Metasurface structure processing method and metasurface structure
By combining mask-based parallel patterning and thin film deposition processes with deep ultraviolet lithography and inductively coupled plasma etching, the efficiency and universality issues of self-supporting bilayer metasurface fabrication have been solved, enabling low-cost, large-scale manufacturing and high-performance bilayer metasurface structures.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-04-14
AI Technical Summary
Existing technologies make it difficult to achieve mass production, high efficiency, and low cost processing of self-supporting bilayer metasurfaces, and the application range of materials is limited, especially in the visible light, near-infrared, and long-wave infrared bands.
By employing mask-based parallel patterning and thin-film deposition processes, combined with deep ultraviolet lithography and inductively coupled plasma etching, alignment is achieved through overlay alignment marks to form a high-performance bilayer metasurface structure.
This technology enables low-cost, large-scale manufacturing of self-supporting double-layer metasurfaces, improving processing efficiency and the versatility of materials across different wavelengths, reducing optical scattering loss, and enhancing product performance.
Smart Images
Figure CN121849841A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the fields of optoelectronics and micro / nano fabrication technology, and more specifically, to a metasurface structure fabrication method and a metasurface structure. Background Technology
[0002] Based on the combination of microstructures, bilayer metasurfaces can be classified into three types: stacked, embedded, and self-supporting. However, existing solutions have significant limitations in both performance and manufacturing.
[0003] Stacked and embedded structures are prone to Fresnel loss, stray coupling, and resonant interference, leading to reduced optical efficiency. In contrast, self-supporting bilayer metasurfaces can effectively avoid these problems in the visible light band, but their fabrication process heavily relies on electron beam direct writing technology—a method that, while highly accurate, suffers from low efficiency and high cost, making it difficult to achieve large-scale production. Furthermore, this structure relies on atomic layer deposition (ALD) for material growth, limiting the available material systems and currently confining its fabrication application primarily to the visible light band.
[0004] Therefore, there is currently a lack of processing solutions for self-supporting double-layer metasurfaces that can be mass-produced, highly efficient, low-cost, and applicable to different wavelengths. Summary of the Invention
[0005] The purpose of this application is to provide a metasurface structure processing method and a metasurface structure, which can be batch processed through mask-based parallel patterning and thin film deposition processes, thereby solving the problems of efficiency and universality.
[0006] In a first aspect, embodiments of this application provide a method for fabricating a metasurface structure. The method includes: providing a substrate layer including overlay alignment marks; depositing a first target dielectric material matching the operating wavelength of the metasurface structure on the substrate layer using a thin film deposition process to form a first dielectric material layer; forming a first metasurface structure layer based on the first dielectric material layer using a mask-based parallel patterning and etching process; filling the first metasurface structure layer and depositing a second target dielectric material matching the operating wavelength of the metasurface structure on the filled first metasurface structure layer using a thin film deposition process to form a second dielectric material layer; aligning based on the overlay alignment marks and forming a second metasurface structure layer aligned with the first metasurface structure layer based on the second dielectric material layer.
[0007] In this embodiment, a high-performance dual-layer metasurface structure is fabricated using alignment marks on the substrate layer. A target dielectric material matching the operating wavelength of the metasurface structure is deposited via thin-film deposition. In this process, the operating wavelength of the metasurface structure determines the thin-film deposition process and the target dielectric material, expanding the material system and enhancing wavelength versatility. The first metasurface structure layer is formed using a mask-based parallel patterning and etching process. Since multiple patterns can be generated in parallel using the mask patterning process, and the mask patterns are etched onto the target dielectric material using the etching process, this parallel processing method greatly improves processing efficiency. This solves the problems of efficiency and versatility.
[0008] In some embodiments, the mask-based parallel patterning process includes a deep ultraviolet lithography method; the etching process includes an inductively coupled plasma etching method; forming a first metasurface structure layer based on a first dielectric material layer using the mask-based parallel patterning process and the etching process includes: spin-coating photoresist on the first dielectric material layer to form a photoresist layer; exposing and developing the photoresist layer using a deep ultraviolet lithography method based on a preset mask to obtain a developed photoresist pattern; and etching the first dielectric material layer based on the photoresist pattern using an inductively coupled plasma etching method to form the first metasurface structure layer.
[0009] In this embodiment, deep ultraviolet (DUV) lithography is used to expose and develop a photoresist layer based on a pre-set mask. Since DUV lithography can project the pattern on the mask onto the photoresist layer in a single step, and ensures pattern fidelity and uniformity, it achieves low-cost, large-scale manufacturing. Inductively coupled plasma (ICP-POP) etching is then used to etch the photoresist pattern, achieving not only high-speed, high-quality etching but also significantly reducing optical scattering loss. In this process, the first metasurface structure layer is formed by combining DUV lithography and ICP-POP, improving processing efficiency and product performance.
[0010] In some embodiments, the thin film deposition process includes a plasma-enhanced chemical vapor deposition method and a magnetron sputtering method; the thin film deposition process deposits a first target dielectric material matching the operating wavelength of the metasurface structure on a substrate layer to form a first dielectric material layer, including: using the plasma-enhanced chemical vapor deposition method to deposit a first target dielectric material matching the operating wavelength of the metasurface structure on a substrate layer to obtain a first base dielectric layer; and using the magnetron sputtering method to deposit a mask layer of a predetermined thickness on the first base dielectric layer to form the first dielectric material layer.
