Composite metal foil and metal-clad laminated plate

Abstract

The invention discloses a composite metal foil and a metal-clad laminated plate, the composite metal foil comprises a substrate layer and a resistance layer, the resistance layer is laminated on one side of the substrate layer, the resistance layer comprises magnetic particles, and the proportion of the magnetic particles in the resistance layer is 5-15 wt%. According to the invention, the magnetic particles are arranged in the resistive layer, and the magnetic loss mechanism of the magnetic particles is utilized, so that the high-frequency interference suppression capability is improved, the parasitic inductance and capacitance generated by the resistive layer at high frequency are effectively reduced, and the reliability of signal transmission is ensured; meanwhile, resistance drift in a high-temperature environment can be effectively compensated by utilizing the Curie temperature characteristic of the magnetic particles, so that temperature drift is inhibited, and the reliability of signal transmission is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic information materials, in particular to a composite metal foil and a metal-clad laminate. Background Art

[0002] As electronic devices become increasingly miniaturized, lightweight, and highly integrated, the resistor components within them have evolved from traditional plug-in resistors with pins to surface-mount resistors and finally embedded resistors, gradually becoming thinner and lighter. The process for using an embedded resistor is roughly as follows: a composite metal foil is attached to a circuit board, and then an etching process is used to create the embedded resistor.

[0003] The composite metal foil commonly used in existing circuit boards consists of a base layer and a resistor layer stacked in sequence. The resistor layer, facing away from the base layer, is pressed against the circuit board and then etched to create circuitry, effectively embedding the resistors within the board. However, during the implementation of this prior art, the inventors discovered that high-frequency circuits are prone to parasitic inductance and capacitance, which can lead to signal distortion and energy loss. Furthermore, the temperature coefficient of resistance (TCR) of the resistor material is less stable at high temperatures, seriously impacting signal transmission reliability.

[0004] In order to solve the above problems, it is urgent to develop a composite metal foil and metal-clad laminate that can eliminate circuit parasitic inductance and capacitance and have a relatively stable resistance temperature coefficient to ensure signal transmission reliability. Summary of the Invention

[0005] The purpose of the embodiments of the present invention is to provide a composite metal foil that can eliminate parasitic inductance and capacitance of a circuit and has a relatively stable temperature coefficient of resistance, thereby ensuring signal transmission reliability.

[0006] To achieve the above objectives, a first aspect of an embodiment of the present invention provides a composite metal foil, comprising a base layer and a resistor layer, wherein the resistor layer is stacked on one side of the base layer, and the resistor layer comprises magnetic particles, and the magnetic particles account for 5-15wt% of the resistor layer.

[0007] Optionally, the magnetic particles include at least one of NiFe2O4 or Fe3O4.

[0008] Optionally, the particle size of the magnetic particles is 10-50 nm.

[0009] Optionally, the particle size range of the magnetic particles is less than or equal to 10%.

[0010] Optionally, the resistance temperature coefficient of the resistance layer is less than or equal to 50 ppm / °C.

[0011] Optionally, the sheet resistance uniformity of the resistance layer is less than or equal to 10%.

[0012] Optionally, the resistance layer includes at least one element of Ni, Co, Mo, Cr, Mg, Fe, Sn, Ti, Sn, and C, or the resistance layer includes at least one element of Ni, Co, Mo, Cr, Mg, Fe, Sn, Ti, Sn, and C and at least one element of P, Si, O, and N.

[0013] Optionally, the base layer has a thickness of 5 μm to 50 μm.

[0014] Optionally, the anti-oxidation layer is stacked on a side of the base layer away from the resistance layer.

[0015] To achieve the above-mentioned object, a second aspect of an embodiment of the present invention provides a metal-clad laminate, wherein the metal-clad laminate includes the composite metal foil described in any one of the above-mentioned embodiments.

[0016] Compared with the existing technology, the beneficial effect of the embodiments of the present invention is that by setting a resistance layer on the base layer and setting magnetic particles in the resistance layer, the magnetic particles account for 5-15wt% of the resistance layer, and utilizing the magnetic loss mechanism of the magnetic particles (such as eddy current loss and natural resonance), the high-frequency interference suppression capability is improved, and the parasitic inductance and capacitance generated by the resistance layer at high frequency are effectively reduced, thereby ensuring the reliability of signal transmission.

