CN111194134B

CN111194134B - Electrolytic copper foil subjected to fine roughening treatment and copper-clad substrate using same

Info

Publication number: CN111194134B
Application number: CN201811359646.3A
Authority: CN
Inventors: 宋云兴
Original assignee: Jinju Development Co ltd
Current assignee: Jinju Development Co ltd
Priority date: 2018-11-15
Filing date: 2018-11-15
Publication date: 2021-11-02
Anticipated expiration: 2038-11-15
Also published as: CN111194134A

Abstract

The invention discloses an electrolytic copper foil subjected to micro-roughening treatment and a copper-clad substrate using the electrolytic copper foil. The electrolytic copper foil is provided with a micro-rough surface, and the micro-rough surface is provided with a plurality of mountain-shaped structures and a plurality of concave structures corresponding to the mountain-shaped structures. Wherein a product (Sa x Spd) of an arithmetic average height (Sa) and a vertex density (Spd) of a plurality of the mountain-shaped structures is 150000 to 400000 micrometers per square millimeter as determined in accordance with International Standard ISO25178, and an arithmetic average waviness (Wa) of a plurality of the mountain-shaped structures is greater than 0.06 micrometers and 1.5 micrometers or less as determined in accordance with Japanese Industrial Standard JIS B0601-2001. Therefore, the electrolytic copper foil can give consideration to both bonding strength and electrical performance.

Description

Electrolytic copper foil subjected to fine roughening treatment and copper-clad substrate using same

Technical Field

The present invention relates to an electrolytic copper foil and use thereof, and more particularly to an electrolytic copper foil subjected to fine roughening treatment and a copper-clad substrate using the same.

Background

With the development of the information and electronics industries, high frequency and high speed signal transmission has become a part of modern circuit design and manufacture. In order to meet the requirements of high-frequency and high-speed signal transmission, the copper foil substrate used in the electronic product needs to have good insertion loss (insertion loss) performance at high frequency so as to prevent excessive loss of high-frequency signals during transmission. The insertion loss of the copper foil substrate is highly correlated with the surface roughness thereof. When the surface roughness is reduced, the insertion loss performs better, otherwise it is not. However, the reduction of the roughness also causes a drop in the peel strength between the copper foil and the substrate, which affects the yield of the rear-end product. Therefore, it is an object of the present invention to maintain peel strength at an industrial level and provide good insertion loss performance.

Disclosure of Invention

The present invention is directed to an electrolytic copper foil subjected to a fine roughening treatment, which overcomes the disadvantages of the prior art. Also disclosed is a copper-clad substrate using such an electrodeposited copper foil subjected to fine roughening treatment.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention is: a micro-roughened electrolytic copper foil has a micro-roughened surface having a plurality of mountain-shaped structures and a plurality of recessed structures corresponding to the mountain-shaped structures. Wherein a product (Sa x Spd) of an arithmetic average height (Sa) and a vertex density (Spd) of the plurality of mountain-shaped structures is 150000 to 400000 micrometers per square millimeter as measured according to International Standard ISO25178, and an arithmetic average waviness (Wa) of the plurality of mountain-shaped structures is greater than 0.06 micrometers and 1.5 micrometers or less as measured according to Japanese Industrial Standard JIS B0601-2001.

In order to solve the above technical problem, another technical solution adopted by the present invention is: a copper-clad substrate comprises a substrate and an electrolytic copper foil subjected to fine roughening treatment. The electrolytic copper foil subjected to the micro-roughening treatment is attached to one surface of the substrate and is provided with a micro-rough surface which is connected with the surface, wherein the micro-rough surface is provided with a plurality of mountain-shaped structures and a plurality of concave structures corresponding to the mountain-shaped structures. Wherein a product (Sa x Spd) of an arithmetic average height (Sa) and a vertex density (Spd) of the plurality of mountain-shaped structures is 150000 to 400000 micrometers per square millimeter as measured according to International Standard ISO25178, and an arithmetic average waviness (Wa) of the plurality of mountain-shaped structures is greater than 0.06 micrometers and 1.5 micrometers or less as measured according to Japanese Industrial Standard JIS B0601-2001.

In an embodiment of the invention, Sa × Spd of the mountain structures is 240000 to 350000 μm/mm.

