Laminate

Abstract

A purpose of the present invention is to provide, in an embodiment, a laminate that has both good conductivity and good adhesion (in particular, inhibition of delamination and / or in-layer cohesive failure of the laminate). A purpose of the present invention is to provide, in an embodiment, a laminate production method for producing such a laminate. In an embodiment, provided is a laminate comprising a metal layer, a metal-containing polymer layer, and a polymer layer in the stated order. The metal layer and the metal-containing polymer layer contain the same type of metal, the thickness of the metal layer is 0.1-1010 μm, and the thickness of the metal-containing polymer layer is 0.04-10 μm.

Description

Laminate

[0001] The present invention relates to a laminate, and more particularly to a laminate including a metal layer and a polymer layer.

[0002] Laminates having conductive wiring on a substrate, for example, laminates including a metal layer (wiring) and a polymer layer (substrate), have been used as various electronic components such as circuit boards. Generally, circuit boards can be manufactured through a process of applying a photoresist to a substrate having a metal foil, exposing and developing the photoresist to obtain a desired circuit pattern, and removing the metal foil in the area not covered with the photoresist by chemical etching to form a pattern.

[0003] Patent Document 1 discloses a method for forming a conductive film having a predetermined pattern on a substrate. In this method, a metal film containing metal particles is formed on the substrate by a droplet discharge method so as to have a pattern substantially identical to that of the conductive film, and then electroless plating is performed at least once to form a plating film that covers the surface of the metal film, thereby obtaining the conductive film.

[0004] Japanese Patent Application Laid-Open No. 2006-128228

[0005] However, the method described in Patent Document 1 leaves room for improvement in terms of achieving both the conductivity of the conductive film and the adhesion (particularly, suppressing interlayer delamination and / or intralayer cohesive failure of the laminate). Techniques for improving the conductivity of the conductive film include reducing the content of organic matter in the conductive film and forming a plating film on the conductive film. However, these techniques may result in a decrease in adhesion. In other words, conventionally, there has been a trade-off between the conductivity and adhesion of the conductive film.

[0006] Therefore, an object of one aspect of the present invention is to provide a laminate that achieves both good electrical conductivity and good adhesion (particularly, suppression of interlayer delamination and / or intralayer cohesive failure of the laminate), and to provide a method for producing such a laminate.

[0007] The present disclosure includes the following items. [1] A laminate comprising a metal layer, a metal-containing polymer layer, and a polymer layer, arranged in this order, wherein the metal layer and the metal-containing polymer layer contain the same metal, the metal layer has a thickness of 0.1 μm to 1010 μm, and the metal-containing polymer layer has a thickness of 0.04 μm to 10 μm. [2] A laminate comprising a metal layer, a metal-containing polymer layer, and a polymer layer, arranged in this order, wherein the metal layer and the metal-containing polymer layer contain the same metal, the polymer constituting the metal-containing polymer layer and the polymer constituting the polymer layer are nitrogen-containing polymers, and the metal-containing polymer layer contains a metal chemically bonded to a nitrogen atom. [3] The laminate according to item 1 or 2, wherein the metal-containing polymer layer contains a metal in an amount of 1 atomic % to 20 atomic %. [4] The laminate according to any one of items 1 to 3, wherein the polymer layer has a thickness of 1 μm or more and 1000 μm or less. [5] The laminate according to any one of items 1 to 4, wherein the metal layer comprises a first metal layer and a second metal layer disposed between the first metal layer and the metal-containing polymer layer, the first metal layer, the second metal layer, and the metal-containing polymer layer contain the same metal, the thickness of the first metal layer is 0.1 μm or more and 1000 μm or less, and the thickness of the second metal layer is 0.01 μm or more and 10 μm or less. [6] The laminate according to item 5, wherein the second metal layer is a layer formed by reducing a layer containing copper oxide. [7] The laminate according to any one of items 1 to 6, wherein the metal layer contains carbon. [8] The laminate according to item 7, wherein the metal layer contains carbon at 0.1 atomic % or more and 15 atomic % or less. [9] The laminate according to any one of items 1 to 8, wherein the metal layer and the metal-containing polymer layer contain copper.

[10] The laminate according to any one of items 1 to 9, wherein a pattern of the metal layer is formed on the metal-containing polymer layer.

[11] The laminate according to any one of items 1 to 10, wherein the metal-containing polymer layer contains sodium.

[12] The laminate according to item 11, wherein the metal-containing polymer layer contains sodium in an amount of 0.1 atomic % to 10 atomic %.

[13] The laminate according to any one of items 1 to 12, wherein the polymer constituting the metal-containing polymer layer and the polymer constituting the polymer layer are nitrogen-containing polymers, and the metal-containing polymer layer contains a metal chemically bonded to a nitrogen atom.

[14] The laminate according to any one of items 1 to 13, wherein the metal-containing polymer layer contains a zero-valent and / or monovalent metal.

[15] The laminate according to item 14, wherein the metal-containing polymer layer contains a zero-valent and / or monovalent metal but does not contain a divalent metal.

[16] The laminate according to item 14 or 15, wherein the metal-containing polymer layer contains a zero-valent and monovalent metal.

[17] The laminate according to any one of items 1 to 16, wherein the metal concentration at a position 20 nm toward the metal layer from the boundary between the metal-containing polymer layer and the polymer layer is 1.0 atomic % or more and 5.0 atomic % or less.

[18] The laminate according to any one of items 1 to 17, wherein X-ray photoelectron spectroscopy of the metal-containing polymer layer exhibits a peak in the range of 571 eV to 574 eV.

[19] The laminate according to any one of items 1 to 18, wherein the metal layer has a porosity of 0.1 vol % to 30 vol % in a region of 1 nm to 500 nm deep from the metal-containing polymer layer side.

[20] The laminate according to any one of items 1 to 19, wherein the metal layer contains cuprous oxide.

[21] The laminate according to any one of items 1 to 20, wherein, in observation of a cross section in the thickness direction, the ratio (L2) / (L1) of the length (L2) of the boundary line between the metal layer and the metal-containing polymer layer to the in-plane length (L1) of the laminate is 1.0 to 2.2.

[22] The laminate according to any one of items 1 to 21, wherein the metal-containing polymer layer is a metal-containing polyimide layer, and the polymer layer is a polyimide layer.

[23] The laminate according to any one of items 1 to 22, wherein, in infrared absorption spectroscopy, the minimum value of the ratio (IR1) / (IR2) of the peak intensity (IR1) of a first peak derived from a first structure in a main chain to the peak intensity (IR2) of a second peak derived from a second structure in the main chain of the metal-containing polymer layer and the polymer constituting the polymer layer is 0.2 or more and 1.5 or less.

[24] The laminate according to any one of items 1 to 23, which is used as a component of an electronic circuit board.

[25] A method for producing the laminate according to any one of items 1 to 24, comprising: a coating step of coating a metal oxide on a polymer substrate; and a reduction step of reducing the metal oxide.

[26] The method according to item 25, wherein the reduction is carried out by laser light irradiation.

[27] The method according to item 25 or 26, further comprising an electroless metal plating step.

[28] The method according to item 27, wherein the electroless metal plating step is carried out after the reduction step.

[29] A method for producing a laminate, comprising the steps of: forming a first metal layer having a thickness of 0.1 μm or more and 1000 μm or less; forming a second metal layer having a thickness of 0.01 μm or more and 10 μm or less; forming a metal-containing polymer layer having a thickness of 0.04 μm or more and 10 μm or less; and forming a polymer layer having a thickness of 1.0 μm or more and 1000 μm or less, wherein the first metal layer, the second metal layer, the metal-containing polymer layer, and the polymer layer are arranged in this order, and the first metal layer, the second metal layer, and the metal-containing polymer layer contain the same type of metal.

[30] The method for producing a laminate according to Item 29, wherein the step of forming the second metal layer comprises: a coating step of applying a dispersion containing metal particles and / or metal oxide particles onto a substrate to form a dispersion layer; a drying step of drying the dispersion layer to form a dry coating film on the substrate; and a step of heating the dry coating film to form the second metal layer.

[31] The method for producing a laminate according to Item 29, wherein the step of forming the second metal layer comprises: a coating step of applying a dispersion containing metal particles and / or metal oxide particles onto a substrate to form a dispersion layer, a drying step of drying the dispersion layer to form a dry coating film on the substrate, and a step of irradiating with a laser to bake the dry coating film to form the second metal layer.

[32] The method for producing a laminate according to Item 30 or 31, wherein the metal particles and / or metal oxide particles are copper particles and / or copper oxide particles.

[33] The method for producing a laminate according to any one of items 29 to 32, wherein the step of forming the first metal layer comprises a step of forming the first metal layer by immersing the second metal layer in a plating solution.

[34] The method for producing a laminate according to item 33, wherein the plating solution has a pH of 10 or more and 14 or less.

[0008] According to one aspect of the present invention, it is possible to provide a laminate that achieves both good electrical conductivity and good adhesion (particularly, suppression of interlayer delamination and / or intralayer cohesive failure of the laminate). Also, according to another aspect of the present invention, it is possible to provide a method for producing such a laminate.

[0009] It is a schematic diagram for explaining how to obtain the ratio (L2) / (L1). It is a diagram showing an example of the configuration of a laminate of the present embodiment. It is a diagram showing an example of the configuration of a laminate of the present embodiment. It is a schematic diagram of a metal wiring manufacturing apparatus that can be used in the present embodiment.

[0010] Hereinafter, exemplary embodiments of the present invention (hereinafter also referred to as the present embodiment) will be described with reference to the drawings. The present invention is not limited to the present embodiment, and various modifications can be made within the scope of the present invention.

[0011] In this specification, various measurements are performed based on the methods described in the specification, particularly the methods described in the Examples. In this specification, the upper or lower limit of a stepwise numerical range may be replaced with the upper or lower limit of a corresponding other stepwise numerical range, particularly the corresponding value described in the Examples. Furthermore, in this specification, the term "step" includes not only an independent step, but also a step that cannot be clearly distinguished from other steps, as long as the function of the step is achieved. The components (scale, shape, length, etc.) shown in the drawings may be exaggerated for clarity.

[0012] <Laminate> One aspect of the present invention provides a laminate including a metal layer, a metal-containing polymer layer, and a polymer layer in this order. In a typical aspect, the metal layer and the metal-containing polymer layer are in contact with each other, and the metal-containing polymer layer and the polymer layer are in contact with each other. In one aspect, the laminate is used as a component of an electronic circuit board. The laminate is suitably applied to, for example, a circuit board such as a printed wiring board. This type of circuit board generally has a structure in which conductive wiring is provided on a substrate. That is, in a laminate according to one aspect, a metal layer pattern is arranged on the substrate (more specifically, on the metal-containing polymer layer of a substrate having a polymer layer and a metal-containing polymer layer). Multiple metal layer patterns may be arranged on the substrate, and the shape and size thereof can be selected as desired.

[0013] In a laminate according to one embodiment, the metal layer and the metal-containing polymer layer contain the same type of metal. In the laminate according to one embodiment, the thickness of the metal layer is 0.1 μm or more and 1010 μm or less, or 0.1 μm or more and 1000 μm or less. In the laminate according to one embodiment, the thickness of the metal-containing polymer layer is 0.04 μm or more and 10 μm or less. In the laminate according to one embodiment, the thickness of the polymer layer is 1 μm or more and 1000 μm or less. In observation of a cross section in the thickness direction of the laminate according to one embodiment, the ratio (L2) / (L1) of the length (L2) of the boundary line between the metal layer and the metal-containing polymer layer to the in-plane length (L1) of the laminate is 1.0 or more and 2.2 or less.

[0014] In one embodiment, the metal layer includes a first metal layer and / or a second metal layer. In one embodiment, the metal layer includes a first metal layer and a second metal layer disposed between the first metal layer and the metal-containing polymer layer. In one embodiment, the first metal layer and the second metal layer are in contact with each other, and the second metal layer and the metal-containing polymer layer are in contact with each other. Furthermore, in a typical embodiment, the metal-containing polymer layer and the polymer layer are in contact with each other. In a laminate according to one embodiment, the first metal layer, the second metal layer, and the metal-containing polymer layer contain the same metal. In a laminate according to one embodiment, the thickness of the first metal layer is 0.1 μm or more and 1000 μm or less. In a laminate according to one embodiment, the thickness of the second metal layer is 0.01 μm or more and 10 μm or less. In a laminate according to one embodiment, the thickness of the metal-containing polymer layer is 0.04 μm or more and 10 μm or less. In a laminate according to one embodiment, the thickness of the polymer layer is 1 μm or more and 1000 μm or less. In one aspect, the laminate includes a first metal layer, the polymer of which may be partially modified during the formation process of the first metal layer, having a thickness of 0.1 μm to 1000 μm. Even in an aspect in which the first metal layer has a thickness of 0.1 μm to 1000 μm, this embodiment can achieve both good electrical conductivity and good adhesion (particularly, suppression of interlayer delamination and / or suppression of intralayer cohesive failure of the laminate).

[0015] One aspect of the present invention provides a laminate comprising a metal layer, a metal-containing polymer layer, and a polymer layer arranged in this order, wherein the metal layer and the metal-containing polymer layer contain the same type of metal, the thickness of the metal layer is 0.1 μm or more and 1010 μm or less, or 0.1 μm or more and 1000 μm or less, and the thickness of the metal-containing polymer layer is 0.04 μm or more and 10 μm or less.

[0016] Another aspect of the present invention provides a laminate comprising a metal layer, a metal-containing polymer layer, and a polymer layer arranged in this order, wherein the metal layer and the metal-containing polymer layer contain the same type of metal, the polymer constituting the metal-containing polymer layer and the polymer constituting the polymer layer are nitrogen-containing polymers, and the metal-containing polymer layer contains a metal chemically bonded to a nitrogen atom.

[0017] The morphology, thickness, and constituent elements of each layer can be identified by observing and analyzing a cross section of the laminate in the thickness direction using a scanning transmission electron microscope (STEM). Details of the identification method will be described in the Examples.

[0018] The metal layer can be formed by a method of applying a metal-containing dispersion, metal plating, sputtering, etc. The metal-containing polymer layer can be formed by a method of penetrating a metal into a portion of the polymer substrate (typically, a portion from the surface of the polymer substrate to a certain depth), etc. Therefore, the polymer substrate can have a metal-containing polymer layer and a polymer layer. This penetration may occur, for example, when forming the metal layer on the polymer substrate. In each of the metal layer and the metal-containing polymer layer, the metal may have a structure in which metal particles are fused to each other. In this case, the particle shape may not exist, i.e., all of the metal particles may be fused to each other. Alternatively, some of the metal may have a particle shape, and the other portions may be fused to each other. The fused material may extend across the metal layer and the metal-containing polymer layer.

[0019] The metal layer (in one embodiment, the first metal layer and the second metal layer) and the metal-containing polymer layer each contain one or more types of metal. In the present disclosure, unless otherwise specified, "metal" means a metal element belonging to Groups 3 to 16 of the periodic table of elements (in other words, a metal element other than an alkali metal element or an alkaline earth metal element). In one embodiment, the metal layer and the metal-containing polymer layer contain the same type of metal (i.e., the same element). The same type of metal may be one type or multiple types. At least one type of metal contained in the metal layer and the metal-containing polymer layer may be the same. For example, the metal species contained in the metal layer may be metal species α and metal species β, and the metal species contained in the metal-containing polymer layer may be metal species α and metal species γ. In this case, the metal species α is the "same type" metal of the present disclosure. Furthermore, for example, when a metal layer includes a first metal layer and a second metal layer, the first metal layer, the second metal layer, and the metal-containing polymer layer may each include a metal species α, and the second metal layer and the metal-containing polymer layer may further include a metal species β. In this case, the metal species α and β are the "same type" metals of the present disclosure. Also, for example, when a metal layer includes a first metal layer and a second metal layer, the metal species included in the first metal layer may be a metal species α and a metal species β, the metal species included in the second metal layer may be a metal species α and a metal species ω, and the metal species included in the metal-containing polymer layer may be a metal species α and a metal species γ. In this case, the metal species α is the "same type" metal of the present disclosure. The "same type" metal included in the metal layer and the metal-containing polymer layer preferably includes or is copper. The presence of the same type of metal contributes to good adhesion between the metal layer (particularly the second metal layer in an embodiment in which a first and second metal layer are present) and the metal-containing polymer layer due to an anchor effect. If the metals in the metal layer and the metal-containing polymer layer are all the same type (in an embodiment in which first and second metal layers are present, if the metals contained in the first metal layer, the second metal layer, and the metal-containing polymer layer are all the same type), there is also the advantage that adverse effects such as metal corrosion when different metals are present are less likely to occur.

