Manufacturing method of laminates

Abstract

The present invention addresses the purpose of providing a novel method for manufacturing a laminate, and includes: a step for affixing an insulated substrate layer and a copper member having convex parts of the surface thereof to each other; a step for peeling off the copper member and thereby transferring the convex parts to the surface of the insulated substrate layer and forming a seed layer; a step for forming a resist at a prescribed location on the surface of the seed layer; a step for performing a copper plating process on a region on the surface of the seed layer on which the resist is not laminated and thereby laminating the copper; a step for removing the resist; and a step for removing the seed layer exposed due to the removal of the resist.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a laminate. [Background technology]

[0002] In recent years, there has been a growing demand for miniaturization of wiring. Conventional subtractive methods (Japanese Patent Publication No. 2005-223226; Japanese Patent Publication No. 2010-267891; Japanese Patent Publication No. 2002-176242), which use insulating resin with copper foil to etch away unwanted copper, cannot meet these miniaturization requirements. Therefore, wiring technologies such as semi-additive (SAP) and modified semi-additive (MSAP) methods are being used. Compared to the subtractive method, the MSAP method allows for miniaturization of wiring because the copper film thickness etched during the process is thinner.

[0003] In the SAP method, it is common to form a copper seed layer on a resin substrate. To achieve good adhesion between the resin substrate and the seed layer, the surface of the insulating resin layer is roughened by desmearing using methods such as the permanganate method. At this time, the surface roughness (Ra) of the roughened surface of the insulating resin layer becomes 300 nm or more. Next, a copper seed layer is formed on the insulating resin layer by electroless plating or the like. Then, a resist is formed on the areas above the seed layer where the wiring layer is not to be placed. Furthermore, a thick copper plating layer is formed in the areas where the resist has not been formed by electroplating. Finally, after removing the resist, the exposed seed layer is etched. As a result, a wiring pattern consisting of the seed layer and the metal plating layer is formed on the resin substrate (see Figure 1A). [Overview of the project] [Problems that the invention aims to solve]

[0004] The present invention aims to provide a novel method for manufacturing laminates. [Means for solving the problem]

[0005] One embodiment of the present invention is a method for manufacturing a laminate of an insulating substrate layer and copper, comprising the steps of: bonding the insulating substrate layer and a copper member having protrusions on its surface; forming a seed layer by peeling off the copper member to transfer the protrusions to the surface of the insulating substrate layer; forming a resist at a predetermined location on the surface of the seed layer; laminating the copper by copper plating an area on the surface of the seed layer where the resist is not laminated; removing the resist; and removing the seed layer exposed by the removal of the resist. The protrusions on the surface of the copper member may be formed on the surface of the copper member by chemical treatment. Protrusions do not need to be formed on the surface of the insulating substrate layer by desmear treatment. The copper plating treatment may be electrolytic copper plating treatment. Between the step of forming the seed layer and the step of forming the resist, a step of electroless plating treatment may be performed on the surface of the seed layer. The insulating substrate layer and the copper member may be bonded together by thermocompression bonding. When the surface of the copper member peeled off from the insulating substrate layer was analyzed using attenuated total reflectance absorption Fourier transform infrared spectroscopy (FT-IR / ATR method), the wavelength range was 700-4000 cm. -1 In this case, the signal-to-noise ratio of the peaks corresponding to the detected substances derived from the resin substrate may be 10 or less or 7 or less. When a survey spectrum analysis is performed on the surface of the resin substrate from which the copper member has been peeled off by X-ray photoelectron spectroscopy (XPS), metal atoms contained in the copper member may be detected from the surface of the resin substrate from which the copper member has been peeled off in the obtained X-ray photoelectron spectroscopy spectrum. The sum of the intensities of the main peaks of the metal elements detected from the surface of the resin substrate from which the copper member has been peeled off may be greater than the peak intensity of C1s. Calculated from the XPS measurement [Total surface atomic composition percentage of metal elements (Atom%)] / [Surface atomic composition percentage of C1s (Atom%)] The ratio may be 0.03 or higher, or 0.04 or higher. When a Survey spectrum analysis is performed on the surface of the resin substrate from which the copper member has been peeled off by X-ray photoelectron spectroscopy (XPS), the sum of the surface atomic composition percentages of Cu2p3 and Ni2p3 may be 3.0 atom% or higher, or 1.5 atom% or higher. When a Survey spectrum analysis is performed on the surface of the resin substrate from which the copper member has been peeled off by X-ray photoelectron spectroscopy (XPS), the surface atomic composition percentage of Cu2p3 may be 2.8 atom% or higher, or 1.0 atom% or higher. The copper member having protrusions on its surface may be formed by 1) a step of partially coating the surface of the copper member to be used as material with a silane coupling agent or a preservative, and 2) a step of forming a layer containing copper oxide by oxidizing the partially coated surface. The copper member having protrusions on its surface may be formed by 1) oxidizing the surface of a copper member 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 nickel chloride, zinc chloride, iron chloride, chromium chloride, ammonium citrate, ammonium chloride, potassium chloride, ammonium sulfate, nickel ammonium sulfate, ethylenediaminetetraacetic acid, diethanolglycine, 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)iminodiacetate, and sodium gluconate.

[0006] ==Cross-reference with related literature== This application claims priority based on Japanese Patent Application No. 2021-052381, filed on 25 March 2021, and is incorporated herein by reference to said basic application. [Brief explanation of the drawing]

[0007] [Figure 1A]Figure 1A is a schematic diagram showing a method for manufacturing a laminate in one embodiment of the present invention, compared with the conventional SAP method. [Figure 1B] Figure 1B is a schematic diagram of a seed layer in one embodiment of the present invention. The gray area represents the insulating substrate layer, and the black area represents the portion of the copper member transferred to the insulating substrate layer. When the copper member is peeled off the insulating substrate layer, (A) is an example where the copper member is peeled off at the surface of the insulating substrate layer, and (B) is an example where the copper member is peeled off from the surface of the insulating substrate layer, inside the protrusion of the copper member. The two straight lines correspond to the position of a surface configured to include the surface of the peeled copper member and the bottom of the recess formed in the insulating substrate layer by the protrusion of the copper member, respectively. The portion between these two straight lines is the seed layer, and the distance between the two straight lines indicated by the arrows is the thickness of the seed layer. [Figure 2] Figure 2 shows the results of visual observation after the composite copper foils of Examples 1-8 and Comparative Examples 2-4 were pressed onto a resin substrate and then peeled off (indicated by ○ if the copper foil surface had transferred to the resin side, and × if it had not), as well as representative photographs of both surfaces. [Figure 3] Figure 3 shows the results of XPS analysis of the resin substrates of Examples 1-3 and Comparative Examples 1-4. [Figure 4] Figure 4 shows the results of measuring the surface of the composite copper foils of Examples 1-3 and Comparative Examples 2-4 by FT-IR / ATR after they were thermocompressed onto a resin substrate (R5670KJ), peeled off, and then subjected to FT-IR / ATR testing. [Figure 5] Figure 5 shows the results of measuring the surface of the composite copper foils of Example 3 and Comparative Example 3 by FT-IR / ATR after they were heat-pressed onto a resin substrate (R1551GG), peeled off, and then subjected to FT-IR / ATR. [Figure 6] Figure 6 shows the results of measuring the surface of the composite copper foils of Examples 4 to 8 using the FT-IR / ATR method after they were thermocompressed onto a resin substrate (R5680J), peeled off, and then subjected to further measurement. [Figure 7] Figure 7 shows the results of measuring the surface of the composite copper foils of Example 3 and Comparative Example 3 by the FT-IR / ATR method after they were thermocompressed onto a resin substrate (NX9255), peeled off, and then subjected to FT-IR / ATR testing. [Figure 8] Figure 8 shows the results of measuring the surface of the composite copper foils of Example 3 and Comparative Example 3 by the FT-IR / ATR method after thermocompression bonding to a resin substrate (CT-Z) and then peeling them off. [Figure 9] Figure 9 shows a multilayer wiring circuit board manufactured in one embodiment of the present invention.

