TW202102722A - Advanced treated electrodeposited copper foil having long and island-shaped structures and copper clad laminate using the same - Google Patents

Abstract

An advanced reverse-treated electrodeposited copper foil having long and island-shaped microstructures and a copper clad laminate using the same are provided. The advanced reverse-treated electrodeposited copper foil includes a micro-roughened surface. The micro-roughened surface has a plurality of copper crystals, a plurality of copper crystal whiskers and a plurality of copper crystal groups which form into a long and island-shaped pattern. Therefore, the advanced reverse-treated electrodeposited copper foil has good bonding strength relative to a resin-based composite material, and can increase signal integrity and reduce signal transmission loss so as to meet the requirements of 5G applications.

Description

Advanced reverse electrolytic copper foil with long island-like microstructure and copper foil substrate using the same

The invention relates to an electrolytic copper foil, in particular to an advanced reverse electrolytic copper foil with a long island-shaped microstructure, and a copper foil substrate using the same.

With the development of the information and electronic industries, high-frequency and high-speed signal transmission has become a part of modern circuit design and manufacturing. In order to meet the needs of electronic products for high-frequency and high-speed signal transmission, copper clad laminates (CCL) need to prevent excessive insertion loss during transmission of high-frequency signals in order to have good signal integrity (signal integrity). integrity, SI). Among them, the insertion loss performance of the copper foil in the copper foil substrate is highly correlated with the roughness of the surface treatment surface. The reason is that the skin effect will occur during high-frequency and high-speed signal transmission: the current distribution inside the conductor is uneven A phenomenon. As the distance from the surface of the conductor gradually increases, the current density in the conductor decreases exponentially, that is, the current in the conductor is concentrated on the surface of the conductor. Therefore, the smaller the surface area of the conductor surface treatment surface, the more conducive to high-frequency and high-speed signal transmission; however, , The larger the surface area, the better the peel strength, which is in conflict with the signal integrity. Furthermore, the flatter the surface of the copper foil, the better the signal integrity, and the larger the surface area of the copper foil. The peel strength is better. Therefore, the technical field urgently needs to develop a copper foil substrate that can simultaneously take into account signal integrity and peel strength.

The technical problem to be solved by the present invention is to provide an advanced reverse electrolytic copper foil with a long island-like microstructure in view of the deficiencies of the prior art, which can be applied to the high-frequency and high-speed 5G field, and can maintain the characteristics required by the target application , For example, to maintain the peel strength of the electrolytic copper foil (peel strength). The invention also provides a copper foil substrate using the advanced reverse electrolytic copper foil, which can be used as a high-frequency and high-speed substrate.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide an advanced reverse electrolytic copper foil with a long island-like microstructure, which includes a micro-roughened surface. The micro-roughened surface has a plurality of copper crystals distributed non-uniformly, wherein different numbers of the copper crystals are stacked together to form respective copper whiskers, and different numbers of the copper whiskers are agglomerated together To form their respective copper crystal clusters. Under the observation of a scanning electron microscope with an inclination angle of 35 degrees and a magnification of 10,000 times, the micro-roughened surface has the following structural characteristics: (1) At least ten first smooth surfaces with a length of 250 nm and a width of 250 nm (2) at least one second smooth region with a length of 500 nm and a width of 500 nm; (3) at least one long island-like microstructure with a length of 1,500 nm or more, and there are at least three of the long island-like microstructures The copper crystals and/or copper whiskers; and (4) at least two linear copper-free regions with a length of 1,000 nm or more.

In order to solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide a copper foil substrate, which includes a substrate and an advanced reverse electrolytic copper foil, and the advanced reverse electrolytic copper foil is disposed on the On the substrate, there is a micro-roughening treatment surface bonded to a surface of the substrate. The micro-roughened surface has a plurality of copper crystals distributed non-uniformly, wherein different numbers of the copper crystals are stacked together to form respective copper whiskers, and different numbers of the copper whiskers are agglomerated together To form their respective copper crystal clusters. Under the observation of a scanning electron microscope with an inclination angle of 35 degrees and a magnification of 10,000 times, the micro-roughened surface has the following structural characteristics: (1) At least ten first smooth surfaces with a length of 250 nm and a width of 250 nm (2) at least one second smooth region with a length of 500 nm and a width of 500 nm; (3) at least one long island-like microstructure with a length of 1,500 nm or more, and there are at least three of the long island-like microstructures The copper crystals and/or copper whiskers; and (4) at least two linear copper-free regions with a length of 1,000 nm or more.

