Micromechanical component and manufacturing method for a micromechanical component

• US 9,038,466 B2
• Filed: 03/27/2012
• Issued: 05/26/2015
• Est. Priority Date: 03/30/2011
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Reinmuth, Jochen
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US13/431,613
• Publication Number:
  US 20120248931A1
• Time in Patent Office: 1,155 Days
• Field of Search: 735/143.2, 324/661, 361/280
• US Class Current: 73/514.32
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: G01L 9/0005 using variations in capacitance G01L9/0072 takes precedence
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0831 the mass being of the paddle type having the pivot axis between the longitudinal ends of the mass, e.g. see-saw configuration
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine

Abstract

A micromechanical component is described having a substrate which has at least one stator electrode fixedly mounted with respect to the substrate, a movable mass having at least one actuator electrode fixedly mounted with respect to the movable mass, and at least one spring via which the movable mass is displaceable. The movable mass is structured from the substrate with the aid of at least one separating trench, at least one outer stator electrode spans at least one section of the at least one separating trench and/or of the movable mass, the at least one actuator electrode protrudes between the at least one outer stator electrode and the substrate, and at least one inner stator electrode protrudes between the at least one actuator electrode and the substrate. A related manufacturing method is also described for a micromechanical component.

Claims

1. A micromechanical component, comprising:

a substrate having at least one stator electrode which is fixedly mounted with respect to the substrate;

a movable mass having at least one actuator electrode which is fixedly mounted with respect to the movable mass; and

at least one spring via which the movable mass is connected to the substrate so that the movable mass is displaceable with respect to the substrate at least from a first position into a second position, wherein the movable mass is structured from the substrate with at least one separating trench;

at least one outer stator electrode spanning at least one section of the at least one separating trench or the movable mass, wherein the at least one actuator electrode protrudes at least into a first space between the at least one outer stator electrode and the substrate; and

at least one inner stator electrode protruding at least into a second space between the at least one actuator electrode and the substrate.

2. The micromechanical component of claim 1, wherein the at least one outer stator electrode is connected to the substrate with at least one stator supporting component situated in the first space.

3. The micromechanical component of claim 2, wherein a row-column pattern of the actuator supporting components is offset with respect to a row-column pattern of the stator supporting components so that one of the stator supporting components protrudes into a rectangle composed of four actuator supporting components, at an equal distance from the four actuator supporting components, and one of the actuator supporting components protrudes into a rectangle composed of four stator supporting components, at an equal distance from the four stator supporting components.

4. The micromechanical component of claim 1, further comprising at least one integrated sensor wherein the integrated sensor is provided at the substrate.

5. The micromechanical component of claim 1, wherein the micromechanical component includes an outer layer made of conductive material which includes the at least one outer stator electrode, a middle layer made of conductive material which includes the at least one actuator electrode, an inner layer made of conductive material which includes the at least one inner stator electrode, and at least one buffer area.

6. The micromechanical component of claim 5, wherein the buffer area includes at least one insulating material provided between the outer layer and the middle layer.

7. The micromechanical component of claim 5, wherein the buffer area includes at least one insulating material provided between the middle layer and the inner layer.

8. The micromechanical component of claim 5, wherein the buffer area includes at least one conductive material provided between the outer layer and the middle layer.

9. The micromechanical component of claim 5, wherein the buffer area includes at least one conductive material provided between the middle layer and the inner layer.

10. The micromechanical component of claim 1, wherein the movable mass is tiltable with respect to the substrate about a rotational axis which extends along the at least one spring, and wherein the rotational axis divides the movable mass into a first partial mass having a first weight, and a second partial mass having a second weight which is less than the first weight.

11. The micromechanical component of claim 10, wherein the first partial mass and the second partial mass each include a connecting web and multiple finger webs situated at the associated connecting web, the first partial mass also including an additional mass situated at the ends of its finger webs, facing away from its connecting web.

12. The micromechanical component of claim 11, wherein the finger webs contact actuator supporting components at actuator contact areas, have widenings located at the actuator contact areas of at least two actuator supporting components, and have a narrower design between two adjacent actuator contact areas.

13. The micromechanical component of claim 1, wherein at least one of (i) the at least one outer stator electrode, and (ii) the at least one actuator electrode include(s) gridded areas composed of jagged strands which are at least one of kinked and bent at right angles.

14. The micromechanical component of claim 1, wherein the at least one actuator electrode is connected to the movable mass with at least one actuator supporting component situated in the second space.

15. The micromechanical component of claim 14, wherein a row-column pattern of the actuator supporting components is offset with respect to a row-column pattern of the stator supporting components so that one of the stator supporting components protrudes into a rectangle composed of four actuator supporting components, at an equal distance from the four actuator supporting components, and one of the actuator supporting components protrudes into a rectangle composed of four stator supporting components, at an equal distance from the four stator supporting components.

