A semiconductor memory device is disclosed that provides replacement of defective main memory portions with operational redundant memory portions. The device includes fuse circuitry that comprises both nonvolatile and volatile memory portions. Because the fuse circuitry includes a volatile memory...http://www.google.com.tw/patents/US5828599?utm_source=gb-gplus-share專利 US5828599 - Memory with electrically erasable and programmable redundancy
