Surface treated copper foil, copper clad laminate and printed circuit board using the same

Abstract

The present invention provides a surface-treated copper foil, wherein the treated surface forms a three-dimensional shape composed of a plurality of connected fine copper particles, and each 1m 2 The surface area ratio of the two-dimensional area is high and the anchoring effect is excellent, so it also exhibits high adhesion to the low dielectric resin substrate. Even if it is exposed to high temperature for a long time, the insulating resin substrate and the copper foil are difficult to peel off. In addition, it has excellent transmission characteristics to the same degree as the non-roughened copper foil, and can be used for high-frequency signal transmission printed circuit boards that can also produce multilayer printed circuit boards with excellent interlayer adhesion. The surface-treated copper foil of the present invention has a fine roughening treatment layer composed of copper particles with a primary particle size of 10nm to 110nm or less and a heat-resistant treatment layer containing nickel and phosphorus on at least one side of the untreated copper foil. The surface area per 1m2 calculated based on the specific surface area measured by the krypton gas adsorption BET method is 0.1447 W / m2. 2 The surface area ratio of the two-dimensional treated surface is 5.1 or more, and the amount of nickel deposited is per 1m 2 Surface area 2mg or more.

Description

Technical Field

[0001] The present invention relates to a surface-treated copper foil applicable to a printed circuit board for high-frequency signal transmission. Specifically, the present invention relates to a surface-treated copper foil having a treated surface formed into a three-dimensional shape consisting of a plurality of connected fine copper particles, with each 1 m 2 The surface area ratio of the two-dimensional area is high and the anchoring effect is excellent, so it exhibits high adhesion even to low-dielectric resin substrates. In addition, since it has a heat-resistant treated layer of dissimilar metals containing nickel and phosphorus, the copper particles are difficult to oxidize even if exposed to high temperatures for a long time, so it is difficult for protrusions to form at the interface between the insulating resin substrate and the copper foil, and it is difficult to peel off. The surface-treated copper foil has excellent transmission characteristics to the same extent as non-roughened copper foil, and can make the insulating resin substrates closely adhere to each other, so it is also possible to produce a multilayer printed wiring board with excellent interlayer adhesion. Background Art

[0002] Conventionally, various communication devices, computers, and mobile phones have used printed wiring boards in which a conductive copper wiring pattern is formed on an insulating resin substrate such as epoxy resin or polyimide resin.

[0003] In recent years, in response to the popularization of services using the fifth-generation mobile communication system (5G) or cars equipped with advanced driver assistance systems (ADAS), various devices have been developed that use high frequencies exceeding 3 GHz and very high frequency radio waves above 30 GHz, which are called millimeter waves. Along with this, the demand for printed wiring boards that support high-frequency signal transmission or multilayer printed wiring boards that also support high-speed and large-capacity transmission has increased.

[0004] When a printed circuit board transmits a high-frequency signal, the transmission characteristics deteriorate because the attenuation increases as the frequency of the signal increases.

[0005] If the printed circuit board is assumed to be a circuit with a microstrip line structure having two terminals, the transmission characteristics of the signal transmitted in the circuit can be expressed by S parameters, and the degree of signal loss between terminals caused by attenuation when the signal input from terminal 1 is output to terminal 2 is called insertion loss (S21).

[0006] Set the input power to P in , set the output power to P out , setting the unit to dB (decibel), the insertion loss (S21) is expressed by the following [Formula 1].

[0007] [Mathematical formula 1]

[0008]

[0009] For example, according to [Equation 1], relative to the input power P in 100, output power P out When the signal loss is 80%, that is, 20%, the insertion loss (S21) becomes -1.0dB. in 100,P out When the signal loss is 50, that is, 50%, the insertion loss (S21) becomes -3.0 dB. The greater the signal loss, the greater the absolute value of the insertion loss.

[0010] Generally, in order to transmit a signal, the insertion loss must be suppressed to above -3.0 dB, that is, the signal loss must be suppressed to below 50%.

[0011] However, as described above, as the frequency becomes higher, the signal loss increases, and therefore the absolute value of the insertion loss increases.

[0012] This is considered to be because the dielectric loss of the insulating resin substrate and the conductor loss of the copper foil constituting the printed wiring board are frequency dependent.

[0013] Therefore, in order to cope with the recent increase in the frequency of signals, there is an increasing demand for the development of a low-dielectric resin base material capable of further suppressing the insertion loss or a copper foil exhibiting a low conductor resistance.

[0014] Examples of the low dielectric resin substrate include polyphenylene ether resin, liquid crystal polymer resin, and fluororesin.

[0015] However, although these low-dielectric resin substrates are excellent in dielectric properties, they have a problem in that it is difficult to ensure adhesion with copper foil.

[0016] This is because the low dielectric resin substrate often uses a resin having a molecular structure with low polarity and little orientation polarization, so the intermolecular force at the interface between the insulating resin substrate and the copper foil is weakened, making it difficult to obtain chemical adhesion.

[0017] In addition, as a method for reducing the conductor resistance of copper foil, there are the following methods: reducing the surface roughness of the base material of the surface-treated copper foil, that is, the untreated copper foil, or reducing the amount of roughening treatment used to improve the physical adhesion (anchor effect) with the insulating resin substrate, and, or reducing the amount of metal treatment used to improve heat resistance.

[0018] These methods all aim to reduce the increase in transmission distance caused by the signal flowing along the uneven surface of the copper foil, by utilizing the so-called "skin effect" in which the depth of the transmitted signal becomes shallower as the frequency increases and the signal is easily transmitted near the surface.

[0019] However, if the amount of roughening treatment is reduced in order to reduce surface irregularities, the anchor effect on the insulating resin substrate is weakened, and there is a problem in that the physical adhesion at the interface between the insulating resin substrate and the copper foil is reduced.

[0020] Furthermore, when a multilayer printed wiring board is produced using a copper-clad laminate using a surface-treated copper foil with a small amount of roughening treatment, there is a problem that interlayer adhesion decreases.

[0021] This is because if, after the insulating resin substrate and the surface-treated copper foil are bonded together to produce a copper-clad laminate, the copper foil of the copper-clad laminate is etched to be completely removed, the shape of the treated surface of the copper foil is inverted and replicated on the exposed surface of the insulating resin substrate, and the convex portion on the copper foil side becomes concave on the insulating resin substrate side. However, in the multilayer printed wiring board, the insulating resin substrates are bonded to each other and become multilayered because the resin penetrates into the concave shape on the insulating resin substrate side. Therefore, if the amount of roughening treatment is reduced, the convexity and concaveness are reduced, and the concave shape for resin penetration is reduced, so that the anchoring effect is weakened.

[0022] Furthermore, if the amount of metal treatment is reduced, oxidation of the copper foil is likely to proceed when exposed to a high temperature or high humidity atmosphere, and there is a problem that protrusions are generated at the interface between the insulating resin substrate and the copper foil, which is likely to peel off.

[0023] By using a low-polarity, low-dielectric resin substrate, the decrease in adhesion or the peeling becomes more significant.

