SEMICONDUCTOR MEMORY AND ITS ADDRESS ALLOTTING METHOD

摘要

PROBLEM TO BE SOLVED: To obtain a semiconductor memory and its address allotting method that can effectively utilized a spare memory cell array for redundancy when a defect does not exist. SOLUTION: This device is characterized in that an address of a normal memory cell array 21 is previously allotted to a spare memory cell array 22 for redundancy. When a defect occurs in a normal cell region, its defective address is allotted to a memory cell for redundancy, and it is replaced with an address allotted to a memory cell for redundancy before the replacement. When a defect does not exist or it is very few even if it exists, read-out margin exists, since bit line capacity is small, and a spare memory cell array 22 for redundancy in which a consumption current is small in bit line restoring can be effectively utilized.