Method of forming a flexible MEMS device

Patent metadata

Field	Value
Publication number	US-11261084-B2
Application number	US-202016907123-A
Country	US
Kind code	B2
Filing date	Jun 19, 2020
Priority date	Jun 22, 2019
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

A method of forming a microelectromechanical device wherein a beam of the microelectromechanical device may deviate from a resting to an engaged or disengaged position through electrical biasing. The microelectromechanical device comprises a beam disposed above a first RF conductor and a second RF conductor. The microelectromechanical device further comprises at least a center stack, a first RF stack, a second RF stack, a first stack formed on a first base layer, and a second stack formed on a second base layer, each stack disposed between the beam and the first and second RF conductors. The beam is configured to deflect downward to first contact the first stack formed on the first base layer and the second stack formed on the second base layer simultaneously or the center stack, before contacting the first RF stack and the second RF stack simultaneously.

First claim

What is claimed is:

1. A method for forming a microelectromechanical device, comprising:
forming one or more bottom electrodes on a backplane comprising at least two RF conductors;
depositing a bottom dielectric layer over the backplane and the one or more bottom electrodes;
etching one or more openings in the bottom dielectric layer;
depositing a first base layer and a second base layer onto the one or more openings in the bottom dielectric layer;
depositing a plurality of stacks on at least the first and second base layers, above the at least two RF conductors, and between the at least two RF conductors;
depositing a first spun layer over an entire surface of all of the layers previously deposited;
depositing a first dielectric layer on the first spun layer;
removing at least two areas of the first dielectric layer disposed above the at least two RF conductors;
depositing at least two beam contact layers on the at least two removed areas of the first dielectric layer;
depositing a bottom beam layer over the at least two beam contact layers and the first dielectric layer;
depositing a second spun layer on the bottom beam layer;
depositing a top beam layer above the second spun layer;
depositing a third spun layer over the top beam layer;
depositing a partial cavity layer above the third spun layer;
depositing a roof dielectric layer over the partial cavity layer;
etching one or more release holes through the roof dielectric layer;
removing the first spun layer, the second spun layer, and the third spun layer through the one or more release holes; and
depositing a seal layer above the roof dielectric layer and within the one or more release holes.

2. The method of claim 1 , further comprising:
depositing an oxide layer over the one or more bottom electrodes prior to depositing the bottom dielectric layer; and
etching one or more second portions in the bottom dielectric layer prior to depositing the plurality of stacks.

3. The method of claim 2 , wherein depositing the plurality of stacks comprises depositing a stack onto each of the etched one or more second portions of the bottom dielectric layer.

4. The method of claim 1 , further comprising:
forming a plurality of vias in the second spun layer prior to depositing the top beam layer; and
depositing the top beam layer within the plurality of vias to form a plurality of links between the top beam layer and the bottom beam layer.

5. The method of claim 1 , wherein the etching of the bottom dielectric layer is a timed etch process.

6. The method of claim 1 , wherein each of the plurality of stacks comprises more than one layer.

7. The method of claim 6 , wherein each of the plurality of stacks includes at least one layer of ruthenium.

8. The method of claim 6 , wherein each of the plurality of stacks includes a layer of titanium nitride.

9. The method of claim 1 , further comprising:
etching a portion of a top layer of each of the plurality of stacks and a portion of the beam contact layer after removing the first spun layer, the second spun layer, and the third spun layer.

10. A microelectromechanical device, comprising:
a backplane comprising at least two RF conductors;
a plurality of bottom electrodes disposed on the backplane;
a bottom dielectric layer disposed on the plurality of bottom electrodes, the bottom dielectric layer comprising at least two openings;
a first base layer and a second base layer disposed on at least two openings of the bottom dielectric layer;
a first stack disposed on the first base layer, the first stack having a first height;
a second stack disposed on the second base layer, the second stack having the first height;
at least two RF stacks disposed above the at least two RF conductors, the at least two RF stacks each having a second height less than the first height of the first and second stacks;
a center stack disposed between the at least two RF stacks, the center stack having the second height;
a beam contact layer disposed above the at least two RF stacks;
a bottom beam layer disposed over the beam contact layer;
a top beam layer disposed above the bottom beam layer;
a partial cavity layer disposed above the top beam layer; and
a seal layer disposed above the partial cavity layer.

11. The microelectromechanical device of claim 10 , wherein a portion of the partial cavity layer forms a top electrode.

12. The microelectromechanical device of claim 10 , wherein the center stack is configured to contact the bottom beam layer prior to the first stack, the second stack and the at least two RF stacks contacting the bottom beam layer.

13. The microelectromechanical device of claim 10 , wherein at least a layer of each of the stacks comprises ruthenium.

14. The microelectromechanical device of claim 10 , wherein the first stack and the second stack are configured to contact the bottom beam layer prior to the at least two RF stacks contacting the bottom beam layer.

15. The microelectromechanical device of claim 10 , further comprising:
a plurality of links disposed between the bottom beam layer and the top beam layer.

Assignees

• Qorvo Us Inc

Inventors

• Van Kampen Robertus Petrus
• Barron Lance
• Renault Mickael
• Ghosh Dastider Shibajyoti
• Muyango Jacques Marcel
• Knipe Richard L

Classifications

• B81C1/00444 Primary

  Surface micromachining, i.e. structuring layers on the substrate · CPC title

• B81B2207/11

  Structural features, others than packages, for protecting a device against environmental influences · CPC title

• B81C1/00158

  Diaphragms, membranes (manufacture process for semi-permeable inorganic membranes B01D67/0039) · CPC title

• B81C1/00349

  Creating layers of material on a substrate · CPC title

• B81B3/0067

  Mechanical properties · CPC title