Microchannel plate manufacturing method based on mold pouring method and microchannel plate

Abstract

The invention relates to a micro-channel plate manufacturing method based on a mold pouring method and a micro-channel plate. The method comprises the steps that a silicon microchannel array substrate is placed on a metal mold material, and holes of the silicon microchannel array substrate face downwards; based on a crucible and a vacuum hot melting filling device, liquefying a metal mold material and filling the metal mold material into the silicon micro-channel array substrate; cooling to realize metal curing to obtain a metal mold precursor, and corroding silicon to obtain a metal mold; putting the high borosilicate glass material and the metal mold into a crucible, and filling the high borosilicate glass material into the metal mold based on a vacuum hot melting filling device; cooling to obtain a glass-metal complex, and corroding a metal material to obtain a micro-channel plate substrate; carrying out hydroxylation treatment; and preparing a dynode on the micro-channel plate substrate, and performing annealing treatment to obtain the micro-channel plate. The microchannel plate with a high softening point and high purity can be manufactured, the yield is high, noise is low, exhaust in the channel is sufficient, and the service life of the image tube is prolonged.

Description

Technical Field

[0001] This disclosure relates to the field of electron multipliers, and in particular to a method for fabricating microchannel plates based on a mold casting method and a microchannel plate. Background Technology

[0002] A microchannel plate (MCP) is a high-gain electron multiplier composed of millions of microchannels arranged in a two-dimensional array. Each channel is an independent electron multiplier, giving it advantages such as high gain, low noise, and fast response. MCPs have wide applications in low-light night vision, medical imaging, photomultiplier tubes, X-ray image intensifiers, ultraviolet astronomy, and nuclear physics. When an MCP is in operation, a working voltage is applied to its terminals, forming a uniform electric field distributed along the channel axis. The inner walls of the channels have the ability to emit secondary electrons. When low-energy electrons or photons enter the channel from the input terminal of the MCP at a certain angle and with a certain energy, they collide with the inner walls of the channel, exciting secondary electrons. Under the influence of the electric field, the secondary electrons continuously accelerate forward, gradually exciting more new secondary electrons, thus achieving the electron multiplication function.

[0003] Traditional MCPs are manufactured using multi-fiber drawing technology from lead silicate glass. The process mainly includes: drawing lead glass fibers into monofilaments, arranging them, drawing multifilaments, secondary arranging, slicing, polishing, etching, hydrogen reduction, and electrode deposition. Methods to improve the performance of traditional MCPs include adjusting the glass ratio in the sheath and optimizing subsequent manufacturing processes. In the early stages of technological development, these methods significantly improved the lifespan and current gain of MCPs. However, as traditional MCPs have evolved to modern times, their performance is limited by the physical properties of the materials and the manufacturing process, making further improvements difficult. Traditional methods of MCP fabrication involve a strict matching issue between the core rod and the sheath glass. Matching the rod and tube materials involves two key aspects: first, the sheath glass tube and the soluble glass core rod should have similar softening temperatures and coefficients of expansion; second, they must meet the requirements of subsequent processes such as polishing, etching, and hydrogen reduction. This severely restricts the selection of MCP materials, and the etching process of the core limits the aspect ratio of the MCP to no more than 100.

[0004] Traditional glass microchannel plates are limited by manufacturing technology and cannot produce MCPs with high softening point and high purity. They also have disadvantages such as low yield, high noise, and insufficient venting within the channels. Summary of the Invention

[0005] Therefore, it is necessary to provide a microchannel plate fabrication method based on mold casting and a microchannel plate to address the above problems.

[0006] To solve the above problems, the present disclosure adopts the following technical solution: In a first aspect, this disclosure provides a method for fabricating microchannel plates based on a mold casting method, comprising the following steps: Step 1: Place the metal mold material in a crucible, place the silicon microchannel array substrate on the metal mold material, and ensure that the holes of the silicon microchannel array substrate face downwards; Step 2: Place the crucible into a vacuum hot melt filling device, and use the vacuum hot melt filling device to liquefy the metal mold material and fill it into the silicon microchannel array substrate; after the vacuum hot melt filling device cools down to solidify the metal, the metal mold precursor is obtained. Step 3: Etch the silicon in the metal mold precursor to obtain the metal mold; Step 4: Place the high borosilicate glass material and the metal mold into a crucible, and then place the crucible into a vacuum hot-melt filling device. The high borosilicate glass material is then filled into the metal mold using the vacuum hot-melt filling device. Cool the material to obtain a glass-metal composite. Etch away all the metal material in the glass-metal composite to obtain the microchannel plate substrate. Step 5: Hydroxylate the microchannel plate substrate; Step 6: Prepare a darad on the microchannel plate substrate using atomic layer deposition, and then perform annealing treatment to obtain the microchannel plate.

