Adhesion Study of Copper Layer Deposited onto Liquid Crystalline Polymer for Electronic Packaging

The adhesion of copper/liquid-crystalline polymer bilayer lamination structures with various thickness fabricated with chemical electroless copper deposition (CECD) and surfaced activated bonding (SAB) were characterized mechanical shear-off tests. The influence on the surface morphology and chemical state during different processes, including sulfuric acid bath, heat treatments, plasma treatments and moisture aging processes are studied with X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SAM). Thus the two fabrication methods are compared and potential methods to intensify the adhesion strength are present. The results are valuable for the future work aimed at achieving a LCP substrate based system-in-a-packaging (SiP) fabrication flow