Method of manufacturing a semiconductor device

摘要

In a damascene method, trenches in interlayer insulation 12 are filled with a barrier layer, a seed layer and a copper containing layer 17. The surface of the copper layer 17 is kept free of copper oxide by not exposing the device to an oxygen containing atmosphere. The oxide-free surface of the copper is subjected to a N2 or NH3 nitriding plasma treatment to form a copper nitride (CuN) layer 24. A silicon containing copper diffusion prevention layer 18 (e.g. SiN, SiON, SiC, SiCOH) is formed by plasma CVD. The copper nitride layer 24 suppresses diffusion of silicon into the copper layer 17 such that the thickness of the copper silicide layer is reduced. Interconnection resistance is thus reduced.