Electroless copper plating on 1,2-ethylenediamine grafted poly(ethyleneterepthalate) for the fabrication of flexible copper clad laminate

Abstract

An efficient method for the fabrication of flexible copper clad laminate (FCCL) on poly(ethyleneterepthalate) (PET) sheet by electroless plating was developed. This method relies on PET surface grafted 1,2-ethylenediamine (EDA) layer, which is employed as an adhesive interlayer for the manufacture of FCCL. Au catalysts were adsorbed on the EDA treated PET sheet and subsequently initiate the deposition of copper in an electroless plating solution. Attenuated total reflection fourier transformation infrared (ATR-FT-IR) spectroscopy, water contact angle, X-ray photoelectron spectroscopy, and atomic force microscope were employed to trace the surface changes during the grafting process with water, ethanol or dimethyl sulfoxide (DMSO) as solvent. For the PET sheets grafted from ethanol and DMSO solution, the prepared copper layers show strong adhesion to the substrate, which can pass Scotch^® tape test, while the sample grafted from water solution fail. All results indicate that using ethanol or DMSO as solvent for EDA grafting is benefit for the preparation of FCCL, and the adhesive improvements are due to an increase in the surface roughness of PET sheets and the amount of gold particles adsorbed on PET surface which act as nucleation and anchor sites for copper.