A method for preparing a double-sided nanoimprint structure

Abstract

The present invention provides a method for preparing a double-sided nanoimprint structure, wherein the method comprises: forming a first photoresist coating, and patterning the first photoresist coating corresponding to the substrate shielding portion of the first photoresist coating; etching the first substrate A surface to form a groove structure, and removing the substrate shielding portion; substrate bonding the first substrate and the second substrate to form a sealed cavity; forming a first UV protective layer, and performing a structured treatment on the second substrate B surface to form a first nanostructure layer; removing the first UV protective layer, forming a second UV protective layer on the second substrate B surface, and performing a structured treatment on the first substrate B surface to form a second nanostructure layer located on the first substrate B surface, wherein the second nanostructure layer includes a plurality of second structure circular holes arranged in an array; removing the second UV protective layer to obtain a double-sided nanoimprint structure. The present invention at least improves the preparation efficiency and consistency.

Description

Technical Field

[0001] The invention relates to semiconductor technology, and in particular to a method for preparing a double-sided nanoimprint structure. Background Art

[0002] Double-sided nanoimprinting technology can simultaneously perform high-precision nanostructure patterning on both sides of the material. It has broad application prospects in optoelectronics, optics, biomedicine, microelectronics, display technology, energy storage and nanofluids. The difficulty of double-sided nanoimprinting is how to protect the other side from contamination or damage while processing one side. In theory, the first side can be processed first, followed by standard cleaning, and then the second side can be processed. However, there are problems that the cleaning fluid will corrode the nanostructure and the nanoimprinting process will destroy the unprotected nanostructure on the first side. Therefore, back protection is a key technology that must be solved for double-sided nanoimprinting.

[0003] In the field of MEMS and NEMS, traditional back side protection solutions include: temporary bonding of photoresist and microcrystalline wax as an intermediate layer. The preparation of photoresist samples is complex and has poor thermal conductivity, while microcrystalline wax is not resistant to high temperatures and cannot be removed cleanly. Blue film is directly applied to the back of the sample. The cost of blue film is relatively cheap, but the viscosity will change with temperature and it is easy to leave residual adhesive.

[0004] Therefore, in order to ensure the quality of the nanostructure, it is necessary to ensure that the process surface is not contaminated during the processing. Based on this application requirement, this patent proposes a double-sided nanoimprint structure preparation method using UV film. Summary of the invention

[0005] Based on the above problems, the present invention is proposed to provide a method for preparing a double-sided nanoimprint structure that overcomes the above problems or at least partially solves the above problems.

[0006] According to one aspect of the present invention, there is provided a method for preparing a double-sided nanoimprint structure, comprising the following steps:

[0007] Forming a first photoresist coating on the first substrate A surface of the first substrate, and performing patterning based on the first photoresist coating to obtain substrate shielding portions corresponding to the first photoresist coating and located on both sides of the first substrate A surface;

[0008] Etching the first substrate surface A of the first substrate to form a groove structure located in the middle of the first substrate surface A, and removing the substrate shielding portion;

[0009] Bonding the first substrate and the second substrate in a manner that the first substrate A surface of the first substrate is attached to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity;

[0010] forming a first UV protective layer on the first substrate surface B of the first substrate, and performing a structural treatment on the second substrate surface B of the second substrate to form a first nanostructure layer located on the second substrate surface B, wherein the first nanostructure layer includes a plurality of first structure circular holes arranged in an array;

[0011] The first UV protective layer is removed, a second UV protective layer is formed on the second substrate B surface of the second substrate, and the first substrate B surface of the first substrate is structured to form a second nanostructure layer located on the first substrate B surface, wherein the second nanostructure layer includes a plurality of second structure circular holes arranged in an array.

[0012] Optionally, in the method according to the present invention, etching the first substrate surface A of the first substrate comprises:

[0013] wet-etching the first substrate surface A of the first substrate; or,

[0014] The first substrate A surface of the first substrate is dry-etched.

[0015] Optionally, in the method according to the present invention, substrate bonding is performed on the first substrate and the second substrate in a manner that the first substrate A surface of the first substrate is attached to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity, comprising:

[0016] In a vacuum environment, the first substrate and the second substrate are bonded by a thermal compression bonding process in a manner that the first substrate A surface of the first substrate is attached to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity.

[0017] Optionally, in the method according to the present invention, performing a structuring treatment on the second substrate surface B of the second substrate to form a first nanostructure layer located on the second substrate surface B includes:

[0018] forming a first nano-mask on the second substrate B surface of the second substrate by using nano-imprint technology;

[0019] The surface B of the second substrate is dry-etched based on the first nanomask, and the first nanomask is removed to form a first nanostructure layer located on the surface B of the second substrate.

[0020] Optionally, in the method according to the present invention, removing the first UV protective layer and forming a second UV protective layer on the second substrate B surface of the second substrate comprises:

[0021] irradiating the first UV protective layer with ultraviolet light for a preset irradiation time to perform a photolysis process corresponding to the first UV protective layer;

[0022] After the photolysis process of the first UV protective layer is completed, the first UV protective layer is removed, and a second UV protective layer is formed on the second substrate B surface of the second substrate.

[0023] Optionally, in the method according to the present invention, the first UV protective layer is removed, and then the method further comprises:

[0024] When the removal of the first UV protective layer is completed, the acquisition unit is controlled to acquire an image of the surface B of the first substrate, and image recognition is performed on the acquired substrate image;

[0025] When it is determined based on the recognition result that noise regions corresponding to different residual substances exist in the substrate acquisition image, the number of regions corresponding to each noise region and the region proportion corresponding to each noise region are obtained;

[0026] The area quantity and area proportion are respectively multiplied by the retrieved normalized value of quantity and normalized value of proportion to obtain an initial quantity evaluation value and an initial area evaluation value;

[0027] The initial quantity evaluation value and the initial area evaluation value are respectively multiplied by the retrieved quantity weight value and the area weight value to obtain the current quantity evaluation value of the corresponding quantity dimension and the current area evaluation value of the corresponding area dimension;

[0028] Based on the sum of the current quantity evaluation value and the current area evaluation value, obtaining a residual evaluation value corresponding to the first UV protective layer;

[0029] The residue evaluation value is compared with a preset evaluation threshold, and when the residue evaluation value is greater than or equal to the preset evaluation threshold, the surface B of the first substrate is determined to be unqualified.

