Pressure sensor

• US 9,958,349 B2
• Filed: 03/30/2016
• Issued: 05/01/2018
• Est. Priority Date: 04/02/2015
• Status: Active Grant

• Current Assignee: InvenSense International, LLC
• Original Assignee: Invensense Incorporated (TDK Corporation)
• Inventors: Schumm, Johannes, Reinhard, Andreas, Kraehenbuehl, Thomas, Thiele, Stefan, Hummel, Rene, Lin, Chung-Hsien, Su, Wang Shen, Tang, Tsung Lin, Lin, Chia Min
• Primary Examiner(s): ARMAND, MARC ANTHONY
• Application Number:
  US15/085,592
• Publication Number:
  US 20160290883A1
• Time in Patent Office: 762 Days
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2203/0315 Cavities
• CPC Class Codes: B81B 3/0089 Chemical or biological characteristics, e.g. layer which makes a surface chemically active
• CPC Class Codes: B81C 1/00285 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: G01L 9/0045 Diaphragm associated with a buried cavity
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: H01L 2224/11 Manufacturing methods
• CPC Class Codes: H01L 29/84 controllable by variation of applied mechanical force, e.g. of pressure

Abstract

A pressure sensor comprises a deformable membrane deflecting in response to pressure applied, a first stationary electrode, and a second electrode coupled to the deformable membrane, for determining a change in a capacitance between the first and the second electrode in response to the pressure applied. At least one of the first and the second electrode comprises a getter material for collecting gas molecules.

Claims

1. A pressure sensor, comprising

a deformable membrane deflecting in response to pressure applied,

a first stationary electrode and a second electrode coupled to the deformable membrane, for determining a change in a capacitance between the first and the second electrode in response to the pressure applied,

wherein the first stationary electrode comprises a getter material for collecting gas molecules wherein the first stationary electrode comprising the getter material comprises a first layer and a second layer, wherein the first layer comprises conducting material that is different from the getter material, and wherein the second layer is deposited on the first layer, and wherein the second layer faces a volume to collect the gas molecules from.

2. The pressure sensor of claim 1, wherein the getter material is a non-evaporable metal or a non-evaporable alloy.

3. The pressure sensor of claim 1, wherein the getter material is selected from a group consisting of titanium, platinum and zirconium.

4. The pressure sensor of claim 1, wherein the second layer has the shape of a cap encapsulating the first layer such that the first layer is disconnected from the volume to collect the gas molecules from.

5. The pressure sensor of claim 1, wherein the first stationary electrode comprising the getter material has a plane extension and comprises slots in the getter material orthogonal to the plane extension.

6. The pressure sensor of claim 1, wherein the first stationary electrode comprising the getter material has a plane extension and comprises slots reaching through the first layer.

7. The pressure sensor of claim 1, wherein the first stationary electrode comprising the getter material comprises individual elements comprising the getter material.

8. The pressure sensor of claim 1, wherein the first stationary electrode comprising the getter material comprises individual elements comprising the getter material, wherein each individual element comprises the first layer of conducting material different from the getter material, and wherein the second layer comprises the getter material, and wherein the second layer is deposited on the first layer.

9. The pressure sensor of claim 1, wherein the first stationary electrode comprising the getter material comprises a center portion and a ring portion around the center portion, wherein the center portion comprises a first layer and a second layer, wherein the first layer comprises conducting material that is different from the getter material, and wherein the second layer comprising the getter material is deposited on the first layer, and wherein the ring portion exclusively comprises the getter material.

10. The pressure sensor of claim 1, wherein the first stationary electrode comprising the getter material comprises a center portion and a ring portion around the center portion, wherein the center portion comprises a conducting material that is different from the getter material, and wherein the ring portion comprises the getter material.

11. The pressure sensor of claim 1, comprising a cavity, wherein the deformable membrane separates the cavity and a port open to an outside of the pressure sensor, and wherein the first stationary electrode is arranged inside the cavity.

12. The pressure sensor of claim 1, wherein only the first stationary electrode comprises the getter material, and wherein the deformable membrane is electrically conducting and wherein the deformable membrane is the second electrode.

13. The pressure sensor of claim 7, wherein the first stationary electrode comprising the getter material has a plane extension, wherein the individual elements are arranged next to each other in the plane of the first stationary electrode, and wherein each individual element is electrically connected to at least one of the neighboring individual elements.

14. The pressure sensor of claim 11, wherein the first stationary electrode is arranged at a bottom of the cavity facing the deformable membrane, and wherein the cavity is evacuated.

15. A pressure sensor, comprising

a deformable membrane deflecting in response to pressure applied,

a first stationary electrode and a second electrode coupled to the deformable membrane, for determining a change in a capacitance between the first and the second electrode in response to the pressure applied,

wherein at least one of the first and the second electrode comprises a getter material for collecting gas molecules,

wherein the at least one electrode that comprises the getter material comprises a first layer and a second layer, wherein the second layer comprises the getter material and wherein the second layer is deposited on the first layer, wherein the first layer comprises conducting material that is different from the getter material,

wherein the second layer faces a volume to collect the gas molecules from,

wherein the second layer has a plane extension and comprises slots orthogonal to the plane extension which slots reach into the first layer.

16. A pressure sensor, comprising

a deformable membrane deflecting in response to pressure applied,

a first stationary electrode and a second electrode coupled to the deformable membrane, for determining a change in a capacitance between the first and the second electrode in response to the pressure applied,

wherein at least one of the first and the second electrode comprises a getter material for collecting gas molecules,

wherein the at least one electrode that comprises the getter material comprises a center portion and a ring portion around the center portion,

wherein the center portion comprises a first layer and a second layer, wherein the first layer comprises of conducting material that is different from the getter material, and wherein the second layer comprise the getter material, and wherein the second layer is deposited on the first layer, and

wherein the ring portion exclusively comprises the getter material.