A deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of beam expander.

Abstract

This invention relates to the field of deep ultraviolet laser precision detection technology, specifically to a deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander. The device includes: a laser fixing module for fixing the deep ultraviolet laser to provide a constant-direction laser beam incidence; and a beam expander translational adjustment module for supporting the beam expander and driving it to perform pure translational motion in a plane perpendicular to the laser beam incidence direction. This invention utilizes the structural characteristic that the beam expander's aperture is much larger than the required laser incident diameter. By dynamically adjusting the relative position of the beam expander and the incident mirror, it achieves switching of the beam expander's effective working area, actively avoiding areas of light pollution. This ensures that the optical path and optical axis do not shift during adjustment, and the interferometer performance is not affected, achieving in-situ avoidance of polluted areas and avoiding optical axis calibration errors and secondary debugging costs associated with traditional methods.

Description

Technical Field

[0001] This invention relates to the field of deep ultraviolet laser precision detection technology, specifically to a deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of the beam expander. Background Technology

[0002] Deep ultraviolet lasers, due to their short wavelength and high photon energy, have become the core light source for ultra-high resolution interferometry. However, their high energy density characteristics make them prone to photochemical reactions with trace residues on the surface of optical components and the materials themselves, inducing laser-induced contamination (LIP). This leads to an irreversible decrease in the transmittance of optical components and enhanced scattering, directly affecting the measurement accuracy, stability, and overall performance of the interferometer.

[0003] As the key optical component in a deep-ultraviolet laser interferometer that first achieves beam diameter expansion, the beam expander is the part with the highest optical power density in the laser path. Furthermore, the laser is consistently focused onto its fixed area, making it the core component most prone to and causing the most severe light pollution. Current technologies for addressing beam expander light pollution are all reactive and have significant drawbacks. Traditional cleaning methods require removing the contaminated beam expander from the interferometer's optical path for high-precision cleaning. This process can easily cause optical axis misalignment, and the optical path needs to be readjusted after cleaning. This is time-consuming and labor-intensive, significantly extending the equipment maintenance cycle and affecting production and testing efficiency.

[0004] Lens replacement method: Directly replacing the contaminated beam expander can quickly restore the optical path performance, but the special beam expander for the deep ultraviolet band is a high-precision optical component with a high cost. Frequent replacement will cause great cost waste, and the optical axis still needs to be calibrated after replacement, which poses a risk of secondary error.

[0005] No in-situ pollution avoidance methods: Existing technologies do not consider using the structural characteristics of beam expanders to achieve active avoidance of contaminated areas, but only focus on "post-contamination treatment" and do not solve the problem from the perspective of "continuous use and in-situ avoidance", which cannot meet the long-term, continuous and stable working requirements of deep ultraviolet laser interferometers.

[0006] Limitations of auxiliary protection methods: Existing protection methods such as inert gas purging and selection of ultra-low gas release materials can only slow down the rate of contamination of the beam expander, but cannot fundamentally prevent contamination from occurring. Ultimately, the contamination problem still needs to be solved by cleaning / replacing, and the technical bottleneck of traditional protection has not been broken.

[0007] In summary, a deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of the beam expander needs to be proposed to solve the above problems. Summary of the Invention

[0008] The purpose of this invention is to provide a deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander, so as to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: This invention proposes a deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander, comprising: A laser fixing module is used to fix a deep ultraviolet laser to provide laser beam incident in a constant direction; A beam expander translation adjustment module is used to support the beam expander and drive the beam expander to perform pure translation in a plane perpendicular to the incident direction of the laser beam, so as to switch the incident area of ​​the laser beam on the beam expander and avoid the contaminated area. A spot coverage monitoring module is arranged in a non-contact manner on the optical path after beam expansion, and is used to monitor in real time whether the expanded spot effectively covers the first lens of the interferometer. An electronically controlled drive module is connected to a beam expander translation adjustment module and is used to receive commands and drive it to perform precise displacement. The main control unit is connected to the electronically controlled drive module, the light spot coverage monitoring module, and the deep ultraviolet laser interferometer body. It is used to receive pollution signals or user commands from the interferometer body to start the avoidance program, issue displacement commands to the electronically controlled drive module according to the preset target clean area coordinates, and receive feedback signals from the light spot coverage monitoring module in real time. When the light spot coverage is determined to be qualified, it controls the electronically controlled drive module to stop driving and lock the position, forming a closed-loop control.

