Manufacturing method of semiconductor device

摘要

The reduction of length of a gate electrode is suppressed in the process of thinning it. A hard mask (5a) is thinned and used to etch a gate electrode material film (4) to form a gate electrode. At this time, a resist mask (10) having an opening (11) over an active region (1) is formed; the resist mask (10) covers at least both ends in the length direction of the hard mask (5a) and exposes in the opening (11) at least the entirety of the part of the hard mask (5a) which lies right above the active region (1). The hard mask (5a) is thinned by etching using the resist mask (10) as a mask and therefore the hard mask (5a) is thinned in the part over the active region (1) without being shortened in the length direction. As a result, the gate electrode formed by using the thinned hard mask (5a) is not shortened in length.