Mode for Carrying Out the Invention

[0008] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not necessarily limited thereto. The objects, features, advantages, and ideas of the present invention are apparent to those skilled in the art from the description of this specification, and those skilled in the art can easily reproduce the present invention from the description of this specification. The embodiments and specific examples of the invention described below show preferred embodiments of the present invention and are shown for illustration or explanation, and the present invention is not limited thereto. It is apparent to those skilled in the art that various modifications and variations can be made based on the description of this specification within the spirit and scope of the present invention disclosed in this specification.

[0009] <Method for Manufacturing a Laminated Body of an Insulating Substrate Layer and Copper> One embodiment of the disclosure herein is a method for manufacturing a laminate of an insulating substrate layer and copper, comprising the steps of: bonding an insulating substrate layer and a copper member having protrusions on its surface; peeling off the copper member to transfer the protrusions to the surface of the insulating substrate layer and form a seed layer; forming a resist at a predetermined location on the surface of the seed layer; laminating copper by copper plating an area on the surface of the seed layer where the resist is not laminated; removing the resist; and removing the seed layer exposed by removing the resist. In this specification, the seed layer refers to a layer formed between the surface of the peeled copper member and a surface configured to include the bottom of a recess formed in the insulating substrate layer by the protrusions of the copper member (Figure 1B). Therefore, the recess and the metal derived from the copper member transferred to the recess are included in the layer. The bottom of a recess refers to the bottom of a plurality of recesses that is furthest from the surface of the peeled copper member, and the surface configured to include the bottom of the recess is parallel to the surface of the peeled copper member.

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

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

[0012] If Ra and Rz are too small, adhesion to the resin substrate will be insufficient, and if they are too large, the ability to form fine wiring and 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., the height of the convex part and the depth of the concave part) in the contour curve (y=Z(x)) expressed by the following equation, at a reference length l.

number

[0014] Maximum height roughness (Rz) represents the sum of the maximum height Zp of the convex part and the maximum depth Zv of the concave part of the contour curve (y=Z(x)) at a reference length l.

[0015] Ra and Rz can be calculated using the method specified in JIS B 0601:2001 (compliant with the international standard ISO 4287-1997).

[0016] The average length (RSm) of the surface roughness curve elements of the copper member is not particularly limited, but is preferably 1500nm or less, 1400nm or less, 1300nm or less, 1200nm or less, 1100nm or less, 1000nm or less, 900nm or less, 800nm ​​or less, 750nm or less, 700nm or less, 650nm or less, 600nm or less, 550nm or less, 450nm or less, or 350nm or less, and preferably 100nm or more, 200nm or more, or 300nm or more. Here, RSm represents the average length of the surface roughness curve containing one period of irregularities (i.e., the length of the contour curve elements: Xs1~Xsm) at a certain reference length (lr), and is calculated by the following formula.

number

[0017] Here, the minimum height of the surface roughness is defined as 10% of the arithmetic mean roughness (Ra), and the minimum length is defined as 1% of the reference length (lr), thus defining the surface roughness for one period. As an example, RSm can be measured and calculated in accordance with the "Method for Measuring Surface Roughness of Fine Ceramic Thin Films by Atomic Force Microscopy (JIS R 1683:2007)".

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

[0019] When the copper component is copper foil, its thickness is not particularly limited, but 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> The copper oxide layer is formed on the surface of the copper component and contains copper oxide (CuO) and / or cuprous oxide (Cu2O). This copper oxide layer can be formed by oxidizing the surface of the copper component. This oxidation treatment roughens the surface of the copper component.

[0021] Prior to this oxidation step, surface roughening treatments such as soft etching or etching are not necessary but may be performed. Furthermore, prior to the oxidation treatment, degreasing, acid cleaning to homogenize the surface by removing the natural oxide film, or alkaline treatment after acid cleaning to prevent the introduction of acid into the oxidation step may be performed. The method of alkaline treatment is not particularly limited, but preferably, an alkaline aqueous solution of 0.1 to 10 g / L, more preferably 1 to 2 g / L, such as an aqueous sodium hydroxide solution, should be used, and the treatment should be performed at 30 to 50°C for about 0.5 to 2 minutes.

[0022] The oxidizing agent is not particularly limited, and for example, aqueous solutions of sodium chlorite, sodium hypochlorite, potassium chlorate, potassium perchlorate, etc. can be used. Various additives (for example, phosphates such as trisodium phosphate dodecahydrate) and surface-active molecules may be added to the oxidizing agent. Surface-active molecules include porphyrin, macro-ring porphyrin, expanded porphyrin, ring-contracted porphyrin, linear porphyrin polymer, porphyrin sandwich coordination complex, porphyrin sequence, silane, tetraorgano-silane, aminoethyl-aminopropyltrimethoxysilane, (3-aminopropyl)trimethoxysilane, (1-[3-(trimethoxysilyl)propyl]urea)((l-[3-(Trimethoxysilyl)propyl]urea)), (3-aminopropyl)triethoxysilane, ((3-glycidyloxypropyl)trimethoxysilane Examples of oxidizing agents include (3-chloropropyl)trimethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, dimethyldichlorosilane, 3-(trimethoxysilyl)propyl methacrylate, ethyltriacetoxysilane, triethoxy(isobutyl)silane, triethoxy(octyl)silane, tris(2-methoxyethoxy)(vinyl)silane, chlorotrimethylsilane, methyltrichlorosilane, silicon tetrachloride, tetraethoxysilane, phenyltrimethoxysilane, chlorotriethoxysilane, ethylene-trimethoxysilane, amines, sugars, etc. The oxidation reaction conditions are not particularly limited, but the temperature of the oxidizing solution is preferably 40 to 95°C, and more preferably 45 to 80°C. The reaction time is preferably 0.5 to 30 minutes, and more preferably 1 to 10 minutes.

