Method and apparatus for the monolithic encapsulation of a micro-scale inertial navigation sensor suite

• US 10,308,505 B1
• Filed: 08/11/2014
• Issued: 06/04/2019
• Est. Priority Date: 08/11/2014
• Status: Active Grant

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Kirby, Deborah J., Perahia, Raviv, Nguyen, Hung, Stratton, Frederic P., Chang, David T.
• Primary Examiner(s): Armand, Marc Anthony
• Assistant Examiner(s): Brasfield, Quinton A
• Application Number:
  US14/456,808
• Time in Patent Office: 1,758 Days
• Field of Search: None
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2207/012 the micromechanical device and the control or processing electronics being separate parts in the same package
• CPC Class Codes: B81B 3/00 Devices comprising flexible or deformable elements, e.g. comprising elastic tongues or membranes B81B5/00 takes precedence
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: B81C 1/00285 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: B81C 2203/0172 Seals
• CPC Class Codes: G01C 19/5783 Mountings or housings not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
• CPC Class Codes: G01C 21/18 Stabilised platforms, e.g. by gyroscope

Abstract

A device preferably for use in an inertial navigation system the device having a single IC wafer; a plurality of sensors bonded to bond regions on said single IC wafer, at least one of said bond regions including an opening therein in gaseous communication with a pressure chamber associated with at least one of the plurality of said sensors; and a plurality of caps encapsulating said plurality of sensors, at least one of said plurality of caps forming at least a portion of said pressure chamber. A method of making the device is also disclosed.

Claims

1. An apparatus comprising a sensor suite comprising several sensors each having quartz members formed of quartz from a common body of quartz material;

said sensors being disposed on a single wafer and where each sensor is sealed in a distinct pressure and/or a distinct gaseous environment, the sensor suite further comprising a plurality of cap wafers sealing said sensors in said distinct pressure and/or gaseous environments, at least two of said cap wafers overlapping other ones of said cap wafers; and

a vibration damping unit adhered to at least one of said caps in said plurality of caps.

2. The apparatus of claim 1 wherein each of said cap wafers has a depending sidewall which surrounds at least one of said sensors and which is bonded to said single wafer to thereby hermetically seal said at least one of said sensors.

3. The apparatus of claim 1 further including a gyroscope adhered to a side of said vibration damping unit remote from said plurality of caps.

4. The apparatus of claim 1 wherein at least one of said cap wafers has a depending sidewall which surrounds one of said sensors and which is bonded to said single wafer to thereby hermetically seal said one of said sensors.

5. The apparatus of claim 4 wherein at least another one of said cap wafers has a depending sidewall which at least partially surrounds another one of said sensors, the depending sidewall of said at least another one of said cap wafers has an opening therein for venting at least a portion of said another one of said sensors to ambient.

6. A device comprising:

a single IC wafer;

a plurality of sensors bonded to bond regions on said single IC wafer, at least one of said bond regions including an opening therein in gaseous communication with a pressure chamber associated with at least one of the plurality of said sensors;

a plurality of caps hermetically encapsulating all or at least a portion of said plurality of sensors, at least one of said plurality of caps forming at least a portion of said pressure chamber; and

a monolithic vibration damping unit adhered to at least one of said caps in said plurality of caps.

7. The device of claim 6 wherein a majority of said cap wafers are disposed in an overlapping relationship with one or more other ones of said cap wafers.

8. A device comprising:

a single IC wafer;

a plurality of sensors bonded to bond regions on said single IC wafer;

a plurality of caps hermetically encapsulating all or at least a portion of said plurality of sensors, at least one of said plurality of caps forming at least a portion of a pressure chamber; and

a damping unit adhered to at least one of said plurality of caps.

9. The device of claim 8 further including a gyroscope disposed on a side of said damping unit remote from said caps.

10. The device of claim 8 wherein:

(a) said vibration damping unit is a monolithic vibration damping unit;

(b) one of said encapsulating caps encapsulates (i) one or more of said sensors and/or devices and (ii) another one or ones of said encapsulating caps in a separate fluid or vacuum environment remote from said plurality of caps; and

(c) said monolithic vibration damping unit is disposed on said one of said encapsulating caps.

