SEMICONDUCTOR MEMORY DEVICE AND REFRESH METHOD THEREOF

摘要

According to the present invention, a semiconductor memory device includes: a normal memory cell block including a plurality of normal memory cells; a redundancy memory cell block including a plurality of redundancy memory cells for replacing repair memory cells of the normal memory cells; a weak cell information storage unit configured to, in response to a refresh command, store information on weak memory cells included in the normal and redundancy memory cell blocks; and a refresh control circuit configured to control memory cells corresponding to a refresh address among the normal memory cells and the redundancy memory cells to be refreshed and to control weak memory cells to be refreshed based on information on at least one weak memory cell stored in the weak cell information storage unit, wherein the weak memory cells are additionally refreshed at least once more than other memory cells by the refresh control circuit during a refresh cycle of the normal memory cells.