Transfer laminate, wiring body, and wiring body manufacturing method

Abstract

Provided is a transfer laminate that has improved die cutting properties during transfer in hot stamping and thus makes it possible to form circuit patterns with high accuracy. This transfer laminate comprises a support, a release layer, and a copper layer in the stated order. When the copper layer is subjected to elemental analysis using glow discharge optical emission spectrometry (GD-OES), the C concentration in the copper layer is 0.010 mass% or more.

Description

Transfer laminate, wiring, and method for manufacturing wiring

[0001] This disclosure relates to a transfer laminate, a wiring harness, and a method for manufacturing a wiring harness.

[0002] Hot stamping is a known method for applying metallic luster decorations to packaging paper and the like. In this method, for example, a metallic film is used in which a release layer, a coloring layer, an aluminum vapor-deposited layer, and an adhesive layer are provided in that order on the surface of a polyethylene terephthalate (PET) film. By pressing a plate (stamp) with a predetermined pattern of convex surfaces onto the PET film and subjecting it to heating and pressure treatment, the aluminum vapor-deposited layer and the coloring layer can be transferred to the packaging paper or the like via the adhesive layer.

[0003] It has also been proposed to use such hot stamping method patterning to form circuits on printed circuit boards. For example, Patent Document 1 (Japanese Unexamined Patent Publication No. 57-193092) discloses a transfer foil having an electrical functional layer for creating an electrical functional circuit on an electrically insulating substrate. This document also discloses the creation of a functional layer using fibers having an axis substantially perpendicular to the foil surface, which is said to weaken the shear strength and allow for clear separation of the functional layer during transfer. Furthermore, Patent Document 2 (Japanese Unexamined Patent Publication No. 60-147400) discloses a transfer sheet for manufacturing printed circuit boards, which is constructed by laminating a thin metal film layer on one side of an organic resin film containing an antistatic agent, and then providing an adhesive layer on top of that, which is said to eliminate the need for a release agent layer.

[0004] JP-A-57-193092 JP-A-60-147400

[0005] By using a transfer laminate equipped with a copper layer to form circuits such as printed circuit boards using the hot stamping method, it is possible to reduce the number of steps and the environmental impact by eliminating the use of chemicals (e.g., etching solutions) compared to conventional circuit formation methods such as the subtractive and additive methods. However, when transferring the copper layer to the transfer target using the hot stamping method, it may be difficult to accurately pattern the circuits due to the poor die-cutting properties of the transfer laminate.

[0006] The present inventors have now discovered that in a transfer laminate comprising a support, a release layer, and a copper layer in that order, controlling the C concentration in the copper layer to 0.010% by mass or more improves the moldability during transfer by the hot stamping method, enabling the formation of circuit patterns with high precision.

[0007] Therefore, the object of the present invention is to provide a transfer laminate that improves the demolition performance during transfer by the hot stamping method and enables the formation of circuit patterns with high precision.

[0008] The following embodiments are provided according to this disclosure: [Embodiment 1] A transfer laminate comprising a support, a release layer, and a copper layer in this order, wherein the C concentration in the copper layer is 0.010 mass% or more when the copper layer is elementally analyzed by glow discharge emission spectrometry (GD-OES). [Embodiment 2] The transfer laminate according to Embodiment 1, wherein the product of the C concentration (mass%) of the copper layer and the thickness (μm) of the copper layer is 0.005 mass%・μm or more and 1.650 mass%・μm or less. [Embodiment 3] The transfer laminate according to Embodiment 1 or 2, wherein the copper layer has a thickness of 0.1 μm or more and 10 μm or less. [Embodiment 4] The transfer laminate according to any one of Embodiments 1 to 3, wherein the support is a copper foil with a thickness of 7 μm or more and 18 μm or less. [Embodiment 5] The transfer laminate according to any one of Embodiments 1 to 4, further comprising an adhesive layer on the side of the copper layer opposite to the release layer. [Aspect 6] A wiring body including a circuit formed using a transfer laminate according to any one of aspects 1 to 5. [Aspect 7] A method for manufacturing a wiring body, comprising: a step of laminating a transfer laminate according to any one of aspects 1 to 5 onto the surface of a transfer body such that the adhesive layer and the transfer body are in contact; a step of applying heat and pressure to the support-side surface of the transfer laminate laminated onto the transfer body using a plate having a convex surface in the shape of a circuit pattern, thereby adhering the adhesive layer corresponding to the circuit pattern to the transfer body; and a step of peeling the transfer laminate from the transfer body after the heat and pressure treatment, thereby transferring the copper layer to the surface of the transfer body in the shape of a circuit pattern via the adhesive layer. [Aspect 8] A method for manufacturing a wiring body, comprising: a step of laminating a transfer laminate according to any one of aspects 1 to 5 onto the surface of a transfer body such that the copper layer and the transfer body are in contact; a step of applying heat and pressure treatment to the support-side surface of the transfer laminate laminated onto the transfer body using a plate having a circuit pattern-shaped convex surface, thereby directly adhering the copper layer corresponding to the circuit pattern to the transfer body; and a step of peeling the transfer laminate from the transfer body after the heat and pressure treatment, thereby transferring the copper layer to the surface of the transfer body in the shape of the circuit pattern.[Aspect 9] The method for manufacturing a wiring body according to aspect 7 or 8, wherein the material to be transferred contains a resin having a melting point of 100°C or more and 350°C or less. [Aspect 10] The method for manufacturing a wiring body according to any one of aspects 7 to 9, wherein the heating temperature in the heat-pressure treatment is 100°C or more and 400°C or less, and the heating temperature is equal to or greater than the melting point of the material to be transferred. [Aspect 11] A method for manufacturing a wiring body, comprising: a step of laminating an adhesive layer in the shape of a circuit pattern on the surface of the material to be transferred; a step of laminating a transfer laminate according to any one of aspects 1 to 5 on the surface of the material to be transferred on which the adhesive layer is laminated, such that the copper layer and the adhesive layer are in contact; a step of performing a heat-pressure treatment on the support-side surface of the transfer laminate laminated on the material to be transferred, thereby bonding the copper layer and the material to be transferred to the adhesive layer; and a step of peeling the transfer laminate after the heat-pressure treatment from the material to be transferred, thereby transferring the copper layer in the shape of a circuit pattern to the surface of the material to be transferred via the adhesive layer. [Aspect 12] The method for manufacturing a wiring body according to aspect 11, wherein the lamination of the adhesive layer onto the transfer body is performed by printing using at least one selected from the group consisting of a laser printer, an inkjet printer, and screen printing.