[0020] The laminate of this embodiment can achieve both good electrical conductivity and good adhesion. One mechanism is believed to be as follows. Generally, during production, portions with weak mechanical strength (weak portions) may be formed on the surface of a polymer substrate (e.g., a polymer film). Furthermore, laser light, plating solution, etc., which may be used when forming a metal layer (particularly the first metal layer in an embodiment in which first and second metal layers are present) on the polymer substrate, can also cause partial modification (e.g., thermal decomposition or hydrolysis) of the polymer, resulting in the modified portion becoming a weak portion. In the weak portion, decomposition of the polymer main chain typically occurs. The ratio (IR1) / (IR2) of the present disclosure is an indicator of the degree of decomposition of the polymer main chain. The metal-containing polymer layer of this embodiment can be formed by infiltrating a metal into such a weak portion in a controlled manner. When a metal-containing polymer layer is present, the metal layer and the metal-containing polymer layer are likely to exhibit good adhesion due to the anchoring effect of the metal in the metal layer (particularly the second metal layer in an embodiment in which first and second metal layers are present) and the metal in the metal-containing polymer layer. In particular, when the metal layer and the metal-containing polymer layer contain the same type of metal, the interaction between these metals can produce a good anchoring effect. When the metal-containing polymer layer is formed by the penetration of the metal to a depth equal to or greater than the fragile portion, the anchoring effect is stronger. Additionally, the metal in the metal-containing polymer layer can act as a filler, contributing to improving the mechanical strength of the fragile portion. As a result, the metal-containing polymer layer tends to be less susceptible to cohesive failure even when the polymer is weakened. The above-described anchoring effect and cohesive failure suppression effect make it less likely for interlayer delamination and / or intralayer cohesive failure to occur in the region spanning the metal layer (in one embodiment, the first metal layer and the second metal layer), the metal-containing polymer layer, and the polymer layer. In this way, the laminate of this embodiment can exhibit good adhesion.

[0021] In a thickness direction cross-section observation of the laminate of this embodiment, the ratio (L2) / (L1) of the length (L2) of the boundary line between the metal layer and the metal-containing polymer layer to the in-plane length (L1) of the laminate is, in one aspect, 1.0 to 2.2, or 1.0 to 2.0. This ratio is an index of the roughness of the interface between the metal layer and the metal-containing polymer layer. A larger ratio is advantageous in terms of the anchoring effect between these layers. On the other hand, when the polymer in the metal-containing polymer layer is significantly weakened, this ratio tends to be larger. In one aspect, the ratio (L2) / (L1) is 1.0 or more, and in one aspect, it is greater than 1.0 or 1.05 or more, from the viewpoint of easily exhibiting good adhesion between the metal layer and the metal-containing polymer layer due to the anchoring effect. In another aspect, it is 2.2 or less, or 2.0 or less, or 1.8 or less, or 1.5 or less, or 1.3 or less, from the viewpoint of suppressing intralayer cohesive failure due to the metal-containing polymer layer having good mechanical strength. The ratio (L2) / (L1) is determined by observing a cross section of the laminate in the thickness direction using STEM. FIG. 1 is a schematic diagram illustrating how to determine the ratio (L2) / (L1). Note that in FIG. 1, the shape of the unevenness of the boundary surface is exaggerated and schematic. Referring to FIG. 1, the length of the boundary line between the metal layer ML and the metal-containing polymer layer MPL when traced freehand in the cross-sectional image is defined as the length of the boundary line (L2), and the length of the line segment P1-P2 connecting the intersection points P1 and P2 of the boundary line with both ends of the STEM image is defined as the in-plane length (L1) of the laminate, and the ratio (L2) / (L1) is calculated. Details of the measurement method are described in the Examples. The ratio (L2) / (L1) can be controlled by the type of polymer in the metal-containing polymer layer, the formation conditions of the metal layer (laser light irradiation conditions, plating conditions, etc.), etc. For example, by increasing the pulse output during laser light irradiation to moderately weaken the polymer, the metal can easily penetrate into the metal-containing polymer layer, increasing the ratio (L2) / (L1).

[0022] Each layer of the laminate will now be further described.

[0023] <Metal Layer> The metal layer may have one or more layers. Each layer contains one or more metals. As the metal, copper (Cu), silver (Ag), nickel (Ni), chromium (Cr), tin (Sn), zinc (Zn), and alloys containing these are preferred, with copper being more preferred. The metal layer is suitable, for example, as metal wiring in a substrate with metal wiring, such as a circuit board. The shape of the metal wiring in a planar view, i.e., the pattern, may have any shape, such as a linear, curved, circular, rectangular, or bent shape. In a preferred embodiment, the metal wiring is copper wiring.

[0024] The metal may exist as a metal compound, such as a metal oxide. For example, copper may exist as copper oxide (cuprous oxide, cupric oxide, and / or cuprous oxide). A suitable example of a metal constituting the metal layer is copper, particularly copper, which is a reduction product of copper oxide (also referred to as reduced copper in the present disclosure). A layer formed by reducing a layer containing copper oxide is referred to, for example, as a reduced copper layer. The reduced copper layer can be formed by reducing copper oxide, for example, by laser light irradiation or heat. In one embodiment, the laser light can be selectively irradiated (i.e., only the area where the reduced copper layer is desired to be formed). For example, in a coating film containing metal oxide particles, reduction of the metal oxide and fusion (i.e., integration) of the particles by sintering occur only in the area of ​​the coating film irradiated with laser light, thereby forming a reduced copper layer. When the metal layer (particularly the second metal layer in an embodiment in which first and second metal layers are present) includes or consists of a reduced copper layer, adhesion between the metal layer and the metal-containing polymer layer is likely to be excellent. In the reduced copper layer, a portion of the copper oxide may remain unreduced. The presence or absence of copper oxide (e.g., cuprous oxide) in the metal layer can be determined by X-ray diffraction (XRD) based on the presence or absence of a peak corresponding to copper oxide. Therefore, in one embodiment, the presence of copper oxide remaining in the reduced copper layer indicates that the zero-valent copper (i.e., present as a simple substance) in the reduced copper layer is reduced copper (i.e., the reduction product of copper oxide).

[0025] In a preferred embodiment, the metal layer (particularly the second metal layer in an embodiment in which first and second metal layers are present) contains cuprous oxide. Cuprous oxide can improve adhesion between the metal layer and the metal-containing polymer layer due to its high affinity with the polymer. In one embodiment, the upper surface of the metal layer (the first metal layer side in an embodiment in which first and second metal layers are present) has a structure in which particles containing reduced copper are fused together, and the lower surface (the second metal layer side in an embodiment in which first and second metal layers are present) can have a structure in which more copper oxide is contained than in the upper surface. In this case, the copper particles on the upper surface are likely to be strongly bonded to each other by the copper oxide, and the lower surface is likely to improve adhesion between the metal layer and the metal-containing polymer layer.

[0026] <Carbon> The metal layer (particularly the second metal layer in an embodiment in which a first and a second metal layer are present) preferably contains carbon. This facilitates improving the bending resistance of the metal layer, particularly the metal wiring. In particular, when copper particles are sintered (for example, when copper oxide particles are sintered by reducing them with laser light irradiation or heat), the presence of carbon can contribute to good sinterability. Therefore, it is particularly preferable that the metal layer contains copper (particularly reduced copper) and carbon. In one embodiment, the carbon may be derived from an organic substance contained in a dispersion containing metal particles, which will be described later. The carbon may be graphene, carbon nanotubes, a carbonized organic compound, or the like.

[0027] The amount of carbon contained in the metal layer (particularly the second metal layer in an embodiment in which first and second metal layers are present) is preferably 0.1 atomic % or more, or 1 atomic % or more, or 3 atomic % or more. The amount of carbon contained in the metal layer is preferably 15 atomic % or less, or 10 atomic % or less, or 7 atomic % or less, or 5 atomic % or less. Having the amount of carbon contained in the metal layer within the above range facilitates improving the bending resistance of the metal layer, particularly the metal wiring. Here, "atomic %" means "atomic percentage," i.e., the ratio of the number of atoms of a specific element (e.g., carbon in the above example) to the total number of atoms of the target object. Furthermore, the "amount of carbon contained in the metal layer" is measured within a range of 50 nm to 300 nm in the thickness direction of the metal layer from the interface between the metal layer and the metal-containing polymer layer. Note that when the thickness of the metal layer is thinner than 300 nm, the amount of carbon contained in the metal layer is interpreted as the amount of carbon contained in the entire metal layer. Furthermore, in an embodiment in which first and second metal layers are present, if the thickness of the second metal layer is less than 300 nm, even if the first metal layer contains carbon, the amount of carbon contained in this first metal layer is not included in the amount of carbon contained in the second metal layer.

[0028] The thickness of the metal layer (in an embodiment in which first and second metal layers are present, the total thickness of these) is, in one embodiment, 0.1 μm or more, or 0.5 μm or more, in terms of easily ensuring sufficient conductivity, and, in one embodiment, 1010 μm or less, or 1000 μm or less, or 500 μm or less, or 100 μm or less, or 50 μm or less, or 10 μm or less, or 5 μm or less, in terms of easily achieving excellent bending resistance. A thickness of not more than the above upper limit is also advantageous in terms of weight reduction, space saving, and flexibility when the laminate is used as, for example, a circuit board, an electronic device, etc.

[0029] In an embodiment in which a first and a second metal layer are present, the thickness of the first metal layer may be 0.1 μm or more and 1000 μm or less, and the thickness of the second metal layer may be 0.01 μm or more and 10 μm or less. The thickness of the metal layer is typically 0.11 μm or more. In one embodiment, the metal layer may consist only of the first metal layer and the second metal layer. When the metal layer consists only of the first metal layer and the second metal layer, the thickness of the metal layer may be 1010 μm or less.

[0030] In one embodiment, the metal layer has a first metal layer and / or a second metal layer. In one embodiment, the laminate has an arrangement of a polymer layer, a metal-containing polymer layer, a second metal layer, and a first metal layer in this order. In one embodiment, the first metal layer is a layer of the metal layer having a porosity of 0.5 vol% or less, and the second metal layer is a layer of the metal layer having a porosity of more than 0.5 vol%. The voids are regions where the constituent material (mainly metal) of the metal layer is very little or does not exist, and are typically voids surrounded by a continuous phase of the constituent material. In one embodiment, there are substantially no voids, or even if there are, there are very few voids on the upper surface side of the first metal layer (i.e., the surface opposite the polymer layer side). The method for measuring the porosity will be described in detail in the Examples.

[0031] 2A and 2B are diagrams showing an example of the configuration of a laminate when the metal layer has a first metal layer and a second metal layer, where Fig. 2A is a plan view and Fig. 2B is a cross-sectional view. Fig. 2B corresponds to the cross section of the dashed dotted line portion (A-A portion) in Fig. 2A, and therefore the arrow X direction, arrow Y direction, and arrow Z direction correspond to each other in Fig. 2A and Fig. 2B.

[0032] The laminate 1 comprises a first metal layer ML1, a second metal layer ML2, a metal-containing polymer layer MPL, and a polymer layer PL, in this order. In the drawing, the first metal layer ML1 and the second metal layer ML2 are collectively referred to as the "metal layer ML." Voids exist in the second metal layer. Voids are areas where the constituent material (mainly metal) of the metal layer is very little or absent, and are typically voids V surrounded by a continuous phase of the constituent material. In the first metal layer, there are essentially no voids, or even if they exist, they are in very small amounts. Therefore, for convenience, voids are illustrated in the second metal layer in the drawing, but this is not intended to limit the existence of voids to the second metal layer alone. In the figure, for convenience, the interface between the first metal layer ML1 and the second metal layer ML2, the boundary between the second metal layer ML2 and the metal-containing polymer layer MPL, and the interface between the metal-containing polymer layer MPL and the polymer layer PL are each shown by a virtual line (dotted line).

[0033] In the laminate, when the first metal layer side is considered to be the "upper side" and the polymer layer side is considered to be the "lower side," the upper surface of the first metal layer is open upward, the lower surface of the first metal layer and the upper surface of the second metal layer are in contact with each other, the lower surface of the second metal layer and the upper surface of the metal-containing polymer layer are in contact with each other, and the lower surface of the metal-containing polymer layer and the upper surface of the polymer layer are in contact with each other. Each of these surfaces may be flat, or may have irregularities as long as they are within the scope of the present invention.

[0034] The laminate 1 has a structure in which a wiring pattern (a first metal layer and a second metal layer) is formed on a polymer substrate (a metal-containing polymer layer and a polymer layer). In the figure, a plurality of metal layers are arranged in the Y direction, each extending in the X direction, but examples of the wiring pattern are not limited to the example shown in the figure.

[0035] In one embodiment, the pattern shapes of the second metal layer and the first metal layer correspond to each other, and in this case, the second metal layer is hidden in the shadow of the first metal layer in a plan view of the laminate 1.

[0036] <First Metal Layer> In one embodiment, the first metal layer may be disposed on the second metal layer. The first metal layer contributes to good electrical conductivity. In one embodiment, the constituent material of the first metal layer may fill some of the voids in the second metal layer and / or penetrate into the polymer substrate to form a metal-containing polymer layer. From the viewpoint of further improving electrical conductivity (further reducing resistance), a thicker first metal layer is often advantageous. Therefore, if further improving electrical conductivity (further reducing resistance) can be achieved when the first metal layer has a predetermined film thickness, it is presumed that further improving electrical conductivity (further reducing resistance) can also be achieved when the first metal layer has a thickness greater than that.

[0037] In one aspect, the thickness of the first metal layer may be 0.1 μm or more, or 0.5 μm or more, or 1.0 μm or more. This facilitates the flow of sufficient current when the first metal layer is used as wiring. The thickness of the first metal layer is preferably 1000 μm or less, or 999.99 μm or less, or 500 μm or less, or 100 μm or less, or 50 μm or less, or 10 μm or less, or 5 μm or less. This facilitates the first metal layer to have excellent bending resistance. The thickness of the first metal layer may be greater than the thickness of the second metal layer. This facilitates the production of a metal layer with excellent conductivity. From the same viewpoint, and also from the viewpoint of facilitating the thinning of the laminate, the thickness of the first metal layer may be 1.5 to 5.0 times the thickness of the second metal layer.

[0038] In one embodiment, the porosity of the first metal layer is 0.5 vol% or less, or 0.3 vol% or less. From the viewpoint of ease of forming the first metal layer, in one embodiment, the porosity may be 0.01 vol% or more, or 0.1 vol% or more. The porosity of the first metal layer can be controlled, for example, by adjusting a degreasing step before plating, and / or the plating temperature, and / or the plating time, and / or the composition of the plating solution, and / or the metal concentration (e.g., copper concentration) of the plating solution. It is also possible to control (e.g., reduce) the porosity of the formed second metal layer, for example, by adjusting plating conditions, performing a degreasing step before plating, etc.

[0039] <Second Metal Layer> The second metal layer can be disposed between the first metal layer and the metal-containing polymer layer (in one embodiment, a metal-containing polyimide layer). The thickness of the second metal layer is preferably 0.01 μm or more, or 0.05 μm or more, or 0.1 μm or more. This tends to improve plating growth when the first metal layer is formed by plating. The thickness of the second metal layer is preferably 10 μm or less, or 8 μm or less, or 5 μm or less, or 3 μm or less, or 1 μm or less. This tends to improve bending resistance of the metal layer.

[0040] The porosity of the second metal layer may be, for example, 30% by volume or less, or 28% by volume or less, or 20% by volume or less. This improves adhesion (particularly adhesion between the substrate and the metal layer), making chemical peeling less likely to occur. The oxidation stability of the metal layer is also likely to be excellent. In one embodiment, the porosity of the second metal layer is greater than 0.5% by volume. This makes it easier to relieve stress due to expansion of the metal (e.g., copper), and therefore easier to withstand thermal shock. The porosity may be 1% by volume or more, or 4% by volume or more.

[0041] The porosity of the second metal layer can be controlled, for example, by adjusting the output power, speed, and / or wavelength of the irradiating laser used in forming the metal layer. For example, the stronger the laser output and the slower the irradiation speed, the easier it is to reduce the porosity of the metal layer, while the weaker the laser output and the faster the irradiation speed, the easier it is to increase the porosity of the metal layer.

