A wavefront lithography method and system

Abstract

The present invention discloses a wavefront lithography method and system, comprising the following steps: S1, decomposing wavefront information into a plurality of sub-wavefront information; S2, using macro-pixels to decompose, encode and lithographically output sub-wavefront information with speckle dissipation and Gaussian distribution removal one by one, and the macro-pixel unit contains the amplitude and phase information of the sub-wavefront information; it can realize real-time modulation of arbitrary interference angles of reference light and object light in a 4π solid angle space, can efficiently prepare complex micro-nano structures with high uniformity and speckle dissipation noise; can improve the signal-to-noise ratio of wavefront information, reduce the influence of the Gaussian distribution of light intensity by the laser, and obtain high-quality wavefront information.

Description

Technical Field

[0001] The present invention relates to the field of lithography manufacturing, and particularly to a wavefront lithography method and system. Background Art

[0002] Lithography technology is the core technology for fabricating micro-nano structure devices. Current lithography technologies include focused energy beam lithography technology, interference lithography technology, holographic lithography technology, etc. Among them, focused energy beam lithography technology includes focused ion beam direct writing systems represented by Zeiss Auriga and FEI NOVA 600; focused electron beam lithography systems represented by Joel JBX9300 and Leica VB6; laser lithography systems represented by Micronic Sigma and AppliedMaterial ALTA, etc. The processing area and processing efficiency of such technical equipment are limited, the use cost is high, and they are monopolized by foreign brands. Introducing such equipment usually requires tens of millions of dollars. Interference lithography technology can efficiently fabricate large-area micro-nano structures. However, the structures that can be processed are single and cannot meet the requirements for manufacturing complex structures. Holographic lithography technology, such as the technology disclosed in Chinese Patent Application No. 202111480688.4, combines holographic technology and interference lithography technology to achieve the fabrication of relatively complex micro-nano structures. However, the currently disclosed holographic lithography technology is still difficult to achieve real-time modulation of the interference angle, and there are problems such as serious speckle noise, the light intensity being affected by the Gaussian distribution of the laser, and low structural uniformity. Summary of the Invention

[0003] In order to solve the problems in the prior art that the interference angle is difficult to be modulated in real time, the speckle noise is serious, the light intensity is affected by the Gaussian distribution of the laser, and the structural uniformity is low, the present invention provides a wavefront lithography method and system, which can achieve real-time modulation of any interference angle in the 4π solid angle space and efficiently fabricate complex micro-nano structures with high uniformity and reduced speckle noise.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A wavefront lithography method includes the following steps:

[0006] S1. Decompose the wavefront information into several sub-wavefront information;

[0007] S2. Use macro-pixels to individually decompose, encode and lithographically output sub-wavefront information with reduced speckle and Gaussian distribution removed. The macro-pixel unit contains the amplitude and phase information of the sub-wavefront information. It can achieve micro-nano structures with high uniformity and reduced speckle noise.

[0008] Preferably, S2 includes:

[0009] S21. Record macro-pixels one by one on the photosensitive material through the interference of the object light and the reference light of the wavefront lithography system;

[0010] S22. Modulate the wavefront information by refreshing the object light and transforming the reference light;

[0011] S23. Use diffraction inversion calculation to encode the amplitude and phase information into the corresponding amplitude or phase transmittance distribution map;

[0012] S24. Input the amplitude or phase transmittance distribution map into the spatial light modulator in the object light wavefront subsystem of the wavefront lithography system. Under the illumination of the object light beam, the distribution map reproduces its encoded sub-wavefront information through diffraction;

[0013] S25. The reproduced sub-wavefront information interferes with the reference light in the reference light wavefront subsystem of the wavefront lithography system to form macro-pixels. It can achieve real-time modulation of arbitrary interference angles with high uniformity and dissipate speckle noise.

[0014] Preferably, the diffraction inversion calculation method includes holographic calculation, iteration, simulated annealing or genetic algorithm optimization algorithms under band-limited speckle dissipation and de-Gaussian illumination light field. It can achieve high-precision optimization calculation.

