JPWO2017018232A1 - Roughening copper foil, copper clad laminate and printed wiring board - Google Patents

Abstract

Although it is a low roughness fine irregularity suitable for fine pitch circuit formation and high frequency applications, it is excellent not only in adhesion to the resin but also in abrasion resistance. Therefore, processing of copper-clad laminate or printed wiring board Provided is a roughened copper foil capable of stably exhibiting excellent adhesion with a resin even after being rubbed against something in production. The roughened copper foil of this invention has the roughened surface provided with the fine unevenness | corrugation comprised with a needle-like crystal and / or a plate-like crystal on at least one side. The roughened surface has a maximum height Sz measured in accordance with ISO25178 of 1.5 μm or less, and an arithmetic average music Spc at the peak measured in accordance with ISO25178 is 1300 mm−1 or less. .

Description

  The present invention relates to a roughened copper foil, a copper clad laminate, and a printed wiring board.

  As a printed wiring board copper foil suitable for the formation of fine pitch circuits, roughening with fine irregularities formed as a roughening treatment surface through oxidation treatment and reduction treatment (hereinafter sometimes referred to as redox treatment). Treated copper foil has been proposed.

  For example, Patent Document 1 (International Publication No. 2014/126193) discloses a surface provided with a roughening treatment 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. A treated copper foil is disclosed. Further, Patent Document 2 (International Publication No. 2015/040998) discloses roughening having fine irregularities formed from needle-like or plate-like convex portions having a maximum length of 500 nm or less made of a copper composite compound. A copper foil provided with at least one surface of a treatment layer and a silane coupling agent treatment layer on the surface of the roughening treatment layer is disclosed. According to the roughened copper foils of these documents, it is possible to obtain good adhesion with the insulating resin base material due to the anchor effect due to the fine unevenness of the roughened layer and to have a good etching factor. It is said that a fine pitch circuit can be formed. Each of the roughening treatment layers having fine irregularities disclosed in Patent Documents 1 and 2 is formed through a redox treatment after a preliminary treatment such as alkaline degreasing. The fine irregularities thus formed have a specific shape composed of needle-like crystals and / or plate-like crystals of a copper composite compound, and the roughened surface provided with such fine irregularities is attached with fine copper particles. The roughened surface is generally finer than the roughened surface formed by etching or the roughened surface provided with irregularities by etching.

  On the other hand, with the advancement of functions of portable electronic devices and the like in recent years, the frequency of signals has been increased to perform high-speed processing of a large amount of information, and a printed wiring board suitable for high-frequency applications is required. Such a high-frequency printed wiring board is desired to reduce transmission loss in order to enable transmission of high-frequency signals without degrading quality. A printed wiring board is provided with a copper foil processed into a wiring pattern and an insulating resin base material, but the transmission loss is a conductor loss due to the copper foil and a dielectric loss due to the insulating resin base material. It consists mainly of Also, the conductor loss can be further increased by the skin effect of the copper foil that appears more prominently at higher frequencies. For this reason, in order to reduce transmission loss in high frequency applications, low-roughness copper foil is required as a copper foil that can reduce conductor loss. In this regard, Patent Document 2 describes that the copper foil provided with the above-described roughening treatment layer is suitable as a high-frequency circuit forming material.

International Publication No. 2014/126193 International Publication No. 2015/040998

  However, the fine irregularities formed through the oxidation-reduction treatment are deteriorated in shape by rubbing between copper foils (which may occur when the copper foil is pulled out from the roll state) or rubbing with other members (for example, a transport roller). It's easy to do. This is because the fine irregularities as described above are composed of needle-like crystals and / or plate-like crystals of a copper composite compound, so that the needle-like crystals and / or the plate-like crystals may break or fall down in some cases. Because there is. The fine irregularities whose shape is deteriorated by rubbing in this way not only impairs the appearance of the roughened copper foil, but also reduces the anchor effect on the insulating resin substrate due to the fine irregularities. For this reason, there is a concern that the yield may be reduced due to poor appearance or deterioration of performance (particularly a decrease in adhesion to the resin).

