Patent ID: 6194767
Filing Date: 2001-02-27
Classification: G11C,H01L

Abstract:
In an X-shaped ROM semiconductor memory device of the type including:a plurality of elongated polysilicon word lines arranged in vertically spaced rows,a plurality of horizontally spaced cell transistors electrically connected to the polysilicon word lines,a plurality of elongated metal bit lines and elongated selectable ground lines alternately arranged in horizontally spaced columns between the cell transistors,contact regions for connecting adjacent cell transistors, anda ground terminal;the improvement characterized by said selectable ground lines including:groups of adjacent odd and even polysilicon selectable ground lines,a first and a second metal selectable ground line on opposite sides of each group of polysilicon selectable ground lines,a first polysilicon interconnect line for interconnecting the odd polysilicon selectable ground lines of each group of polysilicon selectable ground lines to the first metal selectable ground line,a second polysilicon interconnect line for interconnecting the even polysilicon selectable ground lines of each group of polysilicon selectable ground lines to the second metal selectable ground line, andfirst and second driving transistors for connecting the first and second metal selectable ground lines, respectively, to the ground terminal.