A manufacturing method of a metasurface optical element

Abstract

An embodiment of the present application discloses a manufacturing method of a metasurface optical element, including: depositing a nano material on the end face of a substrate so that the nano material covers the entire end face of the substrate; etching a part of the nano material to the end face of the substrate and retaining another part of the nano material to obtain a discrete nano pillar structure; filling a protective material in the gaps of the discrete nano pillar structure; etching the protective material in the gaps of the discrete nano pillar structure so that the height of the protective material in each gap is uniform and less than the height of the discrete nano pillar structure to obtain a metasurface optical element. In the present application, by depositing a protective material in the gaps of the discrete nano pillar structure, the mechanical stability of the nano pillar structure is enhanced; by controlling the height of the protective material to be less than the height of the nano pillar, the relative refractive index difference between the upper half of the exposed nano pillar structure and the surrounding environment is ensured; a glass wafer is bonded to the top of the nano pillar to protect the nano pillar from external damage; a support material is used to support the glass wafer to prevent it from contacting the nano pillar and causing wear.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of semiconductor technology, and in particular, to a method for manufacturing a metasurface optical element. Background Art

[0002] A metasurface optical element is composed of a substrate and discrete nanocolumn structures disposed on the surface of the substrate. Through different materials, different structures, and / or different arrangement manners between the discrete nanocolumn structures, various different optical functions can be realized, such as optical focusing, imaging, polarization control, aberration control, and spectral control. Therefore, metasurface devices are often used in display devices, optical computing devices, and the like.

[0003] During the use of the metasurface optical element, the metasurface optical element may be bumped. Since the mechanical stability of the nanocolumns themselves may be poor, or the nanocolumns and the substrate may not be tightly bonded due to different materials of the nanocolumns and the substrate, the nanocolumns on the surface of the substrate are easily damaged or toppled, affecting the optical performance and service life of the metasurface device. Based on this, a method of plating a protective material around the nanocolumns is usually adopted to protect the nanocolumns and increase the mechanical stability of the nanocolumns.

[0004] However, since the difference in refractive index between the protective material and the nanomaterial is relatively small, the relative refractive index of the metasurface optical element is small, increasing the design difficulty of the metasurface optical element and affecting the use effect of the metasurface optical element. Based on this, how to ensure the relative refractive index of the metasurface optical element with the working environment while enhancing the stability of the nanocolumns in the metasurface optical element is an urgent problem to be solved in the art. Summary of the Invention

[0005] The embodiments of the present application provide a method for manufacturing a metasurface optical element, which can enhance the mechanical stability of the nanocolumns while ensuring the relative refractive index of the metasurface optical element with the working environment.

[0006] In a first aspect, the embodiments of the present application provide a method for manufacturing a metasurface optical element, the method comprising:

[0007] Plating a nanomaterial on the end face of the substrate such that the nanomaterial covers the entire end face of the substrate;

[0008] Etching a part of the nanomaterial to the end face of the substrate and retaining another part of the nanomaterial to obtain discrete nanocolumn structures;

[0009] Filling a protective material in the gaps between the discrete nanocolumn structures by using a film growth process;

[0010] A dry selective etching process is used to remove the protective material in part of the gaps of the discrete nanocolumn structure, so that the height of the protective material in all gaps is uniform and less than the height of the discrete nanocolumn structure, and the metasurface optical element is obtained.

[0011] In an alternative design, after etching the protective material in the gaps of the discrete nanocolumn structure, it further includes:

[0012] Bond a glass wafer to the top of the discrete nanocolumn structure to protect the discrete nanocolumn structure.

[0013] In an alternative design, after depositing a nanomaterial on the end face of the substrate, it further includes:

[0014] Deposit a support material on the end face of the nanomaterial so that the support material covers the entire end face of the nanomaterial;

[0015] Etch part of the support material to the end face of the nanomaterial, and retain another part of the support material.

