Hardware and software programmable fuses for memory repair
The present invention relates to a system and method for increasing the manufacturing yield of a plurality of memory cells used in cell arrays. A programmable fuse, having both hardware and software elements, is used with the plurality of memory cells to indicate that at least one memory cell is unusable and should be shifted out of operation. The software programmable element includes a programmable register adapted to shift in an appropriate value indicating that at least one of the memory cells is flawed. The hardware element includes a fuse gated with the programmable register. Shifting is indicated either by software programmable fuse or hard fuse. Soft fuse registers may be chained together forming a shift register.
1. A programmable device used with a part and adapted to increase manufacturing yield of the part, the device comprising:
at least hardware and software modes;
said hardware mode comprising at least a hardware programmable element adapted to indicate that a portion of the part should be shifted out of operation; and
said software mode comprising at least a software programmable element adapted to shift in an appropriate value indicating that said portion of the part should be shifted out of operation, wherein said hardware and software modes act autonomously.
2. The device according to claim 1 , wherein said hardware programmable element is adapted to be used with a laser device.
3. The device according to claim 2 , wherein said laser device and said hardware programmable element are used to indicate that at least one memory cell is unusable.
4. The device according to claim 1 , wherein said software programmable element is adapted to be used with an electric pulse.
5. The device according to claim 4 , wherein said electric pulse and said software programmable element are used to indicate that at least one memory cell is unusable.
6. The device according to claim 1 , wherein said software programmable element comprises a shift register.
7. The device according to claim 6 , wherein said shift register is adapted to shift in said appropriate value.
8. The device according to claim 1 , wherein said hardware programmable element is used to indicate that at least one memory cell is unusable.
9. The device according to claim 1 , wherein said software mode comprises a programmable register, and wherein said programmable register comprises a shift clock interface that is adapted to shift in said appropriate value to indicate that at least one faulty memory cell within an array of memory cells should be shifted out of operation.
10. The device according to claim 9 , wherein the programmable register is a software programmable register.
11. The device according to claim 9 , wherein said programmable register comprises a data input interface that is adapted to shift in said appropriate value.
12. The device according to claim 9 , wherein said programmable register is reset upon power up.
13. The device according to claim 12 , wherein, when said programmable register is reset, a fuse input pin is tied to a particular value and said a shift clock is tied to a system clock.
14. The device according to claim 9 , wherein said programmable register is reset when said software mode is not used.
15. The device according to claim 9 , wherein said programmable register is reset after a predetermined number of cycles has passed.
16. The device according to claim 15 , wherein said predetermined number of cycles is equal to a number of fuses.
17. The device according to claim 1 , wherein said software programmable element is used to indicate that at least one memory cell of a plurality of memory cells is unusable.
18. The device according to claim 1 , wherein said portion of the part comprises a faulty portion of said part.
19. The device according to claim 1 , wherein said software programmable element is adapted to be connected to another software programmable element, and wherein said another software programmable element shifts in another appropriate value representing another portion of said part that should be shifted out of operation.
20. The device according to claim 19 , wherein said another appropriate value is shifted in through a daisy chain configuration of said software programmable element and said another software programmable element.
21. The device according to claim 1 , wherein said hardware programmable element or said software programmable element comprises a programmable register that is adapted to indicate that at least one memory cell in a memory cell array is flawed.
22. The device according to claim 21 , wherein a fuse is coupled to said programmable register.
23. The device according to claim 22 , wherein said fuse and said programmable register are adapted to be used in a row redundancy scheme or a column redundancy scheme in a memory cell array.
24. The device according to claim 1 , wherein one of said hardware mode and said software mode indicates that at least one memory cell in a memory cell array is faulty.
25. The device according to claim 1 , wherein said part comprises a memory cell array, and wherein said portion comprises one or more memory cells of said memory cell array.
26. The device according to claim 25 , wherein said one or more memory cells are faulty.
27. The device according to claim 1 , wherein said device is a programmable fuse.
28. The device according to claim 1 , wherein said device is within said part.