Excimer laser energy detection and feedback regulation system

Abstract

The invention relates to the technical field of laser control, and discloses an excimer laser energy detection and feedback regulation system, which comprises an energy acquisition module configured to be used for receiving part of light beams of an excimer laser and converting optical signals into analog current signals. For a strong electromagnetic interference (EMI) environment generated by high-voltage discharge of an excimer laser, nanosecond transient pulses are locked as quasi-direct current signals through a peak holding circuit, and the bandwidth requirement is reduced; the optical fiber transmission module is used for realizing electrical full isolation and cutting off common-mode interference; a truncation mean filtering algorithm is introduced at a source end, and discharge peak noise is accurately eliminated. Compared with the traditional technical scheme of directly collecting only depending on a V / F chip and having no MCU digital processing, the measurement error under the severe working condition is reduced to be within + / -3% from + / -8%, and the detection precision and the anti-interference capability are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of laser control technology, specifically to an excimer laser energy detection and feedback adjustment system. Background Technology

[0002] Excimer lasers, with their short wavelength, high power, and narrow linewidth, have irreplaceable application value in fields such as semiconductor lithography, precision medical processing, and material modification. However, the stability of their output energy directly affects processing accuracy and equipment reliability, becoming one of the core bottlenecks restricting their performance.

[0003] The following are the main drawbacks of similar technologies in application: Excimer lasers generate laser light using high-pressure gas discharge (thousands of volts), and their operating environment is accompanied by strong electromagnetic pulse (EMI) interference. Traditional energy detection systems often use direct analog voltage transmission or V / F conversion chips with weak anti-interference capabilities for acquisition. Due to the lack of an effective source-side digital filtering mechanism, the voltage signal output by the peak hold circuit is easily coupled with discharge spike noise, resulting in serious deviations in the energy monitoring values ​​and failing to accurately reflect the energy state of the laser pulse.

[0004] Existing calibration methods are typically based on the ideal assumption that "photodetectors are linear devices," using a simple linear formula (y=kx+b) for calculation. However, in high-energy-density applications, detectors such as silicon photodiodes exhibit significant saturation effects (space charge effects cause sensitivity to decrease with increasing light intensity). If these physical nonlinearities are not effectively corrected, they will lead to lower measured values ​​in the high-energy region, limited dynamic range, and severely impact control accuracy in high-power processing scenarios.

[0005] Existing systems mostly rely on threshold alarms or open-loop monitoring, lacking real-time closed-loop linkage with high-voltage power supplies. Due to energy drift caused by gas aging and thermal lensing effects during laser operation, as well as temperature drift during cold starts, fixed control parameters are difficult to maintain long-term stability. Existing control methods often have lag in response and cannot cope with single-pulse-level energy fluctuations, resulting in persistently high production scrap rates.

[0006] Therefore, developing an energy control system that can isolate interference from the hardware architecture, compensate for sensor nonlinearity from the algorithm, and has rapid adaptive closed-loop capability is of great significance for improving the performance of excimer lasers. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an excimer laser energy detection and feedback adjustment system, which solves the problems mentioned in the background section.

[0008] This invention provides the following technical solution: an excimer laser energy detection and feedback adjustment system, comprising: The energy harvesting module is configured to receive a portion of the beam from the excimer laser and convert the optical signal into an analog current signal. A signal conditioning module, connected to the energy harvesting module, is configured to convert the analog current signal into an analog voltage signal, and includes a peak hold circuit for holding the peak voltage of the laser pulse. The secondary control unit is connected to the signal conditioning module and is configured to perform analog-to-digital conversion to acquire the peak voltage and perform digital filtering to obtain the target voltage value. The fiber optic transmission module includes an electro-optical conversion transmitter and a photoelectric conversion receiver; The main control unit is communicatively connected to the secondary control unit via the optical fiber transmission module; And a high-voltage power supply adjustment module, which is connected to the main control unit and the pump source of the laser; The sub-control unit is configured to convert the target voltage value into a corresponding pulse frequency signal according to a preset mapping relationship, and send it to the main control unit through the optical fiber transmission module; The main control unit is configured to receive the pulse frequency signal, convert it back into energy data, and generate control commands using a PID algorithm to adjust the output voltage of the high-voltage power supply regulating module based on the deviation between the energy data and a preset target energy value.