[0007] In a preferred embodiment, the step of enlarging the diameter of the blind vias is further included before placing the silicon microchannel array substrate on the metal mold material.

[0008] In a preferred embodiment, step two specifically involves: placing the crucible into a vacuum hot melt filling device, heating the vacuum hot melt filling device to a temperature higher than the melting point of the metal mold material, maintaining this temperature while restoring the gas pressure inside the vacuum hot melt filling device from vacuum to atmospheric pressure, so as to liquefy the metal mold material and fill it into the silicon microchannel array substrate; after the vacuum hot melt filling device cools down to achieve metal solidification, a metal mold precursor is obtained.

[0009] In a preferred embodiment, the vacuum degree in step two is less than 10 Pa; the heating of the vacuum hot melt filling device to a temperature higher than the metal melting point of the metal mold material is specifically: heating the vacuum hot melt filling device to a temperature 50-100°C higher than the metal melting point of the metal mold material.

[0010] In a preferred embodiment, step three specifically involves: heating a KOH solution with a concentration of 28-32 wt% in a water bath at 75-85°C, immersing the metal mold precursor in the KOH solution, etching silicon, obtaining a metal mold corresponding to the silicon microchannel array substrate after etching, rinsing the metal mold with deionized water and drying it.

[0011] In a preferred embodiment, the process of filling high borosilicate glass material into a metal mold using a vacuum hot-melt filling device specifically involves: heating the vacuum hot-melt filling device to a temperature higher than the softening point of the high borosilicate glass material, maintaining this temperature while restoring the air pressure inside the vacuum hot-melt filling device from vacuum to atmospheric pressure, thereby filling the high borosilicate glass material into the metal mold.

[0012] In a preferred embodiment, the vacuum degree in step four is less than 10 Pa; heating the vacuum hot-melt filling device to a temperature higher than the softening point of the borosilicate glass material specifically means heating the vacuum hot-melt filling device to a temperature at least 200°C higher than the softening point of the borosilicate glass material.

[0013] In a preferred embodiment, step five specifically involves: ultrasonically cleaning the microchannel plate substrate with deionized water, immersing it in a piranha solution after cleaning, heating it in a 75-85°C water bath for 15-25 minutes, removing the microchannel plate substrate, rinsing it with deionized water in an ultrasonic cleaner, and drying it with nitrogen gas.

[0014] In a preferred embodiment, the fabrication of the darad electrode on the microchannel plate substrate using atomic layer deposition includes fabricating a conductive layer and an emission layer, wherein the conductive layer comprises a tungsten thin film and an aluminum oxide thin film, and the emission layer comprises an aluminum oxide thin film. The steps for preparing the aluminum oxide thin film by atomic layer deposition include: introducing a first precursor, trimethylaluminum, which undergoes a chemical adsorption reaction with hydroxyl groups; purging with an inert gas; introducing a second precursor, water vapor, to generate aluminum oxide; and purging with an inert gas. The steps for preparing the tungsten thin film by atomic layer deposition include: introducing a third precursor, tungsten hexafluoride, where fluoride ions are chemically adsorbed onto the active sites; purging with an inert gas; introducing a fourth precursor, silane, to reduce tungsten ions to tungsten atoms; and purging with an inert gas. The annealing process includes: placing the microchannel plate substrate with danodic electrodes in a tube furnace, using nitrogen or argon as a protective atmosphere, heating the substrate to 500-700°C at a rate of 5-10°C / min, and annealing at a constant temperature for 2-10 hours.

[0015] Secondly, this disclosure provides a microchannel plate, which is fabricated using the microchannel plate fabrication method based on the mold casting method described in the first aspect.