In an embodiment of the invention, an arithmetic mean waviness (Wa) of the plurality of mountain structures is greater than 0.1 micron and less than 1.5 microns.

In an embodiment of the present invention, each of the recessed structures has a U-shaped cross-sectional profile and/or a V-shaped cross-sectional profile.

In one embodiment of the present invention, the micro-rough surface has a surface roughness (Rz) of 2.3 μm or less as measured in accordance with JIS 94.

One of the advantages of the present invention is that the electrolytic copper foil with micro-roughening treatment provided by the present invention can effectively reduce the signal transmission loss without reducing the bonding force between the copper foil and the substrate, that is, can achieve both the bonding force of the copper foil and the signal transmission loss, by controlling the product (Sa × Spd) of the arithmetic mean height (Sa) and the peak density (Spd) of the micro-roughened surface and the arithmetic mean waviness (Wa) within a specific range.

For a better understanding of the features and technical content of the present invention, reference should be made to the following detailed description and accompanying drawings, which are provided for purposes of illustration and description only and are not intended to limit the invention.

Drawings

FIG. 1 is a schematic view showing the structure of an electrolytic copper foil subjected to a fine roughening treatment of the present invention.

Fig. 2 is an enlarged schematic view of section II of fig. 1.

Fig. 3 is a schematic structural diagram of the copper-clad substrate of the present invention.

Fig. 4 is another structural schematic diagram of the copper-clad substrate of the present invention.

FIG. 5 is a schematic view of an electrolytic apparatus used for producing the electrolytic copper foil subjected to fine roughening treatment of the present invention.

FIG. 6 is a scanning electron microscope photograph showing the surface morphology of the micro-roughened electrolytic copper foil of example 1.

FIG. 7 is a scanning electron microscope photograph showing the cross-sectional form of the micro-roughened electrolytic copper foil of example 1.

FIG. 8 is a scanning electron microscope photograph showing the surface morphology of the electrolytic copper foil of comparative example 3.

FIG. 9 is a scanning electron microscope photograph showing the cross-sectional form of the electrolytic copper foil of comparative example 3.

Detailed Description

Since electronic products are continuously developing toward miniaturization, high speed, multi-functionalization and high reliability, the invention provides an electrolytic copper foil subjected to micro roughening treatment, which is helpful for forming a fine circuit with a micro line width and a micro line pitch and can ensure the bonding strength to a base material; more importantly, the formed circuit can effectively reduce the transmission loss of signals.

The following description will be made of embodiments of the present disclosure relating to "electrolytic copper foil subjected to fine roughening treatment and copper-clad substrate using the same" with reference to specific examples, and those skilled in the art will understand the advantages and effects of the present disclosure from the contents disclosed in the present specification. The invention is capable of other and different embodiments and its several details are capable of modification and various other changes, which can be made in various details within the specification and without departing from the spirit and scope of the invention. The drawings of the present invention are for illustrative purposes only and are not intended to be drawn to scale. The following embodiments will further explain the related art of the present invention in detail, but the disclosure is not intended to limit the scope of the present invention.

It will be understood that, although the terms "first," "second," "third," etc. may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are used primarily to distinguish one element from another element or from one signal to another signal. In addition, the term "or" as used herein should be taken to include any one or combination of more of the associated listed items as the case may be.

Herein, the arithmetic mean height (Sa) is determined according to international standard ISO25178, which represents the mean of the absolute values of the differences in height at points on a mean plane relative to a surface; this corresponds to a parameter obtained by enlarging Ra (arithmetic mean height of line) in a plane. The vertex density (Spd) is also determined according to international standard ISO25178, which represents the number of vertices of a hill-like structure per unit area; a larger value of Spd indicates a larger number of contact points with other objects. The Sa and Spd values can be calculated by measuring a surface profile (profile) of a predetermined area of the roughened surface with a laser microscope. The arithmetic mean waviness (Wa) is measured in accordance with japanese industrial standard JIS B0601-2001, and represents the gradient of a surface profile curve.

