Preparation method of high-resolution nano-imprinting convex template
By preparing high-resolution nanoimprinting convex templates in nanoimprinting technology, the error problem caused by uneven conductive layer thickness is solved, and stable and reliable nanoimprinting template manufacturing is achieved, which improves resolution and accuracy.
Patent Information
- Application Number
- CN202510426097.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-07
- Publication Date
- 2025-06-17
AI Technical Summary
In nanoimprinting technology, the preparation of high-resolution masks involves multiple steps, and there are major challenges in maintaining high-resolution pattern transfer, especially in the case of uneven thickness of the conductive layer, resulting in the generation of errors in the electron beam during lithography.
Using a high-resolution nanoimprinted convex template preparation method, a photoresist layer is prepared in the non-functional area of the substrate, and the anti-adhesive layer and functional material are deposited under its assistance, the functional material and anti-adhesive layer in the invalid area are removed, and the protective layer is formed, and the other areas are subsequently etched to form the convex portion of the nanoimprinted template.
The structural transfer errors in traditional graphics transfer methods are effectively avoided, and the stable and reliable manufacturing of nanoimprint templates is achieved, and the resolution and accuracy are improved.
Smart Images
Figure CN120161670A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor processing, and particularly relates to a method for preparing a high-resolution nanoimprint convex template. Background Art
[0002] Micro-nano manufacturing technology is an important pillar of the modern micro-nano technology industry and the manufacturing foundation of integrated circuits, optoelectronic devices, and micro-electromechanical systems. Traditional lithography technologies such as deep ultraviolet lithography and electron beam lithography cannot achieve a balance in terms of processing resolution, processing accuracy, and processing area. Nanoimprint technology can replicate high-resolution nano-structures over a large area and greatly reduce energy consumption. It is one of the mainstream lithography technologies in the post-Moore era. The basic principle of nanoimprint technology is to use a nano-pattern template to press on a polymer for molding to achieve the processing of nano-patterns. This technology does not depend on the resolution of the optical system and can break through the optical diffraction limit.
[0003] The resolution and accuracy of the nanoimprint template play a decisive role in the resolution and accuracy of the final structure. Since the preparation of a high-resolution mask template in related technologies involves multiple steps such as lithography and pattern transfer, it still poses a major challenge to maintain high-resolution pattern transfer between multiple steps. For example, during the process of pattern transfer using electron beam etching, a conductive layer needs to be added to a quartz substrate, but it is very difficult to keep the thickness of the conductive layer consistent and precisely meet the required standard. A non-uniform conductive layer thickness will cause different electron beam propagation and interaction effects in different regions during the lithography process, resulting in errors.
[0004] Therefore, how to reduce errors during the pattern transfer process has become an urgent problem for those skilled in the art to solve. Summary of the Invention
[0005] The main object of the present invention is to propose a method for preparing a high-resolution nanoimprint convex template, aiming to prepare a nanoimprint template with low errors.
[0006] To achieve the above object, the preparation method of the high-resolution nanoimprint convex template proposed by the present invention includes the following steps: S10. Provide a substrate, the surface of the substrate includes a functional area and a non-functional area, the functional area includes an effective area and an ineffective area, process the substrate, coat a photoresist on the surface of the substrate, bake, expose, and develop to prepare a photoresist layer in the non-functional area of the substrate to obtain a first intermediate product; S20. Deposit an anti-adhesion layer and a functional material in the functional area of the first intermediate product in sequence, remove the functional material in the ineffective area of the first intermediate product, and remove the anti-adhesion layer and the photoresist layer to deposit a functional material in the effective area of the substrate to form a protective layer to obtain a second intermediate product; S30. After etching the surface of the substrate corresponding to the non-functional area and the ineffective area of the second intermediate product, etch and remove the protective layer to obtain a high-resolution nanoimprint convex template.
[0007] Optionally, in step S10, the way to process the substrate is: treat the substrate with oxygen plasma; in step S20, the way to deposit an anti-adhesion layer in the functional area of the first intermediate product is: perform gas-phase modification on the first intermediate product with a single-molecule solution to deposit a single-molecule anti-adhesion layer in the functional area of the first intermediate product; the way to remove the anti-adhesion layer is: treat the first intermediate product after removing the functional material in the ineffective area with oxygen plasma to remove the single-molecule anti-adhesion layer.
[0008] Optionally, the solute of the single-molecule solution includes at least one of hexamethyldisilazane, octadecyltrichlorosilane, trichloro(1H,1H,2H,2H-tridecafluorooctyl)silane, and n-octyltrichlorosilane; and / or, the single-molecule capacity of the single-molecule anti-adhesion layer is 1.17×10-10 μL / nm2 to 1.17×10-9 μL / nm2; and / or, the temperature of the gas-phase modification is 25°C to 300°C, and the time of the gas-phase modification is 20 min to 40 min.
