A new approach to the copper/epoxy joint using atmospheric pressure glow discharge

A new approach for adhering copper to an epoxy resin was studied. In this new approach, the copper surface was first treated with hydrogen plasma generated by the atmospheric pressure glow (APG) discharge. Then a thin film of gamma-aminopropyltriethoxysilane (gamma-APS) was formed on the treated copper surface. The copper oxide formed by air on the copper surface deteriorated the adhesion by forming a weak boundary layer, part of which could separate from the surface. This oxide layer was reduced when an APG hydrogen plasma was applied for a couple of minutes at a frequency of 13.56 MHz and a power input of 200 W. The resulting peel strength at the copper/epoxy interface increased up to ca. 0.9 Kg/cm. Curing temperature of gamma-APS was also an important factor in obtaining good adhesion at the copper/epoxy interface, with the highest value of peel strength occurring at a curing temperature of 120 degrees C.