Composite metal foil and circuit board

Abstract

The application discloses a composite metal foil and a circuit board. The composite metal foil comprises a dielectric layer, an adjusting layer, a first resistance layer and a first conductive layer. The adjusting layer is arranged on one side of the dielectric layer. The first resistance layer is formed on the side of the adjusting layer away from the dielectric layer. At least part of the side of the adjusting layer away from the dielectric layer is provided with a first protruding structure, so that the first resistance layer is provided with a second protruding structure on at least part of the side close to the adjusting layer and the side away from the adjusting layer. The first conductive layer is formed on the side of the first resistance layer away from the adjusting layer. The existence of the second protruding structure increases the cross-sectional area of the first resistance layer, improves the current-carrying capacity of the first resistance layer, and further improves the ESD performance of the first resistance layer and the anti-static breakdown performance of the embedded resistance. In addition, by changing the first protruding structure of the adjusting layer, the morphology and roughness of the first resistance layer can be adjusted, and the product performance of the embedded resistance can be accurately adjusted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite metal foil, and particularly to a composite metal foil and a circuit board. BACKGROUND

[0002] With the rapid development of wireless communication and electronic devices, electronic devices evolve towards precision, miniaturization and lightness, and therefore, the size of components inside electronic devices is required to develop towards miniaturization and lightness as much as possible.

[0003] Resistive elements inside electronic devices gradually develop towards lightness from the previous pin-plugged resistors, to chip resistors, to embedded resistors. The preparation process of embedded resistors is roughly as follows: a composite metal foil is attached to a circuit board, and an embedded resistor is etched through an etching process.

[0004] The application terminal electronic product has a plurality of embedded resistors integrated on the circuit board inside the electronic product, and the circuit is quite sensitive to electrostatic high voltage. When a person or object with static electricity contacts the embedded resistors, static discharge occurs, and when the electrostatic high voltage impacts the circuit, the embedded resistors are easily broken down by the electrostatic high voltage, thereby causing the embedded resistors to fail. SUMMARY

[0005] An object of the present application is to provide a composite metal foil, which can improve the current-carrying capacity of the first resistive layer, thereby improving the ESD (Electro-Static Discharge) performance of the first resistive layer, and further improving the anti-static breakdown performance of the embedded resistor.

[0006] Another object of the present application is to provide a circuit board comprising the composite metal foil provided by the present application.

[0007] To achieve the above object, the present application adopts the following technical solutions.

[0008] In a first aspect, the present application provides a composite metal foil, comprising: a dielectric layer, an adjusting layer, a first resistive layer, and a first conductive layer.

[0009] The adjusting layer is arranged on one side of the dielectric layer.

[0010] The first resistive layer is formed on the side of the adjusting layer away from the dielectric layer.

[0011] At least part of the side of the adjusting layer away from the dielectric layer is provided with a first protruding structure, so that at least part of the side of the first resistive layer close to the adjusting layer and the side of the first resistive layer away from the adjusting layer forms a second protruding structure.

[0012] The first conductive layer is formed on a side of the first resistive layer away from the adjustment layer.

[0013] Optionally, the roughness Rz of the first resistive layer on the side close to the adjustment layer and the side away from the adjustment layer is in the range of 0.1 μm-30 μm.

[0014] Optionally, the roughness Sdr of the first resistive layer on the side close to the adjustment layer and the side away from the adjustment layer is greater than or equal to 0.5%.

[0015] Optionally, the side of the adjustment layer away from the medium layer is provided with first protruding structures on the whole area, so that the first resistive layer on the side close to the adjustment layer and the side away from the adjustment layer forms second protruding structures on the whole area.

[0016] Optionally, the side of the adjustment layer away from the medium layer is provided with a plurality of continuous first protruding structures on at least part of the area, so that the first resistive layer on the side close to the adjustment layer and the side away from the adjustment layer forms a plurality of continuous second protruding structures on at least part of the area.

[0017] Optionally, the side of the adjustment layer away from the medium layer is provided with a plurality of continuous first protruding structures on the whole area, so that the first resistive layer on the side close to the adjustment layer and the side away from the adjustment layer forms a plurality of continuous second protruding structures on the whole area.

[0018] Optionally, the first resistive layer on the side close to the adjustment layer and the side away from the adjustment layer forms continuous second protruding structures on the whole area, so that the first resistive layer forms a continuous wave structure.

[0019] Optionally, the roughness Rz of the first resistive layer on the side close to the adjustment layer and the side away from the adjustment layer is in the range of 0.1 μm-10 μm, and the roughness Sdr of the first resistive layer on the side close to the adjustment layer and the side away from the adjustment layer is greater than or equal to 20%.

[0020] Optionally, the roughness Rz of the first resistive layer on the side close to the adjustment layer and the side away from the adjustment layer is in the range of 0.1 μm-10 μm, and the roughness Sdr of the first resistive layer on the side close to the adjustment layer and the side away from the adjustment layer is greater than or equal to 50%.

[0021] Optionally, the roughness Rz of the first resistive layer on the side close to the adjusting layer and the side away from the adjusting layer is in the range of 0.1 μm-10 μm, and the roughness Sdr of the first resistive layer on the side close to the adjusting layer and the side away from the adjusting layer is greater than or equal to 200%.

[0022] Optionally, the side of the medium layer away from the adjusting layer is provided with a second resistive layer and a second conductive layer, and the second resistive layer is located between the medium layer and the second conductive layer.

[0023] Optionally, the material of the first resistive layer includes at least one single metal of nickel, chromium, platinum, palladium and titanium, and / or an alloy of at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus and aluminum.

