WO2022104995A1 - Composite metal foil and circuit board - Google Patents

Abstract

A composite metal foil and a circuit board. The composite metal foil comprises a dielectric layer (110), a first resistance layer (120) and a first conductive layer (130), wherein the first resistance layer (120) is arranged on one side of the dielectric layer (110); at least part of an area on the side of the dielectric layer (110) close to the first resistance layer (120) is configured with a first protruding structure (111), so that second protruding structures (121) are respectively formed in at least part of an area on the side of the first resistance layer (120) close to the dielectric layer (110) and in at least part of an area on the side of the first resistance layer away from the dielectric layer (110); and the first conductive layer (130) is arranged on the side of the first resistance layer (120) away from the dielectric layer (110).

Description

A composite metal foil and circuit board technical field

The application belongs to the technical field of composite metal foils, and relates to a composite metal foil and a circuit board.

Background technique

With the rapid development of wireless communication and electronic equipment, the electronic equipment is evolving towards precision, miniaturization and thinning. Therefore, the size of the components inside the electronic equipment is required to be miniaturized and thinned as much as possible.

The resistive elements inside electronic equipment have gradually developed into thin and light from the previous plug-in resistors with pins, to chip resistors, and then to embedded resistors. The preparation process of the embedded resistor is roughly as follows: the composite metal foil is attached to the circuit board, and the embedded resistor is etched through an etching process.

Application of embedded resistors There are many embedded resistors integrated on the circuit board inside the terminal electronic product, and the circuit is quite sensitive to electrostatic high voltage. When a person or object with static electricity touches these embedded resistors, electrostatic discharge will be generated. , When the electrostatic high voltage hits the circuit, it is easy to be broken down by the electrostatic high voltage, thus making the embedded resistor function invalid.

SUMMARY OF THE INVENTION

One purpose of the embodiments of the present application is to provide a composite metal foil, which can improve the current carrying capacity of the first resistance layer, thereby improving the ESD (Electro-Static Discharge, electrostatic discharge) resistance of the first resistance layer, thereby improving the embedded resistance antistatic breakdown capability.

Another object of the embodiments of the present application is to provide a circuit board prepared from the composite metal foil provided by the embodiments of the present application.

Another object of the embodiments of the present application is to provide a circuit board including the composite metal foil provided by the embodiments of the present application.

To achieve the above purpose, the application adopts the following technical solutions:

In a first aspect, an embodiment of the present application provides a composite metal foil, including: a dielectric layer, a first resistance layer, and a first conductive layer;

the first resistance layer is arranged on one side of the dielectric layer;

At least part of the area of the side of the dielectric layer close to the first resistance layer is provided with a first protruding structure, so that the side of the first resistance layer close to the dielectric layer and a side away from the dielectric layer are provided. At least part of the area of the side is formed with a second protruding structure;

The first conductive layer is disposed on a side of the first resistance layer away from the dielectric layer.

Optionally, at least a partial region of the side of the dielectric layer away from the first resistance layer is provided with a first protruding structure.

Optionally, at least part of the dielectric layer is provided with fillers, so that at least part of the areas on both sides of the dielectric layer have first protruding structures.

Optionally, the roughness Rz of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both in the range of 0.1 μm-30 μm.

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

Optionally, the entire area of the side of the dielectric layer close to the first resistance layer is provided with a first protruding structure, so that the first resistance layer is close to the side of the dielectric layer and away from the medium. The entire area of one side of the layer is formed with the second protruding structure.

Optionally, at least a partial area of the side of the dielectric layer close to the first resistance layer is provided with a plurality of continuous first protrusion structures, so that the first resistance layer is close to the side of the dielectric layer A plurality of continuous raised structures are formed with at least a part of the area on one side away from the dielectric layer.

Optionally, the entire area of the side of the dielectric layer close to the first resistance layer is provided with a plurality of continuous first protruding structures, so that the first resistance layer is close to the side of the dielectric layer and A plurality of continuous protruding structures are formed in the entire region on the side away from the dielectric layer.

Optionally, the entire region of the first resistance layer on the side close to the dielectric layer and the side away from the dielectric layer forms continuous second raised structures, so that the first resistance layer forms a continuous second protrusion structure. undulating structure.

Optionally, the roughness Rz of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both in the range of 0.1 μm-10 μm, and the first resistance layer is close to the medium The range of the roughness Sdr of the side of the layer and the side away from the dielectric layer is greater than or equal to 20%.

Optionally, the roughness Rz of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both in the range of 0.1 μm-10 μm, and the first resistance layer is close to the medium The range of the roughness Sdr of the side of the layer and the side away from the dielectric layer is greater than or equal to 50%.

Optionally, the roughness Rz of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both in the range of 0.1 μm-10 μm, and the first resistance layer is close to the medium The range of the roughness Sdr of the side of the layer and the side away from the dielectric layer is greater than or equal to 200%.

