Double-beam exposure light path system with adjustable period
By introducing adjustable reflection and orientation adjustment units into the dual-beam exposure optical path system, the problem of inconvenient exposure period adjustment was solved, enabling the fabrication of diffraction gratings with multiple grating periods and improving light energy utilization and exposure field uniformity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- BEIJING GREATAR TECH CO LTD
- Filing Date
- 2025-05-07
- Publication Date
- 2026-04-17
AI Technical Summary
Existing dual-beam exposure optical path systems have difficulty adjusting the exposure period, making it difficult to fabricate diffraction gratings with multiple different grating periods under the same optical path setup.
By introducing an adjustable reflection unit and a direction adjustment unit into the dual-beam exposure optical path system, the angle between the first incident beam and the second incident beam and the substrate to be exposed can be changed, thereby achieving adjustment of the exposure cycle.
The fabrication of diffraction gratings with multiple different grating periods was achieved under the same optical path, improving the light energy utilization and the uniformity of the exposure field.
Smart Images
Figure CN224137616U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of grating exposure technology, specifically relating to an adjustable period dual-beam exposure optical path system. Background Technology
[0002] A diffraction grating is an optical element with a periodic microstructure or refractive index modulation, which has functions such as beam splitting, dispersion, phase matching, and polarization modulation. The period of the grating is generally in the range of hundreds of nanometers to tens of micrometers. The size of the grating, the diffraction efficiency and uniformity, stray light, and other parameters are used as evaluation criteria to affect the performance indicators of the grating.
[0003] The main fabrication methods for diffraction gratings include mechanical scribing, electron beam direct writing, X-ray lithography, and holographic ion beam etching. Holographic ion beam etching utilizes a holographic exposure system to perform interference exposure on a substrate coated with photoresist. After development, a photoresist grating mask is deposited on the substrate. Then, an ion beam etching machine is used to etch the substrate with the photoresist grating mask, completing the fabrication of the diffraction grating. Holographic ion beam etching has advantages such as low cost, controllable groove shape, and no ghost lines, and is currently widely used in the fabrication of diffraction gratings.
[0004] The most common holographic exposure systems are Loewe mirror exposure systems and dual-beam exposure optical path systems.
[0005] Due to the influence of the Loe mirror area, when the Loe mirror exposure system is used to expose diffraction gratings with a large period (e.g., a grating period greater than 450 nm), the exposure field area is small and the light field width will be less than half the width of the Loe mirror. The larger the period of the diffraction grating, the smaller the light field width, which is not conducive to the fabrication of large-area diffraction gratings.
[0006] The dual-beam exposure optical path system has advantages such as high stability, large exposure field area, high light intensity uniformity, low stray light, and no ghosting. However, the exposure period of the dual-beam exposure optical path system is determined by the angle between the two beams. Once the optical path is set up, exposure operations can only be performed with a fixed exposure period, making exposure period adjustment inconvenient. This makes it difficult to utilize the same optical path of the dual-beam exposure optical path system to perform exposure work in the fabrication process of diffraction gratings with various different grating periods. Utility Model Content
[0007] In order to overcome the shortcomings of the prior art, this utility model provides an adjustable period dual-beam exposure optical path system.
[0008] This utility model is achieved through the following technical solution:
[0009] This invention provides an adjustable period dual-beam exposure optical path system, including a light-emitting unit, a beam-splitting unit, a first beam-expanding and collimating unit, a second beam-expanding and collimating unit, a first reflection unit, and a second reflection unit;
[0010] The emitted beam from the light-emitting unit is split into a first beam and a second beam by the beam-splitting unit. The first beam becomes a first parallel beam after passing through a first beam-expanding and collimating unit. The first parallel beam is reflected by a first reflection unit that is rotated and adjusted, and then becomes the first incident beam that enters the substrate to be exposed. The second beam becomes a second parallel beam after passing through a second beam-expanding and collimating unit. The second parallel beam is reflected by a second reflection unit that is rotated and adjusted, and then becomes the second incident beam that enters the substrate to be exposed. The first incident beam and the second incident beam perform interference exposure on the substrate to be exposed.
[0011] The angle between the first incident beam and the second incident beam corresponds to the exposure cycle of the substrate to be exposed.
[0012] Furthermore, it also includes a first direction adjustment unit and a second direction adjustment unit;
[0013] The first direction adjustment unit is disposed at the bottom of the first reflective unit, and the second direction adjustment unit is disposed at the bottom of the second reflective unit.
