WO2021196723A1 - 激光器波长测量装置及方法 - Google Patents

激光器波长测量装置及方法 Download PDF

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Publication number
WO2021196723A1
WO2021196723A1 PCT/CN2020/135615 CN2020135615W WO2021196723A1 WO 2021196723 A1 WO2021196723 A1 WO 2021196723A1 CN 2020135615 W CN2020135615 W CN 2020135615W WO 2021196723 A1 WO2021196723 A1 WO 2021196723A1
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Prior art keywords
etalon
optical path
laser
laser beam
laser wavelength
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PCT/CN2020/135615
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English (en)
French (fr)
Inventor
刘广义
江锐
韩晓泉
赵江山
沙鹏飞
殷青青
张华�
Original Assignee
北京科益虹源光电技术有限公司
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Priority to EP20928776.2A priority Critical patent/EP4124841A4/en
Priority to JP2022560158A priority patent/JP7461497B2/ja
Priority to KR1020227038178A priority patent/KR20230020389A/ko
Priority to US17/915,434 priority patent/US11971307B2/en
Publication of WO2021196723A1 publication Critical patent/WO2021196723A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
    • G01J9/02—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods
    • G01J9/0246—Measuring optical wavelength
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/7055—Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
    • G03F7/70575—Wavelength control, e.g. control of bandwidth, multiple wavelength, selection of wavelength or matching of optical components to wavelength
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
    • G03F7/7085—Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
    • G01J9/02—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods
    • G01J2009/0234—Measurement of the fringe pattern
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J9/00—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength
    • G01J9/02—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods
    • G01J2009/0257—Measuring optical phase difference; Determining degree of coherence; Measuring optical wavelength by interferometric methods multiple, e.g. Fabry Perot interferometer

Definitions

  • the present disclosure relates to the technical field of laser spectrum measurement, in particular to a laser wavelength measurement device and method.
  • Laser is an important light source equipment in modern industry. It can be used in lighting, laser processing, projection display, optical communication, material analysis, test and measurement, semiconductor processing and other fields. ), the laser is required to have high wavelength stability. Therefore, it is required to design a corresponding laser wavelength measurement device in the laser, and implement closed-loop feedback on the wavelength of the laser according to the measurement result to ensure the stable wavelength output of the laser.
  • excimer lasers are the main light source used in semiconductor photolithography.
  • the center wavelength of the ArF excimer laser is 193.4nm
  • the center wavelength of the KrF excimer laser is 248.3nm.
  • the change of the center wavelength of the laser directly affects the change of the exposure focal plane of the lithography machine, which will cause the exposure line to become wider, resulting in a decrease in the yield of the chip.
  • the center wavelength stability of the laser is required to be higher than 0.05pm
  • the center wavelength stability of the laser is required to be higher than 0.03pm.
  • the wavelength of the laser is measured in real time by the wavelength measuring device, and closed-loop control is performed, so as to realize the stable output of the laser wavelength.
  • Dispersion method includes prism dispersion and grating dispersion.
  • Interferometry includes Fourier transform method and Fabry-Perot etalon (hereinafter referred to as FP etalon) method:
  • the method based on prism dispersion and low-order blazed grating has low accuracy in measuring wavelength, and cannot achieve high-precision wavelength measurement.
  • wavelength measurement based on the Fourier transform method requires mechanical movement of components, which is poor in stability and cannot achieve high-speed wavelength measurement.
  • the existing methods for high-speed and high-precision laser wavelength measurement mainly include the echelle method and the FP etalon method.
  • the echelle grating is used to measure the center wavelength of the laser, and the echelle diffraction order is high, which can realize high-precision center wavelength measurement.
  • the echelle wavelength meter is large in size and is not suitable for on-line measurement of laser wavelengths. It is generally used for off-line measurement.
  • the FP etalon method because of its small size and high spectral resolution, is an ideal choice for lasers to measure wavelengths online. With the FP etalon method, after the laser passes through the FP etalon, interference fringes are generated, and the wavelength of the incident laser is obtained according to the position of the peak of the interference fringe.
  • the existing FP etalon has a relatively small measurement wavelength range, and it is generally impossible to achieve a wide-range and high-precision wavelength measurement with one FP etalon.
  • the FP etalon and grating are used to measure the wavelength, and the incident laser is divided into two beams and irradiated on the grating and FP etalon respectively.
  • the grating is used for rough measurement of wavelength, and the FP etalon is used for precise measurement of wavelength. , So as to get the precise value of the wavelength of the laser.
  • two FP etalons can also be used to measure the wavelength of the laser.
  • One FP etalon has a relatively large measurement range and is used for rough measurement of the center wavelength
  • the other FP etalon has a relatively small measurement range and is used for fine measurement of the center wavelength.
  • a beam splitter is used to divide the laser beam of the laser into two beams and irradiate them on two FP etalons respectively, and then calculate the interference fringes of the two FP etalons to obtain the rough and precise wavelength measurement results, thereby obtaining the precise value of the laser wavelength .
  • two FP etalons connected in series can be used to measure the wavelength.
  • One FP etalon roughly determines the wavelength deviation, and the other FP etalon accurately determines the wavelength deviation.
  • Obtain the wavelength deviation of the laser so as to maintain the stability of the laser wavelength.
  • the wavelength measurement device Based on the above-mentioned laser wavelength measurement method, at least two sets of wavelength measurement devices are used, one (or more) is used for rough wavelength measurement, and the other uses FP etalon method for precise wavelength measurement. It is necessary to split the incident laser beam.
  • the wavelength measurement device cannot achieve a complete common optical path, and the device is more complicated.
  • the final wavelength measurement result only depends on the precision measurement result of one FP etalon, which is easily affected by the external environment, and the wavelength measurement accuracy and stability are relatively poor.
  • a laser wavelength measurement device including: a first optical path component and a second optical path component, the first optical path component is used to homogenize the laser beam emitted by the laser; and the second optical path component and the second optical path component
  • An optical path component constitutes a laser wavelength measurement optical path, which is used to perform hierarchical imaging of the laser beam after homogenization of the first optical path component.
  • the second optical path component includes: an FP etalon component and an optical classifier, after homogenization treatment The laser beam passes through the FP etalon assembly to generate interference fringes; and the optical classifier is arranged after the FP etalon assembly in the laser wavelength measurement optical path, and is used to deflection processing the laser beam passing through the FP etalon assembly to achieve Graded imaging.
  • the first optical path component includes: a beam splitter and a homogenizing component arranged in sequence along the laser wavelength measurement optical path; wherein the beam splitter is used to reflect a part of the laser beam emitted by the laser to the laser wavelength measurement Optical path; The homogenization component is used to homogenize the laser beam reflected by the beam splitter to the laser wavelength measurement optical path.
  • the homogenization component includes: an optical homogenization element, a first converging mirror, and a reflecting mirror that are sequentially arranged along the laser wavelength measurement optical path; wherein the optical homogenization element is used to homogenize the laser beam, In order to reduce the influence of the quality of the laser beam on the measurement accuracy; the first condensing mirror is used to converge the laser beam after the homogenization treatment of the optical homogenizing element into the second optical path assembly; the reflecting mirror is used to converge the first converging mirror The laser beam is reflected into the second optical path component.
  • the second optical path component further includes: a homogenizing plate, a field diaphragm, and a collimator arranged in sequence along the laser wavelength measuring optical path, wherein the homogenizing plate is correspondingly arranged in the laser wavelength measuring optical path After the first optical path component, it is used to further homogenize the laser beam that passes through the first optical path component and enters the second optical path component; the field diaphragm is used to control the laser beam after the homogenization treatment of the homogenizing plate.
  • the imaging range in hierarchical imaging; the collimator is correspondingly arranged before the FP etalon assembly in the laser wavelength measurement optical path to ensure the collimation characteristics of the laser beam incident on the FP etalon assembly.
  • the second optical path component further includes: an aperture stop, which is arranged between the FP etalon component and the optical classifier in the laser wavelength measurement optical path, and is used to limit the laser beam passing through the FP etalon component The direction.
  • the second optical path assembly further includes: a second converging lens and an imaging device arranged in sequence along the laser wavelength measurement optical path, wherein the second converging lens is disposed in the optical grading device in the laser wavelength measurement optical path. After the detector, it is used to converge the laser beam passing through the optical classifier into the imaging device; the imaging device is used to image the laser beam passing through the second converging lens.
  • the FP etalon assembly includes: a housing, a first FP etalon, and a second FP etalon.
  • the housing is used to form a sealed cavity of the FP etalon assembly;
  • the cavity is used to generate the first interference fringe corresponding to the hierarchical imaging;
  • the second FP etalon corresponding to the first FP etalon is arranged in the sealed cavity and is used to generate the second interference fringe corresponding to the hierarchical imaging.
  • first FP etalon and the second FP etalon satisfy:
  • FSR 1 is the free spectral range of the first FP etalon
  • FSR 2 is the free spectral range of the second FP etalon
  • the housing includes: a first sealing groove, a first sealing ring, and a first window, and a second sealing groove, a second sealing ring, and a second window, the first sealing groove corresponding to the housing
  • the first sealing ring is matched with the first sealing groove and arranged on the light entrance;
  • the first window is matched with the first sealing ring and is arranged in the first sealing groove;
  • the second sealing groove corresponds to the light output of the housing
  • the second sealing ring is matched with the second sealing groove and is arranged on the light outlet;
  • the second window is matched with the second sealing ring and is arranged in the second sealing groove; wherein, the first window and the second window are both provided with Anti-reflection film, or the normal line of the light entrance surface and/or the normal line of the light exit surface of the first window part and the incident direction of the laser beam are at a first angle, and/or the normal line of the light entrance surface of the second window part And/or the normal line of the light-emitting surface
  • the optical classifier includes: a first deflection member and a second deflection member, the first deflection member has a first wedge angle, and is used to perform a laser beam passing through the first FP etalon Deflection processing; the second deflection member has a second wedge angle, and the second wedge angle is set corresponding to the first wedge angle of the first deflection member, and is used for deflection processing of the laser beam passing through the second FP etalon .
