Method for manufacturing laminates

Abstract

The purpose of this invention is to provide a novel method for manufacturing a multilayer, the method comprising: bonding an insulating substrate layer to a copper component having protrusions on its surface; transferring the protrusions to the surface of the insulating substrate layer by peeling off the copper component to form a seed layer; forming photoresist at a predetermined position on the surface of the seed layer; depositing copper by performing copper plating on areas of the seed layer where the photoresist is not deposited; removing the photoresist; and removing the seed layer exposed by removing the photoresist.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a laminate. [Previous Technology]

[0002] In recent years, the demand for miniaturized wiring has gradually increased. Previous wiring methods using copper foil insulating resin and non-removable portions through etching (Japanese Patent Application Laid-Open Nos. 2005-223226, 2010-267891, and 2002-176242) cannot meet the requirements for miniaturization. Therefore, wiring technologies such as the semi-additive process (SAP) or modified semi-additive process (MSAP) are used. Compared to the subtractive process, the MSAP method results in a thinner copper film etched, thus achieving miniaturized wiring.

[0003] In the SAP method, a copper seed layer is generally formed on a resin substrate. To achieve adhesion between the resin substrate and the seed layer, the surface of the insulating resin layer is roughened by desmearing treatment using methods such as permanganate. At this time, the surface roughness (Ra) of the roughened surface of the insulating resin layer is 300 nm or more. Next, a copper seed layer is formed on the insulating resin layer by electroless plating. Then, photoresist is formed on the portion of the seed layer where no wiring layer is formed. Furthermore, a thick copper plating layer is formed on the portion where no photoresist is formed by electroplating. Finally, after removing the photoresist, the exposed seed layer is etched. In this way, a wiring pattern consisting of the seed layer and the metal plating layer is formed on the resin substrate (see Figure 1A). [Summary of the Invention]

[0004] The purpose of this invention is to provide a novel method for manufacturing laminates.

[0005] One embodiment of the present invention is a method for manufacturing a laminate of an insulating substrate layer and copper, comprising: a step of bonding the insulating substrate layer to a copper component having protrusions on its surface; a step of transferring the protrusions to the surface of the insulating substrate layer by peeling off the copper component to form a seed layer; a step of forming photoresist at a predetermined position on the surface of the seed layer; a step of depositing copper by performing copper plating on the surface of the seed layer in areas where the photoresist is not deposited; a step of removing the photoresist; and a step of removing the seed layer exposed by removing the photoresist. The protrusions on the surface of the copper component can be formed on the surface of the copper component by chemical treatment. The protrusions may not be formed on the surface of the insulating substrate layer during desmearing. The copper plating treatment can be copper electroplating. Between the step of forming the seed layer and the step of forming the photoresist, an electroless plating treatment can be performed on the surface of the seed layer. The insulating substrate layer and the copper component can be bonded by hot pressing. When analyzing the surface of the copper component peeled from the insulating substrate layer using attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR / ATR), the S / N ratio of the detected peaks corresponding to the substances from the resin substrate in the wavelength range of 700–4000 cm⁻¹ can be less than 10 or less than 7. When performing spectral analysis on the surface of the resin substrate from which the copper component has been peeled, using X-ray photoelectron spectroscopy (XPS), metal atoms contained in the copper component can be detected on the surface of the resin substrate from which the copper component has been peeled. The total intensity of the main peaks of the metal elements detected on the surface of the resin substrate from which the copper component has been peeled can be greater than the peak intensity of C1s. The ratio of the total percentage of surface atomic composition (Atom%) of metal elements to the percentage of surface atomic composition (Atom%) of C1s calculated by X-ray photoelectron spectroscopy can be greater than 0.03 or greater or greater than 0.04. When the surface of the resin substrate from which the copper component has been peeled is measured and analyzed by X-ray photoelectron spectroscopy, the combined percentage of surface atomic composition of Cu2p3 and Ni2p3 can be 3.0 atom% or more or 1.5 atom% or more. When the surface of the resin substrate from which the copper component has been peeled is measured and analyzed by X-ray photoelectron spectroscopy, the percentage of surface atomic composition of Cu2p3 can be 2.8 atom% or more or 1.0 atom% or more. The copper component with protrusions on the surface can be formed by: 1) partially coating the surface of the copper component as a material with a silane coupling agent or a corrosion inhibitor; and 2) oxidizing the partially coated surface to form a layer containing copper oxide. The copper component with protrusions on the surface can be formed by: 1) oxidizing the surface of the copper component as a material to form a layer containing copper oxide; and 2) treating the oxidized surface with a solvent that dissolves the copper oxide.The solvent may be selected from the group consisting of potassium chloride, nickel chloride, zinc chloride, ferric chloride, chromium chloride, ammonium citrate, ammonium chloride, ammonium sulfate, nickel ammonium sulfate, ethylenediaminetetraacetic acid, dihydroxyethylglycine, tetrasodium L-glutamic acid diacetate, ethylenediamine-N,N'-disuccinic acid, sodium 3-hydroxy-2,2'-iminodisuccinate, trisodium methylglycine diacetate, tetrasodium aspartate diacetate, disodium N-(2-hydroxyethyl)iminodisuccinate, and sodium gluconate.

[0006] Cross-reference with related documents: This application claims priority based on Japanese Patent Application No. 2021-052381 filed on March 25, 2021, and is included in this specification by reference to that basic application.

Implementation Method

[0008] The preferred embodiments of the present invention are described in detail below using accompanying drawings, but the present invention is not limited thereto. Furthermore, based on the description in this specification, those skilled in the art will understand the purpose, features, advantages, and concept of the present invention, and can easily reproduce the present invention based on the description in this specification. The embodiments and specific examples described below are preferred embodiments of the present invention, used for illustration and explanation, and are not intended to limit the present invention. Those skilled in the art will understand that various changes and modifications can be made based on the description in this specification within the intent and scope of the present invention disclosed herein.

[0009] <Method for Manufacturing a Laminated Body> One embodiment of the present invention is a method for manufacturing a laminate of an insulating substrate layer and copper. The manufacturing method includes the steps of bonding an insulating substrate layer to a copper component having protrusions on its surface; transferring the protrusions to the surface of the insulating substrate layer by peeling off the copper component to form a seed layer; forming photoresist at a predetermined position on the surface of the seed layer; depositing copper by performing copper plating on areas of the seed layer where the photoresist is not deposited; removing the photoresist; and removing the seed layer exposed by removing the photoresist. Furthermore, in this specification, the seed layer refers to a layer formed between the surface of the peeled copper component and the surface containing the bottom of a recess formed by the protrusions of the copper component in the insulating substrate layer (Figure 1B). Therefore, the recess and the metal transferred from the copper component to the recess are contained in this layer. The bottom of the recess refers to the bottom of the recess that is furthest from the surface of the copper component being peeled off. The surface system formed by including the bottom of the recess is parallel to the surface of the copper component being peeled off.

[0010] [1]Step of bonding insulating substrate layer and copper <copper component> The surface of the copper component has fine protrusions. The arithmetic mean roughness (Ra) of the surface of the copper component is preferably 0.03 μm or more, more preferably 0.05 μm or more, and more preferably 0.3 μm or less, more preferably 0.2 μm or less.

[0011] The maximum height roughness (Rz) of the surface of the copper component is preferably 0.2 μm or more, more preferably 1.0 μm or more, and even more preferably 2.0 μm or less, and more preferably 1.7 μm or less.

[0012] If Ra and Rz are too small, the adhesion to the resin substrate will be insufficient; if they are too large, the micro-wire formation or high-frequency characteristics will be poor.

[0013] Here, the arithmetic mean roughness (Ra) represents the average of the absolute values ​​of Z(x) (i.e., peak height and valley depth) in the profile curve (y=Z(x)) within the reference length l, expressed by the following formula: Formula 1:

[0014] Maximum height roughness (Rz) represents the sum of the maximum value of the peak height Zp and the maximum value of the valley depth Zv of the profile curve (y=Z(x)) in the reference length l.

[0015] Ra and Rz can be calculated according to the method specified in JIS B 0601:2001 (based on the international standard ISO4287-1997).

[0016] The average length (RSm) of the surface roughness curve parameters of the copper component is not particularly limited, but is preferably 1500 nm or less, 1400 nm or less, 1300 nm or less, 1200 nm or less, 1100 nm or less, 1000 nm or less, 900 nm or less, 800 nm or less, 750 nm or less, 700 nm or less, 650 nm or less, 600 nm or less, 550 nm or less, 450 nm or less, or 350 nm or less, and is preferably 100 nm or more, 200 nm or more, or 300 nm or more. Here, RSm represents the average length of the convexity and concavity generated by one period of roughness curves contained in a reference length (lr) (i.e., the length of the profile curve parameters: Xs1 to Xsm), calculated by the following formula: Formula 2:

[0017] Here, 10% of the arithmetic mean roughness (Ra) is used as the minimum height of the unevenness, and 1% of the reference length (lr) is used as the minimum length to define an unevenness of one period. For example, RSm can be measured and calculated according to "Method for measuring the surface roughness of precision ceramic thin films using atomic force microscopy (JIS R 1683:2007)".