11. The device of claim 8 wherein said damping unit comprises a squeezed film.

12. The device of claim 11 wherein said plurality of caps are adhered to additional bond regions on said single IC wafer at least one of said additional bond regions includes an opening therein in gaseous communication with said pressure chamber which is associated with at least one of the plurality of said sensors.

13. The device of claim 12 wherein said at least one of said sensors is associated with said bond regions having an opening therein is a pressure detecting device in fluid communication with said opening and wherein the remaining ones of said sensors are selected from the group consisting:

magnetometers, accelerometers and resonators.

14. The device of claim 12 wherein said sensors are formed from a common wafer of quartz.

15. The device of claim 14 wherein all of said sensors have a common crystallographic orientation based on the common wafer of quartz from which they are formed.

16. A device comprising:

a. an integrated circuit chip or wafer;

b. a plurality of sensors and/or devices disposed on said integrated circuit chip or wafer;

c. a plurality of encapsulating caps disposed over said sensors and/or devices, each of said plurality of encapsulating caps being affixed directly to said integrated circuit chip or wafer and encapsulating one or more of said sensors and/or devices with a separate fluid or vacuum environment;

d. a damping material adhered on one side thereof to at least one of said plurality of encapsulating caps; and

e. a gyroscope adhered to another side of said damping material.

17. The device of claim 16 wherein each and every one of said sensors and/or devices is at least partially encapsulated with a unique gaseous pressure and/or a unique gaseous material.

18. The device of claim 16 wherein at least one of said sensors and/or devices is encapsulated with a unique gaseous pressure and/or a unique gaseous material compared with other ones of said sensors and/or devices.

19. The device of claim 16 wherein a vibration damping unit is bonded to at least one of said caps and wherein an accelerometer is disposed on a side of said vibration damping unit spaced from said at least one of said caps.

20. The device of claim 16 wherein said sensors and/or devices are formed from a quartz wafer.

21. The device of claim 16 wherein each of said encapsulating caps has a depending sidewall which surrounds at least one of said plurality of sensors and which is bonded to said integrated circuit chip or wafer to thereby hermetically seal said at least one of said plurality of sensors.

22. The device of claim 16 wherein at least one of said encapsulating caps encapsulates (i) one or more of said sensors and/or devices and (ii) another one or ones of said encapsulating caps in a separate fluid or vacuum environment.

23. The device of claim 16 wherein at least one of said encapsulating caps has a depending sidewall which surrounds one of said plurality of sensors and which is bonded to said integrated circuit chip or wafer to thereby hermetically seal said one of said plurality of sensors.

24. The apparatus of claim 23 wherein at least another one of said encapsulating caps has a depending sidewall which at least partially surrounds another one of said plurality of sensors, the depending sidewall of said at least another one of said encapsulating caps has an opening therein for venting at least a portion of said another one of said plurality of sensors to ambient.

25. A device comprising:

a. an integrated circuit chip or wafer;

b. a plurality of sensors and/or devices disposed on said integrated circuit chip or wafer;

c. encapsulating caps disposed over said sensors and/or devices, each encapsulating cap encapsulating one or more of said sensors and/or devices with a separate fluid or vacuum environment for each of said plurality of sensors and/or devices;

d. a vibration damping unit adhered to each of said plurality of caps;

wherein exposed surfaces of said sensors and/or devices are affixed to bond regions on said integrated circuit chip or wafer and wherein at least one of said bond regions has a opening therein which helps form a fluid communication passage associated with a given one of said sensor or devices, the given one of said sensor or devices comprising a pressure detector, the pressure detector confronting two chambers for measuring a differential pressure across said two chambers, said fluid communication channel being in fluid communication with one of said two chambers.

26. An apparatus comprising a sensor suite in which a plurality of sensors are disposed on a single substrate and wherein said sensors are sealed in distinct pressure and/or a distinct gaseous environments by means of a plurality of caps, each of said plurality of caps being affixed to said single substrate and sealing one or more of said plurality of sensors in said distinct pressure and/or gaseous environment and a silicon wafer containing a vibration damping unit bonded to at least one of said plurality of caps.

27. The apparatus of claim 26 wherein at least one of said caps seals one or more of said sensors and/or devices and also seals another one or ones of said caps in a common separate fluid or vacuum environment.