[0009] Preferably, the preset mapping relationship is a nonlinear binomial relationship, used to compensate for the sensitivity decay of the energy harvesting module under high energy density; The binomial relationship satisfies: f = -A·v^2 - B·v + C; where f is the pulse frequency signal, v is the target voltage value, and A, B, and C are all preset constants greater than zero.

[0010] Preferably, the digital filtering process performed by the sub-control unit employs a truncated mean filtering algorithm, and the specific steps include: Collect N consecutive sets of peak voltage data; Sort the N sets of data according to their numerical values; Remove the largest X% and smallest Y% of the sorted data; The arithmetic mean of the remaining data is calculated as the target voltage value.

[0011] Preferably, N is 100, X and Y are both 40, and the digital filtering process controls the measurement error within ±3%.

[0012] Preferably, the main control unit calculates the energy data based on a polynomial fitting model, wherein the model satisfies: E = a·f^3 + b·f^2 + c·f + d; where E is the real-time pulse energy value, f is the received pulse frequency signal, and a, b, c, d are the fitting coefficients obtained through calibration.

[0013] Preferably, the main control unit is further configured to perform in-run self-calibration: During the laser startup phase, the frequency values ​​of the first M pulses are collected and the average value is calculated as the reference energy frequency. The target setpoint of the polynomial fitting model or PID control is dynamically corrected based on the reference energy frequency.

[0014] Preferably, the signal conditioning module includes a first-stage operational amplifier unit and a peak hold circuit connected thereto: The first-stage operational amplifier unit is configured as a non-inverting amplifier circuit, which includes a feedback resistor network for setting the signal gain; The peak hold circuit uses the unidirectional conduction characteristic of diodes and the storage characteristic of capacitors to lock the pulse peak. Furthermore, the signal conditioning module also includes a reset circuit for discharging and resetting the capacitor after the acquisition is completed.

[0015] The present invention has the following beneficial effects: To address the strong electromagnetic interference (EMI) environment generated by the high-voltage discharge of excimer lasers, a peak hold circuit is used to lock nanosecond-level transient pulses into quasi-DC signals, reducing bandwidth requirements. An optical fiber transmission module is used to achieve full electrical isolation, cutting off common-mode interference. A truncated mean filtering algorithm is introduced at the source end to accurately eliminate discharge spike noise. Compared to traditional solutions that rely solely on direct acquisition by a V / F chip without MCU digital processing, this invention reduces the measurement error under harsh operating conditions from ±8% to within ±3%, significantly improving detection accuracy and anti-interference capability.

[0016] To address the sensitivity degradation (saturation effect) of photodetectors in the high-energy region, this invention artificially stretches the resolution in the high-energy region through binomial nonlinear mapping in the secondary control unit, and performs high-order regression through cubic polynomial fitting in the main control unit. This dual compensation mechanism, with its coordinated front-end and back-end operations, greatly expands the dynamic measurement range of the system, ensuring measurement linearity from weak signals (<5mJ) to the high-energy saturation region (>50mJ).

[0017] Through the "20-pulse self-calibration before startup" mechanism, the main control unit dynamically collects the average frequency as a reference, eliminating zero-point offset caused by device aging and cold start temperature drift. This process is completed automatically during system startup, eliminating the need for frequent production interruptions and manual calibration relying on external standard light sources, as is the case with existing technologies, thus greatly ensuring production continuity.

[0018] Through microsecond-level data acquisition and real-time PID closed-loop control, this system can capture and smooth single-pulse-level energy fluctuations, reducing the laser output energy instability (Sigma) to 1.2%. Compared with traditional threshold alarm systems, it effectively avoids processing defects caused by energy detection lag, reducing the scrap rate by more than 40%. At the same time, stable energy output reduces overload losses, helps extend the lifespan of expensive excimer laser electrodes and gases, and significantly reduces the overall maintenance costs of the equipment throughout its lifecycle. Attached Figure Description

[0019] Figure 1 This is an overall structural block diagram of the excimer laser energy closed-loop control system provided in an embodiment of the present invention.

