MEMS device including a capacitive pressure sensor and manufacturing process thereof

• US 10,689,251 B2
• Filed: 07/25/2019
• Issued: 06/23/2020
• Est. Priority Date: 03/31/2017
• Status: Active Grant

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Duqi, Enri, Baldo, Lorenzo, Carminati, Roberto
• Primary Examiner(s): Kusumakar, Karen
• Assistant Examiner(s): Bowen, Adam S
• Application Number:
  US16/522,301
• Publication Number:
  US 20190345028A1
• Time in Patent Office: 334 Days
• Field of Search: 257415
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2207/097 Interconnects arranged on the substrate or the lid, and covered by the package seal
• 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 1/00222 Integrating an electronic processing unit with a micromechanical structure
• CPC Class Codes: B81C 1/00261 Processes for packaging MEMS devices MEMS packages B81B7/0032, packaging of smart-MEMS B81C1/0023
• CPC Class Codes: B81C 1/00349 Creating layers of material on a substrate
• CPC Class Codes: B81C 2201/01 in or on a substrate

Abstract

MEMS device, in which a body made of semiconductor material contains a chamber, and a first column inside the chamber. A cap of semiconductor material is attached to the body and forms a first membrane, a first cavity and a first channel. The chamber is closed on the side of the cap. The first membrane, the first cavity, the first channel and the first column form a capacitive pressure sensor structure. The first membrane is arranged between the first cavity and the second face, the first channel extends between the first cavity and the first face or between the first cavity and the second face and the first column extends towards the first membrane and forms, along with the first membrane, plates of a first capacitor element.

Claims

1. A MEMS device comprising:

a first semiconductor die including a chamber, the first semiconductor die including a transducer and a column in the chamber; and

a second semiconductor die coupled to the first semiconductor die, a first surface of the second semiconductor die facing the column and forming a membrane, wherein the column and the membrane form plates of a capacitive pressure sensor, and wherein the first surface of the second semiconductor die includes an absorber element facing the transducer.

2. The MEMS device of claim 1, wherein the membrane is formed by a channel formed in a second surface of the second semiconductor die, wherein the channel includes a vertical portion extending from the second surface toward the first surface and a lateral portion that is parallel to the second surface.

3. The MEMS device of claim 1, further comprising an insulating layer between the plates of the capacitive pressure sensor.

4. The MEMS device of claim 3, wherein the insulating layer is on the membrane.

5. The MEMS device of claim 1, wherein the second semiconductor die forms a cap that covers the chamber and encloses the transducer.

6. The MEMS device of claim 1, wherein the transducer is at least one of an accelerometer or a gyroscope.

7. The MEMS device of claim 1, wherein the first and second semiconductor dice are formed from single-crystal silicon.

8. The MEMS device of claim 1, wherein the column is a first column, wherein the first semiconductor die includes a second column in the chamber, wherein the membrane is a first membrane and the capacitive pressure sensor is a first capacitive pressure sensor, wherein the first surface of the second semiconductor die includes a second membrane facing the second column, and wherein the second column and the second membrane form plates of a second capacitive pressure sensor.

9. The MEMS device of claim 8, wherein the first and second columns are on opposing sides of the transducer.

10. The MEMS device of claim 8, wherein the second membrane is formed by a channel formed in the first surface of the second semiconductor die, wherein the channel includes a vertical portion extending from the first surface toward the second surface and a lateral portion that is parallel to the first surface.

11. A MEMS device comprising:

a first semiconductor die including a chamber, the first semiconductor die including a transducer and a column in the chamber; and

a second semiconductor die coupled to the first semiconductor die, wherein a first surface of the second semiconductor die faces the column, wherein a membrane and an absorber element are located at the first surface of the second semiconductor die, wherein the absorber element faces the transducer, and wherein the membrane is formed by a channel formed at the first surface of the second semiconductor die, the column and the membrane forming plates of a capacitive pressure sensor.

12. The MEMS device of claim 11, wherein the transducer is an inertial transducer.

13. The MEMS device of claim 12, wherein the second semiconductor die forms a cap that covers the inertial transducer.

14. The MEMS device of claim 11, wherein the first and second semiconductor dice are formed from single-crystal silicon.

15. The MEMS device of claim 11, wherein the column is a first column, wherein the first semiconductor die includes a second column in the chamber, wherein the membrane is a first membrane and the capacitive pressure sensor is a first capacitive pressure sensor, wherein the first surface of the second semiconductor die includes a second membrane facing the second column, and wherein the second column and the second membrane form plates of a second capacitive pressure sensor.

16. A MEMS device comprising:

a first semiconductor die including a chamber, the first semiconductor die including a transducer and first and second columns in the chamber; and

a second semiconductor die coupled to the first semiconductor die, a first surface of the second semiconductor die facing the first and second columns and forming first and second membranes, respectively, wherein the first column and the first membrane form plates of a first capacitive pressure sensor, wherein the second column and the second membrane form plates of a second capacitive pressure sensor.

17. The MEMS device of claim 16, wherein the first membrane is formed by a first channel extending from a second surface of the second semiconductor die, the first channel including a first portion extending from the second surface toward the first surface and a second portion extending parallel to the first surface, wherein the second membrane is formed by a second channel extending from the first surface of the second semiconductor die, the second channel including a first portion extending from the first surface toward the second surface and a second portion extending parallel to the first surface.

18. The MEMS device of claim 17, wherein the second capacitive pressure sensor is a reference capacitive pressure sensor.

19. The MEMS device of claim 16, wherein the transducer is between the first and second capacitive pressure sensors.

20. The MEMS device of claim 16, wherein the transducer is at least one of an accelerometer or a gyroscope.