Rapid peak-finding method and method and device for rapidly measuring laser wavelength

Abstract

A rapid peak-finding method and a method and device for rapidly measuring laser wavelength. The rapid peak-finding method comprises: pre-arranging an energy detector group on the focal plane where the laser to be measured is to form multi-level interference fringes. The energy detector group includes M closely arranged energy detectors, M ≥ 2, and the detection coverage range of the energy detector group is at least equal to the distance between two adjacent levels of interference fringes. When the laser to be measured forms actual interference fringes on the focal plane, the target peak-finding area is determined based on the high and low distribution of the detection voltages of the M energy detectors. The target peak-finding area is the peak-finding area corresponding to the position of a specific energy detector among the M energy detectors. The effective peak position of the actual interference fringes is searched within the target peak-finding area. Rapid prejudgment of the peak area of ​​the interference fringes is achieved, and real-time, high-speed measurement of the wavelength is achieved, which is beneficial to improving the wavelength stability of the laser during operation and helps to improve the output spectrum stability of the excimer laser in the field of lithography.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of laser spectrum measurement, and relates to a rapid peak-finding method and a method and device for rapidly measuring laser wavelength, in particular to a rapid peak-finding method, a method for rapidly measuring laser wavelength, and a device for rapidly measuring laser wavelength that can be used for laser wavelength measurement of excimer lasers in the field of photolithography. Background Art

[0002] An excimer laser is a pulsed gas laser with a wavelength in the ultraviolet band. Its working substance is composed of an inert gas and a halogen element. In its ground state, it is a mixture of two atomic gases. When excited to a high energy level by a short pulse of current, it forms a compound. Each molecule of the compound consists of one atom from each gas, forming a quasi-molecular state. When electrons transition from a high energy level to a low energy level, ultraviolet laser light is emitted.

[0003] During laser research and development, it's often necessary to control laser spectra, such as wavelength and linewidth, to meet diverse application requirements. For example, when used in lithography, slight shifts in the excimer laser's center wavelength can cause defocusing in the system. Therefore, controlling the stability of the excimer laser's center wavelength is crucial. Especially when operating at high frequencies (such as 4kHz and 6kHz), achieving fast, real-time wavelength measurement is crucial for improving wavelength stability.

[0004] Improving the output spectrum stability of excimer lasers, especially the stability of the central wavelength, is of great significance for the development of high-performance excimer lasers and improving the performance of microelectronic lithography processes.

[0005] However, in the prior art, the peak search time is long when measuring the laser wavelength, and real-time measurement of the laser wavelength cannot be achieved, thereby limiting the control of the wavelength stability. Summary of the Invention

[0006] (1) Technical issues to be resolved

[0007] The present disclosure provides a method and device for rapid peak-finding and rapid laser wavelength measurement, which can improve the speed of wavelength measurement and realize real-time measurement of wavelength data, which is conducive to accelerating the frequency of wavelength adjustment and improving the wavelength stability of the laser at a high repetition rate, so as to at least partially solve the problem in the prior art that the laser wavelength measurement speed is slow due to the long peak-finding time of the laser wavelength and the real-time measurement of the laser wavelength cannot be realized.

[0008] (2) Technical solution

[0009] The first aspect of the present disclosure provides a fast peak-finding method for laser wavelength measurement. The above-mentioned fast peak-finding method includes: arranging an energy detector group in advance on the focal plane where the laser to be measured is to form multi-level interference fringes, the energy detector group includes M energy detectors arranged closely, M≥2, and the detection coverage range of the energy detector group is at least equal to the distance between two adjacent levels of interference fringes. The above-mentioned fast peak-finding method also includes: when the laser to be measured forms actual interference fringes on the focal plane, determining the target peak-finding area according to the high and low distribution of the detection voltages of the M energy detectors, the target peak-finding area is the peak-finding area corresponding to the position of a specific energy detector among the M energy detectors. The above-mentioned fast peak-finding method also includes: finding the effective peak position of the actual interference fringes in the target peak-finding area.

[0010] A second aspect of the present disclosure provides a method for rapidly measuring laser wavelength. The method includes: arranging a FP etalon, a lens, and a beam splitter in a measurement optical path. The laser to be measured sequentially passes through the FP etalon, the lens, and the beam splitter to form two outgoing beams. An energy detector group is arranged on the focal plane of one outgoing beam, and an optical imaging element is arranged on the focal plane of the other outgoing beam. The energy detector group includes M closely spaced energy detectors, where M ≥ 2, and the detection coverage of the energy detector group is at least equal to the distance between two adjacent levels of interference fringes. The method also includes: when the laser to be measured passes through the FP etalon, the lens, and the beam splitter to form actual interference fringes on the optical imaging element, determining a target peak-seeking region based on the high and low distribution of detection voltages of the M energy detectors. The target peak-seeking region is the peak-seeking region corresponding to the position of a specific energy detector among the M energy detectors. The method also includes: finding the effective peak position of the actual interference fringes within the target peak-seeking region of the optical imaging element. The method also includes: determining the interference fringes radius based on the effective peak position of the actual interference fringes. The method for rapidly measuring laser wavelength further includes: determining the wavelength of the laser to be measured according to the spacing of the FP etalon, the focal length of the lens, and the radius of the interference fringe.

