Semiconductor memory and method of storing configuration data
View Patent ↗Redundantly repaired semiconductor memory and method in which the configuration data for the memory is stored in an area of the main memory array which is known to be free of bad bits, along with a signature code which serves as a pointer and verifies the validity of the configuration data. In one disclosed embodiment, the data is stored in a configuration memory which is divided into a plurality of areas of equal size and known starting addresses. The number of areas is greater than the number of permitted repairs, and the areas which do not contain defects are available for storing configuration data including device settings, repair information, and the like.
1. A semiconductor memory with redundancy repair, comprising a main memory array, configuration data stored in an area of the array which is known to be unrepaired, and a signature code that verifies the validity of the configuration data and is stored in the unrepaired area as a pointer to the configuration data.
2. The semiconductor memory of claim 1 wherein the signature code is stored at a known address.
3. The semiconductor memory of claim 1 wherein the area in which the configuration data is stored is part of a configuration page having a plurality of areas which are known to be unrepaired and which can be utilized to store repair information during testing of the memory, the number of areas in the configuration page being greater than the number of repairs permitted to be made in the memory array.
4. A semiconductor memory with redundancy repair, comprising a main memory array, a configuration page divided into a plurality of storage areas, data for configuration of the memory stored in one of the storage areas which has been tested and found to be free of bad bits, and a signature code stored with the configuration data in the area which is free of bad bits.
5. The semiconductor memory of claim 4 wherein the number of storage areas in the configuration page is greater than the number of repairs permitted to be made in the memory array.
6. The semiconductor memory of claim 4 wherein each of the storage areas starts at a known address of the memory array.
7. A method of storing configuration data for a semiconductor memory in which defective areas of a main memory array are repaired redundantly, comprising the steps of: identifying an area of the main memory array which has not been repaired, storing configuration data for the memory in the unrepaired area, and storing a signature code that verifies the validity of the configuration data in the unrepaired area as a pointer to the configuration data.
8. The method of claim 7 wherein the signature code is stored at a known address in the memory array.
9. A method of storing configuration data for a semiconductor memory in which defective areas of a main memory array are repaired redundantly, comprising the steps of: setting up a configuration page in the main memory array, with the configuration page being divided into a plurality of areas of equal size and known starting addresses, testing the areas in the configuration page to identify an area which is free of bad bits, storing configuration data in the area which is free of bad bits, and storing a signature code in the area of the configuration rage with the configuration data.
10. The method of claim 9 including the step of erasing the configuration page before storing the configuration data.
11. A method of configuring a semiconductor memory in which defective areas of a main memory array are repaired redundantly, the steps of: setting up a configuration page in the main memory array, with the configuration page being divided into a plurality of areas with known starting addresses, storing configuration data in one of the areas of the configuration page which is known to be free of bad bits, storing a signature code in the area of the configuration page with the configuration data, addressing the areas of the configuration page until the signature code is found, and reading the configuration data from the area where the signature code is found.
12. The method of claim 11 wherein the areas of the configuration page are of equal size.
13. The method of claim 11 including the step of storing repair information as repairs are made.
14. A configuration memory for a semiconductor memory having a main memory array which can be redundantly repaired, comprising: a configuration page divided into a plurality of storage areas of equal size and known starting addresses, configuration data stored in one of the areas which is known to be free of bad bits, and a signature code stored in the area with the configuration data for verifying the validity of the configuration data.
15. The configuration memory of claim 14 wherein the configuration page is an integral part of the main memory array.