Systems and methods for operating a mems device based on sensed temperature gradients

Patent metadata

Field	Value
Publication number	US-11738994-B2
Application number	US-202218080169-A
Country	US
Kind code	B2
Filing date	Dec 13, 2022
Priority date	Aug 21, 2019
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

An exemplary microelectromechanical device includes a MEMS layer, portions of which respond to an external force in order to measure the external force. A substrate layer is located below the MEMS layer and an anchor couples the substrate layer and MEMS layer to each other. A plurality of temperature sensors are located within the substrate layer to identify a temperature gradient being experienced by the MEMS device. Compensation is performed or operations of the MEMS device are modified based on temperature gradient.

First claim

What is claimed is:

1. A microelectromechanical system (MEMS) device, comprising:
a first layer comprising a first plane;
a second layer comprising a second plane, wherein the second layer is located below the first layer;
at least one anchor, wherein the at least one anchor couples the first layer to the second layer;
a plurality of temperature sensors located within the second plane; and
one or more switching elements, wherein the one or more switching elements selectively monitor the plurality of temperature sensors, wherein the one or more switching elements selectively combine temperature sensor outputs from a first subset of the plurality of temperature sensors to measure a first temperature characteristic corresponding to the first subset, and wherein the one or more switching elements switch a second subset of the plurality of temperature sensors to reject a second temperature characteristic corresponding to the second subset, wherein the first temperature characteristic is a vertical thermal gradient perpendicular to the second layer and the second temperature characteristic is a lateral thermal gradient parallel to the second layer.

2. The MEMS device of claim 1 , wherein the one or more switching elements comprise switches, transistors, or MOSFETS.

3. The MEMS device of claim 1 , wherein the second layer comprises a center point, and wherein the at least one anchor is located vertically above the center point.

4. The MEMS device of claim 3 , wherein the at least one anchor comprises a plurality of anchors, each of the plurality of anchors positioned equidistant from the center point.

5. The MEMS device of claim 3 , wherein the plurality of temperature sensors includes a first temperature sensor, a second temperature sensor, a third temperature sensor, and a fourth temperature sensor;
wherein the first temperature sensor is positioned at a first location relative to the center point within the second layer, wherein a first response of the first temperature sensor changes based on a temperature at the first location;
wherein the second temperature sensor is positioned at a second location relative to the center point within the second layer, wherein the second location is on a first common measurement axis on an opposite side of the center point from the first location, and wherein a second response of the second temperature sensor changes based on a temperature at the second location;
wherein the third temperature sensor is positioned at a third location relative to the center point within the second layer, wherein a third response of the third temperature sensor changes based on a temperature at the third location, and wherein a first output value is based on the first response and the third response;
wherein the fourth temperature sensor is positioned at a fourth location relative to the center point within the second layer, wherein the fourth location is on a second common measurement axis on an opposite side of the center point from the third location, wherein a fourth response of the fourth temperature sensor changes based on a temperature at the fourth location, and wherein a second output value is based on the second response and the fourth response; and
processing circuitry configured to output a signal that corresponds to the vertical thermal gradient perpendicular to the second layer based on a change in a difference between the first output value and the second output value in response to the vertical thermal gradient, wherein the processing circuitry rejects the lateral thermal gradient within the second layer in outputting the signal.

6. The MEMS device of claim 5 , wherein the one or more switching elements select one or more of the plurality of temperature sensors to reconfigure the signal to change in response to a thermal gradient perpendicular to the second layer, a thermal gradient parallel to the second layer, an induced strain, or a temperature value.

7. The MEMS device of claim 5 , wherein the at least one anchor includes a first anchor and a second anchor, the first anchor being in contact with the first layer at a first anchoring location, the second anchor being in contact with the first layer at a second anchoring location, wherein the third temperature sensor of the plurality of temperature sensors is located below the first anchoring location, wherein the fourth temperature sensor of the plurality of temperature sensors is located below the second anchoring location, and wherein the first temperature sensor is spaced away along the first layer from the first anchoring location, and the second temperature sensor is spaced away along the first layer from the second anchoring location.

8. The MEMS device of claim 5 , wherein the first common measurement axis is orthogonal to the second common measurement axis.

9. The MEMS device of claim 5 , wherein the processing circuitry is configured to reject a variation in an output from one or more of the plurality of temperature sensors, the variation based on a strain induced on the one or more of the plurality of temperature sensors.

10. The MEMS device of claim 9 , wherein the first and the second temperature sensors are equidistant from the center point within the second layer, and wherein the third and the fourth temperature sensors are equidistant from the center point within the second layer.

11. The MEMS device of claim 5 , wherein an output from one or more of the plurality of temperature sensors changes based on a strain induced on the one or more of the plurality of temperature sensors, respectively, such that the signal changes in response to the strain induced on the one or more of the plurality of temperature sensors.

12. The MEMS device of claim 5 , wherein the plurality of temperature sensors is configured in a Wheatstone bridge, and wherein the processing circuitry is coupled to the plurality of temperature sensors via the Wheatstone bridge.

13. The MEMS device of claim 5 , wherein the processing circuitry is configured to reject the lateral thermal gradient within the second layer based on a proportional response of the first output value and the second output value to the lateral thermal gradient.

14. The MEMS device of claim 1 , wherein the first layer and the second layer define a gap between the first layer and the second layer, and wherein the at least one anchor is located within the gap.

15. The MEMS device of claim 1 , wherein the first plane is parallel to the second plane.

16. The MEMS device of claim 1 , wherein the first layer comprises a MEMS layer, and wherein the second layer comprises a CMOS layer.

17. The MEMS device of claim 1 , wherein the MEMS device comprises an accelerometer, a gyroscope, a magnetometer, a barometer, a microphone, or an ultrasonic sensor.

18. A method for a microelectromechanical system (MEMS) device, comprising:
coupling a first layer to a second layer with an anchor, the first layer comprising a first plane, the second layer comprising a second plane, wherein the second layer is below the first layer;
positioning a plurality of temperature sensors within the second plane; and
providing one or more switching elements, the one or more switching elements configured to selectively monitor the plurality of temperature sensors, wherein the one or more switching elements selectively combine temperature sensor outputs from a first subset of the plurality of temperature sensors to measure a first temperature characteristic corresponding to the first subset, and wherein the one or more switching elements switch a second subset of the p

Assignees

• Invensense Inc

Inventors

• Dekoninck David
• Kumar Varun Subramaniam
• Thompson Matthew Julian
• Tsinker Vadim
• Jayaraman Logeeswaran Veerayah
• Nitzan Sarah
• Johari-Galle Houri
• Shin Jongwoo
• Jin Le

Classifications

• B81B7/0019 Primary

  Protection against thermal alteration or destruction (B81B7/0083 takes precedence) · CPC title

• B81B7/0087 Primary

  On-device systems and sensors for controlling, regulating or monitoring · CPC title

• G01K1/20

  Compensating for effects of temperature changes other than those to be measured, e.g. changes in ambient temperature · CPC title

• G01L9/0072

  using variations in capacitance · CPC title

• G01L19/04

  Means for compensating for effects of changes of temperature {, i.e. other than electric compensation} · CPC title