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CN-122003584-A - Adjustment method, adjustment system, and laser beam apparatus

CN122003584ACN 122003584 ACN122003584 ACN 122003584ACN-122003584-A

Abstract

The invention relates to a method (10) for adjusting a beam focus (12), in particular a focal point position (18), of a laser beam (14) of a laser beam device (22) having an optical arrangement (52), in particular for generating extreme ultraviolet radiation (EUV), comprising the method steps of a) determining (24) three beam diameters (26,32,36,40) of the laser beam (14) at three measuring planes (28,30,34,38) located in a laser beam propagation direction (16), b) determining (42) the beam focus (12) of the laser beam (14) by evaluating beam propagation parameters of the laser beam (14) on the basis of the three determined beam diameters (26,32,36,40), c) determining (46) the laser beam deviation by comparing the beam focus (12) of the laser beam (14) with a target beam focus (48), d) adjusting (50) the laser beam device (22), in particular the optical arrangement (52) as a function of the determined laser beam deviation. The invention also relates to an adjustment system (58) and a laser beam device (22).

Inventors

  • Boltze T.

Assignees

  • 通快激光系统半导体制造欧洲股份公司

Dates

Publication Date
20260508
Application Date
20241010
Priority Date
20231012

Claims (12)

  1. 1. Method (10) for adjusting a beam focus (12), in particular a focal position (18), of a laser beam (14) of a laser beam device (22) having an optical arrangement (52), in particular for generating extreme ultraviolet radiation (EUV), comprising the following method steps: a) -determining (24) three beam diameters (26,32,36,40) of the laser beam (14) at three measuring planes (28,30,34,38) located along the laser beam propagation direction (16); b) -determining (42) the beam focus (12) of the laser beam (14) by calculating a beam propagation parameter of the laser beam (14) based on the three determined beam diameters (26,32,36,40) by analysis; c) -determining (46) a laser beam deviation by comparing the beam focus (12) of the laser beam (14) with a target beam focus (48); d) The laser beam device (22), in particular the optical device (52), is adjusted (50) as a function of the determined laser beam deviation.
  2. 2. The adjustment method (10) according to claim 1, wherein in step a) a far-field beam diameter (40) of the laser beam (14) is determined at a third measuring plane (38) located in the far field of the laser beam (14), wherein in step b) a divergence angle (44) of the laser beam (14) is determined from the far-field beam diameter (40).
  3. 3. The adjustment method (10) according to claim 2, wherein in step a) a first near field beam diameter (32) is determined at a first measurement plane (30) positioned in the near field of the laser beam (14) and a second near field beam diameter (36) is determined at a second measurement plane (34) positioned in the near field, wherein in step b) a focal position (18) is determined.
  4. 4. A method (10) of adjustment according to claim 3, wherein in step b) the beam waist diameter (20) is determined.
  5. 5. Adjustment method (10) according to claim 4, wherein in step b) the rayleigh length and/or the diffraction index is determined.
  6. 6. The adjustment method (10) according to any one of claims 3 to 5, wherein in step a) the second near field beam diameter (36) is determined spaced apart from the first near field beam diameter (32) by a near field measurement plane distance (56) between the first measurement plane (30) and the second measurement plane (34).
  7. 7. The adjustment method (10) according to any one of claims 3 to 6, wherein the first measurement plane (30) is positioned in front of the focal position (18) in the laser beam propagation direction (16).
  8. 8. The adjustment method (10) according to any one of claims 3 to 7, wherein the second measurement plane (34) is positioned behind the focal position (18) in the laser beam propagation direction (16).
  9. 9. The adjustment method (10) according to any one of the preceding claims, wherein at least one of the beam diameters (26,32,36,40), in particular all beam diameters, are determined by a graphical evaluation of a graphical picture (60) of a laser beam cross-section.
  10. 10. An adjustment system (58) for adjusting an optical device (52) of a laser beam apparatus (22) by determining a plurality of beam diameters (26,32,36,40) along a laser beam propagation direction (16) of a laser beam (14), the adjustment system being in particular configured for performing an adjustment method (10) according to any one of the preceding claims, the adjustment system having: -at least one image generating device (62, 64, 66), in particular a camera and/or a photodiode, for detecting the beam diameter (26,32,36,40) of the laser beam (14), wherein the image generating device (62, 64, 66) is configured to be positioned at least temporarily in a beam path of the laser beam (14); -a calculation unit (71) for determining a beam focus (12) from the detected beam diameter (26,32,36,40), and for determining a laser beam deviation by comparing the beam focus (12) with a target beam focus (48); -an output unit (72) for outputting the determined laser beam deviation.
  11. 11. The adjustment system (58) according to claim 10, having two image generating devices (62, 64, 66), in particular three image generating devices, wherein at least one, in particular all, of the image generating devices (62, 64, 66) is configured to be positionable in a fixed manner on the beam path of the laser beam (14).
  12. 12. A laser beam apparatus (22) having an optical device (52), in particular for generating EUV radiation, having an adjustment system (58) according to any of claims 10 or 11.

