Preparation method of optical surface nanocone structure and nanocone structure

Abstract

The embodiment of the invention provides a preparation method of an optical surface nanocone structure and the nanocone structure, and relates to the technical field of micro-nano manufacturing. The method comprises the following steps: acquiring the required size of the nanocone; determining a target thin film material, a target thin film thickness and target etching process parameters according to the required size of the nanocone; evaporating a film on the surface of the target substrate according to the target film material and the target film thickness; wherein the surface of the target substrate is in any shape; and placing the target substrate plated with the thin film into an etching cavity, and performing plasma etching under target etching process parameters to obtain a target substrate of a nanocone structure formed on the surface. According to the method, the process of forming the nanoparticle mask by dehumidifying the thin film is integrated in plasma etching, so that efficient, large-area, uniform and size-controllable preparation of the optical surface nanocones with complex shapes is realized.

Description

Technical Field

[0001] The present application relates to the field of micro-nano manufacturing technology, and in particular to a preparation method of an optical surface nano-cone structure and a nano-cone structure. Background Art

[0002] Nanocone structures have broad application prospects in many fields, including optical windows, photovoltaics, display panels, and laser devices, due to their excellent performance in broadband and large acceptance angle anti-reflection. Fabricating nanocone structures on the surface of optical components can significantly reduce surface reflection and increase light transmittance, thereby improving the overall efficiency and performance of the device.

[0003] The self-mask plasma etching and mask-guided plasma etching in the related technology can directly etch the nanocone structure on the substrate surface. However, the current preparation methods of nanocones are mostly focused on optical components with simple geometric shapes such as flat windows and spherical fairings. There are limitations such as cumbersome preparation process and insufficient controllability of the characteristic size of nanocones. It is impossible to realize the controllable preparation of nanocones on surfaces with complex shapes such as microlens arrays and two-dimensional gratings. Summary of the invention

[0004] The main purpose of the embodiments of the present application is to provide a method for preparing an optical surface nanocone structure and a nanocone structure, which can realize the preparation of the nanocone structure for an optical element with a surface of any shape.

[0005] To achieve the above-mentioned purpose, a first aspect of an embodiment of the present application proposes a method for preparing an optical surface nanocone structure, the method comprising:

[0006] Obtaining a required size of a nanocone, wherein the required size of a nanocone comprises at least one of the following: a nanocone diameter and a nanocone height;

[0007] Determining target film material, target film thickness and target etching process parameters according to the required size of the nanocones;

[0008] Depositing a thin film on the surface of a target substrate according to the target thin film material and the target thin film thickness; wherein the surface of the target substrate is of any shape;

[0009] The target substrate coated with the thin film is placed in an etching chamber, and plasma etching is performed under the target etching process parameters to obtain a target substrate with a nanocone structure formed on the surface.

[0010] Optionally, placing the target substrate coated with the thin film into an etching chamber, performing plasma etching under the target etching process parameters to obtain the target substrate with a nanocone structure formed on the surface includes:

[0011] Placing the target substrate coated with the thin film into an etching chamber, bombarding the thin film with plasma under the target etching process parameters to dewet the thin film and form a nanoparticle mask in situ;

[0012] The target substrate is etched while the thin film is being dewetted, so that the target substrate forms a nanocone structure in situ on the nanoparticle mask, thereby obtaining a target substrate with a nanocone structure formed on the surface.

[0013] Optionally, etching the target substrate during the film dewetting process so that the target substrate forms a nanocone structure in situ on the nanoparticle mask to obtain a target substrate with a nanocone structure formed on the surface, comprises:

[0014] Performing a first-stage etching on the target substrate so as to form a nano-island structure on the target substrate in situ of the nano-particle mask;

[0015] The nano-island structure is subjected to a second stage of etching to form a nano-cone structure on the target substrate in situ of the nano-particle mask. If the nano-particle mask has completely disappeared, the second stage of etching is stopped to obtain a target substrate with a nano-cone structure formed on the surface.

[0016] Optionally, determining the target film material, target film thickness and target etching process parameters according to the required size of the nanocones includes:

[0017] Determining the target film material and the target film thickness according to the required size of the nanocones;

[0018] The target etching process parameters are determined according to the required size of the nanocones, the target film material and the target film thickness.

[0019] Optionally, the required size of the nanocones further includes the nanocone spacing and the nanocone density;

[0020] The step of determining the target film material and the target film thickness according to the required size of the nanocones includes:

[0021] Determining the aspect ratio according to the nanocone diameter and the nanocone height;

[0022] Mapping is performed according to the aspect ratio, the nanocone interval, the nanocone density, and a preset mapping relationship between the film material property and the nanocone size to obtain the target film material and the target film thickness.

