MEMS device formed by at least two bonded structural layers and manufacturing process thereof

Patent metadata

Field	Value
Publication number	US-10954121-B2
Application number	US-201916708271-A
Country	US
Kind code	B2
Filing date	Dec 9, 2019
Priority date	Jun 27, 2016
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

A microelectromechanical device having a first substrate of semiconductor material and a second substrate of semiconductor material having a bonding recess delimited by projecting portions, monolithic therewith. The bonding recess forms a closed cavity with the first substrate. A bonding structure is arranged within the closed cavity and is bonded to the first and second substrates. A microelectromechanical structure is formed in a substrate chosen between the first and second substrates. The device is manufactured by forming the bonding recess in a first wafer; depositing a bonding mass in the bonding recess, the bonding mass having a greater depth than the bonding recess; and bonding the two wafers.

First claim

The invention claimed is:

1. A device comprising:
a first body having a first surface, the first body having a suspended microelectromechanical structure and a peripheral structure adjacent to the suspended microelectromechanical structure on the first surface, a first portion of the peripheral structure being spaced apart from the suspended microelectromechanical structure;
a second body having a second surface that faces the first surface of the first body, the second body having a first recess in the second surface;
a closed cavity between the second body and the first portion of the peripheral structure, the closed cavity including the first recess; and
a bonding structure in the closed cavity, the bonding structure coupled between the first and second bodies.

2. The device according to claim 1 , wherein the closed cavity surrounds the suspended microelectromechanical structure.

3. The device according to claim 1 , wherein the second body includes a dielectric layer on the second surface, the bonding structure is coupled to the dielectric layer of the second body.

4. The device according to claim 1 , wherein at least one of the first body and the second body includes a containment trench at the closed cavity.

5. The device according to claim 4 , wherein the containment trench extends from the first recess toward an inside of the second body.

6. The device according to claim 4 , wherein the containment trench is positioned near one or more of an external perimeter and an internal perimeter of the first recess.

7. The device according to claim 1 , wherein the suspended microelectromechanical structure includes one of a micromirror, an inertial sensor, and a pressure sensor.

8. The device according to claim 1 , wherein the first portion of the peripheral structure protrudes toward the second surface of the second body beyond the suspended microelectromechanical structure.

9. The device according to claim 1 , wherein the first portion of the peripheral structure includes at least two semiconductor layers.

10. The device according to claim 9 , wherein the first portion of the peripheral structure includes a dielectric layer between two of the at least two semiconductor layers.

11. The device according to claim 1 , wherein the second body includes a second recess on the second surface and the suspended microelectromechanical structure faces the second recess, the first recess has a first dimension in a first direction, the second recess has a second dimension in the first direction, and the first dimension is smaller than the second dimension.

12. The device according to claim 11 , wherein the suspended microelectromechanical structure includes a suspended platform and a reflecting layer on a first surface of the suspended platform, a second surface of the suspended platform facing the second recess, the second surface opposite to the first surface.

13. A device comprising:
a first body having a first recess and a second recess on a same surface, the second recess including an etch stop layer;
a second body having a microelectromechanical structure at a central portion of the second body and a peripheral structure that is at least partially spaced apart from the microelectromechanical structure, the microelectromechanical structure facing the first recess; and
a bonding structure in the second recess and on the etch stop layer, the bonding structure coupling the first body and the second body together.

14. The device according to claim 13 , wherein the bonding structure is made of a material that compresses in response to a force applied on the material.

15. The device according to claim 13 , wherein the second recess includes a trench, the bonding structure being partially in the trench.

16. The device of claim 15 , wherein the trench is positioned near one or more of an external perimeter and an internal perimeter of the second recess.

17. A device comprising:
a first body having a first recess on a first face of the first body;
a second body having a suspended microelectromechanical structure and a peripheral structure adjacent to the suspended microelectromechanical structure on a second face of the second body, a first portion of the peripheral structure protruding toward the first body beyond the suspended microelectromechanical structure and covering the first recess of the first body, the first portion including at least two semiconductor layers; and
a bonding structure in the first recess, the bonding structure being bonded to the first body and the second body.

18. The device according to claim 17 , wherein the first portion and the first recess form a sealed cavity.

19. The device according to claim 17 , wherein the first body includes a second recess on the first face and the suspended microelectromechanical structure faces the second recess.

20. The device according to claim 17 , wherein the first portion include a first semiconductor layer of the at least two semiconductor layers that covers the first recess, a second semiconductor layer of the at least two semiconductor layers that is substantially at a same level as the suspended microelectromechanical structure, and a dielectric layer between the first semiconductor layer and the second semiconductor layer.

Assignees

• St Microelectronics Srl

Inventors

• Allegato Giorgio
• Oggioni Laura
• Garavaglia Matteo
• Somaschini Roberto

Classifications

• B81C2201/019

  Bonding or gluing multiple substrate layers · CPC title

• B81C2203/019

  characterised by the material or arrangement of seals between parts · CPC title

• B81B2201/0264

  Pressure sensors · CPC title

• B81C1/00269 Primary

  Bonding of solid lids or wafers to the substrate · CPC title

• B81B2203/0315

  Cavities · CPC title