[0024] Optionally, the first resistive layer is a single-layer structure or a structure of at least two layers.

[0025] In a second aspect, the embodiments of the present application further provide a circuit board comprising the composite metal foil provided by the first aspect of the present application.

[0026] The composite metal foil provided by the embodiments of the present application comprises a medium layer, an adjusting layer, a first resistive layer and a first conductive layer, the adjusting layer is arranged on one side of the medium layer; the first resistive layer is formed on the side of the adjusting layer away from the medium layer, at least part of the area of the side of the adjusting layer away from the medium layer is provided with a first protruding structure, so that at least part of the area of the side of the first resistive layer close to the adjusting layer and the side away from the adjusting layer forms a second protruding structure, and the first conductive layer is formed on the side of the first resistive layer away from the adjusting layer. The existence of the second protruding structure increases the cross-sectional area of the first resistive layer, improves the current-carrying capacity of the first resistive layer, and further improves the ESD performance of the first resistive layer, and improves the anti-static breakdown performance of the embedded resistive layer. In addition, by changing the first protruding structure of the adjusting layer, the morphology and roughness of the first resistive layer are adjusted, and the product performance of the embedded resistive layer can be accurately adjusted. BRIEF DESCRIPTION OF DRAWINGS

[0027] The present application will be further described in detail below according to the drawings and embodiments.

[0028] Figure 1A A structure schematic diagram of a composite metal foil provided by the embodiments of the present application;

[0029] Figure 1B A structure schematic diagram of another composite metal foil provided by the embodiments of the present application;

[0030] Figure 2A A structure schematic diagram of another composite metal foil provided by the embodiments of the present application;

[0031] Figure 2BAnother structure schematic diagram of the composite metal foil provided by the embodiment of the present application is shown in the figure.

[0032] Figure 2C Another structure schematic diagram of the composite metal foil provided by the embodiment of the present application is shown in the figure.

[0033] Figure 3 Another structure schematic diagram of the composite metal foil provided by the embodiment of the present application is shown in the figure.

[0034] Figure 4A Another structure schematic diagram of the composite metal foil provided by the embodiment of the present application is shown in the figure.

[0035] Figure 4B Another structure schematic diagram of the composite metal foil provided by the embodiment of the present application is shown in the figure.

[0036] Figure 5A A flow chart of the preparation method of the composite metal foil provided by the embodiment of the present application is shown in the figure.

[0037] Figure 5B A schematic diagram of forming the adjusting layer on the medium layer provided by the embodiment of the present application is shown in the figure.

[0038] Figure 5C A schematic diagram of forming the first protruding structure on the side of the adjusting layer away from the medium layer provided by the embodiment of the present application is shown in the figure.

[0039] Figure 5D A schematic diagram of forming the first resistance layer on the adjusting layer provided by the embodiment of the present application is shown in the figure.

[0040] Figure 5E A schematic diagram of forming the first conductive layer on the first resistance layer provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0041] In order to make the technical problems solved by the present application, the technical solutions adopted and the technical effects reached more clear, the technical solutions of the embodiments of the present application will be further described in detail below with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the person skilled in the art without making any creative effort are within the protection scope of the present application.

[0042] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrated; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0043] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0044] Figure 1A A structure diagram of a composite metal foil provided for an embodiment of the present application is shown in the figure, Figure 1B Another structure diagram of a composite metal foil provided for an embodiment of the present application is shown in the figure, Figure 1A And Figure 1B As shown in the figure, in the embodiment, the composite metal foil includes a dielectric layer 110, an adjusting layer 120, a first resistance layer 130 and a first conductive layer 140.

[0045] Specifically, the dielectric layer 110 can be an insulating base layer for carrying the adjusting layer 120. For example, the material of the dielectric layer 110 can be polyimide or resin with certain flexibility and buffering effect.

[0046] The adjusting layer 120 can be an insulating material, which can be the same as or different from the material of the dielectric layer 110, and the present application does not limit it here.

[0047] The first resistance layer 130 is a key functional layer of the composite metal foil, and is used to realize the resistance function of the composite metal foil. Generally, the first resistance layer 130 can be made of different materials according to different functional requirements, and thus has different resistance characteristics. For example, the material of the first resistance layer 130 can include any one of nickel, chromium, platinum, palladium, titanium, and / or an alloy including at least two of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. For example, the first resistance layer 130 can be made of a nickel-chromium alloy (NiCr) or a nickel-phosphorus alloy (NiP) having a low resistivity, or a chromium-silicon alloy (CrSi) having a high resistivity, which is not limited in the embodiments of the present application. The first resistance layer 130 is a precursor of the first resistance layer in the embedded resistance, or in other words, the first resistance layer in the embedded resistance is obtained by removing part of the first resistance layer 130 through etching or other processes. The thickness of the first resistance layer 130 ranges from 0.01 μm to 0.5 μm. It should be noted that the high resistivity and the low resistivity in the embodiments of the present application are for the first resistance layer itself, and not for the first conductive layer.

[0048] In some embodiments of the present application, the first resistance layer 130 has a single-layer structure or an at least two-layer structure. For example, the single-layer structure can be made of any one of nickel, chromium, platinum, palladium, and titanium, or an alloy including at least two of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. Any one of the at least two layers can be made of any one of nickel, chromium, platinum, palladium, and titanium, or an alloy including at least two of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum.

[0049] The first conductive layer 140 has good conductive performance, and the material of the metal layer can be gold, silver, copper, or aluminum, or an alloy including at least two of them. In other embodiments of the present application, the first conductive layer 140 can also be a non-metal layer having good conductive performance, and the material of the first conductive layer is not limited in the embodiments of the present application as long as it has good conductive performance. The thickness of the first conductive layer 140 ranges from 3 μm to 18 μm.