[0030] Optionally, in the method according to the present invention, the method further comprises:

[0031] Obtaining an actual evaluation value inputted by the preparation process end based on the residual evaluation value, and comparing the residual evaluation value with the actual evaluation value by score;

[0032] When the actual evaluation value is greater than the residual evaluation value, increasing training is performed on the quantity weight value and the area weight value;

[0033] When the actual evaluation value is greater than the residual evaluation value, the quantity weight value and the area weight value are reduced by training;

[0034] The number weight value and area weight value after training are obtained through the following formula:

[0035] in, is the quantity weight value Increase the number of training sessions. is the quantity weight value The training constant value of is the quantity weight value Reduce the number of training sessions. is the quantity weight value after training, is the area weight value Increase the number of training sessions. is the area weight value The training constant value of is the area weight value Reduce the number of training sessions. is the area weight value after training.

[0036] Optionally, in the method according to the present invention, the method further comprises:

[0037] When the residual evaluation value is less than the preset evaluation threshold, coordinate processing is performed on the substrate acquisition image to obtain the image coordinate points constituting the substrate acquisition image;

[0038] Determine the image coordinate points constituting each noise area as a noise coordinate group, and determine the image coordinate points corresponding to the X-axis maximum value, the X-axis minimum value, the Y-axis maximum value, and the Y-axis minimum value as the X-axis maximum coordinate point, the X-axis minimum coordinate point, the Y-axis maximum coordinate point, and the Y-axis minimum coordinate point based on the noise coordinate group;

[0039] A first X-axis extension line and a second X-axis extension line are established along the X-axis maximum coordinate point and the X-axis minimum coordinate point as starting points, respectively, and the first Y-axis extension line and the second Y-axis extension line are established along the Y-axis maximum coordinate point and the Y-axis minimum coordinate point as starting points, respectively, and the X-axis of the corresponding image coordinate system.

[0040] Generate a noise frame surrounding each noise area based on the first X-axis extension line, the second X-axis extension line, the first Y-axis extension line, and the second Y-axis extension line, and obtain a frame center point corresponding to the noise frame;

[0041] Taking the center point of the frame as the irradiation center, ultraviolet rays are used to continuously irradiate the B surface of the first substrate for a preset irradiation time, and after the irradiation is completed, a cleaning operation is performed on the B surface of the first substrate.

[0042] Optionally, in the method according to the present invention, performing a structuring treatment on the first substrate surface B of the first substrate to form a second nanostructure layer located on the first substrate surface B includes:

[0043] forming a second nanomask on the first substrate B surface of the first substrate by using nanoimprint technology;

[0044] The surface B of the first substrate is dry-etched based on the second nanomask, and the second nanomask is removed to form a second nanostructure layer located on the surface B of the first substrate.

[0045] According to another aspect of the present invention, there is provided a double-sided nanoimprint structure prepared based on the above-mentioned method for preparing the double-sided nanoimprint structure, comprising:

[0046] a first substrate and a second substrate;

[0047] Among them, the first substrate B surface of the first substrate and the second substrate B surface of the second substrate are respectively formed with a second nanostructure layer including a plurality of second structure circular holes arranged in an array and a first nanostructure layer including a plurality of first structure circular holes arranged in an array, the first substrate A surface of the first substrate is formed with a groove structure, and the first substrate A surface of the first substrate is adhered to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity.

[0048] According to the scheme of the present invention, the present invention successfully prepares an imprinted structure with a double-sided nanostructure by sequentially performing patterning of a photoresist coating, etching, substrate bonding, formation and removal of a UV protective layer, and application of nanoimprint technology on a substrate. The key lies in the application and removal of the UV protective layer, which can effectively improve the surface quality of the nanostructure. Specifically, the double-sided nanostructure layer obtained based on the present invention can effectively enhance the optical properties of the material, reduce the reflection loss of light, and improve the transmittance of light, and is suitable for optical devices, sensors and other fields. In addition, the present invention can further ensure the high precision and large-area uniformity of the nanostructure through precise etching and nanoimprinting processes, thereby improving the preparation efficiency and consistency. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A flow chart showing a method for preparing a double-sided nanoimprint structure according to an embodiment of the present invention is shown;

[0050] Figure 2 A schematic diagram showing a substrate shielding portion formed on the first substrate A surface in this embodiment;

[0051] Figure 3 A schematic diagram showing a groove structure formed on the first substrate A surface in this embodiment;

[0052] Figure 4 A schematic diagram of substrate bonding between a first substrate and a second substrate in this embodiment is shown;

[0053] Figure 5 A schematic diagram showing the formation of a first UV protective layer on the first substrate B surface in this embodiment is shown;

[0054] Figure 6 A schematic diagram showing forming a first nano-mask on the surface B of the second substrate in this embodiment is shown;

[0055] Figure 7 A schematic diagram showing the formation of a first nanostructure layer on the second substrate B surface in this embodiment;

[0056] Figure 8 A schematic diagram of irradiating the first UV protective layer with ultraviolet rays in this embodiment is shown;

[0057] Fig. 9 A schematic diagram showing the formation of a second UV protective layer on the second substrate B surface in this embodiment;

[0058] Fig.10 A schematic diagram showing the formation of a second nanostructure layer on the first substrate B surface in this embodiment;

[0059] Fig.11 A schematic diagram showing the deposition of SiO2 thin film based on PECVD using a UV protective layer when processing a sapphire double-sided nanoimprint structure in this embodiment;

[0060] Fig.12 The actual image of the sapphire double-sided nanoimprint structure processed in this embodiment is shown;

[0061] Fig.13 The front view SEM result image of the nanostructure layer of the sapphire double-sided nanoimprint structure processed in this embodiment is shown;

[0062] Fig.14 The cross-sectional SEM result image of the nanostructure layer of the sapphire double-sided nanoimprint structure processed in this embodiment is shown;

[0063] Fig.15 The cross-sectional oblique SEM result image of the nanostructure layer of the sapphire double-sided nanoimprint structure processed in this embodiment is shown. DETAILED DESCRIPTION

[0064] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0065] In order to solve the problems existing in the above background technology, an embodiment of the present invention provides a method for preparing a double-sided nanoimprint structure. Figure 1 The flowchart of the method for preparing the double-sided nanoimprint structure proposed in this embodiment is shown as follows: Figure 1 As shown, the method starts at step S101, and in step S101, the following contents are included:

[0066] A first photoresist coating is formed on the first substrate A surface of the first substrate, and patterning is performed based on the first photoresist coating to obtain substrate shielding portions corresponding to the first photoresist coating and located on both sides of the first substrate A surface.

