MICROMACHINED MONOLITHIC 3-AXIS GYROSCOPE WITH SINGLE DRIVE

• US 20160264404A1
• Filed: 01/25/2016
• Published: 09/15/2016
• Est. Priority Date: 09/18/2010
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Semiconductor Corporation (ON Semiconductor Corporation)
• Inventors: Acar, Cenk
• Granted Patent: US 10,050,155 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2203/051 Translation according to an axis parallel to the substrate
• CPC Class Codes: B81B 2203/053 Translation according to an axis perpendicular to the substrate
• CPC Class Codes: B81B 2203/055 Translation in a plane parallel to the substrate, i.e. enabling movement along any direction in the plane
• CPC Class Codes: B81B 2203/056 Rotation in a plane parallel to the substrate
• CPC Class Codes: B81B 2203/058 Rotation out of a plane parallel to the substrate
• CPC Class Codes: B81B 2207/094 Feed-through, via
• CPC Class Codes: B81B 7/04 Networks or arrays of similar microstructural devices
• CPC Class Codes: G01C 19/5755 the devices having a single sensing mass
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 2015/0848 using a plurality of mechanically coupled spring-mass systems, the sensitive direction of each system being different
• CPC Class Codes: H01L 29/84 controllable by variation of applied mechanical force, e.g. of pressure

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.

Claims

1-20. -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 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.

39. The system of claim 38, 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.

40. The system of claim 37, 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; and

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.