[0050] The adjustment layer 120 is formed on one side of the medium layer 110, and at least part of the area on the side of the adjustment layer 120 away from the medium layer 110 is provided with the first protruding structure 121. The first protruding structure 121 makes at least part of the area on the side of the adjustment layer 120 away from the medium layer 110 have a rough surface. In the embodiments of the present application, the shape of the first protruding structure 121 can be various according to actual requirements, and can be a regular or irregular three-dimensional geometric shape, which is not limited in the embodiments of the present application. In some examples, the first protruding structure makes the adjustment layer have a continuous undulating surface, and forms a relatively regular sine line shape, or the shape of the first protruding structure is one or more of an angular shape, an inverted conical shape, a granular shape, a dendritic shape, a columnar shape, a block shape, and an arc shape.

[0051] The first resistance layer 130 is formed on the side of the adjustment layer 120 away from the dielectric layer 110. In one embodiment of the present application, the first resistance layer 130 can be formed on the side of the adjustment layer 120 away from the dielectric layer 110 by physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating, and hybrid plating. Since the first protruding structure 121 is arranged on at least part of the side of the adjustment layer 120 away from the dielectric layer 110, the first resistance layer 130 formed on the adjustment layer 120 will have two sides conforming to the second protruding structure 131.

[0052] The first conductive layer 140 can be formed on the side of the first resistance layer 130 away from the adjustment layer 120 by physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating, and hybrid plating.

[0053] The inventor has found that the cross-sectional area of the first resistance layer in the embedded resistor affects the ESD performance. The greater the cross-sectional area of the first resistance layer, the greater the current-carrying capacity of the first resistance layer, and the better the ESD performance and the better the anti-static breakdown performance. In order to improve the ESD performance of the embedded resistor, the cross-sectional area of the first resistance layer can be increased.

[0054] The second protruding structure 131 is formed on both sides of the first resistance layer 130, so that the first resistance layer 130 has a rough surface. The presence of the second protruding structure 131 increases the cross-sectional area of the first resistance layer 130, improves the current-carrying capacity of the first resistance layer 130, and further improves the ESD performance of the first resistance layer 130, and further improves the anti-static breakdown performance of the embedded resistor. In addition, the morphology and roughness of the first resistance layer 130 can be adjusted by changing the first protruding structure 121 of the adjustment layer 120, and the product performance of the embedded resistor can be accurately adjusted.

[0055] The composite metal foil provided by the embodiment of the present application includes a dielectric layer, an adjustment layer, a first resistance layer, and a first conductive layer. The adjustment layer is arranged on one side of the dielectric layer. The first resistance layer is formed on the side of the adjustment layer away from the dielectric layer. At least part of the side of the adjustment layer away from the dielectric layer is provided with a first protruding structure, so that at least part of the side of the first resistance layer close to the adjustment layer and the side of the first resistance layer away from the adjustment layer forms a second protruding structure. The first conductive layer is formed on the side of the first resistance layer away from the adjustment layer. The presence of the second protruding structure increases the cross-sectional area of the first resistance layer, improves the current-carrying capacity of the first resistance layer, and further improves the ESD performance of the first resistance layer, and further improves the anti-static breakdown performance of the embedded resistor. In addition, the morphology and roughness of the first resistance layer can be adjusted by changing the first protruding structure of the adjustment layer, and the product performance of the embedded resistor can be accurately adjusted.

[0056] In some embodiments of the present application, the second protruding structure 131 makes the roughness Rz of at least part of the area (the area provided with the protruding structure) on both sides of the first resistance layer 130 range from greater than or equal to 0.1 μm, and the roughness Sdr range from greater than or equal to 0.5%. The roughness Rz and the roughness Sdr are used to characterize the microscopic unevenness of the surface of the first resistance layer 130. Specifically, the average of the five largest profile peak heights in the sampling length is usually taken as the roughness Rz. The roughness Sdr is the increase in the area of the defined area (surface area) relative to the area of the defined area, wherein the roughness Sdr of a completely flat surface is zero. It should be noted that in the embodiments of the present application, the roughness Rz on both sides of the first resistance layer 130 can be the same or different, and the roughness Sdr on both sides of the first resistance layer 130 can be the same or different, which is not limited in the embodiments of the present application. It should be noted that in the embodiments and subsequent embodiments, the test standard of the roughness is ISO25178 standard.

[0057] Further, in some embodiments of the present application, in order to further improve the ESD performance of the first resistance layer, the roughness Rz on both sides of the first resistance layer 130 ranges from 0.1 μm to 30 μm, including 0.1 μm and 30 μm, and the roughness Rz on both sides of the first resistance layer 130 can also be 1 μm, 5 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, etc. The roughness Sdr ranges from 0.5% to 8000%, including 0.5% and 8000%, and the roughness Sdr can also be 1%, 5%, 12%, 20%, 50%, 80%, 100%, 200%, 500%, 800%, 1500%, 2000%, 2500%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 7500%, etc.

[0058] Table 1 is the test result of the ESD test on the first resistance layer with different roughness Rz. The test method is as follows: under the condition that other conditions are constant, a forward test static voltage is applied to the first resistance layer with a certain roughness, applied for three times, and the interval time is 10 seconds each time, then a reverse test static voltage is applied to the first resistance layer, applied for three times, and the interval time is 10 seconds each time. The test static voltage is gradually increased, and the test static voltage that breaks down the first resistance layer is taken as the ESD release voltage of the first resistance layer.