[0009] This is a schematic cross-sectional view showing an example of a transfer laminate according to the present disclosure. This is a schematic cross-sectional flow diagram showing an example of a method for manufacturing a wiring harness according to the present disclosure. This is a schematic cross-sectional view showing an example of a case where foil residue occurs on the material to be transferred. This is an example of a C concentration depth profile obtained by glow discharge emission spectrometry (GD-OES). This is an optical microscope image of the PET film surface after copper layer transfer obtained in Example 2, showing a case with good dieability. This is an optical microscope image of the PET film surface after copper layer transfer obtained in Example 6, showing a case where foil residue occurs. This is a laser microscope image of the PET film surface after copper layer transfer obtained in Example 1, showing a case with good dieability.

[0010] Figure 1 shows an example of a transfer laminate according to this disclosure. The transfer laminate 10 comprises a support 12, a release layer 14, and a copper layer 16 in this order.Optionally, the transfer laminate 10 may further comprise an adhesive layer 18 on the side of the copper layer 16 opposite to the release layer 14.When the copper layer 16 is elementally analyzed by glow discharge emission spectrometry (GD-OES), the C concentration in the copper layer 16 is 0.010 mass% or more.In this specification, C in the notation "C concentration" is an element symbol used as an abbreviation for carbon.In this way, by controlling the C concentration in the copper layer 16 to 0.010 mass% or more in the transfer laminate 10 comprising the support 12, release layer 14, and copper layer 16 in this order, good die-cutting performance by hot stamping method and accurate formation of circuit patterns can be achieved.

[0011] Figure 2 shows an example of a transfer method using the hot stamping method. First, as shown in Figure 2(a), a transfer laminate 10 comprising a support 12, a release layer 14, a copper layer 16, and an adhesive layer 18 is laminated onto the surface of the object to be transferred 20. This lamination is carried out so that the object to be transferred 20 and the adhesive layer 18 are in contact. Next, as shown in Figure 2(b), a heating and pressing treatment is performed on the support 12 side surface of the transfer laminate 10 using a plate having a circuit pattern-shaped convex surface (hereinafter sometimes referred to as "relief plate 22"). In this way, the heat from the relief plate 22 is transferred to the adhesive layer 18 via the support 12, the release layer 14, and the copper layer 16. At this time, the part of the adhesive layer 18 to which heat is transferred (heat transfer part 18a) is the part corresponding to the circuit pattern of the relief plate 22 (the part directly below the circuit pattern of the relief plate 22). Then, the adhesive layer 18 and the object to be transferred 20 are bonded at the heat transfer part 18a. Subsequently, as shown in Figure 2(c), the support 12 is peeled off the transfer target 20. At this time, only the heat transfer portion 18a of the adhesive layer and the portion of the copper layer 16 that is in contact with the heat transfer portion 18a remain on the surface of the transfer target 20, while the remaining portion (unreacted portion) is peeled off from the transfer target 20 together with the support 12. In this way, the copper layer 16 can be die-cut into a predetermined pattern to form a circuit.

[0012] However, as shown in Figure 3, when forming circuits using hot stamping, the copper layer 16 may not be able to be cut out at the intended position, resulting in foil residue. One of the reasons for this is that heat diffuses during the heating and pressing process, causing the heat transfer area to expand beyond the original pattern. This problem is conveniently solved by using the transfer laminate 10 of this disclosure. Specifically, by increasing the C concentration in the copper layer 16 to 0.010 mass% or higher, the copper crystals constituting the copper layer 16 can be made finer. As a result, the copper layer 16 becomes more brittle, improving its cutout properties, and it is believed that unintended foil residue of the copper layer 16 can be effectively suppressed when the support 12 is peeled off from the transfer object 20. Therefore, circuit patterns can be formed with high precision using the hot stamping method with the transfer laminate 10.

[0013] When the copper layer 16 is elementally analyzed by glow discharge emission spectrometry (GD-OES), the carbon concentration in the copper layer 16 is 0.010% by mass or more, preferably 0.010% by mass or more and 0.170% by mass or less, and more preferably 0.050% by mass or more and 0.120% by mass or less. By keeping it within the above range, it is possible to improve the moldability of the copper layer 16 while controlling the brittleness of the copper layer 16 and effectively suppressing the formation of holes in the copper layer 16.

[0014] Elemental analysis by GD-OES is performed while digging down by sputtering from the surface on the copper layer 16 side of the transfer laminate 10 toward the support 12. By doing this, a depth profile of C concentration as shown in FIG. 4 can be obtained. In the depth profile shown in FIG. 4, the horizontal axis corresponds to the depth direction from the surface on the copper layer 16 side of the transfer laminate 10 toward the support 12, and the vertical axis corresponds to the C concentration. As shown in FIG. 4, in the depth profile of the transfer laminate 10 of the present disclosure, the surface of the copper layer 16 has a high C concentration due to the influence of unavoidable contamination, adhesion treatment agent, etc., and the C concentration gradually decreases as progressing toward the inside of the copper layer 16. Thereafter, the C concentration shows a generally constant value (even though some fluctuations or steps may exist), and when approaching the release layer 14, a peak due to an increase in C concentration is inevitably observed due to the influence of C contained in the release layer 14 and the like. For this reason, the C concentration of the copper layer 16 in the present specification is calculated at a depth position that is not affected by C on the surface of the copper layer 16 and in the vicinity of the release layer 14. Specifically, in the range where the C concentration on the surface of the copper layer 16 decreases, a tangent line L is drawn so that the correlation coefficient is maximized １ . Further, in the range where the C concentration shows a constant value, a tangent line L is drawn so that the correlation coefficient is maximized ２ . Furthermore, at the peak where the C concentration increases in the vicinity of the release layer 14, a tangent line L is drawn so that the correlation coefficient is maximized ３ . Then, the intersection of L １ and L ２ is defined as X １ , and the intersection of L ２ and L ３ is defined as X ２ , and the midpoint of the distance between the intersection of X １ and X ２ is calculated. The C concentration is calculated by averaging the C concentrations at the sputtering depths corresponding to the front and back of this midpoint. For the depth profile, a total of 3 data points are obtained by changing the measurement position, the above C concentration is calculated for each data point, and the average value of the C concentrations of the 3 points is taken as the C concentration in the copper layer 16. Preferred measurement conditions for GD-OES will be shown in the examples described later.

