Diaphragm-based sensor with a corrugated sidewall

Patent metadata

Field	Value
Publication number	US-11504012-B2
Application number	US-202016749247-A
Country	US
Kind code	B2
Filing date	Jan 22, 2020
Priority date	Jan 25, 2019
Publication date	Nov 22, 2022
Grant date	Nov 22, 2022

Abstract

A diaphragm-based sensor includes a deflectable diaphragm, a base layer opposite the diaphragm, and a corrugated wall extending between the diaphragm and the base layer. The diaphragm is suspended over a cavity enclosed by the diaphragm, the base layer and the corrugated wall. The diaphragm includes a first electrode and the base layer includes a second electrode such that a capacitance between the first and second electrodes changes when the diaphragm is deflected relative to the cavity.

First claim

The invention claimed is:

1. A sensor comprising:
a deflectable diaphragm;
a base layer opposite the diaphragm; and
a corrugated wall extending between the diaphragm and the base layer;
wherein the diaphragm is suspended over a cavity defined by the diaphragm, the base layer and the corrugated wall.

2. The sensor of claim 1 , wherein the diaphragm comprises a first electrode and the base layer comprises a second electrode such that a capacitance between the first and second electrodes changes when the diaphragm is deflected relative to the cavity.

3. The sensor of claim 1 , wherein the corrugated wall comprises a plurality of ridges alternating with a plurality of grooves.

4. The sensor of claim 1 , wherein a ratio of a height of the corrugated wall to a diameter of the diaphragm ranges from about 0.0005 to about 1.

5. The sensor of claim 1 , wherein the diaphragm has a diameter about 800 μm.

6. The sensor of claim 1 , wherein the corrugated wall has a height about 7 μm.

7. The sensor of claim 2 , wherein the first electrode is encapsulated between at least two parylene layers.

8. The sensor of claim 2 , wherein the second electrode is encapsulated between at least two parylene layers.

9. The sensor of claim 3 , wherein each of the plurality of ridges has a rectangle-shaped radial cross-section.

10. The sensor of claim 9 , wherein the rectangle-shaped radial cross-section has a width about 80 μm and a length about 100 μm.

11. The sensor of claim 10 , wherein two adjacent ridges form a radial angle about 15 degrees.

12. The sensor of claim 1 , wherein the cavity is filled with a fluid, wherein the fluid has a dielectric constant greater than 1.

13. The sensor of claim 12 , wherein the fluid comprises propylene carbonate.

14. A method of fabricating a sensor comprising:
forming a base layer on a substrate;
forming a corrugated wall on the base layer so as to form a cavity; and
forming a diaphragm suspended over the cavity and supported by the corrugated wall.

15. The method of claim 14 , wherein the diaphragm comprises a first electrode and the base layer comprises a second electrode such that a capacitance between the first and second electrodes changes when the diaphragm is deflected relative to the cavity.

16. The method of claim 14 , wherein the cavity is formed by removing a sacrificial photoresist layer deposited between the diaphragm and the base layer.

17. The method of claim 16 , wherein the sacrificial photoresist layer is patterned to have a body portion having a corrugated side surface.

18. The method of 16 further comprising filling the cavity with a fluid, wherein the fluid has a dielectric constant greater than 1.

19. The method of claim 18 , wherein filling the cavity with the fluid comprises submerging the base layer, the corrugated wall, and the diaphragm into a pool of the fluid for a predefined duration.

20. The method of claim 14 further comprises sealing the cavity.

Assignees

• Univ Pittsburgh Commonwealth Sys Higher Education
• Univ Pittsburgh

Inventors

• Cho Sung Kwon

Classifications

• G01L9/0048

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• A61B2562/0204

  Acoustic sensors · CPC title

• A61B2562/029

  Humidity sensors · CPC title

• B81C1/00158

  Diaphragms, membranes (manufacture process for semi-permeable inorganic membranes B01D67/0039) · CPC title

• B81B3/007 Primary

  For controlling stiffness, e.g. ribs · CPC title