[0023] The copper oxide layer may be prepared by using a solvent to adjust the protrusions on the surface of the oxidized copper component. The solvent used in this dissolution step is not particularly limited, but it is preferably a chelating agent, especially a biodegradable chelating agent, and examples include ethylenediaminetetraacetic acid, diethanolglycine, L-glutamic acid diacetate tetrasodium, ethylenediamine-N,N'-disuccinic acid, 3-hydroxy-2,2'-iminodisuccinate sodium, methylglycine diacetate trisodium, aspartate diacetate tetrasodium, N-(2-hydroxyethyl)iminodiacetate disodium, and sodium gluconate. The pH of the dissolving solution is not particularly limited, but it is preferably alkaline, more preferably pH 8 to 10.5, even more preferably pH 9.0 to 10.5, and even more preferably pH 9.8 to 10.2.

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

[0025] The resistivity of pure copper is 1.7 × 10⁻⁶ -8 While (Ωm) is the density of copper oxide, copper oxide has a density of 1-10 (Ωm). Cuprous oxide is 1 × 10 6 ~1 × 10 7 Because the conductivity is (Ωm), the layer containing copper oxide has low conductivity, and even if a large amount of the layer containing copper oxide transferred to the resin substrate is present, when forming circuits on printed wiring boards or semiconductor package substrates using the copper component according to the present invention, transmission loss due to the skin effect is less likely to occur.

[0026] The copper oxide layer may also contain metals other than copper. The metals included are not particularly limited, but may include at least one metal selected from the group consisting of Sn, Ag, Zn, Al, Ti, Bi, Cr, Fe, Co, Ni, Pd, Au, and Pt. In particular, to have acid resistance and heat resistance, it is preferable to include metals that have higher acid resistance and heat resistance than copper, such as Ni, Pd, Au, and Pt.

[0027] A layer containing a metal other than copper may be formed on top of a layer containing copper oxide. This layer can be formed on the outermost surface of the copper member by plating. The plating method is not particularly limited; for example, Sn, Ag, Zn, Al, Ti, Bi, Cr, Fe, Co, Ni, Pd, Au, Pt, or various alloys can be used as the metal other than copper, and plating can be performed by electroplating, electroless plating, vacuum deposition, chemical conversion treatment, etc. However, electroplating is preferred because it is preferable to form a uniform and thin plating layer.

[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, Ni-Cu alloy, Ni-Cr alloy, Ni-Co alloy, Ni-Zn alloy, Ni-Mn alloy, Ni-Pb alloy, Ni-P alloy, and the like.

[0029] Examples of metal salts used for plating include nickel sulfate, nickel sulfamate, nickel chloride, nickel bromide, zinc oxide, zinc chloride, diamminedichloropalladium, iron sulfate, iron chloride, chromic anhydride, chromium chloride, sodium chromium sulfate, copper sulfate, copper pyrophosphate, cobalt sulfate, and manganese sulfate.

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

[0031] When electroplating is applied to an oxidized copper foil surface, the copper oxide on the surface is first reduced to cuprous oxide or pure copper, using up charge. This creates a time lag before plating occurs, after which the metal that forms the metal layer begins to deposit. The amount of charge varies depending on the type of plating solution and the amount of copper oxide, but for example, when applying Ni plating to a copper component, in order to keep the thickness within a desirable range, the area dm of the copper component to be electroplated is... 2 It is preferable to apply a charge of 10C to 90C per unit, and more preferably a charge of 20C to 65C per unit.

[0032] The amount of metal deposited on the outermost surface of the copper component by plating is not particularly limited, but is generally between 0.8 and 6.0 mg / dm 2 It is preferable that this is the case. The amount of metal deposited can be calculated, for example, by dissolving it in an acidic solution, measuring the amount of metal by ICP analysis, and dividing it by the planar field of view area of ​​the structure.

[0033] To make the layer containing copper oxide more easily detached from the copper member, the following steps may be taken: 1) partially coating the surface of the copper member with a coating agent such as a silane coupling agent or preservative before oxidation treatment, and 2) treating the layer containing copper oxide with a solvent after oxidation treatment. By partially coating the surface of the copper member with a coating agent such as a silane coupling agent or preservative, that portion is spared from oxidation treatment, creating voids in the layer containing copper oxide, which makes it easier for the layer containing copper oxide to detach from the copper member. Here, the solvent is a chemical that dissolves copper oxide, and by treating with the solvent, the copper oxide near the interface between the copper member and the layer containing copper oxide is partially dissolved, making it easier for the layer containing copper oxide to detach from the copper member.

[0034] Silane coupling agents are not particularly limited, but include silane, tetraorgano-silane, aminoethyl-aminopropyltrimethoxysilane, (3-aminopropyl)trimethoxysilane, (1-[3-(trimethoxysilyl)propyl]urea)((l-[3-(Trimethoxysilyl)propyl]urea)), (3-aminopropyl)triethoxysilane, ((3-glycidyloxypropyl)trimethoxysilane), (3-chloropropyl)trimethoxysilane, (3-glycidyl You may choose from oxypropyl)trimethoxysilane, dimethyldichlorosilane, 3-(trimethoxysilyl)propyl methacrylate, ethyltriacetoxysilane, triethoxy(isobutyl)silane, triethoxy(octyl)silane, tris(2-methoxyethoxy)(vinyl)silane, chlorotrimethylsilane, methyltrichlorosilane, silicon tetrachloride, tetraethoxysilane, phenyltrimethoxysilane, chlorotriethoxysilane, and ethylene-trimethoxysilane.

[0035] Rust inhibitors are not particularly limited, but include 1H-tetrazol, 5-methyl-1H-tetrazol, 5-amino-1H-tetrazol, 5-phenyl-1H-tetrazol, 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-pyrazol, pyrrole, 3-methylpyrrole, 2,4-dimethylpyrrole, 2-ethylpyrrole You may choose from 3-aminopyrazole, 3-aminopyrazole, 4-methylpyrazole, 3-amino-5-hydroxypyrazole, thiazole, 2-aminothiazole, 2-methylthiazole, 2-amino-5-methylthiazole, 2-ethylthiazole, benzothiazole, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-butylimidazole, 5-aminoimidazole, 6-aminoimidazole, benzimidazole, and 2-(methylthio)benzoimidazole.

[0036] Treatment with a silane coupling agent or preservative may be performed at any time before the oxidation treatment, and may be carried out in conjunction with degreasing, acid washing to remove the natural oxide film and ensure uniformity, or alkaline treatment after acid washing to prevent the introduction of acid into the oxidation process. Treatment with a silane coupling agent or preservative is preferably used to partially coat the copper member surface (for example, 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% or more, but less than 100%), and for this purpose, it is preferable to react the agent at a concentration of 0.1%, 0.5%, 1%, or 2% or more at room temperature for 30 seconds, 1 minute, or 2 minutes or more.