[0016] The aforementioned microchannel plate fabrication method and microchannel plate based on the mold casting method involve placing a silicon microchannel array substrate on a metal mold material with the holes of the silicon microchannel array substrate facing downwards. A vacuum hot-melt filling device is used to fully fill the silicon microchannel array substrate with the metal mold material. A metal mold is obtained by etching silicon. High borosilicate glass material and the metal mold are placed in the vacuum hot-melt filling device to fill the metal mold with the high borosilicate glass material. The metal material is then etched away to obtain the microchannel plate substrate. The microchannel plate substrate is then subjected to hydroxylation treatment. Finally, the microchannel plate is obtained through operations such as the preparation of a dynamo electrode. This design can produce microchannel plates with high softening point and high purity, with high yield, low noise, and sufficient venting within the channels. Attached Figure Description

[0017] Figure 1 This is a schematic flowchart of a microchannel plate fabrication method based on mold casting in one embodiment of the present disclosure. Figure 2 This is a perspective view of a silicon microchannel array substrate at one angle in one embodiment of the present disclosure; Figure 3 This is a perspective view of the silicon microchannel array substrate from another angle in one embodiment of this disclosure; Figure 4 This is a three-dimensional cross-sectional view of a silicon microchannel array substrate in one embodiment of the present disclosure; Figure 5 This is a schematic diagram showing the positional relationship between the silicon microchannel array substrate and the metal mold material in one embodiment of this disclosure; Figure 6 This is a schematic diagram of a conventional vacuum hot melt filling apparatus used in one embodiment of this disclosure; Figure 7 This is a schematic diagram of a silicon microchannel array substrate and a molten metal mold material in one embodiment of the present disclosure; Figure 8 This is a schematic diagram of a metal mold prepared in one embodiment of the present disclosure.

[0018] Among them, 1. Silicon microchannel array substrate; 2. Blind via; 3. Vacuum tube furnace; 4. Crucible; 5. High-purity nitrogen cylinder; 6. Valve; 7. Vacuum pump; 8. Metal mold material; 9. Metal mold. Detailed Implementation

[0019] The technical solutions of this disclosure will now be described in detail with reference to the accompanying drawings and preferred embodiments.

[0020] It should be noted that the use of terms such as "first" and "second" in this disclosure is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0021] See Figure 1 This example provides a method for fabricating microchannel plates based on the mold casting method, including: Step 1: Place the metal mold material 8 in the crucible 4, place the silicon microchannel array substrate 1 on the metal mold material 8, and make sure the holes of the silicon microchannel array substrate 1 face downwards. Step 2: Place the crucible 4 into the vacuum hot melt filling device, and use the vacuum hot melt filling device to liquefy the metal mold material 8 and fill it into the silicon microchannel array substrate 1; after the vacuum hot melt filling device cools down to solidify the metal, the metal mold precursor is obtained. Step 3: Etch the silicon in the metal mold precursor to obtain metal mold 9; Step 4: Place the high borosilicate glass material and metal mold 9 into crucible 4, place crucible 4 into vacuum hot-melt filling device, and fill the high borosilicate glass material into metal mold 9 using vacuum hot-melt filling device; cool down to obtain glass-metal composite; etch away all metal material in glass-metal composite to obtain microchannel plate substrate; Step 5: Hydroxylate the microchannel plate substrate; Step 6: Prepare a darad on the microchannel plate substrate using atomic layer deposition and then anneal it to obtain the microchannel plate.

[0022] The following is a detailed description of the microchannel plate fabrication method based on the mold casting method.

[0023] The microchannel plate fabrication method based on the mold casting method includes: Step 1: Obtain silicon microchannel array substrate 1 and preprocess silicon microchannel array substrate 1; Understandably, the silicon microchannel array substrate 1 is a silicon substrate with multiple blind vias 2 on one surface, which is typically planar. Clearly, the blind vias 2 are not through-holes; therefore, the silicon microchannel array substrate 1 is referred to here as a non-permeable silicon microchannel array substrate 1. See also... Figures 2 to 4 , Figure 2 , Figure 3 and Figure 4 This is a structural diagram of the silicon microchannel array substrate 1. Figure 2 The front of the diagram Figure 3 The back of the diagram Figure 4 A schematic cross-section.

[0024] The pretreatment is to increase the diameter of the blind via 2, that is, to increase the opening area ratio of the silicon microchannel array substrate 1.

[0025] The silicon photoelectrochemical etching method was performed using the method described in Chinese Patent No. ZL201210590676.1, entitled "Processing Method of Silicon Microchannel Plate Substrate with Reinforcing Rings". KOH (potassium hydroxide) or TMAH (tetramethylammonium hydroxide) solution was used to etch the silicon microchannel array substrate 1. This process can increase the opening area ratio of the silicon microchannel array substrate 1, thereby increasing the opening area ratio of the MCP; simultaneously, it can improve the smoothness of the inner wall of the blind vias 2 of the silicon microchannel array substrate 1, ensuring the smoothness of the inner wall of the MCP channels.

