Extreme-environment-resistant ultra-wideband microwave electromagnetic shielding metasurface film and preparation thereof

Abstract

The invention relates to the technical field of electromagnetic shielding materials, in particular to an ultra-wideband microwave electromagnetic shielding metasurface film resistant to an extreme environment and preparation of the ultra-wideband microwave electromagnetic shielding metasurface film. The five-layer structure is attached to the surface of the substrate and sequentially comprises a first metal Cr film, a Fe20Ni80 alloy film, a metal Cu film, a second metal Cr film and a metal Au film, the Fe20Ni80 alloy film is a rhombic periodic structure unit, and the metal Cu film is a rhombic nested rectangular periodic structure unit. The composite film structure is thin in overall thickness and light in weight, perfectly conforms to the development direction of high integration level, light weight and film formation of 6G communication equipment, the adopted multi-target magnetron sputtering coating and laser etching preparation technology is combined, accurate deposition of multiple layers of films and high-precision patterning of an FSS periodic structure can be achieved, the technology compatibility is high, and the cost is low. A reliable technical approach is provided for the consistency and batch preparation of the core structure, and the industrial application of the high-performance material is promoted.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic shielding materials technology, and more specifically, to ultra-wideband microwave electromagnetic shielding metasurface films resistant to extreme environments and their preparation. Background Technology

[0002] With the large-scale commercialization of fifth-generation mobile communication technology (5G), the technological evolution and application requirements for future 6G communication are gradually becoming clearer. According to international consensus, 6G communication will achieve leapfrog breakthroughs in spectrum resources, transmission bandwidth, integration density, and device form factor. Its core technological characteristics include multi-spectrum, high-bandwidth transmission, high integration of communication equipment, and ultra-thin and ultra-lightweight design. This requires the electronic material system supporting 6G to adapt to the ultra-wideband, high-efficiency electromagnetic shielding requirements with microwave and millimeter-wave as the core frequency bands. At the same time, due to the use of multi-frequency and wideband carriers, 6G systems will face more complex signal interference problems, especially in the wide frequency band from GHz to THz, where electromagnetic shielding effectiveness needs to reach over 100dB to ensure signal integrity and equipment reliability.

[0003] Currently, electromagnetic shielding materials widely used in 5G electronic devices mainly rely on highly conductive metal material systems such as Au, Ag, and Cu, specifically in the form of composite thin-film materials such as metal particles filled with polymer resin or independent metal films. However, when these materials are made into thin films, they generally suffer from problems such as narrow operating frequency bands and insufficient electromagnetic shielding effectiveness. Simply increasing the material thickness to improve shielding effectiveness will lead to a series of challenges, such as decreased film adhesion and significantly increased costs, making it difficult to meet the multiple performance and functional requirements of electromagnetic shielding materials in the 6G era, including low cost, lightweight, thin-film construction, high integration, wide bandwidth and high efficiency, and resistance to extreme service environments.

[0004] Therefore, developing a novel electromagnetic shielding composite thin film material that combines wide bandwidth and high shielding effectiveness in an ultra-thin thickness has become a key material issue that urgently needs to be addressed to promote the development and commercial application of 6G communication technology. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one aspect of this invention is to provide an ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments. The thin film has a five-layer structure, with the layers attached to the substrate surface in the following order: a first metal Cr thin film, Fe... 20 Ni 80 Alloy film, Cu film, Cr film and Au film, wherein Fe 20 Ni 80 The alloy film is a rhombic periodic structure unit, and the metal Cu film is a rhombic nested rectangular periodic structure unit.

[0006] Preferably, the thickness of the first metallic Cr film is 75nm-125nm.

[0007] Preferably, the Fe 20 Ni 80 The thickness of the alloy film is 100nm-300nm.

[0008] Preferably, the thickness of the Cu metal film is 15 μm - 19 μm.

[0009] Preferably, the thickness of the second metallic Cr film is 75nm-125nm.

[0010] Preferably, the thickness of the metal Au film is 4μm-6μm.

[0011] Preferably, the substrate is a PCB board or a ceramic board.

