CN111031663B - Copper foil substrate - Google Patents

Abstract

The invention discloses a micro-rough electrolytic copper foil and a copper foil substrate. The micro-roughened electrolytic copper foil includes a micro-roughened surface. The micro-rough surface is provided with a plurality of convex peaks, a plurality of grooves and a plurality of micro-crystal clusters. The grooves have a U-shaped cross-sectional profile and/or a V-shaped cross-sectional profile, the grooves having an average width of 0.1 to 4 microns and an average depth of less than or equal to 1.5 microns. The microcrystalline clusters are located at the top of the convex peak. Each microcrystal cluster is composed of a plurality of microcrystal stacks having an average diameter of less than or equal to 0.5 microns. The microroughened surface of the microroughened electrolytic copper foil has an Rlr value of less than 1.3. The micro-rough surface and the substrate have good bonding force and good insertion loss, and can effectively inhibit signal loss.

Description

Copper foil substrate

technical field

The invention relates to a copper foil, in particular to an electrolytic copper foil and a copper foil substrate with the copper foil.

Background technique

With the development of information and electronics industry, high-frequency and high-speed signal transmission has become a part of modern circuit design and manufacture. In order to meet the high-frequency and high-speed signal transmission requirements of electronic products, the copper foil substrate used must have good insertion loss performance at high frequencies to prevent excessive loss during high-frequency signal transmission. The insertion loss of copper clad substrate is highly related to its surface roughness. When the surface roughness is reduced, the insertion loss has a better performance, and vice versa. However, while reducing the roughness, it will also lead to a decrease in the peel strength between the copper foil and the substrate, which will affect the yield of the back-end products. Therefore, how to maintain the peel strength at the industry level and provide good insertion loss performance has become a problem to be solved in this field.

Contents of the invention

The technical problem to be solved by the present invention is to provide a micro-rough electrolytic copper foil for the deficiencies of the prior art.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a micro-roughened electrolytic copper foil. The micro-rough electrolytic copper foil includes a micro-rough surface. The micro-rough surface has a plurality of convex peaks, a plurality of grooves and a plurality of microcrystalline clusters. The groove has a U-shaped cross-sectional profile and/or a V-shaped cross-sectional profile, the average width of the groove is between 0.1 and 4 microns, and the average depth of the groove is less than or equal to 1.5 microns. The microcrystalline clusters are located on top of the convex peaks. Each microcrystalline cluster is composed of a plurality of microcrystalline stacks with an average diameter less than or equal to 0.5 microns. The Rlr value of the micro-rough surface of the micro-rough electrolytic copper foil is lower than 1.3.

Preferably, each microcrystal cluster is composed of a plurality of microcrystal stacks, the average diameter of the microcrystals is less than or equal to 0.5 microns, and the average height of each microcrystal cluster is less than or equal to 2 microns.

Preferably, each microcrystal cluster is composed of a plurality of microcrystal stacks, the average diameter of the microcrystals is less than or equal to 0.5 microns, and the average height of each microcrystal cluster is less than or equal to 1.3 microns. A plurality of microcrystals form a branched crystal group.

Preferably, the Rlr value of the micro-rough surface of the micro-rough electrolytic copper foil is lower than 1.26.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a copper foil substrate, which includes a base material and a micro-rough electrolytic copper foil. The micro-rough electrolytic copper foil includes a micro-rough surface attached to the substrate, the micro-rough surface is formed with a plurality of convex peaks, a plurality of grooves and a plurality of micro-crystal clusters, the average of the grooves The width is between 0.1 and 4 microns, the average depth of the grooves is less than or equal to 1.5 microns, the microcrystalline clusters are located on the top of the convex peaks, and the average height of the microcrystalline clusters is less than or equal to 2 microns. The insertion loss of the copper foil substrate at 20 GHz is between 0 and -1.5 db/in. The peeling strength between the microrough electrolytic copper foil and the substrate is greater than 4.3 lb/in.

