Low-dielectric-constant alpha-SiCOF film for ULSI interconnection preparedby PECVD with TEOS/C4F8/O-2

Amorphous SiCOF films with high carbon concentration are prepared by PECVD (plasma-enhanced CVD) with TEOS/C4F8/O-2. The dielectric constant of (alpha -SiCOF film is reduced to 2.6 and other electric properties are improved r emarkably. The moisture resistibility of the film is also improved. Through FTIR and XPS analyses, the chemical construction of alpha -SiCOF film is i nvestigated. The mechanism of improvements in electrical properties and sta bility in moisture is further discussed. It is found that the ionic polariz ation and orientational polarization decrease in (alpha -SiCOF films and co ntribute a lot to the reduction in dielectric constant. In addition, becaus e of the hydrophobicity of incorporated C-F bonds, the moisture resistibili ty of alpha -SiCOF film is improved.