[0024] Therefore, it is desirable to develop a surface-treated copper foil that can be used for printed wiring boards for high-frequency signal transmission, which can suppress insertion loss during high-frequency signal transmission, has sufficient adhesion and heat resistance to various low-dielectric resin substrates and is difficult to peel off, and if multi-layered, can produce a multi-layer printed wiring board with excellent interlayer adhesion.

[0025] Prior art literature

[0026] Patent Literature

[0027] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-106068

[0028] Patent Document 2: WO2003 / 102277 Summary of the invention

[0029] Problem that the invention aims to solve

[0030] Patent Document 1 discloses a surface-treated copper foil which suppresses transmission loss (insertion loss) when transmitting a high-frequency signal and has excellent adhesion and durability at the interface between an insulating resin substrate and the copper foil under high temperatures or severe conditions.

[0031] The surface-treated copper foil disclosed in Patent Document 1 suppresses the height of roughened particles to be greater than 0.05 μm and less than 0.5 μm, sets the surface area ratio (ratio of three-dimensional area to two-dimensional area) of the roughened surface to be greater than 1.2, and sets the nickel content in the metal treatment layer to be 0.1 mg / dm 2 Above and below 0.3mg / dm 2 , thereby, the transmission loss is suppressed to a low level and the deterioration rate of the peel strength after long-term heating is suppressed to a low level.

[0032] However, when the surface area ratio of the surface-treated copper foil disclosed in Patent Document 1 is close to the lower limit, sufficient adhesion and heat resistance to the insulating resin substrate cannot be ensured, and interlayer adhesion when a printed wiring board is multilayered may not be ensured.

[0033] Furthermore, since the nickel content of the metallized layer is small, even if the surface area ratio is increased, the adhesion and heat resistance are weak in the temperature range exceeding 150° C., and there are problems such as protrusions occurring at the interface between the insulating resin substrate and the copper foil.

[0034] In addition, in the method disclosed in Patent Document 1, the surface area ratio of the non-roughened surface is regarded as 1, and the surface area ratio of the roughened surface is calculated by subtracting the surface area ratio 1 from the surface area ratio of the surface-treated copper foil. Therefore, if it is converted into the surface area ratio of the roughened surface and the non-roughened surface, that is, the surface area ratio of the surface-treated copper foil as a combination of the two surfaces (the surface area ratio in the present invention), it is greater than 2.2.

[0035] Patent Document 2 discloses a surface-treated copper foil that can sufficiently ensure bonding strength with a low-dielectric substrate and can minimize transmission loss.

[0036] The surface treated copper foil disclosed in Patent Document 2 forms a roughening treatment layer composed of convex copper particles with a particle size of 0.5 μm to 3.0 μm on the surface of the untreated copper foil, and ultrafine copper particles with a particle size of 0.1 μm to 1.0 μm are precipitated on the roughening treatment layer, and a rust-proof treatment layer composed of zinc-nickel is provided on the surface, and the total adhesion amount of zinc-nickel is 20 to 60 mg / m 2 The surface roughness is set to Rz1.0 μm to 6.5 μm, thereby improving the adhesion to the low dielectric substrate.

[0037] However, this method can ensure heat resistance, for example, adhesion after solder dipping or interlayer adhesion when multilayering a printed wiring board, but has a problem of increasing transmission loss (insertion loss) due to the presence of bump-shaped copper particles or the influence of ultrafine copper particles.

[0038] The present inventors set the solution of the above-mentioned problems as a technical task, and after a large number of trial and error trials and experiments, they obtained the following impressive findings and achieved the above-mentioned technical task: a surface-treated copper foil, comprising a roughening treatment layer on at least one surface of an untreated copper foil, and a heat-resistant treatment layer on the roughening treatment layer, wherein the roughening treatment layer is a fine roughening treatment layer composed of copper particles having a primary particle diameter of not less than 10 nm and not more than 110 nm, the heat-resistant treatment layer contains nickel and phosphorus, and on the treated surface of the surface-treated copper foil, the surface area per 1 m2 calculated based on the specific surface area measured by the krypton gas adsorption BET method is 0.1%; and the surface area per 1 m2 ... 2 The surface area ratio of the two-dimensional area is 5.1 or more, and the amount of nickel deposited is per 1m 2 The surface area is more than 2 mg. If it is the surface-treated copper foil, the anchoring effect is excellent, so it shows high adhesion to the insulating resin substrate and also shows high adhesion to the low-dielectric resin substrate. In addition, even if it is exposed to high temperature for a long time, it is difficult for protrusions to form at the interface between the insulating resin substrate and the copper foil, and it is difficult to peel off. The surface-treated copper foil has excellent transmission characteristics to the same extent as the non-roughened copper foil, and can make the insulating resin substrates close to each other, so it is also possible to produce a multilayer printed wiring board with excellent interlayer adhesion.

[0039] Means used to solve problems

[0040] The technical problems are as follows, which can be solved by the present invention.

[0041] The present invention is a surface-treated copper foil, which comprises a roughening treatment layer on at least one surface of an untreated copper foil, and a heat-resistant treatment layer on the roughening treatment layer, wherein the roughening treatment layer is a fine roughening treatment layer composed of copper particles having a primary particle size of 10 nm or more and 110 nm or less, the heat-resistant treatment layer contains nickel and phosphorus, and in the treated surface of the surface-treated copper foil, the surface area per 1 m2 calculated from the specific surface area measured by the krypton gas adsorption BET method is 0.0447 W / m2. 2 The surface area ratio of the two-dimensional area is 5.1 or more, and the amount of nickel deposited is per 1m 2 Surface area 2mg or more.

[0042] In addition, the present invention is the surface-treated copper foil, wherein the amount of nickel deposited is 2 Surface area less than 60 mg.

[0043] In addition, the present invention is the surface-treated copper foil, wherein the phosphorus adhesion amount is 2 Surface area 0.1 mg or more.

[0044] Moreover, the present invention is the surface-treated copper foil, wherein an arithmetic mean height Sa of the treated surface is 0.02 μm or more and 0.35 μm or less.

[0045] Moreover, the present invention provides the surface-treated copper foil, wherein a chromate treatment layer and / or a silane coupling agent treatment layer is provided on the heat-resistant treatment layer.

[0046] The present invention is a copper-clad laminate, which is obtained by laminating the surface-treated copper foil on an insulating resin substrate.

[0047] Furthermore, the present invention provides the copper-clad laminate, wherein the insulating resin substrate is a low-dielectric resin substrate.

[0048] In addition, the present invention is a printed wiring board or a multilayer printed wiring board formed using the copper clad laminate.

[0049] Effects of the Invention

[0050] The present invention is a surface-treated copper foil, wherein the roughened layer is composed of fine copper particles having a primary particle size of 10 nm to 110 nm, but the surface area per 1 m2 calculated from the specific surface area measured by the krypton gas adsorption BET method is 1.34 m2. 2 The surface area ratio of the two-dimensional area is a high surface area ratio of 5.1 or more.

[0051] Since it is composed of fine particles and has a high surface area ratio, the shape of the treated surface is as follows [ Figure 2 ]and[ Figure 3 ] as shown in the figure, it becomes a three-dimensional shape composed of multiple connected fine copper particles.

