Photoresist loading scheme for flat panel optics fabrication

Abstract

Embodiments of the present disclosure relate to methods of fabricating optical devices. One embodiment of the method includes disposing a layer of structural material on a surface of a substrate and disposing a patterned photoresist over the layer of structural material. The patterned photoresist has at least one device portion and at least one auxiliary portion. Each device portion and each auxiliary portion exposes an unmasked portion of the layer of structural material. The unmasked portions of the layer of structural material corresponding to each device portion and each auxiliary portion are etched. Etching the unmasked portions forms at least one optical device having a device structure corresponding to the unmasked portion of the at least one device portion and at least one auxiliary region having an auxiliary structure corresponding to the unmasked portion of the at least one auxiliary portion.

Description

[0001] BACKGROUND

[0002] TECHNICAL FIELD

[0003] Embodiments of the present disclosure generally relate to optical devices. More specifically, the embodiments described herein provide for the fabrication of one or more optical devices.

[0004] Description of the Related Art

[0005] Optical devices can be used to manipulate the propagation of light. One example of an optical device is a flat optical device. Flat optical devices in the visible and near infrared spectrum can require a transparent substrate with structures, such as nanostructures, disposed on the substrate. However, as an emerging technology, processing a transparent substrate to form an optical device is both complex and challenging. For example, large areas of structure material in the regions between adjacent optical devices and between the optical devices and the perimeter of the substrate can be etched away, such that the optical devices are only surrounded by the surface of the substrate. Surrounding the optical devices only by the surface of the substrate creates an inability to determine the endpoint of the etching process, which can result in undesirable critical dimensions of the structures.

[0006] Accordingly, there is a need in the art for improved methods of fabricating optical devices.

[0007] SUMMARY

[0008] In one embodiment, a method is provided. The method includes disposing a layer of structure material on a surface of a substrate and disposing a patterned photoresist over the layer of structure material. The patterned photoresist has at least one device portion and at least one auxiliary portion. Each device portion and each auxiliary portion exposes an unmasked portion of the layer of structure material. The unmasked portions of the layer of structure material corresponding to each device portion and each auxiliary portion are etched. Etching the unmasked portions forms at least one optical device having a device structure corresponding to the unmasked portion of the at least one device portion and at least one auxiliary region having an auxiliary structure corresponding to the unmasked portion of the at least one auxiliary portion.

[0009] In another embodiment, a method is provided. The method includes disposing a layer of structural material on a surface of a substrate and disposing a patterned photoresist over the layer of structural material. The patterned photoresist has at least one device portion, at least one auxiliary portion, and at least one intermediate portion, the at least one device portion exposing unmasked device portions of the layer of structural material, the at least one auxiliary portion masking at least one auxiliary region of the substrate, the auxiliary region being defined by intermediate regions to be formed and a periphery of the substrate, and the at least one intermediate portion exposing unmasked intermediate portions of the layer of structural material between the device portions and the auxiliary portions. The unmasked device portions and the unmasked intermediate portions of the layer of structural material corresponding to the device portions and the intermediate portions are etched. Etching the unmasked device portions and the unmasked intermediate portions forms at least one optical device having a device structure corresponding to the unmasked portions of the at least one device portion and at least one intermediate region between the optical device and the auxiliary region and exposing the surface of the substrate. The auxiliary region is masked by the auxiliary portions.

[0010] In another embodiment, a method is provided. The method includes disposing a layer of structural material on a surface of a substrate and disposing a patterned photoresist over the layer of structural material. The patterned photoresist has at least one device portion, at least one auxiliary portion, and at least one intermediate portion, the at least one device portion exposing unmasked device portions of the layer of structural material, the at least one auxiliary portion masking at least one auxiliary region of the substrate, the auxiliary region being defined by intermediate regions to be formed and a periphery of the substrate, and the at least one intermediate portion exposing unmasked intermediate portions of the layer of structural material between the device portions and the auxiliary portions. The unmasked device portions and the unmasked intermediate portions of the layer of structural material corresponding to the device portions and the intermediate portions are etched. Etching the unmasked device portions and the unmasked intermediate portions forms at least one optical device having a device structure corresponding to the unmasked portions of the at least one device portion and at least one intermediate region between the optical device and the auxiliary region and exposing the surface of the substrate. The auxiliary region is masked by the auxiliary portions.

