CN114554686A

CN114554686A - Composite metal foil and circuit board

Info

Publication number: CN114554686A
Application number: CN202011307443.7A
Authority: CN
Inventors: 苏陟
Original assignee: Guangzhou Fangbang Electronics Co Ltd
Current assignee: Guangzhou Fangbang Electronics Co Ltd
Priority date: 2020-11-19
Filing date: 2020-11-19
Publication date: 2022-05-27
Also published as: WO2022104996A1

Abstract

The invention discloses a composite metal foil and a circuit board, wherein the composite metal foil comprises: the resistance-adjustable resistor comprises a dielectric layer, an adjusting layer, a first resistance layer and a first conducting layer, wherein the adjusting layer is arranged on one side of the dielectric layer; the first resistance layer is formed on one side, far away from the medium layer, of the adjusting layer, at least partial area of one side, far away from the medium layer, of the adjusting layer is provided with a first protruding structure, so that a second protruding structure is formed on one side, close to the adjusting layer, of the first resistance layer and at least partial area of one side, far away from the adjusting layer, of the first resistance layer, and the first conducting layer is formed on one side, far away from the adjusting layer, of the first resistance layer. Due to the existence of the second protruding structure, the sectional area of the first resistance layer is increased, the current-carrying capacity of the first resistance layer is improved, the ESD resistance of the first resistance layer is further improved, and the antistatic breakdown performance of the embedded resistor is improved. In addition, the appearance and the roughness of the first resistance layer are adjusted by changing the first protruding structure of the adjusting layer, so that the product performance of the embedded resistor can be accurately adjusted.

Description

Composite metal foil and circuit board

Technical Field

The invention relates to the technical field of composite metal foils, in particular to a composite metal foil and a circuit board.

Background

With the rapid development of wireless communication and electronic devices, electronic devices have evolved toward miniaturization, and lightness, and thus, the size of components inside the electronic devices is required to be as miniaturized, as slim as possible.

The resistance element inside the electronic device gradually develops from the previous plug-in resistor with pins, to the chip resistor, and then to the embedded resistor, to be light and thin. The preparation process of the embedded resistor is roughly as follows: and attaching the composite metal foil to the circuit board, and etching the embedded resistor by an etching process.

The embedded resistors are integrated on a circuit board inside an application terminal electronic product, the circuit is sensitive to high static voltage, when people or objects with static electricity contact the embedded resistors, static electricity can be released, and after the static voltage impacts the circuit, the embedded resistors are easily broken down by the high static voltage, so that the embedded resistors fail to function.

Disclosure of Invention

One object of an embodiment of the present invention is to: provided is a composite metal foil, which can improve the current-carrying capacity of a first resistance layer, further improve the ESD (Electro-Static Discharge) resistance of the first resistance layer, and further improve the anti-electrostatic breakdown resistance of an embedded resistor.

Another object of an embodiment of the present invention is to: a circuit board is provided, which comprises the composite metal foil provided by the embodiment of the invention.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, an embodiment of the present invention provides a composite metal foil, including: the resistance adjusting device comprises a dielectric layer, an adjusting layer, a first resistance layer and a first conducting layer;

the adjusting layer is arranged on one side of the medium layer;

the first resistance layer is formed on one side, far away from the dielectric layer, of the adjusting layer;

at least partial region of one side of the adjusting layer far away from the dielectric layer is provided with a first protruding structure, so that at least partial region of one side of the first resistance layer close to the adjusting layer and one side of the first resistance layer far away from the adjusting layer form a second protruding structure;

the first conductive layer is formed on one side of the first resistance layer far away from the adjusting layer.

Optionally, the roughness Rz of the side of the first resistance layer close to the adjusting layer and the side far away from the adjusting layer both range from 0.1 μm to 30 μm.

Optionally, the ranges of the roughness Sdr of the first resistance layer on the side close to the adjusting layer and the side far away from the adjusting layer are both greater than or equal to 0.5%.

Optionally, all areas of one side of the adjusting layer, which is far away from the dielectric layer, are provided with first protruding structures, so that all areas of one side of the first resistance layer, which is close to the adjusting layer, and one side of the first resistance layer, which is far away from the adjusting layer, form second protruding structures.

Optionally, at least a partial region of one side of the adjusting layer, which is far away from the dielectric layer, is provided with a plurality of continuous first protruding structures, so that at least partial regions of one side of the first resistance layer, which is close to the adjusting layer, and one side of the first resistance layer, which is far away from the adjusting layer, form a plurality of continuous second protruding structures.

Optionally, all areas of one side of the adjusting layer, which is far away from the dielectric layer, are provided with a plurality of continuous first protruding structures, so that all areas of one side of the first resistance layer, which is close to the adjusting layer, and one side of the first resistance layer, which is far away from the adjusting layer, form a plurality of continuous second protruding structures.

Optionally, all areas of one side of the first resistance layer close to the adjustment layer and one side of the first resistance layer far from the adjustment layer form a continuous second protrusion structure, so that the first resistance layer forms a continuous wave structure.

Optionally, the roughness Rz of the first resistance layer on the side close to the adjustment layer and the roughness Sdr of the first resistance layer on the side far away from the adjustment layer both range from 0.1 μm to 10 μm, and the roughness Sdr of the first resistance layer on the side close to the adjustment layer and the roughness Sdr of the first resistance layer on the side far away from the adjustment layer both range from 20% or more.