[0026] Step 2, preparing the metal mold 9: Place the metal mold material 8 in the crucible 4, place the silicon microchannel array substrate 1 on the metal mold material 8, and make the holes of the silicon microchannel array substrate 1 face downwards; place the crucible 4 in a vacuum hot melt filling device, heat the vacuum hot melt filling device to a temperature higher than the melting point of the metal mold material 8, maintain this temperature (not limited to a fixed temperature value, but can be a certain temperature range) while restoring the gas pressure in the vacuum hot melt filling device from vacuum to atmospheric pressure, so as to realize the liquefaction of the metal mold material 8 and fill it into the silicon microchannel array substrate 1; after the vacuum hot melt filling device cools down and the metal solidifies, the metal mold precursor is obtained, and the metal mold precursor is taken out from the vacuum hot melt filling device; the silicon in the metal mold precursor is etched by KOH solution to obtain the metal mold 9.

[0027] Step 2 specifically includes: Step 2.1: Place the metal mold material 8 in the crucible 4, and place the silicon microchannel array substrate 1 on the metal mold material 8. (See below) Figure 5 In this configuration, the metal mold material 8 and the silicon microchannel array substrate 1 are both located in the crucible 4, with the silicon microchannel array substrate 1 resting on the metal mold material 8 and the opening end of the blind hole 2 of the silicon microchannel array substrate 1 facing the metal mold material 8. This method can solve the problem that the silicon microchannel array substrate 1 floats in the molten metal due to density, causing the molten metal mold to not fully fill the silicon microchannel array substrate 1.

[0028] Step 2.2: Place the crucible 4 into the vacuum hot-melt filling device, as shown in the figure. Figure 6 As shown, Figure 5The vacuum tube furnace 3, high-purity nitrogen cylinder 5, valve 6, and vacuum pump 7 of the vacuum hot melt filling device are shown.

[0029] Step 2.3: Control the vacuum degree of the vacuum hot-melt filling device below 10 Pa, and heat the vacuum hot-melt filling device to a temperature higher than the melting point of the metal mold material 8, specifically 50-100°C higher than the metal melting point, to ensure the fluidity of the liquid metal. Figure 7 As shown; maintaining this temperature, gas is introduced into the vacuum hot melt filling device, so that the gas pressure inside the vacuum hot melt filling device is restored to atmospheric pressure, so that the liquid metal mold material 8 is filled into the channel of the silicon microchannel array substrate 1.

[0030] Step 2.4: The vacuum hot-melt filling device is cooled to room temperature at a rate of 5-10℃ / min to obtain the metal mold precursor (also known as the metal mold material-silicon microchannel array substrate composite). The metal mold material-silicon microchannel array substrate composite is then removed from the vacuum hot-melt filling device. It is understood that the cooling process enables metal solidification.

[0031] Step 2.5: A KOH solution with a concentration of 28-32 wt% is heated in a water bath at 75-85°C. Preferably, the KOH solution concentration is 30 wt% and the heating temperature is 80°C. The metal mold material-silicon microchannel array substrate composite is immersed in the KOH solution. The etching time depends on the silicon thickness. After etching, a metal mold 9 corresponding to the silicon microchannel array substrate 1 is obtained. The metal mold 9 is rinsed with deionized water and dried. A schematic diagram of the metal mold 9 can be found in [reference needed]. Figure 8 .

[0032] Step 3, fabrication of the microchannel plate substrate: Place the borosilicate glass material and metal mold 9 into crucible 4, place crucible 4 into a vacuum hot-melt filling device, heat the vacuum hot-melt filling device to a temperature higher than the softening point of the borosilicate glass material, maintain this temperature while restoring the air pressure inside the vacuum hot-melt filling device from vacuum to atmospheric pressure, thereby filling the metal mold 9 with the borosilicate glass material; cool down to obtain a glass-metal composite, remove the glass-metal composite from the vacuum hot-melt filling device; etch away all the metal material in the glass-metal composite to obtain the microchannel plate substrate.