Preferably, the insertion loss of the copper foil substrate at 16 GHz is between 0 and -1.2 db/in.

Preferably, the insertion loss of the copper foil substrate at 8 GHz is between 0 and -0.65 db/in, and the insertion loss of the copper foil substrate at 12.89 GHz is between 0 and -1.0 db/in.

Preferably, the insertion loss of the copper foil substrate at 8GHz is between 0 and -0.63db/in, and the insertion loss of the copper foil substrate at 12.89GHz is between 0 and -0.97db/in. The insertion loss at 16GHz is between 0 and -1.15db/in, and the insertion loss of the copper foil substrate at 20GHz is between 0 and -1.45db/in.

Preferably, the average maximum width of the microcrystalline clusters is less than or equal to 5 microns; part of the microcrystalline clusters form a bifurcated structure; the average height of each of the microcrystalline clusters is less than or equal to 1.8 microns; each The microcrystal cluster is composed of multiple microcrystal stacks, and the average diameter of the microcrystals is less than or equal to 0.5 microns; the Rlr value of the microrough surface of the microrough electrolytic copper foil is lower than 1.26.

Preferably, the Dk value of the substrate at a frequency of 10 GHz is less than or equal to 4 and the Df value at a frequency of 10 GHz is less than or equal to 0.020, more preferably, the Dk value of the substrate 11 at a frequency of 10 GHz is less than or equal to Equal to 3.8 and the Df value at 10GHz frequency is less than or equal to 0.015.

One of the beneficial effects of the present invention is that the micro-rough surface has good bonding force with the base material, and has good performance of insertion loss, which can effectively suppress loss during signal transmission.

In order to further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings related to the present invention. However, the provided drawings are only for reference and description, and are not intended to limit the present invention.

Description of drawings

FIG. 1 is a schematic side view illustrating one embodiment of the copper foil substrate of the present invention.

FIG. 2 is an enlarged schematic view of part II of FIG. 1 .

Fig. 3 is a schematic diagram illustrating production equipment for micro-roughened electrolytic copper foil.

FIG. 4 is a scanning electron microscope image illustrating the surface morphology of the micro-roughened electrolytic copper foil of Example 1. FIG.

FIG. 5 is a scanning electron microscope image illustrating the cross-sectional shape of the micro-roughened electrolytic copper foil of Example 1. FIG.

FIG. 6 is a scanning electron microscope image illustrating the surface morphology of the copper foil of Comparative Example 3. FIG.

FIG. 7 is a scanning electron micrograph illustrating the cross-sectional shape of the copper foil of Comparative Example 3. FIG.

Detailed ways

The following are specific examples to illustrate the implementation of the "micro-roughened electrolytic copper foil and copper foil substrate" disclosed in the present invention. Those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can be implemented or applied through other different specific embodiments, and various modifications and changes can be made to the details in this specification based on different viewpoints and applications without departing from the concept of the present invention. In addition, the drawings of the present invention are only for simple illustration, and are not drawn according to the actual size, which is stated in advance. The following embodiments will further describe the relevant technical content of the present invention in detail, but the disclosed content is not intended to limit the protection scope of the present invention.

Referring to FIG. 1 , the copper foil substrate 1 of the present invention includes a substrate 11 and two pieces of micro-roughened electrolytic copper foil 12 . Micro-rough electrolytic copper foils 12 are bonded to opposite sides of the base material 11, respectively. It is worth mentioning that the copper foil substrate 1 may also only include one piece of micro-roughened electrolytic copper foil 12 .

The substrate 11 preferably has a low Dk value and a low Df value to suppress insertion loss. Preferably, the Dk value of the substrate 11 at a frequency of 10 GHz is less than or equal to 4 and the Df value at a frequency of 10 GHz is less than or equal to 0.020, more preferably, the Dk value of the substrate 11 at a frequency of 10 GHz is less than or equal to Or equal to 3.8 and the Df value at 10GHz frequency is less than or equal to 0.015.