[0052] Therefore, if the treated surface and the insulating resin substrate are bonded together and heated and pressurized, the treated surface and the surface of the insulating resin substrate are three-dimensionally and closely bonded over a large area, thereby achieving an excellent anchoring effect. Therefore, it is a surface-treated copper foil with excellent adhesion to the insulating resin substrate.

[0053] The surface-treated copper foil of the present invention exhibits an excellent anchor effect and thus has excellent adhesion even to a low-dielectric resin substrate having low polarity.

[0054] In addition, as in the present invention, if the shape of the treated surface is a three-dimensional shape composed of a plurality of connected fine copper particles, the shape copied onto the surface of the insulating resin substrate after etching away the copper foil also becomes a three-dimensional surface shape equivalent to the surface shape of the surface-treated copper foil. Therefore, when a new insulating resin substrate is stacked on the surface of the insulating resin substrate after removing the copper foil, the resin penetrates into the fine concave portions with a high surface area ratio and adheres to a larger area, thereby exerting an excellent anchoring effect. This allows the manufacture of a surface-treated copper foil for a multilayer printed circuit board with excellent interlayer adhesion.

[0055] In addition, since the roughening layer is composed of fine copper particles with a primary particle size of 10nm to 110nm, it is a surface-treated copper foil that can suppress insertion loss caused by the skin effect even when transmitting high-frequency signals, and can produce a printed wiring board that can achieve the same degree of transmission characteristics as non-roughening copper foil.

[0056] In addition, the heat-resistant treatment layer of the present invention contains dissimilar metals of nickel and phosphorus, and the amount of nickel deposited is 1 m 2 The surface area is more than 2 mg, so the surface of the roughened particles is protected by nickel and phosphorus. Therefore, even if exposed to a high temperature of about 150 to 280°C for more than 1 hour, the fine copper particles are difficult to oxidize, and the generation of protrusions on the interface between the insulating resin substrate and the copper foil can be suppressed, thereby achieving high heat resistance.

[0057] Furthermore, by providing a chromate treatment layer and / or a silane coupling agent treatment layer on the heat-resistant treatment layer, the generation of protrusions at the interface between the insulating resin substrate and the copper foil can be suppressed even when exposed to a high temperature of about 300°C for more than 1 hour, thereby achieving higher heat resistance.

[0058] In addition, if the amount of nickel deposited is the above per 1m 2 When the surface area is 60 mg or less, the copper foil becomes a surface-treated copper foil from which removal of the copper foil by soft etching is easy.

[0059] In addition, if the phosphorus deposition amount is the above per 1m 2 When the surface area is 0.1 mg or more, the copper foil becomes a surface-treated copper foil from which removal of the copper foil by soft etching is easy.

[0060] Furthermore, when the arithmetic mean height Sa of the treated surface is 0.02 μm to 0.35 μm, the insertion loss due to the skin effect is further suppressed, and thus a surface-treated copper foil capable of manufacturing a printed wiring board having excellent transmission characteristics can be obtained.

[0061] Therefore, the surface-treated copper foil of the present invention can be suitably used for the production of a printed wiring board or a multilayer printed wiring board for high-frequency signal transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a schematic diagram of the surface-treated copper foil of the present invention.

[0063] Figure 2 These are scanning electron microscope photographs of the surface treated copper foil of Example 1 (surface area ratio 8.8) at 200,000 times and 100,000 times magnification.

[0064] Figure 3 These are scanning electron microscope photographs of the surface treated copper foil of Example 8 (surface area ratio 5.5) at 200,000 times and 100,000 times magnification.

[0065] Figure 4 These are scanning electron microscope photographs of the surface-treated copper foil of Comparative Example 12 (surface area ratio 5.0) at magnifications of 200,000 and 100,000.

[0066] Figure 5 These are scanning electron microscope photographs of the surface-treated copper foil of Comparative Example 11 (surface area ratio 4.2) at 200,000 times and 100,000 times magnifications.

[0067] Figure 6 This is a schematic diagram of copper particles forming the fine roughening treatment layer of the present invention. DETAILED DESCRIPTION

[0068] <Untreated copper foil>

[0069] The copper foil used in the present invention (hereinafter referred to as "untreated copper foil") is not particularly limited, and copper foils with no distinction between the front and back sides, such as rolled copper foil and electrolytic copper foil, or copper foils with distinction between the front and back sides can be used.

[0070] The surface to be surface treated is not particularly limited, and may be any surface of a rolled copper foil, or may be either the deposition surface or the drum surface of an electrolytic copper foil.

[0071] When a rolled copper foil is used, it is preferred to perform surface treatment after immersing it in a hydrocarbon-based organic solvent or an alkaline degreasing liquid to remove rolling oil.

[0072] When an electrolytic copper foil is used, it is preferred to perform surface treatment after immersing it in dilute sulfuric acid to remove the oxide film.

[0073] The thickness of the untreated copper foil is not particularly limited as long as it is a thickness that can be used for a printed wiring board after surface treatment, but is preferably 6 μm to 300 μm, and more preferably 12 μm to 35 μm.

[0074] When the arithmetic mean height Sa of either surface of the untreated copper foil is measured in accordance with JIS B 0681-3 using a confocal microscope (laser microscope) in accordance with ISO 25178-607, it is preferably 0.6 μm or less, and more preferably 0.3 μm or less.

[0075] This is because if the arithmetic mean height Sa exceeds 0.6 μm, the insertion loss may increase.

[0076] In addition, the specific surface area per 1m was calculated based on the krypton gas adsorption BET method. 2 The surface area ratio of the untreated copper foil in two-dimensional area is preferably 2-4.

[0077] <Micro-roughening treatment layer>

[0078] The present invention is a surface-treated copper foil including an untreated copper foil and a fine roughening treatment layer composed of fine copper particles.

[0079] The particle size of the primary particles of the copper particles constituting the fine roughening treatment layer is preferably 10 nm to 110 nm, and more preferably 20 nm to 100 nm.

[0080] This is because if there are many particles with a primary particle size of less than 10 nm, when the copper-clad laminate bonded to the insulating resin substrate is exposed to a high temperature of about 150 to 300°C for more than 1 hour, protrusions may be generated at the interface between the insulating resin substrate and the copper foil, and sufficient heat resistance may not be obtained. In addition, after the copper-clad laminate is used to form a printed wiring board, when the insulating resin substrate is further stacked to form a multilayer, sufficient interlayer adhesion may not be obtained.

[0081] In addition, if there are many particles having a particle diameter exceeding 110 nm, the surface roughness increases, and the insertion loss may increase.

[0082] The particle size was observed using a field emission scanning electron microscope at an inclination angle of 0° and a magnification of 100,000 to 200,000 times. Figure 6 As shown, the longest diameter of the primary particles was measured.

[0083] <Heat-resistant treatment layer>

[0084] The present invention is a surface-treated copper foil including a heat-resistant treated layer on a fine roughening treated layer.

[0085] The amount of nickel deposited in the heat-resistant treatment layer is preferably 2 The surface area is 2 mg or more, more preferably 3 mg or more.

