Nanoimprint mold and preparation method thereof

Abstract

The invention discloses a nanoimprint mold and a preparation method thereof, and relates to the technical field of nanoimprint. The preparation method of the nanoimprint mold comprises the following steps: providing a substrate; forming an imprint pattern on the surface of the substrate through first graphical etching; and masking the imprint pattern, and carrying out second graphical etching on the exposed substrate area around the imprint pattern to form an isolation groove, so that the area where the imprint pattern is located protrudes relative to the isolation groove to form an imprint boss. According to the preparation method of the nanoimprint mold, the boss structure can be prepared on the surface of the mold, the area outside the pattern mother set is effectively prevented from being alternately contacted in the imprint process, the imprint progress is accelerated, and the preparation method is suitable for a high-precision repeated stepping type imprint process.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nanoimprint technology, in particular to a nanoimprint mold and a preparation method thereof. BACKGROUND

[0002] Nanoimprint lithography technology realizes pattern transfer of micro-nano structure through direct contact between mold and substrate, and is usually applied in the fields of mask manufacturing, optical element and semiconductor device production. As a core component of the technology, the existing nanoimprint mold is usually a planar structure with a specific pattern, which completes single pattern replication through overall pressing.

[0003] However, when performing repeated step-by-step imprinting process of multiple and closely arranged same patterns on a substrate, since the pattern master of the nanoimprint mold is located on a plane, the entire surface contacts the imprinting glue layer during imprinting, and the squeezed glue inevitably spreads to the blank area outside the pattern master and adheres thereto. In the continuous imprinting process, the nanoimprint mold is easy to carry residual glue and contaminate the glue layer of this time imprinting, which causes impurities to mix into the pattern interface, defects to be formed or the thickness of the glue layer to be uneven, thereby reducing the imprinting precision and the efficiency of step-by-step repeated imprinting. SUMMARY

[0004] The purpose of the present application is to provide a nanoimprint mold and a preparation method thereof, which can effectively avoid alternating contact with the area outside the pattern master during the imprinting process through the boss structure on the surface of the mold, thereby improving the imprinting progress and being suitable for high-precision repeated step-by-step imprinting process.

[0005] The embodiments of the present application are implemented as follows: In one aspect of the present application, a preparation method of a nanoimprint mold is provided, which comprises: providing a substrate; forming an imprinting pattern on the surface of the substrate through first patterned etching; masking the imprinting pattern and performing second patterned etching on the exposed substrate area around the imprinting pattern to form an isolation groove, so that the area where the imprinting pattern is located is raised relative to the isolation groove, forming an imprinting boss.

[0006] Optionally, forming an imprinting pattern on the surface of the substrate through first patterned etching comprises: forming a first patterned mask on the surface of the substrate; etching the substrate with the first patterned mask as a mask to form the imprinting pattern.

[0007] Optionally, forming a first patterned mask on the surface of the substrate comprises: coating a first photoresist layer on the surface of the substrate; and exposing and developing the first photoresist layer to form the first patterned mask.

[0008] Optionally, after etching the substrate with the first patterned mask as a mask, the method further comprises: removing the first patterned mask.

[0009] Optionally, the imprint pattern is masked, and a second time of patterned etching is performed on the exposed substrate region around the imprint pattern, comprising: forming a second time of patterned mask on the substrate surface with the imprint pattern; etching the substrate with the second time of patterned mask as a mask to form the isolation groove; and removing the second time of patterned mask.

[0010] Optionally, the second time of patterned mask is formed on the substrate surface with the imprint pattern, comprising: coating a second photoresist layer on the substrate surface with the imprint pattern; and exposing and developing the second photoresist layer to form the second time of patterned mask.

[0011] Optionally, in the exposing and developing of the first photoresist layer, the exposing is performed by using an electron beam.

[0012] Optionally, in the exposing and developing of the second photoresist layer, the exposing is performed by using an electron beam.

[0013] Optionally, the substrate is a quartz substrate.