Optionally, the ranges of the roughness Rz of the first resistance layer on the side close to the adjustment layer and the side far away from the adjustment layer are both 0.1 μm to 10 μm, and the ranges of the roughness Sdr of the first resistance layer on the side close to the adjustment layer and the side far away from the adjustment layer are both greater than or equal to 50%.

Optionally, the ranges of the roughness Rz of the first resistance layer on the side close to the adjustment layer and the side far away from the adjustment layer are both 0.1 μm to 10 μm, and the ranges of the roughness Sdr of the first resistance layer on the side close to the adjustment layer and the side far away from the adjustment layer are both greater than or equal to 200%.

Optionally, a second resistance layer and a second conductive layer are disposed on one side of the dielectric layer away from the adjustment layer, and the second resistance layer is located between the dielectric layer and the second conductive layer.

Optionally, the material of the first resistance layer includes at least one simple 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.

Optionally, the first resistive layer is a single-layer structure or at least a two-layer structure.

In a second aspect, an embodiment of the present invention further provides a circuit board, including the composite metal foil provided in the first aspect of the present invention.

The composite metal foil provided by the embodiment of the invention comprises a dielectric layer, an adjusting layer, a first resistance layer and a first conducting layer, wherein the adjusting layer is arranged on one side of the dielectric layer; the first resistance layer is formed on one side, far away from the medium layer, of the adjusting layer, at least partial area of one side, far away from the medium layer, of the adjusting layer is provided with a first protruding structure, so that a second protruding structure is formed on one side, close to the adjusting layer, of the first resistance layer and at least partial area of one side, far away from the adjusting layer, of the first resistance layer, and the first conducting layer is formed on one side, far away from the adjusting layer, of the first resistance layer. Due to the existence of the second protruding structure, the sectional area of the first resistance layer is increased, the current-carrying capacity of the first resistance layer is improved, the ESD resistance of the first resistance layer is further improved, and the antistatic breakdown performance of the embedded resistor is improved. In addition, the appearance and the roughness of the first resistance layer are adjusted by changing the first protruding structure of the adjusting layer, so that the product performance of the embedded resistor can be accurately adjusted.

Drawings

The invention is explained in more detail below with reference to the figures and examples.

Fig. 1A is a schematic structural diagram of a composite metal foil according to an embodiment of the present invention;

fig. 1B is a schematic structural diagram of another composite metal foil provided in an embodiment of the present invention;

fig. 2A is a schematic structural diagram of another composite metal foil provided in an embodiment of the present invention;

FIG. 2B is a schematic structural diagram of another composite metal foil according to an embodiment of the present invention;

FIG. 2C is a schematic structural diagram of another composite metal foil according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of another composite metal foil provided in an embodiment of the present invention;

FIG. 4A is a schematic structural diagram of another composite metal foil provided in an embodiment of the present invention;

FIG. 4B is a schematic structural diagram of another composite metal foil according to an embodiment of the present invention;

FIG. 5A is a flowchart of a method for manufacturing a composite metal foil according to an embodiment of the present invention

FIG. 5B is a schematic diagram of a tuning layer formed on a dielectric layer according to an embodiment of the present invention;

fig. 5C is a schematic view of forming a first protrusion structure on a side of the adjusting layer away from the dielectric layer according to an embodiment of the disclosure;

FIG. 5D is a schematic diagram of a first resistive layer formed on a tuning layer according to an embodiment of the present invention;

fig. 5E is a schematic diagram of forming a first conductive layer on a first resistive layer according to an embodiment of the present invention.

Detailed Description

In order to make the technical problems solved, technical solutions adopted and technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, unless expressly stated or limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, e.g., as meaning permanently connected, removably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means 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 with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature. Furthermore, the terms "first" and "second" are used merely for descriptive purposes and are not intended to have any special meaning.

Fig. 1A is a schematic structural diagram of a composite metal foil according to an embodiment of the present invention, and fig. 1B is a schematic structural diagram of another composite metal foil according to an embodiment of the present invention, as shown in fig. 1A and fig. 1B, in this embodiment, the composite metal foil includes a dielectric layer 110, an adjustment layer 120, a first resistance layer 130, and a first conductive layer 140.

In particular, dielectric layer 110 may be an insulating base layer for carrying conditioning layer 120. Illustratively, the material of dielectric layer 110 may be polyimide or resin, which has some flexibility and cushioning effect.

Adjusting layer 120 may be an insulating material, which may be the same as or different from dielectric layer 110, and embodiments of the present invention are not limited thereto.

The first resistance layer 130 is a key functional layer of the composite metal foil, and is used for realizing 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 may include any one of elementary metals of nickel, chromium, platinum, palladium, and titanium, and/or an alloy including a combination of at least two of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. For example, 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, and the embodiments of the present invention are not limited thereto. The first resistance layer 130 is used as a precursor of the first resistance layer in the embedded resistor, in other words, the first resistance layer in the embedded resistor is obtained by removing a portion of the first resistance layer 130 by etching or the like. 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 invention are for the first resistive layer itself, and not for the first conductive layer.

In some embodiments of the present invention, the first resistive layer 130 is a single layer structure or at least a two-layer structure. Illustratively, the single-layer structure may be a single-layer structure composed of any one metal of nickel, chromium, platinum, palladium and titanium, or may be a single-layer structure composed of an alloy of at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus and aluminum. Any layer in the at least two-layer structure can be a single metal composed of any one of nickel, chromium, platinum, palladium and titanium, and can also be an alloy formed by combining at least two of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus and aluminum.

