Large-area highly ordered array structure and preparation method thereof

Abstract

The invention provides a large-area highly-ordered array structure and a preparation method thereof, and the preparation method comprises the steps: firstly, sequentially carrying out the cutting, cleaning, drying and surface activation treatment of a substrate, and obtaining a pretreated substrate; secondly, coating photoresist on the surface of the pretreated substrate, and carrying out primary baking treatment on the coated photoresist; thirdly, performing exposure treatment on the photoresist by using a diffraction grating element in combination with a coherent light source to obtain an initial patterned photoresist; the diffraction grating element comprises a plurality of square transmission gratings, and the plurality of square transmission gratings integrally form an included angle of 30-150 degrees in spatial arrangement; thirdly, sequentially carrying out post-baking, developing and photographic fixing treatment on the initial patterned photoresist to obtain ordered patterned photoresist; and finally, carrying out etching treatment on the substrate by taking the ordered patterning photoresist as a mask, removing the residual ordered patterning photoresist after etching is completed, and finally forming a large-area highly ordered array structure on the substrate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of micro-nano processing manufacturing technology, and particularly relates to a large-area highly ordered array structure and a preparation method thereof. BACKGROUND

[0002] In recent years, large-area, highly uniform and ordered micro-nano structures have attracted much attention in many fields such as sensing analysis and detection, solar spectrum absorption and photo-thermal conversion. At present, various micro-nano structure preparation methods have been developed, such as nano-imprinting technology, electron beam lithography technology and focused ion beam lithography technology. For example, Chinese patent CN102591140A discloses a nano-imprinting method without residual layer, which eliminates the additional process of removing the residual layer by reactive ion etching in the traditional nano-imprinting technology; Chinese patent CN103676492A discloses an electron beam lithography method which can effectively improve the line width roughness. However, the structure prepared by nano-imprinting method completely depends on the used template, and the imprinting template is easily contaminated and damaged during use; although the electron beam and focused ion beam lithography technology can directly "write" the preset pattern on the substrate, the processing area is usually only tens of microns, which not only takes a long time, but also the related instruments are very expensive.

[0003] The principle of the traditional mask plate exposure method is that ultraviolet light is irradiated onto a mask plate designed and processed in advance, part of the incident light is blocked by the pattern on the mask plate, and the remaining light transmits through the mask plate to transfer the pattern information to the surface of the substrate coated with photoresist, and the final pattern topography is obtained after development. However, this method can only obtain the same or complementary topography as the mask plate pattern, and cannot further flexibly control the pattern topography.

[0004] Therefore, there is an urgent need for a large-area highly ordered array structure and a preparation method thereof to solve the above technical problems. SUMMARY

[0005] The present application aims to solve the technical problem that the existing micro-nano processing manufacturing technology cannot prepare a large-area highly ordered array structure with high precision.

[0006] To solve the above technical problems, the present application first provides a preparation method of a large-area highly ordered array structure, comprising: S10, sequentially cutting, cleaning, drying and surface activating the substrate to obtain a pretreated substrate; S20, coating photoresist on the surface of the pretreated substrate and performing preliminary baking treatment on the coated photoresist; S30, exposing the photoresist by using a diffraction grating element combined with a coherent light source to obtain an initial patterned photoresist; the diffraction grating element comprises a plurality of square transmission gratings, and the plurality of square transmission gratings are arranged at an angle of 30°-150° with respect to each other. S40, sequentially performing post-baking, developing and fixing treatment on the initial patterned photoresist, to obtain an ordered patterned photoresist; S50, performing etching treatment on the substrate with the ordered patterned photoresist as a mask, and removing the residual ordered patterned photoresist after the etching is completed, to finally form a large-area high-ordered array structure on the substrate.

[0007] Preferably, the cleaning treatment in the step S10 comprises: firstly performing ultrasonic treatment on the substrate, then immersing the substrate in the piranha solution at 250℃, and finally blowing the substrate dry with nitrogen.

[0008] Preferably, the surface activation treatment in the step S10 comprises: bombarding the substrate with oxygen plasma, with a power of 45-55 mW and a time length of 2-4 min.

[0009] Preferably, in the step S20, the photoresist is SU-8 2000.5 negative photoresist.

