Waterproof microphone and associated packing techniques

• US 10,562,761 B2
• Filed: 11/17/2016
• Issued: 02/18/2020
• Est. Priority Date: 11/18/2015
• Status: Active Grant

• Current Assignee: Darcet Company Limited
• Original Assignee: Anu Austin, Ian Rose Bihag, Kathirgamasundaram Sooriakumar
• Inventors: Sooriakumar, Kathirgamasundaram, Austin, Anu, Bihag, Ian Rose
• Primary Examiner(s): Luke, Daniel
• Application Number:
  US15/354,562
• Publication Number:
  US 20170137282A1
• Time in Patent Office: 1,188 Days
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2207/11 Structural features, others than packages, for protecting a device against environmental influences
• CPC Class Codes: B81B 2207/99 Microstructural systems or auxiliary parts thereof not provided for in B81B2207/01 - B81B2207/115
• CPC Class Codes: B81B 7/0038 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: B81B 7/0061 suitable for fluid transfer from the MEMS out of the package or vice versa, e.g. transfer of liquid, gas, sound
• CPC Class Codes: H04R 1/04 Structural association of microphone with electric circuitry therefor in deaf-aid sets H04R25/00
• CPC Class Codes: H04R 1/2876 by means of damping material, e.g. as cladding damping material for tuning desired resonances H04R1/2807, e.g. in vents H04R1/2823, H04R1/2846
• CPC Class Codes: H04R 1/44 Special adaptations for subaqueous use, e.g. for hydrophone
• CPC Class Codes: H04R 17/02 Microphones
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence
• CPC Class Codes: H04R 2201/003 Mems transducers or their use

Abstract

Aspects of the disclosure provide a waterproof packaging technique for fabricating waterproof microphones in mobile devices. A device based on the waterproof packaging technique can include a microelectromechanical system (MEMS) device, a housing enclosing the MEMS device, and a liquid-resistant air inlet passive device (LRAPD) on the housing. The LRAPD can include at least one channel connecting an exterior of the housing with a chamber formed between the housing and the MEMS device. An inside surface of the channel can be coated with a liquid-repellant coating. In some examples, the liquid-repellant coating can be a self-assembled monolayer (SAM) coating.

Claims

1. A device, comprising:

a microelectromechanical system (MEMS) device;

a housing enclosing the MEMS device, wherein a chamber is formed between the housing and the MEMS device, the chamber is a single continuous space fluidically connected to an exterior of the housing, the MEMS device is a rectangle in a sectional view, the chamber is in contact with at least three sides of the rectangle in the sectional view of the MEMS device; and

a liquid-resistant air inlet passive device (LRAPD), the LRAPD being separate from the housing and attached to the housing, the LRAPD including at least one channel connecting the exterior of the housing with the chamber.

2. The device of claim 1, wherein the entire inside surface of the channel is coated with a liquid-repellant coating.

3. The device of claim 2, wherein

the liquid-repellant coating is a self-assembled monolayer (SAM) coating.

4. The device of claim 1, wherein the LRAPD is attached to an inner side of the housing with an inlet of the channel connected to an opening in the housing.

5. The device of claim 1, wherein the LRAPD is attached to an outer side of the housing with an outlet of the channel connected to an opening in the housing.

6. The device of claim 1, wherein the LRAPD is disposed in an opening of the housing.

7. The device of claim 1, wherein

the LRAPD includes multiple channels connecting an exterior of the housing with the chamber, and

surfaces of the multiple channels are coated with a liquid-repellant coating.

8. The device of claim 1, wherein the housing includes a cover over a substrate supporting the MEMS device, and the LRAPD is attached to the cover.

9. The device of claim 1, wherein the MEMS device is a pressure sensor.

10. The device of claim 9, wherein

the MEMS device is a piezoresistive pressure sensor.

11. The device of claim 9, wherein the

MEMS device is a capacitive pressure sensor.

12. The device of claim 1, wherein the MEMS device is an acoustic pressure sensor with a sensing surface facing the chamber, and the channel of the LRAPD is formed in a direction of the sensing surface to allow an acoustic wave to reach the sensing surface.

13. The device of claim 1, wherein the MEMS device is an acoustic pressure sensor with a surface of a diaphragm opposite a sensing surface facing the chamber, and the LRAPD is configured to provide an air pressure in the chamber which is equal to atmospheric pressure.

14. The device of claim 13, wherein the acoustic pressure sensor includes a cavity between the sensing surface and the housing with an opening in the housing connecting the cavity with the exterior of the housing, and the LRAPD covers the opening.

15. The device of claim 1, wherein the LRAPD includes a zigzag channel.

16. The device of claim 1, wherein

the LRAPD includes a cavity proximate the channel to collect liquid.

17. The device of claim 1, wherein the MEMS device is an acoustic pressure sensor with a sensing surface facing the chamber, and

the channel of the LRAPD includes a longest portion running parallel from a first end to a second end with respect to the sensing surface to allow an acoustic wave to reach the sensing surface.

18. The device of claim 1, wherein the MEMS device is an acoustic pressure sensor with a sensing surface facing the chamber, and

the channel of the LRAPD includes a portion sloping from one end to the other end with respect to the sensing surface to allow an acoustic wave to reach the sensing surface.