[0086] This is because if the amount of nickel deposited is less than 2 mg, when it is bonded to an insulating resin substrate to form a copper-clad laminate, if it is exposed to a high temperature of about 150 to 300°C for more than 1 hour, protrusions may form at the interface between the insulating resin substrate and the copper foil, and sufficient heat resistance cannot be obtained.

[0087] In addition, in the process of forming blind vias on a printed wiring board, after the printed wiring board is drilled and decontaminated, when copper is plated on the inner wall or copper foil surface, the copper foil surface is degreased, pickled or soft-etched as a base treatment to improve adhesion. However, if the amount of nickel deposited exceeds 1m 2 When the surface area is 60 mg, the etching time becomes long when the copper foil surface including the fine roughening treatment layer is soft-etched, and there is a possibility that etching defects may occur and adhesion defects of the copper plating may occur.

[0088] Every 1m 2 The amount of nickel deposited on the surface area can be calculated using the following [Mathematical Formula 2].

[0089] [Mathematical formula 2]

[0090]

[0091] The amount of phosphorus deposited in the heat-resistant treatment layer is preferably 2 Surface area 0.1 mg or more.

[0092] If the deposited amount of phosphorus is less than 0.1 mg, even if the deposited amount of nickel is 60 mg or less, the etching time becomes long during soft etching, and there is a possibility that etching defects may occur and poor adhesion of copper plating may occur.

[0093] Every 1m 2 The amount of phosphorus deposited on the surface area can be calculated using the following [Mathematical Formula 3].

[0094] [Mathematical formula 3]

[0095]

[0096] The surface treated with the fine roughening treatment layer and the heat-resistant treatment layer of the present invention is calculated from the specific surface area measured by the krypton gas adsorption BET method per 1m 2 The surface area ratio of the two-dimensional area is preferably 5.1 or more, more preferably 5.5 or more.

[0097] This is because if the surface area ratio is lower than 5.1, when the copper-clad laminate bonded to the insulating resin substrate is exposed to a high temperature of about 150 to 300°C for more than 1 hour, protrusions will be generated at the interface between the insulating resin substrate and the copper foil, and sufficient heat resistance cannot be obtained. In addition, sufficient interlayer adhesion may not be obtained when multiple layers are formed.

[0098] <Calculation of surface area ratio>

[0099] The surface area ratio of the treated surface can be calculated by multiplying the krypton gas adsorption BET specific surface area measured value by the sample mass and then dividing by the sample area.

[0100] The arithmetic mean height Sa of the treated surface including the fine roughening treatment layer and the heat-resistant treatment layer of the surface-treated copper foil of the present invention is preferably 0.02 μm to 0.35 μm, more preferably 0.02 μm to 0.15 μm.

[0101] This is because if the arithmetic mean height Sa is less than 0.02 μm, the anchor effect may be weakened, and if it exceeds 0.35 μm, the insertion loss may increase.

[0102] The fine roughening treatment layer can be formed by electrolyzing the untreated copper foil while immersing it in an electrolyte solution prepared by adding 50 to 150 g / L of ethylenediamine compound to 10 to 70 g / L of copper sulfate pentahydrate with sulfuric acid or sodium hydroxide to a pH of 3 to 6.

[0103] An insoluble electrode such as platinum group oxide-coated titanium is immersed in the electrolyte as the anode, and an untreated copper foil is immersed in the opposite side as the cathode at a constant interval. The current density is 1.0 to 9.0 A / dm 2 , power 40~90C / dm 2 , the electrolysis can be carried out under the conditions of liquid temperature of 25 to 50°C.

[0104] The ethylenediamine compound added to the electrolyte solution is not particularly limited, and pentasodium ethylenediamine pentaacetate is exemplified.

[0105] The heat-resistant treated layer can be formed by electrolyzing the copper foil having the fine roughening treated layer formed on the untreated copper foil while immersing the copper foil in an electrolytic solution.

[0106] The electrolyte for forming the heat-resistant treatment layer is preferably an electrolyte prepared by adjusting the pH of an aqueous solution containing 10 to 70 g / L of a nickel-containing compound, 2 to 40 g / L of an acetate, and 0.1 to 10.0 g / L of a hypophosphite to 4.0 to 5.5.

[0107] For electrolysis, an insoluble electrode such as platinum group oxide-coated titanium is preferably immersed in the electrolyte as an anode, and a copper foil with a fine roughening treatment layer is immersed in the opposite side at a constant interval as a cathode, and the current density is 0.5 to 3.5 A / dm 2 , power 2.5~22C / dm 2 , the electrolysis is carried out under the conditions of liquid temperature of 25 to 50°C.

[0108] The nickel-containing compound contained in the electrolytic solution is not particularly limited, and examples thereof include nickel sulfate hexahydrate, nickel chloride hexahydrate, and nickel acetate tetrahydrate.

[0109] The acetate contained in the electrolyte solution is not particularly limited, but sodium acetate trihydrate is exemplified.

[0110] The hypophosphite contained in the electrolyte solution is not particularly limited, and examples thereof include disodium hydrogen phosphite, sodium hypophosphite monohydrate, and nickel hydrogen phosphite.

[0111] <Chromate treatment layer and silane coupling agent treatment layer>

[0112] The surface-treated copper foil of the present invention may be provided with a chromate treatment layer and / or a silane coupling agent treatment layer on the heat-resistant treatment layer.

[0113] By providing a chromate treatment layer and / or a silane coupling agent treatment layer on the heat-resistant treatment layer, a surface-treated copper foil having further excellent heat resistance can be obtained.

[0114] The chromate treatment layer can be formed by electrolyzing the copper foil having the heat-resistant treatment layer formed thereon while immersing the copper foil in an electrolytic solution.

[0115] The electrolyte for forming the chromate treatment layer is preferably an aqueous solution containing 10 to 60 g / L of a chromic acid compound, or an aqueous solution containing 10 to 60 g / L of a chromic acid compound and 0.2 to 4.0 g / L of zinc ions, adjusted to pH 2 to 12 using sulfuric acid or sodium hydroxide.

[0116] For electrolysis, an insoluble electrode such as platinum oxide-coated titanium is preferably immersed in the electrolyte as an anode, and a copper foil with a heat-resistant treatment layer is immersed in the opposite side at a constant interval as a cathode, and the current density is 1.0 to 5.0 A / dm 2 , power 2~6C / dm 2 , the electrolysis is carried out under the conditions of liquid temperature of 25 to 50°C.

[0117] The chromic acid-containing compound is not particularly limited, but sodium dichromate dihydrate is exemplified.

[0118] The zinc ion source is not particularly limited, but zinc oxide is exemplified.

[0119] In the present invention, a silane coupling agent treatment layer may be provided on the chromate treatment layer or the heat resistance treatment layer.

[0120] The silane coupling agent used for the silane coupling agent layer is not particularly limited, and silane coupling agents containing a vinyl group, an epoxy group, a styryl group, a methacrylate group, an acryl group, an amino group, an ureide group, and a mercapto group can be used. However, silane coupling agents containing an amino group, an epoxy group, or a vinyl group have very high effects on moisture absorption resistance and rust prevention, and can be more preferably used.

