Fiber transmission laser direct writing lithography system based on dispersion compensation

Abstract

This application relates to a fiber-optic laser direct-write lithography system based on dispersion compensation. The system includes a laser, a dispersion compensation module, a beam splitting module, and a writing module arranged sequentially. The laser generates a femtosecond laser beam, which is sent to the dispersion compensation module. The femtosecond laser beam, after passing through the dispersion compensation module, emits a pulsed beam with negative dispersion. The pulsed beam with negative dispersion is polarized by the beam splitting module, and simultaneously, the negative dispersion cancels out the positive dispersion generated by the fiber array in the beam splitting module, outputting a multi-channel femtosecond pulse width writing beam. This multi-channel femtosecond pulse width writing beam is collimated and projected by the writing module, outputting a multi-channel diffraction-limited writing spot for parallel writing. This method can compensate for the nonlinear dispersion generated by a large-mode-field fiber array, achieving a femtosecond-level writing beam pulse width and improving writing efficiency.

Description

Technical Field

[0001] This application relates to the field of laser writing technology, and in particular to a fiber-optic transmission laser direct-write lithography system based on dispersion compensation. Background Technology

[0002] Two-photon laser direct writing technology, as a mature micro-nano fabrication technology, utilizes femtosecond laser pulses to induce a two-photon polymerization effect in photoresist, thereby achieving micro-nano structure fabrication that exceeds the diffraction limit.

[0003] Currently, femtosecond laser direct writing speed is relatively slow. Existing technologies improve writing speed by increasing the number of writing channels, often using spatial light modulators or diffractive optical elements to generate multiple parallel writing channels. Patent document CN113189846A discloses a dual-path parallel super-resolution laser printing device based on optical field modulation. The method includes: the laser emitted by the direct writing laser sequentially passes through the direct writing collimator, the direct writing anti-drift system, the direct writing energy control module, and the direct writing wavefront control module before entering the beam combining module; the laser emitted by the suppression laser sequentially passes through the suppression collimator, the suppression anti-drift system, the suppression energy control module, and the suppression wavefront control module before entering the beam combining module; the direct writing light is modulated in the direct writing wavefront control module, and the suppression light is modulated in the suppression wavefront control module. After the two beams are combined, two pairs of direct writing-suppression spot combinations are formed. However, although the device generates two writing beams with mutually perpendicular polarization directions using a polarization beam splitter and uses spatial light beam splitting and combining to improve the writing throughput, the optical path of the device is cumbersome and complex and the device is difficult to debug.

[0004] Furthermore, high-power femtosecond light propagating in optical fibers generates both linear and nonlinear dispersion. Second-order and third-order dispersion have the greatest impact on the pulse. Second-order dispersion, or group delay dispersion (GDD), is linear, while third-order dispersion (TOD) is nonlinear. Fiber dispersion significantly affects pulse width, widening the femtosecond pulse to the picosecond level and impacting the two-photon effect of the photoresist. Summary of the Invention

[0005] Therefore, it is necessary to address the aforementioned technical problems by providing a dispersion-compensated fiber-optic transmission laser direct-write lithography system that can reduce optical path complexity, facilitate multi-channel system expansion, and provide high writing throughput.

[0006] In a first aspect, this application provides a fiber-optic laser direct-write lithography system based on dispersion compensation. The system includes a laser, a dispersion compensation module, a beam splitting module, and a writing module arranged sequentially.

[0007] The laser generates a femtosecond laser beam, which is then fed to the dispersion compensation module. The femtosecond laser beam, after passing through the dispersion compensation module, emits a pulsed beam with negative dispersion. The pulsed beam with negative dispersion is then polarized by the beam splitting module. Simultaneously, the negative dispersion cancels out the positive dispersion generated by the fiber array in the beam splitting module, resulting in the output of a multi-channel femtosecond pulse width marking beam. This multi-channel femtosecond pulse width marking beam is then collimated and projected by the marking module, resulting in the output of a multi-channel diffraction-limited marking spot for parallel marking.

[0008] In one embodiment, the dispersion compensation module includes a grating pair and a roof prism. The femtosecond laser is emitted through the grating pair to the roof prism, refracted back into the grating pair by the roof prism, and emitted from the grating pair to the beam splitter.

[0009] In one embodiment, the prism pair is composed of a first prism, a second prism, and a second transmission grating. The first transmission grating and the second transmission grating are placed parallel to each other, and the first prism and the second prism are placed rotationally symmetrically between the first transmission grating and the second transmission grating.

[0010] In one embodiment, the beam splitting module includes a polarization-adjusting beam splitting module and a large-mode-field fiber module arranged sequentially in the direction of light propagation.