[0014] Furthermore, the first orientation adjustment unit includes a first rotary table and a first pitch table, and the second orientation adjustment unit includes a second rotary table and a second pitch table;
[0015] The top of the first pitch stage is connected to the first reflective unit, and the bottom of the first pitch stage is connected to the first rotary stage.
[0016] The top of the second pitch stage is connected to the second reflector unit, and the bottom of the second pitch stage is connected to the second rotary stage.
[0017] Furthermore, the reflectivity of the first reflective unit is greater than 90%, and the reflectivity of the second reflective unit is greater than 90%.
[0018] Furthermore, the first beam expanding and collimating unit includes a first microscope objective, a first pinhole, and a first collimating lens; the first microscope objective is close to the beam splitting unit, the first collimating lens is close to the first reflecting unit, and the first pinhole is located at the focusing position of the first microscope objective.
[0019] The second beam expanding and collimating unit includes a second microscope objective, a second pinhole, and a second collimating lens; the second microscope objective is located near the beam splitting unit, the second collimating lens is located near the second reflection unit, and the second pinhole is located at the focusing position of the second microscope objective.
[0020] Furthermore, the area of the first reflecting unit is not greater than the exit aperture size of the first collimating lens, and the area of the second reflecting unit is not greater than the exit aperture size of the second collimating lens.
[0021] Furthermore, the center of the first reflecting unit and the center of the first collimating lens are located on the same horizontal line, and the center of the second reflecting unit and the center of the second collimating lens are located on the same horizontal line.
[0022] Furthermore, it also includes a third reflection unit, a fourth reflection unit, a fifth reflection unit, and a sixth reflection unit;
[0023] The third reflection unit is disposed on the transmission optical path between the light-emitting unit and the beam-splitting unit;
[0024] The fourth and fifth reflection units are disposed on the transmission optical path between the beam splitting unit and the first beam expanding and collimating unit, with the fourth reflection unit being close to the beam splitting unit.
[0025] The sixth reflection unit is disposed on the transmission optical path between the beam splitting unit and the second beam expanding and collimating unit.
[0026] Furthermore, the beam splitting unit employs a PBS beam splitter prism.
[0027] Furthermore, it also includes a first polarization adjustment unit and a second polarization adjustment unit;
[0028] The first polarization adjustment unit is disposed on the transmission optical path between the third reflection unit and the beam splitter unit, and the second polarization adjustment unit is disposed on the transmission optical path between the beam splitter unit and the fourth reflection unit.
[0029] Compared with the prior art, the technical solution of this utility model has the following beneficial effects:
[0030] This invention provides an adjustable-period dual-beam exposure optical path system, including a light-emitting unit, a beam-splitting unit, a first beam-expanding and collimating unit, a second beam-expanding and collimating unit, a first reflection unit, and a second reflection unit. The emitted beam from the light-emitting unit is split into a first beam and a second beam by the beam-splitting unit. The first beam, after passing through the first beam-expanding and collimating unit to become a first parallel beam, is reflected by the first reflection unit (which is adjusted by rotation) and then becomes the first incident beam, incident on the substrate to be exposed. The second beam, after passing through the second beam-expanding and collimating unit to become a second parallel beam, is reflected by the second reflection unit (which is adjusted by rotation) and then becomes the second incident beam, incident on the substrate to be exposed. The first and second incident beams interfere with each other during exposure of the substrate. The angle between the first and second incident beams corresponds to the exposure period of the substrate. By rotating and adjusting the first and second reflection units, the angle between the first and second incident beams and the normal to the substrate to be exposed can be changed, thereby changing the angle between the first and second incident beams. This allows the exposure period of the first and second incident beams during interference exposure of the substrate to be exposed to be changed. As a result, the dual-beam exposure optical path system provided by this invention can adjust the exposure period according to the grating period of the diffraction grating fabricated on the substrate to be exposed under the same optical path setup. This enables the dual-beam exposure optical path system to perform exposure work for the fabrication process of diffraction gratings with various different grating periods under the same optical path setup. Attached Figure Description
[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 A schematic diagram of the adjustable-period dual-beam exposure optical path system of this utility model is provided as an example.
[0033] Figure 2 A schematic front view illustrating the connection between the first reflection unit and the first orientation adjustment unit, as an example;
[0034] Figure 3 for Figure 2 Side view;
[0035] Figure 4a This is a schematic diagram showing the angular relationship between the exposure beam and the normal of the substrate to be exposed when the reflective unit is in the first angle state.