[0042] In one embodiment, the metal layer has a porosity of 0.1% to 30% by volume in a region from 1 nm to 500 nm deep from the metal-containing polymer layer side, i.e., in a region adjacent to the metal-containing polymer layer. The porosity is preferably 0.1% by volume or more, or 1% by volume or more, or 4% by volume or more, in order to easily relieve stress due to expansion of the metal (e.g., copper) and therefore to easily withstand thermal shock, and is preferably 30% by volume or less, or 28% by volume or less, or 20% by volume or less, in order to easily achieve excellent adhesion (especially adhesion between the metal layer and the metal-containing polymer layer), thereby making it difficult for the metal layer to peel off due to chemicals and improving the oxidation stability of the metal layer.

[0043] <Polymer layer and metal-containing polymer layer> The polymer layer and the metal-containing polymer layer function as a substrate (for example, a substrate of a circuit board, which is one embodiment of a laminate). The substrate constitutes a surface on which a wiring pattern, which is one embodiment of a metal layer, is arranged. The substrate is typically a plate or a film, but may also be a three-dimensional object having a desired three-dimensional shape. The plate is, for example, a support used in a circuit board such as a printed circuit board. The film is, for example, a base film used in a flexible printed circuit board. The three-dimensional object is, for example, a molded body used in various electronic components. When the substrate is a three-dimensional object, a metal-containing polymer layer and a polymer layer may be arranged on a surface portion of the substrate.

[0044] The polymer layer contains one or more polymers. The metal-containing polymer layer contains one or more metals and one or more polymers. The polymers contained in the metal-containing polymer layer and the polymer layer may be the same or different, but are preferably the same. Here, the term "same" means that the constituent monomer species of the polymers are the same. Examples of metals contained in the metal-containing polymer layer include the same metals as those in the metal layer, and copper (Cu), silver (Ag), nickel (Ni), chromium (Cr), tin (Sn), zinc (Zn), and alloys containing these are preferred, with copper being more preferred. The metal may be present as a metal compound.

[0045] In one embodiment, the metal-containing polymer layer is a region where the metal concentration is 1 atomic % or more, and the polymer layer is a region where the metal concentration is less than 1 atomic %. Using energy dispersive X-ray analysis (EDX analysis) by STEM, the metal species present in the metal-containing polymer layer and the metal species present in the polymer layer are identified, and the total metal amount of the identified metal species is measured, thereby determining the metal concentration of each layer. A more specific method for measuring the metal concentration will be described later.

[0046] In one embodiment, the thickness of the polymer layer is 1 μm or more, preferably 5 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more. This tends to result in excellent mechanical strength of the polymer layer. In one embodiment, the thickness of the polymer layer is 1000 μm or less, preferably 500 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less. This tends to result in excellent flexibility of the polymer layer. A polymer layer with excellent flexibility may be suitably used as a flexible printed circuit board. Having a thickness equal to or less than the above upper limit is advantageous in terms of weight reduction, space saving, and flexibility when using the laminate as, for example, a circuit board, an electronic device, etc.

[0047] In one embodiment, the thickness of the metal-containing polymer layer is 0.04 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and even more preferably 0.2 μm or more. This tends to result in excellent adhesion due to a good anchoring effect. In one embodiment, the thickness of the metal-containing polymer layer is 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less, even more preferably 1 μm or less, and particularly preferably 0.5 μm or less. This tends to result in excellent mechanical strength of the metal-containing polymer layer. Having a thickness equal to or less than the above upper limit is also advantageous in terms of weight reduction, space saving, and flexibility when using the laminate as, for example, a circuit board, an electronic device, etc.

[0048] In one embodiment, the boundary between the metal-containing polymer layer and the polymer layer is clearly distinguishable, which may be confirmed as a difference in electron density in a cross-sectional image in the thickness direction of a scanning transmission electron microscope (STEM).

[0049] <Polymer> Each of the polymer layer and the metal-containing polymer layer is typically a single layer, but may be composed of multiple layers. Examples of the polymer contained in the polymer layer and the polymer contained in the metal-containing polymer layer include polypropylene (PP), polyester {polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc.}, polyethersulfone (PES), polycarbonate (PC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyacetal (POM), polyarylate (PAR), polyphenylene ether (PPE), modified polyphenylene ether (m-PPE), polyphenylene sulfide (PPS), polyether ketone (PEK), polyether ether ketone (PEEK), polyimide (PI), polyphthalamide (PPA), polyethernitrile (PENt), polybenzimidazole (PBI), polycarbodiimide, polymethacrylamide, nitrile rubber, acrylic rubber, polyethylene tetrafluoride, epoxy resin, phenolic resin, Examples of the resin include melamine resin, urea resin, polymethyl methacrylate resin (PMMA), polybutene, polypentene, ethylene-propylene copolymer, ethylene-butene-diene copolymer, polybutadiene, polyisoprene, ethylene-propylene-diene copolymer, butyl rubber, polymethylpentene (PMP), polystyrene (PS), styrene-butadiene copolymer, polyethylene (PE), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), phenol novolak, benzocyclobutene, polyvinylphenol, polychloroprene, polyoxymethylene, polysulfone (PSF), polyphenylsulfone resin (PPSU), cycloolefin polymer (COP), acrylonitrile-butadiene-styrene resin (ABS), acrylonitrile-styrene resin (AS), polytetrafluoroethylene resin (PTFE), polychlorotrifluoroethylene (PCTFE), and silicone resin (polysiloxane).

[0050] Suitable examples of the polymer include nitrogen-containing polymers and sulfur-containing polymers. Examples of nitrogen-containing polymers include polyimide (PI), polyphthalamide (PPA), polyethernitrile (PENt), polybenzimidazole (PBI), polycarbodiimide, polymethacrylamide, nitrile rubber, urea resin, acrylonitrile-butadiene-styrene resin (ABS), and acrylonitrile-styrene resin (AS). Examples of sulfur-containing polymers include polyphenylene sulfide (PPS), polysulfone (PSF), and polyphenylsulfone resin (PPSU).

[0051] The polymer is preferably a polyimide or a combination of a polyimide and another resin. In this case, the proportion of the other resin may be less than 50% by mass, 30% by mass or less, or 10% by mass or less, relative to 100% by mass of the total polymer. For example, the polymer layer may have a polyimide layer and a layer other than a polyimide layer.

[0052] (Polyimide) A preferred embodiment of the polymer is polyimide. In a preferred embodiment, the metal-containing polymer layer is a metal-containing polyimide layer, and the polymer layer is a polyimide layer. Since polyimide has excellent electrical insulation, when the polymer layer is a polyimide layer, it is useful as an insulating region in a laminate. As the polyimide, from the viewpoint of being likely to have excellent chemical stability, for example, thermoplastic polyimide can be mentioned. Polyimide means a resin having an imide group in its molecular structure, and for example, a polyimide represented by the following general formula (1): (wherein n is a positive integer, X is a tetravalent group, and Y is a divalent group), n is, for example, an integer of 1 to 200.

[0053] Polyimides can be obtained, for example, by synthesizing a polyamic acid (polyimide precursor) from an acid anhydride and a diamine, and then partially or completely imidizing the polyimide precursor. In this case, X is an organic group corresponding to the acid anhydride, and Y is an organic group corresponding to the diamine. In addition to the acid anhydride and the diamine, the polyimide precursor may contain other components (e.g., a solvent, a photopolymerization initiator, a radical polymerizable compound, a silane coupling agent, a rust inhibitor, an organic titanium compound, a plasticizer, a thermal crosslinking agent, and a thermal polymerization initiator). The various raw materials used to obtain the polyimide precursor may be used alone or in combination of two or more.

[0054] The metal-containing polyimide layer and the polyimide layer may be formed using a commercially available polyimide film. Examples of commercially available polyimide films include Kapton H, Kapton V, and Kapton EN (trade names, all manufactured by DuPont-Toray Co., Ltd.), Apical NPI, Pixio FRS (trade names, manufactured by Kaneka Corporation), Upilex S, Upilex SGA, Upilex VT, and Upilex NVT (trade names, manufactured by UBE). A metal-containing polyimide layer may be formed by infiltrating a metal into a partial region of such a polyimide film. From the viewpoint of facilitating the formation of a metal-containing polyimide layer due to the moderate progress of hydrolysis or thermal decomposition during plating or reduction, and thus facilitating excellent adhesion, it is preferable to use Kapton H as the commercially available polyimide film.

[0055] <Ratio (IR1) / (IR2)> In one embodiment, at least a portion of the polymer in the metal-containing polymer layer may have a molecular structure resulting from modification (e.g., thermal decomposition or hydrolysis) of the polymer in the polymer layer. For example, when a metal is deposited on a polymer substrate and then irradiated with laser light or heated, the surface of the polymer substrate may undergo thermal decomposition, which facilitates penetration of the metal into the polymer substrate, thereby forming a metal-containing polymer layer. Furthermore, for example, when a polymer substrate is immersed in a plating solution (especially an alkaline plating solution), the plating solution penetrates the polymer substrate and metal precipitates from the plating solution, thereby forming a metal-containing polymer layer. If only polymer modification occurs, the substrate may be easily destroyed due to a decrease in strength. However, the formation of a metal-containing polymer layer can improve adhesion while maintaining the substrate strength. Suitable examples of polymers that can be thermally decomposed and / or hydrolyzed include polyimide, polyester, polycarbonate, etc., with polyimide being preferred. The interaction between the carbonyl group of polyamic acid, a hydrolyzate of polyimide, and the metal may improve adhesion between the metal layer and the metal-containing polymer layer.

[0056] The modification of the polymer can be confirmed by infrared (IR) absorption spectroscopy. In one embodiment, in infrared absorption spectroscopy of the metal-containing polymer layer and the polymer layer, the ratio (IR1) / (IR2) of the peak intensity of a first peak (IR1) derived from a first structure in the main chain of the polymer to the peak intensity (IR2) of a second peak (IR2) derived from a second structure in the main chain is controlled within a predetermined range. The ratio (IR1) / (IR2) can reflect the degree of modification (e.g., thermal decomposition or hydrolysis) of the polymer.

[0057] As an example, when the polymer is polyimide and the modified product is a hydrolyzed product (polyamic acid), the ratio (IR1) / (IR2) may be calculated as follows, focusing on the C=O structure (first structure) of the imide ring in the main chain of the polyimide and the C=C structure (second structure) of the benzene ring in the main chain of the polyimide. When the imide ring of the polyimide is hydrolyzed, it opens to produce polyamic acid. In the infrared spectrum, a peak (first peak) due to C=O stretching appears at 1702 cm -1 ~1722cm-1 A peak (second peak) due to C═C stretching was observed in the range of 1494 cm -1 ~1514cm -1 Based on the peak intensities of these peaks, the ratio (IR1) / (IR2) (also referred to as the imide degree in this disclosure) of the polyimide can be calculated. A smaller imide degree indicates a higher degree of hydrolysis.

[0058] As another example, when the polymer is a polyester and the modified product is a hydrolyzate, the peak (first peak) derived from the C-O stretching of the C-O structure (first structure) of the ester moiety in the main chain of the polyester is 1240 cm -1 ~1260cm -1 The peak (second peak) due to the C═C stretching of the C═C structure (second structure) of the benzene ring in the main chain is observed in the range of 1495 cm -1 ~1515cm -1 The smaller the ratio of the first peak to the second peak (IR1) / (IR2), the greater the degree of hydrolysis.

[0059] As another example, when the polymer is polycarbonate and the modified product is a hydrolyzate, the peak (first peak) derived from the C-O stretching of the C-O structure (first structure) of the carbonate ester moiety in the main chain of the polycarbonate is 1760 cm -1 ~1780cm -1 The peak (second peak) due to the C═C stretching of the C═C structure (second structure) of the benzene ring in the main chain is observed in the range of 1495 cm -1 ~1515cm -1 The smaller the ratio of the first peak to the second peak (IR1) / (IR2), the greater the degree of hydrolysis.

[0060] The minimum value of the ratio (IR1) / (IR2) between the metal-containing polymer layer and the polymer layer can be an indicator of the degree of modification of the portion where the modification of the polymer is significant. The minimum value is preferably 0.2 or more, or 0.3 or more, from the viewpoint of easily maintaining the strength of the metal-containing polymer layer, and is preferably 1.5 or less, or 1.1 or less, or 1.0 or less, or 0.9 or less, from the viewpoint of good adhesion. The minimum value of the ratio (IR1) / (IR2) can essentially be indicated by the portion of the metal-containing polymer layer closest to the metal layer, but such a portion is excluded from the measurement area due to the difficulty of microscopic IR measurement. Therefore, the minimum value may be a value indicated by a certain region within the polymer layer. Even in this case, the magnitude of the minimum value is useful as an indicator reflecting the degree of modification of the polymer in the metal-containing polymer layer.

[0061] The maximum value of the ratio (IR1) / (IR2) between the metal-containing polymer layer and the polymer layer can be an indicator of the degree of modification of a portion where the polymer is not modified or is only slightly modified. In one embodiment, when the minimum value of the ratio (IR1) / (IR2) is 0.2 or more and 1.5 or less, the maximum value may be greater than the minimum value and may be 0.5 or more and 2.0 or less.

[0062] <Zerovalent and / or Monovalent Metal, Metal Chemically Bonded to Nitrogen Atom> The metal-containing polymer layer preferably contains a zero-valent and / or monovalent metal (in one embodiment, as the "same type" metal of the present disclosure), and more preferably contains a zero-valent and monovalent metal. A monovalent metal makes it easy to realize an embodiment in which the metal is chemically bonded to the nitrogen atom. Furthermore, it is preferable that the metal-containing polymer layer does not contain a divalent metal. The presence of a divalent metal may reduce the mechanical strength of the metal-containing polymer layer, so a metal-containing polymer layer that does not contain a divalent metal is advantageous in that it can suppress such a decrease in mechanical strength.

[0063] In a preferred embodiment, the laminate (in one embodiment, the metal-containing polymer layer) contains a nitrogen atom (N) and a metal chemically bonded to the nitrogen atom. In one embodiment, the metal chemically bonded to the nitrogen atom is the "same type" metal of the present disclosure. The nitrogen atom may be derived from a nitrogen-containing polymer, for example, from a polyimide (particularly, an imide bond in a polyimide). In one embodiment, the polymer constituting the metal-containing polymer layer and the polymer constituting the polymer layer are nitrogen-containing polymers, and the metal-containing polymer layer contains a metal chemically bonded to a nitrogen atom. Preferred examples of metals that can chemically bond to nitrogen atoms include copper (Cu), silver (Ag), nickel (Ni), chromium (Cr), tin (Sn), zinc (Zn), and alloys containing these, with copper being more preferred. The metal chemically bonded to the nitrogen atom contributes to improving adhesion between the metal layer and the metal-containing polymer layer due to the anchor effect. The presence or absence of a metal chemically bonded to a nitrogen atom may be confirmed by detecting a peak derived from the chemical bond between nitrogen and the metal using X-ray photoelectron spectroscopy (XPS). A more detailed confirmation method will be described in Examples. In one aspect, the chemical bond between the nitrogen atom and the metal can be formed when a metal is deposited on a polymer substrate and then irradiated with laser light or heated, when the polymer substrate is immersed in a plating solution (particularly an alkaline plating solution), or the like.

[0064] For example, when a metal-containing polymer layer contains copper as the metal (in one embodiment, as the "same type" metal of the present disclosure) and a nitrogen-containing polymer as the polymer, a peak (also referred to as a first peak) may be present in the range of 571 eV to 574 eV in X-ray photoelectron spectroscopy measurement of the metal-containing polymer layer. The first peak indicates the presence of a chemical bond between nitrogen and monovalent copper. Such a chemical bond is advantageous for achieving good adhesion between the metal layer and the metal-containing polymer layer due to the anchoring effect of the metal in the metal-containing polymer layer. In addition to the first peak, a second peak preferably exists in the range of 563 eV to 566 eV. The second peak indicates the presence of zero-valent copper (i.e., copper present as a single metal). The zero-valent metal functions as a filler in the metal-containing polymer layer. Therefore, the presence of a zero-valent metal can contribute to the prevention of fracture of the metal-containing polymer layer by improving the mechanical strength of the metal-containing polymer layer. Furthermore, it is more preferable that a third peak does not exist in the range of 934 eV to 937 eV. The third peak indicates the presence of divalent copper, which, when present as cupric oxide, can reduce the mechanical strength of the metal-containing polymer layer.