[0067] For example, Figure 1 As shown, in the present embodiment, the above process is mainly intended to provide a corresponding etching mask for the subsequent process, that is, by performing photoresist-based spin coating on the first substrate A surface of the first substrate, a first photoresist coating located on the first substrate A surface can be formed, and by further performing corresponding patterning treatment on the first photoresist coating (that is, performing exposure, display and other operations), a substrate shielding portion corresponding to the first photoresist coating located on both sides of the first substrate A surface can be obtained.

[0068] It should be noted that, in this embodiment, different processes may be used to form corresponding substrate shielding portions based on different materials of the corresponding first substrate.

[0069] For example, when the first substrate is fused quartz or borosilicate glass, in one method, photoresist and metal Cr can be used for dry etching to form the corresponding substrate shielding portion. The specific process includes: firstly, photoresist is spread (photoresist model AZ6130, 3000 rpm spin coating photoresist, front baking plate temperature is 100°C for 60s, exposure dose is 100mj / cm^2, developer ratio AZ400K and deionized water volume ratio is 1:6, development time is 38~42s, plasma is used to remove residual glue), electron beam evaporates Cr film (vacuum degree <10^-6Torr, thickness of metal Cr is 30nm), organic solvent ultrasonic stripping (placed in acrylic acid) Pre-ultrasonication in ketone for 3 minutes, then ultrasonication in anhydrous ethanol for 3 minutes, repeating anhydrous ethanol for 2 to 3 times, then rinsing with deionized water and drying on a hot plate); in another method, photoresist can be used for wet etching to form the corresponding substrate shielding portion, and the corresponding specific process includes: photoresist model AZ4620, 1000 rpm spin coating photoresist, front hot plate temperature 100°C for 120s, exposure dose 400~450mj / cm2, developer ratio AZ400K and deionized water volume ratio of 1:2, development time 80~90s, plasma to remove residual glue, and post-baking plate temperature 120°C for 10min;

[0070] For example, if the material is silicon carbide, metal Ni can be used as a mask. The specific preparation process includes: first, photoresist is spread (photoresist model AZ6130, 3000 rpm spin coating photoresist, the temperature of the front hot plate is 100℃ for 60s, the exposure dose is 100mj / cm^2, the volume ratio of the developer AZ400K and deionized water is 1:6, the development time is 38~42s, and the residual glue is removed by plasma), electron beam evaporation of Ni film (vacuum degree <10^-6Torr, metal Ni, thickness 30nm), organic solvent ultrasonic stripping (pre-ultrasonication in acetone for 3min, pre-ultrasonication in anhydrous ethanol for 3min, repeat anhydrous ethanol 2~3 times, rinse with deionized water, and dry on a hot plate);

[0071] For example, if the corresponding material is sapphire, silicon oxide can be used as a dry and wet etching mask. The specific preparation process is: first use PECVD to deposit a 300nm silicon oxide film (process parameters SiH4 / 130sccm, O2 / 13sccm, Ar / 32.5sccm, temperature 130℃, pressure 0.8Pa, time 1000s), photoresist (photoresist model AZ6130, 3000 rpm spin coating photoresist, front baking plate temperature 100℃ for 60s, exposure dose 100mj / cm^2, developer ratio AZ400K and deionized water volume ratio of 1:6, development time 38~42s, plasma to remove residual glue, rear baking plate temperature 120℃ for 10min), RIE etching (etching gas CHF3, flow rate 30sccm, reaction chamber pressure 1.3pa, ion source power 90w, etching rate 23nm / min, etching time 18min).

[0072] In step S102, the following contents are included:

[0073] The first substrate A surface of the first substrate is etched to form a groove structure located in the middle of the first substrate A surface, and the substrate shielding portion is removed.

[0074] like Figure 2 as well as Figure 3 As shown, after the corresponding substrate shielding portion is formed, the substrate shielding portion can be used as an etching mask to perform corresponding etching on the first substrate A surface of the first substrate, thereby forming a groove structure located in the middle of the first substrate A surface and removing the corresponding substrate shielding portion.

[0075] It should be noted that, in the present embodiment, "etching the first substrate A surface of the first substrate" can be performed by corresponding wet etching or dry etching, which depends on the material of the corresponding first substrate. For example, when the material of the first substrate is fused quartz or borosilicate glass, CHF3 or CF4 / H2 can be used for dry etching (etching parameters: temperature is about 15~20°C stable value, gas flow rate is 30~50Sccm, reaction pressure is 5~10mTorr), or HF solution can be used for wet etching (etching parameters: 40~50°C water bath heating, slight shaking. Special attention: before etching, ensure that the etching area is free of contamination and dry, which affects the HF contact and complete contact with the etching area); and when the material of the first substrate is silicon carbide, only SF6 / O2 can be used for dry etching (etching parameters: SF6 gas flow rate is 40~60Sccm, O2 / 10sccm, pressure is 10mTorr, ICP power1000W, RF power 400W, etching rate 11nm / s); when the material of the first substrate is sapphire, concentrated phosphoric acid / concentrated sulfuric acid mixture is required for wet etching (etching parameters: concentrated phosphoric acid / concentrated sulfuric acid mixture volume ratio 1:3, 200℃ hot plate heating, slight stirring).

[0076] In step S103, the following contents are included:

[0077] The first substrate and the second substrate are bonded to each other in a manner that the first substrate A surface of the first substrate is attached to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity.

