reliability

This article proposes a novel power module configuration which replaces a part of the bottom copper layer of a direct-bonded copper by low-permittivity (low-ϵ) epoxy. The proposed power module reduced common-mode (CM) capacitance by 52.5% compared to that of the conventional counterpart. The CM noise measured from line impedance stabilization network was reduced by 4–5 dBμV in steady-state operation. The proposed power module does not sacrifice thermal performance which is proved by simulation and thermal resistance measurement. Thermal cycling tests confirmed high mechanical reliability with no cracks in the solder near the epoxy region. Less mechanical deformation of 5.80 μm was observed compared to the 9.48 μm of the power module that adopts air instead of low-ϵ epoxy.