[0018] The copper component is preferably a composite copper component in which at least a portion of its surface is formed with a layer containing copper oxide. Specifically, the copper component includes, but is not limited to, copper foils such as electrolytic copper foil, rolled copper foil, and carrier copper foil, copper wire, copper plate, and copper lead frame. The copper component comprises copper as a main component forming part of its structure. The copper component is preferably made of pure copper with a purity of 99.9% by mass or higher, more preferably of ductile copper, deoxidized copper, or oxygen-free copper, and even more preferably of oxygen-free copper with an oxygen content of 0.001% to 0.0005% by mass.

[0019] When the copper component is copper foil, its thickness is not particularly limited, but it is preferably 0.1 μm or more and 100 μm or less, and more preferably 0.5 μm or more and 50 μm or less.

[0020] <Method for manufacturing copper components> A layer comprising copper oxide is formed on the surface of a copper component, and comprising copper oxide (CuO) and / or cuprous oxide (Cu2O). This layer comprising copper oxide can be formed by oxidizing the surface of the copper component. By this oxidation treatment, the surface of the copper component is roughened.

[0021] This oxidation step does not require a roughening treatment step such as soft etching or etching, but it can still be performed. Furthermore, degreasing, acid cleaning to homogenize the surface by removing the natural oxide film, or alkaline treatment after acid cleaning can also be performed before oxidation to prevent acid from being carried into the oxidation step. The method of alkaline treatment is not particularly limited, but a 0.1–10 g / L alkaline aqueous solution is preferred, and a 1–2 g / L alkaline aqueous solution is even more preferred. An alkaline aqueous solution, such as sodium hydroxide solution, can be used, and treatment at 30–50 °C for 0.5–2 minutes is sufficient.

[0022] The oxidizing agent is not particularly limited; for example, aqueous solutions of sodium chlorite, sodium hypochlorite, potassium chlorate, and potassium perchlorate can be used. Various additives (such as phosphates like trisodium phosphate dodecahydrate) or surface-active molecules can be added to the oxidizing agent. Examples of surface-active molecules include violetin, violetin macrocycles, expanded violetin, condensed violetin, violetin linear polymers, violetin sandwich coordination complexes, violetin arrays, silanes, tetraorgano-silanes, aminoethyl-aminopropyl-trimethoxysilane, (3-aminopropyl)trimethoxysilane, (1-[3-(trimethoxysilyl)propyl]urea) (l-[3-(Trimethoxysilyl)propyl]urea), (3-aminopropyl)triethoxysilane, and (3-epoxypropyloxypropyl) Trimethoxysilane, (3-chloropropyl)trimethoxysilane, (3-epoxypropyloxypropyl)trimethoxysilane, dimethyldichlorosilane, 3-(trimethoxysilyl)propyl methacrylate, ethyltriethoxysilane, triethoxy(isobutyl)silane, triethoxy(octyl)silane, tris(2-methoxyethoxy)(vinyl)silane, trichlorotrimethylsilane, methyltrichlorosilane, silica tetrachloride, tetraethoxysilane, phenyltrimethoxysilane, trichlorotriethoxysilane, vinyl-trimethoxysilane, amines, sugars, etc. The oxidation reaction conditions are not particularly limited, but the preferred temperature of the oxidizing solution is 40–95 °C, more preferably 45–80 °C. The preferred reaction time is 0.5–30 minutes, more preferably 1–10 minutes.

[0023] For layers containing copper oxides, a solvent can be used to adjust the protrusions on the surface of the oxidized copper component. The solvent used in this dissolution step is not particularly limited, but a chelating agent is preferred, especially a biodegradable chelating agent, such as ethylenediaminetetraacetic acid, dihydroxyethylglycine, tetrasodium L-glutamate diacetate, ethylenediamine-N,N'-disuccinic acid, sodium 3-hydroxy-2,2'-iminodisuccinate, trisodium methylglycine diacetate, tetrasodium aspartate diacetate, disodium N-(2-hydroxyethyl)iminodisuccinate, sodium gluconate, etc. The pH value of the dissolving solution is not particularly limited, but alkaline is preferred, more preferably pH 8–10.5, even more preferably pH 9.0–10.5, and even more preferably pH 9.8–10.2.

[0024] Furthermore, the surface of this copper oxide layer can be reduced by a reducing agent, in which case cuprous oxide can be formed on the surface of the copper oxide layer. Examples of reducing agents used in this reduction step include dimethylamine borane (DMAB), diborane, sodium borohydride, and hydrazine.

[0025] The resistivity of pure copper is 1.7×10-8 (Ωm), while that of copper oxide is 1 to 10 (Ωm) and that of cuprous oxide is 1×106 to 1×107 (Ωm). Therefore, the conductivity of the copper oxide layer is low. Even if a large amount of copper oxide layer is transferred to the resin substrate, it is difficult to generate transmission loss due to skin effect when the copper component of the present invention is used to form a circuit of printed wiring board or semiconductor packaging substrate.

[0026] The layer containing copper oxide may contain metals other than copper. The metals contained are not particularly limited, and may include 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, to impart acid resistance and heat resistance, it is preferable to include metals with higher acid resistance and heat resistance than copper, such as nickel, palladium, gold, and platinum.

[0027] A layer containing a metal other than copper may be formed on the copper oxide layer. This layer may be formed on the outermost surface of the copper component by plating. The plating method is not particularly limited, and metals other than copper may be used, such as tin, silver, zinc, aluminum, titanium, bismuth, chromium, iron, cobalt, nickel, palladium, gold, platinum, or various alloys, by electroplating, electroless plating, vacuum evaporation, chemical formation treatment, etc. It is preferable to form a uniform thin plating layer, so electroplating is preferred.

[0028] In the case of electroplating, nickel plating and nickel alloy plating are preferred. Examples of metals formed by nickel plating and nickel alloy plating include pure nickel, nickel-copper alloy, nickel-chromium alloy, nickel-cobalt alloy, nickel-zinc alloy, nickel-manganese alloy, nickel-lead alloy, and nickel-phosphorus alloy.

[0029] Examples of metal salts used for plating include nickel sulfate, nickel sulfamate, nickel chloride, nickel bromide, zinc oxide, zinc chloride, diamine dichloropalladium, ferric sulfate, ferric chloride, anhydrous chromic acid, chromium chloride, sodium chromium sulfate, copper sulfate, copper pyrophosphate, cobalt sulfate, and manganese sulfate.

[0030] In nickel plating, the bath composition preferably includes, for example, nickel sulfate (more than 100 g / L and less than 350 g / L), nickel aminosulfonate (more than 100 g / L and less than 600 g / L), nickel chloride (more than 0 g / L and less than 300 g / L) and mixtures thereof, and may also include sodium citrate (more than 0 g / L and less than 100 g / L) or boric acid (more than 0 g / L and less than 60 g / L) as additives.

[0031] When electroplating is applied to the surface of an oxidized copper foil, the copper oxide on the surface is first reduced to form cuprous oxide or pure copper using charge. Therefore, there is a time delay until the plating is formed, after which the metal layer begins to precipitate. The amount of charge varies depending on the type of plating solution or the amount of copper oxide. For example, when nickel plating is applied to a copper component, in order to form a better thickness, it is preferable to apply a charge of 10 C or more and 90 C or less per dm² area to the electroplated copper component, and more preferably, a charge of 20 C or more and 65 C or less.

[0032] The amount of metal deposited on the outermost surface of the copper component by plating is not particularly limited, but is preferably 0.8 to 6.0 mg / dm2. Furthermore, the amount of metal deposited can be determined by dissolving it in an acidic solution, measuring the metal amount by ICP analysis, and then dividing by the top view area of ​​the structure.

[0033] To facilitate the fracture of the copper oxide layer from the copper component, steps such as 1) partially coating the surface of the copper component with a coating agent such as a silane coupling agent or a corrosion inhibitor before oxidation treatment, and 2) treating the copper oxide layer with a solvent after oxidation treatment, can be performed. By partially coating the surface of the copper component with a coating agent such as a silane coupling agent or a corrosion inhibitor, that part is exempt from oxidation treatment, creating voids in the copper oxide layer, making it easier to fracture from the copper component. Here, the solvent is an agent that dissolves copper oxide. By treating with the solvent, a portion of the copper oxide near the interface between the copper component and the copper oxide layer is dissolved, making it easier for the copper oxide layer to fracture from the copper component.

[0034] The silane coupling agent is not particularly limited and may be selected from silane, tetraorganosilane, aminoethyl-aminopropyl-trimethoxysilane, (3-aminopropyl)trimethoxysilane, (1-[3-(trimethoxysilyl)propyl]urea) (l-[3-(Trimethoxysilyl)propyl]urea), (3-aminopropyl)triethoxysilane, (3-epoxypropyloxypropyl)trimethoxysilane, (3-chloropropyl) Trimethoxysilane, (3-epoxypropyloxypropyl)trimethoxysilane, dimethyldichlorosilane, 3-(trimethoxysilyl)propyl methacrylate, ethyltriethoxysilane, triethoxy(isobutyl)silane, triethoxy(octyl)silane, tris(2-methoxyethoxy)(vinyl)silane, trichlorotrimethylsilane, methyltrichlorosilane, silica tetrachloride, tetraethoxysilane, phenyltrimethoxysilane, trichlorotriethoxysilane, and vinyl-trimethoxysilane.