[0020] Figure 2 This is a circuit diagram of the signal conditioning module in an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram illustrating the algorithm principle of binomial mapping and cubic fitting in an embodiment of the present invention.

[0022] Figure 4 A flowchart of an excimer laser energy closed-loop control method provided in an embodiment of the present invention.

[0023] 10. Excimer laser; 20. Beam splitter; 100. Energy harvesting module; 110. Photodiode; 200. Signal conditioning module; 210. First-stage operational amplifier unit; 211. Feedback resistor; 212. Variable resistor; 220. Peak hold circuit; 221. Diode; 222. Holding capacitor; 230. Reset circuit; 231. Reset transistor; 300. Secondary control unit; 400. Fiber optic transmission module; 410. Electro-optical conversion transmitter; 420. Optical fiber; 430. Photoelectric conversion receiver; 500. Main control unit; 600. High-voltage power supply regulation module. Detailed Implementation

[0024] 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.

[0025] Please see Figure 1 - Figure 4 The excimer laser 10 energy detection and feedback adjustment system includes: The energy harvesting module 100 is configured to receive a portion of the beam from the excimer laser 10 and convert the optical signal into an analog current signal. The signal conditioning module 200, connected to the energy harvesting module 100, is configured to convert analog current signals into analog voltage signals and includes a peak hold circuit 220 for holding the peak voltage of the laser pulse. The secondary control unit 300 is connected to the signal conditioning module 200 and is configured to perform analog-to-digital conversion to acquire the peak voltage and perform digital filtering to obtain the target voltage value. The fiber optic transmission module 400 includes an electro-optical conversion transmitter 410 and a photoelectric conversion receiver 430. The main control unit 500 is communicatively connected to the secondary control unit 300 via the fiber optic transmission module 400; And a high-voltage power supply adjustment module 600, which is connected to the main control unit 500 and the pump source of the laser; The secondary control unit 300 is configured to convert the target voltage value into a corresponding pulse frequency signal according to a preset mapping relationship, and send it to the main control unit 500 through the fiber optic transmission module 400. The main control unit 500 is configured to receive pulse frequency signals, convert them back into energy data, and generate control commands through a PID algorithm to adjust the output voltage of the high-voltage power supply regulating module 600 based on the deviation between the energy data and the preset target energy value.

[0026] In an optional embodiment: the preset mapping relationship is a non-linear binomial relationship, which is used to compensate for the sensitivity decay of the energy harvesting module 100 under high energy density; The binomial relationship satisfies: f = -A·v^2 - B·v + C; where f is the pulse frequency signal, v is the target voltage value, and A, B, and C are all preset constants greater than zero. The coefficients A, B, and C can be adjusted according to different power levels of the laser.

[0027] In an optional embodiment: the digital filtering process performed by the sub-control unit 300 employs a truncated mean filtering algorithm, the specific steps of which include: Collect N consecutive sets of peak voltage data; Sort the N sets of data according to their numerical values; Remove the largest X% and smallest Y% of the sorted data; Calculate the arithmetic mean of the remaining data as the target voltage value.

[0028] In an optional embodiment: N is 100, X and Y are both 40, and digital filtering controls the measurement error to within ±3%.

[0029] In an optional embodiment: the main control unit 500 calculates energy data based on a polynomial fitting model, the model satisfying: E = a·f^3 + b·f^2 + c·f + d; where E is the real-time pulse energy value, f is the received pulse frequency signal, and a, b, c, d are the fitting coefficients obtained through calibration.

[0030] In an optional embodiment: the main control unit 500 is also configured to perform in-run self-calibration: During the laser startup phase, the frequency values ​​of the first M pulses are collected and the average value is calculated as the reference energy frequency. The target setpoint is dynamically adjusted based on the reference energy frequency to modify the polynomial fitting model or PID control.