[0059] Table 1

[0060] Rz (pm) Static discharge resistance voltage (KV) 0.1 0.51 1 1.22 2 1.57 4 2.25 6 3.15 10 3.49 30 4.1

[0061] As shown in Table 1, different roughness Rz has different ESD release voltage resistance, that is, by setting the protruding structure on at least part of the area on the side of the first resistive layer away from the first conductive layer, adjusting the roughness Rz of the first resistive layer, the ESD release voltage resistance of the first resistive layer can be improved.

[0062] Table 2 is the test result of the first resistive layer with different roughness Sdr for ESD test, and the test method is the same as before.

[0063] Table 2

[0064]

[0065]

[0066] As shown in Table 2, different roughness Sdr has different ESD release voltage resistance, that is, by setting the protruding structure on at least part of the area on the side of the first resistive layer away from the first conductive layer, adjusting the roughness Sdr of the first resistive layer, the ESD release voltage resistance of the first resistive layer can be improved.

[0067] In the embodiment of the present application, the shape of the second protruding structure 121 can have diversity according to actual needs, which can be regular or irregular three-dimensional geometric shape, for example, the shape of the second protruding structure 121 can be one or more of sharp angle, inverted cone, granular, dendritic, columnar, block, arc, and the like, which are not limited in the embodiment of the present application.

[0068] In order to further improve the ESD performance (i.e. ESD release voltage performance) of the first resistive layer 130, the second protruding structure 131 arranged on at least part of the area on both sides of the first resistive layer 130 is arranged continuously. For example, as shown in Figure 1A , the shape of the second protruding structure 131 is dendritic, and the second protruding structure 131 is continuously distributed on at least part of the area on the first resistive layer 130; or as shown in Figure 1B , the shape of the second protruding structure 131 is arc-shaped, and the second protruding structure 131 is continuously distributed on at least part of the area on the first resistive layer 130 to form a structure similar to "sine curve" on both sides of the first resistive layer 130. In addition, in other embodiments of the present application, the second protruding structure can include a continuous undulating surface formed on both sides of the first resistive layer, and a plurality of convex portions formed on the undulating surface, which are not limited in the embodiment of the present application. In addition, in some other embodiments of the present application, the second protruding structure can also be discontinuously distributed on at least part of the area on both sides of the first resistive layer, which are not limited in the embodiment of the present application.

[0069] In some embodiments of the present application, the material of the medium layer 110 and the adjustment layer 120 can be resin glue, polyimide (PI), modified polyimide, glass cloth, glass cloth composite, paper substrate, composite substrate, HDI board, modified epoxy resin, modified acrylic resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc., which are used to protect the first resistance layer 130 and avoid the first resistance layer 130 from being damaged by external force.

[0070] In some embodiments of the present application, at least part of the area of the adjustment layer 120 is provided with fillers, so that at least part of the area of the side of the adjustment layer 120 away from the medium layer 110 forms a first protruding structure 121. By adjusting the type and size of the adjustment material, the side of the adjustment layer 120 away from the medium layer 110 has different roughness, so as to adjust the roughness of the first resistance layer 130.

[0071] Figure 2A Another structure diagram of a composite metal foil provided by an embodiment of the present application is shown in Figure 2B Another structure diagram of a composite metal foil provided by an embodiment of the present application is shown in Figure 2C Another structure diagram of a composite metal foil provided by an embodiment of the present application is shown in Figure 2A 、 Figure 2B and Figure 2C As shown in the embodiments, the composite metal foil includes a medium layer 210, an adjustment layer 220, a first resistance layer 230 and a first conductive layer 240.

[0072] Specifically, the medium layer 210 can be an insulating base layer for carrying the adjustment layer 220. The adjustment layer 220 can be an insulating material, which can be the same as or different from the medium layer 210. The first resistance layer 230 is a key functional layer of the composite metal foil, which is used to realize the resistance function of the composite metal foil. The material of the first resistance layer 230 can include at least one single metal of nickel, chromium, platinum, palladium and titanium, and / or an alloy including at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus and aluminum. For example, chromium nickel (NiCr) or nickel phosphorus (NiP) with low resistivity, or chromium silicon alloy (CrSi) with high resistivity. In a specific embodiment of the present application, the material of the first resistance layer 230 is chromium nickel. The first conductive layer 240 has good conductivity, and the material of the metal layer can be gold, silver, copper or aluminum, or an alloy of at least two of them.

[0073] At least part of the area of the side of the adjustment layer away from the medium layer is provided with a first protruding structure, for example, Figure 2A 、 Figure 2B and Figure 2CAs shown, the first protruding structure 221 is arranged on the whole area of the side of the adjusting layer 220 close to the first resistance layer 230. Since the first resistance layer 230 is sequentially formed on the side of the adjusting layer 220 provided with the first protruding structure 221, the whole area of the two sides of the formed first resistance layer 230 conforms to the formation of the second protruding structure 231. Since the second protruding structure 231 is arranged on the whole area of the two sides of the first resistance layer 230, the cross-sectional area of the first resistance layer 230 is further increased, and the anti-static breakdown capability of the embedded resistance is improved.