[0015] A wavefront lithography system includes an illumination subsystem. Behind the illumination subsystem, there is an object light wavefront subsystem, and behind the illumination subsystem, there is a reference light wavefront subsystem. There are a motion subsystem and a control subsystem connected to the object light wavefront subsystem and the reference light wavefront subsystem. The illumination subsystem includes a steerable beam splitter device; the object light wavefront subsystem includes a diffraction device. The diffraction device is connected to a beam combining prism, the beam combining prism is connected to a spatial light modulator, the spatial light modulator is connected to a Fourier transform lens, and the spatial light modulator is located on the input surface of the Fourier transform lens. The diffraction device forms a speckle-dissipating and de-Gaussian light field distribution on the plane where the spatial light modulator is located and on the output surface of the Fourier transform lens. The illumination subsystem includes a laser light source, and the laser light source is connected to an expanding and collimating device, and the expanding and collimating device is connected to the steerable beam splitter device. It can achieve simultaneous de-Gaussian speckle dissipation in the near field and the far field. The reference light wavefront subsystem includes a first reference light optical path for corresponding to the first 2π solid angle space; a second reference light optical path for corresponding to the second 2π solid angle space; both the first reference light optical path and the second reference light optical path are provided with scanning galvanometers, and the scanning galvanometers are connected to scanning lenses; in the first reference light optical path, the scanning lens is connected to a Fourier transform lens, and in the second reference light optical path, the scanning lens is connected to a converging lens. The object light wavefront subsystem forms a coaxial optical path with the first reference optical path and the second reference optical path through the beam combining prism, and the light fields output by the object light wavefront subsystem and the reference light wavefront subsystem coincide on the output surface of the Fourier transform lens or on the image surface of the output surface. It can achieve variable parameter object angles in the 4π solid space.

[0016] Preferably, the object light wavefront subsystem further includes a field stop for restricting the output surface of the Fourier transform lens and a micro-imaging optical path for microscopically imaging the light field on the output surface of the Fourier transform lens. It can perform microscopic imaging on the output surface of the Fourier transform lens, thereby performing lithography of micro-nano structures.

[0017] Preferably, the object light wavefront subsystem further includes an autofocus optical path and a real-time monitoring optical path. It can ensure clear imaging and real-time monitoring of the imaging results, facilitating timely modulation.

[0018] Preferably, the motion subsystem includes: a two-dimensional translation stage located behind the output surface of the Fourier transform lens; a scanning galvanometer driver connected to the scanning galvanometer, and a steering motor connected to the steerable beam splitter device; the control subsystem is respectively connected to the illumination subsystem, the object light wavefront subsystem, the reference light wavefront subsystem, and the motion subsystem, and is used to coordinately control the switching of the continuous laser and the start-stop motion of the motion subsystem. It can perform real-time modulation of the interference angle and multi-parameter tuning.

[0019] The present invention has the following advantages:

[0020] It can realize real-time modulation of arbitrary interference angles in the 4π solid angle space, can efficiently fabricate complex micro-nano structures with high uniformity and speckle noise dissipation, can fabricate large-area micro-nano structures with high efficiency, can realize the fabrication of relatively complex micro-nano structures, can perform real-time modulation of the interference angle, can reduce the speckle noise in the wavefront information, reduce the influence of the Gaussian distribution of the light intensity on the laser, and has good structural uniformity. Brief Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings described below are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0022] Figure 1 is a schematic structural diagram of the present invention.

[0023] Figure 2 is a schematic diagram of the second embodiment of the present invention.

[0024] In the figure:

[0025] 1 - Continuous laser; 2 - Beam expander; 3 - Collimator; 4 - Steerable beam splitter; 5 - Mirror; 6 - Aperture stop; 7 - Scanning galvanometer; 8 - Scanning lens; 9 - Beam combining prism; 10 - Spatial light modulator; 11 - Fourier transform lens; 12 - Two-dimensional translation stage; 13 - Control subsystem; 14 - Scanning galvanometer driver; 15 - Photosensitive material; 16 - Light field; 17 - First output light field; 19 - Converging lens; 20 - Diffraction device; 21 - Second output light field; 22 - Steering motor; 23 - Auto-focusing system; 24 - Auto-focusing motor; 25 - Real-time monitoring system; 26 - Pulse laser; 27 - Transmissive spatial light modulator; 28 - Field stop; 29 - Dichroic mirror; 30 - Miniature interference spot; 39 - Miniature lens group. Detailed implementation mode