Referring to fig. 1, the electrodeposited copper foil 1 with a micro-roughening treatment according to the present invention has at least one micro-roughened surface 10, wherein the micro-roughened surface 10 has a plurality of mountain structures 11 and a plurality of valley structures 12 corresponding to the mountain structures 11. It is noted that, for the microrough surface 10, the product (Sa × Spd) of the arithmetic mean height (Sa) and the vertex density (Spd) of the mountain structures 11, as determined according to international standard ISO25178, may be 150000 to 400000 micrometers per square millimeter, preferably 240000 to 350000 micrometers per square millimeter; further, the arithmetic mean waviness (Wa) of the mountain structure 11 measured in accordance with Japanese Industrial Standard JIS B0601-2001 may be more than 0.06 μm and 1.5. mu.m, preferably more than 0.1 μm and 1.5. mu.m. Thereby, the electrolytic copper foil 1 subjected to the fine roughening treatment of the present invention can have good electrical properties such as optimized Insertion loss (Insertion loss) performance. Further, the surface roughness (Rz) of the microrough surface 10, which is measured in accordance with japanese industrial standard JIS94, is 2.3 μm or less, which contributes to the micro-shrinkage of the line width and the line pitch.

As shown in fig. 2, in the micro-rough surface 10, a micro-crystal cluster 13 is formed on each of the mountain structures 11, and the micro-crystal cluster 13 may include at least one whisker W stacked by a plurality of micro-crystals C. The arrangement of the microcrystalline clusters 13 is not particularly limited, and they may be arranged regularly, that is, in substantially the same direction, but not limited thereto. The average height of the microcrystallized clusters 13 may be less than 2 microns, preferably less than 1.8 microns, and more preferably less than 1.6 microns. Herein, the average height of the micro crystal clusters 13 refers to a perpendicular distance from the top surfaces of the micro crystal clusters 13 to the top surfaces of the mountain structures 11.

In the present embodiment, as shown in fig. 2, the microcrystalline cluster 13 may be branched to include a plurality of whiskers W extending in different directions. Each whisker W may have stacked therein, in the height direction thereof, 15 or less microcrystals C, preferably 13 or less, more preferably 10 or less, and still more preferably 8 or less. The average outer diameter of the microcrystalline C may be less than 0.5 micron, preferably from 0.05 to 0.5 micron, more preferably from 0.1 to 0.4 micron.

In addition, as shown in fig. 2, when the Wa value of the mountain-shaped structures 11 on the micro-rough surface 10 falls within the above range, each of the concave structures 12 has a U-shaped cross-sectional profile and/or a V-shaped cross-sectional profile; therefore, more glue can be filled in each concave structure 12 to increase the bonding force between the copper foil and the base material, improve the Peel strength (Peel strength) of the copper foil and the base material, and simultaneously take the electrical property (Insertion loss) into consideration. The average depth of the recessed features 12 may be less than 1.5 microns, preferably less than 1.3 microns, and more preferably less than 1 micron. The average width of the recessed features 12 may be between 0.5 and 4 microns, preferably between 0.6 and 3.8 microns.

In the present embodiment, the electrolytic copper foil 1 subjected to the fine roughening treatment can be produced by subjecting one surface (e.g., a bright surface) of a base foil to electrolytic roughening treatment; for example, a reversed copper foil (RTF), a high temperature expanded copper foil (HTE), or a very low roughness copper foil (VLP) may be used as the base foil, and the electrolytic roughening treatment may be performed on the surface of the base foil by an existing electrolytic apparatus, such as a continuous or batch type electrolytic apparatus. Preferably, the electrolysis device is a continuous electrolysis device which can comprise a plurality of electrolysis baths and a plurality of electrolysis rollers which are matched with each other; the electrolytic bath can contain copper-containing electrolyte with different compositions, and can apply constant current. The production speed of the electrolysis device can be controlled between 5 and 20m/min, and the production temperature is controlled between 20 and 60 ℃.

Further, the electrolytic roughening treatment may employ a copper-containing electrolyte having a composition that includes a copper ion source, a metal additive, and a non-metal additive. Examples of the copper ion source include copper sulfate and copper nitrate. Examples of the metal additive include cobalt, iron, zinc, and oxides and salts thereof. Examples of the nonmetallic additives include gelatin, organonitrides, Hydroxyethylcellulose (HEC), polyethylene glycol (PEG), Sodium 3-mercapto-1-propanesulfonate (Sodium 3-captopropansulfonate, MPS), Sodium polydithiodipropanesulfonate (Bis- (Sodium sulfopropyl) -disulphide, SPS), and thiourea-based compounds.