[0012] Another objective of this invention is to provide a method for preparing an ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments, the specific steps of which are as follows: S1. Deposition of the first metal Cr thin film: On the substrate surface, a first metal Cr thin film is deposited using a multi-target magnetron sputtering equipment with Cr as the sputtering target and the process conditions being a temperature of 280-320℃ and a sputtering power of 350W. S2. Deposition and etching of Fe 20 Ni 80 Alloy thin film: Fe is deposited on the surface of the first metal Cr thin film using a multi-target magnetron sputtering equipment. 20 Ni 80 The alloy was used as the sputtering target, and the process conditions were: temperature 180-220℃, sputtering power 1500W, and Fe deposition. 20 Ni 80 The alloy thin film was etched with a rhombic periodic structure unit FSS pattern using a laser etching device. The laser source wavelength was 1064nm, the processing laser frequency was 200kHz, the current was 30%, the focal length was 8.65mm, and the processing speed was 2mm / s. S3. Deposited metal Cu thin film: in Fe 20 Ni 80 The alloy thin film surface was deposited using a multi-target magnetron sputtering deposition equipment with Cu as the sputtering target. The process conditions were: temperature 180-220℃, sputtering power 250W. A metal Cu thin film was deposited, and a diamond-shaped nested rectangular periodic structure unit (FSS) pattern was etched using a laser etching equipment with a laser source wavelength of 1064nm, a processing laser frequency of 200kHz, a current of 30%, a focal length of 8.65mm, and a processing speed of 2mm / s. S4. Deposition and etching of the second metal Cr thin film: A second metal Cr thin film is deposited on the surface of the metal Cu thin film using a multi-target magnetron sputtering equipment with Cr as the sputtering target. The process conditions are a temperature of 280-320℃ and a sputtering power of 350W. S5. Deposition of Au metal thin film: Using a multi-target magnetron sputtering deposition equipment on the surface of the second metal Cr thin film, with Au as the sputtering target, the process conditions are a temperature of 180-220℃ and a sputtering power of 350W, to deposit an Au metal thin film to obtain an ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments.

[0013] Preferably, the multi-target magnetron sputtering coating equipment uses Ar as the sputtering process gas, and the Ar flow rate is 50-55 SCCM.

[0014] Preferably, the sputtering target material is Cr, Fe 20 Ni 80 The purity of the alloy, Cu, and Au is 99.99%.

[0015] The beneficial effects of this invention are as follows: Ultra-high shielding efficiency in ultra-wide frequency bands has been achieved: By organically combining a double-layer frequency selective surface (FSS) periodic structure (Cu rhomboid nested rectangular units and Fe20Ni80 rhomboid units) with a multilayer conductive and magnetic thin film, this design breaks through the limitation of skin depth of a single material. It synergistically utilizes the electromagnetic wave reflection and resonant absorption mechanism. Under the premise that the total thickness of the film is ≤30μm, the electromagnetic shielding efficiency can be stably maintained at over 100dB in the ultra-wide microwave and millimeter wave frequency band from 0.1GHz to 75GHz. This effectively solves the core contradiction of existing thin film materials in terms of narrow frequency band and low shielding efficiency when they are made thinner, and meets the urgent need of 6G communication for wideband and high-efficiency shielding.

[0016] Significantly improved material tolerance to extreme environments: The innovative design of a chemically stable and corrosion-resistant Au film as the outermost layer enables the composite film to maintain excellent electromagnetic properties while possessing outstanding environmental reliability. Tests have verified that this structure can withstand extreme aerospace service conditions such as -196℃, 300℃, and oxygen atom environments, thereby expanding the application potential of ultrathin film shielding materials in harsh environments such as aerospace and high-end equipment.

[0017] Combining excellent integration adaptability and process feasibility, the composite thin film structure of this invention is thin and lightweight, perfectly aligning with the development trend of high integration, lightweight, and thin-film technology in 6G communication equipment. The multi-target magnetron sputtering coating combined with laser etching process enables precise deposition of multilayer thin films and high-precision patterning of FSS periodic structures. The strong process compatibility provides a reliable technical approach for the consistency and mass production of the core structure, facilitating the industrial application of this high-performance material.

