WO2014126193A1

WO2014126193A1 - Surface-treated copper foil, and copper-clad laminate obtained using surface-treated copper foil

Info

Publication number: WO2014126193A1
Application number: PCT/JP2014/053450
Authority: WO
Inventors: 裕昭津吉; 眞細川
Original assignee: 三井金属鉱業株式会社
Priority date: 2013-02-14
Filing date: 2014-02-14
Publication date: 2014-08-21
Also published as: CN105102678B; TW201446492A; CN105102678A; CN107881505A; KR20150119217A; TWI543862B; JPWO2014126193A1; KR101574475B1; JP5809361B2

Abstract

The purpose of the present invention is to provide a copper foil provided with better adhesiveness with an insulating resin substrate than that of a non-roughened copper foil, and provided with good etching performance equivalent to that of a non-roughened copper foil. In order to achieve said purpose, a surface-treated copper foil obtained by roughening a surface of the copper foil, or the like, is used, said surface-treated copper foil being characterized in that the surface of the copper foil is provided with a roughened surface roughened by needle-like or plate-like microscopic protrusions and recesses with a maximum length of 500 nm, said microscopic protrusions and recesses comprising a copper composite compound. The copper composite compound is preferably provided with a composition comprising 50% to 99% cuprous oxide, with the remainder comprising copper oxide and impurities.

Description

Surface-treated copper foil and copper-clad laminate obtained by using surface-treated copper foil

This application relates to a surface-treated copper foil and a copper-clad laminate obtained using the surface-treated copper foil. In particular, the present invention relates to a surface-treated copper foil obtained by roughening the surface of a copper foil with needle-like or plate-like fine irregularities made of a copper composite compound.

In general, copper foils that are distributed in the market are often used for circuit formation applications of printed wiring boards, and in order to improve adhesion to insulating resin substrates, anchors are attached to the surface of the copper foil that becomes the adhesive surface. We have provided a roughened shape that demonstrates the effect. As roughening that exhibits this anchor effect, “adhesion of fine copper particles” as disclosed in Patent Document 1 and the like, “unevenness formation by etching” as disclosed in Patent Document 2 and the like are performed. I came.

However, in recent years, the demand for the formation of fine pitch circuits is remarkable, and as a result of great progress in the manufacturing technology of printed wiring boards, the use of non-roughened copper foil as disclosed in Patent Document 3 and Patent Document 4 is used. Has come to be done.

This Patent Document 3 provides a copper-clad laminate for a printed circuit in which a copper foil and a laminated substrate are firmly bonded with a tough and reactive adhesive. Or, in a copper clad laminate having copper foil laminated and bonded on both sides, a. A general formula QRSiXYZ ... [1] (wherein Q is a functional group that reacts with the following resin composition, R is Or a silane coupling agent represented by the general formula T (SH) n, a bonding group for linking Q and Si atoms, and X, Y, and Z are hydrolyzable groups or hydroxyl groups bonded to Si atoms). .. [2] (where T is an aromatic ring, aliphatic ring, heterocyclic ring, aliphatic chain, and n is an integer of 2 or more) through an adhesive base made of a thiol-based coupling agent, b (1) Acrylic monomer, methacrylic monomer, their polymer or oleic Copolymer with fin, (2) peroxide curable resin composition of diallyl phthalate, epoxy acrylate or epoxy methacrylate and oligomer thereof, (3) ethylene butylene copolymer and styrene copolymer in the molecule A thermoplastic elastomer peroxide curable resin composition, (4) an olefin copolymer resin composition containing a glycidyl group, and (5) a polyvinyl butyral resin resin composition having a side chain containing an unsaturated group. Or (6) an adhesive composed of a polyvinyl butyral resin and a resin composition of an amino resin having a spiroacetal ring and an epoxy resin, or an adhesive of the resin composition. Adopting a copper-clad laminate for printed circuits characterized by being directly bonded to the laminated substrate. It has been disclosed.

Patent Document 4 discloses a surface-treated copper that does not contain chromium in the surface treatment layer and is excellent in the peel strength of the circuit after processing into a printed wiring board and the chemical resistance deterioration rate of the peel strength. For the purpose of providing a foil, “a surface-treated copper foil in which a surface-treated layer is provided on a laminated surface of a copper foil used when a copper-clad laminate is produced by laminating with an insulating resin base material, Adopting a surface-treated copper foil obtained by adhering a zinc component to a bonding surface of a copper foil, attaching a high melting point metal component having a melting point of 1400 ° C. or higher, and further adhering a carbon component ”. Among them, it is disclosed that “the bonding surface of the copper foil preferably has a surface roughness (Rzjis) of 2.0 μm or less without being subjected to roughening treatment”. Yes.