[0015] The above measurement method is merely an example, and it is permissible to change the method for identifying each layer and the method for calculating the C concentration depending on the type and properties of the peeling layer 14 and the copper layer 16. That is, if the main component constituting the peeling layer 14 is an element other than C, the peeling layer 14 may be identified based on the element derived from that main component. For example, if the peeling layer 14 contains Ni or Cr, the depth profile of Ni or Cr concentration can be obtained in addition to the depth profile of C concentration using GD-OES, and the depth position of the peeling layer 14 can be identified based on the peak due to the increase in Ni or Cr concentration in the depth profile. Furthermore, if the C concentration in the copper layer 16 is not flat in the depth profile, and one or more peaks other than the peak corresponding to the surface of the copper layer 16 are observed, the peak closest to the peak of the peeling layer 14 (hereinafter referred to as the "selected peak") can be selected, and the C concentration can be calculated by drawing a tangent line in the same manner as above. Specifically, for the selected peak, a tangent line L is drawn such that the correlation coefficient is largest in the range where the C concentration decreases (peak drop-off portion). １ Draw a line. Also, draw a tangent line L in the valley between the selected peak and the peak of the delamination layer 14 so that the correlation coefficient is largest. ２ Draw a line. Furthermore, draw a line L tangent to the peak of the peeling layer 14 such that the correlation coefficient is largest in the range where the C concentration increases (peak rise portion). ３ Subtract L. Then, as above, １ and L ２ Intersection X １ And, L ２ and L ３ Intersection X ２ By calculating the midpoint between two points and averaging the carbon concentrations at the sputtering depths corresponding to the midpoint, the carbon concentration can be calculated.

[0016] The thickness of the copper layer 16 is preferably 0.1 μm to 10 μm, more preferably 0.1 μm to 5 μm, even more preferably 0.1 μm to 2.0 μm, and particularly preferably 0.4 μm to 1.0 μm. Such a thickness further improves die-cutting performance. In particular, the product of the C concentration (mass%) of the copper layer and the thickness (μm) of the copper layer is preferably 0.005 mass%·μm to 1.650 mass%·μm, more preferably 0.005 mass%·μm to 0.850 mass%·μm, even more preferably 0.020 mass%·μm to 0.170 mass%·μm, and particularly preferably 0.020 mass%·μm to 0.049 mass%·μm. This improves the foil cutting performance of the copper layer 16, further improving die-cutting performance.

[0017] When the copper layer 16 is analyzed by X-ray diffraction (XRD), the crystallite size calculated from the diffraction peak of the (111) plane is preferably 500 Å or less, more preferably 100 Å to 500 Å, and even more preferably 181 Å to 300 Å. This further improves the moldability of the copper layer 16 while controlling its brittleness and more effectively suppressing the formation of holes in the copper layer 16.

[0018] By analyzing the copper layer 16 with XRD, diffraction peaks of the (111), (200), (220), and (311) crystal planes of Cu can be obtained. Of these diffraction peaks, the (111) plane has the highest peak intensity; therefore, in this specification, the crystallite size will be calculated from the diffraction peak of the (111) plane. This crystallite size can be calculated using Scherrer's formula shown below: D = (K × λ) / (β × cosθ) (wherein D is the crystallite size (Å), K is Scherrer's constant, λ is the wavelength of X-rays (Å), β is the full width at half maximum of the diffraction peak (rad), and θ is the Bragg angle (rad)), with Scherrer's constant K set to 0.94. Preferred measurement conditions for XRD are shown in the examples described later.

[0019] Various surface treatments may be applied to the surface of the copper layer 16 as desired. Examples of such surface treatments include roughening treatment, rust prevention treatment, and silane coupling agent treatment. These surface treatments may be known treatments performed on copper foil for printed circuit board formation (e.g., copper foil with carrier), and are not particularly limited. If the transfer laminate 10 further includes an adhesive layer 18 on the surface facing the copper layer 16, it is preferable to perform the above surface treatment before forming the adhesive layer 18.

[0020] The support 12 is a support for supporting the copper layer 16 and improving its handling properties. Preferred materials for the support 12 include metal, resin, glass, paper, and composites thereof. Preferred metals for the support 12 include copper (e.g., copper foil) and aluminum (e.g., aluminum foil). Preferred resins for the support 12 include polyethylene terephthalate (PET) and polyimide. The support 12 may take the form of a sheet, film, or plate. The support 12 may also be a laminate of these sheets, films, and plates. When subjected to heat and pressure treatment at high temperatures (e.g., 200°C or higher), it is preferable that the support 12 be made of metal (e.g., copper) from the viewpoint of minimizing deformation and distortion due to heat.

[0021] The support 12 is particularly preferably made of copper foil. Using copper foil for the support 12 has the advantage of lower environmental impact compared to resin films, etc., because copper can be easily recycled. The support 12 is preferably made of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, more preferably of copper foil, and in particular, using copper foil of the above thickness as the support 12 improves handling properties and the transfer of pressure and heat from the relief plate 22 during hot stamping, thereby further improving die-cutting performance.

[0022] The release layer 14 has functions of reducing the peeling strength of the support 12 when peeling the support 12 from the transfer receiving body 20, ensuring the stability of said strength, and further suppressing interdiffusion that may occur between the support 12 and the copper layer 16 during hot stamping. The release layer 14 is generally formed on one surface of the support 12, but may be formed on both surfaces of the support 12.

[0023] The release layer 14 may be either an organic release layer or an inorganic release layer. Examples of organic components used for the organic release layer include nitrogen-containing organic compounds, sulfur-containing organic compounds, and carboxylic acids. Examples of the nitrogen-containing organic compounds include triazole compounds and imidazole compounds; among these, triazole compounds are preferred because they easily provide stable release properties. Examples of the triazole compounds include 1,2,3-benzotriazole, carboxybenzotriazole, N',N'-bis(benzotriazolylmethyl)urea, 1H-1,2,4-triazole, and 3-amino-1H-1,2,4-triazole. Examples of the sulfur-containing organic compounds include mercaptobenzothiazole, thiocyanuric acid, and 2-benzimidazolethiol. Examples of the carboxylic acids include monocarboxylic acids and dicarboxylic acids. On the other hand, examples of inorganic components used for the inorganic release layer include Cu, Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, and chromate-treated films. The thickness of the release layer 14 is typically 1 nm or more and 1 μm or less, and preferably 5 nm or more and 500 nm or less.

[0024] Another functional layer may be provided between the release layer 14 and the support 12 and / or the copper layer 16. An example of such another functional layer is an auxiliary metal layer. The auxiliary metal layer is preferably composed of nickel and / or cobalt. By forming such an auxiliary metal layer on the surface side of the support 12 and / or the surface side of the copper layer 16, interdiffusion that may occur between the support 12 and the copper layer 16 during hot stamping can be further suppressed, and the stability of the peeling strength of the support 12 can be ensured. The thickness of the auxiliary metal layer is preferably 0.001 μm or more and 3 μm or less.