In an embodiment of the present invention, the copper crystals do not exist in the first smooth area and the second smooth area.

In an embodiment of the present invention, each of the copper whiskers has a top copper crystal.

In an embodiment of the present invention, a plurality of the top copper crystals are cone-shaped, rod-shaped, and/or spherical.

In an embodiment of the present invention, the surface roughness (Rz jis94) of the micro-roughened surface is less than 2.1 microns.

In an embodiment of the present invention, the micro-roughened surface further includes a plurality of convex peaks and a plurality of grooves located between the plurality of convex peaks, and a plurality of the copper crystals and a plurality of the copper Whiskers are formed on the plurality of convex peaks corresponding to the plurality of copper crystal clusters.

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

One of the beneficial effects of the present invention is that the advanced inverted copper foil of the present invention can have at least ten copper crystals with a length of 250 nm and A first smooth region with a width of 250 nm, at least one second smooth region with a length of 500 nm and a width of 500 nm, and at least one long island-like microstructure with a length of 1,500 nm or more, and at least one of the long island-like microstructures The three technical means of “copper crystals and/or copper whiskers” can reduce insertion loss and improve signal integrity without compromising the peel strength, so as to adapt to the high frequency and high speed of signal transmission. Meet the needs of 5G applications.

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

The following are specific examples to illustrate the implementation of the "advanced reverse electrolytic copper foil and copper foil substrate using the same" disclosed in the present invention. Those skilled in the art can understand the present invention from the content disclosed in this specification. Advantages and effects. The present invention can be implemented or applied through other different specific embodiments, and various details in this specification can also be based on different viewpoints and applications, and various modifications and changes can be made without departing from the concept of the present invention. In addition, the drawings of the present invention are merely schematic illustrations, and are not drawn according to actual size, and are stated in advance. The following embodiments will further describe the related technical content of the present invention in detail, but the disclosed content is not intended to limit the protection scope of the present invention. In addition, the term "or" used in this document may include any one or a combination of more of the associated listed items depending on the actual situation.

Referring to FIGS. 1 to 3, the present invention provides a copper foil substrate C, which includes a substrate 1 and at least one advanced reverse electrolytic copper foil 2 disposed on the substrate 1. In this embodiment, the number of advanced reverse electrolytic copper foils 2 is two, each of which has an uneven micro-roughened surface 20 to be bonded to the surface of the substrate 1, but the present invention is not limited to this. In other embodiments, the copper foil substrate C may only include one advanced reverse electrolytic copper foil 2.

In order to reduce insertion loss (insertion loss), the substrate 1 may be formed of a material with a low dissipation factor (Df); the Df of the substrate 1 at a frequency of 10 gigahertz (GHz) may be less than or equal to 0.015, preferably less than or equal to 0.010, and more preferably 0.005 or less.

Furthermore, the substrate 1 is formed of a resin-based composite material (ie, prepreg), which is a composite material formed by impregnating a substrate in a synthetic resin and then curing. Specific examples of the substrate include phenolic cotton paper, cotton paper, resin fiber cloth, resin fiber non-woven fabric, glass plate, glass woven fabric, or glass non-woven fabric; specific examples of synthetic resin include epoxy resin, polyester resin, and polyamide Imine resin, cyanate ester resin, bismaleimide triazine resin, polyphenylene ether resin, or phenol resin, and the synthetic resin may form a single-layer or multi-layer structure. Resin-based composite materials can use medium-loss, low-loss, very low-loss, or ultra-low-loss materials. The above terms are well known to those skilled in the art. Specifically, the following commercially available products can be cited: EM890, EM890(K), EM891 (K), EM528, EM526, IT170GRA1, IT958G, IT968G, IT150DA, S7040G, S7439G, S6GX, TU863(+), TU883(A, SP), MEGTRON 4, MEGTRON 6, MEGTRON 7 and MEGTRON 8. However, the above-mentioned example is only one of the feasible embodiments and is not intended to limit the present invention.

