A method of forming a metal interconnection of semiconductor device is provided. The method includes forming a low-k dielectric layer including an opening; forming a barrier metal pattern conformally covering a bottom surface and an inner sidewall of the opening; forming a metal pattern exposing a part of the inner sidewall of the barrier metal pattern in the opening; forming a metal capping layer on the top surfaces of the metal pattern and the low-k dielectric layer using a selective chemical vapor deposition process, wherein the thickness of the metal capping layer on the metal pattern is greater than the thickness of the metal capping layer on the low-k dielectric layer; and forming a metal capping pattern covering the top surface of the metal pattern by planarizing the metal capping layer down to the top surface of the low-k dielectric layer.