Method of fabricating interferometric devices using lift-off processing techniques
View Patent ↗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.
1. A method of fabricating an interferometric modulator, comprising:
forming an optical stack on a transparent substrate using at least a first patterning fabrication process;
forming a supporting structure over the substrate; and
forming an upper mirror layer over the optical stack and supporting structure using at least a second patterning fabrication process;
wherein a cavity is formed by at least one surface of the optical stack, the supporting structure and the upper mirror layer, where movement of a portion of the upper mirror layer into the cavity changes the optical properties perceived from a surface of the substrate in a controllable and predictable manner, and wherein at least one of the first and second fabrication processes comprises a lift-off process;
wherein forming the upper mirror layer over the optical stack comprises depositing a sacrificial layer between the optical stack and the upper mirror layer; and
wherein the lift-off process comprises lifting off at least a portion of the optical stack along with at least a portion of the sacrificial layer.
2. The method of claim 1 , wherein the optical stack comprises at least one of a conductor layer, a lower mirror metal layer, and a dielectric layer.
3. The method of claim 2 , wherein the optical stack comprises a lower mirror metal layer.
4. The method of claim 3 , wherein at least the lower mirror metal layer forms a row electrode.
5. The method of claim 1 , further comprising removing at least a portion of the sacrificial layer to form the cavity.
6. The method of claim 1 , wherein the upper mirror layer comprises a flexible metal conductor layer.
7. The method of claim 6 , wherein at least the upper mirror layer forms a column electrode.
8. The method of claim 1 , wherein the first and second fabrication processes comprise lift-off processes.
9. The method of claim 1 , further comprising forming an imaging application.
10. The method of claim 9 , wherein the imaging application comprises a flat panel display.
11. The method of claim 10 , wherein the flat panel display is part of a mobile electronic device.
12. The method of claim 9 , wherein the imaging application comprises at least one of a handheld computer, a personal digital assistant, a laptop computer, a mobile telephone, a handheld video gaming device, a home appliance, a television, a timepiece, a kiosk, and a automobile computing device.
13. The method of claim 1 in which the lift-off process comprises forming a generally T-shaped lift-off stencil.
14. The method of claim 1 in which the lift-off process comprises patterning a lift-off stencil.
15. The method of claim 14 in which the patterning of the lift-off stencil comprises depositing a photoresist over a polymer.
16. The method of claim 1 in which the lift-off process comprises wet etching to remove a lift-off stencil.
17. The method of claim 1 further comprising depositing a deformable layer over the upper mirror layer.
18. The method of claim 17 in which the upper mirror layer is suspended from the deformable layer after removal of the sacrificial layer.