Semiconductor memory having sub-word line replacement

摘要

In a semiconductor memory apparatus having a row decoder classified by main word lines and word lines, the number of spare lines for a defect is increased without increasing the number of spare main word lines. The area of a redundancy circuit is minimized to improve the yield of chip. Normal and spare memory blocks each including a plurality of memory cells are each divided so that replacement may be effected without increasing the number of spare main word lines even when defective addresses associated with a plurality of normal main word lines take place.