Processing device of field emission cathode and field emission cathode

Abstract

The utility model provides a processing device of a field emission cathode and the field emission cathode, and belongs to the technical field of laser processing, and the processing device of the field emission cathode comprises a laser used for emitting laser; the beam expander is arranged at the output end of the laser and used for converting the laser into beam-expanded laser; the spatial light modulator is arranged at the output end of the beam expander and used for converting the beam-expanded laser into modulated laser according to a preset pattern; the optical scaling system is arranged at the output end of the spatial light modulator and used for converting the modulated laser into scaled laser; and the focusing objective lens is arranged at the output end of the optical zooming system and is used for converting the zoomed laser into focused laser. According to the field emission cathode processing device provided by the embodiment of the invention, the field emission cathode can be processed through laser etching, the field emission cathode with good morphology consistency and excellent uniformity can be formed, and the field emission cathode processing device is suitable for large-scale production and processing of the field emission cathode.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser processing, in particular to a processing device of a field emission cathode and the field emission cathode. BACKGROUND

[0002] The field emission cathode is a key component of vacuum microelectronics, and its performance directly affects the overall performance of the device. The field emission vacuum electron device manufactured based on the field emission cathode has the characteristics of radiation resistance, static resistance and temperature characteristics. Among them, lanthanum hexaboride (LaB6) has the advantages of low escape power, high melting point, low evaporation rate, stable chemical properties, strong ion bombardment resistance and good heat conduction performance, and is an ideal material for manufacturing field emission cathodes. However, due to the stable physical and chemical properties of lanthanum hexaboride, it is difficult to process this material using conventional methods such as particle beam etching, electron beam exposure and chemical etching, and the hard and brittle characteristics of the material also lead to brittle fracture during mechanical micro-processing.

[0003] In related technologies, lanthanum hexaboride field emission cathodes are usually processed using wet etching and electrochemical etching methods. However, the surface morphology, height and bottom flatness of the lanthanum hexaboride field emission cathodes obtained by these processing methods are not ideal, and the process cycle is relatively long. CONTENT OF THE INVENTION

[0004] Embodiments of the present application provide a processing device of a field emission cathode and a field emission cathode, which can obtain a field emission cathode with good morphology consistency and excellent uniformity.

[0005] In a first aspect, embodiments of the present application provide a processing device of a field emission cathode, comprising:

[0006] A laser for emitting laser light;

[0007] A beam expander arranged at the output end of the laser for converting the laser light into expanded laser light;

[0008] A spatial light modulator arranged at the output end of the beam expander for converting the expanded laser light into modulated laser light according to a predetermined pattern;

[0009] An optical zoom system arranged at the output end of the spatial light modulator for converting the modulated laser light into zoomed laser light;

[0010] A focusing objective lens arranged at the output end of the optical zoom system for converting the zoomed laser light into focused laser light.

[0011] In some embodiments, the processing device of the field emission cathode further comprises a 1 / 2 glass and a 1 / 4 glass;

[0012] The 1 / 2 glass is arranged between the output end of the beam expander and the receiving end of the spatial light modulator.

[0013] A 1 / 4 glass is arranged between the output end of the spatial light modulator and the receiving end of the optical zoom system.

[0014] In some embodiments, further comprising a light splitting prism and a power receiving feedback device;

[0015] The light splitting prism is arranged between the 1 / 2 glass and the receiving end of the spatial light modulator.

[0016] The first light beam output by the light splitting prism enters the spatial light modulator, and the second light beam output by the light splitting prism enters the power receiving feedback device.

[0017] In some embodiments, the processing device of the field emission cathode further comprises a moving platform;

[0018] The moving platform is arranged at the output end of the focusing objective lens, and is used to carry the workpiece to be processed and adjust the relative position between the workpiece to be processed and the focusing objective lens.

[0019] In some embodiments, the processing device of the field emission cathode further comprises a first reflector and a second reflector;

[0020] The first reflector is arranged between the output end of the beam expander and the receiving end of the light splitting prism.

