Low temperature plasma-assisted chemical vapor deposition of tantalum nitride from tantalum pentabromide for copper metallization W x N is a promising candidate as a barrier material for Cu metallization. In this work, we report the characterization of W x N films deposited by plasma enhanced chemical vapor deposition using WF 6 /N 2 /H 2 gas mixtures. The films are analyzed by Rutherford backscattering spectrometry, Auger electron spectroscopy, atomic force microscopy, x-ray diffraction, transmission electron microscopy, differential scanning calorimetry, and sheet resistance combined with thickness measurements. The diffusion barrier properties are studied by using Cu-gate metal-oxidesemiconductor capacitors and subjecting to either bias-temperature stress ͑BTS͒ of 2 MV/cm at 250°C or thermal anneal up to 700°C, and evaluated by capacitance-voltage measurement. It is found that the as-deposited films with W/N ratios from 2-19 have an ''amorphous-like'' nature.Study of the initial growth shows that the W x N films form by nucleation and grow through coalescence, and the films exhibit a granular structure. The transformation from the amorphous-like structure to crystalline phase͑s͒ depends on the film stoichiometry. For the W/Nϳ2 films, there are two transformations starting at 497 and 578°C ͑at a heating rate of 10°C/min͒, corresponding to the formation of the W 2 N phase and to the further growth of the phase together with the formation of a small amount of ␣-W, respectively. The corresponding activation energies are 2.20 and 2.98 eV. For the W/Nϳ3 films, there is only one transformation ͑to the W 2 Nϩ␣-W͒ starting at 601°C and with an activation energy of 2.94 eV. The resistivity is found to be insensitive to the film stoichiometry when the film has an amorphous-like nature, but shows a larger decrease for W richer films upon annealing at 500°C. Moreover, for W/Nϳ2 and 3 films, the resistivities are largely determined by the film thickness, from about 200 ⍀ cm for the 120 nm films to 310-350 ⍀ cm for the 10 nm films. BTS results reveal that 10 nm of the W/Nϳ3 barrier shows no sign of degradation at least up to 105 h. By contrast, it is found that the initial barrier degradation occurs by annealing at 600°C and above. This is probably due to the formation of ␣-W grains in the W x N barrier at these temperatures.

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The semiconductor grade organosilicon gas trimethylsilane ͑Dow Corning Z3MS͒ can be used to deposit unique amorphous hydrogenated silicon carbide ͑␣-SiC:H͒-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 ͑PECVD͒ dielectric films are reported where all depositions were performed in commercial production PECVD equipment. Processing for ␣-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 ϳ 4.2 making ␣-SiC:H an attractive substitute for PECVD silicon oxide or silicon nitride. Using mixtures of Z3MS and N 2 O precursors, ␣-SiCO:H films were deposited with very high deposition rates and film permittivity as low as ϳ 2.5. 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 m 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.

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