[0009] Optionally, step S10 includes: S101. Provide a substrate, the surface of the substrate includes a functional area and a non-functional area, the functional area includes an effective area and an ineffective area; S102. Process the substrate; S103. Coat a negative photoresist on the surface of the substrate and bake; S104. Expose the negative photoresist in the non-functional area of the substrate; S105. Develop the negative photoresist on the substrate to prepare a photoresist layer in the non-functional area of the substrate to obtain a first intermediate product.
[0010] Optionally, in step S10, the baking temperature is 80°C to 180°C, and the baking time is 1 min to 5 min; and / or, the material of the substrate includes at least one of silicon, silicon carbide, silicon oxide, silicon nitride, quartz, diamond, and indium tin oxide; and / or, the thickness of the photoresist layer is 10 nm to 100 nm; and / or, the photoresist includes at least one of hydrogen silsesquioxane, polymethyl methacrylate, and diazonaphthoquinone-phenol resin.
[0011] Optionally, step S20 includes: S201, depositing an anti-sticking layer on the functional area of the first intermediate product; S202, depositing a functional material on the surfaces of the photoresist layer and the anti-sticking layer until the thickness of the functional material is greater than that of the photoresist layer; S203, polishing to remove the functional material above the photoresist layer until the photoresist layer is exposed; S204, covering a sticky layer on the surface of the remaining functional material, and after the functional material in the invalid area is in conformal contact with the sticky layer, peeling off the sticky layer to remove the functional material in the invalid area, and the functional material remaining on the effective area of the first intermediate product forms a protective layer; S205, removing the anti-sticking layer and etching to remove the photoresist layer to obtain a second intermediate product.
[0012] Optionally, in step S20, the functional material includes a metal material or a non-metal material. Among them, the metal material includes at least one of gold, silver, aluminum, titanium, chromium, nickel, copper, aluminum alloy, copper alloy, and nickel-chromium alloy, and the non-metal material includes at least one of aluminum oxide, silicon oxide, titanium oxide, silicon, and germanium.
[0013] Optionally, in step S20, the material of the sticky layer includes an adhesive material or a tape material. Among them, the adhesive material includes at least one of polydimethylsiloxane, polyvinyl alcohol, ultraviolet curable glue, and AB glue, and the tape material includes at least one of high-temperature tape, transparent tape, nano-tape, and thermal release tape.
[0014] Optionally, step S30 includes: S301, dry-etching the surface of the substrate corresponding to the non-functional area and the invalid area of the second intermediate product; S302, wet-etching the protective layer to remove the protective layer.
[0015] Optionally, in step S301, the dry-etching includes at least one of reactive ion beam etching, inductively coupled plasma etching, and capacitively coupled plasma etching.
[0016] The technical solution of the present invention first prepares a photoresist layer in the non-functional area of the substrate, and then deposits an anti-adhesion layer and a functional material in the non-functional area in sequence with the assistance of the photoresist layer. The anti-adhesion layer facilitates the removal of the functional material. After sequentially removing the functional material, the anti-adhesion layer, and the photoresist layer in the invalid area, the protective layer is directly attached to the effective area on the surface of the substrate. Then, etching treatment is performed on other areas, causing the surfaces of the non-functional area and the invalid area of the substrate to sink, forming the concave part of the nanoimprint template. Finally, the protective layer is removed, and the effective area protruding relative to other areas on the substrate is exposed, forming the convex part of the nanoimprint template, avoiding the structure transfer error in the traditional pattern transfer method, and thus realizing the stable and reliable manufacturing of the nanoimprint template. Description of the Drawings
[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.
[0018] Figure 1 Schematic diagram of the steps of the preparation method of the high-resolution nanoimprint convex template provided by the embodiment of the invention;
[0019] Figure 2 Preparation flow chart of the preparation method of the high-resolution nanoimprint convex template provided by the embodiment of the present invention;
[0020] Figure 3 For Figure 2 Structural schematic diagram of the first intermediate product in
[0021] Figure 4 For Figure 2 Structural schematic diagram of the second intermediate product in
[0022] Figure 5 For Figure 2 Structural schematic diagram of the high-resolution nanoimprint convex template in
[0023] Figure 6 For Figure 2 Preparation flow chart of preparing the first intermediate product from the substrate in
[0024] Figure 7 For Figure 2 Preparation flow chart of preparing the second intermediate product from the first intermediate product in
[0025] Figure 8 For Figure 2 Preparation flow chart of preparing the high-resolution nanoimprint convex template from the second intermediate product in
[0026] Figure 9 Characterization diagram of the nanoimprint convex mold plate of the comparative example of the present invention;
[0027] Figure 10 Characterization diagram of the nanoimprint convex mold plate of the embodiment of the present invention.
