TW202043034A - Laminate - Google Patents

Abstract

The purpose of the present invention is to provide a novel laminate of a composite copper member and a resin substrate. According to the present invention, there is provided a laminate in which, on a copper member having a plurality of fine protrusions on at least part of a surface, a resin substrate having a dielectric constant of 3.8 or less is laminated on the surface, wherein the fractal dimension of the laminated surfaces of the copper member and the resin substrate is 1.25 or higher.

Description

Layered body

The present invention relates to a laminate.

The copper foil used in the printed wiring board needs adhesion to the insulating resin substrate. In order to improve the adhesion, there has been a method of roughening the surface of the copper foil by etching or the like, that is, by using the so-called anchor effect to improve the mechanical adhesion. However, from the viewpoint of increased density of printed wiring boards or transmission loss in high frequency bands, the surface of the copper foil needs to be flattened. In order to meet the above-mentioned opposite requirements, a copper surface treatment method that performs an oxidation step and a reduction step has been developed (refer to Patent Document 1). According to this method, the copper foil is pre-treated and immersed in a potion containing an oxidizing agent to oxidize the surface of the copper foil to form copper oxide bumps and then immersed in a potion containing a reducing agent to reduce the copper oxide, thereby adjusting the surface Concave and convex to adjust the surface roughness. In addition, a method of adding interfacial active molecules in the oxidation step has been developed as a method of improving the adhesion of copper foil treatment by oxidation and reduction (see Patent Document 2), and the use of aminothiazole compounds in the copper foil after the reduction step A method of forming a protective film on the surface of the foil (refer to Patent Document 3). In addition, another method has been developed to roughen the surface of the copper conductor pattern on the insulating substrate to form a plating film with dispersed metal particles on the surface where the copper oxide layer is formed (see Patent Document 4).

Generally speaking, the adhesion between resin and metal, in addition to the above-mentioned mechanical adhesion, is also related to 1) the physical bonding force generated by the intermolecular force between the resin and the metal or 2) the functional group of the resin and the metal. It is related to the chemical binding force produced by covalent bonds. In order to achieve low permittivity and low dissipation factor, the insulating resin used in high-frequency circuits reduces the proportion of OH groups (hydroxyl groups). However, the OH group of the resin is related to the bond with the metal, which leads to the chemical properties of copper foil. Sexual binding power becomes weaker (refer to Patent Document 5). Therefore, the adhesion between insulating resin and copper foil for high-frequency circuits requires stronger mechanical adhesion.

Patent Document 1 is International Publication No. WO2014/126193; Patent Document 2 is Japanese Patent Application Publication No. 2013-534054; Patent Document 3 is Japanese Patent Application Laid-open No. 8-97559; Patent Document 4 is Japanese Patent Application Publication No. 2000-151096 ; Patent Document 5 is International Publication WO2017/150043 Bulletin.

The object of the present invention is to provide a novel laminate of a composite copper member and a resin substrate.

As a result of intensive research by the inventors, they succeeded in producing a novel laminate of a composite copper member and a resin substrate, which has excellent peel strength and heat resistance. The present invention has the following implementation aspects: [1] A laminate in which a resin substrate having a permittivity of 3.8 or less is laminated on the surface of a copper member having a plurality of fine protrusions on at least a part of the surface, and the laminate layer of the copper member and the resin substrate The fractal dimension is above 1.25. [2] As in [1], the fractal dimension of the layer is larger than 1.4. [3] The laminate according to [1] or [2], wherein at least a part of the surface of the copper member includes a copper oxide layer. [4] The laminate as in [1] or [2], wherein at least a part of the surface of the copper member is formed of a metal layer other than copper, and the metal other than copper is selected from tin, silver, zinc, and aluminum , Titanium, bismuth, chromium, iron, cobalt, nickel, palladium, gold and platinum at least one metal. [5] The laminate according to [4], wherein the average thickness in the vertical direction of the metal layer other than copper is 10 nm or more and 150 nm or less. [6] The laminated body according to any one of [1] to [5], wherein the average height of the convex portion in the vertical cross section of the laminated body is 50 nm or more and 500 nm or less. [7] The layered body according to [6], wherein the vertical cross section of the layered body has an average of 30 or more convex portions per section width of 3.78 μm. [8] The laminate according to any one of [1] to [7], wherein the resin substrate contains polyphenylene ether, polytetrafluoroethylene, or a liquid crystal polymer containing p-hydroxybenzoic acid. [9] The laminate according to [8], wherein the peeling mode is cohesive failure when the resin base material and the copper member are peeled off. [10] The laminate as in [9], wherein the deterioration rate in the heat resistance test is 50% or less. [11] The laminate as described in any one of [1] to [10], wherein the laminate is used for high-frequency circuits above 1 GHz. [12] An electronic component, which is produced using a laminate as in any one of [1] to [11].

