Interference Exposure Device

Abstract

This invention relates to the field of interferometric exposure technology. It proposes an interferometric exposure device comprising a beam generating unit, a beam splitting unit, a working plane, and reflection units corresponding to the first and second beams. The reflection unit includes a reflector and an adjustment unit. By adjusting the position of the reflector, the incident angle of the two beams on the working plane can be precisely controlled, thereby adjusting the interference angle and fringe period, enabling rapid switching between micro / nano structures with different periods. The reflective optical path helps maintain wavefront continuity and interference stability. Combined with precise adjustment, it improves alignment accuracy, repeatability, and exposure reproducibility. It also facilitates integration with modules such as light intensity matching and polarization control, enhancing process versatility and fabrication flexibility.

Description

Technical Field

[0001] This utility model relates to the field of interference exposure technology, and in particular to an interference exposure device. Background Technology

[0002] Interference exposure is a key technology for fabricating micro- and nano-periodic structures by superimposing two or more coherent beams of light onto a working plane (such as a photoresist surface) to form periodic bright and dark stripes.

[0003] Existing technologies employ fixed optical geometry (such as fixed supports or optical stages) to ensure stability, but this results in the interference angle being non-adjustable or having a limited adjustment range, making it difficult for the same platform to meet the fabrication requirements of various periodic structures. Limited angle adjustability also affects the versatility and flexibility of the process, increasing the workload of changing optical platforms or realigning for different periodic requirements. Utility Model Content

[0004] In view of the shortcomings of the prior art described above, the purpose of this utility model is to propose an interference exposure device to improve the flexibility of interference exposure.

[0005] To achieve the above and other related objectives, this utility model proposes an interference exposure device, comprising:

[0006] Beam generating unit, used to emit a beam;

[0007] A beam splitting unit is disposed in the path of the beam to split the beam into a first beam and a second beam;

[0008] The working surface is used to place the material to be etched.

[0009] A set of reflection units is provided for the first beam and the second beam respectively. The reflection units are used to reflect the first beam and the second beam to the working plane to form an interference pattern.

[0010] The reflection unit includes a reflector and an adjustment unit. The adjustment unit is used to adjust the position of the reflector to adjust the incident angle of the first beam and the second beam on the working plane.

[0011] In an optional embodiment of the present invention, a linear drive mechanism is further included, which is used to drive the working plane to move along a first direction, the first direction being the bisector of the angle between the first beam and the second beam.

[0012] In an optional embodiment of this utility model, the reflector includes a first reflector and a second reflector, wherein the first reflector is used to receive the light beam emitted from the beam splitter, and the second reflector is used to receive the light beam reflected by the first reflector.

[0013] In an optional embodiment of this utility model, the adjustment unit is configured to drive the first reflector and the second reflector to rotate around a second direction, and the adjustment unit is configured to drive the second reflector to translate along a third direction, the second direction being perpendicular to the directions of the first beam and the second beam, and the third direction being perpendicular to the second direction.

[0014] In one optional embodiment of this utility model, the set of reflecting units corresponding to the first beam and the set of reflecting units corresponding to the second beam are arranged in a mirror-symmetric manner.

[0015] In an optional embodiment of this utility model, the beam generating unit includes a beam generator, a third reflecting mirror, a fourth reflecting mirror, a beam expander, and a λ / 2 waveplate arranged sequentially along the beam direction.

[0016] In an optional embodiment of this invention, the incident angle of the light beam entering the third and fourth reflecting mirrors is 45°.

[0017] In one optional embodiment of this invention, the wavelength of the light beam emitted by the beam generator is 400-500 nanometers.

[0018] In an optional embodiment of this utility model, a λ / 4 waveplate is disposed between the beam splitting unit and the reflecting unit.

[0019] In one optional embodiment of this utility model, the beam-splitting unit is a polarizing beam-splitting prism.

[0020] The technical advantages of this invention are as follows: by setting an adjustable reflector and adjustment unit in the reflection unit, the incident angles of the first beam and the second beam can be precisely controlled, thereby making the interference angle adjustable and directly adjusting the interference fringe period. This enables rapid switching of micro-nano structures with different periods on the same device, significantly improving the versatility of the process and the flexibility of fabrication. The reflective optical path reduces the influence of chromatic aberration on the wavefront, making it easier to maintain wavefront continuity and interference stability, and reducing the need for complex optical path compensation. The precision adjustment unit enables high-precision alignment and repeatable positioning, shortening the debugging time and improving exposure reproducibility. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments 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.