[0010] Preferably, the step of coating the photoresist in the step S20 comprises: firstly spin-coating at a speed of 400-600 rad / min for 4-6 s, and then spin-coating at a speed of 3500-4500 rad / min for 35-45 s.

[0011] Preferably, the step of the preliminary baking treatment in the step S20 comprises: firstly baking the coated photoresist at 60-70℃ for 55-65 s, and then baking the coated photoresist at 90-100℃ for 55-65 s.

[0012] Preferably, in the step S30: the diffractive grating element comprises three square transmission gratings, and the three square transmission gratings are arranged at an overall included angle of 120°.

[0013] Preferably, in the step S30, the exposure treatment comprises: an exposure wavelength of 266 nm, a full power of the coherent light source of 100-120 mW, and an exposure time of 8-12 s.

[0014] Preferably, in the step S40: the post-baking temperature is 70-80℃, the post-baking time is 0.5-1.5 min; the developing solution used for developing is propylene glycol methyl ether acetate, the developing time is 1-2 min; and the fixing solution used for fixing is isopropyl alcohol, and the fixing time is 2-3 min.

[0015] Correspondingly, the application also provides a large-area high-ordered array structure prepared by any one of the preparation methods of the large-area high-ordered array structure. The processing area size of the large-area high-ordered array structure reaches a centimeter level.

[0016] The beneficial effects of the present application are: different from the prior art, the present application provides a large-area highly ordered array structure and a preparation method thereof, the preparation method comprises the following steps: firstly, the substrate is sequentially subjected to cutting, cleaning, drying and surface activation treatment to obtain a pretreated substrate; secondly, photoresist is coated on the surface of the pretreated substrate, and the coated photoresist is subjected to preliminary baking treatment; thirdly, the photoresist is subjected to exposure treatment by using a diffraction grating element combined with a coherent light source to obtain an initial patterned photoresist; the diffraction grating element comprises a plurality of square transmission gratings, and the plurality of square transmission gratings are arranged at an angle of 30°-150° with each other; fourthly, the initial patterned photoresist is sequentially subjected to post-baking, development and fixing treatment to obtain an ordered patterned photoresist; finally, the substrate is subjected to etching treatment by taking the ordered patterned photoresist as a mask, and the residual ordered patterned photoresist is removed after etching is completed, and finally a large-area highly ordered array structure is formed on the substrate. The preparation method of the present application uses diffraction grating interference exposure technology, does not need to rely on a specific template, can avoid the pollution and loss problems of the traditional template, can realize large-area processing to break through the limitation of small-area processing, can flexibly adjust the pattern morphology by adjusting parameters such as grating angle, can reduce the equipment cost and process complexity, comprehensively solves the core defects of the prior art, and is suitable for large-scale preparation of large-area highly ordered array structures. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The preparation method flow chart of the large-area highly ordered array structure provided for the embodiments of the present application; Figure 2 The structure schematic diagram of the diffraction grating element composed of three square transmission gratings intersecting at an angle of 120° provided for the embodiment 1 of the present application; Figure 3 The substrate pattern actuality diagram prepared for the embodiment 1 of the present application; Figure 4 The hexagonal array morphology structure schematic diagram prepared for the embodiment 1 of the present application.

[0018] Figure 5 The scanning electron microscope image of the hexagonal array structure prepared for the embodiment 1 of the present application.

[0019] Figure 6 The fishbone-shaped array morphology structure schematic diagram prepared for the embodiment 2 of the present application.

[0020] Figure 7 The scanning electron microscope image of the fishbone-shaped array structure prepared for the embodiment 2 of the present application.

[0021] Figure 8 The rod-shaped array morphology structure schematic diagram prepared for the embodiment 3 of the present application.

[0022] Figure 9 A scanning electron microscope image of the rod array structure prepared in Example 3 of the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0024] In order to overcome the defects and deficiencies of the prior art, the purpose of the present application is to provide a large-area highly ordered array structure and a preparation method thereof. The method is to irradiate a pattern formed by superimposing multiple beams of diffracted light onto a substrate coated with photoresist by irradiating ultraviolet light onto a mask containing multiple square transmission gratings intersecting at an angle of 30°~150°. After development, a large-area highly ordered array pattern is obtained. By changing the superimposition effect of the diffracted light, array patterns with different topographic structures can be obtained.