[0018] Additional aspects and advantages of the invention will become apparent from the description which follows, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the ultra-wideband microwave electromagnetic shielding metasurface thin film structure of the present invention, which is resistant to extreme environments; Figure 2 This is the FSS structural unit pattern of the metal Cu thin film of the present invention; Figure 3 This is the Fe of the present invention 20 Ni 80 Alloy thin film FSS structural unit pattern; Figure 4 This is a test curve of the shielding effectiveness of the ultra-wideband microwave electromagnetic shielding metasurface film resistant to extreme environments in Embodiment 1 of the present invention; Figure 5 This is a test curve of the shielding effectiveness of the ultra-wideband microwave electromagnetic shielding metasurface film resistant to extreme environments in Embodiment 2 of the present invention; in, Figure 1 The correspondence between the reference numerals and component names in the attached drawings is as follows: 1 is the substrate, 2 is the first metallic Cr thin film, and 3 is Fe. 20 Ni 80 Alloy film, 4 is a Cu metal film, 5 is a second metal Cr film, and 6 is a Au metal film. Detailed Implementation

[0020] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0022] Example 1 S1. Deposition of the first metallic Cr thin film: On the surface of a 2mm thick PCB board, a 100nm first metallic Cr thin film is deposited using a multi-target magnetron sputtering coating equipment with Cr of 99.99% purity as the sputtering target and Ar as the sputtering process gas. The process conditions are: temperature of 280-320℃, sputtering power of 350W, and Ar flow rate of 50-55SCCM. S2. Deposition and etching of Fe 20 Ni 80 Alloy thin film: A multi-target magnetron sputtering deposition device was used on the surface of the first metal Cr thin film to deposit Fe with a purity of 99.9%. 20 Ni 80 The alloy was used as the sputtering target, Ar was used as the sputtering process gas, and the process conditions were: temperature 180-220℃, sputtering power 1500W, Ar flow rate 50-55 SCCM, and 200 nm Fe deposition. 20 Ni 80 The alloy thin film was etched with a rhombic periodic structure unit FSS pattern using a laser etching device. The laser source wavelength was 1064nm, the processing laser frequency was 200kHz, the current was 30%, the focal length was 8.65mm, and the processing speed was 2mm / s. S3. Deposited metal Cu thin film: in Fe 20 Ni 80 The alloy thin film surface was deposited using a multi-target magnetron sputtering equipment with 99.9% pure copper as the sputtering target and Ar as the sputtering process gas. The process conditions were: temperature 180-220℃, sputtering power 250W, Ar flow rate 50-55SCCM, and a 17μm Cu thin film was deposited. A rhombic nested rectangular periodic structure unit FSS pattern was then etched using a laser etching equipment with a laser source wavelength of 1064nm, a processing laser frequency of 200kHz, a current of 30%, a focal length of 8.65mm, and a processing speed of 2mm / s. S4. Deposition and etching of the second metal Cr thin film: A 10 nm second metal Cr thin film is deposited on the surface of the metal Cu thin film using a multi-target magnetron sputtering equipment with Cr of 99.99% purity as the sputtering target and Ar as the sputtering process gas. The process conditions are: temperature of 280-320℃, sputtering power of 350W, and Ar flow rate of 50-55SCCM. S5. Deposition of Au metal thin film: Using a multi-target magnetron sputtering deposition equipment on the surface of the second metal Cr thin film, Au with a purity of 99.99% is used as the sputtering target, Ar is used as the sputtering process gas, and the process conditions are: temperature of 180-220℃, sputtering power of 350W, Ar flow rate of 50-55SCCM, a 5μm metal Au thin film is deposited to obtain an ultra-wideband microwave electromagnetic shielding metasurface film resistant to extreme environments.

