Techniques for logic built-in self-test diagnostics of integrated circuit devices
View Patent ↗A method, system and computer program product for performing real-time LBIST diagnostics of IC devices. During LBIST, stump data and identifiers of test cycles are saved in the IC device-under-test (DUT). If compressed stump data does not match a pre-defined coded value (i.e., “signature” of the test cycle), the saved stump data and an identifier of the failed test cycle are preserved, otherwise the determination is made the DUT passed the test cycle. Identifiers and stump of the failed test cycles are used to analyze errors, including virtually non-reproducible errors.
1. A method of performing Logic Built-In Self-Test (LBIST) in an integrated circuit (IC) device, the method comprising:
storing in memory an identifier of a test cycle of the LBIST and stump data of scan chains of the IC device; and
determining by logic whether a compressed form of the stump data matches a pre-defined coded value;
if the compressed form of the stump data does not match the pre-defined coded value, then (i) determining that the IC device failed the test cycle and (ii) preserving the stored stump data and identifier of the test cycle that caused the IC device to fail; or
if the compressed form of the stump data matches the pre-defined coded value, determining that the IC device passed the test cycle,
wherein the identifier of the test cycle is associated with a particular test pattern for enabling subsequent analysis of sparse error data.
2. The method of claim 1 , further comprising:
replacing the stump data and the identifier of the test cycle that produced a match with the pre-defined coded value with a stump data and an identifier of a following test cycle of the LBIST.
3. The method of claim 1 , further comprising:
saving the stump data and the identifier of the test cycle in a library of pre-defined coded values.
4. The method of claim 1 , further comprising:
saving at least one of the stump data and the identifier of the test cycle using a compressed data format.
5. The method of claim 1 , wherein the identifier of the test cycle is one of a bit word or a numerical value.
6. The method of claim 1 , further comprising:
reading out the stored stump data and the identifier of the test cycle that caused the IC device to fail via an interface of the IC device.
7. The method of claim 6 , further comprising:
performing circuit simulation analysis using the stored stump data and the identifier of the test cycle that was read out from the interface of the IC device.
8. An integrated circuit (IC) device, comprising:
one or more functional circuits;
a system for performing Logic Built-In Self-Test (LBIST) of the one or more functional circuits; and
a memory including a library of pre-defined coded values and containing a code of a program that performs operations including:
storing in memory an identifier of a test cycle of the LBIST and stump data of scan chains of the IC device; and
determining by logic whether a compressed form of the stump data matches a pre-defined coded value;
if the compressed form of the stump data does not match the pre-defined coded value, then (i) determining that the IC device failed the test cycle and (ii) preserving the stored stump data and identifier of the test cycle that caused the IC device to fail; or
if the compressed form of the stump data matches the pre-defined coded value, determining that the IC device passed the test cycle.
wherein the identifier of the test cycle is associated with a particular test pattern for enabling subsequent analysis of sparse error data.
9. The IC device of claim 8 , said device configured to replace the stump data and the identifier of the test cycle that produced a match with the pre-defined coded value with a stump data and an identifier of a following test cycle of the LBIST.
10. The IC device of claim 8 , said device configured to save the stump data and the identifier of the test cycle in the library of pre-defined coded values.
11. The IC device of claim 8 , wherein at least one of the stump data and the identifier of the test cycle is saved using a compressed data format.
12. The IC device of claim 8 , wherein the identifier of the test cycle is one of a bit word or a numerical value.
13. The IC device of claim 8 , further comprising an interface for reading out the stored stump data and the identifier of the test cycle that caused the IC device to fail.
14. A non-transitory computer readable medium having a computer program product performing Logic Built-In Self-Test (LBIST) diagnostics in an integrated circuit (IC) device, said computer readable medium comprising:
computer program code for storing in memory an identifier of a test cycle of the LBIST and stump data of scan chains of the IC device; and
computer program code for determining by logic whether a compressed form of the stump data matches a pre-defined coded value;
computer program code for preserving the stored stump data and identifier of the test cycle in which the compressed form of the stump data does not match the pre-defined coded value; and
computer program code for, if the compressed form of the stump data does not match the pre-defined coded value, (i) determining that the IC device failed the test cycle; and (ii) preserving the stored stump data and identifier of the test cycle that caused the IC device to fail; and
computer program code for determining that the IC device passed the test cycle if the compressed form of the stump data matches the pre-defined coded value.
wherein the identifier of the test cycle is associated with a particular test pattern for enabling subsequent analysis of sparse error data.
15. The non-transitory computer readable medium of claim 14 , further comprising:
computer program code for replacing the stump data and the identifier of the test cycle that produced a match with the pre-defined coded value with a stump data and an identifier of a following test cycle of the LBIST.
16. The non-transitory computer readable medium of claim 14 , further comprising:
computer program code for saving the stump data and the identifier of the test cycle in a library of pre-defined coded values.
17. The non-transitory computer readable medium of claim 14 , further comprising:
computer program code for saving at least one of the stump data and the identifier of the test cycle using a compressed data format.
18. The non-transitory computer readable medium of claim 14 , further comprising:
computer program code for saving the identifier of the test cycle as a bit word or a numerical value.
19. The non-transitory computer readable medium of claim 14 , further comprising:
computer program code for reading out the stored stump data and the identifier of the test cycle that caused the IC device to fail via an interface of the IC device.
20. The non-transitory computer readable medium of claim 19 , further comprising:
computer program code for performing circuit simulation analysis using the stored stump data and the identifier of the test cycle that was read out from the interface of the IC device.