  • the optical classifier includes: a third deflection member having a third wedge angle for deflection processing of the laser beam passing through the first FP etalon, or for deflection processing of the laser beam passing through the second FP standard The laser beam of the tool is deflected.
  • the optical classifier includes: a fourth deflection member, including: a light-transmitting hole, which is arranged on the fourth deflection member parallel to the direction of the laser beam; wherein, when the fourth deflection member When the laser beam passing through the first FP etalon is deflected by the first FP etalon, the transparent hole is used to make the laser beam passing through the second FP etalon pass through the transparent hole; when the fourth deflector pair passes through the second FP standard When the laser beam of the tool is subjected to deflection processing, the light transmission hole is used to allow the laser beam passing through the first FP etalon to pass through the light transmission hole.
  • a fourth deflection member including: a light-transmitting hole, which is arranged on the fourth deflection member parallel to the direction of the laser beam; wherein, when the fourth deflection member When the laser beam passing through the first FP etalon is deflected by the first FP etalon, the transparent hole is used
  • a laser wavelength measurement system including: the above-mentioned laser wavelength measurement device and a laser, and the laser is used to generate a laser beam incident to the laser wavelength measurement device.
  • Another aspect of the present disclosure discloses a laser wavelength measurement method, which is applied to the above-mentioned laser wavelength measurement device to realize the measurement of the laser wavelength of the laser.
  • FIG. 1A is a schematic diagram of the structural composition of a laser wavelength measuring device in an embodiment of the present disclosure
  • 1B is a schematic diagram of the structural composition of a laser wavelength measuring device in another embodiment of the present disclosure.
  • FIG. 2 is a schematic diagram of the structural composition of the FP etalon assembly and an optical classifier of the laser wavelength measurement device in an embodiment of the present disclosure
  • FIG. 3 is a schematic diagram of the structural composition of another optical classifier of the laser wavelength measurement device in an embodiment of the present disclosure
  • FIG. 4 is a schematic structural composition diagram of another optical classifier of the laser wavelength measurement device in the embodiment of the present disclosure.
  • FIG. 5 is an imaging result of laser beam interference fringes corresponding to the FP etalon assembly and optical classifier shown in FIG. 2 of the laser wavelength measuring device in an embodiment of the present disclosure on a CCD imaging device;
  • FIG. 6 is a schematic diagram of the distribution of the interference fringes corresponding to the laser wavelength of the laser of the laser wavelength measuring device in the embodiment of the present disclosure.
  • the present disclosure discloses a laser wavelength Measuring device and method.
  • the laser wavelength measurement device 2 includes: a first optical path component and a second optical path component.
  • the first optical path component is used to emit light to the laser 1.
  • the laser beam is homogenized; and the second optical path component is arranged corresponding to the first optical path component, and forms a laser wavelength measurement optical path with the first optical path component, and the second optical path component is used to homogenize the laser after the first optical path component is homogenized.
  • the beam performs hierarchical imaging.
  • the laser beam to be measured generated by the laser 1 enters the first optical path component, it enters the second optical path component along the above-mentioned laser wavelength measurement optical path through the first optical path component, and performs hierarchical imaging in the second optical path component to obtain the measurement result. For example, it corresponds to the interference fringes of the laser beam.
  • the second optical path assembly includes: an FP etalon assembly 11 and an optical classifier 13.
  • the FP etalon assembly 11 is used to generate interference fringes corresponding to the laser beam; specifically, the laser beam passing through the FP etalon assembly 11 After being irradiated on the imaging device 15, the imaging device 15 detects and obtains its corresponding interference fringes accordingly. That is, the laser beam after the homogenization process passes through the FP etalon assembly to produce interference fringes.
  • the FP etalon assembly 11 may include multiple FP etalons.
  • the wavelength measurement result can be the average of the measurement results of at least two FP etalons, which further improves the accuracy of wavelength measurement.
  • the wavelength measurement range can also be the product of the free spectral range FSR of at least two FP etalons, which further improves the wavelength Measuring range.
  • the optical classifier 13 is correspondingly disposed after the FP etalon assembly 11 in the laser wavelength measurement optical path, and is used to perform deflection processing on the laser beam passing through the FP etalon assembly 11 to achieve hierarchical imaging.
  • the laser beam is incident on the optical classifier 13 through the FP etalon assembly 11 along the above-mentioned laser wavelength measurement optical path.
  • the optical classifier 13 can deflect the laser beam into two beams, so that the interference fringes corresponding to the laser beam are imaged separately on the imaging device 15. This helps to obtain the wavelength of the incident laser beam by calculating the intensity positions of the two interference fringes.
  • the FP etalon assembly 11 of the present disclosure enables at least two FP etalons to share the same optical path for interference imaging, with a compact structure, small size, simple design, and high stability; with the cooperation of the optical classifier 13, the laser can be simultaneously realized Accurate measurement of the laser wavelength with a large wavelength measurement range, suitable for online measurement of laser wavelength and corresponding closed-loop control feedback.
  • the first optical path component includes: a beam splitter 3 and a light homogenizing component 4 arranged in sequence along the laser wavelength measuring optical path; wherein the laser 1 generates the laser to be measured
  • the light beam is incident on the laser wavelength measuring device 2.
  • the laser beam to be measured is incident into the first optical path component.
  • the laser beam to be measured is irradiated on the beam splitter 3.
  • the beam splitter 3 is a flat glass or glass with a wedge angle, which is used to transmit most of the light through the beam splitter 3, and also It is used to reflect a part of the laser beam emitted by the laser to the laser wavelength measuring optical path, that is, to make part of the laser beam to be measured enter the homogenizing component in the first optical path component after reflection.
  • the homogenization component 4 is correspondingly arranged after the beam splitter 3 in the laser wavelength measurement optical path, and is used to homogenize the laser beam reflected by the beam splitter 3 to the laser wavelength measurement optical path.
  • the homogenizing component 4 includes: an optical homogenizing element 5, a first converging mirror 6 and a reflecting mirror 7 arranged in sequence along the laser wavelength measurement optical path.
  • the optical homogenizing element 5 is used to homogenize the laser beam to reduce the influence of the quality of the laser beam on the measurement accuracy.
  • the optical homogenizing element 5 can be a microlens array, an optical integrator, or a diffractive optical element (DOE), etc. .
  • the first converging lens 6 is used to converge the laser beam after the homogenization treatment of the optical homogenizing element 5 into the second optical path assembly.
  • a reflecting mirror 7 can also be provided between the second optical path component and the first condensing mirror 6, a reflecting mirror 7 can also be provided.
  • the reflecting mirror 7 is used to reflect the laser beam condensed by the first converging mirror 6 to the second optical path component.
  • the mirror 7 can be coated with a high-reflection film on the reflective surface to enhance the ability to reflect the laser beam.
  • the path of the laser wavelength measurement optical path can be changed by the reflector 7, so that the structure of the laser wavelength measurement device 2 is more compact, and the volume of the laser wavelength measurement device 2 can be reduced.
  • the second optical path assembly further includes: a homogenizing plate 8, a field diaphragm 9, and a collimator 10 arranged in sequence along the laser wavelength measurement optical path, wherein After being condensed by the first converging mirror 6, the laser beam reflected by the reflecting mirror 7 of the first optical path assembly is reflected to the homogenizing sheet 8 in the second optical path assembly, and the homogenizing sheet 8 is correspondingly arranged in the laser wavelength measurement optical path After the reflector 7 of the first optical path component, it is used to further homogenize the laser beam incident to the second optical path component through the first optical path component.
  • the homogenizing sheet 8 may be ground glass or other light homogenizing effect. element.
  • the field diaphragm 9 is used to control the imaging range of the laser beam in the hierarchical imaging after the homogenization sheet 8 is further homogenized, that is, to control the imaging range of the interference fringes on the imaging surface of the imaging device 15.
  • the collimator lens 10 is correspondingly arranged before the FP etalon assembly 11 in the laser wavelength measurement optical path, and is used to ensure the collimation characteristics of the laser beam incident on the FP etalon assembly 11, and make it pass through the homogenizing plate 8 and the field of view light in sequence.
  • the laser beam of the stop 9 passes through the collimator lens 10 and enters the FP etalon assembly 11.
  • the second optical path component further includes: an aperture stop 12, which is arranged between the FP etalon component 11 and the optical classifier 13 in the laser wavelength measurement optical path , Used to limit the direction of the laser beam passing through the FP etalon assembly 11.
  • an aperture stop 12 which is arranged between the FP etalon component 11 and the optical classifier 13 in the laser wavelength measurement optical path , Used to limit the direction of the laser beam passing through the FP etalon assembly 11.
  • the laser beams passing through the two FP etalons pass through the aperture stop 12, which can prevent the two laser beams from crossing.
  • the at least two FP etalons in the FP etalon assembly 11 may also include three FP etalons or more. Specifically, as shown in FIG. 1B, the FP etalon assembly 11 includes three FP etalons (FP1, FP2, and FP3).
  • the second optical path assembly further includes: a second converging lens 14 and an imaging device 15 arranged in sequence along the laser wavelength measuring optical path, wherein the second converging lens 14 It is installed after the optical classifier 13 in the laser wavelength measurement optical path, and is used to converge the laser beam passing through the optical classifier 13 into the imaging device 15; the imaging device 15 is used to perform the laser beam
  • the imaging device 15 may be a CCD imaging camera. Specifically, the laser beam is incident on the optical classifier 13 after passing through the aperture stop 12.
