Voltage rail monitoring to detect electromigration

Patent metadata

Field	Value
Publication number	US-9753076-B2
Application number	US-201615008802-A
Country	US
Kind code	B2
Filing date	Jan 28, 2016
Priority date	Jan 28, 2016
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

An integrated circuit is configured to detect current leakage that results from electromigration in the integrated circuit. An isolation power switch selectively connects a target voltage rail in the integrated circuit to a power source. A voltage memory stores a record of an initial voltage decay rate for the target voltage rail while isolated from a manufacturer's power source. A voltage record comparator logic compares the initial voltage decay rate to a field voltage decay rate for the target voltage rail when isolated from a field power source. An output device indicates that a difference between the initial voltage decay rate and the field voltage decay rate for the target voltage rail exceeds a predefined limit, where the difference is a result of current leakage caused by electromigration in the integrated circuit.

First claim

What is claimed is:

1. An integrated circuit comprising:
a target voltage rail, wherein the target voltage rail provides power to at least one circuit node in the integrated circuit;
an isolation power switch, wherein the isolation power switch selectively connects the target voltage rail to a power source;
a voltage sensor that couples the target voltage rail to a reference voltage source;
a memory supervisor coupled to the voltage sensor;
a voltage memory coupled to the memory supervisor, wherein the voltage memory stores a record of an initial voltage decay rate for the target voltage rail while isolated from a manufacturer's power source;
a clock coupled to the memory supervisor, wherein the clock triggers the memory supervisor to take serial voltage readings from the voltage sensor while the target voltage rail is isolated from a field power source to create a field voltage decay rate for the target voltage rail;
a voltage record comparator logic, wherein the voltage record comparator logic compares the initial voltage decay rate to the field voltage decay rate for the target voltage rail; and
an output device coupled to the voltage record comparator logic, wherein the output device describes a difference between the initial voltage decay rate and the field voltage decay rate for the target voltage rail that exceeds a predefined limit, and wherein the difference between the initial voltage decay rate and the field voltage decay rate for the target voltage rail is a result of current leakage in the integrated circuit.

2. The integrated circuit of claim 1 , wherein the current leakage is a result of electromigration in the integrated circuit.

3. The integrated circuit of claim 1 , wherein the initial voltage decay rate was recorded upon a final manufacturing of the integrated circuit.

4. The integrated circuit of claim 1 , wherein the initial voltage decay rate was recorded upon a final installation of the integrated circuit into a field replaceable unit (FRU), wherein the FRU is a field replaceable board for an electronic system.

5. The integrated circuit of claim 1 , wherein the reference voltage source is a ground.

6. The integrated circuit of claim 1 , wherein the reference voltage source is a reference voltage rail.

7. The integrated circuit of claim 6 , wherein the reference voltage rail provides a bias voltage to the target voltage rail.

8. The integrated circuit of claim 1 , wherein the output device is an input/output connector to a test device.

9. The integrated circuit of claim 1 , wherein the output device is an alarm indicator.

10. A field replaceable unit (FRU), wherein the FRU is a field replaceable board for an electronic device, and wherein the FRU comprises:
an integrated circuit that comprises:
a target voltage rail, wherein the target voltage rail provides power to at least one circuit node in the integrated circuit;
an isolation power switch, wherein the isolation power switch selectively connects the target voltage rail to a power source;
a voltage sensor that couples the target voltage rail to a reference voltage source;
a memory supervisor coupled to the voltage sensor;
a voltage memory coupled to the memory supervisor, wherein the voltage memory stores a record of an initial voltage decay rate for the target voltage rail while isolated from a manufacturer's power source;
a clock coupled to the memory supervisor, wherein the clock triggers the memory supervisor to take serial voltage readings from the voltage sensor while the target voltage rail is isolated from a field power source to create a field voltage decay rate for the target voltage rail;
a voltage record comparator logic, wherein the voltage record comparator logic compares the initial voltage decay rate to the field voltage decay rate for the target voltage rail; and
an output device coupled to the voltage record comparator logic, wherein the output device indicates that a difference between the initial voltage decay rate and the field voltage decay rate for the target voltage rail exceeds a predefined limit, and wherein the difference between the initial voltage decay rate and the field voltage decay rate for the target voltage rail is a result of current leakage caused by electromigration in the integrated circuit.

11. The FRU of claim 10 , wherein the initial voltage decay rate was recorded upon a final manufacturing of the integrated circuit.

12. The FRU of claim 10 , wherein the initial voltage decay rate was recorded upon a final installation of the integrated circuit into the FRU.

13. The FRU of claim 10 , wherein the reference voltage source is a ground.

14. The FRU of claim 10 , wherein the reference voltage source is a reference voltage rail.

15. The FRU of claim 14 , wherein the reference voltage rail provides a bias voltage to the target voltage rail.

16. The FRU of claim 10 , wherein the output device is an input/output connector to a test device.

17. The FRU of claim 10 , wherein the output device is an alarm indicator.

18. A computer program product for detecting electromigration in a field replaceable unit, the computer program product comprising a non-transitory computer readable storage medium having program code embodied therewith, the program code readable and executable by a processor to perform a method comprising:
quiescenting an integrated circuit that is within a field replaceable unit (FRU), wherein the FRU is a field replaceable board in an electronic device;
applying, via an isolation power switch, a test voltage from a field power source to a target voltage rail in the integrated circuit, wherein the test voltage is below an operational voltage for transistors within the integrated circuit;
isolating, via the isolation power switch, the target voltage rail from the field power source;
measuring, by a voltage sensor coupled to the target voltage rail, a field voltage decay rate for the target voltage rail, wherein the voltage sensor couples the target voltage rail to a reference voltage source;
comparing, via a voltage record comparator logic within the integrated circuit, the field voltage decay rate to an initial voltage decay rate for the target voltage rail; and
in response to a difference between the field voltage decay rate and the initial voltage decay rate for the target voltage rail exceeding a predetermined limit, sending, via the voltage record comparator logic, a signal to an alarm on the FRU, wherein the difference between the initial voltage decay rate and the field voltage decay rate for the target voltage rail has been predetermined to be a result of current leakage caused by electromigration in the integrated circuit.

19. The computer program product of claim 18 , wherein the initial voltage decay rate was recorded upon an installation of the integrated circuit into the field replaceable unit (FRU).

20. The computer program product of claim 18 , wherein the reference voltage source is a reference voltage rail that provides a bias voltage to the target voltage rail.

Assignees

• IBM

Inventors

• Cadigan David D
• Huott William V
• Mcpadden Adam J
• Saetow Anuwat
• Tressler Gary A

Classifications

• G01R31/2858

  Measuring of material aspects, e.g. electro-migration [EM], hot carrier injection · CPC title

• G01R31/3008 Primary

  Quiescent current [IDDQ] test or leakage current test · CPC title

• G01R31/2851

  Testing of integrated circuits [IC] (G01R31/317 takes precedence; testing individual devices G01R31/26; testing printed circuits G01R31/2801) · CPC title

• G01R31/2856

  Internal circuit aspects, e.g. built-in test features; Test chips; Measuring material aspects, e.g. electro migration [EM] · CPC title

• G01R31/024

  Physics · mapped topic