[0017] On the other hand, by utilizing the Curie temperature characteristics of magnetic particles and realizing adaptive adjustment of resistance value through magnetocaloric effect, resistance drift in high temperature environment can be effectively compensated, thereby suppressing temperature drift and ensuring the reliability of signal transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a first composite metal foil provided by an embodiment of the present invention;

[0019] Figure 2 It is a schematic structural diagram of the second composite metal foil provided in an embodiment of the present invention.

[0020] Among them, 1. base layer; 2. resistance layer; 21. magnetic particles; 3. anti-oxidation layer. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0022] In the description of the specification and claims, it should be understood that the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present invention.

[0023] Furthermore, the terms "first," "second," and so on, in the specification and claims, are used solely for descriptive purposes to distinguish between identical technical features and are not to be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referenced, nor do they necessarily describe a sequential or chronological order. The terms are interchangeable where appropriate. Thus, a feature qualified as "first" or "second" may explicitly or implicitly include at least one of those features.

[0024] See Figure 1 , Figure 1 The figure is a schematic structural diagram of a composite metal foil according to an embodiment of the present invention. The composite metal foil according to an embodiment of the present invention comprises: a base layer 1 and a resistor layer 2, wherein the resistor layer 2 is laminated on one side of the base layer 1 and includes magnetic particles 21, wherein the magnetic particles 21 account for 5-15 wt% of the resistor layer 2.

[0025] It is worth noting that in practical applications of composite metal foil, for example, in the field of circuit boards, the resistance layer 2 of the composite metal foil is pressed onto the substrate of the circuit board, and the circuit is first made by acid etching, and then the base layer 1 is etched alkaline to form the required circuit; for example, when used in the field of electronic material production, the resistance layer 2 of the composite metal foil is pressed onto a composite material to make a flexible copper clad laminate.

[0026] In an embodiment of the present invention, the base layer 1 plays a conductive role, and the circuit is formed by etching. The thickness of the base layer 1 is 5μm~50μm. By setting the thickness of the base layer 1 to 5μm~50μm, the poor conductivity of the circuit and the appearance of pinholes due to the base layer 1 being too thin will not occur, thereby affecting the conductive function of the circuit; at the same time, the circuit will not be too hard and the bending performance will be poor due to the base layer 1 being too thin, thereby affecting the assembly of the circuit board. Therefore, setting the thickness of the base layer 1 to 5μm~50μm can not only ensure the conductive function of the circuit, but also prevent abnormalities such as rebound and circuit breakage during assembly of the circuit board, thereby ensuring the quality reliability and processing stability of the circuit. Furthermore, the material of the base layer 1 includes at least one of the following metal elements: nickel, aluminum, titanium, zinc, iron, and copper. For example, in the buried copper foil, the material of the base layer 1 is usually copper.

[0027] In embodiments of the present invention, resistor layer 2 functions to control resistance. In circuit board applications, the composite metal foil resistor layer 2 is laminated to the circuit board substrate. Circuitry is first formed through acid etching, followed by alkaline etching of the base layer 1 to achieve the desired resistor size and value, effectively embedding the resistor within the circuit board. However, during implementation of this prior art, the inventors discovered that high-frequency circuits are prone to parasitic inductance and capacitance, which can lead to signal distortion and energy loss. Furthermore, the temperature coefficient of resistance (TCR) of the resistor material is less stable at high temperatures, severely impacting signal transmission reliability. Therefore, to address these signal distortion and energy loss issues, embodiments of the present invention incorporate magnetic particles 21 within the resistor layer 2, comprising 5-15% by weight. The magnetic loss mechanisms of the magnetic particles 21 (such as eddy current loss and natural resonance) are utilized to improve high-frequency interference suppression capabilities, effectively reducing the parasitic inductance and capacitance generated by the resistor layer 2 at high frequencies and ensuring reliable signal transmission. On the other hand, by utilizing the Curie temperature characteristics of the magnetic particles 21 and realizing adaptive adjustment of the resistance value through the magnetocaloric effect, the resistance drift in a high temperature environment can be effectively compensated, thereby suppressing the temperature drift and effectively reducing the parasitic inductance and capacitance generated by the resistance layer at high frequency, thereby ensuring the reliability of signal transmission.

