Grating exposure system and method

Abstract

The invention discloses a grating exposure system and method, and relates to the field of interference exposure, and the grating exposure system comprises a coherent light source module; a light beam adjusting module; a base; the detection module is used for detecting the interference fringes to form interference fringe real-time signals; the main control module is used for determining a light beam adjustment parameter according to a phase locking target value corresponding to the current exposure step in a target exposure strategy and the interference fringe real-time signal, and controlling the light beam adjustment module to adjust the optical path of the first coherent light beam and / or the second coherent light beam based on the light beam adjustment parameter so as to adjust the light path of the first coherent light beam and / or the second coherent light beam. The first coherent light beam and the second coherent light beam form interference fringes at a target position on the substrate. Therefore, the preparation of the complex and non-uniform special-shaped micro-nano structure can be realized, the preparation of the special-shaped micro-nano structure can be realized without adding other parts, the cost is low, and the structure of the grating exposure system is simple.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and more specifically, to a grating exposure system and method. Background Art

[0002] Traditional gratings are usually regular periodic structures, while shaped micro-nano structures have complex and non-uniform morphologies. The uniqueness of shaped micro-nano structures is that they can achieve highly customized control of light, including absorption, transmission, scattering, polarization conversion, etc. This makes shaped micro-nano structures show great potential in the fields of optical devices, sensors, photonic chips, surface enhanced Raman spectroscopy, etc. Through precise optical design and preparation processes, shaped micro-nano structures provide new possibilities for achieving efficient interaction between light and matter. However, as a micro-nanoscale structure with non-traditional shapes, the design and preparation of shaped micro-nano structures rely on advanced nano-processing technologies, such as electron beam lithography, ion beam etching, etc. However, technologies such as electron beam lithography and ion beam etching have problems such as low manufacturing efficiency and limited format. Summary of the invention

[0003] In view of the above problems, the present application proposes a grating exposure system and method.

[0004] In a first aspect, an embodiment of the present application provides a grating exposure system, which includes: a coherent light source module, which is used to output a first coherent light beam and a second coherent light beam; a beam adjustment module, which is arranged on the optical path of the first coherent light beam and the second coherent light beam; a base, which is used to place a substrate to be prepared as a micro-nano grating structure; a detection module, which is used to detect the first coherent light beam and the second coherent light beam, and convert the optical signals corresponding to the first coherent light beam and the second coherent light beam into real-time voltage signals; a main control module, which is used to control the base to rotate to a target angle, and determine beam adjustment parameters according to a phase-locked target voltage and the real-time voltage signal, and control the beam adjustment module to adjust the optical path of the first coherent light beam and / or the second coherent light beam based on the beam adjustment parameters, so that the first coherent light beam and the second coherent light beam after passing through the beam adjustment module form interference fringes at the target position on the substrate.

[0005] In a second aspect, an embodiment of the present application further provides a grating exposure method, which is applied to the aforementioned grating exposure system, and the method includes: outputting a first coherent light beam and a second coherent light beam through the coherent light source module; detecting the first coherent light beam and the second coherent light beam through the detection module, and converting the optical signals corresponding to the first coherent light beam and the second coherent light beam into real-time voltage signals; controlling the base to rotate to a target angle through the main control module, and determining beam adjustment parameters based on the phase-locked target voltage and the real-time voltage signal, and controlling the beam adjustment module to adjust the optical path of the first coherent light beam and / or the second coherent light beam based on the beam adjustment parameters, so that the first coherent light beam and the second coherent light beam after passing through the beam adjustment module form interference fringes at the target position on the substrate.

[0006] The grating exposure system provided by the present application, the coherent light source module in the grating exposure system outputs a first coherent light beam and a second coherent light beam; the detection module is used to detect the interference fringes and form a real-time interference fringes signal; the main control module determines the beam adjustment parameters according to the phase-locked target value corresponding to the current exposure step in the target exposure strategy and the real-time interference fringes signal, and based on the beam adjustment parameters, controls the beam adjustment module to adjust the optical path of the first coherent light beam and / or the second coherent light beam, so that the first coherent light beam and the second coherent light beam form interference fringes at the target position on the substrate. In this way, the preparation of complex and uneven special-shaped micro-nano structures can be realized, and a larger degree of control freedom is provided for the preparation of micro-nano grating structures, and the preparation of special-shaped micro-nano structures can be realized without adding other components, and the cost is low and the structure of the grating exposure system is simple. Furthermore, even if the interference fringes fluctuate due to factors such as optical platform vibration, temperature fluctuation, and airflow disturbance, the main control module can determine the corresponding beam adjustment parameters according to the real-time voltage signal, and based on the beam adjustment parameters, the position of the interference fringes can be reversely compensated and adjusted, so that the interference fringes remain relatively stable at the target position corresponding to the phase-locked target voltage, thereby achieving the locking of static interference fringes, and then making the morphology of the obtained micro-nano grating structure consistent with the actual required morphology, thereby improving the accuracy of the micro-nano grating structure manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0008] Figure 1A system architecture diagram of a grating exposure system provided by an embodiment of the present application is shown;

[0009] Figure 2 A system architecture diagram of a grating exposure system provided by another embodiment of the present application is shown;

[0010] Figure 3 A schematic diagram of the morphology of a micro-nano grating structure provided in an embodiment of the present application is shown;

[0011] Figure 4 A schematic diagram of interference fringes provided in an embodiment of the present application is shown;

[0012] Figure 5 A schematic diagram of another interference fringe provided in an embodiment of the present application is shown;

[0013] Figure 6 A schematic diagram of another interference fringe provided in an embodiment of the present application is shown;

[0014] Figure 7 A schematic diagram of the morphology of another micro-nano grating structure provided in an embodiment of the present application is shown;

[0015] Figure 8 A schematic diagram of interference fringes provided in an embodiment of the present application is shown;

[0016] Fig. 9 A schematic diagram of another interference fringe provided in an embodiment of the present application is shown;

[0017] Fig.10 A schematic diagram of another interference fringe provided in an embodiment of the present application is shown;

[0018] Fig.11 A schematic diagram of another interference fringe provided in an embodiment of the present application is shown;

[0019] Fig.12 A schematic diagram of the morphology of another micro-nano grating structure provided in an embodiment of the present application is shown;