In one example, the electrolytic graining treatment may have only two stages, and the composition of the copper-containing electrolytic solution used in the two stages may be the same or different. For example, the surface of the base foil may be treated with two different copper-containing electrolytes in succession; the concentration of copper ions in the first copper-containing electrolyte may be 10 to 30g/l, the concentration of the acid may be 70 to 100g/l, and the concentration of the metal additive may be 150 to 300 g/l; the concentration of copper ions in the second copper-containing electrolyte may be 70 to 100g/l, the concentration of the acid may be 30 to 60g/l, and the concentration of the metal additive may be 15 to 100 g/l.

A constant voltage and a constant current may be applied during the electrolytic graining treatment. In the above examples, the electrolytic graining treatment isThe first stage may apply 25 to 40A/m²The second stage of the electrolytic graining treatment may be applied at a constant current of 20 to 30A/m²The constant current of (2); alternatively, the first stage of electrolytic roughening treatment may be applied at 30 to 56A/m²At a constant current, the second stage of the electrolytic graining treatment may be applied at 23 to 26A/m²The constant current of (2). Incidentally, the electrolytic current may be output in a pulse waveform or a saw-type waveform during the treatment. Further, when a constant voltage is applied, a constant current applied at each stage of the electrolytic graining treatment must fall within the above range.

In another example, the electrolytic graining treatment may have more than two stages, the above two copper-containing electrolytic solutions may be alternately used during the treatment, and the electrolytic current may be controlled to be 1 to 60A/m². For example, the electrolytic roughening treatment may be carried out in four stages, the first and second stages being operated under the same conditions as in the above example, and the third stage being carried out using a first copper-containing electrolyte solution and being applied at a rate of 1 to 8A/m²The fourth stage may employ a second copper-containing electrolyte and may be applied at a rate of 40 to 60A/m²The constant current of (2). The electrolytic graining treatment may be carried out in five stages or more, and after the fifth stage, the electrolytic current may be controlled to be less than 5A/m². Similarly, the electrolysis current may be output in a pulsed or saw-type waveform during the treatment. Further, when a constant voltage is applied, a constant current applied at each stage of the electrolytic graining treatment must fall within the above range.

It should be noted that the arrangement and extending direction of the micro-crystalline clusters 13 and the recessed structures 12 on the micro-rough surface 10 can be controlled by the flow field of the copper-containing electrolyte. Specifically, when no flow field is applied or turbulence is formed, the formed micro crystal clusters 13 are in disordered arrangement; when a flow field is applied to cause the copper-containing electrolyte to flow in a particular direction over the surface of the base foil, at least a portion of the resulting microcrystalline clusters 13 will assume an ordered arrangement, i.e., the microcrystalline clusters 13 are arranged in substantially the same direction. However, the above-mentioned example is only one of the possible examples and is not intended to limit the present invention; in other examples, the microstructure on the microrough surface 10 may also be formed by physical means, such as scratching the surface of the base foil with a steel brush.

Referring to fig. 3 and 4, the present invention also provides a copper-clad substrate L, which includes a substrate 2 and at least one electrodeposited copper foil 1 subjected to fine roughening treatment. In practice, as shown in fig. 3, the electrodeposited copper foil 1 subjected to the fine roughening treatment may be only one piece and attached to one surface of the substrate 2; as shown in fig. 4, the electrolytic copper foil 1 subjected to the fine roughening treatment may have two pieces, and be attached to the opposite surfaces of the substrate 2, respectively; wherein the micro-roughened surface 10 of the electrolytic copper foil 1 subjected to the micro-roughening treatment is bonded to the surface of the substrate 2.

The substrate 2 may be made of medium-loss (Mid-loss) and Low-loss (Low-loss) materials, wherein the difference in electrical properties of the copper foil is more pronounced with Low-loss materials. The term "medium loss material" refers to a dielectric material having a Dk value (dielectric constant) of 3.5 to 4.0 and a Df value (dielectric loss) of greater than 0.010 and equal to or less than 0.015; the term "low loss material" refers to a dielectric material having a Dk value of 3.2 to 3.8 and a Df value of greater than 0.005 and equal to or less than 0.010.