[0010] Preferably, the beam expander translation adjustment module includes: A beam expander holder, which is used to hold the beam expander without stress. A two-dimensional precision electric displacement stage is connected to a beam expander fixture and is used to provide translational degrees of freedom only in the X and Y axes. Its translational accuracy is less than or equal to 10 μm, its stroke is 0 to 50 mm, and there is no angular deflection during the translation process. A limiting component, comprising a mechanical limit and a photoelectric limit, is used to prevent the two-dimensional precision electric displacement stage from overtraveling; A fixed base is used to rigidly connect the beam expander translation adjustment module to the interferometer frame.

[0011] Preferably, the light spot coverage monitoring module includes: A spot monitoring unit, which consists of a non-contact camera arranged in a side-axis manner, does not interfere with the main optical path; The beam spot position determination module has a built-in image recognition algorithm to calculate the overlap area between the beam-expanded beam spot and the first lens of the interferometer, and outputs a "coverage qualified" or "coverage unqualified" signal to the main control unit according to a preset minimum qualified coverage ratio threshold.

[0012] Preferably, the logic for determining whether the light spot coverage monitoring module is qualified is based on the following formula: ; In the formula, The actual coverage ratio of the light spot is expressed as a percentage, without units; it directly reflects the degree of overlap between the light spot and the lens. The larger the value, the more complete the coverage. The overlap area between the expanded beam spot and the first lens of the interferometer, expressed in mm², is calculated by the image recognition algorithm of the beam spot coverage monitoring module and is the core parameter for judging the coverage effect. The effective light-transmitting area of ​​the first lens of the interferometer, measured in mm², is an inherent parameter of the interferometer, preset in the spot coverage monitoring module, and requires no user adjustment. Minimum acceptable coverage ratio, unitless, expressed as a percentage; it is the threshold for judging whether the light spot coverage is acceptable, typically 80%, that is, the light spot overlap area is ≥ 80% of the effective lens area, then the coverage is considered acceptable; The decision logic is: when the calculated If the light spot coverage is ≥80%, it indicates that the light spot coverage is qualified, and the main control unit issues a stop adjustment command; if If the coverage is less than 80%, continue to adjust the position of the beam expander until the coverage requirement is met.

[0013] Preferably, the main control unit uses the following formula when calculating the displacement required to switch from the current contaminated area to the target clean area: ; ; In the formula, The final distance the beam expander needs to move along the X-axis, measured in μm; a positive value indicates movement along the positive X-axis, and a negative value indicates movement along the negative X-axis, directly determining the beam expander's position adjustment along the X-axis. The final distance the beam expander needs to move along the Y-axis, in μm; a positive value = movement along the positive Y-axis, a negative value = movement along the negative Y-axis, and... In conjunction with this, the two-dimensional position of the beam expander can be adjusted. : X-axis coordinates of the target clean area, in μm; these are user-preset or main control unit stored clean area location parameters, which can be customized according to the beam expander specifications. : The Y-axis coordinate of the target clean area, in μm; and Correspondingly, these elements together constitute the two-dimensional position of the target clean area, ensuring that the laser is incident on the clean section of the beam expander. : The X-axis coordinates of the current contaminated area of ​​the beam expander, in μm; acquired and stored in real time by the main control unit, serving as the reference parameter for displacement calculation. : The Y-axis coordinate of the current contaminated area of ​​the beam expander, in μm; and Correspondingly, the two-dimensional positions of the current polluted area are used to calculate the displacement difference. X-axis displacement compensation, measured in μm; used to compensate for system errors in the electronically controlled drive module and transmission mechanism, typically ranging from 0 to 5 μm. Calibration is performed based on actual transmission accuracy to ensure more precise displacement. : Y-axis displacement compensation, in μm; and They serve the same purpose: to compensate for transmission errors in the Y-axis direction and ensure the accuracy of Y-axis displacement.

