Plasma Impacts to an O-SiC Low-k Barrier Film

Abstract

An oxygen-doped silicon carbide (O-SiC) barrier film with a dielectric constant of 3.3 was tested using a downstream ashing plasma tool. We investigated the interactions of three plasma chemistries, and plasmas, with the O-SiC films. The plasma damage to the films were evaluated and chemical structure changes were examined. While the plasma changed the O-SiC film into a -like film, the plasma caused minimum damage to the film, and material removal can be controlled within 5%. The infrared spectra indicate no noticeable chemical structure changes after the plasma exposures. Further, the electrical properties, including dielectric constant, leakage current, and dielectric breakdown voltage, were measured after the films were exposed to these plasmas. These electrical characteristics are preserved after the films were exposed to the plasma. The results indicate that the plasma ashing chemistry can be effectively applied to the O-SiC films without generating degradation of the key film characteristics. © 2004 The Electrochemical Society. All rights reserved.