Surface characteristics of etched parylene-C films for low-damaged patterning process using inductively-coupled O-2/CHF3 gas plasma

Abstract

We investigated the effectiveness of CHF3 admixture in O-2 plasma for a low damage patterning process. We used inductively-coupled plasma (ICP) etching of parylene-C thin films with O-2/CHF3 gas mixtures. Plasma diagnostics were performed by using a double Langmuir probe. Also in order to examine the relationship between the plasma and surface energy, we attempted to conduct a simplified model-based analysis of the CHF3/O-2 plasma. The surface energy decreased as the admixture fraction increased with fluorocarbon containing gas. The decreased surface energy is related to the functional groups of CFx polymer at binding energy of around 290 eV and low ion physical damage. We observed that a small addition of CHF3 to O-2 plasma produced a high etch rate, low surface energy, and low roughness compared to pure oxygen plasma. (C) 2013 Elsevier B.V. All rights reserved.