[0023] Optionally, the target etching process parameters include target etching source power;

[0024] The step of determining the target etching process parameters according to the required size of the nanocones, the target film material and the target film thickness includes:

[0025] Using a source power mapping function, power mapping is performed on the required size of the nanocones, the target film material, and the target film thickness to obtain candidate etching source powers;

[0026] If the candidate etching source power is within a preset etching source power range, the candidate etching source power is determined as the target etching source power; wherein the etching source power range includes an etching source power lower limit value and an etching source power upper limit value;

[0027] If the candidate etching source power is less than the etching source power lower limit value, the etching source power lower limit value is determined as the target etching source power;

[0028] If the candidate etching source power is greater than the etching source power upper limit value, the etching source power upper limit value is determined as the target etching source power.

[0029] Optionally, the target etching process parameters also include a target bias power;

[0030] The step of determining the target etching process parameters according to the required size of the nanocones, the target film material and the target film thickness further includes:

[0031] Using a bias power mapping function, power mapping is performed on the required size of the nanocones, the target film material, and the target film thickness to obtain a candidate bias power;

[0032] If the candidate bias power is within a preset bias power interval, the candidate bias power is determined as the target bias power; wherein the bias power interval includes a bias power lower limit value and a bias power upper limit value;

[0033] If the candidate bias power is less than the bias power lower limit value, determining the bias power lower limit value as the target bias power;

[0034] If the candidate bias power is greater than the bias power upper limit value, the bias power upper limit value is determined as the target bias power.

[0035] Optionally, before evaporating a thin film on the surface of a target substrate according to the target thin film material and the target thin film thickness, the method further comprises:

[0036] Performing ultrasonic cleaning on the target substrate;

[0037] The cleaned target substrate is placed in a coating chamber.

[0038] Optionally, the material of the target substrate includes any one of the following: glass, gallium nitride, silicon carbide, and silicon.

[0039] To achieve the above-mentioned purpose, a second aspect of an embodiment of the present application proposes a nanocone structure, wherein the nanocone structure is prepared by the method for preparing an optical surface nanocone structure according to the first aspect.

[0040] The present application proposes a method for preparing an optical surface nanocone structure and a nanocone structure. The target film material, target film thickness and target etching process parameters are first determined based on the required size of the nanocones, and then coating and etching are performed. By integrating the process of thin film dewetting to form a nanoparticle mask into plasma etching, efficient, large-area uniform and size-controllable preparation of nanocones on optical surfaces of complex shapes can be achieved.

[0041] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is an optional flow chart of the method for preparing the optical surface nanocone structure provided in the embodiment of the present application;

[0043] Figure 2 This is a schematic diagram of the preparation process of a large-area nanocone structure on an optical surface of arbitrary shape provided in an embodiment of the present application;

[0044] Figure 3 This is the principle diagram of the thin film in-situ dehumidification assisted plasma etching process;

[0045] Figure 4 This is the result of preparing large-area uniform nanocones on the surface of a 2-inch glass wafer;

[0046] Figure 5 This is the result of preparing large-area uniform nanocones on the surface of the microcylindrical lens. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0048] It should be noted that, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first", "second", etc. in the specification, claims and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0050] Nanocone anti-reflection structures (also called nanocone array structures, hereinafter referred to as nanocone structures) have broad application prospects in many fields, including optical windows, photovoltaics, display panels, and laser equipment, due to their excellent performance in broadband and large acceptance angles. Preparing nanocone structures on the surface of optical components can significantly reduce surface reflections and improve light transmittance, thereby improving the overall efficiency and performance of the equipment. For example, in high-energy laser applications, nanocone structures can not only ensure high transmittance, but also improve the laser damage threshold of optical components, and enhance their durability and stability. With the rapid development of optical and electronic technologies, the application prospects of nanocone structures in high-performance optical devices are becoming increasingly broad. However, the current preparation methods of nanocones are mostly focused on optical components with simple geometric surfaces such as flat windows and spherical fairings. There are limitations such as cumbersome preparation processes and insufficient controllability of the characteristic dimensions of nanocones. It is impossible to achieve large-area uniform and controllable preparation of nanocones on surfaces with complex shapes such as microlens arrays and two-dimensional gratings.