[0025] In order to achieve the above technical purpose, the present application adopts the following technical solutions: In the first aspect, refer to Figure 1 , Figure 1 The preparation method flow chart of the large-area highly ordered array structure provided by the embodiment of the present application; wherein the preparation method specifically comprises: S10, the substrate is sequentially cut, cleaned, dried and surface activated to obtain a pretreated substrate.

[0026] Specifically, the S10 step further comprises: First, the substrate (such as a silicon wafer) is cut, the cut substrate is cleaned, and then the substrate is dried and activated to obtain a pretreated substrate.

[0027] Specifically, the cutting instrument in the S10 step can be a laser scribing machine, and each piece of cut substrate is a square of 2.4cm×2.4cm. Laser scribing machine cutting can achieve high-precision cutting to obtain square substrates of 2.4cm×2.4cm in size, ensuring the consistency of the substrate specifications in batch processing and avoiding process deviations in subsequent glue coating, exposure and other links due to differences in substrate size.

[0028] Specifically, the cleaning process in the S10 step includes: first, rinsing the substrate with water, then performing 15 min ultrasonic treatment on the substrate with acetone and ethanol respectively, subsequently immersing the substrate in a "piranha" solution at 250℃ for 15 min, and finally blowing the substrate dry with nitrogen; wherein the "piranha" solution is a mixture of 30% hydrogen peroxide solution and 98% sulfuric acid solution with a volume ratio of 1:3.

[0029] Specifically, the surface activation treatment in the S10 step includes: bombarding the substrate with oxygen plasma, with a power of 45~55mW (preferably 50mW) and a duration of 2~4min (preferably 3min).

[0030] Further, the multi-step cleaning process in the S10 step forms complementary purification effects: water rinsing can preliminarily remove surface dust, 15min ultrasonic treatment with acetone and ethanol can efficiently strip organic contaminants, the "piranha" solution (a mixture of hydrogen peroxide solution and sulfuric acid with a volume ratio of 1:3) at 250℃ can deeply remove residual inorganic impurities and oxidize the substrate surface due to its strong oxidizing property, and blowing dry with nitrogen can prevent water stains from remaining and secondary pollution, thereby ensuring that the substrate surface reaches lithography-level cleanliness; oxygen plasma bombardment can further activate the substrate surface, which can not only increase active groups such as hydroxyl groups to improve hydrophilicity, but also enhance the adhesion between the subsequent photoresist and the substrate through slight surface roughening, thereby reducing the risk of pinholes, bubbles during photoresist coating, and pattern peeling during development and etching.

[0031] S20, after the pretreatment, coating photoresist on the surface of the substrate, and performing preliminary baking treatment on the coated photoresist.

[0032] Specifically, the photoresist is SU-8 2000.5 negative photoresist, the polymer molecules of which are epoxy resins, and the acid generator is diphenylsulfonium hexafluoroantimonate; the above-mentioned SU-8 2000.5 negative photoresist itself has excellent chemical stability and etching resistance, and can serve as a reliable mask to support subsequent etching processes; and the negative photosensitive characteristics are completely matched with the patterning logic of "exposed area retention, unexposed area removal" of the present application, and can accurately convert the latent image pattern formed by interference exposure.

[0033] Specifically, the step of coating photoresist in the S20 step by using the spin coating method specifically includes: first, spin coating at a speed of 400~600rad / min (preferably 500rad / min) for 4~6s (preferably 5s), and then spin coating at a speed of 3500~4500rad / min (preferably 4000rad / min) for 35~45s (preferably 40s); wherein the two-stage spin coating process can accurately control the thickness of the photoresist (adapted to the viscosity characteristics of SU-8 2000.5) through centrifugal force, thereby ensuring the uniformity of the photoresist layer thickness in a large area, and providing a prerequisite for "uniform light response" of the S30 interference exposure and "pattern transfer precision" of the S50 etching.

[0034] Specifically, the step of the preliminary baking treatment in the S20 step specifically comprises: first baking the coated photoresist at 60-70°C (preferably 65°C) for 55-65s (preferably 60s), and then baking the coated photoresist at 90-100°C for 55-65s (preferably 60s).

