Light path adjusting system for holographic exposure light path

Abstract

The utility model provides a light path adjusting system for a holographic exposure light path, which comprises a beam expanding and collimating assembly and a light path adjusting assembly, the light path adjusting assembly comprises a light spot analysis device, and the light spot analysis device is placed at one end of the beam expanding and collimating assembly for receiving an incident light beam. According to the light path adjusting system provided by the utility model, when the holographic exposure light path repeatedly adopts the selected beam expanding and collimating assembly, the holographic exposure light path can be rapidly reproduced based on the correspondingly recorded light spot diameter and morphology parameters of the incident light beam, or when the parameters of part of components in the beam expanding and collimating assembly in the holographic exposure light path are replaced, the holographic exposure light path can be rapidly reproduced based on the light spot diameter and morphology parameters of the incident light beam. Under the condition that the light intensity uniformity of the parallel light beams emitted by the incident light beam through the beam expanding and collimating assembly meets the light path requirement, the light spot diameter and morphology parameters of the required incident light beam are quickly locked.

Description

Technical Field

[0001] The utility model belongs to the technical field of grating exposure, and in particular relates to an optical path adjustment system for a holographic exposure optical path. Background Art

[0002] Diffraction gratings are optical components with periodic microstructures or refractive index modulation. They perform functions such as beam splitting, dispersion, phase matching, and polarization state modulation, playing an important role in interferometry, spectroscopy, and laser pulse compression. The period of a diffraction grating typically ranges from a few hundred nanometers to tens of microns.

[0003] The main methods for fabricating diffraction gratings include mechanical ruling, electron beam direct writing, X-ray lithography, and holographic ion beam etching. Holographic ion beam etching utilizes a holographic exposure system to expose a substrate coated with photoresist. After development, a photoresist grating mask is applied to the substrate. An ion beam etcher is then used to etch the substrate with the photoresist grating mask, completing the diffraction grating fabrication. Holographic ion beam etching offers advantages such as low cost, controllable groove shape, and the absence of ghost lines, and has been widely used in the fabrication of diffraction gratings.

[0004] The holographic exposure system includes a beam expansion and collimation component, which in turn includes a microscope, a pinhole filter, and a collimating lens. The pinhole filter is positioned at the focal point of the microscope's focal plane. After being focused by the microscope, the laser's emitted light beam forms a main spot centered on the focal plane. Since the laser's emitted light beam contains high-frequency noise, there is stray light around the main spot. Therefore, a pinhole filter is currently positioned at the focal point of the microscope's focal plane. The pinhole size of the pinhole filter matches the size of the main spot, thereby filtering out the stray light around the main spot. The component beams of the main spot are then expanded and enter the collimating lens as expanded beams for collimation.

[0005] However, in an actual holographic exposure system, many factors affect the filtering effect of stray light around the main light spot, resulting in poor light intensity uniformity of the parallel light beams obtained by expanding the component light beams of the main light spot and then entering the collimating lens for collimation. Therefore, it is also necessary to adjust the optical path of the holographic exposure system until the light intensity uniformity of the parallel light beams obtained by expanding the component light beams of the main light spot and then entering the collimating lens for collimation meets the requirements. Utility Model Content

[0006] In order to overcome the defects of the prior art, the utility model provides a light path adjustment system for a holographic exposure light path.

[0007] The utility model adopts the following technical solutions:

[0008] The utility model provides an optical path adjustment system for a holographic exposure optical path, comprising a beam expansion and collimation component and an optical path adjustment component;

[0009] The optical path adjustment component includes a light spot analysis device, and the light spot analysis device is placed at the end of the beam expansion and collimation component that receives the incident light beam.

[0010] Furthermore, the beam expansion and collimation assembly includes a microscope objective lens, a pinhole filter and a collimating lens in sequence;

[0011] The pinhole filter is arranged at the focus of the focal plane of the microscope objective.

