MICROMECHANICAL COMPONENT AND MANUFACTURING METHOD FOR A MICROMECHANICAL COMPONENT

• US 20120167681A1
• Filed: 11/03/2011
• Published: 07/05/2012
• Est. Priority Date: 01/05/2011
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Reinmuth, Jochen
• Granted Patent: US 8,850,891 B2
• Time in Patent Office: Days
• US Class Current: 73/504.12
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 3/0078 Constitution or structural means for improving mechanical properties not provided for in B81B3/007 - B81B3/0075
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 15/18 in two or more dimensions
• 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 29/49826 Assembling or joining

Abstract

A micromechanical component having a fixing point and a seismic weight, which is connected to the fixing point by at least one spring and is made at least partially out of a first material, the first material being a semiconductor material, the seismic weight being additionally made out of at least one second material, and the second material having a higher density than the first material. In addition, a manufacturing method for a micromechanical component is provided, having the steps of forming a seismic weight at least partially out of a first material, the first material being a semiconductor material, connecting the seismic weight to a fixing point of the micromechanical component, using at least one spring, and forming the seismic weight from the first material and at least one second material, which has a higher density than the first material.

Claims

1. A micromechanical component, comprising:

a fixing point; and

a seismic weight connected to the fixing point by at least one spring, the seismic weight being made at least partially out of a first material, the first material being a semiconductor material, and being additionally made out of at least one second material, the second material having a higher density than the first material.

2. The micromechanical component as recited in claim 1, wherein the second material includes at least one metal.

3. The micromechanical component as recited in claim 2, wherein the second material includes at least one of hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, and copper.

4. The micromechanical component as recited in claim 1, wherein the seismic weight includes at least a first partial weight made out of the first material and a second partial weight at least partially made out of the second material, and the second partial weight is connected to the first partial weight by at least one spring structure.

5. The micromechanical component as recited in claim 1, wherein the micromechanical component includes a substrate, and the seismic weight has an inner side oriented towards the substrate and an outer side oriented away from the substrate, and the seismic weight includes finger structures situated between the inner side and the outer side, the finger structures containing at least the second material, and longitudinal center axes of the finger structures being oriented parallelly to at least one of the inner side and to the outer side.

6. The micromechanical component as recited in claim 5, wherein heights of the finger structures extend from the inner side to the outer side.

7. The micromechanical component as recited in claim 5, wherein the finger structures are formed from the second material in such a manner that the first material is present in them as at most a residual element.

8. The micromechanical component as recited in claim 5, wherein a partial outer surface of the outer side is made of the first material.

9. A method of manufacturing a micromechanical component, comprising:

forming a seismic weight out of a first material and at least one second material, the first material being a semiconductor material, the at least one second material having a higher density than the first material; and

connecting the seismic weight to a fixing point of the micromechanical component via at least one spring.

10. The method as recited in claim 9, wherein the forming of the seismic weight from the first material and the second material includes:

patterning a starting structure out of a layer of the first material; and

at least one of;

i) coating at least one upper surface of the starting structure with the second material, and ii) carrying out a substitution reaction for replacing at least an outer layer of the starting structure with the second material.

11. The method as recited in claim 10, wherein the starting structure is patterned out of the layer of the first material using a passivation layer formed on an upper side of the layer of the first material as a mask, and the upper side is covered in such a manner by the passivation layer during the at least one of the coating of the at least one upper surface of the starting structure, and the substitution reaction, that at least one of the substitution reaction occurs selectively at the at least one outer layer exposed by the patterning-out of the starting structure, and that the at least one upper surface of the starting structure formed during the patterning-out of the starting structure or during the substitution reaction is selectively coated.

12. The method as recited in claim 10, wherein WF₆ and hydrogen are deposited for coating the at least one upper surface of the starting structure.

13. The method as recited in claim 10, wherein WF₆ is deposited for carrying out the substitution reaction.

14. The method as recited in claim 10, wherein at least one trench passing through the layer of the first material is formed while patterning out the starting structure.

15. The manufacturing method as recited in claim 10, wherein finger structures are formed during the patterning out of the starting structure, and the finger widths of two adjacent finger structures are formed to be greater than a distance between the two adjacent finger structures.