A reflective dual-beam interference exposure system and a method for adjusting the system to consider both ruling density and aberration

Abstract

A kind of reflective double-beam interference exposure system considers the adjustment method of line density and aberration, comprising: constructing line density standard module, generates standard reference beam for adjusting the line density of exposure system; Build reflective double-beam interference exposure system, respectively with the point of the focus of the standard reference beam of ±1 level after off-axis parabolic mirror, as the nominal focal point of each off-axis mirror in double-beam light path, by constantly adjusting the spatial position of off-axis parabolic mirror and combining the wavefront measurement of spherical interferometer, make the nominal focal point of off-axis mirror and real focal point spatial position coincide, complete the construction of double-beam interference exposure system.The present application solves the problem that the reflective double-beam interference exposure system is difficult to control the aberration and line density accurately during the adjustment process, and provides a new idea for the high-precision adjustment of meter-level large-aperture reflective interference exposure system.

Description

Technical Field

[0001] This invention relates to the field of large-aperture diffraction grating fabrication, specifically a reflective double-beam interference exposure system and its assembly method that balances grating density and aberrations. Background Technology

[0002] Meter-scale large-aperture diffraction gratings are core components of systems such as ultra-intense and ultra-short laser devices, high-energy spectral beam combining laser weapons, and high-precision displacement measurement gratings. Their fabrication process is highly complex, primarily involving photoresist coating on the grating substrate, photolithography, development, ion beam etching, and coating replication. Among these, photolithography is the key process for fabricating high-quality diffraction gratings, as the grating's line density and wavefront aberrations largely depend on this step. Currently, meter-scale large-aperture dual-beam interference exposure systems are mainly used for photolithography. In this technique, the ultraviolet laser beam emitted by the laser is split into two beams of equal intensity by a beam splitter. After beam expansion and collimation by the exposure system, interference occurs within the photoresist on the grating substrate surface, forming a latent image of the photoresist grating. Subsequently, wet development and etching processes are used to fabricate the diffraction grating element. Compared to traditional large-aperture transmission-type two-beam interferometry (DBI) exposure systems, reflection-type DBI exposure systems based on off-axis parabolic mirrors are less limited by the aperture of the collimating mirror material, making it easier to fabricate large-aperture diffraction gratings on the meter scale and above. However, reflection-type DBI exposure systems are characterized by a smaller field of view and non-coaxial collimation paths. This results in greater aberrations under the same optical processing and assembly conditions, and the non-coaxial nature of the collimation system makes precise control of the grating fringe density more difficult. This is mainly because the fringe density of the DBI exposure system (the reciprocal of the grating period Λ, i.e., 1 / Λ) depends on the interference angle between the two beams. From the interference fringe period formula Λ=λ / 2 / sin(θ), it can be seen that, given a fixed wavelength λ of the light source, controlling the fringe density of the exposure system is essentially adjusting the interference angle θ between the two beams. However, adjusting the angle between the two beams means that the focal point of the off-axis parabolic collimator in the exposure system also changes. This leads to the coupling effect between the wavefront aberration and the scribe line density during the assembly and adjustment of the reflective two-beam interferometry exposure system, making it extremely difficult to simultaneously consider both the interference system aberrations and the scribe line density. Continuous iterative adjustments are required. To address the aberration control problem in reflective two-beam interferometry exposure systems, patent CN202311186275, entitled "A Method for Aberration Control in a Reflective Two-Beam Interferometry Exposure System," proposes a method for adjusting the wavefronts of the two interfering beams using a deformable mirror. This method can effectively control the wavefront aberration of the interference field, but it cannot simultaneously adjust the scribe line density during the assembly and adjustment process.