[0014] Preferably, the main control unit includes a pollution level quantification module, which is used to quantify the pollution level according to the formula: ; In the formula, The current level of contamination in the area indicated by the beam expander is expressed as a percentage, without units. The higher the value, the more severe the contamination, and the more necessary it is to initiate an avoidance procedure. When the beam expander is clean and free of contamination, the transmitted power of the laser is expressed in mW; it is a baseline parameter stored after the initial calibration of the equipment, serving as a standard for comparison against contamination. The actual laser transmission power in the current area of ​​the beam expander is measured in mW. It is collected in real time by the interferometer's built-in detection system and directly reflects the pollution level in the current area. The heavier the pollution, the lower the transmission power. The judgment logic is as follows: preset pollution threshold A typical value is 15%. ≥15% indicates severe pollution, triggering a prompt from the main control unit to remind the user to initiate an avoidance procedure; when If the pollution level is less than 15%, it indicates that the pollution is minor and the current area can continue to be used without any adjustments.

[0015] Preferably, the device further includes a human-machine interaction unit connected to the main control unit, including buttons or a touch screen for manually controlling displacement and setting parameters, a status display screen for displaying the position of the beam expander, the light spot status and the working mode, and an audible and visual alarm module triggered in abnormal situations.

[0016] Preferably, all components of the laser fixing module and the beam expander translation adjustment module of the device are made of ultra-low gas release and UV protection materials specifically for the deep ultraviolet band, so as to avoid introducing additional contaminants into the optical path.

[0017] Preferably, the electronically controlled drive module includes an X / Y axis stepper or servo motor, a motor driver, a linear guide and a ball screw transmission mechanism, and a positioning self-locking mechanism; the positioning self-locking mechanism locks the beam expander translation adjustment module after the main control unit issues a stop command to prevent position drift.

[0018] This invention also proposes a deep ultraviolet laser interferometer avoidance method based on dynamic adjustment of the beam expander, applied to the aforementioned device, comprising the following steps: S1. Pollution determination: The main control unit receives the signal emitted by the interferometer body due to performance degradation or the pollution signal confirmed by manual verification, and determines that light pollution has occurred in the current laser incident area of ​​the beam expander. S2. Adjustment Start-up: The user starts the contamination avoidance program through the human-machine interaction unit, and the main control unit retrieves the preset or manually input target clean area coordinates; S3. Dynamic translational adjustment: The main control unit controls the electronically controlled drive module to drive the beam expander translational adjustment module to perform pure translation based on the coordinates of the target clean area, so that the laser incident point moves from the contaminated area to the target clean area. During the adjustment process, the laser fixing module remains stationary and the beam expander does not deflect at any angle. S4. Spot Coverage Monitoring: During the adjustment process, the spot coverage monitoring module acquires the spot image after beam expansion in real time and calculates its coverage ratio with the first lens of the interferometer. S5. Position Locking: When the main control unit receives a signal that the coverage ratio is qualified, it immediately controls the electronic control drive module to stop driving and starts the position self-locking mechanism to lock the current position of the beam expander and complete the in-situ avoidance of the contaminated area; S6. Resumption of Operation: The interferometer directly utilizes the laser emitted from the clean area of ​​the beam expander to resume normal detection operation without the need for additional optical path calibration.

[0019] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention utilizes the structural characteristic that the aperture of the beam expander is much larger than the required laser incident diameter. By dynamically adjusting the relative position of the beam expander and the incident mirror, the effective working area of ​​the beam expander can be switched, actively avoiding areas where light pollution has occurred. There is no need to disassemble, clean, or replace the beam expander. It ensures that the optical path and optical axis do not shift during the adjustment process, and the performance of the interferometer is not affected. It achieves in-situ avoidance of polluted areas, avoids optical axis calibration errors and secondary debugging costs caused by traditional processing methods, extends the effective working life of the beam expander, reduces the replacement frequency of high-precision optical lenses, and significantly reduces the maintenance cost and equipment downtime of the deep ultraviolet laser interferometer. The device has a simple structure, precise control, and can achieve automated adjustment. It is suitable for the long-term, continuous, and stable operation requirements of the deep ultraviolet laser interferometer and is easy to integrate into existing interferometer equipment, with strong compatibility. Attached Figure Description