[0031] In an optional embodiment: the signal conditioning module 200 includes a first-stage operational amplifier unit 210 and a peak hold circuit 220 connected thereto. The first-stage operational amplifier unit 210 is configured as a non-inverting amplifier circuit, which includes a feedback resistor network for setting the signal gain. The secondary peak hold circuit 220 uses the unidirectional conduction characteristic of diode 221 and the storage characteristic of holding capacitor 222 to lock the pulse peak. Furthermore, the signal conditioning module 200 also includes a reset circuit 230, which is used to discharge and reset the holding capacitor 222 after the acquisition is completed. The input terminal of this system is the energy harvesting module 100, which uses a broadband photodiode 110, preferably model S1226-8BQ. This device has a wide spectral response range of 190nm-1100nm, making it suitable for detecting excimer lasers at 193nm / 248nm.

[0032] As another implementation of the energy harvesting module 100, for power densities exceeding... For such applications, thermopile detectors can be selected, although their response speed is slower, they have a higher damage resistance threshold.

[0033] The energy harvesting module 100 is placed to the side of the beam splitter 20 in the optical path of the excimer laser 10, and receives about 1% of the sampled beam.

[0034] The signal conditioning module 200 realizes signal acquisition and is composed of the first-stage operational amplifier unit 210 and the peak hold circuit 220.

[0035] The operational amplifier selected for the signal conditioning module 200 is preferably the TL084IDT four-channel JFET input operational amplifier with high input impedance and low noise.

[0036] The operational amplifier in the signal conditioning module 200 is not limited to the TL084 series. Those skilled in the art can select similar chips with high input impedance characteristics, such as TL074CN, LF347 or OPA4134, according to specific performance requirements.

[0037] The first-stage operational amplifier unit 210 is used for transimpedance amplification and gain setting; The first-stage operational amplifier is configured for either non-inverting or transimpedance amplification. The output of photodiode 110 is connected to the non-inverting input of the operational amplifier. The inverting input of the operational amplifier is grounded or connected to a reference level via a feedback resistor network.

[0038] The feedback resistor network consists of a fixed feedback resistor 211 and a variable resistor 212 connected in series.

[0039] By adjusting the variable resistor 212, the output voltage amplitude of the first-stage operational amplifier can be linearly adjusted to adapt to lasers of different power.

[0040] In one embodiment, the feedback resistor 211 is selected as 10kΩ, and the variable resistor 212 is 0-50kΩ. This resistance range ensures that the photocurrent is within a certain range. Within this range, the op-amp output is in the linear region of 1V-3V, avoiding the signal being overwhelmed by noise due to being too small or saturated due to being too large.

[0041] The applicability of feedback resistor networks is explained by providing the following three lower-level implementation examples for different energy levels.

[0042] Example A: A conventional excimer laser 10 for photolithography with a single-pulse energy of 5mJ-20mJ.

[0043] The feedback resistor 211 is selected as 10kΩ. The holding capacitor 222 is selected as 470pF.

[0044] A 10mJ input corresponds to an output of approximately 1.5V, which is within the optimal linear range of the secondary control unit 300.

[0045] Example B: Single pulse energy <5mJ after long optical path attenuation.

[0046] The feedback resistor 211 is increased to 47kΩ. The holding capacitor 222 is decreased to 100pF.

[0047] according to Increase R to compensate for the decrease in I, maintain the output voltage amplitude, and ensure the signal-to-noise ratio. Decrease the holding capacitor 222 to adapt to the charging speed under weak current and prevent undercharging.

[0048] Example C: Single pulse energy > 50mJ, such as a high-power laser for materials processing.

[0049] The feedback resistor 211 was reduced to 2kΩ.

[0050] High energy generates high current, so reducing R lowers the gain and prevents op-amp output saturation clipping. In this case, it's necessary to use binomial mapping to increase the factor A to 1500 for nonlinear compensation.

[0051] The excimer laser 10 has an extremely narrow laser pulse width, typically... A typical secondary control unit has a sampling rate of 300, such as 1 MSPS, and a sampling period of... It is difficult to capture the peak of the pulse.

[0052] The output of the first-stage op-amp is connected to the non-inverting input of the second-stage op-amp.

[0053] A high-frequency switching diode 221 (model 1N4148) is connected in series at the output of the second-stage op-amp peak hold circuit 220. The cathode of the diode 221 is connected to one end of the holding capacitor 222, and the other end of the holding capacitor 222 is grounded.

[0054] When the laser pulse from the excimer laser 10 arrives, the voltage rises rapidly, and the diode 221 turns on to quickly charge the holding capacitor 222; when the pulse ends, the diode 221 turns off in reverse, and the holding capacitor 222 is in a floating state, locking the peak voltage.