Such a non-roughened copper foil does not have irregularities used for roughening on the surface bonded to the insulating resin substrate. For this reason, it is not necessary to provide an over-etching time for removing the anchor shape (uneven shape) embedded in the insulating resin base material when the circuit is formed by etching the copper foil. Therefore, it is very useful in forming a fine pitch circuit having a good etching factor.

JP 05-029740 A JP 2000-282265 A Japanese Patent Application Laid-Open No. 09-074273 JP 2008-297469 A

However, since this non-roughened copper foil does not have an anchor shape (uneven shape) embedded in the insulating resin substrate side, the adhesion of the non-roughened copper foil to the insulating resin substrate is roughened. It tends to be lower than copper foil.

Therefore, in the market, compared with the adhesiveness of the non-roughened copper foil to the insulating resin base material, the non-roughened copper foil has good adhesiveness with the insulating resin base material and has no irregularities used for roughening. There was a need for a copper foil with good etching performance equivalent to.

Therefore, as a result of diligent research by the inventors of the present invention, by adopting the copper foil shown below, there is an anchor shape (uneven shape) embedded in the insulating resin substrate side, so that the insulating resin substrate It was found that good adhesiveness with can be provided. Hereinafter, the surface-treated copper foil according to the present application will be described.

Surface-treated copper foil: The surface-treated copper foil according to the present application is a surface-treated copper foil obtained by roughening the surface of the copper foil. The surface of the copper foil has a needle shape made of a copper composite compound having a maximum length of 500 nm or less. Alternatively, a roughening treatment layer formed of plate-like fine irregularities is provided. In the following, “acicular or plate-like fine irregularities made of a copper composite compound” will be simply referred to as “fine irregularities made of a copper composite compound”.

The fine irregularities made of the copper composite compound of the roughened layer of the surface-treated copper foil according to the present application are obtained by using a scanning electron microscope at a surface angle of the roughened layer at a tilt angle of 45 ° and a magnification of 50000 times or more. The maximum length when observed from is 150 nm or less.

The fine irregularities made of the copper composite compound of the surface-treated copper foil according to the present application are Cu (I) when the total area of each peak area of Cu (I) and Cu (II) when analyzed by XPS is 100%. ) It is preferable that the peak occupation area ratio is 50% or more.

The fine irregularities made of the copper composite compound of the surface-treated copper foil according to the present application contain copper oxide and cuprous oxide.

Moreover, it is preferable that the fine unevenness | corrugation which consists of a copper complex compound of the surface treatment copper foil which concerns on this application has a specific surface area measured by making krypton adsorb | suck 0.035 m < ² > / g or more.

Furthermore, the surface of the roughened layer of the surface-treated copper foil according to the present application, L ^* a ^* b ^* color system of the lightness L ^* is preferably provided with a lightness of 25 or less.

Copper-clad laminate: The copper-clad laminate according to the present application is obtained using the above-mentioned surface-treated copper foil.

The surface-treated copper foil according to the present application forms a roughened surface with “fine irregularities made of a copper composite compound having a maximum length of 500 nm or less”. And although this roughening process surface exists in the outermost surface of copper foil, the macro uneven | corrugated shape of a micrometer order with which the adhesive surface with the insulating resin base material of copper foil is maintained as it is. As a result, it is possible to ensure good adhesion compared to the adhesion of the non-roughened copper foil to the insulating resin substrate.

It is a scanning electron microscope observation image for demonstrating the roughening form of the surface treatment copper foil which concerns on this application (sample for the immersion time of 2 minutes of the oxidation process in Example 1). In the surface-treated copper foil which concerns on this application, it is a scanning electron microscope observation image for showing the roughening form which changes with the roughening object site | parts of the electrode surface and precipitation surface of an electrolytic copper foil (of the oxidation process in Example 1). Sample with an immersion time of 2 minutes). It is a scanning electron microscope observation image of the cross section of the roughening process layer of the surface treatment copper foil which concerns on this application (sample for the immersion time of 2 minutes of the oxidation process in Example 1). It is the scanning electron microscope observation image which looked at the roughening process form of the comparative sample in a comparative example from the surface. It is the scanning electron microscope observation image which looked at the roughening process layer of the comparative sample in a comparative example from the cross section.

Hereinafter, the “form of the surface-treated copper foil” and the “form of the copper-clad laminate” according to the present application will be described.

