Abstract: A method provides an on-chip repair technique to fix defective row or I/O memory lines in an ASIC memory array with redundancy row or I/O memory lines. The method employs progressive urgency and dynamic repair schemes to optimize the allotted time for repairing defective row and I/O memory lines. Progressive urgency scheme increases the need to repair relative to the available redundancy row or I/O memory lines over the entire repairing time. Dynamic repair executes a mandatory-row or a mandatory-I/O repair as defective row or I/O memory lines are detected. In addition, a recurrence error reroutes the address location of a redundancy memory line to another address location of another redundancy memory line in the event that such redundancy memory line itself is defective, and thus requires further repair.

Abstract: A built-in self-repair system includes an on-chip clock generator for triggering the repairing process to repair defective memory lines or blocks in a memory array of an ASIC chip. The on-chip clock generator enables the self-repair process to start at the power up of a computer system without a need for an external test-triggering signal. The system includes a built-in self-test circuit that tests for a defective row memory line or a defective I/O memory block. The system further includes a fault-latching-and repair-execution circuit that repairs a row memory line or an I/O memory block. Repairing an IO memory block effectively repairs faults that occur between any two adjacent column shorts within an IO memory block. The preferred repairing scheme adopts a 15N diagnosis to achieve high fault correction so that a large percentage of defective memory cells can be replaced by redundant row memory lines or redundant I/O memory blocks.