Micromachined monolithic 3-axis gyroscope with single drive

Patent metadata

Field	Value
Publication number	US-2016264404-A1
Application number	US-201615005783-A
Country	US
Kind code	A1
Filing date	Jan 25, 2016
Priority date	Sep 18, 2010
Publication date	Sep 15, 2016
Grant date	—

Abstract

This document discusses, among other things, a cap wafer and a via wafer configured to encapsulate a single proof-mass 3-axis gyroscope formed in an x-y plane of a device layer. The single proof-mass 3-axis gyroscope can include a main proof-mass section suspended about a single, central anchor, the main proof-mass section including a radial portion extending outward towards an edge of the 3-axis gyroscope sensor, a central suspension system configured to suspend the 3-axis gyroscope from the single, central anchor, and a drive electrode including a moving portion and a stationary portion, the moving portion coupled to the radial portion, wherein the drive electrode and the central suspension system are configured to oscillate the 3-axis gyroscope about a z-axis normal to the x-y plane at a drive frequency.

First claim

1 - 20 . (canceled)

21 . An inertial measurement system, comprising:
a device layer including:
a 3-axis gyroscope including a single proof mass formed in an x-y plane of a device layer; and
a 3-axis accelerometer including a single proof mass formed in the x-y plane of the device layer adjacent the 3-axis gyroscope,
wherein the 3-axis gyroscope includes a central suspension configured to suspend the single proof-mass of the 3-axis gyroscope about a single, central gyroscope anchor, and wherein the 3-axis accelerometer including separate x, y, and z-axis flexure bearings configured to suspend a single proof-mass of the 3-axis accelerometer about a single, central accelerometer anchor.

22 . The system of claim 21 , including:
a cap wafer bonded to a first surface of the device layer; and a via wafer bonded to a second surface of the device layer, wherein the cap wafer and the via wafer are configured to encapsulate the 3-axis accelerometer and the 3-axis gyroscope in the same cavity.

23 . The system of claim 21 , including a via wafer bonded to a perimeter of a surface of the device layer, and
wherein the single proof masses of the 3-axis gyroscope and the 3-axis accelerometer are anchored to the via wafer using the single, central gyroscope anchor and the single, central accelerometer anchor.

24 . The system of claim 21 , wherein the 3-axis gyroscope includes:
a drive electrode including a moving portion and a stationary portion, the moving portion coupled to the single proof mass of the 3-axis gyroscope, wherein the drive electrode and the central suspension are configured to oscillate the 3-axis gyroscope about a z-axis normal to the x-y plane at a drive frequency.

25 . The system of claim 21 , wherein the x and y-axis flexure bearings are symmetrical about the single, central accelerometer anchor and the z-axis flexure is not symmetrical about the single, central accelerometer anchor.

26 . The system of claim 21 , wherein the single proof mass of the 3-axis gyroscope includes symmetrical x-axis proof-mass sections configured to move anti-phase along an x-axis of the x-y plane in response to a z-axis angular motion.

27 . The system of claim 26 , wherein the single proof mass of the 3-axis gyroscope includes a z-axis gyroscope coupling flexure bearing configured to couple the x-axis proof mass sections and to resist in-phase motion between the x-axis proof mass sections.

28 . The system of claim 21 , including:
a via wafer bonded to a surface of the device layer, the via wafer including:
x-axis and y-axis gyroscope sense electrodes out-of-plane with the device layer configured to detect x-axis and y-axis angular rotation of the single proof mass of the 3-axis gyroscope; and
z-axis accelerometer sense electrodes out-of-plane with the device layer configured to detect z-axis acceleration of the single proof mass of the 3-axis accelerometer; and
wherein the device layer includes:
x-axis and y-axis accelerometer sense electrodes in-plane with the device layer configured to detect x-axis and y-axis acceleration of the single proof mass of the 3-axis accelerometer; and
z-axis gyroscope sense electrodes in-plane with the device layer configured to detect z-axis angular rotation of the single proof mass of the 3-axis gyroscope.