[0055] The preferred capacitance for the 222 capacitor is 470pF. Time constant of charging circuit .

[0056] in The sum of the on-resistance of diode 221 and the output impedance of operational amplifier is approximately .

[0057] but .

[0058] because This indicates that the capacitor voltage can rapidly rise to over 90% of its peak value within the pulse duration, ensuring real-time capture.

[0059] During the holding phase, the time constant of the discharge circuit .

[0060] in The input impedance of the subsequent secondary control unit is typically 300. .

[0061] but .

[0062] Support sub-control unit 300 in Multiple data acquisitions were completed within the timeframe, and voltage drops were negligible.

[0063] The reset circuit 230 uses an NPN transistor reset transistor 231, model 2N3904.

[0064] The collector of the reset transistor 231 is connected to the positive terminal of the holding capacitor 222, the emitter is directly grounded, and the base is connected to the sub-control unit 300.

[0065] After the data acquisition is completed, the secondary control unit 300 sends a high-level pulse to turn on the reset transistor 231, which discharges the charge on the holding capacitor 222 to zero, preparing for the next data acquisition.

[0066] The secondary control unit 300 and the main control unit 500 use STM32F103 and STM32F407 microcontrollers (MCUs), respectively.

[0067] The secondary control unit 300 and the main control unit 500 are not limited to STM series microcontrollers. Those skilled in the art can use DSPs such as the TMS320 series, FPGAs such as the Cyclone series, or other ARM core processors to implement the same data acquisition and algorithm logic according to the computing power requirements.

[0068] The electro-optical conversion transmitter 410 uses HFBR-1521Z, the photoelectric conversion receiver 430 uses HFBR-2521Z, and the transmission medium is an ST interface optical fiber 420.

[0069] The electrical connection between the high-voltage discharge circuit and the main control board is physically severed, eliminating transient common-mode interference of up to several kilovolts and preventing the main control board from resetting or crashing.

[0070] Example 2: This example details the core algorithms and experimental data running in the sub-control unit 300 and the main control unit 500.

[0071] Truncated mean filtering algorithm Step A: For the same pulse voltage locked by the peak holding circuit 220, start the sub-control unit 300 to perform high-speed conversion N=100 times consecutively.

[0072] Step B: Sort the sample set in ascending order using the quicksort algorithm.

[0073] Step C: Remove the top 40 data points (X=40%) with the largest values ​​in the sequence to eliminate the high-frequency spike noise superimposed during the discharge. The last 40 data points, Y=40%, with the smallest value in the sequence are removed to eliminate potential effects from slight capacitor leakage or instability during the initial signal establishment phase.

[0074] Step D: Calculate the arithmetic mean of the remaining 20%, i.e., the middle 20 data points, and use this as the final effective voltage value of the pulse. .

[0075] When the excimer laser 10 is operating, the instant the high-voltage switch is turned on, it generates strong electromagnetic radiation, which couples into the acquisition circuit and manifests as random, high-amplitude spike noise. This noise is typically short-lived, but statistically located in the extreme value region. Ordinary mean filtering cannot eliminate these outliers. This embodiment, through a bidirectional rejection rate of up to 40%, statistically forces the removal of all possible high-value interference spikes and low-value circuit instability, retaining only the center value with the highest probability density, thereby achieving anti-interference.

[0076] As shown in the table below, under 500Hz high-voltage discharge interference, the volatility of ordinary mean filtering is ±8.5%, while the truncated mean filtering in this embodiment reduces the volatility to ±2.3%.

[0077] Interference environment Traditional mean filtering error The truncation mean error in this embodiment Improved results Static and interference-free ±1.2% ±0.8% Slight improvement 500Hz high voltage discharge ±8.5% ±2.3% Significant improvement strong magnetic field interference ±12.4% ±2.9% Significant improvement The photodiode 110 exhibits excellent linearity under low light intensity, but under high light intensity and high energy density, due to the space charge effect, the photocurrent no longer increases linearly with light intensity, but instead exhibits a "soft saturation" characteristic, resulting in sensitivity decay. To compensate for this physical nonlinearity at the source end, the sub-control unit 300 modulates the acquired voltage... Converted to pulse frequency signal In this case, instead of using a linear formula, a binomial equation with a binomial nonlinear mapping is used:

[0078] set up .

