Electron beam electromagnetic restraint system for vacuum electron gun coating machine

Abstract

The invention relates to the technical field of vacuum coating, in particular to an electron beam electromagnetic restraint system for a vacuum electron gun coating machine, which comprises an outer focusing coil, an inner focusing coil, an insulating component, a cooling structure, a monitoring component, a control module and a low-temperature drift power supply module, the outer focusing coil and the inner focusing coil are coaxially nested and form a multi-layer coaxial solenoid coil, a cooling structure is arranged between the two coils, and the whole coils and the cooling structure are packaged in a matched manner; the monitoring assembly is electrically connected with the control module, the control module is electrically connected with the outer focusing coil, the inner focusing coil and the low-temperature-drift power module, and the low-temperature-drift power module supplies power to the coils and the control module. Reverse current is introduced into the outer focusing coil and the inner focusing coil to generate a gradient magnetic field, and electron beam regulation and control are cooperatively realized; the monitoring assembly collects related parameters and transmits the parameters to the control module, the control module calculates the parameters and then adjusts the current of the two coils, and vertical incidence and high-energy focusing of the electron beam are achieved.

Description

Technical Field

[0001] This invention relates to the field of vacuum coating technology, and in particular to an electron beam electromagnetic confinement system for a vacuum electron gun coating machine. Background Technology

[0002] In the field of vacuum electron gun coating technology, vacuum coating has a wide range of applications due to its advantage of being able to deposit thin films of metals, alloys, compounds, and some organic polymers on the surfaces of various substrates such as metals, semiconductors, insulators, and plastics. However, existing electron gun coating machines generally use permanent magnet deflection or single electromagnetic scanning technology, which has the following technical problems:

[0003] Traditional electron guns often employ a fixed deflection angle of 180° or 270°, which prevents the electron beam from striking the target surface perpendicularly. The incident angle often deviates from the normal by more than 10°, and the beam divergence is severe (e.g., the beam diameter of a certain type of equipment reaches φ25mm or more). The energy density is less than 0.5kW / mm², directly leading to a 15-20% decrease in the material evaporation rate.

[0004] Scattered electrons bombarding components around the crucible can cause localized temperature rises exceeding 300°C, leading to vacuum seal failure and material release, causing the system vacuum level to drop from 10⁻⁻⁶. 4 Pa deteriorates to the order of 10⁻²Pa, further affecting the coating quality;

[0005] Non-perpendicular incident light can lead to poor orientation of the evaporating particle stream. When coating large-area substrates (>1m²), the thickness deviation between the edge and the center can reach more than 30%.

[0006] Beam divergence increases the probability of collisions with residual gas molecules, accelerating the oxidation failure of the cathode filament. When the vacuum level is below 5×10⁻³Pa, the tungsten filament life drops sharply from 500 hours to less than 200 hours.

[0007] Furthermore, existing technologies rely on permanent magnet deflection systems, which, due to their fixed magnetic field strength (0.1-0.3T), cannot compensate for space charge effects in real time. Moreover, the fixed deflection plane makes it difficult to adapt to multi-crucible dynamic coating processes. Even increasing the number of magnetic poles will exacerbate magnetic field interference and worsen beam stability. Summary of the Invention

[0008] Based on this, it is necessary to provide an electron beam electromagnetic confinement system for a vacuum electron gun coating machine to address the above-mentioned technical problems. This system enables vertical electron beam incidence and high-energy focusing, fundamentally solving the core problems of large incident angle deviation and beam divergence in traditional technologies. Furthermore, the closed-loop control and stable power supply design improve beam stability, laying the foundation for subsequent coating uniformity and filament life extension.

[0009] This invention provides an electron beam electromagnetic confinement system for a vacuum electron gun coating machine, comprising: an outer focusing coil, an inner focusing coil, an insulating component, a cooling structure, a monitoring component, a control module, and a low-temperature drift power supply module;

[0010] The outer focusing coil and the inner focusing coil are coaxially nested, forming a multi-layer coaxial solenoid coil. A cooling structure is provided between the two coils, and the coil as a whole is encapsulated with the cooling structure. The monitoring component is electrically connected to the control module, which is electrically connected to the outer focusing coil, the inner focusing coil, and the cryogenic drift power supply module. The cryogenic drift power supply module supplies power to the coils and the control module. Reverse currents are passed through the outer focusing coil and the inner focusing coil to generate a gradient magnetic field, which works together to achieve electron beam control. The monitoring component collects relevant parameters and transmits them to the control module. The control module calculates the parameters and adjusts the current of the two coils to achieve vertical incidence and high-energy focusing of the electron beam.