Form of surface-treated copper foil: The surface-treated copper foil according to the present application is a surface-treated copper foil obtained by roughening the surface of the copper foil. The surface of the copper foil is made of a copper composite compound having a maximum length of 500 nm or less. It is characterized by comprising a roughened layer formed with fine irregularities.

The copper foil used for the production of the surface-treated copper foil according to the present application can be either an electrolytic copper foil or a rolled copper foil. Further, the thickness of the copper foil is not particularly limited, and it is generally sufficient to recognize that the thickness is 200 μm or less. In addition, the surface-treated copper foil according to the present application covers both cases where one side is roughened and both sides are roughened.

The roughened surface of the surface-treated copper foil according to the present application forms a “fine unevenness made of a copper compound” containing copper oxide on the surface of the copper foil, and a reduction treatment is performed to convert cuprous oxide into cuprous oxide. By converting, it is preferable that the surface is roughened by “fine irregularities made of a copper composite compound having a maximum length of 500 nm or less” containing copper oxide and cuprous oxide. Here, “the maximum length is 500 nm or less” indicates the maximum value of “fine irregularities made of a copper composite compound” obtained by observing the roughened surface of the surface-treated copper foil with a field emission type scanning electron microscope. It is a thing. As shown in FIG. 3 to be described later, the maximum value of the shape of the “fine irregularities made of the copper composite compound” is the “roughening treatment layer formed by the fine irregularities made of the copper composite compound” provided on the surface of the copper foil. In the cross section, it is a needle-like or plate-like length extending from the surface of the copper foil. From the viewpoint of enhancing the adhesion between the surface-treated copper foil and the insulating layer constituting material according to the present application, the maximum length is more preferably 400 nm or less, and still more preferably 300 nm or less. Hereinafter, this maximum length may be referred to as “maximum length 1”.

And "the fine unevenness | corrugation which consists of a copper composite compound" which comprises the roughening process layer of the surface treatment copper foil which concerns on this application is a field emission type scanning, as shown in FIG. "Maximum length of fine irregularities made of a copper composite compound" when observed planarly with a scanning electron microscope at a magnification of 50000 times or more (inclination angle of the sample 45 ° when observed with a scanning electron microscope) 150 nm or less is preferable. This FIG. 1 is observed as shown in FIG. 1 (b) when the deposited surface (FIG. 1 (a)) of the double-side smooth electrolytic copper foil is roughened by “fine irregularities made of a copper composite compound” as referred to in the present application. It is shown that. FIG. 1C shows an observation image obtained by further enlarging the surface of FIG. From the viewpoint of enhancing the adhesion between the surface-treated copper foil and the insulating layer constituting material according to the present application, the maximum length is more preferably 100 nm or less. Hereinafter, this maximum length may be referred to as “maximum length 2”.

For example, when the precipitating surface of the electrolytic copper foil shown in FIG. 1 (a) is measured with a non-contact three-dimensional surface shape / roughness measuring machine (model: New-View 6000) manufactured by Zygo Corporation. Ra = 1.6 nm, Rz = 26 nm. The electrolytic copper foil after the roughening treatment shown in FIG. 1 (b) is roughened with respect to the deposited surface of the electrolytic copper foil by “fine irregularities made of a copper composite compound” as referred to in the present application. When this surface is measured in the same manner, Ra = 2.3 nm and Rz = 39 nm, and it can be understood that the surface is roughened in the nm order. Furthermore, in FIG. 2, the roughening form which changes with the site | parts with which the electrode surface of an electrolytic copper foil and a precipitation surface roughen is shown. This FIG. 2 will be described in detail in the embodiment.

FIG. 3 shows a cross section of fine irregularities made of a copper composite compound formed by roughening at this time. In this cross-sectional view, there is a certain variation in the thickness of the roughened layer formed by densely forming fine irregularities made of a copper composite compound, but the average thickness from the surface of the copper foil is 400 nm or less. In FIG. 3, the roughened layer has an average thickness of 250 nm. As a result of many tests conducted by the inventors of the present application, if the average thickness of the roughened layer falls within the range of 100 nm to 350 nm, “the better than the non-roughened copper foil for the insulating resin base material” It is judged that it can have “adhesion”.

Next, regarding the components constituting the fine irregularities made of a copper composite compound, state analysis was attempted using an X-ray photoelectron spectroscopy (hereinafter simply referred to as “XPS”). As a result, the presence of “Cu (0)”, “Cu (II)”, “Cu (I)”, and “—COO group” was confirmed. Here, since the presence of the “—COO group” was confirmed, there is a high possibility that “copper carbonate” is included. Therefore, it is considered that copper carbonate is contained in the impurities contained in the copper composite compound described below.