[0028] As a preferred embodiment, the resistance layer 2 includes at least one element of Ni, Co, Mo, Cr, Mg, Fe, Sn, Ti, Sn, and C, or the resistance layer 2 includes at least one element of Ni, Co, Mo, Cr, Mg, Fe, Sn, Ti, Sn, and C and at least one element of P, Si, O, and N.

[0029] Preferably, the resistance layer 2 includes Ni and P. It is worth noting that the resistance layer 2 in the embodiment of the present invention includes Ni and P, Ni is a conductor, and P is a non-conductor. By adjusting the ratio of Ni and P, functional layers 2 with different resistance values ​​can be obtained, which can cover a wider range of applications.

[0030] In an embodiment of the present invention, the resistive layer 2 is fabricated by combining one or more of the following production methods: sputtering, evaporation, electroplating, and chemical plating, with the layers being stacked layer by layer on a substrate. Sputtering and evaporation are physical methods with simple processes and easy control. When combined with other methods, the dispersion of the magnetic particles 21 can be easily controlled. The magnetic field-assisted sputtering process aligns the magnetic particles, increasing the magnetic permeability to 10-15, optimizing the inductance distribution in high-frequency circuits, and reducing the parasitic inductance to 0.5-1 nH / mm².

[0031] Specifically, in an embodiment of the present invention, the magnetic particles 21 account for 5-15wt% of the resistor layer 2. The proportion of magnetic particles in the resistor layer 2 is limited to an appropriate range. A too low content of magnetic particles 21 makes it difficult to effectively stimulate magnetic loss in the resistor layer 2, weakening the dominant effect of magnetic loss. A mechanism relying on dielectric loss accounts for too high a proportion, which may not meet high-frequency anti-interference requirements. Furthermore, a low content of magnetic particles 21 may not effectively regulate the temperature coefficient of resistance, limiting the magnetocaloric effect and making it difficult to compensate for resistance drift in high-temperature environments. A high content of magnetic particles 21, on the other hand, can easily lead to agglomeration due to magnetic attraction, causing localized fractures in the conductive network and reduced resistance uniformity. A high proportion of magnetic particles 21 significantly increases the magnetic permeability of the material, exacerbating impedance mismatch. Furthermore, a high content of magnetic particles 21 can easily induce eddy current losses in the GHz frequency band, reducing the stability of the magnetic permeability. Therefore, the present invention limits the proportion of magnetic particles 21 to 5-15wt%. Within this range, the magnetic particles 21 can not only effectively contribute to magnetic loss, but also optimize impedance matching through the dielectric-magnetic synergistic effect, effectively reducing the parasitic inductance and capacitance generated by the resistor layer at high frequencies, ensuring the reliability of signal transmission. At the same time, the particles are evenly dispersed and not easily agglomerated, which affects the uniformity of resistance. They also have a certain magnetocaloric effect, which can effectively compensate for resistance drift in high temperature environments and have good temperature stability. Optionally, the proportion of magnetic particles 21 in the resistor layer 2 can be any one of 5wt%, 8wt%, 10wt%, 12wt% or 15wt%, or an interval formed by any two of these values.

[0032] In an embodiment of the present invention, the magnetic particles 21 include at least one of NiFe2O4 or Fe3O4. NiFe2O4 has a face-centered cubic inverse spinel structure, in which Fe³⁺ occupies tetrahedral and octahedral sites, and Ni²⁺ occupies octahedral sites. This structure imparts excellent ferromagnetism and high resistivity, outstanding high-temperature resistance, and thermal stability exceeding 1000K. Fe3O4 has a spinel structure, in which Fe³⁺ and Fe²⁺ occupy tetrahedral and octahedral sites, respectively, forming ferrimagnetism. Its crystal form is face-centered cubic. Fe3O4 is superparamagnetic (no remanence) and exhibits a good magnetocaloric effect (heat generation in an alternating magnetic field). The combination of the magnetic particles 21 and the resistor layer 2 provides high-frequency characteristics and resistance stability, effectively reducing the parasitic inductance and capacitance generated by the resistor layer at high frequencies, thereby ensuring reliable signal transmission.

