Method for forming an array of thin film actuated mirrors

• US 5,677,785 A
• Filed: 02/08/1996
• Issued: 10/14/1997
• Est. Priority Date: 04/21/1995
• Status: Expired due to Fees

• Current Assignee: Dongbu Daewoo Electronics Corporation
• Original Assignee: Daewoo Electronics (Government of South Korea)
• Inventors: Chung, Jae-Hyuk, Koo, Myung-Kwon
• Primary Examiner(s): Epps, Georgia Y.
• Assistant Examiner(s): BEY, DAWN MARIE
• Application Number:
  US08/598,478
• Time in Patent Office: 614 Days
• Field of Search: 359/290, 359/291, 359/295, 359/213, 359/214, 359/846, 359/848, 359/849, 359/850, 359/855, 359/224, 359/900, 310/328, 310/366, 437/229, 29/25.35
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means
• CPC Class Codes: Y10S 359/90 Methods

Abstract

An inventive method for the manufacture of an array of M×N thin film actuated mirrors for use in an optical projection system includes the steps of: providing an active matrix; depositing a thin film sacrificial layer; creating an array of empty cavities in the thin film sacrificial layer; depositing an elastic layer; forming an array of conduits in the elastic layer; depositing a second thin film, a thin film electrodisplacive and a first thin film layers, successively; patterning the first thin film, the thin film electrodisplacive, the second thin film and the elastic layers, thereby forming an array of actuated mirror structures; forming a thin film protection layer completely covering each of the actuated mirror structures; removing the thin film sacrificial layer by using an etchant; rinsing away the etchant by using a rinse; removing the rinse by drying in a vacuum or by using a spin drying method; and removing the thin film protection layer, thereby forming the array of M×N thin film actuated mirrors.

Claims

1. A method for the manufacture of an array of M×

N thin film actuated mirrors, wherein M and N are integers, for use in an optical projection system, the method comprising the steps of;

providing an active matrix including a substrate, an array of M×

N connecting terminals and an array of M×

N transistors, wherein each of the connecting terminals is electrically connected to a corresponding transistor in the array of the transistors;

depositing a thin film sacrificial layer on top of the active matrix;

creating an array of M×

N pairs of empty cavities in the thin film sacrificial layer, one of the empty cavities in each pair encompassing one of the connecting terminals;

depositing an elastic layer, made of an insulating material, on top of the thin film sacrificial layer including the empty cavities;

forming an array of M×

N conduits in the elastic layer, each of the conduits extending from top of the elastic layer to top of a corresponding connecting terminal;

depositing a second thin film, a thin film electrodisplacive and a first thin film layers, successively, on top of the elastic layer, wherein the second thin film layer is made of an electrically conducting material, and the first thin film layer is made of an electrically conducting and light reflecting material;

patterning the first thin film, the thin film electrodisplacive, the second thin film and the elastic layers, respectively, into an array of M×

N first thin film electrodes, an array of M×

N thin film electrodisplacive members, an array of M×

N second thin film electrodes and an array of M×

N elastic members, until the thin film sacrificial layer is exposed, thereby forming an array of M×

N actuated mirror structures, each of the actuated mirror structures having a top surface and side surfaces, and including the first thin film electrode, the thin film electrodisplacive member, the second thin film electrode and the elastic member;

forming a thin film protection layer completely covering the top surface and the side surfaces of each of the actuated mirror structures;

removing the thin film sacrificial layer by using an etchant;

rinsing away the etchant by using a first rinse;

removing the first rinse;

And

removing the thin film protection layer, thereby forming the array of M×

N thin film actuated mirrors.

2. The method of claim 1, wherein the etchant used in the removal of the thin film sacrificial layer is hydrogen fluoride(HF).

3. The method of claim 1, wherein the thin film protection layer is removed by using a plasma etching method.

4. The method of claim 1, after the removal of the thin film protection layer, further involves the steps of:

removing remnants of the thin film protection layer by using a chemical;

rinsing away the chemical by using a second rinse; and

removing the second rinse.

5. The method of claim 4, wherein the first rinse and the second rinse are deionized water or methanol.

6. The method of claim 4, wherein the first rinse and the second rinse are removed by drying in a vacuum.

7. The method of claim 4, wherein the first rinse and the second rinse are removed by using a spin drying method.

8. The method of claim 4, wherein the chemical used in the removal of the remnants of the thin film protection layer is advanced chemical technology(ACT)-CMI.

9. The method of claim 1, wherein each of the thin film actuated mirrors has a bimorph structure.

10. The method of claim 1, further involves the formation of additional electrode and electrodisplacive layers, successively, after depositing the electrodisplacive layer.