[0026] The following specific embodiments illustrate the implementation modes of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0027] As Figure 1 shown, in the first embodiment, the present invention discloses a wavefront lithography system, including: an illumination subsystem, an object wavefront subsystem is provided behind the illumination subsystem, a reference wavefront subsystem is provided behind the illumination subsystem, a motion subsystem and a control subsystem 13 connected to the object wavefront subsystem and the reference wavefront subsystem. The illumination subsystem includes a continuous laser 1, the continuous laser 1 is connected with a beam expander 2, the beam expander 2 is connected with a collimator 3, the collimator and the continuous laser are respectively located on both sides of the beam expander, the collimator 3 is connected with a steerable beam splitter 4, and the steerable beam splitter and the beam expander are respectively located on both sides of the collimator; the object wavefront subsystem includes a diffraction device 20, the diffraction device and the collimator are respectively located on both sides of the steerable beam splitter, the diffraction device 20 is connected with a beam combining prism 9, the beam combining prism and the steerable beam splitter are respectively located on both sides of the diffraction device, the beam combining prism is connected with a spatial light modulator 10, the spatial light modulator and the diffraction device are respectively located on both sides of the beam combining prism, and the beam combining prism is connected with a Fourier transform lens 11; the spatial light modulator 10 is located on the input surface of the Fourier transform lens 11, and light forms a speckle-free and Gaussian-removed light field 16 on the plane where the spatial light modulator 10 is located and on the output surface of the Fourier transform lens 11 through the diffraction device 20. A photosensitive material 15 is provided on the output surface after the Fourier transform lens.

[0028] The reference optical wavefront subsystem includes a first reference optical path corresponding to a first 2π solid angle space and a second reference optical path corresponding to a second 2π solid angle space. The first and second reference optical paths are switched by a steerable beam splitter 4. The first reference optical path includes a mirror 5, which is connected to an aperture stop 6. Behind the aperture stop, there is a scanning galvanometer 7. The scanning galvanometer is connected to a scanning lens 8, and behind the scanning lens is connected to a beam combining prism. The scanning lens and the Fourier transform lens 11 are located on both sides of the beam combining prism respectively. The scanning lens 8 and the Fourier transform lens 11 form a 4f system. The first reference optical path forms a first output optical field 17 on the output surface of the Fourier transform lens. The second reference optical path includes a mirror 5, an aperture stop 6, a scanning galvanometer 7, and a scanning lens 8 corresponding to the first reference optical path on both sides of the Fourier transform lens. Behind the scanning lens of the second reference optical path, there is a converging lens 19. The second reference optical path forms a second output optical field 21 on the output surface of the converging lens 19. The object optical wavefront subsystem forms a coaxial optical path with the first reference optical path and the second reference optical path through the beam combining prism. The first output optical field 17 formed by the first reference optical path, the second output optical field 21 formed by the second reference optical path, and the optical field 16 formed by the object optical wavefront subsystem on the output surface of the Fourier transform lens coincide.

[0029] The motion subsystem at least includes a two-dimensional translation stage 12, which is connected to a photosensitive material, a scanning galvanometer driver 14 connected to the scanning galvanometer, and a steering motor 22 connected to the steerable beam splitter.

[0030] The control subsystem is connected to the illumination subsystem, the object optical wavefront subsystem, the reference optical wave subsystem, and the motion subsystem, and coordinately controls the switching of the continuous laser, the steering of the steering motor, the image output of the spatial light modulator, and the motion of the motion subsystems such as the scanning galvanometer driver and the two-dimensional translation stage.

[0031] The continuous laser 1 emits light, which forms a wide parallel beam after beam expansion and collimation. The wide parallel beam is split into a transmitted part and a reflected part by the steerable beam splitter 4. The transmitted light enters the object optical wavefront subsystem, and the reflected light enters the reference optical wavefront subsystem. The transmitted light illuminates the diffraction device 20 and forms a band-limited, Gaussian-removed, speckle-reduced illumination optical field on the plane where the reflective phase-type spatial light modulator 10 is located through the beam combining prism. The illumination optical field is modulated by the spatial light modulator and then reflected and enters the Fourier transform lens 11 through the beam combining prism. A Gaussian-removed, speckle-reduced optical field 16 is formed on the output surface of the Fourier transform lens. The optical field 16 is modulated by refreshing the spatial light modulator.

[0032] The direction of the reflected light of the steerable beam splitter 4 can be modulated by the steering motor 22. When the steerable beam splitter 4 is in the orientation corresponding to the first reference light optical path, the first reference light optical path forms the first output light field 17 through the mirror 5, the aperture stop 6, the scanning galvanometer 7, the scanning lens 8, and the Fourier transform lens 11. The direction of the first output light field 17 is modulated within the first 2π solid angle space by the two-dimensional scanning of the scanning galvanometer 7. The first output light field 17 coincides with the light field 16 on the surface of the photosensitive material 15 and forms a macro-pixel through interference.

[0033] When the steerable beam splitter 4 is in the orientation corresponding to the second reference light optical path, the second reference light optical path forms the second output light field 21 through the mirror 5 corresponding to the second reference optical path, the aperture stop 6, the scanning galvanometer 7, the scanning lens 8, and the converging lens 19. The direction of the second output light field 21 is modulated within the second 2π solid angle space by the two-dimensional scanning of the scanning galvanometer 7. The second output light field 21 coincides with the light field 16 on the surface of the photosensitive material 15 and forms a macro-pixel through interference.

