Semiconductor device and method of manufacturing the same

A method of manufacturing a semiconductor device, comprising the steps of:

• forming a first isolation groove defining a first element formation region and a second isolation groove defining a second element formation region to reach from a main surface of a semiconductor substrate to a first depth, and forming an opening reaching from said main surface of said semiconductor substrate positioned between said first isolation groove and said second isolation groove to said first depth;
• forming a first semiconductor element in said first element formation region;
• forming a second semiconductor element in said second element formation region;
• forming an insulating film so as to fill said first isolation groove, said second isolation groove, and said opening to form a first insulating isolation portion in said first isolation groove and form a second insulating isolation portion in said second isolation groove;
• successively performing processing on a portion of said insulating film buried in said opening and on said semiconductor substrate to form a contact opening passing through said insulating film to reach a second depth deeper than said first depth;
• and
• forming a conductor in said contact opening to form a substrate contact portion in which said conductor is in contact with said semiconductor substrate at a portion from said first depth to said second depth.