[0011] In this embodiment, a first target dielectric material matching the operating wavelength of the metasurface structure is deposited on a substrate layer using plasma-enhanced chemical vapor deposition (PECVD). A mask layer of a predetermined thickness is then deposited on the first base dielectric layer using magnetron sputtering. This allows for free selection of the dielectric material according to the target wavelength, expanding the material system and enhancing wavelength versatility. Furthermore, combining PECVD and magnetron sputtering to form the first dielectric material layer improves the film quality, laying the foundation for the high performance of the metasurface structure.
[0012] In some embodiments, the first metasurface structure layer of the metasurface structure is formed by etching a first dielectric material layer based on a photoresist pattern using an inductively coupled plasma etching method, including: etching a mask layer based on a photoresist pattern using an inductively coupled plasma etching method to obtain a patterned mask layer; and etching a first base dielectric layer based on the patterned mask layer according to a preset etching thickness using an inductively coupled plasma etching method, and removing the patterned mask layer to form the first metasurface structure layer of the metasurface structure.
[0013] In this embodiment, an inductively coupled plasma etching method is used to etch a mask layer based on a photoresist pattern to obtain a patterned mask layer. Then, based on the patterned mask layer, a first base dielectric layer is etched according to a preset etching thickness, and the patterned mask layer is removed to form the first metasurface structure layer of the metasurface structure. This not only achieves high-speed, high-quality etching but also significantly reduces optical scattering loss, thereby improving processing efficiency and product performance.
[0014] In some embodiments, a first metasurface structure layer is filled, and a second target dielectric material matching the operating wavelength of the metasurface structure is deposited on the filled first metasurface structure layer by a thin film deposition process to form a second dielectric material layer. This includes: spin-coating a filling layer onto a substrate layer using a spin-coating process; wherein the filling layer covers the first metasurface structure layer; removing excess portions of the filling layer using an etching process; wherein the thickness of the removed filling layer is less than or equal to the thickness of the first metasurface structure layer; and depositing the second target dielectric material matching the operating wavelength of the metasurface structure on the removed filling layer by a thin film deposition process to form a second dielectric material layer.
[0015] In this embodiment, a first metasurface structure layer is filled with material, and the thickness of the filling layer is made less than or equal to that of the first metasurface structure layer through an etching process. This filler layer serves as a protective layer for the first metasurface structure layer and a support layer for the processing of the second metasurface structure layer, ensuring the execution of the processing. Furthermore, the thickness of the filling layer being less than or equal to that of the first metasurface structure layer allows direct contact between the top of the first metasurface structure layer and the bottom of the second metasurface structure layer, enabling the lower microstructure to support the upper microstructure and achieving a high-performance dual-layer microstructure.
[0016] In some embodiments, after alignment based on overlay alignment marks and the formation of a second metasurface structure layer aligned with the first metasurface structure layer on the second dielectric material layer, the method further includes: removing the removed fill layer using an etching process to form a metasurface structure based on the first metasurface structure layer and the second metasurface structure layer.
[0017] In this embodiment, after forming the second metasurface structure layer, the filling layer is removed using an etching process to generate the final metasurface structure. During this process, the etching process can accurately control the size of the residual gaps and can remove the filling layer material quickly, uniformly, and thoroughly, thereby improving the processing efficiency and performance of the metasurface structure.
[0018] In some embodiments, the filling layer is formed using thick photoresist.
[0019] In this embodiment, the thick photoresist serves as a temporary filler, possessing the advantages of simple processing, low cost, good filling properties, and good planarization, thereby achieving the goals of batch production and low cost. Furthermore, it can be effectively removed by etching processes, improving the processing efficiency and performance of metasurface structures.
[0020] Secondly, embodiments of this application provide a metasurface structure, which includes a substrate layer, a first metasurface structure layer, and a second metasurface structure layer; the first metasurface structure layer is located on the upper surface of the substrate layer, and the second metasurface structure layer is located on the upper surface of the first metasurface structure layer; wherein, the preparation method of the first metasurface structure layer and the second metasurface structure layer includes: alignment by overlay alignment marks on the substrate layer.
[0021] In this embodiment, a bilayer metasurface comprising two metasurface structures is prepared by utilizing overlay alignment marks on the substrate layer, thereby improving product quality.
[0022] In some embodiments, the first metasurface structure layer and the second metasurface structure layer are made of silicon nitride, titanium dioxide, gallium nitride or silicon; the substrate layer is made of quartz, sapphire or silicon wafer.
[0023] In this application embodiment, a variety of material selections are provided to enhance the versatility of the band, thereby improving the versatility of the processing method.
[0024] In some embodiments, the metasurface structure is prepared by the metasurface structure processing method of any embodiment of the first aspect.
[0025] In this embodiment, the metasurface structure is prepared by the above-described metasurface structure processing method, which improves processing efficiency and product quality.
[0026] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing embodiments of this application. Attached Figure Description
[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 A schematic flowchart illustrating a metasurface structure fabrication method provided in this application embodiment; Figures 2(a)-2(l) are flowcharts of a metasurface structure provided in the embodiments of this application.