[0074] Specifically, the roughness Rz of the two sides of the first resistance layer 230 is greater than or equal to 0.1 μm, and the roughness Sdr is greater than or equal to 0.5%. It should be noted that in the embodiment of the present application, the roughness Rz of the two sides of the first resistance layer 230 can be the same or different, and the roughness Sdr of the two sides of the first resistance layer 230 can be the same or different, which is not limited in the embodiment of the present application. Preferably, the roughness Rz of the two sides of the first resistance layer 230 is 0.1 μm-30 μm, including 0.1 μm and 30 μm, and the roughness Rz of the two sides of the first resistance layer 230 can also be 1 μm, 5 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, etc. The roughness Sdr is 0.5%-8000%, including 0.5% and 8000%, and the roughness Sdr can also be 1%, 5%, 12%, 20%, 50%, 80%, 100%, 200%, 500%, 800%, 1500%, 2000%, 2500%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 7500%, etc.

[0075] In the embodiment of the present application, the shape of the second protruding structure can be various according to actual needs, which can be regular or irregular three-dimensional geometric shape, which is not limited in the embodiment of the present application. In some examples, the second protruding structure can form a continuous undulating surface on the two sides of the first resistance layer, or can form a relatively regular "sine line" shape on the two sides of the first resistance layer, or the shape of the protruding structure can be one or more of sharp angle, inverted cone, granular, dendritic, columnar, block, arc, etc.

[0076] In the embodiment of the present application, as shown in FIG. 2, the second protruding structure 231 is arranged on the whole area of the two sides of the first resistance layer 230. Figure 2CAs shown, to further improve the ESD resistance of the first resistance layer 230, the second protruding structures 231 arranged on the whole area on both sides of the first resistance layer 230 are arranged continuously, that is, the second protruding structures 231 are arranged continuously on both sides of the first resistance layer 230, so as to further increase the cross-sectional area of the first resistance layer 230 and improve the ESD resistance of the first resistance layer 230, thereby improving the anti-static breakdown capability of the embedded resistance.

[0077] Further, if the roughness height parameter Rz of the second protruding structures 231 is set too high, the second protruding structures 231 are prone to be broken under the action of external force in application, thereby affecting the ESD resistance of the first resistance layer 230. Therefore, the roughness Rz of the first resistance layer 230 is set to be in the range of 0.1 μm-10 μm, and the roughness Sdr of the first resistance layer 230 is set to be greater than or equal to 20%. By limiting the roughness height parameter Rz of the first resistance layer 230 to be in the range of 0.1 μm-10 μm and the increase parameter Sdr of the surface area relative to the defined area to be greater than or equal to 20%, the second protruding structures 231 arranged continuously and closely on the whole area on both sides of the first resistance layer 230 (the protruding structures arranged continuously and closely on the whole area are similar to a "fluff" structure) are obtained within a certain height range of the second protruding structures 231, so that the first resistance layer 230 with a larger cross section is obtained under the condition that the roughness height parameter Rz is certain, that is, the second protruding structures 231 are ensured not to be broken under the action of external force, thereby improving the ESD resistance of the first resistance layer 230 and effectively ensuring that the embedded resistance has a stronger anti-static breakdown capability.

[0078] Preferably, the roughness Rz of the first resistance layer 230 is in the range of 0.1 μm-10 μm, and the roughness Sdr of the first resistance layer 230 is greater than or equal to 50%. By limiting the roughness height parameter Rz of the first resistance layer 230 to be in the range of 0.1 μm-10 μm and the increase parameter Sdr of the surface area relative to the defined area to be greater than or equal to 50%, the second protruding structures 231 arranged continuously and more closely on the whole area on both sides of the first resistance layer 230 are obtained within a certain height range of the second protruding structures 231, that is, the protruding structures arranged more closely than the roughness Sdr greater than or equal to 20% are obtained, so as to further increase the cross section of the first resistance layer and further improve the ESD resistance of the first resistance layer, thereby effectively ensuring that the embedded resistance has a stronger anti-static breakdown capability.

[0079] More preferably, the roughness Rz of the first resistance layer 230 ranges from 0.1 μm to 10 μm, and the roughness Sdr of the first resistance layer 230 ranges from greater than or equal to 200%, so as to further increase the cross section of the first resistance layer, and further improve the ESD performance of the first resistance layer, and effectively ensure that the embedded resistance has excellent anti-static breakdown capability.

[0080] In some embodiments of the present application, the material of the medium layer 210 and the adjustment layer 220 can be resin glue, polyimide (PI), modified polyimide, glass cloth, glass cloth composite material, paper substrate, composite substrate, HDI plate material, modified epoxy resin, modified acrylic resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc., which are used to protect the first resistance layer 230 and avoid the first resistance layer 230 from being damaged by external force.

[0081] In some embodiments of the present application, the adjustment layer 220 is provided with fillers in the entire area, so that at least part of the area on the side of the adjustment layer 220 away from the medium layer 210 is formed with the first protruding structure 221. By adjusting the type and size of the fillers, the side of the adjustment layer 220 away from the medium layer 210 has different roughness, so as to adjust the roughness of the first resistance layer 230.

[0082] Figure 3 Another structure diagram of the composite metal foil provided by the embodiments of the present application is shown in FIG. 3. Figure 3 As shown in FIG. 3, the composite metal foil includes a medium layer 310, an adjustment layer 320, a first resistance layer 330, and a first conductive layer 340.

[0083] Specifically, the medium layer 310 can be an insulating base layer for carrying the adjustment layer 320. The adjustment layer 320 can be an insulating material, which can be the same as or different from the medium layer 310. The first resistance layer 330 is a key functional layer of the composite metal foil, which is used to realize the resistance function of the composite metal foil. The material of the first resistance layer 330 can include at least one single metal of nickel, chromium, platinum, palladium, and titanium, and / or an alloy including at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. For example, chromium nickel (NiCr) or nickel phosphorus (NiP) with low resistivity, or chromium silicon alloy (CrSi) with high resistivity. In a specific embodiment of the present application, the material of the first resistance layer 330 is chromium nickel. The first conductive layer 340 has good conductivity, and the material of the metal layer can be gold, silver, copper, or aluminum, or an alloy of at least two of them.