[0003] Therefore, researching and solving the precision assembly and adjustment problem of large-aperture reflective two-beam interferometry exposure systems that simultaneously consider line density and aberrations is of great significance for promoting the application of reflective interferometry exposure technology in the manufacturing of large-aperture diffraction gratings at the meter level and above. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that existing reflective two-beam interferometric exposure systems are difficult to control precisely at the same time during the assembly and adjustment process. It provides an assembly and adjustment method for reflective two-beam interferometric exposure systems that takes into account both the surface density and aberrations. By constructing a surface density standard module and combining interferometer wavefront detection and spatial filtering adjustment, high-precision assembly of the reflective two-beam interferometric system can be achieved.

[0005] The technical solution of the present invention is as follows:

[0006] A method for assembling and adjusting a reflective two-beam interferometric exposure system that balances line density and aberrations, characterized by including:

[0007] A standard grid density module is constructed to generate a standard reference beam for adjusting the grid density of the exposure system and system setup. The standard grid density module includes: a laser autocollimator, a standard reference grating, a large-aperture standard plane mirror, a semi-transparent mirror, a CCD camera, and a computer. The laser autocollimator is used to emit a parallel laser beam. The standard reference grating has a period... Where, λ r λ is the output wavelength of the laser autocollimator. e The output wavelength of the ultraviolet exposure light source is d, and the period of the target grating is d; a large-aperture standard plane mirror is used to reflect diffracted light and achieve optical path self-collimation; a semi-transparent mirror and a CCD camera are used to monitor interference fringes and calibrate the perpendicularity of the optical path;

[0008] The ±1st order reflected / transmitted diffracted light is generated using the scribed density standard module as a reference beam. By adjusting the pitch and yaw angles of the large-aperture standard plane mirror, the transmitted diffracted light and the reflected diffracted light are superimposed and interfered on the CCD camera until the interference fringes disappear, thus completing the vertical calibration of the large-aperture standard plane mirror.

[0009] A reflective two-beam interferometric exposure system was constructed. By adjusting the spatial position of the off-axis parabolic mirror and combining it with wavefront measurement using a spherical interferometer, the wavefront aberration of the large-aperture beam reflected by the large-aperture standard plane was minimized. The true focal positions of each off-axis mirror in the two-beam optical path were determined, and the construction of a two-beam interferometric exposure system with precise scribe line density was completed.

[0010] A standard reference beam is generated using a scribe line density standard module. The angle between the interference beams is controlled, thereby controlling the interference scribe line density. Using the nominal focal point of the standard reference beam generated by the scribe line density standard module after focusing by an off-axis mirror as a reference, a spherical interferometer is installed, and the wavefront of the beam emitted from the large-aperture off-axis mirror is measured to determine the true focal point position of the off-axis parabolic mirror. Through the above operations, the assembly and adjustment of a reflective dual-beam interferometric exposure system with simultaneously controllable scribe line density and aberrations are completed. Specifically:

[0011] Step 1) Construction of the scribing density standard module

[0012] Step 1.1) Based on the output wavelength λ of the laser autocollimator r λ output wavelength of ultraviolet exposure light source e And the period d of the grating to be fabricated, and the design of the fabrication period. The standard reference grating;

[0013] Step 1.2) Install the laser autocollimator and the standard reference grating, and adjust their spatial orientation so that the parallel laser beam emitted by the laser autocollimator is perpendicularly incident on the surface of the standard grating. After beam splitting, it forms two ±1st order reflected diffracted beams and two ±1st order transmitted diffracted beams. The angle θ between the reflected diffracted beam and the normal to the grating surface satisfies the following formula:

[0014]

[0015] Step 2) Adjusting the optical path of the reflective dual-beam interferometry exposure system

[0016] Step 2.1) Install the large-aperture standard plane mirror and the semi-transparent mirror in sequence, and connect the CCD camera to the control computer. Adjust the tilt and pitch angles of the large-aperture standard plane mirror so that the +1st order transmitted diffracted light reflected by it returns along the original path, passes through the standard reference grating in the etched density standard module, and then interferes with the +1st order reflected diffracted light on the CCD camera.

