Method and apparatus for fabricating three-dimensional micro / nano structures based on surface plasmon grayscale lithography system

Abstract

This application discloses a method and apparatus for manufacturing three-dimensional micro / nano structures based on a surface plasmon grayscale lithography system, relating to the field of semiconductor manufacturing. The method includes: acquiring the spatial distribution characteristics of the field intensity at the opening of a bow-shaped nanopore in the surface plasmon grayscale lithography system; determining the correspondence between the spatial distribution characteristics and the gap size of the bow-shaped nanopore based on the spatial distribution characteristics; adjusting the exposure dose of the surface plasmon grayscale lithography system to grayscale based on the correspondence between the spatial distribution characteristics and the gap size to determine the grayscale exposure input pattern corresponding to the target three-dimensional micro / nano structure; inputting the grayscale exposure input pattern into the lithography imaging model and photoresist imaging model of the surface plasmon grayscale lithography system for exposure processing to determine the pattern quality parameters corresponding to the exposed pattern. This method can greatly improve the exposure quality of the three-dimensional micro / nano structure and has significant practical applicability.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing, and in particular to a method and apparatus for manufacturing three-dimensional micro / nano structures based on a surface plasmonic grayscale lithography system. Background Technology

[0002] Various micro-nano devices fabricated based on three-dimensional micro-nano structures have higher integration and better electrical, optical, magnetic and mechanical properties, enabling them to achieve application functions that planar two-dimensional micro-nano devices cannot obtain. Therefore, they are in high demand in fields including integrated circuits, nano-optics, micro-nano electromechanical systems and biomimetic technology.

[0003] Currently, the main methods for fabricating three-dimensional micro / nano structures include electron beam lithography (EBL), focused ion beam (FIB) milling, interference lithography, laser three-dimensional direct writing, and grayscale lithography. Among these, electron beam lithography, due to its high resolution and long depth of focus, can fabricate micro / nano structures with feature sizes within 10 nanometers (nm). However, its lithographic efficiency is too low, making it unsuitable for mass industrial production. While focused ion beam lithography offers high resolution and exposure efficiency, the edges of the exposed patterns become increasingly rough with minimal increases in exposure efficiency, severely limiting the functionality of three-dimensional micro / nano devices. Interference lithography has certain advantages in fabricating large-area, high-resolution micro / nano structures, but the difficulty in controlling the relative intensity and phase of interference fringes, along with significant high-frequency information loss, severely limits the exposure quality of three-dimensional structures. Laser three-dimensional direct writing requires extremely complex and expensive equipment, and its low scanning efficiency makes it unsuitable for large-scale fabrication of three-dimensional micro / nano structures.

[0004] Compared to other three-dimensional micro / nano fabrication technologies, grayscale lithography offers numerous advantages. Surface plasmon lithography (SPL) is a nano-optical lithography technique capable of breaking the diffraction limit. It primarily utilizes bowtie nanoaperture (BAN) structures. Under ultraviolet light exposure, surface plasmon polaritons (SPPs) and quasi-spherical waves (QSWs) diffraction fields are generated at the BAN openings, transferring the exposed pattern to the photoresist (PR) to achieve super-resolution imaging. As a high-resolution, low-cost nanofabrication technology, SPL has been proven to achieve resolutions below 10 nanometers (nm). Due to its excellent controllability and scalability of nanoscale feature sizes, it has successfully produced various surface micro / nano structures. However, as the node of nanolithography technology in integrated circuits decreases to below 14nm, and the demand for three-dimensional nanostructure devices increases, how to successfully obtain three-dimensional micro-nano structures with good exposure quality within such a small feature size range has become an important problem that needs to be solved in surface plasmonic grayscale lithography systems.

[0005] In surface plasmon lithography (SPL), by modulating the pulse response of the exposure source and knowing the spatial distribution of the three-dimensional structural features of the target pattern, a deconvolution process is used to obtain an exposure map consisting of the required exposure time for the target pattern. This map is then used as the input image for exposure. Experimental results verify that this method can obtain three-dimensional micro / nano structures with feature sizes ranging from tens of nanometers to several micrometers. However, this method requires three-dimensional modeling and analysis of the field intensity distribution at the BNA opening during the deconvolution process to obtain the required exposure time for the target pattern at a specific exposure depth and width. Due to the complexity of the near-field field intensity distribution of the BNA and the inaccuracy of the modeling, this method struggles to achieve resolution for feature sizes of 20 nm and below, and it also involves significant computational costs. Therefore, it lacks practical applicability in fabricating three-dimensional micro / nano structures with multiple feature sizes and complex exposure pattern contours. Summary of the Invention

[0006] The purpose of this application is to provide a method and apparatus for manufacturing three-dimensional micro-nano structures based on a surface plasmon grayscale lithography system, in order to solve the problems of complexity and inaccuracy in the modeling of existing methods based on the near-field field intensity distribution of bow-shaped nanopores. These methods are difficult to obtain resolution with feature sizes of 20 nanometers or less, and involve a large amount of computation. They also lack practical applicability when manufacturing three-dimensional micro-nano structures with multiple feature sizes and complex exposure pattern contours.

[0007] In a first aspect, this application provides a method for manufacturing three-dimensional micro / nano structures based on a surface plasmonic grayscale lithography system, the method comprising:

[0008] To obtain the spatial distribution characteristics of the electric field at the opening of the bow-shaped nanopore in a surface plasmon grayscale lithography system;

[0009] Based on the aforementioned spatial distribution characteristics of the field strength, the correspondence between the spatial distribution characteristics of the field strength and the size of the gap in the bow-shaped nanopores is determined.

[0010] Based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, the exposure dose of the surface plasma grayscale lithography system is grayscale controlled to determine the grayscale exposure input pattern corresponding to the target three-dimensional micro / nano structure.

[0011] The grayscale exposure input pattern is input into the lithography imaging model and photoresist imaging model of the surface plasma grayscale lithography system for exposure processing, and the corresponding pattern quality parameters are determined.

[0012] Using the above technical solution, the three-dimensional micro / nano structure manufacturing method based on a surface plasmonic grayscale lithography system provided in this application can obtain the spatial distribution characteristics of the field intensity of the surface plasmonic grayscale lithography system at the opening of the bow-shaped nanopores. Based on the spatial distribution characteristics of the field intensity, the correspondence between the spatial distribution characteristics of the field intensity and the gap size of the bow-shaped nanopores is determined. Based on the correspondence between the spatial distribution characteristics of the field intensity and the gap size, the exposure dose of the surface plasmonic grayscale lithography system is grayscale controlled to determine the grayscale exposure input pattern corresponding to the target three-dimensional micro / nano structure. The grayscale exposure input pattern is then input to the surface plasmonic grayscale lithography system. Exposure processing was performed on the lithography imaging model and photoresist imaging model of the plasma grayscale lithography system to determine the pattern quality parameters corresponding to the exposed pattern. Quantitative analysis of the unique near-field attenuation characteristics of surface plasmon lithography revealed a dimensional scaling behavior between the near-field attenuation characteristics of the plasma excited at the BNA opening and its gap size. Furthermore, a comparison of the photoresist contrast between the surface plasmon lithography system and the traditional optical lithography system showed that, due to the influence of near-field attenuation characteristics, the photoresist contrast of surface plasmon lithography is wider, meaning that the controllability of the required exposure dose per unit volume is higher. In addition, the introduction of grayscale exposure input patterns is the physical essence of the surface plasmon lithography system's ability to fabricate three-dimensional micro / nano structures. By converting the target image input during exposure in a surface plasmon lithography system to grayscale, and by introducing the discontinuous distribution of sub-pixels and impulse responses, while simultaneously controlling the spatial distribution of the feature size of the target three-dimensional micro / nano structure and the required exposure dose, it is possible not only to obtain high-resolution multi-size three-dimensional micro / nano structures, but also to reduce the feature error between the exposed image and the target image through grayscale exposure input image calibration, thus obtaining high-fidelity three-dimensional exposure results. Therefore, the surface plasmon grayscale lithography technology proposed in this application can greatly improve the exposure quality of three-dimensional micro / nano structures and has significant practical applicability. Applying grayscale image exposure to maskless surface plasmon lithography technology is a major approach to obtaining high-resolution and high-fidelity three-dimensional micro / nano structures, which is of great significance for further research on low-cost, large-area, and high-quality three-dimensional micro / nano structure fabrication.