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

The adjusting layer 120 is formed on one side of the dielectric layer 110, and at least a partial region of one side of the adjusting layer 120 away from the dielectric layer 110 is provided with a first protrusion structure 121. The first protrusion structures 121 provide the adjustment layer 120 with a rough surface in at least a partial region of a side thereof away from the dielectric layer 110. In the embodiment of the present invention, the shape of the first protrusion structure 121 may have a variety according to actual needs, and may be a regular or irregular solid geometric shape, which is not limited herein. In some examples, the first raised structure provides the regulation layer with a continuous undulating surface forming a more regular sinusoidal line shape, or the first raised structure may have one or more of a pointed shape, an inverted conical shape, a granular shape, a dendritic shape, a columnar shape, a block shape, and an arc shape.

First resistance layer 130 is formed on a side of adjusting layer 120 away from dielectric layer 110, and in one embodiment of the present invention, first resistance layer 130 may be formed on a side of adjusting layer 120 away from dielectric layer 110 by physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, and hybrid plating. Since at least partial region of the adjusting layer 120 on the side away from the dielectric layer 110 is provided with the first protrusion structures 121, when the first resistance layer 130 is formed on the adjusting layer 120, the second protrusion structures 131 are formed on both sides of the first resistance layer.

The first conductive layer 140 may be formed on a side of the first resistance layer 130 away from the adjustment layer 120 by physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, hybrid plating, or the like.

The inventors have found that the cross-sectional area of the first resistance layer in the embedded resistor affects the ESD resistance. When the sectional area of the first resistance layer is larger, the current-carrying capacity of the first resistance layer is larger, the ESD performance is better, and the anti-electrostatic breakdown performance is better. In order to improve the ESD performance of the buried resistor, the sectional area of the first resistance layer may be increased.

The embodiment of the invention forms the second protrusion structures 131 on both sides of the first resistance layer 130, so that the first resistance layer 130 has a rough surface. Due to the existence of the second protrusion structure 131, the sectional area of the first resistance layer 130 is increased, the current-carrying capacity of the first resistance layer 130 is increased, and therefore the ESD resistance of the first resistance layer 130 is improved, and the electrostatic breakdown resistance of the embedded resistor is improved. In addition, the first protruding structures 121 of the adjusting layer 120 can be changed to adjust the morphology and roughness of the first resistance layer 130, so as to precisely adjust the product performance of the embedded resistor.

In some embodiments of the present invention, the second convex structures 131 make the range of the roughness Rz of at least partial regions (regions where the convex structures are disposed) on both sides of the first resistance layer 130 be greater than or equal to 0.1 μm, and the range of the roughness Sdr be greater than or equal to 0.5%. The roughness Rz and the roughness Sdr are used to characterize the micro unevenness of the surface of the first resistance layer 130, and specifically, the roughness Rz is generally taken as the sum of the average value of the five maximum profile peak heights and the average value of the five maximum profile valley depths within the sampling length. The roughness Sdr is an extended area (surface area) of the defined region indicates how much an increase is made with respect to the area of the defined region, wherein the roughness Sdr of the completely flat surface is zero. It should be noted that, in the embodiment of the present invention, the roughness Rz of the two sides of the first resistance layer 130 may be the same or different, and the roughness Sdr of the two sides of the first resistance layer 130 may be the same or different, which is not limited herein. In this and subsequent examples, the roughness test standard is ISO25178 standard.

Further, in some embodiments of the present invention, in order to further improve the ESD resistance of the first resistance layer, the roughness Rz of 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 of both sides of the first resistance layer 130 may also take on the values of 1 μm, 5 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, and the like. The roughness Sdr may range from 0.5% to 8000%, including 0.5% and 8000%, and may also take on values of 1%, 5%, 12%, 20%, 50%, 80%, 100%, 200%, 500%, 800%, 1500%, 2000%, 2500%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 7500%, and the like.

Table 1 shows the test results obtained by performing the ESD resistance test on the first resistance layers with different roughness Rz, in the following manner: under other conditions, the test electrostatic voltage is applied to the first resistance layer having a certain roughness three times with a 10-second interval time using the forward direction, and then applied to the first resistance layer three times with a 10-second interval time using the reverse direction. And gradually increasing the testing electrostatic voltage, and taking the testing electrostatic voltage which breaks through the first resistance layer as the electrostatic discharge resistant voltage of the first resistance layer.

TABLE 1

Rz(μm)	Resisting electrostatic discharge voltage (KV)
		0.1	0.51
1	1.22
		2	1.57
4	2.25
		6	3.15
10	3.49
		30	4.1

As shown in table 1, the different roughness Rz has different esd voltages, that is, the roughness Rz of the first resistance layer is adjusted by providing a protrusion structure on at least a partial region of the first resistance layer on the side away from the first conductive layer, so that the esd voltage of the first resistance layer can be increased.

Table 2 shows the test results obtained by performing the ESD resistance test on the first resistance layers with different roughness Sdr, in the same manner as above.

TABLE 2

As shown in table 2, different roughness Sdr have different electrostatic discharge voltage resistances, that is, by providing a protruding structure on at least a partial region of the first resistance layer on the side away from the first conductive layer, the roughness Sdr of the first resistance layer is adjusted, so that the electrostatic discharge voltage resistance of the first resistance layer can be improved.