[0025] It is preferable that the transfer laminate 10 further comprises an adhesive layer 18 on a surface of the copper layer 16 opposite to the release layer 14. The adhesive layer 18 is a layer having a function of adhering the copper layer 16 to a transfer target 20 by heat and pressure treatment. The adhesive layer 18 may be formed by drying a known adhesive for hot stamping. The type of adhesive constituting the adhesive layer 18 is not particularly limited, but is preferably, for example, an acrylic adhesive, an epoxy adhesive, a urethane adhesive, a silicone adhesive, or a combination thereof. The adhesive layer may be any of a thermosetting adhesive, a hot-melt adhesive, a pressure-sensitive adhesive, or a photo-curable adhesive, or may be a mixture of these. As the hot-melt adhesive, for example, acrylate-vinyl chloride copolymer, polyvinyl butyral, polyvinyl acetate, and vinyl chloride-vinyl acetate copolymer can be preferably used. The thickness of the adhesive layer 18 is not particularly limited, but is preferably 0.1 µm or more and 5.0 µm or less, more preferably 0.1 µm or more and 3.0 µm or less.

[0026] Method for Producing Transfer Laminate The transfer laminate 10 of the present disclosure can be preferably produced by: (1) preparing a support 12, (2) forming a release layer 14 on the support 12, (3) forming a copper layer 16 on the release layer 14, and (4) forming an adhesive layer 18 on the copper layer 16 as desired. An example of a preferred method for producing the transfer laminate 10 according to the present disclosure will be described below.

[0027] (1) Preparation of Support First, a support 12 is prepared. Preferred examples of the support 12 are as described above, and copper foil is particularly preferred. The copper foil may be either rolled copper foil or electrolytic copper foil, but electrolytic copper foil is preferred.

[0028] When using electrolytic copper foil as the support 12, electrolytic foil manufacturing can be performed using a sulfuric acid-based copper electrolyte under known conditions. It is preferable that the surface of the support 12 on the side of the release layer 14 is smooth. That is, in the manufacturing process of the transfer laminate 10, a copper layer 16 will be formed on the surface of the support 12 on the side of the release layer 14. Therefore, by making the surface of the support 12 on the side of the release layer 14 smooth, it becomes easier to make the crystal growth surface of the copper layer 16 uniform. As a result, it becomes easier to obtain a copper layer 16 composed of copper crystals having the desired crystallite size. To make the surface of the support 12 on the side of the release layer 14 smooth, for example, the surface roughness can be adjusted by polishing the surface of the cathode used when electrolytically manufacturing the support 12 with a buff of a predetermined grit. That is, the surface profile of the cathode thus adjusted is transferred to the electrode surface of the support 12, and by forming the copper layer 16 on this electrode surface of the support 12 via the release layer 14, it becomes easier to form a copper layer 16 composed of copper crystals of the predetermined crystallite size. The preferred buff grit is between #1,000 and #3,500, and more preferably between #1,000 and #2,500.

[0029] (2) Formation of the release layer A release layer 14 is formed on the support 12. The release layer 14 may be either an organic release layer or an inorganic release layer. Preferred examples of the organic release layer and the inorganic release layer are as described above. The release layer 14 can be formed by contacting a solution containing the release layer component with at least one surface of the support 12 and fixing the release layer component to the surface of the support 12. When the support 12 is brought into contact with the solution containing the release layer component, this contact can be done by immersion in the solution containing the release layer component, spraying the solution containing the release layer component, or letting the solution containing the release layer component flow down. In addition, methods for forming a film of the release layer component by vapor phase methods such as vapor deposition or sputtering can also be employed. Furthermore, the release layer component can be fixed to the surface of the support 12 by adsorption or drying of the solution containing the release layer component, or by electrodeposition of the release layer component in the solution containing the release layer component. The thickness of the release layer 14 is typically 1 nm or more and 1 μm or less, preferably 5 nm or more and 500 nm or less.

[0030] In particular, it is preferable to use a CBTA-containing sulfuric acid copper solution as the release layer component, with a copper concentration of 10 g / L to 50 g / L, a free sulfuric acid concentration of 100 g / L to 200 g / L, and a carboxybenzotriazole (CBTA) concentration of 200 ppm to 400 ppm. By doing so, a release layer 14 containing CBTA as a component can be preferably formed.

[0031] (3) Formation of the copper layer A copper layer 16 is formed on the peeling layer 14. For example, the copper layer 16 may be formed by a wet film formation method such as electroless copper plating and electrolytic copper plating, a dry film formation method such as sputtering and chemical vapor deposition, or a combination thereof. Preferably, the copper layer 16 is formed by electrolytic copper plating. In particular, from the viewpoint of controlling the initial deposition of the copper layer 16 and reducing the crystallite size, it is preferable to set the conditions for electrolytic foil manufacturing of the copper layer 16 as follows. Specifically, a sulfuric acid-based copper electrolyte is used, with a copper concentration of 40 g / L to 80 g / L (more preferably 50 g / L to 70 g / L, even more preferably 60 g / L to 70 g / L), a free sulfuric acid concentration of 80 g / L to 120 g / L (more preferably 80 g / L to 110 g / L, even more preferably 90 g / L to 110 g / L), and a carboxybenzotriazole (CBTA) additive concentration of 60 ppm to 400 ppm (more preferably 80 ppm to 400 ppm, even more preferably 80 ppm to 200 ppm). A DSA (dimensionally stable anode) is used as the anode, with a liquid temperature of 20°C to 60°C (more preferably 40°C to 60°C, even more preferably 40°C to 50°C), and a current density of 30 A / dm². ２ 70A / dm or more ２ Less than or equal to (more preferably 30 A / dm ２ Above 60 A / dm ２ More preferably, 30 A / dm ２ 50A / dm or more ２ By electrolysis as described below, the desired electrolytic copper foil can be preferably obtained. By adding carboxybenzotriazole (CBTA) as an additive to the electrolyte and controlling the current density etc. within the above range during electrolytic foil manufacturing, it becomes easier to form the copper layer 16 having the predetermined C concentration.

[0032] If desired, the surface of the copper layer 16 may be subjected to a roughening treatment, a rust-preventive treatment, and / or a silane coupling agent treatment to form a roughened layer, a rust-preventive treatment layer, and / or a silane coupling agent layer consisting of a plurality of roughened particles. These treatments are as described above.

[0033] (4) Formation of adhesive layer (optional step) If desired, an adhesive layer 18 is formed on the surface of the copper layer 16 opposite to the release layer 14. The method for forming the adhesive layer 18 is not particularly limited, but it can preferably be done by, for example, applying a known adhesive for hot stamping to a part or all (preferably all) of the surface of the copper layer 16 and drying it.

