METHOD OF FABRICATING MEMS DEVICES (SUCH AS IMod) COMPRISING USING A GAS PHASE ETCHANT TO REMOVE A LAYER

• US 20080130089A1
• Filed: 02/14/2008
• Published: 06/05/2008
• Est. Priority Date: 05/05/1994
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Miles, Mark W.
• Granted Patent: US 8,105,496 B2
• Time in Patent Office: Days
• US Class Current: 359/290
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• 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 26/02 for controlling the intensity of light G02B26/004 takes precedence
• 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
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 6/12 of the integrated circuit kind electric integrated circuits H01L27/00
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence
• CPC Class Codes: G02F 1/169 based on orientable non-spherical particles having a common optical characteristic, e.g. suspended particles of reflective metal flakes
• CPC Class Codes: G02F 1/216 using liquid crystals, e.g. liquid crystal Fabry-Perot filters
• CPC Class Codes: G02F 2203/03 scattering
• CPC Class Codes: G06F 3/1431 using a single graphics controller
• CPC Class Codes: G06F 3/1446 display composed of modules, e.g. video walls
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0452 : Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 3/001 : using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/2014 : by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/2074 : using sub-pixels
• CPC Class Codes: G09G 3/2077 : by a combination of two or more gradation control methods
• CPC Class Codes: G09G 3/3466 : based on interferometric effect
• CPC Class Codes: G09G 5/02 : characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: H01Q 9/26 : with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00

Abstract

Improvements in an interferometric modulator that cavity defined by two walls.

Claims

1. A method of fabricating a microelectromechanical structure (MEMS), the method comprising etching a deposited sacrificial layer with a gas phase etchant, wherein the sacrificial layer comprises at least one of molybdenum, tungsten, tantalum, titanium, and germanium.

2. The method of claim 1, wherein the gas phase etchant comprises at least one of XeF₂, BrF₃, ClF₃, BrF₅, and IF₅.

3. The method of claim 1, wherein the MEMS comprises an interferometric modulator in which a wall of the modulator is formed on a substrate and the gas phase etchant etches the sacrificial layer from between the wall and the substrate.

4. The method of claim 1, wherein the MEMS is formed over a substrate which is chemically isolated from the MEMS by an inert film coating.

5. An apparatus comprising:

an unreleased microelectromechanical device comprising at least one thin film disposed, at least in part, on a substrate, wherein the thin film is configured to contact a sacrificial component;

wherein the sacrificial component is etchable by a gas phase etchant;

wherein the substrate is substantially non-etchable by the gas phase etchant, and wherein the sacrificial component comprises at least one of molybdenum, tungsten, tantalum, titanium, and germanium.

6. The apparatus of claim 5, wherein the gas phase etchant comprises at least one of XeF₂, BrF₃, ClF₃, BrF₅, and IF₅.

7. The apparatus of claim 5, wherein the microelectromechanical device comprises an interferometric modulator.

8. A method of forming a movable microelectromechanical device comprising:

disposing a sacrificial layer on a substrate, wherein the sacrificial layer comprises at least one of molybdenum, tungsten, tantalum, titanium, and germanium.

disposing a microelectromechanical structure over the sacrificial layer and the substrate, the microelectromechanical structure comprising at least one thin film; and

etching the sacrificial layer with a gas phase etchant to release the microelectromechanical structure from the sacrificial layer.

9. The method of claim 8, wherein the gas phase etchant comprises at least one XeF₂, BrF₃, ClF₃, BrF₅, and IF₅.

10. The method of claim 8, wherein the microelectromechanical device comprises an interferometric modulator.

11. The method of claim 8, further comprising chemically isolating the substrate from the microelectromechanical device.

12. The method of claim 11, wherein chemically isolating comprises depositing a thin film coating on the substrate.

13. An apparatus comprising:

a substrate configured to be non-etchable by gas phase etching; and

an interferometric modulator disposed, at least in part, on the substrate, wherein the interferometric modulator comprises at least one thin film, wherein the thin film is configured to contact a sacrificial component, and wherein the sacrificial component is configured to define the optical properties of the interference modulator and is etchable with a gas phase etchant.

14. The apparatus of claim 13, wherein the sacrificial component comprises at least one of molybdenum, tungsten, tantalum, titanium, and germanium.

15. The apparatus of claim 13, wherein the gas phase etchant comprises at least one of XeF₂, BrF₃, ClF₃, BrF₅, and IF₅.

16. The apparatus of claim 13, wherein the substrate is configured to be chemically isolated from the interferometric modulator.

17. The apparatus of claim 16, wherein the substrate is chemically isolated from the interferometric modulator by a thin film coating.

18. A method of making an array of microelectromechanical structures on a production line comprising micromachining electromechanical structures on a surface of a glass or plastic substrate that is at least as large as 8″

×

8″

or at least as large as 8″

in diameter.

19. The method of claim 18, in which electronic features are fabricated in conjunction with the microelectromechanical structures.

20. The method of claim 19, in which steps of fabricating the electronic features are overlapping with one or more of the steps of micromachining the structures.

21. The method of claim 19, in which steps of fabricating the electronic features are non-overlapping with the steps of micromachining the structures.

22. The method of claim 18, in which the microelectromechanical structures comprise interferometric modulators.