Method for improving bulk resistance consistency before and after high-temperature baking of micro-channel plate

Abstract

The invention relates to the technical field of micro-channel plates, and discloses a method for improving bulk resistance consistency before and after high-temperature baking of a micro-channel plate, which can be applied to vacuum photoelectric detectors such as an image intensifier and a micro-channel plate type photomultiplier. In the method, after a hydrogen reduction process of a micro-channel plate, an atomic layer deposition process is added, and the atomic layer deposition process comprises the following steps: putting the micro-channel plate into vacuum cavity equipment, and depositing an aluminum oxide film at a certain temperature and pressure intensity; and then preparing an electrode film layer, measuring the bulk resistance of the electrode film layer, and baking the electrode film layer. According to the method, the resistance fluctuation range of the prepared microchannel plate body is obviously reduced, and the product consistency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of microchannel plate technology, and specifically to a method for improving the consistency of body resistance of a microchannel plate before and after high-temperature baking by preparing a nano-functional film layer using an atomic layer deposition process. The method can be applied to vacuum photoelectric detection technologies such as image intensifiers and microchannel plate type photomultiplier tubes. Background Art

[0002] Microchannel Plate (MCP) is a thin hollow glass fiber panel with a honeycomb structure composed of many parallel channels with secondary electron multiplication capability. It can be used to detect various particles such as electrons, neutrons, ions, high-energy particles, X-rays, and high-energy electromagnetic waves.

[0003] The conventional preparation process of microchannel plates relies on glass multi-fiber drawing technology. On the basis of preparing lead silicate skin glass tubes and matching core rods, they are drawn together at high temperature into single fiber filaments, and then go through a series of processes such as rod arrangement, multi-filament drawing, screen arrangement, melting and pressing, slicing, rolling, fine grinding, chamfering, polishing, chemical corrosion, etc. to produce multi-channel array microporous sheets. Then, after hydrogen reduction (forming a secondary electron emission layer on the surface of the microchannel) and plating of the metal electrode film layer, the microchannel plate product is obtained, and after passing the inspection, it is put into storage for standby.

[0004] During the assembly process of the microchannel plate type image intensifier, the microchannel plate used in the third-generation low-light image intensifier needs to be evaporated with a layer of anti-ion feedback film on the input surface of the microchannel plate before installation. Its existence, on the one hand, blocks the ion feedback noise caused by the ion feedback from the end of the microchannel plate, and on the other hand, it also blocks some low-energy photoelectrons from the photocathode, thereby reducing the signal-to-noise ratio. Due to this special requirement, the third-generation low-light image intensifier has higher requirements on the performance of the microchannel plate used in conjunction with it, including the degassing effect and high temperature resistance during the tube manufacturing process. The degassing of the microchannel plate is carried out by high-temperature baking. This process easily leads to changes in the resistance of the microchannel plate body, affecting the performance of the image intensifier preparation and the qualified rate of the entire tube. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention aims to provide a method for obtaining body resistance consistency before and after high-temperature baking by using high-temperature resistant and process-controllable atomic layer deposition technology.

[0006] According to the first aspect of the present invention, a method for preparing a nano-functional film layer by an atomic layer deposition process to improve the consistency of the body resistance of a microchannel plate before and after high-temperature baking is proposed, the method comprising:

[0007] After the microchannel plate is subjected to a hydrogen reduction process and before coating, an atomic layer deposition process step is added, that is, the microchannel plate after hydrogen reduction treatment is placed in an atomic layer deposition device, and at a certain temperature and pressure, a nano-aluminum oxide film is first deposited, and then the electrode film layer is prepared and its body resistance is tested, and finally a high-temperature baking degassing treatment is performed, and then its body resistance is tested.

[0008] As an optional implementation, the deposition of the nano-aluminum oxide film uses trimethylaluminum and H2O as reaction precursors and N2 as carrier gas; the number of deposition cycles is 2 to 50.