2 and 3, the micro-roughened surface 20 of the advanced reverse electrolytic copper foil 2 is formed by electrodeposited copper micro-roughening treatment; it is worth mentioning that the micro-roughened surface 20 has more The copper crystals 21, the copper whiskers W, and the copper crystal clusters G are distributed non-uniformly, that is, they are non-uniformly deposited on the surface of the copper foil. Each copper whisker W is formed by stacking two or more copper crystals 21, and different numbers of copper crystals 21 are stacked together to form respective copper whiskers W, wherein each copper whisker W has a cone The top copper crystal 211 in a shape, rod shape, or spherical shape is preferably spherical. Each copper crystal group G is formed by agglomeration of two or more copper whiskers W, and different numbers of copper whiskers W agglomerate together to form respective copper crystal groups G.

In some embodiments, the average height of the plurality of copper whiskers W may be less than 3 microns, preferably less than 1.8 microns, and more preferably less than 1.0 microns; in addition, the average height of the plurality of copper crystal groups G may be less than 3.5 microns, It is preferably less than 1.8 micrometers, and more preferably less than 1.0 micrometers. In some embodiments, each copper whisker W may include up to 25 copper crystals 21, preferably up to 12 copper crystals 21, more preferably up to 10 copper crystals 21, and particularly preferably up to 8 copper crystals 21 . In some embodiments, the average outer diameter of the plurality of copper crystals 21 may be less than 0.5 micrometers, preferably 0.05 to 0.5 micrometers, and more preferably 0.1 to 0.4 micrometers.

It is worth mentioning that, different from the existing electrolytic copper foil, a plurality of copper crystals are evenly distributed on the surface of the copper foil, and only a small part are gathered together; the advanced reverse electrolytic copper foil 2 of the present invention On the surface, in addition to the multiple copper crystals 21 with non-uniform distribution, there are multiple copper whiskers W formed by different numbers of copper crystals 21 and copper crystals formed by different numbers of copper whiskers W. Group G makes the surface morphology of the copper foil obvious concave and convex. Thereby, the advanced reverse electrolytic copper foil 2 of the present invention can improve signal integrity and suppress insertion loss while maintaining good peel strength, so as to adapt to the high frequency and high speed of signal transmission. In addition, the surface roughness (Rz jis) of the micro-roughened surface 20 is less than or equal to 2.1 micrometers, which contributes to the reduction of the line width and line pitch.

As shown in FIG. 3, the micro-roughened surface 20 further includes a plurality of convex peaks 22 and a plurality of grooves 23 located between the convex peaks 22, and a plurality of copper crystals 21, a plurality of copper whiskers W, and a plurality of copper The crystal cluster G is formed on the plurality of convex peaks 22 correspondingly. Wherein, each groove 23 has a U-shaped or V-shaped cross-sectional profile. When pressing the advanced electrolytic copper foil 2 of the present invention to a resin-based composite material, the micro-roughened surface 20 can receive more resin materials to increase the bonding force between the copper foil and the substrate.

[Preparation example]

Referring again to FIG. 2 and in conjunction with FIG. 4, the preparation method of the advanced reverse electrolytic copper foil 2 of the present invention may be to perform copper electroplating micro-roughening treatment on the matte side of the raw foil. Obtained, the processed bright surface forms the micro-roughened surface 20. Electroplating copper micro-roughening treatment can be carried out with conventional equipment, such as continuous electrolysis equipment or batch electrolysis equipment, and production at a production speed of 5 m/min to 20 m/min and 20 ^o C to 60 ^o C Temperature and predetermined current density to achieve. It is worth mentioning that a steel brush can also be used in advance to carve scratches on the dark surface of the raw foil, so as to form a non-oriented groove with a long island pattern, but it is not limited to this. In some embodiments, the shiny side of the green foil may be subjected to copper electroplating micro-roughening treatment to form the micro-roughening treatment surface 20. The conditions of the electroplated copper micro-roughening treatment are shown in Table 1.