  • the optical classifier 13 deflects the beams corresponding to different incident positions into different exit angles, and then enters the second condensing lens 14, and finally Through the converging action of the second converging lens 14, the two laser beams are incident on the imaging device 15 to complete imaging without mutual influence. Because of the existence of the optical classifier 13, the light passing through the FP etalon FP1 and FP etalon FP2 is deflected at different angles, so the interference fringes of the FP etalon FP1 and FP etalon FP2 can be imaged at different positions of the imaging device 15. , Choose a proper deflection angle, you can get different interference fringes on the imaging device 15.
  • Figure 5 shows the interference fringes of FP etalon FP1 and FP etalon FP2 obtained on a CCD imaging camera. The interference fringes of FP1 are on the left and the interference fringes of FP2 are on the right.
  • the FP etalon assembly 11 includes: a housing 16, a first FP etalon FP1, and a second FP etalon FP2, that is, in the present disclosure
  • the FP etalon assembly of the laser wavelength measuring device 2 can be designed as two FP etalons.
  • the FP etalon assembly 11 may also include a third FP etalon FP3, which is arranged between the first FP etalon FP1 and the second FP etalon FP2.
  • the housing 16 is used to form a sealed cavity of the FP etalon assembly 11, and the sealed cavity is used to seal the first FP etalon FP1 and the second FP etalon FP2 built therein.
  • the first FP etalon FP1 is arranged in the sealed cavity to correspond to the first interference fringes generated on the imaging device 15;
  • the second FP etalon FP2 is arranged in the sealed cavity corresponding to the first FP etalon FP1. It corresponds to the second interference fringe that produces hierarchical imaging.
  • the first FP etalon FP1 is arranged above the sealed cavity
  • the second FP etalon FP2 is correspondingly arranged below the first FP etalon FP1
  • the first FP etalon FP1 and the second FP etalon FP2 can satisfy:
  • FSR 1 is the free spectral range of the first FP etalon FP1
  • FSR2 is the free spectral range of the second FP etalon FP2.
  • FSR2 similar FP1 first FP etalon free spectral range FSR 1 and the second path FP etalon free spectral path FP2.
  • FSR 2 20.5pm.
  • the two FP etalons when one of the FP etalons (such as the first After one FP etalon FP1) reaches a free spectral range FSR 1 , because the free spectral range FSR2 of the second FP etalon FP2 is slightly different from the free spectral range FSR 1 of the first FP etalon FP1, the two correspond to each other.
  • the interference fringes will not repeat, so the wavelength measurement range of the laser wavelength measurement device 2 of the present disclosure is expanded, and the wavelength measurement range can achieve at least 410 pm (that is, the product of the two FSR 1 ⁇ FSR 2 ), which satisfies the excimer laser Wavelength measurement requirements.
  • the two FP etalons enable the laser wavelength measuring device 2 to have both high spectral resolution.
  • the wavelength measurement of the laser wavelength measuring device 2 in the embodiment of the present disclosure is further described as follows:
  • the laser beam wavelength of the laser incident on the laser wavelength measurement optical path ie the center wavelength ⁇ of the laser under test
  • ⁇ is the center wavelength of the laser
  • n is the refractive index of the gas in the FP etalon
  • d is the spacing of the FP etalon
  • m is the order of the interference fringes of the FP etalon
  • ⁇ is the emission of the laser beam corresponding to the FP etalon.
  • the center wavelength ⁇ of the laser measured by the FP etalon can be obtained according to the radius r of the interference fringe corresponding to the FP etalon.
  • a first FP etalon can be obtained FP1 and FP2 second FP etalon free spectral path respectively satisfies the following formula (5) And (6):
  • ⁇ FP1 ⁇ 1 +N ⁇ FSR 1
  • ⁇ FP2 ⁇ 2 +M ⁇ FSR 2
  • N and M are integers. Different integers N and M can be selected within a certain range to minimize ⁇ FP1 - ⁇ FP2 .
  • the center wavelength ⁇ laser of the laser is:
  • the measured center wavelength ⁇ laser of the laser is the average value of the measured wavelengths of the two FP etalons (that is, the first FP etalon FP1 and the second FP etalon FP2), and its stability is higher than that of a single FP.
  • the measurement result of the etalon also realizes the wavelength measurement range.
  • the free spectral ranges of the three FP etalons in the FP etalon assembly 11 are also required to be similar.
  • the third etalon FP3 etalon is precisely measured
  • the wavelength process is the same as that of the first FP etalon FP1 and the second FP etalon FP2.
  • the center wavelength of the laser is the average value of the three PF etalons' respective precision measured wavelengths, which can further improve the measurement accuracy of the laser center wavelength. .
  • the situation where there are more FP etalons in other FP etalon assemblies 11 is also applicable, and will not be repeated here.
  • the housing 16 of the FP standard assembly 11 includes: a first sealing groove, a first sealing ring 18a and a first window 17a, and a second The sealing groove, the second sealing ring 18b and the second window 17b are used to ensure a better sealing effect on the sealed cavity of the housing 16.
  • the first sealing groove is arranged corresponding to the light inlet of the housing 16, as shown in the light path arrow in FIG.
  • the edge of the light inlet is recessed in the annular closed sealing groove structure designed by the housing 16.
  • the first sealing ring includes a first fixing groove and a first main body groove, which are respectively used for correspondingly setting the first sealing ring 18a and the first window 17a.
  • the first sealing ring 18a is matched with the first sealing groove and arranged on the light inlet. Specifically, the first sealing ring 18a is built in the first fixing groove, and the first sealing ring 18a is an annular closure designed around the edge of the light inlet.
  • the physical structure, whose shape and size are matched with the shape and size of the above-mentioned first fixing groove, is designed to fit the first sealing ring 18a exactly in the first fixing groove.
  • the first window member 17a matches the first sealing ring 18a and is arranged in the first sealing groove; specifically, the first window member 17a is built in the first main body groove, and the size and shape of the first window member 17a and the first main body groove
  • the matching design makes the first window member 17a fit exactly in the first main body groove so as to cooperate with the first sealing ring 18a to seal the light inlet intact.
  • the second sealing groove is arranged corresponding to the light exit of the housing 16; as shown in the light path arrow in FIG. 2, the light transmission opening on the right side of the housing 16 corresponding to the second window 17b is the light exit.
  • the inner edge of the rim is recessed in the annular closed sealing groove structure designed by the housing 16.
  • the second sealing ring includes a second fixing groove and a second main body groove, which are respectively used for correspondingly setting the second sealing ring 18b and the first window 17b.
  • the second sealing ring 18b is matched with the second sealing groove and arranged on the light exit; specifically, the second sealing ring 18b is built in the second fixing groove, and the second sealing ring 18b is an annular closed solid structure designed around the edge of the light exit , Its shape and size are designed to match the shape and size of the above-mentioned second fixing groove, so as to fit the second sealing ring 18b exactly in the second fixing groove.
  • the second window 17b matches the second sealing ring 18b and is arranged in the second sealing groove; specifically, the second window 17b is built in the second main body groove, and the size and shape of the second window 17b and the second main body groove
  • the matching design enables the second window member 17b to be installed in the second main body groove so as to cooperate with the second sealing ring 18b to seal the light outlet intact.
  • both the first sealing ring 18a and the second sealing ring 18b can be made of materials with elastic deformation properties such as rubber or silica gel.
  • Both the first window member 17a and the second window member 17b can be made of materials with light-transmitting properties such as glass.
  • the first window member 17a and the second window member 17b have antireflection films, and/or the normal line of the light entrance surface and/or the normal line of the light exit surface of the first window member 17a is in line with the incident direction of the laser beam.
  • the first included angle, and/or the normal line of the light entrance surface and/or the normal line of the light exit surface of the second window member 17b and the incident direction of the laser beam form a second included angle
  • the first included angle or the second included angle is 5-10 degrees to reduce the influence of the reflected light on the first window 17a and the second window 17b on the laser wavelength measurement results.
  • the laser beam cannot be incident on the light entrance surface and/or light exit surface of the first window member 17a and/or the second window member 17b at a vertical angle.
  • the first window member 17ah and/or the second window member 17b may have a wedge angle structure; alternatively, the first window member 17a is placed at the light inlet at an oblique angle and sealed, and/or the second window The piece 17b is arranged at the light outlet at a certain oblique angle and sealed.
  • the incident direction of the incident laser beam is not perpendicular to the light entrance surface and the light exit surface of the first window member 17a.
  • the normal line of the light entrance surface or the normal line of the light exit surface of a window 17a is at a first angle with the incident direction of the laser beam, and the first included angle is 5-10 degrees; in the same way, the entrance of the second window 17b
  • the normal line of the light surface or the normal line of the light exit surface forms a second included angle with the incident direction of the laser beam, and the second included angle is 5 degrees to 10 degrees.
  • the first window 17a may not have a wedge angle structure.
  • it may be a flat glass, which is installed obliquely to the light inlet of the housing 16, and the incident direction of the laser beam is consistent with the first window.
  • the normal line of the light entrance surface and the normal line of the light exit surface of 17a are respectively at an angle of 5-10 degrees, that is, the incident direction of the incident laser beam is not perpendicular to the light entrance surface and/or light exit surface of the first window member 17a; Therefore, the second window 17b can be installed obliquely to the light outlet of the housing 16, and the details are not repeated here.
  • the light entrance surface is the surface on the optical element to which light is irradiated
  • the light exit surface is the surface from which the light exits on the optical element, which may generally be the back surface of the light entrance surface.
  • first FP etalon FP1 and the second FP etalon FP2 are in the same sealed environment to ensure the stability and accuracy of the laser wavelength measurement.
  • the optical classifier 13 includes: a first deflection member 19a and a second deflection member 19b, which are used to compare the optical classifier 13 The laser beam undergoes deflection processing.