In the embodiment of the present invention, the shape of the second protrusion structure 121 may have a variety of shapes according to actual needs, and may be a regular or irregular solid geometry, for example, the shape of the second protrusion structure 121 may be one or more of a sharp corner shape, an inverted cone shape, a granular shape, a dendritic shape, a columnar shape, a block shape, and an arc shape, and the embodiment of the present invention is not limited herein.

In order to further improve the ESD resistance (i.e., the ESD resistance) of the first resistance layer 130, the second protrusion structures 131 are continuously disposed on at least partial regions of both sides of the first resistance layer 130. Illustratively, as shown in fig. 1A, the second protruding structures 131 are dendritic, and the second protruding structures 131 are continuously distributed on at least a partial region of the first resistive layer 130; as shown in fig. 1B, the second protruding structures 131 are arc-shaped, and the second protruding structures 131 are continuously distributed on at least a partial region of the first resistive layer 130 to form a structure similar to a "sine line" shape on both sides of the first resistive layer 130. In addition, in other embodiments of the present invention, the second protrusion structure may include a continuous undulating surface formed on both sides of the first resistance layer, and a plurality of protrusions formed on the undulating surface, and the embodiments of the present invention are not limited herein. In addition, in still other embodiments of the present invention, at least partial areas of the second protruding structures on both sides of the first resistive layer may also be discontinuously distributed, and the embodiments of the present invention are not limited herein.

In some embodiments of the present invention, the dielectric layer 110 and the adjustment layer 120 may be made of resin adhesive, Polyimide (PI), modified polyimide, fiberglass cloth composite material, paper substrate, composite substrate, HDI plate, modified epoxy resin, modified acrylic resin, polyethylene terephthalate, glycol ester, polybutylene terephthalate, polyethylene, etc. for protecting the first resistance layer 130 from being damaged by external force, such as the first resistance layer 130.

In some embodiments of the present invention, at least a partial region of the adjusting layer 120 is provided with a filler, so that at least a partial region of a side of the adjusting layer 120 away from the dielectric layer 110 is formed with a first protrusion structure 121. The roughness of first resistance layer 130 is adjusted by adjusting the type and size of the seasoning so that the side of adjusting layer 120 away from dielectric layer 110 has different roughness.

Fig. 2A is a schematic structural diagram of another composite metal foil provided in the embodiment of the present invention, fig. 2B is a schematic structural diagram of another composite metal foil provided in the embodiment of the present invention, and fig. 2C is a schematic structural diagram of another composite metal foil provided in the embodiment of the present invention, as shown in fig. 2A, fig. 2B, and fig. 2C, in the embodiment, the composite metal foil includes a dielectric layer 210, an adjustment layer 220, a first resistance layer 230, and a first conductive layer 240.

In particular, the dielectric layer 210 may be an insulating base layer for carrying the adjustment layer 220. The adjustment layer 220 may be an insulating material, which may be the same or different from the dielectric layer 210. First resistive layer 230 is a key functional layer of the composite metal foil for performing the resistive function of the composite metal foil. The material of the first resistance layer 230 may include at least one elementary metal of nickel, chromium, platinum, palladium, titanium, and/or an alloy including at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. For example, nickel chromide (NiCr) or nickel phosphide (NiP) with low resistivity, or chromium silicon alloy (CrSi) with high resistivity. In one embodiment of the present invention, the material of the first resistance layer 230 is nickel chromide. The first conductive layer 240 has good conductive performance, and the material of the metal layer may be gold, silver, copper, or aluminum, or an alloy of at least two of them.

At least partial region of the side of the adjusting layer far from the dielectric layer is provided with a first convex structure, and exemplarily, as shown in fig. 2A, 2B and 2C, all regions of the side of the adjusting layer 220 close to the first resistive layer 230 are provided with first convex structures 221. Since the first resistance layer 230 is sequentially formed on the side of the adjustment layer 220 where the first protrusion structures 221 are disposed, the entire areas of both sides of the first resistance layer 230 are formed to conform to the second protrusion structures 231. Since the second protrusion structures 231 are disposed on the entire sides of the first resistance layer 230, the sectional area of the first resistance layer 230 can be further increased, and the anti-electrostatic breakdown capability of the embedded resistor can be improved.

Specifically, roughness Rz of both sides of first resistance layer 230 ranges from 0.1 μm or more, and roughness Sdr ranges from 0.5% or more. It should be noted that, in the embodiment of the present invention, the roughness Rz of the two sides of the first resistance layer 230 may be the same or different, and the roughness Sdr of the two sides of the first resistance layer 230 may be the same or different, which is not limited herein. Preferably, the roughness Rz of both sides of the first resistance layer 230 ranges from 0.1 μm to 30 μm, including 0.1 μm and 30 μm, and the roughness Rz of both sides of the first resistance layer 230 may also take the values of 1 μm, 5 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, and the like. The roughness Sdr may range from 0.5% to 8000%, including 0.5% and 8000%, and may also take on values of 1%, 5%, 12%, 20%, 50%, 80%, 100%, 200%, 500%, 800%, 1500%, 2000%, 2500%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 7500%, and the like.