[0035] The rust inhibitor is not particularly limited and may be selected from 1H-tetrazole, 5-methyl-1H-tetrazole, 5-amino-1H-tetrazole, 5-phenyl-1H-tetrazole, 1,2,3-triazole, 1,2,4-triazole, 1,2,3-benzotriazole, 5-methyl-1H-benzotriazole, 5-amino-1H-benzotriazole, 2-mercaptobenzothiazole, 1,3-dimethyl-5-pyrazolone, pyrrole, 3-methylpyrazol Pyrrole, 2,4-dimethylpyrrole, 2-ethylpyrrole, pyrazole, 3-aminopyrazole, 4-methylpyrazole, 3-amino-5-hydroxypyrazole, thiazole, 2-aminothiazole, 2-methylthiazole, 2-amino-5-methylthiazole, 2-ethylthiazole, benzothiazole, imidazole, 2-methylimidazolium, 2-ethylimidazolium, 2-butylimidazolium, 5-aminoimidazolium, 6-aminoimidazolium, benzimidazole, 2-(methylthio)benzimidazole.

[0036] The treatment with silane coupling agent or corrosion inhibitor can be performed at any time before oxidation treatment. It can be performed together with degreasing treatment, acid cleaning to remove the natural oxide film for uniform treatment, or alkaline treatment after acid cleaning to prevent acid from being carried into the oxidation step. It is preferable to coat a portion (e.g., 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or more but less than 100%) of the surface of the copper component with silane coupling agent or corrosion inhibitor. For this purpose, it is preferable to react at a concentration of 0.1%, 0.5%, 1% or more at room temperature for 30 seconds, 1 minute or more, or 2 minutes or more.

[0037] A solvent used to make a layer containing copper oxide easier to break off from a copper component, which may contain a component that can dissolve copper oxide, and is not limited to nickel chloride, but may also be selected from chlorides (potassium chloride, zinc chloride, ferric chloride, chromium chloride, etc.), ammonium salts (ammonium citrate, ammonium chloride, ammonium sulfate, nickel ammonium sulfate, etc.), chelating agents (ethylenediaminetetraacetic acid, dihydroxyethylglycine, tetrasodium L-glutamic acid diacetate, ethylenediamine-N,N'-disuccinic acid, sodium 3-hydroxy-2,2'-iminodisuccinate, trisodium methylglycine diacetate, tetrasodium aspartate diacetate, disodium N-(2-hydroxyethyl)iminodisuccinate, sodium gluconate, etc.), tin(II) chloride and citric acid.

[0038] In the case of nickel chloride treatment, there are no particular limitations, but it is preferable to immerse the copper component with a copper oxide layer in a nickel chloride solution (concentration 45 g / L or higher) at room temperature or above for 5 seconds or more. Furthermore, treatment with nickel chloride can be performed not only alone, but also simultaneously with oxidation treatment, or simultaneously with plating treatment after oxidation treatment. For example, the plating solution can contain nickel chloride, and the copper component with a copper oxide layer can be immersed in the plating solution for 5 seconds, 10 seconds, 15 seconds, 20 seconds, 30 seconds, 1 minute, or 2 minutes before plating. The immersion time can be appropriately varied according to the oxide film thickness.

[0039] <Insulating Substrate Layer> The substrate of the insulating substrate layer is formed by transferring the surface contour of the uneven copper component to the resin substrate when the surface of the copper component with the uneven shape is attached to the insulating substrate layer. This is not particularly limited, but a resin substrate is preferred. The resin substrate is a material containing resin as the main component. The type of resin is not particularly limited and can be a thermoplastic resin or a thermosetting resin. Preferred resins include polyphenylene oxide (PPE), epoxy resin, polyoxymethylene (PPO), polybenzoxazole (PBO), polytetrafluoroethylene (PTFE), liquid crystal polymer (LCP), thermoplastic polyimide (TPI), fluororesin, polyetherimide, polyetheretherketone, polycyclic olefin, bismaleimide resin, low-capacitance polyimide, cyanate resin, or a mixture thereof. The resin substrate may also contain inorganic fillers or glass fibers. The relative permittivity of the insulating substrate layer used is preferably 5.0 or less, more preferably 4.0 or less, and even more preferably 3.8 or less.

[0040] <Lamination> When bonding the surface of a copper component with irregularities to an insulating substrate layer, the surface contour of the irregular shape of the copper component is transferred to the resin substrate. Therefore, the surface of the insulating substrate layer forms recesses that complement the protrusions on the surface of the copper component, and also forms protrusions that complement the recesses. The bonding method is not particularly limited, but thermal press fitting is preferred. To thermally press the resin substrate onto the surface of the copper component, for example, the resin substrate and the copper component are adhered tightly and laminated, followed by treatment under specified conditions. Specified conditions (such as temperature, pressure, time, etc.) can be those recommended by the respective substrate manufacturer. Specified conditions may include, for example, the following conditions.

[0041] 1) When the resin substrate contains epoxy resin, or is formed of epoxy resin, it is preferable to apply a pressure of 0 to 20 MPa at a temperature of 50 ℃ to 300 ℃ for 1 minute to 5 hours to heat-press the copper component onto the resin substrate.

[0042] For example, 1-1) when the resin substrate is R-1551 (manufactured by Panasonic), it is heated at a pressure of 1 MPa, and after reaching 100 °C, it is maintained at that temperature for 5 to 10 minutes. Then, it is further heated at a pressure of 3.3 MPa, and after reaching 170 to 180 °C, it is maintained at that temperature for 50 minutes to perform hot pressing.

[0043] 1-2) When the resin substrate is R-1410A (manufactured by Panasonic), it is heated at a pressure of 1 MPa to reach 130 ℃ and maintained at that temperature for 10 minutes. Then it is further heated at a pressure of 2.9 MPa to reach 200 ℃ and maintained at that temperature for 70 minutes to perform hot pressing.

[0044] 1-3) When the resin substrate is EM-285 (EMC made), it is heated at a pressure of 0.4 MPa to reach 100 ℃, then the pressure is increased to 2.4~2.9 MPa and further heated to reach 195 ℃. The temperature is maintained at this temperature for 50 minutes to perform hot pressing.

[0045] 1-4) When the resin substrate is GX13 (made by Ajinomoto Fine-Techno), heat is applied while pressing at 1.0 MPa and maintained at 180 °C for 60 minutes to perform hot pressing.

[0046] 2) When the resin substrate contains PPE resin or is formed of PPE resin, it is preferable to apply a pressure of 0 to 20 MPa at a temperature of 50 ℃ to 350 ℃ for 1 minute to 5 hours to heat-press the copper component onto the resin substrate.

[0047] For example, 2-1) when the resin substrate is R5620 (manufactured by Panasonic), after hot pressing at 0.5 MPa to 100 ℃, the temperature and pressure are increased and maintained at 2.0 to 3.0 MPa and 200 to 210 ℃ for 120 minutes for further hot pressing.

[0048] 2-2) When the resin substrate is R5670 (manufactured by Panasonic), after hot pressing at 0.49 MPa to 110 ℃, the temperature and pressure are increased and maintained at 2.94 MPa and 210 ℃ for 120 minutes for further hot pressing.

[0049] 2-3) When the resin substrate is R5680 (manufactured by Panasonic), after hot pressing at 0.5 MPa to 110 ℃, the temperature and pressure are increased and maintained at 3.0~4.0 MPa and 195 ℃ for 75 minutes for further hot pressing.

[0050] 2-4) When the resin substrate is N-22 (made by Nelco), while applying pressure of 1.6 to 2.3 MPa and heating, maintain at 177 °C for 30 minutes, and then further heat at 216 °C for 60 minutes to perform hot pressing.

[0051] 3) When the resin substrate contains PTFE resin or is formed of PTFE resin, it is preferable to apply a pressure of 0 to 20 MPa at a temperature of 50 ℃ to 400 ℃ for 1 minute to 5 hours to heat-press the copper component onto the resin substrate.

[0052] For example, 3-1) when the resin substrate is NX9255 (manufactured by Park Electrochemical), while pressurizing at 0.69 MPa and heating to 260 °C, the pressure is increased to 1.03 to 1.72 MPa and heated to 385 °C, and maintained at 385 °C for 10 minutes to perform hot pressing.

[0053] 3-2) When the resin substrate is RO3003 (made by Rogers), after pressing for 50 minutes (about 220 °C), pressurize to 2.4 MPa and maintain at 371 °C for 30 to 60 minutes to perform hot pressing.

[0054] 4) When the resin substrate comprises liquid crystal polymer (LCP) resin, or is formed of LCP resin, it is preferable to hot-press the copper component to the resin substrate by applying a pressure of 0 to 20 MPa at a temperature of 50°C to 400°C for 1 minute to 5 hours. For example, when the resin substrate is CT-Z (manufactured by Kuraray), it is heated at a pressure of 0 MPa, maintained at 260°C for 15 minutes, and then heated while applying pressure of 4 MPa, maintained at 300°C for 10 minutes to perform hot pressing.