[0012] Furthermore, the light spot analysis device is placed at the end of the microscope objective lens that receives the incident light beam.

[0013] Furthermore, the optical path adjustment component also includes a focusing device;

[0014] The focusing device is placed at one end of the beam expansion and collimation assembly that receives the incident light beam.

[0015] Furthermore, the optical path adjustment component further includes a receiving board and an optical power measuring device;

[0016] The receiving plate is arranged at one end of the outgoing light beam of the beam expansion and collimation assembly;

[0017] The optical power measuring device measures the intensity of the incident light beam on the receiving plate.

[0018] Furthermore, a plurality of measuring points are provided on the receiving plate;

[0019] The optical power measuring device measures the intensity of the incident light beam on the receiving plate at a measuring point.

[0020] Furthermore, the focusing device adopts a focusing lens.

[0021] Furthermore, the receiving plate is a fluorescent plate, and the optical power measuring device is an optical power meter.

[0022] Compared with the prior art, the technical solution of the utility model has the following beneficial effects:

[0023] The utility model provides an optical path adjustment system for a holographic exposure optical path, comprising a beam expansion and collimation component and an optical path adjustment component, wherein the optical path adjustment component comprises a light spot analysis device, the light spot analysis device being placed at one end of the beam expansion and collimation component for receiving an incident light beam, and when the beam expansion and collimation component is selected, the light spot diameter and shape of the incident light beam can be changed according to the light intensity uniformity distribution of a parallel light beam emitted by the beam expansion and collimation component, the light spot analysis device measures the light spot diameter and shape of the incident light beam of the beam expansion and collimation component, and records the light spot diameter and shape parameters of the incident light beam displayed by the light spot analysis device at this time when the light intensity uniformity of the parallel light beam emitted by the beam expansion and collimation component meets the optical path requirements. The optical path adjustment system provided by the present invention can quickly reproduce the holographic exposure optical path based on the corresponding recorded spot diameter and morphology parameters of the incident light beam when the selected beam expansion and collimation component is repeatedly used in the holographic exposure optical path, or can quickly lock the required spot diameter and morphology parameters of the incident light beam when the component parameters of some components in the beam expansion and collimation component in the holographic exposure optical path are replaced, while ensuring that the light intensity uniformity of the parallel light beam emitted by the beam expansion and collimation component meets the optical path requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1 Schematic diagram of the structure of an existing dual-beam exposure system as an example;

[0026] Figure 2 A schematic structural diagram of an existing Laue mirror exposure system is shown as an example;

[0027] Figure 3 Schematic diagram of the structure of an existing beam expansion and collimation assembly as an example;

[0028] Figure 4 This is a schematic diagram showing how the spot diameter of the laser beam after it is focused by the microscope objective lens changes with the transmission distance;

[0029] Figure 5 The structure diagram of the optical path adjustment system for holographic exposure optical path of the utility model is shown as an example;

[0030] Figure 6 Schematic diagram of the distribution of measurement points in an exemplary receiving plate.

[0031] Among them, 1-laser, 2-first wave plate, 3-beam splitting prism, 4-second wave plate, 5-reflecting mirror, 5-1-first reflecting mirror, 5-2-second reflecting mirror, 5-3-third reflecting mirror, 6-microscope objective lens, 6-1-first microscope objective lens, 6-2-second microscope objective lens, 7-pinhole filter, 7-1-first pinhole filter, 7-2-second pinhole filter, 8-collimating lens, 8-1-first collimating lens, 8-2-second collimating lens, 9-light shielding plate, 10-Laue mirror, 11-sample holder, 12-spot analysis device, 13-focusing device, 14-receiving plate, 15-measuring point. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] In this document, the terms "first", "second" and other similar words are not intended to imply any order, quantity and importance, but are merely used to distinguish different elements. In this document, the terms "one", "an" and other similar words are not intended to indicate that there is only one of the things described, but rather that the relevant description is only for one of the things described, and the things described may have one or more. In this document, the terms "comprise", "include" and other similar words are intended to indicate logical relationships, and cannot be regarded as indicating relationships in spatial structure. For example, "A includes B" is intended to indicate that B logically belongs to A, and does not mean that B is spatially located inside A. In addition, the meanings of the terms "comprise", "include" and other similar words should be regarded as open, not closed. For example, "A includes B" is intended to indicate that B belongs to A, but B does not necessarily constitute the whole of A, and A may also include other elements such as C, D, and E.

