A laser curable palladium complex ink used for fabrication of copper pattern on polyimide substrate

A simple and efficient approach for selective metallization of polyimide (PI) substrate has been developed in this work. A heat curable Pd complex ink consists of Pd salt, pH sensitive monomer N, N-dimethyl-dimethylaminoethyl methacrylate (DMAEMA), trimethylolpropane triacrylate (TMPTA), and tert-butyl peroxybenzoate (TBPB) is utilized to promote the adhesion between the Cu coating and PI substrate. After heating the spin-coated ink on PI and successive electroless deposition (ELD) of copper, a layer of copper with excellent adhesion is formed on PI substrate. The effects of this ink on catalyzing the ELD of copper and the mechanism for the enhancement of the adhesion between flexible PI substrate and copper layer are investigated by XPS and FT-IR. The copper coating plated by this method has a low resistivity (about 13.6 x 10(-6) Omega cm) and satisfied endurance of bending. Moreover, we also demonstrate that the copper patterns can be prepared easily by integration of laser-direct patterning of the spin-coated ink and electroless Cu deposition, which is fast and effective strategy for fabricating circuit patterns on the plastic substrate. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.