According to one embodiment, a method for manufacturing a semiconductor device includes: (a) supplying an adsorbing material over an insulating film, wherein the adsorbing material is selected from the group consisting of H2O, HF, NO, NO2, NF3, and combinations thereof; (b) supplying a Mo material over the insulating film; (c) supplying a reducing agent over the insulating film; and (d) repeating the steps (a) to (c).