[0011] BRIEF DESCRIPTION OF DRAWINGS

[0012] A more particular description of the disclosure briefly described in the foregoing summary will be rendered by reference to the implementations, some of which are illustrated in the drawings, which are shown by way of example only and thus are not intended to limit the scope of the disclosure. In addition, it is to be understood that other implementations can be utilized, as structural and operational changes can be made without departing from the scope of the present disclosure.

[0013] FIG. 1is a flowchart illustrating operations of a method for manufacturing one or more optical devices according to an embodiment.

[0014] FIGS. 2A-2C is a schematic top view of a substrate during a method for manufacturing an optical device according to an embodiment.

[0015] FIGS. 2D-2F is a schematic cross-sectional view of a substrate during a method for manufacturing an optical device according to an embodiment.

[0016] FIGS. 3A-3C is a schematic top view of a substrate during a method for manufacturing an optical device according to an embodiment.

[0017] FIGS. 3D-3F is a schematic cross-sectional view of a substrate during a method for manufacturing an optical device according to an embodiment.

[0018] FIG. 4 is a flowchart illustrating operations of a method for manufacturing one or more optical devices according to an embodiment.

[0019] FIGS. 5A-5C is a schematic top view of a substrate during a method for manufacturing an optical device according to an embodiment.

[0020] FIGS. 5D-5F is a schematic cross-sectional view of a substrate during a method for manufacturing an optical device according to an embodiment.

[0021] FIGS. 6A-6C is a schematic top view of a substrate during a method for manufacturing an optical device according to an embodiment.

[0022] FIGS. 6D-6F is a schematic cross-sectional view of a substrate during a method for manufacturing an optical device according to an embodiment.

[0023] DETAILED DESCRIPTION

[0024] Embodiments of the present disclosure relate to a method for manufacturing an optical device. One embodiment of the method includes disposing a layer of structural material on a surface of a substrate and disposing a patterned photoresist over the layer of structural material. The patterned photoresist has at least one device portion and at least one auxiliary portion. Each device portion and each auxiliary portion exposes an unmasked portion of the layer of structural material. The unmasked portions of the layer of structural material corresponding to each device portion and each auxiliary portion are etched. Etching the unmasked portions forms at least one optical device having a device structure and at least one auxiliary region, the device structure corresponding to the unmasked portion of the at least one device portion, the at least one auxiliary region having an auxiliary structure corresponding to the unmasked portion of the at least one auxiliary portion.

[0025] FIG. 1 is a flowchart illustrating operations of a method 100 for fabricating one or more optical devices 200, 300. FIGS. 2A-2C is a schematic top view of a substrate 201 during the method 100 for fabricating an optical device 200 according to one embodiment, while FIGS. 2D-2F is a schematic cross-sectional view of a substrate 201 during the method 100 for fabricating an optical device 200 according to this embodiment, which can be combined with other embodiments described herein. FIGS. 3A-3C is a schematic top view of a substrate 201 during the method 100 for fabricating an optical device 300 according to another embodiment, while FIGS. 3D-3F is a schematic cross-sectional view of a substrate 201 during the method 100 for fabricating an optical device 300 according to this embodiment, which can be combined with other embodiments described herein.

[0026] At operation 101, as FIG. 2A with FIG. 2D and FIG. 3A with FIG. 3D illustrated in FIGS. 1A-1C, a photoresist material is disposed over the layer of structural material 202. The layer of structural material 202 is disposed over a surface 203 of the substrate 201. The photoresist material is developed to form a patterned photoresist 206, 306. The photoresist material can be disposed over the layer of structural material 202 using a spin-coating process. The patterned photoresist 206, 306 can include, but is not limited to, a photosensitive polymer-containing material. Developing the photoresist material can include performing a lithography process, such as photolithography and digital lithography.

[0027] The substrate 201 can also be selected to transmit an appropriate amount of light of a desired wavelength or range of wavelengths, such as one or more wavelengths from about 100 nanometers to about 3000 nanometers. Without being limited, in some embodiments, the substrate 201 is configured so that the substrate 201 transmits greater than or equal to about 50%, 60%, 70%, 80%, 90%, 95%, 99% of the IR to UV region of the optical spectrum. The substrate 201 can be formed of any suitable material, so long as the substrate 201 can sufficiently transmit light in the desired wavelength or range of wavelengths and can serve as a sufficient support for the optical device. In some embodiments, which can be combined with other embodiments described herein, the material of the substrate 201 has a relatively low refractive index compared to the refractive index of the material of the structure material layer 202. Substrate selection can include substrates of any suitable material, including but not limited to, amorphous dielectrics, non-amorphous dielectrics, crystalline dielectrics, silicon oxides, polymers, and combinations of the foregoing. In some embodiments, which can be combined with other embodiments described herein, the substrate 201 includes a transparent material. In one embodiment, which can be combined with other embodiments described herein, the substrate 201 is transparent and has an absorption coefficient less than 0.001. Suitable examples can include oxides, sulfides, phosphides, tellurides, or combinations of the foregoing. In one example, the substrate 201 includes a silicon (Si) containing material, a silicon dioxide (Si02) containing material, a sapphire containing material, and a high refractive index transparent material containing material.