[0036] Figure 4bThis is a schematic diagram showing the angular relationship between the exposure beam and the normal of the substrate to be exposed when the reflective unit is in the second angle state.
[0037] Among them, 1-light emission unit, 2-beam splitting unit, 3-first reflection unit, 4-second reflection unit, 5-1-first microscope objective, 5-2-first pinhole, 5-3-first collimating lens, 6-1-second microscope objective, 6-2-second pinhole, 6-3-second collimating lens, 7-third reflection unit, 8-fourth reflection unit, 9-fifth reflection unit, 10-sixth reflection unit, 11-first rotating stage, 12-first pitch stage, 13-first polarization adjustment unit, 14-second polarization adjustment unit. Detailed Implementation
[0038] The technical solution of this utility model will be clearly and completely described below with reference to its embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0039] In this document, the terms "first," "second," and other similar words are not intended to imply any order, quantity, or importance, but are merely used to distinguish different elements. The terms "one," "a," and other similar words are not intended to indicate the existence of only one of the stated things, but rather that the description refers only to one of the stated things, which may have one or more. The terms "comprising," "including," and other similar words are intended to indicate a logical relationship, not a spatial relationship. For example, "A includes B" means that logically B belongs to A, not that spatially B is located inside A. Furthermore, the meanings of the terms "comprising," "including," and other similar words should be considered open-ended, not closed. For example, "A includes B" means that B belongs to A, but B does not necessarily constitute all of A; A may also include other elements such as C, D, and E.
[0040] In this document, the terms "embodiment," "this embodiment," "preferred embodiment," and "one embodiment" do not imply that the description applies only to one specific embodiment, but rather that such description may also be applicable to one or more other embodiments. Those skilled in the art will understand that any description made herein relating to one embodiment can be substituted, combined, or otherwise incorporated with the descriptions in one or more other embodiments. Such substitutions, combinations, or other incorporations resulting in new embodiments are readily conceived by those skilled in the art and fall within the protection scope of this utility model.
[0041] In this description, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0042] The exposure period for interference exposure of the substrate using a dual-beam exposure optical path system satisfies the following formula: D = λ / 2sin(θ). Photoresist is applied to the surface of the substrate to be exposed.
[0043] Where D represents the exposure period, λ represents the incident beam wavelength, and θ represents the angle between the incident beam and the normal to the substrate to be exposed.
[0044] like Figure 1 As shown, this utility model provides an adjustable period dual-beam exposure optical path system, including an optical platform (not shown in the figure) and a light-emitting unit 1, a beam-splitting unit 2, a first beam-expanding and collimating unit, a second beam-expanding and collimating unit, a first reflection unit 3, and a second reflection unit 4 disposed on the optical platform.
[0045] The emitted beam from the light-emitting unit is split into a first beam and a second beam by a beam-splitting unit. The first beam becomes a first parallel beam after passing through a first beam-expanding and collimating unit. The first parallel beam is reflected by a first reflection unit that is rotated and adjusted, and then becomes the first incident beam that enters the substrate to be exposed. The second beam becomes a second parallel beam after passing through a second beam-expanding and collimating unit. The second parallel beam is reflected by a second reflection unit that is rotated and adjusted, and then becomes the second incident beam that enters the substrate to be exposed. The first incident beam and the second incident beam perform interference exposure on the substrate to be exposed.
[0046] The angle between the first incident beam and the second incident beam corresponds to the exposure cycle of the substrate to be exposed.
[0047] By rotating and adjusting the first and second reflection units, the angle between the first and second incident beams and the normal to the substrate to be exposed can be changed, thereby changing the angle between the first and second incident beams. This allows the exposure period of the first and second incident beams during interference exposure of the substrate to be exposed to be changed. As a result, the dual-beam exposure optical path system provided by this invention can adjust the exposure period according to the grating period of the diffraction grating fabricated on the substrate to be exposed under the same optical path setup. This enables the dual-beam exposure optical path system to perform exposure work for the fabrication process of diffraction gratings with various different grating periods under the same optical path setup.
[0048] The first and second reflective units have higher reflectivity, thereby improving light energy utilization. For example, the first reflective unit has a reflectivity greater than 90%, and the second reflective unit has a reflectivity greater than 90%.
[0049] For example, the light-emitting unit may be a laser, the beam-splitting unit may be a PBS beam-splitting prism, the first reflection unit may be a mirror, and the second reflection unit may be a mirror.
