EMI electromagnetic shielding film and manufacturing method thereof

Abstract

The invention discloses an EMI electromagnetic shielding film and a manufacturing method thereof.The EMI electromagnetic shielding film comprises a transparent substrate base material and further comprises a conductive metal layer formed on the surface of the transparent substrate base material, and the conductive metal layer is provided with a wiring structure with a preset pattern; the manufacturing method of the EMI electromagnetic shielding film comprises the following steps: S1, providing a transparent substrate base material; s2, a transparent base material is stacked on the transparent substrate base material through a thermocompression bonding technology, and a composite base material is formed; s3, performing deep cutting on the composite base material by adopting laser to form a groove with a preset pattern; s4, a conductive metal layer is deposited on the surface of the cut composite base material through a magnetron sputtering method; the groove filling type conductive path is formed through laser depth-controlled cutting, the conductive metal layer is completely embedded into the surface of the transparent substrate base material, and compared with a traditional yellow light etching process, generation of a relief printing plate circuit is avoided, so that it is guaranteed that the mechanical property of the transparent substrate base material is uniform, and the impact resistance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic shielding films, specifically an EMI electromagnetic shielding film and its manufacturing method. Background Art

[0002] The problem of electromagnetic interference (EMI) has become an important challenge affecting the reliability of equipment and human health. Electromagnetic radiation almost covers all spaces of our lives, causing certain harm to the human body. At the same time, the complexity of the space electromagnetic environment is also prone to problems such as network crosstalk, communication identification misalignment, and equipment failures. Transparent EMI electromagnetic shielding films and their manufacturing methods can be installed in visible window areas such as glass and transparent plastic plates, greatly enhancing the shielding effect on electromagnetic radiation. Among them, the application demand for transparent shielding films in fields such as building facades, automotive electronics, and wearable devices has increased rapidly.

[0003] However, the conventional manufacturing methods of transparent EMI electromagnetic shielding films, such as the yellow light etching process, produce relief patterns. The protruding patterns are prone to uneven stress on the glass, affecting the mechanical properties of the glass and resulting in a decrease in the impact resistance. Summary of the Invention

[0004] The purpose of the present invention is to provide an EMI electromagnetic shielding film and its manufacturing method to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: An EMI electromagnetic shielding film and its manufacturing method, including a transparent substrate, and further including a conductive metal layer formed on the surface of the transparent substrate, the conductive metal layer having a wire structure with a predetermined pattern;

[0006] The manufacturing method of the EMI electromagnetic shielding film includes the following steps:

[0007] S1: Provide a transparent substrate with a thickness of 25 - 100 μm;

[0008] S2: Laminate a transparent substrate on the transparent substrate through a thermal lamination process to form a composite substrate, where the thickness of the transparent substrate is 2 - 10 μm and the surface adhesion strength is 0.5 - 5 N / cm;

[0009] S3: Use a laser with a wavelength of 1064 nm and a pulse width of 10 - 100 ps to deeply cut the composite substrate to form grooves with a predetermined pattern, and the cutting depth D1 satisfies D1 = D2 + D3, where D2 is the thickness of the transparent substrate and D3 is the preset thickness of the conductive metal layer;

[0010] S4: Deposit a conductive metal layer on the surface of the cut composite substrate by magnetron sputtering, and the deposition thickness D4 satisfies 0.5 μm ≤ D4 ≤ D3;

[0011] S5: Remove the transparent substrate by peeling, and retain the transparent substrate and the conductive metal layer with a groove filling structure on its surface.

[0012] Preferably, the line width W of the wiring structure satisfies 5μm ≤ W ≤ 50μm, and the adjacent wiring spacing S satisfies 10μm ≤ S ≤ 200μm; the total thickness D4 of the conductive metal layer satisfies 0.5μm ≤ D4 ≤ 5μm, and its surface roughness Ra ≤ 0.1μm.

[0013] Preferably, the transparent substrate is made of biaxially oriented polyethylene terephthalate, cycloolefin polymer, or transparent polyimide, and its thickness is 25 - 100μm; the material of the conductive metal layer is silver, copper, aluminum, or their alloys, and an antioxidant protective layer with a thickness of 2 - 20nm is provided on the surface of the metal layer.

[0014] Preferably, the wiring structure includes interconnected grid-shaped grooves, the side wall and the bottom surface of the groove form an angle of 70 - 110°, and the ratio of the bottom width W1 to the opening width W2 of the groove is 0.7 - 1.0.

