PLASMA-ETCHING OF THIN-LAYERS OF ORGANIC POLYMERS .4. POLY(VINYL ALCOHOL)

At the investigation of oxygen plasma etching of poly(vinyl alcohol) some peculiarities have been found. Based on the etching kinetics, the formation of a thick, but not very stable, "K-layer" is assumed. The molecular structure of this modified layer may consist of some sections of conjugated double bonds within the polymer chain, graphitic and oxidized carbon, and crosslinked chains. From the unusual temperature dependence of the etching rate the existence of two competitive reactions is concluded. One reaction leads to degradation, the other to crosslinking of the macro-molecules.