In the embodiment of the present invention, the shape of the second protrusion structure may have a variety according to actual needs, and may be a regular or irregular solid geometry, which is not limited herein. In some examples, the second protruding structures may form a continuous undulating surface on both sides of the first resistance layer, may form a more regular "sine line" shape on both sides of the first resistance layer, or may form one or more of a sharp corner shape, an inverted cone shape, a granular shape, a dendritic shape, a columnar shape, a block shape, and an arc shape.

In the embodiment of the invention, as shown in fig. 2C, in order to further improve the ESD resistance of the first resistance layer 230, the second protrusion structures 231 disposed in all regions of both sides of the first resistance layer 230 are continuously disposed, that is, the second protrusion structures 231 are continuously disposed on both sides of the first resistance layer 230, so as to further improve the cross-sectional area of the first resistance layer 230, improve the ESD resistance of the first resistance layer 230, and further improve the anti-electrostatic breakdown capability of the embedded resistor.

Further, if the roughness height parameter Rz of the second protruding structures 231 is set too high, the second protruding structures 231 are easily broken by an external force during application, and the ESD resistance of the first resistance layer 230 is further affected, so the roughness Rz of the first resistance layer 230 is set to be in a range of 0.1 μm to 10 μm, and the roughness Sdr of the first resistance layer 230 is set to be greater than or equal to 20%. By defining the roughness height parameter Rz of the first resistance layer 230 to be 0.1 μm-10 μm and the range of the increase parameter Sdr of the surface area relative to the area of the defined area to be more than or equal to 20%, the second protrusion structures 231 which are continuously and closely arranged are obtained in all the areas on both sides of the first resistance layer 230 (the protrusion structures which are continuously and closely arranged in all the areas are similar to a 'fluff' structure) within a certain height range of the second protrusion structures 231, so that the first resistance layer 230 with a larger cross section is obtained under the condition that the height parameter Rz of the roughness is constant, that is, the second protrusion structures 231 are ensured not to be broken due to the external force, the ESD resistance performance of the first resistance layer 230 is further improved, and the embedded resistance has a stronger anti-electrostatic breakdown capability.

Preferably, roughness Rz of first resistance layer 230 ranges from 0.1 μm to 10 μm, and roughness Sdr of first resistance layer 230 ranges from 50% or more. By defining the roughness height parameter Rz of the first resistance layer 230 to be 0.1 μm-10 μm and the range of the increase parameter Sdr of the surface area relative to the area of the defined area to be more than or equal to 50%, the second protrusion structures 231 which are continuously and closely arranged are obtained in all the areas on both sides of the first resistance layer 220 within a certain height range of the second protrusion structures 231, that is, the protrusion structures which are closely arranged are obtained in the range of more than or equal to 20% of the roughness Sdr, so that the cross section of the first resistance layer is further increased, the ESD resistance of the first resistance layer is further improved, and the embedded resistance is effectively ensured to have stronger anti-static breakdown capability.

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 200% or more, so as to further increase the cross section of the first resistance layer, further improve the ESD resistance of the first resistance layer, and effectively ensure that the embedded resistance has excellent anti-electrostatic breakdown capability.

In some embodiments of the present invention, the dielectric layer 210 and the adjustment layer 220 may be made of resin adhesive, Polyimide (PI), modified polyimide, fiberglass cloth composite material, paper substrate, composite substrate, HDI plate, modified epoxy resin, modified acrylic resin, polyethylene terephthalate, glycol ester, polybutylene terephthalate, polyethylene, etc. for protecting the first resistance layer 230 from being damaged by external force.

In some embodiments of the present invention, the entire area of the adjusting layer 220 is provided with the filler, so that at least a partial area of the side of the adjusting layer 220 away from the dielectric layer 110 is formed with the first protrusion structure 221. The roughness of first resistive layer 230 is adjusted by adjusting the type and size of the seasoning such that the side of adjustment layer 220 away from dielectric layer 210 has a different roughness.

Fig. 3 is a schematic structural diagram of another composite metal foil according to an embodiment of the present invention, as shown in fig. 3, in this embodiment, the composite metal foil includes a dielectric layer 310, an adjustment layer 320, a first resistive layer 330, and a first conductive layer 340.

In particular, dielectric layer 310 may be an insulating base layer for carrying conditioning layer 320. Adjustment layer 320 may be an insulating material, which may be the same or different from dielectric layer 310. The first resistance layer 330 is a key functional layer of the composite metal foil, and is used for realizing the resistance function of the composite metal foil. The material of the first resistance layer 330 may include at least one elemental metal of nickel, chromium, platinum, palladium, titanium, and/or an alloy including at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. For example, nickel chromide (NiCr) or nickel phosphide (NiP) with low resistivity, or chromium silicon alloy (CrSi) with high resistivity. In an embodiment of the present invention, the material of the first resistance layer 330 is nickel chromide. The first conductive layer 340 has good conductive performance, and the material of the metal layer may be gold, silver, copper, or aluminum, or an alloy of at least two of them, etc.

At least partial area of the side of the adjusting layer far away from the dielectric layer is provided with a first protruding structure, for example, as shown in fig. 3, all area of the side of the adjusting layer 320 near the first resistance layer 330 is provided with a first protruding structure 321, and the plurality of first protruding structures 321 are continuous to form a wavy surface. Since the first resistance layer 330 is sequentially formed on the side of the adjustment layer 320 where the first protruding structures 321 are disposed, the entire area of the two sides of the first resistance layer 330 is formed to conform to the second protruding structures 331, and the second protruding structures 331 enable the first resistance layer 330 to form a continuous wavy structure.