[0037] The solvent for facilitating the rupture of the copper oxide layer from the copper member can be any solvent that contains a component that dissolves copper oxide, and is not limited to nickel chloride. It may be selected from chlorides (potassium chloride, zinc chloride, iron chloride, chromium chloride, etc.), ammonium salts (ammonium citrate, ammonium chloride, ammonium sulfate, nickel ammonium sulfate, etc.), chelating agents (ethylenediaminetetraacetic acid, diethanolglycine, 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)iminodiacetate, sodium gluconate, etc.), tin(II) chloride, and citric acid.

[0038] When treating with nickel chloride, although not particularly limited, it is preferable to immerse the copper component with a layer containing copper oxide in a nickel chloride solution (concentration of 45 g / L or higher) at room temperature or a temperature higher than room temperature for 5 seconds or more. Furthermore, treatment with nickel chloride may be performed not only alone, but also simultaneously with oxidation treatment, or simultaneously with plating treatment after oxidation treatment. For example, nickel chloride may be included in the plating solution, and the copper component with a layer containing copper oxide may 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 changed depending on the oxide film thickness.

[0039] <Insulating substrate layer> The substrate for the insulating substrate layer is not particularly limited as long as the surface profile, including the uneven shape of the copper member, is transferred to the resin substrate when the surface of the copper member with unevenness is bonded to the insulating substrate layer, but a resin substrate is preferred. The resin substrate is a material that mainly contains resin, but the type of resin is not particularly limited and may be a thermoplastic resin or a thermosetting resin. Examples include polyphenylene ether (PPE), epoxy, polyphenylene oxide (PPO), polybenzoxazole (PBO), polytetrafluoroethylene (PTFE), liquid crystal polymer (LCP), thermoplastic polyimide (TPI), fluororesin, polyetherimide, polyetheretherketone, polycycloolefin, bismaleimide resin, low dielectric constant polyimide, cyanate resin, or a mixture thereof. The resin substrate may further contain inorganic fillers or glass fibers. The relative dielectric constant 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] <Bonding> When the surface of a copper component with irregularities is bonded to an insulating substrate layer, the surface profile, including the irregularities of the copper component, is transferred to the resin substrate. Consequently, the surface of the insulating substrate layer forms recesses that correspond to the protrusions on the copper component surface, and protrusions that correspond to the recesses. The method of bonding is not particularly limited, but thermal press fitting is preferred. To thermal press the resin substrate onto the surface of the copper member, for example, the resin substrate and the copper member can be laminated in close contact, and then heat-treated under predetermined conditions. As predetermined conditions (e.g., temperature, pressure, time, etc.), the recommended conditions of each substrate manufacturer may be used. Examples of predetermined conditions include the following:

[0041] 1) If the resin substrate contains epoxy resin or is made of epoxy resin, it is preferable to heat-press the copper member onto the resin substrate by applying a pressure of 0 to 20 MPa at a temperature of 50°C to 300°C for 1 minute to 5 hours.

[0042] for example, 1-1) If the resin substrate is R-1551 (manufactured by Panasonic), Heat under a pressure of 1 MPa, and once it reaches 100°C, hold it at that temperature for 5-10 minutes; The parts are then heated further under a pressure of 3.3 MPa until they reach 170-180°C, and then held at that temperature for 50 minutes to perform the heat-sealing process.

[0043] 1-2) If the resin substrate is R-1410A (manufactured by Panasonic), The parts are heated under a pressure of 1 MPa, held at 130°C for 10 minutes, and then further heated under a pressure of 2.9 MPa, held at 200°C for 70 minutes to perform the heat sealing process.

[0044] 1-3) If the resin substrate is EM-285 (manufactured by EMC), The material is heated under a pressure of 0.4 MPa, and after reaching 100°C, the pressure is increased to 2.4-2.9 MPa and heating continues until it reaches 195°C, at which point it is held for 50 minutes to perform the heat-sealing process.

[0045] 1-4) If the resin substrate is GX13 (manufactured by Ajinomoto Fine Techno), heat-pressure bonding is performed by heating under pressure of 1.0 MPa and holding at 180°C for 60 minutes.

[0046] 2) If the resin substrate contains or is made of PPE resin, it is preferable to heat-press the copper member onto the resin substrate by applying a pressure of 0 to 20 MPa at a temperature of 50°C to 350°C for 1 minute to 5 hours.

[0047] for example, 2-1) If the resin substrate is R5620 (manufactured by Panasonic), After heat-pressing under a pressure of 0.5 MPa until the temperature reaches 100°C, the temperature and pressure are increased to 2.0-3.0 MPa and 200-210°C, where the bond is maintained for 120 minutes to further heat-press the parts.

[0048] 2-2) If the resin substrate is R5670 (manufactured by Panasonic), After heat-pressing under a pressure of 0.49 MPa while heating to 110°C, the temperature and pressure are increased and the bonding is completed by holding at 2.94 MPa and 210°C for 120 minutes.

[0049] 2-3) If the resin substrate is R5680 (manufactured by Panasonic), heat-seal it while heating it to 110°C under a pressure of 0.5 MPa, then increase the temperature and pressure to 3.0-4.0 MPa and 195°C, and hold for 75 minutes to complete the heat-sealing process.

[0050] 2-4) If the resin substrate is N-22 (manufactured by Nelco), heat it while pressurizing it at 1.6 to 2.3 MPa, hold it at 177°C for 30 minutes, then heat it again and hold it at 216°C for 60 minutes to perform heat bonding.

[0051] 3) If the resin substrate contains or is made of PTFE resin, it is preferable to heat-bond 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.

[0052] for example, 3-1) If the resin substrate is NX9255 (manufactured by Park Electrochemical), heat it to 260°C while pressurizing it at 0.69 MPa, then increase the pressure to 1.03-1.72 MPa and heat it to 385°C, and hold it at 385°C for 10 minutes to perform heat compression bonding.

[0053] 3-2) If the resin substrate is RO3003 (manufactured by Rogers), the heat-pressure bonding is performed by applying pressure to 2.4 MPa after 50 minutes from the start of pressing (approximately 220°C) and holding at 371°C for 30 to 60 minutes.

[0054] 4) If the resin substrate contains or is made of liquid crystal polymer (LCP), it is preferable to heat-bond 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, if the resin substrate is CT-Z (manufactured by Kuraray), the copper component is heat-bonded by heating under a pressure of 0 MPa, holding at 260°C for 15 minutes, then further heating while applying pressure of 4 MPa, and holding at 300°C for 10 minutes.