[0034] The control subsystem outputs macro-pixels one by one according to the timing sequence, thereby realizing wavefront lithography.

[0035] The method of the present invention is as follows: decompose the wavefront information into several sub-wavefront information, and use macro-pixels to decompose, encode, and lithographically output the sub-wavefront information one by one. The sub-wavefront information encoded by the macro-pixels has the characteristics of simultaneously dissipating speckles and removing Gaussian distribution in the near field and the far field. The macro-pixels are recorded on the photosensitive material one by one through the interference of the object light and the reference light of the wavefront lithography system. The wavefront information of the macro-pixels is modulated by refreshing the object light and / or transforming the reference light. Each macro-pixel unit contains the amplitude and phase information of the sub-wavefront information. The decomposition and encoding method of the macro-pixels encodes the amplitude and phase information into the amplitude or phase transmittance distribution map corresponding to the macro-pixels by using diffraction inversion calculation. Input the amplitude or phase transmittance distribution map into the spatial light modulator in the object light wavefront subsystem of the wavefront lithography system. Under the illumination of the object light beam, the distribution map reproduces its encoded sub-wavefront information through diffraction. The reproduced sub-wavefront information interferes with the reference light in the reference light wavefront subsystem of the wavefront lithography system to form a macro-pixel. The information modulation of the macro-pixels is realized by combining one or several of the following methods: refreshing the spatial light modulator, rotating the beam splitter, and rotating the scanning galvanometer. The diffraction inversion calculation method includes but is not limited to optimization algorithms such as holographic calculation, iteration, simulated annealing, and genetic algorithm under a limited-band speckle-removing and Gaussian-removing illumination light field.

[0036] As Figure 2As shown, in the second embodiment, the illumination subsystem includes a pulsed laser 26, the object wavefront subsystem includes a transmissive spatial light modulator 27, a field stop 28 is provided behind the Fourier transform lens, a dichroic mirror 29 is provided behind the field stop, the dichroic mirror is connected to a microlens group 39, a dichroic mirror 22 is provided in the microlens group, an autofocus system 23 is provided on one side of the microlens group adjacent to the dichroic mirror, and the autofocus system is provided with an autofocus motor 24; the microlens group 39 is connected to the photosensitive material 15 behind.

[0037] The pulsed laser 26 outputs laser light, which forms a wide parallel light beam after beam expansion and collimation. The wide parallel light beam is divided into a transmitted part and a reflected part by the steerable beam splitter 4. Among them, the transmitted light enters the object wavefront subsystem, and the reflected light enters the reference wavefront subsystem. The transmitted light passes through the diffraction device 20 to illuminate the spatial light modulator 27, and a speckle-free and Gaussian-removed light field 16 is formed on the plane where the transmissive spatial light modulator 27 is located. The transmissive spatial light modulator 27 is located on the input surface of the Fourier transform lens 11, and the light field after modulation by the transmissive spatial light modulator forms a speckle-free and Gaussian-removed light field 16 on the output surface of the Fourier transform lens 11. The light field 16 is modulated by refreshing the spatial light modulator. The light field 16 passes through the field stop 28 and is then microscopically imaged on the surface of the photosensitive material 15 through the microlens group 39. The autofocus system 23 ensures that the microlens group 39 can accurately image on the surface of the photosensitive material. The real-time monitoring system 25 monitors the surface of the photosensitive material 15 in real time.

[0038] The direction of the reflected light of the steerable beam splitter 4 can be modulated by the steering motor 22. When the steerable beam splitter 4 is in the orientation corresponding to the first reference light optical path, the first reference light optical path forms a first output light field 17 through the mirror 5, the aperture stop 6, the scanning galvanometer 7, the scanning lens 8, and the Fourier transform lens 11. The direction of the first output light field 17 is modulated within the first 2π solid angle space by the two-dimensional scanning of the scanning galvanometer 7. The first light field 17 and the light field 16 overlap and interfere on the plane where the field stop 28 is located. After the overlapping area of the light field 16 and the first light field 17 passes through the field stop 28, a micro interference spot 30 is formed on the surface of the photosensitive material 15 through the microlens group 39. The micro interference spot 30 forms a macro pixel on the surface of the photosensitive material.