Specifically, the roughness Rz of both sides of the first resistance layer 330 ranges from 0.1 μm or more, and the roughness Sdr ranges from 0.5% or more. It should be noted that, in the embodiment of the present invention, the roughness Rz of the two sides of the first resistance layer 330 may be the same or different, and the roughness Sdr of the two sides of the first resistance layer 330 may be the same or different, which is not limited herein. Preferably, the roughness Rz of both 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 both sides of the first resistance layer 330 may also take on the values of 1 μm, 5 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, and the like. The roughness Sdr may range from 0.5% to 8000%, including 0.5% and 8000%, and may also take on values of 1%, 5%, 12%, 20%, 50%, 80%, 100%, 200%, 500%, 800%, 1500%, 2000%, 2500%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 7500%, and the like.

In some embodiments of the present invention, the dielectric layer 310 and the adjustment layer 320 may be made of resin adhesive, Polyimide (PI), modified polyimide, fiberglass cloth composite material, paper substrate, composite substrate, HDI plate, modified epoxy resin, modified acrylic resin, polyethylene terephthalate, glycol ester, polybutylene terephthalate, polyethylene, etc. for protecting the first resistance layer 330 from being damaged by a force from the outside.

In some embodiments of the present invention, the entire area of the adjusting layer 320 is provided with the filler, so that at least a partial area of the side of the adjusting layer 320 away from the medium layer 310 is formed with the first protrusion structure 321. The roughness of the first resistance layer 330 is adjusted by adjusting the type and size of the seasoning so that the side of the adjusting layer 320 away from the dielectric layer 310 has different roughness.

Furthermore, a second resistance layer and a second conductive layer are arranged on one side, far away from the first resistance layer, of the dielectric layer, and the second resistance layer is located between the dielectric layer and the second conductive layer. The materials and purposes of the second resistance layer and the first resistance layer can be the same or different, and the materials and purposes 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 resistance layer may be the same as those of the first resistance layer, and the structure and parameters of the second conductive layer may also be the same as those of the first conductive layer, which is not repeated herein. Further, in some embodiments of the present invention, an adjusting layer may be further disposed between the dielectric layer and the second resistive layer, and the adjusting layer between the dielectric layer and the first resistive layer may have the same structure, material, and parameters, and have the same function.

Fig. 4A is a schematic structural diagram of another composite metal foil provided in the embodiment of the present invention, and fig. 4B is a schematic structural diagram of another composite metal foil provided in the embodiment of the present invention, as shown in fig. 4A and fig. 4B, in the embodiment, the composite metal foil includes a dielectric layer 410, an adjustment layer 420, a first resistance layer 430, a first conductive layer 440, a second resistance layer 450, and a second conductive layer 460.

The adjustment layer 420 is formed on one side of the dielectric layer 410, the first resistive layer 430 is formed on one side of the adjustment layer 420 remote from the dielectric layer 410, and the first conductive layer 440 is formed on one side of the first resistive layer 430 remote from the adjustment layer 420. The entire area of the side of the adjusting layer 420 away from the dielectric layer is provided with the first protrusion structures 421, so that the adjusting layer 420 has a concave-convex surface, and two sides of the formed first resistance layer 430 are conformed to form the second protrusion structures 431. The materials of the first conductive layer, the first resistance layer, the adjusting layer and the dielectric layer, the shape of the second protrusion structure and the roughness of the two sides of the first resistance layer are described in detail in the foregoing embodiments, and no further description is given in the embodiments of the present invention.

A second resistive layer 450 is disposed on a side of dielectric layer 410 remote from tuning layer 420 and a second conductive layer 460 is disposed on a side of second resistive layer 450 remote from dielectric layer 410. In one embodiment of the present invention, the materials and purposes of the second resistive layer 450 and the first resistive layer 430 are the same, and the materials and purposes of the second conductive layer 460 and the first conductive layer 440 are the same.

One or both sides of the second resistive layer 450 may be flat, or at least a portion of the second resistive layer may be provided with a protrusion structure, similar to the first resistive layer 430. Illustratively, as shown in fig. 4A, the side of the second resistance layer 450 far from the dielectric layer 410 is provided with a raised structure; as shown in fig. 4B, the protrusion structures are disposed in all the areas on both sides of the second resistance layer 450, and the protrusion structures may refer to the protrusion structures on the first resistance layer 430 described in the foregoing embodiments of the present invention, which are not described herein again.

Fig. 5A is a flowchart of a method for manufacturing a composite metal foil according to an embodiment of the present invention, and as shown in fig. 5A, the method includes:

s501, providing a dielectric layer.

Specifically, the dielectric layer may be resin adhesive, Polyimide (PI), modified polyimide, fiberglass cloth composite material, paper substrate, composite substrate, HDI plate, modified epoxy resin, modified acrylic resin, polyethylene terephthalate, glycol ester, polybutylene terephthalate, polyethylene, and the like.

And S502, forming a regulating layer on one side of the medium layer.

Specifically, the adjustable layer may be an insulating material, and the material of the adjustable layer may be the same as or different from that of the dielectric layer, and the embodiment of the invention is not limited herein. Illustratively, the precursor solution of the adjusting layer is coated on one side of the medium layer to obtain the adjusting layer, or the adjusting layer can be directly attached to the medium layer.

