Method for manufacturing a mirror device by means of a plurality of sacrificial layers

• US 8,858,811 B2
• Filed: 03/12/2009
• Issued: 10/14/2014
• Est. Priority Date: 11/01/2003
• Status: Active Grant

• Current Assignee: Ignite USA (Ignite), Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Original Assignee: Fred Ishii
• Inventors: Maeda, Yoshihiro, Ishii, Fusao, Watanabe, Kazuhiro, Ichikawa, Hirotoshi
• Primary Examiner(s): AHMED, SHAMIM
• Application Number:
  US12/381,587
• Publication Number:
  US 20090206052A1
• Time in Patent Office: 2,042 Days
• Field of Search: 438/689, 438/706, 438/710, 216/224, 216/41, 216/58, 216/67, 216/2, 216/24
• US Class Current: 216/24
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B

Abstract

A method for manufacturing a device comprising an elastic member on a substrate includes steps of: forming a sacrificial layer by forming a plurality of sacrificial sub-layers on the substrate; forming a plate member in or on the sacrificial layers connected to the substrate and substantially parallel to a top surface of the substrate; and removing the sacrificial sub-layers after forming the plate member by removing the sacrificial sub-layers in an order different from the reverse order of forming the sacrificial sub-layers.

Claims

1. A method for manufacturing a mirror device comprising deflectable mirrors supported on a deflectable hinge extending vertically along approximately a perpendicular direction from a substrate wherein the method comprises:

forming electrodes on the substrate and covering the electrodes with an insulation layer wherein the step of forming the electrodes further comprising a step of forming the electrodes having a horizontally and outwardly extended convex-shaped extension horizontally extended away from the hinge with sharp-edge upper corner with significantly reduced contacting area for contacting and stopping the deflectable mirrors of the mirror device;

forming a first and a second sacrificial layers covering over the insulation layer;

opening a vertical trench penetrating through the first sacrificial layer and the second sacrificial layer and depositing a deflectable hinge material into the vertical trench;

forming the deflectable mirror by depositing a reflective layer directly on top of the second sacrificial layer wherein the reflective layer directly contacting a top surface of the hinge material deposited in the vertical trench; and

removing the first and second sacrificial layers to expose the insulation layer covering the electrodes and the hinge material constituting the vertical hinge for supporting and deflecting the mirror to different deflection angles and stopped by the contacting points of the electrodes contact the deflectable mirrors.

2. The manufacturing method of a mirror device according to claim 1, wherein:

the step of removing first and second sacrificial layers further comprises a step of forming another sacrificial layer covering the hinge or the mirror after removing at least one of the first sacrificial layer or the second sacrificial layer.

3. The manufacturing method of a mirror device according to claim 1, wherein:

the step of forming said first and second sacrificial layers comprising a step of depositing the first sacrificial layer to cover the substrate and an electrode followed by depositing the second sacrificial layer having a planar surface over the first sacrificial layer;

the step of removing the first and second sacrificial layers includes a process of removing the first sacrificial layer after removing the second sacrificial layer.

4. The manufacturing method of a mirror device according to claim 1, wherein:

the step of forming the first and second sacrificial layers further comprising a step of using materials of two different compositions to form said first and second sacrificial layers.

5. The manufacturing method of a mirror device according to claim 1, wherein:

the step of forming the first and second sacrificial layers further comprising a step of using an organic material to form the first sacrificial layer and using an inorganic material to form the second sacrificial layer.

6. The manufacturing method of a mirror device according to claim 1, wherein:

the step of forming the first and second sacrificial layers further comprising a step of using different inorganic materials comprising different additives to form the first and second sacrificial layers.

7. The manufacturing method of a mirror device according to claim 1, wherein:

the step of removing the first and second sacrificial layers further comprising a step of applying etching processes of different etching rates for removing the first and second sacrificial layers.