[0011] The third aspect of the present disclosure provides a fast peak-finding device for laser wavelength measurement. The above-mentioned fast peak-finding device includes: an energy detector group, a peak-finding area determination module and a peak-finding module. The energy detector group is arranged on the focal plane where the laser to be measured is to form multi-level interference fringes. The energy detector group includes M energy detectors arranged closely, M≥2, and the detection coverage range of the energy detector group is at least equal to the distance between two adjacent levels of interference fringes. The peak-finding area determination module is used to determine the target peak-finding area according to the high and low distribution of the detection voltages of the M energy detectors when the laser to be measured forms actual interference fringes on the focal plane. The target peak-finding area is the peak-finding area corresponding to the position of a specific energy detector among the M energy detectors. The peak-finding module is used to find the effective peak position of the actual interference fringes in the target peak-finding area.

[0012] A fourth aspect of the present disclosure provides a device for rapidly measuring laser wavelength. The device comprises: a FP etalon, a lens, a beam splitter, an energy detector group, an optical imaging element, a peak-seeking region determination module, a peak-seeking module, an interference fringe radius determination module, and a wavelength determination module, arranged in the measurement optical path of the laser to be measured. The laser to be measured passes through the FP etalon, the lens, and the beam splitter in sequence, forming two outgoing beams. The energy detector group is arranged on the focal plane of one outgoing beam, and the optical imaging element is arranged on the focal plane of the other outgoing beam. The energy detector group comprises M closely spaced energy detectors, where M ≥ 2, and the detection coverage of the energy detector group is at least equal to the distance between two adjacent interference fringes. The peak-seeking region determination module is configured to determine a target peak-seeking region based on the high and low distribution of detection voltages of the M energy detectors when the laser to be measured forms actual interference fringes on the optical imaging element after passing through the FP etalon, the lens, and the beam splitter. The target peak-seeking region is the peak-seeking region corresponding to the position of a specific energy detector among the M energy detectors. The peak-finding module is used to locate the effective peak position of the actual interference fringes within the target peak-finding region of the optical imaging element. The interference fringe radius determination module is used to determine the interference fringe radius based on the effective peak position of the actual interference fringes. The wavelength determination module is used to determine the wavelength of the laser to be measured based on the spacing of the FP etalon, the focal length of the lens, and the interference fringe radius.

[0013] (3) Beneficial effects

[0014] It can be seen from the above technical solutions that the rapid peak finding method and the rapid laser wavelength measurement method and device provided by the present disclosure have the following beneficial effects:

[0015] When the laser wavelength changes, it will cause the interference fringe peak to move in the focal plane. By setting up an energy detector group, the detection voltages of the energy detectors at positions corresponding to different areas of the interference fringes in the energy detector group will change accordingly with the position of the interference fringe peak. Therefore, the peak-seeking area corresponding to the position of a specific energy detector is determined as the target peak-seeking area based on the relative highs and lows of the detection voltages of multiple energy detectors in the energy detector group. This achieves rapid prediction of the interference fringe peak area, shortens the wavelength calculation time, and realizes real-time, high-speed measurement of the wavelength, which is beneficial to improving the wavelength stability of the laser during operation. It can be applied to the wavelength measurement of excimer lasers to improve the output spectrum stability of excimer lasers. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 4 is a flow chart of a fast peak-finding method for laser wavelength measurement according to an embodiment of the present disclosure.

[0017] Figure 2 FIG. 4 is a component layout of a device for rapidly measuring laser wavelength according to an embodiment of the present disclosure.

[0018] Figure 3 Schematic diagram of the distribution of energy detector groups arranged in the first-order interference fringe active area according to an embodiment of the present disclosure.

[0019] Figure 4 Schematic diagram of the relationship between the voltage of each energy detector in the energy detector group, the laser wavelength and the peak-seeking area according to one embodiment of the present disclosure.

[0020] Figure 5 Schematic diagram of the distribution of multiple energy detector groups arranged in the second-order interference fringe active area according to another embodiment of the present disclosure.

[0021] Figure 6 The figure is a flow chart of a method for rapidly measuring laser wavelength according to an embodiment of the present disclosure.

[0022] Figure 7 4 is a structural block diagram of a fast peak-finding device for laser wavelength measurement according to an embodiment of the present disclosure.