[0028] The structural material layer 202 can be disposed over the surface 203 of the substrate 201 by using a liquid material casting process, a spin-coating process, a liquid spray-coating process, a dry powder coating process, a screen printing process, a doctor blading process, a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process, a plasma enhanced (PECVD) process, a flowable CVD (FCVD) process, an atomic layer deposition (ALD) process, an evaporation process, or a sputtering process. In one embodiment, which can be combined with other embodiments described herein, the structural material layer 202 includes a metal-containing dielectric material, not limited to a titanium dioxide (Ti02)-containing material, a zinc oxide (ZnO)-containing material, a tin dioxide (Sn02)-containing material, an aluminum-doped zinc oxide (AZO)-containing material, a fluorine-doped tin oxide (FTO)-containing material, a cadmium stannate (tin oxide) (CTO)-containing material, a niobium oxide (Nb205)-containing material, and a zinc stannate (tin oxide) (SnZn03)-containing material. In another embodiment, which can be combined with other embodiments described herein, the structural material includes a non-conductive amorphous material, such as a dielectric material. The dielectric material can include an amorphous dielectric, a non-amorphous dielectric, and a crystalline dielectric. Examples of the dielectric material include, but are not limited to, a Si-containing material, such as silicon nitride (Si3N4) and amorphous silicon (a-Si).

[0029] In one embodiment, which can be combined with other embodiments described herein, at operation 101, a patterned photoresist 206, 306 is disposed over one or more etch layers 204, such as a hardmask or etch stop layer, disposed over the structural material layer 202. The hardmask can be disposed over the structural material layer 202 by using a liquid material casting process, a spin-coating process, a liquid spray-coating process, a dry powder coating process, a screen printing process, a doctor blading process, a PVD process, a CVD process, a PECVD process, a FCVD process, an ALD process, an evaporation process, or a sputtering process. In one embodiment, the hardmask is an opaque hardmask that is removed after one or more optical devices 200 are formed. In another embodiment, the hardmask is a transparent hardmask. Examples of the hardmask include, but are not limited to, a chromium (Cr)-containing material, a silver (Ag)-containing material, a Si3N4-containing material, a Si02-containing material, a TiN-containing material, and a carbon (C)-containing material.

[0030] In one embodiment, which can be combined with other embodiments described herein, the patterned photoresist 206, 306 includes at least one device portion 208, 308 and at least one auxiliary portion 212, 312. In another embodiment, which can be combined with other embodiments described herein, the patterned photoresist 206, 306 includes at least one device portion 208, 308, at least one intermediate portion 210, 310, and at least one auxiliary portion 212, 312. Each intermediate portion 210, 310 is between the device portion 208, 308 and the auxiliary portion 212, 312. Each of the at least one device portion 208, 308, the at least one intermediate portion 210, 310, and the at least one auxiliary portion 212, 312 exposes an unmasked portion 205, 305 of the layer of structural material 202. As FIG. 2C With FIG. 2F FIGS. and FIG. 3C With FIG. 3F As shown in FIGS. 2 and 3, each device portion 208, 308 corresponds to one of the optical devices 200, 300 having an array of device structures 207 formed on or integrated with a surface 203 of a substrate 201. Each intermediate portion 210, 310 corresponds to an intermediate region 214, 314 between the optical device 200, 300 and the auxiliary region 216, 316. Each auxiliary portion 212, 312 corresponds to an auxiliary region 216, 316 of the substrate 201 having an array of auxiliary structures 209, 309, also referred to as dummy structures described in detail herein, formed on or integrated with the surface 203 of the substrate 201. The auxiliary region 216, 316 is defined by each intermediate region 214, 314 and a perimeter of the substrate 201.