Optionally, a second resistance layer and a second conductive layer are provided on the side of the dielectric layer away from the first resistance 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 elemental metal selected from nickel, chromium, platinum, palladium, and titanium, and/or includes nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. Alloys of at least two combinations.

Optionally, the first resistance layer has a single-layer structure or at least a two-layer structure.

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

The composite metal foil provided by the embodiment of the present application includes a dielectric layer, a first resistance layer and a first conductive layer, the first resistance layer is disposed on one side of the dielectric layer, and the dielectric layer is close to at least a part of the area on the side of the first resistance layer A first protruding structure is provided, so that the second protruding structure is formed in at least part of the region of the first resistive layer on the side close to the dielectric layer and on the side far from the dielectric layer, and the first conductive layer is disposed far from the first resistive layer. side of the dielectric 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 resistance of the first resistance layer, thereby improving the resistance of the embedded resistance layer. Electrostatic breakdown capability.

Description of drawings

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

FIG. 1A is a schematic structural diagram of a composite metal foil provided by an embodiment of the present application;

FIG. 1B is a schematic structural diagram of another composite metal foil provided by an embodiment of the present application;

2A is a schematic structural diagram of another composite metal foil provided by an embodiment of the present application;

2B is a schematic structural diagram of another composite metal foil provided by an embodiment of the present application;

2C is a schematic structural diagram of another composite metal foil provided by an embodiment of the present application;

3 is a schematic structural diagram of another composite metal foil provided by an embodiment of the present application;

4A is a schematic structural diagram of another composite metal foil provided by an embodiment of the present application;

4B is a schematic structural diagram of another composite metal foil provided by an embodiment of the present application;

5A is a flowchart of a method for preparing a composite metal foil provided by an embodiment of the present application;

5B is a schematic diagram of forming a first protruding structure on one side of a dielectric layer according to an embodiment of the present application;

5C is a schematic diagram of forming a first resistance layer on a dielectric layer according to an embodiment of the present application;

FIG. 5D is a schematic diagram of forming a first conductive layer on the first resistance layer according to an embodiment of the present application.

Detailed ways

In order to make the technical problems solved by the application, the technical solutions adopted and the technical effects achieved more clearly, the technical solutions of the embodiments of the application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only the application. Some examples, but not all examples. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

In the description of this application, unless otherwise expressly specified and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integrated ; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood in specific situations.

In this application, unless otherwise expressly specified and defined, a first feature "on" or "under" a second feature may include direct contact between the first and second features, or may include the first and second features Not directly but through additional features between them. Also, the first feature being "above", "over" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature is "below", "below" and "below" the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature has a lower level than the second feature. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

FIG. 1A is a schematic structural diagram of a composite metal foil provided by an embodiment of the present application, and FIG. 1B is a schematic structural schematic diagram of another composite metal foil provided by an embodiment of the present application. As shown in FIGS. 1A and 1B , in this embodiment , the dielectric layer 110 , the first resistance layer 120 and the first conductive layer 130 .

Specifically, the dielectric layer 110 may be an insulating base layer for carrying the first resistance layer 120 . Exemplarily, the material of the dielectric layer 110 may be polyimide or resin with certain flexibility and buffering effect. The first protruding structure 111 is provided on at least a partial area of the side of the dielectric layer 110 close to the first resistance layer 120 , so that the dielectric layer 110 has a concave-convex surface.

The first resistance layer 120 is a key functional layer of the composite metal foil, and is used to realize the resistance function of the embedded resistance. Generally, the resistor 120 can be made of different materials according to the requirements of different functions, thereby having different resistance characteristics.

The material of the first resistance layer 120 may include any one element metal among nickel, chromium, platinum, palladium, and titanium, and/or at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. alloy. For example, nickel-chromium alloy (NiCr) or nickel-phosphorus alloy (NiP) with low resistivity may also be chromium-silicon alloy (CrSi) with high resistivity, which is not limited in this embodiment of the present application. The first resistive layer 120 serves as a precursor of the first resistive layer in the embedded resistor. In other words, the first resistive layer in the embedded resistor is obtained by removing part of the first resistive layer 120 through processes such as etching. The thickness of the first resistance layer 120 ranges from 0.01 μm to 0.5 μm. It should be noted that the high resistivity and low resistivity in the embodiments of the present application are for the first resistance layer itself, not for the first conductive layer.

In some embodiments of the present application, the first resistance layer 120 has a single-layer structure or at least a two-layer structure. Exemplarily, the single-layer structure may be a single-layer structure composed of any one of nickel, chromium, platinum, palladium, and titanium, or may be at least one of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. A single-layer structure composed of two combined alloys. Any layer in the at least two-layer structure can be any one of nickel, chromium, platinum, palladium, titanium to form an elemental metal, or it can be at least one of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. Two alloys in combination. The thickness of the first resistance layer 120 ranges from 0.01 μm to 0.5 μm.

