Patent ID: 6946385

Claim:
A production method of a semiconductor device comprising: (a) a step of forming a first insulating film and then forming a second insulating film on said first insulating film, said first insulating film functioning as an insulating film through which penetrate via holes reaching the lower layer wiring formed on the semiconductor substrate, said second insulating film functioning as an insulating film between the upper buried wirings; (b) a step of forming on the second insulating film a first mask forming layer; (c) a step of forming on the first mask forming layer a first resist mask having an inverted pattern of wiring trenches for the upper wiring; (d) a step of etching the first mask forming layer through the first resist mask, thereby forming in the first mask forming layer a concave part conforming to the inverted pattern of wiring trenches for the upper wiring, and then forming on the first mask forming layer a second mask forming layer, thereby filling the concave part with the second mask forming layer; (e) a step of selectively removing the second mask forming layer on the region in which the wiring trench is formed, such that the second mask forming layer remains in the concave part of the first mask forming layer, thereby forming the second mask having the wiring trench pattern; (f) a step of forming on the first and second mask forming layers a second resist mask having an opening pattern of the via holes; (g) a step of etching the second mask, the first mask forming layer, and the second insulating film through the second resist mask as an etching mask, thereby opening the via holes; (h) a step of etching the first mask forming layer through the second mask as an etching mask, thereby forming the wiring trench in the first mask forming layer, and then etching the first insulating film through the second insulating film as a mask, thereby completing the via holes; (i) a step of etching the second insulating film through at least either of the first mask and the second mask, thereby forming the wiring trench in the second insulating film; and (j) a step of removing the second mask.