Effects of the surface modification by remote hydrogen plasma on adhesion in the electroless copper/tetrafluoroethylene-hexafluoropropylene copolymer (FEP) system

FEP sheets were modified with a remote hydrogen plasma and the effects of the modification on the adhesion between copper metal and FEP sheets were investigated. The remote hydrogen plasma treatment is able to make FEP surfaces hydrophilic. In the remote hydrogen plasma treatment process, both defluorination and oxidation occur on the FEP surface. The oxidation reactions on the FEP surface form oxygen functional groups such as C-O and C=O groups. Modification of the FEP surface by the remote hydrogen plasma is effective in improving the adhesion of copper metal. The peel strength of the Cu/FEP system increased form 0 to 195 mN/5 mm, and the failure mode changed from the Cu metal/FEP polymer interface to within the FEP polymer layer. Remote hydrogen plasma treatment may be a preferable pretreatment of the FEP surface for adhesion with copper metal.