[0020] Fig.13 A schematic diagram of another interference fringe provided in an embodiment of the present application is shown;

[0021] Fig.14 A schematic diagram of the morphology of another micro-nano grating structure provided in an embodiment of the present application is shown;

[0022] Fig.15 A system architecture diagram of a grating exposure system provided by another embodiment of the present application is shown;

[0023] Fig.16A schematic diagram of the morphology of another micro-nano grating structure provided in an embodiment of the present application is shown;

[0024] Fig.17 A schematic diagram of interference fringes provided in an embodiment of the present application is shown;

[0025] Fig.18 A schematic diagram of another interference fringe provided in an embodiment of the present application is shown;

[0026] Fig.19 A schematic diagram of another interference fringe provided in an embodiment of the present application is shown;

[0027] Fig. 20 A schematic diagram of another interference fringe provided in an embodiment of the present application is shown;

[0028] Fig.21 A schematic flow chart of a grating exposure method provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0030] In the description of the present invention, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In related technologies, traditional gratings are usually regular periodic structures, while shaped micro-nano structures have complex and non-uniform morphologies. The design and preparation of such structures rely on advanced nano-processing technologies, such as electron beam lithography and ion beam etching. The uniqueness of shaped micro-nano structures is that they can achieve highly customized control of light, including absorption, transmission, scattering, polarization conversion, etc. This makes shaped micro-nano structures show great potential in the fields of optical devices, sensors, photonic chips, surface enhanced Raman spectroscopy, etc. Through precise optical design and preparation processes, shaped micro-nano structures provide new possibilities for achieving efficient interaction between light and matter. However, as a micro-nanoscale structure with non-traditional shapes, shaped micro-nano structures also have problems such as low manufacturing efficiency and limited format.

[0033] Therefore, in order to overcome the above-mentioned defects, the embodiments of the present application provide a grating exposure system and method, which can improve the accuracy of manufacturing micro-nano grating structures, while improving the efficiency of large-area special-shaped micro-nano grating structures.

[0034] See also Figure 1 , Figure 1 1 is a schematic diagram of the system architecture of a grating exposure system 10 provided in an embodiment of the present application. The grating exposure system 100 includes: a coherent light source module 101, a beam adjustment module 102, a base 103, a detection module 104, a main control module 105 and an interference exposure component 106. Among them, the main control module 105 can establish communication connections with the beam adjustment module 102, the base 103 and the detection module 104 respectively, and the communication connection can be a wired connection or a wireless connection. The specific communication connection method can be set according to actual needs; the main control module and the beam adjustment module 102, the base 103 and the detection module 104 can exchange data through the established communication connection, and the exchanged data includes but is not limited to various types of data such as control signals and voltage signals, which are not limited in this embodiment.

[0035] The coherent light source module 101 is used to output a first coherent light beam and a second coherent light beam.

[0036] The beam adjustment module 102 is disposed on the optical path of the first coherent beam and the second coherent beam. The beam adjustment module 102 can adjust the optical path of the first coherent beam or the second coherent beam according to the beam adjustment parameters, or can adjust the optical paths of the first coherent beam and the second coherent beam at the same time according to the beam adjustment parameters.

[0037] The base 103 is used to place the substrate 20 to be prepared into a micro-nano grating structure.

[0038] The interference exposure component 106 is located on the optical paths of the first coherent light beam and the second coherent light beam. The first coherent light beam and the second coherent light beam are converged on the substrate 20 through the interference exposure component 106 to form interference fringes, that is, an interference exposure field is formed on the substrate 20.

[0039] Wherein, the surface of the substrate 20 is coated with a photosensitive material, and the photosensitive material can be a positive photoresist. After multiple interference exposures, the positive photoresist on the surface of the substrate 20 can be cleaned by a developer, and the exposed part is dissolved, and the unexposed part is left, so that the surface of the substrate forms an image of a micro-nano grating structure. Of course, the photosensitive material can also be a negative photoresist. After multiple interference exposures, the positive photoresist on the surface of the substrate 20 can be cleaned by a developer, and the unexposed part is dissolved, and the exposed part is left, so that the surface of the substrate can also form an image of a micro-nano grating structure. It can be understood that for substrates 20 coated with different types of photoresists, different interference exposure strategies need to be adopted to obtain the final desired micro-nano grating structure.

[0040] It is understandable that during the exposure process, disturbances in the external environment, including but not limited to vibrations of the optical platform, temperature fluctuations, airflow disturbances and other factors, will cause the interference fringes to move, that is, cause the phase of the interference fringes to change. In other words, the position of the interference fringes formed on the substrate 20 will be different from the pre-set position, and ultimately the micro-nano grating structure formed by the photosensitive material on the surface of the substrate 20 exposed by the interference fringes will be different from the micro-nano grating structure actually required.

[0041] The detection module 104 can be used to detect the interference fringes and form a real-time signal of the interference fringes. The detection module 140 can be a CCD camera (charge coupled device camera) or a photodiode (PD). A communication connection is established between the detection module 104 and the main control module 105, and the two parties can exchange data through the communication connection. For example, the detection module can send the real-time signal of the detected interference fringes to the main control module 105 through the communication connection.

[0042] Based on this, the main control module 105 can further determine the beam adjustment parameters according to the phase-locking target value corresponding to the current exposure step in the target exposure strategy and the interference fringe real-time signal, and control the beam adjustment module to adjust the optical path of the first coherent beam and / or the second coherent beam based on the beam adjustment parameters, so that the first coherent beam and the second coherent beam form interference fringes at the target position on the substrate; the target exposure strategy is an exposure strategy for preparing the micro-nano grating structure, and the target exposure strategy includes at least the number of exposures and multiple phase-locking target values, the multiple phase-locking target values ​​correspond to multiple exposure steps one by one, and at least one phase-locking target value among the multiple phase-locking target values ​​is different from the other phase-locking target values. In addition, the base 103 is automatically or manually controlled to rotate the target angle compared to the initial position, so that the substrate 20 on the base 103 is rotated to the required angle for interference exposure.

[0043] It can be understood that each exposure step in the multiple exposures performed on the substrate 20 will correspond to a phase-locking target value, and the phase-locking target values ​​in different exposure steps may be different.

