TEM/EELS analysis of ultra low-k inter-metal dielectric

As the scaling of transistors proceeds towards the deep sub-micron level, there is a need of replacement of intermetal dielectric (IMD) from SiO
₂
(k = 4.2) to a material with dielectric constant k <; 3. In this study, we choose porous SiCOH with dielectric constant k = 2.4 for the use as IMD layer. The quantitative analysis of the elements present in SiCOH has been performed by electron energy-loss spectroscopy (EELS) study. The short-range order in porous SiCOH has been investigated by the Selected Area Electron Diffraction (SAED). The local short-range ordering examined by SAED gave a clear idea about the nearest-neighbour distance between atoms. The nearest-neighbour distance for the case of porous SiCOH is around 1.6 Å and the ordering extends upto nearly 5 Å. The average density calculated by SAED is about 2.0 g/cm
³
.