[0055] [2] Process of peeling off copper components After bonding a copper component to an insulating substrate layer, when the copper component is peeled off the insulating substrate layer under predetermined conditions, the protrusions on the surface of the copper component are transferred to the insulating substrate layer, forming a seed layer on the surface of the insulating substrate layer. Consequently, the surface of the insulating substrate layer becomes flat.

[0056] The thickness of the seed layer may be 2.50 μm or less, more preferably 2.00 μm or less, and even more preferably 1.70 μm or less. Furthermore, it is 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 formability is poor and the adhesion to the insulating substrate decreases. If it exceeds 2.50 μm, the wiring formability deteriorates. The method for measuring the seed layer thickness is not particularly limited; for example, the thickness of the seed layer can be measured in an SEM image.

[0057] In the method disclosed herein, the seed layer thus produced is used as is as part of the circuit. By not going through the process of removing the protrusions on the surface of the copper component that has been transferred to the insulating substrate layer, good adhesion between the copper and the insulating substrate layer is achieved.

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

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

[0060] XPS irradiates an object with X-rays, and photoelectrons e are emitted as the object is ionized. - This technique performs energy analysis by capturing XPS. XPS can be used to investigate the types, abundances, and chemical bonding states of elements present on the sample surface or to a predetermined depth (for example, up to a depth of 6 nm). A suitable analysis spot diameter (i.e., the diameter of the cross-section when the cylindrical portion to be analyzed is cut so that the cross-section is circular) is between 1 μm and 1 mm. Here, it is sufficient for metal atoms contained in the copper oxide layer to be detected from the surface of the insulating substrate from which the copper component has been peeled off, by XPS survey spectrum analysis.

[0061] It is preferable that the metal contained in the protrusions of the copper component is transferred to the insulating substrate layer so as to fill 70% or more, 80% or more, 90% or more, 95% or more, 99% or more, or 99.9% or more of the recesses in the transferred surface profile. When the metal fills most of the recesses in 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 peaks of the metal atoms' spectra becomes greater than the peak intensity of the main peak of the C1s spectrum. The main peak is the peak with the greatest intensity among the multiple peaks of a metal element. For example, the main peaks are the 2p3 orbital for Cu, the 3d5 orbital for Sn, the 3d5 orbital for Ag, the 2p3 orbital for Zn, the 2p3 orbital for Al, the 2p3 orbital for Ti, the 4f7 orbital for Bi, the 2p3 orbital for Cr, the 2p3 orbital for Fe, the 2p3 orbital for Co, the 2p3 orbital for Ni, the 3d5 orbital for Pd, the 4f7 orbital for Au, and the 4f7 orbital for Pt. Note that the peak intensity of the spectrum referred to here means the height along the vertical axis of the XPS spectral data.

[0062] Preferably, the ratio of Cu2p3 to the total atoms on the surface of the insulating substrate layer from which the copper component has been peeled off, as measured by X-ray photoelectron spectroscopy (XPS), is 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%. Alternatively, when the surface of the copper component after transfer is measured 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] If the protrusions of the copper component contain metals other than copper, it is preferable that the total percentage of metal atoms in the atomic composition on the surface of the peeled insulating substrate layer, as measured by X-ray photoelectron spectroscopy (XPS), is 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, it is preferable that the ratio of (total percentage of metal atoms in the atomic composition on the surface of the peeled insulating substrate layer) to (percentage of C1s in the atomic composition on the surface of the peeled insulating substrate layer) is 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 originating from the insulating substrate layer detected on the surface of a copper component peeled from the insulating substrate layer is preferably below the detection limit, or at least in small quantities. This is because the fracture of the insulating substrate layer is sufficiently suppressed when the copper component is peeled off. The method for detecting substance originating from the insulating substrate layer is not particularly limited, and any method suitable for the target substance may be used. For example, in the case of organic substances, this can be done by detecting peaks originating from the insulating substrate layer using attenuated total reflectance absorption Fourier transform infrared spectroscopy (FT-IR method) ("Infrared and Raman Spectroscopy: Principles and Spectral Interpretation" by Peter Larkin). The FT-IR method is an infrared spectroscopy method that irradiates the substance to be measured with infrared light and identifies and / or quantifies compounds using the infrared absorption spectrum, with a wavelength range of 700-4000 cm². -1 In this case, the signal-to-noise ratio is preferably 10 or less, 9 or less, more preferably 8 or less, 7 or less, and it is preferable that no peaks originating from the resin substrate are detected.

[0065] The ratio of Ra after peeling to Ra before bonding of the surface of the copper member having the convex portion formed thereon is 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%. It is preferable that the smaller this ratio is, the more it means that the metal forming the convex portion has transferred to the insulating base material layer.

[0066] The ratio of the surface area after peeling to the surface area before bonding of the copper member having the convex portion formed thereon is 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%. It is preferable that the smaller this ratio is, the more it means that the metal forming the convex portion has transferred to the insulating base material layer. The surface area can be measured using a confocal microscope or an atomic force microscope.

[0067] ΔE * ab of the surface of the copper member before thermocompression bonding and the surface of the copper member 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 means that the metal forming the convex portion has transferred to the insulating base material layer.

[0068] In the conventional SAP method, as described above, by forming irregularities that serve as an anchor in the resin, the adhesion between the resin substrate and the seed layer is enhanced. At that time, relatively large irregularities were formed on the surface to ensure adhesion. However, as a result, copper was deposited deeply from the resin surface layer, so a small amount of copper tended to remain when the seed layer was etched and removed. This remaining small amount of copper can cause a short circuit between wirings, so a deep etching process was required. Furthermore, the effect of increasing the adhesion by the irregularity formation process and the electroless copper plating film is highly resin substrate selective, and a sufficient adhesion effect can be obtained only for some resin substrates such as ABF (Ajinomoto Build-Up Film).

[0069] Conventional MSAP methods use ultrathin copper foil with a carrier, but the thickness of the ultrathin copper foil layer needs to be 1.5 μm or more for handling purposes, and in addition, it is subjected to a roughening treatment of 1 μm or more. By forming this roughened seed layer on the resin, the adhesion between the resin substrate and the seed layer is improved. In this process, it is necessary to remove a copper layer several μm thick that includes the ultrathin copper foil layer and the roughened portion, so a deep etching treatment was required.

[0070] However, with recent fine patterns, etching a large amount of copper can cause pattern skipping due to side etching, resulting in the disappearance of the pattern. Furthermore, since the wiring layer is formed on the roughened surface of the resin substrate or on the seed layer which includes the roughened area, large irregularities can easily lead to transmission loss of high-frequency signals. Moreover, the effect of increasing adhesion by the surface irregularity formation treatment and the electroless copper plating film is highly selective for resin substrates, and sufficient adhesion can only be obtained with certain resin substrates such as ABF (Ajinomoto Build-Up Film).

