Selective metallization of flexible substrates by inkjet printing with electroless copper plating

G Barral (1) , N Hanifi (1) , R. Faddoul (2) , P. Viel (1)

1 LICSEN UMR 3685 - Laboratoire Innovation en Chimie des Surfaces et NanoSciences
2 Genes’Ink

A new efficient approach for selective metallization of flexible substrates such as poly(ethyleneterephtalate) (PET) sheets has been developed (Figure 1). The method is based on the covalent grafting of a chelating polymer film poly-4-vinylpyridine (P4VP) able to complex metallic palladium ions which then serve as catalyst for a copper electroless plating step. A solution of P4VP containing the palladium ions (II) catalyst is firstly inkjet printed to form a metallization primer. This primer is then photo-grafted onto the surface using a flashlamp. By a photo-oxidation process, light allows the formation of free radicals on the P4VP layer in contact with the substrate. Thus, covalent adhesion between the substrate and the P4VP is achieved. A selective copper layer is finally grown on the activated primer by a copper electroless plating process. The grafted primer layer enhances the copper adhesion. A resistivity-measured with four probes-as low as 2.1 µΩ.cm (sheet resistance equivalent to 84 mΩ/□ for 250 nm thickness) is obtained, which is only 20% higher than the one of bulk copper. This new low-temperature process only requires a plating bath and is thus compatible with low-cost thermally unstable flexible polymer substrates and R2R printing processes. The final metallic layer notably shows a very good adhesion on PET substrate and good stability in ambient atmosphere.

Mots clés: copper electroless plating; inkjet printing; printed electronics; flexible substrate; antenna

Domaines: Matériaux

G Barral, N Hanifi, R. Faddoul, P. Viel. Selective metallization of flexible substrates by inkjet printing with electroless copper plating. Materials 2017, Apr 2017, Aveiro, Portugal. ⟨cea-02342006⟩