[0051] At present, the mainstream nanocone preparation methods can be divided into two categories: additive manufacturing and subtractive manufacturing. Additive manufacturing methods such as nanoimprinting will introduce new materials on the surface of optical components, limiting the application of nanocone anti-reflection layers in extreme environments such as large temperature difference environments. Subtractive manufacturing methods such as plasma etching can directly etch nanocone structures on the surface of the substrate, avoiding the introduction of additional materials and material incompatibility. Therefore, plasma etching, as an efficient and reliable manufacturing method, is increasingly being used in the development and production of high-performance optical devices.

[0052] Typically, plasma etching methods use maskless and mask-guided etching to produce substrate-etched nanocones. Maskless plasma etching uses non-volatile etching byproducts as in-situ self-masks, which promotes the manufacture of randomly arranged nanocones. For example, the related art discloses a method for preparing random subwavelength broadband anti-reflection microstructures by self-masking, wherein a glass substrate is placed in a reaction chamber with a mixed reaction gas to implement a plasma etching process, and the nanoscale island-shaped polymer film generated on the surface of the glass substrate during the etching process is used as a mask for the etching process by controlling the etching parameters, so as to generate a randomly distributed refractive index gradient conical anti-reflection micro-nanostructure on the surface of the glass substrate. For example, the related art also discloses a method for preparing anti-reflection and super-hydrophilic subwavelength nanostructured glass surface by one-step self-mask reactive ion etching. A maskless glass substrate is placed in a reactive ion etching vacuum chamber, and after plasma treatment, a nanoscale fluorocarbon mask is automatically formed thereon as an etching mask, thereby forming a disordered subwavelength nanocone structure on the surface of the etched glass substrate. This one-step etching process makes this method for preparing nanocone structures simple and efficient.

[0053] Generally speaking, the mask-guided etching method involves two processing steps: nanoparticle mask preparation and plasma etching. Among them, the nanoparticle mask on the substrate is usually prepared by a metal film rapid heat treatment dehumidification method. Its size can be adjusted by changing the film thickness and heat treatment process parameters during the rapid heat treatment dehumidification process. It is a more efficient way to generate a nanoparticle mask on a large-area substrate. The nanometal particle mask prepared by the metal film dehumidification method can be used as an etching mask in the subsequent etching process. After etching, a subwavelength nanocone anti-reflection structure is generated on the surface of the substrate. The size and distribution state of the nanocone depends on the size and distribution of the nanoparticle mask. For example, the related art also discloses a method for preparing a subwavelength nanocone anti-reflection metasurface in two steps of metal film dehumidification and plasma etching process. A layer of platinum metal film is evaporated on the surface of a glass substrate, and a rapid heat treatment method is used to make the uniform platinum metal film melt first, and then condense into a plurality of nanometal droplets of similar size and uniform distribution under the action of surface tension, and finally cool and solidify to form a uniformly distributed nanoparticle mask. A glass substrate with a nanoparticle mask after rapid thermal treatment is placed in an etching chamber, and a uniformly distributed sub-wavelength nanocone structure is generated on the surface of the glass substrate after plasma etching.

[0054] In the above-mentioned self-mask plasma etching method, the formation of the self-mask is highly dependent on the etching formula, which limits the profile control of the nanocones during the manufacturing process, such as diameter, height and aspect ratio. The above-mentioned mask-guided plasma etching method involves multiple preparation processes, including metal film evaporation, rapid heat treatment to prepare nanoparticle masks, plasma etching, and removal of residual nanoparticle masks. Its preparation steps are relatively complicated, which limits the large-area and efficient preparation of nanocone anti-reflection structures. In addition, the common disadvantage of the above two technologies is that for optical elements with complex surface shapes, the above two methods are temporarily unable to achieve large-area uniform preparation of nanocone anti-reflection structures.

[0055] The present application aims to propose a preparation scheme for preparing a large-area nanocone structure on an optical surface of arbitrary shape (hereinafter referred to as a preparation method for an optical surface nanocone structure) to solve the problem of preparing a large-area uniform nanocone anti-reflection structure on the surface of a complex optical element. To this end, the present application proposes an efficient and controllable processing technology for preparing large-area nanocones by in-situ thin film dehumidification assisted plasma etching, and integrates the process of thin film dehumidification to form a nanoparticle mask into plasma etching to achieve efficient, large-area uniform, and size-controllable preparation of nanocones on optical surfaces of complex shapes. The method provided in the present application can also achieve flexible regulation of the diameter, height, and aspect ratio of the prepared nanocones by controlling the film thickness and etching process parameters, and is not limited by the radius of curvature and height difference of the substrate surface. It is applicable to a variety of thin film materials and can prepare large-area uniform nanocone anti-reflection structures on the surfaces of a variety of optical elements with complex shapes, such as microlens arrays, complex gratings, etc.