[0016] In an alternative design, retaining another part of the support material includes:

[0017] Use at least one nanocolumn in the discrete nanocolumn structure as the frame of the metasurface optical element;

[0018] Retain the support material above the end face of the frame.

[0019] In an alternative design, it further includes:

[0020] Bond a glass wafer to the top of the support material to obtain the metasurface optical element.

[0021] In an alternative design, before depositing a nanomaterial on the end face of the substrate, it further includes:

[0022] Deposit a stop material on the end face of the substrate, and the stop material is used to terminate etching;

[0023] Deposit a second nanomaterial on the end face of the stop material to obtain a second nanomaterial covering the entire end face of the stop material;

[0024] Etch part of the second nanomaterial;

[0025] Deposit a first layer of nanomaterial on the end face of the stop material exposed after etching to obtain the substrate.

[0026] In an alternative design, etching part of the second nanomaterial includes:

[0027] Etch a part of the second nanomaterial to the stop material and retain another part of the second nanomaterial;

[0028] Take the projection of the gap of the discrete nanocolumn structure on the bottom end face of the substrate as the first projection;

[0029] Take the projection of the retained second nanomaterial on the bottom end face of the substrate as the second projection;

[0030] The second projection is located within the first projection, and the area of the second projection is smaller than the area of the first projection.

[0031] In an alternative design, the materials used as the protective material include: silicon dioxide, plastic, titanium dioxide, silicon, germanium, silicon nitride, gallium nitride.

[0032] In an alternative design, the materials used as the nanomaterial include: silicon dioxide, crystalline silicon, amorphous silicon, germanium, titanium dioxide, silicon nitride, gallium nitride, optically transparent organic substances.

[0033] A method for manufacturing a metasurface optical element provided in this application. By depositing a nanomaterial on the end face of a substrate, the nanomaterial covers the entire end face of the substrate; etch a part of the nanomaterial to the end face of the substrate and retain another part of the nanomaterial to obtain a discrete nanocolumn structure; deposit a protective material in the gaps of the discrete nanocolumn structure; etch the protective material in the gaps of the discrete nanocolumn structure so that the height of the protective material in each gap is uniform and less than the height of the discrete nanocolumn structure to obtain the metasurface optical element. By depositing a protective material in the gaps of the nanocolumns, it plays a supporting role for the nanocolumns and enhances the mechanical stability of the nanocolumns. At the same time, the height of the protective material is less than the height of the nanocolumns, ensuring the relative refractive index between the upper exposed nanocolumns and the working environment. Description of the Drawings

[0034] To more clearly illustrate the technical solutions of this application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 It is a flowchart of a method for manufacturing a metasurface optical element provided in an embodiment of this application;

[0036] Figure 2 It is a flowchart of the first exemplary implementation manner provided in an embodiment of this application;

[0037] Figure 3 It is a flowchart of the second exemplary implementation manner provided in an embodiment of this application;

[0038] Figure 4 It is a flowchart of the third exemplary implementation manner provided by the embodiments of the present application;

[0039] Figure 5 It is a flowchart of the fourth exemplary implementation manner provided by the embodiments of the present application;

[0040] Figure 6 It is a flowchart of the fifth exemplary implementation manner provided by the embodiments of the present application.

[0041] Figures 2 to 6 The components indicated by the reference numerals in [reference numeral part] are: 1 substrate, 2 nanomaterial, 3 photoresist, 4 protective material, 5 glass wafer, 6 support material, 7 blocking material, 8 second nanomaterial. Specific implementation manner

[0042] Next, the technical solutions of the embodiments of the present application will be described with reference to the accompanying drawings in the embodiments of the present application.

[0043] The terms used in the following embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. As used in the specification and appended claims of the present application, the singular forms "a", "an", "the", "above", "said", "this" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that although the terms first, second, etc. may be used in the following embodiments to describe a certain type of object, the object should not be limited to these terms. These terms are only used to distinguish specific objects of this type of object. For example, the terms first, second, etc. may be used in the following embodiments to describe materials, but the materials should not be limited to these terms. These terms are only used to distinguish different materials. The same applies to other types of objects that may be described by the terms first, second, etc. in the following embodiments, and will not be repeated here.