Referring to Figure 4, in this preparation example, the processing equipment used is a continuous electrolysis equipment 3, which includes a feed roller 31, a take-up roller 32, a plurality of electrolytic tanks 33, a plurality of electrolytic roller groups 34 and A plurality of auxiliary roller groups 35; a plurality of electrolytic tanks 33 are arranged between the feeding roller 31 and the receiving roller 32 to contain copper-containing plating solutions of the same or different formulations, and each electrolytic tank 33 is provided with a set of electrodes 331 (Such as platinum electrodes); a plurality of electrolytic roller groups 34 are respectively arranged above the plurality of electrolytic tanks 33, a plurality of auxiliary roller groups 35 are respectively arranged in a plurality of electrolytic tanks 33, a plurality of electrolytic roller groups 34 and a plurality of auxiliary roller groups 35 can drive the raw foil to pass through the plating solution in multiple electrolytic tanks 33 in sequence at a certain speed; the electrode 331 in each electrolytic tank 33 and the corresponding electrolytic roller set 34 are electrically connected to an external power source (not shown in the figure) Out), used to electrolyze the corresponding plating solution, and add required effects to the copper foil.

In practical applications, the copper-containing electroplating solution contains copper ions, acid, and metal additives. The source of copper ions may be copper sulfate, copper nitrate or a combination thereof. Specific examples of the acid include sulfuric acid, nitric acid, or a combination thereof. Specific examples of metal additives include cobalt, iron, zinc, or a combination thereof. In addition, the copper-containing plating solution can be further added with conventional additives as required, such as gelatin, organic nitrogen compounds, hydroxyethyl cellulose (HEC), polyethylene glycol (Poly(ethylene glycol), PEG) , Sodium 3-mercaptopropanesulphonate (MPS), Bis-(sodium sulfopropyl)-disulfide (SPS), or thiourea-based compounds. However, the above-mentioned example is only one of the feasible implementation manners, and is not intended to limit the present invention.

It is worth mentioning that the aforementioned electroplated copper micro-roughening treatment can not only be used for the production of inverted copper foil, but also can be used for High Temperature Elongation (HTE) copper foil or Very Low Profile (Very Low Profile, VLP) production of copper foil.

[Performance Evaluation 1]

Example 1 is the advanced reverse electrolytic copper foil with long island-like microstructures of the present invention (for convenience of description, hereinafter referred to as "long island-like microstructure copper foil" or "ULVLP copper foil"), which is obtained by the aforementioned electroplating copper It is obtained by micro-roughening treatment, the preparation conditions of each stage are shown in Table 1 below, and the surface morphology of the copper foil is shown in Figs. 5, 6 and 7. Figure 5, Figure 6 and Figure 7 are all captured using Hitachi S-3400N Scanning Electron Microscope (SEM) at an inclination angle of 35 degrees; Figure 5 is an SEM image with a magnification of 1,000 times, and Figure 6 is a magnification of 3,000. SEM image of 10,000 times magnification, and Figure 7 is an SEM image of 10,000 times magnification.

Table 1 Plating bath conditions The first plating Second plating Third plating Fourth plating Fifth plating Sixth plating Seventh plating The first trace metal plating Second trace metal plating The third trace metal plating Silane Metal ion Cu ⁺² Cu ⁺² Cu ⁺² Cu ⁺² Cu ⁺² Cu ⁺² Cu ⁺² Ni ⁺² Zn ⁺² Cr ⁺⁶ N/A Metal concentration (g/L) 5.0~10 66~80 66~80 5.0~10 5.0~10 66~80 66~80 17~20 2~4 1~3 N/A Chlorine (ppm) >3 >3 >3 >3 >3 >3 >3 >3 >3 >3 >3 Acid concentration (g/L) Sulfuric acid 90~100 Sulfuric acid 60~75 Sulfuric acid 60~75 Sulfuric acid 90~100 Sulfuric acid 90~100 Sulfuric acid 60~75 Sulfuric acid 60~75 Phosphoric acid 3~6 Boric acid 10~25 Phosphoric acid 0.1~2.0 N/A Trace metals (Ni, Pd, Ag, W ….) (ppm or mg/L) 180~220 30~40 30~40 180~220 180~220 30~40 30~40 100~200 100~200 100~200 N/A Time (Sec) 1.69 2.06 2.06 1.69 1.69 2.06 2.06 2.25 2.06 2.25 3 Temperature (℃)(±5℃) 30 45 45 30 30 45 45 28 30 40 40 PH >1.5 >1.5 >1.5 >1.5 >1.5 >1.5 >1.5 3~4 4~5 3~4 5~7 Example 1 Current density (A/dm ² ) (±10%) 0.01 13.37 13.37 21.24 21.24 4.01 0.01 1.1 0.6 0.6 N/A Example 2 Current density (A/dm ² ) (±10%) 0.01 15.00 15.00 16.00 16.00 4.01 0.01 1.1 0.6 0.6 N/A

