Semiconductor device manufacturing method

A semiconductor device manufacturing method of forming a trench and a via in a porous low dielectric constant film formed on a substrate as an interlayer insulating film, includes: embedding a polymer having a urea bond in pores of the porous low dielectric constant film by supplying a raw material for polymerization to the porous low dielectric constant film; forming the via by etching the porous low dielectric constant film; subsequently, embedding a protective filling material made of an organic substance in the via; subsequently, forming the trench by etching the porous low dielectric constant film; subsequently, removing the protective filling material; and after the forming a trench, removing the polymer from the pores of the porous low dielectric constant film by heating the substrate to depolymerize the polymer, wherein the embedding a polymer having a urea bond in pores is performed before the forming a trench.