MICROMECHANICAL STRUCTURE AND METHOD FOR MANUFACTURING A MICROMECHANICAL STRUCTURE

• US 20130186200A1
• Filed: 01/16/2013
• Published: 07/25/2013
• Est. Priority Date: 01/23/2012
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Johannes Classen
• Inventors: CLASSEN, Johannes
• Granted Patent: US 9,279,822 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• CPC Class Codes: G01C 19/5747 each sensing mass being connected to a driving mass, e.g. driving frames
• CPC Class Codes: G01C 19/5769 Manufacturing; Mounting; Housings
• CPC Class Codes: G01P 15/02 by making use of inertia forces using solid seismic massesG01P15/14 takes precedence
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0814 for translational movement of the mass, e.g. shuttle type
• CPC Class Codes: G01P 2015/0871 using stopper structures for limiting the travel of the seismic mass
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A micromechanical structure includes: a substrate which has a main plane of extension; and a mass which is movable relative to the substrate, the movable mass being elastically suspended via at least one coupling spring. A first subregion of the movable mass is situated, at least partially, between the substrate and the coupling spring along a vertical direction which is essentially perpendicular to the main plane of extension.

Claims

1. A micromechanical structure, comprising:

a substrate which has a main plane of extension; and

a mass which is movable relative to the substrate, the movable mass being elastically suspended via at least one coupling spring, wherein at least one first subregion of the movable mass is at least partially situated between the substrate and the coupling spring along a vertical direction which is essentially perpendicular to the main plane of extension.

2. The micromechanical structure as recited in claim 1, wherein the micromechanical structure has a first functional layer and a second functional layer, the first and second functional layers being offset relative to one another along the vertical direction in such a way that, along the vertical direction, the first functional layer is situated between the substrate and the second functional layer, and wherein the first subregion is provided in the first functional layer, and the coupling spring is provided in the second functional layer.

3. The micromechanical structure as recited in claim 2, wherein a second subregion of the movable mass is provided in the second functional layer, and wherein the coupling spring engages directly at the second subregion.

4. The micromechanical structure as recited in claim 3, wherein the first subregion and the second subregion mutually overlap in an overlap area along the vertical direction, and wherein the first and the second functional layers in the overlap area are one of (i) directly fixedly connected to one another, or (ii) indirectly fixedly connected to one another via an intermediate layer.

5. The micromechanical structure as recited in claim 1, wherein the micromechanical structure has fixed electrodes which extend parallel to the main plane of extension and are situated between the first subregion and the substrate along the vertical direction, and wherein the fixed electrodes and the first subregion form a plate capacitor structure.

6. The micromechanical structure as recited in claim 2, wherein:

the micromechanical structure has at least one stop spring which is (i) connected to the substrate and (ii) provided in the second functional layer;

one stop region of the first subregion of the movable mass provided in the first functional layer is situated between the stop spring and the substrate along the vertical direction; and

the stop spring is situated at a distance from the movable mass.

7. The micromechanical structure as recited in claim 6, wherein the micromechanical structure is part of an acceleration sensor, and the movable mass includes a seismic mass which is deflectable with respect to the substrate due to external acceleration forces.

8. The micromechanical structure as recited in claim 6, wherein:

the micromechanical structure is part of a yaw rate sensor;

the movable mass includes at least one of (i) a Coriolis element which is deflectable relative to the substrate by Coriolis forces when a yaw rate is present, and (ii) a drive element which is induced to vibrate by a drive mechanism and which is coupled via at least one drive spring to a Coriolis element which is deflectable relative to the substrate by Coriolis forces when a yaw rate is present, the drive element being coupled to the substrate with the aid of the coupling springs.

9. The micromechanical structure as recited in claim 6, wherein the micromechanical structure is part of an actuator, and wherein the movable mass includes an actuator which is drivable by a drive mechanism.

10. A method for manufacturing a micromechanical structure, comprising:

in a first step, providing a substrate;

in a second step, providing the first functional layer and providing a first subregion of a movable mass in the first functional layer; and

in a third step, providing a second functional layer and providing a coupling spring in the second functional layer in such a way that the first subregion is situated between the substrate and the coupling spring along a vertical direction which is essentially perpendicular to a main plane of extension of the substrate, and wherein the movable mass is elastically suspended via the coupling spring.

11. The method as recited in claim 10, wherein at least one of:

(i) a second subregion of the movable mass is provided in the second functional layer in the third step; and

(ii) in an intermediate step carried out between the second step and the third step, an intermediate layer is provided on the first functional layer, and the intermediate layer is structured in such a way that the first subregion and the second subregion of the movable mass are rigidly connected to one another in an overlap area via the intermediate layer.