A Comprehensive Evaluation of Al Heavy Wire Bonding and Ribbon Bonding Application in high power WBG Power Modules

Targeting at a comprehensive Multiphysics evaluation for Al wire and ribbon bonding technologies for WBG power module, this paper investigates and compares the stray inductance, heat dissipation and fatigue life between these two bonding schemes in an XHP packaging designed in house. During calculation, it was tried to keep equivalent volume for the Al ribbon when substituting local Al wires for fair comparison. Results of stray inductance show extremely limit bonding-type dependence in ranges from 1 kHz to 10 MHz, and further expanding ribbon size to varied levels still presents negligible impact. The two bonding technologies do not prove their capability in sharing either static or transient thermal loads when the baseplate bottom is efficiently liquid cooled. Detailed study confirms that heat dissipates dominantly in vertical direction to the Cu baseplate rather than through Al bonds. Ultimately, the only noticeable benefit of Al ribbon in our multiscale analysis is its improved reliability during temperature cycling, with data supporting a 2.17× times longer lifetime of Al ribbon when comparing to its Al wire counterpart.