The present inventors have recently controlled the shape of fine irregularities formed through oxidation-reduction treatment, and the maximum height Sz measured in conformity with ISO25178 is 1.5 μm or less, and conforms to ISO25178. The arithmetic average music Spc at the peak of the peak measured in this way is 1300 mm ⁻¹ or less, so that it is in close contact with the resin even though it has fine roughness and low roughness suitable for fine pitch circuit formation and high frequency applications. Excellent resistance to rubbing as well as high resistance, and therefore stable adhesion to the resin even after rubbing against something in the processing of copper-clad laminates or printed wiring boards I got the knowledge that I can do it.

  Therefore, the object of the present invention is not only the fine roughness of the low roughness suitable for fine pitch circuit formation and high frequency applications, but also excellent in not only the adhesion to the resin but also the abrasion resistance, and therefore, the copper-clad laminate An object of the present invention is to provide a roughened copper foil capable of stably exhibiting excellent adhesion to a resin even after being rubbed against something in the processing of a board or the production of a printed wiring board.

According to one aspect of the present invention, there is provided a roughened copper foil having a roughened surface on at least one side provided with fine irregularities composed of needle-like crystals and / or plate-like crystals, The processed surface has a maximum height Sz measured in accordance with ISO 25178 of 1.5 μm or less, and an arithmetic average music Spc at the peak of the mountain measured in accordance with ISO 25178 is 1300 mm ⁻¹ or less. A treated copper foil is provided.

  According to the other one aspect | mode of this invention, the copper clad laminated board provided with the roughening process copper foil of the said aspect is provided.

  According to the other one aspect | mode of this invention, the printed wiring board provided with the roughening process copper foil of the said aspect is provided.

Definitions The definitions of terms and parameters used to specify the present invention are shown below.

In this specification, the “maximum height Sz” is a parameter representing the distance from the highest point to the lowest point on the surface, measured in accordance with ISO25178. The maximum height Sz can be calculated by measuring a surface profile of a predetermined measurement area (for example, a two-dimensional region of 22,500 μm ² ) on the roughened surface with a commercially available laser microscope.

In this specification, the “arithmetic mean music Spc at the peak” is a parameter representing the arithmetic average of the principal curvatures at the peak in the definition area, which is measured in accordance with ISO25178. A small value indicates that the point in contact with another object is rounded. On the other hand, a large value indicates that a point in contact with another object is sharp. In short, the arithmetic mean song Spc at the top of the mountain can be said to be a parameter representing the roundness of the hump that can be measured with a laser microscope. The arithmetic mean music Spc at the top of the mountain can be calculated by measuring the surface profile of a predetermined measurement area (for example, a two-dimensional region of 100 μm ² ) on the roughened surface with a commercially available laser microscope.

  In this specification, the “electrode surface” of the electrolytic copper foil refers to the surface on the side that was in contact with the cathode during the production of the electrolytic copper foil.

  In the present specification, the “deposition surface” of the electrolytic copper foil refers to the surface on the side where the electrolytic copper is deposited during the production of the electrolytic copper foil, that is, the surface not in contact with the cathode.

Roughened copper foil The copper foil of the present invention is a roughened copper foil. This roughened copper foil has a roughened surface on at least one side. The roughened surface is provided with fine irregularities composed of needle-like crystals and / or plate-like crystals, and such fine irregularities can be formed through oxidation-reduction treatment. The crystal and / or plate-like crystal is observed in a shape (for example, a lawn shape) that grows substantially perpendicularly and / or obliquely to the copper foil surface. The roughened surface has a maximum height Sz measured in accordance with ISO25178 of 1.5 μm or less, and an arithmetic average music Spc at the peak measured in accordance with ISO25178 is 1300 mm ^−1. It is as follows. In this way, the shape of the fine irregularities formed through the oxidation-reduction treatment is controlled so that the maximum height Sz is 1.5 μm or less and the arithmetic mean music Spc at the peak is 1300 mm ⁻¹ or less. This makes it possible to form fine pitch circuits and low roughness fine irregularities suitable for high frequency applications, but also has excellent resistance to abrasion as well as adhesion to the resin. In addition, even after rubbing against something in the production of a printed wiring board, it is possible to stably exhibit excellent adhesion with a resin. In particular, as defined above, the arithmetic mean song Spc at the peak of the mountain is a parameter representing the roundness of the hump, and the smaller the value, the rounder the point that comes into contact with another object. Therefore, it is considered that the above excellent rub resistance is because it becomes difficult for needle-like crystals and / or plate-like crystals to be broken or fall down by reducing this Spc to 1300 mm ⁻¹ or less. That is, as described above, the fine irregularities formed through the conventional oxidation-reduction treatment are likely to deteriorate in shape due to rubbing between copper foils and rubbing with other members, resulting in poor appearance and performance (particularly adhesion to the resin). However, according to the roughened copper foil of the present invention, such a technical problem can be solved.

