Novel in-situ button shear methodology for efficient assessment of mold compound encapsulation

To investigate the adhesion properties of the Epoxy Molding Compound (EMC) applied as encapsulation in the power module packaging, a novel button shear test method was designed. This novel characterization method enables to assess the molding process quality and product quality over different location of the mold body on the final product. It opens new field of investigations such as the impact of pre-conditioning, EMC flow and material homogeneity after molding on the adhesion over the product. In this study the integrity of the EMC buttons prepared by laser ablation on copper and nickel surfaces are investigated by cross section analysis. Then the validation of the methodology is demonstrated through comparison of standard and novel in-situ methods. To test the novel method in application, positive impact of Argon plasma preconditioning (before molding) on the EMC's adhesive strength & failure mode type is illustrated.