[0034] The transfer laminate 10 of this disclosure is preferably used to manufacture articles having wiring, i.e., wiring bodies. That is, according to a preferred embodiment of this disclosure, a wiring body including a circuit formed using the transfer laminate 10 is provided. The wiring body according to this embodiment includes a layered structure in which a transfer target and a circuit derived from a copper layer 16 are laminated. By forming a circuit by transfer using the transfer laminate 10, it is possible to reduce the number of steps and reduce the environmental burden by not using chemicals (e.g., etching solutions). To explain the chemicals in more detail, in conventional wiring formation including wet processes such as subtractive and additive methods, various chemicals such as cleaning solutions, etching solutions, plating solutions, and surface treatment chemicals are used in each step, and cleaning wastewater for removing the above chemicals is also discharged. As a result, a large amount of wastewater is generated, which has a significant environmental burden. This problem is conveniently solved by using the transfer laminate 10 of this disclosure. A preferred method for manufacturing wiring bodies will be described later.

[0035] Examples of materials to be transferred to the wiring body include resin, paper, nonwoven fabric, cloth, wood, leather, metal, glass, and composites of these. The shape of the material to be transferred may be film-like, sheet-like, or plate-like, but is not limited to these shapes, and may be a three-dimensionally curved or deformed structure. Specific examples of materials to be transferred include resin substrates, resin molded products, housings, windows, tags, furniture, building materials, wooden goods, clothing, wearable devices, bags, wallets, shoes, belts, etc. With the transfer laminate 10 of this disclosure, since patterning can be directly applied to these materials, an advantage over conventional wet process wiring board formation methods is that circuits can be formed on various types of substrates.

[0036] Examples of applications of wiring structures using the transfer laminate 10 of this disclosure include printed circuit boards, flexible printed circuit boards, COF, TAB tape, RFID, antennas, heating wires, sensors, etc. Preferred examples of resins that form the resin substrate or resin molded product of these wiring structures include polyethylene terephthalate, polyethylene naphthalate, polyvinyl fluoride, polyvinylidene fluoride, rigid polyvinyl chloride, polyvinylidene chloride, nylon, polyimide, polyamide, polystyrene, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polycarbonate, polyacrylonitrile, polybutene, flexible polyvinyl chloride, polyethylene, polypropylene, polyurethane, ethylene vinyl acetate copolymer, polyvinyl acetate, liquid crystal polymer, polyether ether ketone, polytetrafluoroethylene, etc.

[0037] The wiring is preferably in the form of a plate (i.e., a wiring board), and particularly preferably a printed circuit board. The printed circuit board has a layered structure in which a resin layer and a circuit derived from the copper layer 16 are laminated in that order. The resin layer included in the printed circuit board may include the resins exemplified above for the resin substrate or resin molded product, and / or insulating curable resins. Furthermore, the resin layer is preferably a prepreg and / or a resin sheet. A prepreg is a general term for a composite material obtained by impregnating a substrate such as a synthetic resin plate, glass plate, glass woven fabric, glass nonwoven fabric, or paper with an insulating curable resin. Preferred examples of insulating curable resins include epoxy resin, cyanate resin, bismaleimide triazine resin (BT resin), polyphenylene ether resin, and phenolic resin. Examples of insulating curable resins that constitute a resin sheet include insulating resins such as epoxy resin, polyimide resin, and polyester resin. Furthermore, the resin layer may contain filler particles made of various inorganic particles such as silica and alumina from the viewpoint of improving insulation. The thickness of the resin layer is not particularly limited, but is preferably 1 μm to 1000 μm, more preferably 2 μm to 400 μm, and even more preferably 3 μm to 200 μm. The resin layer may be composed of multiple layers.

[0038] Specific examples of printed circuit boards include single-sided or double-sided printed circuit boards in which the copper layer 16 of this disclosure is transferred to one or both sides of a prepreg in the shape of a predetermined circuit pattern, and multilayer printed circuit boards made by layering these. Other specific examples include flexible printed circuit boards, COFs, TAB tapes, RFIDs, antennas, heating wires, etc., in which the copper layer 16 of this disclosure is transferred to the aforementioned resin layer or paper in the shape of a predetermined circuit pattern. The transfer laminate 10 of this disclosure can also be preferably used in manufacturing methods using a coreless build-up method in which insulating resin layers and conductive layers are alternately laminated without using a so-called core substrate.

[0039] Manufacturing Method for Wiring The transfer laminate 10 of this disclosure is preferably used for manufacturing wiring, as described above. That is, according to a preferred embodiment of this disclosure, a method for manufacturing wiring (particularly preferably a wiring board) using the transfer laminate 10 is provided. This method for manufacturing wiring preferably includes circuit formation by a hot stamping method. The hot stamping may be hot stamping using a relief plate 22 (relief plate hot stamping), as described above with reference to Figure 2, or it may be digital hot stamping without using a relief plate. Below, examples of manufacturing methods for wiring by relief plate hot stamping and digital hot stamping will be described separately. As will be described later, the manufacturing of wiring by relief plate hot stamping may be carried out using a transfer laminate 10 having an adhesive layer 18, or using a transfer laminate 10 without an adhesive layer 18.

[0040] (a) Method for manufacturing wiring by relief hot stamping (with adhesive layer) In the method for manufacturing wiring by relief hot stamping, first, as shown in Figure 2(a), a transfer laminate 10 comprising a support 12, a release layer 14, a copper layer 16, and an adhesive layer 18 is laminated on the surface of the object to be transferred 20. This lamination is carried out so that the object to be transferred 20 and the adhesive layer 18 are in contact. The object to be transferred 20 can preferably be made of the resin layer or paper described above.

[0041] Next, as shown in Figure 2(b), a heating and pressing treatment is performed on the support 12 side of the transfer laminate 10 laminated on the transfer target 20 using a plate (relief plate 22) having a circuit pattern-shaped convex surface. In this way, the heat from the relief plate 22 is transferred to the adhesive layer 18 via the support 12, the release layer 14, and the copper layer 16. At this time, the part of the adhesive layer 18 to which heat is transferred (heat transfer part 18a) is the part of the relief plate 22 that corresponds to the circuit pattern (the part directly below the circuit pattern). Then, the adhesive layer 18 and the transfer target 20 are bonded at the heat transfer part 18a. In this way, the adhesive layer 18 corresponding to the circuit pattern can be bonded to the transfer target 20. The relief plate 22 may be a known relief plate for hot stamping and is not particularly limited. The circuit pattern of the relief plate 22 may be appropriately determined according to the shape of the circuit to be formed. Furthermore, the heating and pressing treatment can be performed, for example, using a commercially available hot stamping device. In this case, the hot stamping apparatus can appropriately set conditions (for example, temperature and time) that enable adhesion between the adhesive layer 18 and the object to be transferred 20, depending on the type of adhesive layer 18 (material of the adhesive, etc.).