[0033] Furthermore, the particle size of the magnetic particles 21 is 10-50 nm. By limiting the particle size of the magnetic particles 21 to an appropriate range, on the one hand, the eddy current effect generated by high frequency will not be suppressed due to the particle size being too small, and the magnetic particles 21 will easily agglomerate, thereby causing local breakage of the conductive network and reducing the uniformity of resistance. On the other hand, the specific surface area of ​​the magnetic particles 21 will not be too small due to the particle size being too large, resulting in poor heat dissipation and being detrimental to optimizing temperature stability. Therefore, limiting the particle size of the magnetic particles 21 to 10-50 nm is conducive to suppressing the eddy current effect at high frequency, reducing the imaginary part of the magnetic permeability by more than 30%, and reducing energy loss. At the same time, the large specific surface area of ​​the magnetic particles 21 accelerates heat diffusion. Combined with the magnetocaloric effect, the TCR of the resistor layer is significantly reduced, and excellent temperature stability is achieved. Optionally, the particle size of the magnetic particles 21 is any one of 10 nm, 20 nm, 30 nm, 40 nm, or 50 nm, or an interval formed by any two values.

[0034] For example, the magnetic particles 21 have a particle size of 15 nm and a specific surface area of ​​80 m² / g, which reduces the TCR of the resistor layer from ±200 ppm / °C to below ±50 ppm / °C, and the resistance fluctuation at high temperature (150°C) is less than 2%.

[0035] It should be noted that, in the embodiment of the present invention, the magnetic particles 21 can be surface treated to further optimize the agglomeration problem of the particles so that the magnetic particles 21 can be evenly dispersed. Exemplarily, the surface treatment method includes at least one of surface active treatment, coupling treatment, and oxidation treatment.

[0036] Furthermore, in an embodiment of the present invention, the particle size range of the magnetic particles 21 is less than or equal to 10%. By limiting the particle size range of the magnetic particles 21 to an appropriate range, the magnetic response behavior of the magnetic particles 21 is highly consistent, and the fluctuation range of the magnetic permeability is significantly reduced. At the same time, the uniform particle size distribution reduces local electric field distortion, making the deposition rate of the magnetic particles 21 more uniform, significantly reducing the thickness error of the resistor layer 2, and effectively improving the uniformity of the resistor layer 2. Therefore, limiting the particle size range of the magnetic particles 21 to less than or equal to 10% significantly improves the uniformity of the square resistance of the resistor layer 2 and enhances process stability, thereby improving the reliability of the composite metal foil in high-frequency, high-temperature scenarios, effectively reducing the parasitic inductance and capacitance generated by the resistor layer at high frequencies, and ensuring reliable signal transmission.

[0037] It should be noted that the calculation process of the particle size range of the magnetic particles 21 is as follows: grind the slices perpendicular to the thickness direction, observe the cross-section of the resistance layer 2, and within the set observation range, arbitrarily select 10 magnetic particles 21 for particle size measurement, subtract the maximum value from the minimum value, and calculate the average value of the above 10 particle sizes. Then, divide the difference by the average value to obtain the particle size range of the magnetic particles 21.

[0038] In the embodiment of the present invention, the resistance temperature coefficient of the resistance layer 2 is less than or equal to 50 ppm / °C. The resistance temperature coefficient of the resistance layer 2 is less than or equal to 50 ppm / °C, and the magnetic particles 21 utilize their own Curie temperature characteristics.

[0039] The magnetocaloric effect makes it easier to achieve adaptive adjustment of the resistance value, effectively compensating for resistance drift in high-temperature environments with greatly improved accuracy, thereby accurately suppressing temperature drift and ensuring the reliability of signal transmission.

[0040] Furthermore, in an embodiment of the present invention, the uniformity of the square resistance of the resistor layer 2 is less than or equal to 10%. A more uniform square resistance of the resistor layer 2 results in a more consistent potential gradient and a more uniform electric field distribution. This can reduce the "hotspot" effect of local parasitic capacitance in high-frequency applications, thereby avoiding signal distortion, energy loss, or device failure.

[0041] It should be noted that the calculation method for the square resistance uniformity of the resistor layer 2 is: 10 square resistance values ​​are obtained by arbitrary testing on the resistor layer, and the difference between the maximum and minimum values ​​among the 10 square resistance values ​​is taken, and the average value of the 10 square resistance values ​​is calculated, and then the square resistance uniformity can be obtained by dividing the difference by the average value.

