Structure of a micro electro mechanical system and the manufacturing method thereof

• US 7,291,921 B2
• Filed: 03/29/2004
• Issued: 11/06/2007
• Est. Priority Date: 09/30/2003
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Lin, Wen-Jian
• Primary Examiner(s): Smith; Matthew
• Assistant Examiner(s): Stark; Jarrett J
• Application Number:
  US10/810,660
• Publication Number:
  US 20050078348A1
• Time in Patent Office: 1,317 Days
• Field of Search: 257/678, 257/773, 257/415, 257/80, 438/52, 438/69, 359/254, 359/245, 359/291
• US Class Current: 257/773
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81C 1/00801 Avoid alteration of functional structures by etching, e.g. using a passivation layer or an etch stop layer B81C1/00595, B81C1/00468 take precedence
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A structure of a micro electro mechanical system and a manufacturing method are provided, the structure and manufacturing method is adapted for an optical interference display cell. The structure of the optical interference display cell includes a first electrode, a second electrode and posts. The second electrode comprises a conductive layer covered by a material layer and is arranged about parallel with the first electrode. The support is located between the first plate and the second plate and a cavity is formed. In the release etch process of manufacturing the structure, the material layer protects the conductive layer from the damage by an etching reagent. The material layer also protects the conductive layer from the damage from the oxygen and moisture in the air.

Claims

1. A pre-release structure configured to form a micro electro mechanical system upon removal of a sacrificial layer through a structure release etch process, said micro electro mechanical system suitable to use on an optical interference display cell, the pre-release structure comprising:

a first electrode;

a second electrode comprising;

a first material layer; and

a conductor layer comprising a light reflective surface facing the first electrode and set directly on the first material layer and approximately in parallel to the first electrode, wherein the first material layer is positioned between the conductor layer and the first electrode;

a sacrificial layer positioned between the first material layer and the first electrode, the sacrificial layer selected from the group consisting of dielectric material, metal material, and silicon material; and

a supporter configured to separate the first electrode from the first material layer to form a cavity upon structure release etching;

wherein the conductor layer is susceptible to etching by an etchant suitable to remove the sacrificial layer and wherein the first material layer is adapted to protect the second electrode from etching when the sacrificial layer is removed using the etchant

wherein the optical interference display cell formed after removal of the sacrificial layer is configured to interferometrically reflect light entering the cavity and contacting the light reflective surface.

2. The pre-release structure of claim 1, wherein the material of the sacrificial layer is selected from the group consisting of metal material or silicon material.

3. The pre-release structure of claim 1, further comprising a second material layer covering the second electrode.

4. The pre-release structure of claim 3, wherein the material of the second material layer is selected from the group consisting of silicon material, dielectric material, transparent conductor material, macromolecule polymer, metal oxide and any arbitrary combination thereof.

5. The pre-release structure of claim 4, wherein the second material layer is a silicon material that is poly-silicon or amorphous silicon.

6. The pre-release structure of claim 4, wherein the second material layer is a dielectric material that is silicon oxide, silicon nitride, or silicon oxynitride.

7. The pre-release structure of claim 4, wherein the second material layer is a transparent conductor material that is indium tin oxide, indium zinc oxide, or indium oxide.

8. The pre-release structure of claim 3, wherein the thickness of the second material layer is about several angstroms to 2000 angstrom.

9. The pre-release structure of claim 3, wherein the thickness of the second material layer is preferably about 200 angstrom to 1000 angstrom.

10. The pre-release structure of claim 1, wherein the material of the first material layer is selected from the group consisting of silicon material, dielectric material, transparent conductor material, macromolecule polymer, metal oxide and any arbitrary combination thereof.

11. The pre-release structure of claim 10, wherein the first material layer is a silicon material that is poly-silicon or amorphous silicon.

12. The pre-release structure of claim 10, wherein the first material layer is a dielectric material that is silicon oxide, silicon nitride, or silicon oxynitride.

13. The pre-release structure of claim 10, wherein the first material layer is a transparent conductor material that is indium tin oxide, indium zinc oxide, or indium oxide.

14. The pre-release structure of claim 1, wherein the thickness of the first material layer is about several angstroms to 2000 angstrom.

15. The pre-release structure of claim 1, wherein the thickness of the first material layer is preferably about 200 angstrom to 1000 angstrom.

16. The pre-release structure of claim 1, wherein the material forming the supporter is selected from the group consisting of one or more of positive photoresists, negative photoresists, acrylic resins, and epoxy resins.