[0013] In one possible implementation, the acquisition of the spatial distribution characteristics of the field intensity at the bow-shaped nanopore opening of the surface plasmon grayscale lithography system includes:

[0014] The point spread function of the surface plasmonic grayscale lithography system at the bow-shaped nanopore opening was obtained using simulation software.

[0015] The transverse and longitudinal field strength attenuation characteristics are determined based on the point spread function.

[0016] In one possible implementation, determining the correspondence between the spatial distribution characteristics of the field strength and the size of the bow-shaped nanopores based on the spatial distribution characteristics of the field strength includes:

[0017] The transverse and longitudinal field strength attenuation characteristics corresponding to the opening of the bow-shaped nanopores were modeled and analyzed, and it was determined that there is a size scaling behavior characteristic between the field strength distribution in both the transverse and longitudinal directions and the gap of the bow-shaped nanopores.

[0018] In one possible implementation, the size scaling behavior is such that, regardless of the size of the gap between the bow nanopores, there is a strong field strength attenuation characteristic at the opening of the bow nanopores, and as the size of the exposed pattern feature of the bow nanopores decreases, the field strength attenuation characteristic becomes stronger but the attenuation trend remains unchanged.

[0019] In one possible implementation, after determining the correspondence between the spatial distribution characteristics of the field strength and the size of the bow-shaped nanopore gap based on the spatial distribution characteristics of the field strength, and before performing grayscale adjustment of the exposure dose of the surface plasmonic grayscale lithography system based on the correspondence between the spatial distribution characteristics of the field strength and the gap size to determine the grayscale exposure input pattern corresponding to the target three-dimensional micro / nano structure, the method further includes:

[0020] The contrast curves of the first photoresist corresponding to the surface plasma grayscale lithography system and the second photoresist corresponding to the conventional optical lithography system were obtained respectively.

[0021] By comparing the first bandwidth of the first photoresist contrast curve and the second bandwidth of the second photoresist contrast curve, it is determined that the first bandwidth is greater than the second bandwidth.

[0022] When the first bandwidth is greater than the second bandwidth, it is determined that the surface plasmonic grayscale lithography system has a higher controllability of the required exposure dose per unit volume than the conventional optical lithography system.

[0023] In one possible implementation, the grayscale control of the exposure dose of the surface plasmonic grayscale lithography system based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, to determine the grayscale exposure input pattern corresponding to the target three-dimensional micro / nano structure, includes:

[0024] Based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, the exposure dose of the surface plasma grayscale lithography system is grayscale controlled by spatially adjusting the pulse width of the light source laser.

[0025] Obtain the calibration curves of grayscale exposure dose, exposure pattern depth, and exposure pattern width corresponding to the grayscale adjustment;

[0026] The grayscale exposure input graphic corresponding to the target three-dimensional micro / nano structure is determined based on the calibration curve.

[0027] In one possible implementation, the grayscale control of the exposure dose of the surface plasmonic grayscale lithography system, based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, and achieved through spatial modulation of the pulse width of the light source laser, includes:

[0028] Based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, by adding sub-pixels and applying continuous or discontinuous pulse response control to the sub-pixels, the grayscale exposure dose is divided into multiple levels to determine the correspondence between the pulse response and the grayscale exposure dose.

[0029] In one possible implementation, obtaining the calibration curve of grayscale exposure dose versus exposure pattern depth and exposure pattern width after grayscale adjustment includes:

[0030] Based on the correspondence between the impulse response and the grayscale exposure dose, a calibration curve is determined for the grayscale exposure dose and the exposure pattern depth and width.

[0031] In one possible implementation, obtaining the first photoresist contrast curve corresponding to the surface plasmonic grayscale lithography system and the second photoresist contrast curve corresponding to the conventional optical lithography system respectively includes:

[0032] Obtain the first exposure result of the dot mapping pattern corresponding to the surface plasma grayscale lithography system within the photoresist;

[0033] Obtain the second exposure result of the dot mapping pattern corresponding to the photoresist in the conventional optical lithography system;

[0034] Based on the first graphic feature size and the first exposure dose corresponding to the first exposure result, the first photoresist contrast curves corresponding to the surface plasma grayscale lithography system in the longitudinal and transverse directions are determined.

[0035] Based on the second pattern feature size and the second exposure dose corresponding to the second exposure result, the second photoresist contrast curve corresponding to the conventional optical lithography system in the vertical and horizontal directions is determined.

[0036] Secondly, this application also provides a three-dimensional micro / nano structure manufacturing apparatus based on a surface plasmonic grayscale lithography system, the apparatus comprising:

[0037] The acquisition module is used to acquire the spatial distribution characteristics of the field strength of the surface plasmon grayscale lithography system at the opening of the bow-shaped nanopore.

[0038] The first determining module is used to determine the correspondence between the spatial distribution characteristics of the field strength and the size of the gap between the bow-shaped nanopores based on the spatial distribution characteristics of the field strength.

[0039] The second determining module is used to grayscale control the exposure dose of the surface plasma grayscale lithography system based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, and to determine the grayscale exposure input pattern corresponding to the target three-dimensional micro-nano structure.

[0040] The third determining module is used to input the grayscale exposure input pattern into the lithography imaging model and photoresist imaging model of the surface plasma grayscale lithography system for exposure processing, and to determine the pattern quality parameters corresponding to the exposed pattern.

[0041] In one possible implementation, the acquisition module includes:

[0042] The first acquisition submodule is used to acquire the point spread function of the surface plasmonic grayscale lithography system at the bow-shaped nano-aperture opening through simulation software;

[0043] The first determining submodule is used to determine the transverse field strength attenuation characteristics and the longitudinal field strength attenuation characteristics based on the point spread function.

[0044] In one possible implementation, the first determining module includes:

[0045] The second determining submodule is used to model and analyze the transverse field strength attenuation characteristics and longitudinal field strength attenuation characteristics corresponding to the opening of the bow nanopore, and to determine that there are size scaling behavior characteristics between the field strength distribution in the transverse and longitudinal directions and the gap of the bow nanopore.

[0046] In one possible implementation, the size scaling behavior is such that, regardless of the size of the gap between the bow nanopores, there is a strong field strength attenuation characteristic at the opening of the bow nanopores, and as the size of the exposed pattern feature of the bow nanopores decreases, the field strength attenuation characteristic becomes stronger but the attenuation trend remains unchanged.