[0078] For example, in this embodiment, Figure 4 As shown, after the formation of the corresponding groove structure is completed, the first substrate and the second substrate can be bonded in a manner that the first substrate A surface of the first substrate is adhered to the second substrate A surface of the second substrate. After the corresponding substrate bonding is completed, it can be determined that the groove structure corresponding to the first substrate should be formed into a corresponding sealed cavity, wherein the corresponding bonding parameters include: vacuum <2.5×10^-3Pa, bonding time more than 120 minutes, and bonding pressure and temperature vary according to the material (fused quartz: 4MPa, 900°C; silicon carbide: 4.5MPa, 1300°C; sapphire: 4MPa, 1200°C).

[0079] Further, in this embodiment, the above-mentioned “bonding the first substrate and the second substrate in a manner that the first substrate A surface of the first substrate is attached to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity” may also include the following steps:

[0080] In a vacuum environment, the first substrate and the second substrate are bonded by a thermal compression bonding process in a manner that the first substrate A surface of the first substrate is attached to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity.

[0081] For example, in this embodiment, the substrate bonding corresponding to the first substrate and the second substrate can be completed by using a corresponding thermocompression bonding process in a vacuum environment. It can be explained that thermocompression bonding (ThermocompressiveBonding) is a packaging technology that is widely used in micro-electromechanical systems (MEMS), 3D integration, chip stacking and other fields.

[0082] In step S104, the following contents are included:

[0083] A first UV protective layer is formed on the first substrate B surface of the first substrate, and the second substrate B surface of the second substrate is structured to form a first nanostructure layer located on the second substrate B surface, wherein the first nanostructure layer includes a plurality of first structure circular holes arranged in an array.

[0084] For example, in this embodiment, Figure 5 As shown, in order to prevent the first substrate from contacting the equipment table and being contaminated when the second substrate is subjected to the corresponding process, it is necessary to form a corresponding first UV protective layer on the first substrate to play a corresponding protective role; and after the formation of the first UV protective layer is completed, the second substrate B surface of the second substrate can be subjected to corresponding structural treatment to form a first nanostructure layer located on the second substrate B surface, wherein the first nanostructure layer includes a plurality of first structure circular holes arranged in an array.

[0085] It should be noted that, in this embodiment, the first substrate A surface and the first substrate A surface corresponding to the first substrate are respectively located on both sides of the first substrate, and the second substrate A surface and the second substrate B surface corresponding to the second substrate are also respectively located on both sides of the second substrate.

[0086] Furthermore, in this embodiment, the above-mentioned “performing a structural treatment on the second substrate surface B of the second substrate to form a first nanostructure layer located on the second substrate surface B” may further include the following steps:

[0087] forming a first nano-mask on the second substrate B surface of the second substrate by using nano-imprint technology;

[0088] The surface B of the second substrate is dry-etched based on the first nanomask, and the first nanomask is removed to form a first nanostructure layer located on the surface B of the second substrate.

[0089] For example, in this embodiment, Figure 6-Figure 7 As shown, in order to be able to process the first nanostructure layer with anti-reflection function on the second substrate B surface, the corresponding first nanomask can be formed on the corresponding second substrate B surface by using nanoimprint technology, and the second substrate B surface is further etched based on dry etching. After completing the corresponding etching treatment, the first nanomask is removed to obtain the corresponding first nanostructure layer.

[0090] It should be noted that, in this embodiment, in order to form the first nano-mask, a nano-imprinting process is required, and different methods can be used to form the corresponding mask for different substrate materials.

[0091] For example, when the material is fused quartz or borosilicate glass, a nanoimprint glue is needed as a mask. The nanoimprint glue used in this embodiment is PL-R-PC2000 from PuLin Technology (Hangzhou) Co., Ltd., which is a fluorine-based and chlorine-based plasma etching glue, used in conjunction with PL-R-AP viscosity enhancer, glue spreading process (smoothing PL-R-AP, 3500 rpm, baking in an oven at 120°C for 5 minutes, and immediate smearing of PL-R-PC2000, 3500 rpm), imprinting process (250KPa pressure, UV irradiation time 120s, using oxygen plasma to remove residual glue for nanoimprinting, O2 / 20sccm, CHF3 / 2sccm, Bias power 30W, etching rate 0.6-1.2nm / s);

[0092] For example, when the material is silicon carbide, metal Ni can be used as a mask and the lift-off process is adopted. The nanoimprint glue used in this patent comes from PL-R-UL1000-0 of PuLin Technology (Hangzhou) Co., Ltd. The glue spreading process (smoothing PL-R-AP, 3500 rpm, baking in a 120℃ oven for 5 minutes, and immediate spreading PL-R-UL1000-0, 3500 rpm), the imprinting process (250KPa pressure, UV irradiation time 120s, using oxygen plasma to remove the residual glue of nanoimprinting, O2 / 20sccm, CHF3 / 2sccm, ICP power 300W, RF power 30W, etching rate 0.6-1.2nm / s), electron beam evaporation of Ni film (vacuum degree <10^-6Torr, metal Cr, thickness 30nm), organic solvent ultrasonic stripping (pre-ultrasonication in acetone for 3 minutes, ultrasonication in anhydrous ethanol for 3 minutes, repeat anhydrous ethanol 2-3 times, rinse with deionized water, and dry on a hot plate);

[0093] For example, when the material is sapphire, a multilayer mask of "nanoimprint glue / Cr / silicon oxide" can be used to first deposit 300nm silicon oxide (SiH4 / 130sccm, O2 / 13sccm, Ar / 32.5sccm, temperature 130℃, pressure 0.8Pa, time 1000s), then use electron beam to evaporate 30nmCr (vacuum degree <10^-6Torr, metal Cr, thickness 30nm), the nanoimprint glue used in this patent comes from PL-R-UL1000-0 of PuLin Technology (Hangzhou) Co., Ltd., glue spreading process (smoothing PL-R-AP, 3500 rpm, baking in 120℃ oven for 5min, need to immediately spread PL-R-UL1000-0, 3500 rpm), imprinting process (250KPa pressure, UV irradiation time 120s, use oxygen plasma to remove residual glue of nanoimprinting, O2 / 20sccm, CHF3 / 2sccm, ICP power 300W, pressure 10mTorr, RF power 30W, etching rate 2.7nm / s), etching process (Cr etching: Cl2 / 23.2 sccm, O2 6.8sccm, pressure 10mTorr, pressure ICP power 500W, RF power 25W, etching rate 0.6nm / s; SiO2 etching: CF4 / 80sccm, H2 / 2sccm, pressure 10mTorr, ICP power500W, RF power 80W, etching rate 2.7nm / s.