[0121] The silane coupling agents may be used alone or in combination of two or more.

[0122] The chromate treatment layer or the heat-resistant treatment layer can be formed by immersing the copper foil in an aqueous solution of a silane coupling agent prepared to a liquid temperature of 20 to 50° C., or by spraying the silane coupling agent thereon, followed by washing with water.

[0123] Examples of the composition and conditions of the aqueous solution for forming the silane coupling agent treatment layer include 1 to 5 mL / L of γ-aminopropyltriethoxysilane, a liquid temperature of 25 to 35° C., and an immersion time of 15 seconds.

[0124] <Insulating resin base material>

[0125] The insulating resin substrate to which the surface-treated copper foil of the present invention is bonded is not particularly limited, and examples thereof include epoxy resins and polyimide resins. Examples of low-dielectric resin substrates include polyphenylene ether resins, liquid crystal polymer resins, fluororesins, bismaleimide triazine resins, and cycloolefin polymer resins.

[0126] [Example]

[0127] Examples of the present invention are shown below, but the present invention is not limited thereto.

[0128] <Untreated copper foil>

[0129] As the untreated copper foil in the examples and comparative examples, an electrolytic copper foil or a rolled copper foil having a nominal thickness of 12 to 35 μm was used.

[0130] The medium rolled copper foil was immersed in an alkaline degreasing liquid to remove the rolling oil, and then subjected to various surface treatments.

[0131] In addition, the electrolytic copper foil is immersed in dilute sulfuric acid to remove the oxide film and then surface treated.

[0132] (Example 1 and Example 1a to Example 1c)

[0133] An example in which a chromate treatment layer and a silane coupling agent treatment layer are sequentially provided on a heat-resistant treatment layer is referred to as Example 1, an example in which neither a chromate treatment layer nor a silane coupling agent treatment layer is provided is referred to as Example 1a, an example in which only a chromate treatment layer is provided is referred to as Example 1b, and an example in which only a silane coupling agent treatment layer is provided is referred to as Example 1c.

[0134] <Formation of Micro-Roughening Treatment Layer>

[0135] An aqueous solution containing 35 g / L of copper sulfate pentahydrate and 100 g / L of pentasodium ethylenediamine pentaacetate at pH 4.8 and a temperature of 32°C was used as an electrolyte. An insoluble electrode of titanium coated with a platinum group oxide was immersed as an anode in the electrolyte. In addition, an untreated copper foil was immersed at a constant interval on the opposite side as a cathode. The electrolyte was stirred at a current density of 5.0 A / dm 2 , power 60C / dm 2 Electrolysis is performed under the condition of 0.5% mol / l to provide a fine roughening treatment layer on the untreated copper foil.

[0136] <Formation of Heat Resistant Treatment Layer>

[0137] As the electrolyte, an aqueous solution containing 30 g / L of nickel sulfate hexahydrate, 2.3 g / L of sodium hypophosphite monohydrate, and 10 g / L of sodium acetate trihydrate and having a pH of 4.5 and a liquid temperature of 32° C. was used.

[0138] An insoluble electrode of titanium coated with platinum oxide was immersed in the electrolyte as an anode, and a copper foil provided with the fine roughening treatment layer was immersed in the opposite side as a cathode at a constant interval, and the current density was 2.5 A / dm 2 , power 5C / dm 2 Electrolysis is performed under the condition of 0.5 % to provide a heat-resistant treated layer on the fine roughening treated layer.

[0139] <Formation of Chromate Treatment Layer>

[0140] An aqueous solution containing 12.5 g / L of sodium dichromate dihydrate and 2.5 g / L of zinc ions at pH 12 and a temperature of 25°C was used as an electrolyte, and an insoluble electrode of platinum group oxide-coated titanium was immersed in the electrolyte as an anode. In addition, a copper foil provided with the heat-resistant treatment layer was immersed in the opposite side at a constant interval as a cathode. The electrolyte was stirred at a current density of 4.3 A / dm 2 , power 6C / dm 2 Electrolysis is performed under the condition of quenching to provide a chromate treatment layer on the heat-resistant treatment layer.

[0141] <Formation of Silane Coupling Agent Treatment Layer>

[0142] The copper foil provided with the heat-resistant treatment layer or the copper foil provided with the chromate treatment layer is immersed in an aqueous solution containing 5 mL / L of γ-aminopropyltriethoxysilane at a liquid temperature of 25° C. for 10 seconds and dried to form a silane coupling agent treatment layer on the heat-resistant treatment layer or the chromate treatment layer to prepare a surface-treated copper foil.

[0143] (Example 2)

[0144] When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 10 C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0145] (Example 3 and Example 3a to Example 3c)

[0146] An example in which a chromate treatment layer and a silane coupling agent treatment layer are sequentially provided on a heat-resistant treatment layer is referred to as Example 3, an example in which neither a chromate treatment layer nor a silane coupling agent treatment layer is provided is referred to as Example 3a, an example in which only a chromate treatment layer is provided is referred to as Example 3b, and an example in which only a silane coupling agent treatment layer is provided is referred to as Example 3c.

[0147] When forming the heat-resistant treatment layer, the electrolysis condition is set to a charge of 3C / dm 2 , except for this, the production was carried out under the same conditions as in Example 1 and Example 1a to Example 1c.

[0148] (Example 4)

[0149] When forming the fine roughening treatment layer, the electrolysis condition was set to a current density of 7.0 A / dm 2 , power 80C / dm 2 When forming the heat-resistant treatment layer, the electrolysis condition is set to a charge of 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0150] (Example 5 and Example 6)

[0151] When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 10 C / dm 2 When forming the chromate treatment layer, an aqueous solution containing 20 g / L of sodium dichromate dihydrate at pH 4.5 and a liquid temperature of 25° C. was used in the electrolyte, and the electrolysis conditions were set to a current density of 2.2 A / dm 2 , power 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0152] (Example 7)

[0153] When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 20 C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0154] (Example 8)

[0155] When forming the fine roughening treatment layer, the electrolysis condition was set to a current density of 4.0 A / dm 2 , power 50C / dm 2 When forming the heat-resistant treatment layer, the electrolysis condition is set to a charge of 10C / dm 2When forming the chromate treatment layer, an aqueous solution containing 20 g / L of sodium dichromate dihydrate at pH 4.5 and a liquid temperature of 25° C. was used in the electrolyte, and the electrolysis conditions were set to a current density of 2.2 A / dm 2 , power 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0156] (Example 9)

[0157] When forming the heat-resistant treatment layer, an aqueous solution containing 30 g / L nickel sulfate hexahydrate, 0.4 g / L sodium hypophosphite monohydrate and 10 g / L sodium acetate trihydrate at pH 4.5 and a liquid temperature of 32°C was used as the electrolyte, and the electrolysis condition was set to a charge of 10 C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0158] (Example 10)

[0159] When forming the heat-resistant treatment layer, an aqueous solution containing 30 g / L nickel sulfate hexahydrate, 2.0 g / L sodium hypophosphite monohydrate, and 10 g / L sodium acetate trihydrate at pH 4.5 and a liquid temperature of 32°C was used as the electrolyte, and the electrolysis condition was set to a charge of 10 C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0160] (Example 11)

[0161] When forming the chromate treatment layer, an aqueous solution containing 20 g / L of sodium dichromate dihydrate at pH 4.5 and a liquid temperature of 25° C. was used as the electrolytic solution, and the electrolysis conditions were set to a current density of 2.2 A / dm 2 , power 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0162] (Example 12)

[0163] When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 15C / dm 2 When forming the chromate treatment layer, an aqueous solution containing 20 g / L of sodium dichromate dihydrate at pH 4.5 and a liquid temperature of 25° C. was used in the electrolyte, and the electrolysis conditions were set to a current density of 2.2 A / dm 2 , power 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0164] (Comparative Example 1)

[0165] The production was carried out under the same conditions as in Example 1 except that the fine roughening treatment layer was not provided.