  The maximum height Sz on the roughened surface is 1.5 μm or less, preferably 1.2 μm or less, more preferably 1.0 μm or less. Sz within such a range is more suitable for fine pitch circuit formation and high frequency applications. In particular, such low roughness reduces the skin effect of copper foil, which is a problem in high-frequency signal transmission, and reduces conductor loss due to copper foil, thereby significantly reducing high-frequency signal transmission loss. can do. The lower limit of Sz is not particularly limited, but Sz is preferably 0.1 μm or more, more preferably 0.2 μm or more, and still more preferably 0.3 μm or more, from the viewpoint of improving adhesion with the resin.

The arithmetic mean music Spc of the peak on the roughened surface is 1300 mm ⁻¹ or less, preferably 1200 mm ⁻¹ or less, more preferably 1000 mm ⁻¹ or less. If it is Spc within these ranges, it is possible to form a rounded bump shape that is more difficult to rub, and thus the rub resistance can be improved. The lower limit of Spc is not particularly limited, but is preferably 100 mm ⁻¹ or more, more preferably 200 mm ⁻¹ or more, and further preferably 300 mm ⁻¹ or more.

  As described above, the fine irregularities on the roughened surface are constituted by needle crystals and / or plate crystals. The height of the acicular crystal and / or plate crystal (that is, the height measured in the vertical direction from the root of the acicular crystal and / or plate crystal) is preferably 50 to 400 nm, more preferably 100. It is -400 nm, More preferably, it is 150-350 nm.

  Although the thickness of the roughening copper foil of this invention is not specifically limited, 0.1-35 micrometers is preferable, More preferably, it is 0.5-18 micrometers. In addition, the roughening copper foil of this invention is not restricted to what roughened the surface of normal copper foil, Even if it roughened the copper foil surface of copper foil with a carrier. Good.

Production Method The roughened copper foil according to the present invention may be produced by any method, but is preferably produced through an oxidation-reduction treatment. Hereinafter, an example of the preferable manufacturing method of the roughening copper foil by this invention is demonstrated. This preferred manufacturing method includes a step of preparing a copper foil having a surface having a maximum height Sz of 1.5 μm or less, and a roughening step (oxidation-reduction treatment) in which preliminary treatment, oxidation treatment, and reduction treatment are sequentially performed on the surface. ).

(1) Preparation of copper foil As copper foil used for manufacture of a roughening process copper foil, use of both electrolytic copper foil and rolled copper foil is possible, More preferably, it is electrolytic copper foil. Further, the copper foil may be a non-roughened copper foil or a pre-roughened copper foil. Although the thickness of copper foil is not specifically limited, 0.1-35 micrometers is preferable, More preferably, it is 0.5-18 micrometers. When the copper foil is prepared in the form of a copper foil with a carrier, the copper foil is prepared by a wet film formation method such as an electroless copper plating method and an electrolytic copper plating method, a dry film formation method such as sputtering and chemical vapor deposition, or It may be formed by a combination thereof.

  The surface of the copper foil to be roughened preferably has a maximum height Sz measured in accordance with ISO25178 of 1.5 μm or less, more preferably 1.2 μm or less, and even more preferably 1 0.0 μm or less. Within the above range, the surface profile required for the roughened copper foil of the present invention, in particular, the maximum height Sz of 1.5 μm or less can be easily realized on the roughened surface. The lower limit value of Sz is not particularly limited, but Sz is preferably 0.1 μm or more, more preferably 0.2 μm or more, and further preferably 0.3 μm or more.