[0021] The second reflector is arranged between the output end of the spatial light modulator and the receiving end of the optical zoom system.

[0022] In some embodiments, the laser comprises a green femtosecond laser; the repetition frequency of the laser is ≤1MHz, the pulse width is <250fs, and the average power is ≤20W.

[0023] In some embodiments, the optical zoom system comprises a first lens and a second lens; the first lens is arranged between the output end of the spatial light modulator and the receiving end of the focusing objective lens; the second lens is arranged between the first lens and the receiving end of the focusing objective lens; wherein the focal length of the first lens is smaller than the focal length of the second lens.

[0024] In some embodiments, the wavelength range of the spatial light modulator is 532nm±50nm, and the pixel size is 7.8μm.

[0025] And / or, the numerical aperture of the focusing objective lens is 2, the focal length is 2mm, and the resolution is 0.24μm.

[0026] In a second aspect, the embodiments of the present application further provide a processing method of a field emission cathode, based on the processing device of the field emission cathode as described above, comprising:

[0027] Placing the workpiece to be processed at the output end of the focusing objective lens.

[0028] The laser emits laser light, and the beam expander expands the laser light to form expanded laser light;

[0029] The spatial light modulator converts the expanded laser light into modulated laser light according to a preset pattern;

[0030] The optical zoom system adjusts the pixel size of the modulated laser light to form zoomed laser light;

[0031] The focusing objective lens converts the zoomed laser light into focused laser light and etches the surface of the workpiece to be processed by the focused laser light to obtain the field emission cathode.

[0032] In some embodiments, after etching the surface of the workpiece to be processed by the focused laser light, the method further comprises:

[0033] Adjusting the relative position of the workpiece to be processed and the focusing objective lens to etch again.

[0034] In a third aspect, the embodiments of the present application also provide a field emission cathode, which is obtained by the processing device or the processing method of the field emission cathode as described above.

[0035] In some embodiments, the material of the field emission cathode is lanthanum hexaboride.

[0036] The embodiments of the present application have the following beneficial effects:

[0037] The processing device of the field emission cathode provided by the embodiments of the present application comprises a laser, a beam expander, a spatial light modulator, an optical zoom system, and a focusing objective lens. The laser can emit laser light, the beam expander is arranged at the output end of the laser, the spatial light modulator is arranged at the output end of the beam expander, the optical zoom system is arranged at the output end of the spatial light modulator, and the focusing objective lens is arranged at the output end of the optical zoom system. The laser light emitted by the laser forms expanded laser light after passing through the beam expander, and the expanded laser light can form modulated laser light according to a preset pattern after passing through the spatial light modulator. The modulated laser light is zoomed by the optical zoom system to obtain zoomed laser light with a suitable pixel size, and then the zoomed laser light passes through the focusing objective lens to make the focused laser light act on the workpiece to be processed, thereby completing the laser etching of the workpiece to be processed. The etching precision of the laser etching is high, the stability is good, the process is simple, and the field emission cathode with good topographic consistency and excellent uniformity can be formed, which is suitable for large-scale production and processing of the field emission cathode. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0039] Figure 1 This is a schematic diagram of the structure of the field emission cathode processing apparatus provided in the embodiments of this application;

[0040] Figure 2 This is a schematic diagram of the structure of the field emission cathode provided in the embodiments of this application.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Laser; 2. Beam expander; 3. Spatial light modulator; 4. Optical scaling system; 41. First lens; 42. Second lens; 5. Focusing objective; 6. Moving platform; 7. Half-glass slide; 8. Quarter-glass slide; 9. Beam splitter prism; 10. Power receiver feedback unit; 11. First mirror; 12. Second mirror; 20. Field emission cathode; 21. Conical structure. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0044] Firstly, such as Figure 1 As shown in the embodiment of this application, the processing apparatus for a field emission cathode includes a laser 1, a beam expander, a spatial light modulator 3, an optical scaling system 4, and a focusing lens 5. The laser 1 emits laser light. The beam expander is located at the output end of the laser 1, the spatial light modulator 3 is located at the output end of the beam expander, the optical scaling system 4 is located at the output end of the spatial light modulator 3, and the focusing lens 5 is located at the output end of the optical scaling system 4. The laser emitted by the laser 1 is expanded by the beam expander. After passing through the spatial light modulator 3, the expanded laser is modulated according to a preset pattern. The modulated laser is scaled by the optical scaling system 4 to obtain a scaled laser of appropriate pixel size. Then, it is focused by the focusing lens 5 to act on the workpiece to be processed, completing the laser etching of the workpiece. Laser etching has high etching precision, good stability, and a simple process. It can form field emission cathodes with good morphological consistency and excellent uniformity, making it suitable for large-scale production of field emission cathodes.