[0014] In another aspect of the present application, a nano-imprint mold is provided, which is prepared by the preparation method of the nano-imprint mold, comprising a substrate, the substrate having an imprint boss with an imprint pattern on the top surface of the imprint boss, and the isolation groove being arranged around the periphery of the imprint boss; and in the height direction, the groove bottom surface of the isolation groove is lower than the top surface of the imprint boss.

[0015] The present application has the following advantages: The present application provides a preparation method of a nano-imprint mold, comprising: providing a substrate; forming an imprint pattern on the surface of the substrate by a first time of patterned etching, which omits the intermediate link of first preparing a master and then re-printing in the traditional process, thereby avoiding the error introduced by multiple times of transfer, significantly improving the precision of the prepared nano-imprint mold and reducing the manufacturing cost; masking the imprint pattern, and performing a second time of patterned etching on the exposed substrate region around the imprint pattern to form an isolation groove, so that the region where the imprint pattern is located is protruding relative to the isolation groove, forming an imprint boss, and the integrated structure of the imprint boss and the isolation groove ensures that the gel only contacts the imprint boss where the imprint pattern is located during single imprinting, and the groove bottom of the isolation groove does not contact the excess gel, effectively avoiding the pollution of residual gel to the adjacent region during the process of step-by-step repeated imprinting; and only the imprint boss contacts the gel layer, while the other planar regions of the nano-imprint mold do not contact the previous pattern region which has been solidified, completely eliminating mechanical interference and ensuring the alignment accuracy and pattern integrity between multiple times of imprinting. The preparation method of the nano-imprint mold can prepare a boss structure on the surface of the mold, effectively avoid the alternating contact with the regions other than the pattern master during imprinting, improve the imprinting progress, and is suitable for high-precision repeated step-by-step imprinting process. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be considered as a limitation to the scope. Other related drawings can also be obtained by those of ordinary skill in the art without any creative effort, based on the drawings.

[0017] Figure 1 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 2 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 3 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 4 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 5 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 6 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 7 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 8 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 9 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 10 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 11 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application; Figure 12 One of the flowcharts of the preparation method of the nanoimprint mold provided by the embodiments of the present application.

[0018] Figure legend: 100-nanoimprint mold; 110-substrate; 121-first photoresist layer; 122-first patterned mask; 131-second photoresist layer; 132-second patterned mask; 140-isolation groove; 150-imprint boss; 151-imprint pattern. DETAILED DESCRIPTION

[0019] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application but not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present application.

[0021] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0022] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0023] Please refer to Figure 1 In one aspect of the embodiments of the present application, a preparation method of a nanoimprint mold 100 is provided, which specifically comprises the following steps: Step S100, providing a substrate 110; from the perspective of universality, as long as the material can meet the molding requirements of subsequent patterning etching, and has structural strength and stability to support the imprint process, it can be used as the substrate 110 in this step. Considering the requirements of precision and thermal stability of the nanoimprint process, preferably, the substrate 110 in this step is selected from a quartz substrate 110. In addition to the quartz substrate 110, in the actual production of the mask plate, there will be some blank substrates 110 that have not been patterned. In order to realize the recycling of production resources and cost optimization, the present preparation method can directly use such blank substrates 110, and especially preferentially select the 6025 standard specification mask plate blank substrate 110 commonly used in the industry.

[0024] By selecting the blank substrate 110 as the substrate 110 of the present preparation method, not only the original production waste can be converted into effective production materials, greatly reducing the raw material procurement cost, but also the standardization of the nano-imprint mold 100 manufacturing process and the finished product size can be realized by relying on the mature size specifications of the 6025 standard mask.

[0025] It should be noted that according to the difference of actual application scene, for example, different fields have different requirements for the precision, cost budget or adaptive process of the nano-imprint mold 100, the substrate 110 material can also be expanded to metal, ceramic, glass or organic polymer materials with integrated structure forming capability, and the shape of the substrate 110 is not limited in the present application, as long as the imprinting boss 150 and the isolation groove 140 can be stably formed by subsequent etching process.