The preferred embodiment of the present invention will be described in detail below using additional drawings, but it is not limited thereto. In addition, based on the description in this specification, those with ordinary knowledge in the technical field to which the invention pertains can understand the purpose, features, advantages, and concept of the present invention, and those with ordinary knowledge in the technical field to which the invention pertains can easily reproduce from the description in this specification. this invention. The embodiments and specific examples of the invention described below represent preferred embodiments of the invention, and are used for illustration and description, and do not limit the invention. Those having ordinary knowledge in the technical field to which the invention pertains will understand that various modifications can be made based on the description of this specification within the intent and scope of the invention disclosed in this specification.

Laminated body: One aspect of the present invention is a laminated body. A resin base material with a permittivity of 3.8 or less is laminated on a copper member with several fine protrusions on the surface. It is preferable that the copper member and the resin substrate are closely adhered. For example, in the scanning electron microscope (SEM) cross-sectional image (30000 times magnification, 1024×768 resolution) of the cross-sectional image of the laminated body produced by the focused ion beam (FIB), the copper member and the resin base are preferred. The degree of voids cannot be detected between the layers of the material.

The copper member includes copper foil such as electrolytic copper foil and rolled copper foil, copper wire, copper plate, copper lead frame, etc., but is not limited to this. A copper component is a component that contains more than 50% by mass of copper, that is, the material that forms part of the structure. It can include copper alloys (that is, cupronickel, brass, aluminum bronze, etc.) or materials coated with copper (such as copper-plated Iron), preferably a material made of pure copper with a copper purity of 99.9% by mass or more, more preferably made of toughened copper, deoxidized copper, and oxygen-free copper, and preferably with an oxygen content of 0.001% to 0.0005% by mass The formation of oxygen-free copper.

The resin substrate is not particularly limited, and may include a thermoplastic resin or a thermosetting resin. Specifically, for example, polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) , Polyvinyl acetate (PVAc), polyamide (PA), polyoxymethylene (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE), polystyrene containing polystyrene polymers Ether, polymer or copolymer of triallyl cyanurate, phenolic addition butadiene polymer, diallyl phthalate, divinylbenzene, polyfunctional methacrylic acid Acetone-based resin, unsaturated polyester, polybutadiene, styrene-butadiene, styrene-butadiene‧ styrene-butadiene cross-linked polymer, bismaleimide triazine (BT ), polyethylene terephthalate (PET), glass fiber reinforced polyethylene terephthalate (GF-PET), polybutylene terephthalate (PBT), cyclic polyolefin (COP) , Polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfide (PSF), polyether sulfide (PES), amorphous polyarylate (PAR), liquid crystal polymer (LCP) (for example, containing p-hydroxy Condensation polymers of benzoic acid and ethylene terephthalate; condensation polymers of p-hydroxybenzoic acid, phenol and phthalic acid; condensation polymers of p-hydroxybenzoic acid and 2,6-hydroxynaphthoic acid, etc.), Polyetheretherketone (PEEK), thermoplastic polyimide (PI), polyimide imine (PAI) and base materials containing mixtures of these. The resin substrate may further include inorganic fillers or glass fibers. The permittivity of such a resin substrate can be measured by a conventional method, for example, it can be measured according to specifications such as IPC TM (The Institute for Interconnecting and Packaging Electronic Circuits Test Method)-650 2.5.5.5 or IPC TM-650 2.5.5.9. An example of the resin base material can be MEGTRON 6 (manufactured by Panasonic Corporation, with a permittivity of 3.71) composed of 20 to 70% by weight of polyphenylene ether (PPE), 0 to 20% by weight of silica, and 30 to 70% of glass fiber. (1GHz)).