[0065] <Metal Amount in Metal-Containing Polymer Layer> The amount of metal contained in the metal-containing polymer layer is preferably 1 atomic % or more, or 1.2 atomic % or more, from the viewpoint of obtaining good adhesion due to the anchor effect and filler effect of the metal. On the other hand, since excessive diffusion of the metal into the polymer can be suitably suppressed, and the strength of the metal-containing polymer layer can be easily maintained high, the metal amount in the metal-containing polymer layer is preferably 20 atomic % or less, or 15 atomic % or less, or 14 atomic % or less, or 12 atomic % or less, or 10 atomic % or less, or 8 atomic % or less, or 5 atomic % or less. When all of the metals in the metal-containing polymer layer are the "same type" metals as defined in the present disclosure, the metal amount in the metal-containing polymer layer is the amount of the "same type" metal. The metal amount in the metal-containing polymer layer can be determined by identifying the metal species present in the metal-containing polymer layer and measuring the total metal amount of the identified metal species using energy dispersive X-ray analysis (EDX analysis) using STEM. In one embodiment, the amount of the metal species present in the largest amount by atomic number among the metal species contained in the metal-containing polymer layer may be within the above range. The metal amount in the metal-containing polymer layer tends to be greater when the manufacturing conditions of the laminate are more severe (for example, when the laminate is manufactured under higher energy laser light irradiation, higher temperature heating, or immersion in a more alkaline plating solution).

[0066] Furthermore, the metal concentration at a position 20 nm toward the metal layer from the boundary between the metal-containing polymer layer and the polymer layer is preferably 1.0 atomic % or more, 1.3 atomic % or more, 1.4 atomic % or more, 1.8 atomic % or more, or 2.0 atomic % or more, in order to obtain the anchoring effect and filler effect of the metal throughout the metal-containing polymer layer. On the other hand, in order to easily maintain the strength of the metal-containing polymer layer at a high level, the metal concentration is preferably 5.0 atomic % or less, 4.5 atomic % or less, or 4.0 atomic % or less. The metal concentration at a position 20 nm toward the metal layer from the boundary between the metal-containing polymer layer and the polymer layer can be determined by EDX analysis using STEM.

[0067] <Sodium Content in Metal-Containing Polymer Layer> The metal-containing polymer layer preferably contains sodium in addition to the metal. In a typical embodiment, the sodium is derived from the plating solution. To control the sodium content in the metal-containing polymer layer, when the metal layer (e.g., the first metal layer) is formed by plating, the chemical composition (particularly the sodium concentration) of the plating solution, the plating time, and / or the plating temperature may be appropriately adjusted.

[0068] The amount of sodium contained in the metal-containing polymer layer is preferably 0.1 atomic % or more, more preferably 1 atomic % or more. This makes it easy to achieve excellent adhesion between the metal layer, the metal-containing polymer layer, and the polymer layer due to the anchoring effect of sodium. It is presumed that the anchoring effect is caused by the interaction between the metal in the metal-containing polymer layer and sodium. The amount of sodium contained in the metal-containing polymer layer is preferably 10 atomic % or less, more preferably 8 atomic % or less, and even more preferably 6 atomic % or less. This makes it possible to suitably suppress excessive diffusion of sodium into the polymer, making it easy to maintain high strength of the metal-containing polymer layer.

[0069] <<Laminate Manufacturing Method>> One aspect of the present invention provides a method for manufacturing the laminate of the present disclosure. In one aspect, the laminate manufacturing method includes a step (coating step) of applying a metal (which may be an element, an alloy, or a compound) onto a polymer substrate. When a metal oxide is applied, the method may further include a step (reduction step) of reducing the metal oxide. In one aspect, the reduction may be performed by laser light irradiation and / or heating, and in one aspect, by laser light irradiation. The laminate manufacturing method including the coating step may further include a plating step, for example, an electroless metal plating step. In one aspect, the plating step, for example, the electroless metal plating step, may be performed after the reduction step. In one aspect, the metal layer in the laminate manufacturing method may be formed by a coating step of applying a metal oxide onto the polymer substrate and a reduction step of reducing the metal oxide.

[0070] In the method for producing a laminate, the metal layer may be formed by: a coating step of applying a dispersion containing particles of a metal (which may be an elemental metal, an alloy, or a compound) onto a polymer substrate to form a coating film; and a baking step of baking the coating film, optionally after drying, by laser light irradiation and / or heating. In one embodiment, the layer formed by these steps may be the metal layer of the present disclosure (and therefore a single metal layer). Alternatively, in one embodiment, a second metal layer may be formed by these steps.

[0071] In one embodiment, a first metal layer may be formed on the second metal layer by immersing a composite formed by forming the second metal layer on the polymer substrate in a plating solution, for example, an electroless metal plating solution.

[0072] One aspect of the present invention provides a method for producing a laminate, comprising the steps of: forming a first metal layer having a thickness of 0.1 μm or more and 1000 μm or less; forming a second metal layer having a thickness of 0.01 μm or more and 10 μm or less; forming a metal-containing polymer layer having a thickness of 0.04 μm or more and 10 μm or less; and forming a polymer layer having a thickness of 1.0 μm or more and 1000 μm or less, wherein the first metal layer, the second metal layer, the metal-containing polymer layer, and the polymer layer are arranged in this order, and the first metal layer, the second metal layer, and the metal-containing polymer layer contain the same type of metal.

[0073] The step of forming the second metal layer preferably includes the steps of: a coating step of applying a dispersion containing metal particles and / or metal oxide particles onto a substrate to form a dispersion layer; a drying step of drying the dispersion layer to form a dry coating film on the substrate; and a step of heating the dry coating film to form the second metal layer.

[0074] Furthermore, the process of forming the second metal layer preferably includes the following steps: a coating process of applying a dispersion containing metal particles and / or metal oxide particles onto a substrate to form a dispersion layer; a drying process of drying the dispersion layer to form a dry coating film on the substrate; and a process of irradiating a laser to bake the dried coating film to form the second metal layer.

[0075] The step of forming the first metal layer preferably includes a step of forming the first metal layer by immersing the second metal layer in a plating solution, and the plating solution preferably has a pH of 10 or more and 14 or less.

[0076] In the method for producing a laminate, the metal particles and / or metal oxide particles are preferably copper particles and / or copper oxide particles.

[0077] Specific examples of methods for producing a laminate when a first metal layer and a second metal layer are formed include the following first to third methods. First method: A method comprising the steps of: preparing a polymer substrate; applying a dispersion containing metal oxide particles to the polymer substrate to form a coating film (a coating step); optionally, reducing the coating film to obtain a second metal layer (a reduction step); and plating the second metal layer to form a first metal layer on the second metal layer, while converting a portion of the polymer substrate facing the second metal layer into a metal-containing polymer layer and the remainder into a polymer layer (a plating step). Second method: A method comprising the steps of: preparing a polymer substrate; applying a dispersion containing elemental metal particles to the polymer substrate to form a second metal layer (a coating step); and plating the second metal layer to form a first metal layer on the second metal layer, while converting a portion of the polymer substrate facing the second metal layer into a metal-containing polymer layer and the remainder into a polymer layer (a plating step). The third method includes the steps of: forming a second metal layer; forming a polymer layer on the second metal layer by a casting method, and then allowing the polymer layer to stand after casting to form a metal-containing polymer layer between the second metal layer and the polymer layer; and forming a first metal layer on the second metal layer by applying a dispersion containing metal particles to the second metal layer, plating the second metal layer, or sputtering a metal onto the second metal layer (the coating step, plating step, or sputtering step). In the third method, the second metal layer may be, for example, a commercially available metal foil. Each method may include any steps other than those described above.

[0078] <Dispersion> The dispersion may contain metal particles (which may be a simple substance, an alloy, or a compound). The dispersion may further contain a dispersion medium, a dispersant, and / or a reducing agent. The dispersion may be prepared by adding a dispersion medium and, optionally, a dispersant to the particles, and stirring and dispersing them using a known method such as a homogenizer. Examples of each component of the dispersion will be described below.

[0079] <Particles> The metal contained in the particles contained in the dispersion may be one or more metals selected from the group consisting of copper (Cu), silver (Ag), nickel (Ni), chromium (Cr), tin (Sn), zinc (Zn), and alloys containing these metals, and may exist as a metal compound, such as a metal oxide. The particles may have a core / shell structure. For example, the core and / or shell may be metal, and the core and shell may contain different metals. The metal may also form a complex. The dispersion preferably contains copper or copper oxide. Examples of copper oxide include cuprous oxide (CuO) and cupric oxide (CuO). However, cuprous oxide is preferred because it has a high affinity with polymer substrates (especially polyimide substrates) and easily achieves good adhesion between the metal layer and the metal-containing polymer layer. Cuprous oxide may be obtained, for example, by hydrazine reduction of a copper salt.

[0080] The average particle diameter of the particles is preferably 1 nm or more, or 3 nm or more, or 5 nm or more, and preferably 100 nm or less, or 50 nm or less, or 40 nm or less. Here, the average particle diameter refers to the particle diameter when dispersed in a dispersion, and is a value measured by the cumulant method (e.g., using an FPAR-1000 manufactured by Otsuka Electronics Co., Ltd.). That is, the average particle diameter is not limited to the primary particle diameter, and may also be the secondary particle diameter. An average particle diameter of 100 nm or less is preferable in that it enables metal layer formation at low temperatures, broadens the versatility of substrates, and tends to facilitate the formation of fine patterns on substrates. Furthermore, an average particle diameter of 1 nm or more is preferable in that the dispersion has good dispersion stability, the long-term storage stability of the dispersion is good, and a uniform thin film can be produced. In one embodiment, the particles in the dispersion are substantially metal particles only. In this case, the value of the average particle diameter measured for the dispersion can be considered the average particle diameter of the metal particles.

[0081] The proportion of particles in 100% by mass of the dispersion is preferably 5% by mass or more, or 10% by mass or more, or 15% by mass or more, and preferably 60% by mass or less, or 55% by mass or less, or 50% by mass or less.

[0082] <Dispersion Medium> Examples of dispersion media that can be used include alcohols (monohydric alcohols and polyhydric alcohols (e.g., glycols)), ethers of alcohols (e.g., glycols), and esters of alcohols (e.g., glycols). These may be used alone or in combination, and are selected in consideration of the coating method, volatility, coating equipment, and solvent resistance of the substrate (i.e., the substrate to be coated), etc. The dispersion preferably contains one or more dispersion media selected from the group consisting of 1-hexanol, 1-heptanol, and 1-octanol, and more preferably one or more dispersion media selected from the group consisting of 1-heptanol and 1-octanol, in terms of slow drying and less aggregation of the dispersion when continuous printing is used, and good intermittent stability and less abnormal flight when inkjet printing is used.

[0083] The boiling point of the dispersion medium is preferably high from the viewpoint of improving printing continuity, and is, for example, preferably 50° C. or higher, more preferably 100° C. or higher, and even more preferably 150° C. or higher. On the other hand, from the viewpoint of obtaining good functionality as a dispersion medium, the boiling point is preferably 400° C. or lower, more preferably 300° C. or lower, and even more preferably 250° C. or lower.

[0084] The content of the dispersion medium in the entire dispersion is preferably 30% by mass or more, or 40% by mass or more, or 50% by mass or more, and preferably 95% by mass or less, or 90% by mass or less.

[0085] <Dispersant> A compound capable of dispersing particles in a dispersion medium can be used as the dispersant. The number-average molecular weight of the dispersant is preferably 300 or more, or 350 or more, or 400 or more, and preferably 300,000 or less, or 200,000 or less, or 150,000 or less. The number-average molecular weight in the present disclosure is a value determined using gel permeation chromatography in terms of standard polystyrene. A number-average molecular weight of 300 or more tends to provide excellent insulating properties and contribute significantly to the dispersion stability of the dispersion, while a number-average molecular weight of 300,000 or less is preferred in terms of handleability. The dispersant preferably has a group that has affinity for the metal in the particles, particularly a metal oxide. Examples of such groups include a phosphate group, a hydroxyl group, an amino group, and a carboxy group. From the viewpoint of affinity with the particles and suppression of particle aggregation due to steric hindrance, the dispersant preferably contains or is a phosphorus-containing organic compound, or contains or is a phosphate ester, or contains or is a polymeric phosphate ester. The polymer chain may be a hydrocarbon chain. When a second metal layer is formed using the dispersion and a first metal layer is formed by a method such as plating, the adhesion between the first metal layer and the second metal layer tends to be better when the dispersion contains a phosphorus-containing organic compound.

[0086] Known dispersants may be used. Examples include polymers having basic groups, such as salts of long-chain polyaminoamides and polar acid esters, unsaturated polycarboxylic acid polyaminoamides, polycarboxylic acid salts of polyaminoamides, and salts of long-chain polyaminoamides and acid polymers. Other examples include alkylammonium salts, amine salts, and amidoamine salts of polymers such as acrylic (co)polymers, modified polyester acids, polyether ester acids, polyether carboxylic acids, and polycarboxylic acids. Commercially available dispersants may also be used.

[0087] The acid value (mg KOH / g) of the dispersant is preferably 20 or more, or 30 or more, and preferably 130 or less, or 100 or less. When the acid value is in the above range, the dispersion stability of the dispersion is good, which is preferable. In particular, when the average particle size of the copper oxide-containing particles and / or copper-containing particles is small, an acid value in the above range is effective. Specifically, preferred examples include "DISPERBYK-102" (acid value 101), "DISPERBYK-140" (acid value 73), "DISPERBYK-142" (acid value 46), "DISPERBYK-145" (acid value 76), "DISPERBYK-118" (acid value 36), and "DISPERBYK-180" (acid value 94), all manufactured by BYK-Chemie.

[0088] Furthermore, the difference between the amine value (mg KOH / g) and the acid value of the dispersant ([amine value] - [acid value]) is preferably -50 or more and 0 or less. The amine value indicates the total amount of free bases and free base-derived moieties, and the acid value indicates the total amount of free fatty acids and free fatty acid-derived moieties. The amine value and acid value are measured by methods conforming to JIS K 7700 or ASTM D2074, respectively. When the value of [amine value] - [acid value] is -50 or more and 0 or less, the dispersion stability of the dispersion is good, which is preferable. The value of [amine value] - [acid value] is more preferably -40 or more and 0 or less, and even more preferably -20 or more and 0 or less.

[0089] The mass ratio of the dispersant to the total mass of the metal in the dispersion (dispersant mass / total mass of metal) is preferably 0.0050 or more, or 0.050 or more, or 0.10 or more, and preferably 0.30 or less, or 0.25 or less, or 0.23 or less. The "total mass of metal" refers to the total mass of the metal in the form present in the dispersion (e.g., elemental metal, alloy, or metal compound). The amount of dispersant affects the dispersion stability of the dispersion; a small amount tends to cause particles to aggregate, while a large amount tends to improve the dispersion stability of the dispersion. However, if the dispersant content in the dispersion is 35% by mass or less, the influence of dispersant-derived residues in the metal layer can be suppressed and conductivity can be improved. In one aspect, the amount of dispersant in 100% by mass of the dispersion is preferably 0.5% by mass or more, or 0.8% by mass or more, or 1.0% by mass or more, and preferably 35% by mass or less, or 30% by mass or less, or 25% by mass or less.

[0090] <Reducing Agent> When the dispersion contains metal oxide particles, the dispersion may contain a reducing agent. Examples of reducing agents include hydrazine, sodium, sodium borohydride, potassium iodide, sulfite, sodium thiosulfate, formic acid, oxalic acid, ascorbic acid, iron(II) sulfide, tin(II) chloride, diisobutylaluminum hydride, and carbon, with hydrazine being preferred. The hydrazine may be in the form of hydrazine hydrate (i.e., the term "hydrazine" in the present disclosure encompasses hydrazine hydrate). A dispersion containing a reducing agent can more effectively reduce metal oxides and form a metal layer with lower resistance. Hydrazine is also advantageous in maintaining the dispersion stability of the dispersion. The hydrazine in the dispersion may be present as a component in the particles and / or separately from the particles.

[0091] The content of the reducing agent in the dispersion (excluding water of hydration in the case of a hydrate) is preferably adjusted in proportion to the amount of metal oxide, taking into account the required reducing properties. In one embodiment, the mass ratio of the reducing agent to the metal oxide in the dispersion (reducing agent mass / metal oxide mass) is preferably 0.0001 or more, and preferably 0.1 or less, or 0.05 or less, or 0.03 or less. When the mass ratio of the reducing agent is 0.0001 or more, the dispersion has good dispersion stability and the metal layer has low resistance, which is preferable. When the mass ratio is 0.1 or less, the dispersion has good long-term stability.

