GEM probe with ordered nuclear pore membrane and wave-absorbing material complete preparation process

Abstract

The application relates to the technical field of nuclear pore membrane functional material preparation, in particular to a complete preparation process of an ordered nuclear pore membrane matched with a GEM probe and a wave-absorbing material, which comprises the following steps: preparing an ordered nuclear pore membrane base film with nuclear micropores arranged in an order; the nuclear micropores on the ordered nuclear pore membrane base film have consistent pore intervals and are arranged in a regular array; the ordered nuclear pore membrane base film is divided into a first sub-batch and a second sub-batch, and the first sub-batch and the second sub-batch are subjected to parameter diversion treatment respectively. The ordered nuclear pore membrane base film with nuclear micropores arranged in an order is prepared as a common upstream, the base film is divided into the first sub-batch and the second sub-batch for parameter diversion, the first sub-batch is guided to GEM probe film preparation, the second sub-batch is guided to wave-absorbing material film preparation, and the same base film batch can simultaneously meet different demands of two types of terminal products on nuclear pore membrane parameters.

Description

Technical Field

[0001] This invention relates to the field of nuclear pore membrane functional material preparation technology, specifically to a complete preparation process for ordered nuclear pore membranes paired with GEM probes and microwave absorbing materials. Background Technology

[0002] Nuclear pore membranes, also known as track-etched membranes, are precision microporous membranes formed by chemical etching after a high-energy heavy ion beam penetrates a polymer film. They are characterized by uniform and controllable pore size, regular and straight channels, and smooth membrane surface, and have important applications in filtration and separation, biomedicine, electronic devices, radiation detection, and microwave absorption stealth.

[0003] In the field of radiation detection, a gas electron multiplier (GEM) is a microstructured gas detector. Its core component is an insulating microporous membrane with metal plating on both sides, which achieves electron multiplication by creating a strong electric field within the micropores. Traditional GEM membranes are mostly fabricated by photolithography etching after double-sided copper plating of polyimide films. The arrangement of micropores is determined by the photolithographic mask, and the pore diameter and spacing are limited by the precision of the photolithography process. The development of core-pore membrane technology has provided a new path for the fabrication of GEM probes: by utilizing the vertically interconnected pore characteristics of core-pore membranes, a layer of insulating core-pore membrane can be sandwiched between two conductive core-pore membranes to form a GEM probe structure with electron multiplication function.

[0004] In the field of microwave absorbing materials, the microporous structure of core-pore membranes can achieve absorption of electromagnetic waves in specific frequency bands by controlling the pore size and cone angle. Stacking and alternating core-pore membranes with different pore sizes and cone angles can expand the range of electromagnetic wavelengths that the absorbing material can absorb. However, the multilayer stacking of core-pore membrane microwave absorbing materials requires high precision in pore alignment, and existing processes mostly rely on manual stacking, making it difficult to guarantee consistency.

[0005] Currently, the preparation of ordered nuclear pore membranes, GEM probes, and absorbing materials are typically completed as independent processes. After the nuclear pore membrane manufacturer prepares the ordered nuclear pore membrane base film, downstream manufacturers perform secondary processing according to the requirements of either the GEM probe or the absorbing material. There is a lack of a unified process route that integrates base film preparation with the preparation of both types of products. This separate production model has the following shortcomings: First, the same batch of base film cannot be separated according to product requirements. The pore size and inner cone angle parameters required by GEM probes and absorbing materials differ significantly, and purchasing and processing base films separately leads to fragmented production scheduling and numerous material turnover steps. Second, there is a lack of a unified process control framework for the one-to-one correspondence accuracy of the nuclear micropores in the three-layer membrane of the GEM probe and the accuracy of the staggered pore arrangement in the multi-layer membrane of the absorbing material. The pore position accuracy control methods for the two types of products are independent, making it difficult to share quality inspection and feedback adjustment mechanisms. Third, separate production results in large base film cutting allowances and process changeover losses, restricting overall production efficiency and product consistency.