The first conductive layer 130 has good electrical conductivity, and the material of the metal layer can be gold, silver, copper or aluminum, or an alloy of at least two of them. In other embodiments of the present application, the first conductive layer 130 may also be other non-metallic layers with good conductivity. The embodiment of the present application does not limit the material of the first conductive layer, as long as it has good conductivity. The thickness of the first conductive layer 130 ranges from 3 μm to 18 μm.

The first resistance layer 120 is formed on one side of the dielectric layer 110. Specifically, in one of the embodiments of the present application, the dielectric layer 110 can be prepared in advance, and then can be deposited by physical vapor deposition, chemical vapor deposition, evaporation, or sputtering. The first resistive layer 120 is formed on one side of the dielectric layer 110 by methods such as electroplating, electroplating, and mixed plating. Since at least part of the area of the side of the dielectric layer 110 close to the first resistance layer 120 is provided with the first protruding structures 111 , so that the dielectric layer 110 has a concave-convex surface, the first resistance layer 120 formed on the dielectric layer 110 will The protruding structures are formed compliantly, so that the second protruding structures 121 are formed on both sides of the formed first resistance layer 120 .

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

In this embodiment of the present application, the second protruding structures 121 are formed on at least partial regions on both sides of the first resistance layer 120 , so that the first resistance layer 120 has a rough surface. The existence of the second protruding structure 121 increases the cross-sectional area of the first resistance layer 120 , improves the current carrying capacity of the first resistance layer 120 , and further improves the ESD resistance of the first resistance layer, thereby improving the embedded type Antistatic breakdown performance of resistors.

The composite metal foil provided by the embodiment of the present application includes a dielectric layer, a first resistance layer and a first conductive layer, the first resistance layer is disposed on one side of the dielectric layer, and the dielectric layer is close to at least a part of the area on the side of the first resistance layer A first protruding structure is provided, so that at least partial regions on both sides of the first resistive layer are formed with a second protruding structure, and the first conductive layer is provided on the side of the first resistive layer away from the dielectric 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 resistance of the first resistance layer, thereby improving the resistance of the embedded resistance layer. Electrostatic breakdown capability.

In some embodiments of the present application, the range of the roughness Rz of at least part of the regions on both sides of the first resistance layer 120 (regions provided with the protruding structures) is greater than or equal to 0.1 μm, and the range of the roughness Sdr is greater than or equal to 0.1 μm. 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 120. Specifically, the average value of the five largest contour peak heights and the five largest contour valley depths in the sampling length are usually averaged. The sum of the values is taken as the roughness Rz. The roughness Sdr is the expanded area (surface area) of the defined area, which indicates how much the area of the defined area has increased, wherein the roughness Sdr of a completely flat surface is zero. It should be noted that, in the embodiment of the present application, the roughness Rz on both sides of the first resistance layer 120 may be the same or different, and the roughness Sdr on both sides of the first resistance layer 120 may be the same or different, The embodiments of the present application are not limited herein. It should be noted that, in this embodiment and subsequent embodiments, the test standard of roughness is the ISO25178 standard.

Further, in some embodiments of the present application, in order to further improve the ESD resistance of the first resistance layer, the roughness Rz on both sides of the first resistance layer 120 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 120 may also be 1 μm, 5 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, and the like. The range of roughness Sdr is 0.5%-8000%, including 0.5% and 8000%, and the value of 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.

Table 1 shows the test results obtained from the ESD resistance test of the first resistance layer with different roughness Rz. On one resistive layer, apply three times with an interval of 10 seconds each, and then apply a reverse test electrostatic voltage to the first resistive layer for three times with an interval of 10 seconds each. The test electrostatic voltage is gradually increased, and the test electrostatic voltage that breaks down the first resistance layer is used as the electrostatic discharge resistance voltage of the first resistance layer.

Table 1

Rz(μm)	Electrostatic discharge resistance (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, different roughnesses Rz have different electrostatic discharge resistance voltages, that is to say, the first resistance can be adjusted by arranging raised structures in at least part of the region on the side of the first resistance layer away from the first conductive layer. The roughness Rz of the layer can improve the electrostatic discharge resistance voltage of the first resistance layer.

Table 2 shows the test results obtained by performing the ESD resistance test on the first resistance layer with different roughness Sdr, and the test method is the same as before.

Table 2

Sdr(%)	Electrostatic discharge resistance (KV)
0.5	0.53
10	0.76
70	1.45
100	2.18
500	3.07
1000	4.11
8000	4.3

As shown in Table 2, different roughness Sdr has different electrostatic discharge resistance voltage, that is to say, by arranging raised structures in at least part of the region of the side of the first resistance layer away from the first conductive layer, the first resistance can be adjusted. The layer roughness Sdr can improve the electrostatic discharge resistance voltage of the first resistance layer.