[0009] As an optional implementation, in the deposition process, the precursor reaction time is 10 to 300 seconds.

[0010] As an optional implementation, the pressure range of the reaction chamber in the atomic layer deposition equipment is set to 0-500Pa.

[0011] As an optional implementation, in the deposition process, the temperature range is set at 50°C to 300°C.

[0012] As an optional implementation, in the deposition process, the flow rates of the precursor and the carrier gas are between 10 and 100 sccm.

[0013] As an optional embodiment, the number of deposition cycles used is 10 to 50.

[0014] As an optional embodiment, the number of deposition cycles used is 45-50.

[0015] According to the technical scheme of the present invention, the method proposed by the present invention adopts the atomic layer deposition process to prepare a nano-functional film layer to improve the consistency of the volume resistance of the microchannel plate before and after high-temperature baking, changes the process sequence of directly preparing the metal electrode film layer after hydrogen reduction in the traditional process, and then performing high-temperature baking for degassing, but adds the steps of the atomic layer deposition process after the hydrogen reduction process of the microchannel plate, including: placing the microchannel plate after hydrogen reduction treatment into a vacuum chamber equipment, and depositing a nano-aluminum oxide film at a certain temperature and pressure; then preparing the electrode film layer, measuring its volume resistance, and then baking.

[0016] Therefore, in order to solve the problem of body resistance fluctuation caused by direct high-temperature baking in the existing process, the present invention first deposits a layer of aluminum oxide inside the channel to reduce the migration of elements such as Pb and Bi on the inner wall of the channel and the cluster morphology as the temperature increases, thereby affecting the change of body resistance. Therefore, the body resistance fluctuation range of the microchannel plate after tube making obtained by the method of the present invention is significantly reduced, and the product consistency is greatly improved. DETAILED DESCRIPTION

[0017] The purpose of the present invention is to propose a method for preparing a nano-functional film layer using an atomic layer deposition process to improve the consistency of the bulk resistance of a microchannel plate before and after high-temperature baking, changing the process sequence of directly preparing a metal electrode film layer after hydrogen reduction in the traditional process, and then performing high-temperature baking and degassing, but adding the steps of the atomic layer deposition process after the hydrogen reduction process of the microchannel plate, including: placing the microchannel plate after hydrogen reduction treatment into a vacuum chamber device, and depositing a nano-aluminum oxide film at a certain temperature and pressure; then preparing the electrode film layer, measuring its bulk resistance, and then performing high-temperature baking. Therefore, the present invention deposits a layer of aluminum oxide inside the channel first, reduces the migration of elements such as Pb and Bi on the inner wall of the channel and the cluster morphology as the temperature increases, thereby affecting the change of bulk resistance. Therefore, the fluctuation range of the bulk resistance of the microchannel plate obtained by the method of the present invention after tube making is significantly reduced, and the product consistency is greatly improved.

[0018] Method for improving the consistency of bulk resistance of microchannel plate before and after high temperature baking

[0019] In an embodiment of the present invention, after the microchannel plate is subjected to a hydrogen reduction process and before the coating is performed, an atomic layer deposition process step is added, that is, the microchannel plate after the hydrogen reduction process is placed in an atomic layer deposition device, and at a certain temperature and pressure, a nano-aluminum oxide film is first deposited, and then an electrode film layer is prepared and its body resistance is tested, and finally a high-temperature baking degassing process is performed, and then its body resistance is tested.

[0020] As an example the process steps include:

[0021] The first step is to place the MCP (i.e., the arrayed microporous sheet prepared by chemical etching, semiconductor micro-nano processing and other previous processes) on a deposition fixture after the hydrogen reduction treatment is completed and before the film is plated;

[0022] The second step is to place the deposition fixture in the atomic layer deposition equipment, set a certain reaction temperature and reaction pressure, and deposit the nano-aluminum oxide film on the MCP after hydrogen reduction treatment;

[0023] The third step is to prepare the metal electrode film layer of the deposited MCP and test its body resistance;

[0024] Step 4: After the first measurement of the body resistance, the MCP is baked at high temperature and then its body resistance is measured again.