[0026] After the provision of the substrate 110 in step S100, the preparation method further comprises step S200 of forming an imprinting pattern 151 on the surface of the substrate 110 by first patterning etching. The core purpose of this step is to build the imprinting pattern 151 used for subsequent imprinting pattern transfer on the surface of the substrate 110, that is, the micro-nano structure finally copied to the mask, wafer and other target substrates is based on the imprinting pattern 151 formed in this step, therefore the precision of this step directly determines the quality of the subsequent imprinting product.

[0027] In this step, the first patterning etching is to leave a pre-set pattern on the substrate 110 by selective etching, that is, to protect the area of the substrate 110 where the pattern needs to be reserved, and only etch away the area that does not need to be reserved, so as to form a protruding or recessed imprinting structure. In order to ensure the accuracy and integrity of the pattern during etching, preferably, the step is realized by mask-assisted etching.

[0028] Specifically, as shown in Figure 2 the imprinting pattern 151 is formed on the surface of the substrate 110 by first patterning etching, comprising: Step S210, as shown in Figure 9 a first patterning mask 122 is formed on the surface of the substrate 110; the first patterning mask 122 can accurately define the pattern area that needs to be reserved, avoid damage to the target pattern area during etching, and improve the etching precision of the imprinting pattern 151; at the same time, through the definition of the pattern of the first patterning mask 122, different sizes and shapes of the imprinting pattern 151 can be flexibly adapted, greatly improving the flexibility and adaptability of the preparation process.

[0029] Step S220, as shown in Figure 10As shown, the substrate 110 is etched using the first patterning mask 122 as a mask to form an imprint pattern 151. Since the covered area of ​​the first patterning mask 122 completely isolates the etching process, while the uncovered area is uniformly etched, the resulting imprint pattern 151 has better depth consistency. This avoids problems such as incomplete adhesive layer filling and unclear pattern transfer during subsequent imprinting due to uneven depth, further improving the etching accuracy of the imprint pattern 151.

[0030] Furthermore, such as Figure 3 As shown, step S210, forming a first patterned mask 122 on the surface of the substrate 110, can be achieved through the following steps: Step S211: Coat the surface of the substrate 110 with a first photoresist layer 121; Step S212: Expose and develop the first photoresist layer 121 to form the first patterned mask 122.

[0031] Specifically, such as Figure 8 As shown, to form a first patterning mask 122 on the surface of substrate 110, a first photoresist layer 121 needs to be coated on the surface of substrate 110 first. This forms a layer on the surface of substrate 110 that can undergo chemical changes through the action of a light beam or electron beam, preparing for subsequent patterning. If the thickness of the first photoresist layer 121 is uneven, it will lead to inconsistent energy absorption during subsequent exposure, resulting in blurred edges and dimensional deviations in the developed pattern. Therefore, to ensure the accuracy of subsequent exposure and development, a spin coating process is usually used. By controlling the spin coating speed and time, the first photoresist layer 121 is made into a thin film layer of uniform thickness on the surface of substrate 110.

[0032] The first photoresist layer 121 is then exposed and developed to form the first patterned mask 122. The exposure process involves irradiating the photoresist with a beam of light or electron beam of specific energy, causing a chemical change in the irradiated area of ​​the first photoresist layer 121, thereby altering its solubility in the developer. Considering the nanometer-level precision requirements for patterns in applications such as photomasks and semiconductor devices, electron beam exposure technology is preferentially selected in a preferred embodiment of this application. Compared to traditional deep ultraviolet exposure, electron beam exposure has a smaller spot size, reaching the nanometer level, and offers more precise energy control, enabling the depiction of finer pattern structures, fully meeting the requirements of high-precision imprinted patterns 151. Of course, if the application scenario has relatively lower precision requirements, such as micrometer-level imprinted patterns 151, deep ultraviolet exposure or other methods can also be used to balance cost and efficiency.

[0033] After exposure, the substrate 110 is placed in the corresponding developer for development. The photoresist areas that have not undergone chemical changes are dissolved and removed by the developer, while the areas that have changed are retained. Finally, a first patterned mask 122 that is completely consistent with the target imprint pattern 151 is formed on the surface of the substrate 110.