[0011] The pulsed beam with negative dispersion is polarized by the polarization adjustment beam splitter module to output the multi-channel pulsed beam, which contains linear negative dispersion and nonlinear negative dispersion. The multi-channel pulsed beam generates positive dispersion by the large mode field fiber module, which cancels out the linear and nonlinear negative dispersion in the multi-channel pulsed beam to generate the multi-channel femtosecond pulse width writing beam.

[0012] In one embodiment, the polarization adjustment beam splitter module includes a half-wave plate, a polarization beam splitter prism, and an optical fiber coupler.

[0013] The pulsed beam with negative dispersion is split into transmitted light and reflected light by passing through a combination of a half-wave plate and a polarizing beam splitter in sequence. The transmitted light and reflected light are then coupled to the large mode field fiber array module by the fiber coupler.

[0014] In one embodiment, the large mode field fiber module includes a large mode field fiber array, the output end of which is composed of closely packed bare fibers, and outputs the multi-channel femtosecond pulse width writing beam that maintains a single-mode light spot.

[0015] In one embodiment, the writing module includes a collimating lens, a 4F imaging system, and a microscope objective arranged sequentially in the optical path direction. Each circular solid direct writing beam in the multi-channel femtosecond pulse width writing optical path is collimated into parallel light by the collimating lens, and then focused by the 4F imaging system and the microscope objective to output the multi-channel diffraction-limited writing spot for parallel writing.

[0016] In one embodiment, the 4F imaging system includes a scanning lens and a field lens arranged in sequence. The spot of the parallel light is conjugated by the scanning lens to the back focal plane of the field lens and focused and output by the microscope objective.

[0017] In one embodiment, the system further includes a first reflection module, which includes a first reflector and a second reflector, through which the femtosecond laser passes sequentially to the dispersion compensation module.

[0018] In one embodiment, the system further includes a second reflection module, which includes a third and a fourth reflector, through which the pulsed beam with negative dispersion passes sequentially to the beam splitter.

[0019] The aforementioned fiber-optic laser direct-write lithography system based on dispersion compensation comprises a laser, a dispersion compensation module, a beam splitting module, and a writing module arranged sequentially. The laser generates a femtosecond laser beam, which is then fed to the dispersion compensation module. The femtosecond laser beam, after passing through the dispersion compensation module, emits a pulsed beam with negative dispersion. This pulsed beam with negative dispersion is then polarized by the beam splitting module, and the negative dispersion cancels out the positive dispersion generated by the fiber array in the beam splitting module, outputting a multi-channel femtosecond pulse width writing beam. This multi-channel femtosecond pulse width writing beam is collimated and projected by the writing module, outputting a multi-channel diffraction-limited writing spot for parallel writing. This system compensates for the nonlinear dispersion generated by the large-mode-field fiber array, outputs a writing beam pulse width on the order of femtoseconds, and improves writing efficiency. Attached Figure Description

[0020] Figure 1 This is a structural block diagram of a fiber-optic transmission laser direct-write lithography system based on dispersion compensation in one embodiment;

[0021] Figure 2 This is a schematic diagram of a fiber-optic transmission laser direct-write lithography system based on dispersion compensation in one embodiment. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0023] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0024] In one embodiment, such as Figure 1 As shown, a fiber-optic laser direct-write lithography system based on dispersion compensation is provided. The system includes a laser 101, a dispersion compensation module 102, a beam splitting module 103, and a writing module 104 arranged sequentially. The laser 101 generates a femtosecond laser beam, which is transmitted to the dispersion compensation module 102. The femtosecond laser beam, after passing through the dispersion compensation module 102, emits a pulsed beam with negative dispersion. The pulsed beam with negative dispersion is polarized by the beam splitting module 103, and the negative dispersion cancels out the positive dispersion generated by the large-mode-field fiber in the beam splitting module, outputting a multi-channel femtosecond pulse width writing beam. The multi-channel femtosecond pulse width writing beam is collimated and projected by the writing module 104, outputting a multi-channel diffraction-limited writing spot for parallel writing.

[0025] In the aforementioned fiber-optic transmission laser direct-write lithography system based on dispersion compensation, the complexity of the writing optical path is greatly reduced by using laser 101, dispersion compensation module 102, beam splitting module 103, and writing module 104. The nonlinear dispersion generated in the fiber array is compensated, and multi-channel femtosecond-level writing beam pulse width is achieved, thereby improving writing efficiency.

