Granted Patent B2

US 8,969,102 · App. 13/887,233 · Granted Mar 3, 2015

Abstract

Claims (41)

1. A method of testing a device, the method comprising:

setting a potential of a cap terminal of the device to a first voltage;

setting a potential of a self test plate of the device to a testing voltage;

detecting a first displacement of a proof mass of the device when the cap terminal is set to the first voltage and the self test plate is set to the testing voltage;

setting a potential of the cap terminal of the device to a second voltage;

detecting a second displacement of the proof mass of the device when the cap terminal is set to the second voltage and the self test plate is set to the testing voltage; and

comparing the first displacement and the second displacement to evaluate an electrical connection between the cap terminal of the device and a cap of the device.

2. The method of claim 1 , wherein comparing the first displacement and the second displacement to evaluate the electrical connection between the cap terminal and the cap includes determining a difference between the first displacement and the second displacement.

3. The method of claim 2 , including comparing the difference between the first and second displacement to a threshold value.

4. The method of claim 1 , wherein the device is an accelerometer.

5. The method of claim 1 , wherein the second voltage is the testing voltage.

6. The method of claim 1 , wherein the first voltage is a voltage of the proof mass of the device.

7. A method of testing a device, the method comprising:

detecting a first displacement of a proof mass of the device when a potential of a cap terminal of the device is set to a first voltage;

measuring a time period from when the potential of the cap terminal of the device is set to the first voltage to the first displacement of the proof mass is detected; and

comparing the measured time period to a threshold to evaluate an electrical connection between the cap terminal of the device and a cap of the device.

8. The method of claim 7 , including:

detecting a second displacement of the proof mass of the device when the potential of the cap terminal of the device is set to a second voltage; and

comparing the first displacement and the second displacement to evaluate the electrical connection between the cap terminal and the cap of the device.

9. The method of claim 8 , including, before detecting a first displacement of a proof mass of the device, setting a potential of a self test plate of the device to a first self test voltage.

10. The method of claim 9 , including, before detecting a second displacement of a proof mass of the device, setting a potential of a self test plate of the device to a second self test voltage.

11. The method of claim 10 , wherein the second self test voltage is the same as the first self test voltage.

12. The method of claim 8 , wherein comparing the first displacement and the second displacement to evaluate the electrical connection between the cap terminal and the cap includes determining a difference between the first displacement and the second displacement.

13. The method of claim 12 , including comparing the difference between the first and second displacement to a threshold value.

14. A method of manufacturing a device, the method comprising:

fabricating the device on a substrate, the device including a cap, a cap terminal, and a proof mass;

testing an electrical connection between the cap and the cap terminal by:

detecting a first displacement of the proof mass of the device when a potential of the cap terminal of the device is set to a first voltage,

detecting a second displacement of the proof mass of the device when the potential of the cap terminal of the device is set to a second voltage, and

comparing the first displacement and the second displacement to determine whether the cap terminal and the cap of the device are electrically connected; and

when the cap terminal and the cap of the device are determined to be electrically connected,

singulating the substrate, and

providing the device to a recipient.

15. The method of claim 14 , including, when the cap terminal and the cap of the device are determined to be not electrically connected:

discarding the device.

16. The method of claim 14 , wherein comparing the first displacement and the second displacement to determine whether the cap terminal and the cap of the device are electrically connected includes determining a difference between the first displacement and the second displacement.

17. The method of claim 16 , including comparing the difference between the first and second displacement to a threshold value.

18. The method of claim 14 , wherein the device is an accelerometer.

19. The method of claim 14 , including:

when detecting the first displacement, setting a potential of a self test plate of the device to a self test voltage; and

when detecting the second displacement, setting the potential of the self test plate of the device to the self test voltage.

Assignments (23)