Masashi Komatsu

An Organic Low-k Film Deposited by Plasma-Enhanced Copolymerization

A plasma-enhanced copolymerization technology has been developed in which organic precursors are designed and synthesized to form polymerized films with low dielectric constants. In order to lower the dielectric constant, a tricyclodecane (TCD) group is introduced as an organic precursor molecule because TCD is a large aliphatic hydrocarbon group, which contributes to lowering the film density. The TCD precursors are liquid at room temperature and they have a sufficient saturated vapor pressure to be applicable to the vapor phase deposition. The optimized dielectric constant of the TCD polymer was less than 2.5. A solid 13 C nuclear magnetic resonance spectrum showed that the TCD moiety in the precursor was included in the polymer without changing the structure. The effect of the substrate temperature on the film structure was studied by analyzing Raman spectra. It was revealed that the dielectric constant was associated with sp 2 carbon content in the TCD-based polymer films.

Effect of Bridging Groups of Precursors on Modulus Improvement in Plasma-Enhanced Copolymerized Low-k Films

The mechanical strength of an organic silica low dielectric constant film was enhanced by introducing a reinforcement monomer into a matrix monomer under plasma polymerization deposition. The modulus improvement mechanism was investigated by using pyrolysis gas chromatography and mass spectrometry. Incorporation of a reinforcement monomer in the film matrix through copolymerization reactions was confirmed. Compositional analysis of the films showed that the extent of reinforcement was associated with the copolymerization ratio and the monomer content in the film. It is also found that the modulus enhancement depends on the content of three-dimensional aromatic bridged structure.