[0047] In one possible implementation, the device further includes:

[0048] The second acquisition submodule is used to acquire the first photoresist contrast curve corresponding to the surface plasma grayscale lithography system and the second photoresist contrast curve corresponding to the conventional optical lithography system, respectively.

[0049] The third determining submodule is used to compare the first bandwidth of the first photoresist contrast curve and the second bandwidth of the second photoresist contrast curve, and determine that the first bandwidth is greater than the second bandwidth.

[0050] The fourth determining submodule is used to determine, when the first bandwidth is greater than the second bandwidth, that the controllability of the surface plasmonic grayscale lithography system for the required exposure dose per unit volume is higher than that of the conventional optical lithography system for the required exposure dose.

[0051] In one possible implementation, the second determining module includes:

[0052] The control submodule is used to control the exposure dose of the surface plasma grayscale lithography system by spatially controlling the pulse width of the light source laser, based on the correspondence between the spatial distribution characteristics of the field strength and the gap size.

[0053] The third acquisition submodule is used to acquire the calibration curve of grayscale exposure dose, exposure pattern depth and exposure pattern width corresponding to the grayscale adjustment.

[0054] The fifth determining submodule is used to determine the grayscale exposure input graphic corresponding to the target three-dimensional micro / nano structure based on the calibration curve.

[0055] In one possible implementation, the control submodule includes:

[0056] The first determining unit is used to determine the correspondence between the pulse response and the grayscale exposure dose by adding sub-pixels and applying continuous or discontinuous pulse response control to the sub-pixels based on the correspondence between the spatial distribution characteristics of the field strength and the gap size.

[0057] In one possible implementation, the third acquisition submodule includes:

[0058] The second determining unit is used to determine a calibration curve of the grayscale exposure dose, the exposure pattern depth, and the exposure pattern width based on the correspondence between the pulse response and the grayscale exposure dose.

[0059] In one possible implementation, the second acquisition submodule includes:

[0060] The first acquisition unit is used to acquire the first exposure result of the dot mapping pattern corresponding to the surface plasma grayscale lithography system in the photoresist;

[0061] The second acquisition unit is used to acquire the second exposure result of the dot mapping pattern corresponding to the photoresist in the conventional optical lithography system;

[0062] The third determining unit is used to determine the first photoresist contrast curve corresponding to the surface plasma grayscale lithography system in the longitudinal and transverse directions based on the first graphic feature size and the first exposure dose corresponding to the first exposure result.

[0063] The fourth determining unit is used to determine the second photoresist contrast curve corresponding to the conventional optical lithography system in the longitudinal and transverse directions based on the second pattern feature size and the second exposure dose corresponding to the second exposure result.

[0064] The beneficial effects of the three-dimensional micro / nano structure manufacturing apparatus based on a surface plasmonic grayscale lithography system provided in the second aspect are the same as those of the three-dimensional micro / nano structure manufacturing method based on a surface plasmonic grayscale lithography system described in the first aspect or any possible implementation of the first aspect, and will not be repeated here. Attached Figure Description

[0065] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0066] Figure 1 A schematic flowchart of a three-dimensional micro / nano structure fabrication method based on a surface plasmonic grayscale lithography system provided in an embodiment of this application is shown.

[0067] Figure 2 A schematic flowchart of another three-dimensional micro / nano structure fabrication method based on a surface plasmonic grayscale lithography system provided in this application embodiment is shown.

[0068] Figure 3 This paper shows a schematic diagram of the structure of a surface plasma grayscale lithography system provided in an embodiment of this application;

[0069] Figure 4 This illustration shows a schematic diagram of the gap size scaling behavior on a field strength distribution according to an embodiment of this application;

[0070] Figure 5 (a) shows a schematic diagram of the light intensity distribution required for an exposure pattern according to an embodiment of this application;

[0071] Figure 5 (b) illustrates a grayscale diagram of an exposure dose value provided in an embodiment of this application;

[0072] Figure 5 (c) shows a schematic diagram illustrating the quantitative relationship between the feature size of the photoresist in-stencil exposure pattern and the grayscale exposure dose according to an embodiment of this application;

[0073] Figure 6 This illustration shows a schematic diagram of the correspondence between a grayscale exposure input pattern and the discontinuous pulse response of a lithography system, as provided in an embodiment of this application.

[0074] Figure 7 This illustration shows a schematic diagram of a grayscale exposure input pattern corresponding to a three-dimensional nanolens array structure provided in an embodiment of this application;

[0075] Figure 8 This diagram illustrates the final exposure result of a three-dimensional nanolens array structure in photoresist according to an embodiment of this application.

[0076] Figure 9 This paper presents a schematic diagram of a three-dimensional micro / nano structure manufacturing apparatus based on a surface plasmonic grayscale lithography system, as provided in an embodiment of this application. Attached image description:

[0078] 01-Silicon substrate; 02-Photoresist; 03-Aluminum film layer; 04-Silicon nitride film layer. Detailed Implementation

[0079] To facilitate a clear description of the technical solutions in the embodiments of this application, the terms "first" and "second" are used in the embodiments of this application to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are only used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and the terms "first" and "second" are not necessarily different.

[0080] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0081] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0082] Various micro-nano devices fabricated based on three-dimensional micro-nano structures have higher integration and better electrical, optical, magnetic and mechanical properties, enabling them to achieve application functions that planar two-dimensional micro-nano devices cannot obtain. Therefore, they are in high demand in fields including integrated circuits, nano-optics, micro-nano electromechanical systems and biomimetic technology.

[0083] Currently, the main methods for fabricating three-dimensional micro and nanostructures include electron beam lithography (EBL), focused ion beam (FIB) milling, interference lithography, laser three-dimensional direct writing, and grayscale lithography.

[0084] Electron beam lithography, with its high resolution and long depth of focus, can fabricate micro- and nanostructures with feature sizes within 10 nanometers (nm). However, its lithography efficiency is too low, making it unsuitable for mass industrial production. While focused ion beam lithography boasts high resolution and exposure efficiency, the edges of the exposed patterns become increasingly rough with minimal increases in exposure efficiency, severely limiting the functionality of three-dimensional micro- and nano-devices. Interference lithography offers advantages in fabricating large-area, high-resolution micro- and nano-structures, but the difficulty in controlling the relative intensity and phase of interference fringes, coupled with significant high-frequency information loss, severely restricts the exposure quality of three-dimensional structures. Laser-based three-dimensional direct writing technology is unsuitable for large-scale manufacturing of three-dimensional micro- and nano-structures due to its extremely complex and expensive equipment and low scanning efficiency.

[0085] Compared to other 3D micro / nano fabrication technologies, grayscale lithography offers numerous advantages. These include single-step lithography, where the energy density distribution of an incident light beam can be modulated into arbitrary shapes using a grayscale mask. After exposure of the photoresist, a 3D micro / nano structure can be formed in a single step. It also boasts strong compatibility, requiring only a certain encoding of the mask, making the process simple and easily compatible with other IC processes. However, because the physical essence of grayscale lithography is to use a grayscale mask as a spatial filter, controlling the pixels and their spacing on the grayscale mask to modulate the amplitude of the light beam, thereby achieving arbitrary distribution of light energy density on the projected imaging surface, the resolution achievable by grayscale lithography is limited by light diffraction.