[0031] At operation 102, as FIG. 2B With FIG. 2E and FIG. 3B With FIG. 3EAs shown, the unmasked portions 205 and 305 of the structural material layer 202 are etched. Etching the unmasked portions 205 and 305 of the structural material layer 202 includes at least one dry etching process, not limited to ion implantation, ion etching, reactive ion etching (RIE), directional RIE, plasma etching, and at least one of wet etching. Etching the unmasked portions 205 and 305 forms the device structure 207 of the optical devices 200 and 300, the surface 203 of the substrate 201 exposed in the intermediate regions 214 and 314, and the auxiliary structures 209 and 309 of the auxiliary regions 216 and 316. In one embodiment that can be combined with other embodiments described herein, one or more unmasked portions 211 of the etched layers 204 are etched prior to the unmasked portions 205 and 305 of the structural material layer 202. In one embodiment that can be combined with other embodiments described herein, at least one of the etched layers 204 has a greater etch selectivity than the structural material layer 202. In operation 103, as... FIG. 2C and FIG. 2F and FIG. 3C and FIG. 3F As shown, patterned photoresist 206, 306 is removed. Removal of patterned photoresist 206, 306 may include the lithographic printing process or etching process described herein. In embodiments having one or more etched layers 204, one or more etched layers 204 are removed. Removal of one or more etched layers 204 may include ion etching, RIE, or selective wet chemical etching.

[0032] In one embodiment, which can be combined with other embodiments described herein, the device structures 207 can have the same dimensions, such as one of height and width. In another embodiment, which can be combined with other embodiments described herein, at least one of the device structures 207 can have at least one dimension, such as one of height and width, that is different from the dimensions of another structure of the device structures 207. In some embodiments described herein, the width of each of the device structures 207 is the critical dimension 213. In some embodiments described herein, the width of each of the auxiliary structures 209, 309 is the critical dimension 221, 321. In one embodiment, which can be combined with other embodiments described herein, the device structures 207 can have the same refractive index. In another embodiment, which can be combined with other embodiments described herein, at least one of the device structures 207 can have a refractive index that is different from the refractive index of another structure of the device structures 207. In some embodiments, which can be combined with other embodiments described herein, the optical device 200, 300 is a metasurface having device structures 207 that are nanostructures in the form of nanoscale features. In one example, the nanostructures have a critical dimension 213, 313 that is less than about 1000 nm, for example, less than about 500 nm, less than about 200 nm, less than about 100 nm, or even less than about 20 nm.

[0033] The device structures 207 have a device gap 218 defined as the distance between adjacent device structures 207. In one embodiment, which can be combined with other embodiments described herein, the device gap 218 of each of the device structures 207 can be substantially the same. In another embodiment, which can be combined with other embodiments described herein, at least one of the device structures 207 can have at least one different device gap 218. The auxiliary structures 209, 309 have an auxiliary gap 219, 319 defined as the distance between adjacent auxiliary structures 209, 309. In one embodiment, which can be combined with other embodiments described herein, the auxiliary gap 219, 319 of each of the auxiliary structures 209, 309 can be substantially the same. In another embodiment, which can be combined with other embodiments described herein, at least one of the auxiliary structures 209, 309 can have at least one different auxiliary gap 219, 319.

[0034] The method 100 forms one or more optical devices 200 over the substrate 201, the one or more optical devices 200 separated from the auxiliary region 216 by the intermediate region 214. The optical devices 200 have a relationship between the critical dimension 213 of the device structure 207 and the critical dimension 221 of the auxiliary structure 209. For portions of the optical devices 200 and the auxiliary region 216 having substantially the same device gap 218 and auxiliary gap 219, the critical dimension 213 of the device structure 207 and the critical dimension 221 of the auxiliary structure 209 are substantially the same. The substantially equal critical dimension 213 and critical dimension 221 of the portions having substantially equal device gap 218 and auxiliary gap 219 provide control of load dependence during etching of the unmasked portions 205 of the structure material layer 202. Load dependence means the relationship between the load of the patterned photoresist 206, 306 (i.e., the exposed areas of the unmasked portions 205) and the etch rate of the structure material layer 202.