  • the first deflector 19a has a first wedge angle for deflecting the laser beam passing through the first FP etalon FP1; the light incident surface of the first deflector 19a is perpendicular to the first FP etalon passing through In the incident direction of the laser beam of FP1, the light exit surface of the first deflection member 19a is an inclined surface, so that the light exit surface and the light entrance surface of the first deflection member 19a have an included angle corresponding to the first wedge angle.
  • a wedge angle may be provided corresponding to the top end of the first deflector 19a.
  • the second deflection member 19b has a second wedge angle, and the second wedge angle is set corresponding to the first wedge angle of the first deflection member 19a, and is used to deflect the laser beam passing through the second FP etalon FP2. Fold processing.
  • the light entrance surface of the second deflection element 19b is perpendicular to the incident direction of the laser beam passing through the second FP etalon FP2, and the light exit surface of the second deflection element 19b is an inclined surface, so that the light exit surface of the second deflection element 19b There is an included angle corresponding to the second wedge angle between the light entrance surface.
  • the first wedge angle may be equal to the second wedge angle
  • the second wedge angle may be set corresponding to the top end of the second deflector 19b.
  • the first deflection The top ends of the first deflection member 19a and the second deflection member 19b need to be opposite to each other.
  • the light entrance surfaces of 19a and the second deflection member 19b are level perpendicular to the light entrance direction.
  • the light entrance surface of the first deflector 19a may not be perpendicular to the incident direction of the laser beam passing through the first FP etalon FP1.
  • the entrance surface of the second deflector 19b The light surface may not be perpendicular to the incident direction of the laser beam passing through the first FP etalon FP1.
  • the first deflection member 19a and the second deflection member 19b may also be arranged opposite to each other at the top end.
  • the optical classifier 13 adopts the first deflection element 19a and the second deflector 19b respectively deflect the two light beams and change their respective exit angles to make their exit directions different, so that when they are incident on the imaging device 15 (such as a CCD imaging camera), the imaging device 15 It is possible to obtain interference fringes corresponding to different positions of the respective laser beams.
  • the imaging device 15 such as a CCD imaging camera
  • FIG. 1B there are three FP etalons in the FP etalon assembly 11, and the third FP etalon FP3 is arranged between the first FP etalon FP1 and the second FP etalon FP2.
  • the central optical axis of the third FP etalon FP3 and the central optical axis of the second converging lens 14 coincide correspondingly, the position in the optical classifier 13 corresponding to the third FP etalon FP3 can no longer be provided with a deflection member, That is, as shown in FIG.
  • the light beam passing through the third FP etalon FP3 can directly enter the center of the second converging lens 14 and directly enter the imaging device 15 after passing through the second converging lens 14. Therefore, those skilled in the art should understand that for a larger number of FP etalons in the FP etalon assembly 11, the optical path and the number and setting positions of the corresponding deflection parts can also be obtained accordingly. Do not repeat it.
  • the optical classifier 13 further includes: a third deflection member 21 having a third wedge angle for aligning the first FP
  • the laser beam G1 of the etalon FP1 is subjected to deflection processing, or the laser beam G2 of the second FP etalon FP2 is subjected to deflection processing.
  • the light entrance surface of the third deflection member 21 is perpendicular to the incident direction of the laser beam G1 (or laser beam G2), and the light exit surface of the third deflection member 21 is an inclined surface, so that the There is an included angle corresponding to the third wedge angle between the light exit surface and the light entrance surface.
  • the optical classifier 13 only has the function of deflecting the laser beam G1 (or laser beam G2) incident on the third deflection member 21, and for the other not incident on the third deflection member 21 As for the laser beam G2 (or the laser beam G1), it can be emitted directly without a deflection angle, and finally enters the imaging device 15 for imaging.
  • the optical classifier 13 can only be designed with one third deflection member 21, that is, it can realize the deflection of the two laser beams that are incident through, so that their exit directions are different, so that they are incident on the imaging device 15 (for example, When using a CCD imaging camera), the imaging device 15 can obtain interference fringes corresponding to different positions of the respective laser beams.
  • the third deflection member 21 only occupies the space at the upper end or the lower end of the original optical classifier 13, and has a small volume size, which can reduce the size of the optical classifier 13 to help the size of the laser measuring device of the present disclosure. Of shrinking.
  • the optical classifier 13 includes: a fourth deflection member 22, and the fourth deflection member 22 includes: a light-transmitting hole 23, which is parallel It passes through the fourth deflector 22 in the direction of the laser beam.
  • the fourth deflector 22 has a fourth wedge angle for deflecting the laser beam G1 passing through the first FP etalon FP1 , Or perform deflection processing on the laser beam G2 passing through the second FP etalon FP2.
  • the light entrance surface of the fourth deflection element 22 is perpendicular to the incident direction of the laser beam G1 (or laser beam G2), and the light exit surface of the fourth deflection element 22 is an inclined surface, so that the fourth deflection element 22 There is an included angle corresponding to the fourth wedge angle between the light exit surface and the light entrance surface.
  • a light-transmitting hole 23 can be penetrated on the fourth deflection member 22 near the top end of the fourth wedge angle, so that it is separated from the main body of the fourth deflection member 22 by a certain distance to avoid mutual influence.
  • the light transmission hole 23 is used to allow the laser beam G2 to pass through the light transmission hole 23; when the fourth deflection member 22 deflects the laser beam G2 During processing, the light-transmitting hole is used to allow the laser beam G1 to pass through the light-transmitting hole 23.
  • the optical classifier 13 can also be designed with only one fourth deflection member 22, that is, it can achieve the deflection of the two incident laser beams so that the exit directions are different, which is similar to the third deflection member 21.
  • the fourth deflection member 22 can occupy most of the space of the optical classifier 13, and its volume size can ensure the convenience of manufacturing.
  • the explanation of the optical classifier 13 in the foregoing embodiment is not a limitation thereof.
  • the first deflection member 19a, the second deflection member 19b, the third deflection member 21, the fourth deflection member 22, etc. may be
  • the deflection prism may also be an element or structure with a laser beam deflection effect, such as a mirror, a swing mirror, or a micro galvanometer.
  • FIG. 1A and FIG. 1B Another aspect of the present disclosure discloses a laser wavelength measurement system, as shown in FIG. 1A and FIG. 1B, which includes: the above-mentioned laser wavelength measurement device 2 and a laser 1.
  • the laser 1 is used to generate a laser beam incident on the laser wavelength measurement device 2
  • the center wavelength corresponding to the laser beam to be measured is obtained by the laser wavelength measuring device 2.
  • the laser 1 and the laser wavelength measuring device 2 are designed with online measurement and closed-loop control feedback.
  • Another aspect of the present disclosure discloses a laser wavelength measurement method, which is applied to the above-mentioned laser wavelength measurement device 2 and realizes the measurement of the center wavelength of the laser beam of the laser 1 according to the aforementioned laser wavelength measurement calculation process.
  • the laser wavelength measurement device includes: a first optical path component and a second optical path component, the first optical path component is used to homogenize the laser beam emitted by the laser; and the second optical path component
  • the laser wavelength measurement optical path is formed with the first optical path component, which is used to perform hierarchical imaging of the laser beam after the first optical path component is homogenized.
  • the second optical path component includes: an FP etalon component and an optical classifier, which are homogenized The processed laser beam passes through the FP etalon assembly to generate interference fringes; and an optical classifier is arranged after the FP etalon assembly in the laser wavelength measurement optical path, and is used to deflection processing the laser beam passing through the FP etalon assembly, To achieve hierarchical imaging.
  • the FP etalon assembly of the present disclosure enables two FP etalons to share the same optical path for interference imaging, with compact structure, small size, simple design, and high stability; with the cooperation of an optical classifier, accurate measurement of laser wavelength can be achieved simultaneously, The wavelength measurement range is large, which is suitable for online measurement of laser wavelength and corresponding closed-loop control feedback.