Description

Adjustment method, adjustment system, and laser beam apparatus Technical Field The invention relates to a method for adjusting the beam focus of a laser beam device having an optical arrangement. The invention also relates to an adjustment system. The invention also relates to a laser beam device. Background Laser beam devices are used in many different ways. A particular application of laser beam devices is the generation of extreme ultraviolet radiation (EUV radiation). In this process, a suitable material, in particular tin droplets, is exposed to the laser beam, so that the desired EUV radiation is produced. Laser beam devices for generating EUV radiation are used, for example, for the production of semiconductors. In the case of a laser beam device, in particular for EUV production, it must be ensured that the laser beam device and in particular the laser beam of the laser beam device meet a predetermined specification before its intended use. These specifications may include safety-related factors or factors that determine the quality and performance of the laser beam. To ensure this desired state of the laser beam device or laser beam, the beam focus of the laser beam is typically measured and evaluated. If the beam focus is not within the predetermined specifications, the optics on the laser system are typically adjusted or replaced. In this case, it is often necessary to measure the beam focus and correct the optics several times before the specification can be reached and the laser can be brought into operation as specified. Conventional methods explicitly point out detecting the laser beam by multiple cameras at multiple predetermined points along the beam axis. In this case, the camera is usually guided directly into the laser beam. In practice, the camera image is typically detected at least nine predetermined positions, typically up to fourteen predetermined positions. The beam focus is then determined from the camera image using statistical methods, in particular by means of a fitting function. The method known from the prior art has the disadvantage that a large number of measurements have to be made at different positions of the laser beam. This constitutes a considerable measurement effort. In addition, repeated measurements are often required to adjust the optics, which further increases the measurement effort. In addition, the measurement position of the laser beam is generally predetermined and cannot be changed without affecting the statistical evaluation. Thus, in particular in areas where the laser system is difficult to reach, the measurement can only be performed with the system partially disassembled and then reassembled. This further increases the measurement effort and thus the time and costs involved. Object of the Invention It is therefore an object of the present invention to provide a method and apparatus for reliably and quickly adjusting and using a laser beam apparatus. Disclosure of Invention According to the invention, this object is achieved by an adjustment method having the features of claim 1. This object is also achieved by an adjustment system having the features of claim 10. This object is also achieved by a laser beam device having the features of claim 12. The dependent claims describe preferred embodiments of the invention. According to the present invention, an adjustment method is provided. The adjustment method is configured for adjusting a beam focus of a laser beam of the laser beam apparatus. In particular, the laser beam device is configured and constructed for generating extreme ultraviolet radiation (EUV radiation) by irradiating suitable materials, such as tin droplets. Laser beam devices typically have optical means for generating a laser beam. Preferably, the adjustment method is configured for adjusting the optical device. This enables particularly effective adjustment of the laser beam device. The laser beam may be configured as a single beam or in the form of sub-beams. The beamlets may in particular be split by means of a beam splitter. Such a sub-beam can be used as a measuring beam for measuring and evaluating tasks, while another sub-beam is used as intended, in particular for generating extreme ultraviolet radiation. The adjustment method is particularly suitable for checking an already configured optical device. The configured optics are typically configured to form an approximate beam focus of the laser beam. In other words, the adjustment method is particularly suitable for fine adjustment of a laser beam apparatus. The adjusting method comprises the following method steps: In method step a) of the adjustment method, three beam diameters of the laser beam are determined at three measuring planes located in the direction of propagation of the laser beam. In other words, the radial extension of the laser beam with respect to the direction of propagation of the laser beam is detected at three different measurement positions. In particular,