[0035] Because the critical dimension 213 of the device structure 207 and the critical dimension 221 of the auxiliary structure 209 are substantially equal, the width 223 of the unmasked portions 205 is substantially the same for both the device portions 208 and the auxiliary portions 212, the device portions 208 and the auxiliary portions 212 corresponding to the portions of the optical devices 200 and the auxiliary region 216 having substantially the same device gap 218 and auxiliary gap 219. The device portions 208 and the auxiliary portions 212 having substantially equal width 223 of the unmasked portions 205 provide a fixed load of the patterned photoresist 206. This fixed load provides end point detection during etching of the operation 102 and provides a critical dimension 213 of the device structure 207 of less than about 1000 nm, for example, less than about 500 nm, less than about 200 nm, less than about 100 nm, or even less than about 20 nm. The end point detection provides the ability to terminate etching of the operation 102 once the device structure 207 is formed, such that the critical dimension 213 and the sidewall profile of the device structure 207 are maintained. For the fixed load of the patterned photoresist 206, 306, the critical dimension 213 is substantially the same for both the device structure 207 and the auxiliary structure 209. The critical dimension 213 is controlled such that the auxiliary structure 209 reduces or impedes the optical interaction of the beam with the substrate and the optical devices 200.

[0036] The method 100 forms one or more optical devices 300 over the substrate 201, the one or more optical devices 300 separated from the auxiliary region 316 by the intermediate region 314. The optical devices 300 have a relationship between the critical dimension 213 of the device structure 207 and the critical dimension 321 of the auxiliary structure 309. For portions of the optical devices 300 and the auxiliary region 316 having substantially the same device gap 218 and auxiliary gap 319, the critical dimension 213 of the device structure 207 is less than the critical dimension 321 of the auxiliary structure 309. The critical dimension 213 of the device structure 207 that is less than the critical dimension 321 of the auxiliary structure 309 provides a substantially fixed loading of the patterned photoresist 306. The substantially fixed loading provides an end point detection during the etch of operation 102 and provides a critical dimension 213 of the device structure 207 that is less than about 1000 nm, for example, less than about 500 nm, less than about 200 nm, less than about 100 nm, or even less than about 20 nm. For the substantially fixed loading of the patterned photoresist 306, the critical dimension 213 of the device structure 207 is less than the critical dimension 315 of the auxiliary structure 309 while the sidewall profile of the device structure 207 is maintained. The critical dimension 315 is controlled such that the auxiliary structure 309 reduces or impedes the optical interaction of the beam with the substrate and the optical device 300.

[0037] FIG. 4 is a flowchart illustrating operations of a method 400 for fabricating one or more optical devices 500, 600. According to one embodiment, which can be combined with other embodiments described herein, FIGS. 5A-5C is a schematic top view of the substrate 201 during the method 400 for fabricating the optical device 500, while FIGS. 5D-5F is a schematic cross-sectional view of the substrate 201 during the method 400 for fabricating the optical device 500. According to another embodiment, which can be combined with other embodiments described herein, FIGS. 6A-6C is a schematic top view of the substrate 201 during the method 400 for fabricating the optical device 600, while FIGS. 6D-6F is a schematic cross-sectional view of the substrate 201 during the method 400 for fabricating the optical device 600.

[0038] At operation 401, as FIG. 5A with FIG. 5D and FIG. 6A with FIG. 6DA photoresist material is disposed over the structure material layer 202, as shown. The structure material layer 202 is disposed over a surface 203 of the substrate 201. The photoresist material is developed to form a patterned photoresist 506, 606. The photoresist material can be disposed over the structure material layer 202 using a spin-on coating process. The photoresist material can include, but is not limited to, a photosensitive polymer-containing material. In one embodiment, which can be combined with other embodiments described herein, at operation 401, the patterned photoresist 506, 606 is disposed over one or more etch layers 204, such as a hardmask or etch stop layer, disposed over the structure material layer 202. Developing the photoresist material can include performing a lithography process, such as photolithography and digital lithography.

[0039] In one embodiment, which can be combined with other embodiments described herein, the patterned photoresist 506, 606 includes at least one device portion 508, 608 and at least one auxiliary portion 512, 612. In another embodiment, which can be combined with other embodiments described herein, the patterned photoresist 506, 606 includes at least one device portion 508, 608, at least one intermediate portion 510, 610, and at least one auxiliary portion 512, 612. Each intermediate portion 510, 610 is between the device portion 508, 608 and the auxiliary portion 512, 612. The at least one device portion 508, 608 exposes an unmasked device portion 505 of the structure material layer 202. The auxiliary portion 512, 612 masks (i.e., covers) the structure material layer 202. The at least one intermediate portion 510, 610 exposes an unmasked intermediate portion 511, 611 of the structure material layer 202 between the device portion 508, 608 and the auxiliary portion 512, 612. Each of the unmasked intermediate portions 511, 611 has an unmasked distance 517, 617 from the device portion 508, 608 to the auxiliary portion 512, 612. In one embodiment, which can be combined with other embodiments described herein, the unmasked distance 517 between each device portion 508 and each auxiliary portion 512 is fixed. In another embodiment, which can be combined with other embodiments described herein, the unmasked distance 617 between each device portion 608 and each auxiliary portion 612 is varied.