[0044] The embodiments of the present application provide a method for manufacturing a metasurface optical element, which can enhance the mechanical stability of the nanocolumns while ensuring the relative refractive index between the metasurface optical element and the working environment.

[0045] The following introduces a method for manufacturing a metasurface optical element involved in the embodiments of the present application through several implementation manners.

[0046] As Figure 1 shown, Figure 1 illustrates a method 100 for manufacturing a metasurface optical element (hereinafter referred to as method 100), and method 100 includes the following steps:

[0047] Step S101, deposit a nanomaterial 2 on the end face of the substrate 1 so that the nanomaterial 2 covers the entire end face of the substrate 1.

[0048] Step S102, etch part of the nanomaterial 2 to the end face of the substrate 1, and retain another part of the nanomaterial 2 to obtain a discrete nanocolumn structure.

[0049] Step S103, fill a protective material 4 in the gaps of the discrete nanocolumn structure.

[0050] Step S104, etch the protective material 4 in the gaps of the discrete nanocolumn structure so that the height of the protective material 4 in the gaps of the discrete nanocolumn structure is uniform and less than the height of the discrete nanocolumn structure, to obtain the metasurface optical element.

[0051] For ease of understanding, the method 100 is described in detail below with reference to examples.

[0052] As Figure 2 shown, Figure 2 illustrates a specific implementation of the method 100. In this embodiment, a layer of nanomaterial 2 is first deposited on the substrate 1 so that the nanomaterial 2 covers the entire end face of the substrate 1. Then, a layer of photoresist 3 is deposited on the nanomaterial 2. According to the preset position information of the nanocolumns, etching is performed, and the remaining nanomaterial 2 is the discrete nanocolumn structure that constitutes the metasurface optical element. After that, a protective material 4 is deposited in the gaps of the discrete nanocolumn structure. In order to make the protective material 4 completely fill the gaps of the nanocolumns, the protective material 4 can overflow when depositing the protective material 4, that is, the height of the deposited protective material 4 is greater than the height of the discrete nanocolumn structure, to ensure that the protective material 4 can completely fill the gaps between the discrete nanocolumn structures. Finally, chemical mechanical polishing is used to level and selectively etch the protective material 4 in the gaps of the nanocolumns so that the height of the protective material 4 is uniform and less than the height of the discrete nanocolumns, to obtain the metasurface optical element.

[0053] In this embodiment, by filling the protective material 4 in the gaps between the discrete nanocolumn structures, it plays a role in supporting the nanocolumns, effectively preventing the nanocolumns from toppling and increasing the mechanical stability of the nanocolumns. In addition, the height of the protective material 4 is less than the height of the nanocolumns. Since the refractive index difference between the nanomaterial 2 and the protective material 4 is small, while the refractive index contrast between the nanomaterial 2 and air or other working environments is large, it makes the upper half of the nanocolumns alternate with the nanomaterial 2 and air, thus ensuring the relative refractive index between the metasurface optical element and the working environment.

[0054] Figure 2The illustrated embodiment is merely an optional embodiment of the embodiments of the present invention and does not constitute a limitation on the manufacturing method of the embodiments of the present application. In other embodiments, the technical solution of the present invention also provides other embodiments. For example, the preparation of the nanostructure can be obtained by a top-down etching process, including coating a photoresist 3 or other photosensitive materials on the nanostructure 2, and then forming a structural pattern by using techniques such as electron beam direct writing, maskless lithography, mask contact exposure, or mask projection exposure, and then fabricating the nanostructure by using a dry or wet etching process; the preparation of the nanostructure can also be obtained by a bottom-up growth process. A hole structure opposite to the columnar structure is fabricated on the photoresist 3 or the hard mask, and the nanostructure 2 is filled in the holes by using a growth process, and then the photoresist 3 or the hard mask is peeled off to obtain the nanocolumn structure.