[0033] Specifically, borosilicate glass material is placed on a metal mold 9 and then placed together in a crucible 4. The crucible 4 is then placed in a vacuum hot-melt filling device. The vacuum degree of the vacuum hot-melt filling device is controlled below 10 Pa. The device is heated to at least 200°C above the softening point of the borosilicate glass material, typically 200 to 260°C above the softening point, to ensure the fluidity of the borosilicate glass material. Gas is introduced into the vacuum hot-melt filling device, restoring the internal pressure to atmospheric pressure, allowing the borosilicate glass material to fill the metal mold 9. The metal mold, along with the glass, is slowly and uniformly cooled to the glass's annealing temperature range. The focus of this stage is to eliminate thermal stress. Then, the temperature is lowered at a rate of 5-10°C / min, following the glass's annealing regime, to obtain a glass-metal composite. The glass-metal composite is removed from the crucible 4 and ground until metal pillars (metal pillar array) are exposed on both sides of the glass-metal composite. Then, both sides (excluding the sides) of the glass-metal composite are polished. The polished glass-metal composite was immersed in a metal etching solution to etch away the metal mold 9, thus obtaining the microchannel plate substrate.

[0034] Step 4: Hydroxylation treatment of the microchannel plate substrate: The microchannel plate substrate is ultrasonically cleaned with deionized water, then placed in a piranha solution and heated in a 75-85℃ water bath for 15 to 25 minutes, preferably 80℃ for 20 minutes. The microchannel plate substrate is then removed and cleaned again with deionized water in an ultrasonic cleaner, and dried with nitrogen gas to obtain the hydroxylated microchannel plate substrate. The piranha solution is a mixture of 70 ml concentrated sulfuric acid (98 wt%) and 30 ml hydrogen peroxide solution (30 wt%).

[0035] Step 5: Prepare a dano electrode thin film on the microchannel plate substrate obtained in Step 4 using the ALD (atomic layer deposition) process, including preparing a conductive layer and an emitter layer for the dano electrode.

[0036] The conductive layer comprises a tungsten thin film and an aluminum oxide thin film, and the emitting layer comprises an aluminum oxide thin film. For distinction, the emitting layer comprises a first aluminum oxide thin film; the conductive layer composite film comprises a tungsten thin film and a second aluminum oxide thin film. The aluminum oxide thin film is prepared by atomic layer deposition, and the tungsten thin film is prepared by atomic layer deposition.

[0037] The steps for preparing the aluminum oxide thin film by atomic layer deposition include: introducing a first precursor, trimethylaluminum, which undergoes a chemical adsorption reaction with hydroxyl groups; purging with an inert gas; introducing a second precursor, water vapor, to generate aluminum oxide; and purging with an inert gas.

[0038] The steps for preparing the tungsten thin film by atomic layer deposition include: introducing a third precursor, tungsten hexafluoride, where fluoride ions are chemically adsorbed onto the active sites; purging with an inert gas; introducing a fourth precursor, silane, to reduce tungsten ions to tungsten atoms; and purging with an inert gas.

[0039] In one specific embodiment: The process of preparing aluminum oxide thin films using ALD technology is based on surface self-limiting reactions, and each deposition cycle includes four main steps: Step 5.11: The first precursor is trimethylaluminum. The first precursor trimethylaluminum vapor is pulsed into the reaction chamber and undergoes a chemical adsorption reaction with the hydroxyl groups (-OH) on the surface of the microchannel plate substrate to be prepared / further prepared (e.g., the surface of undeposited or deposited alumina film) to generate Al-O bonds and release methane (CH4). Step 5.12: Introduce an inert gas (such as nitrogen or argon) to purge unreacted trimethylaluminum and byproduct methane from the reaction chamber; Step 5.13: The second precursor is H2O. The water vapor of the second precursor is pulsed into the reaction chamber and continues to react chemically with the surface that has completed the first step reaction to generate aluminum oxide and release methane again. Step 5.14: Inert gas is introduced again to carry away excess water vapor and product methane from the reaction chamber.

[0040] Tungsten thin films were prepared using ALD technology with silane (Si2H6) and tungsten hexafluoride (WF6) as precursors. The specific process was carried out in four cyclic steps: Step 5.21: The third precursor is tungsten hexafluoride. The third precursor tungsten hexafluoride (WF6) pulse adsorption: WF6 vapor is introduced into the reaction chamber, and its fluoride ions will chemically adsorb with the active sites (such as hydroxyl and hydrogen groups) on the surface of the microchannel plate substrate to be prepared / further prepared, forming a layer of surface species containing tungsten-fluorine bonds (WF). The unadsorbed WF6 remains in the gas phase. Step 5.22, Inert gas purging: Introduce inert gases such as nitrogen (N2) or argon (Ar) to completely remove the unadsorbed WF6 gas in the reaction chamber, so as to avoid subsequent direct gas-phase reaction with silane (to prevent film quality deterioration). Step 5.23: The fourth precursor is silane (Si₂H₆). The fourth precursor, silane, undergoes pulsed reduction: Si₂H₆ vapor enters the reaction chamber, where its hydrogen atoms act as reducing agents, reacting with WF-bonded species adsorbed on the surface, thus reducing W... 6 ⁺ is reduced to metallic W (forming W-W bonds), while generating byproducts such as SiF4 and HF. The newly generated W atoms are deposited on the substrate surface. Step 5.24, Inert gas purging: Inert gas is introduced again to remove unreacted Si2H6 and byproducts such as SiF4 and HF generated in the reaction, ensuring that the reaction chamber returns to its initial state and prepares for the next deposition cycle.