[0092] Two or more reducing agents may be used in combination. For example, when hydrazine and a reducing agent other than hydrazine are used in combination, the total content of hydrazine and the reducing agent other than hydrazine in the dispersion is preferably adjusted in proportion to the amount of metal oxide, taking into account the required reducing properties. In one embodiment, the total mass ratio of hydrazine and the reducing agent other than hydrazine to the metal oxide in the dispersion (total mass of reducing agents / mass of metal oxide) is preferably 0.0001 or more, and preferably 0.1 or less, or 0.05 or less, or 0.03 or less. When the total mass ratio of the reducing agents is 0.0001 or more, the dispersion has good dispersion stability and the metal layer has low resistance, which is preferable. When the total mass ratio is 0.1 or less, the dispersion has good long-term stability.

[0093] The dispersion can be produced by mixing the ingredients and dispersing them using a mixer, ultrasonic wave method, three-roll method, two-roll method, attritor, homogenizer, Banbury mixer, paint shaker, kneader, ball mill, sand mill, planetary mixer, or the like. The viscosity of the dispersion can be designed depending on the intended application method. For example, the viscosity of a dispersion for screen printing is preferably 50 mPa·s or more, more preferably 100 mPa·s or more, and even more preferably 200 mPa·s or more, and preferably 50,000 mPa·s or less, more preferably 10,000 mPa·s or less, and even more preferably 5,000 mPa·s or less. The viscosity of the dispersion is measured at 23°C using a cone-plate rotational viscometer.

[0094] Metal oxides tend to be more stable than elemental metals, and the use of a dispersion containing metal oxide particles can be advantageous in terms of storage stability of the dispersion. From this perspective, the first method described above is preferred. The first method will be described in more detail below.

[0095] <Examples of steps in the method for producing a laminate> <Preparation of polymer substrate> The polymer substrate may be prepared by using a commercially available polymer film, forming a polymer substrate, or the like, as described above.

[0096] <Coating Step> In the coating step, a dispersion containing metal oxide particles is applied to form a coating film containing a metal oxide (metal oxide-containing film). Examples of methods for applying the dispersion include inkjet printing, screen printing, intaglio direct printing, intaglio offset printing, flexographic printing, and offset printing. Coating is performed using methods such as die coating, spin coating, slit coating, bar coating, knife coating, spray coating, and dip coating.

[0097] From the viewpoint of facilitating the formation of a highly uniform wiring pattern, the thickness of the coating film is preferably 1 nm or more, 10 nm or more, or 100 nm or more, and preferably 10,000 nm or less, 8,000 nm or less, or 7,000 nm or less. However, the thickness of the coating film may be controlled to such an extent that each layer (metal layer and / or metal-containing polymer layer) in this embodiment has a predetermined thickness. The thickness of the coating film can be controlled by the amount of metal oxide-containing dispersion applied, the number of applications, etc.

[0098] <Drying Step> The method for producing a laminate may include a drying step. In the drying step, the coating film is dried. For example, in the drying step, the coating film obtained in the above <Coating Step> is dried. Drying conditions are, for example, 60 to 120°C and 5 minutes to 5 hours. In the drying step, the coating film may be dried under reduced pressure below atmospheric pressure.

[0099] From the viewpoint of facilitating the formation of a highly uniform wiring pattern, the thickness of the coating film after drying is preferably 1 nm or more, 10 nm or more, or 100 nm or more, and preferably 10,000 nm or less, 8,000 nm or less, or 7,000 nm or less. However, the thickness of the coating film after drying may be controlled to such an extent that each layer (metal layer and / or metal-containing polymer layer) having a predetermined thickness in this embodiment is produced. The thickness of the coating film after drying can be controlled by the thickness of the coating film before drying, the drying temperature, the drying time, etc.

[0100] <Reduction Step> The method for producing a laminate may include a reduction step of reducing the coating film. For example, in the reduction step, the oxide-containing film obtained in the coating step is reduced. The reduction step may be performed simultaneously with the drying step and / or the plating step, or may be performed separately from these steps. In the reduction step, a metal-containing film is obtained by reducing the coating film (e.g., oxide-containing film). In the reduction step, oxide-containing particles in the oxide-containing film are reduced, thereby generating metal, and the metal itself is fused and integrated to form a metal layer. However, if the oxide-containing film is used as the metal layer as is, this step can be omitted.

[0101] Examples of reduction methods include reduction in a nitrogen atmosphere at a temperature of 100°C to 500°C, reduction in a hydrogen-mixed nitrogen atmosphere (e.g., a gas mixture containing approximately 3% by volume of hydrogen in a total of 100% by volume of hydrogen and nitrogen), reduction by laser light irradiation, and immersion of an oxide-containing film in a reduction solution. From the viewpoint of easily ensuring the thickness of the metal-containing polymer layer and easily improving adhesion, reduction by laser light irradiation is preferred. By appropriately setting the irradiation intensity of the laser light, it is easy to modify a portion of the polymer while maintaining the mechanical strength of the metal layer and polymer layer. The desired metal-containing polymer layer can be formed by diffusing the metal into the modified portion of the polymer. In particular, a method in which a plating process is performed after laser light irradiation easily promotes diffusion of the metal into the modified polymer. Furthermore, by adjusting the laser light irradiation conditions, patterning of thin lines on the order of several tens of nanometers can be performed simultaneously with reduction. This makes it possible to easily form fine metal wiring as the metal layer.

[0102] (Reduction by Laser Beam) As a reduction method using laser beam, a known laser beam irradiation device having a laser beam irradiation unit may be used. Laser beams are preferred from the viewpoint of easily exposing the substrate to high-intensity light in a short time, thereby easily raising the temperature of the dried coating film formed on the substrate to a high temperature in a short time, and consequently facilitating baking (e.g., facilitating reduction of cuprous oxide). The laser beam method is advantageous in that it reduces the baking time, thereby causing less damage to the substrate and is therefore suitable for application to polymer substrates with low heat resistance. Furthermore, the laser beam method has a large degree of freedom in wavelength selection, and therefore is advantageous in that it is easy to select a wavelength taking into account the light absorption wavelength of the dried coating film and / or the light absorption wavelength of the substrate. Furthermore, the laser beam method enables exposure by beam scanning, making it easy to adjust the exposure range. For example, selective light irradiation (drawing) of only the desired area of ​​the dried coating film is possible without using a mask.

[0103] The types of laser light source include YAG (yttrium aluminum garnet), YVO (yttrium vanadate), Yb (ytterbium), semiconductor lasers (GaAs, GaAlAs, GaInAs), carbon dioxide gas, etc. As for the laser, not only the fundamental wave but also higher harmonics may be extracted and used as necessary.

[0104] The central wavelength of the laser beam is preferably 350 nm or more and 600 nm or less. In particular, when cuprous oxide is used as the copper oxide, the cuprous oxide absorbs laser beams having a central wavelength in the above range well, and is therefore uniformly reduced, thereby forming low-resistance metal wiring. When cuprous oxide is used, the central wavelength is more preferably 350 nm or more and 400 nm or less.

[0105] The dried coating film is preferably irradiated with the laser light through a galvanometer scanner. By scanning the dried coating film with the laser light using the galvanometer scanner, metal wiring of any desired shape can be obtained.

[0106] The laser beam irradiation output is preferably 1 mW or more, 10 mW or more, or 20 mW or more from the viewpoint of efficiently performing the desired firing (e.g., reduction of cuprous oxide). From the viewpoint of easily suppressing destruction of the metal wiring due to ablation caused by excessive laser beam output and thus easily obtaining low-resistance metal wiring, the output is preferably less than 200 mW, 100 mW or less, or 50 mW or less. Typically, laser firing at a high output of 200 mW or more promotes sintering of metal particles and further burns off organic matter derived from dispersants and reducing agents in the coating film, thereby reducing the resistance value. Furthermore, laser firing at a high output of 200 mW or more promotes the reduction of metal oxides (e.g., cuprous oxide), making it easier for plating to grow on the reduced metal. On the other hand, in this embodiment, the laser output is set to less than 200 mW, and some of the metal oxides and organic matter are intentionally left behind, thereby forming physical bonds between the metal oxides and organic matter and the substrate, thereby improving adhesion between the substrate and the metal layer. In this case, since the remaining metal oxides and organic substances make it difficult for the plating to grow, the plating growth can be promoted by shaking the sample during plating, as described below. Furthermore, by performing the electroless plating step after laser baking with a reduced output, it is easier to control the thickness of the metal-containing polymer layer and the amount of metal contained in the metal-containing polymer layer within a more preferred range.

[0107] In particular, when cuprous oxide is used as the copper oxide, it is preferable to set the center wavelength of the laser beam to 350 nm or more and 400 nm or less, and to set the irradiation power within the above range. With this center wavelength, the laser beam is almost entirely absorbed by the cuprous oxide, thereby preventing excessive modification of the polymer due to absorption of the laser beam by the polymer substrate. Furthermore, with the above irradiation power, the generation of excessive heat can be prevented by lowering the irradiation power to a level at which the metal oxide is reduced. In this way, it is possible to achieve both the formation of a metal-containing polymer layer by laser beam irradiation and the prevention of a decrease in the strength of the polymer substrate due to modification of the polymer.

[0108] <Degreasing Step> One embodiment of the method of the present disclosure may include a step of degreasing the coating film before the plating step. In one embodiment, direct degreasing without reducing the metal oxide facilitates improved productivity. In another embodiment, degreasing may be performed after reducing the metal oxide (for example, in the reduction step described above). Examples of degreasing methods include UV methods and wet degreasing methods. The degreasing step facilitates an increased growth rate of the subsequent plating, which in turn facilitates improved productivity. This step may also contribute to the porosity of the metal layer (in one embodiment, the first metal layer and the second metal layer) after plating. Note that degreasing may be performed together with electroless plating, in which case the degreasing step may be omitted.

[0109] From the viewpoint of easily achieving excellent interlayer adhesion in the laminate, the degreasing step is preferably carried out by immersing the coating film in a degreasing solution containing a compound having an amino group. Examples of compounds containing an amino group include amino acids such as alanine, arginine, asparagine, cysteine, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine; alkylamines such as methylamine, dimethylamine, ethylamine, trimethylamine, diethylamine, triethylamine, propylamine, isopropylamine, and diisopropylamine; alkanolamines such as 2-aminoethanol, diethanolamine, triethanolamine, N-methylethanolamine, and N,N-dimethylethanolamine; polyamines such as ethylenediamine, diethylenetriamine, tetraethylenepentamine, tris(hydroxymethyl)aminomethane, m-xylylenediamine, p-xylylenediamine, and 1,3-bis(aminomethyl)cyclohexane; aminosulfonic acids such as taurine; aminothiols such as 2-aminoethanethiol; and nitrogen-containing heterocyclic compounds such as 3-picolylamine and 3-pyridinemethanol. From the viewpoint of contributing to the plating growth rate, 2-aminoethanol is particularly preferred.

[0110] The degreasing liquid may be a commercially available product, and specific examples thereof include ALC-009 (containing 2-aminoethanol as a compound having an amino group) available from Uemura Kogyosho Co., Ltd. and Cleaner Securigant 902 (containing 2-aminoethanol as a compound having an amino group) available from Atotech Japan.

[0111] The concentration of the amino group-containing compound in the degreasing solution is preferably 5 mmol / L or more, more preferably 10 mmol / L or more, and even more preferably 20 mmol / L or more from the viewpoint of removing substances that inhibit the plating reaction, and is preferably 100 mmol / L or less, more preferably 90 mmol / L or less, and even more preferably 80 mmol / L or less from the viewpoint of promoting the plating reaction.

[0112] The immersion time of the coating film in the degreasing solution is preferably 1 minute or more, more preferably 2 minutes or more, from the viewpoint of contributing to the plating growth rate. Also, from the viewpoint of reducing damage to the substrate, it is preferably 15 minutes or less, more preferably 10 minutes or less. Immersion under stirring is preferred from the viewpoint of uniform degreasing.

[0113] The immersion temperature is preferably 15° C. or higher, more preferably 30° C. or higher, and even more preferably 40° C. or higher in order to enhance the effect of accelerating the plating growth rate. In addition, from the viewpoint of reducing damage to the substrate, the immersion temperature is preferably 70° C. or lower, and more preferably 60° C. or lower.

[0114] <Plating Step> In the plating step, electroless plating, electroplating, or both may be performed. For example, the second metal layer obtained in the reduction step may be treated as a seed layer, and then electroless plating and / or electroplating may be performed to obtain a first metal layer. After the plating step, the metal layer may be dried at 100°C for about 1 hour to remove moisture contained in the metal layer.

[0115] By appropriately setting the conditions for the plating step and the reduction step, it is easy to form a desired metal-containing polymer layer. For example, when the second metal layer is formed by reduction using laser light irradiation in the reduction step, by appropriately setting the irradiation intensity of the laser light, it is easy to modify a portion of the polymer while ensuring the mechanical strength of the second metal layer and the polymer layer. In particular, by performing the plating step after laser light irradiation, the metal contained in the first metal layer and / or the second metal layer is easily diffused into the modified portion of the polymer substrate, and as a result, it is easy to form a desired metal-containing polymer layer.

[0116] In one embodiment, plating may be performed on the coating film after the drying step, which may or may not have undergone a reduction step and / or a degreasing step. In one embodiment, the plating is electroless plating. In one embodiment, productivity is easily improved by directly plating without reducing the oxide-containing film. Electroless plating may reduce part or all of the metal oxide in the oxide-containing film, or the oxide may not be reduced. In another embodiment, electroless plating of a metal-containing film obtained by reducing the oxide-containing film (e.g., wet reduction) easily improves conductivity. Electroless plating can form a metal layer composed of a metal oxide and / or metal layer and a plating layer. Because electroless plating can easily form a thick metal layer, it is particularly advantageous when producing a laminate for applications requiring a large current. Electroless plating is also advantageous in terms of its wide applicability to patterns. A general electroless plating method may be used as the plating method. For example, electroless plating may be performed together with the reduction step, degreasing step, or cleaning step.

[0117] A plating solution is used for electroless plating. The coating film after the drying process is prone to peeling due to external stress, which can lead to inconsistent plating deposition. In this case, stress tends to concentrate in one area, resulting in peeling of the coating film during the plating process. In one embodiment, the plating solution contains EDTA (ethylenediaminetetraacetic acid). EDTA functions as a complexing agent and forms a highly stable complex with metal ions (e.g., copper ions). This is thought to contribute to preventing peeling of the coating film by suppressing side reactions in the plating bath, stabilizing the bath, and promoting uniform plating deposition. Furthermore, EDTA is stable even in high-temperature solutions, and therefore contributes to accelerating plating speed when a plating solution containing EDTA is used at elevated temperatures (e.g., 30°C or higher). Furthermore, plating with a plating solution containing EDTA (ethylenediaminetetraacetic acid) after wet reduction promotes metal plating growth, which tends to improve productivity. The amount of EDTA in the plating solution is preferably 7 g / L or more, or 10 g / L or more, or 15 g / L or more from the viewpoint of obtaining the advantages of EDTA well, and is preferably 50 g / L or less, or 45 g / L or less, or 40 g / L or less from the viewpoint of reducing impurities in the plating deposit and facilitating low electrical resistance. In one embodiment, the plating solution also contains Rochelle salt. Rochelle salt functions as a complexing agent. Plating solutions containing Rochelle salt generally react at low temperatures and have a lower pH than plating solutions containing EDTA, which makes it less likely to embrittle the substrate, prevents cohesive failure of the substrate, and facilitates improved adhesion. On the other hand, while plating reactivity is generally low, the plating reactivity can be improved by shaking the sample, as described below. The amount of Rochelle salt in the plating solution is preferably 30 g / L or more, or 40 g / L or more, from the viewpoint of obtaining the advantages of Rochelle salt well, and is preferably 100 g / L or less, or 85 g / L or less, from the viewpoint of reducing impurities in the plating deposit and facilitating low electrical resistance. Furthermore, particularly when reduction is performed by baking in a nitrogen atmosphere or in a hydrogen-mixed nitrogen atmosphere at 100°C or more and 500°C or less, the use of Rochelle salt tends to make it difficult for divalent metals to be contained in the metal-containing polymer layer.

[0118] In a typical embodiment, the plating solution contains a metal ion source (e.g., a copper ion source) and a reducing agent. For example, the coating may be immersed in the plating solution while air is being bubbled through the solution. The metal ions in the plating solution are reduced by electroless plating, thereby depositing the metal on the surface of the coating, and forming a plated metal layer. If the coating contains a metal oxide, the oxide may or may not be partially or completely reduced by the plating solution during electroless plating, thus forming a plated metal layer on a layer containing the metal oxide and / or metal.

[0119] The metal ion source may exist as ions in the solution. Examples of copper ion sources include CuSO, CuCl, CuCl, CuNO, and Cu(PO), and CuCl and CuSO are preferred from the viewpoint of forming a plating layer with excellent adhesion.

