Patent ID: 6388910
Filing Date: 2002-05-14
Classification: G11C,H01L

Abstract:
A NOR type mask ROM comprising:a plurality of main bit lines formed in parallel with each other; a plurality of first sub-bit lines connected to the main bit lines through bit line contacts; a plurality of T-shaped second sub-bit lines each having a vertical arm formed in parallel with the main bit lines, and a horizontal arm formed in perpendicular with the vertical arm; a plurality of third sub-bit lines each formed in parallel with the main bit lines and between vertical arms of two neighboring second sub-bit lines; a plurality of word lines formed in perpendicular with the main bit lines; a plurality of main bank selection lines formed in parallel with the word lines for selecting a memory block; and a plurality of sub-bank selection lines formed within each memory block for selectively connecting neighboring second and third sub-bit lines so as to select a corresponding sub-bank.