[0023] Example 2 S1. Deposition of the first metallic Cr thin film: A 100nm first metallic Cr thin film was deposited on the surface of a 2mm thick alumina ceramic plate using a multi-target magnetron sputtering coating equipment, with Cr of 99.99% purity as the sputtering target and Ar as the sputtering process gas. The process conditions were: temperature 280-320℃, sputtering power 350W, Ar flow rate 50-55SCCM. S2. Deposition and etching of Fe 20 Ni 80 Alloy thin film: A multi-target magnetron sputtering deposition device was used on the surface of the first metal Cr thin film to deposit Fe with a purity of 99.9%. 20 Ni 80 The alloy was used as the sputtering target, Ar was used as the sputtering process gas, and the process conditions were: temperature 180-220℃, sputtering power 1500W, Ar flow rate 50-55 SCCM, and 200 nm Fe deposition. 20 Ni 80 The alloy thin film was etched with a rhombic periodic structure unit FSS pattern using a laser etching device. The laser source wavelength was 1064nm, the processing laser frequency was 200kHz, the current was 30%, the focal length was 8.65mm, and the processing speed was 2mm / s. S3. Deposited metal Cu thin film: in Fe 20 Ni 80 The alloy thin film surface was deposited using a multi-target magnetron sputtering equipment with 99.9% pure copper as the sputtering target and Ar as the sputtering process gas. The process conditions were: temperature 180-220℃, sputtering power 250W, Ar flow rate 50-55SCCM, and a 17μm Cu thin film was deposited. A rhombic nested rectangular periodic structure unit FSS pattern was then etched using a laser etching equipment with a laser source wavelength of 1064nm, a processing laser frequency of 200kHz, a current of 30%, a focal length of 8.65mm, and a processing speed of 2mm / s. S4. Deposition and etching of the second metal Cr thin film: A 10 nm second metal Cr thin film is deposited on the surface of the metal Cu thin film using a multi-target magnetron sputtering equipment with Cr of 99.99% purity as the sputtering target and Ar as the sputtering process gas. The process conditions are: temperature of 280-320℃, sputtering power of 350W, and Ar flow rate of 50-55SCCM. S5. Deposition of Au metal thin film: Using a multi-target magnetron sputtering deposition equipment on the surface of the second metal Cr thin film, Au with a purity of 99.99% is used as the sputtering target, Ar is used as the sputtering process gas, and the process conditions are: temperature of 180-220℃, sputtering power of 350W, Ar flow rate of 50-55SCCM, a 5μm metal Au thin film is deposited to obtain an ultra-wideband microwave electromagnetic shielding metasurface film resistant to extreme environments.

[0024] Testing and Experiment The shielding effectiveness test results using Embodiment 1 and Embodiment 2 of the present invention are shown in Table 1 below.

[0025] In Case Study 1, a composite film material with a thickness of 22.4 μm was fabricated on one side of a 2 mm thick PCB board, achieving a shielding effectiveness of 102.3 dB to 137.2 dB in the 0.1 GHz to 75 GHz frequency band (see Table 1). In Case Study 2, a composite film material with a thickness of 22.4 μm was fabricated on one side of a 2 mm thick alumina ceramic plate, achieving a shielding effectiveness of 103.6 dB to 136.7 dB in the 0.1 GHz to 75 GHz frequency band (see Table 1). The corresponding shielding effectiveness test graphs in Table 1 are shown below. Figure 4 and Figure 5 .

[0026] Table 1. Shielding effectiveness of ultra-wideband microwave electromagnetic shielding metasurface films resistant to extreme environments. The experiment used a circular sample with a diameter of 150 mm for deep cryogenic, high-temperature, and oxygen atom stripping tests: The deep cryogenic test was conducted according to GJB150.4A, immersing the test sample in liquid nitrogen at -196℃ for 24 hours. After the low-temperature test, no blistering or detachment was observed on the sample. The high-temperature test was conducted according to GJB150.3A, at 300℃ for 48 hours. After the high-temperature test, no blistering or detachment was observed on the sample. The oxygen atom stripping test was conducted according to GJB2502.9-2015, with an atomic oxygen flux density of 5.0 × 10⁻⁶. 15 atoms / (cm 2 •s), exposed for 10 hours. After the atomic oxygen peel test, the sample showed no bubbling or peeling. The results are shown in Table 2 below.