Then, when the copper composite compound of the surface-treated copper foil according to the present application is analyzed using the above-described XPS, each peak of Cu (I) and Cu (II) can be separated and detected. When the copper composite compound is analyzed by XPS, the Cu (0) peak may be observed in the shoulder portion of the large Cu (I) peak, so the Cu (I) peak including this shoulder portion may be observed. It is considered. Therefore, in the present invention, the copper composite compound is analyzed using XPS, and Cu (I) appearing at 932.4 eV and Cu (II) appearing at 934.3 eV corresponding to the binding energy of Cu 2p 3/2. Each peak obtained by detecting the photoelectrons is separated into waveforms, and the occupied area ratio of the Cu (I) peak is specified from the peak area of each component. The Cu (I) peak at this time is considered to be derived from “monovalent copper constituting cuprous oxide”. And it is thought that a Cu (II) peak originates in "the bivalent copper which comprises copper oxide." Furthermore, it is considered that the Cu (0) peak is derived from “zero-valent copper constituting metallic copper”. In this application, Quantum 2000 (beam condition: 40 W, 200 um diameter) manufactured by ULVAC-PHI Co., Ltd. is used as the XPS analyzer, and “MultiPack ver. 6.1A” is used as the analysis software. Went.

Therefore, in the case of “fine irregularities made of a copper composite compound” of the surface-treated copper foil according to the present application, the total area of each peak area of Cu (I) and Cu (II) when analyzed by XPS is 100%. Sometimes, the occupied area ratio of the Cu (I) peak is preferably 50% or more. When the occupied area ratio of the Cu (I) peak is less than 50%, the roughened surface of the surface-treated copper foil according to the present application is laminated on the insulating layer constituting material, and the resistance of the circuit obtained by forming the circuit is increased. This is not preferable because the chemical performance decreases. Here, the occupied area ratio of the Cu (I) peak of the copper composite compound is more preferably 70% or more, and further preferably 80% or more. Since cuprous oxide has lower acid solubility than copper oxide, the more the Cu (I) peak occupancy ratio increases, the more the etching solution to the intimate contact with the insulating layer constituent material in the etching process during circuit formation. This is because insertion of a plating solution or the like can be reduced and chemical resistance performance is improved. On the other hand, the occupied area ratio of the Cu (I) peak is not particularly limited, but is 99% or less by an oxidation treatment and a reduction treatment described later. However, the lower the occupied area ratio of the Cu (I) peak, the more the adhesion itself with the insulating layer constituting material tends to improve. In order to obtain good oxidation resistance, 98% or less is preferable and 95% or less is preferable. More preferred. It is. The occupied area ratio of the Cu (I) peak is calculated by a calculation formula of Cu (I) / {Cu (I) + Cu (II)} × 100 (%).

And the fine unevenness | corrugation which consists of a copper complex compound formed by the roughening at this time has a specific surface area (henceforth only called "specific surface area") which adsorb | sucked krypton and is 0.035 m < ² > / g or more. It is preferable to satisfy the condition. This is because when the specific surface area is 0.035 m ² / g or more, the average thickness of the roughened layer is on the order of 200 nm, and the adhesion of the non-roughened copper foil to the insulating resin substrate can be exceeded. . Here, although the upper limit of the specific surface area is not defined, the upper limit is about 0.3 m ² / g, more preferably 0.2 m in order to ensure good etching performance equivalent to that of the non-roughened copper foil. ² / g. Note that the specific surface area at this time was pre-treated by heating the sample at 300 ° C. for 2 hours using a specific surface area / pore distribution measuring device 3Flex manufactured by Micromeritics. Measurement is performed using krypton (Kr) as the gas.

Since the above-mentioned “fine irregularities made of a copper composite compound” are fine enough to absorb light, the surface of the roughened layer is darkened such as blackening or browning. That is, the surface of the roughened layer of the surface-treated copper foil according to the present application has a characteristic color tone, and the lightness L ^{* of} the L ^* a ^* b ^* color system is 25 or less, more preferably 20 or less. is there. If the lightness L ^* exceeds 25 and the color tone becomes bright, sufficient roughening has not been performed, and “good adhesion more than unroughened copper foil to an insulating resin base material” can be obtained. Since it is not, it is not preferable. The lightness L ^* was measured using a spectral color difference meter SE2000 manufactured by Nippon Denshoku Industries Co., Ltd., and the whiteness plate attached to the measuring device was used for the lightness calibration in accordance with JIS Z8722: 2000. And the measurement of 3 times is performed regarding the same site | part, and the average value of the measurement data of 3 times lightness L ^* is described as the value of the lightness L ^* of this application.