It can be seen from FIGS. 5 and 6 that, in the inverted copper foil of Example 1, a plurality of copper crystals 21, copper whiskers W and copper crystal clusters G form a long island pattern with undulations. In addition, it can be seen from FIG. 7 that the micro-roughened surface of the long island-like microstructured copper foil of Example 1 has the following structural characteristics: (1) At least ten first smooth surfaces with a length of 250 nm and a width of 250 nm Area 20a, the area of the first smooth area 20a is equivalent to 250 nm × 250 nm; (2) At least one second smooth area 20b with a length of 500 nm and a width of 500 nm, the area of the second smooth area 20b is equivalent to 500 nm × 500 nm; (3) at least one long island-like microstructure 20c with a length of 1,500 nm or more, and there are at least three copper crystals and/or copper whiskers in the long island-like microstructure 20c; and (4) at least Two linear copper-free areas 20d with a length of 1,000 nm or more. Structural features (1) and (2) help reduce the surface area of copper foil.

It should be noted that the above structural features are used to observe the copper with a scanning electron microscope (SEM, model: Hitachi S-3400N), and an oblique angle of 35 degrees and an appropriate magnification (if the magnification is not specified, it means 10,000 times). The results obtained after the surface morphology of the foil, in which the area size corresponding to the electron microscope irradiation is about 12.7 μm×9.46 μm, which is close to 120 μm ² ; the terms "first smooth region 20a" and "second smooth region 20b" are It refers to the area where no copper crystal exists under the observation of SEM; the term "long island-like microstructure 20c" refers to a structure with a contour shape close to an island or peninsula under SEM observation, and there are many smooth areas around it; the term " Line-shaped copper-free area 20d" refers to an area with no copper crystals and a width of less than 1/3 of the length (which can be linear or non-linear), such as 1/10, 1/100, or 1/1000, which It can be linear or non-linear and can have a uniform or non-uniform width.

The ULVLP copper foil of Example 1 and different types of prepregs were used to make a copper foil substrate, and the insertion loss value was tested. The results are shown in Table 2 below.

Table 2 Prepreg Test method (INTEL) Delta-L PCIe-PCB material and insertion loss target (refer to the target set by Intel) Types of Df Electrical items Insertion loss at 4 GHz (dB/in) Insertion loss at 8 GHz (dB/in) Insertion loss at 12.89 GHz (dB/in) Insertion loss at 16 GHz (dB/in) Medium loss 0.015~0.010 Stripline -0.65 -1.16 -1.74 -2.30 Low loss 0.015~0.005 Stripline -0.50 -0.85 -1.25 -1.49 Ultra low loss 0.005~0.0005 Stripline -0.35 -0.58 -0.83 -0.96

[Test Example 1]

The ULVLP copper foil of Example 1 and Example 2, the reverse electrolytic copper foil according to Taiwan Patent Application No. 107133827 (model: RG311, hereinafter referred to as RG311 copper foil) and the reverse electrolytic copper foil produced by C company ( Model: RTF-3, hereinafter referred to as RTF-3 copper foil), which are respectively bonded with the Mid-loss prepreg material (model: IT170GRA1) produced by I company and cured to form their own single-layer copper foil substrate . Among them, the surface roughness (Rz jis94) of RG311 copper foil is less than 2.3 microns. The surface morphology of the RTF-3 copper foil is shown in Figure 8. It was taken using a scanning electron microscope (model: Hitachi S-3400N) with an inclination angle of 35 degrees and a magnification of 10000 times. The copper crystals are obviously Evenly distributed on the surface of the copper foil. The peel strength of all single-layer copper foil substrates meets the requirements for use, and the Delta L test method proposed by Intel is used for signal integrity at 3 mils Core (1 oz), 10 mils PP and 4.5 mils Trace Width The test results are shown in Table 3 below.

