| 摘要 |
PURPOSE:To shorten the term from the decision of ROM data to completion of an IC and to reduce the size of a cell by rewriting the ROM data in the step of forming a through hole. CONSTITUTION:The source electrode of an MOSFET which forms ROM cells A, B is connected to diffused layer wirings 3 of GND, and a gate electrode forms word lines 2a, 2b. When a contacting hole 4 is superposed on the metal 15 of the first layer and a through hole 15 is placed like the ROM cell A, a drain electrode 1 is connected to a bit line 8, when a word line 2a is selected, the potential of the line 8 is dropped to L, and the first output level is obtained. When the through hole is not placed on the metal 15 like the ROM cell B, the potential of the line 8 is maintained H even when the word line 2b is selected, thereby obtaining the second output level. |
