Arrangement and method for identifying and localizing faulty circuits of a memory module
First Claim
1. An arrangement for identifying and localizing faulty memory cells of a memory under test, comprising:
- (a) a test processor integrated on a memory module together with the memory under test;
(b) replacement rows and/or replacement columns of memory cells in the memory under test employable for repair of the memory under test;
(c) the test processor including;
means for generating test patterns for the memory under test during a test mode,means for evaluating resulting signals output by the memory under test in response to the test patterns to identify faulty memory cells, andmeans for storing an addresses of faulty memory cells identified by said means for evaluating;
(d) the test processor including means for producing a repair plan for the faulty memory cells at the addresses stored by said means for storing, said repair plan designating rows and/or columns of the memory under test having the faulty memory cells to be replaced by the replacement rows and/or replacement columns;
(e) a drive circuit for the replacement rows and/or replacement columns of memory cells including EPROM cells; and
(f) means for programming said EPROM cells of said drive circuit so that the replacement rows and/or replacement columns replace the rows and/or columns having the faulty memory cells.
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Accused Products
Abstract
The identification of a faulty memory cells of a memory module ensues with the assistance of a selt-test method for whose implementation a processor (TPZ) is co-integrated on the memory module. In test mode, the test processor generates test patterns for the memory cells of the memory under test, evaluates the result signals output by the memory cells as a result of the test patterns and stores the addresses of memory cells that were identified as being faulty. With the assistance of the addresses of the faulty memory cells, the test processor produces a repair plan on the basis whereof rows and clumns having faulty memory cells are replaced with the assistance of replacemnet rows and replacement columns.
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Citations
13 Claims
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1. An arrangement for identifying and localizing faulty memory cells of a memory under test, comprising:
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(a) a test processor integrated on a memory module together with the memory under test; (b) replacement rows and/or replacement columns of memory cells in the memory under test employable for repair of the memory under test; (c) the test processor including; means for generating test patterns for the memory under test during a test mode, means for evaluating resulting signals output by the memory under test in response to the test patterns to identify faulty memory cells, and means for storing an addresses of faulty memory cells identified by said means for evaluating; (d) the test processor including means for producing a repair plan for the faulty memory cells at the addresses stored by said means for storing, said repair plan designating rows and/or columns of the memory under test having the faulty memory cells to be replaced by the replacement rows and/or replacement columns; (e) a drive circuit for the replacement rows and/or replacement columns of memory cells including EPROM cells; and (f) means for programming said EPROM cells of said drive circuit so that the replacement rows and/or replacement columns replace the rows and/or columns having the faulty memory cells. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for identifying and localizing faulty memory cells of a memory to be tested, comprising the following steps:
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(a) at the beginning of a test procedure, bringing the memory to be tested arranged on a memory module with a test processor into an initial condition by said test processor; (b) in a test mode, generating test patterns for the memory to be tested using the test processor, evaluating resulting signals output by the memory to be tested in response to the test patterns to identify faulty memory cells and storing addresses of the faulty memory cells identified in said evaluating step; (c) the test processor producing a repair plan for the faulty memory cells using the addresses stored during said storing step, rows/columns having faulty memory cells being replaceable by replacement rows/replacement columns according to said repair plan; (d) the test processor determining whether a repair is still possible;
terminating the test given a negative result thereof and reporting the module as being irreparable given a negative result;
given a positive result, continuing steps (b) through (d) until the entire memory has been tested;(e) after the conclusion of the test, the test processor determining whether faulty memory cells have been found;
when no faulty memory cells have been found during said test, reporting the module as being fault-free;
when, by contrast, faulty memory cells have been found during said test, programming EPROM cells arranged in a drive circuit for the replacement rows/replacement columns according to the repair plan, so that the replacement row/replacement column replaces the row/column having the faulty memory cells. - View Dependent Claims (10, 11, 12, 13)
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Specification