[0042] Subsequently, as shown in Figure 2(c), the transfer laminate 10 after the heat and pressure treatment is peeled off from the object to be transferred 20. In this way, the copper layer 16 can be transferred to the surface of the object to be transferred 20 in a circuit pattern via the adhesive layer 18. That is, only the heat transfer portion 18a of the adhesive layer and the portion of the copper layer 16 that is in contact with the heat transfer portion 18a remain on the surface of the object to be transferred 20, and the remaining portion (unreacted portion) is peeled off from the object to be transferred 20 together with the support 12. In this way, the copper layer 16 can be cut out in a predetermined pattern, and a circuit can be easily formed. Therefore, in circuit formation according to this embodiment, the number of steps is greatly reduced compared to conventional circuit formation methods such as the subtractive method and additive method, and the environmental burden can be greatly reduced because no chemicals are used at all.

[0043] (b) Method for manufacturing wiring by relief hot stamping (without adhesive layer) As described above, in the method for manufacturing wiring by relief hot stamping, a transfer laminate 10 without an adhesive layer 18 can also be used. In this manufacturing method, first, a transfer laminate 10 comprising a support 12, a release layer 14, and a copper layer 16 is laminated onto the surface of the object to be transferred 20. This lamination is carried out so that the object to be transferred 20 and the copper layer 16 are in contact. It is preferable to use the resin described above as the object to be transferred 20. This is for bonding with the copper layer 16 by thermal melting of the resin, which will be described later. From this viewpoint, it is preferable that the object to be transferred 20 contains a resin, and more preferably contains a resin substrate or a resin molded product. In particular, it is preferable that the object to be transferred 20 contains a resin that melts when heated (i.e., a thermoplastic resin). The melting point of the resin contained in the object to be transferred 20 is preferably 100°C or more and 350°C or less, more preferably 120°C or more and 340°C or less, and even more preferably 130°C or more and 300°C or less. Furthermore, the transfer target 20 only needs to have at least one surface in contact with the copper layer 16 made of resin, and may be a single layer of resin or a composite of a resin layer and a non-resin layer (a layer made of paper, metal, glass, etc.).

[0044] Next, a heating and pressing treatment is performed on the side of the transfer laminate 10 stacked on the object to be transferred 20 that faces the support 12, using a plate (relief plate 22) having a convex surface in the shape of a circuit pattern. In this way, the heat from the relief plate 22 is transferred to the object to be transferred 20 via the support 12, the release layer 14, and the copper layer 16. At this time, the part of the object to be transferred 20 that receives heat (heat transfer part) is the part of the relief plate 22 that corresponds to the circuit pattern (the part directly below the circuit pattern). Then, the copper layer 16 and the object to be transferred 20 are melt-bonded in the heat transfer part. In this way, the copper layer 16 corresponding to the circuit pattern can be directly attached to the object to be transferred 20. The relief plate 22 may be any known relief plate for hot stamping and is not particularly limited. The circuit pattern of the relief plate 22 can be appropriately determined according to the shape of the circuit to be formed. The heating and pressing treatment can be performed, for example, using a commercially available hot stamping device. In this case, the hot stamping apparatus should appropriately set conditions (e.g., temperature and time) that enable melt-bonding of the copper layer 16 and the transfer object 20, depending on the type of transfer object 20 (melting point, softening point of the resin layer). Preferably, as described above, the transfer object 20 includes a resin film, and the heating temperature in the heat-pressure treatment is above the melting point of the resin constituting the resin film. For example, the heating temperature is preferably 100°C to 400°C, more preferably 130°C to 380°C, and even more preferably 140°C to 350°C. When the heating temperature becomes high (e.g., 200°C or higher) depending on the type of transfer object 20, it is preferable that the support 12 be made of metal to prevent distortion or displacement due to heating and pressurizing. Copper is preferred as the metal constituting the support 12.

[0045] The transfer laminate 10, after heat and pressure treatment, is peeled off from the object to be transferred 20. This allows the copper layer 16 to be directly transferred to the surface of the object to be transferred 20 in a circuit pattern. That is, only the heat transfer portion of the copper layer 16 remains on the surface of the object to be transferred 20, and the remaining portion is peeled off from the object to be transferred 20 together with the support 12. In this way, the copper layer 16 can be cut out in a predetermined pattern, and circuits can be easily formed. Therefore, even in circuit formation according to this embodiment, the number of steps is greatly reduced compared to conventional circuit formation methods such as the subtractive method and additive method, and the environmental burden can be greatly reduced because no chemicals are used at all. Furthermore, in this embodiment, since the wiring body does not have an adhesive layer, thinning can be achieved, and in addition, since the transfer laminate 10 does not have adhesive attached, copper recycling can be easily performed.

[0046] (c) Method for manufacturing wiring by digital hot stamping In the method for manufacturing wiring by digital hot stamping, first, a circuit pattern-shaped adhesive layer 18 is laminated onto the surface of the transfer target 20. The lamination of the adhesive layer 18 onto the transfer target 20 is preferably done by printing. This printing is preferably done by a laser printer, inkjet printer, screen printing, or a combination thereof, and more preferably by a laser printer. An example of printing with a laser printer is to use a toner in which graphite or pigment is optionally attached to an adhesive such as an acrylic resin, and this toner is melted by heat and printed onto the transfer target 20. In any case, by using commercially available printing equipment, the adhesive layer 18 can be printed on the transfer target 20 in the desired pattern easily and accurately.

[0047] Next, the transfer laminate 10 is laminated onto the surface of the transfer target 20 on which the adhesive layer 18 is laminated, such that the copper layer 16 and the adhesive layer 18 are in contact. The method of laminating the transfer laminate 10 onto the transfer target 20 is not particularly limited, but it can preferably be done by roll lamination, for example.

[0048] Next, the side of the transfer laminate 10 laminated onto the object to be transferred 20 that is facing the support 12 is subjected to a heat and pressure treatment. This allows the copper layer 16 and the object to be transferred 20 to be bonded to the adhesive layer 18. The heat and pressure treatment can preferably be performed by hot roll lamination using a commercially available dry coater, for example. Alternatively, the heat and pressure treatment can be performed simultaneously with or in parallel with the lamination of the transfer laminate 10 onto the object to be transferred 20 by using a pair of rollers to sandwich the transfer laminate 10 and the object to be transferred 20 and performing hot roll lamination. In this case, the heating temperature of the rollers, the distance between the rollers, the roll speed, etc., should be appropriately adjusted according to the type of adhesive layer 18 (material of the adhesive, etc.) so that conditions are met for adhesion between the adhesive layer 18, the copper layer 16, and the object to be transferred 20.