[0017] Step 2.2) Continuously fine-tune the pitch and yaw of the large-aperture standard plane mirror until the interference fringes on the CCD camera disappear, indicating that the +1st order transmitted diffracted light is strictly perpendicular to the large-aperture standard plane mirror. At this point, fix the position of the standard plane mirror. This completes the construction of the scribe line density standard module that can be used for the lower optical path adjustment and the generation of the standard reference beam.

[0018] Step 2.3) Initially install the large-aperture off-axis parabolic mirror in the lower optical path;

[0019] Step 2.4) Install and adjust the position of the space filter so that the focal point of the convergent beam formed by the +1st order reflected diffracted reference light emitted from the scribed density standard module passes through the pinhole on the space filter after passing through the large-aperture off-axis parabolic mirror.

[0020] Step 2.5) Install and adjust the position of the spherical interferometer so that the focal point of its outgoing beam also passes through the pinhole on the spatial filter. Use the spherical interferometer to test and record the wavefront aberration of the large-aperture beam reflected back by the large-aperture standard plane mirror.

[0021] Step 2.6) Repeat the adjustment of the spatial position of the large-aperture off-axis parabolic mirror in the lower optical path, and repeat the operation process of Step 2.4)-Step 2.5) until the wavefront aberration of the large-aperture beam measured by the spherical interferometer is minimized. Then, fix the position of the large-aperture off-axis parabolic mirror and the spatial filter in the lower optical path.

[0022] Step 2.7) Remove the spherical interferometer, turn on the ultraviolet laser source, and place a half-wave plate and a polarizing beam splitter along the ultraviolet laser beam transmission direction. The ultraviolet laser beam is split into two beams, namely a reflected beam and a transmitted beam, after passing through the polarizing beam splitter. Place a reflecting mirror and a focusing objective in sequence along the transmission direction of the reflected beam, and repeatedly adjust the positions of the reflecting mirror and the focusing objective so that the focal point of the ultraviolet laser beam after being focused by the focusing objective passes through the pinhole on the spatial filter. This completes the assembly and adjustment of the lower optical path.

[0023] Step 3) Optical path assembly and adjustment of the reflective dual-beam interferometry exposure system

[0024] Step 3.1) Rotate the large-aperture standard plane mirror counterclockwise, and adjust the large-aperture standard plane mirror to be perpendicular to the -1st order transmitted diffracted light according to the operation method of Step 2.1)-Step 2.2), so as to complete the construction of the scribed density standard module for upper optical path assembly and adjustment and the generation of the standard reference beam.

[0025] Step 3.2) Initially install the large-aperture off-axis parabolic mirror in the optical path;

[0026] Step 3.3) Install and adjust the position of the space filter so that the focal point of the convergent beam formed by the -1st order reflected diffracted reference light emitted from the scribed density standard module after passing through the large-aperture off-axis parabolic mirror passes through the pinhole on the space filter.

[0027] Step 3.4) Install and adjust the position of the spherical interferometer so that the focal point of its outgoing beam also passes through the pinhole on the spatial filter. Use the spherical interferometer to test and record the wavefront aberration of the large-aperture beam reflected back by the large-aperture standard plane mirror 8.

[0028] Step 3.5) Repeat the adjustment of the spatial position of the large-aperture off-axis parabolic mirror in the upper optical path, and repeat the operation process of steps 2.3)-2.4) until the wavefront aberration of the large-aperture beam measured by the spherical interferometer is minimized. Then, fix the position of the large-aperture off-axis parabolic mirror and the spatial filter in the upper optical path.

[0029] Step 3.6) Remove the spherical interferometer, turn on the ultraviolet laser source, and place the half-wave plate, reflector, and focusing objective in sequence along the direction of the transmitted beam. Repeatedly adjust the positions of the reflector and focusing objective so that the focus of the ultraviolet laser beam after being focused by the focusing objective passes through the pinhole on the spatial filter. This completes the assembly and adjustment of the upper optical path.