Then, a method for forming “fine irregularities made of a copper composite compound” used for roughening the surface-treated copper foil according to the present application will be described. And this copper complex compound contains a copper oxide and a cuprous oxide. This copper composite compound is formed as follows. First, the surface of the copper foil is oxidized by a wet method using a solution to form “fine irregularities made of a copper compound” containing copper oxide on the surface of the copper foil. Thereafter, the copper compound is subjected to a reduction treatment to convert a part of the copper oxide into cuprous oxide, thereby obtaining “fine irregularities made of a copper composite compound” containing copper oxide and cuprous oxide. The solution used for the oxidation treatment in the present application is preferably an alkaline solution that hardly erodes copper oxide, and can be dissolved in the alkaline solution and can be relatively stably coexistent with an amino-based silane coupling. It is preferable to use an agent. Therefore, by adding an amino-based silane coupling agent to the solution used for the oxidation treatment, formation of “fine irregularities made of a copper compound” is facilitated. Since the amino silane coupling agent is adsorbed on the surface of the copper foil, the surface of the copper foil is finely suppressed, so that it becomes a shape of “fine irregularities made of a copper compound”. Specific examples of this amino silane coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3- Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, etc. may be used. it can.

And when the above-mentioned oxidation treatment is completed, the fine irregularities made of the copper compound are reduced. `` Fine unevenness made of copper compound '' formed by the oxidation treatment on the surface of the surface-treated copper foil according to the present application, while maintaining the shape of the fine unevenness made of the original copper compound even when the reduction treatment is performed, It becomes “fine irregularities made of a copper composite compound” containing copper oxide and cuprous oxide having a length of the order of nm. If the copper compound of “fine unevenness made of copper compound” obtained by the oxidation treatment is left as it is, it is easy to be eroded by the etching solution of the component and other acid solutions. Because the solution erosion at the interface is remarkable, the chemical resistance of the formed circuit is reduced. Therefore, it is preferable to carry out a reduction treatment to obtain a copper composite compound in which a part of copper oxide of “fine irregularities made of a copper compound” is converted into cuprous oxide. In this reduction treatment, by adjusting the reducing agent concentration, solution pH, solution temperature, and the like, the occupied area ratio of the Cu (I) peak of “fine irregularities made of a copper composite oxide” can be adjusted as appropriate. Note that the copper composite compound containing copper oxide and cuprous oxide may contain a small amount of metallic copper.

As can be understood from what has been described above, the surface-treated copper foil according to the present application is immersed in an oxidation treatment solution and contains copper oxide on the surface of the copper foil by a wet method. And then a reduction treatment is performed to form “fine irregularities made of a copper composite oxide” in which the occupied area ratio of the Cu (I) peak is 50% or more. Therefore, it is possible to simultaneously roughen both surfaces of the copper foil. Therefore, when this wet method is used, it is possible to easily obtain a double-side roughened copper foil suitable for forming the inner layer circuit of the multilayer printed wiring board.

Form of copper-clad laminate: The copper-clad laminate according to the present application is obtained using a surface-treated copper foil provided with the above-mentioned roughened layer. If the copper clad laminate at this time is obtained using the surface-treated copper foil according to the present application, there are no particular limitations on the constituent components, thickness, bonding method, etc. of the used insulating resin substrate. No. In addition, the concept of the copper-clad laminate referred to here includes the concept of both rigid type and flexible type.

As the electrolytic copper foil, an electrolytic copper foil (thickness: 18 μm) manufactured by Mitsui Metal Mining Co., Ltd. having a surface roughness (Rzjis) of 0.2 μm and a glossiness [Gs (60 °)] of 600 is used. The surface treatment was performed according to the following procedure.

Pretreatment: The electrolytic copper foil was immersed in an aqueous sodium hydroxide solution, subjected to alkali degreasing treatment, and washed with water. Then, the electrolytic copper foil after the alkaline degreasing treatment was immersed in a sulfuric acid solution having a hydrogen peroxide concentration of 1 mass% and a sulfuric acid concentration of 5 mass% for 5 minutes, and then washed with water.

