Effect of Plasma Gas onto Epoxy Mold Compound Adhesion within Heatsink Attach of Power Modules

Soldering or sintering as heatsink attach technology for large-area molded power modules is necessary within innovative high-performance packaging approaches but poses a special challenge to the epoxy-assembly interface throughout joining. Epoxy delamination around the etch trenches of the metal-ceramic-substrates has been deducted as general issue within heatsink attach. The plasma gas used for surface pre-treatment before epoxy encapsulation has been identified as a huge impact factor for epoxy adhesion performance throughout the attach process, delaminated surface area can differ up to $20 \%$ depending on plasma gas selection. Epoxy adhesion strength on the copper surface of the metal-ceramic-substrate has been characterized with the help of the method of shear button creation by laser ablation as well, showing similar sensitivity on chosen gas combination.