[0166] (Comparative Example 2)

[0167] No fine roughening treatment layer was provided. When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0168] (Comparative Example 3)

[0169] No fine roughening treatment layer was provided. When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 10 C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0170] (Comparative Examples 4 and 5)

[0171] No fine roughening treatment layer was provided. When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 10 C / dm 2 When forming the chromate treatment layer, an aqueous solution containing 20 g / L of sodium dichromate dihydrate at pH 4.5 and a liquid temperature of 25° C. was used in the electrolyte, and the electrolysis conditions were set to a current density of 2.2 A / dm 2 , power 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0172] (Comparative Example 6)

[0173] No fine roughening treatment layer was provided. When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 20 C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0174] (Comparative Example 7)

[0175] No fine roughening treatment layer was provided. When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 6C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0176] (Comparative Example 8)

[0177] In the example of Patent Document 1, the electrolyte solution (98 g / L of copper sulfate pentahydrate, 180 g / L of sulfuric acid, 60 mg / L of molybdenum ions, liquid temperature 25° C.) and the electrolysis conditions (current density 25.0 A / dm 2 , power 38C / dm 2) to form a roughening treatment layer. In addition, when forming a heat-resistant treatment layer, an aqueous solution containing 30 g / L nickel sulfate hexahydrate, 2 g / L sodium hypophosphite monohydrate and 10 g / L sodium acetate trihydrate at pH 4.5 and a liquid temperature of 32°C was used as an electrolyte, and the current condition was set to a current density of 0.5 A / dm 2 , power 2C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0178] (Comparative Example 9)

[0179] When forming the roughening treatment layer, first, an aqueous solution containing 57 g / L of copper sulfate pentahydrate, 110 g / L of sulfuric acid, 15 mg / L of tungsten ions, and 30 mg / L of chloride ions at a temperature of 40°C was used as an electrolyte, and an insoluble electrode of platinum group oxide-coated titanium was immersed in the electrolyte as an anode, and an untreated copper foil was immersed in the opposite side as a cathode at a constant interval, and the current density was 50.0 A / dm 2 , power 125C / dm 2 Electrolysis was performed under the condition of MgO to form a dendritic particle layer on the untreated copper foil.

[0180] Next, an aqueous solution of 200 g / L of copper sulfate pentahydrate and 100 g / L of sulfuric acid at a temperature of 40°C was used as an electrolyte, and an insoluble electrode of titanium coated with a platinum group oxide was immersed as an anode in the electrolyte. In addition, a copper foil provided with a dendrite particle layer was immersed at a constant interval on the opposite side as a cathode. The electrolyte was charged at a current density of 5.0 A / dm 2 , power 440C / dm 2 The preparation was carried out under the same conditions as in Example 1, except that electrolysis was performed under 40°C to plate copper on the dendritic particle layer to provide a roughened layer.

[0181] (Comparative Example 10)

[0182] When forming the roughening treatment layer, first, an aqueous solution containing 47 g / L of copper sulfate pentahydrate, 95 g / L of sulfuric acid, 15 mg / L of tungsten ions, and 500 mg / L of titanium ions at a temperature of 35°C was used as an electrolyte, and an insoluble electrode of platinum group oxide-coated titanium was immersed in the electrolyte as an anode, and an untreated copper foil was immersed in the opposite side as a cathode at a constant interval, and the current density was 30.0 A / dm 2 、Electricity 95C / dm 2 Electrolysis was performed under the condition of MgO to form a dendritic particle layer on the untreated copper foil.

[0183] Next, an aqueous solution of 200 g / L of copper sulfate pentahydrate and 100 g / L of sulfuric acid at a temperature of 40°C was used as an electrolyte, and an insoluble electrode of titanium coated with a platinum group oxide was immersed as an anode in the electrolyte. In addition, a copper foil provided with a dendrite layer was immersed as a cathode at a constant interval on the opposite side. The electrolyte was stirred at a current density of 10.0 A / dm 2 , power 250C / dm 2 The preparation was carried out under the same conditions as in Example 1, except that electrolysis was performed under 40°C to plate copper on the dendritic particle layer to provide a roughened layer.

[0184] (Comparative Example 11)

[0185] When forming the fine roughening treatment layer, the electrolysis condition was set to a current density of 1.3 A / dm 2 , power 15C / dm 2 When forming the heat-resistant treatment layer, the electrolysis condition is set to a charge of 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0186] (Comparative Example 12)

[0187] When forming the fine roughening treatment layer, the electrolysis condition was set to a current density of 2.5 A / dm 2 , power 30C / dm 2 When forming the heat-resistant treatment layer, the electrolysis condition is set to a charge of 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0188] (Comparative Example 13)

[0189] When forming the heat-resistant treatment layer, the electrolysis condition was set to a current density of 0.5 A / dm 2 , power 1.0C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0190] (Comparative Example 14)

[0191] An aqueous solution containing 39 g / L of cobalt sulfate heptahydrate, 24 g / L of sodium molybdate dihydrate, 45 g / L of trisodium citrate dihydrate, and 40 g / L of sodium sulfate at a pH of 5.6 and a liquid temperature of 30°C was used as an electrolyte for forming a heat-resistant treatment layer. An insoluble electrode of titanium coated with a platinum group oxide was immersed in the electrolyte as an anode, and a finely roughened copper foil was immersed in the opposite side as a cathode at a constant interval. The electrolyte was heated to 7.0 A / dm 2 , power 14C / dm 2The production was carried out under the same conditions as in Example 1, except that electrolysis was carried out under the conditions of 0.05% MgCl2O3 and a heat-resistant treatment layer was provided on the copper foil.

[0192] (Comparative Example 15)

[0193] An aqueous solution containing 30 g / L nickel sulfate hexahydrate and 10 g / L sodium acetate trihydrate at pH 4.5 and a temperature of 32°C was used as an electrolyte for forming a heat-resistant treatment layer. An insoluble electrode of titanium coated with a platinum group oxide was immersed in the electrolyte as an anode. In addition, a finely roughened copper foil was immersed in the opposite side as a cathode at a constant interval. The electrolyte was heated to 10 C / dm 2 The production was carried out under the same conditions as in Example 1, except that electrolysis was carried out under the conditions of 0.05% MgCl2O3 and a heat-resistant treatment layer was provided on the copper foil.