[0035] Further, the low-temperature baking at 60-70°C can slowly remove most of the solvent in the glue layer, avoiding bubbles, pinholes or cracking of the glue layer due to rapid evaporation of the solvent; the subsequent high-temperature baking at 90-100°C can further remove the residual solvent and promote the leveling of the glue layer, while enhancing the interfacial adhesion of the photoresist to the substrate activated in the S10 step (reducing defects such as pinholes and peeling). The step-by-step temperature rise avoids the problems of "uneven solvent evaporation" or "insufficient adhesion" of single-temperature baking, ensuring that the glue layer is dense, flat and firmly bonded to the substrate.

[0036] S30, using a diffraction grating element combined with a coherent light source to expose the photoresist to obtain an initial patterned photoresist; the diffraction grating element includes a plurality of square transmission gratings, and the plurality of square transmission gratings are arranged at an angle of 30°-150° to each other.

[0037] Specifically, the S30 step can form a large-area uniform periodic interference light field through the synergistic effect of the coherent light source and the diffraction grating element (multi-grating structure), without the need for point-by-point scanning to adapt to large-area processing requirements and improve efficiency; the adjustable angle of 30°-150° of the plurality of square transmission gratings can not only lay a highly ordered foundation for the array structure through symmetric interference fringes, but also flexibly control the pattern morphology to break the fixed pattern limitation of traditional methods, and the non-contact exposure can avoid template contamination and wear, significantly improving process stability and adaptability.

[0038] In the S30 step, the diffraction grating element includes 3 square transmission gratings, and the 3 square transmission gratings are arranged at an angle of 120° to each other; in the exposure process of the S30 step: the exposure wavelength is 266nm, the full power of the coherent light source is 100-120mW (preferably 115mW), and the exposure time is 8-12s (preferably 10s).

[0039] Specifically, the three square transmission gratings intersecting at 120° can form a triple-symmetry periodic interference light field, laying a highly ordered foundation for the array structure; the combination of 266 nm wavelength, which is suitable for the photosensitive properties of photoresist, 100-120 mW (preferably 115 mW) power, and 8-12 s (preferably 10 s) time, which is verified by experiments, can make the cross-linking degree of the exposed area of the photoresist moderate, avoid the stripe blur caused by overexposure or underexposure, and ensure the clear pattern topography. The overall design not only realizes large-area exposure, but also solves the problems of insufficient order and poor pattern quality in existing methods, providing an accurate and stable initial pattern for subsequent processes.

[0040] Further, the number of square transmission gratings in the diffraction grating element, the exposure power of the coherent light source, and the exposure time, etc. factors will affect the final obtained pattern topography. The present application has found through experiments that when the above parameters are used, the obtained pattern topography is clear and appropriate.

[0041] S40, sequentially performing post-baking, developing and fixing treatment on the initial patterned photoresist to obtain an ordered patterned photoresist.

[0042] Specifically, in the step S40: the post-baking temperature is 70-80°C (preferably 75°C), and the post-baking time is 0.5-1.5 min (preferably 1 min); wherein, the low-temperature short-time post-baking can promote the cross-linking reaction of the exposed area of the SU-8 2000.5 negative photoresist to be completely performed - not only compensating for the possible local insufficient cross-linking problem in the exposure stage, enhancing the mechanical strength and etching resistance of the glue layer; but also avoiding the dark reaction (non-exposure cross-linking) of the unexposed area caused by high-temperature long-time baking, thus ensuring the clarity of the pattern boundary from the root, and providing a structurally stable substrate for subsequent developing and etching.

[0043] Specifically, the developing liquid used for developing is propylene glycol methyl ether acetate, and the developing time is 1-2 min (preferably 1.5 min); wherein, the developing time of 1-2 min can ensure that the unexposed soluble glue layer is completely removed, while the exposed area which has been cross-linked and hardened is not eroded; not only avoiding the unexposed residue caused by "insufficient development" (which affects the pattern accuracy), but also preventing the edge erosion of the exposed area caused by "overdevelopment" (which leads to pattern defects), thus accurately realizing the conversion from latent image to visible ordered pattern.