[0079] when When the energy is small, the low energy region, The effect of the term is minimal and approximately linear.

[0080] when Larger high-energy regions Negative values ​​of the term make the pulse frequency signal The downward slope becomes larger.

[0081] In the high-energy region, a change in unit voltage will cause a greater frequency change, thus "stretching" the resolution of the high-energy region and offsetting the "compression" effect of the probe.

[0082] The main control unit 500 (STM32F407) receives the pulse frequency signal. Then, the energy is restored through the inverse operation model. Because the front end uses binomial mapping and the entire optoelectronic link exhibits high-order nonlinearity, this embodiment employs a cubic polynomial model:

[0083] The coefficients of this model were obtained through factory calibration. In a typical set of data:

[0084]

[0085]

[0086]

[0087] The model has a fitting residual of less than 0.08 mJ across the full dynamic range of 5 mJ to 50 mJ, which is better than the linear fitting residual of about 1.5 mJ, ensuring the input accuracy of subsequent PID control.

[0088] A closed-loop energy control method for an excimer laser 10 includes the following steps: Step S1: The laser pulse signal is captured by the energy harvesting module 100 and its peak voltage is maintained by the peak holding circuit 220; Step S2: Collect multiple sets of peak voltage data through the secondary control unit 300, remove high and low values ​​with a preset ratio, and calculate the truncated mean. Step S3: Map the truncated mean value to a pulse frequency signal and send it to the main control unit 500 through the fiber optic transmission module 400. The mapping adopts the binomial equation f=-A·v^2-B·v+C to compensate for the nonlinear response of the sensor. Step S4: The frequency signal is restored to the energy value in the main control unit 500, and the high voltage power supply voltage is adjusted using the PID algorithm to form a closed-loop control.

[0089] Specifically, including Step 1: System startup and initialization. After the system is powered on, the main control unit 500 first completes the initialization: a. Configure peripherals such as the secondary control unit 300, timer, serial port, and pulse frequency signal acquisition.

[0090] b. Load the preset high-voltage power supply voltage parameters, such as the preset value of 1500V, which can be adjusted via the host computer according to process requirements.

[0091] c. Self-calibration: During the first M=20 pulses of laser ignition, the main control unit 500 does not perform PID adjustment, but instead records the average frequency of these 20 pulses. . use Update the target setpoint of the PID control to eliminate the temperature drift effect during cold start.

[0092] Step 2: Laser Pulse Detection and Signal Acquisition a. Laser output: The excimer laser 10 generates short-wavelength, high-power laser pulses.

[0093] b. Photoelectric conversion: Photodiode 110 converts light pulses into weak current signals.

[0094] c. Signal conditioning: The first-stage op-amp performs pre-amplification; the second-stage op-amp peak hold circuit 220 captures and locks the pulse peak voltage.

[0095] d. Signal acquisition: After the secondary control unit 300 detects the voltage threshold trigger, it immediately starts to acquire the conditioned voltage signal at high speed 100 times.

[0096] Step 3: Digital Filtering and Frequency Conversion a. Digital filtering: The sub-control unit 300 sorts 100 sets of data, removes the first and last 40% of the data, and calculates the arithmetic mean of the remaining 20 data to obtain the effective voltage value. .

[0097] b. Frequency mapping: Mapping the filtered voltage value... Substituting into the binomial equation This generates a pulse frequency signal.

[0098] Step 4: Fiber optic transmission and signal decoupling a. Electro-optical conversion: The pulse frequency signal output by the secondary control unit 300 is converted into optical pulses by the HFBR-1521Z.

[0099] b. Fiber optic transmission: The signal is transmitted to the main control terminal through fiber optic cable 420, achieving electrical isolation.

[0100] c. Signal decomposition: The main control unit 500 receives optical signals and analyzes pulse frequency signals.

[0101] Step 5: Energy Calculation and Closed-Loop Control a. Energy Calculation: The main control unit 500 will calculate the real-time frequency. Substituting into the cubic polynomial Calculate the precise energy value .

