Abstract: The present invention relates to a method of forming a barrier metal layer for a hot Al plug and its structure and more particularly to remarkably ameliorate the performance of a barrier metal layer preventing Al metal used as an interconnection layer from diffusing into a silicon substrate. A barrier metal layer according to the present invention is a stacked structure comprising a top layer of Tungsten (W) formed by a Chemical Vapor Deposition (CVD) method and a bottom layer of TiN. Then, a Al interconnection layer deposited at high temperature fills a plug and finishes a plug structure having advantages of low manufacturing cost and full prevention of Al diffusion.

Abstract: A method for forming a metal plug is provided. The method includes: a) forming a metal contact window in a substrate having an oxide layer; b) forming a barrier layer over a top surface of the oxide layer and a wall defining the metal contact window; c) forming a metal layer covering the barrier layer and filling up the metal contact window; d) removing a portion of the metal layer located above the barrier layer covering the top surface of the oxide layer by a chemical mechanical polishing method; and e) removing the barrier layer covering the top surface of the oxide layer by an etching method.