Cell-aware diagnostic pattern generation for logic diagnosis

1. One or more non-transitory computer-readable media storing computer-executable instructions, the computer-executable instructions, when executed, causing one or more processors to perform a method, the method comprising:

performing a first diagnosis process on a failed integrated circuit based on a first fail log, a first set of test patterns and a circuit design based on which the failed integrated circuit is fabricated to generate a first set of defect suspects that define one or more cells in the circuit design, thereby identifying one or more defective cells in the circuit design, wherein the first fail log is generated by applying the first set of test patterns to the failed integrated circuit in a first scan-based test, the first fail log including information describing when, where, and how a test failed and which of the first set of test patterns generate expected test responses;

based on identifying the one or more suspect defective cells, generating a second set of test patterns using fault models for internal defects in the one or more suspect defective cells, the second set of test patterns capable of detecting each of the fault models for internal defects in the one or more suspect defective cells for at least a predetermined number of times;

performing a second diagnosis process on the failure integrated circuit based on a second fail log, the second set of test patterns and the circuit design to generate a second set of defect suspects, the second fail log generated by applying the second set of test patterns to the failure integrated circuit in a second scan-based test; and

reporting the second set of defect suspects.

2. The one or more non-transitory computer-readable media recited in claim 1 , wherein each of the first diagnosis process and the second diagnosis process comprises failing test pattern simulations and passing test pattern simulations.

3. The one or more non-transitory computer-readable media recited in claim 1 , wherein the fault models for internal defects in the one or more cells are generated based on fault simulation.

4. The one or more non-transitory computer-readable media recited in claim 1 , wherein the fault models for internal defects in the one or more cells are exhaustive fault models covering all possible one-cycle and two-cycle input combinations and all possible fault effect propagation scenarios at all outputs of a cell.

5. The one or more non-transitory computer-readable media recited in claim 1 , wherein the generating a second set of test patterns comprises:

generating two-time-frame test patterns; and generating one-time-frame test patterns.

6. The one or more non-transitory computer-readable media recited in claim 1 , wherein the reporting comprises storing the second set of defect suspects.

7. A method, executed by at least one processor of a computer, comprising:

performing a first diagnosis process on a failed integrated circuit based on a first fail log, a first set of test patterns and a circuit design based on which the failed integrated circuit is fabricated to generate a first set of defect suspects that define one or more cells in the circuit design, thereby identifying one or more defective cells in the circuit design, wherein the first fail log is generated by applying the first set of test patterns to the failed integrated circuit in a first scan-based test, the first fail log including information describing when, where, and how a test failed and which of the first set of test patterns generate expected test responses;

based on identifying the one or more suspect defective cells, generating a second set of test patterns using fault models for internal defects in the one or more suspect defective cells, the second set of test patterns capable of detecting each of the fault models for internal defects in the one or more suspect defective cells for at least a predetermined number of times;

performing a second diagnosis process on the failure integrated circuit based on a second fail log, the second set of test patterns and the circuit design to generate a second set of defect suspects, the second fail log generated by applying the second set of test patterns to the failure integrated circuit in a second scan-based test; and

reporting the second set of defect suspects.

8. The method recited in claim 7 , wherein each of the first diagnosis process and the second diagnosis process comprises failing test pattern simulations and passing test pattern simulations.

9. The method recited in claim 7 , wherein the fault models for internal defects in the one or more cells are generated based on fault simulation.

10. The method recited in claim 7 , wherein the fault models for internal defects in the one or more cells are exhaustive fault models covering all possible one-cycle and two-cycle input combinations and all possible fault effect propagation scenarios at all outputs of a cell.

11. The method recited in claim 7 , wherein the generating a second set of test patterns comprises: generating two-time-frame test patterns; and generating one-time-frame test patterns.

12. The method recited in claim 7 , wherein the reporting comprises storing the second set of defect suspects.

13. A system comprising: one or more processors, the one or more processors programmed to perform a method, the method comprising:

performing a first diagnosis process on a failed integrated circuit based on a first fail log, a first set of test patterns and a circuit design based on which the failed integrated circuit is fabricated to generate a first set of defect suspects that define one or more cells in the circuit design, thereby identifying one or more defective cells in the circuit design, wherein the first fail log is generated by applying the first set of test patterns to the failed integrated circuit in a first scan-based test, the first fail log including information describing when, where, and how a test failed and which of the first set of test patterns generate expected test responses;

based on identifying the one or more suspect defective cells, generating a second set of test patterns using fault models for internal defects in the one or more suspect defective cells, the second set of test patterns capable of detecting each of the fault models for internal defects in the one or more suspect defective cells for at least a predetermined number of times;

performing a second diagnosis process on the failure integrated circuit based on a second fail log, the second set of test patterns and the circuit design to generate a second set of defect suspects, the second fail log generated by applying the second set of test patterns to the failure integrated circuit in a second scan-based test; and

reporting the second set of defect suspects.

14. The system recited in claim 13 , wherein each of the first diagnosis process and the second diagnosis process comprises failing test pattern simulations and passing test pattern simulations.

15. The system recited in claim 13 , wherein the fault models for internal defects in the one or more cells are generated based on fault simulation.

16. The system recited in claim 13 , wherein the fault models for internal defects in the one or more cells are exhaustive fault models covering all possible one-cycle and two-cycle input combinations and all possible fault effect propagation scenarios at all outputs of a cell.

17. The system recited in claim 13 , wherein the generating a second set of test patterns comprises:

generating two-time-frame test patterns; and

generating one-time-frame test patterns.

18. The system recited in claim 13 , wherein the post-layout verification process wherein the reporting comprises storing the second set of defect suspects.