Micromechanical pressure sensor device and corresponding manufacturing method

• US 9,958,348 B2
• Filed: 11/17/2014
• Issued: 05/01/2018
• Est. Priority Date: 01/14/2014
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Classen, Johannes, Reinmuth, Jochen, Kaelberer, Arnd
• Primary Examiner(s): Shah, Manish S
• Assistant Examiner(s): PLUMB, NIGEL H
• Application Number:
  US15/110,261
• Publication Number:
  US 20160327446A1
• Time in Patent Office: 1,261 Days
• Field of Search: 73723, 73717, 73716, 73715, 73700, 73753
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2207/012 the micromechanical device and the control or processing electronics being separate parts in the same package
• CPC Class Codes: B81B 7/0048 between the MEMS die and the substrate
• CPC Class Codes: G01L 13/026 involving double diaphragm
• CPC Class Codes: G01L 19/0636 using particle filters
• CPC Class Codes: G01L 9/0041 Transmitting or indicating the displacement of flexible diaphragms
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm

Abstract

A micromechanical pressure sensor device and a corresponding manufacturing method. The micromechanical pressure sensor device includes an ASIC wafer having a front side and a rear side, and a rewiring system, formed on the front side of the ASIC wafer, which includes a plurality of stacked strip conductor levels and insulation layers. The pressure sensor device also includes a MEMS wafer having a front side and a rear side, a first micromechanical functional layer which is formed above the front side of the MEMS wafer, and a second micromechanical functional layer which is formed above the first micromechanical functional layer.

Claims

1. A micromechanical pressure sensor device, comprising:

an ASIC wafer having a front side and a rear side;

a rewiring system, formed on the front side of the ASIC wafer, which includes a plurality of stacked strip conductor levels and insulation layers;

a MEMS wafer having a front side and a rear side;

a first micromechanical functional layer which is formed above the front side of the MEMS wafer;

a second micromechanical functional layer which is formed above the first micromechanical functional layer;

a diaphragm area which may be acted on by pressure through a via in the MEMS wafer being formed as a deflectable first pressure detection electrode in one of the first and second micromechanical functional layers; and

a stationary second pressure detection electrode formed in the other of the first and second micromechanical functional layers, at a distance and opposite from the diaphragm area;

wherein the second micromechanical functional layer is connected to the rewiring system by way of a bond connection in such a way that the stationary second pressure detection electrode is enclosed in a cavity, the rewiring system capping the cavity to enclose the stationary second pressure detection electrode;

wherein the diaphragm area is formed in the first micromechanical functional layer, and the stationary second pressure detection electrode is formed in the second micromechanical functional layer; and

wherein the stationary second pressure detection electrode has at least one anchoring area, which is anchored on the first micromechanical functional layer, the second micromechanical functional layer having a contact area separated from the anchoring area, which is anchored on the first micromechanical functional layer and has an electrical connection to an uppermost strip conductor level of the stacked strip conductor levels of the rewiring system by way of an area of the bond connection, and the anchoring area of the stationary second pressure detection electrode and the contact area of the second mechanical functional layer being electrically connected to each other by way of the first micromechanical functional layer.

2. The micromechanical pressure sensor device as recited in claim 1, wherein a spring element is provided between the at least one anchoring area and the remaining portion of the stationary second pressure detection electrode.

3. The micromechanical pressure sensor device as recited in claim 1, wherein a ring-shaped anchoring area is provided.

6. The micromechanical pressure sensor device as recited in claim 1, wherein a reference diaphragm area is formed in the first micromechanical functional layer, and a stationary reference electrode is formed in the second micromechanical functional layer, at a distance and opposite from the reference diaphragm area, and where the reference diaphragm area cannot be acted on by the pressure.

7. The micromechanical pressure sensor device as recited in claim 1, wherein a further diaphragm area is formed in the first micromechanical functional layer, and a stationary reference electrode is formed in the second micromechanical functional layer, at a distance and opposite from the further diaphragm area, the further diaphragm area being designed as a deflectable moisture detection electrode which is covered with a moisture-sensitive layer which may be acted on by moisture through a further via in the MEMS wafer.

8. The micromechanical pressure sensor device as recited in claim 1, wherein a further sensor device is formed in the second micromechanical functional layer, and the bond connection includes an area that is connected to the rewiring system in such a way that the further sensor device is enclosed in a further cavity which is hermetically separated from the cavity.

9. The micromechanical pressure sensor device as recited in claim 1, wherein the diaphragm area may be acted on by counterpressure through a further via in the MEMS wafer which leads into the cavity.

