Analysis of an extreme low-κ organosilicate dielectric film exposed to representative plasmas and to a restorative process

Abstract

Three representative plasma chemistries, consisting of an oxidizing plasma, a reducing plasma, and a fluorocarbon-based plasma, were investigated for their effect on a model extreme low k organosilicate dielectric film (κ=1.6). FTIR spectroscopy indicates the formation of nydroxyl groups in the films exposed to the oxidizing plasma chemistry and of amine groups in the reducing plasma chemistry. The absorption peaks of methyl group are reduced in the FTIR spectra of all three plasma-exposed films. The modulus of all exposed films increased as did the surface roughness. The dielectric constant of the film was adversely affected by all plasma exposures with the reducing plasma being the least detrimental. A portion of the dielectric constant is recovered by a post-plasma anneal. However, a silylation-anneal sequence is required to regain hydrophobicity. © 2004 Materials Research Society.