[0045] Specifically, the beam expander can expand the laser emitted by the laser 1 to form an expanded laser, increase the diameter of the light beam, and reduce the beam divergence, which helps subsequent modulation by the spatial light modulator 3. The spatial light modulator 3 can modulate and split the expanded laser according to a preset pattern to form a modulated laser. After scaling by the optical scaling system 4, the modulated laser forms a scaled laser with a suitable pixel size, and then forms a focused laser by the focusing objective 5, and then performs laser etching on the workpiece to be processed. Compared with the related art wet etching, oxygen plasma oxidation or argon plasma dry etching, oxygen plasma oxidation combined with wet etching of the oxide layer with hydrochloric acid, electrochemical etching and other processes, laser etching has higher precision, good stability, simple process, and can form a field emission cathode with good topography consistency and excellent uniformity, which is suitable for large-scale production and processing of field emission cathodes.

[0046] In some embodiments, as shown in Figure 1 The processing device of the field emission cathode further includes a 1 / 2 glass 7 and a 1 / 4 glass 8. The 1 / 2 glass 7 is arranged between the output end of the beam expander and the receiving end of the spatial light modulator 3, and the 1 / 4 glass 8 is arranged between the output end of the spatial light modulator 3 and the receiving end of the optical scaling system 4.

[0047] The 1 / 2 glass 7 can convert the incident linearly polarized light into circularly polarized light, i.e., convert the expanded laser from linearly polarized light into circularly polarized light. The circularly polarized light rotates continuously during propagation and has rotational symmetry, so that when it enters the spatial light modulator 3, it is not affected by the slight deviation of the internal light path or elements of the spatial light modulator 3, thereby ensuring the stability and reliability of the transmission of the expanded laser. In addition, the use of two polarization states (left-handed and right-handed) of circularly polarized light helps to achieve multiple modulation modes.

[0048] The 1 / 4 glass 8 can convert the incident circularly polarized light into linearly polarized light, i.e., convert the modulated laser output by the spatial light modulator 3 from circularly polarized light into linearly polarized light. Linearly polarized light has directional properties of electric field vectors, which can produce directional ablation on materials, thereby enabling more precise control of the direction and depth of ablation, helping to achieve high-precision etching and ensure the topography consistency of the field emission cathode.

[0049] In some embodiments, as shown in Figure 1 The processing device of the field emission cathode further includes a light splitting prism 9 and a power receiving feedback device 10. The light splitting prism 9 is arranged between the 1 / 2 glass 7 and the receiving end of the spatial light modulator 3. The first light beam output by the light splitting prism 9 enters the spatial light modulator 3, and the second light beam output by the light splitting prism 9 enters the power receiving feedback device 10.

[0050] The beam expander laser can be split into a first light beam and a second light beam by the light splitting prism 9, wherein the first light beam can be incident on the spatial light modulator 3 to perform laser etching on the workpiece to be processed after modulation, scaling and focusing, and the second light beam can be transmitted to the power receiving feedback device 10, which can monitor the power of the beam expander laser, and then adjust the laser 1 to ensure the stability of the beam expander laser incident on the spatial light modulator 3 and the accuracy and consistency of the field emission cathode.

