Correlation Study on the Optical Properties of Low-dielectricSiOC(-H) Thin Films from a BTMSM/O2 Precursor Deposited by UsingPlasma Enhanced Chemical Vapor Deposition

Abstract

Dielectric SiOC(-H) thin films of low-k interlayer dielectric materials were fabricated by using plasma enhanced chemical vapor deposition (PECVD). The precursor with flow rates from 16 sccm to 60 sccm at a constant 60 sccm flow rate for ambient O2 gas was dissociated by using PECVD and formed a low-k SiOC(-H) thin film on a p-type Si substrate. The bonding groups of the SiOC(-H) thin film were identified by measuring the absorption spectrum. The complex coupled correlations over all bonding groups and over all microscopic bands in each bonding group were calculated by using a two-dimensional correlation analysis method that allowed a study of the low-k characteristics of the SiOC(-H) films related with the sensitivities of the SiOCH3, the Si-O-Si(C) and the Si-CH3 bonding groups and their sub bands for various precursor perturbations and annealing effects. The density variation of Si-O-Si(C) open-link and cage-link structure was strongly correlated with the low dielectric constants of 2.27 ± 0.14 for as-deposited SiOC(-H) thin films and 2.02 ± 0.20 for annealed SiOC(-H) thin films for various the precursor densities. The parametric change of the micro structures in each group depended on the BTMSM flow rate and yielded an understanding of the low dielectric characteristic of the SiOC(-H) thin film.