Disclosed is a method for manufacturing a semiconductor device by employing a dual damascene process. After a first insulation film including a conductive pattern is formed on a substrate, at least one etch stop film and at least one insulation film are alternatively formed on the first insulation film. A via hole for a contact or a trench for a metal wiring is formed through the insulation film, and then the via hole or the trench is filled with a filling film including a water-soluble polymer. After a photoresist film is coated on the filling film, the photoresist film is patterned to form a photoresist pattern and to remove the filling film. The DOF and processing margin of the photolithography process for forming the photoresist pattern can be improved because the photoresist film can have greatly reduced thickness due to the filling film.