Influence of glass filler on peeling strength of electroplated circuit on polyamide substrates in MID

摘要

The adhesion strength between the circuit trace and the substrate is one of the important properties in MID (Molded Interconnect Device). In the conventional MID process, the adhesion strength depends on the anchor effect between the electroplated copper membrane and the substrate. But in the one-shot laser method, the adhesion strength mainly depends on the film bonding energy and the mechanical strength of the substrates. The optimal design of the substrate material must be done from this viewpoint and in such case, the design of the glass filler content is very important for higher adhesion. In this study, circuit traces with the electroplated copper film were formed on the molded polyamide plates with different filler contents by one-shot laser method, and the peeling strength of the circuit traces was measured. The peeling strength has decreased and the fracture aspect has changed as the glass filler content increased. The finite element stress analysis and the adhesive theory have clarified the point that the decrease of the substrate strength at the surface induced by the glass filler causes the peeling strength to decrease and the fracture mechanism to change.