Method of fabricating interferometric devices using lift-off processing techniques

• US 7,906,353 B2
• Filed: 06/29/2009
• Issued: 03/15/2011
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Chui, Clarence, Tung, Ming-Hau
• Primary Examiner(s): Richards; N Drew
• Assistant Examiner(s): Withers; Grant S
• Application Number:
  US12/494,032
• Publication Number:
  US 20090262412A1
• Time in Patent Office: 624 Days
• Field of Search: 438/22
• US Class Current: 438/22
• 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

Abstract

Embodiments of the present disclosure include a method of fabricating interferometric devices using lift-off processing techniques. Use of lift-off processing in the fabrication of various layers of interferometric modulators, such as an optical stack or a flex layer, advantageously avoids individualized chemistries associated with the plurality of materials associated with each layer thereof. Moreover, use of lift-off processing allows much greater selection in both materials and facilities available for fabrication of interferometric modulators.

Claims

1. A method of making an interferometric modulator, comprising:

forming a lift-off stencil over a substrate;

depositing a first material layer over the lift-off stencil and over the substrate, wherein the first material layer comprises indium tin oxide;

depositing a second material layer over the first material layer, wherein the second material layer comprises molybdenum; and

removing the lift-off stencil to thereby form a patterned region comprising the second material layer over the first material layer.

2. The method of claim 1, in which the first material layer has a thickness that is greater than a thickness of the second material layer.

4. The method of claim 1, wherein the lift-off stencil comprises a polyimide release layer.

5. The method of claim 1, wherein the thickness of the lift-off stencil is in the range of about 1,500 Å

to about 50,000 Å

.

6. The method of claim 1, wherein the thickness of the first material layer is in the range of about 200 Å

to about 1,000 Å

.

7. The method of claim 1, wherein the thickness of the second material layer is in the range of about 30 Å

to about 150 Å

.

3. A method of making an interferometric modulator, comprising:

forming a lift-off stencil over a substrate;

depositing a first material layer over the lift-off stencil and over the substrate;

depositing a second material layer over the first material layer;

depositing a third material layer over the second material layer, wherein the third material layer comprises a dielectric material;

depositing a fourth material layer over the third material layer, wherein the fourth material layer comprises molybdenum; and

removing the lift-off stencil to thereby form a patterned region comprising the second material layer over the first material layer.

8. The method of claim 3, wherein the lift-off stencil comprises a polyimide release layer.

9. The method of claim 3, wherein the thickness of the lift-off stencil is in the range of about 1,500 Å

to about 50,000 Å

.

10. The method of claim 3, wherein the thickness of the first material layer is in the range of about 200 Å

to about 1,000 Å

.

11. The method of claim 3, wherein the thickness of the second material layer is in the range of about 30 Å

to about 150 Å

.

12. The method of claim 3, wherein the thickness of the third material layer is in the range of about 100 Å

to about 2,500 Å

.

13. The method of claim 3, wherein the thickness of the fourth material layer is in the range of about 400 Å

to about 6,000 Å

.

14. A method of making an interferometric modulator, comprising:

forming a lift-off stencil over a substrate;

depositing a first material layer over the lift-off stencil and over the substrate, wherein the first material layer comprises indium tin oxide;

depositing a second material layer over the first material layer, wherein the second material layer comprises chromium; and

removing the lift-off stencil to thereby form a patterned region comprising the second material layer over the first material layer.

15. The method of claim 14, wherein the lift-off stencil comprises a polyimide release layer.

16. The method of claim 14, wherein the thickness of the lift-off stencil is in the range of about 1,500 Å

to about 50,000 Å

.

17. The method of claim 14, wherein the thickness of the first material layer is in the range of about 200 Å

to about 1,000 Å

.

18. The method of claim 14, wherein the thickness of the second material layer is in the range of about 30 Å

to about 150 Å

.