[0028] The realization, functional features and advantages of the object of the present invention will be further described in conjunction with the embodiments and with reference to the accompanying drawings. Detailed implementation manners
[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0030] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.
[0031] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution where A and B are satisfied simultaneously. In addition, the technical solutions between the embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.
[0032] The resolution and precision of the nanoimprint template play a decisive role in the resolution and precision of the final structure. Since the preparation of a high-resolution mask in related technologies involves multiple steps such as lithography and pattern transfer, there are still significant challenges in maintaining high-resolution pattern transfer between multiple steps. For example, during the process of pattern transfer using electron beam lithography, a conductive layer needs to be added on a quartz substrate, but it is difficult to keep the thickness of the conductive layer consistent and precisely meet the required standards. The uneven thickness of the conductive layer will cause different electron beam propagation and interaction effects in different regions during the lithography process, resulting in errors; or a metal layer is plated on the quartz substrate, a negative photoresist is coated on the surface of the metal layer and exposed and developed, and the metal layer and the substrate are etched using the developed photoresist as a mask. However, such negative photoresist is not resistant to etching, and the resolution of the final template is not high.
[0033] Based on this, the present invention provides a method for preparing a nanoimprint template. Please refer to Figure 1 , the method for preparing a nanoimprint template includes the following steps:
[0034] S10. Provide a substrate. The surface of the substrate includes a functional area and a non-functional area. The functional area includes an effective area and an invalid area. The substrate is processed, a photoresist is coated on the surface of the substrate, baked, exposed, and developed to prepare a photoresist layer in the non-functional area of the substrate, and a first intermediate product is obtained;
[0035] S20. Deposit an anti-adhesion layer and a functional material on the functional area of the first intermediate product in sequence, remove the functional material in the invalid area of the first intermediate product, and remove the anti-adhesion layer and the photoresist layer to deposit a functional material on the effective area of the substrate to form a protective layer, and a second intermediate product is obtained;
[0036] S30. After etching the surface of the substrate corresponding to the non-functional area and the invalid area of the second intermediate product, etch and remove the protective layer to obtain a nanoimprint template.
[0037] The technical solution of the present invention first prepares a photoresist layer in the non-functional area of the substrate, and then deposits an anti-adhesion layer and a functional material in the non-functional area with the assistance of the photoresist layer. The anti-adhesion layer makes the functional material easy to remove. After sequentially removing the functional material, the anti-adhesion layer, and the photoresist layer in the invalid area, the protective layer is directly attached to the effective area on the surface of the substrate. Then, the other areas are etched, so that the surfaces of the non-functional area and the invalid area of the substrate sink to form the concave part of the nanoimprint template. Finally, the protective layer is removed, and the effective area of the substrate that protrudes relative to other areas is exposed to form the convex part of the nanoimprint template, avoiding the structure transfer error in the traditional pattern transfer method, thus realizing the stable and reliable manufacturing of the nanoimprint template, and providing a new solution for the manufacturing of sub-10-nanometer half-period nanoimprint templates in fields such as semiconductor advanced node processes, optoelectronics, biology, and surface science.
[0038] Please refer to Figures 2 to 5 Figures 2 to 5
[0039] Coat a photoresist on the surface of the substrate, bake, expose, and develop it to prepare a photoresist layer in the non-functional area of the substrate, obtaining a first intermediate product;
[0040] Deposit an anti-sticking layer and a functional material in the functional area of the first intermediate product in sequence. The deposited anti-sticking layer can separate the functional material from the substrate to facilitate the subsequent peeling of the functional material. The deposited functional material adheres to the substrate surface and can prevent the corresponding area of the substrate from being etched. Since the functional material in the invalid area is at the edge of the pattern and is continuous in a large area, while the functional material in the effective area is in the gaps of the pattern area and is interspersed in the photoresist layer, the functional material in the invalid area of the first intermediate product can be removed through the above differences, while the functional material in the effective area is retained. Then, the anti-sticking layer and the photoresist layer are removed. At this time, only the effective area of the substrate is deposited with the functional material, and the functional material deposited in the effective area forms a protective layer, obtaining a second intermediate product;
[0041] Since a protective layer is formed in the effective area of the substrate of the second intermediate product, the first etching can be selectively performed on the substrate surface corresponding to the non-functional area and the invalid area of the second intermediate product during etching, so that the substrate surface corresponding to the non-functional area and the invalid area sinks towards the center of the substrate. Then, the protective layer is removed through the second etching to obtain a high-resolution nanoimprint convex template.