Oxidation treatment: The electrolytic copper foil that has been subjected to the preliminary treatment is subjected to a liquid temperature of 70 ° C., pH = 12, a concentration of chlorous acid of 150 g / L, and a concentration of N-2- (aminoethyl) -3-aminopropyltrimethoxysilane. A predetermined oxidation treatment time (1 minute, 2 minutes, 4 minutes, 10 minutes) was immersed in a sodium hydroxide solution containing 10 g / L to form “fine irregularities made of a copper compound” on the surface of the electrolytic copper foil. Four types of samples were obtained.

Reduction treatment: Four types of samples after oxidation treatment were immersed in an aqueous solution (room temperature) with a dimethylamine borane concentration of 20 g / L adjusted to pH = 12 using sodium carbonate and sodium hydroxide for 1 minute to reduce. The surface treatment copper foil provided with the roughening process layer formed with "the fine unevenness | corrugation which consists of a copper complex compound" was processed, washed with water, and dried.

A scanning electron microscope observation image of the surface of the roughened layer of the surface-treated copper foil obtained in Example 1 is shown in FIG. When the surface of the roughened layer was subjected to state analysis using XPS, the presence of “Cu (I)”, “Cu (II)”, and “—COO group” was confirmed. Furthermore, the occupied area ratio, specific surface area, lightness L ^* and peel strength of the Cu (I) peak of the surface-treated copper foil obtained in this example are summarized in Table 1 below.

And, the peel strength in the present application was measured as follows. Using a surface-treated copper foil as a sample and a prepreg (R1551) manufactured by Panasonic Corporation, using a vacuum press machine, the press pressure is 2.9 MPa, the temperature is 190 ° C., and the press time is 90 minutes. A copper clad laminate was produced by bonding. Next, using this copper-clad laminate, a 3 mm width peel strength measurement linear circuit was manufactured by an etching method, and the peel strength was measured with this 3 mm circuit. In the specification, “kgf / cm” is used as a unit of peel strength, but it can be easily converted into “N / m” unit from the relationship of 1 kgf / cm = 980 N / m.

Using the same electrolytic copper foil as used in Example 1, surface treatment was performed according to the following procedure. The preliminary treatment and the oxidation treatment (oxidation treatment time: 2 minutes) are the same as those in Example 1. In Example 2, the following reduction treatment is adopted in order to examine the influence of the pH of the aqueous solution used for the reduction treatment and the dimethylamine borane concentration.

Reduction treatment: The electrolytic copper foil after the oxidation treatment is adjusted to three levels of pH = 11, 12, and 13 using sodium carbonate and sodium hydroxide, and the dimethylamine borane concentrations are 5 g / L, 10 g / L, and 20 g / L. The surface-treated copper foil according to the present application was obtained by dipping for 1 minute in each of nine types of aqueous solutions (room temperature) combining these three levels, performing a reduction treatment, washing with water, and drying. The surface-treated copper foils obtained when the aqueous solution used for the reduction treatment has pH = 11 are referred to as “implementation sample 11-a, implementation sample 11-b, and implementation sample 11-c”. The surface-treated copper foils obtained when the aqueous solution used for the reduction treatment has a pH of 12 are referred to as “implemented sample 12-a, implemented sample 12-b, and implemented sample 12-c”. The surface-treated copper foils obtained when the aqueous solution used for the reduction treatment has pH = 13 are referred to as “implemented sample 13-a, implemented sample 13-b, and implemented sample 13-c”. In addition, the “−a” display when indicating each of the samples is when the dimethylamine borane concentration in the aqueous solution used for the reduction treatment is 5 g / L. Then, “−b” is displayed when the dimethylamine borane concentration in the aqueous solution used for the reduction treatment is 10 g / L. “−c” is indicated when the dimethylamine borane concentration in the aqueous solution used for the reduction treatment is 20 g / L.

Scanning electron microscope observation images of the surface-treated copper foils of all the working samples obtained in Example 2 were in the same form as shown in FIG. Then, when the state of the “fine irregularities made of a copper composite compound” on the surface of the roughened layer of each of the working samples was analyzed using XPS, “Cu (I)”, “Cu (II)” and “− The presence of “COO group” was confirmed. The occupied area ratio, specific surface area, lightness L ^* and peel strength of the Cu (I) peak of the surface-treated copper foil obtained in this example are summarized in Table 2 below.

Comparative example

In the comparative example, using the same electrolytic copper foil as in the example, the same pretreatment as in the example was performed, the blackening process was performed, and the reduction process was further performed to obtain a comparative sample. Hereinafter, the blackening process and the reduction process will be described.