[0049] The transfer laminate 10, after heat and pressure treatment, is peeled off from the transfer target 20. In this way, the copper layer 16 can be transferred to the surface of the transfer target 20 in a circuit pattern via the adhesive layer 18. That is, only the portion of the copper layer 16 in contact with the adhesive layer 18 remains on the surface of the transfer target 20, and the remaining portion is peeled off from the transfer target 20 together with the support 12. In this way, the copper layer 16 can be die-cut into a predetermined pattern, and a circuit can be easily formed. Therefore, even in circuit formation according to this embodiment, the number of steps is greatly reduced compared to conventional circuit formation methods such as the subtractive method and the additive method, and the environmental burden can be greatly reduced because no chemicals are used at all. Moreover, since no adhesive is attached to the copper layer 16 peeled off from the transfer target 20, it is possible to easily recycle the copper.

[0050] The present invention will be further described in detail by the following examples. However, the present invention is not limited to the following examples.

[0051] Examples 1-6: The transfer laminate 10 was prepared and evaluated as follows.

[0052] (1) Preparation of the support A copper electrolyte with the composition shown below, a cathode, and a DSA (dimensionally stable anode) as the anode are used, with a solution temperature of 50°C and a current density of 70 A / dm ２Electrolysis was performed to obtain an electrolytic copper foil with a thickness of 9 μm as the support 12. At this time, an electrode whose surface roughness was adjusted by polishing the surface with a #1000 grit buff was used as the cathode. <Composition of copper electrolyte> - Copper concentration: 80 g / L - Sulfuric acid concentration: 300 g / L - Chlorine concentration: 30 mg / L - Glue concentration: 5 mg / L

[0053] (2) Formation of the peeling layer The electrode surface of the acid-washed support was immersed for 15 seconds at a liquid temperature of 30°C in an aqueous CBTA solution with the carboxybenzotriazole (CBTA) concentration, free sulfuric acid concentration, and copper concentration shown in Table 1, and the CBTA component was adsorbed onto the electrode surface of the support. In this way, a CBTA layer was formed on the electrode surface of the support as a peeling layer 14.

[0054] (3) Formation of auxiliary metal layer The support 12 on which the peeling layer 14 is formed is immersed in a solution containing nickel with a nickel concentration of 20 g / L, prepared using nickel sulfate, at a liquid temperature of 30°C, pH 3, and current density of 1.3 A / dm ２ Under these conditions, nickel equivalent to a thickness of 0.001 μm was deposited onto the release layer 14. In this way, a nickel layer was formed on the release layer 14 as an auxiliary metal layer.

[0055] (4) The support 12 on which the auxiliary metal layer for copper layer formation is formed is immersed in a copper solution with the copper concentration, free sulfuric acid concentration, and CBTA concentration shown in Table 1, at a solution temperature of 45°C and a current density of 40 A / dm ２ Electrolysis was performed to form a copper layer 16 of the thickness shown in Table 1 on the auxiliary metal layer. In this way, a transfer laminate 10 was obtained.

[0056] (5) Silane coupling agent treatment A silane coupling agent treatment was performed by adsorbing an aqueous solution containing a commercially available silane coupling agent onto the copper layer 16 side surface of the transfer laminate 10 and evaporating the water using an electric heater.

[0057]

[0058] (6) Evaluation of the transfer laminate The transfer laminate 10 obtained in (5) above was evaluated as shown below.

[0059] <Crystallite Size> The copper layer 16 was measured and its crystallite size calculated by X-ray diffraction (XRD) as follows. First, XRD measurements were performed on the surface of the transfer laminate 10 on the copper layer 16 side. This measurement was performed using an X-ray diffractometer (Rigaku Corporation, RINT-TTRIIII, with a D / teX Ultra 250 HE detector (Rigaku Corporation)) under the following measurement conditions.

[0060] (Measurement conditions) - X-ray type: Cu Kα rays - Tube voltage: 50kV - Tube current: 300mA - Optical system: Focused method - Scan axis: 2θ / θ - Angle range: 2θ = 20 to 140° - Step size: 0.01° - Scan speed: 2° / min

[0061] The crystallite size was calculated from the diffraction peak of the (111) plane, which had the highest peak intensity, among the diffraction peaks of the (111), (200), (220), and (311) crystal planes of Cu obtained by XRD measurements. Specifically, the full width at half maximum of the (111) plane diffraction peak was first calculated by fitting with a segmented pseudo-Voigt function. In addition, LaB was used as a standard material to correct for the broadening of the diffraction peak width due to the instrument. ６ Width correction was performed by measuring [the specified value]. Then, the crystallite size was calculated using Scherrer's equation shown below: D = (K × λ) / (β × cosθ) (wherein D is the crystallite size (Å), K is Scherrer's constant, λ is the wavelength of the X-ray (Å), β is the full width at half maximum of the diffraction peak (rad), and θ is the Bragg angle (rad)), with Scherrer's constant K set to 0.94. The results are shown in Table 2.

[0062] <C concentration in the copper layer> The elemental analysis of the transfer laminate 10 was performed by glow discharge emission spectrometry (GD-OES), and the C concentration in the copper layer was calculated as follows. First, as a pretreatment, the side of the transfer laminate 10 facing the support 12 was attached to an aluminum plate with adhesive. Then, elemental analysis by GD-OES was performed while sputtering down in the depth direction from the copper layer 16 side of the transfer laminate 10 toward the support 12. This elemental analysis was performed using a glow discharge emission spectrometer (JOBIN YVON, JY-5000RF) under the following measurement conditions. (Measurement conditions) - Output: 30W - Gas pressure: 665Pa (Gas type: Ar) - Sputtering rate: 7μm / min (Cu equivalent) - Step (sec) / point: 0.02 (Measurement point interval; 1 point measured every 0.02 seconds) - Measurement mode: Normal mode High Dynamic Detection (HDD) measurement - Measured elements and orbitals: C, N, O, Cu, and S (Quantification was performed by calculating using a calibration curve from semi-quantitative data and intensity profile data) - N=3 measurement

[0063] Based on the depth profile of the obtained C concentration (mass%), three tangent lines L are defined according to the definition and procedure described above. １ , L ２ and L ３ Pull, L １ and L ２ Intersection X １ , and L ２ and L ３ Intersection X ２ We found the two intersection points X １ and X ２ The carbon concentration of the copper layer 16 was calculated by determining the midpoint and averaging the carbon concentrations at the sputtering depths corresponding to the midpoint. Three depth profile data points were obtained by changing the measurement position, and after calculating the carbon concentration for each point, the average of the three points was taken as the carbon concentration of the copper layer 16. The results are shown in Table 2. Note that the carbon concentration depth profile shown in Figure 4 was obtained in Example 1.

