a method of manufacturing a semiconductor device which has the steps of : forming an insulated gate field effect transistor of a first conductivity type on a semiconductor substrate ,; forming a first insulating film over the semiconductor substrate , the first insulating film covering the insulated gate electrode ; forming a contact window through the first insulating film to at least one of the source / drain regions ; embedding a metal plug in the contact window ; forming a second insulating film having an oxygen blocking function on the first insulating film , the second insulating film covering the metal plug ; forming a capacitor lower electrode on the second insulating film ; forming a dielectric oxide film having a perovskite crystal structure on the lower electrode ; annealing the semiconductor substrate in an oxygen - containing atmosphere ; and forming a capacitor upper electrode on the dielectric oxide film . a semiconductor device can be realized which has capacitors with dielectric oxide films of a perovskite crystal structure having a high dielectric constant .