The base material 11 can be a composite material obtained by impregnating a prepreg sheet with a synthetic resin and then curing it. The prepreg sheet may, for example, be phenolic tissue paper, tissue paper, resin fiber cloth, resin fiber nonwoven fabric, glass plate, glass woven fabric, or glass nonwoven fabric. The synthetic resin may, for example, be epoxy resin, polyester resin, polyimide resin, cyanate resin, bismaleimide triazine resin, polyphenylene ether resin, or phenol resin. The synthetic resin layer may be a single layer or a multilayer without limitation. The substrate 11 can be selected from but not limited to EM891, IT958G, IT150DA, S7439G, MEGTRON 4, MEGTRON 6, or MEGTRON 7.

Referring to FIG. 1 and FIG. 2 , the micro-rough electrolytic copper foil 12 is obtained by roughening the surface of the copper foil by electrolysis. Electrolytic roughening can be performed on any surface of the copper foil. Therefore, the micro-rough electrolytic copper foil 12 has a micro-rough surface 121 on at least one side. In one embodiment of the present invention, reverse treated copper foil (Reverse Treated copper foil, RTF) is used as the raw foil, and then the glossy surface thereof is further roughened to obtain the micro-roughened electrolytic copper foil 12 .

The micro-rough surface 121 is used for attaching to the substrate 11 , and includes a plurality of peaks 122 , a plurality of grooves 123 and a plurality of microcrystalline clusters 124 . Two adjacent peaks 122 define a groove 123 . The groove 123 has a U-shaped profile and/or a V-shaped profile, and the average depth of the groove 123 is less than or equal to 1.5 microns, preferably less than or equal to 1.3 microns, more preferably less than or equal to 1 micron. The average width of the groove 123 ranges from 0.1 to 4 microns.

The average height of the microcrystalline clusters 124 is less than or equal to 2 microns, preferably less than or equal to 1.8 microns, more preferably less than or equal to 1.6 microns. The aforementioned average height refers to the distance from the top of the microcrystalline cluster 124 to the top of the convex peak 122 . The average maximum width of the microcrystalline clusters 124 is less than or equal to 5 microns, preferably less than or equal to 3 microns. Each microcrystal cluster 124 is composed of a plurality of microcrystals 125 stacked, and the average diameter of the microcrystals 125 is less than or equal to 0.5 microns, preferably between 0.05 to 0.5 microns, more preferably between 0.1 to 0.4 microns. The average number of stacked microcrystals 125 in each microcrystal cluster 124 along its own height direction is less than 15, preferably less than 13, more preferably less than 10, and more preferably less than 8. When the microcrystals 125 are stacked to form a microcrystal cluster 124 , they can form a tower-like structure, or extend outward to form a branched structure, forming a branched crystal cluster M.

The arrangement of the microcrystalline clusters 124 is not fixed, it can be arranged in a disordered manner, or roughly arranged in the same direction, or several microcrystalline clusters 124 are arranged in a row and the extension direction of each row is partially same.

The average height of the micro-rough surface 121 of the micro-rough electrolytic copper foil 12 is preferably greater than 0.5 microns, more preferably greater than 1.5 microns, and more preferably greater than 2.0 microns. When the average roughness Rz of the micro-rough surface 121 meets the aforementioned range, there will be good bonding performance with the substrate 11, that is, when the average roughness Rz is increased, the bonding with the substrate 11 can be effectively improved. Force, so that the peel strength (Peel strength) is effectively improved. Preferably, for a 1oz copper foil substrate 1, the peel strength between the slightly rough electrolytic copper foil 12 and the substrate 11 is greater than 4.3lb/in, preferably greater than 4.5lb/in, more preferably greater than 4.7lb /in. Since the adhesive coated on the micro-rough surface will penetrate into the bottom of the groove 123 and the micro-crystal clusters 124 when bonding to the substrate 11 , the peeling strength can be effectively improved after bonding to the substrate 11 .