[0029] Icons: A1 - Substrate, A2 - Overlay alignment marks, A3 - First photoresist layer, A4 - First hard mask layer, A5 - First base dielectric layer, A6 - Mask, A7 - Photoresist pattern, A8 - Hard mask pattern, A9 - First metasurface structure layer, A10 - Filler layer, A11 - Second photoresist layer, A12 - Second hard mask layer, A13 - Second base dielectric layer, A14 - Second metasurface structure layer, A15 - Metasurface structure. Detailed Implementation
[0030] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.
[0031] It should be noted that all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.
[0032] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.
[0033] Bilayer metasurfaces can be classified into three types based on their microstructure combination: stacked, embedded, and self-supporting. However, existing solutions have significant limitations in both performance and manufacturing. For example, stacked and embedded structures are prone to Fresnel loss, stray coupling, and resonance interference, leading to reduced optical efficiency. In contrast, self-supporting bilayer metasurfaces can effectively avoid these problems in the visible light band, but their fabrication process heavily relies on electron beam direct writing technology—a method that, while highly accurate, suffers from low efficiency and high cost, making large-scale production difficult. Furthermore, this structure relies on atomic layer deposition (ALD) for material growth, limiting the available material systems and currently confining its fabrication application primarily to the visible light band.
[0034] Therefore, there is currently a lack of a processing scheme for self-supporting bilayer metasurfaces that can achieve mass production, high efficiency, low cost, and can be used in different wavelength bands (visible light, near infrared, long-wave infrared).
[0035] To address the aforementioned problems, this application provides a metasurface structure fabrication method and a metasurface structure, which enables batch processing through mask-based parallel patterning and thin-film deposition processes, thereby solving the issues of efficiency and versatility. To facilitate understanding of the technical solution of this application, the relevant technologies used in this application are now introduced: Thin film deposition is a technique that uses physical or chemical methods to controllably grow or coat a solid thin film with a thickness ranging from nanometers to micrometers on the surface of a substrate. Its function is to provide "raw materials" for device manufacturing. It determines the material (metal, dielectric), thickness, uniformity, and fundamental optical and electrical properties of the functional layer.
[0036] In the embodiments of this application, the thin film deposition process may include, but is not limited to, the following process methods: 1. Plasma-Enhanced Chemical Vapor Deposition (PECVD): This is a technique for depositing various thin films (such as silicon dioxide, silicon nitride, and amorphous silicon) at relatively low temperatures. It utilizes plasma energy to activate and promote the chemical reaction of gaseous precursors, thereby forming a solid film on the substrate surface.
[0037] 2. Metal-Organic Chemical Vapor Deposition (MOCVD): This technique involves precisely delivering gaseous precursors, such as organometallic compounds (e.g., trimethylgallium, trimethylaluminum) and hydrides (e.g., phosphine, arsine, ammonia), onto a heated substrate surface. At high temperatures, the precursors undergo thermal decomposition, and the desired compound semiconductor crystal thin film is deposited on the substrate through a chemical reaction.
[0038] 3. Magnetron sputtering: This is a physical vapor deposition technique used to deposit metal or dielectric thin films on substrates. It has advantages such as fast deposition rate, good film adhesion, and excellent uniformity.
[0039] 4. Electron beam vapor deposition: a physical vapor deposition technique. It uses a high-energy electron beam to bombard and heat the source material, causing it to melt and evaporate (or sublimate) at high temperatures. The vapor then condenses into a thin film on a cooler substrate surface.
[0040] Mask-based parallel patterning refers to a technique that uses a pre-fabricated mask containing design patterns to transfer the patterns from the mask onto a substrate coated with a photosensitive material (photoresist) in a single, parallel process via optical or other radiation methods. This achieves "high-efficiency replication" from design to physical pattern.
[0041] In this application embodiment, the mask-based parallel patterning process may include, but is not limited to, the following process methods: 1. Deep Ultraviolet Lithography (DUV): A mainstream projection lithography technique that uses deep ultraviolet light with wavelengths of 248nm (KrF excimer laser) or 193nm (ArF excimer laser) to transfer circuit patterns onto a silicon wafer coated with photoresist through a mask. It is a key technology for manufacturing chips ranging from micrometer-scale to the vast majority of 7nm / 5nm chips.
[0042] Etching is a technique that, after patterning, selectively removes material from areas not protected by a mask, thereby precisely and permanently transferring the two-dimensional pattern on the mask to the underlying functional layer or substrate. It achieves "stereoscopic engraving" from a planar pattern to a three-dimensional structure. It determines the physical shape, sidewall morphology, and dimensional accuracy of the final device.
[0043] In this application embodiment, the etching process may include, but is not limited to, the following process methods: 1. Inductively Coupled Plasma (ICP): An advanced high-density plasma etching technology. It can independently control plasma density and ion bombardment energy, thereby achieving high etching rates, high selectivity, and anisotropic (vertical sidewall) fine etching.
[0044] 2. Reactive Ion Etching (RIE): A dry etching technique that combines physical sputtering and chemical reactions. It can achieve anisotropic and selective etching at low pressure.
[0045] 3. Wet etching: The wafer is immersed in a chemical solution or sprayed to dissolve the unprotected material through a chemical reaction.