In the embodiment of the present application, the shape of the second protruding structure 121 can be diverse according to actual needs, and can be a regular or irregular three-dimensional geometric shape. For example, the shape of the second protruding structure 121 can be a sharp angle. , one or more of inverted cone shape, granular shape, dendritic shape, column shape, block shape, and arc shape, which are not limited in the embodiments of the present application.

In order to further improve the ESD resistance (ie, electrostatic discharge voltage resistance) of the first resistance layer 120 , the second protrusion structures 121 disposed on at least part of both sides of the first resistance layer 120 are continuously disposed. Exemplarily, as shown in FIG. 1A , the shape of the second protruding structures 121 is dendritic, while the second protruding structures 121 are continuously distributed on at least a partial area of the first resistance layer 120 ; or as shown in FIG. 1B . , the shape of the second protruding structures 121 is arc-like, and the second protruding structures 121 are continuously distributed in at least part of the first resistive layer 120 to form a structure similar to a “sine line” shape on both sides of the first resistive layer 120 . In addition, in other embodiments of the present application, the second protruding structure may include a continuous undulating surface formed on both sides of the first resistance layer, and a plurality of protruding portions formed on the undulating surface. Do limit. In addition, in some other embodiments of the present application, at least partial regions of the second protruding structures on both sides of the first resistance layer may also be discontinuously distributed, which is not limited in the embodiments of the present application.

In some embodiments of the present application, the material of the dielectric layer 110 may be resin glue, polyimide (PI), modified polyimide, glass fiber cloth, glass fiber cloth composite material, paper substrate, composite substrate, HDI sheet, modified epoxy resin, modified acrylic resin, polyethylene terephthalate, glycol ester, polybutylene terephthalate, polyethylene, etc., are used to protect the first resistance layer 120 and avoid the A resistive layer 120 is damaged by external force.

In some embodiments of the present application, at least a partial area of the dielectric layer 110 is provided with fillers, so that at least partial areas on both sides of the dielectric layer 110 have the first protruding structures 111 . The dielectric layer 110 is far away from the first protruding structure 111 on the first resistive layer 120 to make the surface rougher. stripped.

2A is a schematic structural diagram of another composite metal foil provided by an embodiment of the application, FIG. 2B is a schematic structural diagram of another composite metal foil provided by an embodiment of the application, and FIG. 2C is another composite metal foil provided by an embodiment of the application. Schematic diagram of the structure of the composite metal foil, as shown in FIG. 2A , FIG. 2B and FIG. 2C , in this embodiment, the composite metal foil includes a dielectric layer 210 , a first resistance layer 220 and a first conductive layer 230 .

Specifically, the dielectric layer 210 may be an insulating base layer for carrying the first resistance layer 220 . The first resistance layer 220 is a key functional layer of the composite metal foil, and is used to realize the resistance function of the composite metal foil. The material of the first resistance layer 220 may include at least one elemental metal selected from nickel, chromium, platinum, palladium, and titanium, and/or at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. alloy. For example, nickel-chromium alloy (NiCr) or nickel-phosphorus alloy (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 220 is a nickel-chromium alloy. In some embodiments of the present application, the first resistance layer 220 may have a single-layer structure or at least a two-layer structure. Exemplarily, the single-layer structure may be a single-layer structure composed of any one of nickel, chromium, platinum, palladium, and titanium, or may be at least one of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. A single-layer structure composed of two combined alloys. Any layer in the at least two-layer structure can be any one of nickel, chromium, platinum, palladium, titanium to form an elemental metal, or it can be at least one of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. Two alloys in combination. The first conductive layer 230 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.

The first resistance layer is formed on one side of the dielectric layer, and at least part of the area of the side of the dielectric layer close to the first resistance layer is provided with a first protruding structure. Exemplarily, the entire region of the dielectric layer 210 on one side of the first resistive layer 220 is provided with the first protruding structure 211, so that the dielectric layer 210 has a concave-convex surface, so that the two sides of the first resistive layer 220 are formed compliantly. The second protruding structure 221 . Since the entire surface on both sides of the first resistive layer 220 is provided with the second protruding structures 221 , the second protruding structures 221 are provided in a partial area, which further increases the cross-sectional area of the first resistive layer 220 and improves the embeddedness. The anti-static breakdown capability of the type resistor.