[0086] Surface plasmon lithography (SPL) is a nano-optical lithography technique capable of breaking the diffraction limit. It primarily utilizes a bow-shaped nanopore structure to generate surface plasmon polariton modes and quasi-spherical wave diffraction fields at the BNA openings under ultraviolet light exposure, transferring the exposed pattern into the photoresist for super-resolution imaging. As a high-resolution, low-cost nanofabrication technique, SPL has been proven to achieve resolutions below 10 nanometers (nm). Due to its excellent controllability and scalability of nanoscale feature sizes, it has successfully produced various surface micro / nano structures. Furthermore, based on the near-field imaging characteristics of SPL, a rule-based optical proximity effect correction method is proposed, significantly improving the quality of the exposed pattern. Moreover, by proposing a hybrid surface plasmon waveguide exposure structure, the problem of shallow exposure depth in SPL is effectively solved, enabling the aspect ratio of the exposed pattern to exceed 1.

[0087] However, as the node of nanolithography technology in integrated circuits decreases to below 14nm, and the demand for three-dimensional nanostructure devices increases, how to successfully obtain three-dimensional micro-nano structures with good exposure quality within such a small feature size (Critical Dimension, CD) has become an important problem that needs to be solved in surface plasmon lithography technology.

[0088] In surface plasmon lithography, by modulating the pulse response of the exposure light source, and given the known spatial distribution information of the three-dimensional structure of the target pattern, an exposure map consisting of the required exposure time of the target pattern can be obtained using a deconvolution process. This map is then used as the input image for exposure. Experimental results verify that this method can obtain three-dimensional micro-nano structures with feature sizes ranging from tens of nanometers to several micrometers.

[0089] However, this method requires three-dimensional modeling and analysis of the field intensity distribution at the BNA opening during the deconvolution analysis process to obtain the exposure time required for the target pattern at a specific exposure depth and width. Due to the complexity of the BNA near-field field intensity distribution and the inaccuracy of the modeling, this method struggles to achieve resolutions with feature sizes of 20 nm or less, and it also involves significant computational demands. Consequently, it lacks practical applicability in fabricating three-dimensional micro / nano structures with multiple feature sizes and complex exposure pattern contours.

[0090] Therefore, this application proposes a simple, fast, efficient, low-cost, and high-precision method for manufacturing three-dimensional micro / nano structures, which we call surface plasmon grayscale lithography. This surface plasmon grayscale lithography combines the ability of surface plasmon lithography to achieve super-diffraction optical resolution with the ability of grayscale lithography to precisely control the feature size of the exposed pattern. Through quantitative analysis of the decaying feature of evanescent waves at the BNA aperture, it was found that due to its unique rapid near-field decay characteristics, surface plasmon lithography results in a photoresist contrast curve with a wider required exposure dose bandwidth compared to the photoresist contrast curve in traditional optical lithography. This characteristic allows for more precise control of the feature size of the exposed pattern during three-dimensional structure exposure. However, the rapid decay of the evanescent waves leads to the rapid loss of high-frequency information, resulting in distortion of the final exposed pattern within the photoresist. To compensate for this exposure pattern distortion, a grayscale-patterned exposure map based on the attenuation characteristics of evanescent wave field strength can be used as a spatial filter. By precisely controlling its spatial distribution, the required exposure dose for three-dimensional micro / nano structures can be precisely controlled, thereby obtaining high-resolution and high-exposure-quality three-dimensional micro / nano structures. This provides technical support for further improving the practical application of surface plasmon grayscale lithography technology. Specifically, this includes:

[0091] Figure 1 This document illustrates a flowchart of a three-dimensional micro / nano structure fabrication method based on a surface plasmonic grayscale lithography system, as provided in an embodiment of this application. Figure 1 As shown, the three-dimensional micro / nano structure fabrication method based on a surface plasmonic grayscale lithography system includes:

[0092] Step 101: Obtain the spatial distribution characteristics of the field strength at the bow-shaped nanopore opening of the surface plasmon grayscale lithography system.

[0093] In this application, the point spread function of the surface plasmon grayscale lithography system at the bow-shaped nanopore opening can be obtained by simulation software; the transverse field strength attenuation characteristics and the longitudinal field strength attenuation characteristics are determined based on the point spread function.

[0094] After obtaining the spatial distribution characteristics of the field strength at the bow-shaped nanopore opening of the surface plasmon grayscale lithography system, step 102 is performed.

[0095] Step 102: Determine the correspondence between the spatial distribution characteristics of the field strength and the size of the gap between the bow-shaped nanopores based on the spatial distribution characteristics of the field strength.

[0096] The transverse and longitudinal field strength attenuation characteristics corresponding to the opening of the bow-shaped nanopores can be modeled and analyzed to determine that there are size scaling behaviors between the field strength distribution in both the transverse and longitudinal directions and the gap of the bow-shaped nanopores.

[0097] It should be noted that the gap size scaling behavior is characterized by a strong field strength attenuation at the opening of the bow nanopores regardless of the size of the gap. Furthermore, as the size of the exposed pattern feature of the bow nanopores decreases, the field strength attenuation becomes stronger, but the attenuation trend remains unchanged.

[0098] After determining the correspondence between the spatial distribution characteristics of the field strength and the size of the gap between the bow-shaped nanopores based on the spatial distribution characteristics of the field strength, step 103 is executed.

[0099] Step 103: Based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, the exposure dose of the surface plasma grayscale lithography system is grayscale controlled to determine the grayscale exposure input pattern corresponding to the target three-dimensional micro / nano structure.

[0100] In this application, the exposure dose of the surface plasmonic grayscale lithography system can be grayscale controlled by spatially adjusting the pulse width of the laser source, based on the correspondence between the spatial distribution characteristics of the field strength and the gap size. A calibration curve is obtained showing the grayscale exposure dose, exposure pattern depth, and exposure pattern width after the grayscale control. Based on the calibration curve, the grayscale exposure input pattern corresponding to the target three-dimensional micro / nano structure is determined.

[0101] After grayscale control of the exposure dose of the surface plasma grayscale lithography system based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, and determining the grayscale exposure input pattern corresponding to the target three-dimensional micro / nano structure, step 104 is executed.

[0102] Step 104: Input the grayscale exposure input pattern into the lithography imaging model and photoresist imaging model of the surface plasma grayscale lithography system for exposure processing, and determine the pattern quality parameters corresponding to the exposed pattern.