Blackening treatment: 10% by volume of “PRO BOND 80A OXIDE SOLUTION”, which is an oxidation treatment solution manufactured by Rohm & Haas Electronic Materials Co., Ltd., and “PRO BOND 80B OXIDE SOLUTION”, which has been subjected to the preliminary treatment. A general blackening treatment was formed on the surface by immersing in an aqueous solution containing 20 vol% and having a liquid temperature of 85 ° C. for 5 minutes.

Reduction treatment: The oxidized copper foil after the oxidation treatment is reduced to 6.7 vol% for “CIRCUPOSIT PB OXIDE CONVERTER 60C”, which is a reduction treatment solution manufactured by Rohm & Haas Electronic Materials Co., Ltd., and 1.5 vol for “CUPOSIT Z”. The sample was immersed in an aqueous solution containing 35% of a liquid temperature of 35 ° C. for 5 minutes, washed with water, and dried to obtain a comparative sample having a reduced blackening treatment surface shown in FIG.

When the state of the surface of the roughened layer of the surface-treated copper foil (comparative sample) obtained in this comparative example was analyzed using XPS, the presence of “Cu (0)” was clearly confirmed, and “Cu (II)” "And" Cu (I) "were also confirmed, but" -COO group "could not be confirmed. Table 2 shows the occupied area ratio, specific surface area, lightness L ^*, and peel strength of the Cu (I) peak of the surface-treated copper foil obtained in this comparative example.

[Contrast between Example and Comparative Example]
Comparison between Example 1 and Comparative Example: With reference to Table 1 below, Example 1 and Comparative Example are compared.

As can be understood from Table 1, even when the oxidation treatment time varies between 1 minute and 10 minutes, the maximum length of the “fine irregularities made of a copper composite compound” seen from the surface of the roughening treatment layer is 100 nm. Thus, there is no change in the contents detected in the analysis of the state of the roughened surface. On the other hand, the maximum length of the unevenness in the comparative example is 500 nm, which is about 5 times as large. That is, it can be seen that the “fine irregularities made of a copper composite compound” of the surface-treated copper foil according to the present application is extremely fine compared to the conventional blackening treatment.

Next, in terms of the specific surface area, the comparative example shows a larger value than the first embodiment. However, when these surface-treated copper foils are bonded to an insulating resin substrate and the peel strength is measured, the peel strength of the example is 0.63 kgf / cm to 0.78 kgf / cm. Even in the shortest oxidation treatment time, a practically sufficient peel strength is obtained, and a peel strength proportional to the value of the specific surface area is obtained. On the other hand, the peel strength of the comparative example having a higher specific surface area than that of Example 1 is as low as 0.33 kgf / cm. Usually, the higher the specific surface area value, the higher the peel strength, but vice versa. This is considered because the unevenness of the blackening treatment in the comparative example is deteriorated in strength. This will be described in detail in “Comparison between Example 2 and Comparative Example” described later. Moreover, when only Example 1 is seen, the specific surface area becomes large in proportion to the increase in oxidation treatment time. That is, it can be determined that the oxidation treatment time employed in Example 1 is appropriate. Further, the value of the lightness L ^* of the roughened surface of Example 1 is 18 to 20, which is a very small value.

Furthermore, in FIG. 2, the scanning electron microscope observation for seeing the roughening form of the electrode surface side and precipitation surface side of the surface treatment copper foil obtained on the conditions for the immersion time of 2 minutes of the oxidation treatment in Example 1 The image is shown. From FIG. 2, on a macro basis, the surface shapes on the electrode surface side and the deposition surface side of the electrolytic copper foil before roughening are maintained after roughening, and along the surface shape before roughening, “copper composite compound” It can be seen that "fine irregularities made of" are formed. Therefore, in the case of the surface-treated copper foil according to the present application, while maintaining the macroscopic surface shape of the copper foil before being roughened by the “fine irregularities made of a copper composite compound”, the roughness in a shape along the surface shape is maintained. It is clear that this is being done.

Comparison between Example 2 and Comparative Example: With reference to Table 2 below, Example 2 and Comparative Example are compared.

In Table 2, paying attention to the occupied area ratio of the Cu (I) peak, the surface-treated copper foils obtained when the aqueous solution used for the reduction treatment is pH = 11 (Example 11-a, Example 11-b, Example) Sample 11-c), surface-treated copper foils obtained when the aqueous solution used for the reduction treatment had a pH = 12 (Example Sample 12-a, Example Sample 12-b, Example Sample 12-c), and reduction treatment Looking at the surface-treated copper foils (Example 13-a, Example 13-b, Example 13-c) obtained when the aqueous solution used had a pH = 13, the occupied area ratio of the Cu (I) peak was The range is 59% to 99%. On the other hand, even in the comparative sample, the occupied area ratio of the Cu (I) peak is 83%. Therefore, it can be seen that there is no difference between the example and the comparative example in the occupied area ratio of the Cu (I) peak, but the detected components are different in the state analysis by XPS described above.