[0026] In one embodiment, such as Figure 2 As shown, the dispersion compensation module 102 includes a grating pair 21 and a roof prism 22. The femtosecond laser is emitted through the grating pair 21 to the roof prism 22, and refracted back into the grating pair 21 through the roof prism 22. The pulsed beam with negative dispersion is emitted from the grating pair 21 to the beam splitter 103.

[0027] Specifically, such as Figure 2 As shown, the prism pair 21 is composed of a first transmission grating 211, a first prism 212, a second prism 213, and a second transmission grating 214. The first transmission grating 211 and the second transmission grating 214 are placed in parallel, and the first prism 212 and the second prism 213 are placed rotationally symmetrically between the first transmission grating 211 and the second transmission grating 214.

[0028] For example, after passing through the first transmission grating 211, the first prism 212, the second prism 213, and the second transmission grating 214, the femtosecond laser reaches the first reflecting surface of the roof prism 22. After passing through the second reflecting surface of the roof prism 22, it re-enters the grating pair 21 and passes through the second transmission grating 214, the second prism 213, the first prism 212, and the first transmission grating 211 in sequence. By optimizing the grating pair parameters, a pulsed beam with negative second-order dispersion and negative third-order dispersion is output to the beam splitter 103.

[0029] In this embodiment, linear negative dispersion and nonlinear negative dispersion are generated by prism pairs and roof prisms to cancel out the linear positive dispersion and nonlinear positive dispersion generated by the femtosecond pulse beam passing through the optical fiber, thereby achieving dispersion compensation in the writing device and avoiding pulse width broadening of the writing beam caused by nonlinear dispersion.

[0030] In one embodiment, such as Figure 2 As shown, the beam splitting module 103 includes a polarization adjustment beam splitting module 31 and a large mode field fiber module 32 arranged sequentially in the direction of light propagation.

[0031] The pulsed beam with negative dispersion is polarized by the polarization adjustment beam splitter 31 to output the multi-channel pulsed beam, which contains linear negative dispersion and nonlinear negative dispersion. The multi-channel pulsed beam generates positive dispersion by the large mode field fiber module 32, which cancels out the linear and nonlinear negative dispersion in the multi-channel pulsed beam to generate the multi-channel femtosecond pulse width writing beam.

[0032] Specifically, the polarization adjustment beam splitting module 31 includes a half-wave plate 311, a polarization beam splitting prism 312, and an optical fiber coupler 313. The pulsed beam with negative dispersion is split into transmitted light and reflected light by each combination of the half-wave plate 311 and the polarization beam splitting prism 312. The optical fiber coupler 313 then couples the transmitted and reflected light beams to the large-mode-field fiber array module 32.

[0033] Specifically, the large mode field fiber module 32 includes a large mode field fiber array 321, the output end of which is composed of closely arranged bare fibers, and outputs the multi-channel femtosecond pulse width writing beam that maintains a single-mode light spot.

[0034] Compared to ordinary single-mode fiber, large-mode-field fiber arrays have a larger mode field diameter. According to the fiber nonlinear dispersion formula, assuming that the MFD of ordinary single-mode fiber is 3 micrometers and the MFD of large-mode-field fiber is 9 micrometers, the nonlinear dispersion length of large-mode-field fiber is 9 times that of ordinary single-mode fiber. Large-mode-field fiber can effectively reduce fiber nonlinear dispersion, and the 517nm wavelength can maintain a single-mode spot after passing through large-mode-field fiber.

[0035] For example, a pulsed beam with negative dispersion passes sequentially through a combination of a half-wave plate 311 and a polarizing beam splitter 312. The polarization direction of the beam is adjusted by the half-wave plate 311. The pulsed beam with negative dispersion is divided into transmitted P-beam and reflected S-beam. The transmitted P-beam and reflected S-beam beams are coupled into the input end of the large mode field fiber array 321 by the fiber coupler 313.

[0036] In this embodiment, by simultaneously increasing the number of half-wave plates, polarizing beam splitters, and fiber couplers in the polarization adjustment module, the number of the final output writing beams is adjusted, thereby achieving parallel writing with any number of channels.

[0037] In one embodiment, such as Figure 2As shown, the writing module 104 includes a collimating lens 41, a 4F imaging system 42, and a microscope objective 43 arranged sequentially in the direction of light propagation. Each circular solid direct writing beam in the multi-channel femtosecond pulse width writing optical path is collimated into parallel light by the collimating lens 41, and then focused by the 4F imaging system 42 and the microscope objective 43 to output the multi-channel diffraction-limited writing spot for parallel writing.

