Micromechanical sound transducer system and a corresponding manufacturing method

Abstract

A micromechanical sound transducer system and a corresponding manufacturing method, in which the micromechanical sound transducer system includes a substrate having a front side and a back side, the substrate having a through opening extending between the back side and the front side, and a coil configuration on the front side having a coil axis, which runs essentially parallel to the front side, the coil configuration covering the through opening at least partially. Also provided is a magnet device, which is situated so as to allow for an axial magnetic flux to be generated through the coil configuration. The coil configuration has a winding device which has at least first winding sections made from at least one layer of a low-dimensional conductive material, the coil configuration being configured to inductively detect and/or generate sound.

Claims

1. A micromechanical sound transducer system, comprising: a substrate having a front side and a back side, and having a through opening extending between the back side and the front side; a coil configuration having a coil axis on the front side, which essentially runs parallel to the front side, the coil configuration at least partially covering the through opening; a magnet device situated so as to allow an axial magnetic flux through the coil device to be generated; wherein the coil configuration includes a winding device having at least first winding sections made of at least one layer of a low-dimensional conductive material, wherein the first winding sections are strip-shaped and cover the through opening, and wherein the coil configuration is configured so as to be able inductively to at least one of detect sound and produce sound.

2. The micromechanical sound transducer system of claim 1, wherein the low-dimensional conductive material is one-dimensional or two-dimensional.

3. The micromechanical sound transducer system of claim 1, wherein the low-dimensional conductive material is selected from at least one of the following: graphene, silicene, divanadium pentaoxide, carbon nano tubes, carbon nano ribbons, dichalcogenide.

4. The micromechanical sound transducer system of claim 1, wherein the first winding sections above the through opening run essentially in a coplanar manner with respect to the front side.

5. The micromechanical sound transducer system of claim 1, wherein the first winding sections extend into a periphery of the through opening above the front side.

6. The micromechanical sound transducer system of claim 4, wherein the first winding sections are applied on a diaphragm region, which covers the through opening.

7. The micromechanical sound transducer system of claim 1, wherein the first winding sections are followed by second winding sections, which run essentially perpendicular to the front side, and wherein the second winding sections are followed by third winding sections, which run essentially in a coplanar manner with respect to the front side and at a distance from the first winding sections.

8. The micromechanical sound transducer system of claim 1, wherein the second winding sections and the third winding sections are manufactured from a material that differs from the low-dimensional conductive material.

9. The micromechanical sound transducer system of claim 1, wherein the third winding sections have perforations for sound to pass through.

10. The micromechanical sound transducer system of claim 1, wherein the substrate is attached with its back side on a carrier having a carrier opening, which is in fluid communication with the through opening, and wherein a cover is attached on the carrier above the front side, which defines an enclosed back volume.

11. The micromechanical sound transducer system of claim 1, wherein the magnet device is situated above the front side on the substrate in the direction of the coil axis.

12. The micromechanical sound transducer system of claim 1, wherein the magnet device is integrated in a wall of the cover in the direction of the coil axis.

13. The micromechanical sound transducer system of claim 1, wherein the through opening has on the back side a cavity and connected to it a through hole.

14. The micromechanical sound transducer system of claim 1, wherein the low-dimensional conductive material is selected from at least one of the following: graphene, silicene, divanadium pentaoxide, carbon nano tubes, carbon nano ribbons, dichalcogenide, in particular molybdenum disulfide, tungsten disulfide, titanium disulfide, and molybdenum dioxide.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1a, 1b, and 1c show schematic representations of a micromechanical sound transducer system according to a first specific embodiment of the present invention, namely, FIG. 1a in a first vertical cross section, FIG. 1b in a second vertical cross section along the line A-A, and FIG. 1c in a top view.

(2) FIG. 2 shows a schematic vertical cross-sectional representation of a micromechanical sound transducer system according to a second specific embodiment of the present invention.

(3) FIG. 3 shows a schematic vertical cross-sectional representation of a micromechanical sound transducer system according to a third specific embodiment of the present invention.

DETAILED DESCRIPTION

(4) In the figures, identical reference symbols denote identical or functionally corresponding elements.

(5) FIGS. 1a)-c) show schematic representations of a micromechanical sound transducer system according to a first specific embodiment of the present invention, namely, FIG. 1) in a first vertical cross section, FIG. 1b) in a second vertical cross section along the line A-A, and FIG. 1c) in a top view.

(6) In FIGS. 1a)-c), reference numeral 1 indicates a substrate having a front side VS and a back side RS, which is formed for example from a semiconductor material (e.g. silicon), glass or ceramics. Substrate 1 has a through opening K, FZ extending between back side RS and front side VS, which includes a cavity K on the back side and an adjacent through hole FZ. It is possible to configure such a substrate geometry by a known back side etching process using appropriate etch stop layers.