[0034] In this document, the terms "embodiment," "present embodiment," "preferred embodiment," and "one embodiment" do not imply that the description applies only to a specific embodiment, but rather that the description may also apply to one or more other embodiments. Those skilled in the art should understand that any description of a particular embodiment herein may be substituted, combined, or otherwise combined with the description of one or more other embodiments. New embodiments resulting from such substitution, combination, or other combination are readily conceivable by those skilled in the art and fall within the scope of protection of this utility model.

[0035] In the description herein, “a plurality of” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0036] There are two existing holographic exposure systems used to prepare diffraction gratings using holographic ion beam etching, including a dual-beam exposure system and a Laue mirror exposure system.

[0037] like Figure 1 The figure shows a schematic diagram of the structure of an existing double-beam exposure system, which includes a laser 1, a first wave plate 2, a beam splitting prism 3, a second wave plate 4, a first reflector 5-1, a second reflector 5-2, a third reflector 5-3, a first microscope objective 6-1, a second microscope objective 6-2, a first pinhole filter 7-1, a second pinhole filter 7-2, a first collimating lens 8-1, and a second collimating lens 8-2. The emission beam of the laser 1 is incident on the first wave plate 2, and the polarization state is adjusted by the first wave plate 2 before the beam is incident on the beam splitting prism 3. The beam splitting prism 3 splits the beam into two beams. The first beam is reflected by the third reflector 5-3 and enters the first microscope objective 6-1. After being focused by the first microscope objective 6-1, it enters the first pinhole filter 7-1 (located at the focus of the first microscope objective 6-1). After being filtered by the first pinhole filter 7-1, it enters the first collimating lens 8-1. After being collimated by the first collimating lens 8-1, it becomes a first parallel beam. After the polarization state of the two beams is adjusted by the second wave plate 4, they are reflected by the first reflector 5-1 and the second reflector 5-2 in sequence before entering the second microscope objective 6-2. After being focused by the second microscope objective 6-2, they enter the second pinhole filter 7-2 (located at the focal point of the second microscope objective 6-2). After being filtered by the second pinhole filter 7-2, they enter the second collimating lens 8-2. After being collimated by the second collimating lens 8-2, they become a second parallel beam. The first parallel beam and the second parallel beam form an interference field on the surface of the sample to be exposed. In the dual-beam exposure system, the direction along the grating vector is regarded as the x-direction, the direction along the grating lines is regarded as the y-direction, and the direction along the normal of the sample to be exposed is regarded as the z-direction.

[0038] like Figure 2As shown in FIG, it is a schematic structural diagram of an existing Laue mirror exposure system, which includes a laser 1, a reflector 5, a first wave plate 2, a beam splitter prism 3, a second wave plate 4, a microscope objective 6, a pinhole filter 7, a collimating lens 8, a light shielding plate 9 and a Laue mirror 10. The emitted light beam from laser 1 is reflected by reflector 5 and incident on first wave plate 2. Its polarization state is adjusted by first wave plate 2 and then incident on beam splitter 3, which splits the light beam into two beams. The transmitted light beam is polarized by second wave plate 4 and then enters microscope objective 6. Focused by microscope objective 6, it enters pinhole filter 7. After filtering by pinhole filter 7, it enters collimating lens 8. Collimated by collimating lens 8, it becomes a parallel beam and is directed toward baffle 9. After the beam area is adjusted by baffle 9, a portion of the parallel beam enters Laue mirror 10. Another portion of the parallel beam, after the beam area is adjusted by baffle 9, enters the sample to be exposed in sample holder 11. The parallel beam entering Laue mirror 10 is reflected and incident on the sample to be exposed in sample holder 11. The two parallel beams form an interference field on the surface of the sample to be exposed. In the Laue mirror exposure system, the direction of the grating vector is the x-direction, the direction along the grating lines is the y-direction, and the direction along the normal of the sample to be exposed is the z-direction.