[0022] Figure 1 This is a simplified structural diagram of the interference exposure device in one embodiment of the present invention, wherein the dashed lines represent the adjusted positions of the components;

[0023] Figure 2 This is a three-dimensional structural schematic diagram of the interference exposure device in one embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the 10° interference angle of the interference exposure device in one embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the 30° interference angle of the interference exposure device in one embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the 90° interference angle of the interference exposure device in one embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of the beam-splitting unit of the interference exposure device in one embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram of the beam expander of the interference exposure device in one embodiment of the present invention;

[0029] Figure 8 This is a schematic diagram of the working plane of the interference exposure device in one embodiment of the present invention.

[0030] Explanation of reference numerals in the attached drawings: 1. First beam; 2. Second beam; 10. Beam generating unit; 11. Beam generator; 12. Third reflecting mirror; 13. Fourth reflecting mirror; 14. Beam expander; 15. λ / 2 waveplate; 20. Beam splitting unit; 30. Working plane; 40. Reflection unit; 41. First reflecting mirror; 42. Second reflecting mirror; 50. Linear drive mechanism; 60. λ / 4 waveplate. Detailed Implementation

[0031] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0032] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0033] Interferometric exposure is a key technology for fabricating micro / nano-periodic structures by superimposing two or more coherent beams of light onto a working plane (such as a photoresist surface) to form periodic bright and dark fringes. This technology is widely used in photonic crystals, microlens arrays, nanoimprint templates, gratings, and periodic surface structures because it eliminates the need for complex masks and is suitable for generating large-area and highly uniform structures. The spatial period of the interference fringes is closely related to the incident light wavelength and the interference angle, commonly expressed as: d = λ / (2sin(θ / 2)) (where d is the fringe period, λ is the wavelength, and θ is the angle between the two beams). Therefore, the light source wavelength and the beam angle are key parameters for improving resolution or changing the period.

[0034] Currently, most mainstream interferometric exposure platforms use red or ultraviolet light sources. In contrast, the blue light band (shorter wavelength) has a natural resolution advantage, enabling smaller fringe periods and higher structural precision, thus showing significant potential in the fabrication of high-precision micro and nanostructures. However, high-precision interferometric exposure based on blue light still faces several technical bottlenecks in practical engineering applications.

[0035] Interference requires strict spatial and temporal coherence. Traditional beam splitting methods (such as ordinary beam splitters, beam splitting prisms, or free-space optical paths) easily introduce wavefront discontinuities, optical path difference fluctuations, and mechanical vibration coupling, leading to phase drift and decreased fringe stability in interference fringes. Blue light sources (especially short-wavelength semiconductor or solid-state lasers) are more sensitive to surface shape errors and chromatic aberrations of optical components, and wavefront mismatch has a greater impact on imaging and exposure results.

[0036] Uneven intensity between the two beams significantly reduces the contrast of interference fringes, thus affecting the spatial distribution of exposure dose and the sharpness of image edges. Traditional methods using neutral density plates or variable apertures for coarse adjustment are insufficient to achieve high-precision, repeatable intensity ratios. Optical losses and scattering may be more pronounced in blue light systems, requiring even greater precision in correcting for weak light intensity differences.

[0037] The morphology and contrast of interference fringes are highly sensitive to the polarization state of the incident light. If there is a difference in direction between linearly polarized or unstable polarization directions during the interference of two beams, it will produce a non-ideal light intensity distribution, and may even cause distortion or weakening of periodic fringes.

[0038] Existing systems often rely on static polarizers or simple waveplates for polarization control, lacking the ability to dynamically adjust and compensate during exposure, and failing to adequately consider polarization dispersion and the polarization dependence of optical components.

[0039] Existing technologies employ fixed optical geometry (such as fixed supports or optical stages) to ensure stability, but this results in the interference angle being non-adjustable or having a limited adjustment range, making it difficult for the same platform to meet the fabrication requirements of structures with multiple periods (different d). The limited adjustability of the interference angle also affects the versatility and flexibility of the process, increasing the workload of changing optical platforms or realigning for different period requirements.