The laminated surface of the resin base material and the metal layer preferably has several fine convex portions. The shape of the convex part can be defined as the fractal dimension or the radius of the inscribed circle of the top end of the convex part. The fractal dimension can be calculated as the fractal dimension of the curve displayed on the product plane from the cross-sectional image produced by the focused ion beam (FIB) using a scanning electron microscope (SEM). For example, the fractal dimension can be calculated by box-counting, but the calculation method is not limited to this. The radius of the inscribed circle at the tip of the convex part can be calculated by measuring the convex part in the cross-sectional image produced by the focused ion beam (FIB) using a scanning electron microscope (SEM).

The fractal dimension is an index indicating the complexity of the shape, the degree of surface unevenness, etc. The larger the value of the fractal dimension, the more complicated the unevenness. For example, the fractal dimension calculated by the box calculation method is defined as follows: the number of boxes required to cover a certain figure F with a square box with side length δ is set to Nδ(F), then the fractal dimension is defined by the following formula.

In the present invention, the cross section of the layered body is divided into grids of equal intervals δ, and the number of boxes (that is, squares resulting from the division of the grid) that contain the curve of the layer surface is calculated with respect to several δ. Next, draw a double logarithmic graph with the size of δ as the horizontal axis and the number of boxes calculated relative to several δ as the vertical axis, and the fractal dimension can be obtained from the slope of the graph.

More specifically, the outline of the fine convex part obtained from the SEM cross-sectional image (30000 times magnification, 1024×768 resolution) is pasted to a slice with a resolution of 256, 128, 64, 32, 16 or 8 pixels, and the calculation includes The number of grids of the outline. Using the logarithmic value of the pixel size as the vertical axis and the logarithmic value of the grid number as the horizontal axis, draw the calculated grid number relative to each pixel size to make an approximate straight line, and calculate the value of the fractal dimension from its slope. The value of the fractal dimension of the curve displayed on the product level is 1.250 or greater or greater than 1.250, preferably 1.300 or greater or greater than 1.300, more preferably 1.350 or greater or greater than 1.350, and more preferably 1.400 The above or a value greater than 1.400.

In one aspect of the present invention, the surface of the copper member may include a copper oxide layer, and the copper oxide layer contains copper (I) oxide and/or copper (II) oxide. The copper oxide layer can be formed by oxidation treatment, oxidation dissolution treatment, oxidation reduction treatment, and oxidation dissolution reduction treatment. The oxidation treatment includes a step of converting pure copper into copper (II) oxide with an oxidizing agent. The dissolution treatment includes a step of dissolving the copper (II) oxide oxidized through the oxidation treatment by a dissolving agent. The reduction treatment includes a step of reducing the copper (II) oxide oxidized by the oxidation treatment to copper (I) oxide or pure copper by a reducing agent. The oxidation treatment, the dissolution treatment, and the reduction treatment may include a step of forming fine protrusions (ie, fine hairs) on the surface of the copper member, and a step of adjusting the shape and number of the fine protrusions. The several fine protrusions on the laminated surface of the resin substrate and the metal layer can be derived from the fine protrusions formed by these processes.

A metal layer other than copper may be formed on at least a part of the surface of the copper member. When the copper oxide layer is formed, the metal layer is formed on at least a part of the surface of the copper oxide layer, and at least a part of the surface of the metal layer is preferably laminated with a resin substrate having a permittivity of 3.8 or less. The type of metal constituting the metal layer is not particularly limited, and preferably is at least one metal selected from the group consisting of tin, silver, zinc, aluminum, titanium, bismuth, chromium, iron, cobalt, nickel, palladium, gold and platinum . In particular, in order to have heat resistance, it is preferable to use metals having higher heat resistance than copper, such as nickel, palladium, gold, and platinum.

The average thickness of the metal layer in the vertical direction is not particularly limited, but is preferably 6 nm or more, more preferably 10 nm or more, 14 nm or more, 18 nm or more, or 20 nm or more. However, if it is too thick, the fine convex portions on the surface of the composite copper member will be smoothed due to the leveling effect, and the value of the fractal dimension will decrease and the adhesion force will decrease. Therefore, it is preferably 150nm or less, more preferably 100nm or less or 75nm or less . The thickness measurement method can, for example, dissolve the copper member in 12% nitric acid, and use the ICP emission spectrometer 5100 SVDV ICP-OES (manufactured by Agilent Technologies) to measure the concentration of the metal component in the resulting solution by considering the metal density and the surface area of the metal layer. To calculate the thickness of the layered metal layer.