(2) Roughening treatment (redox treatment)
Thus, it is preferable to subject the surface of the copper foil provided with the low Sz to a wet roughening step in which preliminary treatment, oxidation treatment, and reduction treatment are sequentially performed. In particular, a copper compound containing copper oxide (cupric oxide) is formed on the surface of the copper foil by oxidizing the surface of the copper foil by a wet method using a solution. Thereafter, the copper compound is reduced to convert a part of the copper oxide into cuprous oxide (cuprous oxide), thereby forming needle-like crystals composed of a copper composite compound containing copper oxide and cuprous oxide and / Or the fine unevenness | corrugation comprised with a plate-shaped crystal | crystallization can be formed in the surface of copper foil. Here, the fine irregularities are formed of a copper compound containing copper oxide as a main component at the stage where the surface of the copper foil is oxidized by a wet method. When the copper compound is reduced, a part of the copper oxide is converted into cuprous oxide while maintaining the shape of the fine irregularities formed by the copper compound, and the copper oxide and the cuprous oxide are reduced. It becomes the fine unevenness | corrugation which consists of a copper complex compound to contain. Thus, after performing the appropriate oxidation process by the wet method on the surface of copper foil, the reduction | restoration process is performed, and it becomes possible to form the fine unevenness | corrugation of nm order.

(2a) Pretreatment Prior to the oxidation treatment, the copper foil is preferably subjected to a pretreatment such as degreasing. In this preliminary treatment, it is preferable that the copper foil is immersed in an aqueous sodium hydroxide solution to perform an alkaline degreasing treatment and then washed with water. A preferable aqueous sodium hydroxide solution has a NaOH concentration of 20 to 60 g / L, a liquid temperature of 30 to 60 ° C., and a preferable immersion time is 2 seconds to 5 minutes. Moreover, after immersing the copper foil in which the alkali degreasing process was performed in sulfuric acid type aqueous solution, it is preferable to wash with water. A preferable sulfuric acid aqueous solution has a sulfuric acid concentration of 1 to 20% by mass and a liquid temperature of 20 to 50 ° C., and a preferable immersion time is 2 seconds to 5 minutes.

(2b) Oxidation treatment The copper foil subjected to the above pretreatment is subjected to an oxidation treatment using an alkaline solution such as a sodium hydroxide solution. By oxidizing the surface of the copper foil with an alkaline solution, fine irregularities composed of needle-like crystals and / or plate-like crystals made of a copper composite compound mainly composed of copper oxide can be formed on the surface of the copper foil. it can. At this time, the temperature of the alkaline solution is preferably 60 to 85 ° C., and the pH of the alkaline solution is preferably 10 to 14. Moreover, it is preferable that an alkaline solution contains a chlorate, a chlorite, a hypochlorite, and a perchlorate from a viewpoint of oxidation, and the density | concentration has preferable 100-500 g / L. The oxidation treatment is preferably performed by immersing the electrolytic copper foil in an alkaline solution, and the immersion time (that is, the oxidation time) is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes.

  The alkaline solution used for the oxidation treatment preferably further contains an oxidation inhibitor. That is, when the surface of the copper foil is oxidized with an alkaline solution, the convex portion may grow excessively and exceed the desired length, making it difficult to form the desired fine irregularities. Become. Therefore, in order to form the fine irregularities, it is preferable to use an alkaline solution containing an oxidation inhibitor capable of suppressing oxidation on the copper foil surface. An example of a preferred oxidation inhibitor is an amino silane coupling agent. By subjecting the copper foil surface to an oxidation treatment using an alkaline solution containing an amino silane coupling agent, the amino silane coupling agent in the alkaline solution is adsorbed on the surface of the copper foil, and the copper foil surface by the alkaline solution Can be suppressed. As a result, it is possible to suppress the growth of copper oxide needle-like crystals and / or plate-like crystals, and to form a desirable roughened surface with extremely fine irregularities. Specific examples of the amino silane coupling agent include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and 3-aminopropyl. Trimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane and the like are particularly preferable. Is N-2- (aminoethyl) -3-aminopropyltrimethoxysilane. All of these are dissolved in an alkaline solution, stably held in the alkaline solution, and exhibit the effect of suppressing oxidation of the copper foil surface described above. The preferable concentration of the amino-based silane coupling agent (for example, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane) in the alkaline solution is 0.01 to 20 g / L, more preferably 0.02 to 20 g. / L.