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Abstract

一种激光器波长测量装置（2）及方法，激光器波长测量装置（2）包括：第一光路组件和第二光路组件；第一光路组件和第二光路组件构成激光波长测量光路，其中，第二光路组件包括：FP标准具组件（11）和光学分级器（13），经过匀化处理后的激光光束经过FP标准具组件（11）产生干涉条纹；光学分级器（13）在激光波长测量光路中设置于FP标准具组件（11）之后，用于对经过FP标准具组件（11）的激光光束进行偏折处理。FP标准具组件（11）使得两个FP标准具（FP1、FP2）共用同一光路进行干涉成像，结构紧凑体积小，设计简单，稳定性高；在光学分级器（13）的配合下，可以同时实现对激光波长的精准测量，波长测量范围大，适用于激光波长的在线测量以及对应的闭环控制反馈。

Description

激光器波长测量装置及方法 技术领域
本公开涉及激光光谱测量技术领域，具体涉及一种激光器波长测量装置及方法。
背景技术
激光器是现代工业中重要的光源设备，可以用于照明、激光加工、投影显示、光通信、物质分析、测试计量、半导体加工等领域，其中在一些高端领域(如在测试计量和半导体加工等领域)，要求激光具有很高的波长稳定性。因此，这就要求在激光器需要设计对应的激光器波长测量装置，根据测量结果对激光器的波长实现闭环反馈，以确保激光器稳定的波长输出。
在半导体加工技术领域中，准分子激光器是应用于半导体光刻工艺中的主要光源。例如，ArF准分子激光器的中心波长在193.4nm，KrF准分子激光器的中心波长在248.3nm。激光器中心波长的变化直接影响光刻机曝光焦平面的变化，其会引起曝光线条变宽，导致芯片的良品率降低。另外，对于110nm工艺节点，要求激光器的中心波长稳定性高于0.05pm，而对于28nm工艺节点，要求激光器的中心波长稳定性高于0.03pm。
因此，需要对激光器的波长测量设计一种具有pm级的波长测量装置。通过波长测量装置实时测量激光器的波长，并进行闭环控制，从而实现激光器波长的稳定性输出。
激光器激光波长的测量方法有很多，例如色散法和干涉法，色散法包括棱镜色散和光栅色散，干涉法包括傅里叶变换法和Fabry-Perot标准具(以下简称FP标准具)法：
基于棱镜色散和低阶闪耀光栅的方法测量波长的精度低，无法实现高精度的波长测量。另外，基于傅里叶变换法的波长测量，需要有元件的机械运动，稳定性差，无法实现高速波长测量。
现有用于高速、高精度激光器波长测量方法主要包括中阶梯光栅法和FP标准具法。采用中阶梯光栅测量激光器中心波长，中阶梯光栅衍射级次高，可以实现高精度的中心波长测量。然而，中阶梯光栅波长计体积庞 大，不适合用于激光器波长的在线测量，一般用于离线测量。而FP标准具法，因为体积比较小，光谱分辨率高，是激光器在线测量波长的理想选择。通过FP标准具法，激光在经过FP标准具后，产生干涉条纹，根据干涉条纹峰值的位置，得到入射激光器的波长。
但是，现有FP标准具测量波长的范围比较小，一般无法通过一个FP标准具实现大范围和高精度的波长测量。例如，采用FP标准具和光栅联合的方式测量波长，将入射激光分为两束，分别照射到光栅和FP标准具上，其中光栅用于波长的粗测，FP标准具用于波长的精测，从而得到激光器的波长的精确值。
另外，还可以采用两个FP标准具测量激光器波长，其中一路FP标准具测量范围比较大，用于中心波长的粗测，另一路FP标准具测量范围比较小，用于中心波长的精测。采用分束镜将激光器的激光光束分为两束，分别照射到两个FP标准具上，然后计算两个FP标准具干涉条纹，得到波长粗测和精测结果，从而得到激光器波长的精确值。
之外，还可以采用了两个串联的FP标准具对波长进行测量，一个FP标准具粗略确定波长偏差，另一个FP标准具精确确定波长偏差，通过对比两个FP标准具之后干涉信号的强度，得到激光器的波长偏差，从而维持激光器波长稳定。
或者，采用两个并行的FP标准具和一个光栅作为干涉型滤波片对入射激光器的强度进行检测，每个滤光片的波长测量精度不同，逐级测量出激光器的波长，得到激光器波长的精确值。
基于上述激光器波长测量的方法，采用至少两套波长测量装置，一个(或多个)用于波长粗测，一个采用FP标准具法用于波长精测，需要对入射激光进行分束，两套波长测量装置无法做到完全共光路，装置比较复杂。最终的波长测量结果只取决于一路FP标准具精测的结果，容易受到外界环境的影响，波长测量精度和稳定性比较差。
发明内容
本公开的一个方面公开了一种激光器波长测量装置，包括：第一光路组件和第二光路组件，第一光路组件用于对激光器出射的激光光束进行匀化处理；以及第二光路组件与第一光路组件构成激光波长测量光路，用于 对经过第一光路组件匀化处理之后的激光光束进行分级成像，其中，第二光路组件包括：FP标准具组件和光学分级器，经过匀化处理后的所述激光光束经过FP标准具组件产生干涉条纹；以及光学分级器在激光波长测量光路中设置于FP标准具组件之后，用于对经过FP标准具组件的激光光束进行偏折处理，以实现分级成像。
根据本公开的实施例，其中，第一光路组件包括：沿激光波长测量光路依次设置的分束镜和匀光组件；其中，分束镜用于将激光器出射的一部分激光光束反射至激光波长测量光路；匀光组件用于对被分束镜反射至所述激光波长测量光路的激光光束进行匀化处理。
根据本公开的实施例，其中，匀光组件包括：沿激光波长测量光路依次设置的光学匀光元件、第一会聚镜和反射镜；其中，光学匀光元件用于对激光光束进行匀化，以减小激光光束质量对测量精度的影响；第一会聚镜用于将光学匀光元件匀化处理后的激光光束会聚至第二光路组件中；反射镜用于将第一会聚镜会聚后的激光光束反射至第二光路组件中。
根据本公开的实施例，其中，第二光路组件还包括：沿激光波长测量光路依次设置的匀光片、视场光阑以及准直镜，其中，匀光片在激光波长测量光路中对应设置于第一光路组件之后，用于对经过第一光路组件入射至第二光路组件的激光光束作进一步的匀化处理；视场光阑用于控制经过匀光片匀化处理之后的激光光束在分级成像中的成像范围；准直镜在激光波长测量光路中对应设置于FP标准具组件之前，用于保证入射至FP标准具组件的激光光束的准直特性。
根据本公开的实施例，其中，第二光路组件还包括：孔径光阑，在激光波长测量光路中设置于FP标准具组件和光学分级器之间，用于限制经过FP标准具组件的激光光束的走向。
根据本公开的实施例，其中，第二光路组件还包括：沿激光波长测量光路依次设置的第二会聚镜和成像设备，其中，第二会聚镜设置于在激光波长测量光路中设置于光学分级器之后，用于将经过光学分级器的激光光束会聚至成像设备中；成像设备用于对经过第二会聚镜的激光光束进行成像。
根据本公开的实施例，其中，FP标准具组件包括：外壳、第一FP标 准具和第二FP标准具，外壳用于构成FP标准具组件的密封腔体；第一FP标准具设置于密封腔体内，用于对应产生分级成像的第一干涉条纹；第二FP标准具对应于第一FP标准具设置于密封腔体内，用于对应产生分级成像的第二干涉条纹。
根据本公开的实施例，其中，第一FP标准具和第二FP标准具满足：
Figure PCTCN2020135615-appb-000001
其中，k＜0.2，FSR 1为第一FP标准具的自由光谱程，FSR 2为第二FP标准具的自由光谱程。
根据本公开的实施例，其中，外壳包括：第一密封槽、第一密封圈和第一窗口件，以及第二密封槽、第二密封圈和第二窗口件，第一密封槽对应于外壳的进光口设置；第一密封圈匹配于第一密封槽设置于进光口上；第一窗口件匹配于第一密封圈设置于第一密封槽内；以及第二密封槽对应于外壳的出光口设置；第二密封圈匹配于第二密封槽设置于出光口上；第二窗口件匹配于第二密封圈设置于第二密封槽内；其中，第一窗口件和第二窗口件上均具有减反膜，或者第一窗口件的进光面的法线和/或出光面的法线与激光光束的入射方向呈第一夹角，和/或第二窗口件的进光面的法线和/或出光面的法线与激光光束的入射方向呈第二夹角，第一夹角或第二夹角为5度-10度。
根据本公开的实施例，其中，光学分级器包括：第一偏折件和第二偏折件，第一偏折件具有第一楔角，用于对经过第一FP标准具的激光光束进行偏折处理；第二偏折件具有第二楔角，通过第二楔角与第一偏折件的第一楔角对应设置，用于对经过第二FP标准具的激光光束进行偏折处理。
根据本公开的实施例，其中，光学分级器包括：第三偏折件，具有第三楔角，用于对经过第一FP标准具的激光光束进行偏折处理，或对经过第二FP标准具的激光光束进行偏折处理。
根据本公开的实施例，其中，光学分级器包括：第四偏折件，包括：透光孔，平行于激光光束进光方向穿设于第四偏折件上；其中，当第四偏折件对经过第一FP标准具的激光光束进行偏折处理时，透光孔用于使得 经过第二FP标准具的激光光束穿过透光孔；当第四偏折件对经过第二FP标准具的激光光束进行偏折处理时，透光孔用于使得经过第一FP标准具的激光光束穿过透光孔。
本公开的另一个方面公开了一种激光器波长测量系统，包括：上述的激光器波长测量装置和激光器，激光器用于产生入射至激光器波长测量装置的激光光束。
本公开的又一个方面公开了一种激光器波长测量方法，应用于上述的激光器波长测量装置，实现对激光器的激光波长的测量。
附图说明
图1A是本公开一实施例中的激光器波长测量装置的结构组成示意图；
图1B是本公开另一实施例中的激光器波长测量装置的结构组成示意图；
图2是本公开实施例中的激光器波长测量装置的FP标准具组件和一光学分级器的结构组成示意图；
图3是本公开实施例中的激光器波长测量装置的另一光学分级器的结构组成示意图；
图4是本公开实施例中的激光器波长测量装置的又一光学分级器的结构组成示意图；
图5是本公开实施例中的激光器波长测量装置的对应图2所示的FP标准具组件和光学分级器对应的激光光束干涉条纹在CCD成像设备上的成像结果；