[0044] Specifically, the fixing liquid used for fixing is isopropyl alcohol, and the fixing time is 2-3 minutes (preferably 2 minutes). In the fixing process, the residual developer on the surface of the substrate and the adhesive layer can be quickly washed away, the developing reaction is immediately terminated, and the pattern damage caused by subsequent uncontrolled development is avoided. At the same time, isopropyl alcohol has a fast evaporation speed and high cleanliness, which can avoid water stain residue or chemical pollution, further fix the pattern shape, and ensure that the final ordered patterned photoresist has a clean surface, regular edges and complete structure.

[0045] S50, etching the substrate as a mask with the ordered patterned photoresist, removing the residual ordered patterned photoresist after etching, and finally forming a large-area highly ordered array structure on the substrate.

[0046] Specifically, the S50 step realizes multiple key benefits through the core operation of "mask etching-residual adhesive removal": using the high-definition and high-etching-resistance photoresist obtained in the S40 step as a mask, the ordered pattern can be accurately and distortion-free transferred to the substrate, ensuring the high order and complete appearance of the final array structure; the etching process simultaneously acts on the large-area photoresist pattern constructed in the previous step, naturally extending the large-area processing advantage and breaking through the small-area processing limitation; removing the residual adhesive layer after etching can obtain a clean target structure, meeting the subsequent application requirements.

[0047] Correspondingly, the application also provides a large-area highly ordered array structure prepared by any one of the above-mentioned methods for preparing a large-area highly ordered array structure; wherein the processing area size of the large-area highly ordered array structure reaches centimeter level.

[0048] Specifically, the processing area size reaches centimeter level, which can directly break through the limitation of technologies such as electron beam and focused ion beam "single processing area only tens of microns", and meet the application requirements of large-area substrate in the fields of sensing array and large-area photothermal film without small-area splicing, reducing the application integration difficulty; at the same time, the structure units in the large-area range can maintain uniform and ordered arrangement, avoiding the performance fluctuation caused by splicing, ensuring the performance stability in application, and the single processing coverage is wide, which can improve the batch production efficiency with efficient preparation process, and significantly reduce the scale application threshold of large-area ordered micro-nano structure.

[0049] The technical solutions of the application will be further described in combination with specific embodiments.

[0050] Embodiment 1: Embodiment 1 provides a large-area highly ordered array structure and a preparation method thereof, wherein the large-area highly ordered array structure is a hexagonal array structure, and the specific preparation method is as follows: Step 1: Substrate Cutting, Cleaning, Drying, and Activation: Using a 4-inch silicon wafer as the substrate, it was first cut into 2.4cm × 2.4cm squares using a laser dicing machine. Next, the cut silicon wafer was rinsed with water, then sonicated in acetone solution for 15 minutes, followed by sonication in ethanol solution for 15 minutes. Subsequently, a "piranha" solution was prepared using 30% hydrogen peroxide and 98% concentrated sulfuric acid at a volume ratio of 1:3, heated to 250°C, and used to soak the substrate for 15 minutes. Afterward, the substrate was rinsed with a large amount of ultrapure water and dried with nitrogen gas. The dried substrate was then placed in a 125°C oven for 3 hours to remove residual water. Finally, the substrate was removed, cooled to room temperature, and activated using oxygen plasma bombardment (50mW, 3 minutes).

[0051] Step 2, Photoresist Film Coating and Baking: Using a benchtop spin coater, SU-82000.5 negative photoresist was uniformly coated onto the silicon substrate surface using a spin coater. First, spin coat at 500 rad / min for 5 seconds, then at 4000 rad / min for 40 seconds. Subsequently, the substrate was baked using a small hot plate to evaporate the organic solvents in the photoresist film, first at 65°C for 60 seconds, then at 95°C for 60 seconds.

[0052] Step 3, Exposure and Patterning of Photoresist: A laser source with a wavelength of 266nm and a full power of 110mW is expanded and then irradiated onto the photoresist. Figure 2 The diffraction grating element shown includes three square transmission gratings arranged at a 120° angle to each other in space. The three first-order diffracted beams generated by the three square transmission gratings overlap on the substrate surface to record the pattern morphology information in the photoresist film, and the exposure time is controlled to 10s by an electronically controlled aperture.

