System and method for repairing a memory

• US 7,415,641 B1
• Filed: 11/05/2003
• Issued: 08/19/2008
• Est. Priority Date: 11/05/2003
• Status: Active Grant

• Current Assignee: Synopsys Incorporated
• Original Assignee: Virage Logic Corporation (Synopsys Incorporated)
• Inventors: Zorian, Yervant, Behera, Niranjan, Prickett, Bruce L. Jr.
• Primary Examiner(s): Britt; Cynthia
• Application Number:
  US10/702,014
• Time in Patent Office: 1,749 Days
• Field of Search: 714/710, 714/711, 714/719
• US Class Current: 714/711
• CPC Class Codes: G11C 29/16 using microprogrammed units, e.g. state machines
• CPC Class Codes: G11C 29/44 Indication or identification of errors, e.g. for repair
• CPC Class Codes: G11C 29/4401 for self repair
• CPC Class Codes: G11C 29/848 by adjacent switching

Abstract

A method and system for repairing a memory. A test and repair wrapper is operable to be integrated with input/output (I/O) circuitry of a memory instance to form a wrapper I/O (WIO) block that is operable to receive test and repair information from a built-in self-test and repair (BISTR) processor. Logic circuitry associated with the WIO block is operable generate a current error signal that is used locally by the BISTR processor for providing a repair enable control signal in order to repair a faulty memory portion using a redundant memory portion without having to access a post-processing environment for repair signature generation.

Claims

1. A method of repairing a memory instance having a plurality (N) of main array column (MAC) portions and a redundancy array column (RAC) portion, wherein each of said MAC portions and said RAC portion is associated with a sense amplifier and write driver (SAWD) circuit block for operably coupling with one of N input/output (I/O) blocks provided for said memory instance, comprising:

detecting that one of said MAC portions is faulty;

decoupling said faulty MAC portion'"'"'s SAWD circuit block from an I/O block associated therewith and shifting said faulty MAC portion'"'"'s I/O block to a SAWD circuit block associated with a MAC portion immediately next to said faulty MAC portion on a selected side thereof; and

successively shifting coupling relationships between SAWD circuit blocks and I/O blocks for each MAC portion disposed on said selected side of said faulty MAC portion until an I/O block associated with a MAC portion that is immediately next to said RAC portion is shifted to said RAC portion'"'"'s SAWD circuit block.

2. The method of repairing a memory instance as set forth in claim 1, wherein said operation of detecting that one of said MAC portions is faulty is performed responsive to test information provided by a built-in self-test and repair (BISTR) processor associated with said memory instance.

3. The method of repairing a memory instance as set forth in claim 2, wherein said test information is scanned into a test and repair logic wrapper integrated with said memory instance for performing testing operations with respect to said memory instance.

4. The method of repairing a memory instance as set forth in claim 3, wherein a current error signal is generated by said test and repair logic wrapper responsive to said detecting operation.

5. The method of repairing a memory instance as set forth in claim 4, wherein a repair enable signal is generated by said BISTR processor responsive to said current error signal, said repair enable signal operating to control said decoupling and shifting operations with respect to said faulty MAC portion'"'"'s I/O circuit block.

6. The method of repairing a memory instance as set forth in claim 4, wherein said operation of successively shifting said coupling relationships between SAWD circuit blocks and I/O blocks is mediated by a RIPPLE control signal generated upon detecting that one of said MAC portions is faulty.

7. The method of repairing a memory instance as set forth in claim 1, wherein each I/O block is operatively connected to a SAWD circuit block through a respective multiplexer block.

8. A system for repairing a memory instance having a plurality (N) of main array column (MAC) portions and a redundancy array column (RAC) portion, wherein each of said MAC portions and said RAC portion is associated with a sense amplifier and write driver (SAWD) circuit block for operably coupling with one of N input/output (I/O) blocks provided for said memory instance, comprising:

circuitry for detecting that one of said MAC portions is faulty;

circuitry for decoupling said faulty MAC portion'"'"'s SAWD circuit block from an I/O block associated therewith and for shifting said faulty MAC portion'"'"'s I/O block to a SAWD circuit block associated with a MAC portion immediately next to said faulty MAC portion on a selected side thereof; and

circuitry for successively shifting coupling relationships between SAWD circuit blocks and I/O blocks for each MAC portion disposed on said selected side of said faulty MAC portion until an I/O block associated with a MAC portion that is immediately next to said RAC portion is shifted to said RAC portion'"'"'s SAWD circuit block.

9. The system for repairing a memory instance as set forth in claim 8, wherein said circuitry for decoupling and shifting said faulty MAC portion'"'"'s I/O block is comprised of a multiplexer block operable responsive to a REPAIR signal.

10. The system for repairing a memory instance as set forth in claim 9, wherein said REPAIR signal is generated responsive to a repair enable signal provided by a built-in self-test and repair (BISTR) processor associated with said memory instance and a RIPPLE signal generated at least in part by said circuitry for successively shifting coupling relationships between said SAWD circuit blocks and I/O blocks for each MAC portion disposed on said selected one side of said faulty MAC portion.

11. The system for repairing a memory instance as set forth in claim 8, wherein said circuitry for detecting that one of said MAC portions is faulty comprises read compare logic operable to compare data output from said MAC portion with a test compare data value.

12. The system for repairing a memory instance as set forth in claim 11, wherein said test compare data value is provided by a test and repair wrapper integrated with said memory instance for performing testing operations with respect to said memory instance.

13. The system for repairing a memory instance as set forth in claim 11, wherein a current error signal is generated by said test and repair logic wrapper when one of said MAC portions is faulty.

14. The system for repairing a memory instance as set forth in claim 11, wherein said read compare logic comprises an exclusive-OR circuit.