Mechanical and Dielectric Properties of Low Permittivity Dielectric Materials

Abstract

AbstractThe dielectric and mechanical properties of low permittivity dielectric/metal system consisting of fluoropolymers and copper were studied. The types of polymers in this study include sputtered Teflon, plasma-deposited fluoropolymers and the soluble Teflon AF1600. All these fluoropolymers have dielectric constants below 2.0 and dissipation factors below 0.001. Copper was either evaporated or sputtered. Adhesion of copper to fluoropolymers was studied using scratch and peel tests. Different thermal treatment techniques were applied to enhance adhesion, including preannealing in vacuum or in atmosphere, as well as postannealing in vacuum. The results show generally poor adhesion for evaporated copper, with substantial improvement for sputtered copper; however thermal treatments enhance adhesion in some cases. FTIR, surface tension and XPS experiments were carried out in an effort to understand these effects. Our findings will be discussed in terms of the various effects contributing to copper/fluoropolymer adhesion.