Method for shaped optical MEMS components with stressed thin films

• US 6,706,202 B1
• Filed: 09/28/2000
• Issued: 03/16/2004
• Est. Priority Date: 09/28/2000
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Maeda, Patrick Y., Chua, Christopher L., Peeters, Eric, Sun, Decai, Rosa, Michel A., Lemmi, Francesco
• Primary Examiner(s): Beck, Shrive P.
• Assistant Examiner(s): OLSEN, ALLAN W
• Application Number:
  US09/672,386
• Time in Patent Office: 1,265 Days
• Field of Search: 216/2, 216/24, 216/26, 216/40, 427/162
• US Class Current: 216/24
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81C 1/00666 Treatments for controlling internal stress or strain in MEMS structures
• CPC Class Codes: B81C 2201/017 Methods for controlling internal stress of deposited layers not provided for in B81C2201/0164 - B81C2201/0169

Abstract

A method is disclosed for making shaped optical moems components with stressed thin films. In particular, stressed thin films are used to make mirror structures.

Claims

1. A method for making a shaped optical MEMS component with stressed thin films comprising:

providing a substrate having a face;

depositing a sacrificial layer on said face;

placing a lift-off mask over said sacrificial layer to define said optical MEMS component;

depositing a metal alloy stress gradient layer over said sacrificial layer;

removing said lift-off mask and portions of said stress gradient layer residing on said lift-off mask; and

,

releasing said stress gradient layer from said sacrificial layer to make said optical MEMS component.

2. The method of claim 1 wherein said shaped optical MEMS component is a MEMS spherical mirror.

3. The method of claim 1 wherein said shaped optical MEMS component is a MEMS cylindrical mirror.

4. The method of claim 1 wherein the depositing of the metal alloy stress gradient layer further comprises the operation of:

depositing multiple layers to form the metal alloy stress gradient layer, each layer having a different inherent stress.

5. The method of claim 1 wherein the metal alloy stress gradient layer includes MoCr material.

6. The method of claim 4 wherein the different inherent stress in each layer is induced by depositing each layer at a different pressure.

7. The method of claim 6 wherein the pressure increases with each layer of the metal alloys stress gradient layer that is deposited.

8. The method of claim 1 wherein a sputtering process is used to deposit each layer in the metal alloy stress gradient layer.

9. A method for making a shaped optical MEMS component with stressed thin films comprising:

providing a substrate having a face;

depositing a sacrificial layer on said face;

placing a lift off mask over said sacrificial layer to define said optical MEMS component;

depositing a metal alloy stress gradient layer over said sacrificial layer;

removing said lift-off mask; and

,

releasing said stress gradient layer from said sacrificial layer to make said optical MEMS component.

10. The method of claim 9 wherein the pressure is altered during the sputtering process to induce different stresses in different layers of the stress gradient layer.