[0051] The light splitting prism 9 can be a PBS light splitting prism 9 (polarization light splitting prism 9) that can split the incident laser into two mutually perpendicular light beams, one of which is reflected and the other of which is transmitted. For example, after the beam expander laser passes through the PBS light splitting prism 9, 90% of the energy of the beam expander laser is reflected to the spatial light modulator 3 to ensure that the laser etching has sufficient energy, and 10% of the energy is transmitted to the power receiving feedback device 10 to adjust the power of the laser 1 according to the monitoring situation to ensure the stability of the beam expander laser incident on the spatial light modulator 3.

[0052] In some embodiments, as shown in Figure 1 The field emission cathode processing device further includes a moving platform 6. The moving platform 6 is arranged at the output end of the focusing objective lens 5 and is used to carry the workpiece to be processed and adjust the relative position between the workpiece to be processed and the focusing objective lens 5.

[0053] The moving platform 6 can carry the workpiece to be processed and adjust the relative position between the workpiece to be processed and the focusing objective lens 5, thereby achieving the purpose of laser etching on different positions of the workpiece to be processed.

[0054] The moving platform 6 can be a three-axis moving platform 6 that can be adjusted in the forward-backward direction, the upward-downward direction and the left-right direction, and can drive the workpiece to be processed to move in the forward-backward direction, the upward-downward direction and the left-right direction to perform laser etching on different positions of the workpiece to be processed.

[0055] For example, the moving platform 6 can be a PI company's L-306.011112 precision Z direction displacement table, which has a Z axis effective stroke of 13 mm, a minimum displacement of 0.1 μm and a one-way repeat accuracy of 0.1 μm, and can meet the processing accuracy requirements of the field emission cathode.

[0056] In some embodiments, as shown in Figure 1 The field emission cathode processing device further includes a first mirror 11 and a second mirror 12. The first mirror 11 is arranged between the output end of the beam expander and the receiving end of the light splitting prism 9, and the second mirror 12 is arranged between the output end of the spatial light modulator 3 and the receiving end of the optical scaling system 4.

[0057] The laser beam can be reflected by the first and second reflecting mirrors, thereby changing the direction of the laser beam. By properly setting the position and angle of the first reflecting mirror 11 and the second reflecting mirror 12, it is helpful to arrange the components in the field emission cathode processing device and reduce the space occupation.

[0058] In some embodiments, laser 1 includes a green femtosecond laser 1. The repetition rate of laser 1 is ≤1MHz, the pulse width is <250fs, and the average power is ≤20W.

[0059] The green femtosecond laser has an ultrashort pulse width and a high repetition rate, which can release extremely high energy in a very short time, thus helping to achieve fine and efficient processing.

[0060] For example, laser 1 can be a GS-FGN20 series 515nm green femtosecond laser from Wuhan Raycus Fiber Laser Technologies Co., Ltd.

[0061] In some embodiments, such as Figure 1 As shown, the optical scaling system 4 includes a first lens 41 and a second lens 42. The first lens 41 is disposed between the output end of the spatial light modulator 3 and the receiving end of the focusing objective lens 5, and the second lens 42 is disposed between the first lens 41 and the receiving end of the focusing objective lens 5. The focal length of the first lens 41 is smaller than the focal length of the second lens 42.

[0062] By setting the position and focal length of the first lens 41 and the second lens 42, the pixel size of the modulated laser emitted by the spatial light modulator 3 can be reduced, thereby ensuring the precision of laser etching and meeting the processing requirements of the field emission cathode.

[0063] In some embodiments, the spatial light modulator 3 has a wavelength range of 532nm±50nm, a pixel size of 1920×1200, and a pixel size of 7.8μm.

[0064] For example, the spatial light modulator 3 can be Santec's SLM-310-G spatial light modulator 3.

[0065] In some embodiments, the beam expander is a 3x beam expander. For example, the laser emitted by laser 1 has a diameter of 2 mm, and after being expanded by the beam expander, it can form a beam expanded laser with a diameter of 6 mm.