[0044] In this embodiment, the phase-locking target value can be determined according to different requirements for preparing micro-nano grating structures, so that the preparation of complex, uneven and special-shaped micro-nano structures can be realized; at the same time, in one exposure step, even if the interference fringes fluctuate due to factors such as optical platform vibration, temperature fluctuation, airflow disturbance, etc., the corresponding beam adjustment parameters can be calculated to adjust the position of the interference fringes in reverse compensation, so that the interference fringes remain relatively stable at the target position corresponding to the phase-locking target voltage, thereby realizing the locking of static interference fringes, and at the same time improving the accuracy of the micro-nano grating structure obtained after a single exposure. In addition, different phase-locking target voltages required can be set in different exposure steps, so that after each exposure of the substrate, the required interference fringes are generated at different positions on the substrate, so as to obtain the micro-nano grating structure of the required morphology by superposition, that is, the micro-nano grating structure can be significantly changed only by the phase-locking target voltage, which provides a large degree of control freedom for the preparation of the micro-nano grating structure, and the preparation of special-shaped micro-nano structures can be realized without adding other components, and the cost is low and the structure of the grating exposure system is simple.

[0045] See also Figure 2 , Figure 21 is a schematic diagram of the structure of a grating exposure system 10 provided in another embodiment of the present application. The grating exposure system 10 includes: a coherent light source module 101, a beam adjustment module 102, a base 103, a detection module 104, a main control module 105 and an interference exposure component 106. The detection module 104 may include a first beam splitting element 1041, a second beam splitting element 1042, a beam combining element 1043 and a fringe detection unit 1044; the interference exposure component 106 may include: a first reflector 1061, a second reflector 1062, a first beam expander 10633, a second beam expander 1064, a first collimator 1065 and a second collimator 1066.

[0046] in, Figure 2 Only the optical path schematic diagram of the grating exposure system is shown, and the main control module 105 is not shown. Figure 2 As shown in the figure, of course, the main control module 105 is the same as the previous embodiment, and communication connections are established between the beam adjustment module 102, the base station 103 and the detection module 104 respectively.

[0047] Optionally, the coherent light source module 101 may include a laser 1011, a reflector 1012 and a third beam splitting element 1013; the laser light source 1011 is used to output a laser beam, the reflector 1012 is used to reflect the laser beam to the third beam splitting element 1013, and the third beam splitting element 1013 is used to split the laser beam and output the first coherent light beam and the second coherent light beam obtained by the splitting.

[0048] Optionally, the beam adjustment module 102 may specifically include a first micro-brake 1021 and a second micro-brake 1022, and the micro-brake may be a piezoelectric displacement stage. The first micro-brake 1021 is connected to the first reflector 1061 by a rigid body, and the first micro-brake 1021 is used to move according to the position movement parameter, thereby driving the first reflector 1061 to move together; the second micro-brake 1022 is connected to the first reflector 1062 by a rigid body, and the second micro-brake 1022 may also be used to move according to the position movement parameter, thereby driving the first reflector 1062 to move together. Of course, the beam adjustment module 102 may also include only the first micro-brake 1021 or the second micro-brake 1022, that is, only the first micro-brake 1021 acts on the first reflector 1061 to move the first reflector 1061, or only the second micro-brake 1022 acts on the second reflector 1062 to move the second reflector 1062.

[0049] After passing through the first beam expander 1063, the first collimator 1065 and the first reflector 1061, the first coherent light beam converges on the substrate 20 placed on the base 103; after passing through the second beam expander 1064, the second collimator 1066 and the first reflector 1062, the second coherent light beam also converges on the substrate 20 placed on the base 103; based on this, the first coherent light beam and the second coherent light beam converged on the surface of the substrate 20 can form interference fringes (i.e., interference exposure fields). In other words, the first coherent light beam and the second coherent light beam are irradiated on the substrate to achieve interference exposure of the substrate surface.

[0050] It is understandable that during the exposure process, disturbances in the external environment, including but not limited to vibrations of the optical platform, temperature fluctuations, airflow disturbances and other factors, will cause the interference fringes to move, that is, cause the phase of the interference fringes to change. In other words, the position of the interference fringes formed on the substrate 20 will be different from the pre-set position, and ultimately the micro-nano grating structure formed by the photosensitive material on the surface of the substrate 20 exposed by the interference fringes will be different from the micro-nano grating structure actually required.

[0051] Based on this, the present embodiment uses the fringe detection unit 1044 to detect in real time the first coherent light beam and the second coherent light beam used for interference exposure of the substrate 20, so that the position and light intensity of the interference fringes formed by the first coherent light beam and the second coherent light beam can be obtained according to the optical signals corresponding to the first coherent light beam and the second coherent light beam detected in real time. Specifically, after passing through the first reflector 1061, a part of the first coherent light beam is transmitted from the first beam splitter element 1041 to the substrate 20, and another part of the first coherent light beam (i.e., the first sub-coherent light beam) is reflected from the first beam splitter element 1041 to the beam combining element 1043; similarly, after passing through the reflector 1022, a part of the second coherent light beam is transmitted from the second beam splitter element 1042 to the substrate 20, and another part of the second coherent light beam (i.e., the second sub-coherent light beam) is reflected from the second beam splitter element 1042 to the beam combining element 1043. The suitable element 112 combines the first sub-coherent beam and the second sub-coherent beam and makes them incident on the fringe detection unit 1044 .

[0052] Further, after detecting the first sub-coherent light beam and the second sub-coherent light beam, the detection module 104 can convert the collected optical signal into an electrical signal, that is, into a real-time voltage signal, and send the real-time voltage signal to the main control module 105 based on the communication connection with the main control module 105. The main control module 105 receives the real-time voltage signal and determines the beam adjustment parameter according to the voltage change value between the real-time voltage signal and the phase-locked target voltage. In a specific embodiment, the relationship between the difference between the phase-locked target voltage and the real-time voltage signal and the position of the beam adjustment parameter can be represented by the following correlation function:

[0053] △I=sin(wx+(4πΔdcosθ) / λ)

[0054] Wherein, ΔI is the voltage change value, w=2π / T, x is the horizontal position of the detection module 104, Δd is the beam adjustment parameter, and λ is the coherent beam wavelength.