[0011] In one embodiment, the insulating component is a ceramic insulating layer that fills the space between the outer focusing coil and the inner focusing coil to achieve insulation isolation between the coil layers.

[0012] In one embodiment, the cooling structure includes a cooling water tank and a water-cooled stainless steel sleeve. The cooling water tank is disposed between the outer focusing coil and the inner focusing coil, and the outer focusing coil and the inner focusing coil are integrally encapsulated in the water-cooled stainless steel sleeve.

[0013] In one embodiment, the external focusing coil has a saddle-shaped equidistant distribution structure, and the magnetic field it generates is used to capture leaked electrons over a large spatial range and suppress edge leakage magnetic field.

[0014] In one embodiment, the inner focusing coil is a double anti-rotation solenoid structure, and the magnetic field it generates is used to achieve high-energy focusing of the electron beam and incident angle calibration.

[0015] In one embodiment, the monitoring component includes a Faraday tube and a Hall sensor, both of which are signal-connected to the control module. The Faraday tube is used to monitor the beam current density distribution of the electron beam, and the Hall sensor is used to acquire the magnetic field strength.

[0016] In one embodiment, the control module is a dual-CPU system, used to receive and calculate the parameters transmitted by the Faraday cylinder and the Hall sensor, and change the magnetic field strength by adjusting the current magnitude of the outer focusing coil and the inner focusing coil.

[0017] In one embodiment, the control module uses a particle swarm optimization algorithm to calculate the optimal coil current combination and achieves precise control of the beam spot position by dynamically adjusting the current.

[0018] In one embodiment, the control module generates a spiral scanning trajectory based on the Lissajous figure principle to eliminate hot spots in the rectangular scanning corner area and reduce the heat-affected zone around the target material.

[0019] In one embodiment, the control module monitors the beam divergence angle of the electron beam in real time, and automatically starts the adaptive focusing compensation program when the beam divergence angle exceeds the preset range.

[0020] The aforementioned electron beam electromagnetic confinement system for a vacuum electron gun coating machine employs a coaxial nested structure of an outer focusing coil and an inner focusing coil. A reverse current is introduced to create a gradient magnetic field, and the Lorentz force is used to precisely control the electron beam trajectory. Then, beam current density and magnetic field strength parameters are collected by a monitoring component, and the current is dynamically adjusted after calculation by the control module, constructing a closed-loop control system of acquisition, calculation, and adjustment. Combined with a low-temperature drift power supply module, this ensures magnetic field stability. This system achieves vertical electron beam incidence and high-energy focusing, fundamentally solving the core problems of large incident angle deviation and beam divergence in traditional technologies. Furthermore, the closed-loop control and stable power supply design improve beam current stability, laying the foundation for subsequent coating uniformity and extended filament life. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 A partial structural schematic diagram of the electron beam electromagnetic confinement system provided by the present invention;

[0023] Figure 2 This is a schematic diagram of the module structure of the electron beam electromagnetic confinement system provided by the present invention.

[0024] Figure label:

[0025] 10. Crucible; 100. External focusing coil; 200. Internal focusing coil; 300. Cooling structure; 400. Control module; 500. Low-temperature drift power supply module; 600. Monitoring components. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The following is combined Figure 1 and Figure 2 The present invention describes an electron beam electromagnetic confinement system for a vacuum electron gun coating machine.