Table 3 Signal integrity test material Df grade Dk@10 GHz RC 50% Df@10 GHz RC 50% Copper foil grade Copper Model SL Loss (dB/in) Take comparison 1 as a benchmark 8 GHz 16 GHz 8 GHz 16 GHz IT-170GRA1 Mid Loss 3.90 0.0100 Comparative example 1 RTF-3 -0.9395 -1.7694 0.00% 0.00% Comparative example 2 RG-311 -0.8321 -1.4986 11.43% 15.30% Example 1 ULVLP -0.7839 -1.4022 16.56% 20.75% Example 2 ULVLP -0.7418 -1.3380 21.04% 24.38%

It can be seen from the test results in Table 3 that at a frequency of 8 GHz, the insertion loss of ULVLP copper foil is reduced by about 16%~21% compared with the insertion loss of RTF-3 copper foil, and compared with the insertion loss of RG311 copper foil Reduced by about 5%~10%; at the frequency of 16 GHz, the insertion loss of ULVLP copper foil is reduced by about 20%~24% compared with the insertion loss of RTF-3 copper foil, and the insertion loss of RG311 copper foil is reduced About 6%~10%. Therefore, ULVLP copper foil has better signal integrity than RTF-3 copper foil and RG311 copper foil.

[Test Example 2]

The ULVLP copper foil of Example 1 and Example 2, the reverse electrolytic copper foil according to Taiwan Patent Application No. 107133827 (model: RG311, hereinafter referred to as RG311 copper foil) and the reverse electrolytic copper foil produced by C company ( Model: RTF-3, hereinafter referred to as RTF-3 copper foil), respectively and the low-loss prepreg material (model: IT958G) produced by I company after being bonded and solidified to form their respective single-layer copper foil substrates . Among them, the surface roughness (Rz jis94) of RG311 copper foil is less than 2.3 microns. The surface morphology of the RTF-3 copper foil is shown in Figure 8. It was taken using a scanning electron microscope (model: Hitachi S-3400N) with an inclination angle of 35 degrees and a magnification of 10,000 times. The copper crystals are obviously Evenly distributed on the surface of the copper foil. The peel strength of all single-layer copper foil substrates meets the requirements for use, and the Delta L test method proposed by Intel is used for signal integrity at 3 mils Core (1 oz), 10 mils PP and 4.5 mils Trace Width The test results are shown in Table 4 below.

Table 4 Signal integrity test material Df grade Dk@10 GHz RC 50% Df@10 GHz RC 50% Copper foil grade Copper Model SL Loss (dB/in) Take comparison 1 as a benchmark 8 GHz 16 GHz 8 GHz 16 GHz IT-958G Low Loss 3.70 0.0070 Comparative example 1 RTF-3 -0.7906 -1.4491 0.00% 0.00% Comparative example 2 RG-311 -0.6996 -1.2415 11.51% 14.33% Example 1 ULVLP -0.6657 -1.1838 15.80% 18.31% Example 2 ULVLP -0.6283 -1.1063 20.53% 23.66%

From the test results in Table 4, it can be seen that

At the frequency of 8 GHz, the insertion loss of ULVLP copper foil is reduced by about 15.80%~20.53% compared with the insertion loss of RTF-3 copper foil, and by about 3%~9% compared with the insertion loss of RG311 copper foil; At a frequency of 16 GHz, the insertion loss of ULVLP copper foil is reduced by about 18% to 23% compared with the insertion loss of RTF-3 copper foil, and the insertion loss of RG311 copper foil is reduced by about ??. Therefore, ULVLP copper foil has better signal integrity than RTF-3 copper foil and RG311 copper foil.

[Test Example 3]

The ULVLP copper foil of Example 1 and Example 2, the reverse electrolytic copper foil (model: RG311, hereinafter referred to as RG311) according to Taiwan Patent Application No. 107133827 and the electrolytic copper foil produced by M company (model: HS1- M2-VSP, hereinafter referred to as HS1-M2-VSP copper foil), respectively use the ultra low-loss prepreg material (model: IT968) produced by I company to form a single-layer copper foil after being laminated and solidified Substrate. Among them, the surface roughness (Rz jis94) of RG311 is less than 2.3 microns. The peel strength of all single-layer copper foil substrates meets the requirements for use, and the Delta L test method proposed by Intel is used for signal integrity at 3 mils Core (1 oz), 10 mils PP and 4.5 mils Trace Width The test results are shown in Table 5 below.

