X-ray absorption studies of high performance Low-k dielectric materials

The XAFS measurement of the MSQ type low-k dielectrics (LKD(TM)) was conducted to clarify the structure change with and without the EB cure. Furthermore, three different types of other MSQ films, the ladder structure, the random structure and the CVD film, have been investigated as references. We have determined Si-O-Si bond angle and Si-O(Si-C) bond length by fitting the Fourier transformed EXAFS spectra. The ladder structure and the random structure have Si-O-Si bond angle of 133 and 146, respectively. Si-O-Si bond angle of LKD(TM) film is among that of the ladder and the random structure, and the XANES spectrum of LKD(TM) film displays two broad features, corresponding to the mixture of both structures. In contrast, Si-O-Si angles of the EB cured LKD(TM) film and the CVD film resemble each other, and the XANES features of both films are almost identical with that of the random structure. We have confirmed that the EB cure process for LKD(TM) film makes drastic structure change from the mixture of ladder and random structure to the random network structure.