[0015] Preferably, the transparent substrate is made of polymethyl methacrylate, polycarbonate, or a UV curable adhesive layer. The temperature of the hot pressing process is 80 - 150°C, the pressure is 0.2 - 1.5MPa, and the duration is 10 - 300s.

[0016] Preferably, the base vacuum of the magnetron sputtering process ≤ 5×Pa, the working gas pressure is 0.3 - 1.0Pa, the sputtering power is 2 - 10kW, the substrate temperature is controlled at 20 - 80°C, and the conductive metal layer is a multi-layer structure, including a chromium transition layer, a copper main layer, and a silver antioxidant layer arranged in sequence from the inside out.

[0017] Preferably, when D4 < D3, an electroplating process is used to thicken the conductive metal layer. The electroplating solution is a copper sulfate system or a potassium silver cyanide system, and the current density is 1 - 10A / dm 2 , and the electroplating time is 1 - 30 minutes to make the final thickness of the conductive layer reach D3.

[0018] Preferably, before the electroplating process, the conductive metal layer is treated by plasma cleaning. The argon flow rate is 50 - 200sccm, the RF power is 100 - 500W, and the treatment time is 1 - 5 minutes.

[0019] Preferably, a transparent protective layer is coated on the surface of the conductive metal layer, and the thickness of the protective layer is 1 - 10μm.

[0020] Preferably, the formed groove pattern includes first-direction traces and second-direction traces that are orthogonal to each other, forming a grid structure, where the width W3 of the first-direction traces is 5 - 20 μm, the width W4 of the second-direction traces is 8 - 30 μm, and the ratio of W3 to W4 is 0.6 - 1.5.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. The present invention forms a groove-filled conductive path through laser-controlled depth cutting, and the conductive metal layer is completely embedded in the surface of the transparent substrate material. Compared with the traditional yellow light etching process, the generation of relief patterns is avoided, thereby ensuring the uniform mechanical properties of the transparent substrate material and improving the impact resistance.

[0023] 2. The peelable design adopted by the present invention makes the transparent substrate easy to peel during the manufacturing process, reduces environmental pollution, and at the same time improves the recycling rate of materials. The multi-layer conductive metal layer deposited by magnetron sputtering has good adhesion and conductivity, meeting the usage requirements of the electromagnetic shielding film.

[0024] 3. The trace structure design adopted by the present invention makes the line width and spacing of the conductive metal layer moderate, which can not only ensure the electromagnetic shielding effect but also maintain high transparency, without affecting the appearance and use of the device. It is applicable to different types of transparent substrate materials and conductive metal materials, has strong adaptability, and can be widely applied to various electronic devices. Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of the composite substrate of the present invention.

[0026] Figure 2 It is a schematic structural diagram of the groove of the present invention.

[0027] Figure 3 It is a schematic structural diagram of the conductive metal layer of the present invention.

[0028] Figure 4 It is a schematic structural diagram of the EMI electromagnetic shielding film of the present invention.

[0029] Figure 5 It is a schematic structural diagram of the transparent protective layer of the present invention.

[0030] In the figure: transparent substrate material 1; transparent substrate 2; composite substrate 3; grid-shaped groove 31; conductive metal layer 4; transparent protective layer 5. Detailed Embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] Please refer to Figures 1 to 5 , the present invention provides a technical solution: an EMI electromagnetic shielding film and its manufacturing method, including a transparent substrate base material 1, and further including a conductive metal layer 4 formed on the surface of the transparent substrate base material 1, and the conductive metal layer 4 has a trace structure with a predetermined pattern;

[0033] The line width W of the trace structure satisfies 5μm ≤ W ≤ 50μm, and the adjacent trace spacing S satisfies 10μm ≤ S ≤ 200μm; the total thickness D4 of the conductive metal layer 4 satisfies 0.5μm ≤ D4 ≤ 5μm, and its surface roughness Ra ≤ 0.1μm.

[0034] The transparent substrate base material 1 is made of biaxially oriented polyethylene terephthalate, cycloolefin polymer, or transparent polyimide, and its thickness is 25 - 100μm; the material of the conductive metal layer 4 is silver, copper, aluminum, or their alloy, and an antioxidant protective layer with a thickness of 2 - 20nm is provided on the surface of the metal layer.

[0035] The trace structure includes a grid-like groove 31 that is interconnected, and the side wall and the bottom surface of the groove 31 form an angle of 70 - 110°, and the ratio of the bottom width W1 to the opening width W2 of the groove is 0.7 - 1.0.

