| 摘要 |
PURPOSE:To realize a mask ROM having the extremely high density of integration by forming a first wiring onto a semiconductor substrate, crossing a second wiring with the first wiring and forming a third wiring between the second wiring in wirings composed of the conductor films of three layers. CONSTITUTION:In the mask ROM, memory cells are formed at the intersections of first wirings F1-F3 and second wirings S1-S3, the intersections of the first wirings F1-F3 and third wirings T1-T3, the intersection of sections among the first wirings F1-F3 and the second wirings S1-S3 and the intersections of the sections among the first wirings F1-F3 and the third wirings T1-T3 respectively. These memory cells are arranged onto a semiconductor substrate 1 without clearance, and isolation regions for isolating the memory cells are unnecessitated, thus increasing areas capable of being used as memory cell forming regions, then realizing the mask ROM having the extremely high density of integration. |
