Abstract: A first insulating film is formed on an underlying substrate, the first insulating film being made of a first insulating material. A second insulating film is formed on the first insulating film, the second insulating film being made of a second insulating material different from the first insulating material. A trench is formed through the second and first insulating film, the trench reaching at least an intermediate depth of the first insulating film. A wiring layer made of a conductive material is deposited on the second insulating film, the wiring layer burying the trench. The wiring layer is polished to leave the wiring layer in the trench. The wiring layer and second insulating film are polished until the first insulating film is exposed. Irregularity such as dishing and erosion can be suppressed from being formed.

Abstract: A semiconductor device has: a semiconductor substrate; a number of semiconductor elements formed on the semiconductor substrate; a plurality of lower level wiring layers electrically connected to the semiconductor elements; a plurality of first insulating layers electrically separating the lower level wiring layers and having a first dielectric constant; a plurality of middle level wiring layers electrically connected to the lower level wiring layers; a plurality of second insulating layers electrically separating the middle level wiring layers and having a second dielectric constant larger than the first dielectric constant; a plurality of upper level wiring layers electrically connected to the middle level wiring layers; a plurality of third insulating layers electrically separating the upper level wiring layers and having a third dielectric constant larger than the second dielectric constant. A multilevel wiring structure is provided which has a high performance and a high reliability.