Manufacture method for micromechanical devices

• US 6,099,132 A
• Filed: 06/07/1995
• Issued: 08/08/2000
• Est. Priority Date: 09/23/1994
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Kaeriyama, Toshiyuki
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US08/483,777
• Time in Patent Office: 1,889 Days
• Field of Search: 359/226, 359/291, 359/872, 359/873, 156/463, 156/644, 156/654, 216/2
• US Class Current: 359/872
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A process for manufacturing micromechanical devices. The process includes the step of covering the activation circuitry (201) and those parts of the device that come in contact with moving parts with a pad film (202). The pad film prevents frictional wear and sticking of the moving parts, and can prevent electrical shorts between different parts of the activation circuitry. Additionally, the pad film can prevent particulates from interfering with the operation of the device.

Claims

1. A method for manufacturing a digital micromirror device, wherein said method comprises:

forming activation circuitry upon a semiconductor wafer, wherein said activation circuitry includes surfaces with a first bias and surfaces with a second bias;

depositing an inorganic pad film upon said activation circuitry, wherein said pad film acts as an insulator between said surfaces having said first bias and said surfaces having said second bias;

building a spacer layer upon said pad film;

cutting vias into said spacer layer;

laying a first metal layer upon said spacer layer such that said first metal fills said vias;

depositing a second metal layer upon said first metal layer and patterning and etching said second layer to form mirrors and hinges; and

removing said spacer layer such that said mirror is held at said second bias and is suspended over said activation circuitry by said hinges and when activated contacts said surfaces having said second bias.

2. The method of claim 1 wherein said inorganic material is a nitride.

3. The method of claim 1 wherein said inorganic material is an oxide.

4. A micromechanical device comprising:

activation circuitry formed upon a semiconductor wafer;

posts formed adjacent said activation circuitry;

a mirror suspended from hinges on said posts, such that said mirror is operable to be activated by elements of said activation circuitry that have a first bias and will make contact with some elements of said activation circuitry held at a common second bias with said mirror when said mirror deflects; and

an inorganic pad film formed upon at least part of said activation circuitry such that said inorganic pad film acts as an insulator between said elements at said first bias, said elements at said second bias and said mirror.