Specifically, the range of the roughness Rz on both sides of the first resistance layer 220 is greater than or equal to 0.1 μm, and the range of 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 on both sides of the first resistance layer 220 may be the same or different, and the roughness Sdr on both sides of the first resistance layer 220 may be the same or different, The embodiments of the present application are not limited herein. Optionally, the roughness Rz on both sides of the first resistance layer 220 ranges from 0.1 μm to 30 μm, including 0.1 μm and 30 μm, and the value of the roughness Rz on both sides of the first resistance layer 220 can also be 1 μm, 5 μm, 8μm, 9μm, 10μm, 15μm, 20μm, etc. The range of roughness Sdr is 0.5%-8000%, including 0.5% and 8000%, and the value of 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.

In the embodiments of the present application, the shapes of the second protruding structures may have various shapes according to actual needs, and may be regular or irregular three-dimensional geometric shapes, which are not limited in the embodiments of the present application. In some examples, the second protruding structure may form a continuous undulating surface on both sides of the first resistive layer, or may form a relatively regular "sinusoidal" shape on both sides of the first resistive layer, or the shape of the protruding structure It is one or more of sharp angle, inverted cone, granular, dendritic, columnar, block, and arc shape.

In the embodiment of the present application, as shown in FIG. 2C , in order to further improve the ESD resistance of the first resistive layer 220 , the second protruding structures 221 provided in all regions on both sides of the first resistive layer 220 are continuously provided , that is to say, the second protruding structures 221 are continuously arranged on both sides of the first resistance layer 220 to further increase the cross-sectional area of the first resistance layer 220 , improve the ESD resistance performance of the first resistance layer 220 , and further improve the buried The anti-static breakdown capability of the input resistor.

Further, if the roughness height parameter Rz of the second protruding structure 221 is set too high, the second protruding structure 221 may be easily broken by external force during application, thereby affecting the ESD resistance performance of the first resistive layer 220 . Therefore, the range of the roughness Rz of the first resistance layer 220 is set to be 0.1 μm-10 μm, and the range of the roughness Sdr of the first resistance layer 220 is set to be greater than or equal to 20%. By defining the roughness height parameter Rz of the first resistive layer 220 to be 0.1 μm-10 μm and the range of the surface area increase parameter Sdr relative to the defined area area to be ≥ 20%, within a certain height range of the second protruding structure 221 , continuous and closely arranged second raised structures 221 are obtained in all areas on both sides of the first resistive layer 220 (the continuous and closely arranged raised structures in the whole area are similar to the "fuzz" structure), so that the height of the roughness When the parameter Rz is constant, that is to say, it is ensured that the second protruding structure 221 will not be broken due to external force, the first resistance layer 220 with a larger cross section is obtained, and the first resistance layer 220 is further improved. Excellent ESD resistance, effectively ensuring that the embedded resistor has a strong anti-static breakdown capability.

Optionally, the range of the roughness Rz of the first resistance layer 220 is 0.1 μm-10 μm, and the range of the roughness Sdr of the first resistance layer 220 is greater than or equal to 50%. By defining the roughness height parameter Rz of the first resistive layer 220 to be 0.1 μm-10 μm and the range of the surface area increase parameter Sdr relative to the defined area area to be ≥50%, within a certain height range of the second protruding structure 221 , continuous and more closely arranged second raised structures 221 are obtained in all areas on both sides of the first resistance layer 220, that is, to obtain a more closely arranged raised structure than the range of the roughness Sdr ≥ 20%, thereby The cross section of the first resistance layer is further increased, the ESD resistance performance of the first resistance layer is further improved, and the embedded resistance is effectively ensured to have a strong anti-static breakdown capability.

Optionally, the range of the roughness Rz of the first resistance layer 220 is 0.1 μm-10 μm, and the range of the roughness Sdr of the first resistance layer 220 is greater than or equal to 200%, thereby further increasing the roughness of the first resistance layer. The cross section further improves the ESD resistance of the first resistive layer, effectively ensuring that the embedded resistor has excellent anti-static breakdown capability.

The material of the dielectric layer 210 can be resin glue, polyimide (PI), modified polyimide, glass fiber cloth, glass fiber cloth composite material, paper substrate, composite substrate, HDI board, modified epoxy resin, Modified acrylic resin, polyethylene terephthalate, glycol ester, polybutylene terephthalate, polyethylene, etc. are used to protect the first resistance layer 220 and prevent the first resistance layer 220 from being subjected to external forces and damage.

In some embodiments of the present application, all areas of the dielectric layer 210 are provided with fillers, so that all areas on both sides of the dielectric layer 210 have the first protruding structures 211 . The dielectric layer 210 is far away from the first protruding structure 211 on the first resistance layer 220, which makes the surface rougher. stripped.

FIG. 3 is a schematic structural diagram of another composite metal foil provided by an embodiment of the present application. As shown in FIG. 3 , in this embodiment, the composite metal foil includes a dielectric layer 310 , a first resistance layer 320 and a first conductive layer 330 .

