Factors Affecting the Adhesion of Fluoropolymer Composites to Commercial Copper Foils

Polytetrafluoroethylene (PTFE) films containing glass fillers have been shown to be promising materials in the development of high speed microelectronic packaging applications. Printed circuit board (PCB) manufacturing requires the use of copper foils that typically contain some surface modification for adhesion enhancement. The surface treatments of copper foils vary in composition and morphology. This study evaluates their chemical and physical characteristics before and after lamination to commercially available fluoropolymer dielectric films containing two different types of glass fillers. The peel strengths of the resulting interfaces are followed before and after PCB fabrication. The roles of surface composition, surface roughness, and fluoropolymer filler type are described in terms of the resulting adhesion of the metal/polymer interfaces.