[0046] Figure 1 This is a schematic flowchart of a metasurface structure processing method provided in an embodiment of this application, as shown below. Figure 1 As shown, the method includes: Step S101, providing a base layer including overlay alignment marks.
[0047] Overlay alignment marks are permanent physical patterns with specific shapes and high contrasts pre-fabricated on a substrate during micro-nano fabrication processes. Their core function is to provide precise spatial references for subsequent critical steps such as photolithography, etching, and deposition, ensuring nanometer-level precision overlay alignment between patterns on different layers.
[0048] In the above implementation process, a clean substrate, such as quartz, sapphire, silicon, germanium, etc., is first provided, and then alignment marks are processed and engraved on the clean substrate.
[0049] In one embodiment, the specific process for obtaining a substrate layer including alignment marks is as follows: Using a material such as quartz, sapphire, or silicon wafer as the substrate, organic matter and metal ions on the substrate are removed through standard cleaning (e.g., RCA cleaning) to obtain a clean surface. A layer of metal, typically a chemically stable metal such as chromium (Cr) or gold (Au), is deposited on the cleaned substrate surface, followed by spin-coating of a layer of photoresist. The designed alignment mark pattern is exposed onto the photoresist using electron beam writing or laser writing. The mark pattern is typically a symmetrical, high-contrast design, such as crosshairs, concentric squares, or a grating structure. The photoresist in the exposed (or unexposed) areas is then dissolved, allowing the mark pattern to form a window or mask on the photoresist. Using the photoresist as a mask, the pattern is precisely transferred to the metal layer through an etching process to form the alignment marks. Finally, any remaining photoresist is completely removed, completing the mark fabrication.
[0050] Step S102: A first target dielectric material matching the operating wavelength of the metasurface structure is deposited on the substrate layer through a thin film deposition process to form a first dielectric material layer.
[0051] After obtaining a substrate layer including overlay alignment marks, a first target dielectric material is determined based on the operating wavelength of the metasurface structure, and then a thin film deposition process is determined based on the first target dielectric material. Through the thin film deposition process, the first target dielectric material matching the operating wavelength of the metasurface structure is deposited on the substrate layer to form a first dielectric material layer.
[0052] The selection principle for dielectric materials is generally to have a high refractive index (to improve the phase modulation capability of microstructures) and a low extinction coefficient (to reduce device loss and improve device efficiency).
[0053] For example, if the operating wavelength of the metasurface structure is in the visible light band, the first target dielectric material can be titanium dioxide (TiO2) or silicon nitride (Si3N4), and the thin film deposition process can be plasma-enhanced chemical vapor deposition, metal-organic chemical vapor deposition, or magnetron sputtering. If the operating wavelength of the metasurface structure is in the infrared band, the first target dielectric material can be zinc sulfide (ZnS), zinc selenide (ZnSe), or silicon (Si), and the thin film deposition process can be magnetron sputtering, electron beam evaporation deposition, or metal-organic chemical vapor deposition.
[0054] Step S103: A first metasurface structure layer is formed based on the first dielectric material layer by using a mask-based parallel patterning and etching process.
[0055] After depositing a first dielectric material layer on the substrate, a first metasurface structure layer is formed based on the first dielectric material layer through a mask-based parallel patterning and etching process.
[0056] Specifically, photoresist is spin-coated onto the first dielectric material layer to form a photoresist layer; based on a preset mask, the photoresist layer is exposed and developed using a mask-based parallel patterning process to obtain a developed photoresist pattern; using an etching process, the first dielectric material layer is etched based on the photoresist pattern to form the first metasurface structure layer of the metasurface structure.
[0057] The mask-based parallel patterning process and etching process can be selected according to the actual situation. In one embodiment, the mask-based parallel patterning process is a deep ultraviolet lithography method; the etching process is an inductively coupled plasma etching method.
[0058] In this process, deep ultraviolet (DUV) lithography is used to expose and develop the photoresist layer based on a pre-set mask. Because DUV lithography can project the pattern on the mask onto the photoresist layer in a single step, ensuring pattern fidelity and uniformity, it achieves low-cost, large-scale manufacturing. Inductively coupled plasma (ICP-POP) etching is then used to etch the photoresist pattern, achieving high-speed, high-quality etching and significantly reducing optical scattering losses. Furthermore, by combining DUV lithography and ICP-POP etching to form the first metasurface structure layer, processing efficiency and product performance are improved.
[0059] Step S104: The first metasurface structure layer is filled, and a second target dielectric material matching the working wavelength of the metasurface structure is deposited on the filled first metasurface structure layer by a thin film deposition process to form a second dielectric material layer.
[0060] Since the first metasurface structure layer obtained after the mask-based parallel patterning and etching process is already in the shape of a mask, in order to protect the first metasurface structure layer and to process the second metasurface structure layer on the first metasurface structure layer, the first metasurface structure layer is filled after processing to obtain the filled first metasurface structure layer, thereby providing support for the formation of the second metasurface structure.
[0061] Based on this, a second target dielectric material matching the working wavelength of the metasurface structure is deposited on the first metasurface structure layer after filling by a thin film deposition process, forming a second dielectric material layer.
[0062] It should be noted that, based on the functional design of the double-layer metasurface, the dielectric materials of the two metasurfaces can be the same or different. That is, the first target dielectric material and the second target dielectric material can be the same or different.