[0006] To address the aforementioned issues, we propose a complete fabrication process for ordered nuclear pore membranes paired with GEM probes and absorbing materials. Summary of the Invention

[0007] The purpose of this invention is to provide a complete fabrication process for ordered nuclear pore membranes, GEM probes, and absorbing materials to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: The complete fabrication process of ordered nuclear pore membranes with GEM probes and absorbing materials includes the following steps: S1: Prepare an ordered nuclear pore membrane base film with neatly arranged nuclear micropores, wherein the nuclear micropores on the ordered nuclear pore membrane base film have a consistent pore spacing and are arranged in a regular array; S2: Divide the ordered nuclear pore membrane base membrane into a first sub-batch and a second sub-batch, and perform parameter splitting processing on the first sub-batch and the second sub-batch respectively; S3: Prepare a GEM probe membrane for the first sub-batch, including preparing two conductive core pore membranes and one insulating core pore membrane from the first sub-batch, stacking the two conductive core pore membranes on both sides of the insulating core pore membrane respectively, so that the spacing of the nuclear micropores on the three core pore membranes is consistent and corresponds one-to-one, and forming a GEM probe composite membrane through interlayer bonding. S4: Prepare a microwave absorbing material membrane for the second sub-batch, including preparing a nuclear pore membrane with different pore sizes by controlling the chemical etching time, preparing a nuclear pore membrane with different inner cone angles by controlling the sensitization time, stacking and assembling multilayer nuclear pore membranes with different pore sizes and inner cone angles, so that the nuclear micropores of adjacent membranes are staggered and arranged in an alternating manner, and forming a microwave absorbing material stack by interlayer fixation.

[0009] Preferably, in step S1, the specific process for preparing the ordered nuclear pore membrane base film is as follows: S11: Prepare a single-pore nuclear pore membrane by stacking multiple layers of randomly distributed nuclear pore membranes and aligning the single nuclear pores of each layer under a scanning electron microscope to form a through hole. After fixing, a single-pore transmission membrane is prepared. The original membrane is placed behind the single-pore transmission membrane and bombarded with a particle beam from the front. The original membrane is removed and sensitized and chemically etched to obtain a single-pore nuclear pore membrane. S12: Multiple single-pore nuclear pore membranes are stacked to align the nuclear micropores and form a new single-pore transmission membrane. The original membrane is placed behind and bombarded with a particle beam. Then, it is moved laterally at a predetermined distance under a scanning electron microscope and bombarded again. After sensitization and chemical etching, a double-pore nuclear pore membrane with a predetermined pore spacing is obtained. S13: A dual-pore transmission membrane is made from the dual-pore nuclear pore membrane. The original membrane is placed behind the particle beam and then moved longitudinally at a predetermined distance to bombard it again. After sensitization and chemical etching, a four-pore nuclear pore membrane is obtained. S14: Repeat the above transmission membrane iteration steps to gradually increase the area of ​​the nuclear micropore array and obtain an ordered nuclear pore membrane base film with consistent and regularly arranged nuclear micropore spacing.

[0010] Preferably, in step S2, the specific process of parameter splitting is as follows: Based on the different requirements of GEM probes and absorbing materials for the pore size, inner cone angle, and film thickness of the nuclear pore membrane, the ordered nuclear pore membrane base film is cut into a first sub-batch and a second sub-batch. The etching time and sensitization time parameters adapted to the GEM probe are set for the first sub-batch, and multiple sets of etching time and sensitization time parameters adapted to the absorbing material are set for the second sub-batch, so that the same base film batch is respectively guided to the preparation process of two types of products.

[0011] Preferably, in step S3, the specific process for preparing the conductive layer core-pore film and the insulating layer core-pore film is as follows: A conductive material film is selected as the substrate of the conductive layer core pore film, and an insulating material film is selected as the substrate of the insulating layer core pore film. The conductive material film and the insulating material film are subjected to particle bombardment, sensitization and chemical etching respectively according to the ordered core pore film preparation process in step S1 to obtain a conductive layer core pore film and an insulating layer core pore film with consistent core micropore spacing. Alternatively, after depositing conductive layers on both sides of an insulating film, neatly arranged nuclear micropores are punched on the film according to the process in step S1 to obtain a nuclear pore film that is conductive on both sides.

[0012] Preferably, in step S3, the specific process of stacking, aligning, and bonding the three nuclear pore membranes is as follows: Positioning and alignment marks are pre-made on the edges of the conductive layer core pore membrane and the insulating layer core pore membrane. During the stacking, the positioning and alignment marks are used to make the centers of the core micropores of the three layers of core pore membranes coincide one by one in the direction perpendicular to the membrane surface. After confirming the correspondence of the pore positions, interlayer bonding material is applied to the edge area of ​​the three layers of membrane. After curing, the three layers of membrane form an integral GEM probe composite membrane.

[0013] Preferably, the conductive material is at least one of copper, gold, or aluminum, and the insulating material is at least one of polyimide, polycarbonate, or polyester.

