| 摘要 |
PURPOSE: A mask ROM(Read Only Memory) is provided to improve the resolution that defines a pattern by freely adjusting a design size of a bit line. CONSTITUTION: A plurality of memory cell strings(21-28) are connected to a bit line. A memory cell string selection line receives three(N) selection signals in order to select a predetermined memory cell string among the memory cell strings(21-28). The memory cell string selection line is selected so that eight(2¬n) memory cell strings are connected to the bit line. A common source terminal connects the memory cell strings(21-28) in common. The memory cell string selection line is comprised of four enhancement mode NMOS(N-type Metal Oxide Semiconductor) transistors(32) and four depletion mode PMOS(P-type Metal Oxide Semiconductor) transistors(31). The memory cell string selection line is comprised of four depletion mode NMOS transistors and four enhancement mode PMOS transistors.
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