Table 5 Signal integrity test material Df grade Dk@10 GHz RC 50% Df@10 GHz RC 50% Copper foil grade Copper Model SL Loss (dB/in) Take comparison 1 as a benchmark 8 GHz 16 GHz 8 GHz 16 GHz IT-968 Ultra Low 3.66 0.0050 Comparative example 1 HS1-M2-VSP -0.6013 -1.0403 0.00% 0.00% Comparative example 2 RG-311 -0.5489 -0.9208 8.71% 11.49% Example 1 ULVLP -0.5209 -0.8667 13.37% 16.69% Example 2 ULVLP -0.4927 -0.8202 18.06% 21.06%

It can be seen from the test results in Table 5 that at a frequency of 8 GHz, the insertion loss of ULVLP copper foil is reduced by about 16.04%~19.73% compared with the insertion loss of HS1-M2-VSP copper foil, which is comparable to the insertion loss of RG311 copper foil. The ratio is reduced by about 5%~10%; at the frequency of 16 GHz, the insertion loss of ULVLP copper foil is reduced by about 16%~21% compared with the insertion loss of HS1-M2-VSP copper foil, which is compared with the insertion loss of RG311 Reduce by about 5%~10%. Therefore, ULVLP copper foil has better signal integrity than RG311 copper foil and HS1-M2-VSP copper foil.

[Beneficial effects of the embodiment]

One of the beneficial effects of the present invention is that the advanced inverted copper foil with a long island-like microstructure of the present invention can have at least ten copper crystals with a plurality of non-uniformly distributed copper crystals on the micro-roughened surface. A first smooth region with a length of 250 nm and a width of 250 nm, at least one second smooth region with a length of 500 nm and a width of 500 nm, and at least one long island-like microstructure with a length of 1,500 nm or more, and a long island-like microstructure There are at least three "copper crystals and/or copper whiskers" technical means to reduce insertion loss and improve signal integrity without compromising the peel strength, so as to adapt to the high frequency, High speed to meet the needs of 5G applications.

It is worth mentioning that the present invention adopts technical means that have been abandoned due to "technical bias" to some extent, even if the surface of the copper foil has a certain degree of unevenness, and this technical means directly produces good peel strength and maintains good peel strength. The beneficial technical effect of further optimizing the electrical characteristics.

The content disclosed above is only the preferred and feasible embodiments of the present invention, and does not limit the scope of the patent application of the present invention. Therefore, all equivalent technical changes made using the description and schematic content of the present invention are included in the application of the present invention. Within the scope of the patent.

C: Copper foil substrate 1: substrate 2: Advanced electrolytic copper foil 20: Micro-roughened surface 20a: The first smooth area 20b: Second smooth area 20c: Long island-like microstructure 20d: Line-shaped copper-free area 21: Copper Crystal 211: Top Copper Crystal W: Copper whisker G: Copper crystal group 22: convex peak 23: Groove 3: Continuous electrolysis equipment 31: Feeding roller 32: Receiving roller 33: Electrolyzer 331: Electrode 34: Electrolytic roller set 35: auxiliary roller group

Fig. 1 is a schematic diagram of the structure of the copper foil substrate of the present invention.

Fig. 2 is an enlarged schematic diagram of part II of Fig. 1.

Fig. 3 is an enlarged schematic diagram of part III of Fig. 2.

Fig. 4 is a schematic structural diagram of a continuous electrolytic device for producing advanced reverse electrolytic copper foil with a long island-shaped microstructure of the present invention.

Fig. 5 is a scanning electron microscope image obtained by observation at a magnification of 1000 times, which shows the surface morphology of the advanced inverted electrolytic copper foil with a long island-like microstructure of the present invention.

6 is a scanning electron microscope image obtained by observation at a magnification of 3000 times, which shows the surface morphology of the advanced inverted electrolytic copper foil with a long island-like microstructure of the present invention.

FIG. 7 is a scanning electron microscope image obtained by observation at a magnification of 10000 times, which shows the surface morphology of the advanced inverted electrolytic copper foil with a long island-like microstructure of the present invention.

Figure 8 is a scanning electron microscope image showing the surface morphology of the existing RTF-3 copper foil.

FIG. 9 is a scanning electron microscope image, which shows the surface morphology of the existing MLS-G copper foil.