[0038] Specifically, such as Figure 2 As shown, the 4F imaging system 42 includes a scanning lens 421 and a field lens 422 arranged in sequence. The spot of the parallel light is conjugated to the back focal plane of the field lens 422 by the scanning lens 421 and then focused and output by the microscope objective 43.

[0039] For example, each circular solid direct writing beam in the multi-channel writing optical path output by the large mode field fiber array 321 is collimated into parallel light by the collimating lens 41. The parallel light is then conjugated to the back focal plane of the field lens 422 by the scanning lens 421, and finally focused by the microscope objective 43 to output a multi-channel diffraction-limited writing spot.

[0040] In this embodiment, by setting a collimating lens 41, a scanning lens 421, a field lens 422, and a microscope objective 43, the multi-channel writing optical path output by the large mode field fiber array 321 is focused into a multi-channel diffraction-limited writing spot, thereby realizing multi-channel parallel writing and improving writing efficiency.

[0041] In one embodiment, such as Figure 2 As shown, the fiber-optic laser direct-write lithography system based on dispersion compensation also includes a first reflection module 105, which includes a first reflector 61 and a second reflector 62. The femtosecond laser passes sequentially through the first reflector 61 and the second reflector 62 to the dispersion compensation module 21.

[0042] Specifically, the femtosecond laser generated by the laser 101 enters the dispersion compensation module 21 after passing through the first reflector 61 and the second reflector 62.

[0043] In one embodiment, such as Figure 2 As shown, the fiber-optic transmission laser direct-write lithography system based on dispersion compensation also includes a second reflection module 106, which includes a third reflector 63 and a fourth reflector 64. The pulsed beam with negative dispersion passes sequentially through the third reflector 63 and the fourth reflector 64 to the beam splitting module 31.

[0044] Specifically, the pulsed beam with negative dispersion emitted from the dispersion compensation module 102 passes through the third reflector 63 and the fourth reflector 64 and then enters the beam splitting module 103.

[0045] In one example embodiment, a fiber-optic laser direct-write lithography system based on dispersion compensation is provided, comprising a laser 101 for generating a 517nm femtosecond laser, a first reflection module 105, a dispersion compensation module 102, a second reflection module 106, a beam splitting module 103, and a writing module 104 arranged sequentially. The dispersion compensation module 102 includes a grating pair 21 composed of a first transmission grating 211, a first prism 212, a second prism 213, and a second transmission grating 214, and a roof prism 22. The first reflection module 105 includes a first reflector 61 and a second reflector 62. The second reflection module 106 includes a third reflector 63 and a fourth reflector 64. The beam splitting module 103 includes a six-channel polarization-adjustable beam splitting module 31 composed of a half-wave plate 311, a polarization beam splitting prism 312, and a fiber coupler 313, and a large-mode-field fiber array 321. The writing module 104 includes a collimating lens 41, a scanning lens 421, a field lens 422, and a microscope objective lens 43 arranged sequentially in the direction of light propagation.

[0046] The femtosecond laser generated by laser 101 passes sequentially through the first reflecting mirror 61 and the second reflecting mirror 62 of the first reflecting module 105, and then enters the prism pair 21 of the dispersion compensation module 102. The femtosecond laser then passes sequentially through the first transmission grating 211, the first prism 212, the second prism 213, and the second transmission grating 214 of the prism pair 21, reaching the roof prism 22 of the dispersion compensation module 102. After reflection by the roof prism 22, it re-enters the prism pair 21, and then sequentially passes through the second transmission grating of the prism pair 21. The first prism 212 and the first transmission grating 211 emit a pulsed beam with negative dispersion to the polarization adjustment beam splitter 31 of the beam splitter 103. Each time the pulsed beam with negative dispersion passes through a combination of a half-wave plate 311 and a polarization beam splitter 312, the pulsed beam with negative dispersion is split into a transmitted P-beam and a reflected S-beam. The transmitted P-beam and the reflected S-beam are coupled and output by the fiber coupler 313 to obtain a multi-channel pulsed beam to the large mode field fiber array 321. When the multi-channel pulsed beam passes through the large-mode-field fiber array 321, it generates positive second-order and positive third-order dispersion, which cancels out the negative second-order and negative third-order dispersion generated after passing through the dispersion compensation module 102. The multi-channel femtosecond pulse width writing beam is output to the collimating lens 41 of the writing module 104. The collimating lens 41 collimates each circular solid straight writing beam in the multi-channel writing optical path into parallel light, which is then emitted onto the scanning lens 421 of the writing module 104. The parallel light is conjugated to the back focal plane of the field lens 422 by the scanning lens 421, and finally focused by the microscope objective 43 to output a multi-channel diffraction-limited writing spot for parallel writing of the sample.