[0055] [2]Step of peeling off the copper component: After the copper component is attached to the insulating substrate layer, the copper component is peeled off from the insulating substrate layer under specified conditions. The protrusions on the surface of the copper component are transferred to the insulating substrate layer, and a seed layer is formed on the surface of the insulating substrate layer. Therefore, the surface of the insulating substrate layer becomes flat.

[0056] The thickness of the seed layer is preferably 2.50 μm or less, more preferably 2.00 μm or less, and even more preferably 1.70 μm or less. It is also preferably 0.01 μm or more, more preferably 0.10 μm or more, and even more preferably 0.36 μm or more. If the thickness is less than 0.01 μm, the plating formation properties are poor, and the adhesion to the insulating substrate is reduced. If the thickness exceeds 2.50 μm, the wiring formation properties deteriorate. Furthermore, the method for measuring the thickness of the seed layer is not particularly limited; for example, the actual thickness of the seed layer can be measured in an SEM image.

[0057] In the method of the present invention, the seed layer system thus produced is used directly as part of the circuit. Since the step of removing the protrusions on the surface of the copper component transferred to the insulating substrate layer is not performed, the adhesion between the copper and the insulating substrate layer is good.

[0058] The conditions for peeling the copper component from the insulating substrate layer are not particularly limited, and can be based on the 90° peel test (Japanese Industrial Standard (JIS) C5016 "Test Method for Flexible Printed Wiring Boards"; corresponding to international standards IEC249-1:1982, IEC326-2:1990). The method for peeling the copper component from the insulating substrate layer is not particularly limited, and can be done mechanically or manually.

[0059] Metals transferred to the surface of the insulating substrate layer after the copper component has been peeled off can be detected using various methods (e.g., X-ray photoelectron spectroscopy (XPS), energy-scattering X-ray spectroscopy (EDS), and inductively coupled plasma emission spectroscopy (ICP-OES / ICP-AES)). For example, metals contained in a copper oxide layer are transferred to the insulating substrate layer after the copper component with a copper oxide layer on its surface has been peeled off.

[0060] XPS is a method of energy analysis that uses X-rays to irradiate an object and captures the photoelectrons (e-) emitted during the ionization of the object. XPS can be used to investigate the types, amounts, and chemical bonding states of elements present on the surface of a sample or up to a specified depth (e.g., up to 6 nm). The analytical point aperture (i.e., the diameter of the cross-section when the analyzable cylindrical portion is cut to form a circle) is suitable for a range of 1 μm to 1 mm. Here, by using XPS measurement spectral analysis, the metal atoms contained in the copper oxide layer on the surface of the insulating substrate from which the copper component has been peeled off can be detected.

[0061] Preferably, the metal contained in the recesses of the copper component is transferred to the insulating substrate layer in such a way that it fills 70% or more, 80% or more, 90% or more, 95% or more, 99% or more, or 99.9% or more of the recesses of the surface contour to be transferred. If the metal fills most of the recesses of the insulating substrate layer, when the surface of the insulating substrate layer is measured by XPS, the sum of the peak intensities of the main peak of the metal atom spectrum is preferably greater than the peak intensity of the main peak of the C1s spectrum. The main peak is the peak with the highest intensity among the several peaks of the metal element. For example, the peaks in the 2p3 orbital region of Cu, the 3d5 orbital region of Sn, the 3d5 orbital region of Ag, the 2p3 orbital region of Zn, the 2p orbital region of Al, the 2p3 orbital region of Ti, the 4f7 orbital region of Bi, the 2p3 orbital region of Cr, the 2p3 orbital region of Fe, the 2p3 orbital region of Co, the 2p3 orbital region of Ni, the 3d5 orbital region of Pd, the 4f7 orbital region of Au, and the 4f7 orbital region of Pt are the main peaks. Furthermore, the peak intensity of the spectrum described here refers to the height of the vertical axis of the XPS spectral data.

[0062] The surface of the insulating substrate layer after the copper component has been stripped, as measured by X-ray photoelectron spectroscopy (XPS), preferably has a Cu2p3 content of 1.0 atom% or more, 1.8 atom% or more, 2.8 atom% or more, 3.0 atom% or more, 4.0 atom% or more, 5.0 atom% or more, or 6.0 atom% relative to the overall surface atoms. Alternatively, when measuring the surface of the transferred copper component by XPS, the ratio of the surface atomic composition percentage of Cu2p3 to the surface atomic composition percentage of C1s is preferably 0.010 or more, 0.015 or more, 0.020 or more, 0.025 or more, 0.030 or more, 0.035 or more, 0.040 or more, 0.045 or more, 0.050 or more, or 0.10 or more.

[0063] When the protrusion of the copper component contains metal other than copper, the total percentage of surface atomic composition of metal atoms on the surface of the stripped insulating substrate layer, as measured by X-ray photoelectron spectroscopy (XPS), is preferably 1.0 atom% or more, 1.5 atom% or more, 1.8 atom% or more, 2.8 atom% or more, 3.0 atom% or more, 4.0 atom% or more, 5.0 atom% or more, or 6.0 atom%. Alternatively, the ratio of (total percentage of surface atomic composition of metal atoms on the surface of the stripped insulating substrate layer) to (percentage of surface atomic composition of C1s on the surface of the stripped insulating substrate layer) is preferably 0.010 or more, 0.015 or more, 0.020 or more, 0.025 or more, 0.030 or more, 0.035 or more, 0.040 or more, 0.045 or more, 0.050 or more, or 0.10 or more.

[0064] The amount of substance from the insulating substrate layer detected on the surface of the copper component peeled off from the insulating substrate layer is preferably below the detection limit, or only a small amount is detected. This is because breakage of the insulating substrate layer can be sufficiently suppressed during the peeling of the copper component. The method for detecting the substance from the insulating substrate layer is not particularly limited; any method suitable for the target substance can be used. For example, in the case of organic matter, the peaks from the insulating substrate layer can be detected by attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR) ("Infrared and Raman Spectroscopy: Principles and Spectral Interpretation" by Peter Larkin). The FT-IR method is an infrared spectroscopy method that uses infrared absorption spectra to identify and / or quantify the substance being measured by irradiating it with infrared light. In the wavelength range of 700 to 4000 cm⁻¹, the S / N ratio is preferably 10 or less, 9 or less, more preferably 8 or less, 7 or less, and even more preferably no peaks from the resin substrate are detected.

[0065] For the surface of a copper component having a raised layer, the ratio of Ra after peeling to Ra before bonding is preferably less than 100%, less than 96%, less than 95%, less than 94%, less than 93%, less than 92%, less than 91%, less than 90%, less than 80%, less than 70%, less than 65%, or less than 60%. The smaller this ratio, the more it indicates that the metal forming the raised layer has been transferred to the insulating substrate layer.

[0066] For copper components with a raised layer, the ratio of the surface area after peeling to the surface area before bonding is preferably less than 100%, less than 98%, less than 97%, less than 96%, less than 95%, less than 94%, less than 93%, less than 92%, less than 91%, less than 90%, less than 80%, or less than 75%. The smaller this ratio, the more it indicates that the metal forming the raised layer has been transferred to the insulating substrate layer. The surface area can be measured using a conjugate focal microscope or an atomic force microscope.

[0067] The ΔE*ab of the surface of the copper component before hot pressing and the surface of the copper component after peeling is preferably 13 or more, 15 or more, 20 or more, 25 or more, 30 or more, or 35 or more. The larger this difference is, the more it indicates that the metal forming the protrusion has been transferred to the insulating substrate layer.

[0068] In conventional SAP methods, as described above, the adhesion between the resin substrate and the seed layer is improved by forming unevenness on the resin as an anchor. In this case, relatively large unevenness is formed on the surface to ensure adhesion, but this causes copper to precipitate from the resin surface to deeper layers. Therefore, when the seed layer is removed by etching, trace amounts of copper are easily left behind. This trace amount of residual copper may cause short circuits between wirings, thus requiring deeper etching. Furthermore, the effect of increasing adhesion through unevenness forming and electroless copper plating is limited to resin substrates with high selectivity; only a portion of resin substrates, such as ABF (Ajinomoto Build-Up Film), can achieve sufficient adhesion.

[0069] Conventional MSAP methods use extremely thin copper foil with a carrier. However, from an operability perspective, the thickness of the extremely thin copper foil layer needs to be at least 1.5 μm, and it needs to undergo a roughening treatment of at least 1 μm. By forming this roughened seed layer on the resin, the adhesion between the resin substrate and the seed layer is improved. At this time, it is necessary to remove a copper layer several μm thick, including the extremely thin copper foil layer and the roughened portion, so a deeper etching process is required.

[0070] However, in recent years, if a large amount of copper is etched into fine patterns, the patterns will scatter and disappear due to lateral etching. Furthermore, since the wiring layer is formed on the roughened surface of the resin substrate or on a seed layer containing the roughened portion, large unevenness can easily lead to high-frequency signal transmission loss. In addition, the effect of increased adhesion through unevenness forming and electroless copper plating is limited to resin substrates with high selectivity; only a portion of resin substrates, such as ABF (Ajinomoto Build-Up Film), can achieve sufficient adhesion.

