Micromechanical pressure sensor device and corresponding manufacturing method

Patent metadata

Field	Value
Publication number	US-11441964-B2
Application number	US-201816761604-A
Country	US
Kind code	B2
Filing date	Oct 26, 2018
Priority date	Nov 15, 2017
Publication date	Sep 13, 2022
Grant date	Sep 13, 2022

Abstract

A micromechanical pressure sensor device is equipped with a sensor substrate including a front side and a rear side. The device includes a pressure sensor unit suspended in the sensor substrate, a first cavity above the pressure sensor unit, which is exposed toward the front side via one or multiple access openings, one or multiple stress relief trenches, which laterally enclose the pressure sensor unit and form a fluidic connection from the rear side to the first cavity, and a circuit substrate, on which the rear side of the sensor substrate is bonded. A second cavity, which is in fluidic connection with the stress relief trenches, is formed below the pressure sensor unit in the circuit substrate. At least one channel is provided in a periphery of the pressure sensor unit, which is in fluidic connection with the second cavity and is exposed to the outside.

First claim

The invention claimed is:

1. A micromechanical pressure sensor device, comprising:
a sensor substrate including a front side and a rear side;
a pressure sensor unit suspended in the sensor substrate;
a first cavity situated above the pressure sensor unit, the first cavity being exposed toward the front side via one or multiple access openings;
one or multiple stress relief trenches which laterally enclose the pressure sensor unit and form a fluidic connection from the rear side to the first cavity;
a circuit substrate on which the rear side of the sensor substrate is bonded;
a second cavity, which is in fluidic connection with the stress relief trenches, is situated below the pressure sensor unit in the circuit substrate; and
at least one channel, which is in fluidic connection with the second cavity and is exposed to the outside, is situated in a periphery of the pressure sensor unit;
wherein the circuit substrate includes a strip conductor unit, the strip conductor unit including a plurality of strip conductor levels and interposed insulation layers, and the second cavity is situated in the strip conductor unit.

2. The micromechanical pressure sensor device as recited in claim 1 , wherein the channel, the second cavity, the stress relief trenches, and the first cavity, are filled using a passivation medium.

3. The micromechanical pressure sensor device as recited in claim 1 , wherein the sensor substrate and the circuit substrate are at least partially enclosed by a mold housing, which includes a first through opening, which exposes the channel and the access openings.

4. The micromechanical pressure sensor device as recited in claim 1 , wherein the sensor substrate and the circuit substrate are at least partially enclosed by a mold housing, which includes a first through opening, which exposes the access openings, and which includes a second through opening, which exposes the channel.

5. The micromechanical pressure sensor device as recited in claim 3 , wherein a mounting flange is molded into the mold housing or is adhesively bonded onto the mold housing on a side of the mold housing facing away from the sensor substrate.

6. The micromechanical pressure sensor device as recited in claim 3 , wherein the pressure sensor unit includes a third cavity, which is hermetically sealed and which adjoins a diaphragm area, on which or in which a piezoelectric unit is situated for detecting the pressure via a deformation of the diaphragm area.

7. The micromechanical pressure sensor device as recited in claim 3 , wherein the pressure sensor unit is suspended via strip conductors in the sensor substrate.

8. A method for manufacturing a micromechanical pressure sensor device, comprising the following steps:
providing a sensor substrate having a front side and a rear side;
forming a pressure sensor unit suspended in the sensor substrate;
forming a first cavity above the pressure sensor unit, which is exposed via one or multiple access openings to the front side;
forming one or multiple stress relief trenches, which laterally enclose the pressure sensor unit and form a fluidic connection from the rear side to the first cavity;
bonding a circuit substrate including a strip conductor unit on the rear side of the sensor substrate, the strip conductor unit including a plurality of strip conductor levels and interposed insulation layers;
forming a second cavity below the pressure sensor unit in the circuit substrate in the strip conductor unit, the second cavity being in fluidic connection with the stress relief trenches;
forming at least one channel, in a periphery of the pressure sensor unit, which extends from the front side to the rear side and which is in fluidic connection with the second cavity.

9. The method as recited in claim 8 , wherein the channel, the second cavity, the stress relief trenches, and the first cavity, are filled using a passivation medium.

Assignees

• Bosch Gmbh Robert

Inventors

• Senz Volkmar
• Dannenberg Arne
• Franz Jochen

Classifications

• G01L19/0038

  being part of the housing (other details about the housing G01L19/14) · CPC title

• G01L9/0045 Primary

  Diaphragm associated with a buried cavity · CPC title

• G01L19/146 Primary

  using flexible element between the transducer and the support · CPC title

• G01L19/0627

  Protection against aggressive medium in general · CPC title

• G01L9/008

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