[0039] When the steerable beam splitter 4 is in the orientation corresponding to the optical path of the second reference light, the optical path of the second reference light forms the second output light field 21 through the mirror 5, the aperture stop 6, the scanning galvanometer 7, the scanning lens 8, and the focusing lens 19. The direction of the second output light field 21 is modulated within the second 2π solid angle space through the two-dimensional scanning of the scanning galvanometer 7. The reduced image formed by the reduced lens group 39 on the surface of the photosensitive material 15 of the light field 16 interferes with the second output light field 21 to form a reduced interference spot 30. The reduced interference spot 30 forms a macro-pixel on the surface of the photosensitive material.

[0040] The control subsystem outputs macro-pixels one by one according to the timing sequence, thereby realizing wavefront lithography.

[0041] Although the present invention has been described in detail with general descriptions and specific embodiments above, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A wavefront lithography method, characterized in that, It includes the following steps: S1. Decompose the wavefront information into several sub-wavefront information; S2. Use macro-pixels to decompose, encode and lithographically output the sub-wavefront information with speckle suppression and de-Gaussian distribution one by one. Use diffraction inversion calculation to encode the amplitude and phase information of the sub-wavefront into the corresponding amplitude or phase transmittance distribution map. Input the amplitude or phase transmittance distribution map into a spatial light modulator. Under the illumination of the object beam, the distribution map reproduces its encoded sub-wavefront information through diffraction. The reproduced sub-wavefront information interferes with the reference light in the reference light wavefront subsystem of the wavefront lithography system to form a macro-pixel. A macro-pixel is an interference image unit formed by the interference of the object light and the reference light. The macro-pixel unit contains the amplitude and phase information of the sub-wavefront information.

2. The method of wavefront lithography according to claim 1, wherein S2 It includes: S21. Record one by one on the photosensitive material through the interference of the object light and the reference light of the wavefront lithography system; S22. Realize the modulation of the wavefront information through the refresh of the object light and the transformation of the reference light; S23. Use diffraction inversion calculation to encode the amplitude and phase information of the sub-wavefront into the corresponding amplitude or phase transmittance distribution map under the limited-band speckle-suppressed and de-Gaussian illumination light field; S24. Input the amplitude or phase transmittance distribution map into the spatial light modulator in the object light wavefront subsystem of the wavefront lithography system. Under the illumination of the object beam, the distribution map reproduces its encoded sub-wavefront information through diffraction; S25. The reproduced sub-wavefront information interferes with the reference light in the reference light wavefront subsystem of the wavefront lithography system to form a macro-pixel.

3. The method of wavefront lithography according to claim 2, wherein, The diffraction inversion calculation method includes optimization algorithms such as holographic calculation, iteration, simulated annealing or genetic algorithm.

4. A wavefront lithography system, applicable to a wavefront lithography method as described in any one of claims 1 to 3, characterized in that, It includes an illumination subsystem, an object light wavefront subsystem, a reference light wavefront subsystem, a motion subsystem and a control subsystem. The illumination subsystem includes a steerable beam splitter device; the object light wavefront subsystem includes a diffraction device. The diffraction device is connected with a beam combining prism. The beam combining prism is connected with a spatial light modulator. The spatial light modulator is connected with a Fourier transform lens. The spatial light modulator is located on the input surface of the Fourier transform lens. The diffraction device forms a speckle-suppressed and de-Gaussian light field distribution on the plane where the spatial light modulator is located and on the output surface of the Fourier transform lens; the reference light wavefront subsystem includes a first reference light optical path for corresponding to the first 2π solid angle space; A second reference light optical path for corresponding to the second 2π solid angle space; Scanning galvanometers are provided on both the first reference light optical path and the second reference light optical path. The scanning galvanometers are connected with scanning lenses; The scanning lens in the first reference light optical path is connected with a Fourier transform lens, and the scanning lens in the second reference light optical path is connected with a converging lens.

5. A wavefront lithography system according to claim 4, wherein The object light wavefront subsystem further includes a field stop for restricting the output surface of the Fourier transform lens and a micro-imaging optical path for microscopically imaging the light field on the output surface of the Fourier transform lens.

6. A wavefront lithography system according to claim 4 or 5, characterized in that The object light wavefront subsystem further includes an autofocus optical path and a real-time monitoring optical path.

7. The wavefront lithography system according to claim 6, wherein The motion subsystem includes: a two-dimensional translation stage, which is located behind the output surface of the Fourier transform lens; a scanning galvanometer driver connected to the scanning galvanometer, and a steering motor connected to the steerable beam splitter device; the control subsystem is respectively connected to the illumination subsystem, the object optical wavefront subsystem, the reference optical wavefront subsystem and the motion subsystem, and is used to coordinately control the switching of the continuous laser and the start-stop motion of the motion subsystem.

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