[0120] The metal concentration (e.g., copper concentration) of the plating solution is preferably 1.5 g / L or more, or 1.8 g / L or more, or 2.0 g / L or more from the viewpoint of improving the plating rate, and is preferably 5.0 g / L or less, or 4.0 g / L or less, or 3.5 g / L or less, or 3.0 g / L or less from the viewpoint of uniformity of the plating film. In particular, when wet reduction and plating are combined, the metal concentration of the plating solution is preferably 1.8 g / L or more and 3.5 g / L or less.

[0121] The reducing agent may be one or more selected from the group consisting of potassium tetrahydrogen phosphate, dimethylamine borane, glyoxylic acid, and phosphinic acid. The amount of the reducing agent in the plating solution is preferably 0.1 g / L or more, or 0.5 g / L or more, or 1.0 g / L or more, and preferably 15.0 g / L or less, or 12.0 g / L or less, or 9.0 g / L or less.

[0122] The plating solution may further contain an additional complexing agent in addition to EDTA (ethylenediaminetetraacetic acid) and Rochelle salt. Examples of the additional complexing agent include triethanolamine, ammonium sulfate, citric acid, and glycine. The amount of the additional complexing agent in the plating solution is preferably 5 g / L or more, or 7 g / L or more, or 10 g / L or more, and preferably 50 g / L or less, or 45 g / L or less, or 40 g / L or less. The plating solution may further contain a surfactant, if desired.

[0123] From the viewpoint of good plating growth, the electroless plating solution preferably contains formaldehyde. Because the reducing power of formaldehyde increases with increasing pH, in a typical embodiment, the plating solution contains a pH adjuster. Examples of pH adjusters that can be used include sodium hydroxide, potassium hydroxide, and lithium hydroxide. The pH of the electroless plating solution is preferably 10 or higher from the viewpoint of obtaining good plating growth, and is preferably 14 or lower, or 13.5 or lower, or 13 or lower from the viewpoint of preventing excessive weakening of the polymer substrate. The concentration of the pH adjuster in the electroless plating solution may be an amount useful for controlling the pH within the above range, and in one embodiment, may be 0.01 mol / L or higher and 0.5 mol / L or lower, or 0.01 mol / L or higher and 0.3 mol / L or lower, or 0.01 mol / L or higher and 0.2 mol / L or lower.

[0124] The plating solution may be a commercially available product, such as Thrucup ELC-SP available from Uemura Industries, Ltd., Melplate CU-390 and Melplate CU-5100P available from Meltex Inc., OPC Copper NCA and OPC Copper HFS available from Okuno Chemical Industries, Ltd., C4500 available from Rohm and Haas, PrintganthUPlus available from Atotech, and Cu-510 available from Japan MacDermid.

[0125] The temperature of the electroless plating bath using the plating solution is preferably 25° C. or higher, or 30° C. or higher, or 35° C. or higher, and preferably 80° C. or lower, or 70° C. or lower, or 65° C. or lower, since this allows for faster plating growth. The plating time is preferably 5 minutes or longer, or 10 minutes or longer, and preferably 120 minutes or shorter, or 60 minutes or shorter, or 50 minutes or shorter, or 40 minutes or shorter.

[0126] The sample may be rocked during electroless plating. The sample may be rocked manually or using a rocking device. The sample may be rocked up and down multiple times, approximately once every 30 seconds to 10 minutes. This is expected to remove air bubbles from the sample surface, facilitating uniform plating growth, and to agitate the plating bath, promoting uniform plating growth.

[0127] In one embodiment, electrolytic plating may be performed after electroless plating. A typical electroplating method can be applied to electrolytic plating. For example, an electrode and a conductive substrate to be plated are placed in a solution (plating bath) containing metal ions (e.g., copper ions). Then, a direct current is applied between the electrode and the conductive substrate from an external direct current power supply. In one embodiment, a current can be applied to a metal layer (e.g., a reduced copper layer) on a polymer substrate by connecting a jig (e.g., a clip) connected to one of a pair of electrodes of an external direct current power supply. As a result, metal is precipitated on the surface of the metal layer on the polymer substrate by reduction of the metal ions, forming a plated metal layer.

[0128] Examples of the electrolytic plating bath that can be used include a copper sulfate bath, a copper borofluoride bath, a copper cyanide bath, and a copper pyrophosphate bath. From the viewpoints of safety and productivity, a copper sulfate bath and a copper pyrophosphate bath are preferred.

[0129] As the copper sulfate plating bath, for example, a sulfuric acid copper sulfate plating bath containing copper sulfate pentahydrate, sulfuric acid, and chlorine is preferably used. The concentration of copper sulfate pentahydrate in the copper sulfate plating bath is preferably 50 g / L or more, or 100 g / L or more, and preferably 300 g / L or less, or 200 g / L or less. The concentration of sulfuric acid is preferably 40 g / L or more, or 80 g / L or more, and preferably 160 g / L or less, or 120 g / L or less. The solvent for the plating bath is usually water. The temperature of the plating bath is preferably 20°C or more, or 30°C or more, and preferably 60°C or less, or 50°C or less. The current density during electrolysis is preferably 1 A / dm 2 or more, or 2 A / dm 2 or more, preferably 15 A / dm 2 or less than 10 A / dm 2 The following is the result.

[0130] A suitable copper pyrophosphate plating bath is, for example, a plating bath containing copper pyrophosphate and potassium pyrophosphate. The concentration of copper pyrophosphate in the copper pyrophosphate plating bath is preferably 60 g / L or more, or 70 g / L or more, and preferably 110 g / L or less, or 90 g / L or less. The concentration of potassium pyrophosphate is preferably 240 g / L or more, or 300 g / L or more, and preferably 470 g / L or less, or 400 g / L or less. The solvent for the plating bath is usually water. The pH of the plating bath is preferably 8.0 or more, or 8.2 or more, and preferably 9.0 or less, or 8.8 or less. Ammonia water or the like may be added to adjust the pH value. The temperature of the plating bath is preferably 20°C or more, or 30°C or more, and preferably 60°C or less, or 50°C or less. The current density during electrolysis is preferably 0.5 A / dm 2 or more, or 1 A / dm 2 or more, preferably 10 A / dm 2 or less, or 7 A / dm 2 The plating bath for electrolytic plating may further contain a surfactant.

[0131] From the viewpoint of obtaining good conductivity, the thickness of the plating layer is preferably 0.1 μm or more, or 0.5 μm or more, or 1.0 μm or more, and preferably 1000 μm or less, or 500 μm or less, or 100 μm or less, or 50 μm or less, or 10 μm or less, or 5 μm or less.

[0132] The metal layer may be formed by sputtering. The sputtering conditions, i.e., the pressure during sputtering, the power input during film formation, the distance or angle to the substrate, and the temperature during sputtering, can be adjusted as appropriate.

[0133] <Metal Wiring Manufacturing Apparatus> The laminate of this embodiment can be manufactured using, for example, the following apparatus. Fig. 3 is a schematic diagram of a metal wiring manufacturing apparatus used in one aspect of the present invention. The metal wiring manufacturing apparatus 10 includes a structure holding unit 101 and an optical oscillator 102. The metal wiring manufacturing apparatus 10 may also include an inert gas generator 103, an optical beam scanning unit 104, a speed control unit 105, and / or a computer 106.

[0134] <Structure-holding section> In one embodiment, the structure-holding section 101 is a sample chamber. In one embodiment, the structure has a substrate and a coating film disposed on the substrate. The structure according to one embodiment is a laminate of a polymer substrate and an oxide-containing film disposed on the polymer substrate. The sample chamber may have a window. The sample chamber may have an inert gas inlet, and may be configured, for example, so that an inert gas generated by an inert gas generator 103 is introduced into the sample chamber via the inert gas inlet.

[0135] <Light Beam Oscillator> The light beam oscillator 102 is configured to emit a light beam at a desired wavelength. In a typical embodiment, the light beam is a laser beam. When using laser beam as the light beam, a laser light source such as YAG (yttrium aluminum garnet), YVO (yttrium vanadate), Yb (ytterbium), a semiconductor (GaAs, GaAlAs, GaInAs), or carbon dioxide gas may be used. The laser beam may be not only a fundamental wave but also a harmonic wave extracted as necessary. LED light may also be used as the light beam. The light beam oscillator 102 may be equipped with a cooling device or the like.

[0136] <Light Beam Scanning Unit> The light beam scanning unit 104 scans the light beam L emitted from the light beam oscillator 102. FIG. 3 shows an example in which the light beam scanning unit 104 is a galvanometer scanner. The galvanometer scanner serving as the light beam scanning unit 104 includes an X-axis galvanometer mirror 104a, an X-axis galvanometer motor 104b, a Y-axis galvanometer mirror 104c, and a Y-axis galvanometer motor 104d. The galvanometer scanner may include an fθ lens (not shown), a Z-axis adjustment drive lens (not shown), and the like. The X-axis galvanometer motor 104b and the Y-axis galvanometer motor 104d are electrically connected to a speed control unit 105 (e.g., a scanner control unit).

[0137] The galvanometer scanner is configured to be able to control the rotation angle and rotation speed of the X-axis galvanometer motor 104b and the Y-axis galvanometer motor 104d in accordance with control signals from a speed control unit 105. The speed control unit 105 is controlled by a computer 106. The light beam L is scanned by the light beam scanning unit 104 and irradiated onto the surface of the coating film 12 formed on the substrate 11.

[0138] In the above, a galvanometer scanner is exemplified as the light beam scanning unit 104, but a light beam scanning unit other than a galvanometer scanner can also be used. For example, instead of a galvanometer scanner, the light beam scanning unit 104 may use an X-Y stage as a mounting table that can move the substrate 11 on which the coating film 12 is formed in both the X-axis direction and the Y-axis direction, and move the substrate 11 instead of moving the irradiation point P of the laser light L.

[0139] The light beam scanning unit 104 (galvanometer scanner) shown in FIG. 3 uses an X-axis galvanometer mirror 104a and a Y-axis galvanometer mirror 104c for movement in the X-axis and Y-axis directions, respectively. However, it is also possible to use a galvanometer mirror for either the X-axis or the Y-axis, for example, to use a galvanometer mirror for movement only in the X-axis direction and a motor of a mounting table (not shown) on which the substrate 11 is placed for movement in the Y-axis direction.

[0140] Scanning speed control in the metal wiring manufacturing apparatus 10 can be performed, for example, as follows. First, scanning data (coordinate data) indicating the desired shape, position, and size of the metal wiring pattern is input to the speed control unit 105. The scanner control unit serving as the speed control unit 105 calculates the scanning line length (L) (unit: mm) from the length of the pattern along the X-axis direction based on the scanning data. Next, based on the calculated scanning line length (L), the scanner control unit calculates the speed (V) (unit: mm / sec) at which the laser light is scanned (hereinafter referred to as scanning speed) so as to achieve a predetermined scanning period (F) (unit: Hz) (e.g., 15 Hz) using the following formula: Scanning speed (V) = scanning period (F) x scanning line length (L)

[0141] Next, the scanner control unit causes the galvano scanner serving as the light beam scanning unit 104 to move the irradiation point P of the laser light L in the X-axis direction according to the scanning speed calculated in this manner, and executes one scan. Thereafter, the scanner control unit causes the galvano scanner to move the irradiation point P of the laser light L in the Y-axis direction. As described above, the scanning speed (V) of the laser light L can be set based on the length (L) of the scan line so that the scanning period (F) is the same at any position within the coating film 12.

[0142] <Substrate with Metal Wiring> One aspect of the present invention provides a laminate that is a substrate with metal wiring, comprising a polymer substrate and metal wiring on the polymer substrate. In one aspect, the polymer substrate has a polymer layer and a metal-containing polymer layer. In a typical aspect, the metal wiring and the metal-containing polymer layer are in contact with each other, and the metal-containing polymer layer and the polymer layer are in contact with each other. The substrate with metal wiring is suitably applied to, for example, a circuit board such as a printed wiring board. This type of circuit board generally has a structure in which conductive wiring is provided on a substrate. That is, in the substrate with metal wiring according to one aspect, a metal layer pattern is arranged as metal wiring on the polymer substrate (more specifically, on the metal-containing polymer layer of a polymer substrate having a polymer layer and a metal-containing polymer layer). Multiple metal layer patterns may be arranged on the substrate, and the shape and size thereof may be selected as desired.

[0143] In one embodiment, in infrared absorption spectrum measurement of the polymer substrate, the minimum value of the ratio (IR1) / (IR2) of the peak intensity (IR1) of the first peak derived from the first structure in the main chain of the polymer constituting the polymer substrate to the peak intensity (IR2) of the second peak derived from the second structure in the main chain is within the range described above as the ratio (IR1) / (IR2) of the metal-containing polymer layer and the polymer layer.

[0144] Other Embodiments The present invention is not limited to the above-described embodiments and can be implemented in various modifications within the scope of the present invention. For example, the laminate may further include other layers in addition to the metal layer, the metal-containing polymer layer, and the polymer layer. Furthermore, for example, the polymer layer may be a molded body having a thickness of more than 1000 μm. The molded body may be a plate-like body, a three-dimensional object of various shapes, or the like.

[0145] The present disclosure also includes the following items. <Aspect 1> [Item 1] A laminate including a metal layer, a metal-containing polymer layer, and a polymer layer arranged in this order, wherein the metal layer includes a first metal layer and a second metal layer disposed between the first metal layer and the metal-containing polymer layer, wherein the first metal layer, the second metal layer, and the metal-containing polymer layer contain the same metal, wherein the thickness of the first metal layer is 0.1 μm to 1000 μm, the thickness of the second metal layer is 0.01 μm to 10 μm, the thickness of the metal-containing polymer layer is 0.04 μm to 10 μm, and the thickness of the polymer layer is 1.0 μm to 1000 μm. [Item 2] The laminate according to item 1, wherein the second metal layer contains carbon. [Item 3] The laminate according to item 1 or 2, wherein the second metal layer contains carbon at 0.1 atomic % or more and 15 atomic % or less. [Item 4] The laminate according to any one of items 1 to 3, wherein the same type of metal is copper. [Item 5] The laminate according to any one of items 1 to 4, wherein a pattern of the metal layer is formed on the metal-containing polymer layer. [Item 6] The laminate according to any one of items 1 to 5, wherein the metal-containing polymer layer contains sodium. [Item 7] The laminate according to any one of items 1 to 6, wherein the metal-containing polymer layer contains sodium at 0.1 atomic % or more and 10 atomic % or less, and a metal at 1 atomic % or more and 10 atomic % or less. [Item 8] The laminate according to any one of items 1 to 7, wherein the polymer constituting the metal-containing polymer layer and the polymer constituting the polymer layer are nitrogen-containing polymers, and the laminate contains a metal chemically bonded to a nitrogen atom. [Item 9] The laminate according to any one of items 1 to 8, wherein the metal-containing polymer layer contains a zero-valent or monovalent metal. [Item 10] The laminate according to any one of items 1 to 9, wherein the second metal layer is a layer formed by reducing a layer containing copper oxide. [Item 11] The laminate according to any one of items 1 to 10, wherein the metal-containing polymer layer is the metal-containing polyimide layer, and the polymer layer is a polyimide layer.[Item 12] The laminate according to any one of items 1 to 11, wherein, in infrared absorption spectroscopy, the minimum value of the ratio (IR1) / (IR2) of the peak intensity of a first peak derived from a first structure in the main chain (IR1) to the peak intensity of a second peak derived from a second structure in the main chain (IR2) for the metal-containing polymer layer and the polymer constituting the polymer layer is 0.2 or more and 1.5 or less. [Item 13] The laminate according to any one of items 1 to 12, which is used as a component of an electronic circuit board. [Item 14] A method for producing the laminate according to any one of items 1 to 12, comprising: a coating step of coating a metal oxide on a polymer substrate; and a reduction step of reducing the metal oxide. [Item 15] The method according to item 14, wherein the reduction is carried out by laser light irradiation. [Item 16] The method according to item 14 or 15, further comprising an electroless metal plating step. [Item 17] The method according to item 16, wherein the electroless metal plating step is carried out after the reduction step. [Item 18] A method for manufacturing a laminate, comprising the steps of: forming a first metal layer having a thickness of 0.1 μm or more and 1000 μm or less; forming a second metal layer having a thickness of 0.01 μm or more and 10 μm or less; forming a metal-containing polymer layer having a thickness of 0.04 μm or more and 10 μm or less; and forming a polymer layer having a thickness of 1.0 μm or more and 1000 μm or less, wherein the first metal layer, the second metal layer, the metal-containing polymer layer, and the polymer layer are arranged in this order, and the first metal layer, the second metal layer, and the metal-containing polymer layer contain the same type of metal. [Item 19] The method for producing a laminate according to Item 18, wherein the step of forming the second metal layer comprises: a coating step of applying a dispersion containing metal particles and / or metal oxide particles onto a substrate to form a dispersion layer; a drying step of drying the dispersion layer to form a dry coating film on the substrate; and a step of heating the dry coating film to form the second metal layer.[Item 20] The method for manufacturing a laminate according to item 18 or 19, wherein the step of forming the second metal layer comprises: a coating step of applying a dispersion containing metal particles and / or metal oxide particles onto a substrate to form a dispersion layer; a drying step of drying the dispersion layer to form a dry coating film on the substrate; and a step of irradiating with a laser to bake the dried coating film to form the second metal layer. [Item 21] The method for manufacturing a laminate according to item 20, wherein the step of forming the first metal layer comprises: forming the first metal layer by immersing the second metal layer in a plating solution. [Item 22] The method for manufacturing a laminate according to item 21, wherein the plating solution has a pH of 10 or more and 14 or less. [Item 23] The method for manufacturing a laminate according to any one of items 19 to 22, wherein the metal particles and / or metal oxide particles are copper particles and / or copper oxide particles.