[0040] To achieve the above objectives and other related objectives, such as Figure 1-8 As shown, this utility model proposes an interference exposure device, including a beam generating unit 10, a beam splitting unit 20, a working plane 30, and a reflection unit 40.

[0041] The beam generating unit 10 is used to emit a beam.

[0042] The beam splitting unit 20 is disposed on the path of the beam to split the beam into a first beam 1 and a second beam 2.

[0043] The working plane 30 is used to place photoresist or other materials to be etched.

[0044] A set of reflection units 40 is provided for each of the first beam 1 and the second beam 2. The reflection units 40 are used to reflect the first beam 1 and the second beam 2 to the working plane 30 to form an interference pattern. The first beam 1 and the second beam 2 are obtained by amplitude splitting of the same laser beam. The wavefronts are continuous and the optical path difference remains stable. They interfere after meeting on the working plane 30.

[0045] The reflecting unit 40 includes a reflector and an adjustment unit. The adjustment unit is used to adjust the position of the reflector to adjust the incident angle of the first beam 1 and the second beam 2 on the working plane 30. This allows the incident angle between the two circularly polarized beams on the working plane 30 to be adjusted between 0° and 90°, and they will interfere when they meet on the working plane 30.

[0046] In this embodiment, the two beams obtained after amplitude splitting of the same laser beam remain coherent and have continuous wavefronts. They are reflected by their respective mirrors and meet at the working plane 30. The sum of the incident angles of the two beams determines the interference angle θ, and the interference fringe period is determined by d = λ / (2sin(θ / 2)). Amplitude splitting and a common path or precision matching structure ensure that the optical path difference between the two beams is within the coherence length range and stable, thereby producing high-contrast, long-term stable fringes. Coarse / fine adjustment of the incident angle is achieved through mechanical / piezoelectric adjustment of the mirrors, and the phase can be compensated for by micron-level piezoelectric displacement or phase modulator to lock the fringe position. The light intensity balancing unit ensures that the two beams have similar intensities to improve visibility. The polarization control unit adjusts the two beams to circular polarization (same chirality) or specified linear polarization to avoid decreased fringe contrast or period distortion due to polarization mismatch. During operation, closed-loop adjustment can be performed by monitoring the Fourier transform or contrast index of the interference image to achieve automated and stable exposure.

[0047] This device significantly improves interference phase stability and long-term fringe reproducibility through amplitude segmentation and wavefront continuity design, avoiding wavefront discontinuities and optical path fluctuations caused by traditional beam splitting. The adjustable 40° angle of the reflection unit allows for continuous adjustment of the interference angle within the 0°-90° range, enabling rapid and precise switching of fringe periods on the same platform and greatly enhancing fabrication versatility. Combined with precise light intensity matching and polarization optimization, high-visibility and high-uniformity exposure patterns can be obtained, reducing defects and edge blurring. Modular design and automatic control enable rapid alignment, repeatable positioning, and parameter memory functions, reducing operational complexity and debugging time, making it suitable for industrial applications of high-precision blue light micro / nanostructure fabrication (such as photonic crystals, microlens arrays, and nanoimprint templates).

[0048] In one optional embodiment of this utility model, such as Figure 2-5As shown, it also includes a linear drive mechanism 50, which drives the working plane 30 to move along the angle bisector of the angle between the two beams, ensuring that the two incident angles received by the sample remain symmetrical during the movement, thus keeping the period and direction of the interference fringes consistent throughout the entire movement path. This layout facilitates large-area exposure with a small fixed interference spot: by translating the sample along the angle bisector, locally stable interference patterns are "scanned" and covered or stitched on the sample, thereby obtaining a uniform periodic structure several meters or even larger in size. The linear guide rail has a movement range of not less than 2000 mm and a movement accuracy of not less than 0.01 mm, while the precision two-dimensional translation stage equipped on the working plane 30 can achieve high-precision positioning (also ≥0.01 mm) in a plane perpendicular to the guide rail direction. The two work together to complete a composite action of long-stroke scanning and short-stroke precise alignment / stitching. The linear drive structure can specifically be a linear motor + high-rigidity linear guide rail, a long-stroke ball screw or synchronous belt drive with high-precision guide rail, hydraulic rod, pneumatic rod, etc.

[0049] After the incident angle is adjusted, the position of the interference area is observed through the screen. If the interference area shifts, the guide rail of the working plane 30 is driven, and the working plane 30 is translated simultaneously. After ensuring that the area to be exposed is located in the center of the working plane 30, the position of the working plane 30 is fixed.