[0014] Preferably, in step S4, the specific process for preparing nuclear pore membranes with different pore sizes and inner cone angles is as follows: Different chemical etching times were set for each group of films in the second sub-batch. The longer the etching time, the larger the nuclear micropore diameter, thus obtaining multiple groups of nuclear pore films with gradient pore size distribution. Different sensitization times were set for each group of membranes. The longer the sensitization time, the larger the inner cone angle of the nuclear micropores, thus obtaining multiple groups of nuclear pore membranes with a gradient distribution of inner cone angles. By combining the pore size gradient with the inner cone angle gradient, multilayer nuclear pore membranes with different pore sizes and inner cone angle combinations can be obtained.

[0015] Preferably, in step S4, the specific process of alternating and fixing the multilayer nuclear pore membranes is as follows: Multilayer nuclear pore membranes with different pore sizes and inner cone angles are stacked sequentially in order of increasing or decreasing pore size. During stacking, the nuclear micropore arrays of two adjacent nuclear pore membranes are offset from each other by half a pore spacing within the membrane surface, so that the nuclear micropore positions of adjacent membranes are staggered and arranged in an alternating manner. Interlayer fixing adhesive is applied to the edge region between adjacent membrane layers, and the layers are then pressed and cured to form a monolithic microwave absorbing material stack.

[0016] Preferably, the multilayer nuclear pore membrane has no fewer than three layers, and the offset directions between adjacent membrane layers are the same or alternate.

[0017] Preferably, the method further includes the following steps: S5: Complete process quality inspection, the specific process is as follows: The one-to-one correspondence accuracy of the three-layer nuclear micropores in the GEM probe composite film was detected by scanning electron microscopy, and the cross-offset of the nuclear micropores in adjacent film layers in the microwave absorbing material stack was detected by scanning electron microscopy. When the detection result exceeds the preset accuracy range, feedback is provided to adjust the overlapping alignment parameter in step S3 or the interleaving offset parameter in step S4.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1) This invention uses an ordered nuclear pore membrane base film with neatly arranged nuclear micropores as a common upstream component. The base film is divided into a first sub-batch and a second sub-batch for parameter separation. The first sub-batch is used for GEM probe membrane preparation, and the second sub-batch is used for absorbing material membrane preparation. This allows the same base film batch to simultaneously meet the different parameter requirements of two types of end products. It is understood that GEM probes require consistent and one-to-one spacing between the nuclear micropores in the three-layer membrane, while absorbing materials require multi-layer membranes with different pore diameters and inner cone angles, and staggered pore arrangement. The two types of products have significantly different requirements for subsequent processing parameters of the base film. This parameter separation mechanism eliminates the need for customized base film preparation for a single product. Instead, it allows for the simultaneous production of both types of products on a unified base film platform through downstream parameter differentiation, reducing material turnover and process changeover steps and improving overall production efficiency.

[0019] 2) In the fabrication of the film for GEM probes, this invention involves preparing two conductive core-pore films and one insulating core-pore film in the first batch. By using edge positioning alignment marks, the centers of the core micropores in the three core-pore films are aligned vertically and then bonded together to form the GEM probe composite film. It is understood that the electron multiplication function of the GEM probe relies on the uniform and strong electric field formed within the micropores. The one-to-one correspondence accuracy of the core micropores in the three films directly affects the uniformity of the electric field distribution and the gain stability. By controlling the alignment accuracy of the three films within a unified process framework and sharing the aperture spacing parameters with the base film fabrication stage, the consistency of the micropore correspondence in the GEM probe composite film can be ensured, which is beneficial for improving the gain uniformity and operational stability of the detector. Simultaneously, two implementation paths are provided: stacking three discrete films and drilling holes after double-sided conductive layer deposition on the insulating film, allowing for flexible selection based on material characteristics and process conditions.

[0020] 3) In the fabrication of microwave absorbing materials, this invention prepares core-pore films with different pore sizes by controlling the chemical etching time and core-pore films with different inner cone angles by controlling the sensitization time. These multilayer core-pore films with different pore sizes and inner cone angles are then stacked and fixed with adjacent pore positions staggered by half a pore spacing to form a microwave absorbing material stack. It is understood that the pore size and inner cone angle of the core-pore film determine its resonant absorption characteristics for specific frequency bands of electromagnetic waves. Combinations of films with different pore sizes and inner cone angles can cover a wider range of electromagnetic wave wavelengths. The staggered pore positions of adjacent films avoid electromagnetic wave transmission caused by direct passage through the multilayer film channels, which is beneficial for enhancing multiple reflections and absorption effects. Under a unified process framework, the pore size gradient, cone angle gradient, and staggered offset of the microwave absorbing material can all be set collaboratively with the pore spacing parameters in the base film fabrication stage, which helps ensure the structural consistency and repeatability of the microwave absorption performance of the multilayer absorbing film.