[0063] Based on this, the thin film deposition process for forming the second dielectric material layer can be the same as or different from the thin film deposition process for forming the first dielectric material layer. The specific choice should be made according to the actual processing conditions.
[0064] Step S105: Alignment is performed based on the overlay alignment marks, and a second metasurface structure layer is formed that is aligned with the first metasurface structure layer according to the second dielectric material layer.
[0065] After the second dielectric material layer is formed, alignment is performed based on the overlay alignment marks, and a second metasurface structure layer aligned with the first metasurface structure layer is formed based on the second dielectric material layer through a mask-based parallel patterning and etching process.
[0066] It should be noted that the mask-based parallel patterning and etching processes used to form the second metasurface structure layer can be the same as or different from those used to form the first metasurface structure layer, depending on the specific processing conditions.
[0067] However, it should be noted that since the underlying material for the growth and etching of the first metasurface structure layer is the substrate, such as quartz, sapphire, silicon wafer, germanium wafer, etc., while the underlying material for the growth and etching of the second metasurface structure layer is the first metasurface structure layer after filling, the first metasurface structure layer after filling needs more protection than the substrate. Therefore, the process parameters for growing and etching the second metasurface structure layer need to consider lower power, temperature, etc., to ensure minimal damage to the first metasurface structure layer after filling.
[0068] For example, in a bilayer metasurface structure, both dielectric materials are titanium dioxide (TiO2), and both are deposited using plasma-enhanced chemical vapor deposition. Because the first deposition substrate is quartz or sapphire, which are conventional substrates, higher power and higher temperature process parameters can be used to ensure a higher deposition rate. However, for the second layer, since it is deposited on top of the first metasurface structure layer after it has been filled, the deposition temperature and power are reduced to protect the first metasurface structure layer from damage during the fabrication of the second layer.
[0069] Similarly, in the material etching process, inductively coupled plasma etching technology is used. Since the bottom of the first layer is the substrate, which is a natural barrier layer, the etching parameters can be appropriately coarse to ensure etching efficiency. The second layer is the first metasurface structure layer after filling. When etching, especially when etching close to the first metasurface structure layer after filling, the etching rate may need to be appropriately reduced to reduce the impact on the first metasurface structure layer after filling.
[0070] However, if processing efficiency is not a concern, it is also feasible to process both layers using the same milder process parameters.
[0071] Therefore, the specific applicable processing technology and processing parameters are adaptively selected and determined according to the actual processing conditions, and this application does not make specific limitations in this regard.
[0072] In the above implementation process, by first processing the lower layer, filling, and then depositing and processing the upper layer, a self-supporting double-layer alignment structure is finally formed, which ensures the performance of the metasurface structure.
[0073] In this embodiment, a high-performance dual-layer metasurface structure is fabricated using alignment marks on the substrate layer. A target dielectric material matching the operating wavelength of the metasurface structure is deposited via thin-film deposition. In this process, the operating wavelength of the metasurface structure determines the thin-film deposition process and the target dielectric material, expanding the material system and enhancing wavelength versatility. The first metasurface structure layer is formed using a mask-based parallel patterning and etching process. Since multiple patterns can be generated in parallel using the mask patterning process, and the mask patterns are etched onto the target dielectric material using the etching process, this parallel processing method greatly improves processing efficiency. This solves the problems of efficiency and versatility.
[0074] In some embodiments, the thin film deposition process includes a plasma-enhanced chemical vapor deposition method and a magnetron sputtering method; the thin film deposition process deposits a first target dielectric material matching the operating wavelength of the metasurface structure on a substrate layer to form a first dielectric material layer, including: using the plasma-enhanced chemical vapor deposition method to deposit a first target dielectric material matching the operating wavelength of the metasurface structure on a substrate layer to obtain a first base dielectric layer; and using the magnetron sputtering method to deposit a mask layer of a predetermined thickness on the first base dielectric layer to form the first dielectric material layer.
[0075] In the above implementation process, to achieve "high-fidelity and high-precision" pattern transfer from photoresist pattern to final dielectric material structure, when forming the first dielectric material layer, a first target dielectric material matching the working wavelength of the metasurface structure is first deposited on the substrate layer using plasma-enhanced chemical vapor deposition to obtain the first base dielectric layer. Then, a mask layer of a predetermined thickness is deposited on the first base dielectric layer using magnetron sputtering to form the first dielectric material layer based on the first base dielectric layer and the mask layer.
[0076] The mask layer can be made of chromium (Cr), aluminum, nickel, or other materials. The preset thickness is a pre-defined value. For example, a 50 nm Cr layer is deposited on the first base dielectric layer using magnetron sputtering as a hard mask.
[0077] In this embodiment, a first target dielectric material matching the operating wavelength of the metasurface structure is deposited on a substrate layer using plasma-enhanced chemical vapor deposition (PECVD). A mask layer of a predetermined thickness is then deposited on the first base dielectric layer using magnetron sputtering. This allows for free selection of the dielectric material according to the target wavelength, expanding the material system and enhancing wavelength versatility. Furthermore, combining PECVD and magnetron sputtering to form the first dielectric material layer improves the film quality, laying the foundation for the high performance of the metasurface structure.
