The present invention relates to a method for fabricating a semiconductor device comprising: preparing a semiconductor substrate; forming an insulation pattern including a trench on the semiconductor substrate; forming a metal film covering the inner wall of the trench conformally on the insulation pattern; forming a protection film on the upper surface of the metal film conformally providing slurry having abrasive grain of negative electrode on the semiconductor substrate where the protection film is formed performing chemical and mechanical polishing process for the protection film and the metal film for the upper surface of the insulation pattern to be exposed using the slurry; and forming a metal pattern and a protection pattern on the trench with the chemical and mechanical polishing process.