[0084] The side of the adjustment layer away from the medium layer is provided with the first protruding structure in at least part of the area, for example, Figure 3As shown, the first protruding structure 321 is arranged on the whole area of the side of the adjustment layer 320 close to the first resistance layer 330, and the plurality of first protruding structures 321 are continuous, forming a wavy surface. Since the first resistance layer 330 is sequentially formed on the side of the adjustment layer 320 provided with the first protruding structure 321, the whole area of the two sides of the first resistance layer 330 is formed to conform to the second protruding structure 331, and the second protruding structure 331 makes the first resistance layer 330 form a continuous wavy structure.

[0085] Specifically, the roughness Rz of the two sides of the first resistance layer 330 ranges from greater than or equal to 0.1 μm, and the roughness Sdr ranges from greater than or equal to 0.5%. It should be noted that in the embodiments of the present application, the roughness Rz of the two sides of the first resistance layer 330 can be the same or different, and the roughness Sdr of the two sides of the first resistance layer 330 can be the same or different, which is not limited in the embodiments of the present application. Preferably, the roughness Rz of the two sides of the first resistance layer 330 ranges from 0.1 μm to 30 μm, including 0.1 μm and 30 μm, and the roughness Rz of the two sides of the first resistance layer 330 can also be 1 μm, 5 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, etc. The roughness Sdr ranges from 0.5% to 8000%, including 0.5% and 8000%, and the roughness Sdr can also be 1%, 5%, 12%, 20%, 50%, 80%, 100%, 200%, 500%, 800%, 1500%, 2000%, 2500%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 7500%, etc.

[0086] In some embodiments of the present application, the material of the medium layer 310 and the adjustment layer 320 can be resin glue, polyimide (PI), modified polyimide, glass cloth, glass cloth composite material, paper substrate, composite substrate, HDI plate material, modified epoxy resin, modified acrylic resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc., which is used to protect the first resistance layer 330 and avoid the first resistance layer 330 from being damaged by external force.

[0087] In some embodiments of the present application, the adjustment layer 320 is provided with fillers on the whole area, so that at least part of the area of the side of the adjustment layer 320 away from the medium layer 310 is formed with the first protruding structure 321. By adjusting the type and size of the fillers, the side of the adjustment layer 320 away from the medium layer 310 has different roughness, so as to adjust the roughness of the first resistance layer 330.

[0088] Furthermore, a second resistive layer and a second conductive layer are disposed on the side of the dielectric layer away from the first resistive layer, with the second resistive layer located between the dielectric layer and the second conductive layer. The materials and uses of the second resistive layer and the first resistive layer can be the same or different; similarly, the materials and uses of the second conductive layer and the first conductive layer can be the same or different. In addition, the structure and parameters of the second resistive layer can be the same as those of the first resistive layer, and the structure and parameters of the second conductive layer can also be the same as those of the first conductive layer; these will not be elaborated further here. Furthermore, in some embodiments of the present invention, an adjustment layer can also be disposed between the dielectric layer and the second resistive layer. This adjustment layer can have the same structure, material, and parameters as the adjustment layer between the dielectric layer and the first resistive layer, and has the same function.

[0089] Figure 4A This is a schematic diagram of another composite metal foil provided in an embodiment of the present invention. Figure 4B A schematic diagram of another composite metal foil provided in an embodiment of the present invention is shown below. Figure 4A and Figure 4B As shown, in this embodiment, the composite metal foil includes a dielectric layer 410, an adjustment layer 420, a first resistive layer 430, a first conductive layer 440, a second resistive layer 450, and a second conductive layer 460.

[0090] An adjustment layer 420 is formed on one side of the dielectric layer 410, a first resistive layer 430 is formed on the side of the adjustment layer 420 away from the dielectric layer 410, and a first conductive layer 440 is formed on the side of the first resistive layer 430 away from the adjustment layer 420. A first protrusion structure 421 is provided in the entire area of ​​the side of the adjustment layer 420 away from the dielectric layer, giving the adjustment layer 420 an uneven surface, and second protrusion structures 431 are formed on both sides of the formed first resistive layer 430 accordingly. The materials of the first conductive layer, the first resistive layer, the adjustment layer, and the dielectric layer, the shape of the second protrusion structure, and the roughness of both sides of the first resistive layer have been described in detail in the foregoing embodiments, and will not be repeated here.

[0091] The second resistive layer 450 is disposed on the side of the dielectric layer 410 away from the regulating layer 420, and the second conductive layer 460 is disposed on the side of the second resistive layer 450 away from the dielectric layer 410. In a specific embodiment of the present invention, the second resistive layer 450 and the first resistive layer 430 are made of the same material and have the same purpose; similarly, the second conductive layer 460 and the first conductive layer 440 are made of the same material and have the same purpose.

[0092] One or both sides of the second resistive layer 450 can be flat surfaces, or, similar to the first resistive layer 430, at least a portion of which may have raised structures. For example, as... Figure 4A As shown, the second resistive layer 450 has a raised structure on the side away from the dielectric layer 410; for example...Figure 4B As shown, all regions on both sides of the second resistance layer 450 are provided with the protruding structure, which can refer to the protruding structure on the first resistance layer 430 described in the foregoing embodiments of the present application, and the embodiments of the present application will not be described here again.

[0093] Figure 5A A flow chart of a preparation method of a composite metal foil provided by an embodiment of the present application is shown in FIG. 5. Figure 5A As shown, the method comprises the following steps.