Through the shape of the aforementioned micro-rough surface 121 , the micro-rough electrodeposited copper foil 12 and the substrate 11 can have sufficient peel strength, and can effectively suppress loss during signal transmission. The Rlr value of the micro-rough surface 121 is lower than 1.3, preferably lower than 1.26, more preferably lower than 1.23, and more preferably lower than 1.2. The Rlr value refers to the ratio of the unfolded length, that is, the ratio of the length of the surface profile of the object to be measured in a unit length. A higher value means a more rugged surface, and a value equal to 1 means it is completely flat. Rlr satisfies the relationship Rlr=Rlo/L. Among them, Rlo refers to the measured profile length, and L refers to the measured distance.

When the Rlr value of the micro-rough electrolytic copper foil 12 is lower than 1.3, the copper foil substrate 1 (such as IT170GRA1+RG311) will have a better insertion loss performance. The insertion loss of the copper foil substrate 1 at 8GHz is between 0 and -0.65db/in, more preferably between 0 and -0.63db/in, more preferably between 0 and -0.60db/in, and even more preferably It is between 0 and -0.57db/in. The insertion loss of the copper foil substrate 1 at 12.89GHz is between 0 and -1.0db/in, preferably between 0 and -0.97db/in, more preferably between 0 and -0.94db/in, and more preferably Ground is between 0 to -0.90db/in. The insertion loss of the copper foil substrate 1 at 16 GHz is between 0 and -1.2 db/in, more preferably between 0 and -1.15 db/in, and more preferably between 0 and -1.1 db/in. The insertion loss of the copper foil substrate 1 at 20GHz is between 0 and -1.5db/in, preferably between 0 and -1.45db/in, more preferably between 0 and -1.4db/in, and more preferably It is between 0 and -1.36db/in, more preferably between 0 and -1.34db/in. The micro-rough electrolytic copper foil 12 of the present invention can effectively suppress the loss during signal transmission when the frequency ranges from 4 GHz to 20 GHz.

[Manufacturing method of micro-rough electrolytic copper foil]

Micro-roughened electrolytic copper foil 12 is subjected to electrolytic roughening treatment for a certain period of time after immersing the raw foil in a copper-containing plating solution. In an embodiment of the present invention, a reversed copper foil (RTF) is used as a raw foil, and the rough surface thereof is electrolytically roughened. The electrolytic roughening treatment can be carried out using any well-known equipment, for example: continuous electrolysis equipment, or batch type electrolysis equipment.

Copper-containing baths contain copper ions, acids, and metal additives. The source of copper ions may, for example, be copper sulfate, copper nitrate, or a combination thereof. The acid may, for example, be sulfuric acid, nitric acid, or a combination thereof. Metal additives may, for example, be cobalt, iron, zinc, or a combination thereof. In addition, the copper-containing plating solution can further add well-known additives, such as: gelatin, organic nitrogen compounds, hydroxyethyl cellulose (hydroxyethyl cellulose; HEC), polyethylene glycol (Poly(ethylene glycol), PEG), 3- Sodium 3-mercaptopropanesulphonate (MPS), sodium polydisulfide dipropane sulfonate (Bis-(sodium sulfopropyl)-disulfide, SPS), or thiourea compounds, but not as such limit.

The number of roughening treatments is at least two times, and the composition of the copper-containing plating solution in each roughening treatment may be the same or different. In one embodiment of the present invention, two sets of copper-containing plating solutions are used to alternately carry out the roughening treatment, and the copper ion concentration of the first set of copper-containing plating solutions is preferably between 10 and 30 g/l, and the acid concentration is relatively low. Preferably it is between 70 and 100 g/l, and the metal additive is preferably added in an amount of 150 to 300 mg/l. The copper ion concentration of the second group of copper-containing plating solutions is preferably between 70 and 100 g/l, the acid concentration is preferably between 30 and 60 g/l, and the addition amount of metal additives is preferably between 15 and 100 mg/l .