[0030] Compared with the prior art, the present invention has the following beneficial technical effects:

[0031] 1. A standard module for the scribe line density, constructed using a standard reference grating, a laser autocollimator, a semi-transparent mirror, and a CCD camera, provides a benchmark for the assembly and adjustment of a reflective dual-beam interferometric exposure system. The assembly and adjustment process simultaneously considers the assembly and adjustment accuracy of the scribe line density and wavefront aberration of the exposure system, thus solving the problem of crosstalk between the scribe line density adjustment and wavefront aberration adjustment of the exposure system in traditional assembly and adjustment methods.

[0032] 2. The reference beam in the scribe line density standard module greatly facilitates the search for the focal position of the large-aperture off-axis parabolic mirror, significantly improving the assembly and adjustment efficiency of the two-beam interferometric exposure system. Moreover, the scribe line density standard module uses a standard reference grating, ensuring the repeatability accuracy of the scribe line density assembly and adjustment of the two-beam interferometric exposure system, laying the foundation for the fabrication of diffraction gratings with high scribe line density consistency requirements.

[0033] 3. This assembly and adjustment method is applicable to any technical solution that uses two-beam interference exposure technology to prepare diffraction gratings, and has strong versatility. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the lower optical path of the mounting and adjustment method that takes into account both the scribing density and aberration in an embodiment of the reflective dual-beam interferometric exposure system of the present invention.

[0035] Figure 2 This is a schematic diagram of the upper optical path of the mounting and adjustment method that takes into account both the scribing density and aberration in an embodiment of the reflective dual-beam interferometric exposure system of the present invention.

[0036] In the diagram: 1-Laser autocollimator, 2-Parallel laser beam, 3-Standard reference grating, 4-+1st order reflected diffracted light, 5-1st order reflected diffracted light, 6-+1st order transmitted diffracted light, 7-1st order transmitted diffracted light, 8-Large aperture standard plane mirror, 9-Semi-transparent mirror, 10-CCD camera, 11-Computer, 12-Lower optical path off-axis parabolic mirror, 13-Upper optical path off-axis parabolic mirror, 14-First focusing beam, 15-Second focusing beam, 16-First pinhole, 17-Second pinhole, 18-First focusing objective, 19-Second focusing objective, 20-Spherical interferometer, 21-First reflecting mirror, 22-Second reflecting mirror, 23-Third reflecting mirror, 24-First half-wave plate, 25-Polarizing beam splitter, 26-Second half-wave plate, 27-Ultraviolet laser source, 28-First large aperture beam, 29-Second large aperture beam Detailed Implementation

[0037] The present invention will be further described below with reference to embodiments and accompanying drawings, but this should not be construed as limiting the scope of protection of the present invention.

[0038] The aberration control device employing a reflective dual-beam interferometry exposure system includes:

[0039] A spherical interferometer is used to measure and record the wavefront aberration of the beam emitted from a reflective interferometric exposure system. It achieves dynamic testing and feedback of aberrations through a self-collimating optical path (combined with a standard plane mirror).

[0040] A spatial filter is used to locate the ideal point source generated by the spherical interferometer and to spatially filter it, ensuring that the standard reference beam and the ultraviolet beam share the same path.

[0041] Deformable mirrors are used to dynamically control the wavefront of one beam in a dual-beam interferometric exposure system, compensate for aberrations, and match the wavefront aberration of the other beam, thereby reducing the wavefront aberration of the grating diffraction formed after interference and improving the grating quality.

[0042] A standard plane mirror is used to reflect the laser beam emitted from the interferometric exposure system, allowing it to return along its original path. This mirror, together with the spherical interferometer, forms the wavefront aberration autocollimation measurement optical path, ensuring the perpendicularity of the optical path and providing a reference for aberration testing.

