Argon and nitrogen plasma surface treatments of polyimide films for electroless copper plating

Argon and nitrogen plasma processes were applied to the surface treatment of polyimide films for electroless plating. The polyimide surface was exposed to Ar and N2 plasmas to improve the copper plating on the polyimide surface after KOH treatment. The chemical and the physical modifications of the KOH-treated polyimide surface caused by the plasma processing were charac-terized by using X-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). The formation of C=N bonds induced by the plasma treatment was shown to promote the adsorption of palladium, which in turn enhanced the bonding with copper. Microscale Cu line patterning was also demonstrated on a flexible polyimide substrate by using the micromolding-in-capillaries (MIMIC) patterning process.