[0039] Combine Figure 1 as well as Figure 2 It can be seen that the existing holographic exposure system includes a beam expansion and collimation component composed of a microscope objective lens 6, a pinhole filter 7 and a collimating lens 8 (such as Figure 3 (As shown). After the laser beam is focused by the microscope objective lens, it forms a main spot centered on the focal point, with stray light around the main spot. The pinhole filter is used to filter out the stray light around the main spot.

[0040] However, in an actual holographic exposure system, many factors affect the filtering effect of stray light around the main light spot, resulting in poor light intensity uniformity of the parallel light beams obtained by expanding the component light beams of the main light spot and then entering the collimating lens for collimation. Therefore, it is actually necessary to adjust the optical path of the holographic exposure system until the light intensity uniformity of the parallel light beams obtained by expanding the component light beams of the main light spot and then entering the collimating lens for collimation meets the requirements, and the optical path adjustment is relatively cumbersome.

[0041] In order to solve this problem, the utility model provides an optical path adjustment system for a holographic exposure optical path. The optical path adjustment system includes a beam expansion and collimation component and an optical path adjustment component.

[0042] For example, the beam expansion and collimation component is the beam expansion and collimation component in the existing holographic exposure system, such as Figure 5As shown, the beam expansion and collimation assembly includes a microscope objective lens 6, a pinhole filter 7 and a collimating lens 8 in sequence. The pinhole filter 7 is arranged at the focus of the focal plane of the microscope objective lens 6. The pinhole size of the pinhole filter matches the spot size of the main light spot formed at the focus of the focal plane after the laser's emission light beam is focused by the microscope objective lens.

[0043] The magnification of the microscope objective lens can be selected based on the spot diameter of the incident light beam of the microscope objective lens.

[0044] Since the laser's emission beam is a typical Gaussian beam, the spot radius of the laser's emission beam after being converged by the microscope objective lens changes with the transmission distance in a hyperbolic manner (e.g. Figure 4 As shown in Figure 2), and the beam cross-section intensity presents a Gaussian distribution, the diameter of the pinhole filter can be selected by the following formula:

[0045]

[0046] Where D is the diameter of the pinhole filter, λ is the wavelength of the incident light, F is the focal length of the microscope lens, and d is the laser beam attenuated to e at the focal position through the microscope lens. -2 The beam waist diameter d can be obtained by calculation.

[0047] The optical path adjustment component includes a light spot analysis device, which is placed at one end of the beam expansion and collimation component that receives the incident light beam.

[0048] For example, the beam expansion and collimation assembly includes a microscope objective lens, a pinhole filter and a collimating lens in sequence, and the spot analysis device 12 is placed at the end of the microscope objective lens 6 receiving the incident light beam (such as Figure 5 shown).

[0049] Exemplarily, the light spot analysis device may adopt an existing light spot analyzer.

[0050] When a beam expansion and collimation component is selected (for example, when the microscope objective magnification and the pinhole filter diameter are selected), the spot diameter and morphology of the incident light beam can be changed according to the intensity uniformity distribution of the parallel light beam emitted by the beam expansion and collimation component. The spot analysis device measures the spot diameter and morphology of the incident light beam of the beam expansion and collimation component until the intensity uniformity of the parallel light beam emitted by the beam expansion and collimation component meets the optical path requirements, and the spot diameter and morphology parameters of the incident light beam displayed by the spot analysis device at this time are recorded.

