The formation of a SiOx interfacial layer on low-k SiOCH materials fabricated in ULSI application

The characterizations of SiOCH films using oxygen plasma treatment depends linearly on the O-2/CO flow rate ratio. According to the results of Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses, it was found that the carbon composition decreases with increasing O-2/CO flow rate ratio, because more carbon in the Si-O-C and Si-CH3 bonds on the film surface would be converted by oxygen radicals. It was believed that the oxygen plasma could oxidize the SiOCH films and form a SiOx interfacial capping layer without much porosity. Moreover, the result of FTIR analysis revealed that there was no water absorbed on the film. A SiO2-like capping layer formed at the SiOCH film by the O-2/CO flow rate ratio of 0.75 had nearly the same dielectric properties from the result of capacitance-voltage (C-V) measurement in our research. (C) 2008 Elsevier B.V. All rights reserved.