[0023] Figure 8 4 is a structural block diagram of a device for rapidly measuring laser wavelength according to an embodiment of the present disclosure.

[0024]

Explanation of symbols

[0025] 11-FP etalon; 12-lens;

[0026] 13-beam splitting element; 14-optical imaging element;

[0027] 15-Energy detector group;

[0028] 151, 152-energy detector;

[0029] 3- Rapid peak-finding device for laser wavelength measurement;

[0030] 31-Energy detector group; 32-Peak search area determination module;

[0031] 33-peak search module;

[0032] 4-A device for quickly measuring laser wavelength;

[0033] 41-FP etalon; 42-lens;

[0034] 43-beam splitting element; 44-optical imaging element;

[0035] 45-energy detector group; 46-peak search area determination module;

[0036] 47-peak finding module; 48-interference fringe radius determination module;

[0037] 49-Wavelength determination module. DETAILED DESCRIPTION

[0038] In related technologies, some studies have focused on shortening the wavelength adjustment time and improving wavelength stability from the perspective of structural design. Some studies have proposed a wavelength stability control device, in which the wavelength measurement system is used to monitor the laser output wavelength output by the resonant cavity, and the control system processes the wavelength measurement data to perform feedback control on the precision turntable. It can be seen that in order to improve the stability of the laser output wavelength, in addition to fast response mechanisms such as motors, high-speed wavelength measurement and control methods are also required. Especially when the laser operates at high frequency / repetition rate (such as 4kHz, 6kHz, etc.), high-speed wavelength measurement is of great significance for improving wavelength stability.

[0039] The embodiments of the present disclosure provide a method and apparatus for rapid peak-finding and rapid measurement of laser wavelength. The method determines the peak-finding area corresponding to the position of a specific energy detector as the target peak-finding area based on the relative highs and lows of the detection voltages of multiple energy detectors in an energy detector group. This enables rapid prediction of the peak area of ​​the interference fringe, shortens the time for wavelength calculation, and realizes real-time, high-speed measurement of the wavelength, which is beneficial to improving the wavelength stability of the laser during operation. The method can be applied to the wavelength measurement of an excimer laser to improve the output spectrum stability of the excimer laser.

[0040] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0041] A first exemplary embodiment of the present disclosure provides a fast peak-finding method for laser wavelength measurement.

[0042] Figure 1 4 is a flow chart of a fast peak-finding method for laser wavelength measurement according to an embodiment of the present disclosure.

[0043] Reference Figure 1 As shown, the fast peak-finding method for laser wavelength measurement disclosed in the present invention includes the following operations: S11, S12 and S13.

[0044] In operation S11, an energy detector group is pre-arranged on the focal plane where the laser to be measured is to form multi-level interference fringes. The energy detector group includes M energy detectors arranged closely, M≥2, and the detection coverage range of the energy detector group is at least equal to the distance between two adjacent interference fringes.

[0045] In operation S12, when the laser to be measured forms actual interference fringes on the focal plane, a target peak-seeking area is determined according to the high and low distribution of the detection voltages of the M energy detectors. The target peak-seeking area is the peak-seeking area corresponding to the position of a specific energy detector among the M energy detectors.

[0046] In operation S13 , an effective peak position of the actual interference fringe is found in the target peak-finding region.

[0047] Figure 2 FIG. 4 is a component layout of a device for rapidly measuring laser wavelength according to an embodiment of the present disclosure. Figure 3 Schematic diagram of the distribution of energy detector groups arranged in the first-order interference fringe active area according to an embodiment of the present disclosure. Figure 4 Schematic diagram of the relationship between the voltage of each energy detector in the energy detector group, the laser wavelength and the peak-seeking area according to one embodiment of the present disclosure.

[0048] The following combination Figures 2 to 4 To describe the principle of achieving rapid peak finding.

[0049] In the embodiments of the present disclosure, referring to Figure 2 and Figure 3 As shown, an energy detector group 15 is arranged on the focal plane where the laser to be measured is to form multi-level interference fringes. The energy detector group 15 includes M energy detectors that are closely arranged. Figure 2 Two energy detectors are used as an example, described as energy detector 151 and energy detector 152. The detection coverage B of the energy detector group 15 is at least equal to the distance L between two adjacent interference fringes. The purpose of closely arranging the M energy detectors in the energy detector group 15 is to ensure that the detection coverage of the energy detector group 15 is continuous.

[0050] Reference Figure 3 As shown, the energy detectors 151 and 152 in the energy detector group 15 each have their own peak-finding regions corresponding to their respective positions. The peak-finding region corresponding to the position of the energy detector 151 is described as peak-finding region A1, and the peak-finding region corresponding to the position of the energy detector 152 is described as peak-finding region A2. The range L1 covered by the peak-finding region A1 on the focal plane is L1, and the range L2 covered by the peak-finding region A2 on the focal plane is L2.

