SPEEDING UP DEFECT DIAGNOSIS TECHNIQUES
First Claim
1. A method of diagnosing defects in an electronic circuit, the method comprising:
- determining a set of one or more fault candidates for the electronic circuit for a set of failing test patterns by using a fault dictionary that describes responses of one or more modeled faults to the failing test patterns;
simulating one or more fault candidates of the determined set using passing test patterns, failing test patterns, or both failing and passing test patterns; and
storing the one or more fault candidates and results of the simulating one or more fault candidates on one or more computer-readable media.
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Abstract
Fault diagnosis techniques (e.g., effect-cause diagnosis techniques) can be speeded up by, for example, using a relatively small dictionary. Examples described herein exhibit a speed up of effect-cause diagnosis by up to about 160 times. The technologies can be used to diagnose defects using compacted fail data produced by test response compactors. A dictionary of small size can be used to reduce the size of a fault candidate list and also to facilitate procedures to select a subset of passing patterns for simulation. Critical path tracing can be used to handle failing patterns with a larger number of failing bits, and a pre-computed small dictionary can be used to quickly find the initial candidates for failing patterns with a smaller number of failing bits. Also described herein are exemplary techniques for selecting passing patterns for fault simulation to identify faults in an electronic circuit.
43 Citations
44 Claims
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1. A method of diagnosing defects in an electronic circuit, the method comprising:
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determining a set of one or more fault candidates for the electronic circuit for a set of failing test patterns by using a fault dictionary that describes responses of one or more modeled faults to the failing test patterns;
simulating one or more fault candidates of the determined set using passing test patterns, failing test patterns, or both failing and passing test patterns; and
storing the one or more fault candidates and results of the simulating one or more fault candidates on one or more computer-readable media. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of diagnosing one or more defects in an electronic circuit, the method comprising:
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determining a portion of a first list of candidate faults for one or more failing test patterns applied to the electronic circuit, the determination being made using a description of one or more modeled faults and circuit responses produced by the one or more modeled faults;
performing fault simulation of at least some of the candidate faults of the first list to determine a second list of candidate faults; and
storing at least one of the first or second lists in one or more computer-readable media. - View Dependent Claims (8, 9, 10)
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11. A method of diagnosing defects in an electronic circuit comprising two or more clocks, the method comprising:
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selecting one or more passing test patterns for simulation with one or more fault candidates of the electronic circuit, wherein the passing test patterns are selected based at least in part on associations of the one or more passing test patterns with one or more clocks associated with the one or more fault candidates; and
storing the selection in one or more computer-readable media. - View Dependent Claims (12, 13, 14, 15)
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16. A method of generating a fault dictionary for use in diagnosing faults in an electronic circuit, the method comprising:
for a selected fault, simulating one or more test patterns being applied to the electronic circuit in the presence of the selected fault;
determining test responses to the one or more test patterns that indicate the presence of the selected fault using the simulation; and
storing, in one or more computer-readable media, a fault dictionary entry that identifies the selected fault and identifies the test responses that indicate the presence of the selected fault. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24)
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25. A method of generating a fault dictionary for use in diagnosing faults in an electronic circuit, the method comprising:
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determining, for a selected fault, that a first test pattern and a second test pattern detect the selected fault and produce a same respective signature; and
storing in one or more computer-readable media one fault dictionary entry for the first and second failing test patterns. - View Dependent Claims (26, 27, 28, 29, 30, 31)
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32. A method of generating a fault dictionary for diagnosing faults in an electronic circuit, the method comprising:
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simulating one or more faults in a representation of the electronic circuit as one or more test patterns are applied to the representation;
selecting one or more failing test patterns from the simulation results;
identifying one or more unique failing bit combinations for the selected failing patterns;
creating one or more signatures from the one or more unique failing bit combinations; and
storing the one or more signatures in one or more computer-readable media. - View Dependent Claims (33, 34, 35, 36, 37, 38)
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39. A method of diagnosing one or more faults in an electronic circuit, the method comprising:
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determining if a failing test pattern applied to the circuit comprises more than a threshold number of failing bits, wherein the threshold number is greater than one;
if the pattern does not comprise more than the threshold number of failing bits;
determining a signature for the failing test pattern;
determining one or more fault candidates associated with the signature using a dictionary; and
storing one or more of the fault candidates in one or more computer-readable media. - View Dependent Claims (40, 41, 42, 43, 44)
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Specification