Micromechanical component and method for producing a micromechanical component

• US 20090079037A1
• Filed: 08/01/2008
• Published: 03/26/2009
• Est. Priority Date: 09/20/2007
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Weber, Heribert, Hausner, Ralf
• Granted Patent: US 7,705,413 B2
• Time in Patent Office: Days
• US Class Current: 257/618
• CPC Class Codes: B81B 7/0051 between the package lid and the substrate
• CPC Class Codes: B81C 2203/0118 Bonding a wafer on the substrate, i.e. where the cap consists of another wafer
• CPC Class Codes: B81C 2203/019 characterised by the material or arrangement of seals between parts

Abstract

A micromechanical component, in particular a micromechanical sensor, having a first wafer and a second wafer is provided, the first wafer having at least one structural element, and the second wafer having at least one mating structural element, and, in addition, the structural element and the mating structural element are designed in such a way that a relative displacement of the first wafer relative to the second wafer parallel to a main extension plane of the first wafer essentially leads to compressive loading or tensile loading between the structural element and the mating structural element.

Claims

1. A micromechanical component, which is a micromechanical sensor, comprises:

a first wafer having at least one structural element; and

a second wafer having at least one mating structural element;

wherein the structural element and the mating structural element are configured so that a relative displacement of the first wafer with respect to the second wafer parallel to a main extension plane of the first wafer essentially leads to one of compressive loading and tensile loading between the structural element and the mating structural element.

2. The micromechanical component of claim 1, wherein the first wafer includes an additional structural element, and the second wafer includes an additional mating structural element, which are configured so that a relative displacement of the first wafer with respect to the second wafer perpendicular to the main extension plane essentially leads to one of compressive loading and tensile loading between the further structural element and the further mating structural element.

3. The micromechanical component of claim 1, wherein at least one of the first wafer and the second wafer includes a functional region, which is surrounded by a sealing region.

4. The micromechanical component of claim 1, wherein a joining medium is provided in at least one of the sealing region and in at least one subregion of at least one of at least one structural element and at least one mating structural element, the joining medium being provided to seal the functional region, and providing a mechanically stable connection between the first wafer and the second wafer.

5. The micromechanical component of claim 1, wherein at least one of the structural element and the additional structural element are configured at least partially as a groove, and at least one of the mating structural element and the additional mating structural element are at least partially configured as a stud structure, which is provided so as to at least partially engage with the groove, and wherein at least one of the groove and the stud structure completely surrounds the functional region in a main extension plane.

6. The micromechanical component of claim 1, wherein the functional region has at least one displaceable element, the displaceable element being provided so as to be displaceable with respect to at least one of the first wafer and the second wafer, and at least one of the first wafer and the second wafer includes a stop, which functions as mechanical delimitation of a maximum deflection of the displaceable structure perpendicular to the first main extension plane.

7. The micromechanical component of claim 1, wherein one of (i) the first wafer has a functional layer, and the second wafer has a cap wafer, and (ii) the first wafer has a cap wafer, and the second wafer has a functional layer.

9. The method of claim 6, wherein following the first method operation, applying and patterning a second protective layer on the cap wafer, wherein the second protective layer is removed following the etching anew, wherein an additional etching operation of the cap wafer is implemented thereafter to form the stud structure, and wherein the first protective layer is removed prior to the joining operation.

10. The method of claim 6, wherein a joining medium is applied on the stud structure before the joining.

11. The method of claim 6, wherein the joining medium is a solder, which is one of an electrically conductive solder and an electrically non-conductive glass solder, the solder having a thermal expansion coefficient that is adapted to a thermal expansion coefficient of silicon, wherein the joining medium is Sealglas, and wherein the glass is applied in a screen-printing process and glazed in a prebake process.

12. The method of claim 6, wherein a partial method operation is inserted between the applying and the patterning of the first protective layer on the cap wafer, wherein a third protective layer is applied and patterned, and wherein following the etching anew, the third protective layer is removed.

13. The method of claim 6, wherein following one of the additional etching and the removal of the first layer method operation, the cap wafer is provided with a fourth protective layer on a first surface and a second surface, the surfaces each having an additional main extension plane parallel to the first main extension plane, and through-etchings are one of etched and trenched in the cap wafer, the etching operation being implemented from at least one of a first direction lying perpendicular to the first main extension plane, and a second direction lying anti-parallel to the first direction, the extension of the through-etchings parallel to the first direction being identical to the extension of the cap wafer parallel to the first direction.

14. The micromechanical component of claim 1, wherein at least one of the first wafer and the second wafer includes a functional region, which is surrounded by a sealing region, the functional region being completely surrounded by the sealing region in the main extension plane.

15. The micromechanical component of claim 1, wherein the joining medium is Sealglas.

16. The micromechanical component of claim 1, wherein one of (i) the first wafer has a functional layer, and the second wafer has a cap wafer, and (ii) the first wafer has a cap wafer, and the second wafer has a functional layer, which is of a semiconductor material.

17. The micromechanical component of claim 1, wherein one of (i) the first wafer has a functional layer, and the second wafer has a cap wafer, and (ii) the first wafer has a cap wafer, and the second wafer has a functional layer, which is of a semiconductor material of silicon.

8. A method for making a micromechanical component, the method comprising:

applying and patterning a first protective layer on a cap wafer;

etching the cap wafer;

at least partially removing the first protective layer;

etching anew the cap wafer; and

joining the cap wafer to a functional layer so that a stud structure engages with a groove of a functional layer and a stable mechanical connection is produced in at least one subregion of a groove surface;

wherein the micromechanical component is a micromechanical sensor, and includes;

a first wafer having at least one structural element; and

a second wafer having at least one mating structural element;

wherein the structural element and the mating structural element are configured so that a relative displacement of the first wafer with respect to the second wafer parallel to a main extension plane of the first wafer essentially leads to one of compressive loading and tensile loading between the structural element and the mating structural element.