The substrate 2 can be a composite material formed by impregnating a prepreg with a synthetic resin and curing the impregnated prepreg. Examples of the prepreg sheet include: phenolic cotton paper, resin fiber cloth, resin fiber nonwoven fabric, glass plate, glass woven fabric, or glass nonwoven fabric. Examples of the synthetic resin include: epoxy resin, polyester resin, polyimide resin, cyanate ester resin, bismaleimide triazine resin, polyphenylene ether resin, or phenol resin. The synthetic resin layer may be a single layer or a plurality of layers, and is not limited. Substrate 2 may be selected from, but not limited to, EM891, IT958G, IT150DA, S7040G, S7439G, MEGTRON 4, MEGTRON 6, or MEGTRON 7.

Examples 1 to 3 will be exemplified below, and compared with comparative examples 1 to 4, to illustrate the advantages of the present invention.

[ example 1]

Referring to FIG. 4 in conjunction with FIG. 5, the micro-roughened surface 10 of the electrodeposited copper foil 1 subjected to the micro-roughening treatment is formed by using a continuous type electrolytic apparatus 3. The continuous electrolyzer 3 comprises a feed roller 31, a receiving roller 32, a plurality of electrolytic cells 33 arranged between the feed roller 31 and the receiving roller 32, a plurality of electrolytic roller sets 34 respectively arranged above the electrolytic cells 33, and a plurality of auxiliary roller sets 35 respectively arranged in the electrolytic cells 33. Wherein, a set of electrodes 331 (such as platinum electrodes) is disposed in each electrolytic cell 33, each electrolytic roller set 34 comprises two electrolytic rollers 341, each auxiliary roller set 35 comprises two auxiliary rollers 351, and the electrodes 231 in each electrolytic cell 33 and the corresponding electrolytic roller set 34 are electrically connected to an external power supply.

Example 1 an inverse copper foil (RTF) was used as a base foil, which is a product of jinju development ltd (model RG 311). The base foil is firstly wound on the feeding roller 31, then sequentially wound on the electrolytic roller group 34 and the auxiliary roller group 35, and then wound on the receiving roller 32. The composition and operating conditions of the copper-containing electrolyte used in each cell 33 are shown in Table 1; the base foil was subjected to electrolytic roughening treatment in a plurality of electrolytic cells 33 in order at a production speed of 10m/min to form a finely roughened electrolytic copper foil 1 having a surface roughness Rz (JIS94) of 2.3 μm or less, and the surface and cross-sectional structures thereof are shown in FIGS. 6 and 7, respectively.

The arithmetic mean height (Sa) and the peak density (Spd) of the micro-rough surface 10 of the electrodeposited copper foil 1 subjected to the fine roughening treatment are obtained by directly measuring the roughness profile of the micro-rough surface 10 by a laser microscope. Preferably, the electrodeposited copper foil 1 subjected to the fine roughening treatment is attached to a PP substrate, so that the concave-convex profile of the micro-roughened surface 10 is transferred to the PP substrate, and after the copper foil is removed by selective etching, the concave-convex profile of the PP substrate surface is measured to obtain the Sa value and the Spd value.

The insertion loss of the electrodeposited copper foil 1 subjected to the fine roughening treatment was measured by a strip line method, and the results are shown in table 2. Example 1 measurements were performed at a plurality of frequencies, such as 4GHz, 8GHz, 12.89GHz, and 16 GHz.

The peel strength of the copper-clad substrate L was measured by bonding two pieces of electrodeposited copper foil 1 subjected to fine roughening treatment to one substrate 2 (low-loss prepreg, model No. S7439G), wherein the micro-roughened surface 10 was coated with a copper silane coupling agent, and curing the copper silane coupling agent, and then measuring the cured copper silane coupling agent according to the IPC-TM-6504.6.8 test method, and the results are shown in table 2.

[ examples 2 and 3]

The composition of the base foil, the electrolytic apparatus and the copper-containing electrolytic solution was the same as in example 1, the operating conditions were as shown in Table 1, and the base foil was subjected to electrolytic graining treatment at a production speed of 10 m/min. A piece of electrodeposited copper foil 1 with fine roughening treatment was taken and measured for Sa value and Spd value in the same manner as in example 1, and the results are shown in Table 2. Two pieces of electrodeposited copper foil 1 subjected to fine roughening treatment were bonded to one substrate 2 (low-loss prepreg, model No. S7439G) to form a copper-clad substrate L, and the peel strength was measured in the same manner as in example 1, and the results are shown in table 2.