The power supply method of electrolysis can adopt constant voltage, constant current, pulse waveform, or saw waveform, but not limited thereto. In one embodiment of the present invention, the roughening treatment is firstly treated with the first group of copper-containing plating solutions at a constant current of 25 to 40A/dm ² , and then the second group of copper-containing plating solutions is used at a constant current to constant Current 20 to 30A/dm ² for treatment. Preferably, the first group of copper-containing plating solutions is treated with a constant current of 30 to 56 A/dm ² , while the second group of copper-containing plating solutions is treated with a constant current of 23 to 26 A/dm ² . It should be noted that the aforesaid constant current can also be supplied with pulse waveform or saw waveform. In addition, if a constant voltage is to be used for power supply, it must be ensured that the voltage value applied in each roughening treatment stage makes the current value fall within the aforementioned range.

When the number of roughening treatments is more than three times, the aforementioned first group and second group of copper-containing plating solutions can be used alternately for roughening treatment. The current value is controlled between 1 and 60A/dm ² . In one embodiment of the present invention, the third and fourth roughening treatments use the first group of copper-containing plating solutions and the second group of copper-containing plating solutions respectively, and the current values are respectively controlled at 1 to 8A/dm ² and 40 to 60A/dm ² . The current value of the roughening treatment after the fifth time is controlled to be less than or equal to 5A/dm ² . It should be noted that the aforesaid constant current can also be supplied with pulse waveform or saw waveform. In addition, if a constant voltage is to be used for power supply, it must be ensured that the voltage value applied in each roughening process makes the current value fall within the aforementioned range.

It is worth mentioning that the arrangement of microcrystalline clusters 124 on the micro-rough surface 121 and the direction of extension of the grooves 123 can be controlled through the flow field of the copper-containing plating solution. When the flow field is not applied or turbulent flow is formed, the microcrystalline clusters 124 can be arranged in disorder; and when the flow field is controlled so that it flows in a specific direction on the surface of the copper foil, it will form roughly along the same direction. arrangement of structures. However, the method of controlling the arrangement of the microcrystalline clusters 124 and the extending direction of the grooves 123 is not limited thereto. It is also possible to use a steel brush to carve scratches in advance to form non-directional grooves 123, and the manufacturer can use any well-known method Make adjustments.

In one of the preferred embodiments of the present invention, a continuous electrolytic device with multiple grooves and multiple electrolytic rollers is used for roughening treatment. Wherein, the first group of copper-containing plating solutions and the second group of copper-containing plating solutions are alternately accommodated in each tank. The power supply method adopts constant current. The production speed is controlled at 5 to 20m/min. The production temperature is controlled at 20 to 60°C.

It should be noted that the aforementioned micro-roughened electrolytic copper foil manufacturing method can also be used to process high temperature elongated copper foil (High Temperature Elongation, HTE) or very low roughness copper foil (Very Low Profile, VLP).

The layer structure and manufacturing method of the copper clad substrate 1 have been described above, and examples 1 to 3 will be taken as examples below, and compared with comparative examples 1 to 4 to illustrate the advantages of the present invention.

[Example 1]

Referring to FIG. 3 , the micro-rough electrolytic copper foil is roughened by continuous electrolytic equipment 2 . The continuous electrolysis equipment 2 comprises a feeding roller 21, a collecting roller 22, six grooves 23 between the feeding roller 21 and the collecting roller 22, six electrolytic roller groups 24 placed respectively above the groove 23, And six auxiliary roller groups 25 respectively located in the grooves 23. A set of platinum electrodes 231 is disposed in each groove 23 . Each electrolytic roller set 24 includes two electrolytic rollers 241 . Each auxiliary roller set 25 includes two auxiliary rollers 251 . The platinum electrode 231 in each tank 23 and the corresponding electrolytic roller set 24 are respectively electrically connected to the anode and cathode of the external power supply.

