Pre-collapsed capacitive micro-machined transducer cell with annular-shaped collapsed region

Patent metadata

Field	Value
Publication number	US-9762148-B2
Application number	US-201214351888-A
Country	US
Kind code	B2
Filing date	Nov 5, 2012
Priority date	Nov 17, 2011
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

The present invention relates to a pre-collapsed capacitive micro-machined transducer cell ( 10 ) comprising a substrate ( 12 ) comprising a first electrode ( 16 ), a membrane ( 14 ) comprising a second electrode ( 18 ), wherein the cell has an outer region ( 22 ) where the membrane ( 14 ) is mounted to the substrate ( 12 ) and an inner region ( 20 ) inside or surrounded by the outer region ( 22 ), wherein the membrane ( 14 ) is collapsed to the substrate ( 12 ) in a first collapsed annular-shaped region ( 24 ) located within the inner region ( 20 ).

First claim

The invention claimed is:

1. A pre-collapsed capacitive micro-machined transducer cell comprising:
a substrate comprising a first electrode,
a membrane comprising a second electrode,
an outer region including a support where the membrane is mounted to the substrate,
an inner region surrounded by the outer region,
wherein the membrane is collapsed to the substrate in an annular-shaped first collapsed region located within the inner region to form an annular-shaped cavity between the membrane and the substrate which surrounds the annular-shaped first collapsed region, wherein a height of the annular-shaped cavity continuously decreases from the support to the annular-shaped first collapsed region; and
wherein the second electrode is located above the annular-shaped cavity to provide a transduction region surrounding the annular-shaped first collapsed region.

2. The cell of claim 1 , wherein the second electrode is located at least in close proximity to the annular-shaped first collapsed region.

3. The cell of claim 1 , wherein the second electrode and/or the first electrode have/has an annular shape.

4. The cell of claim 1 , wherein the annular-shaped first collapsed region is located centered around the center of the cell or membrane.

5. The cell of claim 1 , wherein the membrane is further collapsed to the substrate in a second collapsed region located within the inner region.

6. The cell of claim 5 , wherein the second collapsed region is located in a center region or in the center of the cell or membrane.

7. The cell of claim 1 , wherein the membrane has a built-in stress in the inner region, wherein the built-in stress is controlled through stoichiometry of the membrane, use of a multilayer membrane, or combinations thereof.

8. The cell of claim 1 , the membrane further comprising a third electrode located in the first collapsed region.

9. The cell of claim 8 , wherein the second electrode and/or the third electrode have/has at least one opening, and wherein a connector to the fourth electrode and/or the second electrode are/is located in the opening.

10. The cell of claim 1 , wherein the membrane is permanently collapsed.

11. The cell of claim 1 , wherein the membrane is collapsed only during operation of the cell.

12. The cell of claim 1 , further comprising a second collapsed region located within the inner region and a third electrode located within the second collapsed region.

13. The cell of claim 1 , wherein the transduction region surrounding the annular-shaped first collapsed region is a first transduction region, and wherein the cell further comprises another electrode located over a second cavity surrounded by the annular-shaped first collapsed region to provide a second transduction region inside the inner region.

14. A method of manufacturing a pre-collapsed capacitive micro-machined transducer cell, the method comprising:
providing a substrate comprising a first electrode,
providing a membrane comprising a second electrode, wherein the cell has an outer region including a support where the membrane is mounted to the substrate, and an inner region surrounded by the outer region, and
collapsing the membrane to the substrate in a annular-shaped first collapsed region located within the inner region to form an annular-shaped cavity between the membrane and the substrate, wherein the annular-shaped cavity surrounds the annular-shaped first collapsed region, and wherein a height of the annular-shaped cavity continuously decreases from the support to the annular-shaped first collapsed region,
wherein the providing a membrane comprising a second electrode includes locating the second electrode above the annular-shaped cavity to
provide transduction region surrounding the annular-shaped first collapsed region.

15. The method of claim 14 , the membrane further comprising a third electrode located in the annular-shaped first collapsed region,
wherein collapsing the membrane to the substrate comprises applying a voltage between the first electrode and the third electrode.

16. The method of claim 14 , wherein the transduction region surrounding annular-shaped the first collapsed region is a first transduction region, the method further comprising providing another electrode over a second cavity surrounded by the annular-shaped first collapsed region to provide a second transduction region inside the inner region.

Assignees

• Koninklijke Philips Nv

Inventors

• Robinson Andrew Lee
• Fraser John Douglas

Classifications

• H02N1/006 Primary

  of the gap-closing type (H02N1/004 takes precedence) · CPC title

• Y10T29/49005

  Acoustic transducer · CPC title

• B06B1/02 Primary

  making use of electrical energy (B06B1/18, B06B1/20 take precedence) · CPC title

• B06B1/0292 Primary

  Electrostatic transducers, e.g. electret-type · CPC title