Methods of environmental protection for silicon MEMS structures in cavity packages

Patent metadata

Field	Value
Publication number	US-12063474-B2
Application number	US-202217660239-A
Country	US
Kind code	B2
Filing date	Apr 22, 2022
Priority date	May 11, 2021
Publication date	Aug 13, 2024
Grant date	Aug 13, 2024

Abstract

A sound transducer device includes a multilayer component board having a first side and an opposite second side, and a sound port extending between the first and second sides of the multilayer component board. The sound transducer also includes a MEMS sound transducer die including a suspended membrane structure, wherein the MEMS sound transducer die is arranged at the first side of the multilayer component board such that the suspended membrane structure is in fluid communication with the sound port. The sound transducer also includes a mesh structure for providing an environmental barrier, the mesh structure covering the sound port from either one of the first and second sides of the multilayer component board.

First claim

What is claimed is:

1. A sound transducer device comprising:
a multilayer component board having a first side and a second side opposite the first side;
a sound port extending between the first side and the second side of the multilayer component board;
a MEMS (Micro Electro Mechanical System) sound transducer die comprising a suspended membrane structure, wherein the MEMS sound transducer die is arranged at the first side of the multilayer component board with its suspended membrane structure being in fluid communication with the sound port;
a mesh structure for providing an environmental barrier, the mesh structure covering the sound port from either one of the first side or the second side of the multilayer component board;
a first recess provided at the second side of the multilayer component board in an area in which the sound port is provided, such that the sound port is positioned between the first recess and the MEMS sound transducer die, wherein the first recess comprises a first diameter, the first diameter being larger than a diameter of the sound port; and
a second recess provided at the second side of the multilayer component board in an area in which the sound port and the first recess are provided, such that the first recess is positioned between the sound port and the second recess, wherein the second recess has a second diameter larger than the first diameter.

2. The sound transducer device according to claim 1 ,
wherein the mesh structure is a multi-mesh structure comprising at least two single meshes,
wherein a first single mesh and a second single mesh comprise or are made from the same material, or
wherein the first single mesh and the second single mesh comprise or are made from different materials.

3. The sound transducer device according to claim 1 ,
wherein the mesh structure comprises at least one single mesh being made of a chemically etched or laser cut metal.

4. The sound transducer device according to claim 1 ,
wherein the mesh structure comprises at least one single mesh comprising at least one component of a group of glass, glass-reinforced epoxy laminate material and FR4.

5. The sound transducer device according to claim 1 ,
wherein the mesh structure comprises at least one single mesh comprising or being made of a silicon platelet comprising a plurality of vertically etched through holes acting as the environmental barrier.

6. The sound transducer device according to claim 5 ,
wherein the through holes are RIE-etched (RIE: Reactive Ion Etching) through holes having a diameter configured to prevent water from passing through the silicon platelet.

7. The sound transducer device according to claim 1 ,
wherein the mesh structure is positioned at the same side of the multilayer component board as the MEMS sound transducer die, and
wherein the mesh structure is arranged between the multilayer component board and the MEMS sound transducer die.

8. The sound transducer device according to claim 1 ,
wherein the MEMS sound transducer die comprises a cavity having an inner diameter, and
wherein the sound port comprises a diameter which is larger than the inner diameter of the MEMS sound transducer die.

9. The sound transducer device according to claim 1 ,
wherein the mesh structure is positioned at a side of the multilayer component board opposite the MEMS sound transducer die with the sound port extending between the MEMS sound transducer die and the mesh structure.

10. The sound transducer device according to claim 1 ,
wherein the mesh structure is attached to the second side of the multilayer component board along a periphery of the sound port thereby covering the sound port and leaving further lateral portions of the second side of the multilayer component board uncovered.

11. The sound transducer device according to claim 1 ,
comprising a further membrane structure having a water repellant characteristic,
the further membrane structure being arranged at either one of the first side or the second side of the multilayer component board and covering the sound port.

12. The sound transducer device according to claim 1 ,
wherein the mesh structure comprises a support structure, the support structure having an indented portion in which a perforated portion of the mesh structure is provided,
wherein the indented portion extends into the first recess such that the perforated portion of the mesh structure is arranged inside the first recess.

13. The sound transducer device according to claim 1 ,
comprising a further membrane structure having a water repellant characteristic, wherein said further membrane structure is arranged inside the first recess and positioned between the mesh structure and the MEMS sound transducer die.

14. The sound transducer device according to claim 1 ,
comprising a further membrane structure having a water repellant characteristic, wherein said further membrane structure is mounted in the first recess and the mesh structure is mounted in the second recess.

15. The sound transducer device according to claim 1 ,
comprising a further membrane structure having a water repellant characteristic, wherein the mesh structure is mounted in the first recess and the further membrane structure is mounted in the second recess.

16. The sound transducer device according to claim 11 ,
wherein the further membrane structure is a multi-membrane structure comprising at least two single membranes,
wherein a first single membrane and a second single membrane comprise or are made from the same material, or
wherein the first single membrane and the second single membrane comprise or are made from different materials.

17. The sound transducer device according to claim 11 ,
wherein the further membrane structure comprises at least one single membrane comprising or being made of at least one component of a group comprising Polytetrafluoroethylene (PTFE), organic material, polysilicon and polyamide.

18. A sound transducer comprising:
a multilayer component board having a first side and a second side opposite the first side;
a sound port extending between the first side and the second side of the multilayer component board;
a micro electro mechanical system (MEMS) die comprising a suspended membrane structure, wherein the MEMS die is arranged at the first side of the multilayer component board, the suspended membrane structure being in fluid communication with the sound port;
a mesh structure providing an environmental barrier and covering the sound port;
a first recess provided at the second side of the multilayer component board at the sound port, the sound port being positioned between the first recess and the MEMS die, wherein the first recess comprises a first diameter being larger than the sound port; and
a second recess at the second side of the multilayer component board at the sound port, the first recess located between the sound port and the second recess, wherein the second recess has a second diameter larger than the first diameter.

19. A method of forming a sound transducer device, the method comprising:
providing a multilayer component board having a first side and a second side opposite the first side;
providing a sound port extending between the first side and the second side of the multilayer component board;
providing a micro electro mechanical system (MEMS) die comprising a suspended membrane structure, wherein the MEMS die is arranged at the first side of the multilayer component board, the suspended membrane structure being in fluid co

Assignees

• Infineon Technologies Ag

Inventors

• Westmarland Paul
• Goller Bernd
• Palmer Scott
• Pavier Mark

Classifications

• H04R2307/025

  Diaphragms comprising polymeric materials · CPC title

• H04R2201/003

  Mems transducers or their use · CPC title

• H04R7/18

  at the periphery · CPC title

• H04R7/06

  comprising a plurality of sections or layers · CPC title

• H10N30/802

  Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits · CPC title