[0056] The embodiments of the present application provide a method for preparing an optical surface nanocone structure and a nanocone structure, which are specifically described through the following embodiments. First, the method for preparing the optical surface nanocone structure in the embodiments of the present application is described.

[0057] See also Figure 1 According to one embodiment of the present application, a method for preparing an optical surface nanocone structure includes:

[0058] Step 101, obtaining the required size of the nanocone, where the required size of the nanocone includes at least one of the following: the nanocone diameter and the nanocone height;

[0059] Step 102, determining the target film material, target film thickness and target etching process parameters according to the required size of the nanocones;

[0060] Step 103, evaporating a thin film on the surface of a target substrate according to a target thin film material and a target thin film thickness; wherein the surface of the target substrate is of any shape;

[0061] Step 104 , placing the target substrate coated with the thin film into an etching chamber, and performing plasma etching under target etching process parameters to obtain a nanocone structure formed on the surface.

[0062] The benefit of the embodiment of step 101 to step 104 is that the controllability of the size of the prepared nanocones is greatly improved by utilizing the good reproducibility and strong correlation between the etching mask and the structure obtained by etching. In addition, due to the advantage of the thin film dewetting process in the uniformity of preparing large-area nanoparticles, the uniformity of the nanocone array structure over a large area is greatly improved. Compared with the prior art, this embodiment also reduces the related steps of preparing the nanoparticle mask by rapid thermal treatment and removing the residual mask, greatly reducing the complexity of the process and improving the processing efficiency. It can be seen that this embodiment can realize the preparation of nanocone structures for optical elements with surfaces of arbitrary shapes, and the processing efficiency is high.

[0063] It should be noted that the preparation method provided in the present application can be applied to optical elements in the fields of imaging, display, laser processing, etc., such as lenses, mirrors, display glass panels, etc. The prepared nanocone structure is used as an anti-reflection layer on the surface of the element to improve the transmittance and reduce the reflectivity. It has anti-reflection capabilities over a wide band and a wide incident angle, and at the same time has a good laser-induced damage threshold.

[0064] In step 101 of some embodiments, the required size of the nanocone refers to the size of the nanocone structure that is expected to be prepared. The required size of the nanocone may include at least one of the following: nanocone diameter and nanocone height. The nanocone diameter may range from 50 nm to 200 nm, such as 125 nm. The nanocone height may range from 200 nm to 600 nm, such as 400 nm.

[0065] In step 102 of some embodiments, a preset size parameter mapping table may be searched according to the required size of the nanocones to obtain the target film material, target film thickness, and target etching process parameters.

[0066] The target thin film material refers to the material of the coating, which can be a metal with good thin film dewetting phenomenon such as gold, silver, copper or platinum. For example, the target thin film material is platinum.

[0067] The target film thickness refers to the thickness of the coating. The target coating thickness can range from 1nm to 20nm, for example, the target coating thickness is 10nm. The film deposition speed can also be set. The film deposition speed can range from to (0.2nm / s to 1nm / s), for example, the film deposition rate is 0.25nm / s.

[0068] The target etching process parameters refer to the parameters required for the etching process. The target etching process parameters may include the target etching gas, the target etching chamber pressure, the target etching source power, and the target bias power. The gases used for etching include, but are not limited to, argon, trifluoromethane, sulfur hexafluoride, oxygen and other gases. The gas flow rate of argon can be selected from 0sccm to 8sccm, the gas flow rate of trifluoromethane can be selected from 50sccm to 100sccm, the gas flow rate of sulfur hexafluoride can be selected from 50sccm to 100sccm, the gas flow rate of oxygen can be selected from 5sccm to 10sccm, the pressure of the etching chamber can be selected from 5mTorr to 10mTorr, the etching source power can be selected from 300W to 600W, the bias power can be selected from 30W to 70W, and the etching time can be selected from 2min to 30min (minutes). In one example, the target etching gas is composed of argon (8sccm), trifluoromethane (50sccm), and oxygen (5sccm), the target etching chamber pressure is 8mTorr, the target etching time is 15min, the target etching source power is 400W, and the target bias power is 50W. The selection of etching process parameters needs to be adjusted according to the material of the film, the thickness of the film, and the required size of the nanocone structure to be prepared. By changing the material, thickness, and etching process parameters of the film, the characteristic size and aspect ratio of the prepared nanocone can be adjusted.