[0051] Reference Figure 4 As shown, taking the example of the detection coverage range B of the energy detector group 15 being equal to the distance L between two adjacent levels of interference fringes, the detection coverage range B may also be greater than the distance L between two adjacent levels of interference fringes. In this embodiment, the energy detectors 151 and 152 each cover an area L / 2. When the wavelength changes, the peak of the interference fringes shifts, and the voltage values ​​measured by the energy detectors 151 and 152 change accordingly. By collecting the detection voltage value U1 of the energy detector 151 and the detection voltage value U2 of the energy detector 152 and comparing the detection voltage values ​​of the two detectors, the target peak-seeking area where the effective peak is located can be determined.

[0052] Specifically, if Figure 4 As shown, when U1>U2, the peak-seeking area is area A1; when U1=U2, the peak-seeking area is area A1 or A2; when U1<U2, the peak-seeking area is area A2.

[0053] When U1 is close to U2, the effective peak appears at the connection between the energy detector 151 and the energy detector 152. In order to avoid incomplete peaks, in the peak-seeking areas corresponding to the positions of the M energy detectors, there is an overlapping area between two adjacent peak-seeking areas. For example, in this embodiment, there is an overlapping area between the peak-seeking area A1 and the peak-seeking area A2. Accordingly, the range L1 covered by the peak-seeking area A1 in the focal plane and the range L2 covered by the peak-seeking area A2 in the focal plane satisfy the following expressions: L1>L / 2, L2>L / 2, as shown in FIG. Figure 3 shown.

[0054] The above description takes the energy detector group 15 including two energy detectors as an example, and the same is applicable to the case of multiple energy detector groups.

[0055] Based on the above, it can be seen that after the laser light to be measured of the wavelength to be measured is actually incident, the laser light to be measured forms actual interference fringes in the focal plane, and the target peak-seeking area is determined based on the high and low distribution of the detection voltages of the M energy detectors. The target peak-seeking area is the peak-seeking area corresponding to the position of a specific energy detector among the M energy detectors. The effective peak position of the actual interference fringes can then be found within the target peak-seeking area. Since the position corresponding to one of the energy detectors is determined as the target peak-seeking area based on the relative high and low detection voltages of the energy detectors, rapid locking of the peak-seeking area is achieved. In this embodiment, the peak-seeking area corresponding to the position of the energy detector with the highest detection voltage among the M energy detectors is the target peak-seeking area.

[0056] For the sake of convenience of description, the energy detector with the highest detection voltage among the M energy detectors is described as a specific energy detector. In order to avoid incomplete peaks, the detection coverage range of the specific energy detector and the target peak-seeking area satisfy the following relationship: the target peak-seeking area covers and is larger than the detection coverage range of the specific energy detector.

[0057] Figure 5 Schematic diagram of the distribution of energy detector groups arranged in the second-order interference fringe active area according to another embodiment of the present disclosure.

[0058] According to an embodiment of the present disclosure, the M energy detectors in the energy detector group are arranged in an interference fringe active area of ​​one level, which can be the highest level, the second highest level or other levels. For example, if n represents the highest level, the second highest level can be represented as n-1, and the M energy detectors can be arranged in the interference fringe active area of ​​any level.

[0059] In the present disclosure, the sequence number of any bright fringe level is represented by m, and the value of m is 1, 2, ..., n-1, n. Figure 3 In the figure, the energy detector group is arranged in the interference fringe active area of ​​the highest order n as an example. Figure 5 In the figure, the energy detector group is arranged in the interference fringe active area of ​​the next higher order n-1 as an example.

[0060] The interference fringe active area of ​​the above order is the position interval of the interference fringes of the order corresponding to all wavelengths in the wavelength measurement range. For example, the wavelength measurement range of the fast peak search method is λ a ~λ b ,by Figure 3 As an example, the wavelength λ a Interference fringe waveform and wavelength λ after laser incidence b The interference fringe waveform after the laser is incident, then the interference fringe activity area of ​​a certain order m is the wavelength measurement range λ a ~λ bThe position interval of the interference fringes of the order m corresponding to all wavelengths within, the value of m is 1, 2, ..., n-1, n, Figure 3 The value of m is equal to the highest level n.

[0061] like Figure 3 As shown, an energy detector group 15 is arranged in the interference fringe active area of ​​the highest order n near the center of the field of view. The preset different wavelength measurement ranges can cover multiple different wavelengths. The spacing between the peaks (bright lines) of adjacent orders in the multi-order interference fringes corresponding to different wavelengths is different. Therefore, as the wavelength changes, the position of the peak will move. Figure 3 In the example, the waveform diagram of interference fringes corresponding to two different wavelengths is used. Since the peak positions of these two different wavelengths at the same order are different, in order to quickly measure different wavelengths, the energy detector group is arranged in the range of the interference fringes of multiple different wavelengths at the same order in the wavelength measurement range. This can be described as: the energy detector group is arranged in the interference fringe active area of ​​1 order. For example, in this embodiment, the energy detector group 15 corresponds to two different wavelengths λ a and λ b The range interval of the highest order n interference fringe activity, that is, the detection coverage range B of the energy detector group 15 covers two different wavelengths λ at the same time a and λ b The highest order interference fringes.

