Micromechanical pressure sensor with two cavities and diaphragms and corresponding production method

Patent metadata

Field	Value
Publication number	US-11560302-B2
Application number	US-201816635644-A
Country	US
Kind code	B2
Filing date	Jul 20, 2018
Priority date	Aug 2, 2017
Publication date	Jan 24, 2023
Grant date	Jan 24, 2023

Abstract

In micromechanical pressure sensor device and a corresponding production method, the micromechanical pressure sensor device is provided with a first diaphragm; an adjacent first cavity; a first deformation detection device situated in and/or on the first diaphragm for detecting a deformation of the first diaphragm as a consequence of an applied external pressure change and as a consequence of an internal mechanical deformation of the pressure sensor device; a second diaphragm; an adjacent second cavity; and a second deformation detection device situated in and/or on the second diaphragm for detecting a deformation of the second diaphragm as a consequence of the internal mechanical deformation of the pressure sensor device, where the second diaphragm is developed in such a way that it is not deformable as a consequence of the external pressure change.

First claim

What is claimed is:

1. A micromechanical pressure sensor device comprising:
a first cavity;
a first diaphragm that is adjacent to the first cavity and that is deformable, to produce a deformation of the first diaphragm, by an applied external pressure change and by an internal mechanical deformation of the pressure sensor device;
a first deformation detection device situated in and/or on the first diaphragm, wherein the first deformation detection device is configured to detect the deformation of the first diaphragm;
a second cavity;
a second diaphragm that is adjacent to the second cavity and that is deformable, to produce a deformation of the second diaphragm, by the internal mechanical deformation of the pressure sensor device, but not by the applied external pressure change; and
a second deformation detection device situated in and/or on the second diaphragm, wherein the second deformation detection device is configured to detect the deformation of the second diaphragm,
wherein the first diaphragm and the first cavity are formed in a first micromechanical function layer of the micromechanical pressure sensor device, and the second diaphragm is formed in a second micromechanical function layer of the micromechanical pressure sensor device, the second micromechanical function layer being situated at a distance from the first micromechanical function layer.

2. The micromechanical pressure sensor device of claim 1 , wherein the second micromechanical function layer is situated at one side of the first diaphragm, the first diaphragm is closed, the second diaphragm has a through opening, and the second cavity is situated between the first diaphragm and the second diaphragm and fluidically communicates with the through opening.

3. The micromechanical pressure sensor device of claim 1 , further comprising a spacer layer arranged between the first and second micromechanical function layers.

4. The micromechanical pressure sensor device of claim 1 , further comprising a sealing layer that seals the first cavity on a side of the first micromechanical function layer situated opposite the first diaphragm, such that the second micromechanical function layer is situated on a first side of the sealing layer, wherein the first diaphragm is closed, the second diaphragm has a through opening, and the second cavity is situated between the second diaphragm and the sealing layer and fluidically communicates with the through opening.

5. The micromechanical pressure sensor device of claim 1 , further comprising a cap layer on the first cavity on a side of the first micromechanical function layer situated opposite the first diaphragm, wherein the second micromechanical function layer is situated at one side of the sealing layer, the first diaphragm is closed, the second diaphragm has a first through opening, the second cavity fluidically communicates with the first through opening, and the sealing layer has a second through opening.

6. The micromechanical pressure sensor device of claim 1 , wherein the first deformation detection device and/or the second deformation detection device has one or more piezoresistive elements.

7. A micromechanical pressure sensor device comprising:
a first cavity;
a first diaphragm that is adjacent to the first cavity and that is deformable, to produce a deformation of the first diaphragm, by an applied external pressure change and by an internal mechanical deformation of the pressure sensor device;
a first deformation detection device situated in and/or on the first diaphragm, wherein the first deformation detection device is configured to detect the deformation of the first diaphragm;
a second cavity;
a second diaphragm that is adjacent to the second cavity and that is deformable, to produce a deformation of the second diaphragm, by the internal mechanical deformation of the pressure sensor device, but not by the applied external pressure change; and
a second deformation detection device situated in and/or on the second diaphragm, wherein the second deformation detection device is configured to detect the deformation of the second diaphragm,
wherein:
the first diaphragm and the first cavity are formed in a first micromechanical function layer;
the second diaphragm and the second cavity are formed in the first micromechanical function layer, laterally spaced apart from the first diaphragm and the first cavity; and
the first cavity and the second cavity are sealed on a side of the first micromechanical function layer that lies opposite the first diaphragm and the second diaphragm,

wherein the first diaphragm is closed and the second diaphragm has a through opening.

8. A method for producing a micromechanical pressure sensor device, the method comprising:
arranging a first diaphragm, that is deformable to produce a deformation of the first diaphragm by an applied external pressure change and by an internal mechanical deformation of the pressure sensor device, adjacent to a first cavity;
arranging a first deformation detection device in and/or on the first diaphragm wherein the first deformation detection device is configured to detect the deformation of the first diaphragm;
arranging adjacent to a second cavity a second diaphragm that is deformable to produce a deformation of the second diaphragm by the internal mechanical deformation of the pressure sensor device, but not by the applied external pressure change; and
arranging a second deformation detection device in and/or on the second diaphragm, wherein the second deformation detection device is configured to detect the deformation of the second diaphragm,
wherein the first diaphragm and the first cavity are formed in a first micromechanical function layer of the micromechanical pressure sensor device, and the second diaphragm is formed in a second micromechanical function layer of the micromechanical pressure sensor device, the second micromechanical function layer being situated at a distance from the first micromechanical function layer.

9. A method for producing a micromechanical pressure sensor device, the method comprising:
arranging a first diaphragm, that is deformable to produce a deformation of the first diaphragm by an applied external pressure change and by an internal mechanical deformation of the pressure sensor device, adjacent to a first cavity;
arranging a first deformation detection device in and/or on the first diaphragm wherein the first deformation detection device is configured to detect the deformation of the first diaphragm;
arranging adjacent to a second cavity a second diaphragm that is deformable to produce a deformation of the second diaphragm by the internal mechanical deformation of the pressure sensor device, but not by the applied external pressure change; and
arranging a second deformation detection device in and/or on the second diaphragm, wherein the second deformation detection device is configured to detect the deformation of the second diaphragm,
wherein:
the first diaphragm and the first cavity are formed in a first micromechanical function layer;
the second diaphragm and the second cavity are formed in the first micromechanical function layer, laterally spaced apart from the first diaphragm and the first cavity; and
the first cavity and the second cavity are sealed on a side of the first micromechanical function layer that lies opposite the first diaphragm and the second diaphragm,

wherein the first diaphragm is closed and the second diaphragm has a through opening.

Assignees

• Bosch Gmbh Robert

Inventors

• Heuck Friedjof
• Maul Robert

Classifications

• B81B2201/0264

  Pressure sensors · CPC title

• B81B3/0072 Primary

  For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers · CPC title

• G01L9/008

  using piezoelectric devices (piezoelectric resonators G01L9/0022; surface acoustic waves G01L9/0025) · CPC title

• G01L9/06

  of piezo-resistive devices · CPC title

• G01L13/026 Primary

  involving double diaphragm · CPC title