Structure Characterization of Porous Interlevel Dielectric Film

The structure characterization of nanoporous interlevel dielectric (ILD) thin films is challenging because of the small sample volumes and nanometer dimensions of the pores. In this chapter, we review characterization methods for porous ILD materials using X-ray and neutron radiation sources. These methods include X-ray reflectivity (XR), small angle X-ray scattering (SAXS), small angle neutron scattering (SANS), and X-ray Porosimetry (XRP). XRP, in particular, shows promise as a general laboratory characterization method that provides detailed structural information of nanoporous ILD thin films. In XRP, changes in the critical angle for total X-ray reflectance provide a sensitive measure of mass uptake of a condensate into the film.Current porosimetry absorption/desorption models can then be used to determine structure parameters such as porosity and the distribution of pore sizes. Further, XRP data can be used to determine pore structure as a function of depth in non-uniform thin films. Detailed comparisons of XRP results with those from SANS are shown and discussed