16. The micromechanical component of claim 1, further comprising at least one evaluation device wherein the at least one evaluation device is provided at the substrate.

17. A sensor device, comprising:

a micromechanical component, including;

a substrate having at least one stator electrode which is fixedly mounted with respect to the substrate;

a movable mass having at least one actuator electrode which is fixedly mounted with respect to the movable mass; and

at least one spring via which the movable mass is connected to the substrate so that the movable mass is displaceable with respect to the substrate at least from a first position into a second position, wherein the movable mass is structured from the substrate with at least one separating trench;

at least one outer stator electrode spanning at least one section of the at least one separating trench or the movable mass, wherein the at least one actuator electrode protrudes at least into a first space between the at least one outer stator electrode and the substrate; and

at least one inner stator electrode protruding at least into a second space between the at least one actuator electrode and the substrate; and

an evaluation device which is configured to ascertain a first variable concerning a first capacitance of a first capacitor formed from the at least one outer stator electrode and the at least one actuator electrode, to ascertain a second variable concerning a second capacitance of a second capacitor formed from the at least one inner stator electrode and the at least one actuator electrode, to determine information by taking into account the ascertained first variable and the ascertained second variable, and to output the determined information.

18. The sensor device of claim 17, wherein the determined information is concerning acceleration exerted on the movable mass.

19. The sensor device of claim 17, wherein the determined information is concerning pressure exerted on the movable mass.

20. The sensor device of claim 17, wherein the determined information is concerning a magnetic field in a region of a coil which is fixedly mounted with respect to the movable mass.

21. A manufacturing method for a micromechanical component, the method comprising:

connecting a movable mass via at least one spring to a substrate so that the movable mass is displaceable with respect to the substrate at least from a first position into a second position;

fixedly mounting at least one stator electrode with respect to the substrate; and

fixedly mounting at least one actuator electrode with respect to the movable mass;

structuring at least the movable mass from the substrate with the aid of at least one separating trench;

arranging at least one outer stator electrode so that the at least one outer stator electrode spans at least one section of the separating trench or the movable mass,

arranging the at least one actuator electrode so that the at least one actuator electrode protrudes at least into a first space between the at least one outer stator electrode and the substrate; and

arranging at least one inner stator electrode so that the at least one inner stator electrode protrudes at least into a second space between the at least one actuator electrode and the substrate.

22. The manufacturing method of claim 21, further comprising:

performing the following prior to structuring the movable mass from the substrate;

covering at least a partial surface of the substrate with an insulating layer;

forming an inner layer made of conductive material, including the at least one inner stator electrode, on the insulating layer;

at least partially covering the inner layer with a first sacrificial layer;

forming a middle layer made of conductive material, including the at least one actuator electrode, on the first sacrificial layer;

at least partially covering the middle layer with a second sacrificial layer; and

forming an outer layer made of conductive material, including the at least one outer stator electrode, on the second sacrificial layer.

23. The manufacturing method of claim 22, further comprising:

performing a first etching operation for removing at least partial regions of the second sacrificial layer, of the first sacrificial layer, and of the insulating layer;

performing a second etching operation for forming at least one trench in at least one region of the substrate which is exposed in the at least one first etching operation;

forming at least one protective layer in the at least one formed trench, the at least one side wall of the at least one trench being covered by the at least one protective layer, and the at least one protective layer being removed from the at least one base surface of the at least one trench; and

performing an isotropic third etching operation so that at least the movable mass is structured from the substrate.

24. A manufacturing method for a sensor device, the method comprising:

manufacturing a micromechanical component by performing the following;

connecting a movable mass via at least one spring to a substrate so that the movable mass is displaceable with respect to the substrate at least from a first position into a second position;

fixedly mounting at least one stator electrode with respect to the substrate; and

fixedly mounting at least one actuator electrode with respect to the movable mass;

structuring at least the movable mass from the substrate with the aid of at least one separating trench;

arranging at least one outer stator electrode so that the at least one outer stator electrode spans at least one section of the separating trench or the movable mass;

arranging the at least one actuator electrode so that the at least one actuator electrode protrudes at least into a first space between the at least one outer stator electrode and the substrate; and

arranging at least one inner stator electrode so that the at least one inner stator electrode protrudes at least into a second space between the at least one actuator electrode and the substrate; and

providing an evaluation device which is configured, during subsequent operation of the sensor device, to ascertain a first variable concerning a first capacitance of a first capacitor formed from the at least one outer stator electrode and the at least one actuator electrode, to ascertain a second variable concerning a second capacitance of a second capacitor formed from the at least one inner stator electrode and the at least one actuator electrode, and to determine and output information concerning at least one of an acceleration exerted on the movable mass, a pressure exerted on the movable mass, or a magnetic field in a region of a coil which is fixedly mounted with respect to the movable mass, taking the ascertained first variable and the ascertained second variable into account.