[0055] In this embodiment, the main control module 105 can determine the beam adjustment parameter according to the voltage change value between the real-time voltage signal and the phase-locked target voltage signal. The beam adjustment parameter can be the position movement parameter of the first reflector 1061. The main control module 105 is used to control the first microbrake 1023 to move according to the position movement parameter, thereby driving the first reflector to move, so as to change the beam difference between the first coherent light beam and the second coherent light beam, so that the first coherent light beam reflected on the substrate by the first reflector 1061 after movement and the second coherent light beam reflected on the substrate by the second reflector form interference fringes at the target position on the substrate. Of course, the first reflector 1062 can also be controlled to move. The principle of controlling the movement of the first reflector 1062 is similar to the principle of controlling the movement of the first reflector 1061, and this embodiment does not limit this.

[0056] In this way, in one exposure step, even if the interference fringes fluctuate due to factors such as optical platform vibration, temperature fluctuation, airflow disturbance, etc., the corresponding beam adjustment parameters can be calculated to perform reverse compensation adjustment on the position of the interference fringes, so that the interference fringes remain relatively stable at the target position corresponding to the phase-locked target voltage, thereby achieving the locking of static interference fringes, and thus improving the accuracy of the micro-nano grating structure obtained after each exposure; at the same time, in the process of preparing special-shaped micro-nano structures by multiple exposures, according to the preparation requirements of different special-shaped micro-nano structures, the formation position of the interference fringes on the substrate in different exposure steps can be changed by changing the phase-locked target signal, and the special-shaped micro-nano structure is formed by superposition after multiple exposures. There is no need to add other additional components to achieve different formation positions of the interference fringes on the substrate in different exposure steps. The grating exposure system has a simple structure and low cost.

[0057] It can be understood that, in order to prepare a special-shaped micro-nano grating structure on the surface of the substrate 20, it is generally necessary to perform multiple interference exposures, and the position of the interference fringes formed on the substrate 20 by each interference exposure needs to be different. In some embodiments, a target exposure strategy can be artificially formulated in advance according to the desired morphology of the micro-nano grating structure, and the target exposure strategy includes at least the number of exposures, the phase-locked target voltage in each exposure step, and the target angle, wherein the target angle is the angle value that the substrate 20 needs to rotate compared to the initial position. Further, before exposing the substrate 20, the pre-formulated target exposure strategy is input into the main control module 105 for storage, so that the main control module 105 controls the beam adjustment module and the base according to the exposure strategy, and performs multiple exposures on the substrate to form the interference fringes at multiple target positions on the substrate. That is, the fully automated adjustment of multiple exposure steps is realized, without manual participation, and the efficiency and accuracy of interference exposure are improved.

[0058] In other embodiments, the required morphology diagram of the micro-nano grating structure can be pre-input into the main control module 105, and the main control module 105 can automatically generate an exposure strategy according to the morphology diagram of the micro-nano grating structure, so that the main control module 105 controls the beam adjustment module and the base according to the exposure strategy generated by itself, and performs multiple exposures on the substrate to form the interference fringes at multiple target positions on the substrate. In this way, the full automation of the exposure strategy and the exposure steps is realized, which greatly improves the efficiency and accuracy of the preparation of the micro-nano grating structure.

[0059] Optionally, the number of exposures in the target exposure strategy is not limited, thereby facilitating the preparation of more complex micro-nano grating structures.

[0060] For example, for Figure 3 The morphology schematic diagram of the micro-nano grating structure shown in the figure, the target exposure strategy may include three exposures, the target angle in the first exposure step is 0 degrees (i.e., the initial position), and the target phase-locking voltage is V1; the target angle in the second exposure step is +90 degrees, and the target phase-locking voltage is also V1; the target angle in the third exposure step is still +90 degrees, and the target phase-locking voltage is V2.

[0061] Based on this, in the first exposure step, the angle of the substrate 20 is placed at the initial position, and the main control module 105 controls the absolute position of the interference fringes according to the target phase-locking voltage V1, so that the following can be obtained: Figure 4 The interference fringes shown. Figure 4 The grayscale portion in the graph represents the exposure dose on the substrate, and from black to white represents the exposure dose from low to high.

[0062] In the second exposure step, the main control module 105 can send a rotation control signal to the base 103 according to the target angle, so that the base 103 rotates 90 degrees clockwise compared to the initial position, that is, drives the substrate 20 to rotate 90 degrees clockwise, and for the substrate 20 after rotating 90 degrees, the absolute position of the interference fringes generated by the second exposure is controlled according to the target phase-locked voltage V1, so that the following can be superimposed. Figure 5 The interference fringes shown.

[0063] In the third exposure step, the substrate 20 is still placed in the same position as in the second exposure, but the main control module controls the absolute position of the interference fringes according to the target phase-locking voltage V2, that is, the interference fringes are displaced to a certain extent. At this time, the main control module 105 controls the movement of the first reflector 1061 or the first reflector 1062 according to the voltage change value between the target phase-locking voltage V2 and the target phase-locking voltage V1, thereby changing the optical path difference between the first coherent light beam and the second coherent light beam, so that the interference fringes generated by the third exposure have a phase shift of π / 4 compared to the interference fringes generated by the second exposure, thereby finally obtaining the following: Figure 6 The interference fringes shown. Wherein, the total exposure dose J1 of the first exposure = 2*the total exposure dose J2 of the second exposure = 3*the total exposure dose J3 of the third exposure.

[0064] Finally, the substrate 20 can be cleaned with a developer to convert the exposure dose distribution into a micro-nano structure distribution. According to the final total exposure dose distribution and the photoresist threshold curve, the final result is as follows: Figure 3 The micro-nano grating morphology is shown, where the black represents the photoresist remaining after cleaning, that is, the micro-nano grating structure.

[0065] For example, for Figure 7 The morphology schematic diagram of the micro-nano grating structure shown in the figure, the target exposure strategy may include 4 exposures, the target angle in the first exposure step is 0 degrees (i.e., the initial position), and the target phase-locking voltage is V1; the target angle in the second exposure step is 0 degrees, and the target phase-locking voltage is V2; the target angle in the third exposure step is still +60 degrees, and the target phase-locking voltage is V1; the target angle in the third exposure step is still -60 degrees, and the target phase-locking voltage is V3.

