Micro-electro-mechanical device and manufacturing process thereof

Patent metadata

Field	Value
Publication number	US-10150666-B2
Application number	US-201715602760-A
Country	US
Kind code	B2
Filing date	May 23, 2017
Priority date	Nov 19, 2015
Publication date	Dec 11, 2018
Grant date	Dec 11, 2018

Abstract

A micro-electro-mechanical device formed in a monolithic body of semiconductor material accommodating a first buried cavity; a sensitive region above the first buried cavity; and a second buried cavity extending in the sensitive region. A decoupling trench extends from a first face of the monolithic body as far as the first buried cavity and laterally surrounds the second buried cavity. The decoupling trench separates the sensitive region from a peripheral portion of the monolithic body.

First claim

The invention claimed is:

1. A micro-electro-mechanical device, comprising:
a monolithic body of semiconductor material;
a first buried cavity in the monolithic body of semiconductor material;
a sensitive region in the monolithic body facing the first buried cavity; and
a decoupling trench extending into the monolithic body as far as the first buried cavity, the decoupling trench decoupling the sensitive region from a peripheral portion of the monolithic body and forming the sensitive region.

2. The device according to claim 1 , wherein the monolithic body includes a second buried cavity in the sensitive region, the second buried cavity overlapping the first buried cavity.

3. The device according to claim 1 , further comprising a membrane over the sensitive region, the membrane having a perimeter that is coupled to the sensitive region.

4. The device according to claim 3 , wherein the membrane is spaced apart from the sensitive region by a cavity.

5. The device according to claim 1 , wherein the decoupling trench has a spiral shape that extends around an entire perimeter of the sensitive region.

6. The device according to claim 5 , wherein the decoupling trench has a first end portion and a second end portion, the first end portion and the second end portion extending along a same side of the sensitive region.

7. The device according to claim 1 , further comprising a cap element coupled to a surface of the peripheral portion of the monolithic body.

8. A micro-electro-mechanical device, comprising:
a monolithic body of semiconductor material;
a buried cavity in the monolithic body of semiconductor material;
a sensitive region in the monolithic body covering the buried cavity; and
a movable element including a central portion and a perimeter portion, the perimeter portion coupled to the sensitive region, the central portion of the movable element being separated from the sensitive region by a second cavity.

9. The device according to claim 8 , wherein the movable element is a MEMS inertial sensor that moves in response to acceleration.

10. The device according to claim 8 , comprising a decoupling trench having a spiral shape that separates the sensitive region from a peripheral portion of the monolithic body.

11. The device according to claim 10 , wherein the decoupling trench has a first end portion and a second end portion, the first end portion and the second end portion extending along a same side of the sensitive region.

12. The device according to claim 10 , comprising a cap coupled to the peripheral portion of the monolithic body, the cap forming a cavity with the monolithic body, the movable element being located in the cavity.

13. The device according to claim 8 , wherein monolithic body includes a through opening that places the buried cavity in fluid communication with an environment that is external to the micro-electro-mechanical device.

14. An electronic apparatus comprising:
a microprocessor; and
a micro-electro-mechanical device including:
a monolithic body of semiconductor material;
a buried cavity in the monolithic body of semiconductor material;
a sensitive region in the monolithic body facing the buried cavity; and
a decoupling trench extending into the monolithic body as far as the buried cavity, the decoupling trench decoupling the sensitive region from a peripheral portion of the monolithic body and forming the sensitive region.

15. The electronic device according to claim 14 , wherein the electronic apparatus is at least one of a sphygmomanometer, a household apparatus, a mobile phone, a personal digital assistant, a notebook, and a pressure measuring apparatus.

16. The electronic device according to claim 14 , wherein the cap is coupled to the first face of the monolithic body and integrates an application-specific integrated circuit.

17. The electronic device according to claim 14 , wherein the cap is coupled to the second face of the monolithic body and integrates an application-specific integrated circuit.

18. The electronic device according to claim 17 , wherein the monolithic body includes a through hole at the second face that places the buried cavity in fluid communication with an environment that is external to the micro-electro-mechanical device.

Assignees

• St Microelectronics Srl

Inventors

• Baldo Lorenzo
• Duqi Enri
• Villa Flavio Francesco

Classifications

• B81B2203/0127

  Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function · CPC title

• B81C2203/0785

  Transfer and j oin technology, i.e. forming the electronic processing unit and the micromechanical structure on separate substrates and joining the substrates · CPC title

• G02B26/0858

  the reflecting means being moved or deformed by piezoelectric means · CPC title

• B81B2201/02

  Sensors · CPC title

• B81B7/0009

  Structural features, others than packages, for protecting a device against environmental influences (B81C1/00777 takes precedence) · CPC title