[0050] For example, such as Figure 1 As shown, the first beam expanding and collimating unit includes a first beam expanding and filtering unit and a first collimating lens 5-3. For example, the first beam expanding and filtering unit is composed of a first microscope objective 5-1 and a first pinhole 5-2. The first microscope objective is close to the beam splitting unit, the first collimating lens is close to the first reflection unit, and the first pinhole is located at the focusing position of the first microscope objective.
[0051] The emitted beam from the light-emitting unit is split into a first beam by the beam-splitting unit and then focused and expanded by the first microscope objective. The first pinhole filters the first beam at the focusing position of the first microscope objective. The expanded beam of the first beam enters the first collimating lens for collimation to obtain the first parallel beam.
[0052] For example, such as Figure 1 As shown, the second beam expanding and collimating unit includes a second beam expanding and filtering unit and a second collimating lens 6-3. For example, the second beam expanding and filtering unit is composed of a second microscope objective 6-1 and a second pinhole 6-2. The second microscope objective is located near the beam splitting unit, the second collimating lens is located near the second reflection unit, and the second pinhole is located at the focusing position of the second microscope objective.
[0053] The emitted beam from the light-emitting unit is split into a second beam by the beam-splitting unit and then focused and expanded by the second microscope objective. The second pinhole filters the second beam at the focusing position of the second microscope objective. The expanded beam of the second beam enters the second collimating lens for collimation to obtain the second parallel beam.
[0054] For example, the area of the first reflecting unit is not greater than the exit aperture size of the first collimating lens, and the area of the second reflecting unit is not greater than the exit aperture size of the second collimating lens.
[0055] For example, the center of the first reflecting unit and the center of the first collimating lens are located on the same horizontal line, and the center of the second reflecting unit and the center of the second collimating lens are located on the same horizontal line. This ensures that the parallel light beam output by the collimating lens can be transmitted to the substrate to be exposed through the reflecting unit, and ensures that the exposure area of the substrate to be exposed is the set exposure area value, which corresponds to the exit aperture size of the collimating lens.
[0056] As a preferred embodiment, the adjustable-period dual-beam exposure optical path system provided by this utility model may further include a third reflection unit 7, a fourth reflection unit 8, a fifth reflection unit 9, and a sixth reflection unit 10 (e.g., ...) disposed on an optical platform. Figure 1 (As shown).
[0057] The third reflection unit is positioned on the transmission optical path between the light-emitting unit and the beam-splitting unit.
[0058] The fourth and fifth reflection units are disposed on the transmission optical path between the beam splitting unit and the first beam expanding and collimating unit, with the fourth reflection unit being close to the beam splitting unit.
[0059] The sixth reflection unit is located on the transmission optical path between the beam splitting unit and the second beam expanding and collimating unit.
[0060] By setting up a third, fourth, fifth, and sixth reflection unit, the direction of light transmission can be changed by light beam reflection without changing the position of the current component in the exposure system, ensuring that the light beam propagates between the components of the exposure system according to the set light path.
[0061] The third, fourth, fifth, and sixth reflection units here can be exemplified by using reflectors.
[0062] As a preferred embodiment, the adjustable-period dual-beam exposure optical path system of this utility model may further include a first direction adjustment unit and a second direction adjustment unit.
[0063] A first direction adjustment unit is provided at the bottom of the first reflective unit, and a second direction adjustment unit is provided at the bottom of the second reflective unit.
[0064] For example, the first direction adjustment unit mentioned above includes a first rotary table 11 and a first pitch table 12 (e.g., Figures 2-3 As shown in the figure, the second direction adjustment unit includes a second rotary table and a second pitch table.
[0065] The top of the first elevation stage is connected to the first reflecting unit, and the bottom of the first elevation stage is connected to the first rotating stage, which is mounted on the optical platform. The top of the second elevation stage is connected to the second reflecting unit, and the bottom of the second elevation stage is connected to the second rotating stage, which is mounted on the optical platform.
[0066] The first elevation stage allows for adjustment of the elevation angle of the first reflecting unit, ensuring that the center of the first reflecting unit and the center of the first collimating lens are on the same horizontal line. Similarly, the second elevation stage allows for adjustment of the elevation angle of the second reflecting unit, ensuring that the center of the second reflecting unit and the center of the second collimating lens are on the same horizontal line.
[0067] The first rotating stage can be used to adjust the rotation angle of the first reflective unit, and the second rotating stage can be used to adjust the rotation angle of the second reflective unit, so that the angle between the first incident beam and the second incident beam corresponds to the exposure cycle of the substrate to be exposed.
