PLASMA-ETCHING OF THIN-LAYERS OF ORGANIC POLYMERS .8. PLASMA-ETCHING OF POLY(VINYL ALCOHOL)

Earlier hypotheses on particularities of oxygen plasma etching of poly(vinyl alcohol) (PVAL) are confirmed. Firstly, in difference to etching under O2-RIE conditions a decrease of the etching rate during polymer removal does not occur. Secondly, the activation energy of plamsa etching of poly(vinyl butyral) in contrast to PVAL does not depend on the polymer degradation process. These experimental results together with literature data confirm the assumption of a relatively thick "K-layer" on the polymer surface in oxygen plasmas. Degradation processes take place in the bulk polymer below this "K-layers". They are responsible for removal of the PVAL layers.