CN-116075766-B - Air gap encapsulation of nanostructured optical devices

Abstract

Embodiments described herein relate to encapsulated optical devices and methods of forming optical devices with controllable air gap encapsulation. In one embodiment, a plurality of openings are formed in the support layer around the plurality of optical device structures to create a high index contrast between the optical device structures, the support layer, and the openings. In another embodiment, the sacrificial material is disposed between the optical device structures and then the encapsulation layer is disposed over the optical device structures. The sacrificial material is removed to form a space defined by the encapsulation layer, the substrate, and each of the optical device structures. In yet another embodiment, the encapsulation layer is disposed over the optical device structures, thereby forming a space defined by the encapsulation layer, the substrate, and each of the optical device structures.

Inventors

• Saijie tok Garrett dosha
• OHNO KOICHI
• Roger Meyer Timmerman dijason
• Luther Zhenyi Taio
• GUO JINRUI

Assignees

• 应用材料公司

Dates

Publication Date

20260512

Application Date

20210622

Priority Date

20200709

Claims (16)

1. 1. An optical device, comprising: A plurality of optical device structures disposed in or on a substrate, each structure of the plurality of optical device structures comprising: a critical dimension of less than 2 microns, the critical dimension corresponding to a width or diameter of a cross-section of each structure, and A structural material having an optical device refractive index between about 1.7 and about 4.0, and A support layer surrounding each of the plurality of optical device structures, the support layer providing mechanical support for the plurality of optical device structures, the support layer comprising: a support material having a support layer refractive index of about 1.0 to about 1.5, and A plurality of openings disposed through the support layer, each opening of the plurality of openings adjoining two or more optical device structures, the plurality of openings having a refractive index of about 1.0.
2. 2. The optical device of claim 1, wherein the plurality of optical device structures have a structure height and the support layer has a support layer height, the support layer height being greater than the structure height.
3. 3. The optical device of claim 1, wherein the plurality of optical device structures have a structure height and the support layer has a support layer height, the support layer height being equal to the structure height.
4. 4. The optical device of claim 1, wherein the optical device structure comprises one or more of titanium dioxide (TiO 2 ), zinc oxide (ZnO), tiN dioxide (SnO 2 ), niobium oxide (Nb 2 O 5 ), aluminum doped zinc oxide, titanium nitride (TiN), zirconium dioxide (ZrO 2 ), indium TiN oxide, tantalum pentoxide (Ta 2 O 5 ), fluorine doped TiN oxide, vanadium (IV) oxide, aluminum oxide (Al 2 O 3 ), cadmium stannate (Cd 2 SnO 4 ), zinc stannate (SnZnO 3 ), silicon nitride (Si 3 N 4 ), silicon oxycarbide (SiOC), silicon oxynitride (SiON), silicon dioxide (SiO 2 ).
5. 5. A method of forming an optical device, comprising the steps of: disposing a support layer on the substrate and between the plurality of optical device structures, the support layer being coplanar with a first hard mask layer disposed on the plurality of optical device structures; disposing a second hard mask layer over the support layer and the first hard mask layer; providing a resist layer over the second hard mask layer; Exposing a pattern in the resist layer, the pattern exposing exposed portions of the second hard mask layer, the pattern corresponding to openings to be formed in the support layer; etching the exposed portion of the second hard mask layer; etching the exposed portion of the support layer to form the opening through the support layer, and Removing the first hard mask layer and the second hard mask layer, Wherein the opening comprises air having a refractive index of about 1.0, the plurality of optic structures comprises a structural material having an optic refractive index of between about 1.7 and about 4.0, and the support layer comprises a support material having a support layer refractive index of about 1.0 to about 1.6.
6. 6. The method of claim 5, wherein the resist layer is a three-layer stack comprising an organic planarizing layer, an anti-reflective coating, and a photoresist layer.
7. 7. The method of claim 5, the step of disposing the support layer on the substrate and between the plurality of optical device structures further comprising the step of etching the support layer to be coplanar with the first hard mask layer.
8. 8. The method of claim 5, further comprising the step of etching the opening to expand the width or diameter of the opening.