Comparative examples 1 and 2

The composition of the base foil, the electrolytic apparatus and the copper-containing electrolytic solution was the same as in example 1, the operating conditions were as shown in Table 1, and the base foil was subjected to electrolytic graining treatment at a production speed of 10 m/min. A piece of electrodeposited copper foil 1 with fine roughening treatment was taken and measured for Sa value and Spd value in the same manner as in example 1, and the results are shown in Table 2. Two pieces of electrolytic copper foil 1 subjected to micro roughening treatment are attached to a substrate 2(a low-loss prepreg material, the model is S7439G, the model is S7439G) to form a copper-clad substrate L; and then, the other two pieces of electrolytic copper foil 1 subjected to the micro roughening treatment are attached to another substrate (a middle loss prepreg material, the model is S7439G, the model is S7040G) to form another copper-clad substrate L. Then, the peel strength of these copper-clad substrates L was measured in the same manner as in example 1, and the results are shown in table 2.

Comparative example 3

The type of the reverse copper foil adopted by the base foil is as follows: RTF3 (hereinafter RTF3 copper foil) is shown in FIG. 8 and FIG. 9 for its surface and cross-sectional structure, respectively. A piece of RTF3 copper foil was used to measure the Sa value and Spd value in the same manner as in example 1, and the results are shown in Table 2. Two pieces of electrolytic copper foil 1 subjected to micro roughening treatment are attached to a substrate 2(a low-loss prepreg material, the model is S7439G) to form a copper-clad substrate L; and then, another two pieces of electrolytic copper foil 1 subjected to micro roughening treatment are attached to another substrate 2(a middle loss prepreg, model number is S7040G) to form another copper-clad substrate L. Then, the peel strength of these copper-clad substrates L was measured in the same manner as in example 1, and the results are shown in table 2.

TABLE 1

	First groove	Second groove	Third groove	The fourth groove	The fifth groove	The sixth groove
							Cu²⁺(g/l)	15.5～20.5	86.5～90.5	15.5～20.5	86.5～90.5	15.5～20.5	86.5～90.5
Cl(ppm)	<3	<3	<3	<3	<3	<3
							H₂SO₄(g/l)	83～87	45～55	83～87	45～55	83～87	45～55
Metal additive (ppm)	180～220	30～40	180～220	30～40	180～220	30～40
							Example 1 (A/m)²)	30.56	24.60	48.15	4.63	1.05	4.92
Example 2 (A/m)²)	33.34	24.60	48.15	4.63	1.05	4.92
							Example 3 (A/m)²)	36.11	24.60	48.15	4.63	1.05	4.92
Comparative example 1 (A/m)²)	46.30	24.60	48.15	4.63	1.05	4.92
							Comparative example 2 (A/m)²)	55.56	24.60	48.15	4.63	1.05	4.92

TABLE 2

Table 3 shows RTF3 as the electrical comparison standard

Referring to fig. 6 and 7 in conjunction with fig. 2, the micro-rough surface 10 of example 1 has a plurality of recessed structures 12 (e.g., grooves) extending in substantially the same direction; the width of the recessed features 12 is between about 0.1 microns and 4 microns and the depth is less than or equal to 0.8 microns. Obvious micro-crystal clusters 13 are arranged on the mountain-shaped structures 11 adjacent to the concave structures 12; the height of the micro-crystal clusters 13 is less than or equal to 2 microns, and each micro-crystal cluster 13 includes whiskers W stacked from a plurality of micro-crystals C having an average outer diameter of less than about 0.5 microns.

Referring again to fig. 8 and 9, the RTF3 copper foil has a plurality of micro-crystals with a particle size of about 1 μm on the surface, and the micro-crystals are uniformly distributed on the surface, i.e. not concentrated at specific locations, but only partially aggregated.