[0050] In one optional embodiment of this utility model, such as Figure 1 As shown, the reflector includes a first reflector 41 and a second reflector 42. The first reflector 41 directly receives the beam output from the beam splitter 20 and reflects the beam in a controllable direction to the second reflector 42. The second reflector 42 then directionally reflects the beam from the first reflector 41 to the working plane 30. By arranging adjustable mechanisms (such as pitch / yaw fine-tuning, linear displacement, and piezoelectric micro-displacement devices) between the two mirrors and between the second mirror and the working plane 30, coarse / fine adjustment of the incident angle, optical path fine-tuning, and phase control can be achieved without increasing the system's space footprint. The folded optical path with two mirrors connected in series has the advantages of compact structure, good mechanical rigidity, and easy installation of drivers and sensors. At the same time, a high-reflectivity dielectric film mirror suitable for the blue light band can be used to ensure high transmittance and low phase distortion.

[0051] In one optional embodiment of this utility model, such as Figure 1As shown, the adjustment unit is configured to drive the first reflector 41 and the second reflector 42 to rotate around a second direction, and the adjustment unit is configured to drive the second reflector 42 to translate along a third direction. The second direction is perpendicular to the directions of the first beam 1 and the second beam 2, and the third direction is perpendicular to the second direction. The adjustment unit includes a precision rotary table (rotating around the second direction) and an optical path difference adjustment component (translating along the third direction). The optical path difference adjustment component is used to fine-tune the optical path of the beam splitter, so that the optical path difference between the two beams in the working plane 30 is stabilized within a preset range. The optical path difference adjustment component is driven by a precision guide rail, and the movement accuracy is not less than 0.01 mm.

[0052] The adjustment unit consists of two types of motion subsystems: a precision rotary table for adjusting the incident angle and an optical path difference adjustment component for fine-tuning the optical path. The rotary table causes the first reflecting mirror 41 and the second reflecting mirror 42 to rotate about a second direction perpendicular to the beam direction (i.e., rotate about an axis perpendicular to the propagation directions of the two beams). By changing the mirror tilt angle, the incident direction and the included angle θ of the two beams on the working plane 30 can be precisely controlled. The optical path difference adjustment component translates along a precision guide rail in a third direction (orthogonal to the second direction), changing the geometric optical path of one beam at the reflecting mirror, thereby fine-tuning the optical path difference between the two beams and stabilizing it within a preset range to meet the requirements of coherent superposition. This structure clearly separates angle control and optical path control: the rotary table is mainly used for coarse adjustment and period switching (changing θ and thus changing the fringe period d), while the optical path difference adjustment component is used to eliminate phase drift caused by the optical path difference and achieve phase locking. Together, they can achieve interference conditions with high repeatability and high stability.

[0053] In use, to adjust the angle to 30°, adjust the rotating stages of the first reflecting mirror 41 and the second reflecting mirror 42 on both sides—rotate the reflecting mirror 15° clockwise and the transmitting mirror 15° counterclockwise (the angle between the two beams is the sum of the deflection angles on both sides). Simultaneously, compensate for the optical path difference using a translation stage to ensure clear and drift-free interference fringes. To adjust the angle to 90°: similarly, rotate the reflecting mirror 45° clockwise and the transmitting mirror 45° counterclockwise, using the translation stage to compensate for the optical path difference, thus completing the angle adjustment.

[0054] In one optional embodiment of this utility model, such as Figure 1 , 3As shown in Figure 5, the set of reflection units 40 corresponding to the first beam 1 and the set of reflection units 40 corresponding to the second beam 2 are arranged in a mirror-symmetric manner. This mirror-symmetric arrangement of the two sets of reflection units 40 corresponding to the first and second beams means that the two sets of optical elements are geometrically symmetrical about the system centerline (usually the normal to the working plane 30° or the angle bisector of the incident angle), and their mechanical mounting references, optical path lengths, and optical element specifications are as consistent as possible. The symmetrical layout facilitates the use of linkage control (e.g., master-slave drive or common-mode / differential-mode control strategies) during adjustment to maintain the symmetry of the incident angles of the two beams, optical path matching, and polarization / intensity consistency. This naturally reduces fringe distortion and phase errors caused by asymmetry, making the system easier to achieve large-area uniform exposure and rapid repeatable positioning. Mirror symmetry and linkage control significantly improve the symmetry and stability of the system: on the one hand, it reduces fringe tilt, periodic nonlinearity, and edge distortion caused by unilateral adjustment, improving fringe uniformity and contrast. On the other hand, master-slave synchronization and differential-mode fine-tuning enable rapid, repeatable periodic switching and large-area seamless scanning, shortening alignment time and increasing throughput. This structure has a certain self-compensation capability for thermal drift and mechanical errors (the symmetry errors partially cancel each other out), facilitating modularization and industrial integration. To achieve optimal results, it is necessary to ensure the consistency of the pairing of the left and right components, the accuracy of drive synchronization, and regular calibration and temperature control management.