[0064] <Evaluation of Die-Cutting Performance> Hot Stamping Test The copper layer 16 was transferred to the transfer target 20 using the hot stamping method, and the die-cutting performance was evaluated. Specifically, first, a commercially available hot stamping adhesive was applied to the copper layer 16 side surface of the transfer laminate 10 to a thickness of approximately 1 μm and allowed to dry. A commercially available polyethylene terephthalate (PET) film with a thickness of 200 μm was prepared as the transfer target. A relief plate 22 having a pattern with two straight lines of 1.4 mm width and 10 mm length as unheated areas was set in a commercially available hot stamping device, and the PET film and transfer laminate 10 were placed on it in this order. At this time, the surface of the PET film and the adhesive applied to the transfer laminate 10 were made to be in contact. Hot stamping was then performed under conditions of 150°C and 0.1 seconds. After hot stamping, the copper layer 16 of the predetermined pattern was transferred onto the PET film by peeling off the untransferred parts of the support 12 and copper layer 16 from the PET film.

[0065] Overall Evaluation The surface of the PET film on the side where the copper layer 16 was transferred was observed using an optical microscope (VHX X-1, manufactured by Keyence Corporation) at a magnification of 20x (magnification sufficient to observe the entire pattern) with mixed illumination conditions. If there was no foil residue in areas other than the transferred portion of the copper layer 16, or if the ratio of the length of the foil residue to the pattern length was 5% or less, it was judged to be possible to die-cut without problems and was deemed acceptable. On the other hand, if the above ratio exceeded 5%, it was judged to be unacceptable as the die-cut was not in the desired shape. Since foil residue may occur due to variations in the peeling method of the support 12, a ratio of 5% or less was considered to be within the range of variation in the peeling method. The results are shown in Table 2. For reference, the optical microscope image of Example 2 is shown in Figure 5, and the optical microscope image of Example 6 is also shown in Figure 6.

[0066] Partial Evaluation: For cases where the overall evaluation was deemed satisfactory, the surface of the PET film on the side where the copper layer 16 was transferred was observed using a laser microscope (Keyence Corporation, VK-X100) at 50x magnification, no optical zoom, and in laser light mode. The position was adjusted so that the interface between the wiring pattern and the space was centered. This procedure was performed for five different fields of view, and it was checked whether holes or cracks (breaks) had occurred in the wiring in each field of view. The results are shown in Table 2. For reference, the laser microscope image of Example 1 is shown in Figure 7.

[0067] Overall Evaluation A comprehensive evaluation was conducted by combining the overall and partial evaluations, and a rating was assigned according to the following criteria. The results are shown in Table 2. - Rating A: Overall evaluation is satisfactory, and the number of fields of view with holes or cracks in the wiring in the partial evaluation is 1 or less (Excellent) - Rating B: Overall evaluation is satisfactory, and the number of fields of view with holes or cracks in the wiring in the partial evaluation is 2 or more (Usable) - Rating C: Overall evaluation is unsatisfactory (Not usable)

[0068] <Continuity Check> In the die-cutting performance evaluation described above, continuity was checked for the wiring transferred onto the PET film. Specifically, the test leads of a digital multimeter (M-02FB, manufactured by Custom Co., Ltd.) were touched to both ends of the wiring to check the resistance value. Continuity was determined to be present if the resistance value was 5Ω or less. As a result of the measurements, continuity was determined to be present in all of Examples 1 to 6.

[0069]

[0070] 10: Transfer laminate, 12: Support, 14: Release layer, 16: Copper layer, 18: Adhesive layer, 18a: Heat transfer section, 20: Transfer target, 22: Relief printing plate

Claims

1. A transfer laminate comprising a support, a release layer, and a copper layer in this order, wherein the C concentration in the copper layer is 0.010% by mass or more when the copper layer is elementally analyzed by glow discharge emission spectrometry (GD-OES).

2. The transfer laminate according to claim 1, wherein the product of the C concentration (mass%) of the copper layer and the thickness (μm) of the copper layer is 0.005 mass%·μm or more and 1.650 mass%·μm or less.

3. The transfer laminate according to claim 1 or 2, wherein the copper layer has a thickness of 0.1 μm or more and 10 μm or less.

4. The transfer laminate according to claim 1 or 2, wherein the support is a copper foil with a thickness of 7 μm or more and 18 μm or less.

5. The transfer laminate according to claim 1 or 2, further comprising an adhesive layer on the side of the copper layer opposite to the release layer.

6. A wiring body including a circuit formed using the transfer laminate described in claim 1 or 2.

7. A method for manufacturing a wiring harness, comprising: a step of laminating a transfer laminate according to claim 5 onto the surface of a transfer object such that the adhesive layer and the transfer object are in contact; a step of applying heat and pressure to the support-side surface of the transfer laminate laminated onto the transfer object using a plate having a circuit pattern-shaped convex surface, thereby adhering the adhesive layer corresponding to the circuit pattern to the transfer object; and a step of peeling the transfer laminate from the transfer object after the heat and pressure treatment, thereby transferring the copper layer to the surface of the transfer object in the circuit pattern shape via the adhesive layer.

8. A method for manufacturing a wiring harness, comprising: a step of laminating a transfer laminate according to claim 1 or 2 onto the surface of a transfer object such that the copper layer and the transfer object are in contact; a step of applying heat and pressure treatment to the support-side surface of the transfer laminate laminated onto the transfer object using a plate having a circuit pattern-shaped convex surface, thereby directly adhering the copper layer corresponding to the circuit pattern to the transfer object; and a step of peeling the transfer laminate from the transfer object after the heat and pressure treatment, thereby transferring the copper layer to the surface of the transfer object in the shape of the circuit pattern.

9. The method for manufacturing a wiring harness according to claim 8, wherein the material to be transferred contains a resin having a melting point of 100°C or more and 350°C or less.

10. The method for manufacturing a wiring harness according to claim 9, wherein the heating temperature in the heating and pressurizing treatment is 100°C or more and 400°C or less, and the heating temperature is equal to or greater than the melting point of the material to be transferred.

11. A method for manufacturing a wiring harness, comprising: a step of laminating an adhesive layer in the shape of a circuit pattern on the surface of a material to be transferred; a step of laminating a transfer laminate according to claim 1 or 2 on the surface of the material to be transferred on which the adhesive layer is laminated, such that the copper layer and the adhesive layer are in contact; a step of applying heat and pressure treatment to the support-side surface of the transfer laminate laminated on the material to be transferred, thereby bonding the copper layer and the material to be transferred to the adhesive layer; and a step of peeling the transfer laminate from the material to be transferred after the heat and pressure treatment, thereby transferring the copper layer in the shape of a circuit pattern to the surface of the material to be transferred via the adhesive layer.

12. The method for manufacturing a wiring harness according to claim 11, wherein the lamination of the adhesive layer onto the transfer object is performed by printing using at least one selected from the group consisting of a laser printer, an inkjet printer, and screen printing.

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