[0041] Repeating steps 5.21-5.24 above, tungsten atoms will grow layer by layer through the self-limiting mechanism of "adsorption-reduction", eventually forming a tungsten film with uniform thickness and high purity.

[0042] By repeating the ALD cycle, the thickness of the film can be gradually increased until the desired thickness is achieved.

[0043] Understandably, in one embodiment, the composite conductive layer is prepared by a large cycle consisting of two sub-cycles. By controlling the number of large cycles, composite films of different thicknesses can be prepared, and by controlling the ratio of sub-cycles, composite films with different resistivities can be prepared. The emitter layer is prepared by repeating one cycle. For example, the conductive layer is a stacked structure consisting of 3 layers of tungsten film and 20 layers of Al2O3 film repeated 50 times. The emitter layer is made of Al2O3, requiring only two precursors: trimethylaluminum and H2O.

[0044] Step 6, Annealing: Place the microchannel plate substrate with dano electrodes in a tube furnace, using high-purity nitrogen or argon as a protective atmosphere to maintain the chemical stability and structural integrity of the film. Heat the microchannel plate with dano electrodes in the tube furnace to 500-700℃ at a rate of 5-10℃ / min, and anneal at this temperature for 2-10 h. After annealing, the material is allowed to cool naturally to obtain a microchannel plate.

[0045] The following is a specific application example.

[0046] Pretreatment of silicon microchannel array substrate 1: A non-permeable silicon microchannel array substrate 1 with a thickness of 500 μm and a period of 6 μm was used. Before shaping, the silicon microchannel array was first soaked in hydrofluoric acid and isopropanol for 5 min to remove the native oxide layer. Further, the silicon microchannel array was shaped using a 1 wt% TMAH solution (tetramethylammonium hydroxide solution) at a solution temperature of 40 °C to increase the opening area ratio of the channels, making the opening area ratio greater than 70%.

[0047] Preparation of metal mold 9: (1) Place the opaque silicon microchannel array substrate 1 and pure copper in a crucible 4, and place the crucible 4 in a vacuum hot melt filling device, with the pure copper at the bottom and the silicon microchannel array at the top, with the front of the silicon microchannel array facing down.

[0048] (2) The vacuum degree of the vacuum hot melt filling device is controlled below 10 Pa, and this step (3) is carried out with this vacuum degree.

[0049] (3) Heat the vacuum hot melt filling device to 1150°C.

[0050] (4) Inflate the vacuum hot melt filling device with gas, and restore the gas pressure inside the vacuum hot melt filling device to atmospheric pressure, so that pure copper is filled into the channels of the microchannel array substrate.

[0051] (5) The vacuum hot melt filling device is cooled to room temperature at a rate of 5℃ / min to obtain the metal mold precursor, namely the pure copper-silicon microchannel array substrate composite. The pure copper-silicon microchannel array substrate composite is then removed from the vacuum hot melt filling device.

[0052] (6) Heat a 30wt% KOH solution in an 80℃ water bath and immerse the pure copper-silicon microchannel array substrate composite in the KOH solution until all silicon is etched away. After etching, a pure copper mold (i.e., metal mold 9) corresponding to the silicon microchannel array substrate 1 is obtained. Rinse the pure copper mold with deionized water and dry it.

[0053] Microchannel plate substrate fabrication: (1) Place the high borosilicate glass on the pure copper mold and put it into the crucible 4 together. Then put the crucible 4 into the vacuum hot melt filling device.

[0054] (2) The vacuum level of the device is controlled below 10 Pa.

[0055] (3) Heat the vacuum hot melt filling device to 1020°C.