[0194] (Comparative Example 16)

[0195] When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 24C / dm 2 When forming the chromate treatment layer, an aqueous solution containing 20 g / L of sodium dichromate dihydrate at pH 4.5 and a liquid temperature of 25° C. was used in the electrolyte, and the electrolysis conditions were set to a current density of 2.2 A / dm 2 , power 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0196] (Comparative Example 17)

[0197] When forming the heat-resistant treatment layer, the electrolysis condition was set to a charge of 27C / dm 2 When forming the chromate treatment layer, an aqueous solution containing 20 g / L of sodium dichromate dihydrate at pH 4.5 and a liquid temperature of 25° C. was used in the electrolyte, and the electrolysis conditions were set to a current density of 2.2 A / dm 2 , power 3C / dm 2 , except for this, the preparation was carried out under the same conditions as Example 1.

[0198] The surface-treated copper foils of Examples and Comparative Examples are shown in [Table 1] and [Table 2].

[0199] [Table 1]

[0200]

[0201] [Table 2]

[0202]

[0203] <Production of copper-clad laminates>

[0204] The treated surfaces of the copper foils in the examples and comparative examples were used as the bonding surfaces, and were adhesively bonded to one or six layers of polyphenylene ether resin substrates (manufactured by Matsushita Electric Industrial Co., Ltd. / MEGTRON7 / nominal thickness 0.06 mm) on one or both sides. Using a vacuum hot press (manufactured by Kitakawa Seiki Co., Ltd. / KVHC-II), heating and pressure forming were carried out for 80 minutes at a temperature of 200 °C and a surface pressure of 4 MPa in an air atmosphere to obtain copper foil laminates.

[0205] The untreated copper foils or surface-treated copper foils were evaluated by the following methods.

[0206] <Measurement of surface roughness>

[0207] Using a confocal microscope, i.e., a laser microscope (manufactured by Olympus Corporation / LEXT OLS5000) based on ISO 25178-607, in accordance with JIS B 0681-3, the arithmetic mean height Sa was measured when the evaluation area was set to 125 μm × 125 μm, the S filter was set to 0.5 μm, the filter was set to 50 μm, and the F operation was set to a multi-order surface (3rd order).

[0208] <Measurement of particle size>

[0209] For the surfaces of the examples and comparative examples provided with the micro-roughening treatment layer, using a field emission scanning electron microscope (manufactured by JEOL Ltd. / JSM-7800F), the longest diameters of 20 primary particles observed at a magnification of 100,000 to 200,000 times at an inclination angle of 0° were measured ( Figure 6 ).

[0210] <Measurement of BET specific surface area>

[0211] Using a gas adsorption amount measuring device (manufactured by Microtrack Bell Co., Ltd. / BELSORP-MaxII), after degassing under reduced pressure for 5 hours at room temperature, the krypton adsorption isotherm at liquid nitrogen temperature (77 K) was measured, and the specific surface area of each surface-treated copper foil in the examples and comparative examples was determined by the BET multi-point method.

[0212] The measurement specimens were cut out in such a way that the specimen area was 0.0150 m 2 or 0.0168 m 2 , and the mass of each specimen was used as the specimen amount.

[0213] <Calculation of surface area ratio>

[0214] The calculation was carried out by multiplying the value of the BET specific surface area by the specimen amount and dividing it by the specimen area.

[0215] <Per 1 m 2Calculation of nickel adhesion on surface area>

[0216] The surface of each surface-treated copper foil of the example and the comparative example provided with the heat-resistant treatment layer was measured with an X-ray fluorescence analyzer (ZSX Primus IV manufactured by Rigaku Corporation), and the X-ray fluorescence intensity per 1 m was calculated based on the intensity by the fundamental parameter method. 2 The nickel deposition amount of the two-dimensional area was calculated by comparing the deposition amount and surface area ratio, two-dimensional area (=1m 2 ) is substituted into [Formula 4] for calculation.

[0217] [Formula 4]

[0218]

[0219] <Every 1m 2 Calculation of phosphorus attachment on surface area>

[0220] The surface of each surface-treated copper foil of the example and the comparative example provided with the heat-resistant treatment layer was measured with an X-ray fluorescence analyzer (ZSX Primus IV manufactured by Rigaku Corporation) and the X-ray fluorescence intensity per 1 m was calculated by the fundamental parameter method. 2 The phosphorus deposition amount in the two-dimensional area was calculated by comparing the deposition amount and surface area ratio, two-dimensional area (=1m 2 ) is substituted into [Formula 5] for calculation.

[0221] [Mathematical formula 5]

[0222]

[0223] The copper-clad laminate was evaluated by the following method.

[0224] <Heat resistance test>

[0225] The treated surface of each surface-treated copper foil of the embodiment and the comparative example was used as the bonding surface and matched to the double sides of 6 laminated polyphenylene ether resin substrates (Manufactured by Panasonic Corporation / MEGTRON7 / nominal thickness 0.06 mm), and a vacuum hot press (Manufactured by Kitagawa Seiki Co., Ltd. / KVHC-II) was used to heat and press-form for 80 minutes at a temperature of 200°C and a surface pressure of 4 MPa in an atmospheric atmosphere to obtain a double-sided copper-clad laminate.

[0226] According to JIS C6481, each double-sided copper-clad laminate was cut into 5 cm×5 cm pieces, and five of them were used as test pieces. They were kept at 260° C. and 280° C. for 1 hour in a thermostatic chamber with air circulation function in an atmospheric atmosphere.

[0227] Each test piece after the heat resistance test at each temperature was visually observed, and the number of test pieces in which peeling occurred at the interface between the resin substrate and the copper foil was counted and evaluated as follows.

[0228] ○: The number of test pieces peeled off at a temperature of 280°C or less is 0

[0229] ×: The number of test pieces peeled off at a temperature of 280°C or less was 1 to 5

[0230] The examples and comparative examples provided with the chromate treatment layer and the silane coupling agent treatment layer were kept at 290° C. for 1 hour, and the number of peeled test pieces was counted.

[0231] <Interlayer Adhesion Test>

[0232] The treated surface of each surface-treated copper foil of the embodiment and the comparative example was used as the bonding surface. First, it was matched with a single surface of a polyphenylene ether resin substrate (manufactured by Panasonic Corporation / MEGTRON7 / nominal thickness 0.06 mm), and a vacuum hot press (manufactured by Kitagawa Seiki Co., Ltd. / KVHC-II) was used to heat and press-form at a temperature of 200°C and a surface pressure of 4 MPa for 80 minutes in an atmospheric atmosphere to obtain a single-sided copper-clad laminate.

[0233] Next, the copper foil portion of the single-sided copper-clad laminate is fully etched using a cupric chloride etching solution, and the laminate is washed with water and dried. Furthermore, a sheet of the polyphenylene ether resin substrate is matched to the etched surface of the copper foil, and a vacuum press (KVHC-II manufactured by Kitagawa Seiki Co., Ltd.) is used to heat and press the laminate under the conditions to produce a pseudo-multilayer board.