17. The pre-release structure of claim 1, wherein the material of forming the conductor layer is metal material.

18. The pre-release structure of claim 1, wherein the second electrode is a movable electrode.

19. The pre-release structure of claim 1, wherein the sacrificial layer is amorphous silicon.

20. A structure of a micro electro mechanical system comprising:

a first electrode;

a second electrode comprising;

a first material layer; and

a conductor layer set on the first material layer and approximately in

parallel to the first electrode; and

a supporter configured to separate the first electrode from the first material layer to form a cavity;

a second material layer set on the second electrode; and

a spacer set on the sidewalls of the second electrode and the first material layer;

wherein the first material layer is adapted to protect the second electrode from etching when a sacrificial layer between the first electrode and the first material layer is removed through a structure release etch process to form the cavity.

21. The structure of a micro electro mechanical system of claim 20, wherein the material of the spacer is selected from the group consisting of silicon material, dielectric material, transparent conductor material, macromolecule polymer, metal oxide and any arbitrary combination thereof.

22. The structure of a micro electro mechanical system of claim 21, wherein the material of the spacer is a silicon material that is poly-silicon or amorphous silicon.

23. The structure of a micro electro mechanical system of claim 21, wherein the material of the spacer is a dielectric material that is silicon oxide, silicon nitride, or silicon oxynitride.

24. The structure of a micro electro mechanical system of claim 21, wherein the material of the spacer is a transparent conductor material that is indium tin oxide, indium zinc oxide, or indium oxide.

25. The structure of a micro electro mechanical system of claim 21, wherein the material of the spacer is a macromolecule polymer that is paraffin or a macromolecule material that can be coated by vapor.

26. A structure of a micro electro mechanical system, comprising:

a first electrode;

a second electrode comprising;

a first material layer; and

a conductor layer set on the first material layer and approximately in

parallel to the first electrode; and

a supporter configured to separate the first electrode from the first material layer to form a cavity;

wherein the first material layer is adapted to protect the second electrode from etching when a sacrificial layer between the first electrode and the first material layer is removed through a structure release etch process to form the cavity;

wherein the first material layer is a macromolecule polymer that is paraffin or a macromolecule material that can be coated by vapor.

27. A structure of a micro electro mechanical system, comprising:

a first electrode;

a second electrode comprising;

a first material layer; and

a conductor layer set on the first material layer and approximately in parallel to the first electrode;

a supporter configured to separate the first electrode from the first material layer to form a cavity; and

a second material layer covering the second electrode;

wherein the first material layer is adapted to protect the second electrode from etching when a sacrificial layer between the first electrode and the first material layer is removed through a structure release etch process to form the cavity;

wherein the second material layer is a macromolecule polymer that is paraffin or a macromolecule material that can be coated by vapor.

28. A pre-release structure configured to form a micro electro mechanical system upon removal of a sacrificial layer through a structure release etch process, said micro electro mechanical system suitable to use on an optical interference display cell, the pre-release structure comprising:

a first electrode;

a second electrode comprising a light reflective surface facing the first electrode and set approximately in parallel to the first electrode;

a material layer directly contacting the light reflective surface;

a sacrificial layer positioned between the material layer and the first electrode, the sacrificial layer selected from the group consisting of dielectric material, metal material, and silicon material; and

a supporter configured to separate the first electrode from the material layer to form a cavity upon structure release etching;

wherein the second electrode is susceptible to etching by an etchant suitable to remove the sacrificial layer and wherein the material layer is adapted to protect the second electrode from etching when the sacrificial layer is removed using the etchant

wherein the optical interference display cell formed after removal of the sacrificial layer is configured to interferometrically reflect light entering the cavity and contacting the light reflective surface.

29. The pre-release structure of claim 28, wherein the material of the sacrificial layer is selected from the group consisting of metal material and silicon material.

30. The pre-release structure of claim 28, wherein the material of the material layer is selected from the group consisting of silicon material, dielectric material, transparent conductor material, macromolecule polymer, metal oxide and any arbitrary combination thereof.

31. The pre-release structure of claim 30, wherein the material of the material layer is a silicon material that is poly-silicon or amorphous silicon.

32. The pre-release structure of claim 30, wherein the material of the material layer is a dielectric material that is silicon oxide, silicon nitride, or silicon oxynitride.

33. The pre-release structure of claim 30, wherein the material of the material layer is a transparent conductor material that is indium tin oxide, indium zinc oxide, or indium oxide.

34. The pre-release structure of claim 30, wherein the material of the material layer is a macromolecule polymer that is paraffin or a macromolecule material that can be coated by vapor.

35. The pre-release structure of claim 28, wherein the thickness of the material layer is about several angstroms to 2000 angstrom.

36. The pre-release structure of claim 28, wherein the thickness of the material layer is preferably about 200 angstrom to 1000 angstrom.

37. The pre-release structure of claim 28, wherein the material forming the supporter is selected from the group consisting of one or more of positive photoresists, negative photoresists, acrylic resins, and epoxy resins.

38. The pre-release structure of claim 28, wherein the second electrode is a movable electrode.

39. The pre-release structure of claim 28, wherein the sacrificial layer is amorphous silicon.