[0034] After forming the first patterned mask 122, in step S220, the substrate 110 is etched using the first patterned mask 122 as a mask. Dry etching is preferably employed. Dry etching utilizes active particles such as plasma to chemically react with the substrate 110 material, achieving selective removal of areas not covered by the mask. Its advantage lies in its good anisotropy, i.e., etching mainly occurs along the direction perpendicular to the surface of the substrate 110. This effectively avoids the side etching problems that may occur with wet etching, ensuring the perpendicularity of the sidewalls of the imprinted pattern 151, thereby improving the accuracy of the imprinted pattern 151.

[0035] Optionally, such as Figure 4 As shown, after etching the substrate 110 using the first patterned mask 122 as a mask in step S220, the method further includes step S230: removing the first patterned mask 122 to prevent the first patterned mask 122 from interfering with subsequent processes.

[0036] Specifically, the method for removing the first patterned mask 122 needs to be selected based on the characteristics of the material of the first patterned mask 122 and the material of the substrate 110. One removal method is plasma ashing, which generates plasma under the action of a high-frequency electric field by introducing reactive gases such as oxygen. The active particles in the plasma react chemically with the first patterned mask 122, decomposing it into volatile gases such as carbon dioxide and water, thereby achieving residue-free removal. This method can protect the substrate 110 while ensuring the cleanliness of the surface of the imprinted pattern 151. Another removal method is wet stripping, which uses a special stripping liquid, such as an organic solvent or an alkaline solution, to dissolve the first patterned mask 122. The first patterned mask 122 is then removed by cleaning and drying. This method is simple to operate and has a low cost, making it suitable for applications where the substrate 110 material is chemically resistant and the imprinted pattern 151 is large.

[0037] After the imprinted pattern 151 is formed and the first patterned mask 122 is removed, step S300 can be performed to mask the imprinted pattern 151 and perform a second patterned etching on the exposed substrate 110 area around the imprinted pattern 151 to form an isolation trench 140, so that the area where the imprinted pattern 151 is located protrudes relative to the isolation trench 140 to form an imprinted boss 150.

[0038] In the process of mask production and other processes that need to be repeated by nano-imprint mold 100, it is often necessary to continuously copy multiple identical patterns on the same substrate 110, and the cooperation of the imprinting boss 150 and the isolation groove 140 can avoid the contamination of the adhesive layer between adjacent patterns. This step forms an isolation groove 140 by etching, so that the area where the imprinting pattern 151 is located is raised relative to the isolation groove 140, forming an independent imprinting boss 150. Through the cooperation of the imprinting boss 150 and the isolation groove 140, the residual adhesive pollution of the adjacent area is effectively avoided; and only the imprinting boss 150 is in contact with the adhesive layer, and the other flat areas of the nano-imprint mold 100 are not in contact with the previously formed pattern area, which completely eliminates mechanical interference and ensures the alignment accuracy and pattern integrity between multiple imprinting. Preferably, this step also uses a mask-assisted etching method.

[0039] Specifically, as shown in Figure 5 Step S300, the imprinting pattern 151 is masked, and the second patterning etching is performed on the exposed substrate 110 area around the imprinting pattern 151, including: Step S310, as shown in Figure 12 The second patterning mask 132 is formed on the surface of the substrate 110 where the imprinting pattern 151 is formed; compared with the function of the first patterning mask 122 for defining the imprinting pattern 151, the second patterning mask 132 is used to protect the formed imprinting pattern 151. The second patterning mask 132 precisely covers the area of the imprinting pattern 151, and only exposes the substrate 110 area that needs to be etched around, to define the accurate etching area for the subsequent etching of the isolation groove 140.

[0040] Step S320, etching the substrate 110 with the second patterning mask 132 as a mask to form the isolation groove 140; due to the shielding of the second patterning mask 132, the imprinting pattern 151 will not be damaged during etching, but the exposed substrate 110 area of the second patterning mask 132 will be removed, forming the isolation groove 140 around the imprinting pattern 151. Wherein, the depth and width of the isolation groove 140 are not limited by the present application, and can be flexibly adjusted according to actual needs, as long as the imprinting boss 150 with sufficient raised height and complete edge isolation of the imprinting pattern 151 area is formed.