[0146] Aspect 2: [Item 1] A substrate with metal wiring, comprising a polymer substrate and metal wiring on the polymer substrate, wherein, in infrared absorption spectrum measurement of the polymer substrate, the minimum value of the ratio (IR1) / (IR2) of the peak intensity (IR1) of a first peak derived from a first structure in a main chain of a polymer constituting the polymer substrate to the peak intensity (IR2) of a second peak derived from a second structure in the main chain is 0.2 or more and 1.5 or less. [Item 2] The polymer is a polyimide, the first structure is an imide ring, and the first peak has a peak intensity at 1702 cm －１ ~1722cm －１ the second structure is a benzene ring, and the second peak is at 1494 cm －１ ~1514cm －１The substrate with metal wiring according to item 1, wherein the metal wiring is copper wiring. [Item 3] The substrate with metal wiring according to item 1 or 2, wherein the metal wiring is copper wiring. [Item 4] The substrate with metal wiring according to any one of items 1 to 3, wherein the metal wiring comprises carbon. [Item 5] The substrate with metal wiring according to any one of items 1 to 4, wherein the metal wiring comprises cuprous oxide. [Item 6] The substrate with metal wiring according to any one of items 1 to 5, wherein the polymer substrate and the metal wiring comprise the same metal, and the polymer substrate comprises the same metal in a zero-valent and / or monovalent state. [Item 7] The substrate with metal wiring according to any one of items 1 to 6, wherein the metal wiring has a porosity of 0.1 vol % to 30 vol % in a region from the polymer substrate side to a depth of 1 nm to 500 nm. [Item 8] A method for producing a substrate with metal wiring according to any one of items 1 to 7, comprising: a coating step of coating a metal oxide on a polymer substrate; and a reduction step of reducing the metal oxide. [Item 9] The method according to item 8, wherein the reduction is carried out by laser light irradiation. [Item 10] The method according to item 8 or 9, further comprising an electroless metal plating step. [Item 11] The method according to item 10, wherein the electroless metal plating step is carried out after the reduction step.

[0147] <<Aspect 3>> [Item 1] A laminate comprising a metal layer, a metal-containing polymer layer, and a polymer layer arranged in this order, wherein the metal layer and the metal-containing polymer layer contain the same type of metal, the polymer constituting the metal-containing polymer layer and the polymer constituting the polymer layer are nitrogen-containing polymers, and the metal-containing polymer layer contains a metal chemically bonded to a nitrogen atom. [Item 2] The laminate according to Item 1, wherein the metal-containing polymer layer contains a zero-valent and / or monovalent metal. [Item 3] The laminate according to Item 1 or 2, wherein the metal-containing polymer layer contains a zero-valent and monovalent metal. [Item 4] The laminate according to any one of Items 1 to 3, wherein the same type of metal contains copper, and the metal chemically bonded to the nitrogen atom contains monovalent copper. [Item 5] The nitrogen-containing polymer is a polyimide, and infrared absorption spectroscopy of the metal-containing polymer layer and the polymer layer reveals a peak at 1702 cm-1 ~1722cm -1 and the peak intensity (IRI) of the first peak in the range of 1494 cm -1 ~1514cm -1 The laminate according to any one of items 1 to 4, wherein the ratio (IR1) / (IR2) of the peak intensity of the first peak to the peak intensity (IR2) of the second peak in the range of 0.2 to 1.5 is 0.2 or more and 1.5 or less. [Item 6] The laminate according to any one of items 1 to 5, wherein a pattern of the metal layer is disposed on the metal-containing polymer layer. [Item 7] A method for producing the laminate according to any one of items 1 to 6, comprising: a coating step of coating a metal oxide on a polymer substrate; and a reduction step of reducing the metal oxide. [Item 8] The method according to item 7, wherein the reduction is carried out by laser light irradiation. [Item 9] The method according to item 7 or 8, further comprising an electroless metal plating step. [Item 10] The method according to item 9, wherein the electroless metal plating step is carried out after the reduction step.

[0148] <<Aspect 4>> [Item 1] A laminate comprising a metal layer, a metal-containing polymer layer, and a polymer layer arranged in this order, wherein the metal layer and the metal-containing polymer layer contain the same type of metal, the metal layer has a thickness of 0.1 μm to 1000 μm, the metal-containing polymer layer has a thickness of 0.04 μm to 10 μm, and the polymer layer has a thickness of 1 μm to 1000 μm, and when observed in a cross section in the thickness direction of the laminate, the ratio (L2) / (L1) of the length (L2) of the boundary line between the metal layer and the metal-containing polymer layer to the in-plane length (L1) of the laminate is 1.0 to 2.0. [Item 2] The laminate according to Item 1, wherein the same type of metal is copper. [Item 3] The laminate according to Item 1 or 2, wherein a pattern of the metal layer is disposed on the metal-containing polymer layer. [Item 4] The laminate according to any one of items 1 to 3, wherein the metal-containing polymer layer contains 0.1 atomic % to 10 atomic % of sodium and 1 atomic % to 10 atomic % of metal. [Item 5] The laminate according to any one of items 1 to 4, wherein the polymer constituting the metal-containing polymer layer and the polymer constituting the polymer layer are nitrogen-containing polymers, and the laminate contains a metal chemically bonded to a nitrogen atom. [Item 6] A method for producing the laminate according to any one of items 1 to 5, comprising: a coating step of coating a metal oxide on a polymer substrate; and a reduction step of reducing the metal oxide. [Item 7] The method according to item 6, wherein the reduction is performed by laser light irradiation. [Item 8] The method according to item 6 or 7, further comprising an electroless metal plating step. [Item 9] The method according to item 8, wherein the electroless metal plating step is performed after the reduction step.

[0149] The present embodiment will be described in more detail below with reference to examples and reference examples. However, the present embodiment is not limited to the following examples. Unless otherwise specified, the steps, treatments, operations, etc. described below were carried out at room temperature. The room temperature was, for example, 25°C.

[0150] <<Production of Laminate>> [Example 1] A laminate was produced by the following method, and various evaluations were carried out.

[0151] <Dispersion> A solvent consisting of 800 g of ion-exchanged water and 400 g of 1,2-propylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.), 80 g of copper (II) acetate monohydrate (manufactured by Wako Pure Chemical Industries, Ltd.), and 20 g of hydrazine hydrate (manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and stirred under a nitrogen atmosphere, followed by centrifugation to separate the supernatant and precipitate.

[0152] 2.8 g of the obtained precipitate was mixed with 0.4 g of DISPERBYK-145 (trade name, manufactured by BYK-Chemie) as a phosphorus-containing organic compound and 6.6 g of ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersion medium, and the precipitate was dispersed using a homogenizer under a nitrogen atmosphere. The supernatant and precipitate were then separated by centrifugation, and the precipitate was collected. The precipitate was diluted with ethanol and dispersed using a homogenizer under a nitrogen atmosphere.

[0153] The above-mentioned centrifugation operation (concentration operation) and the above-mentioned dispersion operation (dilution operation) were repeated to obtain a dispersion containing cuprous oxide particles. The cuprous oxide particles contained cuprous oxide (copper(I) oxide). The average particle diameter was 15 nm. The average particle diameter was measured by the cumulant method using an FPAR-1000 manufactured by Otsuka Electronics Co., Ltd. (the same applies hereinafter).

[0154] The final composition of the dispersion was 2.8 g of precipitate, 0.4 g of DISPERBYK-145, 6.6 g of ethanol, and 0.01 g of hydrazine hydrate.

[0155] <Polymer substrate> Kapton (trademark) 100H (manufactured by DuPont-Toray Co., Ltd.) with dimensions of 70 mm width x 70 mm depth x 0.025 mm thickness was prepared as a polyimide substrate (polyimide film). The surface of this substrate was subjected to UV ozone treatment for 3 minutes, and then 1 ml of the dispersion was dropped onto the surface. The dropped dispersion was spin-coated onto the substrate (1400 rpm x 300 seconds) and dried at room temperature for 10 minutes. This was then further dried at 90°C for 2 hours. This yielded a sample in which a coating film was formed on the substrate.

[0156] <Metal Layer (Second Metal Layer)> A metal wiring manufacturing apparatus 10 having the configuration shown in FIG. 3 was used. First, the sample was placed in the structure holder 101 (sample chamber). The sample chamber was left open (in the atmosphere). Then, using a galvanometer scanner (as the beam scanning unit 104), the coating film in the sample chamber was irradiated with laser light (center wavelength 355 nm, frequency 300 kHz, pulse output 17 mW, and spot diameter 18 μm) while moving the focal position at a maximum speed of 10 mm / s. The laser light was then moved 20 mm in the scanning direction (first irradiation), then 10 μm in a direction perpendicular to the scanning direction, and then again in the scanning direction at a maximum speed of 10 mm / s (second irradiation). This operation was repeated, and the laser light was scanned while moving in 10 μm increments in the direction perpendicular to the scanning direction. As a result, a copper-containing film (second metal layer) measuring 20 mm in length and 10 mm in width was formed on the polyimide substrate.

[0157] <Metal Layer (First Metal Layer)> Next, an electroless plating solution containing formaldehyde and sodium hydroxide (manufactured by Okuno Chemical Industries Co., Ltd., product name: OPC Copper NCA) (containing 2.2 g / L of formaldehyde) was heated to 60°C. The sample was then immersed in the heated plating solution for 30 minutes. The pH of the plating solution was adjusted to 12.8, and the sodium hydroxide concentration was adjusted to 0.17 mol / L. During immersion, the sample was shaken up and down (shaking operation) once every 3 minutes. After immersion for 30 minutes, the sample was removed and washed with water. This formed a plating layer (first metal layer) on the copper-containing film (second metal layer). Through the above procedure, a laminate according to Example 1 was obtained.

[0158] [Example 2] <Dispersion> A solvent consisting of 30,240 g of water and 13,976 g of 1,2-propylene glycol (manufactured by Asahi Glass Co., Ltd.), 3,224 g of copper (II) acetate monohydrate (manufactured by Nippon Chemical Industry Co., Ltd.), and 940 g of hydrazine hydrate (manufactured by Nippon Finechem Co., Ltd.) were mixed and stirred under a nitrogen atmosphere, followed by centrifugation to separate the supernatant and precipitate.

[0159] Additionally, 72 g of DISPERBYK-145 (trade name, manufactured by BYK-Chemie) (BYK-118) as a phosphorus-containing organic compound and 764 g of 1-heptanol (manufactured by Toyo Gosei Co., Ltd.) as a dispersion medium were mixed to obtain a mixed solution. 345 g of the precipitate obtained above and 794 g of the mixed solution were mixed, and the precipitate was dispersed using a homogenizer under a nitrogen atmosphere. This resulted in a dispersion containing cuprous oxide particles. Such cuprous oxide particles contain cuprous oxide (copper(I) oxide). Furthermore, 1063 g of the above dispersion, 5 g of DISPERBYK-145, and 82 g of 1-heptanol were mixed, and the precipitate was dispersed using a homogenizer under a nitrogen atmosphere to obtain the desired dispersion.

[0160] The final composition of the dispersion contained 0.2% by mass of hydrazine. The solid residue (cuprous oxide particles) after heating the dispersion at atmospheric pressure and 60°C for 4.5 hours was 26.1% by mass. The average particle size of the cuprous oxide particles was 30 nm.

[0161] <Polymer Substrate> Kapton (trademark) 100H (manufactured by DuPont-Toray Co., Ltd.) measuring 70 mm wide x 70 mm deep x 0.025 mm thick was prepared as a polyimide substrate (polyimide film). The surface of this substrate was subjected to UV ozone treatment for 3 minutes, and then the dispersion was used as ink and printed on the surface using an inkjet printer (manufactured by Fujifilm Corporation, Dimatix DMP-2835). The head was a Samba cartridge (discharging 2.4 pl), the voltage was 40 V, and the frequency was 25 kHz. Here, a 50 mm x 50 mm pattern was drawn. After printing, the substrate was dried at 60°C for 30 minutes. This yielded a sample in which a coating film was formed on the substrate.

[0162] <Metal Layer (Second Metal Layer)> The above sample was baked at 300° C. for 1 hour in a nitrogen atmosphere to form a copper-containing film (second metal layer) on the polyimide substrate.

[0163] <Metal Layer (First Metal Layer)> Next, an electroless plating solution containing formaldehyde and sodium hydroxide (manufactured by Okuno Chemical Industries Co., Ltd., product name: OPC Copper HFS) (containing 2.5 g / L of formaldehyde) was heated to 60°C. The sample was then immersed in the heated plating solution for 120 minutes. The pH of the plating solution was adjusted to 12.6, and the sodium hydroxide concentration was adjusted to 0.05 mol / L. During immersion, the sample was shaken vertically (shaking operation) once every 3 minutes. After immersion for 120 minutes, the sample was removed and washed with water. This formed a plating layer (first metal layer) on the copper-containing film (second metal layer). Through the above procedure, a laminate according to Example 2 was obtained.

[0164] Reference Example 1 A laminate was obtained in the same manner as in Example 1, and then heated at 150° C. for 240 hours to obtain a laminate according to Reference Example 1.

[0165] [Example 3] A laminate according to Example 3 was obtained by following the same procedures as in Example 2 for the <dispersion>, <polymer substrate>, and <metal (second metal layer)>, and the same procedures as in Example 1 for the <metal layer (first metal layer)>.

[0166] [Example 4] <Dispersion> A solvent consisting of 800 g of ion-exchanged water and 400 g of 1,2-propylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.), 80 g of copper (II) acetate monohydrate (manufactured by Wako Pure Chemical Industries, Ltd.), and 20 g of hydrazine hydrate (manufactured by Wako Pure Chemical Industries, Ltd.) were mixed and stirred under a nitrogen atmosphere, followed by centrifugation to separate the supernatant and precipitate.

[0167] 4.4 g of the obtained precipitate was mixed with 0.4 g of DISPERBYK-145 (trade name, manufactured by BYK-Chemie) as a phosphorus-containing organic compound and 5.0 g of ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) as a dispersion medium, and the precipitate was dispersed using a homogenizer under a nitrogen atmosphere. The supernatant and precipitate were then separated by centrifugation, and the precipitate was collected. The precipitate was diluted with ethanol and dispersed using a homogenizer under a nitrogen atmosphere.

[0168] The above-mentioned centrifugation (concentration) and dispersion (dilution) procedures were repeated to obtain a dispersion containing cuprous oxide particles. The cuprous oxide particles contained cuprous oxide (copper(I) oxide). The average particle size was 15 nm.

[0169] The final composition of the dispersion was 4.4 g of precipitate, 0.4 g of DISPERBYK-145, 6.6 g of ethanol, and 0.01 g of hydrazine hydrate.

[0170] <Polymer substrate> A Kapton (trademark) 500H (manufactured by DuPont-Toray Co., Ltd.) measuring 70 mm wide x 70 mm deep x 0.125 mm thick was prepared as a polyimide substrate (polyimide film). The surface of this substrate was subjected to UV ozone treatment for 3 minutes, and then 1 ml of the dispersion was dropped onto the surface. The dropped dispersion was spin-coated onto the substrate (500 rpm x 300 seconds) and dried at room temperature for 10 minutes. This was then further dried at 90°C for 2 hours. This yielded a sample in which a coating film was formed on the substrate.

