Process Optimization and Integration of Trimethylsilane-Deposited α-SiC:H and α-SiCO:H Dielectric Thin Films for Damascene Processing

Abstract

The semiconductor grade organosilicon gas trimethylsilane (Dow Corning Z3MS) can be used to deposit unique amorphous hydrogenated silicon carbide (α-SiC:H)-based alloy films that exhibit desirable properties such as chemical resistance, low stress, low permittivity, and low leakage. These film characteristics are ideal for applications in Cu-damascene interconnect technology. In this work, the results of a comprehensive study of Z3MS plasma enhanced chemical vapor deposition (PECVD) dielectric films are reported where all depositions were performed in commercial production PECVD equipment. Processing for α-SiC:H films deposited from Z3MS/He mixtures was optimized for deposition rate, uniformity, and permittivity. The processing parameters can be tuned for relative permittivity down to making α-SiC:H an attractive substitute for PECVD silicon oxide or silicon nitride. Using mixtures of Z3MS and precursors, α-SiCO:H films were deposited with very high deposition rates and film permittivity as low as These films have been applied in damascene technology. Physical properties and stability of blanket films were studied. Measurement of relative permittivity, leakage current, and breakdown voltage was performed on metal/dielectric/metal structures. Fourier transform infrared, X-ray photoelectron, and high-energy ion scattering spectrometry were used to determine bonding and film compositions. Integration issues related to deep ultraviolet lithography, dry etch, strip, and metallization are discussed. Optimized film processes were integrated into 0.18 μm Cu damascene interconnect process technology and the electrical results were compared to standard PECVD oxide. The results of these studies indicate that the device performance improvements inferred from the blanket film properties can be realized in fully integrated interconnect structures. © 2003 The Electrochemical Society. All rights reserved.