Electroless deposition of copper on poly(tetrafluoroethylene) films modified by plasma-induced surface grafting of poly(4-vinylpyridine)

Argon plasma-pretreated poly(tetrafluoroethylene) (PTFE) films were solution coated with a thin layer of poly(4-vinyl pyridine) (P4VP). Subsequent exposure of the films to argon plasma resulted in the grafting of P4VP on the PTFE films. Electroless plating of copper could be carried out effectively on the P4VP-grafted PTFE (P4VP-g-PTFE) surface after PdCl2 activation and in the absence of SnCl2 sensitization (the Sn-free process). The catalytic processes of the electroless plating of copper in the presence and absence of sensitization by SnCl2 were also compared. The effect of glow discharge conditions on the P4VP concentration and the adhesion strength of the electrolessly deposited copper was investigated. The T-peel adhesion strength of the electrolessly deposited copper with the graft-modified PTFE film was improved in the absence of SnCl2 sensitization and could reach about 3 N/cm. PdCl2 activation and electroless deposition of copper could not be carried out on the pristine or the At plasma-treated PTFE surface in the absence of prior sensitization by SnCl2. X-ray photoelectron spectroscopic (XPS) analysis revealed that the electrolessly deposited copper delaminated from the P4VP-g-PTFE film by cohesive failure inside the PTFE film.