STUDY OF LOW-K SIOC FILMS DEPOSITED VIA ATOMIC LAYER DEPOSITION

Abstract

The deposition of SiOC thin films via remote plasma atomic layer deposition (RPALD) was investigated. Octamethylcyclotetrasiloxane (OMCTS) and O2, Ar, H2 plasmas were respectively used as a precursor and reactants during the deposition process at 400 °C. Plasma and deposition temperatures had a significant effect on the physical and electrical characteristics of the films. When Ar and H2 plasma was respectively used during the deposition process, films exhibited low dielectric constants while incorporating carbon; however, O2 plasma yielded carbon free SiO2 films. Low dielectric constants resulted in low film densities and the presence of carbon within the films. When Ar and H2 plasma was used as the reactant gas, pores within the films with loose structures and Si-C bonds served to lower the dielectric constant. As a result, Ar and H2 plasma conditions exhibited low dielectric constants of 2.7 and 3.1 at 100 °C, respectively. Meanwhile, the presence of carbon and low film densities caused leakage paths within the films. The wet etch rates of films deposited in various plasmas was also measured in a solution of dilute HF. Films deposited under H2 plasma conditions exhibited the lowest etch rates due to possessing high film densities and carbon compositions. XPS supported analyses demonstrating the bonding characteristics of Si, C, O components.