[0043] A method for assembling and adjusting a reflective two-beam interferometric exposure system that balances line density and aberrations, specifically including:

[0044] S1. Construction of the standard module for rubbing density:

[0045] This scribe line density standard module generates a standard reference beam for adjusting the scribe line density and system setup of the exposure system. It mainly includes the following components:

[0046] Laser autocollimator 1 emits a parallel beam perpendicularly incident on a standard reference grating, generating ±1st order diffracted light. In this embodiment, a NORMAT-3210 (Shanghai Nuoxu Electromechanical Technology Co., Ltd.) with an output wavelength of 630nm is used.

[0047] Standard reference grating 3, size 50mm × 50mm, grating period d 标 It is 2307.67nm.

[0048] A large-aperture standard plane mirror 8 reflects the transmitted light beam and forms interference with the reflected light. The fringe state is monitored by a CCD. In this embodiment, the size is 1650mm×1120mm, and the reflected wavefront is better than λ / 8@632.8nm.

[0049] The semi-transparent and semi-reflective mirror 9 splits the beam to the CCD and the spherical interferometer, enabling simultaneous interference calibration and wavefront measurement.

[0050] The CCD camera 10, using the Hikvision robot MV-CA013-20GM model, is used to capture moiré fringe offset.

[0051] Step 1) Adjusting the optical path of the reflective dual-beam interferometry exposure system

[0052] Step 1.1) Prepare the standard reference grating 3. In this embodiment, the grating density of the dual-beam interference exposure system is 1400 lines / mm (grating period 714.28nm), and the output wavelength λe of the ultraviolet exposure light source 27 is 390nm. Therefore, the period of the standard reference grating 3 is 2307.67nm.

[0053] Step 1.2) Install the laser autocollimator 1 and the standard reference grating 3, and adjust their spatial orientation so that the parallel laser beam emitted by the laser autocollimator 1 is perpendicularly incident on the surface of the standard grating 3. After beam splitting, it forms two ±1st order reflected diffracted beams 4 and 5 and two ±1st order transmitted diffracted beams 6 and 7. The angle θ between the reflected diffracted beams 4 and 5 and the normal to the grating surface is 15.84°.

[0054] Step 1.3) Install the large-aperture standard plane mirror 8 and the semi-transparent mirror 9 in sequence, and connect the CCD camera 10 to the computer 11. Adjust the tilt and pitch angles of the large-aperture standard plane mirror 8 so that the -1st order transmitted diffracted light 7 reflected by it returns along the original path, passes through the standard reference grating 3, and then interferes with the +1st order reflected diffracted light 4 on the CCD camera 10.

[0055] Step 1.4) Continuously fine-tune the pitch and yaw of the large-aperture standard plane mirror 8 until the interference fringes on the CCD camera 10 disappear, indicating that the -1st order transmitted diffracted light 7 is strictly perpendicular to the large-aperture standard plane mirror. At this time, fix the position of the standard plane mirror 8. This completes the construction of the scribe line density standard module that can be used for the lower optical path adjustment and the generation of the standard reference beam 4.

[0056] Step 1.5) Install the large-aperture off-axis parabolic mirror 12 in the lower optical path;

[0057] Step 1.6) Install and adjust the position of the first pinhole 16 so that the focal point of the first focused beam 14 formed by the standard reference beam 4 emitted from the scribing density standard module after passing through the large-aperture off-axis parabolic reflector passes through the first pinhole 16.

[0058] Step 1.7) Install and adjust the position of the spherical interferometer 20 so that the focal point of its outgoing beam also passes through the first pinhole 16. Use the spherical interferometer 20 to test and record the wavefront aberration of the first large-aperture beam 28 reflected back by the large-aperture standard plane mirror.

[0059] Step 1.8) Repeat the adjustment of the spatial position of the large-aperture off-axis parabolic mirror 12 in the lower optical path, and repeat the operation process of steps 1.6)-1.7) until the wavefront aberration of the first large-aperture beam 28 measured by the spherical interferometer 20 is minimized. Then, fix the position of the large-aperture off-axis parabolic mirror 12 and the first pinhole 16 in the lower optical path.

