DIAGNOSING MIXED SCAN CHAIN AND SYSTEM LOGIC DEFECTS
First Claim
1. A method, comprising:
- receiving a failure log indicative of failing test bits observed during testing of an electronic circuit, the electronic circuit having at least one defect in system logic and at least one defect in a scan chain;
identifying one or more fault suspects in the system logic of the electronic circuit;
identifying one or more fault suspects in the at least one scan chain of the electronic circuit; and
storing a description of the identified one or more fault suspects in the system logic and of the identified one or more fault suspects in the at least one scan chain in one or more computer-readable media.
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Accused Products
Abstract
Technologies disclosed herein can be used to diagnose defects on die having both scan chain and system logic defects, including in situations where the presence of one or more faults in the system logic potentially obscures the detectability of one or more faults in the scan chains (or channels) and vice versa. At least some embodiments employ an iterative approach where at least some scan chain faults are identified, these chain faults are used to identify system logic faults, and then additional chain faults are identified using the system logic faults and vice versa. Failing bits can be partitioned into at least two groups: failing bits determined as being caused by system logic failures, and failing bits determined as being possibly caused by chain defects, system logic defects, or the compound effects of both types of defects.
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Citations
43 Claims
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1. A method, comprising:
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receiving a failure log indicative of failing test bits observed during testing of an electronic circuit, the electronic circuit having at least one defect in system logic and at least one defect in a scan chain;
identifying one or more fault suspects in the system logic of the electronic circuit;
identifying one or more fault suspects in the at least one scan chain of the electronic circuit; and
storing a description of the identified one or more fault suspects in the system logic and of the identified one or more fault suspects in the at least one scan chain in one or more computer-readable media. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A system comprising:
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a component configured to receive a failure log indicative of failing test bits observed during testing of an electronic circuit, the electronic circuit comprising system logic and one or more scan chains and having at least one defect in the system logic and at least one defect in the one or more scan chains;
a component configured to identify one or more fault suspects in the system logic of the electronic circuit; and
a component configured to identify one or more fault suspects in the one or more scan chains of the electronic circuit. - View Dependent Claims (19)
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20. One or more computer-readable media comprising instructions configured to cause a computer to perform a method comprising:
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performing logic diagnosis on an electronic circuit while masking one or more faulty scan chains in the electronic circuit to produce logic diagnosis results;
performing scan chain diagnosis on the electronic circuit while masking one or more system logic defects in the electronic circuit to produce scan chain diagnosis results; and
storing the logic diagnosis results and the scan chain diagnosis results. - View Dependent Claims (21, 22, 23)
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24. A method, comprising:
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receiving a failure log indicative of failing test bits observed during testing of an electronic circuit;
performing chain diagnosis for the at least one scan chain to produce chain diagnosis results, the chain diagnosis results comprising one or more scan chain fault suspects;
determining scores for one or more of the scan chain fault suspects, the score for a respective one of the scan chain fault suspects indicating whether the respective scan chain fault suspect completely or partially explains the failing test bits observed; and
storing the scores in one or more computer-readable media. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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31. A method for diagnosing system logic faults in an electronic circuit, the method comprising:
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receiving test results obtained by applying scan pattern loading values to the electronic circuit during testing, the test results including failing bits caused by one or more system logic defects in the electronic circuit;
receiving modified scan patterns, the modified scan patterns comprising the scan pattern loading values modified such that values loaded into faulty scan chains have an unknown value, the modified scan patterns further comprising scan pattern unloading values modified such that values unloaded from the faulty scan chains have the unknown value; and
performing system logic diagnosis of the electronic circuit using the failing bits caused by the one or more system logic values and the modified scan patterns. - View Dependent Claims (32, 33, 34, 35, 36, 37)
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38. A method of analyzing data from a test of an electronic circuit having one or more system logic defects and one or more scan chain defects, the data indicating the presence of the one or more system logic defects and the one or more scan chain defects, the method comprising:
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identifying from the data a group of one or more failing bits determined as being caused by the one or more system logic defects; and
storing the identified group of one or more failing bits in one or more computer-readable media. - View Dependent Claims (39, 40, 41, 42, 43)
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Specification