A method for forming a semiconductor device includes the steps of forming a flowable film made of an insulating material with flowability; forming a first concave portion in the flowable film through transfer of a convex portion of a pressing face of a pressing member by pressing the pressing member against the flowable film; forming a solidified film having the first concave portion by solidifying the flowable film through annealing at a first temperature with the pressing member pressed against the flowable film; forming a burnt film having the first concave portion by burning the solidified film through annealing at a second temperature higher than the first temperature; forming a second concave portion connected at least to the first concave portion in the burnt film by forming, on the burnt film, a mask having an opening for forming the second concave portion and etching the burnt film by using the mask; and forming a plug and a metal interconnect by filing the first concave portion and the second concave portion of the burnt film with a conductive film.