The metal layer can be formed on the surface of the copper component by plating. The plating method is not particularly limited, and examples include electroplating, electroless plating, vacuum evaporation, chemical conversion treatment, etc., and electroplating is preferred.

In one aspect of the present invention, in the SEM cross-sectional image of the laminate, the average height of the convex portion of the curve that appears on the laminate layer is preferably 10 nm or more, more preferably 50 nm or more, more preferably 100 nm or more, and more preferably It is 1000 nm or less, more preferably 500 nm or less, and still more preferably 200 nm or less. The height of the convex portion is, for example, the distance between the midpoint of the line connecting the minimum points of the concave portions adjacent to the convex portion and the maximum point of the convex portion existing between the concave portions in the SEM cross-sectional image. In one aspect of the present invention, in the SEM cross-sectional image of the laminate, the height of the curve appearing on the laminate surface is the number of protrusions above 50 nm, and there may be an average of 25, 30, or 35 or more per section width of 3.78 μm. Alternatively, protrusions with a height of 100 nm or more may have an average of 6, 10, or 12 or more per section width of 3.78 μm. Alternatively, the protrusions with a height of 150 nm or more may have an average of 2 or 3 or more per section width of 3.78 μm. The higher the height of the convex portion, the greater the mechanical adhesion produced by the anchoring effect, so it is better from the viewpoint of peel strength, but the influence of the skin effect increases. The skin effect is a phenomenon in which the current flowing through the conductor concentrates on the surface of the conductor as the frequency increases, and the current density inside decreases. The thickness of the part of the skin through which the current flows (skin depth) is inversely proportional to the square root of the frequency. Due to this skin effect, when high-frequency signals with frequencies in the GHz band are transmitted to the conductor circuit, the skin depth is about 2 μm or less, and current flows only on the extreme surface of the conductor. Therefore, in a high-frequency circuit, if the convex portion on the surface of the copper member is large, the transmission path of the conductor formed by the copper member becomes longer due to the skin effect, increasing the transmission loss. Therefore, the convex portion on the surface of the copper member used in the high-frequency circuit is preferably small, but if it is too small, sufficient peel strength cannot be obtained, so it is preferable to have the convex portion of the above degree.

The radius of the inscribed circle at the tip of the convex part in this specification can be used as an indicator of the thickness of the convex part. Here, the inscribed circle radius of the tip of the fine convex portion is defined as the SEM cross-sectional image, the maximum point a of the convex portion with a height of 10 nm or more, the straight line parallel to the tangent line of the maximum point a of the convex portion and spaced by 10 nm and The intersection points b and c of the outer periphery of the convex part are the three points a, b, and c as the radius of the outer circle (Figure 2A). The larger the radius of the inscribed circle, the thicker the tip of the convex portion, and the smaller the radius of the inscribed circle, the thinner the tip of the convex portion.

In one aspect of the present invention, when the resin substrate and the composite copper member are peeled off, at least a part of the failure mode of the peeling surface on the side of the composite copper member is preferably cohesive failure. Here, the cohesion failure means that when the copper side of the peeling surface is observed, about half or more of the area is in a state where the resin is attached.

In one aspect of the present invention, the degradation rate of the laminate in the heat resistance test may be 50% or less, preferably 40% or less, 30% or less, or 20% or less. The degradation rate of the heat resistance test can be measured by conventional methods. For example, it may be a ratio obtained by measuring the peel strength before and after the heat resistance test, and dividing the difference in peel strength by the peel strength before the heat resistance test. The heat resistance test can be measured in accordance with the specifications of IPC TM-650 2.4.8, for example.

Manufacturing method of laminated body: One embodiment of the present invention is a method of manufacturing a laminated body, which may include a first step and a third step. The first step is to form protrusions on the surface of the copper member, and the third step is to form protrusions on the surface of the copper member. On the copper surface of the part or the surface after plating treatment, the resin substrate is heated and adhered. This manufacturing method may include a second step after the first step, which is to perform a plating treatment on the copper surface on which the protrusions are formed.

