Yokeless hidden hinge digital micromirror device with double binge layer

• US 7,411,713 B2
• Filed: 08/06/2006
• Issued: 08/12/2008
• Est. Priority Date: 01/31/2002
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: DiCarlo, Anthony
• Primary Examiner(s): Cherry; Euncha P
• Application Number:
  US11/462,707
• Publication Number:
  US 20060268390A1
• Time in Patent Office: 737 Days
• Field of Search: 359223-226, 359/290, 359/291, 359/871, 359/872
• US Class Current: 359/224.1
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

A micromirror array 110 fabricated on a semiconductor substrate 11. The array 110 is comprised of four operating layers 12, 13, 14, 15. An addressing layer 12 is fabricated on the substrate. A raised electrode layer 13 is spaced above the addressing layer by an air gap. A hinge layer 14 is spaced above the raised electrode layer 13 by another air gap. A mirror layer 15 is spaced over the hinge layer 14 by a third air gap.

Claims

1. A method of forming an array of micromirror elements, comprising the steps of:

depositing a first spacer layer on a substrate;

patterning the first spacer layer to define lower hinge support vias and raised electrode vias;

depositing a raised electrode layer over the first spacer layer;

patterning the raised electrode layer to form at least two raised electrodes associated with each micromirror elements;

depositing a second spacer layer over the patterned raised electrodes;

patterning the second spacer layer to form hinge support vias over the lower hinge support vias;

depositing a hinge layer over the second spacer layer;

patterning the hinge layer to form at least one hinge associated with each micromirror element;

depositing a third spacer layer over the hinge layer;

patterning the third spacer layer to define mirror support vias;

depositing a mirror layer over the third spacer layer;

patterning the mirror layer to form an array of micromirrors; and

removing the first, second, and third spacer layers.

2. The method of claim 1, wherein the hinge layer is further patterned to form at least two spring tips under each mirror.

3. The method of claim 1, wherein the patterning is accomplished by photolithographic processes.

4. The method of claim 1, wherein each mirror is rectangular in shape, wherein the hinge is under the diagonal axis of the mirror such that the mirror tilts around the diagonal axis.