[0042] During the use of the nanoimprint template, that is, during the nanoimprint process, the substrate protrusion will directly contact the product coated with the imprinting glue.
[0043] Among them, the invalid area on the substrate surface corresponds to the non-graphic area of the nanoimprint template, and the effective area and the non-functional area on the substrate surface correspond to the graphic area of the nanoimprint template. Among them, the effective area corresponds to the protrusion of the nanoimprint template.
[0044] To realize the generation of the anti-sticking layer and the subsequent removal of the anti-sticking layer, the anti-sticking layer in the embodiment of the present invention is a single-molecule anti-sticking layer. Preferably, before step S10, it further includes: treating the substrate with oxygen plasma to make the substrate surface attached with hydroxyl groups. After the substrate surface is attached with hydroxyl groups, the surface energy increases, making the substrate more likely to interact with other substances.
[0045] In step S20, the method for depositing the anti-adhesion layer on the functional area of the first intermediate product is as follows: the first intermediate product is subjected to gas-phase modification using a single-molecule solution, so as to deposit a single-molecule anti-adhesion layer on the functional area of the first intermediate product. Since the surface energy increases after the substrate surface is attached with hydroxyl groups, the molecules in the single-molecule solution are more easily attracted to the substrate surface, and it helps the single molecules to form a uniform modification layer on the substrate surface, ensuring the performance consistency of the substrate surface, making the thickness of the obtained single-molecule anti-adhesion layer uniform, and thus providing stable and uniform surface properties for subsequent processes.
[0046] In step S20, the method for removing the anti-adhesion layer is as follows: the first intermediate product after removing the functional material in the ineffective removal area is treated with oxygen plasma to remove the single-molecule anti-adhesion layer. In this way, the oxygen plasma reacts with the single-molecule anti-adhesion layer to remove the single-molecule anti-adhesion layer, and the treatment conditions of the oxygen plasma can be controlled to make it react preferentially with the protective layer formed by the functional material.
[0047] Therefore, treating the substrate with oxygen plasma makes the substrate surface attached with hydroxyl groups and the surface energy increases. During gas-phase modification, the molecules in the single-molecule solution are more easily attracted to the substrate surface, and it helps the single molecules to form a uniform modification layer on the substrate surface, ensuring the performance consistency of the substrate surface. Finally, using oxygen plasma can better remove the anti-adhesion layer.
[0048] In an embodiment of the present invention, the solute of the single-molecule solution includes at least one of hexamethyldisilazane, octadecyltrichlorosilane, trichloro(1H,1H,2H,2H-tridecafluorooctyl)silane, and n-octyltrichlorosilane; the solvent is selected according to the solubility, volatility, and chemical stability of different solutes. In some specific embodiments, the solute of the single-molecule solution is octadecyltrichlorosilane, and the solvent is selected as anhydrous hexane. Using the above substances can effectively reduce the adhesion force between the substrate and the functional material, facilitating the subsequent peeling of the functional material.
[0049] In an embodiment of the present invention, the single-molecule solution is an octadecyltrichlorosilane (OTS) solution, and the molar volume of the OTS solution is 395.5 m 3 / mol, and the single-molecule capacity of the single-molecule anti-adhesion layer is 1.17×10 -10 mL / nm 2 ~1.17×10 -9 mL / nm 2 .
[0050] It should be noted that the single-molecule capacity is the volume of the single-molecule solution required for the substrate per unit area. In some specific embodiments, the specification of the substrate surface is 26 mm×33 mm, and the volume of the OTS solution with a purity of more than 90% consumed is 0.1 mL to 1 mL.
[0051] In an embodiment of the present invention, the temperature of the gas-phase modification is 25°C to 300°C, and the time of the gas-phase modification is 15 min to 40 min. Specifically, the temperature of the gas-phase modification can be 25°C, 120°C, 220°C, 300°C, etc., and the time of the gas-phase modification can be 15 min, 20 min, 30 min, 40 min, etc. The specific temperature and time of the gas-phase modification are determined according to the type of the single-molecule solution. Preferably, when the single-molecule solution is an octadecyltrichlorosilane (OTS) solution, the temperature of the gas-phase modification can be 120°C to 150°C, and the time of the gas-phase modification can be 15 min to 30 min.