[0102] b. Error calculation: .

[0103] c. PID control: using formulas in Calculate the adjustment amount.

[0104] d. High voltage output: The main control unit 500 sends adjustment commands to the high voltage power supply adjustment module 600 via optical fiber 420.

[0105] e. Scope of application: The high-voltage power supply regulation module 600 in this embodiment is not limited to 0-1.5KV, and its voltage range can be any high-voltage excitation power supply higher than the mains voltage.

[0106] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0107] 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. An excimer laser energy detection and feedback adjustment system, characterized in that, include: An energy harvesting module (100) is configured to receive a portion of the beam from an excimer laser (10) and convert the optical signal into an analog current signal; The signal conditioning module (200), connected to the energy harvesting module (100), is configured to convert the analog current signal into an analog voltage signal, and includes a peak hold circuit (220) for holding the peak voltage of the laser pulse; The sub-control unit (300) is connected to the signal conditioning module (200) and is configured to perform analog-to-digital conversion to acquire the peak voltage and perform digital filtering to obtain the target voltage value. The fiber optic transmission module (400) includes an electro-optical conversion transmitter (410) and an opto-optical conversion receiver (430). The main control unit (500) is communicatively connected to the secondary control unit (300) through the optical fiber transmission module (400); And a high-voltage power supply adjustment module (600), which is connected to the main control unit (500) and the pump source of the laser; The sub-control unit (300) is configured to convert the target voltage value into a corresponding pulse frequency signal according to a preset mapping relationship, and send it to the main control unit (500) through the optical fiber transmission module (400). The main control unit (500) is configured to receive the pulse frequency signal, restore it to energy data, and generate control commands through a PID algorithm to adjust the output voltage of the high-voltage power supply regulating module (600) based on the deviation between the energy data and the preset target energy value.

2. The excimer laser energy detection and feedback adjustment system according to claim 1, characterized in that, The preset mapping relationship is a nonlinear binomial relationship, used to compensate for the sensitivity decay of the energy harvesting module (100) under high energy density; The binomial relationship satisfies: f = -A·v^2 - B·v + C; where f is the pulse frequency signal, v is the target voltage value, and A, B, and C are all preset constants greater than zero.

3. The excimer laser energy detection and feedback adjustment system according to claim 1, characterized in that, The digital filtering process performed by the sub-control unit (300) adopts a truncated mean filtering algorithm, and the specific steps include: Collect N consecutive sets of peak voltage data; Sort the N sets of data according to their numerical values; Remove the largest X% and smallest Y% of the sorted data; The arithmetic mean of the remaining data is calculated as the target voltage value.

4. The excimer laser energy detection and feedback adjustment system according to claim 3, characterized in that, The N is 100, the X and Y are both 40, and the digital filtering process controls the measurement error to within ±3%.

5. The excimer laser energy detection and feedback adjustment system according to claim 1, characterized in that, The main control unit (500) calculates the energy data based on a polynomial fitting model, the model satisfying: E = a·f^3 + b·f^2 + c·f + d; where E is the real-time pulse energy value, f is the received pulse frequency signal, and a, b, c, d are the fitting coefficients obtained through calibration.

6. The excimer laser energy detection and feedback adjustment system according to claim 1, characterized in that, The main control unit (500) is also configured to perform in-run self-calibration: During the laser startup phase, the frequency values ​​of the first M pulses are collected and the average value is calculated as the reference energy frequency. The target setpoint of the dynamic correction polynomial fitting model or PID control is based on the reference energy frequency.

7. The excimer laser energy detection and feedback adjustment system according to claim 1, characterized in that, The signal conditioning module (200) includes a first-stage operational amplifier unit (210) and a peak hold circuit (220) connected thereto: The first stage operational amplifier unit (210) is configured as a non-inverting amplifier circuit, including a feedback resistor network for setting the signal gain; The peak holding circuit (220) locks the pulse peak value by utilizing the unidirectional conduction characteristic of the diode (221) and the storage characteristic of the holding capacitor (222); Furthermore, the signal conditioning module (200) also includes a reset circuit (230) for discharging and resetting the holding capacitor (222) after the acquisition is completed.

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