[0066] Based on this, in the first exposure step, the angle of the substrate 20 is placed at the initial position, and the main control module 105 controls the absolute position of the interference fringes according to the target phase-locked voltage V1, so as to obtain the initial interference fringes.

[0067] In the second exposure step, the substrate 20 is still placed in the same position as in the first exposure, but the main control module controls the absolute position of the interference fringes according to the target phase-locking voltage V2, that is, the interference fringes will be displaced to a certain extent. At this time, the main control module 105 controls the movement of the first reflector 1061 or the first reflector 1062 according to the voltage change value between the target phase-locking voltage V2 and the target phase-locking voltage V1, thereby changing the optical path difference between the first coherent light beam and the second coherent light beam, so that the interference fringes generated by the second exposure are phase-shifted by 3π / 4 compared to the interference fringes generated by the first exposure, thereby finally obtaining the following: Figure 8 The interference fringes shown.

[0068] In the third exposure step, the main control module 105 can send a rotation control signal to the base 103 according to the target angle, so that the base 103 rotates 60 degrees clockwise compared to the initial position, that is, drives the substrate 20 to rotate 60 degrees clockwise, and for the substrate 20 after rotating 60 degrees, the absolute position of the interference fringes generated by the third exposure is controlled according to the target phase-locked voltage V1, so that the following can be superimposed. Fig. 9 The interference fringes shown.

[0069] In the fourth exposure step, the main control module 105 can send a rotation control signal to the base 103 according to the target angle, so that the base 103 rotates 60 degrees counterclockwise compared to the initial position, that is, the substrate 20 is controlled to rotate 120 degrees counterclockwise compared to the position of the substrate 20 in the third exposure step, and for the substrate 20 rotated 120 degrees, the absolute position of the interference fringes generated by the third exposure is controlled according to the target phase-locking voltage V3, that is, the morphology of the final micro-nano grating structure is changed only by changing the phase shift of the target phase-locking voltage relative to V1. Specifically, the value of V3 can make the interference fringes generated under the phase-locking target voltage V3 shift by π / 4 compared to the interference fringes under the phase-locking target voltage V1, so that the following can be superimposed. Fig.10 The interference fringes shown in FIG. 1 , wherein the total dose of the first exposure J1 = the total dose of the second exposure J2 = 2*the total dose of the third exposure J3 = 2*the total dose of the fourth exposure J4.

[0070] Finally, the substrate 20 is cleaned with a developer, and the exposure dose distribution is converted into a micro-nano structure distribution. According to the final total exposure dose distribution, combined with the photoresist threshold curve, the following can be obtained: Figure 7 The micro-nano grating morphology shown, where the black represents the photoresist remaining after cleaning, i.e. the micro-nano grating structure.

[0071] Optionally, in this example, the phase-locked target voltage in the fourth exposure step can also be set to enable the interference fringes generated under the phase-locked target voltage V3 to be phase-shifted by π / 2 compared to the interference fringes under the phase-locked target voltage V1, so that the following can be obtained by superposition: Fig.11 Based on the total exposure dose distribution, combined with the photoresist threshold curve, and using the developer to clean the substrate 20, it can be obtained Fig.12 The micro-nano grating structure shown.

[0072] Optionally, in this example, the phase-locked target voltage in the fourth exposure step can also be set to enable the interference fringes generated under the phase-locked target voltage V3 to be phase-shifted by 3π / 4 compared to the interference fringes under the phase-locked target voltage V1, so that the following can be obtained by superposition: Fig.13 Based on the total exposure dose distribution, combined with the photoresist threshold curve, and using the developer to clean the substrate 20, it can be obtained Fig.14 The micro-nano grating structure shown.

[0073] In this embodiment, combined with Figure 7 , Fig.12 as well as Fig.14 The three types of micro-nano grating structures with obvious differences shown can be known that by setting different phase-locked target voltages required for each exposure step through the grating exposure system 10, after each exposure of the substrate, the required interference fringes are generated at different positions on the substrate, so as to obtain the micro-nano grating structure of the required morphology by superposition, that is, the micro-nano grating structure can be significantly changed only by the phase-locked target voltage, which provides a greater degree of control freedom for the preparation of the micro-nano grating structure. In particular, unlike the electron beam direct writing lithography method, which requires etching of the special-shaped grating one by one, the present embodiment can simultaneously etch the required special-shaped micro-nano structure in one format, and the processing efficiency is high. At the same time, the grating exposure system 10 can also solve the interference fringe fluctuations caused by factors such as optical platform vibration, temperature fluctuations, and airflow disturbances. By calculating the corresponding beam adjustment parameters, the position of the interference fringes is reversely compensated and adjusted, so that the interference fringes remain relatively stable at the target position corresponding to the phase-locked target voltage, thereby achieving the locking of static interference fringes, and then improving the accuracy of the micro-nano grating structure obtained after multiple exposures.

[0074] See also Fig.15 , Fig.151 is a schematic diagram of the structure of a grating exposure system 10 provided in another embodiment of the present application. The grating exposure system 10 includes: a coherent light source module 101, a beam adjustment module 102, a base 103, a detection module 104, a main control module 105, an interference exposure component 106 and a reflective grating 107. The interference exposure component 106 may include: a first reflector 1061, a second reflector 1062, a first beam expander 10633, a second beam expander 1064, a first collimator 1065 and a second collimator 1066.

[0075] in, Figure 3 Only the optical path schematic diagram of the grating exposure system is shown, and the main control module 105 is not shown. Figure 3 As shown in the figure, of course, the main control module 105 is the same as the previous embodiment, and communication connections are established between the beam adjustment module 102, the base station 103 and the detection module 104 respectively.

[0076] Optionally, the coherent light source module 101 may include a laser 1011, a reflector 1012 and a third beam splitting element 1013; the laser light source 1011 is used to output a laser beam, the reflector 1012 is used to reflect the laser beam to the third beam splitting element 1013, and the third beam splitting element 1013 is used to split the laser beam and output the first coherent light beam and the second coherent light beam obtained by the splitting.