[0020] Figure 1 This is a flowchart of the avoidance method of the deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of the beam expander according to the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1, please refer to Figure 1 This invention proposes a deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander, comprising: A laser fixing module is used to fix a deep ultraviolet laser to provide laser beam incident in a constant direction; A beam expander translation adjustment module is used to support the beam expander and drive the beam expander to perform pure translation in a plane perpendicular to the incident direction of the laser beam, so as to switch the incident area of ​​the laser beam on the beam expander and avoid the contaminated area. A spot coverage monitoring module is arranged in a non-contact manner on the optical path after beam expansion, and is used to monitor in real time whether the expanded spot effectively covers the first lens of the interferometer. An electronically controlled drive module is connected to a beam expander translation adjustment module and is used to receive commands and drive it to perform precise displacement. The main control unit is connected to the electronically controlled drive module, the light spot coverage monitoring module, and the deep ultraviolet laser interferometer body. It is used to receive pollution signals or user commands from the interferometer body to start the avoidance program, issue displacement commands to the electronically controlled drive module according to the preset target clean area coordinates, and receive feedback signals from the light spot coverage monitoring module in real time. When the light spot coverage is determined to be qualified, it controls the electronically controlled drive module to stop driving and lock the position, forming a closed-loop control.

[0023] In a specific embodiment, it should also be noted that the beam expander translation adjustment module includes: A beam expander holder, which is used to hold the beam expander without stress. A two-dimensional precision electric displacement stage is connected to a beam expander fixture and is used to provide translational degrees of freedom only in the X and Y axes. Its translational accuracy is less than or equal to 10 μm, its stroke is 0 to 50 mm, and there is no angular deflection during the translation process. A limiting component, comprising a mechanical limit and a photoelectric limit, is used to prevent the two-dimensional precision electric displacement stage from overtraveling; A fixed base is used to rigidly connect the beam expander translation adjustment module to the interferometer frame.

[0024] In one specific embodiment, it should also be noted that the light spot coverage monitoring module includes: A spot monitoring unit, which consists of a non-contact camera arranged in a side-axis manner, does not interfere with the main optical path; The beam spot position determination module has a built-in image recognition algorithm to calculate the overlap area between the beam-expanded beam spot and the first lens of the interferometer, and outputs a "coverage qualified" or "coverage unqualified" signal to the main control unit according to a preset minimum qualified coverage ratio threshold.

[0025] In a specific embodiment, it should also be noted that the logic for the light spot coverage monitoring module to determine whether the coverage is qualified is based on the following formula: ; In the formula, The actual coverage ratio of the light spot is expressed as a percentage, without units; it directly reflects the degree of overlap between the light spot and the lens. The larger the value, the more complete the coverage. The overlap area between the expanded beam spot and the first lens of the interferometer, expressed in mm², is calculated by the image recognition algorithm of the beam spot coverage monitoring module and is the core parameter for judging the coverage effect. The effective light-transmitting area of ​​the first lens of the interferometer, measured in mm², is an inherent parameter of the interferometer, preset in the spot coverage monitoring module, and requires no user adjustment. Minimum acceptable coverage ratio, unitless, expressed as a percentage; it is the threshold for judging whether the light spot coverage is acceptable, typically 80%, that is, the light spot overlap area is ≥ 80% of the effective lens area, then the coverage is considered acceptable; The decision logic is: when the calculated If the light spot coverage is ≥80%, it indicates that the light spot coverage is qualified, and the main control unit issues a stop adjustment command; if If the coverage is less than 80%, continue to adjust the position of the beam expander until the coverage requirement is met.