[0094] S501, providing a medium layer.

[0095] Specifically, the medium layer can be resin glue, polyimide (PI), modified polyimide, glass cloth, glass cloth composite material, paper substrate, composite substrate, HDI plate, modified epoxy resin, modified acrylic resin, polyethylene terephthalate glycol, polybutylene terephthalate, polyethylene, etc.

[0096] S502, forming an adjustment layer on one side of the medium layer.

[0097] Specifically, the adjustment layer can be an insulating material, which can be the same as or different from the medium layer, and the embodiments of the present application will not be limited here. Exemplarily, the precursor solution of the adjustment layer is coated on one side of the medium layer to obtain the adjustment layer, or the adjustment layer can be directly attached to the medium layer.

[0098] Figure 5B A schematic diagram of forming an adjustment layer on a medium layer provided by an embodiment of the present application is shown in FIG. 5. Figure 5B As shown, the adjustment layer 520 is formed on one side of the medium layer 510.

[0099] S503, forming a first protruding structure on at least part of the region on the side of the adjustment layer away from the medium layer.

[0100] Specifically, the side of the adjustment layer away from the medium layer can be subjected to roughening treatment, which can include but is not limited to physical polishing, chemical corrosion, shot blasting and sand blasting, etc. After the roughening treatment, the first protruding structure is formed on at least part of the region on the side of the adjustment layer away from the medium layer. In addition, the first protruding structure can also be formed on at least part of the region on the side of the adjustment layer away from the medium layer by setting fillers in the adjustment layer.

[0101] In some embodiments of the present application, at least part of the region of the adjustment layer is provided with fillers, so that the first protruding structure is formed on at least part of the region on the side of the adjustment layer away from the medium layer. By adjusting the types and sizes of the fillers, the side of the adjustment layer away from the medium layer has different roughness, so as to adjust the roughness of the first resistance layer.

[0102] Figure 5CA schematic diagram of forming the first protruding structure on the side of the adjustment layer away from the dielectric layer is provided for the embodiments of the present application, as shown in Figure 5C The whole area of the side of the adjustment layer 520 away from the dielectric layer 510 forms the first protruding structure 521. The shape of the first protruding structure 521 can be various according to actual needs, which can be regular or irregular three-dimensional geometric shapes, and the embodiments of the present application are not limited herein. In some examples, the first protruding structure makes the adjustment layer have a continuous undulating surface, forming a more regular sinusoidal shape, or the shape of the first protruding structure is one or more of sharp angle shape, inverted cone shape, granular shape, branch shape, columnar shape, block shape, and arc shape.

[0103] S504, forming a first resistance layer on the side of the adjustment layer away from the dielectric layer.

[0104] Specifically, the first resistance layer can be formed on the side of the adjustment layer away from the dielectric layer by physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating, and hybrid plating. The first resistance layer is a key functional layer of the composite metal foil, which is used to realize the resistance function of the composite metal foil. The material of the first resistance layer can include at least one elemental metal of nickel, chromium, platinum, palladium, and titanium, and / or an alloy including at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. For example, nickel-chromium alloy (NiCr) or nickel-phosphorus alloy (NiP) with low resistivity, or chromium-silicon alloy (CrSi) with high resistivity, and the embodiments of the present application are not limited herein. In some embodiments of the present application, the first resistance layer can be a single-layer structure or at least a two-layer structure. Any layer can be a single metal composed of any one of nickel, chromium, platinum, palladium, and titanium, or an alloy including at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum.

[0105] Figure 5D A schematic diagram of forming the first resistance layer on the adjustment layer is provided for the embodiments of the present application, as shown in Figure 5D The first resistance layer 530 is formed on the side of the adjustment layer 520 away from the dielectric layer 510. Due to the formation of the first protruding structure 521 on the adjustment layer 520, the first resistance layer 530 on both sides conforms to form a second protruding structure 531. The shape of the second protruding structure can be various according to actual needs, which can be regular or irregular three-dimensional geometric shapes, and the embodiments of the present application are not limited herein. In some examples, the second protruding structure can form a continuous undulating surface on both sides of the first resistance layer, or form a more regular sinusoidal shape on both sides of the first resistance layer, or the shape of the second protruding structure is one or more of sharp angle shape, inverted cone shape, granular shape, branch shape, columnar shape, block shape, and arc shape, or the second protruding structure makes the first resistance layer form a continuous wave undulating structure.

[0106] Specifically, the roughness Rz of the two sides of the first resistance layer 530 is greater than or equal to 0.1 μm, and the roughness Sdr is greater than or equal to 0.5%. It should be noted that in the embodiment of the present application, the roughness Rz of the two sides of the first resistance layer 530 can be the same or different, and the roughness Sdr of the two sides of the first resistance layer 530 can be the same or different, which is not limited in the embodiment of the present application. Preferably, the roughness Rz of the two sides of the first resistance layer 520 is 0.1 μm-30 μm, including 0.1 μm and 30 μm, and the roughness Rz of the two sides of the first resistance layer 520 can also be 1 μm, 5 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, etc. The roughness Sdr is 0.5%-8000%, including 0.5% and 8000%, and the roughness Sdr can also be 1%, 5%, 12%, 20%, 50%, 80%, 100%, 200%, 500%, 800%, 1500%, 2000%, 2500%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 7500%, etc.

[0107] Since the morphology and roughness of the two sides of the first resistance layer are determined by the adjusting layer, the shape and size of the first protruding structure on the adjusting layer can be changed to adjust the morphology and roughness of the two sides of the first resistance layer, thereby realizing accurate adjustment of the product performance of the embedded resistance.

