US Patent 7199420 Semiconductor device

A memory region including a capacitor element, a logic region including a logic circuit, and a boundary region located between the memory region and the logic region are provided on a silicon substrate. The memory region includes a plurality of memory transistors and memory transistor connection plugs. The boundary region includes a dummy contact plug in the same layer as the memory transistor connection plugs and logic transistor connection plugs. The upper face of the dummy contact plug is covered with a second insulating layer. An end portion of a capacitor layer and an upper electrode is located closer to an inner region of the memory region than the dummy contact plug is.