MEMS devices and processes

Patent metadata

Field	Value
Publication number	US-10730747-B2
Application number	US-201816179162-A
Country	US
Kind code	B2
Filing date	Nov 2, 2018
Priority date	Nov 9, 2017
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

The present application relates to MEMS transducer comprising a membrane electrode and a backplate electrode. The membrane electrode comprises primary and secondary openings.

First claim

The invention claimed is:

1. A MEMS transducer comprising:
a flexible membrane;
a layer of conductive material provided on a first surface of the flexible membrane to form a membrane electrode, the layer of conductive material comprising a plurality of primary openings;
wherein an intermediate section of conductive material is defined between first and second adjacent primary openings, and wherein said intermediate section of conductive material is provided with a secondary opening;
a backplate comprising a backplate electrode, the backplate electrode having a plurality of holes;
wherein each primary opening formed in the membrane electrode at least partially underlies a corresponding hole in the backplate electrode and wherein the secondary opening at least partially underlies a corresponding intermediate section of conductive material provided between first and second adjacent holes of a backplate electrode.

2. A MEMS transducer as claimed in claim 1 , wherein a notional line drawn between the centres of the first and second adjacent primary openings intersects the intermediate section of conductive material that is between them.

3. A MEMS transducer as claimed in claim 1 , wherein the intermediate section of conductive material comprises an elongate beam having a longitudinal axis.

4. A MEMS transducer as claimed in claim 1 , wherein the secondary opening defines an elongate shape having a longitudinal axis.

5. A MEMS transducer as claimed in claim 3 , wherein the secondary opening defines an elongate shape having a longitudinal axis, and wherein the longitudinal axis of the secondary opening is substantially aligned with, or parallel to, the longitudinal axis of the intermediate section of conductive material.

6. A MEMS transducer as claimed in claim 2 , wherein the secondary opening defines an elongate shape having a longitudinal axis, and wherein the longitudinal axis of the secondary opening extends in a direction that is substantially orthogonal to the notional line.

7. A MEMS transducer as claimed in claim 1 , wherein the area of said primary opening formed in the membrane electrode substantially corresponds to the area of the corresponding hole in the backplate electrode.

8. A MEMS transducer as claimed in claim 1 , wherein one or more of the shape and size of said primary opening in the membrane electrode is substantially the same shape and size respectively as the corresponding hole in the backplate electrode.

9. A MEMS transducer as claimed in claim 1 , wherein the perimeter of the backplate hole substantially maps onto the perimeter of the corresponding primary opening in the membrane electrode when projected onto the plane of the membrane electrode in a direction normal to the membrane.

10. A MEMS transducer as claimed in claim 1 , wherein when a given hole in the backplate electrode is projected onto the plane of the membrane electrode in a direction normal to the backplate electrode, an area of the corresponding opening in the membrane electrode is within the area of the hole.

11. A MEMS transducer as claimed in claim 1 , wherein a first width of a given primary opening in the membrane electrode is smaller than a second width of the corresponding hole in the backplate electrode.

12. A MEMS transducer as claimed in claim 1 , wherein a plurality of secondary openings are provided around one said primary opening, each secondary opening being provided in an intermediate section of conductive material that is between said primary opening and an adjacent primary opening.

13. A MEMS transducer as claimed in claim 1 , wherein the membrane electrode comprises a plurality of primary openings which define a lattice structure, wherein in a first region of the membrane electrode, a plurality of secondary openings is provided relative to the perimeter of each of the primary openings.

14. A MEMS transducer as claimed in claim 13 , wherein said first region of the membrane electrode comprises a central region of the membrane electrode.

15. A MEMS transducer as claimed in claim 13 , wherein said first region of the membrane electrode overlies a cavity provided in a substrate of the MEMS transducer.

16. A MEMS transducer as claimed in claim 1 wherein the flexible membrane comprises a crystalline or polycrystalline material, such as silicon nitride, and wherein the membrane electrode comprises metal or a metal alloy, such as aluminium alloy.

17. A MEMS transducer comprising:
a membrane electrode comprising a plurality of openings;
a backplate electrode provided in a plane above the membrane and comprising a plurality of holes;
wherein each hole in the backplate electrode is at least partly aligned with a corresponding opening in the membrane electrode,
wherein the membrane electrode comprises a secondary opening which underlies an intermediate section of conductive material formed between two adjacent holes in the backplate electrode.

18. A MEMS transducer comprising:
a flexible membrane comprising a membrane electrode;
wherein the membrane electrode comprises a plurality of primary openings and a plurality of secondary openings
wherein said secondary openings are between said primary openings.

19. An integrated circuit comprising a MEMS transducer as claimed in claim 1 and further comprising readout circuitry.

Assignees

• Cirrus Logic Int Semiconductor Ltd
• Cirrus Logic Inc

Inventors

• Jenkins Colin Robert

Classifications

• 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

• B81B2203/0127

  Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function · CPC title

• H04R2201/003

  Mems transducers or their use · CPC title

• B81B2201/0257

  Microphones or microspeakers · CPC title

• H04R19/005 Primary

  using semiconductor materials · CPC title