First, in the first step, the copper surface is oxidized with an oxidizing agent to form a copper oxide layer, and convex portions are formed on the surface. Before this oxidation step, roughening treatment steps such as etching are not required, but it can be performed. Before oxidation treatment, degreasing treatment or alkali treatment can also be carried out to prevent acid from being carried into the oxidation step. The method of alkali treatment is not particularly limited, preferably 0.1-10g/L alkaline aqueous solution, more preferably 1-2g/L alkaline aqueous solution, alkaline aqueous solution such as sodium hydroxide aqueous solution, treated at 30-50℃ for 0.5 ~2 minutes is enough.

The oxidizing agent is not particularly limited. For example, aqueous solutions such as sodium chlorite, sodium hypochlorite, potassium chlorate, potassium perchlorate, and potassium persulfate can be used. Various additives (such as phosphate such as trisodium phosphate dodecahydrate) or surface active molecules can be added to the oxidizer. Surface-active molecules include, for example, porphyrin, porphyrin macrocycles, expanded porphyrin, condensed porphyrin, porphyrin linear polymer, porphyrin-sandwich coordination complex, porphyrin array, silane, tetraorgano-silane , Aminoethyl-aminopropyl-trimethoxysilane, (3-aminopropyl)trimethoxysilane, (1-[3-(trimethoxysilyl)propyl]urea) (l- [3-(Trimethoxysilyl)propyl]urea), (3-aminopropyl)triethoxysilane, (3-epoxypropyloxypropyl)trimethoxysilane, (3-chloropropyl)trimethoxy Silane, (3-epoxypropyloxypropyl)trimethoxysilane, dimethyldichlorosilane, 3-(trimethoxysilyl)propyl methacrylate, ethyltriethoxysilane , Triethoxy (isobutyl) silane, triethoxy (octyl) silane, ginseng (2-methoxyethoxy) (vinyl) silane, chlorotrimethylsilane, methyltrichlorosilane , Silicon tetrachloride, tetraethoxysilane, phenyltrimethoxysilane, chlorotriethoxysilane, vinyl-trimethoxysilane, amine, sugar, etc.

The oxidation reaction conditions are not particularly limited, and the liquid temperature of the oxidizing agent is preferably 40 to 95°C, more preferably 45 to 80°C. The reaction time is preferably 0.5 to 30 minutes, more preferably 1 to 10 minutes.

In the first step, a dissolving agent can be used to dissolve the surface of the oxidized copper component to adjust the unevenness of the surface of the oxidized copper component.

The dissolving agent used in this step is not particularly limited. It is preferably a chelating agent, especially a biodegradable chelating agent, such as ethylenediaminetetraacetic acid, dihydroxyethylglycine, L-glutamic acid diacetic acid Sodium, ethylenediamine-N,N'-disuccinic acid, sodium 3-hydroxy-2,2'-imino disuccinate, trisodium methylglycine diacetate, tetrasodium aspartate diacetate , N-(2-hydroxyethyl) iminodiacetate, sodium gluconate, etc.

The pH value of the dissolving agent is not particularly limited, and is preferably alkaline, more preferably pH 8.0 to 10.5, still more preferably pH 9.0 to 10.5, and more preferably pH 9.8 to 10.2.

In addition, in the first step, a chemical solution containing a reducing agent (reduction chemical solution) can be used to reduce the copper oxide layer formed on the copper member to adjust the number or height of the protrusions.

The reducing agent can be DMAB (dimethylamine borane), diborane, sodium borohydride, hydrazine, etc. In addition, the chemical solution for reduction is a liquid containing a reducing agent, an alkaline compound (sodium hydroxide, potassium hydroxide, etc.), and a solvent (pure water, etc.).

Next, in the second step, the copper oxide layer having the convex portion is plated with a metal other than copper to produce a composite copper component. Conventional techniques can be used for the plating treatment method. For example, tin, silver, zinc, aluminum, titanium, bismuth, chromium, iron, cobalt, nickel, palladium, gold, platinum or various alloys can be used for metals other than copper. The plating step is also not particularly limited, and plating can be performed by electroplating, electroless plating, vacuum evaporation, chemical conversion treatment, or the like.