[0077] The beam adjustment module 102 includes a first acousto-optic modulator 1021, a second acousto-optic modulator 1022, a first aperture 1023 and a second aperture 1024. The first acousto-optic modulator 1021 is arranged on the optical path of the first coherent light beam, and the second acousto-optic modulator 1022 is arranged on the optical path of the second coherent light beam; the first aperture 1023 is arranged at the light exit of the first acousto-optic modulator 1021, and the second aperture 1024 is arranged at the light exit of the second acousto-optic modulator 1022.

[0078] The first aperture 1023 is used to pass the first order diffracted beam corresponding to the first coherent beam output by the first acousto-optic modulator 1021, and to block the other order diffracted beams output by the first acousto-optic modulator 1021 except the first order diffracted beam. The second aperture 1024 is used to pass the first order diffracted beam corresponding to the second coherent beam output by the second acousto-optic modulator 1022, and to block the other order diffracted beams output by the second acousto-optic modulator 1022 except the first order diffracted beam, so as to avoid the generation of ambient light and the interference with the grating interference exposure.

[0079] After passing through the first acousto-optic modulator 1021, the first beam expander 1063, the first collimator 1065 and the first reflector 1061, the first coherent light beam converges on the substrate 20 placed on the base 103; after passing through the second acousto-optic modulator 1022, the second beam expander 1064, the second collimator 1066 and the second reflector 1062, the second coherent light beam also converges on the substrate 20 placed on the base 103; based on this, the first coherent light beam and the second coherent light beam converged on the surface of the substrate 20 can form interference fringes (i.e., interference exposure fields). In other words, the first coherent light beam and the second coherent light beam are irradiated on the substrate to achieve interference exposure of the substrate surface.

[0080] Further, in this embodiment, the first coherent light beam and the second coherent light beam used for interference exposure of the substrate 20 are detected in real time by the detection module 104, so that the position and light intensity of the interference fringes formed by the first coherent light beam and the second coherent light beam can be obtained according to the optical signals corresponding to the first coherent light beam and the second coherent light beam detected in real time. Specifically, the grating exposure system also includes a reflection grating 107, which is used to be arranged on the substrate 20. After a part of the first coherent light beam passes through the first reflector 1061, it is incident on the substrate 20, and another part of the first coherent light beam (i.e., the first sub-coherent light beam) passes through the first reflector 1061 and is incident on the reflection grating 107 on the substrate 20; similarly, after a part of the second coherent light beam passes through the second reflector 1062, it is incident on the substrate 20, and after another part of the second coherent light beam (i.e., the second sub-coherent light beam) passes through the second reflector 1062, it is also incident on the reflection grating 107 on the substrate 20. The reflection grating 107 combines the first sub-coherent beam and the second sub-coherent beam and reflects them to the detection module 104 .

[0081] After detecting the first sub-coherent light beam and the second sub-coherent light beam, the detection module 104 can convert the collected optical signal into an electrical signal, that is, into a real-time voltage signal, and send the real-time voltage signal to the main control module 105 based on the communication connection with the main control module 105. The main control module 105 receives the real-time voltage signal, and determines the phase shift of the interference fringes according to the voltage change value between the real-time voltage signal and the phase-locked target voltage, and determines the beam adjustment parameters according to the phase shift. Among them, the phase shift of the interference fringes can still be determined according to the voltage change value based on the correlation function mentioned in the above embodiment, which will not be repeated here.

[0082] In this embodiment, the beam adjustment parameters include a first carrier drive signal for the first AOM 1021 and a second carrier drive signal for the second AOM 1022. The main control module 105 sends a first carrier drive signal to the first AOM 1021 and sends a second carrier drive signal to the second AOM 1022 to adjust the frequency of the first coherent light beam after passing through the first AOM 1021 and the frequency of the second coherent light beam after passing through the second AOM 1022. The frequency of the laser 1011 is f0, and the first AOM 1021 can be a fixed-frequency AOM with a fixed frequency shift of fc, that is, after passing through the first AOM 1021, the frequency of the first-order diffracted light beam generated becomes f1=f0+fc. Correspondingly, the second AOM 1021 is also a fixed-frequency AOM with a fixed frequency shift of fc.

[0083] For example, if the interference fringes need to be phase-shifted by △f, a first carrier driving signal with a frequency of fc+△f can be applied to the first acousto-optic modulator 1021, so that the frequency of the first-order diffraction beam output by the first acousto-optic modulator 1021 becomes f2=f0+fc+△f, and the phase of the interference fringes can be regulated; of course, the second acousto-optic modulator 1022 is similar, and will not be described here. In this way, the frequency of the interference beam is directly changed by the acousto-optic modulator, thereby changing the phase of the interference fringes, and finally changing the absolute position of the interference fringes on the substrate 20.

[0084] For example, for Fig.16 The morphology schematic diagram of the micro-nano grating structure shown in the figure, the exposure strategy may include 5 exposures, the target angle in the first exposure step is 0 degrees (i.e., the initial position), and the target phase-locking voltage is V1; the target angle in the second exposure step is 0 degrees, and the target phase-locking voltage is V2; the target angle in the third exposure step is +60 degrees, and the target phase-locking voltage is V1; the target angle in the fourth exposure step is -60 degrees, and the target phase-locking voltage is V1; the target angle in the fifth exposure step is -60 degrees, and the target phase-locking voltage is V1.

[0085] Based on this, in the first exposure step, the angle of the substrate 20 is placed at the initial position, and the main control module 105 controls the absolute position of the interference fringes according to the target phase-locked voltage V1, so as to obtain the initial interference fringes.

[0086] In the second exposure step, the angle of the substrate 20 is placed at the initial position, but at this time the main control module 105 controls the absolute position of the interference fringes according to the target phase-locking voltage V2, that is, the interference fringes will be displaced to a certain extent. At this time, the main control module 105 will control the first acousto-optic modulator 1021 and the second acousto-optic modulator 1022 to change the frequency of the first coherent light beam and the second coherent light beam according to the voltage change value between the target phase-locking voltage V2 and the target phase-locking voltage V1, thereby changing the optical path difference between the first coherent light beam and the second coherent light beam, so that the interference fringes generated by the second exposure have a phase shift of 3π / 4 compared to the initial interference fringes generated by the first exposure, so as to finally obtain the following: Fig.17 The interference fringes shown. Fig.17 The grayscale portion in the graph represents the exposure dose on the substrate, and from black to white represents the exposure dose from low to high.