[0042] See also Figure 2 , Figure 2 This is a schematic diagram of the structure of another composite metal foil provided by an embodiment of the present invention. In order to better protect the composite metal foil, in an embodiment of the present invention, the side of the base layer 1 away from the resistor layer 2 is further laminated with the anti-oxidation layer 3 to prevent the composite metal foil from undergoing an oxidation reaction before lamination, thereby affecting its quality. It is understandable that if the anti-oxidation layer 3 is not present, the side of the base layer 1 away from the resistor layer 2 is easily oxidized under conditions such as temperature, water vapor, and corrosive gases, resulting in abnormal circuit processing; therefore, in an embodiment of the present invention, the anti-oxidation layer 3 is provided on the side of the base layer 1 away from the resistor layer 2, which can prevent substances such as temperature, water vapor, and corrosive gases from undergoing an oxidation reaction with the side of the base layer 1 away from the resistor layer 2, thereby protecting the composite metal foil and improving its quality performance.

[0043] Specifically, the type of the anti-oxidation layer 3 is not limited by the material of the resistance layer 2 , and the anti-oxidation layer 3 is selected from at least one of an organic anti-oxidation layer, an inorganic anti-oxidation layer, and a metal anti-oxidation layer.

[0044] A second aspect of the embodiments of the present invention provides a metal-clad laminate, comprising the composite metal foil as described in any one of the first aspects.

[0045] The composite metal foil and metal-clad laminate provided by the embodiments of the present invention have the following beneficial effects: by providing a resistor layer 2 on a base layer 1, and providing magnetic particles 21 in the resistor layer 2, wherein the magnetic particles 21 account for 5-15wt% of the resistor layer 2, the magnetic loss mechanism (such as eddy current loss and natural resonance) of the magnetic particles 21 is utilized to improve the high-frequency interference suppression capability, effectively reduce the parasitic inductance and capacitance generated by the resistor layer at high frequencies, and ensure the reliability of signal transmission.

[0046] On the other hand, by utilizing the Curie temperature characteristics of the magnetic particles 21 and realizing adaptive adjustment of the resistance value through the magnetocaloric effect, the resistance drift in a high temperature environment can be effectively compensated, thereby suppressing temperature drift and ensuring the reliability of signal transmission.

[0047] In order to demonstrate the beneficial effects of a composite metal foil and a metal-clad laminate provided by the embodiments of the present invention, several embodiments and comparative examples are described below.

[0048] Example 1:

[0049] A composite metal foil includes a base layer 1 and a resistor layer 2. The resistor layer 2 is stacked on one side of the base layer 1. The resistor layer 2 includes magnetic particles 21. The magnetic particles 21 account for 5wt% of the resistor layer 2. The particle size of the magnetic particles 21 is 10nm, and the particle size range of the magnetic particles 21 is 10%.

[0050] Example 2:

[0051] The composite metal foil structure of this embodiment is the same as that of embodiment 1, except that the magnetic particles 21 account for 8 wt % of the resistance layer 2 .

[0052] Example 3:

[0053] The composite metal foil structure of this embodiment is the same as that of embodiment 1, except that the magnetic particles 21 account for 10 wt % of the resistance layer 2 .

[0054] Example 4:

[0055] The composite metal foil structure of this embodiment is the same as that of embodiment 1, except that the magnetic particles 21 account for 15 wt % of the resistance layer 2 .

[0056] Example 5:

[0057] The composite metal foil structure of this embodiment is the same as that of embodiment 1, except that the particle size of the magnetic particles 21 is 20 nm.

[0058] Example 6:

[0059] The composite metal foil structure of this embodiment is the same as that of embodiment 1, except that the particle size of the magnetic particles 21 is 40 nm.

[0060] Example 7:

[0061] The composite metal foil structure of this embodiment is the same as that of embodiment 1, except that the particle size of the magnetic particles 21 is 50 nm.

[0062] Example 8:

[0063] The composite metal foil structure of this embodiment is the same as that of embodiment 1, except that the particle size difference of the magnetic particles 21 is 8%.

[0064] Example 9:

[0065] The composite metal foil structure of this embodiment is the same as that of embodiment 1, except that the particle size of the magnetic particles 21 has a maximum difference of 5%.

