Electrical Module Comprising a Mems Microphone

• US 20080247585A1
• Filed: 02/08/2006
• Published: 10/09/2008
• Est. Priority Date: 02/24/2005
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: Epcos AG (TDK Corporation)
• Inventors: Pahl, Wolfgang, Leidl, Anton, Wolff, Ulrich
• Granted Patent: US 8,184,845 B2
• Time in Patent Office: Days
• US Class Current: 381/360
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 2203/0127 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 Class Codes: B81B 2207/012 the micromechanical device and the control or processing electronics being separate parts in the same package
• 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: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/1461 MEMS
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H04R 17/02 Microphones

Abstract

An electrical module includes a base plate having an acoustic channel that opens into a first cavity at a first end and that is closed off by a microphone chip at a second end. The microphone chip borders a second cavity that opens to an exterior of the electrical module. The second cavity is separated from the acoustic channel by the microphone chip.

Claims

1. An electrical module comprising:

a base plate having an acoustic channel that opens into a first cavity at a first end and that is closed-off by a microphone chip at a second end.

2. The electrical module of claim 1, wherein the microphone chip borders a second cavity that opens to an exterior of the electrical module;

and

wherein the second cavity is separated from the acoustic channel by the microphone chip.

3. The electrical module of claim 1, further comprising:

a cover that seals to the base plate, wherein the first cavity is between the base plate and the cover.

4. The electrical module of claim 2, further comprising:

a cover that seals to the base plate;

wherein the first and second cavities are between the base plate and the cover.

5. The electrical module of claim 4, wherein the cover comprises a separation ridge that separates the first and second cavities.

6. The electrical module of claim 1, wherein the acoustic channel comprises a tunnel extending in a longitudinal direction.

7. The electrical module of claim 2, wherein the second cavity is connected to a sound inlet opening.

8. The electrical module of claim 1, wherein the microphone chip is above a first opening in the base plate;

and

wherein the base plate has a second opening through which the acoustic channel is connected to the first cavity.

9. The electrical module of claim 1, wherein the base plate comprises a first layer having a recess and a second layer above the first layer in an area of the recess that forms at least two openings, the acoustic channel being in the recess.

10. The electrical module of claim 9, further comprising:

a cover that seals to the second layer, wherein the cover comprises a separation ridge that seals to the second layer and that separates the first cavity from a second cavity.

11. The electrical module of claim 2, further comprising:

at least one chip element in the first cavity, the at least one element comprising a resistor, a capacitor, an inductor, a filter, an impedance transformer, or an amplifier.

12. The electrical module of claim 1, wherein the microphone chip has contact surfaces that are electrically connected, via bonding wires, to electrical contacts on an upper side of the base plate.

13. The electrical module of claim 11, wherein the microphone chip has contact surfaces that are electrically connected, via bonding wires, to electrical contacts on an upper side of a chip element.

14. The electrical module of claim 1, wherein the microphone chip is mounted in a flip-chip configuration, and wherein the microphone chip is electrically connected, via bumps, to electrical contacts on an upper side of the base plate.

15. The electrical module of claim 2, wherein the acoustic channel runs, at least in part, below the first and second cavities.

16. The electrical module of claim 1, further comprising:

a sealing frame between the microphone chip and the base plate.

17. The electrical module of claim 16, wherein the sealing frame comprises an adhesive or a molding compound.

18. The electrical module of claim 16, wherein the sealing frame comprises a solder frame.

19. An electrical module comprising:

a base plate having a recess that defines an acoustic channel, the base plate comprising a first layer and a second layer, the second layer being above the first layer and above at least part of the recess to form a first opening and a second opening;

a microphone chip connected to the second layer and over the second opening;

a cover having a separation ridge, the cover and the separation ridge being sealed to the second layer, the cover being over the first opening and over the microphone chip, the separation ridge forming a first cavity over the first opening and a second cavity over the microphone chip, the first cavity being closed to an exterior of the electrical module, and the second cavity being having a third opening to the exterior; and

at least one chip element electrically connected to the second layer and in the first cavity.

20. The electrical module of claim 19, wherein the microphone chip has a contact surface that is electrically connectable to a first electrode of a microphone and to an electrical contact on the second layer.