[0103] In summary, the three-dimensional micro / nano structure manufacturing method based on a surface plasmonic grayscale lithography system provided in this application can obtain the spatial distribution characteristics of the field intensity at the opening of the bow-shaped nanopore in the surface plasmonic grayscale lithography system. Based on the spatial distribution characteristics of the field intensity, the correspondence between the spatial distribution characteristics of the field intensity and the gap size of the bow-shaped nanopore is determined. Based on the correspondence between the spatial distribution characteristics of the field intensity and the gap size, the exposure dose of the surface plasmonic grayscale lithography system is grayscale controlled to determine the grayscale exposure input pattern corresponding to the target three-dimensional micro / nano structure. The grayscale exposure input pattern is then input into the surface plasmonic grayscale lithography system. Exposure processing was performed using the photolithography imaging model and photoresist imaging model of the plasmon lithography system to determine the pattern quality parameters corresponding to the exposed pattern. Quantitative analysis of the unique near-field attenuation characteristics of plasmon lithography revealed a dimensional scaling behavior between the near-field attenuation characteristics of the plasma excited at the BNA opening and its gap size. Furthermore, a comparison of the photoresist contrast between the plasmon lithography system and the traditional optical lithography system showed that, due to the influence of near-field attenuation characteristics, the photoresist contrast of plasmon lithography is wider, meaning that the controllability of the required exposure dose per unit volume is higher. In addition, the introduction of grayscale exposure input patterns is the physical essence of the plasmon lithography system's ability to fabricate three-dimensional micro / nano structures. By converting the target image input during exposure in a surface plasmon lithography system to grayscale, and by introducing the discontinuous distribution of sub-pixels and impulse responses, while simultaneously controlling the spatial distribution of the feature size of the target three-dimensional micro / nano structure and the required exposure dose, it is possible not only to obtain high-resolution multi-size three-dimensional micro / nano structures, but also to reduce the feature error between the exposed image and the target image through grayscale exposure input image calibration, thus obtaining high-fidelity three-dimensional exposure results. Therefore, the surface plasmon grayscale lithography technology proposed in this application can greatly improve the exposure quality of three-dimensional micro / nano structures and has significant practical applicability. Applying grayscale image exposure to maskless surface plasmon lithography technology is a major approach to obtaining high-resolution and high-fidelity three-dimensional micro / nano structures, which is of great significance for further research on low-cost, large-area, and high-quality three-dimensional micro / nano structure fabrication.

[0104] Figure 2 This paper illustrates a flowchart of another three-dimensional micro / nano structure fabrication method based on a surface plasmonic grayscale lithography system provided in an embodiment of this application. Figure 2As shown, the method for fabricating three-dimensional micro / nano structures based on a surface plasmonic grayscale lithography system includes:

[0105] Step 201: Obtain the spatial distribution characteristics of the field strength at the bow-shaped nanopore opening of the surface plasmon grayscale lithography system.

[0106] In this application, the point spread function of the surface plasmon grayscale lithography system at the bow-shaped nanopore opening can be obtained by simulation software; the transverse field strength attenuation characteristics and the longitudinal field strength attenuation characteristics are determined based on the point spread function.

[0107] Optionally, the point spread function of the surface plasmon grayscale lithography system can be obtained through the lumerical FDTD simulation software, which is to obtain the three-dimensional field intensity distribution within the photoresist.

[0108] Figure 3 This paper illustrates a schematic diagram of a surface plasma grayscale lithography system provided in an embodiment of this application. Figure 3 As shown, it includes a silicon substrate 01 and a photoresist 02 disposed on the silicon substrate 01, and also includes a bow-shaped nanopore structure composed of an aluminum film layer 03 and a silicon nitride film layer 04. The incident light wavelength is 365 nanometers, and cross-polarization (x-pol) is performed at the aperture opening corresponding to the bow-shaped nanopore (BNA) structure. The exposure dose modulation corresponds to the width (W) and depth (d). The intensity represents low intensity and high intensity.

[0109] In this application, the point spread function of the surface plasmon grayscale lithography system can not only determine the feature size of the exposed pattern in the photoresist, but also represent the specific distribution of the exposure field intensity in the photoresist. Therefore, the point spread function can be used to quantitatively analyze the spatial distribution characteristics of its field intensity.

[0110] Due to the unique geometric characteristics of the BNA structure, the near-field field strength distribution of the plasma excited at the opening of the BNA structure is very complex. In particular, the degree of influence from the propagating wave and non-propagating wave characteristics is different, resulting in different field strength spaces in both the transverse and longitudinal directions, and each with different field strength attenuation characteristics.

[0111] Among them, the transverse propagation field strength I(r) corresponding to the transverse field strength attenuation characteristic is shown in Equation (1), and the longitudinal propagation field strength I(z) corresponding to the longitudinal field strength attenuation characteristic is shown in Equation (2):

[0112]

[0113] Where r is the radius from the center of BNA, g is the size of the gap in BNA, z is the distance from the BNA outlet, Ii is the intensity at r = z = 0, C1 is the Gaussian fitting parameter, and C2 is the field strength attenuation constant in the z direction.

[0114] The point-spread function (PSF) of surface plasmon lithography (SPPs) is mainly determined by the evanescent wave modes of SPPs and QSWs. It exhibits strong field strength attenuation not only in the direction perpendicular to it but also in the transverse direction, demonstrating complex and strong attenuation characteristics. Quantitative analysis of the attenuation characteristics of plasmon BNA structures with different gap sizes (g) revealed a certain gap size scaling behavior in the evanescent field strength attenuation at the opening of the plasmon BNA.

[0115] After obtaining the spatial distribution characteristics of the field strength at the bow-shaped nanopore opening of the surface plasmon grayscale lithography system, step 202 is performed.

[0116] Step 202: Determine the correspondence between the spatial distribution characteristics of the field strength and the size of the gap between the bow-shaped nanopores based on the spatial distribution characteristics of the field strength.

[0117] Figure 4 This illustration shows a schematic diagram of the gap size scaling behavior in a field strength distribution according to an embodiment of this application, as shown below. Figure 4 As shown in (a), the gap size scaling behavior in the transverse field strength distribution is as follows: Figure 4 As shown in (b), the vertical gap sizes scaling behavior is illustrated, where the vertical axis represents the normalized intensity, the unit (au) is arbitrary, and the calculation represents the calculation results, such as... Figure 4 As shown, the transverse and longitudinal field strength attenuation characteristics corresponding to the opening of the bow nanopores can be modeled and analyzed to determine that there are size scaling behaviors between the field strength distribution in both the transverse and longitudinal directions and the gap of the bow nanopores.

[0118] It should be noted that the gap size scaling behavior is characterized by a strong field strength attenuation at the opening of the bow nanopores regardless of the size of the gap. Furthermore, as the size of the exposed pattern feature of the bow nanopores decreases, the field strength attenuation becomes stronger, but the attenuation trend remains unchanged.

[0119] In this application, after step 203, the method further includes: acquiring a first photoresist contrast curve corresponding to the surface plasmon grayscale lithography system and a second photoresist contrast curve corresponding to the conventional optical lithography system. A first bandwidth of the first photoresist contrast curve and a second bandwidth of the second photoresist contrast curve are compared, and it is determined that the first bandwidth is greater than the second bandwidth. When the first bandwidth is greater than the second bandwidth, it is determined that the controllability of the surface plasmon grayscale lithography system for the required exposure dose per unit volume is higher than that of the conventional optical lithography system for the required exposure dose.

[0120] Specifically, the system can obtain a first exposure result of the dot mapping pattern corresponding to the surface plasmon grayscale lithography system within the photoresist; obtain a second exposure result of the dot mapping pattern corresponding to the conventional optical lithography system within the photoresist; determine the first photoresist contrast curve corresponding to the surface plasmon grayscale lithography system in the vertical and horizontal directions based on the first pattern feature size and the first exposure dose corresponding to the first exposure result; and determine the second photoresist contrast curve corresponding to the conventional optical lithography system in the vertical and horizontal directions based on the second pattern feature size and the second exposure dose corresponding to the second exposure result.

