| 摘要 |
PURPOSE:To reduce the area of an ROM cell by forming a through-hole between a first layer metal connected to a drain electrode for an MOSFET and the second layer metal of a bit line. CONSTITUTION:Source electrodes from the MOSFETs (A) and (B) forming the ROM cell are connected to a GND wiring 3, a gate electrode 2 constitutes a word line, the drain electrodes 1 are connected to the first layer metals 6, the bit lines 5a, 5b are constituted by the second layer metals, and the through-holes 14 are formed to the superposed sections of the first layer metals 6 and the second layer metals of the bit lines, thus lowering the potential of the drain- electrode bit line 5a of the ROM cell (A) to a low level. An effect through which the area of the cell is reduced is dispayed more than the case of a mask ROM being rewritten by the second layer metals because the mask ROM is rewritten by the through-holes. |