[0062] Similarly, in Figure 5 In the example, the value of m is equal to the constant n-1 corresponding to the next higher order. Figure 5 The two energy detectors 151 and 152 in the energy detector group 15 are respectively arranged in the interference fringe active area of ​​the next higher order n-1. Figure 5 The detection coverage range B of the energy detector 151 and the energy detector 152 in the medium energy detector group 15 covers two different wavelengths λ at the same time a and λ b The second-order interference fringes.

[0063] In summary, this embodiment proposes a fast peak-finding method for laser wavelength measurement. When the laser wavelength changes, it will cause the interference fringe peak to move in the focal plane. By setting up an energy detector group, the detection voltages of the energy detectors at positions corresponding to different areas of the interference fringes in the energy detector group will change accordingly with the position of the interference fringe peak. Therefore, the peak-finding area corresponding to the position of a specific energy detector is determined as the target peak-finding area based on the relative highs and lows of the detection voltages of multiple energy detectors in the energy detector group, thereby achieving fast prediction of the interference fringe peak area.

[0064] Based on the same technical concept, a second exemplary embodiment of the present disclosure provides a method for quickly measuring laser wavelength.

[0065] Figure 6 The figure is a flow chart of a method for rapidly measuring laser wavelength according to an embodiment of the present disclosure.

[0066] Reference Figure 6 As shown, the method for rapidly measuring laser wavelength in this embodiment includes the following operations: S21, S22, S23, S24 and S25.

[0067] In operation S21, an FP etalon, a lens, and a beam splitter are arranged on the measurement optical path. The laser to be measured passes through the FP etalon, the lens, and the beam splitter in sequence to form two outgoing light paths. An energy detector group is arranged on the focal plane of one outgoing light path, and an optical imaging element is arranged on the focal plane of the other outgoing light path.

[0068] In operation S22, when the laser to be measured passes through the FP etalon, lens and beam splitting element to form actual interference fringes in the optical imaging element, the target peak-seeking area is determined based on the high and low distribution of the detection voltages of the M energy detectors. The target peak-seeking area is the peak-seeking area corresponding to the position of a specific energy detector among the M energy detectors.

[0069] In operation S23 , an effective peak position of the actual interference fringe is found in a target peak-finding region of the optical imaging element.

[0070] In operation S24, the interference fringe radius is determined according to the effective peak position of the actual interference fringe.

[0071] In operation S25 , the wavelength of the laser to be measured is determined according to the pitch of the FP etalon, the focal length of the lens, and the interference fringe radius.

[0072] Reference Figure 2 As shown, an FP etalon 11, a lens 12, and a beam splitter 13 are arranged on the measurement optical path. The laser to be measured passes through the FP etalon 11, the lens 12, and the beam splitter 13 in sequence to form two outgoing light paths. An energy detector group 15 is arranged on the focal plane of one outgoing light path, and an optical imaging element 14 is arranged on the focal plane of the other outgoing light path.

[0073] The energy detector group 15 includes M closely arranged energy detectors, M≥2, and the detection coverage of the energy detector group is at least equal to the distance between two adjacent interference fringes. The relevant description of the energy detector group can be referred to the first embodiment and will not be repeated here.

[0074] In this embodiment, the interference fringes are focused on two focal planes with different spatial positions through a beam splitting element, imaging is performed in one of the focal planes, and the target peak-seeking area is quickly determined based on the energy detector group in the other focal plane. Then, rapid peak seeking can be achieved based on the target peak-seeking area in the imaging plane to obtain the effective peak position on one side or both sides. When the effective peak position on one side is obtained, the effective peak position on the other side can be found in the symmetrical target peak-seeking area on the other side that is symmetrically distributed in the target peak-seeking area based on the symmetry of the interference fringes. The interference fringe radius can be obtained based on the effective peak positions on both sides, and the wavelength of the laser to be measured can be determined based on the spacing of the FP standard device, the focal length of the lens and the interference fringe radius.

[0075] In this embodiment, the energy detector group 15 is located on the reflected light path of the beam splitting element 13, and the optical imaging element 14 is located on the transmitted light path of the beam splitting element 13 as an example. In other embodiments, the order of the two can be exchanged, that is, the energy detector group 15 can be located on the transmitted light path of the beam splitting element 13, and the optical imaging element 14 can be located on the reflected light path of the beam splitting element 13.