[0094] It should be noted that since the preparation of the nanostructure layer has high requirements for etching technology, it is necessary to ensure that the size of the etched structure meets the design requirements. In particular, the corresponding dry etching process and conventional etching process remain similar, but are prone to "micro-loading effects", so it is necessary to ensure that the amount of plasma involved in the reaction is sufficient, and the gas flow rate can be doubled to keep the ratio unchanged.

[0095] In addition, the etching parameters for different materials can be described as follows:

[0096] Fused silica etching: CF4 / 95sccm, O2 / 5sccm, pressure 5mTorr, ICP power 1000W, RF power50W, etching rate 5.2nm / s; Silicon carbide etching: SF6 / 50sccm, O2 / 10sccm, pressure 10mTorr, ICP power1000W, RF power 400W, etching rate 11nm / s); Sapphire etching: BCl3 / 80sccm, Cl2 / 30sccm, pressure 10mTorr, ICP power 500W, RF power 100W, etching rate 0.3nm / s).

[0097] In step S105, the following contents are included:

[0098] The first UV protective layer is removed, a second UV protective layer is formed on the second substrate B surface of the second substrate, and the first substrate B surface of the first substrate is structured to form a second nanostructure layer located on the first substrate B surface, wherein the second nanostructure layer includes a plurality of second structure circular holes arranged in an array.

[0099] For example, in this embodiment, after completing the preparation of the corresponding first nanostructure layer, the first UV protective layer corresponding to the first substrate B surface can be removed, so as to prepare the second nanostructure layer corresponding to the first substrate B surface of the first substrate based on a process similar to the preparation of the first nanostructure layer, thereby forming two nanostructures on both sides and distributed in opposite directions.

[0100] Further, in this embodiment, the above-mentioned “removing the first UV protective layer and forming a second UV protective layer on the second substrate B surface of the second substrate” may also include the following steps:

[0101] irradiating the first UV protective layer with ultraviolet light for a preset irradiation time to perform a photolysis process corresponding to the first UV protective layer;

[0102] After the photolysis process of the first UV protective layer is completed, the first UV protective layer is removed, and a second UV protective layer is formed on the second substrate B surface of the second substrate.

[0103] For example, Figure 8-Figure 9As shown, when removing the first UV protective layer, the first UV protective layer can be photolyzed by utilizing ultraviolet irradiation to eliminate the stickiness of the first UV protective layer, so that the first UV protective layer can be torn off, so that there is no residual substance corresponding to the first UV protective layer on the B surface of the first substrate; here, the corresponding preset irradiation time is not less than 300 seconds, for example, it can be 350 seconds; and after completing the removal of the corresponding first UV protective layer, the corresponding second UV protective layer can be further formed on the B surface of the second substrate.

[0104] For example, in this embodiment, based on the above content, it can be known that the removal of the first UV protective layer is generally carried out based on ultraviolet light irradiation, that is, the viscosity of the first UV protective layer is eliminated by utilizing ultraviolet irradiation, thereby facilitating the removal of the first UV protective layer. However, in some cases, due to the ultraviolet irradiation range, irradiation intensity, irradiation time and the material of the corresponding first UV protective layer, corresponding residual substances may still remain on the first substrate B surface during the corresponding ultraviolet irradiation, thereby affecting the corresponding preparation quality when the corresponding second nanostructure layer is subsequently prepared on the first substrate B surface.

[0105] Based on the above content, in this embodiment, how to identify the residual substances in real time and further remove the residual substances obtained by the corresponding identification can be carried out based on the following technical methods:

[0106] When the removal of the first UV protective layer is completed, the acquisition unit is controlled to acquire an image of the surface B of the first substrate, and image recognition is performed on the acquired substrate image;

[0107] When it is determined based on the recognition result that noise regions corresponding to different residual substances exist in the substrate acquisition image, the number of regions corresponding to each noise region and the region proportion corresponding to each noise region are obtained;

[0108] The area quantity and area proportion are respectively multiplied by the retrieved normalized value of quantity and normalized value of proportion to obtain an initial quantity evaluation value and an initial area evaluation value;

[0109] The initial quantity evaluation value and the initial area evaluation value are respectively multiplied by the retrieved quantity weight value and the area weight value to obtain the current quantity evaluation value of the corresponding quantity dimension and the current area evaluation value of the corresponding area dimension;

[0110] Based on the sum of the current quantity evaluation value and the current area evaluation value, obtaining a residual evaluation value corresponding to the first UV protective layer;

[0111] The residue evaluation value is compared with a preset evaluation threshold, and when the residue evaluation value is greater than or equal to the preset evaluation threshold, the surface B of the first substrate is determined to be unqualified.

[0112] For example, in this embodiment, after the stripping operation of the first UV protective layer is completed, the corresponding acquisition unit (such as a camera) may be instructed to perform image acquisition on the surface B of the first substrate, and perform image recognition processing on the acquired substrate acquisition image, so as to determine whether there is residual material corresponding to the first UV protective layer on the surface B of the first substrate based on the substrate acquisition image. Here, the image processing may be performed based on a corresponding neural network learning model or a machine learning model. Since the corresponding image recognition processing is a prior art, this embodiment will not be described in detail.

[0113] When it is determined based on the result of image recognition that there are noise regions corresponding to different residual substances in the substrate acquisition image, the number of regions corresponding to the noise regions and their area proportions in the substrate acquisition image can be further extracted. Here, the area proportion can be understood as the area ratio between the area corresponding to each noise region and the image area of ​​the corresponding substrate acquisition image;

[0114] Subsequently, the number of regions extracted above is multiplied by the retrieved normalized reference value of the number to obtain an initial number evaluation score; at the same time, the area ratio of each noise region is multiplied by the retrieved normalized reference value of the ratio to obtain an initial area evaluation score. This step normalizes the corresponding number of regions and area ratios respectively, thereby facilitating subsequent numerical calculations;

[0115] Next, the retrieved quantity weight value and area weight value are used to weight the initial quantity evaluation score and the initial area evaluation score, respectively, so as to calculate the current quantity evaluation score corresponding to the quantity dimension and the current area evaluation score corresponding to the area dimension;

[0116] By performing a sum operation on the current quantity evaluation score and the current area evaluation score, a residual evaluation value corresponding to the residual condition of the first UV protective layer can be generated;

[0117] Finally, the residual evaluation value is compared with a preset evaluation threshold. If the former is greater than or equal to the latter, the first substrate surface B can be automatically determined to be unqualified and needs to be scrapped accordingly.