[0026] In a specific embodiment, it should also be noted that the main control unit uses the following formula when calculating the displacement required to switch from the current contaminated area to the target clean area: ; ; In the formula, The final distance the beam expander needs to move along the X-axis, measured in μm; a positive value indicates movement along the positive X-axis, and a negative value indicates movement along the negative X-axis, directly determining the beam expander's position adjustment along the X-axis. The final distance the beam expander needs to move along the Y-axis, in μm; a positive value = movement along the positive Y-axis, a negative value = movement along the negative Y-axis, and... In conjunction with this, the two-dimensional position of the beam expander can be adjusted. : X-axis coordinates of the target clean area, in μm; these are user-preset or main control unit stored clean area location parameters, which can be customized according to the beam expander specifications. : The Y-axis coordinate of the target clean area, in μm; and Correspondingly, these elements together constitute the two-dimensional position of the target clean area, ensuring that the laser is incident on the clean section of the beam expander. : The X-axis coordinates of the current contaminated area of ​​the beam expander, in μm; acquired and stored in real time by the main control unit, serving as the reference parameter for displacement calculation. : The Y-axis coordinate of the current contaminated area of ​​the beam expander, in μm; and Correspondingly, the two-dimensional positions of the current polluted area are used to calculate the displacement difference. X-axis displacement compensation, measured in μm; used to compensate for system errors in the electronically controlled drive module and transmission mechanism, typically ranging from 0 to 5 μm. Calibration is performed based on actual transmission accuracy to ensure more precise displacement. : Y-axis displacement compensation, in μm; and They serve the same purpose: to compensate for transmission errors in the Y-axis direction and ensure the accuracy of Y-axis displacement.

[0027] In one specific embodiment, it should also be noted that the main control unit includes a pollution level quantification module, which is used to quantify the pollution level according to the formula: ; In the formula, The current level of contamination in the area indicated by the beam expander is expressed as a percentage, without units. The higher the value, the more severe the contamination, and the more necessary it is to initiate an avoidance procedure. When the beam expander is clean and free of contamination, the transmitted power of the laser is expressed in mW; it is a baseline parameter stored after the initial calibration of the equipment, serving as a standard for comparison against contamination. The actual laser transmission power in the current area of ​​the beam expander is measured in mW. It is collected in real time by the interferometer's built-in detection system and directly reflects the pollution level in the current area. The heavier the pollution, the lower the transmission power. The judgment logic is as follows: preset pollution threshold A typical value is 15%. ≥15% indicates severe pollution, triggering a prompt from the main control unit to remind the user to initiate an avoidance procedure; when If the pollution level is less than 15%, it indicates that the pollution is minor and the current area can continue to be used without any adjustments.

[0028] In one specific embodiment, it should also be noted that the device further includes a human-machine interaction unit connected to the main control unit, including buttons or a touch screen for manually controlling displacement and setting parameters, a status display screen for displaying the position of the beam expander, the light spot status and the working mode, and an audible and visual alarm module triggered in abnormal situations.

[0029] In a specific embodiment, it should also be noted that all components of the laser fixing module and the beam expander translation adjustment module of the device are made of ultra-low gas release and UV protection materials specifically for the deep ultraviolet band, in order to avoid introducing additional contaminants into the optical path.

[0030] In a specific embodiment, it should also be noted that the electronically controlled drive module includes an X / Y axis stepper or servo motor, a motor driver, a linear guide and a ball screw transmission mechanism, and a positioning self-locking mechanism; the positioning self-locking mechanism locks the beam expander translation adjustment module after the main control unit issues a stop command to prevent position drift.

[0031] Example 2, please refer to Figure 1 In practical applications, based on the device, this invention also proposes a method for avoiding deep ultraviolet laser interferometers based on dynamic adjustment of the beam expander, including the following steps: S1. Pollution determination: The main control unit receives the signal emitted by the interferometer body due to performance degradation or the pollution signal confirmed by manual verification, and determines that light pollution has occurred in the current laser incident area of ​​the beam expander. S2. Adjustment Start-up: The user starts the contamination avoidance program through the human-machine interaction unit, and the main control unit retrieves the preset or manually input target clean area coordinates; S3. Dynamic translational adjustment: The main control unit controls the electronically controlled drive module to drive the beam expander translational adjustment module to perform pure translation based on the coordinates of the target clean area, so that the laser incident point moves from the contaminated area to the target clean area. During the adjustment process, the laser fixing module remains stationary and the beam expander does not deflect at any angle. S4. Spot Coverage Monitoring: During the adjustment process, the spot coverage monitoring module acquires the spot image after beam expansion in real time and calculates its coverage ratio with the first lens of the interferometer. S5. Position Locking: When the main control unit receives a signal that the coverage ratio is qualified, it immediately controls the electronic control drive module to stop driving and starts the position self-locking mechanism to lock the current position of the beam expander and complete the in-situ avoidance of the contaminated area; S6. Resumption of Operation: The interferometer directly utilizes the laser emitted from the clean area of ​​the beam expander to resume normal detection operation without the need for additional optical path calibration.