[0025] As an optional implementation, the deposition of the nano-aluminum oxide film uses trimethylaluminum and H2O as reaction precursors and N2 as carrier gas; the number of deposition cycles is 2 to 50.

[0026] As an optional implementation, in the deposition process, the precursor reaction time is 10 to 300 seconds.

[0027] As an optional implementation, the pressure range of the reaction chamber in the atomic layer deposition equipment is set to 0-500Pa.

[0028] As an optional implementation, in the deposition process, the temperature range is set at 50°C to 300°C.

[0029] As an optional implementation, in the deposition process, the flow rates of the precursor and the carrier gas are between 10 and 100 sccm.

[0030] As an optional embodiment, the number of deposition cycles used is 10 to 50.

[0031] As an optional embodiment, the number of deposition cycles used is 45-50.

[0032] As a preferred embodiment, the specific process used in the deposition process is as follows:

[0033] The flow rates of precursor and carrier gas are 60 sccm; the reaction time of precursor is 140 s; the pressure of the reaction chamber is 300 Pa, and the temperature of the reaction chamber is 130°C.

[0034] As an optional implementation, high-temperature baking for degassing is performed at a temperature greater than 300° C., and the high-temperature baking time is not less than 4 hours.

[0035] The present invention is further described below by taking a microchannel plate with a channel aperture of 6 μm, a channel spacing of 7.2 μm, a plate thickness of 0.30 mm, and an aspect ratio of 48 as an example.

[0036] Example 1

[0037] The flow rate of precursor and carrier gas is 60sccm, the pressure of reaction chamber is 300Pa, the reaction temperature is 130℃, the precursor reaction time is 140s, the number of cycles is 10, the nano-aluminum oxide film is deposited, and then the film layer is prepared and its body resistance is tested, and then it is baked at 380℃ for 7 hours, and finally the body resistance is measured.

[0038] Example 2

[0039] The flow rate of precursor and carrier gas is 60sccm, the pressure of reaction chamber is 300Pa, the reaction temperature is 130℃, the precursor reaction time is 140s, the number of cycles is 15, nano-aluminum oxide film is deposited, then the film layer is prepared and its body resistance is tested, and then it is baked at 380℃ for 7 hours, and finally the body resistance is measured.

[0040] Example 3

[0041] The flow rate of precursor and carrier gas is 60sccm, the pressure of reaction chamber is 300Pa, the reaction temperature is 130℃, the precursor reaction time is 140s, the number of cycles is 20, the nano-aluminum oxide film is deposited, and then the film layer is prepared and its body resistance is tested, and then it is baked at 380℃ for 7 hours, and finally the body resistance is measured.

[0042] Example 4

[0043] The flow rate of precursor and carrier gas is 60sccm, the pressure of reaction chamber is 300Pa, the reaction temperature is 130℃, the precursor reaction time is 140s, the number of cycles is 25, nano-aluminum oxide film is deposited, then the film layer is prepared and its body resistance is tested, and then it is baked at 380℃ for 7 hours, and finally the body resistance is measured.

[0044] Example 5

[0045] The flow rate of precursor and carrier gas is 60sccm, the pressure of reaction chamber is 300Pa, the reaction temperature is 130℃, the precursor reaction time is 140s, the number of cycles is 30, the nano-aluminum oxide film is deposited, and then the film layer is prepared and its body resistance is tested, and then it is baked at 380℃ for 7 hours, and finally the body resistance is measured.

[0046] Example 6

[0047] The flow rate of precursor and carrier gas is 60sccm, the pressure of reaction chamber is 300Pa, the reaction temperature is 130℃, the precursor reaction time is 140s, the number of cycles is 35, nano-aluminum oxide film is deposited, then the film layer is prepared and its body resistance is tested, and then it is baked at 380℃ for 7 hours, and finally the body resistance is measured.