9. 9. A method of forming an optical device, comprising the steps of: disposing a sacrificial material on the substrate and between the optical device structures of a plurality of optical device structures, the plurality of optical device structures comprising: a critical dimension of less than 2 microns, the critical dimension corresponding to a width or diameter of a cross-section of the optical device structure, and A structural material having an optical device refractive index between about 1.7 and about 4.0; providing an encapsulation layer over the plurality of optical device structures and the sacrificial material, the encapsulation layer comprising an encapsulation material having an encapsulation refractive index of about 1.0 to about 1.6, wherein the encapsulation layer may further include a plurality of openings provided through the encapsulation layer for removal of the sacrificial material, and Removing the sacrificial material using an etching process, wherein: the encapsulation layer, the substrate, and each of the plurality of optical device structures define a space therebetween, the space having a refractive index of about 1.0.
10. 10. The method of claim 9, further comprising the step of depositing material in the plurality of openings after the sacrificial material has been removed.
11. 11. The method of claim 9, the etching process further comprising the step of utilizing an etch chemistry that etches the sacrificial material at a higher rate than the encapsulation layer.
12. 12. An optical device, comprising: a plurality of optical device structures disposed in or on a substrate, the plurality of optical device structures comprising: a critical dimension of less than 2 microns, the critical dimension corresponding to a width or diameter of a cross-section of the optical device structure, and A structural material having an optical device refractive index between about 1.7 and about 4.0, and An encapsulation layer comprising: An encapsulation refractive index of about 1.0 to about 1.6; A first portion of a first material surrounding a top surface of the plurality of optical device structures, the first portion of the first material comprising: a gap defined between the first portions, and A second portion of a second material, the second portion disposed at least in the gap, wherein: The encapsulation layer, the substrate, and each of the plurality of optical device structures define a space therebetween, the space having a refractive index of about 1.0, and The first and second portions of the encapsulation layer are coplanar with one another.
13. 13. The optical device of claim 12, wherein a second plurality of optical device structures may be disposed on the encapsulation layer to create a multilayer optical device.
14. 14. The optical device of claim 12, wherein the optical device structure comprises one or more of titanium dioxide (TiO 2 ), zinc oxide (ZnO), tiN dioxide (SnO 2 ), niobium oxide (Nb 2 O 5 ), aluminum doped zinc oxide, titanium nitride (TiN), zirconium dioxide (ZrO 2 ), indium TiN oxide, tantalum pentoxide (Ta 2 O 5 ), fluorine doped TiN oxide, vanadium (IV) oxide, aluminum oxide (Al 2 O 3 ), cadmium stannate (Cd 2 SnO 4 ), zinc stannate (SnZnO 3 ), silicon nitride (Si 3 N 4 ), silicon oxycarbide (SiOC), silicon oxynitride (SiON), silicon dioxide (SiO 2 ).
15. 15. A method of forming an optical device, comprising the steps of: Providing a first portion of an encapsulation layer surrounding a top surface of a plurality of optical device structures, the plurality of optical devices being disposed in or on a substrate, the plurality of optical device structures comprising: a critical dimension of less than 2 microns, the critical dimension corresponding to a width or diameter of a cross-section of the optical device structure, and A structural material having an optical device refractive index between about 1.7 and about 4.0, the first portion of the encapsulation layer comprising: a first material having a first refractive index of about 1.0 to about 1.6, and A gap defined between the first portions of the encapsulation layer, and Providing a second portion of the encapsulation layer in at least the gap between the first portions of the encapsulation layer to fill the gap, the second portion comprising a second material having a second refractive index of about 1.0 to about 1.6, wherein: the first and second portions, the substrate, and the plurality of optical device structures define a space therebetween, the space having a refractive index of about 1.0, an The first and second portions of the encapsulation layer are planarized via a chemical mechanical polishing process or a reactive ion etch.
16. 16. The method of claim 15, wherein the optical device structure comprises one or more of titanium dioxide (TiO 2 ), zinc oxide (ZnO), tiN dioxide (SnO 2 ), niobium oxide (Nb 2 O 5 ), aluminum doped zinc oxide, titanium nitride (TiN), zirconium dioxide (ZrO 2 ), indium TiN oxide, tantalum pentoxide (Ta 2 O 5 ), fluorine doped TiN oxide, vanadium (IV) oxide, aluminum oxide (Al 2 O 3 ), cadmium stannate (Cd 2 SnO 4 ), zinc stannate (SnZnO 3 ), silicon nitride (Si 3 N 4 ), silicon oxycarbide (SiOC), silicon oxynitride (SiON), silicon dioxide (SiO 2 ).