[0052] Specifically, in some embodiments, the gas-phase modification of the first intermediate product using the OTS solution can be carried out by the following steps:
[0053] Place the first intermediate product and a glass petri dish containing 200 μL of OTS solution with a purity of more than 90% 5 cm apart in a 120°C vacuum oven and place for 15 min;
[0054] Take out the first intermediate product, place the first intermediate product in an acetone solution for ultrasonic cleaning for 1 min, then put it into an isopropyl alcohol solution for ultrasonic cleaning for 1 min, and finally dry it with nitrogen.
[0055] In an embodiment of the present invention, the photoresist can be selected from a positive photoresist and a negative photoresist. The positive photoresist materials include materials such as polymethyl methacrylate and diazonaphthoquinone-phenol resin, where the solubility of the photoresist in the exposure area in the developer is enhanced. The negative photoresist includes materials such as hydrogen silsesquioxane (HSQ), where the solubility of the photoresist in the exposure area in the developer is significantly reduced. In subsequent exposure, the subsequent exposure positions of the positive photoresist and the negative photoresist are different.
[0056] Please refer to Figure 6 , in an embodiment of the present invention, step S10 includes:
[0057] S101. Provide a substrate, the surface of the substrate includes a functional area and a non-functional area, and the functional area includes an effective area and an invalid area;
[0058] S102. Process the substrate;
[0059] S103. Coat a negative photoresist on the surface of the substrate and bake it;
[0060] S104. Expose the negative photoresist on the non-functional area of the substrate;
[0061] S105. Develop the unexposed negative photoresist on the substrate to prepare a photoresist layer in the non-functional area of the substrate, and obtain a first intermediate product;
[0062] Thus, by coating a negative photoresist on the substrate surface, baking, exposing, and developing, a photoresist layer is prepared. The area to be exposed is only the area of the non-functional region, corresponding to the concave portion of the nanoimprint template. Therefore, the exposure area is small, the error in the exposure process is reduced, and the resolution can be increased.
[0063] In some embodiments, the material of the substrate includes at least one of silicon, silicon carbide, silicon oxide, silicon nitride, quartz, diamond, and indium tin oxide. For example, in a specific embodiment, the substrate material is selected as quartz.
[0064] In step S102, the baking temperature is 80°C to 200°C, and the baking time is 1 to 5 minutes. Specifically, the temperatures are 80°C, 120°C, 160°C, 200°C, etc.
[0065] For example, in some embodiments, the negative photoresist uses hydrogen silsesquioxane (HSQ) photoresist. Step S102 includes the following steps: spin-coat HSQ photoresist on the substrate with a concentration of 1%. First, spin-coat at a speed of 500 r / s for 5 s, then spin-coat at a speed of 4000 r / s for 60 s, and the spin-coated thickness is 10 nm to 100 nm; finally, bake the spin-coated substrate on a 180-degree hot plate for 5 minutes.
[0066] In step S103, an electron beam exposure device can be used to expose the HSQ photoresist under the action of a 30-μm aperture with an exposure pressure of 30 KV. Specifically, an electron beam exposure device with the model Raith 150two can be used.
[0067] In step S104, the method for developing the negative photoresist on the substrate is as follows: immerse the substrate in a mixed solution of 1% NaOH and 4% NaCl for 1 minute for development; then rinse with deionized water for 1 minute and rinse with isopropyl alcohol solution for 30 s; finally, dry with nitrogen.
[0068] Please refer to Figure 7 , preferably, in an embodiment of the present invention, step S20 includes:
[0069] S201. Deposit an anti-adhesion layer on the functional region of the first intermediate product to facilitate the separation of the subsequent functional material from the substrate. Specifically, the anti-adhesion layer can be formed by gas-phase modification. It should be noted that in some embodiments, when depositing the anti-adhesion layer on the functional region of the first intermediate product, the anti-adhesion layer may be deposited on the photoresist layer at the same time. The main function of step 201 is to deposit the anti-adhesion layer on the functional region of the first intermediate product, and whether there is an anti-adhesion layer on the photoresist layer does not affect the implementation of this solution.
[0070] S202. Deposit a functional material on the surfaces of the photoresist layer and the anti-sticking layer until the thickness of the functional material is greater than that of the photoresist layer;
[0071] The thickness of the functional material refers to the distance from the surface of the functional material to the surface of the substrate. It can be understood that when depositing the functional material in the functional area of the first intermediate product, the functional material may be deposited on the photoresist layer at the same time. In this application, it is only restricted that the thickness of the functional material in the functional area is greater than that of the photoresist layer, so that the functional material fills the area of the substrate surface except the photoresist layer.