[0069] In one embodiment, step 102 includes: determining a target film material and a target film thickness according to a required size of the nanocones; and determining a target etching process parameter according to the required size of the nanocones, the target film material and the target film thickness.

[0070] This embodiment first determines the target film material and target film thickness, and then determines the target etching process parameters, so that the film has a strong correlation with the etching process parameters, which facilitates the subsequent steps to simultaneously dewet the film during the etching process, further reducing the difficulty of preparation.

[0071] It should be noted that when determining the target film material, target film thickness and target etching process parameters, the following rules should be followed: ① Under the same diameter or height, reduce or increase the aspect ratio of the nanocone: the etching resistance of the film material should be weakened or enhanced accordingly, such as selecting materials with weaker / stronger etching resistance; ② Reduce or increase the diameter of the nanocone: the thickness of the film should be reduced or increased accordingly, or the etching source power and bias power should be increased or decreased, and the etching gas flow rate should be increased or decreased (but it needs to be kept within the range). ③ Different substrate materials: Select the reactive etching gas of the corresponding material, such as silicon-based materials (silicon, silicon dioxide, silicon carbide, etc.) can select fluorine-based etching gas (such as trifluoromethane, sulfur hexafluoride, etc.).

[0072] In addition to the nanocone diameter and the nanocone height, the required nanocone size may also include the nanocone spacing and the nanocone density. In one embodiment, the step of determining the target film material and the target film thickness according to the required nanocone size may include: determining the height-to-diameter ratio according to the nanocone diameter and the nanocone height; and mapping the height-to-diameter ratio, the nanocone spacing, the nanocone density, and the preset film material properties and the nanocone size to obtain the target film material and the target film thickness.

[0073] According to the different required sizes of nanocones, it is necessary to select the corresponding appropriate film material and thickness. The selection of film material and thickness mainly determines the nanocone spacing, nanocone density and the maximum achievable aspect ratio. For different film materials, the etching resistance and film dewetting phenomena are significantly different. The properties of the film material determine the size, distribution state and etching ratio of the nanoparticles formed by film dewetting, and indirectly determine the characteristic parameters such as the prepared nanocone spacing, nanocone density and the maximum aspect ratio of the nanocones.

[0074] The target etching process parameters include the target etching source power. In one embodiment, the step of determining the target etching process parameters according to the required nanocone size, target film material and target film thickness may include: using a source power mapping function to perform power mapping on the required nanocone size, target film material and target film thickness to obtain a candidate etching source power; if the candidate etching source power is within a preset etching source power interval, the candidate etching source power is determined as the target etching source power; wherein the etching source power interval includes an etching source power lower limit value and an etching source power upper limit value; if the candidate etching source power is less than the etching source power lower limit value, the etching source power lower limit value is determined as the target etching source power; if the candidate etching source power is greater than the etching source power upper limit value, the etching source power upper limit value is determined as the target etching source power.

[0075] When performing the above power mapping, the target film material can be first converted into a material coefficient, and then the source power mapping function can be used to perform power mapping on the required nanocone size, material coefficient and target film thickness to obtain the candidate etching source power. A mapping relationship table can also be used to directly look up the table according to the required nanocone size, target film material and target film thickness to obtain the candidate etching source power. In this way, the process of determining the power using the source power mapping function is relatively simple and flexible.

[0076] Considering that the etching source power of the etching equipment is limited in the actual scenario, that is, the etching equipment has an etching source power range. In this scenario, if the candidate etching source power is in the preset etching source power range, the candidate etching source power is determined as the target etching source power; if the candidate etching source power is less than the lower limit of the etching source power, the lower limit of the etching source power is determined as the target etching source power; if the candidate etching source power is greater than the upper limit of the etching source power, the upper limit of the etching source power is determined as the target etching source power. In this way, while retaining the correlation between the target etching source power and the thin film as much as possible, it takes into account practicality and has high universality.

[0077] The target etching process parameters also include a target bias power. In one embodiment, the step of determining the target etching process parameters according to the required nanocone size, target film material and target film thickness may also include: using a bias power mapping function to perform power mapping on the required nanocone size, target film material and target film thickness to obtain a candidate bias power; if the candidate bias power is within a preset bias power interval, the candidate bias power is determined as the target bias power; wherein the bias power interval includes a bias power lower limit and a bias power upper limit; if the candidate bias power is less than the bias power lower limit, the bias power lower limit is determined as the target bias power; if the candidate bias power is greater than the bias power upper limit, the bias power upper limit is determined as the target bias power. This embodiment is similar to the above-mentioned embodiment of determining the target etching source power, and will not be repeated here. This embodiment also takes into account practicality while retaining the correlation between the target bias power and the film as much as possible, and has high universality.