[0066] In some embodiments, the focal length of the first lens 41 in the optical scaling system 4 is 25 mm, and the focal length of the second lens 42 is 190 mm. That is, the scaling factor of the optical scaling system 4 is approximately 7.6 times. The pixel size of the modulated laser emitted by the spatial light modulator 3 is 7.8 μm. After being scaled by the optical scaling system 4, a pattern with a pixel size of 1.03 μm is formed, thereby achieving micron-level laser etching.

[0067] In some embodiments, the numerical aperture of the focusing objective 5 is 2, the focal length is 2 mm, the wavelength is 515 nm, the field diameter is 6.5 mm, and the resolution is 0.24 μm, thereby ensuring good focusing effect.

[0068] In a second aspect, the embodiments of the present application also provide a field emission cathode 20, which is prepared by the processing device of the field emission cathode or the processing method of the field emission cathode as described above.

[0069] Through the processing device of the field emission cathode or the processing method of the field emission cathode, the field emission cathode can be prepared by laser etching, thereby ensuring the consistency and uniformity of the morphology of the field emission cathode 20 and improving the performance of the field emission cathode.

[0070] In some embodiments, the material of the field emission cathode 20 is lanthanum hexaboride. Lanthanum hexaboride has stable physical and chemical properties and hard and brittle characteristics, which leads to a greater difficulty in processing. Through the processing device of the field emission cathode or the processing method of the field emission cathode provided by the present application, the processing of the lanthanum hexaboride field emission cathode can be realized by the laser etching method. The laser etching has high precision and good stability, and the process is simple, which is helpful to form the field emission cathode 20 with good consistency and excellent uniformity, and is suitable for large-scale production and processing of the field emission cathode 20.

[0071] Since lanthanum hexaboride has the advantages of low escape power, high melting point, low evaporation rate, stable chemical properties, strong ion bombardment resistance, and good thermal conductivity, the performance of the field emission cathode can be improved.

[0072] In some embodiments, as shown in FIG. 2, Figure 2 The height of the conical structure 21 is 3 μm, the bottom radius is 4 μm; and / or, the spacing between adjacent conical structures 21 is 8 μm; and / or, the array density of the conical structure 21 is 2×10 6 tips / cm 2 .

[0073] By setting the parameters of the field emission cathode 20, the electric field can be more effectively concentrated, thereby reducing the threshold voltage of electron emission, ensuring the stability of the structure, reducing the electric field interference between adjacent conical structures 21, and having higher electron emission capacity and more uniform electron beam distribution.

[0074] It can be understood that the field emission cathode can also be other structures, and the parameters can also be adjusted according to specific needs.

[0075] In order to make the embodiments of the present application clearer, the processing method of the field emission cathode is exemplarily illustrated. Based on the processing device of the field emission cathode as described above, the processing method of the field emission cathode comprises the following steps:

[0076] S1, placing the workpiece to be processed at the output end of the focusing objective 5;

[0077] S2, controlling the laser 1 to emit laser, and the beam expander to expand the laser to form expanded laser;

[0078] S3, the spatial light modulator 3 converts the expanded laser into modulated laser according to the preset pattern;

[0079] S4, the optical zoom system 4 adjusts the pixel size of the modulated laser to form zoomed laser;

[0080] S5, the focusing objective 5 converts the zoomed laser into focused laser, and makes the focused laser etch the surface of the workpiece to be processed to obtain the field emission cathode.

[0081] S1, placing the workpiece to be processed at the output end of the focusing objective 5, comprises:

[0082] Placing the workpiece to be processed on the moving platform 6 at the output end of the focusing objective 5.

[0083] By placing the workpiece to be processed on the moving platform 6, the relative position between the workpiece to be processed and the focusing objective 5 can be adjusted by the moving platform 6, so as to realize the purpose of laser etching different positions in the workpiece to be processed.

[0084] S5, the focusing objective 5 converts the zoomed laser into focused laser, and makes the focused laser etch the surface of the workpiece to be processed to obtain the field emission cathode.

[0085] Adjusting the relative position of the workpiece to be processed and the focusing objective 5 for re-etching.