[0021] 4) This invention employs a complete set of process quality inspection steps to uniformly inspect the one-to-one correspondence accuracy of the three-layer core micropores in the GEM probe composite film and the staggered offset of adjacent film layers in the absorbing material stack using scanning electron microscopy. When the inspection results exceed tolerances, feedback is provided to adjust the stacking alignment parameters or staggered offset parameters. It is understood that although the aperture position accuracy of the two types of products differs in form (one-to-one correspondence and mutual staggering), their inspection methods and feedback adjustment logic can be shared within a unified framework. This unified quality control mechanism avoids the redundant investment of establishing separate inspection and feedback systems for the two types of products, which is beneficial for continuously ensuring the aperture position accuracy of both types of products in the complete process, improving product consistency and yield. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall process for the preparation of the ordered nuclear pore membrane, the matching GEM probe, and the microwave absorbing material of the present invention. Figure 2 This is a flowchart of the entire process unit flow of the present invention. Detailed Implementation

[0023] 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, and 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.

[0024] like Figure 1 As shown, this invention provides a complete fabrication process for ordered nuclear pore membranes, GEM probes, and absorbing materials. After the ordered nuclear pore membrane base film is fabricated in the base film fabrication unit, it is divided into a first sub-batch and a second sub-batch by a parameter splitting unit, and then directed to the GEM probe fabrication unit and the absorbing material fabrication unit, respectively. The specific process includes the following steps: S1: In the base film preparation unit, an ordered nuclear pore membrane base film with neatly arranged nuclear micropores is prepared. The nuclear micropores on the ordered nuclear pore membrane base film have a consistent pore spacing and are arranged in a regular array. S2: The ordered nuclear pore membrane base film is divided into a first sub-batch and a second sub-batch by the parameter splitting unit, and different etching and sensitization parameters are set for the first sub-batch and the second sub-batch respectively for splitting processing; S3: In the GEM probe fabrication unit, the first sub-batch is prepared with a GEM probe film, including the preparation of two conductive core pore films and one insulating core pore film from the first sub-batch. The two conductive core pore films are stacked on both sides of the insulating core pore film, so that the spacing of the nuclear micropores on the three core pore films is consistent and corresponds one-to-one. The GEM probe composite film is formed by interlayer bonding. S4: In the microwave absorbing material preparation unit, the second sub-batch is prepared with microwave absorbing material membranes, including preparing nuclear pore membranes with different pore sizes by controlling the chemical etching time, preparing nuclear pore membranes with different inner cone angles by controlling the sensitization time, stacking and assembling multilayer nuclear pore membranes with different pore sizes and inner cone angles, so that the nuclear micropores of adjacent membranes are staggered and arranged in an alternating manner, and then fixed with interlayer fixative to form a microwave absorbing material stack.

[0025] like Figure 1 , Figure 2 As shown, in a preferred embodiment of the present invention, the specific process of preparing an ordered nuclear pore membrane base film in the base film preparation unit in S1 is as follows: S11: Preparation of a single-pore nuclear pore membrane. First, obtain a nuclear pore membrane with a random distribution of nuclear micropores, such as gold foil, which has fewer transmitting particles. Manipulate the sample under a scanning electron microscope, stacking multiple layers of randomly distributed nuclear pore membranes, aligning a single nuclear pore on each layer to form an individual through-hole. After fixing the layers, a single-pore transmission membrane is formed. Place the original membrane to be used as the single-pore nuclear pore membrane behind the single-pore transmission membrane, and bombard the front of the single-pore transmission membrane with a particle beam. The particle beam energy level can be appropriately lowered to increase the success rate of a single bombardment. After bombardment, remove the original membrane behind it, and perform sensitization and chemical etching to obtain a nuclear pore membrane with a single nuclear micropore. Increasing the chemical etching time can increase the pore size of the nuclear micropore, which is beneficial to the success rate of the transmission membrane alignment operation in subsequent steps. If the first bombardment fails to form a single pore, the sample membrane can be stacked again behind the single-pore transmission membrane to increase the thickness of the transmission membrane, and the bombardment process can be repeated until a nuclear pore membrane with a single nuclear micropore is successfully fabricated.