[0041] Preferably, the etching of the substrate 110 adopts dry etching. Wherein, the dry etching can select different etching gases according to the specific material of the substrate 110. For example, quartz substrate 110 preferentially selects fluorine-containing gas, which reacts with quartz to generate volatile silicon tetrafluoride.

[0042] After the isolation groove 140 is formed, the second patterned mask 132 needs to be removed by step S330 to expose the complete and integrally formed nanoimprint mold 100, as shown in Figure 7 to avoid the residual second patterned mask 132 affecting the subsequent process or the imprint effect.

[0043] From the implementation point of view, the removal method needs to be selected according to the type of the second photoresist layer 131 and the characteristics of the substrate 110 to not damage the structure of the imprint boss 150 and the isolation groove 140. If the substrate 110 is quartz and the second photoresist layer 131 is organic glue, the plasma ashing method is preferred for removal: oxygen plasma is introduced to decompose the organic glue into volatile gases such as carbon dioxide, without contact and liquid residue, which can ensure the cleanliness of the boss surface and avoid water accumulation or residue in the isolation groove 140 that may be caused by wet processing; if the substrate 110 is metal or ceramic, the wet stripping method can be selected: a weak alkaline stripping solution is selected to soak the substrate 110, so that the second patterned mask 132 swells and falls off, and then deionized water is used for cleaning and nitrogen is used for drying. This method is simple and low in cost.

[0044] Further, as shown in Figure 6 step S310, forming the second patterned mask 132 on the surface of the substrate 110 having the imprint pattern 151 includes: As shown in Figure 11 step S311, coating the second photoresist layer 131 on the surface of the substrate 110 having the imprint pattern 151; if the thickness of the second photoresist layer 131 is uneven, it will cause inconsistent energy absorption during subsequent exposure, resulting in uneven thickness of the second patterned mask 132, which affects the uniformity of the depth of the isolation groove 140. Therefore, the coating process usually adopts a spin coating process. By controlling the spin coating speed and time, the second photoresist layer 131 forms a thin film layer with uniform thickness on the surface of the substrate 110.

[0045] Step S312, exposing and developing the second photoresist layer 131 to form the second patterned mask 132, as shown in Figure 12 The essence is to remove the second photoresist around the imprint pattern 151 by exposure and development, and only keep the glue layer covering the imprint pattern 151 to ensure that the second patterned mask 132 can protect the imprint pattern 151 during the subsequent etching process to avoid etching the imprint pattern 151.

[0046] The exposure process is to irradiate the photoresist with a light beam or electron beam of a specific energy, so that the second photoresist layer 131 in the irradiated area undergoes a chemical change, thereby changing its solubility in the developing solution. Considering the nanometer-level requirement for pattern accuracy in scenarios such as mask plates and semiconductor devices, in a preferred embodiment of the present application, the exposure method preferentially selects electron beam exposure technology. Compared with traditional deep ultraviolet exposure, electron beam exposure has smaller spot size, which can reach nanometer level, and more precise energy control; of course, if the application scenario has relatively low precision requirement, deep ultraviolet exposure and other methods can also be selected to balance cost and efficiency.

[0047] After development, cleaning and drying are required to remove residual developing solution and ensure the structural stability of the second patterned mask 132.

[0048] Another aspect of the embodiments of the present application, as shown in Figure 7 The present application provides a nanoimprint mold 100 prepared by the preparation method of the nanoimprint mold 100 described above, which comprises a substrate 110, the substrate 110 has an imprint boss 150, the top surface of the imprint boss 150 has an imprint pattern 151; the periphery of the imprint boss 150 is provided with an isolation groove 140; along the height direction, the groove bottom surface of the isolation groove 140 is lower than the top surface of the imprint boss 150.