[0078] In some embodiments, the first metasurface structure layer of the metasurface structure is formed by etching a first dielectric material layer based on a photoresist pattern using an inductively coupled plasma etching method, including: etching a mask layer based on a photoresist pattern using an inductively coupled plasma etching method to obtain a patterned mask layer; and etching a first base dielectric layer based on the patterned mask layer according to a preset etching thickness using an inductively coupled plasma etching method, and removing the patterned mask layer to form the first metasurface structure layer of the metasurface structure.
[0079] In the above implementation process, since the mask layer is above the first base dielectric layer, the etching is performed from top to bottom. Therefore, the inductively coupled plasma etching method is used to first etch the mask layer based on the photoresist pattern to obtain a patterned mask layer. Then, the inductively coupled plasma etching method is used to etch the first base dielectric layer based on the patterned mask layer according to a preset etching thickness, and the patterned mask layer is removed to form the first metasurface structure layer of the metasurface structure.
[0080] The preset etching thickness is determined based on the refractive index of the material of the first base dielectric layer and the function of the metasurface structure.
[0081] For example, if the operating wavelength of the metasurface structure is in the visible light band, and the material of the first base dielectric layer is titanium dioxide (TiO2) or silicon nitride (Si3N4), then the preset etching thickness is usually around 800 nanometers (nm) to 1 micrometer (µm). If the operating wavelength of the metasurface structure is in the long-wave infrared band, and the material of the first base dielectric layer is zinc sulfide (ZnS), then the preset etching thickness is usually several micrometers (µm).
[0082] In this embodiment, an inductively coupled plasma etching method is used to etch a mask layer based on a photoresist pattern to obtain a patterned mask layer. Then, based on the patterned mask layer, a first base dielectric layer is etched according to a preset etching thickness, and the patterned mask layer is removed to form the first metasurface structure layer of the metasurface structure. This not only achieves high-speed, high-quality etching but also significantly reduces optical scattering loss, thereby improving processing efficiency and product performance.
[0083] In one embodiment, if the material of the substrate layer matches the operating wavelength of the metasurface structure, then the substrate layer is used as the first basic dielectric layer. That is, the step of "depositing a first target dielectric material matching the operating wavelength of the metasurface structure on the substrate layer using plasma-enhanced chemical vapor deposition to obtain the first basic dielectric layer" is omitted. Instead, a mask layer of a predetermined thickness is directly deposited on the substrate layer using magnetron sputtering to form the first dielectric material layer based on the substrate layer and the mask layer.
[0084] For example, if the substrate material is silicon, and the target dielectric material determined according to the working wavelength of the metasurface structure is also silicon, the substrate can be directly used as the first basic dielectric layer as the basis for subsequent processing.
[0085] In this method, during processing, photoresist is spin-coated onto a mask layer to form a photoresist layer; based on a preset mask, the photoresist layer is exposed and developed using a mask-based parallel patterning process to obtain a developed photoresist pattern; then, using inductively coupled plasma etching (ICP-E) to etch the mask layer based on the photoresist pattern, a patterned mask layer is obtained; using ICP-E, based on the patterned mask layer, the substrate layer is etched according to a preset etching thickness using ICP-E, and the patterned mask layer is removed to form a first metasurface structure layer on the substrate layer.
[0086] In some embodiments, a first metasurface structure layer is filled, and a second target dielectric material matching the operating wavelength of the metasurface structure is deposited on the filled first metasurface structure layer by a thin film deposition process to form a second dielectric material layer. This includes: spin-coating a filling layer onto a substrate layer using a spin-coating process; wherein the filling layer covers the first metasurface structure layer; removing excess portions of the filling layer using an etching process; wherein the thickness of the removed filling layer is less than or equal to the thickness of the first metasurface structure layer; and depositing the second target dielectric material matching the operating wavelength of the metasurface structure on the removed filling layer by a thin film deposition process to form a second dielectric material layer.
[0087] In the above implementation process, the first metasurface structure layer is filled to form a filling layer. During filling, to protect the first metasurface structure layer, the thickness of the filling layer is initially greater than the thickness of the first metasurface structure layer. For example, the thickness of the filling layer is approximately 1.2 to 1.5 times the thickness of the first metasurface structure layer.
[0088] In order to ensure that the second metasurface structure layer grows stably on top of the first metasurface structure layer, and to ensure that the filling layer supports the processing of the second metasurface structure layer, the filling layer is etched after filling is completed. The portion of the filling layer that is higher than the first metasurface structure layer is removed, so that the thickness of the removed filling layer is less than or equal to the thickness of the first metasurface structure layer, thereby exposing the top of the first metasurface structure layer and allowing it to come into contact with the second metasurface structure layer.
[0089] It should be noted that the range of less than is within 3%.
[0090] In addition, the filler material and the two dielectric layers should have a high etching selectivity to ensure that the microstructure of the two dielectric layers is not damaged when the filler layer is removed later.
[0091] In some embodiments, the filler layer is formed using thick photoresist. Thick photoresist refers to a special type of photoresist whose thickness typically ranges from a few micrometers to several hundred micrometers.
[0092] The process for forming the second metasurface structure layer is the same as that for forming the first metasurface structure layer, and will not be described in detail here.