Description

Air gap encapsulation of nanostructured optical devices Background Technical Field Embodiments of the present disclosure generally relate to optical devices. More particularly, embodiments described herein relate to encapsulated optical devices, and methods of forming optical devices having controllable air gap encapsulation. Background The nanostructured optical device comprises a structural arrangement with an in-plane dimension smaller than half the design wavelength of the light. For example, the structure may have sub-micron dimensions, e.g., nanometer-sized dimensions. An optical device comprising a waveguide combiner, such as an augmented reality waveguide, or a planar optical device, such as a super-structured surface (metasurface), may be composed of a single layer or multiple layers of such structures. Optical devices incorporating such structures require packaging for mechanical protection. The encapsulation material may also be used as a spacer between successive layers of a multilayer arrangement of optical structures. Furthermore, the optical properties of the encapsulant affect the optical device performance. For example, a high contrast between the refractive index of the material of the structures and the refractive index of the material between the structures is desirable to improve the performance of the optical device. Air having a refractive index of about 1.0 is a desirable material between the structures to improve the optical properties of the optical device. Thus, there is a need in the art for packaged optical devices and methods of forming optical devices with controllable air gap packages. Disclosure of Invention In one embodiment, an optical device is provided. The optical device includes a plurality of optical device structures disposed in or on a substrate. The optical device structures each have a critical dimension of less than 2 microns corresponding to a width or diameter of a cross section of the optical device structure and a structural material having an optical device refractive index between about 1.7 and about 4.0. The plurality of optic structures also includes a support layer surrounding each of the plurality of optic structures. The support layer includes a support material having a support layer refractive index of about 1.0 to 1.6. A plurality of openings are disposed through the support layer. Each opening of the plurality of openings abuts two or more structures of the plurality of structures. The plurality of openings have a refractive index of about 1.0. In another embodiment, a method is provided. The method includes disposing a support layer on the substrate and between the plurality of optical device structures. The support layer is coplanar with a first hard mask layer disposed over the plurality of optical device structures. The method further includes disposing a second hard mask layer over the support layer and the first hard mask layer and disposing a resist layer over the second hard mask layer. The method further includes exposing the pattern in the resist layer. The pattern exposes portions of the second hard mask layer, which pattern corresponds to openings to be formed in the support layer. The method further includes etching the exposed portion of the second hard mask layer. The method further includes etching the exposed portion of the support layer to form an opening through the support layer. The method further includes removing the first hard mask layer and the second hard mask layer. In another embodiment, a method is provided. The method includes disposing a sacrificial material on the substrate and between the optical device structures of the plurality of optical device structures. The plurality of optical device structures includes a critical dimension of less than 2 microns corresponding to a width or diameter of a cross-section of the optical device structures. The plurality of optic structures includes a structural material having an optic refractive index between about 1.7 and about 4.0. The method further includes disposing an encapsulation layer over the plurality of optical device structures and the sacrificial material. The encapsulation layer includes an encapsulation material having an encapsulation refractive index of about 1.0 to about 1.6. The method further includes removing the sacrificial material using an etching process. The etching process includes an etching chemistry that etches the sacrificial material at a higher rate than the encapsulation layer, wherein the encapsulation layer, the substrate, and each of the plurality of optical device structures define a space therebetween. The space has a refractive index of about 1.0. In another embodiment, an optical device is provided. The optical device includes a plurality of optical device structures disposed in or on a substrate. The plurality of optical device structures includes a critical dimension of less than 2 microns corresponding to a width or diameter of a cros