[0071] The seed layer obtained by the method disclosed herein has a lower surface roughness than that obtained by desmearing in the conventional SAP method or by roughening an ultrathin copper foil with a carrier in the conventional MSAP method. Therefore, it is possible to avoid problems such as residual copper after etching, pattern skipping due to side etching in fine patterns, and transmission loss of high-frequency signals due to the effects of irregularities. In addition, although the surface roughness is low, fine irregularities are densely present, so the insulating substrate and copper adhere well to each other.

[0072] [3] Step of forming a resist at a predetermined location on the surface of the seed layer. After peeling off the copper component, a resist is formed in a predetermined location on the surface of the seed layer. The location where the resist is formed is an area where copper, which will later form the circuit, will not be laminated.

[0073] The resist may include, for example, a material that hardens or dissolves upon exposure to light, and is not particularly limited, but is preferably formed of a dry film resist (DFR), a positive-type liquid resist, or a negative-type liquid resist.

[0074] The DFR preferably contains a binder polymer that contributes to film formation, and a monomer (for example, an acrylic ester or methacrylic ester monomer) and a photopolymerization initiator that undergo a photopolymerization reaction upon UV irradiation. For DFR formation, it is preferable to use a dry film having a three-layer structure of cover form / photoresist / carrier film. By peeling off the cover film, the photoresist is thermally pressed onto the structure and laminated, and after lamination the carrier film is peeled off, the DFR, which is a resist, can be formed on the structure.

[0075] Examples of liquid resists include novolac resins solubilized in organic solvents. Liquid resists can be applied to the surface of a structure, dried, and then irradiated with light to dissolve or harden the resist, thereby forming a new resist.

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

[0077] After forming the seed layer, and before forming the resist, the surface of the seed layer may be plated to form a second seed layer. The plating method is not particularly limited and may be electrolytic plating or electroless plating. For example, one metal selected from Ni, Sn, Al, Cr, Co, and Cu may be used, and a film may be formed using a known electroless plating method. Here, the second seed layer refers to a thin metal film formed by the plating process. The thickness of the second seed layer is not particularly limited and may be about 0.02 to 2 μm, but it is preferable that the total thickness, including the seed layer on the surface of the insulating substrate layer, be 2.5 μm or less.

[0078] [4] Copper lamination process Next, copper is deposited by copper plating the surface of the seed layer where the resist has not been layered. This deposited copper will later function as a circuit. The method of copper plating is not particularly limited, and the plating can be performed using known methods.

[0079] [5] Resist removal process The method for removing the resist is not particularly limited, and known methods such as using fuming nitric acid or sulfuric acid peroxide, or dry ashing using O2 plasma, can be used.

[0080] [6] Seed layer removal process The method for removing the seed layer is not particularly limited, and known methods such as quick etching or flash etching using a sulfuric acid-hydrogen peroxide-based etching agent can be used. [Examples]

[0081] (First example) Manufacturing of composite copper foil Examples 1-9 and Comparative Examples 2-3 used the shiny side (glossy surface; the flat side when compared to the opposite side) of copper foil (DR-WS, thickness: 18 μm) manufactured by Furukawa Electric Co., Ltd. Comparative Example 4 used the matte side of copper foil (FV-WS, thickness: 18 μm) manufactured by Furukawa Electric Co., Ltd., and the test specimen was prepared without any treatment.

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

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

[0084] (3) Pre-plating treatment After oxidation treatment, Examples 4-6 underwent pre-plating treatment using a solvent as described below. Example 4 involved treating a solution of 47.2 g / L of tin(II) chloride dihydrate and 1 mL / L of hydrochloric acid at 45°C for 10 seconds. Example 5 involved treating the sample with a 47.2 g / L solution of ammonium chloride at 45°C for 60 seconds. Example 6 involved treating the sample with a 6.5 mL / L solution of 50% citric acid at 45°C for 60 seconds.

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

[0086] For both the examples and comparative examples, multiple test specimens were prepared under the same conditions described above. Table 1 summarizes these conditions. [Table 1]

[0087] <2. Pressing and peeling off resin substrates> (1) Method For the test specimens of Examples 1-8 and Comparative Examples 2-4, peel tests of the resin substrate were performed 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, a prepreg was laminated onto the test specimen, and a laminated sample was obtained by thermocompression bonding in a vacuum using a vacuum high-pressure press. When the resin substrate was R5670KJ (manufactured by Panasonic), thermocompression bonding was performed by heating to 110°C under a pressure of 0.49 MPa, then increasing the temperature and pressure to 2.94 MPa and 210°C for 120 minutes. When the resin substrate was R5680J (manufactured by Panasonic), thermocompression bonding was performed by heating to 110°C under a pressure of 0.5 MPa, then increasing the temperature and pressure to 3.5 MPa and 195°C for 75 minutes. When the resin substrate was NX9255 (manufactured by Park Electrochemical), thermocompression bonding was performed by heating to 260°C under a pressure of 0.69 MPa, then increasing the pressure to 1.5 MPa and heating to 385°C, and holding at 385°C for 10 minutes. When the resin substrate was R1551GG (manufactured by Panasonic), the material was heated under a pressure of 1 MPa, held at 100°C for 10 minutes, then heated further under a pressure of 3.3 MPa, held at 180°C for 50 minutes, and then heat-compressed. When the resin substrate was CT-Z (manufactured by Kuraray), the material was heated under a pressure of 0 MPa, held at 260°C for 15 minutes, then heated further under a pressure of 4 MPa, held at 300°C for 10 minutes, and then heat-compressed. The copper component was peeled off the resin substrate of these laminated samples in accordance with a 90° peel test (Japanese Industrial Standard (JIS) C5016). The results of visual observation are shown in Figure 2-1. In addition, photographs of the resin side and copper foil side surfaces after peeling are shown in Figure 2-2 for representative combinations.

[0089] From Figure 2, it can be easily observed that in the embodiment, the surface of the copper foil has transferred to the resin side, whereas in the comparative example, the surface of the copper foil has not transferred to the resin side. To prove this materially, surface analysis was performed as follows.

[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 QuanteraSXM (ULVAC-PHI) under the following conditions. As a negative control, an untreated resin substrate (R5670KJ;MEGTRON6) was analyzed (Comparative Example 1).

[0091] (1) Survey spectrum First, the elements were detected under the following conditions. X-ray light source: Monochromatic Al Kα (1486.6eV) X-ray beam diameter: 100 μm (25 watts, 15 kV) Pass energy: 280 eV, 1 eV step Point analysis: φ100μm Total number of times: 8 The results are shown in Table 2 and Figure 3.

[0092] (2) Results In the example, the peak intensity of the Cu2p3 spectrum derived from the transferred copper atoms was greater than the peak intensity of the C1s spectrum derived from the resin substrate, whereas in the comparative example, the Cu2p3 spectrum peak was not detected, or its intensity was less than the peak intensity 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 surface layer of the resin substrate that could be detected by XPS.

