METHOD OF FABRICATING A METAL PLUG OF A SEMICONDUCTOR DEVICE USING A NOVEL TIN BARRIER LAYER

A method of fabricating a metal plug comprises steps of providing a substrate and forming a dielectric layer on the substrate with an opening to expose part of the substrate. The method further comprises steps of forming a metal layer on the dielectric layer, forming a first barrier layer by chemical vapor deposition (CVD) to provide a better step coverage, and forming a second barrier layer by physical vapor deposition (PVD) to make the barrier layer harder and less water absorptive. A metal layer is then formed on the second barrier layer and is removed by etching back to form the metal plug.