In this embodiment 1, reversed copper foil (RTF) was used as the raw foil, which was purchased from Jinju Development Co., Ltd. (model RG311). The raw foil is wound on the feeding roller 21 , then wound around the electrolysis roller group 24 and the auxiliary roller group 25 in sequence, and then wound on the collecting roller 22 . The copper-containing plating solution components and electroplating conditions in each tank 23 are shown in Table 1, wherein the source of copper ions is copper sulfate. The extremely low roughness copper foil roughens the rough surface of the raw foil sequentially from the first slot to the sixth slot. The production speed is 10m/min, and finally the roughness Rz (JIS94) is less than or equal to 2.5um. Micro-rough electrolytic copper foil. Then, take two pieces of micro-rough electrolytic copper foil and one piece of base material IT170GRA1 and stick them together to complete the production.

In Example 1, the surface and cross-sectional structure were observed with a scanning electron microscope, which are shown in FIG. 4 and FIG. 5 respectively.

In Example 1, the peel strength of micro-rough electrolytic copper foil is firstly coated with copper silane coupling agent on the micro-rough surface and bonded to the substrate IT170GRA1 for curing, and then measured according to IPC-TM-650 4.6.8 test method . The test results are listed in Table 2.

The Rlr value of the microrough electrolytic copper foil in Example 1 is measured by a shape measuring laser microscope (manufacturer: Keyence, model: VK-X100). The test results are listed in Table 2.

In Example 1, the insertion loss of the micro-rough electrolytic copper foil was tested using the method of Micro-strip line (characteristic impedance 50Ω), and the detection was performed at frequencies of 4GHz, 8GHz, 12.89GHz, 16GHz, and 20GHz respectively. The test results are listed in Table 2.

[Example 2 and 3]

Raw foil, electrolytic equipment and copper-containing plating solution components are the same as in Example 1, the electroplating conditions are as shown in Table 1, and the production speed is 10m/min. Then, take two pieces of micro-rough electrolytic copper foil and one piece of base material IT170GRA1 and stick them together to complete the production. The measurement method is the same as in Example 1, and the test results are listed in Table 2.

[Comparative Examples 1 and 2]

Raw foil, electrolytic equipment and copper-containing plating solution components are the same as in Example 1, the electroplating conditions are as shown in Table 1, and the production speed is 10m/min. Then, take two pieces of micro-rough electrolytic copper foil and one piece of base material IT170GRA1 and stick them together to complete the production. The measurement method is the same as in Example 1, and the test results are listed in Table 2.

[Comparative example 3]

The inverted copper foil produced by Mitsui Metals (model: MLS-G, hereinafter referred to as MLS-G copper foil) was used to observe its surface and cross-sectional structure with a scanning electron microscope, which are shown in Figure 6 and Figure 7 respectively. After laminating two pieces of MLS-G copper foil to one IT170GRA1 substrate, measure its peel strength, Rlr, and insertion loss. The test results are listed in Table 2.

[Comparative example 4]

The reversed copper foil (model: RTF3, hereinafter referred to as RTF3 copper foil) produced by Changchun Group was used to observe its surface and cross-sectional structure with a scanning electron microscope. After laminating two pieces of RTF3 copper foil and one piece of substrate IT170GRA1, the peel strength, Rlr, and insertion loss were measured. The test results are listed in Table 2.

Table 1

Table 2

Referring to FIG. 4 and FIG. 5 , the micro-rough surface of embodiment 1 has a plurality of grooves extending along the vertical direction, and the extending directions of the grooves are substantially parallel. The width of the groove is about 0.1 to 4 microns, and the depth is less than or equal to 0.8 microns. At the peaks between the grooves, there are obvious microcrystalline clusters formed here. The height of the micro-crystal clusters is less than or equal to 2 microns, and each micro-crystal cluster is formed by stacking a plurality of micro-crystals with particle sizes ranging from 0.1 to 0.4 microns.

