| 摘要 |
A method is presented for self-test and self-repair of a semiconductor memory device. A single built-in self-test (BIST) engine with an extended address range is used to test the entirety of memory (i.e., both redundant and accessible memory portions) as a single array, preferably using a checkerboard bit pattern. An embodiment of the method comprises two stages. In the first stage, faulty rows in each memory portion are identified and their addresses recorded. Known-bad rows in accessible memory are then replaced by known-good redundant rows, and the resulting repaired memory is retested in a second stage. During the second stage, repair of the accessible memory portion is verified, while defects among the redundant portion are ignored. Compared to existing methods, the new method is believed to simplify the interface between the BIST and the built-in self-repair (BISR) circuitry, reduce the overall size of test and repair circuitry, and provide improved test coverage.
|