(7) On the front side VS, in the periphery of through hole FZ, there is an insulating layer I, made of an oxide for example. Above insulating layer I, a coil configuration SA is configured having a coil axis X, which runs essentially in parallel to the front side VS, the coil configuration SA covering the through hole FZ of through opening K, FZ. The coil configuration has a winding device having a plurality of windings W1, W2, W3, W4, which have first winding sections N1, N2, N3 made of at least one layer of a low-dimensional conductive material.

(8) The low-dimensional conductive material is for example graphene, silicene, divanadium pentaoxide, carbon nano tubes, carbon nano ribbons, a dichalcogenide, in particular molybdenum disulfide, tungsten disulfide, titanium disulfide, molybdenum dioxide, or the like.

(9) The first winding sections N1, N2, N3 are anchored above front side VS on insulating layer I and cover through hole FZ almost completely except for small gaps S1, S2, S3 between the individual windings W1, W2, W3, W4.

(10) First winding sections N1, N2, N3 are followed by second winding sections VA, which run essentially perpendicular with respect to front side VS, and second winding sections VA are followed by third winding sections HA, which run essentially in a coplanar manner with respect to front side VS at a distance from first winding sections N1, N2, N3. An opening O of coil configuration SA is thereby defined. The material of the second and third winding sections VA, HA is made of a material that differs from the low-dimensional conductive material, for example from metal such as e.g. nickel. Such a coil geometry may be manufactured by deposition processes combined with sacrificial layer processes.

(11) Permanent magnet areas M1, M2, which produce an axial magnetic flux F through coil configuration SA, are configured on the longitudinal ends of coil configuration SA in the direction of coil axis X. These permanent magnet areas M1, M2 may be manufactured by deposition and subsequent structuring of a suitable permanent-magnetic or ferromagnetic material.

(12) If sound SC enters through the through opening K, FZ, then the first winding sections N1, N2, N3 are deflectable by this sound SC, and a corresponding voltage is induced in coil configuration SA, which is able to be tapped at terminal pads P1, P2, which are connected to the ends of coil configuration SA. In the present example, the first, second and third winding sections N1, N2, N3, VA, HA are configured in strip-shaped fashion so as to be able to cover a large area with small gaps S1, S2, S3. This increases the sensitivity of the sound transducer system.

(13) A corresponding evaluation ASIC is not shown and may also be integrated on the substrate for example or in a separate chip.

(14) FIG. 2 shows a schematic vertical cross-sectional view of a micromechanical sound transducer system according to a second specific embodiment of the present invention.

(15) In the second specific embodiment as shown in FIG. 2, substrate 1 is configured in accordance with the first specific embodiment, coil configuration SA being indicated only schematically, and is attached on a carrier TR having a carrier opening TL, the carrier opening being in fluid communication with the through opening so that sound SC is able to reach coil configuration SA from outside through carrier opening TL and through opening K, FZ. A cover D is attached on carrier TR above front side VS, which cover defines an enclosed back volume BV above front side VS. Such a back volume BV is advantageous in order to reduce unwanted damping effects. The permanent magnetization likewise points in the direction of coil axis X.

(16) In this specific embodiment, magnet device M1, M2 is integrated into a wall DW of cover D in the direction of coil axis X, for example by insertion of a suitable ferromagnetic material.

(17) Additionally, there is an indication in substrate 1 of the second specific embodiment of a continuous contact DK with a bond area B on the front side of substrate 1, which may be used to establish en electrical connection to carrier TR.

(18) FIG. 3 shows a schematic vertical cross-sectional view of a micromechanical sound transducer system according to a third specific embodiment of the present invention.

(19) In the third specific embodiment as shown in FIG. 3, the insulating layer is designated by reference symbol I. It forms a diaphragm area M over through hole FZ of through opening K, FZ, which covers through hole FZ. In this specific embodiment, first winding sections N1, N2, N3 are supported by diaphragm area M, diaphragm area M being deflectable by sound SC. This makes it possible to generate more ram pressure for the sound SC. In this specific embodiment, third winding sections HA of windings W2, W3 are additionally provided with perforations L1 through L6 for sound to pass through, which reduces the ram pressure forming behind diaphragm region M so that the dynamics are increased.

(20) In other respects, the third specific embodiment is configured identically to the first specific embodiment.

(21) Although the present invention was described completely above with reference to the exemplary embodiments, it is not limited to these, but may be modified in numerous ways.

(22) Particularly the shown geometries and materials are only exemplary and may be varied nearly at will depending on the application.

(23) Although in the above specific embodiments, the magnet device is made of a ferromagnetic material, it is not limited to this, but could also be implemented by an electromagnetic coil device.

(24) The present invention is also not limited to microphones, but is also applicable to other sound transducers such as e.g. loudspeakers.