[0072] S203. Polish and remove the functional material above the photoresist layer until the photoresist layer is exposed;
[0073] It can be understood that when polishing and removing, not only the functional material above the photoresist layer is removed, but also part of the functional material in the functional area is removed. The obtained product exposes the photoresist layer and the functional area has the functional material with the same thickness as the photoresist layer.
[0074] S204. Cover the surface of the remaining functional material with a viscous layer. After the functional material in the invalid area achieves conformal contact with the viscous layer, peel off the viscous layer to remove the functional material in the invalid area, and the functional material remaining on the effective area of the first intermediate product forms a protective layer;
[0075] It can be understood that since the viscous layer achieves conformal contact with the functional material in the invalid area, when peeling off the viscous layer, the functional material in the invalid area will be peeled off accordingly, and the functional material in the effective area and the functional material in the invalid area are separated by the photoresist layer. Therefore, the functional material in the invalid area does not affect the functional material in the effective area when being peeled off.
[0076] For more convenient implementation, in some embodiments, the viscous layer can be covered on the surface of the polished product, but only the viscous layer is made to achieve conformal contact with the functional material in the invalid area. Then, when peeling off the viscous layer, the functional material in the invalid area will be peeled off with the peeling of the viscous layer, while the functional material in the effective area and the photoresist layer in the non-functional area will not be peeled off with the peeling of the viscous layer.
[0077] S205. Remove the anti-sticking layer and etch away the photoresist layer to obtain a second intermediate product. Only the effective area of the second intermediate product has a functional material forming a protective layer.
[0078] In this way, during deposition, the functional material and the photoresist layer jointly form a dense matching layer on the substrate surface. Then, through the polishing process, the photoresist layer is polished to be exposed, and the photoresist layer separates the functional material in the effective area from the functional material in the ineffective area, thus facilitating peeling. In this way, while achieving high-precision preparation of the protective layer, it is convenient to peel off the functional material in the ineffective area, and even in the preparation process of a nanoimprint template with a half-period less than 10 nm, both precision and efficiency can be taken into account.
[0079] Among them, the functional material is a material that can protect the covered substrate from being etched during substrate etching. By protecting a part of the substrate surface with the functional material, the pattern of the nanoimprint template can be obtained.
[0080] In step S203, the functional material includes a metal material or a non-metal material. Among them, the metal material includes at least one of gold, silver, aluminum, titanium, chromium, nickel, copper, aluminum alloy, copper alloy, and nickel-chromium alloy, and the non-metal material includes at least one of aluminum oxide, silicon oxide, titanium oxide, silicon, and germanium. In this embodiment, chromium is selected as the functional material for deposition, and the deposition thickness is 30 nm. The surface energy of chromium is more matched with the surface energy of common photoresists, and it can be in close contact with the photoresist layer during deposition to reduce errors. A thickness of 30 nm can ensure that chromium forms a continuous and uniform thin film on the substrate, so as to fully exert the performance advantages of chromium to protect the substrate during subsequent dry etching.
[0081] In step S204, the material of the adhesive layer includes an adhesive material or a tape material. Among them, the adhesive material includes at least one of polydimethylsiloxane, polyvinyl alcohol, ultraviolet curable glue, and AB glue, and the tape material includes at least one of high-temperature tape, transparent tape, nano tape, and thermal release tape. And the material of the adhesive layer is not limited to the above materials, as long as it can be in conformal contact with the functional material.
[0082] Please refer to Figure 8 , in an embodiment of the present invention, step S30 includes:
[0083] S301. Perform dry etching on the substrate surface corresponding to the non-functional area and the ineffective area of the second intermediate product;
[0084] Dry etching has the characteristic of strong anisotropy. During dry etching, since the effective area of the second intermediate product has a protective layer formed by the functional material, the effective area can be avoided from being etched, so as to realize only etching the substrate surface corresponding to the non-functional area and the ineffective area of the second intermediate product, while the substrate surface corresponding to the effective area with the protective layer is not affected, thereby ensuring the accuracy and perpendicularity of the etched pattern.
[0085] Among them, dry etching includes at least one of reactive ion beam etching (RIE), inductively coupled plasma etching (ICP), and capacitively coupled plasma etching (CCP); after etching, in the substrate of the second intermediate product, a height difference can be formed between the non-functional area and the invalid area and the effective area, so as to obtain a nanoimprint template with a protective layer on the substrate convex part.
[0086] S302. Perform wet etching on the protective layer to remove the protective layer and obtain a high-resolution nanoimprint convex template.