Fig. 5B is a schematic diagram of forming a regulating layer on a dielectric layer according to an embodiment of the present invention, and as shown in fig. 5B, a regulating layer 520 is formed on one side of the dielectric layer 510.

S503, forming a first protruding structure on at least a partial region of one side of the adjusting layer far away from the medium layer.

Specifically, the side of the adjustment layer away from the dielectric layer may be roughened, and the roughening treatment may include, but is not limited to, physical grinding, chemical etching, shot blasting, sand blasting, and the like. After coarsening treatment, a first bulge structure is formed in at least a partial area of one side of the adjusting layer, which is far away from the medium layer. In addition, the first convex structure can also be formed in at least partial region of one side of the adjusting layer far away from the medium layer by arranging the filler in the adjusting layer.

In some embodiments of the invention, at least a partial region of the regulating layer is provided with a filler, so that at least a partial region of a side of the regulating layer remote from the medium layer is formed with a first convex structure. By adjusting the type and the size of the seasoning, one side of the adjusting layer, which is far away from the dielectric layer, has different roughness, so that the roughness of the first resistance layer is adjusted.

Fig. 5C is a schematic diagram of forming a first bump structure on a side of the adjusting layer away from the dielectric layer according to an embodiment of the present invention, and as shown in fig. 5C, a first bump structure 521 is formed in the entire area of the side of the adjusting layer 520 away from the dielectric layer 510. The shape of the first bump structure 521 may have a variety according to actual needs, and may be a regular or irregular solid geometry, and the embodiment of the invention is not limited herein. In some examples, the first raised structure provides the regulation layer with a continuous undulating surface forming a more regular sinusoidal line shape, or the first raised structure may have one or more of a pointed shape, an inverted conical shape, a granular shape, a dendritic shape, a columnar shape, a block shape, and an arc shape.

And S504, forming a first resistance layer on one side of the adjusting layer far away from the dielectric layer.

Specifically, the first resistance layer may be formed on a side of the adjustment layer away from the dielectric layer by physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, hybrid plating, and the like. The first resistance layer is a key functional layer of the composite metal foil and is used for realizing the resistance function of the composite metal foil. The material of the first resistance layer may include at least one elemental metal of nickel, chromium, platinum, palladium, titanium, and/or an alloy including a combination of at least two of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. For example, 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, and the embodiments of the present invention are not limited thereto. In some embodiments of the present invention, the first resistive layer may be a single layer structure or at least a two-layer structure. Any layer can be made of any metal of nickel, chromium, platinum, palladium and titanium, or can be made of an alloy of at least two of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus and aluminum.

Fig. 5D is a schematic diagram of forming a first resistance layer on the adjusting layer according to the embodiment of the invention, and as shown in fig. 5D, the first resistance layer 530 is formed on a side of the adjusting layer 520 away from the dielectric layer 510. Since the first protruding structures 521 are formed on the adjustment layer 520, the two sides of the first resistance layer 530 are conformed to form the second protruding structures 531. The shape of the second protrusion structure may have a variety according to actual needs, and may be a regular or irregular solid geometry, and the embodiment of the present invention is not limited herein. In some examples, the second protruding structure may form a continuous undulating surface on both sides of the first resistance layer, or form a more regular sine line shape on both sides of the first resistance layer, or form one or more shapes of a sharp corner, an inverted cone, a particle, a tree, a column, a block, and an arc shape, or form a continuous undulating structure on the first resistance layer by the second protruding structure.

Specifically, the roughness Rz of both sides of the first resistance layer 530 ranges from 0.1 μm or more, and the roughness Sdr ranges from 0.5% or more. It should be noted that, in the embodiment of the present invention, the roughness Rz of the two sides of the first resistance layer 530 may be the same or different, and the roughness Sdr of the two sides of the first resistance layer 530 may be the same or different, which is not limited herein. Preferably, the roughness Rz of both sides of the first resistance layer 520 ranges from 0.1 μm to 30 μm, including 0.1 μm and 30 μm, and the roughness Rz of both sides of the first resistance layer 520 may also take on the values of 1 μm, 5 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, and the like. The roughness Sdr may range from 0.5% to 8000%, including 0.5% and 8000%, and may also take on values of 1%, 5%, 12%, 20%, 50%, 80%, 100%, 200%, 500%, 800%, 1500%, 2000%, 2500%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 7500%, and the like.

Because the appearance and the roughness of the two sides of the first resistance layer are determined by the adjusting layer, the appearance and the roughness of the two sides of the first resistance layer can be adjusted by changing the shape and the size of the first protruding structure on the adjusting layer, and the product performance of the embedded resistor can be accurately adjusted.

And S505, forming a first conductive layer on one side of the first resistance layer far away from the adjusting layer.

Specifically, the first conductive layer may be formed on a side of the first resistance layer away from the adjustment layer by physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating, hybrid plating, or the like. The first conductive layer has good conductive performance, and the material of the metal layer can be gold, silver, copper or aluminum, or an alloy of at least two of the gold, silver, copper or aluminum.

Fig. 5E is a schematic diagram of forming a first conductive layer on the first resistance layer according to an embodiment of the invention, and as shown in fig. 5E, a first conductive layer 540 is formed on a side of the first resistance layer 530 away from the adjustment layer 520.

