Technique for forming a MEMS device

• US 9,260,290 B2
• Filed: 09/24/2014
• Issued: 02/16/2016
• Est. Priority Date: 03/30/2011
• Status: Active Grant

• Current Assignee: Semiconductor Manufacturing International Corporation
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Quevy, Emmanuel P., Low, Carrie W., Hui, Jeremy Ryan, Gu, Zhen
• Primary Examiner(s): MULPURI, SAVITRI
• Application Number:
  US14/494,688
• Publication Number:
  US 20150008545A1
• Time in Patent Office: 510 Days
• Field of Search: 438/50
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2207/015 the micromechanical device and the control or processing electronics being integrated on the same substrate
• CPC Class Codes: B81B 3/0062 Devices moving in two or more dimensions, i.e. having special features which allow movement in more than one dimension
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 2203/0735 Post-CMOS, i.e. forming the micromechanical structure after the CMOS circuit
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure

Abstract

An apparatus is formed on a substrate including at least one semiconductor device. The apparatus includes a microelectromechanical system (MEMS) device comprising at least one of a portion of a first structural layer and a portion of a second structural layer formed above the first structural layer. The second structural layer has a thickness substantially greater than a thickness of the first structural layer. In at least one embodiment, the MEMS device includes a first portion of the second structural layer and a second portion of the second structural layer. In at least one embodiment, the MEMS device further comprises a gap between the first portion of the second structural layer and the second portion of the second structural layer. In at least one embodiment, the gap has a width at least one order of magnitude less than the thickness of the second structural layer.

Claims

1. An apparatus formed on a substrate including at least one semiconductor device, the apparatus comprising:

a microelectromechanical system (MEMS) device comprising a portion of a first structural layer and a portion of a second structural layer formed above the first structural layer, the second structural layer having a thickness greater than a thickness of the first structural layer,

wherein the MEMS device comprises a member comprising the portion of the first structural layer and the portion of the second structural layer,

wherein the portion of the second structural layer is an attachment attached to the first portion of the first structural layer.

2. The apparatus, as recited in claim 1, wherein the portion of the second structural layer increases the mass of the member of the MEMS device formed by the portion of the first structural layer.

3. The apparatus, as recited in claim 1, wherein the MEMS device comprises a first portion of the second structural layer and a second portion of the second structural layer, the MEMS device further comprising:

a gap between the first portion of the second structural layer and the second portion of the second structural layer, the gap having a width at least one order of magnitude less than the thickness of the second structural layer.

4. The apparatus, as recited in claim 3, wherein the first and second portions of the second structural layer form electrically isolated, electrostatically coupled portions of the MEMS device.

5. The apparatus, as recited in claim 1, wherein the MEMS device comprises a first portion of the second structural layer and a second portion of the second structural layer, wherein an electrode of the MEMS device comprises the first portion of the second structural layer and a member of the MEMS device comprises the second portion of the second structural layer.

6. The apparatus, as recited in claim 5, wherein the member is a mass of an inertial sensor.

7. The apparatus, as recited in claim 6, wherein a first portion of the first structural layer forms an anchor for the mass and is electrically coupled to the mass.

8. The apparatus, as recited in claim 1, further comprising:

at least one electrical contact coupling the MEMS device to a semiconductor device of the at least one semiconductor device.

9. The apparatus, as recited in claim 1, wherein the second structural layer has a thickness of at least two times the thickness of the first structural layer.

10. The apparatus, as recited in claim 1, wherein the second structural layer has a thickness of at least five times the thickness of the first structural layer.

11. The apparatus, as recited in claim 1, wherein the second structural layer comprises a plurality of layers of a first thickness of a first material, an interface between a first layer of the plurality of layers and a second layer of the plurality of layers comprising an oxide interface.

12. The apparatus, as recited in claim 1, wherein the portion of the second structural layer is in direct contact with the portion of the first structural layer.

13. The apparatus, as recited in claim 3, wherein the portion of the second structural layer is an attachment attached to the first portion of the first structural layer.

14. The apparatus, as recited in claim 1, wherein the attachment comprises a filler and a coating conforming to the filler.

15. An apparatus comprising:

an electrode of a microelectromechanical system (MEMS) device formed above a substrate including a semiconductor device; and

a member of the MEMS device, the member being formed above the substrate and electrostatically coupled to the electrode, the member including a portion of a first structural layer and a portion of a second structural layer formed above the first structural layer, wherein the portion of the second structural layer has a higher mass than the portion of the first structural layer,

wherein the portion of the second structural layer is an attachment attached to the first portion of the first structural layer.

16. The apparatus, as recited in claim 15, further comprising:

a gap between the electrode and the member, the gap having a width at least one order of magnitude less than the thickness of the second structural portion,

wherein in operation of a microelectromechanical system (MEMS) device including the electrode and the member, the electrode is electrostatically coupled to the member across the gap.

17. The apparatus, as recited in claim 15, wherein the electrode comprises:

a portion of the first structural layer; and

a portion of the second structural layer, the second structural layer having a thickness greater than a thickness of the first structural layer.

18. The apparatus, as recited in claim 15, wherein the attachment comprises a filler and a coating conforming to the filler.

19. The apparatus, as recited in claim 15, wherein the attachment is conjoined with the first portion of the structural layer and the first portion of the structural layer and the attachment are operative to move in unison.