Microelectromechanical system microphone fabrication including signal processing circuitry on common substrate

• US 7,358,151 B2
• Filed: 12/21/2004
• Issued: 04/15/2008
• Est. Priority Date: 12/21/2004
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Kuhn, Martin, Araki, Shinichi
• Primary Examiner(s): Smith; Zandra V.
• Assistant Examiner(s): Perkins; Pamela E
• Application Number:
  US11/022,457
• Publication Number:
  US 20060134904A1
• Time in Patent Office: 1,211 Days
• Field of Search: 438/48, 438/453, 438/622, 438/662
• US Class Current: 438/453
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81C 1/00246 Monolithic integration, i.e. micromechanical structure and electronic processing unit are integrated on the same substrate
• CPC Class Codes: B81C 2203/0735 Post-CMOS, i.e. forming the micromechanical structure after the CMOS circuit

Abstract

A MEMS microphone is formed on a single substrate that also includes microelectronic circuitry. High-temperature tolerance metals are used to form contacts in a metallization step before performing deep reactive ion etching and back patterning steps to form a MEMS microphone. High-temperature tolerant metals such as titanium, tungsten, chromium, etc. can be used for the contacts. Another approach uses laser annealing in place of deep reactive ion etching so that high-temperature tolerant metals do not need to be used in earlier metallization steps. Different orderings for device, circuit, and metallization series of steps are presented.

Claims

1. A method comprising:

forming at least a portion of a microelectromechanical device on a substrate;

fabricating at least a portion of a microelectronic circuit on the substrate, wherein fabricating includes a circuit metallization process; and

subsequent to the fabricating, completing formation of the microelectromechanical device by using a device metallization process to fabricate an electrically conductive trace that carries electric signals between the microelectromechanical device and the microelectronic circuit, wherein completing formation of the microelectromechanical device includes using a laser.

2. The method of claim 1, wherein the microelectromechanical device includes a microphone.

3. The method of claim 1, wherein the microelectromechanical device includes a condenser microphone.

4. The method of claim 1, wherein the circuit metallization process includes using a high-temperature metallization material.

5. The method of claim 4, wherein the high-temperature metallization material includes tungsten.

6. The method of claim 4, wherein the high-temperature metallization material includes tungsten silicide.

7. The method of claim 4, wherein the high-temperature metallization material includes chromium.

8. The method of claim 4, wherein the high-temperature metallization material includes titanium.

9. The method of claim 1, wherein the microelectronic circuit includes a noise-reduction circuit.

10. The method of claim 1, wherein the microelectronic circuit includes a signal conditioning circuit.

11. The method of claim 1, wherein the circuit metallization process includes using a low-temperature metallization material.

12. A method comprising:

fabricating at least a portion of a microelectronic circuit on a substrate including a circuit metallization process, wherein the circuit metallization process uses a high temperature metallization material, wherein the high-temperature metallization material includes tungsten, tungsten silicide, chromium, and/or titanium; and

subsequent to the fabricating step, forming a microelectromechanical device including a device metallization process, wherein the microelectronic circuit includes a noise-reduction circuit.

13. The method of claim 12, wherein the microelectronic circuit includes a signal conditioning circuit.

14. The method of claim 12, wherein the microelectromechanical device includes a microphone.

15. The method of claim 12, wherein the microelectromechanical device includes a condenser microphone.