[0118] It can be explained that, in this embodiment, since the residual evaluation value is obtained based on automated calculation, it may differ from the actual situation. In order to improve the corresponding determination accuracy, the corresponding quantity weight value and area weight value can be updated and adjusted in real time to realize the process of updating and iterating each weight value, thereby continuously improving the corresponding determination accuracy.

[0119] Therefore, further, in this embodiment, the following steps may also be included:

[0120] Obtaining an actual evaluation value inputted by the preparation process end based on the residual evaluation value, and comparing the residual evaluation value with the actual evaluation value by score;

[0121] When the actual evaluation value is greater than the residual evaluation value, increasing training is performed on the quantity weight value and the area weight value;

[0122] When the actual evaluation value is greater than the residual evaluation value, the quantity weight value and the area weight value are reduced by training;

[0123] The number weight value and area weight value after training are obtained through the following formula:

[0124] in, is the quantity weight value Increase the number of training sessions. is the quantity weight value The training constant value of is the quantity weight value Reduce the number of training sessions. is the quantity weight value after training, is the area weight value Increase the number of training sessions. is the area weight value The training constant value of is the area weight value Reduce the number of training sessions. is the area weight value after training.

[0125] It should be noted that, in this embodiment, the above-mentioned preparation process end can be understood as a terminal device used by the corresponding preparation process personnel. The preparation process end has corresponding data processing functions and data transmission functions, which may specifically include a mobile phone or a computer.

[0126] Based on the above content, it can be known that when the corresponding residual evaluation value is greater than or equal to the preset evaluation threshold, the residual material on the surface of the first substrate B is relatively large, and therefore, the corresponding first substrate B surface can be directly determined to be unqualified, that is, the corresponding first substrate and the second substrate after substrate bonding need to be scrapped to re-carry out the corresponding preparation method to improve the preparation efficiency; and when the corresponding residual evaluation value is less than the preset evaluation threshold, the corresponding repair process can be performed on the corresponding first substrate B surface, so as to ensure that the residual material on the first substrate B surface can be removed. Therefore, in this embodiment, the corresponding removal process can be described as follows:

[0127] When the residual evaluation value is less than the preset evaluation threshold, coordinate processing is performed on the substrate acquisition image to obtain the image coordinate points constituting the substrate acquisition image;

[0128] Determine the image coordinate points constituting each noise area as a noise coordinate group, and determine the image coordinate points corresponding to the X-axis maximum value, the X-axis minimum value, the Y-axis maximum value, and the Y-axis minimum value as the X-axis maximum coordinate point, the X-axis minimum coordinate point, the Y-axis maximum coordinate point, and the Y-axis minimum coordinate point based on the noise coordinate group;

[0129] A first X-axis extension line and a second X-axis extension line are established along the X-axis maximum coordinate point and the X-axis minimum coordinate point as starting points, respectively, and the first Y-axis extension line and the second Y-axis extension line are established along the Y-axis maximum coordinate point and the Y-axis minimum coordinate point as starting points, respectively, and the X-axis of the corresponding image coordinate system.

[0130] Generate a noise frame surrounding each noise area based on the first X-axis extension line, the second X-axis extension line, the first Y-axis extension line, and the second Y-axis extension line, and obtain a frame center point corresponding to the noise frame;

[0131] Taking the center point of the frame as the irradiation center, ultraviolet rays are used to continuously irradiate the B surface of the first substrate for a preset irradiation time, and after the irradiation is completed, a cleaning operation is performed on the B surface of the first substrate.

[0132] For example, in this embodiment, under the condition that the residual evaluation value does not reach the preset evaluation threshold, the following steps are performed to process the substrate acquisition image obtained above:

[0133] First, coordinate processing is performed on the substrate captured image, so as to accurately obtain all image coordinate points constituting the image;

[0134] Next, the image coordinate points constituting each noise area are identified and extracted to form a noise coordinate group. Based on the noise coordinate group, the coordinate point with the maximum value on the X-axis (X-axis maximum coordinate point), the coordinate point with the minimum value on the X-axis (X-axis minimum coordinate point), the coordinate point with the maximum value on the Y-axis (Y-axis maximum coordinate point), and the coordinate point with the minimum value on the Y-axis (Y-axis minimum coordinate point) are determined respectively.

[0135] Subsequently, the first X-axis extension line and the second X-axis extension line perpendicular to the Y-axis of the image coordinate system are constructed respectively with the maximum X-axis coordinate point and the minimum X-axis coordinate point as starting points. Similarly, the first Y-axis extension line and the second Y-axis extension line perpendicular to the X-axis of the image coordinate system are constructed respectively with the maximum Y-axis coordinate point and the minimum Y-axis coordinate point as starting points.

[0136] Next, using the above four extension lines, a noise frame that completely surrounds all noise areas is generated, and the center point of the noise frame, i.e., the frame center point, is calculated;

[0137] Finally, with the center point of the frame as the irradiation center, the first substrate surface B is irradiated with light for a preset time. After the irradiation is completed, the first substrate surface B can be further cleaned to completely remove residual substances.

[0138] It should be noted that by obtaining the corresponding noise frame, ultraviolet-based light irradiation can be further performed based on the frame center point corresponding to the noise frame, thereby ensuring that the ultraviolet light can irradiate the noise frame completely, so that all noise areas are exposed to ultraviolet-based light irradiation to improve the corresponding removal effect; here, the corresponding cleaning operation can be a standard cleaning method, such as: RCA-1 or RCA-3, etc.