21: Copper Crystal

211: Top Copper Crystal

W: Copper whisker

G: Copper crystal group

22: convex peak

23: Groove

Claims (18)

An advanced inverted electrolytic copper foil with a long island-like microstructure is characterized in that the advanced inverted electrolytic copper foil includes a micro-roughened surface, wherein the micro-roughened surface has a plurality of non-uniform surfaces. Sexually distributed copper crystals; Wherein, different numbers of the copper crystals are stacked together to form respective copper whiskers, and different numbers of the copper whiskers are agglomerated together to form respective copper crystal clusters; Wherein, under the observation of a scanning electron microscope with an inclination angle of 35 degrees and a magnification of 10,000 times, the micro-roughened surface has at least ten first smooth regions with a length of 250 nm and a width of 250 nm and at least one long The second smooth region is 500 nm and the width is 500 nm, and at least one long island-like microstructure with a length of 1,500 nm or more. The advanced inverted electrolytic copper foil with a long island-shaped microstructure according to claim 1, wherein the copper crystals are not present in the first smooth area and the second smooth area. The advanced inverted electrolytic copper foil having a long island-shaped microstructure according to claim 1, wherein, under observation of a scanning electron microscope at an inclination angle of 35 degrees and a magnification of 10,000 times, the long island-shaped microstructure has At least three of the copper crystals and/or the copper whiskers. The advanced reversed electrolytic copper foil with a long island-like microstructure according to claim 1, wherein each of the copper whiskers has a top copper crystal. The advanced inverted electrolytic copper foil with a long island-like microstructure according to claim 4, wherein a plurality of the top copper crystals are in a cone shape, a rod shape, and/or a spherical shape. The advanced reverse electrolytic copper foil with a long island-like microstructure according to claim 1, wherein the micro-roughened surface further has at least two linear copper-free areas with a length of 1,000 nm or more. The advanced reverse electrolytic copper foil with a long island-like microstructure according to claim 1, wherein the surface roughness (Rz jis94) of the micro-roughened surface is less than 2.1 micrometers. The advanced inverted electrolytic copper foil with a long island-shaped microstructure according to claim 1, wherein the micro-roughened surface further includes a plurality of convex peaks and a plurality of grooves located between the plurality of convex peaks , And a plurality of the copper crystals, a plurality of the copper whiskers, and a plurality of the copper crystal clusters are correspondingly formed on the plurality of convex peaks. The advanced reversed electrolytic copper foil with a long island-like microstructure according to claim 1, wherein each of the grooves has a U-shaped or V-shaped cross-sectional topography. A copper foil substrate, which includes: A substrate; and An advanced reverse electrolytic copper foil, which is disposed on the substrate and has a micro-roughened surface bonded to a surface of the substrate, wherein the micro-roughened surface has a plurality of non-uniform distributions的铜晶； Wherein, different numbers of the copper crystals are stacked together to form respective copper whiskers, and different numbers of the copper whiskers are agglomerated together to form respective copper crystal clusters; Wherein, under the observation of a scanning electron microscope with an inclination angle of 35 degrees and a magnification of 10,000 times, the micro-roughened surface has at least ten first smooth regions with a length of 250 nm and a width of 250 nm and at least one long The second smooth region is 500 nm and the width is 500 nm, and at least one long island-like microstructure with a length of 1,500 nm or more. The copper foil substrate according to claim 10, wherein the copper crystal does not exist in the first smooth area and the second smooth area. The copper foil substrate according to claim 10, wherein, under observation with a scanning electron microscope at an inclination angle of 35 degrees and a magnification of 1,000 times, there are at least three copper crystals and/or copper crystals in the long island-shaped microstructure The copper whiskers. The copper foil substrate according to claim 10, wherein each of the copper whiskers has a top copper crystal. The copper foil substrate according to claim 13, wherein a plurality of the top copper crystals have a cone shape, a rod shape, and/or a spherical shape. The copper foil substrate according to claim 10, wherein the micro-roughened surface further has at least two linear copper-free areas with a length of 1,000 nm or more. The copper foil substrate according to claim 10, wherein the surface roughness (Rz jis94) of the micro-roughened surface is less than 2.1 micrometers. The copper foil substrate according to claim 10, wherein the micro-roughened surface further includes a plurality of convex peaks and a plurality of grooves located between the plurality of convex peaks, and a plurality of the copper crystals, One of the copper whiskers and a plurality of the copper crystal clusters are formed on the plurality of convex peaks correspondingly. The copper foil substrate according to claim 17, wherein each of the grooves has a U-shaped or V-shaped cross-sectional profile.

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