The invention relates to a semiconductor device and a manufacture method thereof, in which CMP is used, comprising steps of: (a) forming wirings above a semiconductor substrate; (b) after the step (a), depositing a first insulating film by high density plasma (HDP) chemical vapor deposition (CVD), the first insulating film burying the wirings; (c) after the step (b), depositing a second insulating film above the first insulating film by a deposition method different from HDP-CVD; and (d) after the step (c), planarizing the second insulating film by chemical mechanical polishing using abrasivecontaining cerium dioxide abrasive grains. Thus, the issue of film residues after polishing can be resolved for the large substrate, and wafer degree thickness distribution of interlayer insulating films can be depressed.