图6是本公开实施例中的对应激光器波长测量装置的激光器的激光波长对应其干涉条纹的分布示意图。
具体实施方式
为使本公开的目的、技术方案和优点更加清楚明白，以下结合具体实施例，并参照附图，对本公开进一步详细说明。
为解决现有技术中激光器波长测量装置无法做到完全共光路，装置比较复杂，以及波长测量结果容易受到外界影响导致波长测量精度和稳定性比较差的技术问题，本公开公开了一种激光器波长测量装置及方法。
本公开的一个方面公开了一种激光器波长测量装置，如图1A、图1B 所示，激光器波长测量装置2包括：第一光路组件和第二光路组件，第一光路组件用于对激光器1出射的激光光束进行匀化处理；以及第二光路组件对应于第一光路组件设置，与第一光路组件构成激光波长测量光路，第二光路组件用于对经过第一光路组件匀化处理之后的激光光束进行分级成像。由激光器1产生的待测激光光束入射至第一光路组件之后，沿上述激光波长测量光路经过第一光路组件入射至第二光路组件，并在第二光路组件中进行分级成像，获得测量结果，例如对应激光光束的干涉条纹。
根据本公开的实施例，第二光路组件包括：FP标准具组件11和光学分级器13，FP标准具组件11用于对应激光光束产生干涉条纹；具体地，经过FP标准具组件11的激光光束照射至成像设备15上之后，被成像设备15检测并据此获取其对应的干涉条纹，即经过匀化处理后的所述激光光束经过FP标准具组件后产生干涉条纹。其中，FP标准具组件11中可以包括多个FP标准具，例如可以存在两个FP标准具密封在FP标准具组件的同一腔体内，因此实现了至少两个FP标准具共用同一光路进行干涉成像，使得光路结构紧凑，稳定性更高。同时，在至少两个FP标准具的FP标准具组件设计中，由于FP标准具之间的自由光谱程FSR比较接近，均可以实现对激光光束的波长进行精确测量。波长测量结果可以是至少两个FP标准具的测量结果的平均值，进一步提高了波长测量精度，同时波长测量范围还可以是至少两个FP标准具自由光谱程FSR的乘积，进一步提高了波长的测量范围。
另外，光学分级器13在激光波长测量光路中对应设置于FP标准具组件11之后，用于对经过FP标准具组件11的激光光束进行偏折处理，以实现分级成像。激光光束沿上述激光波长测量光路经过FP标准具组件11入射至光学分级器13，光学分级器13可以将激光光束偏折为两束，使得对应激光光束的干涉条纹在成像设备15上分开成像，从而助于通过计算两个干涉条纹的强度位置，获得入射激光光束的波长。
因此，本公开的FP标准具组件11使得至少两个FP标准具共用同一光路进行干涉成像，结构紧凑体积小，设计简单，稳定性高；在光学分级器13的配合下，可以同时实现对激光器的激光波长的精准测量，波长测量范围大，适用于激光波长的在线测量以及对应的闭环控制反馈。
根据本公开的实施例，其中，如图1A、图1B所示，第一光路组件包括：沿激光波长测量光路依次设置的分束镜3和匀光组件4；其中，激光器1产生待测激光光束，入射至激光器波长测量装置2。具体地，待测激光光束入射至第一光路组件中。在第一光路组件中，待测激光光束照射至分束镜3上，分束镜3为一平板玻璃或带楔角的玻璃，用于将大部分光透过该分束镜3，同时还用于将该激光器出射的一部分激光光束反射至激光波长测量光路，即使得部分待测激光光束经反射入射至第一光路组件中的匀光组件中。匀光组件4在激光波长测量光路中对应设置于分束镜3之后，用于对被分束镜3反射至所述激光波长测量光路的激光光束进行匀化处理。
根据本公开的实施例，其中，如图1A、图1B所示，匀光组件4包括：沿激光波长测量光路依次设置的光学匀光元件5、第一会聚镜6和反射镜7.其中，光学匀光元件5用于对激光光束进行匀化，以减小激光光束质量对测量精度的影响，该光学匀光元件5可以是微透镜阵列、光学积分棒或衍射光学元件(DOE)等元件。第一会聚镜6用于将光学匀光元件5匀化处理后的激光光束会聚至第二光路组件中。其中，在第二光路组件和第一会聚镜6之间还可以设置一反射镜7，该反射镜7用于将第一会聚镜6会聚后的激光光束反射至第二光路组件中，该反射镜7可以在反光面上镀设一层高反膜，用于增强反射激光光束的能力。通过反射镜7可以改变激光波长测量光路的路径，使得激光器波长测量装置2的结构更加紧凑，有实现缩小该激光器波长测量装置2的体积。
根据本公开的实施例，其中，如图1A、图1B所示，第二光路组件还包括：沿激光波长测量光路依次设置的匀光片8、视场光阑9以及准直镜10，其中，经过第一会聚镜6会聚后，经过第一光路组件的反射镜7的反射的激光光束反射至第二光路组件中的匀光片8上，匀光片8在激光波长测量光路中对应设置于第一光路组件的反射镜7之后，用于对经过第一光路组件入射至第二光路组件的激光光束作进一步的匀化处理，该匀光片8可以是毛玻璃或其他具有匀光效果的元件。视场光阑9用于控制经过匀光片8进一步的匀化处理之后的激光光束在分级成像中的成像范围，即控制干涉条纹在成像设备15的成像面上的成像范围。准直镜10在激光波长测量光路中对应设置于FP标准具组件11之前，用于保证入射至FP标准具 组件11的激光光束的准直特性，并使得依次经过匀光片8、视场光阑9的激光光束经过准直镜10入射至到FP标准具组件11。
根据本公开的实施例，其中，如图1A、图1B所示，第二光路组件还包括：孔径光阑12，在激光波长测量光路中设置于FP标准具组件11和光学分级器13之间，用于限制经过FP标准具组件11的激光光束的走向。在本公开实施例的FP标准具组件11中可以存在至少两个FP标准具(FP1和FP2)，经过两个FP标准具的激光光束经过孔径光阑12，可以防止两条激光光束交叉。
本领域技术人员应当予以理解，FP标准具组件11中的该至少两个FP标准具也可以包括三个FP标准具，或者更多。具体地，如图1B所示，FP标准具组件11中包括3个FP标准具(FP1、FP2和FP3)。
根据本公开的实施例，其中，如图1A、图1B所示，第二光路组件还包括：沿激光波长测量光路依次设置的第二会聚镜14和成像设备15，其中，第二会聚镜14设置于在激光波长测量光路中设置于光学分级器13之后，用于将经过光学分级器13的激光光束会聚至成像设备15中；成像设备15用于对经过第二会聚镜14的激光光束进行成像，成像设备15可以是CCD成像相机。具体地，激光光束在经过孔径光阑12后入射至光学分级器13上，光学分级器13将对应不同入射位置的光束偏折为不同的出射角度，再入射至第二会聚镜14上，最后经过第二会聚镜14的会聚作用，两条激光光束在不相互影响的情况下入射至成像设备15中完成成像。因为光学分级器13的存在，将经过FP标准具FP1和FP标准具FP2的光偏折了不同的角度，所以FP标准具FP1和FP标准具FP2的干涉条纹可以成像在成像设备15的不同位置，选择合适的偏转角度，可以在成像设备15上得到不同的干涉条纹。如图5所示，为在CCD成像相机上获得的FP标准具FP1和FP标准具FP2的干涉条纹，其中左侧为FP1的干涉条纹，右侧为FP2的干涉条纹。
根据本公开的实施例，其中，如图1A、图1B、图2所示，FP标准具组件11包括：外壳16、第一FP标准具FP1和第二FP标准具FP2，即在本公开的实施例中，激光器波长测量装置2的FP标准具组件中可以设计为两个FP标准具。
本领域技术人员应当予以理解，如图1B所示，FP标准具组件11中还可以包括第三FP标准具FP3，设置于第一FP标准具FP1和第二FP标准具FP2之间。
外壳16用于构成FP标准具组件11的密封腔体，密封腔体用于密封内置其中的第一FP标准具FP1和第二FP标准具FP2。第一FP标准具FP1设置于密封腔体内，用于对应在成像设备15上产生分级成像的第一干涉条纹；第二FP标准具FP2对应于第一FP标准具FP1设置于密封腔体内，用于对应产生分级成像的第二干涉条纹。如图2所示，第一FP标准具FP1设置于密封腔体的上方，第二FP标准具FP2对应设置于第一FP标准具FP1的下方，第一FP标准具FP1与第二FP标准具FP2可以满足：
Figure PCTCN2020135615-appb-000002
其中，k＜0.2，FSR 1为第一FP标准具FP1的自由光谱程，FSR2为第二FP标准具FP2的自由光谱程。换言之，第一FP标准具FP1的自由光谱程FSR 1和第二FP标准具FP2的自由光谱程FSR2相近。在本公开的实施例中，在半导体加工技术领域中，应用于光刻工艺的准分子激光器波长变化范围通常为几百pm，为了保证激器光波长测量的测量精度和测量范围，可以取FSR 1＝20pm，FSR 2＝20.5pm。本领域技术人员应当理解，上述关参数FSR 1和FSR 2的数值只是本公开实施例的一具体实施数据，并非是对该参数数据的具体限制。另一方面，如图6所示，当激光器的波长发生变化时，FP标准具对应激光器产生的激光光束的干涉条纹的分布也会产生相应变化，借此，当其中一个FP标准具(例如第一FP标准具FP1)达到一个自由光谱程FSR 1后，因为第二FP标准具FP2的自由光谱程FSR2与第一FP标准具FP1的自由光谱程FSR 1略有不同，使得二者所对应产生的干涉条纹不会发生重复，因此扩大了本公开的激光器波长测量装置2的波长测量范围，波长测量范围至少可以实现410pm(即二者乘积FSR 1×FSR 2)，使其满足了准分子激光器波长测量需求。同时，两个FP标准具使得激光器波长测量装置2兼具高光谱分辨率。
至此，以上述的准分子激光器为例，以对本公开实施例中激光器波长 测量装置2的波长测量予以进一步说明，如下：
对于FP标准具，激光器入射到激光波长测量光路的激光光束波长(即待测激光器的中心波长λ)满足如下公式(1)：
Figure PCTCN2020135615-appb-000003
其中，λ为激光器的中心波长，n为FP标准具内气体的折射率，d为FP标准具的间距，m为FP标准具干涉条纹的级次，θ为FP标准具对应的激光光束的出射角。