[0076] According to an embodiment of the present disclosure, the specific energy detector is an energy detector with the highest detection voltage among the M energy detectors, and the target peak-seeking area covers and is larger than the detection coverage range of the specific energy detector.

[0077] According to an embodiment of the present disclosure, the optical imaging element is a linear array CCD, and the beam splitting element 13 is a beam splitter.

[0078] According to an embodiment of the present disclosure, the M energy detectors in the above-mentioned energy detector group are arranged in an interference fringe active area of ​​one order, wherein the interference fringe active area of ​​the above-mentioned order is the position interval of the interference fringes of the order corresponding to all wavelengths within the wavelength measurement range.

[0079] According to an embodiment of the present disclosure, the wavelength of the laser to be measured is determined to satisfy the following expression based on the spacing of the FP etalon, the focal length of the lens, and the interference fringe radius:

[0080]

[0081] Where, λ is the wavelength of the laser to be measured; d is the distance between the two glass plates in the FP etalon; f is the focal length of the lens; R m Indicates the radius of the mth level bright fringe, R m The size of is determined by the number of pixels between two symmetrical effective peak positions of the same level of bright fringe in the optical imaging unit and the size of a single pixel; k represents a constant associated with the level m of the bright fringe corresponding to the effective peak position. Figure 3 In the example, the value of m is equal to the highest order n, R m The corresponding expression is Rn ;exist Figure 5 The value of m is equal to the constant n-1 corresponding to the next higher order, R m The corresponding expression is R n-1 .

[0082] This embodiment provides a method for rapidly measuring laser wavelength. The peak-seeking area corresponding to the position of a specific energy detector is determined as a target peak-seeking area based on the relative highs and lows of the detection voltages of multiple energy detectors in an energy detector group. This method enables rapid prediction of the peak area of ​​the interference fringe, shortens the wavelength calculation time, and realizes real-time, high-speed measurement of the wavelength. This method is beneficial for improving the wavelength stability of the laser during operation and can be applied to the wavelength measurement of an excimer laser to improve the output spectrum stability of the excimer laser.

[0083] A third exemplary embodiment of the present disclosure provides a fast peak-finding device for laser wavelength measurement.

[0084] Figure 7 4 is a structural block diagram of a fast peak-finding device for laser wavelength measurement according to an embodiment of the present disclosure.

[0085] Reference Figure 7 As shown, the rapid peak-finding device 3 includes: an energy detector group 31 , a peak-finding region determination module 32 and a peak-finding module 33 . Figure 7 The connection relationship between the various parts is indicated by connecting lines, and the connection relationship is an electrical connection relationship and / or a communication connection relationship.

[0086] The energy detector group 31 is arranged on the focal plane where the laser to be measured is to form multi-level interference fringes. The energy detector group 31 includes M closely arranged energy detectors, M≥2, and the detection coverage of the energy detector group is at least equal to the distance between two adjacent interference fringes.

[0087] The peak-seeking area determination module 32 is used to determine the target peak-seeking area according to the high and low distribution of the detection voltages of the M energy detectors when the laser to be measured forms actual interference fringes in the focal plane. The target peak-seeking area is the peak-seeking area corresponding to the position of a specific energy detector among the M energy detectors.

[0088] The peak-finding module 33 is used to find the effective peak position of the actual interference fringes in the target peak-finding area.

[0089] A fourth exemplary embodiment of the present disclosure provides an apparatus for rapidly measuring laser wavelength.

[0090] Figure 8 4 is a structural block diagram of a device for rapidly measuring laser wavelength according to an embodiment of the present disclosure. Figure 8In the figure, the optical connection relationship is indicated by the dotted line, and the electrical and / or communication connection relationship is indicated by the solid line.

[0091] Reference Figure 8 As shown, the device 4 for rapidly measuring the laser wavelength of this embodiment includes: an FP etalon 41 arranged on the measurement optical path of the laser to be measured, a lens 42, a beam splitting element 43, an energy detector group 45, an optical imaging element 44, a peak-seeking area determination module 46, a peak-seeking module 47, an interference fringe radius determination module 48, and a wavelength determination module 49.

[0092] The laser to be measured passes through the FP etalon 41, lens 42 and beam splitter 43 in sequence to form two outgoing lights; the energy detector group 45 is arranged on the focal plane of one outgoing light, and the optical imaging element 44 is arranged on the focal plane of the other outgoing light.

[0093] The energy detector group 45 includes M energy detectors that are closely arranged, where M≥2, and the detection coverage of the energy detector group is at least equal to the distance between two adjacent interference fringes.

[0094] The peak-seeking region determination module 46 is used to determine the target peak-seeking region based on the high and low distribution of the detection voltages of the M energy detectors when the laser to be measured passes through the FP etalon, the lens, and the beam splitting element to form actual interference fringes on the optical imaging element. The target peak-seeking region is the peak-seeking region corresponding to the position of a specific energy detector among the M energy detectors.