[0093] In Example 1, since the composite copper foil was not plated, only Cu atoms were transferred and detected on the resin substrate side. In Examples 2 and 3, since the Ni plating was applied, both Cu and Ni atoms were transferred and detected on the resin side.

[0094] Furthermore, the proportion of C1s was lower in all of the examples compared to the comparative examples. In the examples, it is thought that the proportion of C1s on the surface was relatively lower due to the transfer of copper oxide or cuprous oxide. [Table 2]

[0095] <4. Measurement of Ra and surface area of ​​composite copper foil before and after heat-compression bonding> (1) Method For the composite copper foil test pieces of Examples 1-8 and Comparative Examples 2-4, the surface area before and after thermocompression bonding was calculated using a confocal microscope OPTELICS H1200 (Lasertec Corporation). The measurement conditions were: confocal mode, scan area 100 μm × 100 μm, light source Blue, and cutoff value 1 / 5. The object lens was set to x100, the contact lens to x14, the digital zoom to x1, and the Z pitch to 10nm. Data was acquired from three locations, and the surface area was calculated as the average of the three locations.

[0096] (2) Results As shown in Table 3, in the examples, Ra and surface area decreased after peeling compared to before heat bonding, while in the comparative example, they increased. This indicates that in the examples, all or part of the convex portion of the composite copper foil was transferred to the resin side, whereas in the comparative example, part of the resin was transferred to the composite copper foil. [Table 3]

[0097] <5. ΔE of composite copper foil before and after heat bonding * Calculation of ab > (1) Method Color difference (L) of the copper foil surface of each composite copper foil test piece before and after heat compression bonding. * a * , b * ) is measured, and from the obtained value, ΔE is calculated according to the following formula. * ab was calculated. ΔE * ab = [(ΔL * ) 2 + (Δa * ) 2 + (Δb * ) 2 ] 1 / 2

[0098] (2) Results As shown in Table 4, ΔE in the example was observed before and after heat bonding and peeling. * In the example, ab was 15 or higher, while in the comparative example it was less than 15. This is because, in the example, the metal contained in the copper oxide layer is transferred to the resin substrate, resulting in a large color change of the copper component, whereas in the comparative example, the copper oxide layer remains on the copper component, resulting in a smaller color change of the copper component. Therefore, the more metal contained in the copper oxide layer is transferred, the greater the difference between the two. In fact, as shown in the photograph in Figure 2, after peeling, the resin side is significantly discolored in the example, but in the comparative example, the resin side remains almost white. [Table 4]

[0099] <5. Analysis of the composite copper foil surface after transition using attenuated total reflectance absorption Fourier transform infrared spectroscopy (FT-IR / ATR method)> (1) Method As resin substrates, R1551GG (epoxy), R5670KJ, R5680J (all PPE), NX9255 (PTFE), or CT-Z (LCP) were used for thermocompression bonding, and each composite copper foil test piece after peeling was analyzed by FT-IR / ATR under the following measurement conditions. Measurement conditions Parkin Elmer Specrtum 100 ATR method Crystal: Germanium Resolution: 4 Number of scans: 4 Pressure (force gauge): 40±5 [N] Spectral display: Absorbance

[0100] (2) Calculation of the S / N (Signal-to-Noise) ratio After heating and pressurizing only the resin substrate under the same conditions as when heat-pressing it with composite copper foil, the resin substrate was measured using FT-IR, and an arbitrary wavelength without resin-derived peaks was set to 50 cm. -1The range was selected. In this example, 3800-3850 cm -1 This wavelength was chosen to be free of peaks originating from the resin. Furthermore, the wavelength range is 700-4000 cm. -1 In this study, the wavelength at which the maximum peak was detected was identified. When R1551GG was used as the resin substrate, the wavelength was 1200 cm². -1 Nearby, when using R5670KJ and R5680J, the measurement is 1190cm. -1 Nearby, using NX9255, the measurement is 1232cm. -1 In the vicinity, using CT-Z, the measurement is 1741 cm. -1 The wavelength in the vicinity was used to detect the maximum peak (the arrows in Figures 4-8 indicate the wavelength of maximum peak detection).

[0101] The copper surface after the transition was measured using FT-IR. A baseline was drawn by connecting the poles at both ends of the peak at the maximum peak detection wavelength, and the difference between the baseline and the maximum peak height was defined as the signal value (S). Wavelength: 3800–3850 cm -1 In this study, the difference between the maximum and minimum values ​​of the detected peaks was defined as the noise value (N), and the signal-to-noise ratio (S / N ratio) was calculated.

[0102] (3) Results The results are shown in Figures 4-8 and Table 5. [Table 5]

[0103] As shown in Table 5, in the embodiment, no peaks with an S / N ratio of 10 or higher corresponding to resin-derived organic matter were detected on the composite copper foil side. However, in the comparative example, peaks with an S / N ratio of 10 or higher corresponding to resin-derived organic matter were detected on the composite copper foil side.

[0104] This is because, in the comparative example, the metal on the surface of the composite copper foil hardly transferred, and when the composite copper foil was peeled off the resin substrate, cohesive failure of the resin occurred, and the broken resin adhered to the surface of the composite copper foil, resulting in the detection of peaks corresponding to organic matter derived from the resin. On the other hand, in the example, the metal on the surface of the composite copper foil transferred to the resin substrate, so there was almost no resin adhesion to the composite copper foil after it was peeled off the resin substrate, and no peaks with an S / N ratio of 10 or higher corresponding to organic matter derived from the resin were detected.

[0105] In other words, in the comparative example, the strength of the protrusions 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 migrate, and cohesive failure of the resin occurs. On the other hand, in the example, the strength of the protrusions 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 migrates, resulting in almost no resin adhesion.

[0106] (Second embodiment) Circuit formation The circuit was formed using the composite copper foil of Example 3 in the first embodiment. First, a composite copper foil was fabricated using the shiny side (glossy surface; the flat side when compared to the opposite side) of a copper foil (DR-WS, thickness: 18 μm) manufactured by Furukawa Electric Co., Ltd., by processing it under the following conditions.

[0107] (1) Pretreatment Copper foil was immersed 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 pre-treated copper foil was oxidized by immersion in an oxidizing agent. A solution containing 46.3 g / L sodium chlorite, 12.3 g / L potassium hydroxide, and 2.1 g / L KBM-403 (3-glycidoxypropyltrimethoxysilane; manufactured by Shin-Etsu Silicone Co., Ltd.) was used as an oxidizing agent, and the samples were immersed in the solution at 73°C for 2 minutes.

[0109] (3) Electroplating After oxidation treatment, electroplating was performed using a Ni electroplating solution (nickel sulfate 255 g / L; nickel chloride 49 g / L; sodium citrate 20 g / L). The sample was immersed in the Ni electroplating solution for 1 minute before electroplating. Current density: 0.5 A / dm² at 50°C. 2 ×45 seconds (=22.5C / dm 2 Electroplating was performed on the copper foil area.

