Process for fabricating tantalum nitride diffusion barrier for copper matallization

摘要

A process for fabricating a tantalum nitride diffusion barrier for the advanced copper metallization of semiconductor devices is disclosed. The process comprises the steps of first preparing a semiconductor device fabricated over the surface of a silicon substrate having a component with a fabricated contact opening. Before the formation of the copper contact by deposition, the process performs a tantalum nitride low- pressure chemical-vapor-deposition procedure that deposits a layer of tantalum nitride thin film over the surface of the device substrate. After the copper deposition, a photoresist layer is subsequently fabricated for patterning the deposited copper contact and tantalum nitride layers, whereby the deposited thin film of tantalum nitride is patterned to form the thin film as the metallization diffusion barrier for the semiconductor device. The tantalum nitride low-pressure chemical- vapor-deposition procedure includes depositing a layer of tantalum nitride utilizing a metal-organic precursor terbutylimido-tris- diethylamido tantalum (TBTDET) in a cold-wall low pressure reactor with a base pressure of about 10.sup.-5 torr. The source of the metal-organic precursor is vaporized at a temperature of about 40° to 50° C. The typical deposition pressure is about 20 mtorr. Tantalum nitride layer of low carbon content and low resistivity may thus be formed in the disclosed chemical-vapor-deposition procedure having effective capability against copper diffusion.