Systems and methods for a four-layer chip-scale MEMS device

• US 8,748,206 B2
• Filed: 11/14/2011
• Issued: 06/10/2014
• Est. Priority Date: 11/23/2010
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Horning, Robert D.
• Primary Examiner(s): Kraig, William F
• Assistant Examiner(s): Nicely, Joseph C
• Application Number:
  US13/295,273
• Publication Number:
  US 20120126348A1
• Time in Patent Office: 939 Days
• Field of Search: 257/417, 257/E29.324, 438/50, 438/51, 438/458
• US Class Current: 438/51
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2201/025 Inertial sensors not provided for in B81B2201/0235 - B81B2201/0242
• CPC Class Codes: B81B 2207/095 through the lid
• CPC Class Codes: B81B 2207/096 through the substrate
• CPC Class Codes: B81B 7/0041 maintaining a controlled atmosphere with techniques not provided for in B81B7/0038
• 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 2201/019 Bonding or gluing multiple substrate layers
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/1461 MEMS

Abstract

Systems and methods for a micro-electromechanical system (MEMS) apparatus are provided. In one embodiment, a system comprises a first double chip that includes a first base layer; a first device layer bonded to the first base layer, the first device layer comprising a first set of MEMS devices; and a first top layer bonded to the first device layer, wherein the first set of MEMS devices is hermetically isolated. The system also comprises a second double chip that includes a second base layer; a second device layer bonded to the second base layer, the second device layer comprising a second set of MEMS devices; and a second top layer bonded to the second device layer, wherein the second set of MEMS devices is hermetically isolated, wherein a first top surface of the first top layer is bonded to a second top surface of the second top layer.

Claims

1. A micro-electromechanical system (MEMS) apparatus, the apparatus comprising:

a first double chip comprising;

a first base layer;

a first device layer bonded to the first base layer, the first device layer comprising a first set of MEMS devices; and

a first top layer bonded to the first device layer, wherein the first set of MEMS devices is hermetically isolated; and

a second double chip comprising;

a second base layer;

a second device layer bonded to the second base layer, the second device layer comprising a second set of MEMS devices; and

a second top layer bonded to the second device layer, wherein the second set of MEMS devices is hermetically isolated,

a getter, hermetically sealed between the first double chip and the second double chip, the getter configured to absorb air within the MEMS apparatus, the getter being exposed to air that circulates around at least one of the first set of MEMS devices and the second set of MEMS devices;

wherein a first top surface of the first top layer is bonded to a second top surface of the second top layer.

2. The apparatus of claim 1, wherein the first set of MEMS devices comprises a set of accelerometers, wherein the set of accelerometers senses acceleration along three orthogonal axes.

3. The apparatus of claim 2, wherein the set of accelerometers are hermetically sealed in a gaseous atmosphere type.

4. The apparatus of claim 1, wherein the second set of MEMS devices comprises a set of gyroscopes, wherein the set of gyroscopes senses rotation about three orthogonal axes.

5. The apparatus of claim 4, wherein the set of gyroscopes are hermetically sealed in a vacuum.

6. The apparatus of claim 5, further comprising a channel in the second top layer, wherein the channel allows gas to circulate between the getter and the second device layer.

7. The apparatus of claim 6, wherein the getter is located within a recess formed on the first top surface of the first top layer.

8. The apparatus of claim 1, wherein the first device layer includes a combination of gyroscopes and accelerometers.

9. The apparatus of claim 8, wherein the first device layer comprises a first sealed compartment and a second sealed compartment, wherein the first sealed compartment contains the gyroscopes hermetically sealed in a vacuum, and the second sealed compartment contains accelerometers hermetically sealed within a gaseous atmosphere type.

10. The apparatus of claim 9, further comprising a channel in the first top layer, wherein the channel allows gas to circulate between the getter and the first sealed compartment.

11. The apparatus of claim 1, further comprising vias that provide electrical connections between the first set of MEMS devices and the second set of MEMS devices and an external surface of the MEMS device.

12. The apparatus of claim 11, wherein the vias are formed using at least one of silicon and metal.

13. The apparatus of claim 11, wherein the vias are connected to interconnects, wherein the interconnects allow the first double chip and the second double chip to be electrically mounted on a surface in a plurality of positions.

14. A method for fabricating a micro-electromechanical system (MEMS) device, the method comprising:

forming a first double chip by forming a first base layer, bonding a first device layer containing a first set of MEMS devices to the first base layer, and bonding a first top layer to the first device layer, wherein the first set of MEMS devices are hermetically sealed between the first base layer and the first top layer;

forming a second double chip by forming a second base layer, bonding a second device layer containing a second set of MEMS devices to the second base layer, and bonding a second top layer to the second device layer, wherein the second set of MEMS devices are hermetically sealed between the second base layer and the second top layer; and

hermetically sealing a getter between the first double chip and the second double chip, the getter configured to absorb air within the MEMS device, the getter being exposed to air that circulates around at least one of the first set of MEMS devices and the second set of MEMS devices

bonding the first top layer to the second top layer.

15. The method of claim 14, wherein the first set of MEMS devices comprises a first combination of accelerometers and gyroscopes and the second set of MEMS devices comprises a second combination of accelerometers and gyroscopes, wherein accelerometers in the first combination of accelerometers and gyroscopes and in the second combination of accelerometers and gyroscopes sense acceleration along three orthogonal axes and gyroscopes in the first combination of accelerometers and gyroscopes and in the second combination of accelerometers and gyroscopes sense rotation about three orthogonal axes.

16. The method of claim 15, further comprising hermetically sealing the accelerometers in a gaseous atmosphere type.

17. The method of claim 15, further comprising hermetically sealing the gyroscopes in a vacuum.

18. The method of claim 14, further comprising:

forming a channel in at least one of the first top layer and the second top layer, wherein the channel allows gas to circulate between the getter and at least one of the first device layer and the second device layer.

19. The method of claim 14, further comprising:

forming a plurality of MEMS devices in a plurality of joined wafers; and

singulating the plurality of MEMS devices into individual MEMS devices.

20. An inertial measurement unit (IMU) device, the device comprising:

a first double chip comprising;

a first glass base layer;

a first semiconductor layer bonded to the first glass base layer, the first semiconductor layer comprising a first set of MEMS gyroscopes and MEMS accelerometers; and

a first glass top layer bonded to the first semiconductor layer; and

a second double chip comprising;

a second glass base layer;

a second semiconductor layer bonded to the second base layer, the second semiconductor layer comprising a second set of MEMS gyroscopes and MEMS accelerometers such that the combination of the first set of MEMS gyroscopes and MEMS accelerometers and the second set of MEMS gyroscopes and MEMS accelerometers provides measurements of acceleration along, and rotation about, three orthogonal axes; and

a second glass top layer bonded to the second semiconductor layer;

a getter hermetically sealed between the first double chip and the second double chip, the getter configured to absorb air within the IMU device, the getter being exposed to air that circulates around at least one of the first semiconductor layer and the second semiconductor layer;

wherein the second glass top layer is bonded to the first glass top layer.