[0047] In this example implementation, a combination of prism pairs and a large-mode-field fiber array is used. The prism pairs provide negative second-order and negative third-order dispersion to compensate for the positive second-order and positive third-order dispersion generated by the incident femtosecond laser in the large-mode-field fiber array, so that the output light of the fiber array maintains a femtosecond pulse width. At the same time, half-wave plates, polarizing beam splitters and fiber couplers are used to increase the writing channels and improve the writing efficiency.

[0048] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0049] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. The embodiments described above merely illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A dispersion-compensated optical-fiber transmission laser direct writing lithography system, characterized by, The system includes a laser, a dispersion compensation module, a beam splitting module, and a writing module arranged sequentially. The laser generates a femtosecond laser beam, which is then fed to the dispersion compensation module. The femtosecond laser beam passes through the dispersion compensation module and emits a pulsed beam with negative dispersion. The pulsed beam with negative dispersion is polarized and adjusted by the beam splitting module. Simultaneously, the negative dispersion cancels out the positive dispersion generated by the fiber array in the beam splitting module, resulting in the output of a multi-channel femtosecond pulse width marking beam. The multi-channel femtosecond pulse width marking beam is collimated and projected by the marking module, resulting in the output of a multi-channel diffraction-limited marking spot for parallel marking. The beam splitting module includes a polarization-adjusting beam splitting module and a large-mode-field fiber module arranged sequentially in the direction of light propagation. The pulsed beam with negative dispersion is polarized by the polarization adjustment beam splitter module to output a multi-channel pulsed beam containing linear and nonlinear negative dispersion. The multi-channel pulsed beam generates positive dispersion by the large mode field fiber module, which cancels out the linear and nonlinear negative dispersion in the multi-channel pulsed beam, generating the multi-channel femtosecond pulse width writing beam.

2. The fiber-optic laser direct-write lithography system based on dispersion compensation according to claim 1, characterized in that, The dispersion compensation module includes a grating pair and a roof prism. The femtosecond laser is emitted through the grating pair to the roof prism, refracted back into the grating pair by the roof prism, and then emitted from the grating pair to the beam splitter.

3. The fiber-optic laser direct-write lithography system based on dispersion compensation according to claim 2, characterized in that, The grating pair is composed of a first transmission grating, a first prism, a second prism, and a second transmission grating. The first transmission grating and the second transmission grating are placed parallel to each other, and the first prism and the second prism are placed rotationally symmetrically between the first transmission grating and the second transmission grating.

4. The fiber-optic laser direct-write lithography system based on dispersion compensation according to claim 1, characterized in that, The polarization-adjusting beam splitter module includes a half-wave plate, a polarization beam splitter prism, and an optical fiber coupler. The pulsed beam with negative dispersion is split into transmitted light and reflected light by passing through a combination of a half-wave plate and a polarizing beam splitter in sequence. The transmitted light and reflected light are then coupled to the large mode field fiber module by the fiber coupler.

5. The fiber-optic laser direct-write lithography system based on dispersion compensation according to claim 4, characterized in that, The large mode field fiber module includes a large mode field fiber array, the output end of which is composed of closely packed bare fibers, and outputs the multi-channel femtosecond pulse width writing beam that maintains a single-mode light spot.

6. The fiber-optic laser direct-write lithography system based on dispersion compensation according to claim 1, characterized in that, The writing module includes a collimating lens, a 4F imaging system, and a microscope objective arranged sequentially in the optical path direction. Each circular solid direct writing beam in the multi-channel femtosecond pulse width writing optical path is collimated into parallel light by the collimating lens, and then focused by the 4F imaging system and the microscope objective to output the multi-channel diffraction-limited writing spot for parallel writing.

7. The dispersion-compensated optical-fiber delivery laser direct-write lithography system of claim 6, wherein, The 4F imaging system includes a scanning lens and a field lens arranged in sequence. The spot of parallel light is conjugated by the scanning lens to the back focal plane of the field lens and focused and output by the microscope objective.

8. The fiber-optic laser direct-write lithography system based on dispersion compensation according to claim 1, characterized in that, The system also includes a first reflection module, which includes a first reflector and a second reflector. The femtosecond laser passes sequentially through the first reflector and the second reflector to the dispersion compensation module.

9. The fiber-optic laser direct-write lithography system based on dispersion compensation according to claim 1, characterized in that, The system also includes a second reflection module, which includes a third and a fourth reflector. The pulsed beam with negative dispersion passes sequentially through the third and fourth reflectors to the beam splitter.

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