An Optimization Study with Batch Microwave Plasma was Done on Extra-Wide Leadframe Size to Achieve a Robust Result Against Delamination

In the field of Back-end manufacturing, plasma process is mainly used for cleaning, surface activation and adhesion improvements of substrates, either metallic or organic. For instance, the purpose of the pre-molding plasma on lead frame (LF) products is to improve the adhesion of the Epoxy Molding Compound (EMC) on different surfaces such as on the die, leads and die pads. Unbalanced cleaning results in poor homogeneity of the oxide removed from the lead frame surface. This further may cause the growth of complex at oxides at molding that eventually leads to delamination at the lead frame to EMC interface. The paper presents a new method of plasma modulation to enhance batch plasma homogeneity within the chamber. The work, based on the Design of Experiment (DOE), is performed with a pre-molding microwave (MW) plasma equipment on a extra-wide copper lead frame <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(100\text{mm x} \ 300\text{mm})$</tex>. A final validation, repeating the plasma twice, demonstrates that the presented work does not cause any damage to the fragile native oxide, resulting in no delamination at the reliability testing.