8. The manufacturing method of a mirror device according to claim 1, wherein:

the step of removing the first and second sacrificial layers further comprising a step of applying a first etchant for removing the first sacrificial layer and a second etchant different from the first etchant for removing the second sacrificial layer.

9. The manufacturing method of a mirror device according to claim 8, wherein:

the step of removing the first and second sacrificial layers includes a step of using an etchant composed of hydrogen fluoride or a compound of hydrogen fluoride for removing the second sacrificial layer.

10. The manufacturing method of a mirror device according to claim 8, wherein:

the step of removing the first and second sacrificial layers further includes a step of applying a dry-etching process for removing the first sacrificial layer by performing a plasma etching process.

11. The manufacturing method of a mirror device according to claim 1, wherein:

the step of removing the first and second sacrificial layers further includes a step of forming an adherence protection layer on the mirror or covering the insulation layer after removing one of the sacrificial layers.

12. The manufacturing method of a mirror device according to claim 1, wherein:

the step of forming the first and second sacrificial layers further includes a step of opening a cavity in the first sacrificial layer for exposing the insulation layer covering over the substrate, and filing the cavity with the second sacrificial layer;

the step of opening the vertical trench further includes a step of opening the vertical trench in the second sacrificial layer and penetrates through the insulation layer to the substrate followed by forming the deflectable hinge material in the vertical trench; and

the step of removing the sacrificial layer further includes a process of removing the second sacrificial layer after removing the first sacrificial layer.

38. The method of manufacturing a device, according to claim 1 wherein:

the step of forming the reflective layer comprises a step of forming the reflective layer directly on top of the sacrificial layer having a length of one side of the movable member in a range substantially between 5 to 10 μ

m.

13. A method of manufacturing a device comprising a movable member supported on a deflectable hinge extending vertically along approximately a perpendicular direction from a substrate, wherein the method comprises:

forming electrodes on the substrate and covering the electrodes with an insulation layer wherein the step of forming the electrodes further comprising a step of forming the electrodes having a horizontally and outwardly extended convex-shaped extension horizontally extended away from the hinge with sharp-edge upper corner with significantly reduced contacting area for contacting and stopping the deflectable mirrors of the mirror device;

forming a first and a second sacrificial layers covering over the insulation layer;

forming a first sacrificial layer covering over the insulation layer disposed on the substrate;

opening a cavity in the first sacrificial layer and the insulation layer exposing a top surface of the substrate;

depositing a layer of deflectable material on a vertical sidewall of the cavity opened in said first sacrificial layer wherein said layer of deflectable material having a bottom lateral portion supported on the substrate;

filling the cavity with a second sacrificial layer;

forming the movable member immediately on top of the first and second sacrificial layers and contacting a top surface of the layer of the deflectable material; and

removing the first sacrificial layer followed by removing the second sacrificial layer for exposing the deflectable hinge supporting the movable member.

14. A method for manufacturing a device comprising a movable member supported on a deflectable hinge extending vertically along approximately a perpendicular direction from, a substrate, wherein the method comprises:

forming electrodes on the substrate and covering the electrodes with an insulation layer wherein the step of forming the electrodes further comprising a step of forming the electrodes having a horizontally and outwardly extended convex-shaped extension horizontally extended away from the hinge with sharp-edge upper corner with significantly reduced contacting area for contacting and stopping the deflectable mirrors of the mirror device;

forming a first sacrificial layer comprising several sub-layers covering over the insulation layer;

opening a vertical trench in the first sacrificial layer and through the insulation layer and filling the vertical trench with a deflectable material having a bottom surface supported on the substrate;

forming a movable member directly on top of the first sacrificial layer with a bottom surface contacting a top surface of the deflectable material filled in the vertical trench;

forming a second sacrificial layer over the movable member; and

removing the first and second sacrificial layers for exposing the deflectable material filling in the vertical trench constituting the hinge supporting the movable member supported on the hinge.

15. The method of claim 14, wherein:

the step of removing the first and second sacrificial layers comprising a step of removing the second sacrificial layer over the movable member after removing the first sacrificial layer.

