Micro-electro-mechanical device and method for making the same

Patent metadata

Field	Value
Publication number	US-9518884-B2
Application number	US-201314049850-A
Country	US
Kind code	B2
Filing date	Oct 9, 2013
Priority date	Oct 22, 2012
Publication date	Dec 13, 2016
Grant date	Dec 13, 2016

Abstract

The invention provides a micro-electro-mechanical device which includes a substrate, an electrode, and a diaphragm. The electrode includes plural vent holes. The diaphragm is disposed above and in parallel to the electrode, to form a capacitive sensor with the electrode. The diaphragm includes plural ribs protruding upward and/or downward from the diaphragm; the ribs are respectively disposed in correspondence to the plural vent holes and do not overlap nor contact the electrode. A method for making the micro-electro-mechanical device is also provided according to the present invention.

First claim

What is claimed is:

1. A micro-electro-mechanical device, comprising:
a substrate, a first metal layer above the substrate, a via layer above the first metal layer, and a second metal layer above the via layer;
an electrode, including a plurality of vent holes; and
a diaphragm, including a planar layer and a plurality of ribs, wherein the planar layer is disposed above and in parallel to the electrode to form a capacitive sensor with the electrode, and the ribs protrude upward and/or downward from the planar layer such that the ribs are respectively disposed in correspondence to the vent holes, wherein the ribs are smaller than and within the vent holes from a top view having a direction normal to the substrate, such that the ribs do not contact the electrode and do not overlap the electrode from the top view;
wherein each of the ribs at least includes the via layer and the second metal layer which are located in correspondence to the vent holes and are stacked such that a whole interface between the via layer and the second metal layer is in parallel to the planar layer, and the via layer and the second metal layer are different layers from the planar layer and do not belong to a part of the planar layer.

2. The micro-electro-mechanical device of claim 1 , wherein the ribs are made of a conductive material including metal, metallic compound, conductive polymer, polysilicon or a combination thereof.

3. The micro-electro-mechanical device of claim 1 , wherein the electrode includes a portion of the first metal layer and a portion of the substrate.

4. The micro-electro-mechanical device of claim 1 , wherein the via layer is made of a conductive material and includes an internal space which is a hollow space or filled with a dielectric material.

5. The micro-electro-mechanical device of claim 1 , wherein at least one of the ribs includes a bottom opening or a top opening.

6. The micro-electro-mechanical device of claim 1 , wherein the ribs near a center region of the diaphragm have a relatively higher density than the ribs near a peripheral region of the diaphragm.

7. The micro-electro-mechanical device of claim 1 , wherein the vent holes near a center region of the electrode have a relatively larger size than the vent holes near a peripheral region of the electrode.

8. The micro-electro-mechanical device of claim 1 , further including a spacer to define an area of the diaphragm; and a supporting ring encompassing the diaphragm and disposed between a periphery of the diaphragm and the spacer.

9. The micro-electro-mechanical device of claim 8 , wherein the supporting ring encompasses the diaphragm in a continuous form or the supporting ring encompasses the diaphragm with regular or irregular intervals.

10. A method of making micro-electro-mechanical device, comprising:
providing a substrate, a first metal layer above the substrate, a via layer above the first metal layer, and a second metal layer above the via layer;
forming an electrode having a plurality of vent holes;
forming a spacer on the substrate; and
forming a diaphragm which includes a planar layer and a plurality of ribs, wherein the planar layer is connected to the spacer so that the diaphragm forms a capacitor sensor with the electrode, and the ribs protrude upward and/or downward from the planar layer such that the ribs are respectively disposed in correspondence to the vent holes, wherein the ribs are smaller than and within the vent holes from a top view having a direction normal to the substrate, such that the ribs do not contact the electrode and do not overlap the electrode from the top view;
wherein each of the ribs at least includes the via layer and the second metal layer which are located in correspondence to the vent holes and are stacked such that a whole interface between the via layer and the second metal layer is in parallel to the planar layer, and the via layer and the second metal layer are different layers from the planar layer and do not belong to a part of the planar layer.

11. The method of claim 10 , wherein the ribs are made of a conductive material including metal, metallic compound, conductive polymer, polysilicon, or a combination thereof.

12. The method of claim 10 , wherein the electrode includes a portion of the first metal layer and a portion of the substrate.

13. The method of claim 10 , wherein the via layer is made of a conductive material and includes an internal space which is a hollow space or filled with a dielectric material.

14. The method of claim 10 , wherein at least one of the ribs includes a bottom opening or a top opening.

15. The method of claim 10 , wherein the ribs near a center region of the diaphragm have a relatively higher density than the ribs near a peripheral region of the diaphragm.

16. The method of claim 10 , wherein the vent holes near a center region of the electrode have a relatively larger size than the vent holes near a peripheral region of the electrode.

17. The method of claim 10 , wherein the spacer defines an area of the diaphragm, and the method further comprises: forming a supporting ring encompassing the diaphragm and disposed between a periphery of the diaphragm and the spacer.

18. The method of claim 17 , wherein the supporting ring encompasses the diaphragm in a continuous form or the supporting ring encompasses the diaphragm with regular or irregular intervals.

Assignees

• Tsai Ming-Han
• Pixart Imaging Inc

Inventors

• Tsai Ming-Han

Classifications

• H04R19/00

  Electrostatic transducers · CPC title

• B81B3/007

  For controlling stiffness, e.g. ribs · CPC title

• G01L9/0072

  using variations in capacitance · CPC title

• B81B2201/0257

  Microphones or microspeakers · CPC title

• H04R2201/003

  Mems transducers or their use · CPC title