Specifically, the dielectric layer 310 may be an insulating base layer for carrying the first resistance layer 320 . The first resistance layer 320 is a key functional layer of the composite metal foil, and is used to realize the resistance function of the composite metal foil. The material of the first resistance layer 320 may include at least one elemental metal among nickel, chromium, platinum, palladium, and titanium, and/or at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. alloy. For example, nickel-chromium alloy (NiCr) or nickel-phosphorus alloy (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 320 is a nickel-chromium alloy. In some embodiments of the present application, the first resistance layer 320 may have a single-layer structure or at least a two-layer structure. Exemplarily, the single-layer structure may be a single-layer structure composed of any one of nickel, chromium, platinum, palladium, and titanium, or may be at least one of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. A single-layer structure composed of two combined alloys. Any layer in the at least two-layer structure can be any one of nickel, chromium, platinum, palladium, titanium to form an elemental metal, or it can be at least one of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. Two alloys in combination. The first conductive layer 330 has good electrical conductivity, and the material of the metal layer can be gold, silver, copper or aluminum, or an alloy of at least two of them.

The first resistance layer is formed on one side of the dielectric layer, and the entire area of the side of the dielectric layer close to the first resistance layer is provided with the first protruding structure. Exemplarily, the entire region of one side of the dielectric layer 310 close to the first resistive layer 320 is provided with the continuous first protruding structures 311 , so that the dielectric layer 310 has a continuous undulating surface, so that the first resistive layer 320 is formed. The entire regions on both sides of the first resistive layer 320 are formed with continuous second protruding structures 321 , and the continuous second protruding structures 321 make the first resistance layer 320 form a continuous undulating structure.

Specifically, the range of the roughness Rz on both sides of the first resistance layer 320 is greater than or equal to 0.1 μm, and the range of 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 on both sides of the first resistance layer 320 may be the same or different, and the roughness Sdr on both sides of the first resistance layer 320 may be the same or different, The embodiments of the present application are not limited herein. Optionally, the roughness Rz on both sides of the first resistance layer 320 ranges from 0.1 μm to 30 μm, including 0.1 μm and 30 μm, and the value of the roughness Rz on both sides of the first resistance layer 320 can also be 1 μm, 5 μm, 8μm, 9μm, 10μm, 15μm, 20μm, etc. The range of roughness Sdr is 0.5%-8000%, including 0.5% and 8000%, and the value of 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.

The material of the dielectric layer 310 can be resin glue, polyimide (PI), modified polyimide, glass fiber cloth, glass fiber cloth composite material, paper substrate, composite substrate, HDI board, modified epoxy resin, Modified acrylic resin, polyethylene terephthalate, glycol ester, polybutylene terephthalate, polyethylene, etc. are used to protect the first resistance layer 320 and prevent the first resistance layer 320 from being subjected to external forces and damage.

In some embodiments of the present application, all areas of the dielectric layer 310 are provided with fillers, so that all areas on both sides of the dielectric layer 310 have the first protruding structures 311 . The dielectric layer 310 is far away from the first protruding structure 311 on the first resistance layer 320 to make the surface rougher. stripped.

Further, a second resistance layer and a second conductive layer are provided on the side of the dielectric layer away from the first resistance layer, and the second resistance layer is 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, and 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 resistance layer may be the same as those of the first resistance layer, and the structure and parameters of the second conductive layer may be the same as those of the first conductive layer, which will not be repeated here. .

4A is a schematic structural diagram of another composite metal foil provided by an embodiment of the present application, and FIG. 4B is a schematic structural schematic diagram of another composite metal foil provided by an embodiment of the present application. As shown in FIGS. 4A and 4B , the composite metal foil It includes a dielectric layer 410 , a first resistance layer 420 , a first conductive layer 430 , a second resistance layer 440 and a second conductive layer 450 . The first resistive layer 420 is formed on one side of the dielectric layer 410, and the entire area of the dielectric layer 410 on the side close to the first resistive layer 420 is provided with the first protruding structure 411, so that the dielectric layer 410 has a concave-convex surface, so that the formed Two sides of the first resistive layer 420 are compliantly formed with second protruding structures 421 . The materials of the first conductive layer, the first resistive layer and the dielectric layer, the shape of the second raised structure, and the roughness on both sides of the first resistive layer have been described in detail in the foregoing embodiments, and will not be repeated in this embodiment of the present application. Repeat.

The second resistance layer 440 is disposed on the side of the dielectric layer 410 away from the first resistance layer 420 , and the second conductive layer 450 is disposed on the side of the second resistance layer 440 away from the dielectric layer 410 . In a specific embodiment of the present application, the materials and uses of the second resistive layer 420 and the first resistive layer 440 are the same. Likewise, the materials and uses of the second conductive layer 450 and the first conductive layer 410 are the same.

