A simple planarization technology is proposed, using an organosiloxane which gives a thicker film than conventional spin-on-glass (SOG) film. The new SOG material, HSG2200 (Hitachi Chemical Company, HSG), exhibits far better planarizing capability than the conventional one. A drawback to this film has been crack generation when it is exposed to an oxygen plasma in a resist ashing reactor. A new pretreatment, which we have named reactive glass stabilization (RGS), has been developed. RGS is the exposure of the film to an energetic O2 plasma at low temperature using a parallel electrode sputtering reactor. The surface layer of the film is converted to an SiO2-like condensed state which prevents the oxygen plasma from reaching the inner unconverted layer and delays further reaction between the plasma and the organosiloxane film. Three-layered interlevel dielectric using the RGS-treated HSG film as a middle layer was used to planarize a two-metal level interconnection that had superior characteristics compared to those of conventional SOGs. The resistance increase of Al-2 lines on the HSG sandwich structure was merely 4% over 0.7 µm line and space, which is far less than that of 76% on the conventional SOG sandwich structure. MOS devices with a two-metal level interconnection exhibited good electric characteristics and no hot carrier degradation. © 1990, The Electrochemical Society, Inc. All rights reserved.
