Semiconductor memory device with reduced chip area and improved redundancy efficency

摘要

A redundancy circuit embedded in the semiconductor memory device includes a sector selector and a bit line selector. The bit line selector repairs defective bit lines and the sector selector repairs defective global bit lines and selectively repairs defective bit lines. The sector selector includes a fixed address cell storage box for storing addresses of the defective bit lines and a flexible address cell storage box for storing addresses of the defective global bit lines. The circuit area is minimized since the coding unit corresponding to a sector address is not included in the bit line selector. The repair rate of defective bit lines is improved since the sector selector operates selectively as the bit line selector.