Open-air-type Ar + H2O plasma treatment of polytetrafluoroethylene for improving Ag/PTFE adhesion strength: application to highly adhesive Ag direct wiring patterns

Abstract We performed an open-air-type plasma treatment of polytetrafluoroethylene (PTFE) at atmospheric pressure to increase the adhesion strength between PTFE and an Ag metal film obtained from Ag ink. When PTFE was Ar plasma-treated without H 2 O addition for 600 s, the coloration of the PTFE surface occurred, and the Ag/PTFE adhesion strength was 0.06 N mm −1 . This adhesion strength was the same as that of the as-received PTFE (0.04 N mm −1 ). When the PTFE was Ar plasma-treated with the H 2 O addition of ca. 0.1% for 600 s, coloration did not occur, and the Ag/PTFE adhesion strength increased to 1.03 N mm −1 . The effects of H 2 O addition to the Ar plasma on the Ag/PTFE adhesion strength, surface chemical composition, surface morphology, and the surface hardness were investigated and discussed in this study.