[0093] In this embodiment, a first metasurface structure layer is filled with material, and the thickness of the filling layer is made less than or equal to that of the first metasurface structure layer through an etching process. This filler layer serves as a protective layer for the first metasurface structure layer and a support layer for the processing of the second metasurface structure layer, ensuring the execution of the processing. Furthermore, the thickness of the filling layer being less than or equal to that of the first metasurface structure layer allows direct contact between the top of the first metasurface structure layer and the bottom of the second metasurface structure layer, enabling the lower microstructure to support the upper microstructure and achieving a high-performance dual-layer microstructure.
[0094] In some embodiments, after alignment based on overlay alignment marks and the formation of a second metasurface structure layer aligned with the first metasurface structure layer on the second dielectric material layer, the method further includes: removing the removed fill layer using an etching process to form a metasurface structure based on the first metasurface structure layer and the second metasurface structure layer.
[0095] In the above implementation process, the etching process for removing the filling layer can be wet removal, or dry removal such as inductively coupled plasma etching or reactive ion etching.
[0096] In this embodiment, after forming the second metasurface structure layer, the filling layer is removed using an etching process to generate the final metasurface structure. During this process, the etching process can accurately control the size of the residual gaps and can remove the filling layer material quickly, uniformly, and thoroughly, thereby improving the processing efficiency and performance of the metasurface structure.
[0097] Figures 2(a)-2(l) are flowcharts illustrating the fabrication process of a metasurface structure according to an embodiment of this application. As shown in Figures 2(a)-2(l), the fabrication process of the metasurface structure is as follows: Step 1: As shown in Figure 2(a), provide a clean substrate A1, such as quartz, sapphire, or silicon wafer.
[0098] Step 2: As shown in Figure 2(b), alignment mark A2 is machined on a clean substrate.
[0099] Step 3: As shown in Figure 2(c), according to the working wavelength of the metasurface structure, a corresponding dielectric material is deposited on the above substrate using plasma-enhanced chemical vapor deposition to form the first basic dielectric layer A5. Examples include titanium dioxide (TiO2), silicon nitride (Si3N4), and silicon (Si).
[0100] Step 4: As shown in Figure 2(c), a 50nm chromium layer is deposited on the first base dielectric layer by magnetron sputtering as a hard mask to form the first hard mask layer A4, and photoresist is spin-coated on the first hard mask layer A4 to form the first photoresist layer A3.
[0101] Step 5: As shown in Figure 2(d), a photoresist pattern A7 is formed on the first photoresist layer A3 based on the mask A6 using deep ultraviolet lithography.
[0102] Step 6: As shown in Figure 2(e), the photoresist pattern A7 is transferred to the hard mask layer A4 using inductively coupled plasma etching process, and the residual photoresist is removed to form the hard mask pattern A8.
[0103] Step 7: As shown in Figures 2(f) and 2(g), the hard mask pattern A8 is transferred to the first base dielectric layer A5 deposited in step 3 using inductively coupled plasma etching. The etching thickness is the height h1 of the microstructure designed for the first metasurface structure layer. The remaining hard mask pattern A8 is removed using inductively coupled plasma etching to form the first metasurface structure layer A9.
[0104] Step 8: As shown in Figures 2(h) and 2(i), a filler layer A10 is spin-coated onto the first metasurface structure layer A9 using a spin-coating process. Thick photoresist can be used, with a filler thickness of h0 (h0 is approximately 1.2 to 1.5 times h1). After filling, the top layer photoresist is removed using reactive ion etching. The thickness of the removed photoresist can be h0-h1, or it can be over-etched appropriately to ensure that the upper surface of the first metasurface structure layer is exposed.
[0105] Step 9: As shown in Figure 2(j), a medium material is deposited on the first metasurface structure layer after filling using a plasma-enhanced chemical vapor deposition process to form the second basic medium layer A13.
[0106] Step 10: As shown in Figure 2(j), a 50nm chromium layer is deposited on the second base dielectric layer A13 by magnetron sputtering or electron beam evaporation as a hard mask to form a second hard mask layer A12, and photoresist is spin-coated on the second hard mask layer A12 to form a second photoresist layer A11.
[0107] Step 11: Using deep ultraviolet lithography, form a photoresist pattern on the second photoresist layer A11 based on the mask; Step 12: Use inductively coupled plasma etching to transfer the photoresist pattern to the second hard mask layer A12 and remove the residual photoresist to form the hard mask pattern.
[0108] Step 13: As shown in Figure 2(k), the hard mask pattern is transferred to the second base dielectric layer A13 deposited in step 9 using inductively coupled plasma etching. The etching thickness is the height h2 of the microstructure designed for the second metasurface structure layer. The remaining hard mask is removed using inductively coupled plasma etching to form the second metasurface structure layer A14.
[0109] Step 14: As shown in Figure 2(l), reactive ion etching is used to remove the filler layer photoresist from step 8 spin-coated to form the final metasurface structure A15.
[0110] In some embodiments, as shown in FIG2(l), this application provides a metasurface structure, the metasurface structure A15 including a substrate layer A1, a first metasurface structure layer A9 and a second metasurface structure layer A14; the first metasurface structure layer A9 is located on the upper surface of the substrate layer A1, and the second metasurface structure layer A14 is located on the upper surface of the first metasurface structure layer A9; wherein, the preparation method of the first metasurface structure layer A9 and the second metasurface structure layer A4 includes: alignment by overlay alignment mark A2 on the substrate layer.