[0071] The seed layer obtained by the method of the present invention has a smaller surface roughness compared to the roughening process of the conventional SAP method by desmearing, or the roughening of the extremely thin copper foil of the substrate in the conventional MSAP method. Therefore, it can avoid problems such as copper residue after etching, pattern scattering caused by side etching of fine patterns, and transmission loss of high-frequency signals due to unevenness. Furthermore, although the surface roughness is small, there is a dense and fine unevenness, so the insulating substrate and copper are sufficiently bonded.

[0072] [3] Step of forming photoresist at a specified position on the surface of the seed layer: After stripping the copper component, photoresist is formed at a specified position on the surface of the seed layer. The position where the photoresist is formed is the part of the copper non-deposited layer that will later be used in the circuit.

[0073] The photoresist may include a material that is hardened or dissolved by photosensitive, preferably formed by dry film photoresist (DFR), positive liquid photoresist or negative liquid photoresist, but is not particularly limited.

[0074] The DFR preferably comprises an adhesive polymer that facilitates film formation and monomers (e.g., acrylate or methacrylate monomers) and a photopolymerization initiator that undergo photopolymerization upon UV irradiation. To form the DFR, a dry film with a three-layer structure of a cover film / photoresist / carrier film is preferably used. By peeling off the cover film while hot-pressing and laminating the photoresist onto the structure, and then peeling off the carrier film after lamination, a photoresist layer, i.e., the DFR, can be formed on the structure.

[0075] Examples of liquid photoresist include phenolic resin (Novolak) which is soluble in organic solvents. Regarding liquid photoresist, after coating and drying on the surface of a structure, the photoresist can be dissolved or hardened by irradiation to form a photoresist layer.

[0076] The thickness of the photoresist is not particularly limited, but is preferably 1 μm to 200 μm.

[0077] After forming the seed layer and before forming the photoresist, the surface of the seed layer can be plated to form a second seed layer. The plating method is not particularly limited and can be electroplating or electroless plating. For example, a metal selected from nickel, tin, aluminum, chromium, cobalt, and copper can be used to form the film using a conventional electroless plating method. Here, the second seed layer refers to a thin film of metal formed by the plating process. The thickness of the second seed layer is not particularly limited and can be about 0.02 to 2 μm, preferably less than 2.5 μm when combined with the seed layer on the surface of the insulating substrate layer.

[0078] [4]Copper deposition step: Next, copper plating is performed on the area of ​​the seed layer surface where the photoresist is not deposited, thereby depositing copper. This deposited copper then functions as a circuit. The method of copper plating is not particularly limited, and conventional methods can be used for plating.

[0079] [5]Steps for removing photoresist: The method for removing photoresist is not particularly limited. Common methods can be used, such as using fuming nitric acid or piranha solution, or dry ashing methods such as O2 plasma.

[0080] [6]Steps for removing the seed layer: The method for removing the seed layer is not particularly limited. Common methods can be used, such as quick etching or flash etching using sulfuric acid-hydrogen peroxide etchants.

[0081] (First Embodiment) Manufacturing of Composite Copper Foil: In Examples 1-9 and Comparative Examples 2-3, the bright side (glossy surface, which is flat compared to the opposite side) of copper foil (DR-WS, thickness: 18 μm) manufactured by Furukawa Electric Co., Ltd. was used. In Comparative Example 4, the untreated side of copper foil (FV-WS, thickness: 18 μm) manufactured by Furukawa Electric Co., Ltd. was used as the test piece.

[0082] (1) Pretreatment: First, the copper foil was immersed in the solution described below for 1 minute at 25 °C. That is, in Examples 1 and 2, 10 g / L potassium carbonate was used; 1 vol% KBE-903 (3-aminopropyltriethoxysilane; manufactured by Shin-Etsu Silicone) was used; 10 g / L potassium carbonate was used in Example 3; 0.06 g / L potassium bicarbonate was used; 10 g / L potassium hydroxide was used in Examples 4 to 6; 10 g / L potassium hydroxide was used in Example 7; 5 vol% KBM-603 (N-2-(aminoethyl)-3-aminopropyltrimethoxysilane; manufactured by Shin-Etsu Silicone) was used in Example 8; 1 wt% BTA (benzotriazole) was used; 10 g / L potassium carbonate was used in Comparative Example 2; 10 g / L potassium carbonate was used in Comparative Example 3; 0.06 g / L potassium bicarbonate was used.

[0083] (2) Oxidation treatment: The pretreated copper foil was immersed in an oxidizing agent for oxidation treatment. Examples 1, 2, 7, 8 and Comparative Example 2 used a solution of sodium chlorite 60 g / L; potassium hydroxide 20.6 g / L; potassium carbonate 40.2 g / L as the oxidizing agent. Examples 3-6 used a solution of sodium chlorite 46.3 g / L; potassium hydroxide 12.3 g / L; KBM-403 (3-epoxypropyloxypropyltrimethoxysilane; manufactured by Shin-Etsu Silicon) 2.1 g / L as the oxidizing agent. Comparative Example 3 used a solution of sodium chlorite 60.5 g / L; potassium hydroxide 9.1 g / L; potassium carbonate 3.1 g / L; KBM-403 (3-epoxypropyloxypropyltrimethoxysilane; manufactured by Shin-Etsu Silicon) 2.1 g / L as the oxidizing agent. Examples 1, 2, 7, and 8 were immersed in an oxidant at 73°C for 6 minutes, while Examples 3-6 and Comparative Examples 2 and 3 were immersed in an oxidant at 73°C for 2 minutes.

[0084] (3) Pre-plating treatment: After oxidation treatment, Examples 4-6 used the following solvents for pre-plating treatment. Example 4 used a solution of 47.2 g / L tin(II) dihydrate and 1 mL / L hydrochloric acid, and treated at 45 °C for 10 seconds. Example 5 used a solution of 47.2 g / L ammonium chloride, and treated at 45 °C for 60 seconds. Example 6 used a solution of 6.5 mL / L 50% citric acid, and treated at 45 °C for 60 seconds.

[0085] (4) Electroplating treatment: After oxidation treatment, Examples 2, 3 and Comparative Example 3 were electroplated using a first nickel plating solution (nickel sulfate 255 g / L; nickel chloride 49 g / L; sodium citrate 20 g / L). Examples 4-6 were electroplated using a second nickel plating solution (nickel sulfate 255 g / L; sodium citrate 20 g / L) after pre-plating treatment. Example 3 was immersed in the nickel plating solution for 1 minute before electroplating. Example 2 was electroplated at 50 °C and a current density of 0.5 A / dm2 × 116 seconds (=58 C / dm2 copper foil area). Examples 3-6 and Comparative Example 3 were electroplated at 50 °C and a current density of 0.5 A / dm2 × 45 seconds (=22.5 C / dm2 copper foil area).

[0086] Regarding the embodiments and comparative examples, several test pieces were prepared under the same conditions described above. Table 1 summarizes the above conditions. Table 1 deal with detailed Ingredients or conditions unit Example 1 2 3 4 Preprocessing formula Potassium carbonate g / L 10 10 10 0 Potassium bicarbonate g / L 0 0 0.06 0 potassium hydroxide g / L 0 0 0 10 KBM-603 vol% 0 0 0 0 BTA wt% 0 0 0 0 KBE-903 vol% 1 1 0 0 deal with temperature ℃ 25 25 25 25 time min 1 1 1 1 Oxidation treatment formula Sodium chlorite g / L 60 60 46.3 46.3 potassium hydroxide g / L 20.6 20.6 12.3 12.3 Potassium carbonate g / L 40.2 40.2 0 0 KBM-403 g / L 0 0 2.1 2.1 deal with temperature ℃ 73 73 73 73 time min 6 6 2 2 Pretreatment before plating formula tin(II) chloride dihydrate g / L - - - 47.2 ammonium chloride g / L - - - 0 50% citric acid solution mL / L - - - 0 hydrochloric acid mL / L - - - 1 deal with temperature ℃ - - - 45 time sec - - - 10 Plating formula Nickel sulfate g / L - 255 255 255 Nickel chloride g / L - 49 49 0 Sodium citrate g / L - 20 20 20 deal with detailed Ingredients or conditions unit Example 5 6 7 8 Preprocessing formula Potassium carbonate g / L 0 0 0 0 Potassium bicarbonate g / L 0 0 0 0 potassium hydroxide g / L 10 10 10 10 KBM-603 vol% 0 0 5 0 BTA wt% 0 0 0 1 KBE-903 vol% 0 0 0 0 deal with temperature ℃ 25 25 25 25 time min 1 1 1 1 Oxidation treatment formula Sodium chlorite g / L 46.3 46.3 60 60 potassium hydroxide g / L 12.3 12.3 20.6 20.6 Potassium carbonate g / L 0 0 40.2 40.2 KBM-403 g / L 2.1 2.1 0 0 deal with temperature ℃ 73 73 73 73 time min 2 2 6 6 Pretreatment before plating formula tin(II) chloride dihydrate g / L 0 0 - - ammonium chloride g / L 47.2 0 - - 50% citric acid solution mL / L 0 6.5 - - hydrochloric acid mL / L 0 0 - - deal with temperature ℃ 45 45 - - time sec 60 60 - - Plating formula Nickel sulfate g / L 255 255 - - Nickel chloride g / L 0 0 - - Sodium citrate g / L 20 20 - - deal with detailed Ingredients or conditions unit Comparative example 2 3 4 Preprocessing formula Potassium carbonate g / L 10 10 - Potassium bicarbonate g / L 0 0.06 - potassium hydroxide g / L 0 0 - KBM-603 vol% 0 0 - BTA wt% 0 0 - KBE-903 vol% 0 0 - deal with temperature ℃ 25 25 - time min 1 1 - Oxidation treatment formula Sodium chlorite g / L 60 60.5 - potassium hydroxide g / L 20.6 9.1 - Potassium carbonate g / L 40.2 3.1 - KBM-403 g / L 0 2.1 - deal with temperature ℃ 73 73 - time min 2 2 - Pretreatment before plating formula tin(II) chloride dihydrate g / L - - - ammonium chloride g / L - - - 50% citric acid solution mL / L - - - hydrochloric acid mL / L - - - deal with temperature ℃ - - - time sec - - - Plating formula Nickel sulfate g / L - 255 - Nickel chloride g / L - 49 - Sodium citrate g / L - 20 -