[0028] In one embodiment, an electron beam electromagnetic confinement system for a vacuum electron gun coating machine includes an outer focusing coil 100, an inner focusing coil 200, an insulating component, a cooling structure 300, a monitoring component 600, a control module 400, and a low-temperature drift power supply module 500. The outer focusing coil 100 and the inner focusing coil 200 are coaxially nested, forming a multi-layer coaxial solenoid coil, with the cooling structure 300 positioned between the two coils. The coil as a whole is encapsulated with the cooling structure 300. The monitoring component 600 and the control module 400... The control module 400 is electrically connected to the outer focusing coil 100, the inner focusing coil 200, and the cryogenic drift power supply module 500, respectively. The cryogenic drift power supply module 500 supplies power to the coils and the control module 400. The outer focusing coil 100 and the inner focusing coil 200 are supplied with reverse current to generate a gradient magnetic field, which works together to achieve electron beam control. The monitoring component 600 collects relevant parameters and transmits them to the control module 400. After calculating the parameters, the control module 400 adjusts the current of the two coils to achieve vertical incidence and high-energy focusing of the electron beam.

[0029] The aforementioned electron beam electromagnetic confinement system for a vacuum electron gun coating machine employs a coaxial nested structure of an outer focusing coil 100 and an inner focusing coil 200. A reverse current is introduced to form a gradient magnetic field, and the Lorentz force is used to precisely control the electron beam trajectory. Then, the monitoring component 600 collects beam current density and magnetic field strength parameters, which are then dynamically adjusted by the control module 400 after calculation, constructing a closed-loop control system for acquisition, calculation, and adjustment. Combined with a low-temperature drift power supply module 500, the stability of the magnetic field is ensured. This system achieves vertical electron beam incidence (vertical deviation ≤ 1.5°) and high-energy focusing (beam spot diameter ≤ φ1.5mm, energy density ≥ 8kW / mm²), fundamentally solving the core problems of large incident angle deviation and beam divergence in traditional technologies. Furthermore, the closed-loop control and stable power supply design improve beam current stability, laying the foundation for subsequent coating uniformity and extended filament life.

[0030] In one embodiment, the insulating component is a ceramic insulating layer that fills the space between the outer focusing coil 100 and the inner focusing coil 200 to achieve insulation isolation between the coil layers.

[0031] Specifically, the ceramic insulating layer (Al2O3) possesses high temperature resistance and excellent insulation properties. When filled between coil layers, it can block interlayer current conduction, avoiding short-circuit risks, while also withstanding temperature rises during coil operation. This ensures the reliability of interlayer insulation, prevents insulation failure under high-temperature environments, and, in conjunction with the cooling structure 300, achieves long-term stable system operation, avoiding magnetic field fluctuations caused by insulation problems.

[0032] In one embodiment, the cooling structure 300 includes a cooling water tank and a water-cooled stainless steel sleeve. The cooling water tank is disposed between the outer focusing coil 100 and the inner focusing coil 200, and the outer focusing coil 100 and the inner focusing coil 200 are encapsulated in the water-cooled stainless steel sleeve.

[0033] Specifically, a cooling water tank is located between the two coils, and the entire coil is encapsulated in a water-cooled stainless steel sleeve. Circulating cooling water quickly removes the heat generated by the coil during operation, suppressing the impact of temperature rise on coil resistance and magnetic field strength. This effectively controls coil temperature rise, avoids performance degradation caused by prolonged high temperatures, reduces the heat load on surrounding components (heat-affected zone reduced by 70%), alleviates vacuum seal failure and material outgassing issues, maintains stable system vacuum, and extends coil lifespan.

[0034] In one embodiment, the external focusing coil 100 has a saddle-shaped equidistant distribution structure, and the magnetic field it generates is used to capture leaked electrons over a large spatial range and suppress edge leakage magnetic field.

[0035] Specifically, the external focusing coil 100 adopts a saddle-shaped equidistant distribution structure, and the magnetic field it generates is in a ring-shaped confinement form, which can cover a large area around the crucible 10, capture leaking electrons and suppress edge leakage magnetic field, and reduce the bombardment of non-target areas by scattered electrons. This significantly reduces the thermal shock of leaking electrons to the components around the crucible 10, further shrinks the heat-affected zone, and, together with the cooling structure 300, keeps the local temperature rise within a safe range, avoids vacuum deterioration, and at the same time reduces energy waste and improves energy utilization efficiency.

