Dielectric breakdown monitor

Patent metadata

Field	Value
Publication number	US-10564213-B2
Application number	US-201715443688-A
Country	US
Kind code	B2
Filing date	Feb 27, 2017
Priority date	Feb 27, 2017
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

A method and system of monitoring a reliability of a semiconductor circuit are provided. A current consumption of a first ring oscillator that is in static state is measured at predetermined intervals. Each measured current consumption value is stored. A baseline current consumption value of the first ring oscillator is determined based on the stored current consumption values. A latest measured current consumption value of the first ring oscillator is compared to the baseline current consumption value. Upon determining that the latest measured current consumption value is above a threshold deviation from the baseline current consumption value, the first ring oscillator is identified to have a dielectric breakdown degradation.

First claim

What is claimed is:

1. A semiconductor reliability monitor comprising:
a first ring oscillator maintained under a reference stress voltage while in a static state;
a current sensor configured to measure a current consumption value of the first ring oscillator while the first ring oscillator is in the static state, wherein the current consumption measurement is performed at predetermined intervals; and
a controller coupled to the first ring oscillator, wherein the controller is configured to:
receive and store each measured current consumption value of the first ring oscillator while in the static state, in a memory;
determine a baseline current consumption value of the first ring oscillator based on the stored current consumption values;
compare a latest measured current consumption value of the first ring oscillator to the baseline current consumption value; and
upon determining that the latest measured current consumption value is above a threshold deviation from the baseline current consumption value, identify the first ring oscillator to have a dielectric breakdown.

2. The semiconductor reliability monitor of claim 1 , wherein:
the first ring oscillator also has an active state that allows the first ring oscillator to oscillate; and
the controller is further configured to keep the first ring oscillator in a default static state unless performing a frequency of oscillation measurement on the first ring oscillator.

3. The semiconductor reliability monitor of claim 1 , wherein the controller is further configured to:
activate an active state of the first ring oscillator;
determine a frequency of oscillation of the first ring oscillator for a predetermined time period during the active state; and
determine whether there is a BTI and HCI degradation based on the frequency of oscillation of the first ring oscillator.

4. The semiconductor reliability monitor of claim 3 , wherein determining whether there is BTI degradation and HCI degradation comprises:
comparing the frequency of oscillation of the first ring oscillator to a reference value; and
upon determining that the frequency of oscillation is below a predetermined threshold of the reference value, identifying the first ring oscillator to have BTI and HCI degradation.

5. The semiconductor reliability monitor of claim 1 , further comprising a second ring oscillator maintained without a reference stress voltage while in a static state.

6. The semiconductor reliability monitor of claim 5 , wherein the controller is further configured to:
activate an active state of the first and second ring oscillators for a predetermined time period;
determine a frequency of oscillation of the first ring oscillator and the second ring oscillator during the predetermined time period; and
upon determining that the frequency of oscillation of the first ring oscillator is below a threshold variation from the second ring oscillator, identifying the first ring oscillator to have a BTI and HCI degradation.

7. The semiconductor reliability monitor of claim 6 , wherein the frequency of oscillation of the first ring oscillator and the second ring oscillator are determined concurrently.

8. The semiconductor reliability monitor of claim 5 , further comprising a third ring oscillator maintained in a free running state and at the reference stress voltage, wherein the controller is further configured to:
activate an active state of the second ring oscillator for a predetermined time period;
determine a frequency of oscillation of the second ring oscillator and the third ring oscillator, during the predetermined time period; and
upon determining that the frequency of oscillation of the third ring oscillator is below a threshold variation from the second ring oscillator, identifying the third ring oscillator to have a BTI and HCI degradation.

9. The semiconductor reliability monitor of claim 5 , further comprising a third ring oscillator maintained in a free running state and at the reference voltage, wherein controller is further configured to:
activate an active state of the first ring oscillator for a predetermined time period;
determine a frequency of oscillation of the first ring oscillator and the third ring oscillator, during the predetermined time period; and
upon determining that the frequency of oscillation of the third ring oscillator is below a threshold variation from the first ring oscillator, identifying the third ring oscillator to have a BTI and HCI degradation.

10. The semiconductor reliability monitor of claim 5 , wherein the controller is configured to activate the first and second oscillators at a same time and deactivate the first and second oscillators at a second same time.

11. A method of monitoring a degradation of a semiconductor circuit, comprising:
measuring a current consumption of a first ring oscillator in static state at predetermined intervals;
storing each measured current consumption value of the first ring oscillator in the static state;
determining a baseline current consumption value of the first ring oscillator based on the stored current consumption values;
comparing a latest measured current consumption value of the first ring oscillator to the baseline current consumption value; and
upon determining that the latest measured current consumption value is above a threshold deviation from the baseline current consumption value, identifying the first ring oscillator to have a dielectric breakdown.

12. The method of claim 11 , wherein the first ring oscillator is maintained under a reference stress voltage while in a static state.

13. The method of claim 11 , further comprising keeping the first ring oscillator in a default static state unless performing a frequency of oscillation measurement on the first ring oscillator.

14. The method of claim 11 , further comprising:
activating an active state of the first ring oscillator;
determining a frequency of oscillation of the first ring oscillator for a predetermined time period during the active state; and
determining whether there is a BTI and HCI degradation based on the frequency of oscillation of the first ring oscillator.

15. The method of claim 14 , wherein determining whether there is BTI and HCI degradation comprises:
comparing the frequency of oscillation of the first ring oscillator to a reference value; and
upon determining that the frequency of oscillation is below a predetermined threshold of the reference value, identifying the first ring oscillator to have BTI and HCI degradation.

16. The method of claim 11 , further comprising maintaining a second ring oscillator without a reference stress voltage while in a static state.

17. The method of claim 16 , further comprising:
activating an active state of the first and second ring oscillators for a predetermined time period;
determining a frequency of oscillation of the first ring oscillator and the second ring oscillator during the predetermined time period; and
upon determining that the frequency of oscillation of the first ring oscillator is below a threshold variation from the second ring oscillator, identifying the first ring oscillator to have a BTI and HCI degradation.

18. The method of claim 17 , wherein the frequency of oscillation of the first ring oscillator and the second ring oscillator are determined concurrently.

19. The method of claim 16 , further comprising:
maintaining a third ring oscillator in a free running state and at the reference stress voltage;
activating an active state of the second ring osci

Assignees

• IBM

Inventors

• Huynh Tam N
• Jenkins Keith A
• Stellari Franco

Classifications

• H03K3/0315

  Ring oscillators · CPC title

• G01R31/129 Primary

  of components or parts made of semiconducting materials; of LV components or parts (G01R31/18 takes precedence) · CPC title

• G01R31/14

  Circuits therefor {, e.g. for generating test voltages, sensing circuits (G01R31/1209 - G01R31/1227 take precedence; for testing switches G01R31/327)} · CPC title

• G01R31/3008

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