Silicon Microphone

• US 20080175417A1
• Filed: 05/15/2006
• Published: 07/24/2008
• Est. Priority Date: 05/16/2005
• Status: Active Grant

• Current Assignee: Sensfab Pte., Ltd. (Mems Technology Berhad)
• Original Assignee: Sensfab Pte., Ltd. (Mems Technology Berhad)
• Inventors: Patmon, Bryan Keith, Sooriakumar, Kathirgamasundaram, Kok, Kitt-Wai, Ong, Kok Meng
• Granted Patent: US 8,098,870 B2
• Time in Patent Office: Days
• US Class Current: 381/174
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• CPC Class Codes: H04R 19/005 using semiconductor materials

Abstract

A silicon microphone comprising a backplate of electrically conductive or semi-conductive material comprising a rigid aperture area and a surrounding area, a diaphragm of electrically conductive or semi-conductive material comprising a flexible member that extends over the aperture area and a surrounding area that is at least partially connected to, and insulated from, the surrounding area of the backplate, the aperture area of the backplate and flexible member of the diaphragm forming two parallel plates of a capacitor spaced apart by a cavity, a bond pad formed on the surrounding area of the diaphragm, a bond pad formed on the surrounding area of the backplate, a channel formed in the diaphragm surrounding the bond pad formed on the surrounding area of the backplate, at least one air channel formed in the surrounding area of the diaphragm and open into the cavity between the flexible member and the aperture area of the backplate, and at least one vent through the surrounding area of the diaphragm connected to each air channel.

Claims

1. A silicon microphone comprising

a backplate of electrically conductive or semi-conductive material comprising a rigid aperture area and a surrounding area,

a diaphragm of electrically conductive or semi-conductive material comprising a flexible member that extends over the aperture area and a surrounding area that is at least partially connected to, and insulated from, the surrounding area of the backplate,

the aperture area of the backplate and flexible member of the diaphragm forming two parallel plates of a capacitor spaced apart by a cavity,

a bond pad formed on the surrounding area of the diaphragm,

a bond pad formed on the surrounding area of the backplate,

a channel formed in the diaphragm surrounding the bond pad formed on the surrounding area of the backplate, at least one air channel formed in the surrounding area of the diaphragm and open into the cavity between the flexible member and the aperture area of the backplate, and

at least one vent through the surrounding area of the diaphragm connected to each air channel.

2. A silicon microphone as claimed in claim 1 wherein the channels surrounding the bond pads are between 40 and 50 microns wide.

3. A silicon microphone as claimed in claim 1 wherein two air channels are provided.

4. A silicon microphone as claimed in claim 1 wherein each air channel is about 20 microns wide.

5. A silicon microphone as claimed in claim 1 wherein each air channel has a circuitous route.

6. A silicon microphone as claimed in claim 1 wherein the silicon microphone is provided with one air vent per air channel.