A new electroless plating process for preparing a copper layer with strong adhesion to glass substrates was developed. This process incorporates a ZnO thin film on the glass substrate, instead of etching and sensitizing the substrate surface as in a conventional electroless plating process. The copper layer so obtained had a mirror-like finish while maintaining strong adhesion, even on a very smooth glass surface (Ra < 0.01 mum). The bond strength measured by pull tests was more than 1 0 kg per 2 mm x 2 mm square (kg/2 mmsquare), much greater than that obtained using conventional electroless plating (approximately 1 kg/2 mmsquare) and suitable for use in printed circuit boards. We find the ZnO thin film to serve as a kind of "adhesive" between the metal layer and glass substrate.