Semiconductor device comprising a composite layer structure

摘要

A semiconductor device according to the present invention includes a line structure formed on a semiconductor substrate. The line structure includes: a conductor layer formed on the semiconductor substrate; a dielectric film formed on the conductor layer; and a conductor line formed on the dielectric film. The dielectric film includes: a first dielectric portion, at least part of the first dielectric portion being located between the lower surface of the conductor line and the upper surface of the conductor layer; and second and third dielectric portions laterally arranged to interpose the first dielectric portion therebetween. The dielectric constant of the first dielectric portion is different from at least one of the dielectric constants of the second and third dielectric portions.