[0056] (4) Gas is introduced into the vacuum hot melt medium device, and the gas pressure inside the device is restored to atmospheric pressure, so that the high borosilicate glass is filled into the pure copper mold.

[0057] (5) Cool the pure copper mold and glass together to 560°C at a rate of 3°C / min and keep it at that temperature for 2 hours. Then cool it to below 520°C at a rate of 5°C / min and finally cool it to room temperature at a rate of 20°C / min.

[0058] (6) Remove the high borosilicate glass-pure copper composite from the crucible 4 and grind its upper and lower surfaces until the pure copper column array is exposed on both sides of the high borosilicate glass-pure copper composite. Then polish both sides.

[0059] (7) The polished borosilicate glass-pure copper composite was immersed in a 70% nitric acid solution and placed in a fume hood at room temperature to etch away the pure copper mold, thus obtaining the microchannel plate substrate.

[0060] Hydroxylation treatment: The microchannel plate substrate was ultrasonically cleaned with deionized water, then placed in a piranha solution (70 ml concentrated sulfuric acid (98 wt%) and 30 ml hydrogen peroxide solution (30 wt%)), heated in a water bath for about 20 minutes, then placed in an ultrasonic cleaner for 6 minutes, and finally ultrasonically cleaned three times with deionized water and dried with nitrogen.

[0061] Preparation of darads: Using the ALD process, a W / Al2O3 composite film was deposited as the conductive layer of the MCP, with Si2H6 (disilane), WF6 (tungsten hexafluoride), TMA (trimethylaluminum), and H2O as precursors. The ratio of W to Al2O3 was 1:25, and the thickness was 220 nm. The precursors were introduced in the following order: Si2H6, WF6, H2O, TMA. The deposition temperature was 250 °C and the pressure was 40 Pa. Using H2O and TMA as precursors, an Al2O3 film was deposited as the emitter layer of the MCP, with a thickness of 5 nm. The introduction order was: H2O, TMA. The deposition temperature was 200 °C and the pressure was 40 Pa.

[0062] Annealing treatment: The annealing process uses high-purity nitrogen as a protective atmosphere to maintain the chemical stability and structural integrity of the film. The microchannel plate with the prepared darad electrode is heated to 600°C in a tube furnace at a rate of 5°C / min and annealed at a constant temperature for 2 hours. After annealing, it is naturally cooled.

[0063] This disclosure provides a microchannel plate, which is fabricated using the microchannel plate fabrication method based on the mold casting method described in any of the above embodiments.

[0064] This disclosure discloses a microchannel plate fabrication method and a microchannel plate based on the mold casting method. The method involves placing a silicon microchannel array substrate 1 on a metal mold material 8, with the holes of the silicon microchannel array substrate 1 facing downwards. Using a vacuum hot-melt filling device, the metal mold material 8 is fully filled into the silicon microchannel array substrate 1. A metal mold 9 is obtained by etching silicon. High borosilicate glass material and the metal mold 9 are placed in the vacuum hot-melt filling device, allowing the high borosilicate glass material to fill the metal mold 9. The metal material is then etched away to obtain the microchannel plate substrate. The microchannel plate substrate is then subjected to hydroxylation treatment. Finally, operations such as the preparation of a dynamo are performed to obtain the microchannel plate. This design enables the fabrication of microchannel plates with high softening points and high purity, with a high yield. The method disclosed herein uses high borosilicate glass material instead of lead silicate glass using traditional methods. Compared to lead silicate glass, the high borosilicate glass material used in this disclosure has higher purity and higher melting point. The high purity results in lower noise, and the high melting point can increase the baking and exhaust temperature of the microchannel plate, allowing for sufficient exhaust within the channel, thereby improving the lifespan of the image tube.

[0065] 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.

[0066] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for fabricating microchannel plates based on mold casting, characterized in that, Includes the following steps: Step 1: Place the metal mold material in a crucible, place the silicon microchannel array substrate on the metal mold material, and ensure that the holes of the silicon microchannel array substrate face downwards; Step 2: Place the crucible into a vacuum hot melt filling device, and use the vacuum hot melt filling device to liquefy the metal mold material and fill it into the silicon microchannel array substrate; After the vacuum hot melt filling device cools down and solidifies the metal, the metal mold precursor is obtained; Step 3: Etch the silicon in the metal mold precursor to obtain the metal mold; Step 4: Place the high borosilicate glass material and the metal mold into the crucible, and then place the crucible into the vacuum hot-melt filling device. The high borosilicate glass material is then filled into the metal mold using the vacuum hot-melt filling device. Cooling and cooling are used to obtain a glass-metal composite; all the metal materials in the glass-metal composite are etched away to obtain a microchannel plate substrate; Step 5: Hydroxylate the microchannel plate substrate; Step 6: Prepare a darad on the microchannel plate substrate using atomic layer deposition, and then perform annealing treatment to obtain the microchannel plate.

