Validation of etching model of polypropylene layers exposed to argon plasmas

Abstract

AbstractThin layers of polypropylene (PP) have been treated by argon low‐temperature plasmas in an inductively coupled plasma setup. The etched thickness of PP was monitored in situ by means of single‐wavelength ellipsometry. The ellipsometric model of the polymer surface exposed to plasma consists of a UV‐modified layer, a dense amorphous carbon layer because of ion bombardment, and an effective medium approximation layer, which accounts for moderate surface roughness. The etching behavior has been compared to a model based on argon ion beam irradiation experiments. In this approach, surface processes are described in terms of etching yields and crosslinking probabilities as a function of incident fluxes and energies of Ar ions and UV photons. The ion beam model fits well with the plasma etching results.