(2c) Reduction treatment The copper foil that has been subjected to the oxidation treatment (hereinafter referred to as the oxidation-treated copper foil) is subjected to a reduction treatment using a reduction treatment solution. By converting a part of copper oxide into cuprous oxide (cuprous oxide) by reduction treatment, it is composed of needle-like crystals and / or plate-like crystals made of a copper composite compound containing copper oxide and cuprous oxide. Can be formed on the surface of the copper foil. This reduction treatment may be performed by bringing the reduction treatment liquid into contact with the oxidation treatment copper foil. At this time, the amount of dissolved oxygen in the reduction treatment liquid is increased by the arithmetic average song Spc at the peak of 1300 mm ⁻¹ or less. It is preferable in forming the roughened surface. It is considered that by increasing the amount of dissolved oxygen, it is possible to balance the oxidation effect of dissolved oxygen and the reducing power of the reducing agent, thereby realizing the above-mentioned Spc. Examples of a technique for increasing the amount of dissolved oxygen in the reduction treatment liquid include a technique for immersing the oxidation-treated copper foil while stirring the reduction treatment liquid, and a technique for applying the reduction treatment liquid to the oxidation-treated copper foil with a shower. Particularly preferably, it is a method of applying the reduction treatment liquid in a shower because it can easily achieve a desirable Spc. In this case, the time for applying the reduction treatment liquid in the shower may be as short as about 2 to 60 seconds, More preferably, it is 5 to 30 seconds. A preferred reduction treatment solution is a dimethylamine borane aqueous solution, and this aqueous solution preferably contains dimethylamine borane at a concentration of 10 to 40 g / L. The aqueous dimethylamine borane solution is preferably adjusted to pH 12 to 14 using sodium carbonate and sodium hydroxide. The temperature of the aqueous solution at this time is not particularly limited, and may be room temperature. The copper foil thus subjected to the reduction treatment is preferably washed with water and dried.

(3) Rust prevention treatment If desired, the copper foil after the roughening treatment may be subjected to a rust prevention treatment to form a rust prevention layer. Examples of the rust preventive layer include an inorganic rust preventive layer using an inorganic component, an organic rust preventive layer using an organic component, and combinations thereof. A preferable inorganic rust preventive layer contains one or more elements such as zinc, tin, nickel, cobalt, molybdenum, tungsten, titanium, and chromium. Preferred organic anticorrosive layers are those containing a triazole compound, more preferably benzotriazole, carboxybenzotriazole, methylbenzotriazole, aminotriazole, nitrobenzotriazole, hydroxybenzotriazole, chlorobenzotriazole, ethylbenzotriazole, naphthotriazole. Or any combination thereof.

(4) Silane coupling agent treatment If desired, the copper foil after the roughening treatment may be treated with a silane coupling agent to form a silane coupling agent layer. Thereby, moisture resistance, chemical resistance, adhesiveness with an adhesive agent, etc. can be improved. The silane coupling agent layer can be formed by appropriately diluting and applying a silane coupling agent and drying. Examples of silane coupling agents include epoxy-functional silane coupling agents such as 4-glycidylbutyltrimethoxysilane and 3-glycidoxypropyltrimethoxysilane, or 3-aminopropyltriethoxysilane, N-2 (amino Amino functions such as ethyl) 3-aminopropyltrimethoxysilane, N-3- (4- (3-aminopropoxy) butoxy) propyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane Silane coupling agent, or mercapto functional silane coupling agent such as 3-mercaptopropyltrimethoxysilane, or olefin functional silane coupling agent such as vinyltrimethoxysilane, vinylphenyltrimethoxysilane, or 3-methacryloxypropyl Trime Acrylic-functional silane coupling agent such as Kishishiran, or imidazole functional silane coupling agent such as imidazole silane, or triazine functional silane coupling agents such as triazine silane.

  In addition, you may perform both a rust prevention process as mentioned above and a silane coupling agent process as mentioned above.