16. The manufacturing method of a device according to claim 14, wherein:

the step of removing the first and second sacrificial layers comprising a step of removing at least one part of the first sacrificial layer before removing the second sacrificial layer.

17. The manufacturing method of a device according to claim 14, wherein:

the step of removing the first and second sacrificial layers comprises a step of applying a different etchant to remove each of the second and first sacrificial layers composed of a different sacrificial material.

18. The manufacturing method of a device according to claim 14, wherein:

the step of removing the first and second sacrificial layers comprises a step of etching the first sacrificial layer and the second sacrificial layer composed of a different sacrificial materials at a different etching rate.

19. The manufacturing method of a device according to claim 14, wherein:

the step of forming the first and second sacrificial layers comprises a step of forming at least one of the sacrificial layers composed of an inorganic material and adding a different additive to each of the sub-layers of the first and second sacrificial layer.

20. The manufacturing method of a device according to claim 14, wherein:

the step of forming the first and second sacrificial layers comprises a step of forming the first and second sacrificial layer with an inorganic material, and contains one of Na, Li, K, and Al as an additive.

21. The manufacturing method of a device according to claim 14, wherein:

the step of removing the first and second sacrificial layers includes a step of dry-etching the first sacrificial layer by applying a hydrogen fluoride or a compound of hydrogen fluoride.

22. The manufacturing method of a device according to claim 14, wherein:

the step of forming the first sacrificial layers comprises a step of using an organic material to form at least one of the sub-layers of the first sacrificial layer.

23. The manufacturing method of a device according to claim 14, wherein:

the step of forming the second sacrificial layer comprises a step of using an organic material to form the second sacrificial layer.

24. The manufacturing method of a device according to claim 14, wherein:

step of forming the second sacrificial layer comprises a step of using an inorganic material to form second sacrificial layer.

25. The manufacturing method of a device according to claim 14, wherein:

the step of forming the second sacrificial layer includes a step of forming an opening in the second sacrificial layer for exposing a surface of the first sacrificial layer for applying an etchant to the first sacrificial layer.

26. The manufacturing method of a device according to claim 14, wherein:

the step of forming the first sacrificial layer includes a step of opening a cavity having approximately a shape provided to form an array of movable members as a two dimensional matrix.

27. The manufacturing method of a device according to claim 14, wherein:

the step of forming the second sacrificial layer further comprises a step of a cavity in the second sacrificial layer to form each of the movable members adjacent to each other.

28. The manufacturing method of a device according to claim 14, wherein:

the step of forming the first and second sacrificial layers further includes a step of opening a cavity in the first sacrificial layer for exposing the insulation layer, and filing the cavity with the second sacrificial layer;

the step of opening the vertical trench further includes a step of opening the vertical trench in the second sacrificial layer and penetrates through the insulation layer to the substrate followed by forming the deflectable hinge material in the vertical trench; and

the step of removing the sacrificial layer further includes a process of removing the second sacrificial layer after removing the first sacrificial layer.

29. The manufacturing method of a device according to claim 28, wherein:

the step of removing the first and second sacrificial layers includes a step of includes a step of forming an adherence protection layer on the movable member after removing one of the sacrificial layers.

30. The manufacturing method of a device according to claim 28, wherein:

the step of removing the first and second sacrificial layers includes a step of removing the first sacrificial layer after removing the second sacrificial layer.

31. A method of manufacturing a device includes a vertical elastic member extending from a top surface of a substrate for supporting a plate member on top of the vertical elastic member, the method comprising:

forming electrodes on the substrate and covering the electrodes with an insulation layer wherein the step of forming the electrodes further comprising a step of forming the electrodes having a horizontally and outwardly extended convex-shaped extension horizontally extended away from the hinge with sharp-edge upper corner with significantly reduced contacting area for contacting and stopping the deflectable mirrors of the mirror device;

forming a sacrificial layer covering over the insulation layer and opening a vertical trench in the sacrificial layer followed by filling the trench with an elastic material;

forming a plate member directly on top of the sacrificial layer parallel to a surface of the substrate and contacting a top surface of the elastic material filled in the vertical trench and removing the sacrificial layer for exposing the elastic material filled in the trench constituting the vertical elastic member supporting the plate member.

