| 摘要 |
<p>PURPOSE:To enable a glass mask to be decreased in manufacturing cost and shortened in turnaround time by a method wherein binary data to be set on an unused region are made correspondent to data not patterned on the glass mask out of the data programmed on the glass mask if there is the unused region in a memory cell. CONSTITUTION:A mask programmable ROM is composed of MOS transistors Tr1 and Tr2, a NAND gate NA1, an inverter IN, and NOR gates NOR1 and NOR2. When an E-type transistor forming a memory cell is made correspondent to '0', the transistor Tr1 is made to be of a D type, and when the E-type transistor forming a memory cell is made correspondent to '1', the transistor Tr2 is made to be of a D type. As mentioned above, it is determined that data outputted from a sense amplifier are transmitted to an output circuit as they are or inverted. Therefore, data on a glass mask correspondent to the unused region of a memory cell become unneeded. By this setup, a glass mask can be decreased in manufacturing cost and shortened in turnaround time.</p> |