[0087] <2. Pressing and peeling of resin substrate> (1) Method The test pieces of Examples 1 to 8 and Comparative Examples 2 to 4 were tested for peeling of resin substrate using R5670KJ (manufactured by Panasonic), R5680J (manufactured by Panasonic), CT-Z (manufactured by Kuraray), NX9255 (manufactured by Park Electrochemical) and R1551GG (manufactured by Panasonic) as prepregs.

[0088] First, the test piece laminated prepreg was hot-pressed in a vacuum using a vacuum high-pressure press to obtain the laminated sample. Furthermore, when the resin substrate was R5670KJ (manufactured by Panasonic), hot-pressing was performed while heating to 110°C at a pressure of 0.49 MPa, followed by increasing the temperature and pressure, maintaining at 210°C and 2.94 MPa for 120 minutes for hot-pressing. When the resin substrate was R5680J (manufactured by Panasonic), hot-pressing was performed while heating to 110°C at a pressure of 0.5 MPa, followed by increasing the temperature and pressure, maintaining at 195°C and 3.5 MPa for 75 minutes for hot-pressing. When the resin substrate is NX9255 (manufactured by Park Electrochemical), it is heated to 260°C while being pressurized at 0.69 MPa, then the pressure is increased to 1.5 MPa and the temperature is raised to 385°C, and held at 385°C for 10 minutes for hot pressing. When the resin substrate is R-1551GG (manufactured by Panasonic), it is heated to 100°C under a pressure of 1 MPa and held at that temperature for 10 minutes, then further heated to 180°C under a pressure of 3.3 MPa and held at that temperature for 50 minutes for hot pressing. When the resin substrate is CT-Z (manufactured by Kuraray), it is heated to 260°C under a pressure of 0 MPa and held at 15 minutes, then further heated to 300°C while being pressurized at 4 MPa and held at 300°C for 10 minutes for hot pressing. For these laminated samples, the copper components were peeled off from the resin substrate using a 90° peel test (Japanese Industrial Standard (JIS) C5016). The visual observation results are shown in Figure 2-1. Furthermore, for a representative combination, surface photographs of the resin side and copper foil side after peeling are shown in Figure 2-2.

[0089] As can be easily observed from Figures 2-1 and 2-2, the surface of the copper foil in the embodiment was transferred to the resin side, but the surface of the copper foil in the comparative example was not transferred to the resin side. To provide material evidence, the following surface analysis was performed.

[0090] <3. Surface Analysis of the Resin Substrate After Peeling> Elemental analysis was performed on the surface of the resin substrate after peeling. Specifically, the obtained resin substrate was analyzed using a Quantera SXM (manufactured by ULVAC-PHI) under the following conditions. An untreated resin substrate (R5670KJ; MEGTRON6) was used as a negative control for analysis (Comparative Example 1).

[0091] (1)Survey Spectrum Measurement The elements were first detected under the following conditions. X-ray source: monochromatic Al Kα (1486.6eV) X-ray beam diameter: 100 μm (25w 15kV) Pass energy: 280eV, 1eV step point analysis: φ100 μm The results of 8 cumulative measurements are shown in Table 2 and Figures 3-1 to 3-7.

[0092] (2) In the results embodiment, the peak intensity of the Cu2p3 spectrum from the transferred copper atoms is greater than the peak intensity of the C1s spectrum from the resin substrate. In contrast, in the comparative example, the peak of the Cu2p3 spectrum was not detected, or its intensity was less than that of the C1s spectrum. This indicates that in the comparative example, copper atoms were hardly transferred to the resin substrate, or were hardly present in the XPS-detectable surface portion of the resin substrate.

[0093] In Example 1, the composite copper foil was not plated, so only copper atom transfer was detected on the resin substrate side. In Examples 2 and 3, nickel plating was performed, so both copper and nickel atom transfer were detected on the resin side.

[0094] Furthermore, compared to the comparative example, the proportion of C1s in any embodiment is smaller. It is presumably because in these embodiments, the proportion of C1s on the surface is relatively smaller by transferring copper oxide or cuprous oxide. Table 2 unit Example 1 2 3 4 Component ratio C1s atom% 69.3 57.75 57.94 50.46 N1s atom% 3.62 3.76 4.21 0 O1s atom% 20.74 29.35 26.42 34.29 Si2p atom% 0 0 0 0 Cl2p atom% 0 0 0 0.91 Br3p atom% 0 0 0 0 Sn3d5 atom% 0 0 0 4.34 Ni2p atom% 0 4.33 8.41 5.68 Cu2p3 atom% 6.34 4.81 3.03 4.32 (Total metallic elements) / C1s 0.091 0.158 0.197 0.284 unit Example 5 6 7 8 Component ratio C1s atom% 81.19 55.75 67.32 50.68 N1s atom% 1.32 0 4.76 3.9 O1s atom% 14.37 29.03 19.97 28.11 Si2p atom% 0 0 0 0 Cl2p atom% 0.23 2.52 1.73 2.05 Br3p atom% 0 0 0 0 Sn3d5 atom% 0 0 0 0 Ni2p atom% 0.67 4.18 0 0 Cu2p3 atom% 2.22 8.51 6.22 15.27 (Total of metal elements) / C1s 0.036 0.228 0.092 0.301 unit Comparative example 1 2 3 4 Component ratio C1s atom% 81.58 79.89 77.94 81.39 N1s atom% 0 4.64 5.13 3.69 O1s atom% 16.53 15.15 16.74 14.38 Si2p atom% 1.69 0 0 0.42 Cl2p atom% 0 0 0 0 Br3p atom% 0.2 0.32 0.19 0.13 Sn3d5 atom% 0 0 0 0 Ni2p atom% 0 0 0 0 Cu2p3 atom% 0 0 0 0 (Total of metal elements) / C1s 0 0 0 0

[0095] <4. Determination of Ra and Surface Area of ​​Composite Copper Foil Before and After Hot Pressing> (1) Method The surface areas of the composite copper foil test pieces of Examples 1-8 and Comparative Examples 2-4 before and after hot pressing were calculated using an OPTELICS H1200 conjugate scanning electron microscope (Lasertec Corporation). Measurement conditions: conjugate focal mode, scanning area 100 μm × 100 μm, blue light source, cut-off value 1 / 5. Objective lens x100, eyepiece x14, digital zoom x1, Z-spacing set to 10 nm, data from 3 positions were obtained, and the surface area is the average of the 3 positions.

[0096] (2) As shown in Table 3, in the examples, Ra and surface area decreased before hot pressing and after peeling, while in the comparative examples, they increased. This indicates that all or part of the protrusions of the composite copper foil in the examples were transferred to the resin side, while in the comparative examples, only part of the resin was transferred to the composite copper foil. Table 3 unit Example 1 2 3 4 Ra roughness before hot pressing μm 0.18 0.21 0.04 0.06 Coarseness Ra after stripping μm 0.12 0.12 0.03 0.04 Rate of change of thickness (After peeling / Before crimping) % 64.48 59.42 94.29 67.80 Surface area S before crimping μm 2 21453 21578 10897 12185 Surface area S after peeling μm 2 15573 16157 10642 10960 Rate of change of surface area (After peeling / Before crimping) % 72.59 74.88 97.66 89.95 unit Example 5 6 7 8 Ra roughness before hot pressing μm 0.05 0.05 0.23 0.19 Coarseness Ra after stripping μm 0.04 0.04 0.05 0.13 Rate of change of thickness (After peeling / Before crimping) % 95.56 82.61 21.46 68.95 Surface area S before crimping μm 2 11109 11132 23636 21709 Surface area S after peeling μm 2 11062 10855 11421 16718 Rate of change of surface area (After peeling / Before crimping) % 99.58 97.52 48.32 77.01 unit Comparative example 2 3 4 Ra roughness before hot pressing μm 0.03 0.04 0.18 Coarseness Ra after stripping μm 0.19 0.05 0.21 Rate of change of thickness (After peeling / Before crimping) % 584.85 130.56 117.71 Surface area S before crimping μm 2 10809 10915 19033 Surface area S after peeling μm 2 17411 11599 21839 Rate of change of surface area (After peeling / Before crimping) % 161.08 106.27 114.74