32. The manufacturing method of a device according to claim 31, further comprising:

forming an adherence protection layer on the plate member for protecting the plate member and the step of removing the sacrificial layer further includes a step of removing the adherence protection layer.

33. The manufacturing method of a device according to claim 32, wherein:

the step of removing the adherence protection layer includes a process of dicing the substrate into a plurality of devices before removing the adherence protection layer.

34. The manufacturing method of a device according to claim 32, wherein:

the step of removing the adherence protection layer includes a process of enclosing the substrate in a package before removing the adherence protection layer.

35. A method of manufacturing a device including a vertical elastic member extending from a top surface of a substrate for supporting a movable member on top of the vertical elastic member, the method, comprising:

forming electrodes on the substrate and covering the electrodes with an insulation layer wherein the step of forming the electrodes further comprising a step of forming the electrodes having a horizontally and outwardly extended convex-shaped extension horizontally extended away from the hinge with sharp-edge upper corner with significantly reduced contacting area for contacting and stopping the deflectable mirrors of the mirror device;

forming a sacrificial layer on the substrate including a plurality of sacrificial sub-layers and opening a vertical trench in the sacrificial layer followed by filling the trench with an elastic material;

forming the movable member directly on top of the sacrificial layer and contacting a top surface of the elastic material filled in the vertical trench; and

removing, in an reverse order of forming the sub-layers, the plurality of sacrificial sub-layers after forming the movable member.

36. The manufacturing method of a device according to claim 35, wherein:

the step of removing the plurality of sacrificial sub-layers includes a process of removing the sacrificial sub-layer surrounding the vertical trench filled with the elastic material for exposing the elastic material filled in the trench constituting the vertical elastic member supporting the movable member.

37. A method of manufacturing a device including a vertical elastic member extending from a top surface of a substrate for supporting a movable member on top of the vertical elastic member, the method, comprising:

forming electrodes on the substrate and covering the electrodes with an insulation layer wherein the step of forming the electrodes further comprising a step of forming the electrodes having a horizontally and outwardly extended convex-shaped extension horizontally extended away from the hinge with sharp-edge upper corner with significantly reduced contacting area for contacting and stopping the deflectable mirrors of the mirror device;

forming a sacrificial layer on the substrate including a plurality of sacrificial sub-layers and opening a vertical trench in the sacrificial layer followed by filling the trench with an elastic material;

forming the movable member directly on top of the sacrificial layer and contacting a top surface of the elastic material filled in the vertical trench; and

removing the plurality of sacrificial sub-layers by first etching the sacrificial sub-layer surrounding the vertical trench filled with the elastic material or the sacrificial layer contacting the movable member at a slowest etching rates among etching rates for etching the plurality of the sacrificial sub-layers.

39. The manufacturing method of a device according to claim 37, wherein:

the step of forming the movable member comprises a step of forming the movable member having a length of one side of the movable member in a range substantially between 5 to 10 μ

m.

40. The manufacturing method of a device according to claim 37, wherein:

the step of forming the movable member comprises a step of forming the movable member having a gap substantially in a range between 0.2 to 0.55 μ

m between the adjacent movable members.

41. The manufacturing method of a device according to claim 37, wherein:

the step of forming the elastic member comprises a step of forming the elastic member includes a silicon material.

42. The manufacturing method of a device according to claim 37, wherein:

the step of forming the elastic member comprises a step of forming the elastic member having a width/length ratio greater than or equal to 1.

43. The manufacturing method of a device according to claim 37, wherein:

the step of forming the elastic member comprises a step of forming the elastic member having a length in a range substantially between 0.3 to 1 μ

m.