Formation Mechanism and Structural Characteristics of Low-Dielectric-Constant SiOC(-H) Films Deposited by Using Plasma-Enhanced Chemical-Vapor Deposition with DMDMS and O2 Precursors

SiOC(-H) films were deposited with and without ultraviolet irradiation on p-Si(100) substrate by using plasma-enhanced chemical-vapor deposition (PECVD) with dimethyldimethoxysilane (DMDMS) and oxygen precursors. The DMDMS/O2 flow rate ratio was varied from 10 to 100 % to investigate its effect on the properties of the films. Various species in the DMDMS/O2 plasma were identified using optical emission spectroscopy (OES). The deposition rate increased with increasing oxygen flow rate, and precursor molecules were dissociated due to the activation of oxygen radicals. The chemical structure was characterized by using Fourier transform infrared spectroscopy (FTIR) in the absorbance mode. These measurements show that more C and H were incorporated into the O-Si-O network. As more carbon atoms were incorporated into the SiOC(-H) film with increasing DMDMS flow rate ratio, the dielectric constant was reduced due to introduction of more Si-C related bonds in the film. KCI Citation Count: 11