[0111] In this embodiment, a bilayer metasurface comprising two metasurface structures is prepared by utilizing overlay alignment marks on the substrate layer, thereby improving product quality.
[0112] In some embodiments, the first metasurface structure layer A9 and the second metasurface structure layer A14 are made of silicon nitride, titanium dioxide, gallium nitride or silicon; the substrate layer is made of quartz, sapphire or silicon wafer.
[0113] In this application embodiment, a variety of material selections are provided to enhance the versatility of the band, thereby improving the versatility of the processing method.
[0114] In some embodiments, the metasurface structure is prepared by the metasurface structure processing method of any of the above embodiments.
[0115] In this embodiment, the metasurface structure is prepared by the above-described metasurface structure processing method, which improves processing efficiency and product quality.
[0116] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.
[0117] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.
[0118] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.
[0119] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. A method for processing metasurface structures, characterized in that, The method includes: Provides a base layer including overlay alignment marks; A first target dielectric material matching the operating wavelength of the metasurface structure is deposited on the substrate layer by a thin film deposition process to form a first dielectric material layer. The first metasurface structure layer of the metasurface structure is formed based on the first dielectric material layer through a mask-based parallel patterning and etching process. The first metasurface structure layer is filled, and a second target dielectric material matching the working wavelength of the metasurface structure is deposited on the filled first metasurface structure layer by a thin film deposition process to form a second dielectric material layer. Alignment is performed based on the overlay alignment marks, and a second metasurface structure layer is formed according to the second dielectric material layer, which is aligned with the first metasurface structure layer.
2. The method according to claim 1, characterized in that, in, The mask-based parallel patterning process includes deep ultraviolet lithography; the etching process includes inductively coupled plasma etching. The first metasurface structure layer, formed based on the first dielectric material layer using a mask-based parallel patterning and etching process, comprises: Photoresist is spin-coated onto the first dielectric material layer to form a photoresist layer; Based on a preset mask, the photoresist layer is exposed and developed using the deep ultraviolet lithography method to obtain the developed photoresist pattern. Using the inductively coupled plasma etching method, the first dielectric material layer is etched based on the photoresist pattern to form the first metasurface structure layer of the metasurface structure.
3. The method according to claim 2, characterized in that, in, The thin film deposition process includes plasma-enhanced chemical vapor deposition and magnetron sputtering. The first dielectric material layer is formed by depositing a first target dielectric material matching the operating wavelength of the metasurface structure on the substrate layer through a thin film deposition process, including: Using the plasma-enhanced chemical vapor deposition method, a first target dielectric material matching the operating wavelength of the metasurface structure is deposited on the substrate layer to obtain a first base dielectric layer; Using the magnetron sputtering method, a mask layer of a predetermined thickness is deposited on the first base dielectric layer to form the first dielectric material layer.
4. The method according to claim 3, characterized in that, The method of etching the first dielectric material layer based on the photoresist pattern using the inductively coupled plasma etching method to form the first metasurface structure layer of the metasurface structure includes: Using the inductively coupled plasma etching method, the mask layer is etched based on the photoresist pattern to obtain a patterned mask layer; Using the inductively coupled plasma etching method, the first base dielectric layer is etched according to a preset etching thickness based on the patterned mask layer, and the patterned mask layer is removed to form the first metasurface structure layer of the metasurface structure.
5. The method according to any one of claims 1-4, characterized in that, The process of filling the first metasurface structure layer and depositing a second target dielectric material matching the operating wavelength of the metasurface structure on the filled first metasurface structure layer through a thin film deposition process to form a second dielectric material layer includes: A filler layer is spin-coated onto the substrate layer using a spin-coating process; wherein the filler layer covers the first metasurface structure layer; The excess portion of the filling layer is removed using the etching process; wherein the thickness of the removed filling layer is less than or equal to the thickness of the first metasurface structure layer. Through the thin film deposition process, a second target dielectric material matching the operating wavelength of the metasurface structure is deposited on the removed filler layer to form a second dielectric material layer.
6. The method according to claim 5, characterized in that, After aligning based on the overlay alignment marks and forming a second metasurface structure layer on the second dielectric material layer that is aligned with the first metasurface structure layer, the method further includes: The etching process is used to remove the filler layer after removal, so as to form the metasurface structure based on the first metasurface structure layer and the second metasurface structure layer.
7. The method according to claim 5, characterized in that, in, The filling layer is formed using thick photoresist.
8. A metasurface structure, characterized in that, The metasurface structure includes a substrate layer, a first metasurface structure layer, and a second metasurface structure layer; The first metasurface structure layer is located on the upper surface of the substrate layer, and the second metasurface structure layer is located on the upper surface of the first metasurface structure layer; The preparation method of the first metasurface structure layer and the second metasurface structure layer includes: alignment by overlay alignment marks on the substrate layer.
9. The metasurface structure according to claim 8, characterized in that, The first and second metasurface structure layers are made of silicon nitride, titanium dioxide, gallium nitride, or silicon; the substrate layer is made of quartz, sapphire, or silicon wafer.
10. The metasurface structure according to claim 8 or 9, characterized in that, The metasurface structure is prepared by any one of the metasurface structure processing methods described in claims 1-7.