[0087] In the third exposure step, the main control module 105 can send a rotation control signal to the base 103 according to the target angle, so that the base 103 rotates 60 degrees clockwise compared to the initial position, that is, drives the substrate 20 to rotate 60 degrees clockwise, and for the substrate 20 rotated 90 degrees, the absolute position of the interference fringes generated by the third exposure is controlled according to the target phase-locked voltage V1, so that the following can be superimposed. Fig.18 The interference fringes shown.

[0088] In the fourth exposure step, the main control module 105 can send a rotation control signal to the base 103 according to the target angle, so that the base 103 rotates 60 degrees counterclockwise compared to the initial position, that is, the substrate 20 is driven to rotate 120 degrees counterclockwise compared to the position in the third exposure step; and for the rotated substrate 20, the absolute position of the interference fringes generated by the fourth exposure is controlled according to the target phase-locked voltage V1, so that the following can be superimposed. Fig.19 The interference fringes shown.

[0089] In the fifth exposure step, the substrate 20 is still placed in the same position as in the fourth exposure, but the main control module controls the absolute position of the interference fringes according to the target phase-locking voltage V2, that is, the interference fringes will be displaced to a certain extent. At this time, the main control module 105 controls the first acousto-optic modulator 1021 and the second acousto-optic modulator 1022 to change the frequencies of the first coherent light beam and the second coherent light beam according to the voltage change value between the target phase-locking voltage V2 and the target phase-locking voltage V1, thereby changing the optical path difference between the first coherent light beam and the second coherent light beam, so that the interference fringes generated by the fifth exposure have a certain phase shift, thereby finally obtaining the following: Fig. 20The interference fringes shown. Among them, 2*total exposure dose J1 of the first exposure = 2*total exposure dose J2 of the second exposure = total exposure dose J3 of the third exposure = 2*total exposure dose J4 of the fourth exposure = 2*total exposure dose J5 of the fifth exposure.

[0090] Finally, the substrate 20 can be cleaned with a developer to convert the exposure dose distribution into a micro-nano structure distribution. According to the final total exposure dose distribution and the photoresist threshold curve, the final result is as follows: Fig.16 The micro-nano grating morphology is shown, where the black represents the photoresist remaining after cleaning, that is, the micro-nano grating structure.

[0091] In this embodiment, through the grating exposure system 10, by setting different phase-locked target voltages required for each exposure step, after each exposure of the substrate, the required interference fringes are generated at different positions on the substrate, so as to obtain the micro-nano grating structure of the required morphology by superposition, that is, the micro-nano grating structure can be significantly changed only by the phase-locked target voltage, which provides a greater degree of control freedom for the preparation of the micro-nano grating structure. At the same time, the grating exposure system 10 can also solve the interference fringes fluctuations caused by factors such as optical platform vibration, temperature fluctuations, and airflow disturbances. By calculating the corresponding beam adjustment parameters, the position of the interference fringes is reversely compensated and adjusted, so that the interference fringes remain relatively stable at the target position corresponding to the phase-locked target voltage, thereby achieving the locking of static interference fringes, and then improving the accuracy of the micro-nano grating structure obtained after multiple exposures.

[0092] See also Fig.21 , Fig.21 1 is a flow chart of a grating exposure method provided in an embodiment of the present application, which is applied to the grating exposure system mentioned in any of the above embodiments. Fig.21 The grating exposure method provided in the embodiment of the present application is described in detail. The grating exposure method may include the following steps:

[0093] Step S410: outputting a first coherent light beam and a second coherent light beam through the coherent light source module.

[0094] Step S420: The first coherent light beam and the second coherent light beam are converged on a substrate through the interference exposure component to form interference fringes. The substrate is a substrate to be prepared as a micro-nano grating structure placed on a base.

[0095] Step S430: Detect interference fringes generated by the interference of the first coherent light beam and the second coherent light beam through the detection module to form a real-time interference fringes signal.

[0096] Step S440: The main control module determines the beam adjustment parameters according to the phase-locked target signal corresponding to the current exposure step in the target exposure strategy and the interference fringe real-time signal, and controls the beam adjustment module to adjust the optical path of the first coherent light beam and / or the second coherent light beam based on the beam adjustment parameters, so that the first coherent light beam and the second coherent light beam form interference fringes at the target position on the substrate. The target exposure strategy is an exposure strategy for preparing the micro-nano grating structure. The target exposure strategy includes at least the number of exposures and multiple phase-locked target values. The multiple phase-locked target values ​​correspond one-to-one to the multiple exposure steps, and at least one phase-locked target value among the multiple phase-locked target values ​​is different from the other phase-locked target values.

[0097] In this embodiment, the specific implementation of step S410 to step S440 can refer to the content of the above-mentioned embodiment, which will not be repeated here.

[0098] In this embodiment, different phase-locked target voltages required for each exposure step are set through the grating exposure system. After each exposure of the substrate, the required interference fringes are generated at different positions on the substrate, so as to obtain the micro-nano grating structure of the required morphology by superposition, that is, the micro-nano grating structure can be significantly changed only by the phase-locked target voltage, which provides a greater degree of control freedom for the preparation of the micro-nano grating structure. At the same time, the grating exposure system 10 can also solve the interference fringes fluctuations caused by factors such as optical platform vibration, temperature fluctuations, and airflow disturbances. By calculating the corresponding beam adjustment parameters, the position of the interference fringes is reversely compensated and adjusted, so that the interference fringes remain relatively stable at the target position corresponding to the phase-locked target voltage, thereby achieving the locking of static interference fringes, thereby improving the accuracy of the micro-nano grating structure obtained after multiple exposures.

Claims

1. A grating exposure system, characterized in that: The grating exposure system comprises: A coherent light source module, used for outputting a first coherent light beam and a second coherent light beam; A base, the base being used to place a substrate to be prepared into a micro-nano grating structure; An interference exposure component, wherein the interference exposure component is located on the optical path of the first coherent light beam and the second coherent light beam, and the first coherent light beam and the second coherent light beam are converged on the substrate through the interference exposure component to form interference fringes; A beam adjustment module, arranged on the optical paths of the first coherent light beam and the second coherent light beam; A detection module, used to detect the interference fringes and form a real-time interference fringes signal; The main control module determines the beam adjustment parameters according to the phase-locked target value corresponding to the current exposure step in the target exposure strategy and the interference fringe real-time signal, and controls the beam adjustment module to adjust the optical path of the first coherent beam and / or the second coherent beam based on the beam adjustment parameters so that the first coherent beam and the second coherent beam form interference fringes at the target position on the substrate.

