Specialized Lead Design of Leadframe Packages for Improved Mold Adhesion

This paper presents an advanced design of Quad-Flat No-leads (QFN) and Quad-Flat Package (QFP) leadframe to mitigate the propagation of delamination between high stress level areas particularly the mold-to-leads interface. The integration of through-hole mechanism on leadframe provides mechanical anchoring of mold material to the lead junction interface and/or vice versa. To produce interlocking, the through-hole design will be penetrated by the epoxy mold compound during conventional molding process affixing each individual lead to the encapsulation material. On the other hand, the package design is materialized through repeated cycle of chemical etching and masking process during leadframe manufacturing, the mechanical anchoring can be implemented on the conventional design of carriers. This approach, considering the design and assembly method of the new leadframe design, is a cost-effective alternative in improving the interfaces of key material such as mold and leadframe.