[0053] Step 4, Post-baking, Development, and Fixing: Using a small hot plate, bake the exposed substrate at 75°C for 1 minute to induce the cascade reaction within the photoresist. Then, immerse the substrate in propylene glycol methyl ether acetate for 1.5 minutes to develop the pattern morphology. Next, immerse the substrate in isopropanol for 2 minutes to fix and remove residual developer and impurities. Finally, rinse the substrate with ultrapure water and dry it with nitrogen gas.

[0054] Step 5, Etching and Resin Removal: The substrate is etched using an ordered patterned photoresist as a mask (dry or wet etching). After etching, any remaining ordered patterned photoresist is removed, ultimately forming a large-area, highly ordered array structure on the substrate, such as... Figure 3 As shown. A schematic diagram and scanning electron microscope image of the pattern morphology prepared in Example 1 are shown below. Figure 4 and Figure 5 As shown.

[0055] Embodiment 2: The embodiment 2 provides a large-area highly ordered array structure and a preparation method thereof, the large-area highly ordered array structure is a fishbone-shaped array morphology structure, a structure schematic diagram and a scanning electron microscope image of the pattern morphology prepared in the embodiment 2 are as shown in Figure 6 and Figure 7 The preparation method of the large-area highly ordered array structure provided in the embodiment 2 is basically the same as the preparation method in the embodiment 1, and the difference is only in the third step: Step three, exposure and patterning of photoresist: a laser light source with a wavelength of 266 nm and a full power of 110 mW is expanded and then irradiated on the diffraction grating element (including three square transmission gratings, and the three square transmission gratings are mutually arranged at an angle of 120°) shown in Figure 2 The two first-order diffraction lights generated by the three square transmission gratings on the diffraction grating are overlapped on the substrate surface (the diffraction light of one of the square transmission gratings is shielded, and only the diffraction light generated by two square transmission gratings is used for superposition to form a pattern morphology), so as to record the pattern morphology information in the photoresist film, and the exposure time is controlled to be 10 s through the electrically controlled diaphragm.

[0056] Embodiment 3: The embodiment 3 provides a large-area highly ordered array structure and a preparation method thereof, the large-area highly ordered array structure is a rod-shaped array morphology, a structure schematic diagram and a scanning electron microscope image of the pattern morphology prepared in the embodiment 3 are as shown in Figure 8 and Figure 9 The preparation method of the large-area highly ordered array structure provided in the embodiment 3 is basically the same as the preparation method in the embodiment 1, and the difference is only in the third step: Step three, exposure and patterning of photoresist: a laser light source with a wavelength of 266 nm and a full power of 110 mW is expanded and then irradiated on the diffraction grating element (including three square transmission gratings, and the three square transmission gratings are mutually arranged at an angle of 120°) shown in Figure 2 The one first-order diffraction light generated by the three square transmission gratings on the diffraction grating is overlapped on the substrate surface (the diffraction light of two of the square transmission gratings is shielded, and only the diffraction light generated by one square transmission grating is used for superposition to form a pattern morphology), so as to record the pattern morphology information in the photoresist film, and the exposure time is controlled to be 10 s through the electrically controlled diaphragm.

[0057] Compared with the prior art, the present application has the following obvious advantages: (1) The present application records the pattern topography by irradiating ultraviolet light onto the diffraction grating element composed of multiple square transmission gratings, forming a specific pattern by interference superposition of multiple diffraction lights and transferring to the substrate coated with photoresist. Compared with the traditional method, the design can naturally obtain a unique pattern topography different from a single transmission grating, breaking through the pattern limitation of a single grating.

[0058] (2) The processing area of the present application can reach centimeter level, and the pattern has high order, which meets the demand of large-area application and guarantees the uniform stability of structural performance.

[0059] (3) The present application can change the interference superposition effect of diffraction light by adjusting the number of square transmission gratings in the diffraction grating element, and then flexibly control the pattern topography. Compared with the traditional method, this control method is more simple and flexible, and significantly improves the pattern preparation efficiency.