Furthermore, a second resistance layer and a second conductive layer can be arranged on one side, far away from the adjusting layer, of the dielectric layer, and the second resistance layer is located between the dielectric layer and the second conductive layer.

The preparation method of the composite metal foil provided by the embodiment of the invention comprises the following steps: providing a medium layer, forming an adjusting layer on one side of the medium layer, forming a first bulge structure in at least a partial region of one side of the adjusting layer far away from the medium layer, forming a first resistance layer on one side of the adjusting layer far away from the medium layer, and forming a first conducting layer on one side of the first resistance layer far away from the adjusting layer. Through the method, the second protruding structures are formed on two sides of the first resistance layer. Due to the existence of the second protruding structure, the sectional area of the first resistance layer is increased, the current-carrying capacity of the first resistance layer is improved, the ESD performance of the first resistance layer is further improved, and the antistatic breakdown performance of the embedded resistor is further improved.

The embodiment of the invention also provides a circuit board which comprises the composite metal foil provided by any embodiment of the invention.

The circuit board provided by the embodiment of the invention has the corresponding functions and beneficial effects with the composite metal foil provided by the embodiment of the invention.

In the description herein, it is to be understood that the terms "upper", "lower", "left", "right", and the like are used in a descriptive sense or positional relationship based on the orientation or positional relationship shown in the drawings for convenience in description and simplicity of operation, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the present invention.

In the description herein, references to the description of "an embodiment," "an example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be appropriately combined to form other embodiments as will be appreciated by those skilled in the art.

The technical principle of the present invention is described above in connection with specific embodiments. The description is made for the purpose of illustrating the principles of the invention and should not be taken in any way as limiting the scope of the invention. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without inventive effort, which would fall within the scope of the present invention.

Claims

1. A composite metal foil, comprising: the resistance adjusting device comprises a dielectric layer, an adjusting layer, a first resistance layer and a first conducting layer;

the adjusting layer is arranged on one side of the medium layer;

2. The composite metal foil according to claim 1, wherein the roughness Rz of the first resistive layer on the side closer to the adjustment layer and on the side farther from the adjustment layer each range from 0.1 μ ι η to 30 μ ι η.

3. The composite metal foil as claimed in claim 1, wherein the roughness Sdr ranges from both the side of the first resistance layer close to the adjustment layer and the side far from the adjustment layer to 0.5% or more.

4. The composite metal foil as claimed in claim 1, wherein all areas of a side of the regulating layer remote from the dielectric layer are provided with the first protrusion structures, such that all areas of a side of the first resistive layer close to the regulating layer and a side remote from the regulating layer form the second protrusion structures.

5. The composite metal foil as claimed in claim 1, wherein at least a partial region of a side of the adjustment layer remote from the dielectric layer is provided with a plurality of continuous first bump structures, such that at least a partial region of a side of the first resistance layer close to the adjustment layer and a side remote from the adjustment layer form a plurality of continuous second bump structures.

6. The composite metal foil as claimed in claim 5, wherein the first plurality of raised structures are provided in a plurality of continuous regions on a side of the adjustment layer remote from the dielectric layer, such that the second plurality of raised structures are formed in a plurality of continuous regions on a side of the first resistance layer remote from the adjustment layer and a side of the first resistance layer remote from the adjustment layer.

7. The composite metal foil according to claim 5, wherein the entire area of the side of the first resistive layer adjacent to the adjustment layer and the side thereof remote from the adjustment layer forms a continuous second bump structure, so that the first resistive layer forms a continuous wave structure.

8. The composite metal foil according to any one of claims 1 to 7, wherein the roughness Rz of the first resistance layer on the side closer to the adjustment layer and the roughness dr of the first resistance layer on the side farther from the adjustment layer each range from 0.1 μm to 10 μm, and the roughness Sdr of the first resistance layer on the side closer to the adjustment layer and the roughness dr of the first resistance layer on the side farther from the adjustment layer each range from 20% or more.

9. The composite metal foil according to any one of claims 1 to 7, wherein the roughness Rz of the first resistance layer on the side closer to the adjustment layer and the roughness dr of the first resistance layer on the side farther from the adjustment layer each range from 0.1 μm to 10 μm, and the roughness Sdr of the first resistance layer on the side closer to the adjustment layer and the roughness dr of the first resistance layer on the side farther from the adjustment layer each range from 50% or more.

10. The composite metal foil according to any one of claims 1 to 7, wherein the roughness Rz of the first resistance layer on the side close to the adjustment layer and the roughness Rz of the first resistance layer on the side far from the adjustment layer are each in a range of 0.1 μm to 10 μm, and the roughness Sdr of the first resistance layer on the side close to the adjustment layer and the roughness Sdr of the first resistance layer on the side far from the adjustment layer are each in a range of 200% or more.

11. The composite metal foil of any one of claims 1 to 7, wherein a second resistive layer and a second conductive layer are provided on a side of said dielectric layer remote from said regulating layer, said second resistive layer being located between said dielectric layer and said second conductive layer.

12. The composite metal foil according to any one of claims 1 to 7, wherein the material of the first resistance layer comprises at least one elemental metal selected from nickel, chromium, platinum, palladium, and titanium, and/or an alloy comprising a combination of at least two selected from nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum.

13. The composite metal foil according to claim 12, wherein the first resistive layer is a single layer structure or at least a two layer structure.

14. A wiring board comprising the composite metal foil as claimed in any one of claims 1 to 13.