[0068] During the beam splitting operation of the emitted beam from the light-emitting unit through the PBS beam splitter prism, in order to ensure the energy distribution of the first and second split beams is balanced, the adjustable-period dual-beam exposure optical path system of this invention may further include a first polarization adjustment unit. The first polarization adjustment unit is disposed on the optical platform, and the first polarization adjustment unit 13 is disposed on the transmission optical path between the third reflection unit 7 and the beam splitting unit 2 (e.g., ...). Figure 1 As shown), this is used to change the polarization state of the emitted beam, so that the energy distribution of the first and second beams after the emitted beam is split by the PBS beam splitter is balanced. Simultaneously, since the polarization states of the first and second beams are different after the emitted beam from the light-emitting unit is split by the PBS beam splitter, when the beam splitter uses a PBS beam splitter, the polarization states of the first and second beams are different (e.g., the first beam is polarized in state S, and the second beam is polarized in state P). To ensure that the two beams incident on the substrate to be exposed can interfere with each other during exposure, as a preferred embodiment, the adjustable-period dual-beam exposure optical path system of this invention can further include a second polarization adjustment unit. The second polarization adjustment unit is disposed on the optical platform, and the second polarization adjustment unit 14 is disposed on the transmission optical path between the beam splitter unit 2 and the fourth reflection unit 8 (e.g., ...). Figure 1 (as shown), thereby adjusting the first and second beams to have the same polarization state.
[0069] For example, the first polarization adjustment unit and the second polarization adjustment unit described above may be waveplates.
[0070] The following example illustrates the exposure operation of the substrate to be exposed using the adjustable-period dual-beam exposure optical path system of this invention:
[0071] 1. Initially construct a dual-beam exposure optical path system on the optical platform:
[0072] The components of the dual-beam exposure optical path system are assembled on the optical platform according to their set positions and connections, thus completing the initial construction of the optical path.
[0073] The constituent units include a light-emitting unit, a beam-splitting unit, a first polarization adjustment unit, a second polarization adjustment unit, a first microscope objective, a first pinhole, a first collimating lens, a second microscope objective, a second pinhole, a second collimating lens, a first rotating stage, a first elevation stage, a second rotating stage, a second elevation stage, a first reflection unit, a second reflection unit, a third reflection unit, a fourth reflection unit, a fifth reflection unit, and a sixth reflection unit.
[0074] 2. Rotate the first elevation stage so that the center of the first reflecting unit and the center of the first collimating lens are on the same horizontal line. Rotate the second elevation stage so that the center of the second reflecting unit and the center of the second collimating lens are on the same horizontal line.
[0075] 3. Calculate the angle between the two exposure beams (first incident beam / second incident beam) and the normal of the substrate to be exposed based on the required grating period of the diffraction grating fabricated on the substrate to be exposed, thereby determining the angle between the two exposure beams (first incident beam and second incident beam).
[0076] For example, based on the required grating period of the diffraction grating fabricated on the substrate to be exposed, the angle θ between the two exposure beams (first incident beam / second incident beam) and the normal of the substrate to be exposed is calculated as θ = arcsin(2D / λ), resulting in an angle of 2θ between the two exposure beams (first incident beam and second incident beam).
[0077] 4. Rotate the rotary table below the first reflective unit and the rotary table below the second reflective unit so that the rotation angle of the first reflective unit and the second reflective unit satisfies the angle between the two exposure beams (first incident beam / second incident beam) corresponding to the grating period required for the diffraction grating to be prepared on the substrate to be exposed and the normal of the substrate to be exposed.
[0078] For example, such as Figure 4a As shown in the diagram, this figure only illustrates a single beam. The angle between the optical axis of the collimating lens and the Z-axis is β. When the reflecting unit does not rotate and the reflecting surface is parallel to the X-axis, the incident angle of the parallel beam on the reflecting surface is β, and the angle between the reflected light of the parallel beam and the normal of the substrate to be exposed is also β. At this time, the exposure period of the optical path is: D = λ / 2sin(β).
[0079] When the required exposure period of the optical path becomes smaller or larger, it is necessary to rotate the reflection unit to adjust the angle at which the two exposure beams (first incident beam / second incident beam) are incident on the substrate to be exposed. Figure 4bTaking the reduction of the optical path exposure period as an example, the reflective unit is rotated clockwise by α degrees. At this time, the incident angle of the parallel light beam on the reflective unit becomes β+α, and the reflection angle is also β+α. Then, the angle between the exposure beam that finally hits the substrate and the normal direction of the substrate to be exposed is θ = β+2α. When the required exposure period is known, the angle θ can be calculated, and then the angle α that the reflective unit needs to rotate is calculated to obtain α = (θ-β) / 2.