[0095] The peak-finding module 47 is used to find the effective peak position of the actual interference fringes in the target peak-finding area of ​​the optical imaging element.

[0096] The interference fringe radius determination module 48 is used to determine the interference fringe radius according to the effective peak position of the actual interference fringe.

[0097] The wavelength determination module 49 is used to determine the wavelength of the laser to be measured according to the spacing of the FP etalon, the focal length of the lens and the interference fringe radius.

[0098] According to the modules, submodules, units, and subunits of the embodiments of the present invention, any multiple or at least part of the functions of any multiple thereof can be implemented in one module. According to the modules, submodules, units, and subunits of the embodiments of the present invention, any one or more thereof can be split into multiple modules for implementation. According to the modules, submodules, units, and subunits of the embodiments of the present invention, any one or more thereof can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or can be implemented by hardware or firmware of any other reasonable way of integrating or packaging the circuit, or implemented in any one of the three implementation modes of software, hardware, and firmware or in an appropriate combination of any of them. Alternatively, according to the modules, submodules, units, and subunits of the embodiments of the present invention, one or more thereof can be at least partially implemented as a computer program module, which can perform the corresponding function when the computer program module is run.

[0099] For example, any number of the peak-finding module 47, the interference fringe radius determination module 48, and the wavelength determination module 49 can be combined into one module, or any one of the modules can be split into multiple modules. Alternatively, at least part of the functionality of one or more of these modules can be combined with at least part of the functionality of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the peak-finding region determination module 46, the peak-finding module 47, the interference fringe radius determination module 48, and the wavelength determination module 49 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application-specific integrated circuit (ASIC), or can be implemented in hardware or firmware by any other reasonable means of integrating or packaging the circuit, or implemented in any one of the three implementation methods of software, hardware, and firmware, or in any appropriate combination of any of them. Alternatively, at least one of the peak-finding region determination module 46, the peak-finding module 47, the interference fringe radius determination module 48, and the wavelength determination module 49 can be at least partially implemented as a computer program module, which can perform the corresponding function when the computer program module is executed.

[0100] In summary, the present disclosure provides a method and device for rapid peak finding and rapid measurement of laser wavelength. When the laser wavelength changes, the interference fringe peak will move in the focal plane. By setting an energy detector group, the detection voltage of the energy detectors at the positions corresponding to different areas of the interference fringe in the energy detector group will change accordingly with the position number of the reflection fringe peak. Therefore, the peak finding area corresponding to the position of a specific energy detector is determined as the target peak finding area according to the relative highs and lows of the detection voltages of multiple energy detectors in the energy detector group, thereby achieving rapid prediction of the interference fringe peak area, shortening the wavelength calculation time, and realizing real-time and high-speed measurement of the wavelength, which is beneficial to improving the wavelength stability of the laser during operation. It can be applied to the wavelength measurement of the excimer laser to improve the output spectrum stability of the excimer laser.

[0101] It should be noted that the ordinal numbers used in the specification and claims, such as "first," "second," "third," etc., to modify the corresponding elements, do not themselves mean that the elements have any ordinal numbers, nor do they represent the order of one element relative to another, or the order in the manufacturing method. The use of these ordinal numbers is only used to clearly distinguish one element with a certain name from another element with the same name.

[0102] Furthermore, the word "comprises" or "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0103] Unless there are technical obstacles or contradictions, the above-mentioned various embodiments of the present disclosure can be freely combined to form additional embodiments, and these additional embodiments are all within the protection scope of the present disclosure.

[0104] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A rapid peak-finding method for laser wavelength measurement, characterized in that: include: An energy detector group is pre-arranged on the focal plane where the laser to be measured is to form multi-level interference fringes. The energy detector group includes M energy detectors arranged closely together, where M is greater than or equal to 2. The detection coverage of the energy detector group is at least equal to the distance between two adjacent levels of interference fringes. The M energy detectors are arranged in an active region of interference fringes of one level. The active region of interference fringes of one level is the position interval of the interference fringes of that level corresponding to all wavelengths within the wavelength measurement range. When the laser to be measured forms actual interference fringes on the focal plane, a target peak-seeking area is determined according to the high and low distribution of the detection voltages of the M energy detectors, where the target peak-seeking area is the peak-seeking area corresponding to the position of a specific energy detector among the M energy detectors; and The effective peak position of the actual interference fringe is found in the target peak-finding area.

2. The rapid peak search method according to claim 1, characterized in that: The specific energy detector is an energy detector with the highest detection voltage among the M energy detectors, and the target peak-seeking area covers and is larger than the detection coverage range of the specific energy detector.