设FP标准具干涉条纹的半径为r，第二会聚镜14的焦距为f时，根据上述FP标准具对应的干涉条纹的半径r即可得到该FP标准具测得的激光器的中心波长λ满足如下公式(2)：
Figure PCTCN2020135615-appb-000004
相应地，在本公开的实施例中，当第一FP标准具FP1的间距为d 1，第二FP标准具FP2间距为d 2时，各自对应的干涉条纹(如图5所示)的半径分别为r 1和r 2，则其对应的激光器的中心波长分别满足如下公式(3)和(4)：
Figure PCTCN2020135615-appb-000005
Figure PCTCN2020135615-appb-000006
另外，根据第一FP标准具FP1的间距d 1，第二FP标准具FP2间距d 2，可以得到第一FP标准具FP1和第二FP标准具FP2的自由光谱程分别满足如下公式(5)和(6)：
Figure PCTCN2020135615-appb-000007
Figure PCTCN2020135615-appb-000008
分别计算第一FP标准具FP1和第二FP标准具FP2的干涉条纹，可以得到激光器的中心波长各自满足如下公式(7)和(8)：
λ FP1＝λ 1+N·FSR 1
λ FP2＝λ 2+M·FSR 2
其中，N和M为整数，在一定范围内可以选取不同的整数N和M，使λ FP1-λ FP2最小，此时得到激光器的中心波长λ laser为：
Figure PCTCN2020135615-appb-000009
可以看出，测得激光器的中心波长λ laser为两个FP标准具(即第一FP标准具FP1和第二FP标准具FP2)各自精测波长的平均值，其稳定性高于单独一个FP标准具的测量结果，同时还实现了波长测量范围。
需要提醒的是，如果为三个FP标准具，如图1B所示，则FP标准具组件11中三个FP标准具的自由光谱程也要求相近，第三标准具FP3标准具所精测的波长的过程与第一FP标准具FP1、第二FP标准具FP2相同，此时激光器的中心波长则为三个PF标准具各自精测波长的平均值，从而可以进一步提高激光器中心波长的测量精度。同理，对于其他FP标准具组件11中具有更多个FP标准具的情况，也一并适用，在此不作赘述。
根据本公开的实施例，其中，如图1A、图1B和图2所示，FP标准组件11的外壳16包括：第一密封槽、第一密封圈18a和第一窗口件17a，以及第二密封槽、第二密封圈18b和第二窗口件17b，用于确保对该外壳16的密封腔体实现较好的密封效果。
第一密封槽对应于外壳16的进光口设置，如图2所示光路箭头，外壳16左侧对应于第一窗口件17a的透光口为进光口，第一密封槽可以是围绕该进光口的边缘内凹于外壳16设计的环形闭合密封槽结构。其中， 如图2所示，第一密封圈包括第一固定槽和第一主体槽，分别用于对应设置第一密封圈18a和第一窗口件17a。
第一密封圈18a匹配于第一密封槽设置于进光口上，具体地，第一密封圈18a内置于第一固定槽中，第一密封圈18a为围绕该进光口的边缘设计的环形闭合实体结构，其形状和尺寸与上述的第一固定槽的形状尺寸匹配设计，用于将第一密封圈18a恰好装设于第一固定槽内。
第一窗口件17a匹配于第一密封圈18a设置于第一密封槽内；具体地，第一窗口件17a内置于第一主体槽中，第一窗口件17a与第一主体槽的尺寸、形状匹配设计，使得第一窗口件17a恰好装设于第一主体槽内，以配合第一密封圈18a将进光口密封完好。
第二密封槽对应于外壳16的出光口设置；如图2所示光路箭头，外壳16右侧对应于第二窗口件17b的透光口为出光口，第二密封槽可以是围绕该出光口的边缘内凹于外壳16设计的环形闭合密封槽结构。其中，如图2所示，第二密封圈包括第二固定槽和第二主体槽，分别用于对应设置第二密封圈18b和第一窗口件17b。
第二密封圈18b匹配于第二密封槽设置于出光口上；具体地，第二密封圈18b内置于第二固定槽中，第二密封圈18b为围绕该出光口的边缘设计的环形闭合实体结构，其形状和尺寸与上述的第二固定槽的形状尺寸匹配设计，用于将第二密封圈18b恰好装设于第二固定槽内。
第二窗口件17b匹配于第二密封圈18b设置于第二密封槽内；具体地，第二窗口件17b内置于第二主体槽中，第二窗口件17b与第二主体槽的尺寸、形状匹配设计，使得第二窗口件17b恰好装设于第二主体槽内，以配合第二密封圈18b将出光口密封完好。
其中，第一密封圈18a和第二密封圈18b均可以采用橡胶、硅胶等具有弹性形变性能的材料。第一窗口件17a和第二窗口件17b均可以采用玻璃等具有透光性能的材料。另外，第一窗口件17a和第二窗口件17b上均具有减反膜，和/或第一窗口件17a的进光面的法线和/或出光面的法线与激光光束的入射方向呈第一夹角，和/或第二窗口件17b的进光面的法线和/或出光面的法线与激光光束的入射方向呈第二夹角，第一夹角或第二夹角为5度-10度，以减小第一窗口件17a和第二窗口件17b上反射光对激光 器波长测量结果的影响。换言之，激光光束不可以以垂直角度入射至第一窗口件17a和/或第二窗口件17b的进光面和/或出光面。因此，第一窗口件17ah和/或第二窗口件17b可以为具有楔角的结构；或者，第一窗口件17a以斜向角度摆设在进光口并将其密封，和/或第二窗口件17b以一定斜向角度摆设在出光口并将其密封。
本领域技术人员应当可以理解，当测量光路的FP标准具组件11中有多个FP标准具时，如图1B所示3个FP标准具，则多个FP标准具的密封方式与两个FP标准具的密封方式相同，即都密封在同一密封腔内，在此不作赘述。
根据本公开的一实施例，当第一窗口件17a和第二窗口件17b为具有楔角的结构时，入射激光光束入射方向与第一窗口件17a的进光面和出光面无法垂直，第一窗口件17a的进光面的法线或出光面的法线与激光光束的入射方向呈第一夹角，第一夹角为5度-10度；同理，第二窗口件17b的进光面的法线或出光面的法线与激光光束的入射方向呈第二夹角，第二夹角为5度-10度。
根据本公开的另一实施例，第一窗口件17a也可以不具有楔角的结构，例如可以为平板玻璃，斜向安装至外壳16的进光口，激光光束的入射方向与第一窗口件17a的进光面的法线和出光面的法线分别呈5-10度的夹角，即使得入射激光光束入射方向与第一窗口件17a的进光面和/或出光面无法垂直；同理，第二窗口件17b可以斜向安装至外壳16的出光口，具体不再赘述。其中，在本公开的实施例中，进光面为光学元件上光线照射至的表面，出光面为光学元件上自其出射的表面，一般可以是进光面的背表面。
借此，可以确保第一FP标准具FP1和第二FP标准具FP2处于同一密封环境中，以保证激光器波长测量的稳定性和精度。
根据本公开的实施例，其中，如图1A、图1B和图2所示，光学分级器13包括：第一偏折件19a和第二偏折件19b，用于对经过光学分级器13的激光光束进行偏折处理。其中，第一偏折件19a具有第一楔角，用于对经过第一FP标准具FP1的激光光束进行偏折处理；第一偏折件19a的进光面垂直于经过第一FP标准具FP1的激光光束的入射方向，第一偏折 件19a的出光面为一斜面，使得该第一偏折件19a的出光面和进光面之间具有对应第一楔角的夹角，该第一楔角可以对应于第一偏折件19a的顶端设置。
对应地，第二偏折件19b具有第二楔角，通过第二楔角与第一偏折件19a的第一楔角对应设置，用于对经过第二FP标准具FP2的激光光束进行偏折处理。第二偏折件19b的进光面垂直于经过第二FP标准具FP2的激光光束的入射方向，第二偏折件19b的出光面为一斜面，使得该第二偏折件19b的出光面和进光面之间具有对应第二楔角的夹角。其中，第一楔角可以等于第二楔角，该第二楔角可以对应于第二偏折件19b的顶端设置。
在本公开的实施例中，为使得经过第一偏折件19a被其偏折处理的激光光束，与经过第二偏折件19b被其偏折处理的激光光束不发生交叉，第一偏折件19a和第二偏折件19b需要顶端相对设置，即第一偏折件19a具有第一楔角的顶端和第二偏折件19b具有第二楔角的顶端相接触，第一偏折件19a和第二偏折件19b的进光面在垂直于进光方向上持平。
在本公开的另一实施例中，第一偏折件19a的进光面也可以不垂直于经过第一FP标准具FP1的激光光束的入射方向，同理，第二偏折件19b的进光面也可以不垂直于经过第一FP标准具FP1的激光光束的入射方向。此时，第一偏折件19a和第二偏折件19b还可以以顶端相对设置。
因此，经过FP标准具组件的激光光束在通过孔径光阑12之后，其形成的空间位置发生变化，分为两条激光光束入射至光学分级器13上，光学分级器13采用第一偏折件19a和第二偏折件19b分别对两条光束进行偏折，改变其各自的出射角度，使其出射方向产生不同，从而使得其入射至成像设备15(例如CCD成像相机)上时，成像设备15能够获得对应各自激光光束的不同位置的干涉条纹。
需要进一步说明的是，如图1B所示，FP标准具组件11中具有三个FP标准具的情况，第三FP标准具FP3设置于第一FP标准具FP1和第二FP标准具FP2之间，且第三FP标准具FP3的中心光轴线与第二会聚镜14中心光轴线对应重合时，则光学分级器13中对应第三FP标准具FP3的位置，可以不再对应设置偏折件，也即如图1B所示，通过第三FP标准具FP3的光束可以直接向第二会聚镜14中心垂直入射，经过第二会聚镜 14后直接入射至成像设备15。因此，本领域技术人员应当可以理解，对于FP标准具组件11中具有更多数量的FP标准具而言，也可以相应获得其光路路径和对应的偏折件的数量和设置位置等，在此不作赘述。
