Physical and Barrier Properties of Amorphous Silicon-Oxycarbide Deposited by PECVD from Octamethylcyclotetrasiloxane

This work investigates the thermal stability and physical and barrier properties for three species of amorphous silicon-oxycarbide (α-SiCO) dielectric barrier films, deposited by plasma-enhanced chemical vapor deposition (PECVD), to copper (Cu) diffusion using octamethylcyclotetrasiloxane precursor and helium (He) carrier gas with and without oxygen reaction gas. The α-SiCO dielectric barrier film deposited by PECVD without reaction gas exhibits a low k -value of 2.8, thermally stable at temperatures up to 550°C, excellent moisture resistance, and superb Cu barrier property until 400°C. With the addition of reaction gas during the dielectric deposition process, the dielectric constant of the α-SiCO dielectric barrier films increases with increasing flow rate of reaction gas. Increasing flow rate of reaction gas during the deposition of the α-SiCO dielectric barrier films also degrades the thermal stability and moisture resistance of the dielectric barrier films. Moreover, the addition of reaction gas also results in a degraded Cu barrier property of dielectric films.