MEMS and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-11186478-B2
Application number	US-201916550823-A
Country	US
Kind code	B2
Filing date	Aug 26, 2019
Priority date	Mar 7, 2017
Publication date	Nov 30, 2021
Grant date	Nov 30, 2021

Abstract

A MEMS includes a substrate having a cavity, and a moveable element arranged in the cavity, the moveable element including a first electrode, a second electrode and a third electrode that is arranged between the first electrode and the second electrode and is fixed in an electrically insulated manner from the same at discrete areas. The moveable element is configured to perform a movement along a movement direction in a substrate plan in response to an electric potential between the first electrode and the third electrode or in response to an electric potential between the second electrode and the third electrode. A dimension of the third electrode perpendicular to the substrate plane is lower than a dimension of the first electrode and a dimension of the second electrode perpendicular to the substrate plane.

First claim

The invention claimed is:

1. A MEMS comprising:
a substrate comprising a cavity;
a moveable element arranged in the cavity, the moveable element comprising a first electrode connected to the substrate, a second electrode connected to the substrate and a third electrode that is arranged between the first electrode and the second electrode and is connected to the substrate, the third electrode being fixed with the first electrode and the second electrode in an electrically insulated manner with a fixation at discrete areas;
wherein the moveable element is configured to perform a movement along a movement direction in a substrate plane in response to an electric potential between the first electrode and the third electrode or in response to an electric potential between the second electrode and the third electrode;
wherein the first electrode and the second electrode are under mechanical tension in a state without the electric potential so that the first electrode and the second electrode move away from the third electrode as a result of separating the fixation or are held with respect to the third electrode by means of a multi-stable structure.

2. The MEMS according to claim 1 , wherein the first electrode and the second electrode are connected to the substrate via spring elements, wherein the spring elements provide the mechanical tension.

3. The MEMS according to claim 2 , wherein the spring elements are spring elements under tensile stress, or wherein the spring elements are multi-stable elements.

4. The MEMS according to claim 1 , wherein the first electrode and the second electrode comprise a dimension perpendicular to a movement direction of the moveable elements of more than 150 μm.

5. The MEMS according to claim 1 , wherein a dimension of the third electrode perpendicular to the substrate plane is smaller than a dimension of the first electrode and a dimension of the second electrode perpendicular to the substrate plane.

6. A MEMS including:
a substrate comprising a cavity;
a moveable element arranged in the cavity, the moveable element comprising a first electrode, a second electrode and a third electrode that is arranged between the first electrode and the second electrode and is fixed in an electrically insulated manner from the same at discrete areas;
wherein the moveable element is configured to perform a movement along a movement direction in a substrate plane in response to an electric potential between the first electrode and the third electrode or in response to an electric potential between the second electrode and the third electrode;
wherein a dimension of the third electrode perpendicular to the substrate plane is smaller than a dimension of the first electrode and a dimension of the second electrode perpendicular to the substrate plane.

7. The MEMS according to claim 6 , wherein the dimension of the third electrode perpendicular to the substrate plane is smaller by at least 2% than the dimension of the first electrode and the dimension of the second electrode perpendicular to the substrate plane.

8. The MEMS according to claim 6 , wherein the first electrode and the second electrode comprise an overhang with respect to the third electrode along a positive and a negative direction perpendicular to the substrate plane.

9. The MEMS according to claim 6 , wherein the first electrode is connected to the substrate via a tensioned first spring element, and wherein the second electrode is connected to the substrate via a tensioned second spring element.

10. The MEMS according to claim 6 , wherein a distance between the first electrode and the substrate and between the second electrode and the substrate along a direction perpendicular to the movement direction is less than 1 μm.

11. The MEMS according to claim 6 , wherein a fixation between the first electrode and the third electrode or between the second electrode and the third electrode at the discrete areas includes at least one of:
mechanical latching;
electrostatic sticking;
surface forces;
surface forces during a drying process;
electrostatic attraction;
thermal activation of an interface between two surfaces;
fixation by subsequent deposition of a thin layer; and
chemical adhesive connection.

12. The MEMS according to claim 6 , wherein an insulation layer is arranged at least at one of the first electrode, the second electrode and the third electrode.

13. The MEMS according to claim 6 , wherein an aspect ratio of a distance between the first electrode and the third electrode and a dimension of the first electrode along a direction perpendicular to the movement direction is larger than 100; or wherein an aspect ratio of a distance between the second electrode and the third electrode and a dimension of the second electrode along the direction perpendicular to the movement direction is larger than 100.

14. The MEMS according to claim 6 , configured to provide an electrostatic force in response to the electric potential.

15. The MEMS according to claim 6 , wherein the main sides of the first, second and third electrodes are arranged perpendicular to the substrate plane.

16. A device comprising a MEMS according to claim 6 , the device being configured as an acoustic transducer, a pump, a valve, a dosage system, an acceleration sensor, a rotation rate sensor, a micro-positioning system, a micro-stabilizer or a micro-switch.

17. A MEMS comprising:
a substrate comprising a cavity;
a moveable element arranged in the cavity, the moveable element comprising a first electrode, a second electrode, and a third electrode that is arranged between the first electrode and the second electrode, the third electrode being fixed with the first electrode and the second electrode in an electrically insulated manner with a fixation at discrete areas;
wherein the moveable element is configured to perform a movement along a movement direction in a substrate plane in response to an electric potential between the first electrode and the third electrode or in response to an electric potential between the second electrode and the third electrode;
wherein the first electrode and the second electrode are spaced apart from the third electrode by means of a functional layer and are connected in a mechanically fixed manner at the discrete areas;
wherein an aspect ratio of a distance between the first electrode and the third electrode and a dimension of the first electrode along a direction perpendicular to the movement direction is larger than 100; or wherein an aspect ratio of a distance between the second electrode and the third electrode and a dimension of the second electrode along the direction perpendicular to the movement direction is larger than 100.

18. The MEMS according to claim 17 , wherein at least one of the first electrode, the second electrode and the third electrode is connected to the substrate exclusively indirectly via a neighboring electrode.

Assignees

• Fraunhofer Ges Forschung

Inventors

• Langa Sergiu
• Conrad Holger
• Schimmanz Klaus

Classifications

• B81B3/0056 Primary

  Adjusting the distance between two elements, at least one of them being movable, e.g. air-gap tuning · CPC title

• B81B2203/0315

  Cavities · CPC title

• B81B2201/038

  Microengines and actuators not provided for in B81B2201/031 - B81B2201/037 · CPC title

• B81B3/0013

  Structures dimensioned for mechanical prevention of stiction, e.g. spring with increased stiffness · CPC title

• B81B2203/051

  Translation according to an axis parallel to the substrate · CPC title