Method of predicting microprocessor lifetime reliability using architecture-level structure-aware techniques

• US 7,472,038 B2
• Filed: 04/16/2007
• Issued: 12/30/2008
• Est. Priority Date: 04/16/2007
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bose, Pradip, Hu, Zhigang, Zyuban, Victor, Shin, Jeonghee, Rivers, Jude A.
• Primary Examiner(s): Raymond; Edward
• Assistant Examiner(s): Desta; Elias
• Application Number:
  US11/735,533
• Publication Number:
  US 20080256383A1
• Time in Patent Office: 624 Days
• Field of Search: 702 81- 84, 702/182, 702/186, 700108-110, 324/500, 324/537, 324760-765, 714/1, 714/47, 714/25
• US Class Current: 702/182
• CPC Class Codes: G06F 11/008 Reliability or availability analysis

Abstract

A method of predicting the lifetime reliability of an integrated circuit device with respect to one or more failure mechanisms includes breaking down the integrated circuit device into structures; breaking down each structure into elements and devices; evaluating each device to determine whether the device is vulnerable to the failure mechanisms and eliminating devices determined not to be vulnerable; estimating, for each determined vulnerable device, the impact of a failure of the device on the functionality of the specific element associated therewith, and classifying the failure into a fatal failure or a non-fatal failure, wherein a fatal failure causes the element employing the given device to fail; determining, for those devices whose failures are fatal, an effective stress degree and/or time; determining one or more of a failure rate and a probability of fatal failure for the devices, and aggregating the same across the structures and the failure mechanisms.

Claims

1. A method of predicting the lifetime reliability of an integrated circuit device with respect to one or more defined failure mechanisms, the method comprising:

breaking down the integrated circuit device into microarchitecture structures;

further breaking down each structure into one or more of elements and devices, with a device comprising a sub-component of an element;

determining, for each vulnerable device, the impact of a failure of the device on the functionality of the specific element associated therewith, and classifying the failure into one of a fatal failure and a non-fatal failure, wherein a fatal failure of a given device is one in which the failure causes the element employing the given device to fail;

determining, for those devices whose failures are classified as fatal, one or more of an effective stress degree and an effective stress time based on one or more architecture-level events and states;

determining one or more of a failure rate and a probability of fatal failure for the devices, using the one or more of the associated effective stress degree and effective stress time; and

aggregating the one or more of the failure rate of the devices and the probability of fatal failures of the devices, across the structures for the one or more defined failure mechanisms.

2. The method of claim 1, wherein the structures include one or more of:

register files, arrays, control logic, data paths, multiplexers, latches, repeated wires, and logic gates.

3. The method of claim 1, wherein the elements include one or more of:

array/register file bitlines, array/register file wordlines, memory cells, gates of transistors, and wire repeaters.

4. The method of claim 1, wherein the devices include one or more of:

metal lines, vias, PFET devices, and NFET devices.

5. The method of claim 1, wherein the failure mechanisms include one or more of:

electromigration (EM), negative bias temperature instability (NBTI) and time dependent dielectric breakdown (TDDB).

6. The method of claim 5, further comprising evaluating each device to determine whether the device is vulnerable to the one or more defined failure mechanisms and eliminating from consideration those devices determined not to be vulnerable.

7. The method of claim 6, wherein a device vulnerable to electromigration comprises at least one of a metal line and a via dominated by unidirectional current flow therethrough.

8. The method of claim 6, wherein a device vulnerable to NBTI comprises a PFET device having a negative gate bias applied thereto.

9. The method of claim 6, wherein a device vulnerable to TDDB comprises one or more of:

a PFET device having a logic low gate voltage and one of a logic high source and drain, and an NFET device having a logic high gate voltage and one of a logic low source and drain.

10. The method of claim 6, wherein a fatal failure of a device due to electromigration comprises a condition in which a failure of one of a metal line and a via leads to one or more of a short circuit, an open circuit, and a timing violation due to increased wire resistance.

11. The method of claim 6, wherein a fatal failure of a device due to NBTI comprises a condition in which a failure of a PFET device along a critical path leads to a timing violation.

12. The method of claim 6, wherein a fatal failure of a device due to TDDB comprises a condition in which one or more of a PFET device and an NFET device has leakage current through a gate oxide thereof exceeds a value that is able to be tolerated by logic driving the same.

13. The method of claim 6, wherein a device under stress for the electromigration failure mechanism comprises a via having current generated therethrough during one of a logical one-to-zero and a logical zero-to-one value transition of metal lines.

14. The method of claim 6, wherein a device under stress for the NBTI failure mechanism comprises a PFET device having a gate coupled to a logic low voltage and a source coupled to a logic high voltage.

15. The method of claim 6, wherein a device under stress for the TDDB failure mechanism comprises one or more of a PFET device having a gate coupled to a logic low voltage and a source coupled to a logic high voltage, and an NFET device having a gate coupled to a logic high voltage and a source coupled to a logic low voltage.

16. The method of claim 1, wherein architecture-level states comprise one or more of:

a number of accesses to the device, a number of access patterns to the device, and data patterns of inputs and outputs of the device.

17. The method of claim 1, wherein architectural configuration parameters include one or more of:

a number of cells in an array, a number of read ports, a number of write ports, and a number of data paths.

18. The method of claim 1, wherein defect density is calculated as the ratio of the number of fatal failures of the devices of each structure to the area of the structure.

19. The method of claim 18, wherein defect density for the electromigration failure mechanism is calculated by counting the number of vias having unidirectional current of each structure and dividing the total number of vias by the area of the structure.

20. The method of claim 18, wherein defect density for the NBTI failure mechanism is calculated by counting the number of PFETs along the critical paths of each structure and dividing the total number of PFETs by the area of the structure.

21. The method of claim 18, wherein defect density for the TDDB failure mechanism is calculated by counting the number of gate oxide breakdowns of both PFET and NFET devices of each structure, and dividing the total number of breakdowns by the area of the structure.

22. The method of claim 18, wherein the aggregating one or more of the failure rate of the devices and the probability of fatal failures of the devices is implemented by one or more of summation and weighted summation.

23. The method of claim 6, wherein the failure rates are computed in terms of a technology and environment independent failures-in-time (FIT) of a reference circuit (FORC) defined for each of the failure mechanisms.

24. The method of claim 23, wherein the failure rates are further computed in absolute values utilizing power and temperature maps along with technology and implementation parameters, by calculating the value of FORC for each component and multiplying the calculated FORC values by the technology/environment-independent values of the failure rates for each of the components.