29 . An inertial measurement system, comprising:
a device layer including:
a 3-axis gyroscope including a single proof mass formed in an x-y plane of a device layer; and
a 3-axis accelerometer including a single proof mass formed in the x-y plane of the device layer adjacent the 3-axis gyroscope;
a cap wafer bonded to a first surface of the device layer; and a via wafer bonded to a second surface of the device layer, wherein the 3-axis gyroscope includes a central suspension configured to suspend the single proof-mass of the 3-axis gyroscope about a single, central gyroscope anchor, wherein the 3-axis accelerometer including separate x, y, and z-axis flexure bearings configured to suspend a single proof-mass of the 3-axis accelerometer about a single, central accelerometer anchor, and wherein the cap wafer and the via wafer are configured to encapsulate the 3-axis accelerometer and the 3-axis gyroscope in the same cavity.

30 . The system of claim 29 , wherein the via wafer is bonded to a perimeter of the second surface of the device layer, and
wherein the single proof masses of the 3-axis gyroscope and the 3-axis accelerometer are anchored to the via wafer using the single, central gyroscope anchor and the single, central accelerometer anchor.

31 . The system of claim 29 , wherein the single proof mass of the 3-axis gyroscope includes symmetrical x-axis proof-mass sections configured to move anti-phase along an x-axis of the x-y plane in response to a z-axis angular motion.

32 . The system of claim 31 , wherein the single proof mass of the 3-axis gyroscope includes a z-axis gyroscope coupling flexure bearing configured to couple the x-axis proof mass sections and to resist in-phase motion between the x-axis proof mass sections.

33 . The system of claim 29 , including:
a via wafer bonded to a surface of the device layer, the via wafer including:
x-axis and y-axis gyroscope sense electrodes out-of-plane with the device layer configured to detect x-axis and y-axis angular rotation of the single proof mass of the 3-axis gyroscope; and
z-axis accelerometer sense electrodes out-of-plane with the device layer configured to detect z-axis acceleration of the single proof mass of the 3-axis accelerometer; and
wherein the device layer includes:
x-axis and y-axis accelerometer sense electrodes in-plane with the device layer configured to detect x-axis and y-axis acceleration of the single proof mass of the 3-axis accelerometer; and
z-axis gyroscope sense electrodes in-plane with the device layer configured to detect z-axis angular rotation of the single proof mass of the 3-axis gyroscope.

34 . The system of claim 29 , wherein the 3-axis gyroscope includes:
a drive electrode including a moving portion and a stationary portion, the moving portion coupled to the single proof mass of the 3-axis gyroscope, wherein the drive electrode and the central suspension are configured to oscillate the 3-axis gyroscope about a z-axis normal to the x-y plane at a drive frequency.

35 . The system of claim 29 , wherein the x and y-axis flexure bearings are symmetrical about the single, central accelerometer anchor and the z-axis flexure is not symmetrical about the single, central accelerometer anchor.

36 . The system of claim 29 , wherein the single proof mass of the 3-axis gyroscope includes symmetrical x-axis proof-mass sections configured to move anti-phase along an x-axis of the x-y plane in response to a z-axis angular motion.

37 . An inertial measurement system, comprising:
a device layer including:
a 3-axis gyroscope including a single proof mass formed in an x-y plane of a device layer; and
a 3-axis accelerometer including a single proof mass formed in the x-y plane of the device layer adjacent the 3-axis gyroscope;
a cap wafer bonded to a first surface of the device layer; and a via wafer bonded to a second surface of the device layer, wherein the cap wafer and the via wafer are configured to encapsulate the 3-axis accelerometer and the 3-axis gyroscope in the same cavity.

38 . The system of claim 37 , wherein the 3-axis gyroscope includes a central suspension configured to suspend the single proof-mass of the 3-axis gyroscope about a single, central gyroscop

Assignees

• Fairchild Semiconductor

Inventors

• Acar Cenk

Classifications

• H10D48/50 Primary

  Devices controlled by mechanical forces, e.g. pressure · CPC title

• B81B2201/0242

  Gyroscopes · CPC title

• G01C19/5755 Primary

  the devices having a single sensing mass · CPC title

• B81B2203/053

  Translation according to an axis perpendicular to the substrate · CPC title

• B81B2203/055

  Translation in a plane parallel to the substrate, i.e. enabling movement along any direction in the plane · CPC title