[0032] Through the above steps, the effective aperture of the beam expander is much larger than the required output laser diameter. The laser only enters and expands the beam in a fixed local area of ​​the beam expander, which is the only area where light pollution occurs. By precisely and dynamically adjusting the relative position of the laser and the beam expander, the laser incident point is switched within the clean area of ​​the beam expander. The beam expansion is completed using the uncontaminated area of ​​the beam expander, completely avoiding the contaminated area. Furthermore, the subsequent main optical path does not participate in the adjustment process, ensuring that the beam expansion effect and the performance of the subsequent optical path are not affected. The system includes a beam expander translational adjustment module, a laser fixing module, a spot coverage monitoring module, an electronically controlled drive module, and a main control unit. All modules are integrated into the optical path segment between the laser and the beam expander in the deep ultraviolet laser interferometer, achieving integrated operation of "position adjustment - optical axis monitoring - precise control." In summary, this invention addresses the core pain point of light pollution from the beam expander in deep ultraviolet laser interferometers, breaking through the traditional reactive approach of "cleaning / replacing after pollution." It pioneers a "contamination area avoidance in situ based on dynamic adjustment of the beam expander" technical solution, which, compared to existing technologies, offers the following significant and substantial advantages: In-situ avoidance of contamination without disassembly / replacement of lenses: By utilizing the large-aperture characteristics of the beam expander, the relative position of the beam expander and the laser is dynamically adjusted to avoid contamination areas. No disassembly, cleaning or replacement of the beam expander is required throughout the process, which completely solves the problems of optical axis offset and secondary calibration caused by traditional processing methods and ensures the stability of the interferometer's optical path.

[0033] By eliminating coaxial constraints, the debugging difficulty is greatly reduced: the laser and interferometer optical paths are not required to be strictly coaxial. It can work normally as long as the beam-expanded spot covers the first reflector. This significantly reduces the technical threshold for equipment installation and debugging, and eliminates the need for professional high-precision optical path calibration personnel.

[0034] Significantly extend the lifespan of the beam expander and reduce maintenance costs: By switching clean areas multiple times, the effective light transmission diameter of the beam expander is fully utilized, increasing its effective working lifespan several times over, reducing the frequency of replacing high-precision deep ultraviolet optical lenses, and significantly reducing equipment maintenance and consumable costs.

[0035] Shorten maintenance cycles and improve equipment utilization: The process of avoiding contaminated areas is an automated in-situ operation with a single adjustment time of ≤5 minutes. Compared with the traditional maintenance cycle of several hours or even several days for cleaning / replacing lenses, the equipment downtime is greatly reduced, and the detection efficiency and equipment utilization are significantly improved.

[0036] Simple structure, precise control, and strong compatibility: The device is composed of modular components, with a compact structure and small size. It can be directly integrated into the optical path between the laser and the beam expander of an existing deep ultraviolet laser interferometer without requiring major modifications to the original structure of the interferometer. It has extremely high adaptability and scalability.

[0037] Easy to operate and highly safe: The main control unit supports manual / automatic dual-mode switching, and has status display, abnormal alarm and limit protection functions. It can be operated without professional personnel, and avoids the risk of equipment damage such as overtravel collision.

