MICROMECHANICAL SYSTEM INCLUDING A SENSITIVE ELEMENT AND ASSOCIATED MANUFACTURING METHOD

• US 20180237290A1
• Filed: 02/02/2018
• Published: 08/23/2018
• Est. Priority Date: 02/17/2017
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Haug, Daniel, Baer, Hans-Peter, Schwarz, Mike, Senz, Volkmar
• Granted Patent: US 10,442,681 B2
• Time in Patent Office: Days
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81B 3/0072 For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers
• CPC Class Codes: B81B 7/0016 Protection against shocks or vibrations, e.g. vibration damping
• CPC Class Codes: B81C 1/00666 Treatments for controlling internal stress or strain in MEMS structures
• CPC Class Codes: B81C 2201/0132 Dry etching, i.e. plasma etching, barrel etching, reactive ion etching [RIE], sputter etching or ion milling
• 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 2203/032 Gluing

Abstract

A micromechanical system including a sensitive element, the system including a first area in which the sensitive element is situated, and a second area which at least partially surrounds the first area. Furthermore, the system includes a holding element having an elastic property, which joins the first area to the second area, and a joining material, with the aid of which the second area may be joined to a substrate. A spacing area is provided between the first area and the second area. The joining material extends into the spacing area so that a possible movement of the first area caused by the elastic property of the holding element is limited.

Claims

1. A micromechanical system provided with a sensitive element, comprising:

a first area in which the sensitive element is situated;

a second area which at least partially surrounds the first area;

a holding element having an elastic property, which joins the first area to the second area; and

a joining material, with the aid of which the second area may be joined to a substrate, a spacing area being provided between the first area and the second area, and the joining material extending into the spacing area and limiting a possible movement of the first area caused by the elastic property of the holding element.

2. The micromechanical system as recited in claim 1, wherein the second area extends beneath and laterally around the first area, and the spacing area includes a first portion beneath the first area, and the joining material extends into the first portion of the spacing area.

3. The micromechanical system as recited in claim 1, wherein the spacing area includes at least one second portion, which is situated laterally of the first area and extends between a front side of the system and a lower side of the first area, and the holding element is situated in the second portion of the spacing area and surrounds the first area on its side.

4. The micromechanical system as recited in claim 1, wherein the holding element is formed integrally with a material of the first area and of the second area.

5. The micromechanical system as recited in claim 1, wherein the second area includes through-holes, which are situated beneath the first area and extend between a lower side of the second area and a lower side of the spacing area.

6. The micromechanical system as recited in claim 1, wherein a portion of the joining material at least one of:

(i) is introduced into the spacing area with the aid of the through-holes, and (ii) extends through the through-holes into the spacing area.

7. The micromechanical system as recited in claim 1, wherein the joining material is formed at least partially from a soft adhesive material, so that the joining material in the spacing area acts as a damping material during a deflection of the first area occurring relative to the second area.

8. The micromechanical system as recited in claim 1, wherein the joining material is formed at least partially from a hard adhesive material, so that the joining material in the spacing area acts as at least one of a spacer and a stop for the first area during a deflection of the first area occurring relative to the second area.

9. The micromechanical system as recited in claim 1, wherein the first area includes a diaphragm provided with the sensitive element and a cavity abutting the diaphragm.

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

providing a wafer including a sensor core area in which a sensitive element is situated;

carrying out a front side trench process so that, laterally of the sensor core area, a front side trench is formed in the wafer in which a web is situated;

carrying out a rear side trench process so that one or multiple rear side recesses are formed in the wafer;

carrying out an exposure process in which, on an end area of the rear side recesses in the wafer, an exposure of a lower side of the sensor core area and of the web is achieved by non-directional etching;

providing the wafer with a joining material; and

introducing the joining material through the rear side recesses, which act as through-holes, into the exposed area on the lower side of the sensor core area.

11. The method as recited in claim 10, wherein an adhesive material is used as joining material.

12. The method as recited in claim 10, wherein the joining material is introduced into the exposed area at least one of:

(i) by utilizing a capillary effect, (ii) by a contact pressure of the wafer on a substrate, and (iii) by a temperature effect.

13. The method as recited in claim 12, wherein the joining material is applied as a film to the wafer lower side, and the wafer is pressed with the wafer lower side, together with the applied film, onto the substrate.

14. The method as recited in claim 12, wherein the joining material is applied to the substrate, and the wafer is pressed with the wafer lower side onto the substrate provided with the joining material.