[0097] <5. Calculate ΔE*ab of composite copper foil before and after hot pressing and peeling> (1) Method: Determine the color difference (L*, a*, b*) of the copper foil surface of each composite copper foil test piece before and after hot pressing and peeling. Calculate ΔE*ab from the obtained values ​​according to the following formula. ΔE*ab = [(ΔL*)2+ (Δa*)2+ (Δb*)2]1 / 2

[0098] (2) As shown in Table 4, before and after hot pressing, ΔE*ab in the embodiment was 15 or more, while in the comparative example it was less than 15. This is because the metal contained in the copper oxide layer in the embodiment was transferred to the resin substrate, thus increasing the color change of the copper component. In contrast, the copper oxide layer in the comparative example remained on the copper component, thus reducing the color change of the copper component. Therefore, the more metal contained in the copper oxide layer was transferred, the greater the difference. In fact, in the photographs of Figure 2-2, the resin side was more colored in the embodiment after peeling, but the resin side remained almost white in the comparative example. Table 4 Example 1 2 3 4 Before crimping L* 14.03 15.39 9.24 14.24 a* -1.33 0.79 0.25 -0.25 b* 3.11 0.53 1.25 -2.40 After peeling L* 47.18 40.41 41.06 33.88 a* 8.86 9.07 4.94 7.12 b* 15.60 12.05 9.62 4.91 Color change ΔL -33.15 -25.02 -31.82 -19.64 Δa -10.19 -8.28 -4.69 -7.37 Δb -12.69 -11.52 -8.37 -7.31 ΔE*ab 36.90 28.80 33.20 22.21 Example 5 6 7 8 Before crimping L* 10.54 13.78 14.49 12.70 a* 0.38 0.07 2.34 -0.35 b* 0.38 0.58 7.08 -0.56 After peeling L* 37.02 33.18 50.76 39.31 a* 7.72 7.60 12.15 4.45 b* -1.35 0.50 11.79 9.79 Color change ΔL -26.48 -19.40 -36.27 -26.61 Δa -7.34 -7.53 -9.81 -4.80 Δb 1.73 0.08 -4.71 -10.35 ΔE*ab 27.53 20.81 37.87 28.95 Comparative example 2 3 4 Before crimping L* 28.05 8.90 52.79 a* 10.77 0.22 18.44 b* 22.48 1.47 16.57 After peeling L* 37.35 17.12 44.87 a* 11.89 7.53 13.81 b* 16.11 -3.81 12.81 Color change ΔL -9.30 -8.22 7.92 Δa -1.12 -7.31 4.63 Δb 6.37 5.28 3.76 ΔE*ab 11.33 12.20 9.91

[0099] <5. Analysis of the surface of the transferred composite copper foil by attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR / ATR method)> (1) Method R1551GG (epoxy), R5670KJ, R5680J (PPE), NX9255 (PTFE) or CT-Z (LCP) were used as resin substrates for hot pressing. The composite copper foil test pieces after peeling were analyzed by FT-IR / ATR method under the following test conditions. Test conditions: Parkin Elmer Spectrtum100 ATR method crystal: germanium decomposition energy: 4 Number of scans: 4 Pressure (force gauge): 40±5 [N] Spectral display: absorbance

[0100] (2) The S / N (signal / noise) ratio is calculated using the same conditions as when hot-pressing composite copper foil. The resin substrate is heated and pressurized, and then FT-IR is used to measure the resin substrate. An arbitrary wavelength within a 50 cm⁻¹ range is selected where no peak originates from the resin. In this embodiment, 3800–3850 cm⁻¹ is used as the wavelength where no peak originates from the resin. Furthermore, the wavelength within the 700–4000 cm⁻¹ range is identified as the wavelength where the maximum peak is detected. When using R1551GG as the resin substrate, the maximum peak detection wavelength is around 1200 cm⁻¹; when using R5670KJ and R5680J as the resin substrate, the maximum peak detection wavelength is around 1190 cm⁻¹; when using NX9255 as the resin substrate, the maximum peak detection wavelength is around 1232 cm⁻¹; and when using CT-Z as the resin substrate, the maximum peak detection wavelength is around 1741 cm⁻¹ (the arrows in Figures 4-1 to 8 indicate the maximum peak detection wavelength).

[0101] The surface of the transferred copper component was measured by FT-IR. A baseline was drawn connecting the two vertices of the peak at the maximum detection wavelength. The difference between the baseline and the maximum height of the peak was taken as the signal value (S). The difference between the maximum and minimum values ​​of the detected peak in the wavelength range of 3800 to 3850 cm⁻¹ was taken as the noise value (N), and the S / N ratio was calculated.

[0102] (3) Results The results are shown in Figures 4-1 to 8 and Table 5. Table 5 R1551GG Example Comparative example 3 3 N Noise width 0.00068 0.0006 S signal altitude 0.0003 0.0069 S / N ratio 0.4 11.5 R5670KJ Example Comparative example 1 2 3 7 8 2 3 4 N Noise Width 0.0007 0.0004 0.0006 0.0004 0.0004 0.0003 0.0007 0.0011 S signal altitude 0.0049 0.0026 0.0015 0.0002 0.0002 0.0650 0.0076 0.0281 S / N ratio 7 6.5 2.5 0.4 0.4 216.7 10.9 25.5 R5680J Example 4 5 6 N Noise width 0.0005 0.0007 0.0007 S signal altitude 0.0013 0.0010 0.0069 S / N ratio 2.6 1.4 9.8 NX9255 Example Comparative example 3 3 N Noise width 0.000535 0.000535 S signal altitude 0.0052 0.0576 S / N ratio 9.7 107.7 CT-Z Example Comparative example 3 3 N Noise width 0.00035 0.00035 S signal altitude 0.0004 0.0125 S / N ratio 1.1 35.7

[0103] As shown in Table 5, no peaks with an S / N ratio of 10 or more corresponding to the organic matter from the resin were detected on the composite copper foil side in the examples, but peaks with an S / N ratio of 10 or more corresponding to the organic matter from the resin were detected on the composite copper foil side in the comparative examples.

[0104] This is because in the comparative example, the metal on the surface of the composite copper foil hardly transferred. When the composite copper foil was peeled off from the resin substrate, the resin agglomerated and broke down. The broken resin adhered to the surface of the composite copper foil, and thus a peak corresponding to the organic matter from the resin was detected. On the other hand, in the embodiment, the metal on the surface of the composite copper foil transferred to the resin substrate. Therefore, after the composite copper foil was peeled off from the resin substrate, the resin hardly adhered to the composite copper foil, and no peak with an S / N ratio of 10 or more corresponding to the organic matter from the resin was detected.

[0105] In other words, in the comparative example, the strength of the protrusion formed by the copper oxide layer is greater than the strength of the resin substrate, so the metal on the surface of the composite copper foil does not transfer, and the resin agglomerates and breaks down. On the other hand, in the embodiment, the strength of the protrusion formed by the copper oxide layer is less than the strength of the resin substrate, so the metal on the surface of the composite copper foil transfers, and therefore almost no resin adheres.

[0106] (Second Embodiment) The circuit is formed using the composite copper foil of Embodiment 3 of the first embodiment. First, the bright side (glossy side, which is flat compared to the opposite side) of copper foil (DR-WS, thickness: 18 μm) manufactured by Furukawa Electric Co., Ltd. is processed under the following conditions to produce the composite copper foil.

[0107] (1)Pretreatment: Immerse copper foil in a solution of 10 g / L potassium carbonate and 0.06 g / L potassium bicarbonate at 25 °C for 1 minute.

[0108] (2)Oxidation treatment: The pretreated copper foil was immersed in an oxidizing agent for oxidation treatment. A solution of sodium chlorite 46.3 g / L; potassium hydroxide 12.3 g / L; KBM-403 (3-epoxypropyloxypropyltrimethoxysilane; manufactured by Shin-Etsu Silicon Co., Ltd.) 2.1 g / L was used as the oxidizing agent, and the foil was immersed in the solution at 73 °C for 2 minutes.

[0109] (3)Electroplating treatment: After oxidation treatment, electroplating is performed using a nickel plating solution (nickel sulfate 255 g / L; nickel chloride 49 g / L; sodium citrate 20 g / L). The copper foil is immersed in the nickel plating solution for 1 minute before electroplating. Electroplating is performed at 50 °C and a current density of 0.5 A / dm2 × 45 seconds (= 22.5 °C / dm2 copper foil area).

[0110] Next, a copper laminate R-5775 (manufactured by Panasonic) with 18 μm copper foil laminated on both sides of a substrate with a thickness of 0.5 mm was used as the core substrate, and GX13 (manufactured by Ajinomoto Fine-Techno) was used as the resin substrate. The core substrate, resin substrate and composite copper foil were stacked in sequence and vacuum laminated. The laminate was then maintained at 180 °C for 30 minutes to obtain a multilayer substrate.

[0111] Subsequently, the composite copper foil is peeled off by hand, transferring the fine irregularities formed on the composite copper foil to the resin substrate, thereby forming a seed layer on the resin substrate. A commercially available photosensitive dry film is attached to the formed seed layer, exposed through a photomask, and developed with 0.8% sodium bicarbonate, thereby forming a plated photoresist.