[0110] Next, a copper-clad laminate R-5775 (manufactured by Panasonic), which consists of a 0.5 mm thick substrate laminated with 18 μm copper foil on both sides, 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 that order, vacuum laminated, and then held at 180°C for 30 minutes to obtain a laminated substrate.

[0111] Subsequently, the composite copper foil was peeled off by hand, and the fine irregularities formed on the composite copper foil were transferred to the resin substrate, thereby forming a seed layer on the resin substrate. A commercially available photosensitive dry film was attached to the formed seed layer, exposed through a mask, and developed with 0.8% sodium bicarbonate to form a plating resist.

[0112] Then, using a commercially available electrolytic copper plating solution, the current density was 1 A / dm 2 A 15 μm thick electrolytic copper plating film was formed by electrolytic copper plating at 30°C for 30 minutes.

[0113] Furthermore, after stripping off the plating resist with 5% potassium hydroxide, a laminated wiring circuit board was obtained by dissolving and removing the seed layer beneath the plating resist using etching with a mixture of sulfuric acid and hydrogen peroxide (Figure 9). In this way, a laminated wiring circuit board can be obtained by bonding a copper member having protrusions on its surface to an insulating substrate layer, peeling off the copper member to transfer the protrusions to the surface of the insulating substrate layer, and forming a seed layer.

Claims

1. A method for manufacturing a laminate of an insulating substrate layer and copper, A step of bonding the insulating substrate layer and a copper member having protrusions on its surface, The process involves peeling off the copper member to transfer the protrusions to the surface of the insulating substrate layer and forming a seed layer, A step of forming a resist at a predetermined location on the surface of the seed layer, The process of laminating copper by copper plating the surface of the seed layer in areas where the resist is not laminated, The step of removing the resist, A step of removing the seed layer exposed by the removal of the resist, Includes, A manufacturing method wherein the thickness of the seed layer is 0.01 to 1.70 μm.

2. A method for manufacturing a laminate of an insulating substrate layer and copper, A step of bonding the insulating substrate layer and a copper member having protrusions on its surface, The process involves peeling off the copper member to transfer the protrusions to the surface of the insulating substrate layer and forming a seed layer, A step of forming a resist at a predetermined location on the surface of the seed layer, The process of laminating copper by copper plating the surface of the seed layer in areas where the resist is not laminated, The step of removing the resist, A step of removing the seed layer exposed by the removal of the resist, Includes, The copper member having a protrusion on its surface, 1) A step of partially coating the surface of the copper component to be used as material with a silane coupling agent or a preservative, and 2) A step of forming a layer containing copper oxide by oxidizing the partially coated surface. A manufacturing method formed by [the following].

3. The manufacturing method according to claim 1 or 2, wherein the protrusions on the surface of the copper member are formed on the surface of the copper member by chemical treatment.

4. The manufacturing method according to any one of claims 1 to 3, wherein no protrusions are formed on the surface of the insulating substrate layer by desmear treatment.

5. The manufacturing method according to any one of claims 1 to 4, wherein the copper plating treatment is an electrolytic copper plating treatment.

6. The manufacturing method according to any one of claims 1 to 5, wherein between the step of forming the seed layer and the step of forming the resist, a step of electroless plating the surface of the seed layer is performed.

7. The substrate used in the insulating substrate layer is a resin substrate, The manufacturing method according to any one of claims 1 to 6, wherein the insulating substrate layer and the copper member are bonded together by thermocompression bonding.

8. When the surface of the copper member peeled off from the insulating substrate layer was analyzed using attenuated total reflectance absorption Fourier transform infrared spectroscopy (FT-IR / ATR method), the wavelength range was 700–4000 cm. －１ The manufacturing method according to claim 7, wherein the signal-to-noise ratio of the peak corresponding to the substance derived from the resin substrate detected is 10 or less.

9. The manufacturing method according to claim 8, wherein the signal-to-noise ratio of the peak is 7 or less.

10. The manufacturing method according to claim 7, wherein when Survey Spectrum analysis is performed on the surface of the resin substrate from which the copper member has been peeled off by X-ray photoelectron spectroscopy (XPS), metal atoms contained in the copper member are detected from the surface of the resin substrate from which the copper member has been peeled off in the obtained X-ray photoelectron spectroscopy spectrum.

11. The manufacturing method according to claim 10, wherein the sum of the main peak intensities of the metal elements detected from the surface of the resin substrate from which the copper member has been peeled off is greater than the peak intensity of C1s.

12. Calculated from the XPS measurement mentioned above [Total surface atomic composition percentage of metal elements (Atom%)] / [Surface atomic composition percentage of C1s (Atom%)] The manufacturing method according to claim 10, wherein is 0.03 or more.

13. Calculated from the XPS measurement mentioned above [Total surface atomic composition percentage of metal elements (Atom%)] / [Surface atomic composition percentage of C1s (Atom%)] The manufacturing method according to claim 10, wherein is 0.04 or more.

14. The manufacturing method according to claim 7, wherein when Survey spectrum analysis is performed on the surface of the resin substrate from which the copper member has been peeled off by X-ray photoelectron spectroscopy (XPS), the sum of the surface atomic composition percentages of Cu2p3 and Ni2p3 is 3.0 atom% or more.

15. The manufacturing method according to claim 7, wherein when Survey spectrum analysis is performed on the surface of the resin substrate from which the copper member has been peeled off by X-ray photoelectron spectroscopy (XPS), the sum of the surface atomic composition percentages of Cu2p3 and Ni2p3 is 1.5 atom% or more.

16. The manufacturing method according to claim 7, wherein when Survey spectrum analysis is performed on the surface of the resin substrate from which the copper member has been peeled off by X-ray photoelectron spectroscopy (XPS), the surface atomic composition percentage of Cu2p3 is 2.8 atom% or more.

17. The manufacturing method according to claim 7, wherein when Survey spectrum analysis is performed on the surface of the resin substrate from which the copper member has been peeled off by X-ray photoelectron spectroscopy (XPS), the percentage of surface atomic composition of Cu2p3 is 1.0 atom% or more.

18. The copper member having a protrusion on its surface, 1) A step of forming a layer containing copper oxide by oxidizing the surface of a copper component to be used as material, and 2) The manufacturing method according to any one of claims 1 to 17, wherein the oxidized surface is formed by the step of treating it with a solvent that dissolves the copper oxide.

19. The manufacturing method according to claim 18, wherein the solvent is selected from the group consisting of potassium chloride, nickel chloride, zinc chloride, iron chloride, chromium chloride, ammonium citrate, ammonium chloride, ammonium sulfate, nickel ammonium sulfate, ethylenediaminetetraacetic acid, diethanolglycine, 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)iminodiacetate, and sodium gluconate.

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