Testing apparatus for redundant memory
First Claim
1. In an apparatus for testing a redundant memory including means for applying a test pattern to a memory under test which has a matrix of storage cells having X and Y addresses, means for determining failures in the data stored in the storage cells of said memory on the basis of test results obtained by comparing outputs from said memory under test with expected values, and means for remedying said failures along selected redundant lines in the X and/or Y directions of said matrix of storage cells, the improvement comprising:
- (a) a compressed data matrix storage device for storing as compressed data only the data relating to failures determined from the test results of said failure determining means;
(b) an address conversion unit which converts the X and Y addresses of said failures detected by said failure determining means into addresses of said compressed data matrix storage device and controls the storing of failure data in said compressed data matrix storage device;
(c) an auxiliary processing unit which judges whether remedy of the failures is possible on the basis of the data of the test results stored in said compressed data matrix storage device and for controlling said remedying means when remedy of the failures is not possible;
(d) means for selecting said redundant lines by analyzing the data in said compressed data matrix storage device and for supplying the identify of said redundant lines to said remedying means; and
(e) means for supplying the data in said compressed data matrix storage device to said remedying means.
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Accused Products
Abstract
Only that data which relates to detected failures of data stored in a memory under test is stored in a compressed data matrix of a small capacity which is determined by a predetermined number of redundant lines to be selected for remedy of the failures, and the selection of the redundant lines is effected during the execution of a test on the memory. Analysis leading to redundant line selection is effected on the data stored in this compressed matrix.
52 Citations
12 Claims
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1. In an apparatus for testing a redundant memory including means for applying a test pattern to a memory under test which has a matrix of storage cells having X and Y addresses, means for determining failures in the data stored in the storage cells of said memory on the basis of test results obtained by comparing outputs from said memory under test with expected values, and means for remedying said failures along selected redundant lines in the X and/or Y directions of said matrix of storage cells, the improvement comprising:
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(a) a compressed data matrix storage device for storing as compressed data only the data relating to failures determined from the test results of said failure determining means; (b) an address conversion unit which converts the X and Y addresses of said failures detected by said failure determining means into addresses of said compressed data matrix storage device and controls the storing of failure data in said compressed data matrix storage device; (c) an auxiliary processing unit which judges whether remedy of the failures is possible on the basis of the data of the test results stored in said compressed data matrix storage device and for controlling said remedying means when remedy of the failures is not possible; (d) means for selecting said redundant lines by analyzing the data in said compressed data matrix storage device and for supplying the identify of said redundant lines to said remedying means; and (e) means for supplying the data in said compressed data matrix storage device to said remedying means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification