KR102655111B1 - Electrodeposited copper foil with its surfaceprepared, process for producing the same and usethereof - Google Patents

Abstract

The present invention relates to a surface-treated electrolytic copper foil manufactured by a foil-making process and a surface treatment process. The surface-treated electrolytic copper foil consists of a base material and a surface protrusion formed on one surface of the base material, and the thickness (b) of the base material is , Characterized in that the protrusion thickness ratio (Y=a/b), which represents the relative ratio to the thickness (a) of the surface protrusion, is 0.15 or more and 0.69 or less.

Description

Surface treated electrolytic copper foil, manufacturing method thereof, and use thereof {ELECTRODEPOSITED COPPER FOIL WITH ITS SURFACEPREPARED, PROCESS FOR PRODUCING THE SAME AND USETHEREOF}

The present invention relates to a surface-treated electrolytic copper foil having an improved dielectric constant, a method of manufacturing the same, and uses of such surface-treated electrolytic copper foil, for example, in printed wiring boards.

Recently, electronic devices such as laptop-sized personal computers are becoming increasingly smaller and lighter. Additionally, IC wiring is becoming more refined. In the wiring patterns formed on the boards used in these electronic devices, lead widths are being refined to dozens of microns (㎛), and the metal foil that forms the wiring patterns is gradually becoming thinner accordingly. In particular, conventionally, the thickness of the metal foil used to form a wiring pattern with a lead width of about 100 ㎛ is about 15 to 35 ㎛ corresponding to the width of the wiring pattern, but the thickness of the metal foil used to form a wiring pattern with a lead width of about 10 ㎛ is also about 15 to 35 ㎛. In response, it needs to become thinner.

For example, aluminum foil, copper foil, etc. are used as metal foils that form such wiring patterns. Among such metal foils, copper foil is preferable, and it is especially preferable to use electrolytic copper foil.

The electrolytic copper foil used to form such a wiring pattern is usually foiled using an electrolytic foiling device as shown in FIG. 1, and roughening or rust prevention treatment to improve adhesion is performed using a surface treatment device as shown in FIG. 2.

The electrolytic thinning device shown in Figure 1 consists of a rotating drum-shaped cathode 2 (the surface is made of SUS or titanium) and an anode 1 (zinc or precious metal oxide-coated titanium electrode) arranged concentrically with respect to the cathode. Then, an electric current is passed between the anodes while the electrolyte solution 3 is flowing, copper is deposited to a predetermined thickness on the surface of the cathode, and then the copper is peeled off in the form of a metal foil from the surface of the cathode. The copper foil 4 at this stage is untreated copper foil. Additionally, the side of the untreated copper foil that is in contact with the electrolyte is the matte side, and the side that is in contact with the rotating drum-shaped cathode 2 is the shiny side.

It is necessary to increase the adhesive strength (peel strength) of the rolled untreated copper foil 4 in order to manufacture a copper clad laminate by laminating it with an insulating substrate. In that respect, electrochemical or chemical surface treatment is continuously performed using a surface treatment device as shown in FIG. 2. Figure 2 shows a device that continuously performs electrochemical surface treatment, in which untreated copper foil (4) is continuously passed through an electrolytic cell filled with electrolyte solution (5) and an electrolytic cell filled with electrolyte solution (5) to form electrodes (7). ) is used as an anode and the copper foil itself is used as a cathode to perform surface treatment, and copper in the form of particles is deposited on the surface of the untreated copper foil (4) to increase adhesion to the insulating substrate (resin film). This process is a roughening treatment process, and the roughening treatment is usually performed on the matte side or shiny side of the untreated copper foil 4. The copper foil after performing these surface treatments is surface-treated copper foil (8), and is made into a circuit board by laminating it with an insulating substrate.

The surface condition of the shiny side of the untreated copper foil 4 is approximately the same as the drum surface condition. In other words, the 10-point average surface roughness (Rz) of the drum is approximately 1.2 to 2.5㎛, and the 10-point average surface roughness (Rz) of the shiny surface is approximately similar.

Meanwhile, the surface roughness of the mat surface varies depending on the state and thickness of copper precipitation, but the surface roughness of the mat surface is greater than that of the shiny surface, and the 10-point average surface roughness (Rz) is generally about 2.5 to 10 μm. Conventionally, in electrolytic copper foil with an average thickness of about 35㎛, it was rare for the surface roughness of the mat surface to be a problem, but in electrolytic copper foil with a thickness of more than 10㎛, the surface roughness of the mat surface is equivalent to several tens of% of the entire thickness of the electrolytic copper foil, The condition of this mat surface has a great influence on the formed wiring pattern, especially the electrical characteristics of the board itself.

In particular, depending on the size or shape of the protrusions deposited on the mat surface of the surface-treated copper foil, differences occur in the surface roughness, color, and gloss of the electrolytic copper foil, and the tensile strength, elongation, and peel strength of the electrolytic copper foil vary. Conventionally, the size and shape of these mat surface protrusions were expressed by physical parameters called surface roughness (e.g., Rz, Ra, Rmax, Rpc, etc.) (see Patent Document 1, Patent Document 2, and Patent Document 3), but Figure 3a and As shown in Figure 3b, there were many areas that could not be measured by existing contact or non-contact illuminance meters. Because of this, the surface roughness value of the existing mat surface had limitations in sufficiently expressing the physical and chemical characteristics of the mat surface of the surface-treated copper foil.

Meanwhile, referring to FIG. 4, even if the electrolytic copper foil 10 has the same thickness and has the same amount of electrodeposition, the thickness of the finished electrolytic copper foil is determined according to the relative ratio of the pattern of the protrusions 12 on the mat surface formed on the surface of the base portion 11 of the electrolytic copper foil. Electrical properties such as tensile strength, bending resistance, peel strength, and dielectric constant can vary significantly.

KR 10-1129471 B1 KR 10-2015-0014850 A KR 10-1090199 B1

The present inventors have found that the physical properties such as tensile strength, bending resistance, and peel strength and the dielectric constant and It was found that the same electrical characteristics were greatly different.

Therefore, the purpose of the present invention is to provide an electrolytic copper foil with excellent physical properties such as tensile strength, bending resistance, and peel strength and electrical properties such as dielectric constant, and a copper clad laminate and printed wiring board using the electrolytic copper foil.

Another purpose of the present invention is to provide an electrolytic copper foil with an optimized relative ratio (Y=a/b) of the mat surface protrusions 12 to the base portion 11 of the surface-treated electrolytic copper foil and a method for manufacturing such electrolytic copper foil. do.

In addition, the present invention provides an electrolytic copper foil in which the relative ratio (Y=a/b) of the mat surface protrusion 12 to the base portion 11 of the surface-treated electrolytic copper foil is optimized, and a copper clad laminate and a printed wiring board using the electrolytic copper foil. It is for another purpose.

The technical problem to be achieved by the present invention is not limited to the above-mentioned problem, and other technical problems not mentioned above can be clearly understood by those skilled in the art from the description of the invention described below.

The surface-treated electrolytic copper foil manufactured by the foil-making process and the surface treatment process according to one aspect of the present invention for achieving the above-described technical problem consists of a base material and a surface protrusion formed on one surface of the base material, It is characterized in that the protrusion thickness ratio (Y=a/b), which represents the relative ratio of the thickness (b) to the thickness (a) of the surface protrusion, is 0.15 or more and 0.69 or less.

The surface protrusions include a surface protrusion layer formed on one surface of the substrate through a foil manufacturing process and a surface treatment layer formed on the surface protrusion layer through a surface treatment process.

The thickness (a) of the surface protrusion is 2 to 8 μm (more preferably, 2.1 to 7.8 μm), and the thickness (b) of the base portion is 10 to 14 μm (more preferably, 10.4 to 13.8 μm). .

One surface of the substrate is a mat surface, and the surface roughness of this mat surface is 1.8 to 4.6 μm with a 10-point average roughness Rz.

The surface treatment process includes a roughening treatment process to form a surface treatment layer on the surface protrusion layer.

A copper clad laminate in which polyimide resin is attached to the surface treatment layer of the surface-treated electrolytic copper foil according to one aspect of the present invention and a printed wiring board on which a circuit pattern is formed on the copper clad laminate are one use of the surface-treated electrolytic copper foil according to one aspect of the present invention. corresponds to

A method of manufacturing a surface-treated electrolytic copper foil according to another aspect of the present invention includes (a) anionic additive 6 as an additive in an aqueous copper sulfate solution having a copper concentration of 60 g/L to 120 g/L and a sulfuric acid concentration of 50 g/L to 120 g/L; ~ 18 ppm and a leveler of 0.1 ~ 4.5 ppm are added to prepare an electrolyte with a TOC concentration of 3 ~ 18 ppm, the electrolyte temperature of this electrolyte is set to 40 ℃ to 60 ℃, and the current density is set to 50 ASD to 80 ASD to the drum surface of the rice maker. manufacturing an untreated copper foil consisting of a substrate and a surface protrusion layer by electrodepositing copper (Cu); And (b) forming a surface treatment layer by a roughening process on the surface protrusion layer of the untreated copper foil to produce a surface-treated electrolytic copper foil; Characterized in that the protrusion thickness ratio (Y=a/b), which represents the relative ratio between the thickness (b) of the substrate and the thickness (a) of the surface protrusion consisting of the surface protrusion layer and the surface treatment layer, is 0.15 or more and 0.69 or less. do.

The anionic additive includes one or more of Cl, F, Br, I, and PO4. Preferably, the anionic additive is Cl, and 7.3 to 16.2 ppm of Cl is added to the electrolyte solution.

Additionally, the leveler includes one or more of gelatin, collagen, and PEG (polyethylene glycol). Preferably, the leveler is gelatin, and 0.5 to 3.4 ppm of gelatin is added to the electrolyte solution.

In addition, the surface-treated electrolytic copper foil according to another aspect of the present invention includes 6 to 18 ppm of an anionic additive as an additive in an aqueous copper sulfate solution having a copper concentration of 60 g/L to 120 g/L and a sulfuric acid concentration of 50 g/L to 120 g/L, Add a leveler of 0.1 to 4.5 ppm to prepare an electrolyte with a TOC concentration of 3 to 18 ppm, set the electrolysis temperature of this electrolyte to 40℃ to 60℃, and set the current density to 50ASD to 80ASD to deposit copper ( It is manufactured by electrodepositing Cu) to produce an untreated copper foil consisting of a base material and a surface protrusion layer, and then forming a surface treatment layer through a roughening process on the surface protrusion layer of the untreated copper foil. The thickness (b) of the base material is And, the protrusion thickness ratio (Y=a/b), which represents the relative ratio to the thickness (a) of the surface protrusion consisting of the surface protrusion layer and the surface treatment layer, is 0.15 or more and 0.69 or less.

The surface-treated electrolytic copper foil according to the present invention not only has excellent physical properties such as tensile strength, bending resistance, and peel strength, but also has excellent electrical properties, such as reduced loss due to signal transmission due to its low dielectric constant. Therefore, the surface-treated electrolytic copper foil according to the present invention is suitable for use as a working laminate for printed wiring boards of electronic devices that are becoming smaller, lighter, and have finer IC wiring.

In addition, the surface-treated electrolytic copper foil according to the present invention can be effectively applied as a negative electrode current collector for lithium secondary batteries due to its excellent physical and electrical properties.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the invention described later, so the present invention includes the matters described in such drawings. It should not be interpreted as limited to only .
1 is a schematic cross-sectional view of a foil-making device for electrodepositing untreated electrolytic copper foil.
FIG. 2 is a schematic cross-sectional view of an embodiment of a surface treatment device for surface treating untreated copper foil manufactured by the making device of FIG. 1.
Figures 3a and 3b are SEM cross-sectional photographs of protrusions formed on the surface of surface-treated electrolytic copper foil.
Figure 4 is a schematic cross-sectional view of a typical surface-treated electrolytic copper foil.
Figure 5 is a schematic cross-sectional view of a surface-treated electrolytic copper foil according to an embodiment of the present invention.
Figure 6 is another schematic cross-sectional view of a surface-treated electrolytic copper foil according to an embodiment of the present invention.
Figure 7 is a schematic cross-sectional view of a dielectric constant measurement device.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms or words used in this specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor should appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle of definability. Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, so at the time of filing the present application, various options that can replace them are available. It should be understood that equivalents and variations may exist.

First, a surface-treated electrolytic copper foil according to an embodiment of the present invention will be described with reference to FIG. 5. Figure 5 is a schematic cross-sectional view of a surface-treated electrolytic copper foil 21 according to an embodiment of the present invention.

As shown in FIG. 5, the surface-treated electrolytic copper foil 21 according to the present invention consists of a raw foil produced by the foil making device of FIG. 1 and a surface treatment layer formed on one side (for example, a mat surface) of the raw foil. . The raw foil is an untreated copper foil produced by the making device of Figure 1. The side of the untreated copper foil in contact with the electrolyte is the matte side, and the side in contact with the rotating drum-shaped cathode is the shiny side. .

The untreated copper foil of FIG. 5 is composed of a base material 22 formed by precipitating copper to a predetermined thickness and a surface protrusion layer 24 formed on one surface (for example, a mat surface) of the base material. On this surface protrusion layer 24, a surface treatment layer 25 is formed again through the surface treatment device of FIG. 2, thereby completing the surface treatment electrolytic copper foil 21 according to one embodiment of the present invention.

Therefore, the surface-treated electrolytic copper foil 21 according to an embodiment of the present invention includes a substrate 22 and a surface protrusion 23 composed of a surface protrusion layer 24 and a surface treatment layer 25 on the substrate 22. It is composed.

At this time, if the thickness of the base material 22 is b and the thickness of the surface protrusion 23 is a, as shown in Figure 5, the surface-treated electrolytic copper foil 21 according to an embodiment of the present invention has a thickness (b) of the base material. The protrusion thickness ratio (Y=a/b), which is a parameter representing the relative ratio of the thickness (a) of the surface protrusion 23 to , is characterized in that it has a numerical range of 0.15 or more and 0.69 or less.

When the thickness ratio of the protrusions (Y = a/b) is less than 0.15, the surface roughness of the surface-treated electrolytic copper foil is excessively lowered, so that a base film (for example, a polyimide film) laminated on the surface-treated electrolytic copper foil to form a printed wiring board ) and the peeling strength decreases. In this case, there is a risk that a de-lamination phenomenon may occur in the printed wiring board.

Additionally, when the protrusion thickness ratio (Y=a/b) exceeds 0.69, the peel strength of the surface-treated electrolytic copper foil is improved, but electrical properties such as dielectric constant and communication loss factor deteriorate.

Therefore, the surface-treated electrolytic copper foil according to an embodiment of the present invention optimizes the protrusion thickness ratio (Y=a/b) to 0.15 to 0.69, thereby achieving the physical properties (particularly, peel strength from the base film) that an electrolytic copper foil for a printed wiring board should have. and electrical properties are significantly improved compared to existing electrolytic copper foil.

In order to implement this protrusion thickness ratio (Y=a/b), the surface-treated electrolytic copper foil according to an embodiment of the present invention has a thickness a of the surface protrusion 23 of 2 to 8 ㎛ (more preferably, 2.1 to 7.8 ㎛). ), and the thickness b of the substrate 22 is manufactured to be 10 to 14 ㎛ (more preferably, 10.4 to 13.8 ㎛).

In addition, the surface roughness of the matte surface of the surface-treated electrolytic copper foil according to an embodiment of the present invention is 1.8 to 4.6 ㎛ as a 10-point average surface roughness Rz.

In addition, the surface treatment layer 25 may be subjected to rust prevention treatment by forming a Cr and/or chromate film, or, if necessary, silane coupling treatment or rust prevention treatment + silane coupling may be performed together.

The thickness b of the base material 22 and the thickness a of the surface protrusion 23, which constitute the protrusion thickness ratio (Y=a/b) according to the present invention, are defined in more detail with reference to FIG. 6.

First, the surface-treated electrolytic copper foil 21 according to an embodiment of the present invention is cut in the MD (Machine Direction) direction by ion milling, and then the cut cross-section is observed with an SEM at a magnification of 2 to 10K and the thickness is measured as follows. do.

The thickness of the surface protrusion 23 is defined as a = a(max) - a(min).

At this time, a(max) is defined as the 5-point average value of the highest points among the protrusions of the surface protrusions within the measurement sample section 30um, and a(min) is defined as the 5-point average value of the lowest points among the protrusions of the surface protrusions within the measurement sample section 30um. do.

The thickness b of the substrate 22 is defined as the distance from the shiny surface to the mat surface a (min).

According to another aspect of the present invention, a copper-clad laminate having a structure in which polyimide resin is attached to the surface treatment layer 25 of the surface-treated electrolytic copper foil 21 is provided. Polyimide resin has a similar coefficient of thermal expansion to electrolytic copper foil for stability in IC chip bonding, etc., and has excellent heat resistance.

According to another aspect of the present invention, a printed wiring board is provided, including the copper clad laminate, and having a predetermined circuit pattern formed on the copper clad laminate through an etching process.

<Examples and Comparative Examples>

Below, the characteristics of the present invention will be examined more clearly by manufacturing surface-treated electrolytic copper foils of Examples and Comparative Examples that satisfy the characteristics of the present invention, and comparing the physical properties of the surface-treated electrolytic copper foils of these Examples and Comparative Examples. Do this.

(Manufacture of untreated electrolytic copper foil)

The untreated electrolytic copper foil according to the Examples and Comparative Examples was manufactured using a making machine as shown in FIG. 1, which has a structure including a rotating drum in an electrolytic cell and a positive electrode plate positioned at a predetermined interval with respect to the drum. At this time, the gap between the positive plate and the rotating drum can be adjusted within the range of approximately 5 to 20 mm, and the standard deviation of the gap must be controlled within 2 mm.

Copper sulfate can be used as the electrolyte used in the manufacturing process using such a manufacturing machine, and by using an appropriate mixture of levelers, anion additives, brighteners, etc. as additives, copper foil is electrodeposited on a drum to produce untreated electrolytic copper foil.

At this time, the composition of the copper sulfate electrolyte solution includes 60 to 120 g/L of copper and 50 to 120 g/L of sulfuric acid, and the anion additive includes any one or more of Cl, F, Br, I, and PO ₄ at 6 to 18 ppm ( More preferably, 7.3 to 16.2 ppm) is added, and the leveler adds 0.1 to 4.5 ppm (more preferably, 0.5 to 3.4 ppm) of any one or more of gelatin, collagen, and PEG (polyethylene glycol) to increase TOC ( Total Organic Carbon) concentration is adjusted to 3~18ppm. In addition, the untreated electrolytic copper foil corresponding to the examples is manufactured by manufacturing the electrolytic copper foil under electrolytic conditions in which the current density is in the range of 50 ASD to 80 ASD and the temperature of the electrolyte solution is 40 to 60 ° C. under this electrolyte composition and additive composition.

On the other hand, in order to manufacture the untreated electrolytic copper foil corresponding to the comparative example, a method different from the manufacturing method of the above-described example is applied, specifically, copper sulfate (60 to 120 g/L of copper, 50 g/L) used as an electrolyte in the manufacturing process. An untreated electrolytic copper foil corresponding to the comparative example was manufactured by electrodepositing copper foil with the type and content of additives added in (~ 120 g/L sulfuric acid) different from the examples as shown in [Table 1] below.

The specific composition and electrolysis conditions of the electrolyte and additives for foiling the electrolytic copper foil according to the Examples and Comparative Examples are as follows.

Copper: 85~90g/L

Sulfuric acid: 75~90g/L

Electrolyte temperature: 55℃

Current density: 70~80ASD

Additive type: Cl, gelatin

Additive content: Refer to [Table 1]

Cu
[g/L] H2SO4
[g/L] gelatin
[ppm] Cl
[ppm] TOC
[ppm] current density
[ASD] liquid temperature
[℃] Example 1 85 75 3.4 15.7 18 80 55 Example 2 87 90 0.5 7.3 4 75 55 Example 3 85 85 0.6 16.2 3 80 55 Example 4 86 77 3.2 7.7 18 75 55 Example 5 85 78 0.5 14.8 4 70 55 Example 6 89 83 3.1 7.9 17 70 55 Example 7 90 90 0.7 8.2 4 75 55 Comparative Example 1 88 87 3.3 18.3 19 70 55 Comparative Example 2 85 78 0.2 2.3 2 75 55 Comparative Example 3 85 76 5.8 15 32 80 55 Comparative Example 4 87 79 4.8 24.3 16 70 55

(Manufacture of surface-treated electrolytic copper foil) The untreated electrolytic copper foil of the above-mentioned examples and comparative examples is manufactured into a surface-treated electrolytic copper foil by subjecting it to a surface treatment process through a surface treatment device as shown in FIG. 2.

The surface treatment process is a process of forming ultra-fine copper particles by burning plating on the surface (matte side and shiny side) of the untreated electrolytic copper foil, and performing rust prevention treatment after plan plating to prevent copper particles from falling out. This process creates irregularities on the surface of the untreated electrolytic copper foil. The purpose is to improve the mechanical and chemical bonding strength of the electrolytic copper foil by forming it.

The surface treatment process is performed, for example, as shown in [Table 2] below, but the surface treatment process according to the present invention is not necessarily limited to this example, and various roughening treatments or untreated electrolytic copper foil that form fine copper nodules on the surface of the untreated electrolytic copper foil are used. Of course, various known surface treatment processes can be adopted to improve the physical and/or chemical properties of.

Surface treatment process
T1 process

Current [ASD] 25~30 Temperature [℃] 20~30 Cu concentration [g/L] 10~20 H ₂ SO ₄ Concentration [g/L] 80~120
T2 process

Current [ASD] 5~15 Temperature [℃] 30~50 Cu concentration [g/L] 40~60 H ₂ SO ₄ Concentration [g/L] 80~120

T4 process

Current [ASD] 1~5 Temperature [℃] 20~30 PH 10~11 Ni concentration [g/L] 1~2 Ni film amount [ppm] 5~30

T5 process

Current [ASD] 1~5 Temperature [℃] 20~30 PH 10~11 Zn concentration [g/L] 1~2 Zn film amount [ppm] 5~30

T6 process

Current [ASD] 1~5 Temperature [℃] 20~30 PH 10~11 Cr concentration [g/L] 1~2 Cr film amount [ppm] 1~5 T7 process Silane coupling agent [g/L] 0.1~5 drying process Temperature: 130~250℃, Time: 2~6 seconds

The T1 process in [Table 2] applies a current of 25 to 30 ASD in an electrolyte solution with a Cu concentration of 10 to 20 g/L, a H ₂ SO ₄ concentration of 80 to 120 g/L, and a temperature of 20 to 30 ° C in a burning plating bath to produce untreated electrolytic copper foil. It is a burning plating process that forms ultra-fine copper particles on the surface. At this time, the sealing plating process to capture the generated ultrafine copper particles is the T2 process, and the T2 process is an electrolyte with a Cu concentration of 40 to 60 g/L, H ₂ SO ₄ concentration of 80 to 120 g/L, and a temperature of 30 to 50°C. It is processed by applying a current of 5 to 15 ASD. The T4~T6 process is a process that improves the physical properties such as chemical resistance/acid resistance/oxidation resistance of the copper foil surface by treating the surface with inorganic substances such as Ni, Zn, Cr, etc. The T7 process is a process that improves the chemical bonding power of electrolytic copper foil through treatment with a silane coupling agent. At this time, the preferred silane coupling agent is quaternary amino-based ethoxy or methoxy silane, and the appropriate concentration is 0.1 to 5 g/L to form a film with a thickness of 0.1 to 10 ppm. After treatment with the silane coupling agent, a drying process is performed at 130 to 250° C. for 2 to 6 seconds to obtain samples of the surface-treated electrolytic copper foil according to the examples and comparative examples.

Physical properties such as unit weight, tensile strength, and bending resistance were measured for the untreated electrolytic copper foil samples of Examples and Comparative Examples manufactured through the foil manufacturing process in [Table 1], and manufactured through the surface treatment process in [Table 2]. For the surface-treated electrolytic copper foil samples of Examples and Comparative Examples, the peel strength and dielectric constant were measured, respectively, and are listed in [Table 3] and [Table 4].

Performance evaluation of electrolytic copper foil

1) Measurement of bending resistance

Bending resistance was measured according to JIS-P8115.

2) Peel strength measurement

After attaching a polyimide film to the mat surface side of the surface-treated electrolytic copper foil samples of Examples and Comparative Examples, the peel strength was measured. Measurement of peel strength was performed by peeling in a 180 degree direction according to JIS C6471.

3) Dielectric constant measurement

The dielectric constant was measured according to IPC-TM-650. In other words, create a micro transmission line as shown in Figure 7 and check the signal transmission status. Calculate the amount lost when injecting a microstrip line at a constant frequency compared to Ref. The lower the dielectric constant, the better the signal is transmitted without transmission loss. It is desirable that the dielectric constant of the surface-treated electrolytic copper foil is 4% or less, and if it exceeds 4%, it may cause problems during use.

unit weight
[g/㎡] tensile strength
[kgf/㎟] Flexibility resistance
[MIT count] Example 1 94 33 731 Example 2 96 33 721 Example 3 94 38 772 Example 4 93 39 731 Example 5 94 37 773 Example 6 94 34 691 Example 7 95 35 688 Comparative Example 1 93 40 798 Comparative Example 2 94 44 846 Comparative Example 3 96 26 583 Comparative Example 4 95 24 612

<Comparison of physical properties of untreated electrolytic copper foil> Referring to [Table 3] above, the untreated electrolytic copper foil of Examples 1 to 7 has unit weight, tensile strength (30 kgf/㎟ or more), and bending resistance (MIT count: 680 times or more). While the physical properties required for electrolytic copper foil for printed wiring boards are excellent, the untreated electrolytic copper foil of Comparative Examples 3 and 4 not only had a tensile strength of less than 30 kgf/㎟, but also had a bending resistance of less than 650 MITs. The physical properties are significantly lower than those in the examples.

a
[㎛] b
[㎛] Y
[a/b] unit weight
[g/㎡] Rz
[㎛] Peel strength
[kgf/mm] permittivity
[%] Example 1 7.8 11.3 0.69 104 4.6 1.38 3.80 Example 2 6.3 12.7 0.50 105 4.4 1.29 3.61 Example 3 4.5 13.5 0.33 104 3.3 1.21 3.52 Example 4 4.3 10.4 0.41 107 3.1 1.01 3.60 Example 5 2.1 13.8 0.15 108 2.8 1.09 3.08 Example 6 6.4 11.5 0.56 106 4.1 1.32 3.67 Example 7 5.5 12.9 0.43 107 3.0 1.06 3.63 Comparative Example 1 1.9 14 0.14 108 2.5 0.77 2.87 Comparative Example 2 1.3 10.3 0.13 105 2.2 0.72 2.56 Comparative Example 3 10.6 7.7 1.38 108 8.2 1.57 4.3 Comparative Example 4 10.3 9.0 1.14 108 7.5 1.75 4.15

<Comparison of physical and electrical properties of surface-treated electrolytic copper foil> (a: Thickness of surface protrusion 23, b: Thickness of base material 22, Y (a/b): Protrusion thickness ratio, Rz: Matte surface of surface-treated electrolytic copper foil 10 point average surface roughness)

Referring to [Table 4], the surface-treated electrolytic copper foil of Examples 1 to 7 has a thickness a of the surface protrusion 23 of 2 to 8 ㎛ (more preferably, 2.1 to 7.8 ㎛), and the base material 22 ) has a thickness b of 10 to 14 ㎛ (more preferably, 10.4 to 13.8 ㎛), and the protrusion thickness ratio (Y = a/b) has a numerical range of 0.15 or more and 0.69 or less. For this reason, the surface-treated electrolytic copper foils of Examples 1 to 7 have a relatively low surface roughness Rz of 1.8 ㎛ to 4.6 ㎛, and exhibit excellent peel strength (1.0 Kgf/mm or more) and dielectric constant (4% or less).

On the other hand, the surface-treated electrolytic copper foils of Comparative Examples 1 and 2 had a protrusion thickness ratio (Y=a/b) of less than 0.15, and thus the peel strength was significantly lowered to 1.00Kgf/mm or less. In addition, the surface-treated electrolytic copper foil of Comparative Examples 3 and 4 had a protrusion thickness ratio (Y=a/b) exceeding 0.69, resulting in a dielectric constant of 4% or more, thereby increasing signal transmission loss.

Although the present invention has been described above with limited examples and drawings, the present invention is not limited thereto, and the technical idea of the present invention and the description below will be understood by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalence of the patent claims.

21: Surface treated electrolytic copper foil
22: Description
23: surface protrusion
24: Surface protrusion layer
25: Surface treatment layer

Claims (7)

A surface-treated electrolytic copper foil manufactured by a foil manufacturing process and a surface treatment process,
The surface-treated electrolytic copper foil consists of a base material and a surface protrusion formed on one surface of the base material,
The surface protrusions include a surface protrusion layer formed on one surface of the substrate by the foil manufacturing process and a surface treatment layer formed on the surface protrusion layer by the surface treatment process,
The surface treatment layer includes a nickel (Ni) film in the range of 5 to 30 ppm, a zinc (Zn) film in the range of 5 to 30 ppm, and a chromium (Cr) film in the range of 1 to 5 ppm, stacked in that order,
The protrusion thickness ratio (Y=a/b), which represents the relative ratio between the thickness (b) of the substrate and the thickness (a) of the surface protrusion, is 0.15 or more and 0.69 or less,
One surface of the substrate is a mat surface,
The surface roughness of the mat surface is 2.8 to 4.6 ㎛ as the 10-point average surface roughness Rz,
Surface-treated electrolytic copper foil, characterized in that the dielectric constant is 3.08 to 4.0%. According to claim 1,
A surface-treated electrolytic copper foil, characterized in that the thickness (a) of the surface protrusion is 2 to 8㎛. According to clause 2,
Surface-treated electrolytic copper foil, characterized in that the thickness (a) of the surface protrusion is 2.1 to 7.8 ㎛. According to claim 1,
A surface-treated electrolytic copper foil, characterized in that the thickness (b) of the substrate is 10 to 14 ㎛. According to clause 4,
Surface-treated electrolytic copper foil, characterized in that the thickness (b) of the substrate is 10.4 to 13.8 ㎛. A copper-clad laminate comprising a polyimide resin attached to a surface treatment layer of the surface-treated electrolytic copper foil according to any one of claims 1 to 5. A printed wiring board characterized in that a circuit pattern is formed on the copper clad laminate of claim 6.