[0026] S12: Fabrication of a dual-pore nuclear membrane with a fixed and neatly arranged nuclear micropore spacing. Multiple single-pore nuclear membranes prepared in the previous steps are stacked, and the nuclear micropores on each membrane are aligned to form through-holes. The number of single-pore nuclear membranes is maximized to increase the transmission success rate, thus creating a new single-pore transmission membrane. The original membrane to be used as the dual-pore nuclear membrane is placed behind the single-pore transmission membrane, and a particle beam is bombarded towards the front of the transmission membrane. Then, under a scanning electron microscope, the original membrane behind it is moved laterally by a predetermined spacing (e.g., ten micrometers), and bombarded again with a particle beam. After bombardment, the sample membrane behind it is removed, and after sensitization and chemical etching, a dual-pore nuclear membrane with a predetermined nuclear micropore spacing is obtained.

[0027] S13: Fabrication of a four-pore nuclear membrane with a fixed spacing and neat arrangement of nuclear micropores. Multiple aforementioned two-pore nuclear membranes are stacked, with the nuclear micropores aligned to form through-holes. The number of stacked membranes should be as large as possible to create a new two-pore transmission membrane. The original membrane to be used as the four-pore nuclear membrane is placed behind the two-pore transmission membrane, and a particle beam is bombarded towards the front of the transmission membrane. Under a scanning electron microscope, the original membrane behind the membrane is moved longitudinally and laterally by the same predetermined distance, and then bombarded again with the particle beam. The sample membrane is removed, sensitized, and chemically etched to obtain a four-pore nuclear membrane with consistent spacing and a regular arrangement of two rows and two columns of nuclear micropores.

[0028] S14: Repeat the above iterative steps for the transmission film, each time using the porous nuclear pore membrane obtained in the previous round to create a new transmission film, gradually expanding the area of ​​the nuclear micropore array through horizontal and vertical bombardment. After multiple iterations, an ordered nuclear pore membrane base film with consistent spacing and a regular array arrangement per unit area can be obtained. This ordered nuclear pore membrane base film serves as a shared upstream material for the subsequent fabrication of GEM probes and absorbing materials, and its pore spacing parameters are used in the subsequent processes of both types of products.

[0029] In another preferred embodiment of the present invention, the specific process of parameter splitting in the parameter splitting unit in S2 is as follows: Based on the different requirements of GEM probes and absorbing materials for the pore size, inner cone angle, and film thickness of the nuclear pore membrane, the ordered nuclear pore membrane substrate prepared in S1 is cut into a first sub-batch and a second sub-batch. The first sub-batch is sent to the GEM probe fabrication unit for the fabrication of the membrane for the GEM probe, which has high requirements for the consistency of the pore size of the nuclear micropores, and the pore spacing of the three layers of the membrane must be strictly consistent. The second sub-batch is sent to the absorbing material fabrication unit for the fabrication of the membrane for the absorbing material, which requires multiple sets of membrane layers with different pore sizes and inner cone angles. Etching and sensitization time parameters adapted to the GEM probe are set for the first sub-batch, so that the membranes in this batch obtain pore sizes and channel shapes suitable for electron multiplication in the GEM probe after subsequent etching. Multiple sets of etching and sensitization time parameters adapted to the absorbing material are set for the second sub-batch, so that each set of membranes in this batch obtains different pore sizes and inner cone angles. By using the above-mentioned parameter diversion, the same batch of ordered nuclear pore membrane base film is directed to the preparation processes of two types of products respectively. The output of the base film preparation unit is shared by the two types of products, reducing the material turnover links of separate material preparation.

[0030] In another preferred embodiment of the present invention, the specific process of preparing the conductive layer core-pore film and the insulating layer core-pore film, as well as the three-layer stacking alignment and bonding in S3 within the GEM probe fabrication unit is as follows: A conductive material thin film is selected as the substrate for the conductive layer core-pore membrane. The conductive material can be a metal thin film such as copper, gold, or aluminum, forming the conductive layer of the GEM probe composite membrane. An insulating material thin film is selected as the substrate for the insulating layer core-pore membrane. The insulating material can be a polymer thin film such as polyimide, polycarbonate, or polyester, forming the insulating layer of the GEM probe composite membrane. The conductive and insulating material thin films are subjected to particle bombardment, sensitization, and chemical etching according to the ordered core-pore membrane substrate preparation process of S1, respectively, to obtain conductive and insulating core-pore membranes with consistent micropore spacing. Since all three types of membranes are prepared using the same transmission membrane iterative process and the same pore spacing parameters, the pore spacing of their micropore arrays is naturally consistent, providing a basis for the one-to-one correspondence of the subsequent three-layer stacking.

