Sg. Lee et al., Low dielectric constant 3MS alpha-SiC : H as Cu diffusion barrier layer inCu dual damascene process, JPN J A P 1, 40(4B), 2001, pp. 2663-2668
The primary candidate for the barrier/etch stop layer in damascene process
is silicon nitride. However, silicon nitride has a high dielectric constant
. To reduce the effective dielectric constant in the copper damascene struc
ture, silicon carbide, which is prepared by plasma enhanced chemical vapor
deposition (PECVD) using 3 methyl silane source (Z3MS), is studied for the
dielectric copper diffusion barrier. The dielectric constant of PECVD alpha
-SiC:H is varied from 4.0 to 7.0 and the fourier transform infrared (FTIR)
spectra peak intensity ratio of Si-CH3 bond to Si-C is also examined. The
reduction in dielectric constant of alpha -SiC:H using 3MS gas seems to be
related to the decreased density upon incorporation of Si-CH3 groups. The v
alue of capacitance with alpha -SiC is 8-10% lower than that with PECVD SiN
. The leak-age current with alpha -SiC:H barrier is lower by 1 order of mag
nitude than that with PECVD SiN barrier.