[0060] Step 1.9) Remove the spherical interferometer 20, turn on the ultraviolet laser source 27, and place the second half-wave plate 26 and the polarizing beam splitter 25 along the ultraviolet laser beam transmission direction. The ultraviolet laser beam is split into two beams, namely the reflected beam and the transmitted beam, after passing through the polarizing beam splitter 25. Place the first reflecting mirror 21 and the first focusing objective 18 in sequence along the transmission direction of the reflected beam. Repeatedly adjust the positions of the first reflecting mirror 21 and the first focusing objective 18 so that the focal point of the ultraviolet laser beam after being focused by the first focusing objective 18 passes through the first pinhole 16. This completes the assembly and adjustment of the lower optical path.

[0061] Step 2) Optical path assembly and adjustment of the reflective dual-beam interferometry exposure system

[0062] Step 2.1) Rotate the large-aperture standard plane mirror 8 counterclockwise, and adjust the large-aperture standard plane mirror 8 to be perpendicular to the +1st order transmitted diffracted light 6 according to the operation method of Step 1.2)-Step 1.4) to complete the construction of the scribed density standard module for upper optical path assembly and adjustment and the generation of standard reference beam 5.

[0063] Step 2.2) Initially install the large-aperture off-axis parabolic mirror 13 on the optical path;

[0064] Step 2.3) Install and adjust the position of the second pinhole 17 so that the focal point of the second focused beam 15 formed after the standard reference beam 5 passes through the large-aperture off-axis parabolic mirror 13 passes through the second pinhole 17.

[0065] Step 2.4) Install and adjust the position of the spherical interferometer 20 so that the focal point of its outgoing beam also passes through the second pinhole 17. Use the spherical interferometer 20 to test and record the wavefront aberration of the second large-aperture beam 29 reflected back by the large-aperture standard plane mirror 8.

[0066] Step 2.5) Repeat the adjustment of the spatial position of the large-aperture off-axis parabolic mirror 13 in the upper optical path, and repeat the operation process of steps 1.3)-1.4) until the wavefront aberration of the second large-aperture beam 29 measured by the spherical interferometer 20 is minimized. Then, fix the position of the large-aperture off-axis parabolic mirror 13 and the second pinhole 17 in the upper optical path.

[0067] Step 2.6) Remove the spherical interferometer 20, turn on the ultraviolet laser source 27, and place the third reflecting mirror 23, the first half-wave plate 24, the second reflecting mirror 22, and the second focusing objective 19 in sequence along the direction of the transmitted beam. Repeatedly adjust the positions of the second reflecting mirror 22 and the second focusing objective 19 so that the focal point of the ultraviolet laser beam after being focused by the second focusing objective 19 passes through the second pinhole 17. This completes the assembly and adjustment of the upper optical path.

[0068] This technology, through the synergy of aberration control devices and assembly methods, ensures that the system grating periodic error is <0.1%, achieving micron-level precision, and reducing assembly time to one-third of traditional methods. The RMS value of the wavefront aberration of the diffracted grating after interference is shown.

