Etching mechanisms of PPS polymer with oxygen radicals

Abstract

Summary form only given. The weakly ionized oxygen plasma is nowadays frequently used for activation and etching of polymers or different polymer-matrix composite surfaces. In this process the topmost layer is activated and etched. In this process the efficiency and role of different oxygen plasma radicals, such as neutral atoms, ions and metastable radicals was studied. The etching mechanisms were studied on oxidation resistant polymer PPS (poly(p-phenylene sulfide)) and polymer-matrix composite with graphite, usually used in electronics devices. The polymer samples were exposed to RF (27.12 MHz) generated inductive coupled oxygen plasma at plasma parameters controlled by catalytic and Langmuir probes, supported by optical emission spectroscopy. The plasma setup was changed according to plasma species designated for interaction. The surface effects of plasma treatment were measured by wettability angle of deionized water drop, surface roughness with Taylor-Hobson, SEM and XPS analysis. Results show that at the beginning of the plasma polymer treatment process, metastable radicals and ions play important role in surface activation. But the etching is done mostly by neutral oxygen atoms. The second most important parameter in plasma etching, beside neutral atom density is surface temperature. The polymer etching can be therefore also controlled by ion density and the average kinetic energy