[0087] Wet etching has high selectivity and can quickly remove the protective layer without damaging the substrate and the etched pattern, so that the effective area of the high-resolution nanoimprint convex template is completely exposed to obtain a high-resolution nanoimprint convex template.
[0088] Moreover, a suitable etching solution needs to be selected for etching. In terms of the selection of the etching solution, the present application only limits that the etching solution can etch the functional material but not the substrate. In a specific embodiment, the substrate material is quartz, the functional material is chromium, and the etching solution is selected as ammonium cerium nitrate solution. After etching, the high-resolution nanoimprint convex template is ultrasonically cleaned in acetone and isopropyl alcohol solutions for 5 minutes each to remove impurities.
[0089] The technical solution of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.
[0090] In the comparative example, a layer of metal is first deposited on the substrate, and then a photoresist (positive photoresist) is spin-coated; then exposure is carried out; then chromium and quartz are etched in sequence. Due to the etching of chromium, a pattern transfer error is caused, specifically, a corresponding photoresist layer is first formed, and then the exposed part of the substrate is etched, and the photoresist layer cannot provide good protection for the chromium below it. Figure 9 It is a characterization diagram of the nanoimprint convex template. The half period is 19 nm. It can be seen that the widths of the lines in the pattern are inconsistent and the resolution is not high.
[0091] In the specific embodiment, it includes the following steps:
[0092] S101. Provide a substrate;
[0093] S102. Clean with oxygen plasma for 1 minute
[0094] S103. Spin-coat HSQ photoresist on the substrate with a concentration of 1%. First, spin-coat at a speed of 500 r / s for 5 s, then spin-coat at a speed of 4000 r / s for 60 s, and the spin-coating thickness is 10 nm to 100 nm; finally, bake the spin-coated substrate on a hot plate at 180 degrees for 5 minutes;
[0095] S104. Use the electron beam exposure equipment with the model of Raith 150two, namely Raith 150two, to expose the HSQ photoresist under the action of a 30μm aperture diaphragm with an exposure pressure of 30KV.
[0096] S105. Immerse the substrate in a mixed solution of 1% NaOH and 4% NaCl for 1 minute for development; then rinse with deionized water for 1 minute and rinse with isopropyl alcohol solution for 30 seconds; finally, dry with nitrogen.
[0097] S201. Place the developed sample in a vacuum oven at 120 degrees, place a glass petri dish near the substrate at a distance of 5 cm, and drop 200 μL of OTS solution into the petri dish; after evacuating for 2 minutes, turn off the vacuum pump; after modification for 15 minutes, take out the silicon substrate, then ultrasonically clean it in acetone solution for 1 minute, ultrasonically clean it in isopropyl alcohol solution for 1 minute, and dry it with nitrogen to form an OTS monolayer anti-sticking layer.
[0098] S202. Deposit chromium metal on the sample by ion beam sputtering with a deposition thickness of 30 nm.
[0099] S203. Polish the sample by ion beam polishing until the chromium metal structure on the top of the HSQ is completely removed.
[0100] S204. Cover the remaining chromium surface with tape; after the chromium in the invalid area is in conformal contact with the tape, peel off the tape to remove the chromium in the invalid area, and the chromium remaining on the effective area of the first intermediate product forms a protective layer.
[0101] S205. Treat it in an oxygen plasma environment for 10 seconds to remove the OTS monolayer anti-sticking layer.
[0102] S301. Etch the quartz substrate by ICP for 1 minute.
[0103] S302. Use a chromium etchant to remove the remaining chromium metal, ultrasonically clean it in acetone and isopropyl alcohol solutions for 5 minutes respectively to remove impurities, and obtain a high-resolution nanoimprint convex template.
[0104] Figure 10 It is a characterization diagram of the high-resolution nanoimprint convex template, with a half-period of 13 nm. It can be seen that the width of the lines in the pattern approaches uniformity and the resolution is relatively high.
[0105] The above is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.
Claims
1. A method for preparing a high-resolution nanoimprint convex template, characterized in that: The preparation method comprises the following steps: S10, providing a substrate, wherein the surface of the substrate includes a functional area and a non-functional area, wherein the functional area includes an effective area and an ineffective area, coating a photoresist on the surface of the substrate, baking, exposing, and developing to prepare a photoresist layer in the non-functional area of the substrate, and obtaining a first intermediate product; S20, sequentially depositing an anti-sticking layer and a functional material in the functional area of the first intermediate product, removing the functional material in the invalid area of the first intermediate product, and removing the anti-sticking layer and the photoresist layer, so as to deposit a functional material in the effective area of the substrate to form a protective layer, thereby obtaining a second intermediate product; S30, after etching the substrate surface corresponding to the non-functional area and the invalid area in the second intermediate product, the protective layer is removed by etching to obtain a high-resolution nanoimprint convex template.