[0078] It should be noted that different complex shapes of optical surfaces and substrate materials will also affect the target etching process parameters. Therefore, in one embodiment, the target etching process parameters are determined according to the required size of the nanocones, the target film material, the target film thickness, the shape of the optical surface and the substrate material. The specific determination method can be based on a formula or a mapping table. This embodiment can further improve the accuracy of the target etching process parameters.

[0079] Before step 103, the method for preparing the optical surface nanocone structure may further include: ultrasonically cleaning the target substrate; and placing the cleaned target substrate in a coating chamber.

[0080] The target substrate material may include any of the following: glass, gallium nitride, silicon carbide, silicon. The cleaning fluids in the ultrasonic cleaning process before coating include acetone, isopropyl alcohol, and distilled water. Ultrasonic cleaning is carried out in sequence, and the cleaning time of each cleaning fluid is ≥10 minutes. Finally, it is blown dry with clean compressed air for the next coating step. The purpose of the cleaning process is to prevent contaminants on the surface of the substrate from affecting the uniformity of the surface coating, and to prevent contaminants from affecting the adhesion between the film and the substrate, thereby causing the film to fall off easily.

[0081] In step 103 of some embodiments, a thin film is evaporated on the surface of a target substrate according to the target film material and the target film thickness. The surface of the target substrate is of any shape. For example, the surface of a flat window, a spherical fairing, etc. is a simple geometric shape (such as a plane, a sphere, etc.), and the surface of a microlens array, a micro-trapezoid array, a micro-groove, a two-dimensional grating, etc. is a complex geometric shape (the external contour or surface structure is very complex, and may include various irregular curves, bumps, boundaries and textures, or a surface with variable curvature).

[0082] The equipment that can be used for coating includes but is not limited to electron beam evaporation equipment, vacuum sputtering equipment, magnetron sputtering coating equipment and other coating equipment. The above coating chamber is set in the coating equipment. If the limitations of the coating equipment and etching equipment platform are ignored, the preparation method provided by this application can realize the preparation of large-area uniform nanocone structure on a larger area of ​​complex-shaped optical surface.

[0083] In step 104 of some embodiments, the target substrate coated with the thin film is placed in an etching chamber, and plasma etching is performed under target etching process parameters to obtain a nanocone structure formed on the surface. The preparation scheme of this embodiment using in-situ dewetting of thin films to assist plasma etching is a key means to achieve the preparation of large-area uniform nanocone anti-reflection structures on complex-shaped optical surfaces. By integrating the thin film dewetting process into the plasma etching step, and selecting and optimizing the thin film material, thickness and etching process parameters, the uniform evolution and controllable adjustment of the thin film dewetting process on large-area, complex-shaped surfaces, as well as the large-area uniform and controllable preparation of the characteristic dimensions of the nanocone structure are achieved, thereby achieving the purpose of preparing large-area uniform nanocone structures on complex-shaped optical surfaces.

[0084] It should be noted that the target substrate and the film are controlled in temperature by liquid helium back cooling, so that the temperature of the target substrate and the film are maintained within a predetermined temperature range. The etching equipment that can be used in the plasma etching process includes but is not limited to reactive ion etching equipment, inductively coupled plasma etching equipment, etc.

[0085] In one embodiment, the step of placing the target substrate coated with a thin film into an etching chamber and performing plasma etching under target etching process parameters to obtain a nanocone structure formed on the surface may include: placing the target substrate coated with a thin film into an etching chamber, bombarding the thin film with plasma under target etching process parameters to dewet the thin film and form a nanoparticle mask in situ; etching the target substrate while the thin film is being dewetted so that the target substrate forms a nanocone structure in situ of the nanoparticle mask, thereby obtaining a nanocone structure formed on the surface.

[0086] Specifically, during the plasma etching process, the thin film is exposed to the continuous bombardment of high-energy plasma, and the thin film is dewetted, thereby forming a nanoparticle mask in situ. Under the continuous etching action of the plasma, the substrate simultaneously evolves and generates a nanocone structure in situ of the nanoparticle mask, wherein the evolution and formation of the nanocone structure are carried out synchronously with the process of dewetting the thin film to form the nanoparticle mask.