[0086] That is to say, after etching the workpiece to be processed, the position is replaced, and other positions of the workpiece to be processed are etched, so as to form a field emission cathode array with appropriate size on the surface of the workpiece to be processed.

[0087] S5, the focusing objective 5 converts the zoomed laser into focused laser, and makes the focused laser etch the surface of the workpiece to be processed to obtain the field emission cathode.

[0088] Exemplarily, when a lanthanum hexaboride substrate with a thickness of 5 μm is processed to form a field emission cathode with a height of 3 μm, the lanthanum hexaboride substrate can be laser etched by moving up one layer every 0.1 μm. By adjusting the preset pattern of each layer of etching, the morphology of the formed field emission cathode can be controlled, and the field emission cathode with a height of 3 μm can be etched by moving up 30 layers in total.

[0089] The above has introduced the embodiments of the present application in detail, and the principles and implementation manners of the present application have been described by applying specific examples; the above embodiment explanations are only for helping to understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application ranges will have changes; in conclusion, the content of the specification should not be understood as limiting the present application.

Claims

1. A processing apparatus of a field emission cathode, characterized by comprising: The processing device comprises: a laser for emitting laser light; a beam expander arranged at an output end of the laser for converting the laser light into expanded laser light; a spatial light modulator arranged at an output end of the beam expander for converting the expanded laser light into modulated laser light according to a preset pattern; an optical zoom system arranged at an output end of the spatial light modulator for converting the modulated laser light into zoomed laser light; a focusing objective arranged at an output end of the optical zoom system for converting the zoomed laser light into focused laser light.

2. The processing apparatus of a field emission cathode according to claim 1, wherein The processing device further comprises a 1 / 2 glass and a 1 / 4 glass; the 1 / 2 glass is arranged between the output end of the beam expander and the receiving end of the spatial light modulator; the 1 / 4 glass is arranged between the output end of the spatial light modulator and the receiving end of the optical zoom system.

3. The processing apparatus of a field emission cathode according to claim 2, wherein The processing device further comprises a light splitting prism and a power receiving feedback device; the light splitting prism is arranged between the 1 / 2 glass and the receiving end of the spatial light modulator; a first light beam output by the light splitting prism enters the spatial light modulator, and a second light beam output by the light splitting prism enters the power receiving feedback device.

4. The processing apparatus of a field emission cathode according to claim 1, wherein The processing device further comprises a moving platform; the moving platform is arranged at the output end of the focusing objective for carrying a workpiece to be processed and adjusting the relative position between the workpiece to be processed and the focusing objective.

5. The processing apparatus of a field emission cathode according to claim 3, wherein The processing device further comprises a first mirror and a second mirror; the first mirror is arranged between the output end of the beam expander and the receiving end of the light splitting prism; the second mirror is arranged between the output end of the spatial light modulator and the receiving end of the optical zoom system.

6. The processing apparatus of a field emission cathode according to any one of claims 1 to 5, wherein The laser comprises a green femtosecond laser; the repetition frequency of the laser is ≤1 MHz, the pulse width is <250 fs, and the average power is ≤20 W.

7. The processing apparatus of a field emission cathode according to any one of claims 1 to 5, wherein The optical zoom system comprises a first lens and a second lens; the first lens is arranged between the output end of the spatial light modulator and the receiving end of the focusing objective; the second lens is arranged between the first lens and the receiving end of the focusing objective; wherein the focal length of the first lens is smaller than the focal length of the second lens.

8. The processing apparatus of the field emission cathode according to any one of claims 1 to 5, wherein The wavelength range of the spatial light modulator is 532 nm±50 nm, and the pixel size is 7.8 μm; and / or, the numerical aperture of the focusing objective is 2, the focal length is 2 mm, and the resolution is 0.24 μm.

9. A field emission cathode, characterized by The processing device is made by using the field emission cathode according to any one of claims 1-6.

10. The field emission cathode of claim 9, wherein the carbon nanotube is a single-walled carbon nanotube. The material of the field emission cathode is lanthanum hexaboride.

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