US Patent 7534695 Method of manufacturing a semiconductor device

A semiconductor-device manufacturing method includes forming an element separating insulating film on a semiconductor substrate; forming a gate multilayer film for forming a gate electrode thereon; removing the gate multilayer film in an alignment mark forming area positioned on the element separating insulating film; forming a pattern of a first conductive film in the element forming area; forming an alignment mark of the first conductive film, used in photolithography, in the alignment mark forming area surrounded by the gate multilayer film; forming an inter-layer insulating film thereon; removing the inter-layer insulating film in the alignment mark forming area, so that it remains on the gate multilayer film around the alignment mark forming area; removing or thinning the element separating insulating film around the alignment mark; and forming a pattern of a second conductive film on the inter-layer insulating film by performing alignment of the photolithography by using the alignment mark.