Semiconductor device and manufacturing method thereof

A manufacturing method of a semiconductor device, the method comprising:

• forming contact holes respectively reaching metal films on corresponding steps on a stepped end portion of a stack body in which metal films and first insulating films are alternately stacked on a semiconductor substrate;
• forming conducting films on the metal films exposed from the contact holes, respectively;
• forming a second insulting film on inner surfaces of the contact holes and top surfaces of the conducting films;
• forming a barrier metal film in the contact holes, the barrier metal film covering the second insulating film and covering the entire top surfaces of the conducting films along with the second insulating film;
• and
• forming contact portions in the contact holes, respectively, the contact portions being electrically connected to the conducting films via the barrier metal film.