COPPER GATE BY DUAL DAMASCENE METHOD AND INTERCONNECTION THEREOF

PROBLEM TO BE SOLVED: To provide a low-cost manufacturing technique of a metal gate wherein the metal gate and the interconnection thereof of a semiconductor device are formed in a single processing. SOLUTION: The manufacturing method of a semiconductor device includes a process for preparing its silicon substrate having thereon insulation regions, a process for forming an insulation layer and depositing a first barrier metal layer in its gate region of its active region, a process for depositing a gate place holder layer on the first barrier metal layer, a process for forming its gate stack by etching the gate place holder layer and the first barrier metal layer, a process for constructing sidewalls on the peripheries of its gate stack, a process for forming its source/drain regions in its active region, a process for so etching an oxide layer deposited on the structure of its source/drain regions, as to form a dual damascene trench extending to the level of the gate place holder layer and form vias for its source/ drain regions, a process for depositing a second barrier metal layer in the dual damascene trench and the vias, a process for removing the gate place holder layer, a process for depositing a copper in the dual damascene trench and in the vias, and a process for so removing all the excess portions of the copper and the second barrier metal layer that their levels coincide with the level of the finally deposited oxide layer.