[0031] As another approach, conductive layers can be deposited on both sides of an insulating film, and then neatly arranged micropores can be punched into the composite film according to process S1 to directly obtain a double-sided conductive micropore film. This method eliminates the need for the stacking and alignment of three discrete films, but it requires high coating uniformity and drilling precision, and is suitable for cases with small film surface size.

[0032] When using a three-layer discrete film scheme, positioning alignment marks are pre-fabricated on the edges of the conductive and insulating core-pore films. These markings can be made using photolithography or mechanical scribing, and can be cross-shaped or square. During stacking, the first conductive core-pore film is placed flat on a positioning fixture, and the insulating core-pore film is placed on top of it. The positioning alignment marks at the edges are used to ensure that the centers of the core micropores of the two films coincide in the direction perpendicular to the film surface. Then, the second conductive core-pore film is placed on top of the insulating core-pore film, and the positioning alignment marks are used to ensure that the centers of the core micropores of all three core-pore films coincide. After confirming the alignment of the pores, an interlayer bonding material is applied to the edge areas of the three films. The bonding material can be epoxy resin or thermosetting adhesive film. After heating or UV curing, the three films form a monolithic GEM probe composite film. In this GEM probe composite film, two conductive layers serve as the upper and lower electrodes of the GEM probe, respectively, the middle insulating layer serves as the supporting medium, and the nuclear micropores serve as electron multiplication channels. When a voltage is applied between the two conductive layers, a strong electric field can be formed in the micropores to achieve electron multiplication.

[0033] In another preferred embodiment of the present invention, in S4, the specific process of preparing a core-pore membrane with different pore sizes and inner cone angles, and the multilayer staggered stacking and fixing thereof in the microwave absorbing material preparation unit is as follows: Different chemical etching times were set for each group of films in the second sub-batch. During chemical etching, the etchant dissolves the film material along the ion track direction. The longer the etching time, the greater the degree of dissolution and expansion of the nuclear micropores, and the larger the pore size. By setting progressively increasing etching times for each group of films, multiple groups of nuclear-pore films with gradient pore size distributions can be obtained, such as small-pore, medium-pore, and large-pore groups. Simultaneously, different sensitization times were set for each group of films. Sensitization treatment alters the etching selectivity of the material around the ion track through ultraviolet light irradiation or chemical pretreatment. The longer the sensitization time, the wider the sensitized area around the track, and the larger the inner cone angle of the nuclear micropores formed after chemical etching. By setting progressively increasing sensitization times for each group of films, multiple groups of nuclear-pore films with gradient inner cone angle distributions can be obtained. By combining pore size gradients with inner cone angle gradients, such as small pore size with small cone angle, medium pore size with medium cone angle, large pore size with large cone angle, or cross-combining them, multilayer nuclear pore membranes with different pore size and inner cone angle combinations can be obtained.

[0034] Multilayer nuclear porous membranes with different pore sizes and inner cone angles are stacked sequentially in ascending order of pore size, or in descending order of pore size, depending on the design requirements of the absorption frequency band. During stacking, the micropore arrays of adjacent nuclear porous membranes are offset from each other by half a pore spacing within the membrane surface. That is, the center of the micropore of the upper membrane corresponds exactly to the center position of the four adjacent micropores of the lower membrane, thus staggering and interleaving the micropore positions of adjacent membranes. The number of multilayer nuclear porous membranes is no less than three. The offset direction between adjacent membrane layers can be the same (always offset by half a pore spacing in the same direction) or alternate (odd-numbered layers offset in one direction, even-numbered layers offset in a vertical direction), depending on the design requirements of the absorption performance. An interlayer fixing adhesive, such as epoxy resin or acrylic adhesive, is applied to the edge region between adjacent membrane layers. After pressing and curing, the multilayer nuclear porous membranes form a monolithic microwave absorbing material laminate.

[0035] It is understandable that membranes with different pore sizes exhibit different resonant absorption characteristics for electromagnetic waves of different wavelengths. Membranes with smaller pore sizes primarily absorb shorter wavelengths, while those with larger pore sizes primarily absorb longer wavelengths. Differences in the inner cone angle affect the multiple reflection paths and absorption efficiency of electromagnetic waves within the pores. Combining membranes with different pore sizes and inner cone angles allows the absorbing material stack to cover a wider range of electromagnetic wavelengths. Staggering the pore positions of adjacent membrane layers by half a pore spacing avoids straight-through channels in the vertical direction. As incident electromagnetic waves pass through each layer, they encounter different pore edges, resulting in multiple scattering and reflections, which lengthens the propagation path of the electromagnetic waves within the membrane layers and enhances the absorption effect.