[0036] In one embodiment, the inner focusing coil 200 is a double anti-rotation solenoid structure, and the magnetic field it generates is used to achieve high-energy focusing of the electron beam and incident angle calibration.

[0037] Specifically, the inner focusing coil 200 is a double anti-rotation solenoid structure. After current is applied, it generates an axial compression magnetic field, which uses the magnetic field gradient to form a centripetal focusing force on the electron beam. At the same time, it calibrates the trajectory of the electron beam, ensuring that it is incident on the target along the normal direction. This achieves high-energy focusing of the electron beam and precise calibration of the incident angle, compressing the beam spot diameter to below φ1.5mm and increasing the energy density to above 8kW / mm², solving the problem of insufficient energy density in traditional technologies. The vertical incident design enhances the directionality of the evaporation particle stream, improving the uniformity of the coating.

[0038] In one embodiment, the monitoring component 600 includes a Faraday cylinder and a Hall sensor. Both the Faraday cylinder and the Hall sensor are connected to the control module 400 via signals. The Faraday cylinder is used to monitor the beam current density distribution of the electron beam, and the Hall sensor is used to acquire the magnetic field strength.

[0039] Specifically, the Faraday lamp collects electron beam current signals to accurately monitor beam current density distribution; the Hall sensor, based on the Hall effect, acquires magnetic field strength data in real time. Both convert parameters into electrical signals and transmit them to the control module 400, providing data support for closed-loop control. This achieves real-time and accurate acquisition of beam current and magnetic field parameters, avoiding the blind control defects of traditional technologies. The control module 400 can dynamically respond to parameter changes, providing a reliable basis for current adjustment and ensuring beam stability and focusing accuracy.

[0040] In one embodiment, the control module 400 is a dual-CPU system used to receive and calculate the parameters transmitted by the Faraday cylinder and the Hall sensor, and to change the magnetic field strength by adjusting the current magnitude of the outer focusing coil 100 and the inner focusing coil 200.

[0041] Specifically, the dual-CPU system possesses parallel computing capabilities, enabling it to quickly resolve parameters transmitted by the Alfred tube and Hall sensor. Based on a preset algorithm, it generates current adjustment commands, dynamically adjusting the magnetic field strength and shape by changing the current in the outer and inner focusing coils 200. This improves parameter calculation and command response speed, achieving precise and rapid adjustment of the magnetic field strength with a beam spot position accuracy of ±0.1mm. It solves the problems of poor beam stability and adjustment lag in traditional technologies, adapting to the requirements of dynamic coating processes.

[0042] In one embodiment, the control module 400 uses a particle swarm optimization algorithm to calculate the optimal coil current combination and achieves precise control of the beam spot position by dynamically adjusting the current.

[0043] Specifically, the particle swarm optimization algorithm simulates the cooperative search behavior of a swarm of particles to rapidly iteratively calculate the optimal coil current combination for different coating conditions, ensuring a precise match between the magnetic field configuration and electron beam control requirements. Optimizing the coil current distribution further improves the beam focusing accuracy and stability, enabling the electron beam to maintain optimal focusing under different target materials and substrate sizes, broadening the equipment's applicability, and simultaneously improving energy utilization efficiency.

[0044] In one embodiment, the control module 400 generates a spiral scanning trajectory based on the Lissajous figure principle to eliminate hot spots in the rectangular scanning corner area and reduce the heat-affected zone around the target material.

[0045] Specifically, based on the Lissajous figure principle, the control module 400 generates a spiral scanning trajectory, causing the electron beam to move in a continuous spiral motion on the target surface. This avoids electron accumulation in the corner areas caused by rectangular scanning and eliminates local hot spots. It also evenly distributes electron beam energy, preventing localized overheating damage to the target and reducing film defects caused by thermal stress. Simultaneously, it reduces the generation of scattered electrons, extending filament life to over 300 hours and improving the stability of the coating process and product yield.

[0046] In one embodiment, the control module 400 monitors the beam divergence angle of the electron beam in real time, and automatically starts the adaptive focusing compensation program when the beam divergence angle exceeds the preset range.