Therefore, the roughened state of the implementation sample and the comparative sample will be compared with an electron microscope observation image. When FIG. 2 is seen, the roughening state which concerns on an implementation sample can be understood. And when FIG. 3 is seen, the state of the cross section of the roughening process layer which concerns on an implementation sample can be understood. In contrast, in the comparative example, the roughened electron microscope observation image shown in FIG. 4A immediately after the blackening treatment shows a long and thick needle shape, and the tip of the blackening treatment is sharply pointed. ing. The thickness of the roughened layer formed by this needle shape was 500 nm to 700 nm. However, when the reduction process is performed and the reduction blackening process is performed, as shown in FIG. 4B, it can be understood that the top of the irregularities is rounded, and the roughened shape is greatly changed by the reduction process.

Further, FIG. 5A shows a cross section of the roughened layer immediately after blackening in the comparative example. FIG. 5B shows a cross section after the reduction process and the reduction blackening process. It can be seen from FIG. 5 that the uneven shape before the reduction is considerably damaged by the reduction treatment. That is, it can be seen that the needle-like shape formed by the oxidation treatment is thinned and finely broken by the reduction treatment. On the other hand, the roughened shape of the “fine irregularities made of a copper composite compound” in the example is not damaged at all even when the reduction treatment is performed, as can be understood from the cross section of FIG. Therefore, it can be predicted that the unevenness after the reduction treatment of the comparative sample is very fragile as compared with the working sample, and the so-called problem of powder falling occurs.

Therefore, the peel strength of the surface-treated copper foil obtained in Example 2 and the comparative example will be compared. As a result, the peel strength of the working sample is 0.70 kgf / cm to 0.81 kgf / cm. On the other hand, the peel strength of the comparative sample is 0.33 kgf / cm, which is lower than that of the working sample.

The surface-treated copper foil according to the present application described above is roughened with "fine irregularities made of a copper composite compound having a maximum length of 500 nm or less", and the insulating resin base material of the non-roughened copper foil Compared with the adhesiveness with respect to, good adhesiveness with the insulating resin substrate can be ensured. Moreover, the surface-treated copper foil according to the present application “because the fine irregularities made of the copper composite compound having a maximum length of 500 nm or less are very fine”, and therefore, an extremely short over-etching time is required for the etching process. Therefore, it is expected that a fine pitch circuit having a good etching factor can be formed. Therefore, it can be usefully used in all printed wiring board products. In addition, as described above, the surface-treated copper foil according to the present application can be made into a form in which the both surfaces of the copper foil are roughened, and the double-sided roughening suitable for forming the inner layer circuit of the multilayer printed wiring board. Can be treated copper foil.

Claims

In the surface-treated copper foil that roughened the surface of the copper foil,
A surface-treated copper foil comprising a roughened layer formed of needle-like or plate-like fine irregularities made of a copper composite compound having a maximum length of 500 nm or less on the surface of the copper foil.
The needle-like or plate-like fine irregularities made of the copper composite compound have a maximum length when observed from the surface of the roughened layer at a tilt angle of 45 ° and a magnification of 50000 times or more using a scanning electron microscope. The surface-treated copper foil according to claim 1, wherein the thickness is 150 nm or less.
The needle-like or plate-like fine irregularities made of the copper composite compound have a Cu (I) peak when the total area of each peak area of Cu (I) and Cu (II) when analyzed by XPS is 100%. The surface-treated copper foil according to claim 1 or 2, wherein the occupied area ratio is 50% or more.
The surface-treated copper foil according to any one of claims 1 to 3, wherein the needle-like or plate-like fine irregularities made of the copper composite compound contain copper oxide and cuprous oxide.
5. The surface treatment according to claim 1, wherein the needle-like or plate-like fine irregularities made of the copper composite compound have a specific surface area measured by adsorbing krypton of 0.035 m 2 / g or more. Copper foil.
The surface-treated copper foil according to any one of claims 1 to 5, wherein the surface of the roughened layer has a lightness L * of the L * a * b * color system of 25 or less.
A copper-clad laminate obtained by using the surface-treated copper foil according to any one of claims 1 to 6.