[0080] 5. Use the established dual-beam exposure optical path system to perform the exposure operation on the substrate to be exposed, and the exposure period is consistent with the grating period of the diffraction grating required for the substrate to be exposed.
[0081] The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art can still make modifications or equivalent substitutions to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model are within the protection scope of the claims of this utility model pending approval.
Claims
1. A dual-beam exposure optical path system with adjustable period, characterized in that, It includes a light-emitting unit, a beam-splitting unit, a first beam-expanding and collimating unit, a second beam-expanding and collimating unit, a first reflection unit, and a second reflection unit; The emitted beam from the light-emitting unit is split into a first beam and a second beam by the beam-splitting unit. The first beam becomes a first parallel beam after passing through a first beam-expanding and collimating unit. The first parallel beam is reflected by a first reflection unit that is rotated and adjusted, and then becomes the first incident beam that enters the substrate to be exposed. The second beam becomes a second parallel beam after passing through a second beam-expanding and collimating unit. The second parallel beam is reflected by a second reflection unit that is rotated and adjusted, and then becomes the second incident beam that enters the substrate to be exposed. The first incident beam and the second incident beam are used to perform interference exposure on the substrate to be exposed. The angle between the first incident beam and the second incident beam corresponds to the exposure cycle of the substrate to be exposed.
2. The adjustable-period double-beam exposure light path system according to claim 1, wherein, It also includes a first direction adjustment unit and a second direction adjustment unit; The first direction adjustment unit is disposed at the bottom of the first reflective unit, and the second direction adjustment unit is disposed at the bottom of the second reflective unit.
3. The adjustable period two-beam exposure optical path system according to claim 2, wherein, The first orientation adjustment unit includes a first rotary table and a first pitch table, and the second orientation adjustment unit includes a second rotary table and a second pitch table; The top of the first pitch stage is connected to the first reflective unit, and the bottom of the first pitch stage is connected to the first rotary stage. The top of the second pitch stage is connected to the second reflector unit, and the bottom of the second pitch stage is connected to the second rotary stage.
4. The adjustable period two-beam exposure optical path system of claim 1, wherein, The reflectivity of the first reflective unit is greater than 90%, and the reflectivity of the second reflective unit is greater than 90%.
5. The adjustable period two-beam exposure optical path system of claim 1, wherein, The first beam expanding and collimating unit includes a first microscope objective, a first pinhole, and a first collimating lens; the first microscope objective is close to the beam splitting unit, the first collimating lens is close to the first reflecting unit, and the first pinhole is located at the focusing position of the first microscope objective. The second beam expanding and collimating unit includes a second microscope objective, a second pinhole, and a second collimating lens; the second microscope objective is close to the beam splitting unit, the second collimating lens is close to the second reflection unit, and the second pinhole is located at the focusing position of the second microscope objective.
6. The adjustable period, dual-beam exposure light path system of claim 5, wherein, The area of the first reflecting unit is not greater than the exit aperture size of the first collimating lens, and the area of the second reflecting unit is not greater than the exit aperture size of the second collimating lens.
7. The adjustable-period dual-beam exposure optical path system according to claim 5, characterized in that, The center of the first reflecting unit and the center of the first collimating lens are located on the same horizontal line, and the center of the second reflecting unit and the center of the second collimating lens are located on the same horizontal line.
8. The adjustable period, dual-beam exposure light path system of claim 1, wherein, It also includes a third reflection unit, a fourth reflection unit, a fifth reflection unit, and a sixth reflection unit; The third reflection unit is disposed on the transmission optical path between the light-emitting unit and the beam-splitting unit; The fourth and fifth reflection units are disposed on the transmission optical path between the beam splitting unit and the first beam expanding and collimating unit, with the fourth reflection unit being close to the beam splitting unit. The sixth reflection unit is disposed on the transmission optical path between the beam splitting unit and the second beam expanding and collimating unit.
9. The adjustable period, dual-beam exposure light path system of claim 8, wherein, The beam splitting unit uses a PBS beam splitter prism.
10. The adjustable period double-beam exposure optical path system according to claim 9, wherein, It also includes a first polarization adjustment unit and a second polarization adjustment unit; The first polarization adjustment unit is arranged on a transmission light path between the third reflecting unit and the beam splitting unit, and the second polarization adjustment unit is arranged on a transmission light path between the beam splitting unit and the fourth reflecting unit.