Copper- clad laminate The roughened copper foil of the present invention is preferably used for the production of a copper-clad laminate for printed wiring boards. That is, according to the preferable aspect of this invention, the copper clad laminated board provided with the said roughened copper foil or the copper clad laminated board obtained using the said roughened copper foil is provided. This copper-clad laminate includes the roughened copper foil of the present invention and a resin layer provided in close contact with the roughened surface of the roughened copper foil. The roughened copper foil may be provided on one side of the resin layer or on both sides. The resin layer comprises a resin, preferably an insulating resin. The resin layer is preferably a prepreg and / or a resin sheet. The prepreg is a general term for composite materials in which a base material such as a synthetic resin plate, a glass plate, a glass woven fabric, a glass nonwoven fabric, and paper is impregnated with a synthetic resin. Preferable examples of the insulating resin include an epoxy resin, a cyanate resin, a bismaleimide triazine resin (BT resin), a polyphenylene ether resin, and a phenol resin. Examples of the insulating resin that constitutes the resin sheet include insulating resins such as epoxy resins, polyimide resins, and polyester resins. Moreover, the filler particle etc. which consist of various inorganic particles, such as a silica and an alumina, may contain in the resin layer from a viewpoint of improving insulation. Although the thickness of a resin layer is not specifically limited, 1-1000 micrometers is preferable, More preferably, it is 2-400 micrometers, More preferably, it is 3-200 micrometers. The resin layer may be composed of a plurality of layers. A resin layer such as a prepreg and / or a resin sheet may be provided on the roughened copper foil via a primer resin layer applied to the surface of the copper foil in advance.

Printed wiring board The roughened copper foil of the present invention is preferably used for the production of a printed wiring board. That is, according to the preferable aspect of this invention, the printed wiring board provided with the said roughening process copper foil or the printed wiring board obtained using the said roughening process copper foil is provided. The printed wiring board according to this aspect includes a layer configuration in which a resin layer and a copper layer are laminated in this order. The resin layer is as described above for the copper-clad laminate. In any case, a known layer structure can be adopted for the printed wiring board. As a specific example related to the printed wiring board, a single-sided or double-sided printed wiring board formed with a circuit on a laminated body obtained by bonding the roughened copper foil of the present invention to one side or both sides of the prepreg, and multilayered these. A multilayer printed wiring board etc. are mentioned. Other specific examples include a flexible printed wiring board, a COF, a TAB tape, and the like that form a circuit by forming the roughened copper foil of the present invention on a resin film. As another specific example, a copper foil with resin (RCC) in which the above-described resin layer is applied to the roughened copper foil of the present invention is formed, and the resin layer is laminated on the above-described printed circuit board as an insulating adhesive layer. After that, the build-up wiring board in which the circuit is formed by using the modified semi-additive (MSAP) method, the subtractive method, etc., with the roughened copper foil as a whole or a part of the wiring layer, and the roughened copper foil are removed. Examples thereof include a build-up wiring board in which a circuit is formed by a semi-additive (SAP) method, and a direct build-up on wafer in which the lamination of a copper foil with resin and circuit formation are alternately repeated on a semiconductor integrated circuit.

  The present invention is more specifically described by the following examples.

Examples 1-10
The roughened copper foil of the present invention was produced as follows.

(1) Production of electrolytic copper foil Using a copper sulfate acidic copper sulfate solution having the composition shown below as a copper electrolyte, using a rotating electrode made of titanium as a cathode, and using DSA (dimensional stability anode) as an anode, Electrolysis was performed at a solution temperature of 45 ° C. and a current density of 55 A / dm ² to obtain an electrolytic copper foil having a thickness of 12 μm. When the deposition surface of this electrolytic copper foil and the maximum height Sz of the electrode surface were measured by the method described later, the Sz of the deposition surface was 0.8 μm and the Sz of the electrode surface was 1.2 μm.
<Composition of sulfuric acid copper sulfate solution>
-Copper concentration: 80 g / L
-Sulfuric acid concentration: 260 g / L
-Bis (3-sulfopropyl) disulfide concentration: 30 mg / L
-Diallyldimethylammonium chloride polymer concentration: 50 mg / L
-Chlorine concentration: 40 mg / L

(2) Roughening treatment (redox treatment)
The electrode surface side (Examples 1 to 5) or the deposition surface side (Examples 6 to 10) of the obtained electrolytic copper foil is subjected to a roughening treatment (oxidation reduction treatment) in a three-stage process shown below. It was. That is, the following pretreatment, oxidation treatment, and reduction treatment were performed in this order.