[0040] At operation 402, as FIG. 5B With FIG. 5E And FIG. 6B With FIG. 6EAs shown in FIG. 5A, the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 are etched. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 includes at least one dry etching process, not limited to at least one of the following: ion implantation, ion etching, reactive ion etching (RIE), directional RIE, plasma etching, and wet etching. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 forms the device structures 207 of the optical devices 500, 600, and exposes the surface 203 of the substrate 201 in the intermediate regions 514, 614. The auxiliary portions 512, 612 of the patterned photoresist 506, 606 remain over the structural material layer 202.

[0041] As shown in FIG. 6A, the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 are etched. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 includes at least one dry etching process, not limited to at least one of the following: ion implantation, ion etching, reactive ion etching (RIE), directional RIE, plasma etching, and wet etching. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 forms the device structures 207 of the optical devices 500, 600, and exposes the surface 203 of the substrate 201 in the intermediate regions 514, 614. The auxiliary portions 512, 612 of the patterned photoresist 506, 606 remain over the structural material layer 202. FIG. 5C FIG. 5D As shown in FIG. 5A, the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 are etched. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 includes at least one dry etching process, not limited to at least one of the following: ion implantation, ion etching, reactive ion etching (RIE), directional RIE, plasma etching, and wet etching. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 forms the device structures 207 of the optical devices 500, 600, and exposes the surface 203 of the substrate 201 in the intermediate regions 514, 614. The auxiliary portions 512, 612 of the patterned photoresist 506, 606 remain over the structural material layer 202. FIG. 6C FIG. 6F As shown in FIG. 6A, the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 are etched. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 includes at least one dry etching process, not limited to at least one of the following: ion implantation, ion etching, reactive ion etching (RIE), directional RIE, plasma etching, and wet etching. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 forms the device structures 207 of the optical devices 500, 600, and exposes the surface 203 of the substrate 201 in the intermediate regions 514, 614. The auxiliary portions 512, 612 of the patterned photoresist 506, 606 remain over the structural material layer 202.

[0042] As shown in FIG. 5A, the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 are etched. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 includes at least one dry etching process, not limited to at least one of the following: ion implantation, ion etching, reactive ion etching (RIE), directional RIE, plasma etching, and wet etching. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 forms the device structures 207 of the optical devices 500, 600, and exposes the surface 203 of the substrate 201 in the intermediate regions 514, 614. The auxiliary portions 512, 612 of the patterned photoresist 506, 606 remain over the structural material layer 202. FIG. 5C FIG. 5D As shown in FIG. 6A, the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 are etched. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 includes at least one dry etching process, not limited to at least one of the following: ion implantation, ion etching, reactive ion etching (RIE), directional RIE, plasma etching, and wet etching. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 forms the device structures 207 of the optical devices 500, 600, and exposes the surface 203 of the substrate 201 in the intermediate regions 514, 614. The auxiliary portions 512, 612 of the patterned photoresist 506, 606 remain over the structural material layer 202. FIG. 6C FIG. 6F As shown in FIG. 5A, the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 are etched. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 of the structural material layer 202 includes at least one dry etching process, not limited to at least one of the following: ion implantation, ion etching, reactive ion etching (RIE), directional RIE, plasma etching, and wet etching. Etching the unmasked device portions 505 and the unmasked intermediate portions 511, 611 forms the device structures 207 of the optical devices 500, 600, and exposes the surface 203 of the substrate 201 in the intermediate regions 514, 614. The auxiliary portions 512, 612 of the patterned photoresist 506, 606 remain over the structural material layer 202.