[0055] In some embodiments of the present invention, the materials used as the protective material 4 include but are not limited to: silicon dioxide, plastic, titanium dioxide, silicon, germanium, silicon nitride, gallium nitride, etc.

[0056] In all embodiments of the present invention, the materials used as the nanostructure 2 include but are not limited to: optical materials such as silicon dioxide, crystalline silicon, amorphous silicon, germanium, titanium dioxide, silicon nitride, gallium nitride, and optically transparent organic substances with relatively high refractive indices and low losses.

[0057] In this embodiment, the material used as the protective material 4 can be a conventional protective material, including but not limited to silicon dioxide, plastic, etc., but it can also be other protective materials 4. At the same time, the material used as the protective material 4 can also be the nanostructure 2, including but not limited to titanium dioxide, silicon, etc. When the protective material 4 and the nanostructure 2 of the nanocolumn are the same, due to the stronger bonding force between different molecules of the same material, the supporting effect of the protective material 4 on the nanocolumn is stronger, making the mechanical stability of the nanocolumn stronger, and because it is the same material, the temperature stability is better.

[0058] As Figure 3 In the illustrated embodiment, the protective material 4 is the same as the nanostructure 2. In this embodiment, a thin film of the nanostructure 2 is first plated on the end face of the substrate 1; a part of the nanostructure 2 is etched so that the height of the etched part of the nanostructure 2 is less than the thickness of the plated nanostructure, and a metasurface optical element is obtained. By making the protective material 4 and the nanostructure 2 the same, not only the manufacturing steps are simplified, but also the mechanical stability and temperature stability of the nanocolumn are enhanced.

[0059] For the sake of distinction, in other embodiments of the present invention, the protective material 4 is different from the nanostructure 2.

[0060] In some embodiments of the present invention, after etching the protective material 4, it further includes:

[0061] Bond a glass wafer 5 to the top of the discrete nanocolumn structure to protect the discrete nanocolumn structure.

[0062] As Figure 4 shown, first deposit a layer of nanomaterial 2 on the end face of the substrate 1, and then etch the nanomaterial 2 to obtain a discrete nanocolumn structure. The steps of depositing a protective material 4 in the gaps of the discrete nanocolumn structure and etching are omitted here, which have been introduced in detail above and will not be elaborated here. Finally, bond a glass wafer 5 to the top of the discrete nanocolumn structure to protect the nanocolumns.

[0063] In this embodiment, by bonding a glass wafer 5 to the top of the discrete nanocolumn structure, the nanocolumns can be protected from external damage, effectively avoiding the damage of the nanocolumns caused by the collision of the metasurface optical element during use, and extending the service life.

[0064] In some embodiments of the present invention, after depositing the nanomaterial 2 on the end face of the substrate 1, it further includes:

[0065] Deposit a support material 6 on the end face of the nanomaterial 2 so that the support material 6 covers the entire end face of the nanomaterial 2;

[0066] Etch part of the support material 6 to the end face of the nanomaterial 2, and retain another part of the support material 6.

[0067] In some embodiments of the present invention, retaining another part of the support material 6 includes:

[0068] Use at least one nanocolumn or a larger range structure in the discrete nanocolumn structure as the frame of the metasurface optical element;

[0069] Retain the support material 6 on the end face of the frame.

[0070] In some embodiments of the present invention, it further includes:

[0071] Bond a glass wafer 5 to the top of the support material 6 to obtain the metasurface optical element.

[0072] As Figure 5As shown, first deposit the nanomaterial 2 on the end face of the substrate 1, and then deposit the support material 6 on the end face of the nanomaterial 2. Etch part of the support material 6 and part of the nanomaterial 2 to obtain a discrete nanocolumn structure and the support material 6 on the frame. Among the discrete nanocolumn structures of the metasurface optical element, at least one nanocolumn is selected as the frame of the metasurface optical element. The frame mainly plays a supporting role, and the support material 6 on the frame is retained. Next, deposit the protective material 4 in the gaps of the discrete nanocolumn structure and etch it. Finally, bond the glass wafer 5 to the top of the support material 6 to obtain the metasurface optical element.

