Semiconductor memory device comprising controllable threshould voltage dummy memory cells

Abstract

The present invention provides a semiconductor memory device capable of preventing a defect caused by falling of a word line and deterioration in patterning precision due to disturbance of the pitch of word lines at an end of a memory block. Plural dummy word lines are disposed at an end of a memory block and a word driver is mounted for the dummy word line to control the threshold voltage of a dummy memory cell formed below the dummy word line. Also at the time of operating a memory area for storing data from the outside, a bias is applied to the dummy word line. The invention can prevent a defect caused by falling of a word line and deterioration in patterning precision due to disturbance of the pitches of word lines at an end of a memory block, and realize high yield and reliable operation.