[0043] ​​​​The unmasked distance 517 between each device portion 508 and each auxiliary portion 512 is fixed, which provides a loading of the patterned photoresist 506. This loading provides end point detection during the etching of operation 402 and provides a critical dimension 213 of the device structure 207 of less than about 1000 nm, for example, less than about 500 nm, less than about 200 nm, less than about 100 nm, or even less than about 20 nm. The unmasked distance 517 between each device portion 508 and each auxiliary portion 512 corresponds to an exposed distance 521 of the surface 203 between each intermediate region 514 and each auxiliary portion 512, which is fixed. The fixed exposed distance 521 provides control over the optical interaction of the auxiliary portions 512 with light incident on the optical device 500. The unmasked distance 617 between each device portion 608 and each auxiliary portion 612 is varied, which provides a loading of the patterned photoresist 606. This loading provides end point detection during the etching of operation 402 and provides a critical dimension 213 of the device structure 207 of less than about 1000 nm, for example, less than about 500 nm, less than about 200 nm, less than about 100 nm, or even less than about 20 nm. The unmasked distance 617 between each device portion 608 and each auxiliary portion 612 corresponds to an exposed distance 621 of the surface 203 between each intermediate region 614 and each auxiliary portion 612, which is varied. The varied exposed distance 621 provides control over the optical interaction of the auxiliary portions 612 with light incident on the optical device 600. The dark field masking of the auxiliary portions 512, 612 over the auxiliary portions 512, 612 acts as apertures that avoid beam degradation of the functionality and efficiency of the optical device 500, 600 by avoiding beam optical interaction with the substrate outside of the optical device 500, 600.

[0044] While the foregoing is related to implementations of the present disclosure, other and further implementations of the present disclosure can be devised without departing from the basic scope thereof, and the scope of the present disclosure is determined by the appended claims.

Claims

1. An apparatus comprising: at least one optical device having one or more arrays of nanostructures disposed on or integrated with a surface of a substrate, each of the nanostructures having: an apparatus critical dimension defined by a width of the nanostructure, the apparatus critical dimension being less than 1000 nanometers (nm); and device gap, defined as the distance between adjacent nanostructures; and an auxiliary region defined by an intermediate region, the auxiliary region disposed around a perimeter of each optical device, the surface of the substrate exposed in the intermediate region, the auxiliary region having one or more arrays of auxiliary structures disposed on or integrated with the surface of the substrate, each of the auxiliary structures having: an auxiliary critical dimension defined by the width of the auxiliary structure; and an auxiliary gap defined as a distance between adjacent auxiliary structures, wherein: the apparatus critical dimension is less than the auxiliary critical dimension; or the apparatus critical dimension is equal to the auxiliary critical dimension.

2. The apparatus of claim 1, wherein at least one of the nanostructures or the auxiliary structures comprises one or more of: a titanium dioxide (Ti02)-containing material, a zinc oxide (ZnO)-containing material, a tin dioxide (Sn02)-containing material, a cadmium stannate-containing material, a zinc stannate-containing material, a niobium oxide-containing material, or a silicon-containing material.

3. The apparatus of claim 1, wherein at least one of the nanostructures or the auxiliary structures comprises one or more of: a titanium dioxide (Ti02)-containing material, a zinc oxide (ZnO)-containing material, a fluorine-doped tin oxide-containing material, a cadmium stannate-containing material, a zinc stannate-containing material, a niobium oxide-containing material, or a silicon-containing material.

4. The apparatus of claim 2 or claim 3, wherein the zinc oxide (ZnO)-containing material is an aluminum-doped zinc oxide-containing material.

5. The apparatus of claim 2 or claim 3, wherein the silicon-containing material is a silicon nitride (Si3N4)-containing material.

6. The apparatus of claim 2 or claim 3, wherein the zinc stannate is SnZn03.

7. The apparatus of claim 2 or claim 3, wherein the niobium oxide is Nb205.

8. The apparatus of claim 1, wherein the nanostructures and the auxiliary structures are composed of the same material.

9. An apparatus comprising: at least one optical device having one or more arrays of nanostructures disposed on or integrated with a surface of a substrate, each of the nanostructures having: an apparatus critical dimension defined by a width of the nanostructure, the apparatus critical dimension being less than 1000 nanometers (nm); and an apparatus gap defined as a distance between adjacent nanostructures; and an auxiliary region defined by an intermediate region, the auxiliary region disposed around a perimeter of each optical device, the surface of the substrate exposed in the intermediate region, the auxiliary region having one or more arrays of auxiliary structures disposed on or integrated with the surface of the substrate, each of the auxiliary structures having: an auxiliary critical dimension defined by the width of the auxiliary structure; and an auxiliary gap defined as a distance between adjacent auxiliary structures, wherein: the apparatus critical dimension is less than the auxiliary critical dimension; or the apparatus critical dimension is equal to the auxiliary critical dimension. an intermediate region surrounding each optical device, the intermediate region exposing the surface of the substrate corresponding to an exposed distance between an auxiliary region of the substrate and each optical device, the auxiliary region having a dark field mask, the auxiliary region disposed on or integral with the surface of the substrate, the auxiliary region having one or more arrays of auxiliary structures disposed on or integral with the surface of the substrate, each of the auxiliary structures having an auxiliary critical dimension defined by the width of the auxiliary structure, wherein: the device critical dimension is less than the auxiliary critical dimension; or the device critical dimension is equal to the auxiliary critical dimension.

