MEMS device and method of forming a MEMS device

• US 7,776,631 B2
• Filed: 11/04/2005
• Issued: 08/17/2010
• Est. Priority Date: 05/05/1994
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Miles, Mark W.
• Primary Examiner(s): Fulk; Steven J
• Application Number:
  US11/267,819
• Publication Number:
  US 20060261330A1
• Time in Patent Office: 1,747 Days
• Field of Search: 438/29, 257/432, 257/E23.114, 359/291
• US Class Current: 438/29
• 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: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/34 by control of light from an independent source
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

Light in the visible spectrum is modulated using an array of modulation elements, and control circuitry connected to the array for controlling each of the modulation elements independently, each of the modulation elements having a surface which is caused to exhibit a predetermined impedance characteristic to particular frequencies of light. The amplitude of light delivered by each of the modulation elements is controlled independently by pulse code modulation. Each modulation element has a deformable portion held under tensile stress, and the control circuitry controls the deformation of the deformable portion. Each deformable element has a deformation mechanism and an optical portion, the deformation mechanism and the optical portion independently imparting to the element respectively a controlled deformation characteristic and a controlled modulation characteristic. The deformable modulation element may be a non-metal. The elements are made by forming a sandwich of two layers and a sacrificial layer between them, the sacrificial layer having a thickness related to the final cavity dimension, and using water or an oxygen based plasma to remove the sacrificial layer.

Claims

1. A method of forming a device, the method comprising:

providing a substrate comprising at least one conductive layer;

forming an insulating layer over the at least one conductive layer;

forming a protective layer over the insulating layer;

forming an opening through the protective layer to the insulating layer;

after forming the opening through the protective layer, further forming the opening through the insulating layer to the at least one conductive layer;

forming a removable layer within the opening; and

removing the removable layer from the opening.

2. The method of claim 1, additionally comprising forming a reflective layer over the substrate.

3. The method of claim 1, wherein the insulating material comprises silicon dioxide.

4. The method of claim 1, wherein the insulating material comprises silicon nitride.

5. The method of claim 1, wherein the protective layer comprises a photoresisting material.

6. The method of claim 1, additionally comprising forming a template layer over the protective layer.

7. The method of claim 6, additionally comprising forming a photoresist layer over the template layer.

15. The method of claim 1, further comprising forming an interferometric cavity in the opening.

8. A method of forming a micro-mirror device, the method comprising:

providing a substructure including a base material and at least one conductive layer formed on a first side of the base material;

forming a layer of an insulating material over the at least one conductive layer of the substructure;

forming a protective layer comprising a material resistant to an etch process above the layer of the insulating material;

forming a reflective element above the insulating material;

forming an opening through the insulating material to the etch resistant material;

after forming the opening through the insulating material, further forming the opening to the at least one conductive layer of the substructure;

forming a removable layer within the opening; and

removing the removable layer from the opening.

9. The method of claim 8 substantially removing the insulating material between the reflective element and the conductive layer.

10. The method of claim 8, wherein the insulating material comprises silicon dioxide.

11. The method of claim 8, wherein the insulating material comprises silicon nitride.

12. The method of claim 8, wherein the protective layer comprises a photoresisting material.

13. The method of claim 8, additionally comprising forming a template layer over the protective layer.

14. The method of claim 13, additionally comprising forming a photoresist layer over the template layer.

16. The method of claim 8, further comprising forming an interferometric cavity in the opening.