[0073] In this embodiment, several of the foregoing embodiments are combined. By depositing the protective material 4, the nanocolumns are supported and not easily toppled, and the height of the protective material 4 is less than the height of the nanocolumns, increasing the relative refractive index of the metasurface optical element. In addition, there is a support material 6 on the frame, and the glass wafer 5 is bonded on the support material 6. The support material 6 avoids direct contact between the glass wafer 5 and the nanocolumns, and can reduce the degree of damage caused by the contact between the glass wafer 5 and the nanocolumns, while the glass wafer 5 can prevent damage to the nanocolumns caused by external collisions.

[0074] In the above embodiment Figure 5 the support material 6 can be used as a hard mask to assist in the formation of the nanocolumns, or the support material 6 on the support columns can be retained by lithographic etching first, and the rest of the support material 6 is removed, and then the above Figure 2 process flows in 3, 4 are carried out to obtain the nanocolumns, and finally the glass or other optically transparent material wafers are bonded.

[0075] In some embodiments of the present invention, before depositing the nanomaterial 2 on the end face of the substrate 1, it further includes:

[0076] Deposit a blocking material 7 on the end face of the substrate 1, and the blocking material 7 is used to terminate etching;

[0077] Deposit a second nanomaterial on the end face of the blocking material 7 to obtain a second nanomaterial 8 covering the entire end face of the blocking material 7;

[0078] Etch part of the second nanomaterial 8;

[0079] Deposit the first layer of nanomaterial 2 on the end face of the blocking material 7 exposed after etching.

[0080] In some embodiments of the present invention, the etching part of the second nanomaterial 8 includes:

[0081] Etch part of the second nanomaterial 8 to the blocking material 7 and retain the other part of the second nanomaterial 8;

[0082] Take the projection of the gap of the discrete nanocolumn structure on the end face of the substrate 1 as the first projection;

[0083] Take the projection of the remaining second nanomaterial 8 on the end face of the substrate 1 as the second projection;

[0084] The second projection is located within the first projection, and the area of the second projection is smaller than the area of the first projection.

[0085] As Figure 6 shown, first deposit a layer of blocking material 7 on the end face of the substrate 1. Since the material used as the blocking material 7 will not be etched, the etching will automatically stop when it reaches the blocking material 7. Then deposit the second nanomaterial 8 on the end face of the blocking material 7 to obtain a layer of the second nanomaterial 8. Then, according to the preset positions of the discrete nanocolumn structure, etch the second nanomaterial 8 so that the positions of the remaining multiple second nanomaterial 8 columns are located among the positions of the gaps of the discrete nanocolumn structure, and the widths of the multiple second nanomaterial 8 columns are smaller than the widths of the gaps of the discrete nanocolumn structure. Then deposit the first nanomaterial 2 on the exposed end face of the blocking material 7, with a thickness higher than that of the second nanomaterial 8 columns and having a flat surface. Coating a photoresist 3 on the obtained new substrate 1, performing structure direct writing, etching and subsequent steps to obtain a metasurface optical element.

[0086] In this embodiment, the nanocolumns are strengthened by constructing a layer of the second nanomaterial 8 and the first layer of nanomaterial 2. Since the bottom of the nanocolumn in contact with the substrate 1 is the first layer of nanomaterial 2 and the materials of the nanocolumn and the first layer of nanomaterial 2 are the same, compared with the case where the materials are different, the bonding force is greater, thereby enhancing the mechanical stability of the nanocolumns.