[0051] The optical path adjustment system provided by the present invention can quickly reproduce the holographic exposure optical path based on the corresponding recorded spot diameter and morphology parameters of the incident light beam when the selected beam expansion and collimation component is repeatedly used in the holographic exposure optical path, or when the component parameters of some components in the beam expansion and collimation component in the holographic exposure optical path are replaced (for example, the microscope objective lens magnification and / or the pinhole filter diameter are changed), while ensuring that the light intensity uniformity of the parallel light beam emitted by the incident light beam through the beam expansion and collimation component meets the optical path requirements, the optical path adjustment system can quickly lock the required spot diameter and morphology parameters of the incident light beam.

[0052] As a preferred embodiment, the optical path adjustment assembly may further include a focusing device, which is placed at the end of the beam expansion and collimation assembly that receives the incident light beam.

[0053] The focusing device is placed at the end of the beam expander and collimator assembly that receives the incident light beam. By adjusting the relative distance between the focusing device and the beam expander and collimator assembly, the spot diameter and morphology of the incident light beam of the beam expander and collimator assembly can be changed. Taking the beam expander and collimator assembly as an example, which includes a microscope objective lens, a pinhole filter and a collimator lens in sequence, the focusing device 13 is placed at the end of the microscope objective lens 6 that receives the incident light beam (such as Figure 5 (As shown in the figure), the spot diameter and shape of the incident beam of the beam expander and collimator are changed by adjusting the relative distance between the focusing device and the microscope objective lens. Using the focusing device to change the spot diameter and shape of the incident beam of the beam expander and collimator can significantly reduce operating costs compared to changing the spot diameter and shape of the incident beam of the beam expander and collimator by changing the laser.

[0054] Exemplarily, the focusing device may use an existing focusing lens, such as a lens of smaller size.

[0055] As a preferred embodiment, the optical path adjustment component may further include a receiving board and an optical power measuring device.

[0056] The receiving plate is arranged at one end of the outgoing beam of the beam expanding and collimating assembly, and the receiving plate receives the outgoing beam of the beam expanding and collimating assembly. Taking the beam expanding and collimating assembly including the microscope objective lens, the pinhole filter and the collimating lens in sequence as an example, the receiving plate 14 is arranged at one end of the outgoing beam of the collimating lens 6, and the receiving plate 14 receives the outgoing beam of the collimating lens 6 (such as Figure 5 shown).

[0057] The optical power measuring device measures the intensity of the incident light beam of the receiving plate, thereby obtaining the intensity distribution of the output light beam of the collimating lens. Based on the intensity distribution of the output light beam of the collimating lens, the uniformity of the intensity distribution of the output light beam of the collimating lens can be judged.

[0058] Preferably, a plurality of measuring points may be provided on the receiving board, and the optical power measuring device measures the intensity of the incident light beam on the receiving board at the measuring points.

[0059] For example, Figure 6 As shown, five measuring points 15 are set on the receiving plate 14, one of which is located at the center of the receiving plate and receives the light beam at the center of the light beam emitted by the collimating lens. The remaining four measuring points are respectively arranged on the periphery of the measuring point at the center and are at the same distance from the measuring point at the center. The remaining four measuring points receive the light beam at the edge of the light beam emitted by the collimating lens.

[0060] For example, the receiving plate may be a fluorescent plate, and the optical power measuring device may be an existing optical power meter.

[0061] The following example illustrates a method for using the optical path adjustment system of the present invention to assist in optical path adjustment:

[0062] 1. Select the required microscope objective lens, pinhole filter, and collimating lens to build the beam expansion and collimation assembly:

[0063] A microscope objective with the required magnification is selected based on the spot diameter of the incident light beam.

[0064] Based on the selected microscope objective, a pinhole filter with the desired pinhole diameter is selected using the following formula:

[0065]

[0066] Where D is the diameter of the pinhole filter, λ is the wavelength of the incident light, F is the focal length of the microscope lens, and d is the laser beam attenuated to e at the focal position through the microscope lens. -2 The beam waist diameter d can be obtained by calculation.