Claims

1. A method for assembling and adjusting a reflective two-beam interferometric exposure system that balances line density and aberrations, characterized in that, include: Construct a scribing density standard module, the scribing density standard module comprising: A laser autocollimator is used to emit a parallel laser beam; The standard reference grating has a period of , where λ r λ is the output wavelength of the laser autocollimator. e d is the output wavelength of the ultraviolet exposure light source, and d is the period of the target grating. Large-aperture standard plane mirrors are used to reflect diffracted light and achieve optical path self-collimation; A semi-transparent mirror and a CCD camera are used to monitor interference fringes and calibrate the perpendicularity of the optical path; The module for constructing the scale density standard specifically includes: Install a laser autocollimator and a standard reference grating, and adjust their relative positions so that the parallel laser beam emitted by the laser autocollimator is perpendicularly incident on the surface of the standard reference grating. After beam splitting, it forms two ±1st order reflected diffracted beams and two ±1st order transmitted diffracted beams. The diffraction angle θ of the standard reference beam, that is, the angle θ between the reflected diffracted beam and the normal to the surface of the standard grating, satisfies the following formula: ； The ±1st order reflected diffracted light and ±1st order transmitted diffracted light are generated using the scribed line density standard module as reference beams. By adjusting the pitch and yaw angles of the large-aperture standard plane mirror, the transmitted diffracted light and the reflected diffracted light are superimposed and interfered on the CCD camera until the interference fringes disappear, thus completing the vertical calibration of the large-aperture standard plane mirror. A reflective dual-beam interferometric exposure system was constructed. By adjusting the spatial position of the off-axis parabolic mirror and combining it with wavefront measurement using a spherical interferometer, the wavefront aberration of the large-aperture beam reflected by the large-aperture standard plane was minimized. The true focal positions of each off-axis mirror in the dual-beam optical path were determined, and the construction of a dual-beam interferometric exposure system with precise scribe line density was completed. The installation position of the semi-transparent mirror satisfies the following conditions: the interference beam captured by the CCD camera is split into beams and sent to the computer, while allowing part of the beam to be reflected back to the large-aperture plane mirror to form a self-collimating loop.

2. The assembly and adjustment method for a reflective two-beam interferometric exposure system that balances line density and aberrations according to claim 1, characterized in that, The lower optical path assembly and adjustment steps of the reflective dual-beam interferometry exposure system are as follows: S2.1 Install and adjust the large-aperture standard plane mirror so that the -1st order transmitted diffracted light returns along the original path. Install a semi-transparent mirror so that the -1st order transmitted diffracted light returning along the original path passes through the standard reference grating and together with the +1st order reflected diffracted light, it is reflected by the semi-transparent mirror and forms interference on the CCD camera. S2.2 Finely adjust the large-aperture standard plane mirror until the interference fringes disappear, fix its position, and complete the generation of the standard reference beam for the lower optical path; S2.3 Install the off-axis parabolic reflector of the lower optical path and adjust its position so that the focal point of the lower optical path focused beam formed by the reflection of the lower optical path standard reference beam passes through the first pinhole. S2.4 Install a spherical interferometer so that the focal point of its outgoing beam passes through the first pinhole, and measure the wavefront aberration of the first large-aperture beam; S2.5 Iteratively adjust the position of the off-axis parabolic mirror until the wavefront aberration is minimized, then fix its position.

3. The assembly and adjustment method for a reflective two-beam interferometry exposure system that balances line density and aberrations according to claim 1, characterized in that, The optical path assembly and adjustment steps for the reflective dual-beam interferometry exposure system are as follows: S3.1 Adjust the large-aperture standard plane mirror so that it is perpendicular to the +1st order transmitted diffracted light to complete the generation of the standard reference beam in the upper optical path; S3.2 Install the off-axis parabolic reflector of the upper optical path and adjust its position so that the focal point of the upper optical path focused beam formed by the reflection of the upper optical path standard reference beam passes through the second pinhole. S3.3 Install a spherical interferometer so that the focal point of its outgoing beam passes through the second pinhole to measure the wavefront aberration of the second largest aperture beam; S3.4 Iteratively adjust the position of the off-axis parabolic mirror until the wavefront aberration is minimized, then fix its position.

4. The assembly and adjustment method of a reflective two-beam interferometric exposure system that balances line density and aberrations according to claim 1, characterized in that, The ultraviolet optical path assembly and adjustment steps of the reflective dual-beam interferometry exposure system are as follows: S4.1 Turns on the ultraviolet laser source, which splits the beam into a reflected beam and a transmitted beam by a polarizing beam splitter prism; S4.2 Adjust the first reflecting mirror and the first focusing objective lens of the lower optical path so that the focal point of the reflected beam passes through the first pinhole; S4.3 Adjust the second reflecting mirror and the second focusing objective in the upper optical path so that the focal point of the transmitted beam passes through the second pinhole.

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