[0036] In another preferred embodiment of the present invention, S5 is further included: complete process quality inspection, the specific process of which is as follows: For the GEM probe composite film prepared in S3, scanning electron microscopy (SEM) was used to select observation points in multiple regions on the film surface to detect the one-to-one correspondence accuracy of the three layers of micropores in the vertical direction, i.e., the offset of the centers of the upper and lower layers of micropores. For the microwave absorbing material stack prepared in S4, SEM was also used to detect the staggered offset of the micropores in adjacent film layers to confirm whether the actual offset reached half the designed aperture spacing. When the micropore offset of the GEM probe composite film exceeded the preset accuracy range, the superposition alignment parameters in S3 were adjusted, such as adjusting the positioning accuracy of the positioning fixture or the fabrication accuracy of the positioning alignment marks; when the staggered offset of the microwave absorbing material stack exceeded the preset range, the staggered offset parameters in S4 were adjusted, such as adjusting the offset positioning accuracy of the superposition fixture. Through unified SEM detection methods and feedback adjustment logic, the aperture accuracy of the GEM probe composite film and the microwave absorbing material stack was continuously guaranteed within the same complete process framework.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A complete fabrication process for ordered nuclear pore membranes paired with GEM probes and absorbing materials, characterized in that, Includes the following steps: S1: Prepare an ordered nuclear pore membrane base film with neatly arranged nuclear micropores, wherein the nuclear micropores on the ordered nuclear pore membrane base film have a consistent pore spacing and are arranged in a regular array; S2: Divide the ordered nuclear pore membrane base membrane into a first sub-batch and a second sub-batch, and perform parameter splitting processing on the first sub-batch and the second sub-batch respectively; S3: Prepare a GEM probe membrane for the first sub-batch, including preparing two conductive core pore membranes and one insulating core pore membrane from the first sub-batch, stacking the two conductive core pore membranes on both sides of the insulating core pore membrane respectively, so that the spacing of the nuclear micropores on the three core pore membranes is consistent and corresponds one-to-one, and forming a GEM probe composite membrane through interlayer bonding. S4: Prepare a microwave absorbing material membrane for the second sub-batch, including preparing a nuclear pore membrane with different pore sizes by controlling the chemical etching time, preparing a nuclear pore membrane with different inner cone angles by controlling the sensitization time, stacking and assembling multilayer nuclear pore membranes with different pore sizes and inner cone angles, so that the nuclear micropores of adjacent membranes are staggered and arranged in an alternating manner, and forming a microwave absorbing material stack by interlayer fixation.

2. The complete fabrication process of the ordered nuclear pore membrane with GEM probe and absorbing material according to claim 1, characterized in that, In step S1, the specific process for preparing the ordered nuclear pore membrane base film is as follows: S11: Prepare a single-pore nuclear pore membrane by stacking multiple layers of randomly distributed nuclear pore membranes and aligning the single nuclear pores of each layer under a scanning electron microscope to form a through hole. After fixing, a single-pore transmission membrane is prepared. The original membrane is placed behind the single-pore transmission membrane and bombarded with a particle beam from the front. The original membrane is removed and sensitized and chemically etched to obtain a single-pore nuclear pore membrane. S12: Multiple single-pore nuclear pore membranes are stacked to align the nuclear micropores and form a new single-pore transmission membrane. The original membrane is placed behind and bombarded with a particle beam. Then, it is moved laterally at a predetermined distance under a scanning electron microscope and bombarded again. After sensitization and chemical etching, a double-pore nuclear pore membrane with a predetermined pore spacing is obtained. S13: A dual-pore transmission membrane is made from the dual-pore nuclear pore membrane. The original membrane is placed behind the particle beam and then moved longitudinally at a predetermined distance to bombard it again. After sensitization and chemical etching, a four-pore nuclear pore membrane is obtained. S14: Repeat the above transmission membrane iteration steps to gradually increase the area of ​​the nuclear micropore array and obtain an ordered nuclear pore membrane base film with consistent and regularly arranged nuclear micropore spacing.

