Mirror device with an anti-stiction layer

• US 7,880,952 B2
• Filed: 05/02/2008
• Issued: 02/01/2011
• Est. Priority Date: 05/03/2007
• Status: Active Grant

• Current Assignee: Ignite USA (Ignite)
• Original Assignee: Olympus Corporation, Silicon Quest Kabushiki-Kaisha
• Inventors: Watanabe, Kazuhiro, Maeda, Yoshihiro, Ichikawa, Hirotoshi, Ishii, Fusao
• Primary Examiner(s): Mack; Ricky L
• Assistant Examiner(s): Tra; Tuyen Q
• Application Number:
  US12/151,186
• Publication Number:
  US 20090231667A1
• Time in Patent Office: 1,005 Days
• Field of Search: 359/290, 359/291, 359/292, 359/295, 359/298, 359/220, 359/223, 359/224, 359/320
• US Class Current: 359/290
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G03B 21/28 Reflectors in projection beam in illumination beam G03B21/2066
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A micromirror device includes an elastic hinge for supporting a mirror on a substrate, and an address electrode for deflecting the mirror. The device further includes a protective layer and an oriented monolayer laid to cover a stopper also functioning as an address electrode provided below the mirror and between the mirror and the substrate.

Claims

1. A micromirror device, comprising:

an elastic hinge composed of a conductive material extends from a substrate for supporting a mirror thereon;

an address electrode for receiving an electrical signal to deflect the mirror;

a protective layer covers and insulates the address electrode; and

an oriented monolayer composed of a compound of a plurality of oriented mono-molecules covers the back surface of the mirror, and the protective layer as an anti-stiction layer.

2. The device according to claim 1, wherein:

the oriented monolayer is composed oriented mono-molecules of a halogenated alkyl silicide or an alkyl silicide.

3. The device according to claim 1, wherein:

the oriented monolayer is composed of a compound of two or more oriented monomolecules of coupled molecules of different number of at least carbon or halogen.

4. The device according to claim 1, wherein:

the oriented monolayer is composed of a combination of one or two or more of a group of oriented mono-molecules consist of perfluorodecyltrichlorosilane, dichlorodimethylsilane, vinyl trimethoxy silane, octadecyltrichlorosinan, undecenyltrichlorosilane, decyltrichlorosilane, fluorooctatrichlorosilane, perfluorodecyldimethylchlorosilane, and

perfluorooctyldimethylchlorosilane.

5. The device according to claim 1, wherein:

the oriented monolayer is composed of a plurality of monolayers each comprises plurality of oriented mono-molecules.

6. The device according to claim 1, wherein:

the oriented monolayer is composed of a plurality of monolayers each comprises plurality of oriented mono-molecules wherein an end portion coupled to the substrate of a first layer is halogenated silane, and an opposite end portion of the first layer comprising of hydrogen, hydroxyl, or carboxyl.

7. The device according to claim 1, wherein:

the oriented monolayer is composed of a plurality of monolayers;

a first and second layers are composed of different materials; and

an end portion of the material of the second layer coupled to the oriented monolayer film of the first layer is halogenated silane or carboxyl, and an opposite end portion is —

CF₃.

8. The device according to claim 1, wherein:

the oriented monolayer is composed of a plurality of monolayers each comprises plurality of oriented mono-molecules; and

an end portion of a first oriented monolayer is alkyl silicide, and an opposite end portion is hydrogen or halogenated carbon as hydroxyl.

9. The device according to claim 1, wherein:

the oriented monolayer is composed of a plurality of monolayers each comprises plurality of oriented mono-molecules; and

a first and a second layers are composed of different materials; and

the second layer is composed of CF₃(CF₂)_x(CH₂)_ySi(CH₃)_nCl_3-n(0≦

n≦

2).

10. The device according to claim 1, comprising:

a mirror array comprises a plurality of mirrors each having substantially a square shape having a width about 11 μ

m or less, and a gap of 0.55 μ

m or less between two adjacent mirrors.

11. The device according to claim 1, wherein:

a distance between a lower surface of the mirror and a top surface of the protective layer is 1 μ

m or less.

12. A method for producing a micromirror device, comprising:

forming a plurality of elastic hinges extended from a substrate wherein each of said hinges supports a mirror thereon with two of adjacent mirrors having a gap of approximately 0.55 μ

m or less and wherein said hinge is composed of a conductive material having a width greater than the gap between two of said adjacent mirrors;

forming a stopper on a top surface of said substrate adjacent to the hinge for stopping the mirror at a maximum deflection angle;

forming an address electrode to receive a signal for deflecting the mirror; and

forming a protective layer to cover and insulate the address electrode; and

forming an oriented monolayer composed of a compound of a plurality of oriented mono-molecules to cover the bottom surface of the mirror, the stopper, and the protective layer as an anti-stiction layer for preventing a stiction between the bottom surface of the mirror, the stopper and the address electrode.

13. A projection device comprising:

a micromirror device comprising;

a mirror supported on a deformable hinge extended from a substrate for deflecting to different angles for reflecting an incident light to an ON light state and an OFF light state;

an address electrode disposed on a top surface of the substrate below the mirror to receive mirror control signals for generating a Coulomb force for deflecting the mirror to said different angles;

a stopper disposed near the hinge for stopping the mirror at a maximum deflection angle; and

a drive circuit for generating and transmitting the mirror control signals to the address electrode, wherein

the stopper is covered by two or more different types of oriented mono-layers composed of a compound with molecules containing six halogenated carbon or less.