[0036] The manufacturing method of the EMI electromagnetic shielding film includes the following steps:

[0037] S1: Provide a transparent substrate base material 1 with a thickness of 25 - 100μm;

[0038] S2: Laminate a transparent substrate 2 on the transparent substrate base material 1 through a thermal lamination process to form a composite substrate 3, where the thickness of the transparent substrate 2 is 2 - 10μm, and its surface adhesion strength is 0.5 - 5N / cm, forming a peelable sacrificial layer for subsequent laser etching and metal layer transfer.

[0039] The transparent substrate 2 is made of polymethyl methacrylate, polycarbonate, or a UV curable adhesive layer. The temperature of the thermal lamination process is 80 - 150°C, the pressure is 0.2 - 1.5MPa, and the duration is 10 - 300s.

[0040] S3: Use a laser with a wavelength of 1064 nm and a pulse width of 10 - 100 ps to deeply cut the composite substrate 3 to form a groove 31 with a predetermined pattern, where the cutting depth D1 satisfies D1 = D2 + D3, D2 is the thickness of the transparent substrate 2, and D3 is the preset thickness of the conductive metal layer;

[0041] Use a picosecond laser with a pulse width of 10 ps and a femtosecond laser with a pulse width of 500 fs for composite processing. The picosecond laser completes rough cutting, and the femtosecond laser refines the sidewalls. The included angle between the beam polarization direction and the wire routing direction is controlled within ±5° to reduce sidewall ripples.

[0042] The pattern of the formed groove 31 includes first - direction wire routing and second - direction wire routing that are orthogonal to each other, forming a grid structure. The width W3 of the first - direction wire routing is 5 - 20 μm, the width W4 of the second - direction wire routing is 8 - 30 μm, and the ratio of W3 to W4 is 0.6 - 1.5.

[0043] S4: Deposit a conductive metal layer 4 on the surface of the cut composite substrate 3 by magnetron sputtering. The deposition thickness D4 satisfies 0.5 μm ≤ D4 ≤ D3;

[0044] The base vacuum degree of the magnetron sputtering process is ≤ 5×Pa, the working gas pressure is 0.3 - 1.0 Pa, the sputtering power is 2 - 10 kW, the substrate temperature is controlled at 20 - 80°C. The conductive metal layer 4 is a multi - layer structure, including a chromium transition layer, a copper main layer, and a silver antioxidant layer arranged in sequence from the inside out. Fill the groove with conductive metal to form a continuous conduction path, and achieve high conductivity and antioxidant properties through the multi - layer structure.

[0045] S5: Peel off and remove the transparent substrate 2, leaving the transparent substrate 1 and the conductive metal layer 4 with a groove - filled structure on its surface. A transparent protective layer 5 is coated on the surface of the conductive metal layer 4, and the thickness of the protective layer 5 is 1 - 10 μm.

[0046] Adopt low - temperature peeling, from - 20°C to 0°C, to reduce the interfacial adhesion force, and apply ultrasonic assistance with a frequency of 28 kHz and a power of 50 - 200 W to promote interfacial separation.

[0047] When D4 < D3, use an electroplating process to thicken the conductive metal layer 4. The electroplating solution is a copper sulfate system or a potassium silver cyanide system, and the current density is 1 - 10 A / dm 2 , and the electroplating time is 1 - 30 minutes to make the final thickness of the conductive layer reach D3.

[0048] Before the electroplating process, perform plasma cleaning on the conductive metal layer 4. The argon flow rate is 50 - 200 sccm, the radio - frequency power is 100 - 500 W, and the treatment time is 1 - 5 minutes to remove the metal surface oxide layer and organic matter contamination and improve the adhesion of the electroplated layer.

[0049] The present invention forms a groove-filled conductive path through laser depth-controlled cutting, and the conductive metal layer is completely embedded in the surface of the transparent substrate. Compared with the traditional yellow light etching process, the generation of relief patterns is avoided, thereby ensuring the uniform mechanical properties of the transparent substrate and improving the impact resistance. The peelable design adopted makes the transparent substrate easy to peel off during the manufacturing process, reduces environmental pollution, and at the same time improves the recycling rate of materials. The multi-layer conductive metal layer deposited by magnetron sputtering has good adhesion and conductivity, meeting the usage requirements of the electromagnetic shielding film. The adopted wiring structure design makes the line width and spacing of the conductive metal layer moderate, which can not only ensure the electromagnetic shielding effect but also maintain high transparency without affecting the appearance and use of the device. It is applicable to different types of transparent substrate materials and conductive metal materials, has strong adaptability, and can be widely applied to various electronic devices.