3. The rapid peak-finding method according to claim 1, characterized in that: In the peak-searching regions corresponding to the respective positions of the M energy detectors, there is an overlapping region between two adjacent peak-searching regions.

4. A method for rapidly measuring laser wavelength, characterized in that: include: An FP etalon, a lens, and a beam splitter are arranged on a measurement optical path. The laser to be measured sequentially passes through the FP etalon, the lens, and the beam splitter to form two paths of outgoing light. An energy detector group is arranged on the focal plane of one path of outgoing light, and an optical imaging element is arranged on the focal plane of the other path of outgoing light. The energy detector group includes M closely arranged energy detectors, where M is greater than or equal to 2. The detection coverage range of the energy detector group is at least equal to the distance between two adjacent levels of interference fringes. The M energy detectors are arranged in an active region of interference fringes of one level. The active region of interference fringes of one level is the position interval of the interference fringes of that level corresponding to all wavelengths within the wavelength measurement range. When the laser to be measured passes through the FP etalon, the lens, and the beam splitting element to form actual interference fringes on the optical imaging element, a target peak-seeking area is determined based on the high and low distribution of the detection voltages of the M energy detectors, where the target peak-seeking area is the peak-seeking area corresponding to the position of a specific energy detector among the M energy detectors; Searching for an effective peak position of the actual interference fringe in the target peak-seeking region of the optical imaging element; Determining the interference fringe radius according to the effective peak position of the actual interference fringe; and The wavelength of the laser to be measured is determined according to the spacing of the FP etalon, the focal length of the lens, and the radius of the interference fringe.

5. The method according to claim 4, characterized in that The specific energy detector is an energy detector with the highest detection voltage among the M energy detectors, and the target peak-seeking area covers and is larger than the detection coverage range of the specific energy detector.

6. The method according to claim 4, characterized in that The wavelength of the laser to be measured is determined according to the spacing of the FP etalon, the focal length of the lens, and the interference fringe radius to satisfy the following expression: ， in, Indicates the wavelength of the laser to be measured; Indicates the distance between the two glass plates in the FP etalon; Indicates the focal length of the lens; represents the radius of the mth level bright fringe, The size of is determined by the number of pixels between two symmetrical effective peak positions of the same level of bright fringe in the optical imaging unit and the size of a single pixel; A constant associated with the order m of the bright fringe corresponding to the effective peak position.

7. A rapid peak-finding device for laser wavelength measurement, characterized in that: include: An energy detector group is arranged on the focal plane where the laser to be measured is to form multi-level interference fringes, the energy detector group comprising M closely arranged energy detectors, M ≥ 2, and the detection coverage range of the energy detector group is at least equal to the distance between two adjacent levels of interference fringes, wherein the M energy detectors are arranged in an active area of ​​interference fringes of one level, and the active area of ​​interference fringes of one level is the position interval of the interference fringes of that level corresponding to all wavelengths within the wavelength measurement range; a peak-seeking region determining module, configured to determine a target peak-seeking region based on the high and low distribution of detection voltages of the M energy detectors when the laser to be measured forms actual interference fringes on the focal plane, wherein the target peak-seeking region is a peak-seeking region corresponding to a position of a specific energy detector among the M energy detectors; and The peak-finding module is used to find the effective peak position of the actual interference fringe in the target peak-finding area.

8. A device for rapidly measuring laser wavelength, characterized in that: include: An FP etalon, a lens, and a beam splitter are arranged on the measurement optical path of the laser to be measured, wherein the laser to be measured sequentially passes through the FP etalon, the lens, and the beam splitter to form two outgoing light paths; an energy detector group is arranged on the focal plane of one outgoing light path, and an optical imaging element is arranged on the focal plane of the other outgoing light path; wherein the energy detector group includes M energy detectors arranged closely together, where M ≥ 2, and the detection coverage range of the energy detector group is at least equal to the distance between two adjacent levels of interference fringes, wherein the M energy detectors are arranged in an active region of interference fringes of one level, and the active region of interference fringes of one level is the position interval of the interference fringes of that level corresponding to all wavelengths within the wavelength measurement range; a peak-seeking region determining module, configured to determine a target peak-seeking region based on the high and low distribution of detection voltages of the M energy detectors when the measured laser passes through the FP etalon, the lens, and the beam splitting element to form actual interference fringes on the optical imaging element, wherein the target peak-seeking region is a peak-seeking region corresponding to a position of a specific energy detector among the M energy detectors; A peak-finding module, configured to find an effective peak position of the actual interference fringe in the target peak-finding region of the optical imaging element; an interference fringe radius determining module, configured to determine the interference fringe radius according to the effective peak position of the actual interference fringe; and The wavelength determination module is used to determine the wavelength of the laser to be measured according to the spacing of the FP etalon, the focal length of the lens and the radius of the interference fringe.

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