A semiconductor device manufacturing method including forming a dummy capacitor in a fuse region to avoid a step height between plate electrodes in a cell region and in a fuse region, is disclosed herein. The method can be used so that only an insulating film at a target thickness may remain on an upper part of the plate electrode in the fuse region during an etching process for forming a fuse open region, and a fuse failure due to laser blowing can be prevented.