Fabrication method of semiconductor device containing n- and p-channel MOSFETs

Claim 1

A fabrication method of a semiconductor device having a CMOS structure, said method comprising the steps of: (a) selectively forming an isolation insulator film on a semiconductor substrate to define a first active region where a first MOSFET is formed and a second active region where a second MOSFET is formed; (b) forming a gate insulator film on said first active region and said second active region; (c) forming a first gate electrode and a second gate electrode on said gate insulator film, said first gate electrode being placed over said first active region and said second gate electrode being placed over said second active region; (d) forming a first patterned photoresist film over said substrate, said first photoresist film having a first window that exposes said first active region and a surrounding area of said first active region; (e) selectively implanting first dopant ions of a first conductivity type into said substrate using said first photoresist film as a mask to form a first well region of said second conductivity type in said substrate, said first dopant ions penetrating through said first gate electrode and said gate insulator film into said first active region and through said isolation insulator film into said surrounding area of said first active region; (f) selectively implanting second dopant ions of a second conductivity type into said substrate using said first photoresist film as a mask, to form a first pair of source/drain regions of said second conductivity type in said first well region, said second dopant ions penetrating through said first well region and not penetrating through said isolation insulator film; (g) removing said first resist film after said step (f); (h) forming a second patterned resist film over said substrate, said second resist film having a second window that exposes said second active region and a surrounding area of said second active region; (i) selectively implanting third dopant ions of said second conductivity type into said substrate using said second resist film as a mask to form a second well region of said second conductivity type in said substrate, said third dopant ions penetrating through said second gate electrode and said gate insulator film into said second active region and through said isolation insulator film into said surrounding area of said second active region; (j) selectively implanting fourth dopant ions of said first conductivity type into said second well region using said second resist film as a mask to form a second pair of source/drain regions of said first conductivity type in said second well region, said fourth dopant ions penetrating through said second gate electrode and said gate insulator film into said second well region and not penetrating through said isolation insulator film; (k) removing said second resist film after said step (j); (l) forming an interlayer insulator film to cover said first active region having said first pairs of source/drain regions and said second active region having said second pair of source/drain regions and said isolation insulator film; (m) forming first contact holes that penetrate said interlayer insulator film and said underlying gate insulator film over said first active region; (n) forming second contact holes that penetrate said interlayer insulator film and said interlying gate insulator film over said second active region; (o) forming a third contact hole that penetrates said interlayer insulator film and said underlying isolation insulator film over said first well region; (p) forming a fourth contact hole that penetrates said interlayer insulator film and said underlying isolation insulator film over said second well region; and (q) forming a patterned conductor film on said interlayer insulator film, said conductor film being contacted with said first pair of source/drain regions of said second conductivity type through said first contact holes, with said second pair of source/drain regions of said first conductivity type through said second contact holes, with said first well region through said third contact hole, and with said second well region through said fourth contact hole.