In the case of electroless nickel plating, it is preferable to use a catalyst for treatment. The catalyst can use iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and these salts. By using a catalyst for treatment, a uniform metal layer with no particles dispersed everywhere can be obtained. This improves the heat resistance of the composite copper component. The reducing agent used in the case of electroless nickel plating is preferably copper, copper oxide (I), and copper oxide (II) without catalyst activity. Copper, copper oxide (I), and copper oxide (II) have no catalytic activity as reducing agents, for example, hypophosphites such as sodium hypophosphite.

For the composite copper components manufactured by these steps, coupling treatment using silane coupling agent, etc. or anti-rust treatment using benzotriazoles, etc. can be performed.

The third step is to laminate a resin base material on the copper oxide layer having the protrusions formed in the first step or on the plating layer of the copper member plated in the second step to produce a laminate. The manufacturing method of the laminate is not particularly limited, and it can be performed by a conventional method such as vacuum heating and pressing with a vacuum press. The pressing pressure, temperature, and pressing time can be appropriately changed according to the resin substrate used. For example, when the resin substrate is MEGTRON6 (Panasonic) containing PPE resin, it is recommended to heat and press at 0.49 MPa while heating to 110°C, and then heat and press at 2.94 MPa at 210°C for 120 minutes. In the case of NX9255 (Park Electrochemical Company) containing PTFE resin, it is recommended to heat to 260°C while heating and pressing at 0.69MPa, and then heating to 385°C while pressing at 1.03MPa to 1.72MPa, and press at 385°C. The heat pressing treatment is performed at ℃ for 10 minutes, but it is not limited to this. The high-frequency circuit-oriented resin substrate with a permittivity of 3.8 or less has a tendency to become higher when the pressure temperature is higher than that of a wiring board oriented resin substrate with a permittivity higher than 3.8 (such as FR-4), and the fine unevenness is more A state that is easy to change. Copper will be affected by heat, but the smaller the unevenness, the greater the impact. This is because when the same degree of heat changes, the smaller the affected object, the greater the degree of influence. For example, in the case of fine unevenness, the uneven shape may be damaged after pressing, and sufficient peel strength may not be exhibited. Therefore, the uneven portion is required to have an uneven shape that can withstand the temperature during pressing and can exhibit sufficient peel strength after being laminated.

In this way, by performing the first to third steps on the copper member, a novel laminate of the copper member and the resin substrate can be produced. In addition, the copper member used for the laminate can be patterned by a conventional method (for example, etching). The laminate of the present invention can be used for the manufacture of printed wiring boards, or can also be used for the manufacture of electronic parts including printed wiring boards and electronic parts. The printed wiring board manufactured using this laminate is particularly suitable as a substrate for high frequency bands with a signal frequency of 1 GHz or more. In addition, since this build-up system has uneven shapes on the build-up surface, it has excellent adhesion and is also suitable for flexible substrates.

(Examples) <1. Manufacturing laminate>: Examples 1 and 2 and Comparative Examples 1 and 2 used DR-WS (manufactured by Furukawa Electric Co., Ltd., thickness 18 μm) as copper foil.

(1) Pretreatment: [Alkaline degreasing treatment] After immersing the copper foil in a 40g/L sodium hydroxide aqueous solution at a liquid temperature of 50°C for 1 minute, it is washed with water. [Pickling treatment] The copper foil subjected to alkali degreasing treatment was immersed in a 10% by weight sulfuric acid aqueous solution at a liquid temperature of 25°C for 2 minutes, and then washed with water. [Pre-soaking treatment] Pre-soaking with 1.2g/L sodium hydroxide aqueous solution at 40°C for 1 minute. This is used for degreasing and cleaning, and its purpose is to reduce the unevenness of oxidation treatment.

(2) Oxidation treatment: For the alkali-treated copper foil, oxidation treatment is carried out at 45°C for 1 minute with an oxidation treatment aqueous solution (NaClO ₂ 130g/L; NaOH 12g/L). After these treatments, the copper foil is washed with water. In Comparative Example 1 and Comparative Example 2, after the oxidation treatment, they were immersed in a reducing agent (dimethylamine borane 5 g/L; sodium hydroxide 5 g/L) at room temperature for 1 minute to perform the reduction treatment.

(3) Plating treatment: In Example 1 and Example 2, electroplating was applied to the bright surface of the oxidized copper foil with an electrolyte for nickel plating (nickel sulfamate 470 g/L; boric acid 40 g/L). The condition is that the current density per unit area of the copper foil at 50 degrees is 0.5A/dm ² × 30 seconds (=15C/dm ² ).

