Method for measuring a behavior of a MEMS device

Patent metadata

Field	Value
Publication number	US-11137253-B2
Application number	US-201816500908-A
Country	US
Kind code	B2
Filing date	Jul 10, 2018
Priority date	Jul 12, 2017
Publication date	Oct 5, 2021
Grant date	Oct 5, 2021

Abstract

A method for measuring a behavior of a MEMS device is disclosed. In an embodiment a method includes mounting the MEMS device to a testing apparatus that comprises a vibration source, wherein the MEMS device comprises a 6-axis or 9-axis inertial sensor, applying a vibration to the MEMS device by the vibration source and simultaneously moving the testing apparatus according to a predefined movement pattern, reading output data provided by the inertial sensor and comparing the output data to the predefined movement pattern and/or reading output data provided by the inertial sensor and calculating a frequency response curve of the inertial sensor.

First claim

We claim:

1. A method for measuring a behavior of a MEMS device, the method comprising:
mounting the MEMS device to a testing apparatus that comprises a vibration source, wherein the MEMS device comprises a 6-axis or 9-axis inertial sensor;
applying a vibration to the MEMS device by the vibration source and simultaneously moving the testing apparatus according to a predefined movement pattern;
reading output data provided by the inertial sensor and comparing the output data to the predefined movement pattern; and/or
reading output data provided by the inertial sensor and calculating a frequency response curve of the inertial sensor,
wherein moving the testing apparatus according to the predefined movement pattern comprises tilting the testing apparatus at a defined angular rate in different directions, and
wherein reading output data provided by the inertial sensor comprises calculating a roll angle and a pitch angle based on the output data provided by the inertial sensor.

2. The method according to claim 1 ,
wherein the testing apparatus comprises a 3-axis accelerometer configured to measure a frequency of the applied vibration,
wherein the frequency of the applied vibration is varied, and
wherein the frequency response curve is calculated based on the output data by the inertial sensor and data provided by the 3-axis accelerometer.

3. The method according to claim 1 , wherein comparing the output data to the predefined movement patter comprises determining, by a software algorithm, whether a difference between the output data provided by the inertial sensor and the predefined movement pattern is within a predetermined acceptance limit.

4. The method according to claim 1 , wherein the output data provided by the inertial sensor are evaluated using a sensor fusion algorithm comprising a Kalman filter before comparing the output data to the predefined movement pattern.

5. The method according to claim 1 , wherein the inertial sensor comprises a gyroscope.

6. The method according to claim 1 ,
wherein the inertial sensor is resiliently mounted on a carrier by spring elements,
wherein an air gap is provided between a top surface of the carrier and a bottom surface of the inertial sensor, and
wherein a damping structure is applied to at least one surface chosen from a first surface located on the carrier or a second surface located on the inertial sensor.

7. The method according to claim 6 ,
wherein the damping structure is applied as a layer between the inertial sensor and the carrier on one of the first surface or the second surface,
wherein the layer comprises recesses, and
wherein the recesses are at least measured to accommodate the spring elements.

8. The method according to claim 6 ,
wherein the spring elements comprise an extended structure that is linear, bent or angled,
wherein a first end of the extended structure is coupled to a first anchor point on the carrier,
wherein a second end of the extended structure is coupled to a second anchor point on a sensor system, and
wherein a height of the air gap normal to the surface is smaller than a distance normal to the surface between first and second anchor point.

9. The method according to claim 1 , wherein the inertial sensor is encapsulated in a sealed package.

10. The method according to claim 1 , wherein mounting the MEMS device comprises mounting a plurality of MEMS devices to the testing apparatus, and wherein the behavior of the plurality of MEMS devices is measured simultaneously.

11. The method according to claim 1 , wherein applying the vibration to the MEMS device by the vibration source comprises applying the vibration continuously.

12. The method according to claim 1 , wherein applying the vibration to the MEMS device by the vibration source comprises applying the vibration discontinuously.

13. The method according to claim 1 , wherein moving the testing apparatus comprises rotating the testing apparatus at an angular rate in a range of 0.001 deg/s to 1000 deg/s.

14. The method according to claim 1 , wherein applying the vibration to the MEMS device by the vibration source comprises vibrating the vibration source with a frequency in a range of 0.1 kHz to 1000 kHz and with an amplitude in a range of 1 nm to 10 μm.

Assignees

• Tdk Corp

Inventors

• Barbul Andreas
• Pahl Wolfgang

Classifications

• B81C99/0045 Primary

  End test of the packaged device · CPC title

• G01P15/0802

  Details · CPC title

• B81B2201/0242

  Gyroscopes · CPC title

• G01P15/18

  in two or more dimensions · CPC title

• G01C19/56

  Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces · CPC title