[0066] Example 10:

[0067] The composite metal foil structure of this embodiment is the same as that of embodiment 1, except that the particle size difference of the magnetic particles 21 is 2%.

[0068] Comparative Example 1:

[0069] A composite metal foil comprises a base layer 1 and a resistance layer 2. The resistance layer 2 is stacked on one side of the base layer 1 and does not contain magnetic particles.

[0070] Comparative Example 2:

[0071] The structure of the composite metal foil in this comparative example is the same as that in Example 1, except that the magnetic particles 21 account for 2 wt % in the resistance layer 2 .

[0072] Comparative Example 3:

[0073] The structure of the composite metal foil in this comparative example is the same as that in Example 1, except that the magnetic particles 21 account for 30 wt % in the resistance layer 2 .

[0074] Performance testing:

[0075] Signal integrity testing of composite metal foil

[0076] Signal integrity testing was conducted on the composite metal foils of Examples 1-10 and Comparative Examples 1-3. The composite metal foils to be tested were laminated onto a substrate (pressing stage: lamination temperature 220°C, duration 2 hours, pressure 25 kg). Lamination, exposure, and development were performed to produce circuits with a line width and line spacing of 50 / 50 μm. Signal attenuation was measured using a screen analyzer. The test data is shown in Table 1.

[0077] As shown in Table 1 below, the signal attenuation of the composite metal foils of Examples 1 to 10 and Comparative Examples 1 to 3 are shown.

[0078] Table 1. Signal attenuation of the composite metal foils of Examples 1-10 and Comparative Examples 1-3

[0079]

[0080] It can be seen that by applying the composite metal foil of this embodiment, the parasitic inductance and capacitance generated by the resistance layer at high frequencies can be effectively improved, thereby ensuring the reliability of signal transmission.

[0081] In summary, by setting a resistor layer 2 on the base layer 1 and setting magnetic particles 21 in the resistor layer 2, the magnetic particles 21 account for 5-15wt% (5wt%, 8wt%, 10wt% or 15wt%) in the resistor layer 2, and utilizing the magnetic loss mechanism of the magnetic particles 21 (such as eddy current loss and natural resonance), the high-frequency interference suppression capability is improved, the parasitic inductance and capacitance generated by the resistor layer at high frequencies are effectively reduced, and the reliability of signal transmission is ensured.

[0082] On the other hand, by utilizing the Curie temperature characteristics of the magnetic particles 21 and realizing adaptive adjustment of the resistance value through the magnetocaloric effect, the resistance drift in a high temperature environment can be effectively compensated, thereby suppressing temperature drift and ensuring the reliability of signal transmission.

[0083] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A composite metal foil, characterized in that: The method comprises a base layer and a resistance layer, wherein the resistance layer is stacked on one side of the base layer, and the resistance layer comprises magnetic particles, and the magnetic particles account for 5-15wt% of the resistance layer.

2. The composite metal foil according to claim 1, characterized in that The magnetic particles include at least one of NiFe2O4 or Fe3O4.

3. The composite metal foil according to claim 1, characterized in that The particle size of the magnetic particles is 10-50 nm.

4. The composite metal foil according to claim 1, characterized in that The particle size range of the magnetic particles is less than or equal to 10%.

5. The composite metal foil according to claim 1, characterized in that The resistance temperature coefficient of the resistance layer is less than or equal to 50 ppm / °C.

6. The composite metal foil according to claim 1, characterized in that The square resistance uniformity of the resistance layer is less than or equal to 10%.

7. The composite metal foil according to claim 1, characterized in that The resistance layer includes at least one element of Ni, Co, Mo, Cr, Mg, Fe, Sn, Ti, Sn, and C, or the resistance layer includes at least one element of Ni, Co, Mo, Cr, Mg, Fe, Sn, Ti, Sn, and C and at least one element of P, Si, O, and N.

8. The composite metal foil according to claim 1, characterized in that The thickness of the base layer is 5 μm to 50 μm.

9. The metal foil according to any one of claims 1 to 8, characterized in that: The anti-oxidation layer is stacked on a side of the base layer away from the resistance layer.

10. A metal-clad laminate, characterized in that: The metal-clad laminate comprises the composite metal foil according to any one of claims 1 to 9.

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