(4) Heating and pressing of resin base material: each copper foil laminate MEGTRON 6 (prepreg R5670KJ, manufactured by Panasonic Corporation, permittivity 3.71 (1GHz), thickness 100μm) of each copper foil laminate of Example 1 and Comparative Example 1 was pressed by vacuum high pressure The machine was heated and pressed under the conditions of a pressing pressure of 2.9 MPa, a temperature of 210°C, and a pressing time of 120 minutes to obtain a laminate. For each copper-foil laminated PTFE substrate of Example 2 and Comparative Example 2 (NX9255, manufactured by Park Electrochemical, permittivity 2.55 (10 GHz), thickness 0.762 mm), a vacuum high-pressure press was used to apply pressure at 1.5 MPa and temperature Heating and pressing were performed under the conditions of 385°C and a pressing time of 10 minutes to obtain a laminate. Several test pieces were produced under the same conditions for the Examples and Comparative Examples.

＜2. SEM image analysis of cross section＞ 1. Method: The cross section of the obtained laminate (Examples 1 and 2 and Comparative Examples 1 and 2) was obtained by FIB (focused ion beam) processing under the conditions of an acceleration voltage of 30 kV and a probe current of 4 nA. A focused ion beam scanning electron microscope (Auriga, manufactured by Carl Zeiss) was used to observe the obtained cross section at a magnification of 30,000 times and a resolution of 1024×768 to obtain an SEM cross-sectional image. The obtained SEM cross-sectional image is shown in Figure 1. Based on this cross-sectional image, the value of the fractal dimension, the height of the convex part, and the radius of the inscribed circle at the tip of the convex part are measured. The height measurement of the convex part and the measurement of the radius of the inscribed circle at the tip of the convex part are performed using the image analysis software WinROOF2018 (Mitani Corporation, Ver4.5.5). An example of measuring the radius of the inscribed circle at the tip of the convex portion is shown in Figure 2B.

2. Results: The results are shown in Tables 1 to 3 below. Table 1 Example 1 Comparative example 1 Example 2 Comparative example 2 Resin substrate R5670KJ PTFE Fractal dimension 1.403 1.231 1.390 1.192 Table 2 Example 1 Comparative example 1 Example 2 Comparative example 2 Resin substrate R5670KJ PTFE Total number of protrusions 63 48 43 12 height 50nm≦ 47 twenty four 37 12 100nm≦ 14 2 14 5 150nm≦ 3 0 3 1 Table 3 Example 1 Comparative example 1 Example 2 Comparative example 2 Resin substrate R5670KJ PTFE Total number of protrusions 63 48 43 12 Inscribed circle radius ＜25nm 63 48 41 4 ＜20nm 63 46 37 1 ＜15nm 62 43 26 0 ＜10nm 57 twenty one 4 0 ＜5nm 5 0 3 0

<3. Measurement of peel strength> 1. Method: For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, the peel strength was measured in accordance with a 90° peel test (Japanese Industrial Standards (JIS) C5016).

2. Results: The results are shown in Table 4. The peel strength of the comparative example is lower than that of the example, and the failure mode is also interfacial peeling or part of the interface peeling. In contrast, the example is resin aggregation failure. In this way, the laminate of the present invention is superior in peel strength compared with the comparative example. Table 4 Example 1 Comparative example 1 Example 2 Comparative example 2 Resin substrate R5670KJ PTFE Peel strength kgf/cm 0.36 0.19 0.77 0.33 Destruction mode Resin aggregation failure Interface peeling Resin aggregation failure Part of the interface peeled off

＜4. Measurement of heat resistance＞ 1. Method: For the laminates of Example 1 and Comparative Example 1, the peel strength before and after the heat resistance test was measured. The heat resistance test is performed after baking at 125°C for 4 hours, and then performing float soldering (float) for 10 seconds in a solder bath at 288°C (according to IPC TM-650 2.4.8). The difference between the peel strength before and after the heat resistance test is divided by the peel strength before the heat resistance test to calculate the ratio.