[0027] Table 2. Test Results of Ultra-Wideband Microwave Electromagnetic Shielding Metasurface Thin Films with Extreme Service Conditions in Aerospace Environments Tests have verified that this structure can withstand extreme aerospace service conditions such as -196°C, 300°C, and oxygen atom environments, thus expanding the application potential of ultrathin film shielding materials in harsh environments such as aerospace and high-end equipment.

[0028] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A superwideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments, characterized in that: The film has a 5-layer structure, and the layers attached to the substrate surface in the following order are: a first metal Cr film, Fe... 20 Ni 80 Alloy film, Cu film, Cr film and Au film, wherein Fe 20 Ni 80 The alloy film is a rhombic periodic structure unit, and the metal Cu film is a rhombic nested rectangular periodic structure unit.

2. The ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments according to claim 1, characterized in that: The thickness of the first metallic Cr film is 75nm-125nm.

3. The ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments according to claim 1, characterized in that: The Fe 20 Ni 80 The thickness of the alloy film is 100nm-300nm.

4. The ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments according to claim 1, characterized in that: The thickness of the Cu thin film is 15μm-19μm.

5. The ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments according to claim 1, characterized in that: The thickness of the second metallic Cr film is 75nm-125nm.

6. The ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments according to claim 1, characterized in that: The thickness of the Au thin film is 4μm-6μm.

7. The ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments according to claim 1, characterized in that: The substrate is a PCB board or a ceramic board.

8. The method for preparing an ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments according to claim 1, characterized in that: The specific steps of the preparation method are as follows: S1. Deposition of the first metal Cr thin film: On the substrate surface, a first metal Cr thin film is deposited using a multi-target magnetron sputtering equipment with Cr as the sputtering target and the process conditions being a temperature of 280-320℃ and a sputtering power of 350W. S2. Deposition and etching of Fe 20 Ni 80 Alloy thin film: Fe is deposited on the surface of the first metal Cr thin film using a multi-target magnetron sputtering equipment. 20 Ni 80 The alloy was used as the sputtering target, and the process conditions were: temperature 180-220℃, sputtering power 1500W, and Fe deposition. 20 Ni 80 The alloy thin film was etched with a rhombic periodic structure unit FSS pattern using a laser etching device. The laser source wavelength was 1064nm, the processing laser frequency was 200kHz, the current was 30%, the focal length was 8.65mm, and the processing speed was 2mm / s. S3. Deposited metal Cu thin film: in Fe 20 Ni 80 The alloy thin film surface was deposited using a multi-target magnetron sputtering deposition equipment with Cu as the sputtering target. The process conditions were: temperature 180-220℃, sputtering power 250W. A metal Cu thin film was deposited, and a diamond-shaped nested rectangular periodic structure unit (FSS) pattern was etched using a laser etching equipment with a laser source wavelength of 1064nm, a processing laser frequency of 200kHz, a current of 30%, a focal length of 8.65mm, and a processing speed of 2mm / s. S4. Deposition and etching of the second metal Cr thin film: A second metal Cr thin film is deposited on the surface of the metal Cu thin film using a multi-target magnetron sputtering equipment with Cr as the sputtering target. The process conditions are a temperature of 280-320℃ and a sputtering power of 350W. S5. Deposition of Au metal thin film: Using a multi-target magnetron sputtering deposition equipment on the surface of the second metal Cr thin film, with Au as the sputtering target, the process conditions are a temperature of 180-220℃ and a sputtering power of 350W, to deposit an Au metal thin film to obtain an ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments.

9. The method for preparing an ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments according to claim 8, characterized in that: The multi-target magnetron sputtering coating equipment uses Ar as the sputtering process gas, with an Ar flow rate of 50-55 SCCM.

10. The method for preparing an ultra-wideband microwave electromagnetic shielding metasurface thin film resistant to extreme environments according to claim 8, characterized in that: The sputtering target material Cr, Fe 20 Ni 80 The purity of the alloy, Cu, and Au is 99.99%.

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