Measurement of desorbed products during organic polymer thin film etching by plasma beam irradiation

Abstract

The authors investigated the etching characteristics of three kinds of methacrylate polymer films, which have the same main chain but with different side chains, using a plasma beam irradiation apparatus. The polymers are polytbutylmethacrylate, polybenzylmethacrylate, and polycyclohexylmethacrylate. The major desorbed products during nitrogen plasma beam etching were found to be HCN and C2N2 for all methacrylate polymer films. The desorbed products originating from the polymer structure, namely, the main chain and the side chain, were hardly observed. The energy distributions of desorbed products were mainly composed of Maxwell-Boltzmann distribution with a small component of collision cascade distribution for all three polymers and were slightly dependent on the ion energy. It is concluded that chemical sputtering, which can be defined as the production of weakly bound species by ion bombardment, followed by thermal desorption, is the significant ion induced mechanism of organic polymer etching.

Hydrogen effects in hydrofluorocarbon plasma etching of silicon nitride: Beam study with CF+, CF2+, CHF2+, and CH2F+ ions

“…Based on the above-given observations, we conjecture the etching reaction mechanism of Si 3 N 4 by hydrofluorocarbon ions. First, when a bare surface of Si 3 N 4 is exposed to incident hydrofluorocarbon ion beams, the hydrogen of the incident ion beam reacts with nitrogen of Si 3 N 4 as well as accumulated carbon on the surface and forms volatile products such as hydrogen cyanide (HCN), [12][13][14] facilitating etching of Si 3 N 4 caused by reactions between substrate silicon and fluorine of incident ions. The reactions of hydrogen with nitrogen and/or carbon are likely to suppress the deposition of fluorinated carbon and further enhance Si 3 N 4 etching reactions.…”

Atomic-Scale Analyses of Non-Equilibrium Surface Reactions During Plasma Processing

“…Organic polymers have been extensively studied as candidates for low dielectric-constant insulating materials in semiconductor chips. In actual etching processes in semiconductor manufacturing, organic polymers are usually etched with hydrogen/nitrogen plasmas [6,7]. Discussion on MD simulations of such etching processes is found in Ref.…”