2. Results: The results are shown in Table 5 and Figure 3. When comparing the peel strength after the normal state and the heat resistance test, a 53% degradation occurred in Comparative Example 1, but only 19% degradation occurred in Example 1 (Table 5). In addition, after the heat resistance test, discoloration of the copper member was confirmed in the comparative example (emphasized by a frame line in the third figure). This is because the unevenness on the surface of the copper component has been dissolved by the heat resistance test. In this way, the laminate of the present invention is superior in peel strength and heat resistance compared with the comparative example. Table 5 Example 1 Comparative example 1 Resin substrate R5670KJ Peel strength (normal state) kgf/cm 0.36 0.19 Peel strength (after heat resistance test) kgf/cm 0.30 0.09 Deterioration rate % 19 53 Failure mode (after heat resistance test) Resin aggregation failure Interface peeling

＜5. High frequency characteristic＞ 1. Method: For copper foil FV-WS (manufactured by Furukawa Electric Co., Ltd., thickness 18μm, Rz 1.2μm) by thermocompression forming the laminated MEGTRON 6 (prepreg R5670KJ, manufactured by Panasonic, thickness 100μm) As Example 1 and Comparative Example 3, samples for evaluation of transmission characteristics were prepared and the transmission loss in the high frequency band was measured. The evaluation of transmission characteristics is measured using a conventional stripline resonator method suitable for measurement in the 0-50GHz frequency band. Specifically, the S21 parameter was measured in a state without a coverlay film under the following conditions. Measurement conditions: microstrip line structure; base material MEGTRON 6; circuit length: 150mm; conductor width 250μm; conductor thickness 18μm; base material thickness 100μm; characteristic impedance 50Ω.

2. Results: The copper foil FV-WS used in Comparative Example 3 is of low thickness, and it is used for high-frequency substrates that require low transmission loss and are oriented to substrates for high-end routers, servers and other information and communication equipment or antennas for communication base stations. Copper foil, but the transmission loss of Example 1 is smaller than that of Comparative Example 3. In this way, the laminate of the present invention has excellent high-frequency characteristics.

Industrial Applicability: According to the present invention, a novel laminate of a copper member and a resin substrate can be provided.

[Figure 1] SEM cross-sectional analysis image (fractal dimension) of an embodiment of the present invention. [Figure 2A] In the present invention, a schematic diagram illustrating the shape of the convex portion. [Figure 2B] The SEM cross-sectional analysis image of an embodiment of the present invention shows the shape of the convex portion of the layered surface. [Figure 3] The appearance of the test piece after the peel test in an embodiment of the present invention. [Figure 4] Transmission loss measurement result of an embodiment of the present invention.

Claims (12)

A laminate in which at least a part of the surface of a copper member having a plurality of fine protrusions is laminated with a resin base material having a permittivity of 3.8 or less, and the copper member and the resin base material are laminated on the surface The dimension is above 1.25. For example, the layered body of claim 1, wherein the fractal dimension of the layered layer is larger than 1.4. The laminate of claim 1 or 2, wherein at least a part of the surface of the copper member includes a copper oxide layer. The laminate of claim 1 or 2, wherein at least a part of the surface of the copper member is formed of a metal layer other than copper, and the metal other than copper is selected from tin, silver, zinc, aluminum, titanium, bismuth, At least one metal in the group consisting of chromium, iron, cobalt, nickel, palladium, gold and platinum. The laminate of claim 4, wherein the average thickness in the vertical direction of the metal layer other than copper is 10 nm or more and 150 nm or less. The laminate according to any one of claims 1 to 5, wherein the average height of the convex portion in the vertical cross section of the laminate is 50 nm or more and 500 nm or less. The laminate according to claim 6, wherein the vertical cross section of the laminate has an average of 30 or more convex portions per section width of 3.78 μm. The laminate according to any one of claims 1 to 7, wherein the resin substrate contains polyphenylene ether, polytetrafluoroethylene, or a liquid crystal polymer containing p-hydroxybenzoic acid. The laminate according to claim 8, wherein when the resin base material and the copper member are peeled off, the peeling mode is cohesive failure. Such as the laminate of claim 9, wherein the deterioration rate in the heat resistance test is 50% or less. The laminated body according to any one of claims 1 to 10, wherein the laminated body is used for a high-band circuit above 1 GHz. An electronic component manufactured using the laminate of any one of claims 1 to 11.

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