One or both sides of the second resistive layer 440 may be a flat surface, or, similar to the first resistive layer 420 , at least a partial area is provided with a protruding structure. Exemplarily, as shown in FIG. 4A , the side of the second resistive layer 440 away from the dielectric layer 410 is provided with a protruding structure; as shown in FIG. 4B , all areas on both sides of the second resistive layer 440 are provided with a protruding structure. For the protrusion structure, reference may be made to the protrusion structure on the first resistive layer 420 described in the foregoing embodiments of the present application, which will not be repeated in the embodiments of the present application.

FIG. 5A is a flowchart of a method for preparing a composite metal foil provided by an embodiment of the present application. As shown in FIG. 5A , the method includes:

S501. Provide a dielectric layer.

Specifically, the dielectric layer can be resin glue, polyimide (PI), modified polyimide, glass fiber cloth, glass fiber cloth composite material, paper substrate, composite substrate, HDI sheet, modified epoxy resin, Modified acrylic resin, polyethylene terephthalate, glycol ester, polybutylene terephthalate, polyethylene, etc.

S502 , forming a first protruding structure on at least a partial area of one side of the dielectric layer.

Specifically, the first protruding structure may be formed on at least a partial region of one side of the dielectric layer by means of physical grinding, chemical etching, shot blasting, and sand blasting. FIG. 5B is a schematic diagram of forming a first protruding structure on one side of the dielectric layer according to an embodiment of the present application. As shown in FIG. 5B , a first protruding structure 511 is formed on the entire area of one side of the dielectric layer 510 . The shape of the first protruding structure may be diverse according to actual needs, and may be a regular or irregular three-dimensional geometric shape, which is not limited in this embodiment of the present application.

Specifically, in another embodiment of the present application, fillers may be provided in all areas of the dielectric layer 510 , so that all areas on both sides of the dielectric layer 510 have the first protruding structures 511 . The dielectric layer 510 is far away from the first protruding structure 511 on the first resistance layer 520 to make the surface rougher. stripped.

S503 , forming a first resistance layer on the side where the first protrusion structure is formed on the dielectric layer.

Specifically, the first resistance layer can be formed on the dielectric layer to form the side of the first convex structure by means of physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating, and hybrid plating. The first resistance layer is the key functional layer of the composite metal foil, and is used to realize 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, and titanium, and/or a combination of at least two of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum. alloy. For example, nickel-chromium alloy (NiCr) or nickel-phosphorus alloy (NiP) with low resistivity may also be chromium-silicon alloy (CrSi) with high resistivity, which is not limited in this embodiment of the present application. In some embodiments of the present application, the first resistance layer may 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 of at least two combinations of nickel, chromium, platinum, palladium, titanium, silicon, phosphorus, and aluminum.

5C is a schematic diagram of forming a first resistance layer on a dielectric layer according to an embodiment of the present application. As shown in FIG. 5C , the first resistance layer 520 is formed on the side of the dielectric layer 510 where the first protrusion structures 511 are formed. Since the entire area of one side of the dielectric layer 510 forms the first protruding structures 511 , the second protruding structures 521 are formed on both sides of the first resistance layer formed on the side. The shape of the second protruding structure may be diverse according to actual needs, and may be a regular or irregular three-dimensional geometric shape, which is not limited in this embodiment of the present application. In some examples, the second protruding structure may form a continuous undulating surface on both sides of the first resistive layer, or may form a relatively regular sinusoidal shape on both sides of the first resistive layer, or the second protruding structure may The shape is one or more of sharp angle, inverted cone, granular, dendritic, columnar, block, and arc, or the second protruding structure makes the first resistive layer form a continuous undulating structure.

Specifically, the range of the roughness Rz on both sides of the first resistance layer 520 is greater than or equal to 0.1 μm, and the range of 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 on both sides of the first resistance layer 420 may be the same or different, and the roughness Sdr on both sides of the first resistance layer 420 may be the same or different, The embodiments of the present application are not limited herein. Optionally, the roughness Rz on 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 on both sides of the first resistance layer 520 can also be 1 μm, 5 μm, 8μm, 9μm, 10μm, 15μm, 20μm, etc. The range of roughness Sdr is 0.5%-8000%, including 0.5% and 8000%, and the value of 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.

S504 , forming a first conductive layer on the side of the first resistance layer away from the dielectric layer.

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

5D is a schematic diagram of forming a first conductive layer on the first resistance layer according to an embodiment of the present application. As shown in FIG. 5D , the first conductive layer 530 is formed on the side of the first resistance layer 520 away from the dielectric layer 510 .

Further, a second resistance layer and a second conductive layer are disposed on the side of the dielectric layer away from the first resistance layer, and the second resistance layer is 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, and similarly, the materials and uses of the second conductive layer and the first conductive layer can be the same or different.

