Pressure sensors and method for forming a mems pressure sensor

Patent metadata

Field	Value
Publication number	US-2018335359-A1
Application number	US-201815976111-A
Country	US
Kind code	A1
Filing date	May 10, 2018
Priority date	May 17, 2017
Publication date	Nov 22, 2018
Grant date	—

Abstract

A pressure sensor is provided. The pressure sensor includes at least two electrodes and an integrated circuit configured to sense a capacitance between the at least two electrodes. Further, the pressure sensor includes a Microelectromechanical System (MEMS) structure including a conductive or dielectric membrane configured to move, depending on the pressure, relative to the at least two electrodes.

First claim

What is claimed is:

1 . A pressure sensor comprising:
at least two electrodes; an integrated circuit configured to sense a capacitance between the at least two electrodes; and a microelectromechanical system (MEMS) structure comprising a membrane configured to move, depending on a pressure applied thereto, relative to the at least two electrodes, wherein the membrane is a conductive membrane or a dielectric membrane.

2 . The pressure sensor of claim 1 , wherein the at least two electrodes are separated from the membrane by an evacuated cavity.

3 . The pressure sensor of claim 1 , wherein the at least two electrodes are arranged on a rigid region of the pressure sensor.

4 . The pressure sensor of claim 1 , further comprising:
an integrated circuit die comprising the integrated circuit, wherein the integrated circuit is configured to calculate the pressure based on the sensed capacitance between the at least two electrodes.

5 . The pressure sensor of claim 4 , wherein the integrated circuit die and the MEMS structure are attached to opposite sides of a carrier substrate, and wherein an evacuated cavity is formed between the membrane and the carrier substrate.

6 . The pressure sensor of claim 5 , wherein the at least two electrodes are arranged on a same surface side of the carrier substrate.

7 . The pressure sensor of claim 6 , wherein the integrated circuit is coupled to the at least two electrodes by vias penetrating the carrier substrate.

8 . The pressure sensor of claim 5 , wherein the carrier substrate is made of dielectric material, and wherein the at least two electrodes are arranged within the integrated circuit die and are arranged between semiconductor layers of the integrated circuit and the MEMS structure.

9 . The pressure sensor of claim 8 , wherein the integrated circuit die is glued to the carrier substrate, wherein a first electrode is arranged below a center of the membrane, and wherein a second electrode and a third electrode are arranged on opposite sides of the first electrode and are arranged below rim portions of the MEMS structure carrying the membrane.

10 . The pressure sensor of claim 9 , wherein the integrated circuit is configured to calculate the pressure based on a first capacitance sensed between the second electrode and the third electrode, a second capacitance sensed between the first electrode and the second electrode, and a third capacitance sensed between the first electrode and the third electrode.

11 . The pressure sensor of claim 10 , wherein at least one fourth electrode is arranged between the first electrode and the second electrode or the third electrode, wherein minimum distances of the at least one fourth electrode to the second electrode or to the third electrode are smaller than a minimum distance of the at least one fourth electrode to the first electrode.

12 . The pressure sensor of claim 11 , wherein the integrated circuit is further configured to calculate the pressure based on fourth capacitances sensed between the at least one fourth electrode and one of the second electrode and the third electrode.

13 . The pressure sensor of claim 12 , wherein a sum of the fourth capacitances are at least three times higher than a sum of the second capacitance and the third capacitance when the membrane is in a rest position.

14 . The pressure sensor of claim 4 , wherein the MEMS structure is attached to a surface of the integrated circuit die such that an evacuated cavity is formed between the membrane and the integrated circuit die.

15 . The pressure sensor of claim 14 , wherein a metal layer is formed on at least one of the membrane and a contact surface of the MEMS structure for contacting the integrated circuit die.

16 . The pressure sensor of claim 15 , wherein the metal layer formed on the contact surface of the MEMS structure is one of the at least two electrodes.

17 . The pressure sensor of claim 1 , wherein vertical distances between the membrane and the at least two electrodes are smaller than a distance between the at least two electrodes.

18 . The pressure sensor of claim 14 , wherein the integrated circuit and the MEMS structure are arranged on opposite sides of a semiconductor substrate of the integrated circuit die.

19 . The pressure sensor of claim 18 , wherein the integrated circuit and the at least two electrodes are arranged on opposite sides of the semiconductor substrate, and wherein the integrated circuit is coupled to the at least two electrodes by vias penetrating the integrated circuit die.

20 . The pressure sensor of claim 14 , wherein the integrated circuit is arranged between the MEMS structure and a semiconductor substrate of the integrated circuit die.

21 . The pressure sensor of claim 1 , wherein the MEMS structure is free from electronic components has no electrical connection to the integrated circuit.

22 . A pressure sensor, comprising:
a magnetic sensor element configured to generate a signal based on a magnetic field sensed by the magnetic sensor element; a microelectromechanical system (MEMS) structure comprising a membrane configured to move, depending on a pressure applied thereto, relative to the magnetic sensor element; and a field influencing element configured to modify the magnetic field based on a movement of the membrane, wherein the field influencing element is arranged on the membrane.

23 . The pressure sensor claim 22 , wherein the field influencing element comprises a structure of magnetic material.

24 . The pressure sensor of claim 22 , wherein the field influencing element comprises a conductive structure configured to conduct an electric current.

25 . The pressure sensor of claim 22 , wherein the magnetic sensor element comprises a Hall effect region of polygonal shape, and wherein electrical contacts configured to provide a voltage signal from the Hall effect region or to provide electrical supply signals to the Hall effect region are arranged symmetrically along a periphery of the Hall effect region.

26 . The pressure sensor of claim 22 , further comprising:
a permanent magnetic element, wherein the permanent magnetic element and the field influencing element are arranged on opposite sides of the magnetic sensor element.

27 . The pressure sensor of claim 22 , further comprising:
an integrated circuit configured to calculate the pressure based on the signal.

28 . A method for forming a microelectromechanical system (MEMS) pressure sensor, the method comprising:
providing a first substrate comprising, in a recessed portion, a recess and a membrane shaped by the recess, the membrane comprising at least one field influencing element; providing a second substrate comprising a read-out element and a read-out circuit coupled to the read-out element; and bonding the first substrate to the second substrate such that the recess is hermetically sealed thereby forming a sealed cavity.

29 . The method of claim 28 , wherein, after bonding the first substrate to the second substrate, the first substrate has no electrical connection to the second substrate.

30 . The method of claim 28 , wherein the field influencing element is an electric field influencing element or a magnetic field influencing element.

Assignees

• Infineon Technologies Ag

Inventors

• Eckinger Markus
• Hammerschmidt Dirk
• Brandl Florian
• Winkler Bernhard

Classifications

• B81B2207/012

  the micromechanical device and the control or processing electronics being separate parts in the same package · CPC title

• B81B2203/04

  Electrodes · CPC title

• B81B2201/0264

  Pressure sensors · CPC title

• B81B3/0021

  Transducers for transforming electrical into mechanical energy or vice versa (dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00) · CPC title

• G01L9/0072 Primary

  using variations in capacitance · CPC title