[0121] In this application, by comparing the photoresist contrast curve with that of traditional optical lithography, it was found that the unique near-field intensity attenuation characteristic of plasmonic BNA structures results in a wider photoresist contrast curve in surface plasmonic grayscale lithography. This means that a wider bandwidth of exposure dose per unit volume is required during pattern exposure. This characteristic allows for more precise control of the feature size of the exposed pattern during three-dimensional structure exposure in surface plasmonic grayscale lithography.

[0122] After determining the correspondence between the spatial distribution characteristics of the field strength and the size of the gap between the bow-shaped nanopores based on the spatial distribution characteristics of the field strength, step 203 is executed.

[0123] Step 203: Based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, the exposure dose of the surface plasma grayscale lithography system is grayscale controlled by spatially adjusting the pulse width of the light source laser.

[0124] In this application, based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, the grayscale exposure dose can be divided into multiple levels by adding sub-pixels and applying continuous or discontinuous pulse response control to the sub-pixels, thereby determining the correspondence between the pulse response and the grayscale exposure dose.

[0125] Specifically, the exposure dose value of the surface plasmon grayscale lithography system can be controlled in a grayscale manner by discontinuously modulating the pulse response of the system. As a maskless lithography technique, surface plasmon grayscale lithography eliminates the need for a physical mask when exposing a target pattern, but it still requires an input pattern capable of reproducing the dimensional features of the target pattern. Figure 5 (a) shows a schematic diagram of the light intensity distribution required for an exposure pattern according to an embodiment of this application. The horizontal axis represents the lateral position, and the vertical axis represents the light intensity. Figure 5 (b) illustrates a grayscale diagram of an exposure dose value provided in an embodiment of this application, which is a grayscale exposure map (Grayscale). Figure 5 (c) shows a schematic diagram of the quantitative relationship between the feature size of the photoresist in-situ exposure pattern and the grayscale exposure dose provided in the embodiment of this application, which is also a pattern profile diagram. The surface plasma grayscale lithography system can grayscale the input pattern of the three-dimensional micro-nano structure, so that the feature size of the target three-dimensional micro-nano structure and the spatial distribution of the required exposure dose can be controlled at the same time, thereby realizing the pattern exposure of the three-dimensional micro-nano structure.

[0126] Figure 6 This illustration shows a schematic diagram of the correspondence between a grayscale exposure input pattern and the discontinuous pulse response of a lithography system, provided in an embodiment of this application. In this diagram, Grayscale exposure map represents a grayscale exposure map, Spatial modulation represents spatial modulation, Discrete sub-pixel represents a discrete sub-pixel, Dwell Time represents the waiting time, and Sub-pixel represents a sub-pixel. Figure 6 As shown, the grayscale control of the exposure dose can be achieved by spatially adjusting the pulse width of the laser source in the surface plasmon grayscale lithography system. Furthermore, by adding sub-pixels and adjusting the sub-pixels continuously or discontinuously, the grayscale exposure dose can be divided into multiple levels. Although theoretically the grayscale value range is 0 to 255, the leveling of the exposure dose can far exceed this value.

[0127] In this application, by discontinuously modulating the pulse response of the surface plasmonic grayscale lithography system, a grayscale exposure input pattern that can reproduce the target three-dimensional micro-nano structure is obtained, thereby realizing the control of the depth and exposure width of the exposure pattern, that is, realizing the spatial control of the feature size of the target three-dimensional micro-nano structure.

[0128] After the exposure dose of the surface plasmonic grayscale lithography system is grayscale controlled by spatially adjusting the pulse width of the light source laser based on the correspondence between the spatial distribution characteristics of the field strength and the gap size, step 204 is executed.

[0129] Step 204: Obtain the calibration curve of grayscale exposure dose, exposure pattern depth and exposure pattern width corresponding to the grayscale adjustment.

[0130] In this application, based on the correspondence between the impulse response and the grayscale exposure dose, a calibration curve is determined for the grayscale exposure dose and the exposure pattern depth and width.

[0131] After obtaining the calibration curves of grayscale exposure dose, exposure pattern depth, and exposure pattern width corresponding to the grayscale adjustment, step 205 is executed.

[0132] Step 205: Determine the grayscale exposure input graphic corresponding to the target three-dimensional micro / nano structure based on the calibration curve.

[0133] In this application, a grayscale exposure input image corresponding to the target three-dimensional micro / nano structure can be constructed based on the calibration curve. Figure 7 This illustration shows a schematic diagram of a grayscale exposure input pattern corresponding to a three-dimensional nanolens array structure provided in an embodiment of this application, as shown below. Figure 7 As shown, the grayscale exposure input pattern corresponding to the three-dimensional nanolens array structure, 0 to 255, corresponds to different exposure depths of 40 to 100 nanometers.

[0134] In this application, a grayscale exposure input pattern capable of reproducing the target three-dimensional micro / nano structure is obtained by discontinuously modulating the pulse response of a surface plasmon grayscale lithography system. This allows for the control of the depth and width of the exposure pattern, i.e., spatial control of the feature dimensions of the target three-dimensional micro / nano structure. Furthermore, considering the influence of near-field attenuation characteristics on the final exposure pattern contour, the spatial distribution of the grayscale exposure input pattern is further refined to improve the fidelity of the exposure pattern. This pattern exposure method achieves both high optical resolution and ensures the realization of multiple feature dimensions, reducing the error between the exposed pattern and the target pattern, and improving the fidelity of the exposure pattern, thus possessing strong practical applicability.

[0135] After determining the grayscale exposure input graphic corresponding to the target three-dimensional micro / nano structure based on the calibration curve, step 206 is executed.

[0136] Step 206: Input the grayscale exposure input pattern into the lithography imaging model and photoresist imaging model of the surface plasma grayscale lithography system for exposure processing, and determine the pattern quality parameters corresponding to the exposed pattern.

[0137] In this application, a lithographic imaging model and a photoresist imaging model of a surface plasmonic grayscale lithography system can be established, and a grayscale exposure input image can be used as the input image for exposure, and the quality of the exposed image can be analyzed. Figure 8 This illustration shows a schematic diagram of the final exposure result of a three-dimensional nanolens array structure in photoresist according to an embodiment of this application. Figure 8 As shown, its minimum feature size is 18 nanometers.

[0138] The three-dimensional micro / nano structure manufacturing method proposed in this application has a simple structure for its corresponding surface plasmonic grayscale lithography system. The manufacturing method is fast, efficient, low-cost, and highly accurate. The system also has the advantages of achieving super-diffraction optical resolution and precise control of the size of the exposed pattern features.

[0139] Furthermore, through quantitative analysis of the unique near-field attenuation characteristics of surface plasmon lithography, it was found that there is a certain size scaling behavior between the near-field attenuation characteristics of the plasma excited at the BNA opening and the size of its gap. Moreover, by comparing the photoresist contrast of surface plasmon lithography system and traditional optical lithography system, it was found that due to the influence of near-field attenuation characteristics, the photoresist contrast of surface plasmon lithography is wider, which means that the controllability of the required exposure dose per unit volume is higher.

[0140] Furthermore, the introduction of grayscale exposure input patterns is the physical essence of why surface plasmon lithography systems can perform three-dimensional micro / nanostructure fabrication. By grayscaleing the target pattern input pattern during exposure in the surface plasmon lithography system, and by introducing the discontinuous distribution of sub-pixels and impulse responses, while simultaneously controlling the spatial distribution of the feature size of the target three-dimensional micro / nanostructure and the required exposure dose, not only can high-resolution multi-size three-dimensional micro / nanostructures be obtained, but also the feature error between the exposed pattern and the target pattern can be reduced through grayscale exposure input pattern calibration, resulting in high-fidelity three-dimensional exposure results.