根据本公开的另一实施例，其中，如图1A、图1B、图3所示，光学分级器13还包括：第三偏折件21，具有第三楔角，用于对经过第一FP标准具FP1的激光光束G1进行偏折处理，或对经过第二FP标准具FP2的激光光束G2进行偏折处理。同样地，第三偏折件21的进光面垂直于激光光束G1(或激光光束G2)的入射方向，第三偏折件21的出光面为一斜面，使得该第三偏折件21的出光面和进光面之间具有对应第三楔角的夹角。此时，该光学分级器13中仅仅具有使得入射至该第三偏折件21的激光光束G1(或激光光束G2)发生偏折的作用，对于另一未入射至第三偏折件21的激光光束G2(或激光光束G1)而言，可以直接发生无偏折角度的出射，最后入射至成像设备15进行成像。
换言之，该光学分级器13可以只设计一个第三偏折件21，即可以实现对入射经过的两条激光光束实现偏折，使其出射方向产生不同，从而使得其入射至成像设备15(例如CCD成像相机)上时，成像设备15能够获得对应各自激光光束的不同位置的干涉条纹。其中，该第三偏折件21只占据原光学分级器13的上端部分空间或下端部分空间，体积尺寸较小，有实现光学分级器13的尺寸缩小，以助于本公开的激光测量装置尺寸的缩小。
根据本公开的又一实施例，其中，如图1A、图1B、图4所示，光学分级器13包括：第四偏折件22，第四偏折件22包括：透光孔23，平行于激光光束进光方向穿设于第四偏折件22上，具体地，第四偏折件22具有第四楔角，用于对经过第一FP标准具FP1的激光光束G1进行偏折处理，或对经过第二FP标准具FP2的激光光束G2进行偏折处理。同样地，第四偏折件22的进光面垂直于激光光束G1(或激光光束G2)的入射方向，第第四偏折件22的出光面为一斜面，使得该第四偏折件22的出光面和进光面之间具有对应第四楔角的夹角。其中，可以在第四偏折件22上靠近第四楔角所在的顶端部位穿设透光孔23，使得其与第四偏折件22的主体部分间隔一定距离，避免相互影响。
因此，当第四偏折件22对经过激光光束G1进行偏折处理时，透光孔23用于使得激光光束G2穿过透光孔23；当第四偏折件对激光光束G2进行偏折处理时，透光孔用于使得激光光束G1穿过透光孔23。
可见，该光学分级器13也可以只设计一个第四偏折件22，即可以实现对入射经过的两条激光光束实现偏折，使其出射方向产生不同，达到与第三偏折件21类似的技术效果。其中，该第四偏折件22可以占据光学分级器13的大部分空间，其体积尺寸可以保证加工制作的便利性。
最后，本领域技术人员应当理解，上述实施例中对光学分级器13的解释，并非是对其的限定。其中，如图1A、图1B、图2、图3和图4所示，第一偏折件19a、第二偏折件19b、第三偏折件21、第四偏折件22等可以为偏折棱镜，也可以为反射镜、摆镜或微振镜等具有激光光束偏折效果的元件或结构。
本公开的另一个方面公开了一种激光器波长测量系统，如图1A、图1B所示，包括：上述的激光器波长测量装置2和激光器1，激光器1用于产生入射至激光器波长测量装置2的待测激光光束，通过该激光器波长测量装置2获取对应待测激光光束的中心波长。其中，该激光器1和激光器波长测量装置2之间具有在线测量和闭环控制反馈的设计。
本公开的又一个方面公开了一种激光器波长测量方法，应用于上述的激光器波长测量装置2，根据前文所提及的激光器波长测量运算过程，实现对激光器1的激光光束的中心波长的测量。
本公开一种激光器波长测量装置及方法，该激光器波长测量装置包括：第一光路组件和第二光路组件，第一光路组件用于对激光器出射的激光光束进行匀化处理；以及第二光路组件与第一光路组件构成激光波长测量光路，用于对经过第一光路组件匀化处理之后的激光光束进行分级成像，其中，第二光路组件包括：FP标准具组件和光学分级器，经过匀化处理后的所述激光光束经过FP标准具组件产生干涉条纹；以及光学分级器在激光波长测量光路中设置于FP标准具组件之后，用于对经过FP标准具组件的激光光束进行偏折处理，以实现分级成像。本公开的FP标准具组件使得两个FP标准具共用同一光路进行干涉成像，结构紧凑体积小，设计简单，稳定性高；在光学分级器的配合下，可以同时实现对激光波长的精准 测量，波长测量范围大，适用于激光波长的在线测量以及对应的闭环控制反馈。
以上所述的具体实施例，对本发明的目的、技术方案和有益效果进行了进一步详细说明，应理解的是，以上所述仅为本发明的具体实施例而已，并不用于限制本发明，凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种激光器波长测量装置，其中，包括：
    第一光路组件，用于对激光器出射的激光光束进行匀化处理；以及
    第二光路组件，与所述第一光路组件构成激光波长测量光路，用于对经过所述第一光路组件匀化处理后的激光光束进行分级成像；
    其中，所述第二光路组件包括：
    FP标准具组件，所述FP标准具组件包括至少两个FP标准具，匀化处理后的所述激光光束经过所述FP标准具组件产生干涉条纹；以及
    光学分级器，在所述激光波长测量光路中设置于所述FP标准具组件之后，用于对经过所述FP标准具组件的激光光束进行偏折处理，以实现分级成像。
  2. 根据权利要求1所述的激光器波长测量装置，其中，所述第一光路组件包括：沿所述激光波长测量光路依次设置的分束镜和匀光组件；其中：
    所述分束镜，用于将激光器出射的一部分激光光束反射至所述激光波长测量光路；
    所述匀光组件，用于对被所述分束镜反射至所述激光波长测量光路的激光光束进行匀化处理；所述匀光组件包括：沿所述激光波长测量光路依次设置的光学匀光元件、第一会聚镜和反射镜；其中：
    所述光学匀光元件，用于对所述激光光束进行匀化，以减小所述激光光束质量对测量精度的影响；
    第一会聚镜，用于将所述光学匀光元件匀化处理后的激光光束会聚至所述第二光路组件中；
    反射镜，用于将所述第一会聚镜会聚后的激光光束反射至所述第二光路组件中。
  3. 根据权利要求1所述的激光器波长测量装置，其中，所述第二光路组件还包括：沿所述激光波长测量光路依次设置的匀光片、视场光阑、准直镜、第二会聚镜以及成像设备，其中，
    所述匀光片在所述激光波长测量光路中对应设置于所述第一光路组件之后，用于对经过所述第一光路组件入射至所述第二光路组件的激光光束作进一步的匀化处理；
    所述视场光阑用于控制经过所述匀光片匀化处理之后的激光光束在所述分级成像中的成像范围；
    所述准直镜在所述激光波长测量光路中对应设置于所述FP标准具组件之前，用于保证入射至所述FP标准具组件的激光光束的准直特性；
    所述第二会聚镜，在所述激光波长测量光路中设置于所述光学分级器之后，用于将经过所述光学分级器的激光光束会聚至所述成像设备中；
    所述成像设备，用于对经过所述第二会聚镜的激光光束进行成像。
  4. 根据权利要求1所述的激光器波长测量装置，其中，所述第二光路组件还包括：
    孔径光阑，在所述激光波长测量光路中设置于所述FP标准具组件和所述光学分级器之间，用于限制经过所述FP标准具组件的激光光束的走向。
  5. 根据权利要求1所述的激光器波长测量装置，其中，所述FP标准具组件包括：
    外壳，用于构成所述FP标准具组件的密封腔体；
    第一FP标准具，设置于所述密封腔体内，用于对应产生所述分级成像的第一干涉条纹；
    第二FP标准具，对应于所述第一FP标准具设置于所述密封腔体内，用于对应产生所述分级成像的第二干涉条纹。
  6. 根据权利要求5所述的激光器波长测量装置，其中，所述第一FP标准具和所述第二FP标准具满足：
    Figure PCTCN2020135615-appb-100001
    其中，k＜0.2，FSR 1为第一FP标准具的自由光谱程，FSR 2为第二FP标准具的自由光谱程。
  7. 根据权利要求5所述的激光器波长测量装置，其中，所述外壳包括：
    第一密封槽，对应于所述外壳的进光口设置；
    第一密封圈，匹配于所述第一密封槽设置于所述进光口上；
    第一窗口件，匹配于所述第一密封圈设置于所述第一密封槽内；以及
    第二密封槽，对应于所述外壳的出光口设置；
    第二密封圈，匹配于所述第二密封槽设置于所述出光口上；
    第二窗口件，匹配于所述第二密封圈设置于所述第二密封槽内；
    其中，所述第一窗口件和所述第二窗口件上均具有减反膜，或者
    所述第一窗口件的进光面的法线和/或出光面的法线与所述激光光束的入射方向呈第一夹角，和/或
    所述第二窗口件的进光面的法线和/或出光面的法线与所述激光光束的入射方向呈第二夹角，
    所述第一夹角或第二夹角为5度-10度。
  8. 根据权利要求1所述的激光器波长测量装置，其中，所述光学分级器包括：
    第一偏折件，具有第一楔角，用于对经过所述第一FP标准具的激光光束进行偏折处理；
    第二偏折件，具有第二楔角，通过所述第二楔角与所述第一偏折件的第一楔角对应设置，用于对经过所述第二FP标准具的激光光束进行偏折处理。
  9. 根据权利要求1所述的所述的激光器波长测量装置，其中，所述光学分级器包括：
    第三偏折件，具有第三楔角，用于对经过所述第一FP标准具的激光光束进行偏折处理，或对经过所述第二FP标准具的激光光束进行偏折处理；
    或者
    第四偏折件，所述第四偏折件包括：
    透光孔，平行于激光光束进光方向穿设于所述第四偏折件上；其中，
    当所述第四偏折件对经过所述第一FP标准具的激光光束进行偏折处 理时，所述透光孔用于使得经过所述第二FP标准具的激光光束穿过所述透光孔；
    当所述第四偏折件对经过所述第二FP标准具的激光光束进行偏折处理时，所述透光孔用于使得经过所述第一FP标准具的激光光束穿过所述透光孔。
  10. 一种激光器波长测量方法，应用于权利要求1至9中任一项所述的激光器波长测量装置，实现对激光器产生的激光波长的测量。
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