[0055] In one optional embodiment of this utility model, such as Figure 1 As shown, the beam generating unit 10 includes a beam generator 11, a third reflecting mirror 12, a fourth reflecting mirror 13, a beam expander 14, and a λ / 2 waveplate 15 arranged sequentially along the beam direction. The third reflecting mirror 12 and the fourth reflecting mirror 13 are used to deflect the laser beam path, so that the laser beam is transmitted to the beam expander 14 along a preset direction. The beam expander 14 is used to expand the cross-sectional diameter of the incident laser beam to 30mm-65mm before output. The beam expansion factor of the beam expander 14 is adjustable, and the adjustment range is adapted to the varying requirements of the laser cross-sectional diameter from 30mm to 65mm. The λ / 2 waveplate 15 is used to adjust the polarization state of the beam after it has been expanded by the beam expander 14, so that the amplitudes (intensities) of the two beams subsequently split by the polarizing beam splitter (PBS) are equal. A λ / 2 waveplate 15 is positioned between the beam expander 14 and the PBS. The λ / 2 waveplate 15 rotates the polarization direction of the incident light by a certain angle. Adjusting this waveplate changes the ratio of the s-polarization component (perpendicular to the incident plane) and the p-polarization component (parallel to the incident plane) in the beam incident on the polarizing beam splitter, thereby ensuring that the amplitudes of the two beams (s-polarized light and p-polarized light) after splitting by the polarizing beam splitter are equal. Ultimately, this achieves a beam intensity that is half that of the original beam (intensity is proportional to the square of the amplitude). By precisely adjusting the amplitude of the two beams after splitting by the PBS using the λ / 2 waveplate 15, the beam intensity can be half that of the original beam, resulting in an interference fringe contrast of over 0.9 and improved clarity of the exposure pattern.

[0056] In use, fix the beam generator 11 on the optical platform, turn on the laser, and ensure that the laser beam enters the center of the third reflecting mirror 12 horizontally. Adjust the angle of the third reflecting mirror 12 so that the laser is reflected horizontally to the center of the fourth reflecting mirror 13. Then adjust the angle of the fourth reflecting mirror 13 so that the laser is transmitted horizontally to the incident center of the beam expander 14. Fix the beam expander 14 on the optical platform, ensuring that the laser is incident on the center of the beam expander 14. Adjust the azimuth angle and position of the beam expander 14 fixing bracket to ensure that the laser beam output by the beam expander 14 is collimated. Adjust the magnification knob of the beam expander 14 and observe the cross-sectional diameter of the emitted beam through the screen until the desired diameter is reached. Adjust the rotation angle of the λ / 2 waveplate 15 until the readings of the two optical power meters are both 200mw (the original beam power was 400mw, and the light intensity was 1 / 2 after splitting by the beam splitter 20), and fix the angle of the λ / 2 waveplate 15.

[0057] In an optional embodiment of this invention, the beam generator 11 emits a beam with a wavelength of 400-500 nanometers. Specifically, the beam generator 11 is used to output a continuous laser beam with a wavelength of 457 nm and a power of 400 mW. The output power fluctuation range of the blue continuous laser does not exceed ±3%, and the wavelength stability does not exceed ±1 nm. Using 457 nm blue light as the light source, compared with traditional red light (such as 632.8 nm), the interference fringe period is smaller (the fringe period is proportional to the wavelength), which can achieve higher precision micro-nano structure fabrication (resolution improvement of about 30%).