10. The apparatus of claim 9, wherein the dark field mask is at least one of a photoresist or a hardmask disposed over an auxiliary structure disposed on the surface of the substrate.

11. The apparatus of claim 10, wherein the hardmask comprises at least one of a chromium (Cr)-containing material, a silver (Ag)-containing material, a silicon nitride (Si3N4)-containing material, a silicon dioxide (SiO2)-containing material, a titanium nitride (TiN)-containing material, or a carbon (C)-containing material.

12. The apparatus of claim 10, wherein the nanostructure and the auxiliary structure are composed of the same material.

13. The apparatus of claim 9, wherein the exposed distance between the auxiliary region of the substrate and each optical device is fixed.

14. The apparatus of claim 9, wherein the exposed distance between the auxiliary region of the substrate and each optical device is varied.

15. The apparatus of claim 9, wherein the nanostructure comprises one or more of a titanium dioxide (TiO2)-containing material, a zinc oxide (ZnO)-containing material, a tin dioxide (SnO2)-containing material, a cadmium stannate-containing material, a zinc stannate-containing material, a niobium oxide-containing material, or a silicon-containing material.

16. The apparatus of claim 9, wherein the nanostructure comprises one or more of a titanium dioxide (TiO2)-containing material, a zinc oxide (ZnO)-containing material, a fluorine-doped tin oxide-containing material, a cadmium stannate-containing material, a zinc stannate-containing material, a niobium oxide-containing material, or a silicon-containing material.

17. The apparatus of claim 15 or claim 16, wherein the zinc oxide (ZnO)-containing material is an aluminum-doped zinc oxide-containing material.

18. The apparatus of claim 15 or claim 16, wherein the silicon-containing material is a silicon nitride (Si3N4)-containing material.

19. The apparatus of claim 15 or claim 16, wherein the zinc stannate is SnZnO3.

20. The apparatus of claim 15 or claim 16, wherein the niobium oxide is Nb2O5.

21. A method for fabricating at least one optical device, comprising: disposing a layer of a structural material on a surface of a substrate; disposing a patterned photoresist over the layer of the structural material, the patterned photoresist having: at least one device portion; and at least one auxiliary portion. at least one auxiliary portion, wherein each device portion and each auxiliary portion exposes an unmasked portion of the layer of structural material; and etching the unmasked portions of the layer of structural material corresponding to each device portion and each auxiliary portion, wherein the etching of the unmasked portions forms: at least one optical device having a device structure corresponding to the unmasked portions of at least one device portion; and at least one auxiliary region having an auxiliary structure corresponding to the unmasked portions of at least one auxiliary portion, wherein: the width of the unmasked portions is the same for both the at least one device portion and the at least one auxiliary portion, wherein a device critical dimension of the device structure is equal to an auxiliary critical dimension of the auxiliary structure; or the width of the unmasked portions of the auxiliary portion is greater than the width of the unmasked portions of the at least one device portion, wherein an auxiliary critical dimension of the auxiliary structure is greater than a device critical dimension of the device structure.

22. The method of claim 21, wherein the layer of structural material comprises one or more of: a titanium dioxide (Ti02)-containing material, a zinc oxide (ZnO)-containing material, a tin oxide (Sn02)-containing material, a cadmium stannate-containing material, a zinc stannate-containing material, and a silicon-containing a-Si material.

23. The method of claim 21, wherein the layer of structural material comprises one or more of: a titanium dioxide (Ti02)-containing material, a zinc oxide (ZnO)-containing material, a fluorine-doped tin oxide-containing material, a cadmium stannate-containing material, a zinc stannate-containing material, and a silicon-containing a-Si material.

24. The method of claim 22 or claim 23, wherein the zinc oxide (ZnO)-containing material is an aluminum-doped zinc oxide-containing material.

25. The method of claim 22 or claim 23, wherein the silicon-containing a-Si material is a silicon nitride (Si3N4)-containing material.

26. The method of claim 22 or claim 23, wherein the zinc stannate is SnZn03.

27. The method of claim 21, wherein the etching of the unmasked portions comprises one or more of: ion implantation, ion etching, plasma etching, and wet etching.

28. The method of claim 27, wherein the ion etching is reactive ion etching.

29. The method of claim 28, wherein the reactive ion etching is directed reactive ion etching.

Images