[0047] Specifically, the control module 400 monitors the electron beam divergence angle in real time. When the divergence angle α > 5°, it automatically initiates an adaptive focusing compensation program. This program adjusts the current in the inner focusing coil 200 to enhance the focusing magnetic field and correct the electron beam trajectory. Dynamically compensating for beam divergence prevents spot enlargement and energy density reduction, ensuring stable beam conditions during coating and preventing issues such as poor coating uniformity and energy waste caused by beam divergence, thus guaranteeing consistent product quality.

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

[0049] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. An electron beam electromagnetic confinement system for a vacuum electron gun coating machine, characterized in that, include: External focusing coil, internal focusing coil, insulation components, cooling structure, monitoring components, control module, and low-temperature drift power supply module; The outer focusing coil and the inner focusing coil are coaxially nested, forming a multi-layer coaxial solenoid coil. A cooling structure is provided between the two coils, and the coil as a whole is encapsulated with the cooling structure. The monitoring component is electrically connected to the control module, which is electrically connected to the outer focusing coil, the inner focusing coil, and the cryogenic drift power supply module. The cryogenic drift power supply module supplies power to the coils and the control module. Reverse currents are passed through the outer focusing coil and the inner focusing coil to generate a gradient magnetic field, which works together to achieve electron beam control. The monitoring component collects relevant parameters and transmits them to the control module. The control module calculates the parameters and adjusts the current of the two coils to achieve vertical incidence and high-energy focusing of the electron beam.

2. The electron beam electromagnetic confinement system for a vacuum electron gun coating machine according to claim 1, characterized in that, The insulating component is a ceramic insulating layer that fills the space between the outer focusing coil and the inner focusing coil to achieve insulation isolation between the coil layers.

3. The electron beam electromagnetic confinement system for a vacuum electron gun coating machine according to claim 2, characterized in that, The cooling structure includes a cooling water tank and a water-cooled stainless steel sleeve. The cooling water tank is disposed between the outer focusing coil and the inner focusing coil. The outer focusing coil and the inner focusing coil are encapsulated together in the water-cooled stainless steel sleeve.

4. The electron beam electromagnetic confinement system for a vacuum electron gun coating machine according to claim 3, characterized in that, The external focusing coil has a saddle-shaped equidistant distribution structure, and the magnetic field it generates is used to capture leaked electrons over a large area of ​​space and suppress edge leakage magnetic field.

5. The electron beam electromagnetic confinement system for a vacuum electron gun coating machine according to claim 4, characterized in that, The inner focusing coil has a double anti-rotation solenoid structure, and the magnetic field it generates is used to achieve high-energy focusing of the electron beam and calibration of the incident angle.

6. The electron beam electromagnetic confinement system for a vacuum electron gun coating machine according to claim 5, characterized in that, The monitoring component includes a Faraday tube and a Hall sensor. Both the Faraday tube and the Hall sensor are connected to the control module via signals. The Faraday tube is used to monitor the beam current density distribution of the electron beam, and the Hall sensor is used to acquire the magnetic field strength.

7. The electron beam electromagnetic confinement system for a vacuum electron gun coating machine according to claim 6, characterized in that, The control module is a dual-CPU system, used to receive and calculate the parameters transmitted by the Faraday cylinder and the Hall sensor, and to change the magnetic field strength by adjusting the current magnitude of the outer focusing coil and the inner focusing coil.

8. The electron beam electromagnetic confinement system for a vacuum electron gun coating machine according to claim 7, characterized in that, The control module uses a particle swarm optimization algorithm to calculate the optimal coil current combination and achieves precise control of the beam spot position by dynamically adjusting the current.

9. The electron beam electromagnetic confinement system for a vacuum electron gun coating machine according to claim 8, characterized in that, The control module generates a spiral scanning trajectory based on the Lissajous figure principle to eliminate hot spots in the rectangular scanning corner area and reduce the heat-affected zone around the target material.

10. The electron beam electromagnetic confinement system for a vacuum electron gun coating machine according to claim 9, characterized in that, The control module monitors the beam divergence angle of the electron beam in real time. When the beam divergence angle exceeds the preset range, it automatically starts the adaptive focusing compensation program.

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