[0108] S505, forming a first conductive layer on the side of the first resistance layer away from the adjusting layer.

[0109] Specifically, the first conductive layer can be formed on the side of the first resistance layer away from the adjusting layer by physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating and hybrid plating. The first conductive layer has good conductivity, and the material of the metal layer can be gold, silver, copper or aluminum, or an alloy of at least two of them.

[0110] Figure 5E The schematic diagram provided by the embodiment of the present application for forming a first conductive layer on a first resistance layer is shown in Figure 5E The first conductive layer 540 is formed on the side of the first resistance layer 530 away from the adjusting layer 520.

[0111] Further, a second resistance layer and a second conductive layer can also be provided on the side of the dielectric layer away from the adjusting layer, and the second resistance layer is located between the dielectric layer and the second conductive layer.

[0112] The preparation method of the composite metal foil provided by the embodiment of the present application comprises: providing a medium layer, forming an adjusting layer on one side of the medium layer, forming a first protruding structure on at least part of the area on the side of the adjusting layer away from the medium layer, forming a first resistance layer on the side of the adjusting layer away from the medium layer, and forming a first conductive layer on the side of the first resistance layer away from the adjusting layer. Through the above method, a second protruding structure is formed on both sides of the first resistance layer. The presence of the second protruding structure increases the cross-sectional area of the first resistance layer, improves the current-carrying capacity of the first resistance layer, and further improves the ESD performance of the first resistance layer, and further improves the anti-static breakdown performance of the embedded resistance.

[0113] The embodiment of the present application also provides a circuit board comprising the composite metal foil provided by any of the above embodiments of the present application.

[0114] The circuit board provided by the embodiment of the present application has corresponding functions and beneficial effects of the composite metal foil provided by the embodiment of the present application.

[0115] In the description herein, it should be understood that the terms "upper", "lower", "left", "right", and the like orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0116] In the description of the present specification, the description referring to the terms "an embodiment", "an example", and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0117] In addition, it should be understood that although the present specification is described in terms of embodiments, each embodiment does not necessarily contain only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that those skilled in the art can understand.

[0118] The technical principles of the present application are described above in conjunction with specific embodiments. These descriptions are only for the purpose of explaining the principles of the present application, and cannot be interpreted in any way as a limitation on the scope of protection of the present application. Based on the explanations here, those skilled in the art do not need to make creative efforts to think of other specific embodiments of the present application, and these embodiments will fall within the scope of protection of the present application.

Claims

1. A composite metal foil for buried resist, characterized by comprising a metal foil having a surface resistance of 0.01 Ω / D or less and a metal foil having a surface resistance of 0.01 Ω / D or more. The application relates to a multilayered structure, which comprises a medium layer, a regulating layer, a first resistance layer and a first conductive layer. The regulating layer is arranged on one side of the medium layer. The first resistance layer is formed on the side of the regulating layer away from the medium layer. At least part of the area on the side of the regulating layer away from the medium layer is provided with a first protruding structure, so that at least part of the area on the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer forms a second protruding structure. The first conductive layer is formed on the side of the first resistance layer away from the regulating layer. The roughness Rz of the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer is in the range of 0.1-30 mu m. The roughness Sdr of the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer is greater than or equal to 0.5%. The whole area on the side of the regulating layer away from the medium layer is provided with the first protruding structure, so that the whole area on the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer forms the second protruding structure.

2. The composite metal foil for embedded resistors according to claim 1, wherein At least part of the area on the side of the regulating layer away from the medium layer is provided with a plurality of continuous first protruding structures, so that at least part of the area on the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer forms a plurality of continuous second protruding structures.

3. The composite metal foil for embedded resistors according to claim 1, wherein The whole area on the side of the regulating layer away from the medium layer is provided with a plurality of continuous first protruding structures, so that the whole area on the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer forms a plurality of continuous second protruding structures.

4. The composite metal foil for embedded resistors according to claim 3, wherein The whole area on the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer forms continuous second protruding structures, so that the first resistance layer forms a continuous wave structure.

5. The composite metal foil for embedded resistors according to claim 3, wherein The roughness Rz of the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer is in the range of 0.1-10 mu m, and the roughness Sdr of the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer is greater than or equal to 20%.

6. The composite metal foil for embedded resistors according to any one of claims 1 to 5, wherein The roughness Rz of the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer is in the range of 0.1-10 mu m, and the roughness Sdr of the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer is greater than or equal to 50%.

7. The composite metal foil for embedded resistors according to any one of claims 1 to 5, wherein The roughness Rz of the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer is in the range of 0.1-10 mu m, and the roughness Sdr of the side of the first resistance layer close to the regulating layer and the side of the first resistance layer away from the regulating layer is greater than or equal to 200%.

8. The composite metal foil for embedded resistors according to any one of claims 1 to 5, wherein The side of the medium layer away from the regulating layer is provided with a second resistance layer and a second conductive layer, and the second resistance layer is arranged between the medium layer and the second conductive layer.

9. The composite metal foil for embedded resistors according to any one of claims 1 to 5, wherein ​ 10. The composite metal foil for embedded resistors according to any one of claims 1 to 5, wherein The material of the first resistance layer comprises at least one single metal of nickel, chromium, platinum, palladium, titanium, and / or an alloy of at least two of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum.

11. The composite metal foil for embedded resistors according to claim 10, wherein The first resistance layer is a single-layer structure or at least a two-layer structure.

12. A wiring board, characterized by The composite metal foil for the embedded resistance comprises the composite metal foil as claimed in any one of claims 1-11.

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