[0049] The preparation method of the nanoimprint mold 100 and its advantages have been described in detail above, and will not be repeated here. Preferably, the nanoimprint mold 100 is an integrated structure, that is, the imprint boss 150, the isolation groove 140 and the substrate 110 are processed and formed from the same base material, without the need for replication from a master or multi-component splicing. Compared with the split type imprint mold of the prior art, the mold with the integrated structure of the present application can not only improve the structural stability and service life, avoid the risk of falling off due to insufficient interlayer bonding force of the split type structure, but also reduce the dimensional error caused by multi-component splicing, and improve the imprint precision.

[0050] The integrated structure of the imprint boss 150 and the isolation groove 140 of the nanoimprint mold 100 described above ensures that the gel only contacts the imprint boss 150 where the imprint pattern 151 is located during single imprinting, and the groove bottom of the isolation groove 140 does not contact the excess gel. In the process of step-by-step repeated imprinting, residual gel pollution of adjacent areas is effectively avoided; only the imprint boss 150 contacts the gel layer, and other planar areas of the nanoimprint mold 100 do not contact the previously patterned areas that have been solidified, completely eliminating mechanical interference and ensuring the alignment accuracy and pattern integrity between multiple imprintings. The nanoimprint mold 100 described above can effectively avoid alternating contact with areas other than the pattern master during imprinting, improve the imprinting progress, and is suitable for high-precision repeated step-by-step imprinting process.

[0051] The above merely describes optional embodiments of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the protection scope of the present application.

[0052] In addition, it should be noted that various specific technical features described in the foregoing embodiments can be combined in any suitable manner without contradiction, and in order to avoid unnecessary repetition, various possible combinations are not described again in the present application.

Claims

1. A method for preparing a nanoimprint mold, characterized in that, include: Provide substrate; An imprint pattern is formed on the surface of the substrate by a first patterning etching. The embossed pattern is masked, and a second patterning etching is performed on the exposed substrate area around the embossed pattern to form an isolation groove, so that the area where the embossed pattern is located protrudes relative to the isolation groove, forming an embossed boss.

2. The method for preparing a nanoimprint mold according to claim 1, characterized in that, The process of forming an imprint pattern on the surface of the substrate by a first patterning etching includes: A first patterned mask is formed on the surface of the substrate; Using the first patterned mask as a mask, the substrate is etched to form the imprinted pattern.

3. The method for preparing a nanoimprint mold according to claim 2, characterized in that, The process of forming a first patterned mask on the surface of the substrate includes: A first photoresist layer is coated on the surface of the substrate; The first photoresist layer is exposed and developed to form the first patterned mask.

4. The method for preparing a nanoimprint mold according to claim 2 or 3, characterized in that, After etching the substrate using the first patterned mask as a mask, the method further includes: Remove the first graphical mask.

5. The method for preparing a nanoimprint mold according to claim 1, characterized in that, The process of masking the imprinted pattern and performing a second patterning etching on the exposed substrate area surrounding the imprinted pattern includes: A second patterned mask is formed on the surface of the substrate on which the embossed pattern is formed; Using the second patterned mask as a mask, the substrate is etched to form the isolation trench; Remove the second patterned mask.

6. The method for preparing a nanoimprint mold according to claim 5, characterized in that, The step of forming a second patterned mask on the surface of the substrate on which the imprinted pattern is formed includes: A second photoresist layer is coated on the surface of the substrate on which the imprinted pattern is formed; The second photoresist layer is exposed and developed to form the second patterned mask.

7. The method for preparing a nanoimprint mold according to claim 3, characterized in that, In the exposure and development of the first photoresist layer, the exposure is performed using an electron beam.

8. The method for preparing a nanoimprint mold according to claim 6, characterized in that, In the exposure and development of the second photoresist layer, the exposure is performed using an electron beam.

9. The method for preparing a nanoimprint mold according to claim 8, characterized in that, The substrate is a quartz substrate.

10. A nanoimprint mold, prepared by the method for preparing a nanoimprint mold according to any one of claims 1-9, characterized in that, The device includes a substrate having an embossed protrusion, the top surface of which has an embossed pattern; an isolation groove is provided around the periphery of the embossed protrusion; and along the height direction, the bottom surface of the isolation groove is lower than the top surface of the embossed protrusion.

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