Semiconductor device and method for fabricating the same

A semiconductor device, comprising:

• a first lower wiring and a second lower wiring spaced apart from each other by a first distance;
• a first upper wiring on the first lower wiring;
• and
• a via connecting the first lower wiring and the first upper wiring, the via including a sidewall having a first slope, and a second distance between the second lower wiring and the via measured at the first slope being greater than the first distance.

A method for fabricating a semiconductor device, the method comprising:

• forming a lower wiring;
• forming an interlayer insulating film on the lower wiring, such that the interlayer insulating film includes a first portion having a first density, and a second portion on the first portion and having a second density smaller than the first density, the first portion and the second portion including a same material;
• forming a first mask pattern on the interlayer insulating film;
• removing at least a part of the first portion of the interlayer insulating film and at least a part of the second portion of the interlayer insulating film, using the first mask pattern as an etching mask, such that a trench for exposing the lower wiring is formed;
• and
• forming a via in the trench,
• wherein, during removal of the at least part of the first portion of the interlayer insulating film and the at least part of the second portion of the interlayer insulating film, a first etch rate of the first portion of the interlayer insulating film is smaller than a second etch rate of the second portion of the interlayer insulating film.