[0058] In an optional embodiment of this invention, the reflectivity of the aforementioned mirrors is not less than 99%, and the flatness error of the reflecting surface does not exceed λ / 20 (λ = 457nm). Using a 457nm, 400mW, highly stable blue light source can significantly improve the fabrication precision of micro / nano structures (period and linewidth can be reduced by approximately 30%), enabling the direct fabrication of finer photonic crystal gratings, submicron gratings, and high-density microstructures. The actual effect is limited by the bandwidth of optical components, optical path alignment, light intensity equalization, photoresist resolution, and absorption characteristics: blue light is typically more strongly absorbed by various photoresists. High coherence can lead to speckle, which needs to be mitigated through multiple exposures, vibration / rotation phase averaging, or decoherence techniques. Overall, reasonable laser specifications and closed-loop power / phase control, along with optical components and process matching optimized for 457nm, can achieve higher resolution, smaller period, and good repeatability, meeting the needs of high-precision industrial micro / nano fabrication.

[0059] In one optional embodiment of this utility model, such as Figure 1As shown, the incident angle of the light beam entering the third reflecting mirror 12 and the fourth reflecting mirror 13 is 45°. That is, the light beam is folded back 180 degrees after two reflections, thus saving space. Setting the incident angle of the third reflecting mirror 12 and the fourth reflecting mirror 13 to 45° and folding the light beam back 180° after two reflections is actually using two plane mirrors or equivalent reflectors arranged at 90° to each other to "fold back" the light path, achieving a compact folding of the light path. This arrangement can send the light beam back to the opposite direction of its original direction without changing the incident / exit height and the approximate optical path, thereby saving system length and making the device layout more compact. In systems that implement interferometric exposure, this folding structure is often used to save stage space, fold the light path into a limited optical base, or achieve a symmetrical geometric layout (e.g., guiding the light beam back to the reflecting unit 40 symmetrical to another light beam).

[0060] In one optional embodiment of this utility model, such as Figure 1 As shown, a λ / 4 waveplate 60 (quarter-wave plate) is disposed between the beam splitting unit 20 and the reflecting unit 40. Both the λ / 2 waveplate 15 and the λ / 4 waveplate 60 are made of quartz material, and the aperture of the waveplate is not less than the maximum cross-sectional diameter of the laser beam after beam expansion.

[0061] The addition of a λ / 4 (quarter-wave plate) between the beam splitting unit 20 and the reflecting unit 40 is to address the spatial non-uniformity of interference intensity caused by differences in polarization states due to inconsistent polarization directions or specular reflection in the optical paths after beam splitting. Specifically, a λ / 4 wave plate 60 is placed in each beam-splitting optical path, causing the incident linearly polarized light to be converted to circularly polarized light when the fast axis of the wave plate forms a 45° angle with the incident polarization direction. If both arms are circularly polarized and maintain the same chirality (or relative chirality as designed) upon reaching the working plane 30, the dependence on polarization direction during beam superposition is eliminated, resulting in a more uniform interference fringe intensity distribution on the working plane 30. This, combined with a previously or parallel λ / 2 wave plate 15 (quartz) used to rotate the linear polarization direction before beam splitting, serves as a convenient means of placing the linear polarization at a 45° position on the λ / 4 fast axis. It is essential that the wave plate material, aperture, and surface / coating specifications match the system operating conditions to avoid introducing additional scattering or wavefront distortion. Adding a λ / 4 waveplate 60 can significantly improve the spatial uniformity and contrast of interference fringes, eliminate polarization mismatch caused by differences in the polarization direction of the incident rays or by devices, reduce local unevenness in brightness and darkness in the fringes and decrease in visibility, thereby improving the uniform exposure of the pattern and the process yield.

[0062] In an optional embodiment of this invention, the beam splitting unit 20 is a polarizing beam splitter (PBS). The polarizing beam splitter is used to split the incident beam into two linearly polarized beams with mutually perpendicular polarization directions, wherein the reflected light is s-polarized linearly polarized light and the transmitted light is p-polarized linearly polarized light. The polarizing beam splitter has a reflectivity of not less than 99% for s-polarized light, a transmittance of not less than 99% for p-polarized light, and a polarization extinction ratio of not less than 1000:1. Using a polarizing beam splitter (PBS) for amplitude splitting ensures that the two light sources originate from the same incident light source, with continuous wavefronts and consistent temporal coherence. Combined with high-precision adjustment of the reflecting mirror, the optical path difference between the two beams can be kept stable over a long period, avoiding interference fringe drift.

