Membrane arrangement for a microelectromechanical measuring transducer and method for producing a membrane arrangement

• US 9,516,423 B2
• Filed: 03/05/2013
• Issued: 12/06/2016
• Est. Priority Date: 04/12/2012
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Daley, Mike, Scheben, Rolf, Schelling, Christoph
• Primary Examiner(s): Ensey, Brian
• Application Number:
  US14/391,139
• Publication Number:
  US 20150078590A1
• Time in Patent Office: 1,372 Days
• Field of Search: 381/174, 381/175, 381/191
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0257 Microphones or microspeakers
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• 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 3/007 For controlling stiffness, e.g. ribs
• CPC Class Codes: B81B 3/0086 Electrical characteristics, e.g. reducing driving voltage, improving resistance to peak voltage
• CPC Class Codes: B81C 1/00158 Diaphragms, membranes manufacture process for semi-permeable inorganic membranes B01D67/0039
• CPC Class Codes: H04R 17/005 using a piezoelectric polymer

Abstract

The disclosure relates to a micro-electromechanical membrane arrangement with a substrate, which has a multiplicity of recesses on a surface, a first electrically conductive electrode layer, which is arranged on the surface of the substrate and has a multiplicity of first depressions coinciding with the recesses, and an electrically conductive membrane layer, which can be deflected in a direction perpendicular to the active surface of the substrate, is arranged over the first electrode layer and is kept at a distance therefrom by a first distance value.

Claims

1. A microelectromechanical membrane arrangement, comprising:

a substrate having an upper surface in which a plurality of cutouts are defined;

a first electrically conductive electrode layer arranged on the surface of the substrate and along walls of the cutouts, thereby defining a plurality of first depressions corresponding to the plurality of cutouts; and

an electrically conductive membrane layer configured to be deflected in a direction perpendicular to the surface of the substrate, arranged over the first electrode layer, and spaced apart from the first electrode layer by a first distance.

2. The membrane arrangement as claimed in claim 1, wherein the membrane layer defines a plurality of downwardly extending second depressions formed over and aligned with corresponding first depressions of the plurality of first depressions.

3. The membrane arrangement as claimed in claim 2, wherein the second depressions are configured to extend within the corresponding first depressions of the plurality of first depressions, each of the second depressions and each of the corresponding first depressions being spaced apart from one another when the membrane layer is deflected perpendicular to the surface of the substrate.

4. The membrane arrangement as claimed in claim 2, wherein the second depressions have outer walls having a vertical extent which is greater than the first distance.

5. The membrane arrangement as claimed in claim 2, wherein the second depressions have outer walls with a vertical extent which is equal to the first distance.

6. The membrane arrangement as claimed in claim 2, wherein outer walls of the first depressions are spaced apart from outer walls of the second depressions by a second distance in a direction parallel to the surface of the substrate.

7. The membrane arrangement as claimed in claim 1, further comprising:

a second electrically conductive electrode layer arranged over the membrane layer and defining a plurality of third depressions formed over the plurality of first depressions.

8. The membrane arrangement as claimed in claim 7, wherein outer walls of the second depressions are spaced apart from outer walls of the third depressions by a second distance in a direction parallel to the surface of the substrate.

9. The membrane arrangement as claimed in claim 1, wherein the first electrode layer and the substrate define a plurality of first pressure compensation holes formed in a floor portion of the first depressions.

10. The membrane arrangement as claimed in claim 1, wherein the first electrode layer is formed by the substrate.

11. The membrane arrangement as claimed in claim 2, wherein the membrane layer defines a plurality of second pressure compensation holes formed between the second depressions.

12. The membrane arrangement as claimed in claim 7, wherein the second electrode layer defines a plurality of third pressure compensation holes formed at least one of in the third depressions and between the third depressions.

13. A microelectromechanical component having a microelectromechanical membrane arrangement, comprising:

a substrate having a surface in which a plurality of cutouts are defined;

a first electrically conductive electrode layer arranged on the surface of the substrate and along walls of the cutouts, thereby defining a plurality of first depressions corresponding to the plurality of cutouts; and

an electrically conductive membrane layer configured to be deflected in a direction perpendicular to the surface of the substrate, arranged over the first electrode layer, and spaced apart from the first electrode layer by a first distance.

14. The microelectromechanical component as claimed in claim 13, wherein the microelectromechanical component is one of a pressure sensor, a microphone and a loudspeaker.

15. A method for producing a membrane arrangement, comprising:

introducing a plurality of cutouts into a surface of a semiconductor substrate;

forming a first electrically conductive electrode layer on the surface of the substrate and along walls of the cutouts, the electrode layer defining a plurality of first depressions coinciding with the plurality of cutouts;

forming an oxide layer on the first electrode layer;

depositing an electrically conductive membrane layer on the oxide layer;

forming first through-holes in the substrate and the first electrode layer; and

etching the oxide layer through the first through-holes in order to free the membrane layer such that the membrane layer is configured to deflect with respect to the first electrode layer and spaced apart from the first electrode layer by a first distance.

16. A microelectromechanical membrane arrangement, comprising:

a substrate having a surface in which a plurality of cutouts are defined;

a first electrically conductive electrode layer arranged on the surface of the substrate and defining a plurality of first depressions corresponding to the plurality of cutouts; and

an electrically conductive membrane layer configured to be deflected in a direction perpendicular to the surface of the substrate, arranged over the first electrode layer, and spaced apart from the first electrode layer by a first distance,

wherein the membrane layer defines a plurality of second depressions formed over the plurality of first depressions, and

wherein the second depressions are configured to engage in corresponding first depressions of the plurality of first depressions, each of the second depressions and each of the corresponding first depressions being spaced apart from one another when the membrane layer is deflected perpendicular to the surface of the substrate.

17. The membrane arrangement as claimed in claim 16, wherein the second depressions have outer walls having a vertical extent which is greater than the first distance.

18. The membrane arrangement as claimed in claim 16, wherein the second depressions have outer walls with a vertical extent which is equal to the first distance.

19. A microelectromechanical membrane arrangement, comprising:

a substrate having a surface in which a plurality of cutouts are defined;

a first electrically conductive electrode layer arranged on the surface of the substrate and defining a plurality of first depressions corresponding to the plurality of cutouts;

an electrically conductive membrane layer configured to be deflected in a direction perpendicular to the surface of the substrate, arranged over the first electrode layer, and spaced apart from the first electrode layer by a first distance; and

a second electrically conductive electrode layer arranged over the membrane layer and defining a plurality of third depressions formed over the plurality of first depressions.

20. A microelectromechanical membrane arrangement, comprising:

a substrate having a surface in which a plurality of cutouts are defined;

a first electrically conductive electrode layer arranged on the surface of the substrate and defining a plurality of first depressions corresponding to the plurality of cutouts;

an electrically conductive membrane layer configured to be deflected in a direction perpendicular to the surface of the substrate, arranged over the first electrode layer, and spaced apart from the first electrode layer by a first distance,

wherein the membrane layer defines a plurality of second depressions formed over the plurality of first depressions, and

wherein the membrane layer defines a plurality of second pressure compensation holes formed between the second depressions.