2. The method for preparing a high-resolution nanoimprint convex template according to claim 1, characterized in that: Before step S10, the method further includes the following steps: treating the substrate with oxygen plasma; In step S20, the method of depositing the anti-adhesive layer on the functional area of the first intermediate product is: using a monomolecular solution to perform gas phase modification on the first intermediate product to deposit a monomolecular anti-adhesive layer on the functional area of the first intermediate product; The method for removing the anti-sticking layer is: the first intermediate product after removing the functional material in the invalid area is treated with oxygen plasma to remove the monomolecular anti-sticking layer.
3. The method for preparing a high-resolution nanoimprint convex template according to claim 2, characterized in that: The solute of the monomolecular solution includes at least one of hexamethyldisilazane, octadecyltrichlorosilane, trichloro(1H,1H,2H,2H-tridecafluoro-n-octyl)silane and n-octyltrichlorosilane; and / or, The monomolecular capacity of the monomolecular anti-adhesive layer is 1.17×10 -10 μL / nm 2 ~1.17×10 -9 μL / nm 2 and / or, The temperature of the gas phase modification is 25° C. to 300° C., and the time of the gas phase modification is 20 min to 40 min.
4. The method for preparing a high-resolution nanoimprint convex template according to claim 1, characterized in that: Step S10 includes: S101, providing a substrate, wherein the surface of the substrate includes a functional area and a non-functional area, and the functional area includes an effective area and an ineffective area; S102, processing the substrate; S103, coating a negative photoresist on the surface of the substrate and baking; S104, exposing the negative photoresist in the non-functional area on the substrate; S105 , developing the negative photoresist on the substrate to prepare a photoresist layer in the non-functional area of the substrate to obtain a first intermediate product.
5. The method for preparing a high-resolution nanoimprint convex template according to claim 1, characterized in that: In step S10: The baking temperature is 80° C. to 180° C., and the baking time is 1 min to 5 min; and / or, The material of the substrate includes at least one of silicon, silicon carbide, silicon oxide, silicon nitride, quartz, diamond and indium tin oxide; and / or, The thickness of the photoresist layer is 10 nm to 100 nm; and / or, The photoresist includes at least one of hydrogen silsesquioxane, polymethyl methacrylate and diazonaphthoquinone-phenolic resin.
6. The method for preparing a high-resolution nanoimprint convex template according to claim 1, characterized in that: Step S20 includes: S201, depositing an anti-sticking layer on the functional area of the first intermediate product; S202, depositing a functional material on the surface of the photoresist layer and the anti-sticking layer until the thickness of the functional material is greater than the thickness of the photoresist layer; S203, polishing and removing the functional material above the photoresist layer until the photoresist layer is exposed; S204, covering the surface of the remaining functional material with an adhesive layer, and after the functional material in the ineffective area is in conformal contact with the adhesive layer, peeling off the adhesive layer to remove the functional material in the ineffective area, and the functional material remaining on the effective area of the first intermediate product forms a protective layer; S205, removing the anti-sticking layer and etching to remove the photoresist layer to obtain a second intermediate product.
7. The method for preparing a high-resolution nanoimprint convex template according to claim 1 or 6, characterized in that: In step S20, The functional material includes a metal material or a non-metal material, wherein the metal material includes at least one of gold, silver, aluminum, titanium, chromium, nickel, copper, aluminum alloy, copper alloy and nickel-chromium alloy, and the non-metal material includes at least one of aluminum oxide, silicon oxide, titanium oxide, silicon and germanium.
8. The method for preparing a high-resolution nanoimprint convex template according to claim 6, characterized in that: In step S20, the material of the adhesive layer includes an adhesive material or a tape material, wherein the adhesive material includes at least one of polydimethylsiloxane, polyvinyl alcohol, UV curing glue, and AB glue, and the tape material includes at least one of high temperature tape, transparent tape, nano tape, and thermal release tape.
9. The method for preparing a high-resolution nanoimprint convex template according to claim 1, characterized in that: Step S30 includes: S301, dry etching the substrate surface corresponding to the non-functional area and the invalid area in the second intermediate product; S302, wet-etching the protective layer to remove the protective layer and obtain a high-resolution nanoimprint convex template.
10. The method for preparing a high-resolution nanoimprint convex template according to claim 9, characterized in that: In step S301, the dry etching includes at least one of reactive ion beam etching, inductively coupled plasma etching and capacitive plasma etching.