[0067] There are no special requirements for the selection of collimating lenses.

[0068] A microscope objective lens, a pinhole filter, and a collimating lens are arranged in sequence from left to right, and the pinhole filter is located at a focal position of the focal plane of the microscope objective lens.

[0069] 2. Initially place the focusing device at the incident beam end of the microscope objective lens and the receiving plate at the outgoing beam end of the collimating lens.

[0070] 3. Place a spot analysis device between the focusing device and the microscope objective lens, start the laser, and the laser's emission beam enters the spot analysis device after passing through the focusing device. Record the spot diameter and morphology parameters of the incident microscope objective lens displayed by the spot analysis device. Move the spot analysis device away. The laser's emission beam passes through the microscope objective lens, pinhole filter, and collimating lens in sequence after passing through the focusing device. After exiting through the collimating lens, it is received by the receiving board. The optical power measuring device measures the light intensity distribution of the received beam on the receiving board.

[0071] 4. If the intensity distribution uniformity of the received light beam on the receiving plate does not meet the requirements, adjust the distance between the focusing device and the microscope objective lens and continue the operation of step 3 above. By continuously adjusting the distance between the focusing device and the microscope objective lens and repeating the operation of step 3 above, the intensity distribution uniformity of the received light beam on the receiving plate meets the requirements.

[0072] 5. When the holographic exposure optical path repeatedly uses the above-selected microscope objective lens, pinhole filter and collimating lens as the beam expansion and collimation component, the holographic exposure optical path is quickly reproduced based on the corresponding recorded spot diameter and morphology parameters of the incident microscope objective lens, or when the component parameters of some components in the beam expansion and collimation component in the holographic exposure optical path are replaced (for example, the microscope objective lens magnification and / or the pinhole filter diameter are changed), the spot diameter and morphology parameters of the required incident light beam are quickly locked while ensuring that the light intensity uniformity of the parallel light beam emitted by the beam expansion and collimation component meets the optical path requirements.

[0073] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the same. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field can still modify or replace the specific implementation methods of the present invention. Any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention to be approved.

Claims

1. An optical path adjustment system for a holographic exposure optical path, characterized in that: Including beam expansion and collimation components and optical path adjustment components; The optical path adjustment component includes a light spot analysis device, and the light spot analysis device is placed at the end of the beam expansion and collimation component that receives the incident light beam.

2. The optical path adjustment system for holographic exposure optical path according to claim 1, characterized in that: The beam expansion and collimation assembly includes a microscope objective lens, a pinhole filter and a collimating lens in sequence; The pinhole filter is arranged at the focus of the focal plane of the microscope objective.

3. The optical path adjustment system for holographic exposure optical path according to claim 2, characterized in that: The light spot analysis device is placed at the end of the microscope objective lens that receives the incident light beam.

4. The optical path adjustment system for holographic exposure optical path according to claim 1, characterized in that: The optical path adjustment component also includes a focusing device; The focusing device is placed at one end of the beam expansion and collimation assembly that receives the incident light beam.

5. The optical path adjustment system for holographic exposure optical path according to claim 1, characterized in that: The optical path adjustment component also includes a receiving board and an optical power measuring device; The receiving plate is arranged at one end of the outgoing light beam of the beam expansion and collimation assembly; The optical power measuring device measures the intensity of the incident light beam on the receiving plate.

6. The optical path adjustment system for holographic exposure optical path according to claim 5, characterized in that: A plurality of measuring points are arranged on the receiving plate; The optical power measuring device measures the intensity of the incident light beam on the receiving plate at a measuring point.

7. The optical path adjustment system for holographic exposure optical path according to claim 4, characterized in that: The focusing device adopts a focusing lens.

8. The optical path adjustment system for holographic exposure optical path according to claim 5, characterized in that: The receiving plate is a fluorescent plate, and the optical power measuring device is an optical power meter.

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