Referring to tables 2 and 3, when the low-loss prepreg (model number S7439G) is used as the substrate 2 in the copper-clad substrates L of examples 1 to 3, the peel strength is at least 4.10lb/in, which is higher than the industry standard 4 lb/in. When the copper-clad substrate L of examples 1 to 3 uses a lossy prepreg (model number S7040G) as the substrate 2, the peel strength is at least 4.10lb/in, which is also higher than the industry standard of 4 lb/in. Therefore, the copper-clad substrate L of the invention has the peeling strength higher than the standard in the industry and has good electrical performance; this is beneficial to the subsequent PCB manufacturing process and can maintain the stable electrical quality of the terminal product.

As shown in Table 3, the insertion loss between the frequencies of 4GHz and 16GHz was superior to that of comparative example 3 in examples 1 to 3 and comparative examples 1 and 2, regardless of whether low-loss prepreg or medium-loss prepreg was used. It is to be noted that the transmission loss of the high frequency signal can be effectively reduced by controlling the uneven surface morphology of the micro-rough surface 10 so that both the Sa × Spd value and the Wa value fall within a specific range.

Furthermore, when the Sa x Spd value of the micro-rough surface 10 is less than 39000 μm/mm²And Wa is greater than 0.08, the copper-clad substrate L (using a low-loss prepreg, type S7439G) has excellent insertion loss performance. Furthermore, the insertion loss of the copper-clad substrate L at 4GHz is between-0.350 dB/in and-0.371 dB/in; if considering peelingThe insertion loss at 4GHz is preferably between-0.352 dB/in and-0.369 dB/in. The insertion loss of the copper-clad substrate L at 8GHz is between-0.601 dB/in and-0.635 dB/in, and if considering the peeling strength, the insertion loss at 8GHz is preferably between-0.619 dB/in and-0.628 dB/in. The insertion loss of the copper-clad substrate L at 12.89GHz is between-0.885 dB/in and-0.956 dB/in, and if considering the peeling strength, the insertion loss at 12.89GHz is preferably between-0.919 dB/in and-0.922 dB/in. The insertion loss of the copper-clad substrate L at 16GHz is between-1.065 dB/in and-1.105 dB/in, and if considering the peeling strength, the insertion loss at 16GHz is preferably between-1.083 dB/in and-1.099 dB/in. From this fact, it is understood that the electrolytic copper foil 1 subjected to the fine roughening treatment of the present invention is effective in reducing the loss at the time of signal transmission even at a frequency of 4GHz to 16 GHz.

As is clear from the above, the electrodeposited copper foil 1 with fine roughening treatment of the present invention can effectively suppress signal loss by further optimizing the insertion loss performance while maintaining good peel strength.

The disclosure is only a preferred embodiment of the invention and should not be taken as limiting the scope of the invention, so that the invention is not limited by the disclosure of the specification and drawings.

Claims

1. A micro-roughened electrolytic copper foil having a micro-roughened surface, and the micro-roughened surface having a plurality of mountain-like structures and a plurality of recessed structures corresponding to the mountain-like structures, characterized in that the product of the arithmetic mean height of the plurality of mountain-like structures and the peak density is 150000 to 400000 μm/mm as measured according to International Standard ISO25178, the arithmetic mean waviness of the plurality of mountain-like structures is greater than 0.06 μm and 1.5 μm or less as measured according to Japanese Industrial Standard JIS B0601-2001, and the surface roughness of the micro-roughened surface is 2.3 μm or less as measured according to Japanese Industrial Standard JIS B94, and the mean width of at least one of the plurality of recessed structures corresponding to the mountain-like structures is 0.5 to 4 μm.

2. The fine-grained treated electrolytic copper foil according to claim 1, wherein the product of the arithmetic mean height and the peak density of a plurality of said mountain-shaped structures is 240000 to 350000 μm/mm.

3. The fine-grained treated electrolytic copper foil according to claim 1, wherein an arithmetic mean undulation of a plurality of said mountain structures is more than 0.1 μm and less than 1.5. mu.m.

4. The micro-roughened electrolytic copper foil according to claim 1, wherein each of the depression structures has a U-shaped cross-sectional profile and/or a V-shaped cross-sectional profile.

