Effect of Ni-Cr Layer on Adhesion Strength of Flexible Copper Clad Laminate

In this study, the effect of a Ni-Cr layer on the adhesion strength of flexible copper clad laminate (FCCL) was evaluated after thermal treatment. The changes in the chemical composition, morphology, and adhesion properties were characterized by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and 90 deg peel test. The results showed that both the peel strength and thermal resistance of the FCCL increased with increasing Cr ratio. The thermal treatment of the FCCL increased the proportion of C-N bonds and reduced that of the C-O and carbonyl (C=O) bonds in the polyimide. The roughness of the fracture surface decreased with increasing thermal treatment temperature and holding time. The chemical function and roughness of the fracture surface were affected by the Ni-to-Cr ratio.