[0050] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. EMI electromagnetic shielding film and its manufacturing method, including a transparent substrate, characterized in that: It also includes a conductive metal layer formed on the surface of the transparent substrate, wherein the conductive metal layer has a wiring structure of a predetermined pattern; The method for manufacturing an EMI electromagnetic shielding film comprises the following steps: S1: providing a transparent substrate having a thickness of 25-100 μm; S2: Laminating a transparent substrate on a transparent substrate by a thermal pressing process to form a composite substrate, wherein the transparent substrate has a thickness of 2-10 μm and a surface bonding strength of 0.5-5 N / cm; S3: using a laser with a wavelength of 1064nm and a pulse width of 10-100ps to deeply cut the composite substrate to form a groove with a predetermined pattern, and the cutting depth D1 satisfies D1=D2+D3, where D2 is the thickness of the transparent substrate and D3 is the preset thickness of the conductive metal layer; S4: depositing a conductive metal layer on the surface of the cut composite substrate by magnetron sputtering, wherein the deposition thickness D4 satisfies 0.5 μm≤D4≤D3; S5: stripping and removing the transparent substrate, leaving the transparent substrate and the conductive metal layer with the groove filling structure on the surface thereof.

2. The EMI electromagnetic shielding film and the method for manufacturing the same according to claim 1, characterized in that: The line width W of the routing structure satisfies 5μm≤W≤50μm, and the spacing S between adjacent routing lines satisfies 10μm≤S≤200μm; the total thickness D4 of the conductive metal layer satisfies 0.5μm≤D4≤5μm, and its surface roughness Ra≤0.1μm.

3. The EMI electromagnetic shielding film and the method for manufacturing the same according to claim 1, characterized in that: The transparent substrate base material is made of biaxially stretched polyethylene terephthalate, cycloolefin polymer, transparent polyimide, and has a thickness of 25-100 μm; the conductive metal layer is made of silver, copper, aluminum or their alloys, and an anti-oxidation protective layer with a thickness of 2-20 nm is provided on the surface of the metal layer.

4. The EMI electromagnetic shielding film and the method for manufacturing the same according to claim 1, characterized in that: The wiring structure includes interconnected grid-like grooves, the sidewalls of the grooves and the bottom surface form an angle of 70-110°, and the ratio of the groove bottom width W1 to the opening width W2 is 0.7-1.

0.

5. The EMI electromagnetic shielding film and the method for manufacturing the same according to claim 1, characterized in that: The transparent substrate is made of polymethyl methacrylate, polycarbonate or UV curing adhesive layer, and the temperature of the hot pressing process is 80-150° C., the pressure is 0.2-1.5 MPa, and the duration is 10-300 seconds.

6. The EMI electromagnetic shielding film and the method for manufacturing the same according to claim 1, characterized in that: The substrate vacuum degree of the magnetron sputtering process is ≤5×10 -3 Pa, the working gas pressure is 0.3-1.0 Pa, the sputtering power is 2-10 kW, the substrate temperature is controlled at 20-80°C, and the conductive metal layer is a multi-layer structure, including a chromium transition layer, a copper main layer and a silver anti-oxidation layer arranged in sequence from the inside to the outside.

7. The EMI electromagnetic shielding film and the method for manufacturing the same according to claim 1, characterized in that: When D4<D3, the conductive metal layer is thickened by electroplating process, the electroplating solution is copper sulfate system or silver potassium cyanide system, and the current density is 1-10A / dm 2 The electroplating time is 1-30 minutes, so that the final conductive layer thickness reaches D3.

8. The EMI electromagnetic shielding film and the method for manufacturing the same according to claim 7, characterized in that: Before the electroplating process, the conductive metal layer is subjected to plasma cleaning treatment, the argon gas flow rate is 50-200sccm, the radio frequency power is 100-500W, and the treatment time is 1-5 minutes.

9. The EMI electromagnetic shielding film and the method for manufacturing the same according to claim 1, characterized in that: The surface of the conductive metal layer is coated with a transparent protective layer, and the thickness of the protective layer is 1-10 μm.

10. The EMI electromagnetic shielding film and the method for manufacturing the same according to claim 1, characterized in that: The groove pattern formed includes mutually orthogonal first direction lines and second direction lines to form a grid structure, wherein the first direction line width W3 is 5-20 μm, the second direction line width W4 is 8-30 μm, and the ratio of W3 to W4 is 0.6-1.5.

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