Referring to Figure 6 and Figure 7, the surface of the MLS-G copper foil is evenly covered by crystals with a particle size greater than 3 microns, and a small number of microcrystals aggregate with each other. It can be seen from the cross-sectional view that the microcrystals are distributed on the surface at intervals, and are not concentrated in a specific position.

Referring to Table 2, in terms of peel strength, the peel strength of Examples 1 to 3 is at least 4.75 lb/in, which is at least 18% greater than the industry standard of 4 lb/in. It can be seen that the micro-rough electrolytic copper foil of the present invention has a good bonding force with the substrate, which is beneficial to the subsequent process and maintains the product yield.

With regard to the performance of insertion loss, the insertion losses of Examples 1 to 3 at frequencies between 8 GHz and 20 GHz are better than those of Comparative Examples 1 to 4. It is worth mentioning that by controlling the surface morphology of the micro-rough surface and adjusting the Rlr value to be less than or equal to 1.3, the signal loss of the copper foil substrate at high frequencies can be significantly suppressed. In addition, the lower the Rlr value, the effect of further reducing the signal loss can be found.

From the above, it can be seen that the micro-roughened electrolytic copper foil of the present invention further optimizes the performance of insertion loss while maintaining good peel strength, and can effectively suppress signal loss.

The content disclosed above is only a preferred feasible embodiment of the present invention, and does not therefore limit the protection scope of the claims of the present invention. Therefore, all equivalent technical changes made by using the description of the present invention and the contents of the accompanying drawings are included in this document. within the protection scope of the claims of the invention.

Claims (6)

1. A copper foil substrate, characterized in that the copper foil substrate comprises: a substrate; and A micro-rough electrolytic copper foil, which includes a micro-rough surface attached to the substrate, the micro-rough surface is formed with a plurality of convex peaks, a plurality of grooves and a plurality of micro-crystal clusters, the groove has U-shaped cross-sectional profile and/or V-shaped cross-sectional profile, the average width of the groove is between 0.1 and 4 microns, the average depth of the groove is less than or equal to 1.5 microns, and the microcrystalline clusters are located on the top of the convex peak , each of the microcrystalline clusters is composed of a plurality of microcrystalline stacks with an average diameter of less than or equal to 0.5 microns, and the average height of each of the microcrystalline clusters is less than or equal to 2 microns; Wherein, the insertion loss of the copper foil substrate at 20GHz is between 0 and -1.5db/in; Wherein, the peel strength between the microrough electrolytic copper foil and the substrate is greater than 4.3 lb/in. 2 . The copper foil substrate according to claim 1 , wherein the insertion loss of the copper foil substrate at 16 GHz is between 0 and −1.2 db/in. 3. The copper foil substrate according to claim 2, wherein the insertion loss of the copper foil substrate at 8GHz is between 0 and -0.65db/in, and the insertion loss of the copper foil substrate at 12.89GHz is between 0 to -1.0db/in. 4. The copper foil substrate according to claim 3, wherein the insertion loss of the copper foil substrate at 8GHz is between 0 and -0.63db/in, and the insertion loss of the copper foil substrate at 12.89GHz is between 0 to -0.97db/in, the insertion loss of the copper foil substrate at 16GHz is between 0 and -1.15db/in, and the insertion loss of the copper foil substrate at 20GHz is between 0 and -1.45db/in. 5. The copper foil substrate according to claim 1, characterized in that, the average maximum width of the microcrystalline clusters is less than or equal to 5 microns; a plurality of the microcrystalline clusters form a bifurcated crystal group; each The average height of the microcrystal clusters is less than or equal to 1.8 microns; each of the microcrystal clusters is composed of a plurality of microcrystal stacks, and the average diameter of the microcrystals is less than or equal to 0.5 microns; the microrough electrolytic copper foil The Rlr value of the microrough surface is lower than 1.26. 6 . The copper foil substrate according to claim 1 , wherein the Dk value of the substrate at a frequency of 10 GHz is less than or equal to 4.0 and the Df value at a frequency of 10 GHz is less than or equal to 0.015.

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