<Preliminary processing>
The electrolytic copper foil obtained in the above (1) was immersed in an aqueous sodium hydroxide solution having a NaOH concentration of 50 g / L for 1 minute at a liquid temperature of 40 ° C., subjected to an alkaline degreasing treatment, and then washed with water. The electrolytic copper foil subjected to the alkaline degreasing treatment was immersed in a sulfuric acid aqueous solution having a sulfuric acid concentration of 5 mass% for 1 minute, and then washed with water.

<Oxidation treatment>
An oxidation treatment was performed on the electrolytic copper foil subjected to the preliminary treatment. In this oxidation treatment, the electrolytic copper foil has a liquid temperature of 70 ° C., a pH = 12, a chlorous acid concentration of 150 g / L, and an N-2- (aminoethyl) -3-aminopropyltrimethoxysilane concentration of 10 g / L. It was performed by immersing in a sodium hydroxide solution for the time shown in Table 1. In this way, the fine unevenness | corrugation comprised by the acicular crystal | crystallization and / or plate-like crystal which consist of a copper complex compound which has copper oxide as a main component was formed in both surfaces of the electrolytic copper foil.

<Reduction treatment>
A reduction treatment was performed on the sample subjected to the oxidation treatment. In this reduction treatment, the concentration of dimethylamine borane adjusted to pH = 12 using sodium carbonate and sodium hydroxide on the electrode surface side or the precipitation surface side of the electrolytic copper foil on which fine irregularities were formed by the oxidation treatment was 20 g / This was carried out by applying an aqueous solution of L in a shower for 10 seconds. The temperature of the aqueous solution at this time was room temperature. The sample thus reduced was washed with water and dried. Through these steps, a part of the copper oxide on one side of the electrolytic copper foil is reduced to cuprous oxide, and a roughened surface having fine irregularities made of a copper composite compound containing copper oxide and cuprous oxide, and did. In this way, a roughened copper foil having a roughened surface provided with fine irregularities composed of needle-like crystals and / or plate-like crystals on at least one side was obtained.

Example 11 (Comparison)
A roughened copper foil was prepared in the same manner as in Example 2 except that the aqueous solution in the reduction treatment was attached by immersing the oxidized sample in the aqueous solution instead of using a shower. went.

Examples 12 and 13 (Comparison)
Pretreatment was performed in the same manner as (2) in Example 1 on the deposition surface side (Example 12) or electrode surface side (Example 13) of the electrolytic copper foil obtained in the same manner as in Example 1 (1). Then, the roughening process copper foil was produced by performing the conventional oxidation process and reduction process (redox process) which are shown below.

<Oxidation treatment>
The electrolytic copper foil was oxidized. This oxidation treatment contains 10 vol% of “PRO BOND 80A OXIDE SOLUTION” and 20 vol% of “PRO BOND 80B OXIDE SOLUTION”, which is an oxidation treatment solution manufactured by Rohm & Haas Electronic Materials Co., Ltd. It was performed by immersing in an aqueous solution having a liquid temperature of 85 ° C. for 5 minutes.

<Reduction treatment>
Reduction treatment was performed on the electrolytic copper foil subjected to the oxidation treatment. In this reduction treatment, “CIRCUPOSIT PB OXIDE CONVERTER 60C”, which is a reduction treatment solution manufactured by Rohm & Haas Electronic Materials Co., Ltd., is 6.7 vol%, and “CUPOSITZ” is 1%. It was performed by applying an aqueous solution containing 5 vol% of a liquid temperature of 35 ° C. with a shower for 10 seconds. The sample thus reduced was washed with water and dried.

Examples 14 and 15 (Comparison)
Example 12 (in the case of Example 14) or Example 13 (in the case of Example 15) except that the reduction treatment was performed by immersing the oxidized sample in an aqueous solution for 5 minutes instead of using a shower. In the same manner as above, a roughened copper foil was prepared.

Various evaluation shown below was performed about the roughening process copper foil produced in Evaluation Examples 1-15.

<Maximum height Sz>
The maximum height Sz on the roughened surface of the roughened copper foil was measured according to ISO25178 by surface texture analysis using a laser microscope (manufactured by Keyence Corporation, VK-X100). Specifically, the surface profile of a two-dimensional area with an area of 22500 μm ^{2 on} the roughened surface of the roughened copper foil was measured by a laser method. The average value when measuring three places on the same sample was adopted as the value of the maximum height Sz. Measurement of the maximum height Sz of the deposited surface or electrode surface of the electrolytic copper foil before the roughening treatment in each of the examples described above was also performed in the same procedure as described above.