[0087] In summary, in the manufacturing method of the metasurface optical element according to the embodiment of the present application, by depositing a protective material 4 in the gap of the discrete nanocolumn structure to support the nanocolumns from falling down easily and enhance the mechanical stability of the nanocolumns; the height of the protective material 4 is less than the height of the nanocolumns to ensure the relative refractive index between the metasurface optical device and the working environment; bonding the glass wafer 5 to protect the nanocolumns from external damage; using the support material 6 to support the glass wafer 5 to prevent the glass wafer from contacting the nanocolumns and causing wear; constructing the first layer of the second nanomaterial 8 and the first layer of nanomaterial 2 to enhance the mechanical stability by increasing the bonding force between the nanocolumns and the substrate 1.

[0088] Although the alternative embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be interpreted to include the preferred embodiments as well as all changes and modifications falling within the scope of the present application.

[0089] The specific embodiments described above further elaborate on the purpose, technical solution, and beneficial effects of the present application. It should be understood that the above description is only the specific embodiments of the present application and is not used to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solution of the present application should be included within the protection scope of the present invention.

Claims

1. A manufacturing method of a metasurface optical element, characterized in that, The method includes: Depositing a nanomaterial on the end face of a substrate such that the nanomaterial covers the entire end face of the substrate; Etching a part of the nanomaterial to the end face of the substrate and retaining another part of the nanomaterial to obtain a discrete nanocolumn structure; Filling a protective material into the gaps of the discrete nanocolumn structure; Etching the protective material in the gaps of the discrete nanocolumn structure such that the height of the protective material in the gaps of the discrete nanocolumn structure is uniform and less than the height of the discrete nanocolumn structure to obtain the metasurface optical element; After depositing the nanomaterial on the end face of the substrate, the method further includes: Depositing a support material on the end face of the nanomaterial such that the support material covers the entire end face of the nanomaterial; Etching a part of the support material to the end face of the nanomaterial and retaining another part of the support material.

2. The manufacturing method of the metasurface optical element according to claim 1, characterized in that, After etching the protective material in the gaps of the discrete nanocolumn structure, it further includes: Bonding a glass wafer to the top of the discrete nanocolumn structure to protect the discrete nanocolumn structure.

3. The manufacturing method of the metasurface optical element according to claim 1, characterized in that, The retaining of another part of the support material includes: Using at least one nanocolumn in the discrete nanocolumn structure as a frame of the metasurface optical element; Retaining the support material above the end face of the frame.

4. The manufacturing method of the metasurface optical element according to claim 3, wherein It further includes: Bonding a glass wafer to the top of the support material to obtain the metasurface optical element.

5. The manufacturing method of the metasurface optical element according to claim 1, characterized in that, Before depositing the nanomaterial on the end face of the substrate, it further includes: Depositing a stop material on the end face of the substrate, where the stop material is used to terminate etching; Depositing a second nanomaterial on the end face of the stop material to obtain a second nanomaterial covering the entire end face of the stop material; Etching a part of the second nanomaterial; Depositing a first layer of nanomaterial on the end face of the stop material exposed after etching to obtain the substrate.

6. The manufacturing method of the metasurface optical element according to claim 5, characterized in that, The etching of a part of the second nanomaterial includes: Etching a part of the second nanomaterial to the stop material and retaining another part of the second nanomaterial; Taking the projection of the gaps of the discrete nanocolumn structure on the end face of the substrate as a first projection; Taking the projection of the retained second nanomaterial on the end face of the substrate as a second projection; The second projection is located within the first projection, and the area of the second projection is smaller than the area of the first projection.

7. The manufacturing method of the metasurface optical element according to claim 1, characterized in that, The materials used as the protective material include: silicon dioxide, plastic, titanium dioxide, silicon, germanium, silicon nitride, gallium nitride.

8. The manufacturing method of the metasurface optical element according to claim 1, characterized in that, The materials used as the nanomaterial include: silicon dioxide, crystalline silicon, amorphous silicon, germanium, titanium dioxide, silicon nitride, gallium nitride, optically transparent organic substances.

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