[0139] Furthermore, in this embodiment, the above-mentioned “performing a structural treatment on the first substrate surface B of the first substrate to form a second nanostructure layer located on the first substrate surface B” may further include the following steps:

[0140] forming a second nanomask on the first substrate B surface of the first substrate by using nanoimprint technology;

[0141] The surface B of the first substrate is dry-etched based on the second nanomask, and the second nanomask is removed to form a second nanostructure layer located on the surface B of the first substrate.

[0142] For example, in this embodiment, the preparation process of the second nanostructure layer is similar to that of the first nanostructure layer, both of which involve etching the corresponding substrate surface based on dry etching on the basis of forming a corresponding nanomask. Therefore, the preparation process of the second nanostructure layer will not be described in detail.

[0143] In step S106, the following contents are included:

[0144] The second UV protective layer is removed to obtain a double-sided nanoimprint structure.

[0145] For example, in this embodiment, Fig.10 As shown, after the preparation of the corresponding second nanostructure layer is completed, the second UV protective layer can be removed in the same manner as the first UV protective layer, thereby completing the preparation of the corresponding double-sided nanoimprint structure.

[0146] In summary, according to the scheme provided in this embodiment, this embodiment successfully prepares an imprinted structure with a double-sided nanostructure by sequentially performing patterning of a photoresist coating, etching, substrate bonding, formation and removal of a UV protective layer, and application of nanoimprint technology on a substrate. The key lies in the application and removal of the UV protective layer, which can effectively improve the surface quality of the nanostructure. Specifically, the double-sided nanostructure layer obtained based on this embodiment can effectively enhance the optical properties of the material, reduce the reflection loss of light, and improve the transmittance of light, and is suitable for optical devices, sensors and other fields. In addition, this embodiment can further ensure the high precision and large-area uniformity of the nanostructure through precise etching and nanoimprinting processes, thereby improving the preparation efficiency and consistency.

[0147] Another embodiment of the present invention provides a double-sided nanoimprint structure prepared based on the above-mentioned preparation method of the double-sided nanoimprint structure. The double-sided nanoimprint structure can be Fig.10 As shown, it specifically includes:

[0148] a first substrate and a second substrate;

[0149] Among them, the first substrate B surface of the first substrate and the second substrate B surface of the second substrate are respectively formed with a second nanostructure layer including a plurality of second structure circular holes arranged in an array and a first nanostructure layer including a plurality of first structure circular holes arranged in an array, the first substrate A surface of the first substrate is formed with a groove structure, and the first substrate A surface of the first substrate is adhered to the first substrate A surface of the second substrate, so that the groove structure forms a sealed cavity.

[0150] For example, in the processing of double-sided nanoimprint structures based on sapphire materials, some processes and physical objects can be specifically Figure 11-Figure 15 As shown, Fig.11 A schematic diagram showing the deposition of SiO2 thin film based on PECVD using a UV protective layer when processing a sapphire double-sided nanoimprint structure in this embodiment; Fig.12 The actual image of the sapphire double-sided nanoimprint structure processed in this embodiment is shown; Fig.13 The front view SEM result image of the nanostructure layer of the sapphire double-sided nanoimprint structure processed in this embodiment is shown; Fig.14 The cross-sectional SEM result image of the nanostructure layer of the sapphire double-sided nanoimprint structure processed in this embodiment is shown; Fig.15 The cross-sectional oblique SEM result image of the nanostructure layer of the sapphire double-sided nanoimprint structure processed in this embodiment is shown.

[0151] In the description provided herein, algorithms and displays are not inherently related to any particular computer, virtual system or other device. Various general purpose systems can also be used together with the examples of the present invention. According to the above description, it is obvious that the structure required for constructing such systems. In addition, the present invention is not directed to any specific programming language either. It should be understood that various programming languages ​​can be utilized to implement the content of the present invention described herein, and the above description of specific languages ​​is for the purpose of disclosing the preferred embodiment of the present invention.

[0152] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0153] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof.

[0154] Those skilled in the art will appreciate that the modules or units or components of the devices in the examples disclosed herein may be arranged in the devices described in the embodiment, or alternatively may be located in one or more devices different from the devices in the examples. The modules in the foregoing examples may be combined into one module or may be divided into multiple submodules.

[0155] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and furthermore may be divided into a plurality of submodules or subunits or subcomponents.

[0156] Furthermore, those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features from different embodiments is meant to be within the scope of the present invention and to form different embodiments.

[0157] In addition, some of the embodiments are described herein as methods or combinations of method elements that can be implemented by a processor of a computer system or by other devices that perform the functions. Therefore, a processor with necessary instructions for implementing the method or method elements forms a device for implementing the method or method elements. In addition, the elements described herein of the device embodiments are examples of devices for implementing the functions performed by the elements for the purpose of implementing the invention.

[0158] As used herein, unless otherwise specified, the use of ordinal numbers "first," "second," "third," etc. to describe common objects merely indicates that different instances of similar objects are involved, and is not intended to imply that the objects so described must have a given order in time, space, order, or in any other manner.

[0159] Although the present invention has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the invention thus described. In addition, it should be noted that the language used in this specification is primarily selected for readability and instructional purposes, rather than for explaining or limiting the subject matter of the present invention.

Claims

1. A method for preparing a double-sided nanoimprint structure, characterized in that: The following steps are involved: Forming a first photoresist coating on the first substrate A surface of the first substrate, and performing patterning based on the first photoresist coating to obtain substrate shielding portions corresponding to the first photoresist coating and located on both sides of the first substrate A surface; Etching the first substrate surface A of the first substrate to form a groove structure located in the middle of the first substrate surface A, and removing the substrate shielding portion; Bonding the first substrate and the second substrate in a manner that the first substrate A surface of the first substrate is attached to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity; forming a first UV protective layer on the first substrate surface B of the first substrate, and performing a structural treatment on the second substrate surface B of the second substrate to form a first nanostructure layer located on the second substrate surface B, wherein the first nanostructure layer includes a plurality of first structure circular holes arranged in an array; removing the first UV protective layer, forming a second UV protective layer on the second substrate surface B of the second substrate, and performing a structural treatment on the first substrate surface B of the first substrate to form a second nanostructure layer located on the first substrate surface B, wherein the second nanostructure layer includes a plurality of second structure circular holes arranged in an array; The second UV protective layer is removed to obtain a double-sided nanoimprint structure.