<The arithmetic mean song Spc at the top of the mountain>
The arithmetic average music Spc at the peak of the roughened surface of the roughened copper foil was measured according to ISO25178 by surface texture analysis using a laser microscope (manufactured by Keyence Corporation, VK-X100). Specifically, the surface profile of a two-dimensional region having an area of 100 μm ^{2 on} the roughened surface of the roughened copper foil was measured by a laser method. The average value when 10 places were measured for the same sample was adopted as the arithmetic average song Spc at the top of the mountain.

<Rubbing resistance-brightness difference ΔL before and after rubbing test>
In order to evaluate the rubbing resistance of the roughened copper foil, the change in lightness L ^* (in the L ^* a ^* b ^* color system) of the roughened copper foil before and after the rubbing test (ΔL) Was measured. The lightness L ^* was measured according to JIS Z8722: 2000 using a spectral color difference meter (SE2000, manufactured by Nippon Denshoku Industries Co., Ltd.). At this time, the white plate attached to the measuring apparatus was used for the brightness calibration. This measurement was performed three times for the same part, and the average value of the three measurements was adopted as the value of the lightness L ^* of the roughened copper foil. Next, as a rubbing test, a plurality of the prepared roughened copper foils were laminated, and one roughening treatment located inside the laminate while applying a load of 5 kgf / cm ² from the top of the obtained laminate. The copper foil was pulled out. The lightness L ^* of the roughened surface of the drawn roughened copper foil was measured in the same manner as described above. The difference (ΔL) in brightness L ^* before and after the rubbing test thus obtained was used as an evaluation index for rubbing resistance. Specifically, a lightness difference ΔL before and after the rubbing test was determined to be “good” and a lightness difference ΔL exceeding 10 was determined to be “poor”.

<Adhesion with resin-peeling strength after rubbing test>
As the insulating resin base material, two prepregs (manufactured by Panasonic Corporation, MEGRON4, thickness 100 μm) were prepared and stacked. On this stacked prepreg, the roughened copper foil (extracted from the laminate while applying a load) subjected to the above rubbing test is laminated so that the roughened surface comes into contact with the prepreg, and a vacuum press is used. Then, a copper-clad laminate was produced by pressing under conditions of a pressing pressure of 2.9 MPa, a temperature of 200 ° C., and a pressing time of 90 minutes. Next, a test substrate provided with a 3.0 mm width peeling strength measuring linear circuit was fabricated on this copper-clad laminate by an etching method. The linear circuit thus formed was peeled off from the insulating resin substrate according to JIS C6481-1996, and the peel strength (kgf / cm) was measured.

Results The evaluation results obtained in Examples 1 to 15 were as shown in Table 1. As shown in Table 1, the roughened copper foil produced in Examples 1 to 10 satisfying the conditions of the present invention was excellent in both rub resistance and adhesion to the resin after the rub test. .

Claims (7)

A roughened copper foil having a roughened surface provided with fine irregularities composed of needle-like crystals and / or plate-like crystals on at least one side, the roughened surface according to ISO25178 A roughened copper foil having a maximum height Sz to be measured of 1.5 μm or less and an arithmetic average music Spc at the peak of the mountain measured in accordance with ISO25178 of 1300 mm ⁻¹ or less.   The roughening copper foil of Claim 1 whose height of the said acicular crystal | crystallization and / or a plate-shaped crystal | crystallization is 50-400 nm.   The roughened copper foil according to claim 1 or 2, wherein the maximum height Sz is 0.2 to 1.0 µm. The roughening copper foil as described in any one of Claims 1-3 whose arithmetic mean music Spc of the said peak is 200-1000 mm < ^-1 >.   The roughening-treated copper foil as described in any one of Claims 1-4 in which the said fine unevenness | corrugation is formed through oxidation-reduction processing.   The copper clad laminated board provided with the roughening process copper foil as described in any one of Claims 1-5. The printed wiring board provided with the roughening process copper foil as described in any one of Claims 1-5.