[0141] Therefore, the surface plasmon grayscale lithography technology proposed in this application can greatly improve the exposure quality of three-dimensional micro-nano structures and has great practical applicability. Applying grayscale pattern exposure to maskless surface plasmon lithography technology is the main way to obtain high-resolution and high-fidelity three-dimensional micro-nano structures. This is of great significance for further research on the fabrication of low-cost, large-area, and high-quality three-dimensional micro-nano structures.

[0142] Figure 9 This paper illustrates a schematic diagram of a three-dimensional micro / nano structure fabrication apparatus based on a surface plasmonic grayscale lithography system, as provided in an embodiment of this application. Figure 9 As shown, the device includes:

[0143] The acquisition module 301 is used to acquire the spatial distribution characteristics of the field strength of the surface plasmon grayscale lithography system at the opening of the bow-shaped nanopore.

[0144] The first determining module 302 is used to determine the correspondence between the spatial distribution characteristics of the field strength and the size of the gap between the bow-shaped nanopores based on the spatial distribution characteristics of the field strength.

[0145] The second determining module 303 is used to perform grayscale control on the exposure dose of the surface plasma grayscale lithography system based on the correspondence between the field strength spatial distribution characteristics and the gap size, and to determine the grayscale exposure input pattern corresponding to the target three-dimensional micro-nano structure.

[0146] The third determining module 304 is used to input the grayscale exposure input pattern into the lithography imaging model and photoresist imaging model of the surface plasma grayscale lithography system for exposure processing, and to determine the pattern quality parameters corresponding to the exposure pattern.

[0147] In one possible implementation, the acquisition module includes:

[0148] The first acquisition submodule is used to acquire the point spread function of the surface plasmonic grayscale lithography system at the bow-shaped nano-aperture opening through simulation software;

[0149] The first determining submodule is used to determine the transverse field strength attenuation characteristics and the longitudinal field strength attenuation characteristics based on the point spread function.

[0150] In one possible implementation, the first determining module includes:

[0151] The second determining submodule is used to model and analyze the transverse field strength attenuation characteristics and longitudinal field strength attenuation characteristics corresponding to the opening of the bow nanopore, and to determine that there are size scaling behavior characteristics between the field strength distribution in the transverse and longitudinal directions and the gap of the bow nanopore.

[0152] In one possible implementation, the size scaling behavior is such that, regardless of the size of the gap between the bow nanopores, there is a strong field strength attenuation characteristic at the opening of the bow nanopores, and as the size of the exposed pattern feature of the bow nanopores decreases, the field strength attenuation characteristic becomes stronger but the attenuation trend remains unchanged.

[0153] In one possible implementation, the device further includes:

[0154] The second acquisition submodule is used to acquire the first photoresist contrast curve corresponding to the surface plasma grayscale lithography system and the second photoresist contrast curve corresponding to the conventional optical lithography system, respectively.

[0155] The third determining submodule is used to compare the first bandwidth of the first photoresist contrast curve and the second bandwidth of the second photoresist contrast curve, and determine that the first bandwidth is greater than the second bandwidth.

[0156] The fourth determining submodule is used to determine, when the first bandwidth is greater than the second bandwidth, that the controllability of the surface plasmonic grayscale lithography system for the required exposure dose per unit volume is higher than that of the conventional optical lithography system for the required exposure dose.

[0157] In one possible implementation, the second determining module includes:

[0158] The control submodule is used to control the exposure dose of the surface plasma grayscale lithography system by spatially controlling the pulse width of the light source laser, based on the correspondence between the spatial distribution characteristics of the field strength and the gap size.

[0159] The third acquisition submodule is used to acquire the calibration curve of grayscale exposure dose, exposure pattern depth and exposure pattern width corresponding to the grayscale adjustment.

[0160] The fifth determining submodule is used to determine the grayscale exposure input graphic corresponding to the target three-dimensional micro / nano structure based on the calibration curve.

[0161] In one possible implementation, the control submodule includes:

[0162] The first determining unit is used to determine the correspondence between the pulse response and the grayscale exposure dose by adding sub-pixels and applying continuous or discontinuous pulse response control to the sub-pixels based on the correspondence between the spatial distribution characteristics of the field strength and the gap size.

[0163] In one possible implementation, the third acquisition submodule includes:

[0164] The second determining unit is used to determine a calibration curve of the grayscale exposure dose, the exposure pattern depth, and the exposure pattern width based on the correspondence between the pulse response and the grayscale exposure dose.

[0165] In one possible implementation, the second acquisition submodule includes:

[0166] The first acquisition unit is used to acquire the first exposure result of the dot mapping pattern corresponding to the surface plasma grayscale lithography system in the photoresist;

[0167] The second acquisition unit is used to acquire the second exposure result of the dot mapping pattern corresponding to the photoresist in the conventional optical lithography system;

[0168] The third determining unit is used to determine the first photoresist contrast curve corresponding to the surface plasma grayscale lithography system in the longitudinal and transverse directions based on the first graphic feature size and the first exposure dose corresponding to the first exposure result.

[0169] The fourth determining unit is used to determine the second photoresist contrast curve corresponding to the conventional optical lithography system in the longitudinal and transverse directions based on the second pattern feature size and the second exposure dose corresponding to the second exposure result.

[0170] The three-dimensional micro / nano structure manufacturing apparatus based on a surface plasmon grayscale lithography system provided in this application embodiment can acquire the spatial distribution characteristics of the field intensity at the opening of the bow-shaped nanopores in the surface plasmon grayscale lithography system. Based on the spatial distribution characteristics of the field intensity, the correspondence between the spatial distribution characteristics of the field intensity and the size of the gap in the bow-shaped nanopores is determined. Based on the correspondence between the spatial distribution characteristics of the field intensity and the gap size, the exposure dose of the surface plasmon grayscale lithography system is grayscale controlled to determine the grayscale exposure input pattern corresponding to the target three-dimensional micro / nano structure. The grayscale exposure input pattern is then input into the surface plasmon grayscale lithography system. The system's photolithography imaging model and photoresist imaging model were used for exposure processing to determine the pattern quality parameters corresponding to the exposed pattern. Quantitative analysis of the unique near-field attenuation characteristics of surface plasmon lithography revealed a dimensional scaling behavior between the near-field attenuation characteristics of the plasma excited at the BNA opening and its gap size. Furthermore, a comparison of the photoresist contrast between surface plasmon lithography and traditional optical lithography systems showed that, due to the influence of near-field attenuation characteristics, surface plasmon lithography exhibits a wider photoresist contrast, meaning greater controllability of the required exposure dose per unit volume. In addition, the introduction of grayscale exposure input patterns is the physical essence of the surface plasmon lithography system's ability to fabricate three-dimensional micro / nano structures. By converting the target image input during exposure in a surface plasmon lithography system to grayscale, and by introducing the discontinuous distribution of sub-pixels and impulse responses, while simultaneously controlling the spatial distribution of the feature size of the target three-dimensional micro / nano structure and the required exposure dose, it is possible not only to obtain high-resolution multi-size three-dimensional micro / nano structures, but also to reduce the feature error between the exposed image and the target image through grayscale exposure input image calibration, thus obtaining high-fidelity three-dimensional exposure results. Therefore, the surface plasmon grayscale lithography technology proposed in this application can greatly improve the exposure quality of three-dimensional micro / nano structures and has significant practical applicability. Applying grayscale image exposure to maskless surface plasmon lithography technology is a major approach to obtaining high-resolution and high-fidelity three-dimensional micro / nano structures, which is of great significance for further research on low-cost, large-area, and high-quality three-dimensional micro / nano structure fabrication.