2. The method for preparing a double-sided nanoimprint structure according to claim 1, characterized in that: Etching the first substrate surface A of the first substrate includes: wet-etching the first substrate surface A of the first substrate; or, The first substrate A surface of the first substrate is dry-etched.

3. The method for preparing a double-sided nanoimprint structure according to claim 1, characterized in that: The first substrate and the second substrate are bonded in a manner that the first substrate A surface of the first substrate is attached to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity, including: In a vacuum environment, the first substrate and the second substrate are bonded by a thermal compression bonding process in a manner that the first substrate A surface of the first substrate is attached to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity.

4. The method for preparing a double-sided nanoimprint structure according to claim 1, characterized in that: Performing a structural treatment on the second substrate surface B of the second substrate to form a first nanostructure layer located on the second substrate surface B, comprising: forming a first nano-mask on the second substrate B surface of the second substrate by using nano-imprint technology; The surface B of the second substrate is dry-etched based on the first nanomask, and the first nanomask is removed to form a first nanostructure layer located on the surface B of the second substrate.

5. The method for preparing a double-sided nanoimprint structure according to claim 1, characterized in that: Removing the first UV protective layer and forming a second UV protective layer on the second substrate B surface of the second substrate, comprising: irradiating the first UV protective layer with ultraviolet light for a preset irradiation time to perform a photolysis process corresponding to the first UV protective layer; After the photolysis process of the first UV protective layer is completed, the first UV protective layer is removed, and a second UV protective layer is formed on the second substrate B surface of the second substrate.

6. The method for preparing a double-sided nanoimprint structure according to claim 5, characterized in that: The first UV protective layer is removed, and then the method further comprises: When the removal of the first UV protective layer is completed, the acquisition unit is controlled to acquire an image of the surface B of the first substrate, and image recognition is performed on the acquired substrate image; When it is determined based on the recognition result that noise regions corresponding to different residual substances exist in the substrate acquisition image, the number of regions corresponding to the noise regions and the region proportion corresponding to the noise regions are obtained; The area quantity and area proportion are respectively multiplied by the retrieved normalized value of quantity and normalized value of proportion to obtain an initial quantity evaluation value and an initial area evaluation value; The initial quantity evaluation value and the initial area evaluation value are respectively multiplied by the retrieved quantity weight value and the area weight value to obtain the current quantity evaluation value of the corresponding quantity dimension and the current area evaluation value of the corresponding area dimension; Based on the sum of the current quantity evaluation value and the current area evaluation value, obtaining a residual evaluation value corresponding to the first UV protective layer; The residue evaluation value is compared with a preset evaluation threshold, and when the residue evaluation value is greater than or equal to the preset evaluation threshold, the surface B of the first substrate is determined to be unqualified.

7. The method for preparing a double-sided nanoimprint structure according to claim 6, characterized in that: The method further comprises: Obtaining an actual evaluation value inputted by the preparation process end based on the residual evaluation value, and comparing the residual evaluation value with the actual evaluation value by score; When the actual evaluation value is greater than the residual evaluation value, increasing training is performed on the quantity weight value and the area weight value; When the actual evaluation value is greater than the residual evaluation value, the quantity weight value and the area weight value are reduced by training; The number weight value and area weight value after training are obtained through the following formula: in, is the quantity weight value Increase the number of training sessions. is the quantity weight value The training constant value of is the quantity weight value Reduce the number of training sessions. is the quantity weight value after training, is the area weight value Increase the number of training sessions. is the area weight value The training constant value of is the area weight value Reduce the number of training sessions. is the area weight value after training.

8. The method for preparing a double-sided nanoimprint structure according to claim 6, characterized in that: The method further comprises: When the residual evaluation value is less than the preset evaluation threshold, coordinate processing is performed on the substrate acquisition image to obtain the image coordinate points constituting the substrate acquisition image; Determine the image coordinate points constituting each noise area as a noise coordinate group, and determine the image coordinate points corresponding to the X-axis maximum value, the X-axis minimum value, the Y-axis maximum value, and the Y-axis minimum value as the X-axis maximum coordinate point, the X-axis minimum coordinate point, the Y-axis maximum coordinate point, and the Y-axis minimum coordinate point based on the noise coordinate group; A first X-axis extension line and a second X-axis extension line are established along the X-axis maximum coordinate point and the X-axis minimum coordinate point as starting points, respectively, and the first Y-axis extension line and the second Y-axis extension line are established along the Y-axis maximum coordinate point and the Y-axis minimum coordinate point as starting points, respectively, and the X-axis of the corresponding image coordinate system. Generate a noise frame surrounding each noise area based on the first X-axis extension line, the second X-axis extension line, the first Y-axis extension line, and the second Y-axis extension line, and obtain a frame center point corresponding to the noise frame; Taking the center point of the frame as the irradiation center, ultraviolet rays are used to continuously irradiate the B surface of the first substrate for a preset irradiation time, and after the irradiation is completed, a cleaning operation is performed on the B surface of the first substrate.

9. The method for preparing a double-sided nanoimprint structure according to claim 1, characterized in that: Performing a structural treatment on the first substrate surface B of the first substrate to form a second nanostructure layer located on the first substrate surface B, comprising: forming a second nanomask on the first substrate B surface of the first substrate by using nanoimprint technology; The surface B of the first substrate is dry-etched based on the second nanomask, and the second nanomask is removed to form a second nanostructure layer located on the surface B of the first substrate.

10. A double-sided nanoimprint structure prepared by the method for preparing a double-sided nanoimprint structure according to any one of claims 1 to 9, characterized in that: include: a first substrate and a second substrate; Among them, the first substrate B surface of the first substrate and the second substrate B surface of the second substrate are respectively formed with a second nanostructure layer including a plurality of second structure circular holes arranged in an array and a first nanostructure layer including a plurality of first structure circular holes arranged in an array, the first substrate A surface of the first substrate is formed with a groove structure, and the first substrate A surface of the first substrate is adhered to the second substrate A surface of the second substrate, so that the groove structure forms a sealed cavity.

Images