Abstract: A wire forming method for a semiconductor device includes the steps of depositing an insulation material on a semiconductor substrate and patterning the insulation material to form a first insulation layer, forming a lower capping layer on the first insulation layer, etching the lower capping layer and the first insulation layer to form a first contact hole that exposes a first part of the semiconductor substrate, forming a wire layer over the capping layer and the first part of the semiconductor substrate, performing a chemical and mechanical polishing (CMP) process with respect to the wire layer and the lower capping layer to expose the first insulation layer, forming a second insulation layer over the wire layer and the first insulation layer, and etching the first and second insulation layers to form a second contact hole that exposes a second part of the semiconductor substrate.