[0087] Considering that the dewetting process and the etching process occur simultaneously, in one embodiment, the step of etching the target substrate during the film dewetting process so that the target substrate forms a nanocone structure in situ on the nanoparticle mask, and obtaining the nanocone structure formed on the surface may include:

[0088] Performing a first-stage etching on the target substrate so as to form a nano-island structure on the target substrate in situ of the nano-particle mask;

[0089] The nano-island structure is subjected to a second stage of etching to form a nano-cone structure in situ on the target substrate of the nano-particle mask. If the nano-particle mask has completely disappeared, the second stage of etching is stopped to obtain a nano-cone structure formed on the surface.

[0090] In the above embodiment, an etching time threshold can be pre-set, and timing is started after the target substrate is placed in the etching chamber. If the accumulated etching time is greater than the etching time threshold, etching is stopped, and finally a nanocone structure is formed on the surface.

[0091] Reference Figure 2 , the preparation method may include the following steps:

[0092] (1) According to the required size of the nanocone, including the nanocone diameter of 125 nm and the nanocone height of 400 nm, the target film material is determined to be platinum, the target film thickness is 10 nm, and the target etching process parameters include the etching gas composition of argon (8 sccm), trifluoromethane (50 sccm), oxygen (5 sccm), the etching chamber pressure is 8 mTorr, the target etching source power is 400 W, the target bias power is 50 W, and the etching time is 15 min.

[0093] (2) The blank glass substrate 100 is ultrasonically cleaned. For example, a fused silica glass substrate material of model JGS1 is selected as the glass substrate 100. The film deposition rate.

[0094] (3) After cleaning, place it in a chamber such as electron beam evaporation or magnetron sputtering. According to the platinum, 10nm and The coating is performed to obtain a glass substrate 200 coated with a uniform thin film.

[0095] (4) The glass substrate 200 coated with a uniform thin film is placed in a plasma etching chamber for etching, and after 15 minutes, a glass substrate 300 with a large area of ​​uniform nanocones generated on the surface is obtained. The above target etching process parameters are used during the etching process.

[0096] Figure 3 The figure shows the process of thin film in-situ dehumidification assisted plasma etching of a glass substrate coated with a thin film in an etching chamber. Figure 3 As shown, in the early stage of the etching process, the glass substrate coated with a thin film on the surface has the shape of the thin film 400 and the glass substrate 500 on the surface intact. With the continuous bombardment of high-energy plasma, the thin film gradually breaks, forming a thin film 600 in the early stage of dewetting, and the holes on the thin film 600 cause the glass substrate in the hole area to be exposed to the plasma, and a slightly etched glass substrate 700 is formed under the action of plasma. At this time, the structure of the surface of the glass substrate presents the form of nanopores. As the plasma etching process continues, the holes existing on the surface of the thin film 600 in the early stage of dewetting gradually expand and merge, and finally form a nanoparticle mask 800 after the film is in-situ dewetted, and the slightly etched glass substrate 700 is subjected to the action of plasma etching to obtain a glass substrate 900 with nano islands formed on the surface. Under the continued action of plasma, the formed nanoparticle mask 800 will gradually be dissipated, the size will be reduced, and finally disappear completely. At the same time, the glass substrate 900 with nano islands on the surface will further evolve to form a glass substrate 1000 with nano cones on the surface. With further etching, due to the load effect in plasma etching, the glass substrate 1000 with surface nanocones is over-etched, resulting in the formation of an over-etched surface nano-papillary structure glass substrate 1100. By controlling the time of plasma etching, the evolution of the surface nanostructure of the glass substrate can be stopped at the time point when the nanocone glass substrate 1100 is formed, thereby achieving the processing goal of preparing a large-area uniform nanocone structure on the surface of the glass substrate.

[0097] Figure 4 This is the result of preparing large-area uniform nanocones on the surface of a 2-inch glass wafer. Figure 4As shown, the upper left is a physical picture of a large-area uniform nanocone structure prepared on the surface of a 2-inch glass wafer, and the lower left, upper right and lower right are electron microscope pictures of different areas. Figure 5 This is the result of preparing large-area uniform nanocones on the surface of micro-column lenses. Figure 5 As shown, the top is the three-dimensional outline of the micro-column lens, and the lower left and lower right are electron microscope images of uniform nano-cone structures prepared on the micro-column lens. It can be seen that the preparation method provided by the present application can achieve the processing goal of preparing a large-area uniform nano-cone structure on a surface of any shape.

[0098] The embodiment of the present application further discloses a nanocone structure, which is prepared by the above-mentioned method for preparing the optical surface nanocone structure.

[0099] The embodiments described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0100] Those skilled in the art will appreciate that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0101] Those skilled in the art will appreciate that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices may be implemented as software, firmware, hardware, or a suitable combination thereof.