The method for preparing a composite metal foil provided by an embodiment of the present application includes: providing a dielectric layer, forming a first protruding structure on at least a part of one side of the dielectric layer, and forming a side with the first protruding structure on the dielectric layer A first resistance layer is formed, and a first conductive layer is formed on the side of the first resistance layer away from the dielectric layer. Through the above method, a plurality of second protruding structures are formed on both sides of the first resistance layer. The existence of the second protruding structure increases the cross-sectional area of the first resistive layer, improves the current carrying capacity and ESD resistance performance of the first resistive layer, and further improves the product performance of the embedded resistor.

The embodiments of the present application further provide a circuit board, including the composite metal foil provided by any of the above embodiments of the present application.

The circuit boards provided in the embodiments of the present application have functions and beneficial effects corresponding to the composite metal foils provided in the embodiments of the present application.

In the description herein, it should be understood that the terms "upper", "lower", "left", "right", etc. are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of description and Operation is simplified, rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the application.

In the description of this specification, reference to the description of the terms "an embodiment", "example", etc. means 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 present application middle. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example.

In addition, it should be understood that although this specification is described in terms of embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole , the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

The technical principles of the present application have been described above with reference to specific embodiments. These descriptions are only for explaining the principle of the present application, and should not be construed as limiting the protection scope of the present application in any way.

Claims (16)

1. A composite metal foil, comprising: a dielectric layer, a first resistance layer and a first conductive layer;

   the first resistance layer is arranged on one side of the dielectric layer;

   At least part of the area of the side of the dielectric layer close to the first resistance layer is provided with a first protruding structure, so that the side of the first resistance layer close to the dielectric layer and a side away from the dielectric layer are provided. At least part of the area of the side is formed with a second protruding structure;

   The first conductive layer is disposed on a side of the first resistance layer away from the dielectric layer.
2. The composite metal foil according to claim 1, wherein at least a part of the region of the side of the dielectric layer away from the first resistance layer is provided with a first protruding structure.
3. The composite metal foil according to claim 1, wherein at least a partial area of the dielectric layer is provided with fillers, so that at least partial areas on both sides of the dielectric layer have a first protruding structure.
4. The composite metal foil according to claim 1 , wherein the roughness Rz of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both in the range of 0.1 μm-30 μm.
5. The composite metal foil according to claim 1, wherein the range of the roughness Sdr of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer is greater than or equal to 0.5%.
6. The composite metal foil according to claim 1, wherein the entire area of the side of the dielectric layer close to the first resistive layer is provided with a first protruding structure, so that the first resistive layer is close to the dielectric A second protruding structure is formed on all areas of one side of the layer and the side away from the dielectric layer.
7. The composite metal foil according to claim 1, wherein a plurality of continuous first protruding structures are provided on at least part of the area of the side of the dielectric layer close to the first resistance layer, so that the first resistance A plurality of continuous raised structures are formed in at least partial regions of a side of the layer close to the dielectric layer and a side away from the dielectric layer.
8. The composite metal foil according to claim 7, wherein a plurality of continuous first protruding structures are provided in the whole area of the side of the dielectric layer close to the first resistance layer, so that the first resistance layer A plurality of continuous protruding structures are formed in all regions of the side close to the dielectric layer and the side away from the dielectric layer.
9. The composite metal foil according to claim 7, wherein all regions of the first resistive layer on the side close to the dielectric layer and the side far from the dielectric layer form continuous second protruding structures, so as to form continuous second raised structures. The first resistive layer is formed into a continuous undulating structure.
10. The composite metal foil according to any one of claims 1-9, wherein the range of roughness Rz of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both 0.1 μm -10 μm, the ranges of the roughness Sdr of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both greater than or equal to 20%.
11. The composite metal foil according to any one of claims 1-9, wherein the range of roughness Rz of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both 0.1 μm -10 μm, the ranges of the roughness Sdr of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both greater than or equal to 50%.
12. The composite metal foil according to any one of claims 1-9, wherein the range of roughness Rz of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both 0.1 μm -10 μm, the ranges of the roughness Sdr of the side close to the dielectric layer and the side far from the dielectric layer of the first resistance layer are both greater than or equal to 200%.
13. The composite metal foil according to any one of claims 1-9, wherein a second resistance layer and a second conductive layer are provided on the side of the dielectric layer away from the first resistance layer, and the second resistance layer is located on the side of the dielectric layer away from the first resistance layer. between the dielectric layer and the second conductive layer.
14. The composite metal foil according to any one of claims 1-9, wherein the material of the first resistance layer comprises at least one elemental metal selected from nickel, chromium, platinum, palladium, and titanium, and/or comprises nickel, chromium , platinum, palladium, titanium, silicon, phosphorus, aluminum alloys of at least two combinations.
15. The composite metal foil according to claim 14, wherein the first resistance layer has a single-layer structure or at least two-layer structure.
16. A circuit board comprising the composite metal foil according to any one of claims 1-15.

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