2. The grating exposure system according to claim 1, characterized in that: The interference fringe real-time signal includes a real-time voltage signal, the phase-locking target value includes a phase-locking target voltage, and the main control module is used to determine the beam adjustment parameter according to a voltage change value between the real-time voltage signal and the phase-locking target voltage.

3. The grating exposure system according to claim 1, characterized in that: The interference exposure assembly includes a first reflector and a second reflector, wherein the first reflector is disposed on the optical path of the first coherent light beam and is used to reflect the first coherent light beam onto the substrate, and the second reflector is disposed on the optical path of the second coherent light beam and is used to reflect the second coherent light beam onto the substrate; The beam adjustment module is connected to the first reflector and / or the second reflector, and the beam adjustment module acts on the first reflector and / or the second reflector to move the first reflector and / or the second reflector; The beam adjustment parameters are position movement parameters of the first reflector and / or the second reflector, and the main control module is used to control the beam adjustment according to the position movement parameters to move the first reflector and / or the second reflector a preset distance, so that the first coherent light beam reflected by the first reflector to the substrate and the second coherent light beam reflected by the second reflector to the substrate form interference fringes at the target position on the substrate.

4. The grating exposure system according to claim 1, characterized in that: The detection module includes a first beam splitting element, a second beam splitting element, a beam combining element and a fringe detection unit; The first beam splitting element is used to reflect a first sub-coherent beam to the beam combining element, wherein the first sub-coherent beam is a partially coherent beam in the first coherent beam; The second beam splitting element is used to reflect a second sub-coherent beam to the beam combining element, wherein the second sub-coherent beam is a partially coherent beam in the second coherent beam; The beam combining element is used to combine the first sub-coherent light beam and the second sub-coherent light beam to generate interference fringes, so that the fringe detection unit can detect the interference fringes.

5. The grating exposure system according to claim 1, wherein the beam adjustment module comprises a first acousto-optic modulator and a second acousto-optic modulator, wherein the first acousto-optic modulator is arranged on the optical path of the first coherent light beam, and the second acousto-optic modulator is arranged on the optical path of the second coherent light beam; The beam adjustment parameters include a first carrier drive signal for the first acousto-optic modulator and a second carrier drive signal for the second acousto-optic modulator. The main control module is used to adjust the frequency of the first coherent light beam after passing through the first acousto-optic modulator based on the first carrier drive signal, and to adjust the frequency of the second coherent light beam after passing through the second acousto-optic modulator based on the second carrier drive signal, so that the first coherent light beam and the second coherent light beam after adjusting the frequency form the interference fringes at the target position on the substrate.

6. The grating exposure system according to claim 5, characterized in that: The beam adjustment module further includes a first aperture and a second aperture, wherein the first aperture is arranged at the light exit of the first acousto-optic modulator, and the second aperture is arranged at the light exit of the second acousto-optic modulator; The first aperture is used to pass a first-order diffracted light beam corresponding to the first coherent light beam output by the first acousto-optic modulator, and to block other-order diffracted light beams output by the first acousto-optic modulator except the first-order diffracted light beam; The second aperture is used to pass the first-order diffraction beam corresponding to the second coherent light beam output by the second acousto-optic modulator, and to block other-order diffraction beams output by the second acousto-optic modulator except the first-order diffraction beam.

7. The grating exposure system according to claim 1 further comprises a reflection grating, wherein the reflection grating is used to be arranged on the substrate, and the reflection grating is used to reflect the first coherent light beam and the second coherent light beam to the detection module so that the detection module detects the real-time signal of the interference fringe.

8. The grating exposure system according to claim 1, characterized in that: The target exposure strategy is an exposure strategy for preparing the micro-nano grating structure. The target exposure strategy includes at least the number of exposures and multiple phase-locking target values. The multiple phase-locking target values ​​correspond one-to-one to the multiple exposure steps, and at least one phase-locking target value among the multiple phase-locking target values ​​is different from the other phase-locking target values.

9. The grating exposure system according to any one of claims 1 to 7, characterized in that: The main control module is used to generate a target exposure strategy for the substrate according to the micro-nano grating structure, wherein the target exposure strategy at least includes the number of exposures, the phase-locked target value in each exposure step, and the target angle of rotation of the base; The main control module is used to control the beam adjustment module and the base platform according to the target exposure strategy to perform multiple exposures on the substrate to form the interference fringes at multiple target positions on the substrate.

10. The grating exposure system according to any one of claims 1 to 7, characterized in that: The coherent light source module includes a laser light source, a reflector and a third beam splitting element. The laser light source is used to output a laser light beam. The reflector is used to reflect the laser light beam to the third beam splitting element. The third beam splitting element is used to split the laser light beam and output the first coherent light beam and the second coherent light beam obtained by the splitting.

11. A grating exposure method, characterized in that: Applied to the grating exposure system according to any one of claims 1 to 10, the method comprises: Outputting a first coherent light beam and a second coherent light beam through the coherent light source module; The first coherent light beam and the second coherent light beam are converged on a substrate by the interference exposure component to form interference fringes, and the substrate is a substrate to be prepared as a micro-nano grating structure placed on a base; Detecting interference fringes generated by the interference of the first coherent light beam and the second coherent light beam through the detection module to form a real-time interference fringes signal; The main control module determines the beam adjustment parameters according to the phase-locked target signal corresponding to the current exposure step in the target exposure strategy and the interference fringe real-time signal, and controls the beam adjustment module to adjust the optical path of the first coherent light beam and / or the second coherent light beam based on the beam adjustment parameters, so that the first coherent light beam and the second coherent light beam form interference fringes at the target position on the substrate. The target exposure strategy is an exposure strategy for preparing the micro-nano grating structure. The target exposure strategy includes at least the number of exposures and multiple phase-locked target values. The multiple phase-locked target values ​​correspond one-to-one to the multiple exposure steps, and at least one phase-locked target value among the multiple phase-locked target values ​​is different from the other phase-locked target values.

Images