[0038] Adapted to the characteristics of the deep ultraviolet band, with no additional pollution introduction: All components of the device are made of ultra-low gas release and UV protection materials specifically for the deep ultraviolet band, with no organic gas release and no dust shedding, avoiding the introduction of additional pollutants into the optical path by the device itself, and meeting the ultra-clean working requirements of the deep ultraviolet laser interferometer.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander, characterized in that, include: A laser fixing module is used to fix a deep ultraviolet laser to provide laser beam incident in a constant direction; A beam expander translation adjustment module is used to support the beam expander and drive the beam expander to perform pure translation in a plane perpendicular to the incident direction of the laser beam, so as to switch the incident area of ​​the laser beam on the beam expander and avoid the contaminated area. A spot coverage monitoring module is arranged in a non-contact manner on the optical path after beam expansion, and is used to monitor in real time whether the expanded spot effectively covers the first lens of the interferometer. An electronically controlled drive module is connected to a beam expander translation adjustment module and is used to receive commands and drive it to perform precise displacement. The main control unit is connected to the electronically controlled drive module, the light spot coverage monitoring module, and the deep ultraviolet laser interferometer body. It is used to receive pollution signals or user commands from the interferometer body to start the avoidance program, issue displacement commands to the electronically controlled drive module according to the preset target clean area coordinates, and receive feedback signals from the light spot coverage monitoring module in real time. When the light spot coverage is determined to be qualified, it controls the electronically controlled drive module to stop driving and lock the position, forming a closed-loop control.

2. The deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander according to claim 1, characterized in that, The beam expander translation adjustment module includes: A beam expander holder, which is used to hold the beam expander without stress. A two-dimensional precision electric displacement stage is connected to a beam expander fixture and is used to provide translational degrees of freedom only in the X and Y axes. Its translational accuracy is less than or equal to 10 μm, its stroke is 0 to 50 mm, and there is no angular deflection during the translation process. A limiting component, comprising a mechanical limit and a photoelectric limit, is used to prevent the two-dimensional precision electric displacement stage from overtraveling; A fixed base is used to rigidly connect the beam expander translation adjustment module to the interferometer frame.

3. The deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander according to claim 1, characterized in that, The light spot coverage monitoring module includes: A spot monitoring unit, which consists of a non-contact camera arranged in a side-axis manner, does not interfere with the main optical path; The beam spot position determination module has a built-in image recognition algorithm to calculate the overlap area between the beam-expanded beam spot and the first lens of the interferometer, and outputs a "coverage qualified" or "coverage unqualified" signal to the main control unit according to a preset minimum qualified coverage ratio threshold.

4. The deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander according to claim 3, characterized in that, The logic for determining whether the light spot coverage monitoring module is qualified is based on the following formula: ； In the formula, The actual coverage ratio of the light spot is expressed as a percentage, without units; it directly reflects the degree of overlap between the light spot and the lens. The larger the value, the more complete the coverage. The overlap area between the expanded beam spot and the first lens of the interferometer, expressed in mm², is calculated by the image recognition algorithm of the beam spot coverage monitoring module and is the core parameter for judging the coverage effect. The effective light-transmitting area of ​​the first lens of the interferometer, measured in mm², is an inherent parameter of the interferometer, preset in the spot coverage monitoring module, and requires no user adjustment. Minimum acceptable coverage ratio, unitless, expressed as a percentage; it is the threshold for judging whether the light spot coverage is acceptable, typically 80%, that is, the light spot overlap area is ≥ 80% of the effective lens area, then the coverage is considered acceptable; The decision logic is: when the calculated If the light spot coverage is ≥80%, it indicates that the light spot coverage is qualified, and the main control unit issues a stop adjustment command; if If the coverage is less than 80%, continue to adjust the position of the beam expander until the coverage requirement is met.

5. The deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander according to claim 1, characterized in that, The main control unit uses the following formula when calculating the displacement required to switch from the current contaminated area to the target clean area: ； ； In the formula, The final distance the beam expander needs to move along the X-axis, measured in μm; a positive value indicates movement along the positive X-axis, and a negative value indicates movement along the negative X-axis, directly determining the beam expander's position adjustment along the X-axis. The final distance the beam expander needs to move along the Y-axis, in μm; a positive value = movement along the positive Y-axis, a negative value = movement along the negative Y-axis, and... In conjunction with this, the two-dimensional position of the beam expander can be adjusted. : X-axis coordinates of the target clean area, in μm; These are user-preset or main control unit stored clean area location parameters, which can be customized according to the beam expander specifications. : The Y-axis coordinate of the target clean area, in μm; and Correspondingly, these elements together constitute the two-dimensional position of the target clean area, ensuring that the laser is incident on the clean section of the beam expander. : The X-axis coordinates of the current contaminated area of ​​the beam expander, in μm; acquired and stored in real time by the main control unit, serving as the reference parameter for displacement calculation. : The Y-axis coordinate of the current contaminated area of ​​the beam expander, in μm; and Correspondingly, the two-dimensional positions of the current polluted area are used to calculate the displacement difference. X-axis displacement compensation, in μm; Used to compensate for system errors in electronically controlled drive modules and transmission mechanisms, with typical values ​​ranging from 0 to 5 μm. Calibration is performed based on actual transmission accuracy to ensure more precise displacement. Y-axis displacement compensation, in μm; and They serve the same purpose: to compensate for transmission errors in the Y-axis direction and ensure the accuracy of Y-axis displacement.