5. A copper-clad substrate, comprising:

a substrate; and

a micro-roughened electrolytic copper foil attached on a surface of the substrate and having a micro-roughened surface bonded to the surface, wherein the micro-roughened surface has a plurality of mountain-shaped structures and a plurality of recessed structures corresponding to the mountain-shaped structures;

wherein a product of an arithmetic mean height and a vertex density of a plurality of the mountain structures measured according to international standard ISO25178 is 150000 to 400000 micrometers per square millimeter, an arithmetic mean undulation of a plurality of the mountain structures measured according to japanese industrial standard JIS B0601-2001 is more than 0.06 micrometers and 1.5 micrometers or less, and a surface roughness of the micro-rough surface measured according to japanese industrial standard JIS94 is 2.3 micrometers or less, and an average width of at least one of the plurality of the concave structures with respect to the mountain structure is 0.5 to 4 micrometers.

6. The copper-clad substrate of claim 5, wherein the product of the arithmetic mean height of the plurality of mountain structures and the vertex density is 240000 to 350000 μm/mm.

7. The copper-clad substrate according to claim 5, wherein an arithmetic mean undulation of the plurality of mountain structures is more than 0.1 μm and less than 1.5. mu.m.

8. The copper-clad substrate according to claim 5, wherein each of the recessed structures has a U-shaped cross-sectional profile and/or a V-shaped cross-sectional profile.

9. The copper-clad substrate of claim 5, wherein the substrate is formed of a prepreg material having a dielectric constant of 3.2 to 3.8, a dielectric loss of greater than 0.005 and equal to or less than 0.010, and the copper-clad substrate has an insertion loss of-0.35 dB/in to-0.41 dB/in at 4GHz, wherein the substrate is formed of a prepreg material having a dielectric constant of 3.5 to 4.0, a dielectric loss of greater than 0.010 and equal to or less than 0.015, and the copper-clad substrate has an insertion loss of-0.45 dB/in to-0.49 dB/in at 4 GHz.

10. The copper-clad substrate of claim 5, wherein the substrate is formed of a prepreg material having a dielectric constant of 3.2 to 3.8, a dielectric loss of greater than 0.005 and equal to or less than 0.010, and the copper-clad substrate has an insertion loss of-0.61 dB/in to-0.69 dB/in at 8GHz, wherein the substrate is formed of a prepreg material having a dielectric constant of 3.5 to 4.0, a dielectric loss of greater than 0.010 and equal to or less than 0.015, and the copper-clad substrate has an insertion loss of-0.76 dB/in to-0.86 dB/in at 8 GHz.

11. The copper-clad substrate of claim 5, wherein the substrate is formed from a prepreg material having a dielectric constant of 3.2 to 3.8 and a dielectric loss of greater than 0.005 and equal to or less than 0.010, and the copper-clad substrate has an insertion loss of-0.90 dB/in to-1.01 dB/in at 12.89GHz, wherein the substrate is formed from a prepreg material having a dielectric constant of 3.5 to 4.0 and a dielectric loss of greater than 0.010 and equal to or less than 0.015, and the copper-clad substrate has an insertion loss of-1.06 dB/in to-1.30 dB/in at 12.89 GHz.

12. The copper-clad substrate of claim 5, wherein the substrate is formed of a prepreg material having a dielectric constant of 3.2 to 3.8, a dielectric loss of greater than 0.005 and equal to or less than 0.010, and the copper-clad substrate has an insertion loss of-1.03 dB/in to-1.20 dB/in at 16GHz, wherein the substrate is formed of a prepreg material having a dielectric constant of 3.5 to 4.0, a dielectric loss of greater than 0.010 and equal to or less than 0.015, and the copper-clad substrate has an insertion loss of-1.4 dB/in to-1.54 dB/in at 16 GHz.

13. The copper-clad substrate according to claim 5, wherein the substrate is formed of a prepreg material having a dielectric constant of 3.2 to 3.8 and a dielectric loss value of more than 0.005 and not more than 0.010, the substrate has a Dk value of more than or equal to 3.2 and not more than 3.8 and a Df value of more than 0.005 and not more than 0.010 at 10GHz, wherein the substrate is formed of a prepreg material having a dielectric constant of 3.5 to 4.0 and a dielectric loss value of more than 0.010 and not more than 0.015, the substrate has a Dk value of more than or equal to 3.5 and not more than 4.0 and a Df value of more than 0.010 and not more than 0.015 at 10 GHz.