3. The complete fabrication process of the ordered nuclear pore membrane with GEM probe and absorbing material according to claim 1, characterized in that, In step S2, the specific process of parameter splitting is as follows: Based on the different requirements of GEM probes and absorbing materials for the pore size, inner cone angle, and film thickness of the nuclear pore membrane, the ordered nuclear pore membrane base film is cut into a first sub-batch and a second sub-batch. The etching time and sensitization time parameters adapted to the GEM probe are set for the first sub-batch, and multiple sets of etching time and sensitization time parameters adapted to the absorbing material are set for the second sub-batch, so that the same base film batch is respectively guided to the preparation process of two types of products.

4. The complete fabrication process of the ordered nuclear pore membrane with GEM probe and absorbing material according to claim 1, characterized in that, In step S3, the specific process for preparing the conductive layer core-pore film and the insulating layer core-pore film is as follows: A conductive material film is selected as the substrate of the conductive layer core pore film, and an insulating material film is selected as the substrate of the insulating layer core pore film. The conductive material film and the insulating material film are subjected to particle bombardment, sensitization and chemical etching respectively according to the ordered core pore film preparation process in step S1 to obtain a conductive layer core pore film and an insulating layer core pore film with consistent core micropore spacing. Alternatively, after depositing conductive layers on both sides of an insulating film, neatly arranged nuclear micropores are punched on the film according to the process in step S1 to obtain a nuclear pore film that is conductive on both sides.

5. The complete fabrication process of the ordered nuclear pore membrane with GEM probe and absorbing material according to claim 1, characterized in that, In step S3, the specific process of stacking, aligning, and bonding the three nuclear pore membranes is as follows: Positioning and alignment marks are pre-made on the edges of the conductive layer core pore membrane and the insulating layer core pore membrane. During the stacking, the positioning and alignment marks are used to make the centers of the core micropores of the three layers of core pore membranes coincide one by one in the direction perpendicular to the membrane surface. After confirming the correspondence of the pore positions, interlayer bonding material is applied to the edge area of ​​the three layers of membrane. After curing, the three layers of membrane form an integral GEM probe composite membrane.

6. The complete fabrication process of the ordered nuclear pore membrane with GEM probe and absorbing material according to claim 4, characterized in that, The conductive material is at least one of copper, gold, or aluminum, and the insulating material is at least one of polyimide, polycarbonate, or polyester.

7. The complete fabrication process of the ordered nuclear pore membrane with GEM probe and absorbing material according to claim 1, characterized in that, In step S4, the specific process for preparing nuclear pore membranes with different pore sizes and inner cone angles is as follows: Different chemical etching times were set for each group of films in the second sub-batch. The longer the etching time, the larger the nuclear micropore diameter, thus obtaining multiple groups of nuclear pore films with gradient pore size distribution. Different sensitization times were set for each group of membranes. The longer the sensitization time, the larger the inner cone angle of the nuclear micropores, thus obtaining multiple groups of nuclear pore membranes with a gradient distribution of inner cone angles. By combining the pore size gradient with the inner cone angle gradient, multilayer nuclear pore membranes with different pore sizes and inner cone angle combinations can be obtained.

8. The complete fabrication process of the ordered nuclear pore membrane with GEM probe and absorbing material according to claim 1, characterized in that, In step S4, the specific process of interleaving and fixing the multilayer nuclear pore membranes is as follows: Multilayer nuclear pore membranes with different pore sizes and inner cone angles are stacked sequentially in order of increasing or decreasing pore size. During stacking, the nuclear micropore arrays of two adjacent nuclear pore membranes are offset from each other by half a pore spacing within the membrane surface, so that the nuclear micropore positions of adjacent membranes are staggered and arranged in an alternating manner. Interlayer fixing adhesive is applied to the edge region between adjacent membrane layers, and the layers are then pressed and cured to form a monolithic microwave absorbing material stack.

9. The complete fabrication process of the ordered nuclear pore membrane with GEM probe and absorbing material according to claim 8, characterized in that, The multilayer nuclear pore membrane has no fewer than three layers, and the offset directions between adjacent membrane layers are the same or alternate.

10. The complete fabrication process of the ordered nuclear pore membrane with GEM probe and absorbing material according to claim 1, characterized in that, It also includes the following steps: S5: Complete process quality inspection, the specific process is as follows: The one-to-one correspondence accuracy of the three-layer nuclear micropores in the GEM probe composite film was detected by scanning electron microscopy, and the cross-offset of the nuclear micropores in adjacent film layers in the microwave absorbing material stack was detected by scanning electron microscopy. When the detection result exceeds the preset accuracy range, feedback is provided to adjust the overlapping alignment parameter in step S3 or the interleaving offset parameter in step S4.

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