4. A micromechanical sensor device, comprising:

an ASIC wafer having a front side and a rear side;

a rewiring system, formed on the front side of the ASIC wafer, which includes a plurality of stacked strip conductor levels and insulation layers;

a MEMS wafer having a front side and a rear side;

a first micromechanical functional layer which is formed above the front side of the MEMS wafer;

a second micromechanical functional layer which is formed above the second micromechanical functional layer;

a diaphragm area which may be acted on by pressure through a via in the MEMS wafer, the diaphragm area being formed as a deflectable first pressure detection electrode in one of the first and second micromechanical functional layers; and

a stationary second pressure detection electrode formed in the other of the first and second micromechanical functional layer, at a distance and opposite from the diaphragm area;

wherein the second micromechanical functional layer is connected to the rewiring system by way of a bond connection in such a way that the diaphragm area is enclosed in a cavity, the rewiring system capping the cavity to enclose the diaphragm area;

wherein the diaphragm area is formed in the second micromechanical functional layer, and the stationary second pressure detection electrode is formed in the first micromechanical functional layer in a perforated manner;

wherein the diaphragm area is being anchored by way of an anchoring area on the first micromechanical functional layer with a ring-shaped closure;

wherein the second micromechanical functional layer has a contact area separated from the anchoring area, which is anchored on the first micromechanical functional layer and has an electrical connection to an uppermost strip conductor level of the stacked strip conductor levels of the rewiring system by way of an area of the bond connection, and the anchoring area of the diaphragm area and the contact area of the second mechanical functional layer being electrically connected to each other by way of the first micromechanical functional layer.

5. The micromechanical pressure sensor device as recited in claim 4, wherein a stationary third pressure detection electrode is formed in the uppermost strip conductor level, at a distance and opposite from the diaphragm area.

10. A manufacturing method for a micromechanical pressure sensor device, comprising:

providing an ASIC wafer, having a front side and a rear side, and a rewiring system which is formed on the front side of the ASIC wafer and which includes a plurality of strip conductor levels and insulating layers situated in between;

providing a MEMS wafer, having a front side and a rear side, a first micromechanical functional layer which is formed above the front side of the MEMS wafer, and a second micromechanical functional layer which is formed above the first micromechanical functional layer, a diaphragm area which may be acted on by pressure through a via in the MEMS wafer being formed as a deflectable first pressure detection electrode in one of the first and second micromechanical functional layers, and a stationary second pressure detection electrode being formed in the other of the first and second micromechanical functional layers, at a distance and opposite from the diaphragm area; and

connecting the second micromechanical functional layer to the rewiring system by way of a bond connection in such a way that the stationary second pressure detection electrode is enclosed in a cavity, the rewiring system capping the cavity to enclose the stationary second pressure detection electrode;

wherein the diaphragm area is formed in the first micromechanical functional layer, and the stationary second pressure detection electrode is formed in the second micromechanical functional layer;

wherein the stationary second pressure detection electrode having at least one anchoring area, which is anchored on the first micromechanical functional layer;

wherein the second micromechanical functional layer has a contact area separated from the anchoring area, which is anchored on the first micromechanical functional area and has an electrical connection to an uppermost strip conductor level of the stacked strip conductor levels of the rewiring system by way of an area of the bond connection; and

wherein the anchoring area of the stationary second pressure detection electrode and the contact area of the second mechanical functional layer are electrically connected to each other by way of the first micromechanical functional layer.

11. A manufacturing method for a micromechanical pressure sensor device, comprising:

providing an ASIC wafer, having a front side and a rear side, and a rewiring system which is formed on the front side of the ASIC wafer and which includes a plurality of strip conductor levels and insulating layers situated in between;

providing a MEMS wafer, having a front side and a rear side, a first micromechanical functional layer which is formed above the front side of the MEMS wafer, and a second micromechanical functional layer which is formed above the first micromechanical functional layer, a diaphragm area which may be acted on by pressure through a via in the MEMS wafer being formed as a deflectable first pressure detection electrode in one of the first and second micromechanical functional layers, and a stationary second pressure detection electrode being formed in the other of the first and second micromechanical functional layers, at a distance and opposite from the diaphragm area; and

connecting the second micromechanical functional layer to the rewiring system by way of a bond connection in such a way that the diaphragm area is enclosed in a cavity, the rewiring system capping the cavity to enclose the diaphragm area;

wherein the diaphragm area is formed in the second micromechanical functional layer, and the stationary second pressure detection electrode is formed in the first micromechanical functional layer in a perforated manner;

wherein the diaphragm area is anchored by way of an anchoring area on the first micromechanical functional layer with a ring-shaped closure;

wherein the second micromechanical functional layer has a contact area separated from the anchoring area, which is anchored on the first micromechanical functional area and has an electrical connection to an uppermost strip conductor level of the stacked strip conductor levels of the rewiring system by way of an area of the bond connection; and

wherein the anchoring area of the diaphragm area and the contact area of the second mechanical functional layer are electrically connected to each other by way of the first micromechanical functional layer.