6. The deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander according to claim 1, characterized in that, The main control unit includes a pollution level quantification module, which is used to quantify the pollution level according to the formula: ； In the formula, The current level of contamination in the area indicated by the beam expander is expressed as a percentage, without units. The higher the value, the more severe the contamination, and the more necessary it is to initiate an avoidance procedure. When the beam expander is clean and free of contamination, the transmitted power of the laser is expressed in mW. These are the baseline parameters stored after the initial calibration of the equipment, serving as a standard for contamination comparison; The actual laser transmission power in the current area of ​​the beam expander is measured in mW. It is collected in real time by the interferometer's built-in detection system and directly reflects the pollution level in the current area. The heavier the pollution, the lower the transmission power. The judgment logic is as follows: preset pollution threshold A typical value is 15%. ≥15% indicates severe pollution, triggering a prompt from the main control unit to remind the user to initiate an avoidance procedure; when If the pollution level is less than 15%, it indicates that the pollution is minor and the current area can continue to be used without any adjustments.

7. The deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander according to claim 1, characterized in that, The device also includes a human-machine interface unit connected to the main control unit, including buttons or a touch screen for manually controlling displacement and setting parameters, a status display screen for displaying the position of the beam expander, the light spot status and the working mode, and an audible and visual alarm module triggered in abnormal situations.

8. The deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander according to claim 1, characterized in that, All components of the laser fixing module and the beam expander translation adjustment module of the device are made of ultra-low gas release and UV protection materials specifically for the deep ultraviolet band, in order to avoid introducing additional contaminants into the optical path.

9. The deep ultraviolet laser interferometer avoidance device based on dynamic adjustment of a beam expander according to any one of claims 1 to 8, characterized in that, The electronically controlled drive module includes an X / Y axis stepper or servo motor, a motor driver, a linear guide and a ball screw transmission mechanism, and a positioning self-locking mechanism; the positioning self-locking mechanism locks the beam expander translation adjustment module after the main control unit issues a stop command to prevent position drift.

10. A method for avoiding deep ultraviolet laser interferometers based on dynamic adjustment of a beam expander, applied to the apparatus of any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Pollution determination: The main control unit receives the signal emitted by the interferometer body due to performance degradation or the pollution signal confirmed by manual verification, and determines that light pollution has occurred in the current laser incident area of ​​the beam expander. S2. Adjustment Start-up: The user starts the contamination avoidance program through the human-machine interaction unit, and the main control unit retrieves the preset or manually input target clean area coordinates; S3. Dynamic translational adjustment: The main control unit controls the electronically controlled drive module to drive the beam expander translational adjustment module to perform pure translation based on the coordinates of the target clean area, so that the laser incident point moves from the contaminated area to the target clean area. During the adjustment process, the laser fixing module remains stationary and the beam expander does not deflect at any angle. S4. Spot Coverage Monitoring: During the adjustment process, the spot coverage monitoring module acquires the spot image after beam expansion in real time and calculates its coverage ratio with the first lens of the interferometer. S5. Position Locking: When the main control unit receives a signal that the coverage ratio is qualified, it immediately controls the electronic control drive module to stop driving and starts the position self-locking mechanism to lock the current position of the beam expander and complete the in-situ avoidance of the contaminated area; S6. Resumption of Operation: The interferometer directly utilizes the laser emitted from the clean area of ​​the beam expander to resume normal detection operation without the need for additional optical path calibration.

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