[0112] Then, using a commercially available copper plating solution, copper plating was applied at a current density of 1 A / dm2 and 30 °C for 30 minutes to form a copper plating film with a thickness of 15 μm.

[0113] Furthermore, after removing the plated photoresist with 5% potassium hydroxide, the seed layer under the plated photoresist is dissolved and removed by etching with a mixture of sulfuric acid and hydrogen peroxide to obtain a multilayer wiring circuit board (Figure 9). In this way, by bonding a copper component with a protrusion on its surface to an insulating substrate layer and peeling off the copper component, the protrusion is transferred to the surface of the insulating substrate layer to form a seed layer. Through the above steps, a multilayer wiring circuit board can be obtained. [Simplified Explanation of the Diagram]

[0007] [Figure 1A] Figure 1A shows a comparison between the manufacturing method of the laminate in one embodiment of the present invention and the prior art SAP method. [Figure 1B] Figure 1B shows a schematic diagram of the seed layer in one embodiment of the present invention. The gray portion shows the insulating substrate layer, and the black portion shows the portion of the copper component transferred to the insulating substrate layer. When the copper component is peeled off from the insulating substrate layer, (A) shows an example of peeling off the copper component from the surface of the insulating substrate layer, and (B) shows an example of peeling off the copper component from the surface away from the insulating substrate layer, closer to the inside of the copper component than the protrusion of the copper component. The two straight lines correspond to the surface of the peeled copper component and the position of the surface formed by the bottom of the recess of the insulating substrate layer by the protrusion of the copper component, respectively. The portion sandwiched between these two straight lines is the seed layer, and the distance between the two straight lines indicated by the arrow is the thickness of the seed layer. Figures 2-1 and 2-2 show the results of visual observation after peeling off the composite copper foils of Examples 1-8 and Comparative Examples 2-4, which were then pressed onto a resin substrate (○ indicates copper foil surface transfer to the resin side, ╳ indicates non-transfer). Representative photographs of both sides of the surface are also shown. Figures 3-1 to 3-7 show the XPS analysis results of the resin substrates of Examples 1-3 and Comparative Examples 1-4. Figures 4-1 to 4-3 show the results of FT-IR / ATR measurements of the surface of the composite copper foils of Examples 1-3 and Comparative Examples 2-4 after hot-pressing them onto a resin substrate (R5670KJ). Figure 5 shows the results of FT-IR / ATR measurements of the surface of the composite copper foils of Examples 3 and Comparative Examples 3 after hot-pressing them onto a resin substrate (R1551GG). [Figures 6-1 and 6-2] The composite copper foils of Examples 4-8 were hot-pressed onto a resin substrate (R5680J), and the surface was measured by FT-IR / ATR after peeling. [Figure 7] Figure 7 shows the surface of the composite copper foils of Examples 3 and Comparative Example 3 after hot-pressing onto a resin substrate (NX9255), and the surface was measured by FT-IR / ATR after peeling. [Figure 8] Figure 8 shows the surface of the composite copper foils of Examples 3 and Comparative Example 3 after hot-pressing onto a resin substrate (CT-Z), and the surface was measured by FT-IR / ATR after peeling. [Figure 9] Figure 9 shows a multilayer wiring circuit board manufactured as an embodiment of the present invention.

Claims

1. A method for manufacturing an insulating substrate layer and a copper laminate, comprising: a step of bonding the insulating substrate layer to a copper component having protrusions on its surface; a step of transferring the protrusions to the surface of the insulating substrate layer by peeling off the copper component to form a seed layer; a step of forming photoresist at a predetermined position on the surface of the seed layer; a step of depositing copper by performing copper plating on the surface of the seed layer in areas where the photoresist is not deposited; a step of removing the photoresist; and a step of removing the seed layer exposed by removing the photoresist, wherein the insulating substrate layer and the copper component are bonded by hot pressing, wherein the substrate of the insulating substrate layer is a resin substrate, and when the surface of the resin substrate to which the copper component is peeled off is measured by X-ray photoelectron spectroscopy, the combined percentage of surface atomic composition of Cu2p3 and Ni2p3 is 3.0 atom% or more.

2. The manufacturing method as described in claim 1, wherein, The copper component with protrusions on the surface is formed by: 1) partially coating the surface of the copper component as a material with a silane coupling agent or corrosion inhibitor; and 2) oxidizing the partially coated surface to form a layer containing copper oxide.

3. A method for manufacturing a laminate of an insulating substrate layer and copper, comprising: a step of bonding the insulating substrate layer to a copper component having protrusions on its surface; a step of transferring the protrusions to the surface of the insulating substrate layer by peeling off the copper component to form a seed layer; a step of forming photoresist at a predetermined position on the surface of the seed layer; a step of depositing copper by performing copper plating on the surface of the seed layer in areas where the photoresist is not deposited; a step of removing the photoresist; and a step of removing the seed layer exposed by removing the photoresist, wherein the copper component having protrusions on its surface is formed by: 1) partially coating the surface of the copper component as a material with a silane coupling agent or a corrosion inhibitor; and 2) oxidizing the partially coated surface to form a layer containing copper oxide.

4. The manufacturing method as described in claim 1 or 3, wherein, The protrusion on the surface of the copper component is formed on the surface of the copper component by chemical treatment.

5. The manufacturing method as described in claim 1 or 3, wherein, No protrusions are formed on the surface of the insulating substrate layer during the desizing process.

6. The manufacturing method as described in claim 1 or 3, wherein, This copper plating process is a copper electroplating process.

7. The manufacturing method as described in claim 1 or 3, wherein, Between the step of forming the seed layer and the step of forming the photoresist, an electroless plating process is performed on the surface of the seed layer.

8. The manufacturing method as described in claim 3, wherein, The substrate used for the insulating substrate layer is a resin substrate, and the insulating substrate layer is bonded to the copper component by hot pressing.

9. The manufacturing method as described in claim 1 or 8, wherein, When the surface of the copper component peeled off from the insulating substrate layer is analyzed by attenuated total reflectance Fourier transform infrared spectroscopy, the S / N ratio of the detected peak corresponding to the material from the resin substrate in the wavelength range of 700 to 4000 cm⁻¹ is less than 10.

10. The manufacturing method as described in claim 9, wherein, The S / N ratio of this peak is below 7.

11. The manufacturing method as described in claim 1 or 8, wherein, When X-ray photoelectron spectroscopy is used to measure and analyze the surface of the resin substrate from which the copper component has been peeled off, metal atoms contained in the copper component are detected in the obtained X-ray photoelectron spectrum from the surface of the resin substrate from which the copper component has been peeled off.

12. The manufacturing method as described in claim 11, wherein, The combined intensity of the main peaks of the metal elements detected on the surface of the resin substrate from which the copper component was peeled off is greater than the peak intensity of C1s.

13. The manufacturing method as described in claim 11, wherein, The sum of the percentage of surface atomic composition (Atom%) of metallic elements calculated by X-ray photoelectron spectroscopy / the percentage of surface atomic composition (Atom%) of C1s is greater than 0.

03.

14. The manufacturing method as described in claim 11, wherein, The sum of the percentage of surface atomic composition (Atom%) of metallic elements / percentage of surface atomic composition (Atom%) of C1s calculated by X-ray photoelectron spectroscopy is greater than 0.

04.

15. The manufacturing method as described in claim 8, wherein, When the surface of the resin substrate from which the copper component was peeled was measured by X-ray photoelectron spectroscopy, the combined percentage of surface atomic composition of Cu2p3 and Ni2p3 was 3.0 atom% or more.

16. The manufacturing method as described in claim 1 or 8, wherein, When the surface of the resin substrate from which the copper component was peeled was measured by X-ray photoelectron spectroscopy, the combined percentage of surface atomic composition of Cu2p3 and Ni2p3 was 1.5 atom% or more.

17. The manufacturing method as described in claim 1 or 8, wherein, When the surface of the resin substrate from which the copper component was peeled was measured by X-ray photoelectron spectroscopy, the surface atomic composition percentage of Cu2p3 was greater than 2.8 atom%.

18. The manufacturing method as described in claim 1 or 8, wherein, When the surface of the resin substrate from which the copper component was peeled was measured by X-ray photoelectron spectroscopy, the surface atomic composition percentage of Cu2p3 was greater than 1.0 atom%.

19. The manufacturing method as described in claim 1 or 3, wherein, The copper component with protrusions on the surface is formed by: 1) oxidizing the surface of the copper component as a material to form a layer containing copper oxide; and 2) treating the oxidized surface with a solvent that dissolves the copper oxide.

20. The manufacturing method as described in claim 19, wherein, The solvent is selected from the group consisting of potassium chloride, nickel chloride, zinc chloride, ferric chloride, chromium chloride, ammonium citrate, ammonium chloride, ammonium sulfate, nickel ammonium sulfate, ethylenediaminetetraacetic acid, dihydroxyethylglycine, tetrasodium L-glutamic acid diacetate, ethylenediamine-N,N'-disuccinic acid, sodium 3-hydroxy-2,2'-iminodisuccinate, trisodium methylglycine diacetate, tetrasodium aspartate diacetate, disodium N-(2-hydroxyethyl)iminodisuccinate, and sodium gluconate.

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