2. The method for fabricating a microchannel plate based on the mold casting method according to claim 1, characterized in that, Before placing the silicon microchannel array substrate on the metal mold material, the method further includes a step of enlarging the diameter of the blind vias.

3. The method for fabricating a microchannel plate based on the mold casting method according to claim 1, characterized in that, Step two specifically involves: placing the crucible into a vacuum hot melt filling device, heating the vacuum hot melt filling device to a temperature higher than the melting point of the metal mold material, maintaining this temperature while restoring the gas pressure inside the vacuum hot melt filling device from vacuum to atmospheric pressure, so as to liquefy the metal mold material and fill it into the silicon microchannel array substrate; after the vacuum hot melt filling device cools down to achieve metal solidification, a metal mold precursor is obtained.

4. The method for fabricating a microchannel plate based on the mold casting method according to claim 3, characterized in that, The vacuum degree in step two is less than 10 Pa; the heating of the vacuum hot melt filling device to a temperature higher than the metal melting point of the metal mold material is specifically: heating the vacuum hot melt filling device to a temperature 50-100°C higher than the metal melting point of the metal mold material.

5. The method for fabricating a microchannel plate based on the mold casting method according to claim 1, characterized in that, Step three specifically involves heating a 28-32 wt% KOH solution in a 75-85°C water bath, immersing the metal mold precursor in the KOH solution to etch silicon, obtaining a metal mold corresponding to the silicon microchannel array substrate after etching, rinsing the metal mold with deionized water and drying it.

6. The method for fabricating a microchannel plate based on the mold casting method according to claim 1, characterized in that, The process of filling high borosilicate glass material into a metal mold using a vacuum hot-melt filling device involves heating the vacuum hot-melt filling device to a temperature higher than the softening point of the high borosilicate glass material, maintaining this temperature while restoring the air pressure inside the vacuum hot-melt filling device from vacuum to atmospheric pressure, thereby filling the high borosilicate glass material into the metal mold.

7. The method for fabricating a microchannel plate based on the mold casting method according to claim 6, characterized in that, The vacuum degree in step four is less than 10 Pa; heating the vacuum hot-melt filling device to a temperature higher than the softening point of the high borosilicate glass material specifically means heating the vacuum hot-melt filling device to a temperature at least 200°C higher than the softening point of the high borosilicate glass material.

8. The method for fabricating a microchannel plate based on the mold casting method according to claim 1, characterized in that, Step five specifically involves: ultrasonically cleaning the microchannel plate substrate with deionized water, immersing it in a piranha solution, heating it in a 75-85℃ water bath for 15-25 minutes, removing the microchannel plate substrate, rinsing it with deionized water in an ultrasonic cleaner, and drying it with nitrogen.

9. The method for fabricating a microchannel plate based on the mold casting method according to claim 1, characterized in that, The method of preparing a dano electrode on a microchannel plate substrate using atomic layer deposition includes preparing a conductive layer and preparing an emission layer. The conductive layer includes a tungsten thin film and an aluminum oxide thin film, and the emission layer includes an aluminum oxide thin film. The steps for preparing the aluminum oxide thin film by atomic layer deposition include: introducing a first precursor, trimethylaluminum, which undergoes a chemical adsorption reaction with hydroxyl groups; purging with an inert gas; introducing a second precursor, water vapor, to generate aluminum oxide; and purging with an inert gas. The steps for preparing the tungsten thin film by atomic layer deposition include: introducing a third precursor, tungsten hexafluoride, where fluoride ions are chemically adsorbed onto the active sites; purging with an inert gas; introducing a fourth precursor, silane, to reduce tungsten ions to tungsten atoms; and purging with an inert gas. The annealing process includes: placing the microchannel plate substrate with danodic electrodes in a tube furnace, using nitrogen or argon as a protective atmosphere, heating the substrate to 500-700°C at a rate of 5-10°C / min, and annealing at a constant temperature for 2-10 hours.

10. A microchannel plate, characterized in that, The microchannel plate is fabricated using the microchannel plate fabrication method based on the mold casting method as described in any one of claims 1 to 9.

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