Plasma Enhanced Chemical Vapor Deposition of Poly(Cyclohexyl Methacrylate) as a Sacrificial Thin Film

Abstract

In this study, thin films of poly(cyclohexyl methacrylate) (PCHMA) were deposited on silicon wafer using PECVD technique, in which the plasma power is inductively coupled through a quartz window using a planar-coil antenna, which was placed outside of the vacuum chamber. PCHMA is a desired sacrificial polymer for many applications because of its hydrophobicity and clean decomposition properties upon thermal annealing. During PECVD of PCHMA, the effects of plasma power and substrate temperature on the deposition rates and structural properties of as-deposited films were investigated. The highest deposition rate (46.5 nm/min) was observed at a low substrate temperature (15 degrees C) and at a high applied plasma power (30 W). FTIR and XPS analyses of the deposited films confirmed that the percentage of retained functional groups was increased if the intensity of applied plasma power was lowered. As-deposited PCHMA was found to decompose cleanly upon thermal annealing. The onset of thermal decomposition was 89 degrees C for the film deposited at 5 W applied plasma power.