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CN-116417885-B - Positioning adjustment method and device for laser light path

CN116417885BCN 116417885 BCN116417885 BCN 116417885BCN-116417885-B

Abstract

The invention relates to a positioning adjustment method and device for a laser light path, wherein the method comprises the steps of enabling calibration light with marks to be incident into an optical system of the laser along the light path of the laser, replacing a pre-selected optical lens in the optical system by a corresponding replacement lens, enabling the refractive index of the replacement lens relative to the calibration light to be the same as that of the corresponding optical lens in the optical system relative to laser of the laser, adjusting the position and angle of a mechanical structure where each replacement lens is located according to the light spot characteristics output by the calibration light from the optical system, and restoring the replacement lens into the corresponding optical lens to complete the positioning adjustment of the light path of the laser. The method of the invention introduces standard reticle light and replaces optical lenses, and does not need to change any design in the light path to adjust the position and angle of each optical lens in the optical system of the laser, so as to improve the output laser quality of the laser.

Inventors

  • ZHANG YANRU
  • KONG LINGHAO
  • WEI XIAOMA

Assignees

  • 北京科益虹源光电技术有限公司

Dates

Publication Date
20260512
Application Date
20211230

Claims (10)

  1. 1. A method for positioning and adjusting a laser light path, the method comprising: s1, using marked calibration light to enter an optical system of a laser along an optical path of the laser; S2, replacing the optical lens selected in advance in the optical system by a corresponding replacement lens, wherein the refractive index of the replacement lens relative to the calibration light is the same as that of the corresponding optical lens in the optical system relative to the laser of the laser; S3, adjusting the position and angle of the mechanical structure of each replaced lens according to the light spot characteristics of the light output by the calibration light from the optical system behind the replaced lens; s4, restoring the replacement lens into a corresponding optical lens to complete the optical path positioning adjustment of the laser.
  2. 2. The method of claim 1, wherein the optical system comprises, in order along the optical path, a first window, a second window, a mirror set, a first beam splitter, a first tunable mirror, a second tunable mirror, a third window, a fourth window, a refractive prism, and a second beam splitter.
  3. 3. The method of claim 2, wherein the seed light output by the first tunable mirror is reflected by the second tunable mirror and sequentially input to the third window and the fourth window for primary amplification, and then is incident to the refractive prism for refraction and then sequentially enters the fourth window and the third window for secondary amplification, and the secondarily amplified seed light is output after passing through the second beam splitter.
  4. 4. The method of claim 2, wherein the replacement lens comprises lenses for respectively replacing the first window, the second window, the mirror group, the first beam splitter, the third window, the fourth window, the refractive prism, and the second beam splitter.
  5. 5. The method of claim 1, wherein the collimated light is a reticle standard light, the collimated light having a predetermined divergence angle and spot size.
  6. 6. The method of claim 1, wherein the calibration light is visible light.
  7. 7. The method of claim 1, wherein the laser is a calcium fluoride excimer laser and the refractive index of the optical lens in the optical system relative to the laser light of the laser is 1.5.
  8. 8. The method of claim 7, wherein the calibration light has a wavelength of 532nm, the replacement lens is made of H-K1 glass, and the replacement lens has a refractive index of 1.5 with respect to the calibration light.
  9. 9. The method of claim 1, wherein the replacement lens is identical in structure to the corresponding optical lens.
  10. 10. A positioning adjustment device for a laser light path, the device comprising: A calibration light source for emitting a marked calibration light which is incident into an optical system of a laser to be adjusted along an optical path of the laser; A replacement lens for correspondingly replacing a preselected optical lens in the optical system, the refractive index of the replacement lens with respect to the calibration light being the same as the refractive index of the corresponding optical lens in the optical system with respect to the laser light of the laser; And the receiving device is used for receiving the light output by the calibration light from the optical system behind the replaced lens, analyzing the facula characteristics of the received light and determining the adjustment information of the position and the angle of the mechanical structure where the replaced lens is positioned.

Description

Positioning adjustment method and device for laser light path Technical Field The present invention relates to the field of laser technologies, and in particular, to a method and an apparatus for positioning and adjusting a laser optical path. Background Based on the characteristics of short wavelength and high power, excimer laser becomes a main light source for large-scale semiconductor integrated circuit lithography at present, and a photoetching machine is also the largest industrial application field of excimer lasers. As the lithography node is coming into the 32nm node, arF excimer lithography has become the dominant and is expected to be applied to the lower 22nm node and 16nm node. In this connection, research hotspots in the current excimer laser technology are mainly focused on excimer laser technology for lithography. With the decreasing lithography nodes, arF excimer lasers are required to have more stable narrow linewidths, greater output power, higher dose stability, and longer gas lifetimes. The prior method utilizes the annular cavity technology to input seed light into the gain amplifying cavity for multiple times, the residence time in the amplifying cavity is long, and the amplifying cavity works in a deep saturation state. The advantages of this approach over single pass amplification techniques are mainly higher efficiency, greater energy, more stable output, and wider output pulses. The exact control light path passes through the gain area of the gain amplifying cavity, and determines the success or failure of the annular cavity technology. The excimer laser is a gas laser, and has the general characteristics of larger volume, longer light path, high modularization degree and reduced coupling degree of each link, and the characteristics bring difficulty to the light path transmission design and adjustment. Meanwhile, whether the assembled optical-mechanical structure of the optical path can meet the design precision requirement or not has great difficulty in assembling and adjusting detection. Disclosure of Invention The invention provides a positioning and adjusting method and device for a laser light path, which are used for adjusting the position and angle of each optical lens in an optical system of a laser so as to improve the output laser quality of the laser. In one aspect of the present invention, a method for positioning and adjusting an optical path of a laser is provided, the method comprising: s1, using marked calibration light to enter an optical system of a laser along an optical path of the laser; S2, replacing the optical lens selected in advance in the optical system by a corresponding replacement lens, wherein the refractive index of the replacement lens relative to the calibration light is the same as that of the corresponding optical lens in the optical system relative to the laser of the laser; S3, adjusting the position and angle of the mechanical structure of each replaced lens according to the light spot characteristics of the light output by the calibration light from the optical system behind the replaced lens; s4, restoring the replacement lens into a corresponding optical lens to complete the optical path positioning adjustment of the laser. The optical system sequentially comprises a first window, a second window, a reflecting mirror group, a first beam splitter, a first tunable reflecting mirror, a second tunable reflecting mirror, a third window, a fourth window, a refractive prism and a second beam splitter along the light path. The seed light output by the first tuning reflector is reflected by the second tuning reflector and then sequentially input into the third window and the fourth window for primary amplification, then is incident into the refraction prism for refraction and then sequentially enters into the fourth window and the third window for secondary amplification, and the secondarily amplified seed light is output after passing through the second beam splitter. The replacement lens specifically comprises lenses which are respectively used for correspondingly replacing the first window, the second window, the reflecting mirror group, the first beam splitter, the third window, the fourth window, the refraction prism and the second beam splitter. The calibration light is cross standard light, and the calibration light has a preset divergence angle and a preset light spot size. Wherein the calibration light is visible light. The laser is a calcium fluoride excimer laser, and the refractive index of an optical lens in the optical system relative to the laser of the laser is 1.5. The wavelength of the calibration light is 532nm, the replacement lens is H-K1 glass, and the refractive index of the replacement lens relative to the calibration light is 1.5. Wherein the replacement lens has the same structure as the corresponding optical lens. In another aspect of the present invention, there is provided a positioning adjustment device for an optical