[0171] This application provides a three-dimensional micro / nano structure manufacturing device based on a surface plasma grayscale lithography system, which can achieve, for example... Figures 1 to 8 To avoid repetition, the methods for fabricating three-dimensional micro / nano structures based on surface plasmon grayscale lithography systems shown in any of the examples will not be described again here.

[0172] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, the disclosure, and the appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0173] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A method for manufacturing three-dimensional micro-nano structures based on a surface plasmon gray-scale lithography system, characterized in that, The method comprises: acquiring the field intensity spatial distribution characteristics of the surface plasmon gray-scale lithography system at the bowtie nano-aperture opening; determining the correspondence between the field intensity spatial distribution characteristics and the bowtie nano-aperture gap size based on the field intensity spatial distribution characteristics; gray-scale regulating and controlling the exposure dose of the surface plasmon gray-scale lithography system based on the correspondence between the field intensity spatial distribution characteristics and the gap size, to determine the gray-scale exposure input pattern corresponding to the target three-dimensional micro-nano structure; inputting the gray-scale exposure input pattern into the lithography imaging model and the photoresist imaging model of the surface plasmon gray-scale lithography system for exposure processing, to determine the pattern quality parameters corresponding to the exposure pattern.

2. The method of claim 1, wherein, The acquisition of the field intensity spatial distribution characteristics of the surface plasmon gray-scale lithography system at the bowtie nano-aperture opening comprises: acquiring the point spread function of the surface plasmon gray-scale lithography system at the bowtie nano-aperture opening through simulation software; determining the lateral field intensity decay characteristics and the longitudinal field intensity decay characteristics based on the point spread function.

3. The method of claim 2, wherein, The determination of the correspondence between the field intensity spatial distribution characteristics and the bowtie nano-aperture gap size based on the field intensity spatial distribution characteristics comprises: modeling and analyzing the corresponding lateral field intensity decay characteristics and longitudinal field intensity decay characteristics at the bowtie nano-aperture opening, to determine that the field intensity distribution in the lateral and longitudinal directions both has the size scaling behavior characteristics with the bowtie nano-aperture gap.

4. The method of claim 3, wherein, The size scaling behavior characteristics are that no matter how large the bowtie nano-aperture gap size is, there is a strong field intensity decay characteristic at the bowtie nano-aperture opening, and as the feature size of the bowtie nano-aperture exposure pattern continuously decreases, the field intensity decay characteristic becomes stronger but the decay trend remains unchanged.

5. The method of claim 1, wherein, After the determination of the correspondence between the field intensity spatial distribution characteristics and the bowtie nano-aperture gap size based on the field intensity spatial distribution characteristics, before the gray-scale regulating and controlling of the exposure dose of the surface plasmon gray-scale lithography system based on the correspondence between the field intensity spatial distribution characteristics and the gap size, to determine the gray-scale exposure input pattern corresponding to the target three-dimensional micro-nano structure, the method further comprises: respectively acquiring the first photoresist contrast curve corresponding to the surface plasmon gray-scale lithography system and the second photoresist contrast curve corresponding to the traditional optical lithography system; comparing the first bandwidth of the first photoresist contrast curve and the second bandwidth of the second photoresist contrast curve, to determine that the first bandwidth is greater than the second bandwidth; in the case that the first bandwidth is greater than the second bandwidth, determining that the regulatability of the required exposure dose of the surface plasmon gray-scale lithography system per unit volume is higher than the regulatability of the required exposure dose of the traditional optical lithography.

6. The method of claim 1, wherein, The gray-scale regulating and controlling of the exposure dose of the surface plasmon gray-scale lithography system based on the correspondence between the field intensity spatial distribution characteristics and the gap size, to determine the gray-scale exposure input pattern corresponding to the target three-dimensional micro-nano structure, comprises: Based on the corresponding relationship between the field intensity spatial distribution characteristics and the gap size, the gray-scale regulation of the exposure dose of the surface plasmon gray-scale lithography system is completed by spatial regulation of the pulse width of the light source laser. An alignment curve graph of the gray-scale exposure dose corresponding to the gray-scale regulation, and the exposure pattern depth and the exposure pattern width is obtained. Based on the alignment curve graph, the gray-scale exposure input pattern corresponding to the target three-dimensional micro-nano structure is determined.

7. The method of claim 6, wherein, The gray-scale regulation of the exposure dose of the surface plasmon gray-scale lithography system based on the corresponding relationship between the field intensity spatial distribution characteristics and the gap size includes: Based on the corresponding relationship between the field intensity spatial distribution characteristics and the gap size, the gray-scale exposure dose is divided into multiple levels by adding sub-pixels and applying continuous or non-continuous pulse response regulation to the sub-pixels, and the corresponding relationship between the pulse response and the gray-scale exposure dose is determined.

8. The method of claim 7, wherein, The alignment curve graph of the gray-scale exposure dose, and the exposure pattern depth and the exposure pattern width is obtained based on the corresponding relationship between the pulse response and the gray-scale exposure dose. The first photoresist contrast curve corresponding to the surface plasmon gray-scale lithography system and the second photoresist contrast curve corresponding to the traditional optical lithography system are obtained respectively, including:

9. The method of claim 5, wherein, A first exposure result of a point mapping pattern corresponding to the surface plasmon gray-scale lithography system in the photoresist is obtained. A second exposure result of a point mapping pattern corresponding to the traditional optical lithography system in the photoresist is obtained. Based on the first pattern feature size corresponding to the first exposure result and the first exposure dose, the first photoresist contrast curve corresponding to the surface plasmon gray-scale lithography system in the longitudinal and transverse directions is determined. Based on the second pattern feature size corresponding to the second exposure result and the second exposure dose, the second photoresist contrast curve corresponding to the traditional optical lithography system in the longitudinal and transverse directions is determined. The device includes:

10. A three-dimensional micro-nano structure manufacturing device based on a surface plasmon gray tone lithography system, characterized in that, An acquisition module is configured to acquire field intensity spatial distribution characteristics of a surface plasmon gray-scale lithography system at a bowtie nano-aperture opening. A first determination module is configured to determine a corresponding relationship between the field intensity spatial distribution characteristics and a bowtie nano-aperture gap size based on the field intensity spatial distribution characteristics. A second determination module is configured to perform gray-scale regulation of an exposure dose of the surface plasmon gray-scale lithography system based on the corresponding relationship between the field intensity spatial distribution characteristics and the gap size, and determine a gray-scale exposure input pattern corresponding to a target three-dimensional micro-nano structure. A third determination module is configured to input the gray-scale exposure input pattern to a lithography imaging model and a photoresist imaging model of the surface plasmon gray-scale lithography system for exposure processing, and determine a pattern quality parameter corresponding to an exposure pattern. ​

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