[0048] Example 7

[0049] The flow rate of precursor and carrier gas is 60sccm, the pressure of reaction chamber is 300Pa, the reaction temperature is 130℃, the precursor reaction time is 140s, the number of cycles is 40, the nano-aluminum oxide film is deposited, and then the film layer is prepared and its body resistance is tested, and then it is baked at 380℃ for 7 hours, and finally the body resistance is measured.

[0050] Example 8

[0051] The flow rate of precursor and carrier gas is 60sccm, the pressure of reaction chamber is 300Pa, the reaction temperature is 130℃, the precursor reaction time is 140s, the number of cycles is 45, nano-aluminum oxide film is deposited, then the film layer is prepared and its body resistance is tested, and then it is baked at 380℃ for 7 hours, and finally the body resistance is measured.

[0052] Example 9

[0053] The flow rate of precursor and carrier gas is 60sccm, the pressure of reaction chamber is 300Pa, the reaction temperature is 130℃, the precursor reaction time is 140s, the number of cycles is 50, nano-aluminum oxide film is deposited, then the film layer is prepared and its body resistance is tested, and then it is baked at 380℃ for 7 hours, and finally the body resistance is measured.

[0054] It should be understood that in the nano-aluminum oxide film deposition processes of the aforementioned embodiments, the more deposition cycles there are, the thicker the nano-aluminum oxide film will be.

[0055] According to the preparation method of the above embodiment, a microchannel plate was prepared and degassing and volume resistance detection were performed. By controlling the reaction time, temperature and vacuum degree and adjusting the number of cycles, the volume resistance test results of the obtained microchannel plate are compared as shown in the following table, wherein the volume resistance changes with the increase of the number of cycles, first decreases and then remains stable. When the number of cycles is 45, the volume resistance remains stable before and after baking.

[0056]

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for improving the consistency of bulk resistance of a microchannel plate before and after high temperature baking, characterized in that: The method comprises: After the microchannel plate is subjected to a hydrogen reduction process and before coating, an atomic layer deposition process step is added, that is, the microchannel plate after hydrogen reduction treatment is placed in an atomic layer deposition device, and at a certain temperature and pressure, a nano-aluminum oxide film is first deposited, and then the electrode film layer is prepared and its body resistance is tested, and finally a high-temperature baking degassing treatment is performed, and then its body resistance is tested.

2. The method for improving the consistency of bulk resistance of a microchannel plate before and after high temperature baking according to claim 1, characterized in that: The deposition of the nano aluminum oxide film uses trimethyl aluminum and H2O as reaction precursors and N2 as carrier gas; the deposition cycle number is 2 to 50.

3. The method for improving the consistency of bulk resistance of a microchannel plate before and after high temperature baking according to claim 1, characterized in that: In the deposition process, the precursor reaction time is 10 to 300 seconds.

4. The method for improving the consistency of bulk resistance of a microchannel plate before and after high temperature baking according to claim 1, characterized in that: The pressure range of the reaction chamber in the atomic layer deposition equipment is set at 0-500Pa.

5. The method for improving the consistency of bulk resistance of a microchannel plate before and after high temperature baking according to claim 1, characterized in that: In the deposition process, the temperature range is set at 50°C to 300°C.

6. The method for improving the consistency of bulk resistance of a microchannel plate before and after high temperature baking according to claim 1, characterized in that: In the deposition process, the flow rates of the precursor and the carrier gas are between 10 and 100 sccm.

7. The method for improving the consistency of bulk resistance of a microchannel plate before and after high temperature baking according to claim 1, characterized in that: The number of deposition cycles used was between 10 and 50.

8. The method for improving the consistency of bulk resistance of a microchannel plate before and after high temperature baking according to claim 1, characterized in that: The number of deposition cycles used was 45-50.

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