[0063] In summary, this invention achieves high-contrast, long-term stable, and repeatable interference fringe generation and large-area uniform exposure through amplitude-segmented co-source optical paths, polarization and phase compensation, mirror folding and mirror group mirror symmetry arrangement, and precise angle / optical path linkage control. The use of PBS+λ / 2 / λ / 4 polarization management ensures polarization matching between the two arms and achieves near-ideal energy distribution. After beam splitting, the wavefront is continuous, and the optical path difference can be finely adjusted and locked in a closed loop via a 0.01mm precision guide rail and translation component along a third direction. The rotating stage allows for continuous and repeatable adjustment of the incident angle within the 0°-90° range, enabling rapid switching of the fringe period (d=λ / (2sin(θ / 2))). It employs a stable 457nm blue laser with high reflectivity (≥99%) and high flatness (≤λ / 20). The mirrors significantly reduce the fringe period and linewidth (improving resolution by approximately 30%) while maintaining low loss and excellent wavefront quality. The tandem folding of the two mirrors and the 45° folding structure result in a compact optical path, high mechanical rigidity, and easy modular installation. Mirror symmetry and linkage control reduce asymmetric errors and improve the self-compensation capability for thermal / mechanical drift. Combined with a 30-65mm adjustable beam expander and a long-stroke (≥2000mm, accuracy ≥0.01mm) linear scanning mechanism, seamless scanning exposure over meter-scale or larger areas can be achieved with a small spot size. Overall, this device balances resolution, stability, adjustability, and industrial integration capabilities, making it suitable for micro / nano structure fabrication and high-throughput exposure processes requiring high phase stability and fringe controllability. Furthermore, closed-loop power / phase control and speckle suppression strategies further improve yield and repeatability.

[0064] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

[0065] Throughout this specification, references to "an embodiment," "an embodiment," or "a specific embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention, but not necessarily in all embodiments. Therefore, the various representations of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic of any specific embodiment of the present invention can be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the present invention described and illustrated herein may be based on the teachings herein and will be considered part of the spirit and scope of the present invention.

Claims

1. An interference exposure apparatus, characterized in that, include: Beam generating unit, used to emit a beam; A beam splitting unit is disposed in the path of the beam to split the beam into a first beam and a second beam; The working surface is used to place the material to be etched. A set of reflection units is provided for the first beam and the second beam respectively. The reflection units are used to reflect the first beam and the second beam to the working plane to form an interference pattern. The reflection unit includes a reflector and an adjustment unit. The adjustment unit is used to adjust the position of the reflector to adjust the incident angle of the first beam and the second beam on the working plane.

2. The interferometric exposure apparatus according to claim 1, characterized in that, It also includes a linear drive mechanism for driving the working plane to move along a first direction, which is the bisector of the angle between the first beam and the second beam.

3. The interference exposure apparatus according to claim 1, characterized in that, The reflector includes a first reflector and a second reflector. The first reflector is used to receive the light beam emitted from the beam splitter, and the second reflector is used to receive the light beam reflected by the first reflector.

4. The interference exposure apparatus according to claim 3, characterized in that, The adjustment unit is configured to drive the first reflector and the second reflector to rotate around a second direction, and the adjustment unit is configured to drive the second reflector to translate along a third direction, the second direction being perpendicular to the directions of the first beam and the second beam, and the third direction being perpendicular to the second direction.

5. The interference exposure apparatus according to claim 4, characterized in that, The set of reflecting units corresponding to the first beam and the set of reflecting units corresponding to the second beam are arranged in a mirror-symmetric manner.

6. The interferometric exposure apparatus according to claim 1, characterized in that, The beam generating unit includes a beam generator, a third reflecting mirror, a fourth reflecting mirror, a beam expander, and a λ / 2 waveplate arranged sequentially along the beam direction.

7. The interferometric exposure apparatus according to claim 6, characterized in that, The incident angle of the light beam entering the third and fourth reflecting mirrors is 45°.

8. The interference exposure apparatus according to claim 6, characterized in that, The beam emitted by the beam generator has a wavelength of 400-500 nanometers.

9. The interferometric exposure apparatus according to claim 1, characterized in that, A λ / 4 waveplate is disposed between the beam splitting unit and the reflecting unit.

10. The interferometric exposure apparatus according to claim 1, characterized in that, The beam splitting unit is a polarizing beam splitter prism.

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