In a semiconductor device having a repetitive pattern area in which a unitary wiring pattern is repeatedly arranged and covered with a multilayer insulator film composed of a silicon oxide film and a TEOSBPSG film, dummy conductors formed of the same layer as that of conductors of the wiring pattern are formed in an area adjacent to an edge zone of the repetitive pattern area. Thus, the outermost conductor positioned at the edge of the repetitive pattern area is no longer the outermost patterned conductor in an extended repetitive pattern area including the dummy conductors. Thus, the stress which acts on the outermost conductor of the repetitive pattern area because of the shrinkage of the silicon oxide film caused for the difference in thermal shrinkage coefficient between the silicon oxide film and the TEOSBPSG film, is relaxed, so that the shifting of the outermost conductor is prevented, and therefore, a short-circuiting caused by shifting of the outermost conductor is also prevented.