[0102] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0103] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0104] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A method for preparing an optical surface nanocone structure, characterized in that: The method comprises: Obtaining a required size of a nanocone, wherein the required size of a nanocone comprises at least one of the following: a nanocone diameter and a nanocone height; Determining target film material, target film thickness and target etching process parameters according to the required size of the nanocones; Depositing a thin film on the surface of a target substrate according to the target thin film material and the target thin film thickness; wherein the surface of the target substrate is of any shape; The target substrate coated with the thin film is placed in an etching chamber, and plasma etching is performed under the target etching process parameters to obtain a target substrate with a nanocone structure formed on the surface.

2. The method according to claim 1, characterized in that The target substrate coated with the thin film is placed in an etching chamber, and plasma etching is performed under the target etching process parameters to obtain a target substrate with a nanocone structure formed on the surface, including: Placing the target substrate coated with the thin film into an etching chamber, bombarding the thin film with plasma under the target etching process parameters to dewet the thin film and form a nanoparticle mask in situ; The target substrate is etched while the thin film is being dewetted, so that the target substrate forms a nanocone structure in situ on the nanoparticle mask, thereby obtaining a target substrate with a nanocone structure formed on the surface.

3. The method according to claim 2, characterized in that The target substrate is etched during the film dewetting process so that the target substrate forms a nanocone structure in situ on the nanoparticle mask to obtain a target substrate with a nanocone structure formed on the surface, comprising: Performing a first-stage etching on the target substrate so that the target substrate forms a nano-island structure in situ of the nano-particle mask; The nano-island structure is subjected to a second stage of etching to form a nano-cone structure on the target substrate in situ of the nano-particle mask. If the nano-particle mask has completely disappeared, the second stage of etching is stopped to obtain a target substrate with a nano-cone structure formed on the surface.

4. The method according to any one of claims 1 to 3, characterized in that: Determining the target film material, target film thickness and target etching process parameters according to the required size of the nanocones includes: Determining the target film material and the target film thickness according to the required size of the nanocones; The target etching process parameters are determined according to the required size of the nanocones, the target film material and the target film thickness.

5. The method according to claim 4, characterized in that The required size of nanocones also includes nanocone spacing and nanocone density; The step of determining the target film material and the target film thickness according to the required size of the nanocones includes: Determining the aspect ratio according to the nanocone diameter and the nanocone height; Mapping is performed according to the aspect ratio, the nanocone interval, the nanocone density, and a preset mapping relationship between the film material property and the nanocone size to obtain the target film material and the target film thickness.

6. The method according to claim 4, characterized in that The target etching process parameters include target etching source power; The step of determining the target etching process parameters according to the required size of the nanocones, the target film material and the target film thickness includes: Using a source power mapping function, power mapping is performed on the required size of the nanocones, the target film material, and the target film thickness to obtain a candidate etching source power; If the candidate etching source power is within a preset etching source power range, the candidate etching source power is determined as the target etching source power; wherein the etching source power range includes an etching source power lower limit value and an etching source power upper limit value; If the candidate etching source power is less than the etching source power lower limit value, the etching source power lower limit value is determined as the target etching source power; If the candidate etching source power is greater than the etching source power upper limit value, the etching source power upper limit value is determined as the target etching source power.

7. The method according to claim 6, characterized in that The target etching process parameters also include a target bias power; The step of determining the target etching process parameters according to the required size of the nanocones, the target film material and the target film thickness further includes: Using a bias power mapping function, power mapping is performed on the required size of the nanocones, the target film material, and the target film thickness to obtain a candidate bias power; If the candidate bias power is within a preset bias power interval, the candidate bias power is determined as the target bias power; wherein the bias power interval includes a bias power lower limit value and a bias power upper limit value; If the candidate bias power is less than the bias power lower limit value, determining the bias power lower limit value as the target bias power; If the candidate bias power is greater than the bias power upper limit value, the bias power upper limit value is determined as the target bias power.

8. The method according to any one of claims 1 to 3, characterized in that: Before evaporating a thin film on the surface of a target substrate according to the target thin film material and the target thin film thickness, the method further comprises: Performing ultrasonic cleaning on the target substrate; The cleaned target substrate is placed in a coating chamber.

9. The method according to any one of claims 1 to 3, characterized in that: The material of the target substrate includes any one of the following: glass, gallium nitride, silicon carbide, and silicon.

10. A nanocone structure, characterized in that: The nanocone structure is prepared by the method for preparing an optical surface nanocone structure according to any one of claims 1 to 9.

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