[0234] Each pseudo multilayer board was cut into five pieces of 5 cm×5 cm as test pieces, and pre-treated by boiling in pure water for 6 hours, and then vertically immersed in a solder bath at 288° C. for 30 seconds.

[0235] Each test piece after the interlayer adhesion test was visually observed, and the number of test pieces in which peeling occurred at the interface between the insulating resin substrates was counted and evaluated as follows.

[0236] 0:0

[0237] ×: 1 to 5

[0238] <Transmission Characteristics>

[0239] The treated surface of each surface-treated copper foil of the embodiment and the comparative example was used as the bonding surface and matched to both sides of a polyphenylene ether resin substrate (manufactured by Panasonic Corporation / MEGTRON7 / nominal thickness 0.06 mm). A vacuum hot press (manufactured by Kitagawa Seiki Co., Ltd. / KVHC-II) was used to heat and press-form for 80 minutes at a temperature of 200°C and a surface pressure of 4 MPa in an atmospheric atmosphere to obtain a double-sided copper-clad laminate.

[0240] A single-ended microstrip circuit was formed on the obtained double-sided copper-clad laminate using an etching apparatus (SPE-40 manufactured by Ninomiya Seisakusho Co., Ltd.) to prepare a test piece.

[0241] In addition, the test piece was set to have a circuit length of 100 mm, a circuit width of 190 μm, and a characteristic impedance of 50Ω.

[0242] The S parameter (S21) at a frequency of 20 GHz was measured using a network analyzer (E5071C manufactured by Keysight Technologies), and the test piece was evaluated as follows.

[0243] 〇:-3dB / 100mm or more

[0244] ×: less than -3dB / 100mm

[0245] <Overall Evaluation>

[0246] The heat resistance test, the interlayer adhesion test, and the transmission characteristics were comprehensively evaluated and evaluated as follows.

[0247] ○: When any of the evaluations in the above tests are 0

[0248] ×: When there are 1 or more × evaluations in the above test

[0249] Evaluation simulating through-hole formation of a printed wiring board was performed as follows.

[0250] <Soft Etching Properties>

[0251] The soft etching property was evaluated as the removability evaluation of the copper foil surface including the fine roughening treatment layer by simulating the base treatment of the copper foil surface in the process of forming a blind via in a printed wiring board.

[0252] The surface-treated copper foils of Examples 9 to 12 and Comparative Examples 15 to 17 were cut into pieces of 5 cm×5 cm in size, and heated at 300° C. for 100 seconds in an air atmosphere to prepare test pieces.

[0253] The soft etching solution used was an aqueous solution at a temperature of 40° C. containing 200 mL of sulfuric acid and 25 mL / L of hydrogen peroxide. Each test piece was immersed in the soft etching solution, and the time (seconds) from when the fine roughening treatment layer was dissolved until the substrate (untreated copper foil) of the treated copper foil could be visually observed was measured. Evaluation was performed as follows.

[0254] ◎: Less than 30 seconds

[0255] 0: 30 seconds or more and less than 60 seconds

[0256] △: 60 seconds or more and less than 120 seconds

[0257] ×: More than 120 seconds

[0258] The results of heat resistance, interlayer adhesion, and transmission characteristics of each surface-treated copper foil of the examples and comparative examples are shown in [Table 3] to [Table 6].

[0259] The results of the soft etching properties of each surface-treated copper foil of Examples and Comparative Examples are shown in [Table 7].

[0260] [Table 3]

[0261]

[0262] [Table 4]

[0263]

[0264] [Table 5]

[0265]

[0266] [Table 6]

[0267]

[0268] [Table 7]

[0269]

[0270] Examples 1 to 8 demonstrate that the surface-treated copper foil of the present invention has an insertion loss of -3 dB / 100 mm or more even at a high frequency of 20 GHz, which is the same as that of the non-roughened foil (Comparative Examples 1 to 7), and that the copper-clad laminate using the surface-treated copper foil of the present invention has high heat resistance such that no peeling occurs at the interface between the insulating resin substrate and the copper foil even when heated at 280° C. for 1 hour.

[0271] Furthermore, it was demonstrated that even when a new insulating resin base material was laminated on the copper-etched surface of the copper-clad laminate using the surface-treated copper foil of the present invention, excellent interlayer adhesion was achieved.

[0272] Furthermore, it was confirmed from Examples 9 to 12 that the soft etching time of the surface-treated copper foil of the present invention was less than 60 seconds, and that excellent soft etching properties were exhibited.

[0273] Industrial Applicability

[0274] The surface-treated copper foil of the present invention is a surface-treated copper foil in which the roughening treatment layer is formed into a three-dimensional shape consisting of a plurality of connected fine copper particles, with a thickness of 1 m 2 The two-dimensional surface area ratio is high and the anchoring effect is excellent, so it exhibits high adhesion even to low-dielectric resin substrates with low polarity. In addition, since it has a heat-resistant treated layer of dissimilar metals containing nickel and phosphorus, it is difficult to produce protrusions at the interface between the insulating resin substrate and the copper foil even if exposed to high temperatures for a long time, and it is difficult to peel off.

[0275] In addition, the present invention is a surface-treated copper foil that can suppress insertion loss to the same level as non-roughened copper foil, so it has excellent transmission characteristics, and can make insulating resin substrates closely adhere to each other, so if it is multilayered, it can produce a multilayer printed wiring board with excellent interlayer adhesion, so it is suitable for printed wiring boards for high-frequency signal transmission.

[0276] Therefore, the present invention has high industrial applicability.

Claims

1. A surface-treated copper foil, comprising a roughening treatment layer on at least one surface of an untreated copper foil, and a heat-resistant treatment layer on the roughening treatment layer, wherein: The roughening treatment layer is a fine roughening treatment layer composed of copper particles having a primary particle diameter of 10 nm or more and 110 nm or less. The heat-resistant treatment layer contains nickel and phosphorus. In the treated surface of the surface-treated copper foil, the surface area per 1 m2 is calculated based on the specific surface area measured by the krypton gas adsorption BET method. 2 The surface area ratio of the two-dimensional area is 5.1 or more, and the amount of nickel deposited is per 1m 2 Surface area 2mg or more.

2. The surface-treated copper foil according to claim 1, wherein The amount of nickel deposited is per 1m 2 Surface area less than 60 mg.

3. The surface-treated copper foil according to claim 1 or 2, wherein The phosphorus attachment amount is per 1m 2 Surface area 0.1 mg or more.

4. The surface-treated copper foil according to claim 1 or 2, wherein The arithmetic mean height Sa of the processed surface is greater than or equal to 0.02 μm and less than or equal to 0.35 μm.

5. The surface-treated copper foil according to claim 1 or 2, wherein A chromate treatment layer and / or a silane coupling agent treatment layer is provided on the heat-resistant treatment layer. 6 . A copper-clad laminate, comprising the surface-treated copper foil according to claim 1 bonded to an insulating resin substrate.

7. The copper-clad laminate according to claim 6, wherein: The insulating resin substrate is a low dielectric resin substrate.

8. A printed wiring board or a multilayer printed wiring board formed using the copper-clad laminate according to claim 6 or 7.

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