[0060] In summary, unlike the prior art, the present application provides a large-area highly ordered array structure and a preparation method thereof. The preparation method comprises the following steps: first, the substrate is sequentially cut, washed, dried and surface activated to obtain a pretreated substrate; second, photoresist is coated on the surface of the pretreated substrate, and the coated photoresist is subjected to preliminary baking treatment; third, the photoresist is exposed to light using a diffraction grating element combined with a coherent light source to obtain an initial patterned photoresist; the diffraction grating element comprises multiple square transmission gratings, and the multiple square transmission gratings are arranged at an angle of 30°-150° with respect to each other; fourth, the initial patterned photoresist is sequentially subjected to post-baking, development and fixing treatment to obtain an ordered patterned photoresist; and finally, the substrate is etched using the ordered patterned photoresist as a mask, and the residual ordered patterned photoresist is removed after etching, finally forming a large-area highly ordered array structure on the substrate. The preparation method of the present application uses diffraction grating interference exposure technology, which can avoid the pollution and loss of traditional templates without relying on specific templates, can realize large-area processing to break through the limitation of small-area processing, can flexibly adjust the pattern topography by adjusting parameters such as grating angle, can reduce equipment cost and process complexity, and can comprehensively solve the core defects of the prior art, and is suitable for large-scale preparation of large-area highly ordered array structure.

[0061] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own emphasis. If not fully described in individual embodiments, reference can be made to the description of other embodiments.

[0062] The above embodiments only express the implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for fabricating a large-area, highly ordered array structure, characterized in that, include: S10, the substrate is sequentially cut, cleaned, dried and surface activated to obtain a pretreated substrate; S20, photoresist is coated on the pretreated substrate surface, and the coated photoresist is subjected to preliminary baking treatment; S30, the photoresist is exposed using a diffraction grating element combined with a coherent light source to obtain an initial patterned photoresist; the diffraction grating element includes multiple square transmission gratings, and the multiple square transmission gratings are arranged in space at an angle of 30° to 150° to each other. S40, the initial patterned photoresist is sequentially subjected to post-baking, development and fixing processes to obtain an ordered patterned photoresist; S50, using the ordered patterned photoresist as a mask, the substrate is etched. After etching, the residual ordered patterned photoresist is removed, and finally a large-area highly ordered array structure is formed on the substrate.

2. The method for fabricating a large-area, highly ordered array structure according to claim 1, characterized in that, The cleaning process in step S10 includes: first, ultrasonically treating the substrate, then immersing the substrate in a "piranha" solution at 250°C, and finally drying the substrate with nitrogen gas.

3. The method for fabricating a large-area, highly ordered array structure according to claim 1, characterized in that, The surface activation treatment in step S10 includes bombarding the substrate with oxygen plasma at a power of 45~55mW for 2~4min.

4. The method for fabricating a large-area, highly ordered array structure according to claim 1, characterized in that, In step S20, the photoresist is SU-8 2000.5 negative photoresist.

5. The method for fabricating a large-area, highly ordered array structure according to claim 1, characterized in that, The step of coating the photoresist in step S20 specifically includes: first, spin coating at a speed of 400~600 rad / min for 4~6 seconds, and then spin coating at a speed of 3500~4500 rad / min for 35~45 seconds.

6. The method for fabricating a large-area, highly ordered array structure according to claim 1, characterized in that, The preliminary baking process in step S20 specifically includes: first baking the coated photoresist at 60~70℃ for 55~65s, and then baking the coated photoresist at 90~100℃ for 55~65s.

7. The method for fabricating a large-area, highly ordered array structure according to claim 1, characterized in that, In step S30: the diffraction grating element includes three square transmission gratings, and the three square transmission gratings are arranged in a spatial arrangement at an angle of 120° to each other.

8. The method for fabricating a large-area, highly ordered array structure according to claim 1, characterized in that, In the exposure process of step S30: the exposure wavelength is 266nm, the full power of the coherent light source is 100~120mW, and the exposure time is 8~12s.

9. The method for fabricating a large-area, highly ordered array structure according to claim 1, characterized in that, In step S40: the post-baking temperature is 70~80℃, and the post-baking time is 0.5~1.5min; the developing solution used is propylene glycol methyl ether acetate, and the developing time is 1~2min; the fixing solution used is isopropanol, and the fixing time is 2~3min.

10. A large-area, highly ordered array structure, characterized in that, It is prepared by the method for preparing a large-area highly ordered array structure as described in any one of claims 1 to 9; The processing area of ​​the large-area, highly ordered array structure reaches the centimeter level.

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