Effect of Bias-Voltage in H2/N2 Plasma Treatment on Porous Low Dielectric Constant Materials

Tuesday, May 13, 2014
Grand Foyer, Lobby Level (Hilton Orlando Bonnet Creek)
Y. L. Cheng, J. F. Huang, T. C. Bo, B. H. Lin, and C. M. Chen (National Chi-Nan University)
Porous low-dielectric constant (low-k) materials are needed for advanced technologies to improve signal propagation. Plasma treatments in interconnection fabrication have been considered to be critical steps to impact the low-k films’ properties. In this study, the degradation of the porous low-k films by plasma exposure using several kinds of treatment conditions was investigated in this study. The increase of the dielectric constant and the degradation of the porous low-k film reliability were found to be related to the decreased amount of Si-CH3 bonds and the absorbed amount of H2O or OH groups in the film. Pure H2 gas plasma treatment extracts more CH3 group from the porous low-k film and forms a larger amount of H2O or OH groups. Although N2 gas plasma treatment can suppress H2O or OH group formation, the increase of the dielectric constant is higher due to the formation of Si-N or C-N bonds. The plasma treatment using a mixture gas of H2 and N2 can obtain a balance result in the dielectric constant increase and absorbed moisture uptake. Furthermore, introducing an increasing bias-voltage on the sample electrode during H2/N2 Plasma treatment can effectively suppress the degradation of the porous low-k films.