DEVELOPMENT OF FOAMED THERMOPLASTIC SUBSTRATE MATERIALS FOR PRINTED CIRCUIT BOARDS

摘要

This work focuses on the development of foamed high temperature thermoplastic substrates for printed circuit boards. An additive, in this case talc, is melt-compounded in polyetherimide (PEI) using a twin-screw extruder. Foamed samples are prepared by foam extrusion using CO_2 as physical blowing agent. The aim of the study is to analyse the influence of the additive on the foaming behaviour and the surface quality of the samples. The substrate materials were laminated with an adhesive film and a thin copper foil and subsequently the peel strength and the resulting surface quality are investigated and correlated to the substrate surface roughness, the adhesive film and copper foil thickness. The additive demonstrates a positive influence on the foam morphology, resulting in smaller cells, the surface roughness and the peel strength.