METHOD FOR FORMING METAL GATE ELECTRODE

摘要

PURPOSE: A method for forming a metal gate electrode is provided to form a gate electrode of a predetermined size by using an uniform hard mask layer. CONSTITUTION: A method for forming a metal gate electrode comprises the following steps. A gate oxide layer(13), a doped polycrystal silicon layer(15), and a titanium silicide layer(17) are formed sequentially on a semiconductor substrate(11). A tungsten silicide layer(19) is formed on the titanium silicide layer. A hard mask layer is formed on the tungsten silicide layer. A photoresist pattern(25) is formed on an upper portion of the hard mask by performing an exposure process and a developing process. The hard mask layer is etched by using an etch gas containing fluorine. The tungsten silicide layer and the titanium silicide layer are etched by using the etch gas containing chlorine. The doped polycrystal silicon layer is etched by using the hard mask layer as a mask.