[0171] <Metal Layer (Second Metal Layer)> A metal wiring manufacturing apparatus 10 having the configuration shown in FIG. 3 was used. First, the sample was placed in the structure holder 101 (sample chamber). Nitrogen gas was supplied to the sample chamber at 1.0 L / min. Then, using a galvanometer scanner (as the beam scanning unit 104), the coating film in the sample chamber was irradiated with laser light (center wavelength 355 nm, frequency 300 kHz, pulse output 110 mW, and spot diameter 18 μm) while moving the focal position at a maximum speed of 5 mm / sec. The laser light was then moved 20 mm in the scanning direction (first irradiation), then 30 μm in a direction perpendicular to the scanning direction, and then again in the scanning direction at a maximum speed of 5 mm / sec (second irradiation). This operation was repeated, and the laser light was scanned while moving 30 μm increments in the direction perpendicular to the scanning direction. This resulted in the formation of a copper-containing film (second metal layer) measuring 20 mm in length and 10 mm in width on the polyimide substrate.

[0172] <Metal Layer (First Metal Layer)> The same procedure as in Example 1 was carried out.

[0173] Example 5 A laminate according to Example 5 was obtained in the same manner as in Example 2, except that the procedure for forming the metal layer (first metal layer) was not performed (i.e., the first metal layer was not formed).

[0174] Example 6 A laminate according to Example 6 was obtained in the same manner as in Example 1, except that the procedure for forming the metal layer (first metal layer) was not carried out (i.e., the first metal layer was not formed).

[0175] Comparative Example 1 Dispersion A dispersion containing cuprous oxide particles was obtained in the same manner as in Example 1. The cuprous oxide particles contained cuprous oxide (copper (I) oxide). 8.4 g of copper powder 1400YP (manufactured by Mitsui Mining & Smelting Co., Ltd.) was further added, and the mixture was stirred with a stirrer to obtain the desired dispersion.

[0176] <Polymer Substrate> An Upilex (trademark) S (manufactured by UBE) with dimensions of 70 mm width x 70 mm depth x 0.025 mm thickness was prepared as a polyimide substrate (polyimide film). After UV ozone treatment was performed on the surface of this substrate for 3 minutes, 1 ml of the dispersion was dropped onto the surface. The dropped dispersion was spin-coated onto the substrate (1400 rpm x 30 seconds) and dried at room temperature for 10 minutes. This was followed by further drying at 90°C for 2 hours. Therefore, a reduction step was not performed. This resulted in a sample in which a coating film was formed on the substrate.

[0177] <First Metal Layer> Next, an electroless plating solution containing formaldehyde and sodium hydroxide (manufactured by Okuno Chemical Industries Co., Ltd., product name: OPC Copper NCA) (containing 2.2 g / L of formaldehyde) was heated to 60°C. Then, the sample was immersed in the heated plating solution for 30 minutes. The pH of the plating solution was adjusted to 12.8, and the sodium hydroxide concentration was adjusted to 0.17 mol / L. During the immersion, the sample was not shaken up and down once every 3 minutes (rocking operation). After the 30-minute immersion treatment, the sample was taken out and washed with water. Through the above procedure, a laminate according to Comparative Example 1 was obtained.

[0178] <Evaluation> The laminates according to the Examples, Comparative Examples, and Reference Examples were evaluated by the following methods.

[0179] <Evaluation of Resistance Value> The resistance value of the laminate was measured using a four-terminal, four-probe method. The pattern size of the metal layers (first metal layer and second metal layer) in the laminate and the film thickness of the metal layers were input into a Loresta GP MCP-T600 (manufactured by Nitto Seiko Analytech Co., Ltd.), and the volume resistivity was measured. The evaluation criteria were as follows: a volume resistivity of less than 10 μΩcm was rated "A," and a volume resistivity of 10 μΩcm or more was rated "B." Note that Reference Example 1 is an example for evaluating the effect of the metal concentration in the metal-containing polymer layer; however, an oxide film formed on the first metal layer made it impossible to evaluate the resistance value, so evaluation was not performed. The evaluation results are shown in the table below.

[0180] <Evaluation of Adhesion> Adhesion was evaluated by a tape peeling test. A tape with an adhesion strength of 0.4 N / mm (Nichiban Co., Ltd., product name: Cellotape (registered trademark) CT-18) was applied to the surface of the laminate, and then immediately peeled off in one go so that the angle between the surface and the tape was 60 degrees. If peeling did not occur, a tape with an adhesion strength of 1.5 N / mm (3M Japan Co., Ltd., product name: Scotch Strong Single-Sided Tape #879) was applied to the surface of the laminate, and then immediately peeled off in one go so that the angle between the surface and the tape was 60 degrees. The evaluation criteria were as follows: if the metal layer did not peel off from the laminate with the 1.5 N / mm tape, it was evaluated as "A"; if the metal layer did not peel off with the 0.4 N / mm tape but peeled off with the 1.5 N / mm tape, it was evaluated as "B"; and if the metal layer peeled off with the 0.4 N / mm tape, it was evaluated as "C". The evaluation results are shown in the table below.

[0181] The presence or absence of "peeling" was confirmed by visually observing the surface of the laminate after the tape was peeled off and the adhesive surface of the peeled tape. When at least partial peeling of the metal layer was observed, it was evaluated as "peeling present."

[0182] <Evaluation of Adhesion Reproducibility> The above <Evaluation of Adhesion> was performed at four different locations within the laminate. Specifically, for Examples 2, 3, and 5 and Comparative Example 1, four 20 mm x 20 mm test pieces were cut from the laminate at 5 mm intervals. For Examples 1, 4, and 6 and Reference Example 1, because the size of the laminate was smaller than the above test pieces, four 20 mm x 10 mm laminates were prepared and similar evaluations were performed on each of the four pieces. The evaluation criteria were as follows: "A" was given when results similar to those in the <Evaluation of Adhesion> column were obtained at all four locations, and "B" was given when results similar to those in the <Evaluation of Adhesion> column were obtained at three or fewer locations. The evaluation results are shown in the table below. Excellent adhesion reproducibility means that the laminate can reliably exhibit good adhesion, which also means that the reliability of electronic devices obtained using the laminate can be easily improved.

[0183] <Thickness, porosity, element concentration, and interface roughness> The following samples were evaluated using a scanning transmission electron microscope (STEM). Each measurement was performed five times at different measurement sites, and the average value of the five measurements was used.

[0184] (Sample Preparation) A cross section in the thickness direction of the laminate was exposed and processed by a microsampling method using a focused ion beam (FIB). To protect the cross section, a naphthalene film approximately 200 nm thick was formed by plasma CVD. Furthermore, a platinum (Pt) film was formed by sputtering to impart conductivity. A portion of the sample was then cut out using the FIB to obtain a thin section sample.

[0185] (Thickness of Metal Layer) The above thin sample was subjected to STEM observation. The observation conditions were as follows: Measuring device: HD-2300A (manufactured by Hitachi Corporation) Measurement conditions: Acceleration voltage 200 kV Measurement magnification: Magnification that covers the entire thickness of the metal layer in the field of view (for example, 50,000 times) Observation mode: Secondary electron image mode

[0186] In the observed image, both surfaces of the laminate and the boundary between the metal layer and the metal-containing polymer layer were distinguishable. Therefore, the image was analyzed using the image processing software "ImageJ" from the National Institutes of Health (NIH). The image was converted to 8 bits using ImageJ, and then smoothed using the Smooth function and filtered using Median Filter (Radius; 2 pixels). The entire metal layer was then selected and binarized using Threshold. The threshold for the binarization process was determined using "Default," a judgment method built into the software. The voids were identified as black areas. The area percentage (unit: area%) of these black areas was calculated using "Analyze Particle," and this value was simulated as the porosity (unit: volume%).

[0187] In the binarized image, the portion corresponding to the upper surface of the metal layer (the exposed surface of the laminate) was observed to be approximately linear. A line segment was drawn along this approximately linear line, and a rectangle with this line segment as its upper edge was designated. The left and right edges of the rectangle were designated to extend from the exposed surface of the laminate to a predetermined depth toward the polyimide substrate. The area ratio of the black portion within the rectangle was calculated as the porosity. While keeping the upper edge fixed, the left and right edges were increased, and the porosity calculation was repeated. The bottom edge of the rectangle was recorded when the porosity value reached 0.5 volume %. The length of the left edge of the rectangle at this time was defined as the thickness of the first metal layer. The porosity calculation was further repeated, and the length of the left edge of the rectangle when the bottom edge reached the boundary between the metal layer and the metal-containing polymer layer was defined as the total thickness of the metal layer. Note that since the boundary between the metal layer and the metal-containing polymer layer had an uneven shape, the imaginary boundary line, which is the line segment connecting the intersections of both ends of the binarized image and the boundary, was considered to be the boundary between the metal layer and the metal-containing polymer layer. The value obtained by subtracting the thickness of the first metal layer from the total thickness of the metal layers was taken as the thickness of the second metal layer.

[0188] The total thickness of the metal-containing polymer layer and the polymer layer was measured on the secondary electron image.

[0189] (Thickness of Metal-Containing Polymer Layer) The above thin sample was subjected to energy dispersive X-ray analysis (EDX analysis) using STEM to obtain spectrum image data. The measurement conditions were as follows. Measurement device: HD-2300A (manufactured by Hitachi Corporation) Measurement conditions: Acceleration voltage 200 kV Measurement magnification: 50,000x STEM-EDX: Octane T plus (EDAX) EDX detector: Apollo XLT2 SUTW Measurement target elements: copper, carbon, nitrogen, oxygen, sodium

[0190] Line analysis was performed in the thickness direction of the laminate from the metal layer side toward the polymer layer side. A spectrum image was obtained showing a transition from a high copper concentration region (corresponding to the metal layer) through a medium copper concentration region (corresponding to the metal-containing polymer layer) to a low copper concentration region (corresponding to the polymer layer). The medium copper concentration region was present in each example. This confirmed the presence of a metal-containing polymer layer. The transition from the high copper concentration region to the medium copper concentration region was steep, and this point was determined to be the boundary between the metal layer and the metal-containing polymer layer. Meanwhile, the boundary between the medium copper concentration region and the low copper concentration region was determined to be the boundary between these regions (and therefore the boundary between the metal-containing polymer layer and the polymer layer) at a point where the copper concentration reached 1 atomic %. The thickness from the boundary between the metal layer and the metal-containing polymer layer to the boundary between the metal-containing polymer layer and the polymer layer was determined to be the thickness of the metal-containing polymer layer.

[0191] (Thickness of Polymer Layer) The thickness of the polymer layer was determined as the value obtained by subtracting the thickness of the metal-containing polymer layer determined by EDX from the total thickness of the metal-containing polymer layer and the polymer layer determined from the secondary electron image.

[0192] (Porosity of metal layer at depths of 1 nm to 500 nm) A rectangle having the left and right sides of the rectangle described above in (Thickness of metal layer), with the lower side positioned at a depth of 1 nm from the boundary between the metal layer and the metal-containing polymer layer toward the metal layer, and the upper side positioned at a depth of 500 nm, was specified, and the area percentage (area %) of the black portion within the rectangle was obtained as a simulated value of the porosity (volume %).

[0193] (Interface roughness: ratio (L2) / (L1)) A binarized image was obtained using the same procedure as in (Metal layer thickness), except that the magnification was 100,000x and a transmission electron image was used instead of a secondary electron image. In this binarized image, the metal layer was observed as a black area except for voids, and the metal-containing polymer layer was observed as a white area. The boundary between the metal layer and the metal-containing polymer layer corresponded to the boundary between the black and white areas. The length of the boundary between the black and white areas when traced freehand over the entire binarized image was taken as the boundary line length (L2), and the length of the line segment connecting the intersections of the boundary between the black and white areas with both ends of the binarized image was taken as the in-plane length (L1) of the laminate. The ratio (L2) / (L1) was calculated.

[0194] (Metal concentration and sodium concentration in metal-containing polymer layer) The elements to be measured were copper, carbon, nitrogen, oxygen, and sodium. The measurement range was selected from a position 30 nm from the boundary between the metal layer and the metal-containing polymer layer toward the polymer layer to the boundary between the metal-containing polymer layer and the polymer layer. EDX analysis was performed in the same manner as in (thickness of metal-containing polymer layer). Note that when the thickness of the metal-containing polymer layer was 30 nm or less, the range was selected from a position 10 nm from the boundary between the metal layer and the metal-containing polymer layer toward the polymer layer to the boundary between the metal-containing polymer layer and the polymer layer. The copper concentration (as metal concentration) and sodium concentration were obtained as average values ​​within this range.

[0195] (Carbon concentration in metal layer) The elements to be measured were copper, carbon, nitrogen, oxygen, and sodium, and the measurement range was selected to be from 50 nm to 300 nm from the boundary between the metal layer and the metal-containing polymer layer toward the metal layer. EDX analysis was performed in the same manner as for (thickness of metal-containing polymer layer), with the exception that the average value within this range was taken as the carbon concentration.

[0196] (Metal concentration at a position 20 nm toward the metal layer from the boundary between the metal-containing polymer layer and the polymer layer) EDX analysis was performed using the same procedure as in (Thickness of the metal-containing polymer layer), except that copper was used as the element to be measured and a position 20 nm toward the metal layer from the boundary between the metal-containing polymer layer and the polymer layer was selected as the measurement range.

[0197] (Presence or absence of cuprous oxide in the metal layer) The laminate was cut into 1 cm squares to obtain a measurement sample. This measurement sample was mounted in an X-ray diffractometer so that the metal layer was irradiated with X-rays, and measurement was performed by X-ray diffraction (XRD) under the following conditions. (XRD measurement conditions) Measurement device: Rigaku Ultima-4 Measurement method: θ-2θ method X-ray output: 40 kV, 40 mA Scan speed: 10° / min Measurement range: 20 to 65° When peaks were observed in the range of 2θ = 35.5° to 37.5° and / or 2θ = 41.5° to 43.5° and / or 2θ = 60.5° to 62.5°, it was determined that cuprous oxide was present in the metal layer.

[0198] <Imidation Degree: Ratio (IR1) / (IR2)> The imidation degree was calculated by the following steps: (i) obtaining a measurement sample whose infrared absorption spectrum is to be measured; and (ii) measuring the infrared absorption spectrum of the measurement sample, and calculating the first peak intensity and the second peak intensity from the spectrum obtained by this measurement.

[0199] The above step (i) was carried out according to the following method. A sample cut from the laminate was embedded in resin and then cut obliquely using a room temperature microtome. The cut was made at an angle of approximately 1.8° with respect to the in-plane direction of the laminate (i.e., the direction perpendicular to the thickness direction). This allows for the production of a measurement sample with a cross section (i.e., measurement surface) that is approximately 30 times larger in cross section area than when the laminate is cut in the thickness direction.

[0200] The above step (ii) was carried out based on the following method. First, for the measurement sample obtained in the above step (i), the infrared spectrum was measured based on the attenuated total reflection infrared spectroscopy (ATR-IR method) for the polymer substrate. The measurement conditions were as follows:

[0201] (IR measurement conditions) Measurement device: Microscopic FT-IR (Bruker Hyperion) Measurement method: Reflection (ATR)-IR imaging measurement ATR crystal: Germanium (30°) ATR crystal contact mode: "REF" Detector: Focal Plane Array (FPA) detector (32 x 32 elements) Wavenumber resolution: 4 cm -1 Number of times accumulated: 32

[0202] While shifting the infrared ray irradiation position from the metal layer side to the polymer layer side, an image of about 300 μm square was acquired, and a spectrum was extracted at any position. -1 ~1722cm -1 A peak (first peak) due to the imide ring C═O stretching in the range of 1494 cm -1 ~1514cm -1 and a peak (second peak) due to the C=C stretching of the benzene ring in the range of 1 / 2000 s. After baseline correction, the ratio (IR1) / (IR2) of the peak intensity of the first peak (IR1) to the peak intensity of the second peak (IR2) was calculated as the imide degree. The imide degree distribution in the thickness direction of the laminate was evaluated by repeatedly extracting spectra and calculating the imide degree while shifting the infrared irradiation position. The minimum and maximum imide degrees were determined from a position 100 nm toward the metal-containing polymer layer from the interface between the metal layer and the metal-containing polymer layer (i.e., the dimension before enlargement by oblique cutting (i.e., in the actual laminate)) to the underside of the polymer layer.

[0203] <Presence or absence of metal (copper) chemically bonded to nitrogen atoms in the metal-containing polymer layer, and metal valence> A measurement sample was obtained using the same procedure as in (i) above. Next, this measurement sample was covered with copper tape to prevent static electricity. Then, with only an area of ​​approximately 2 mm square around the measurement area exposed, measurement was performed using X-ray photoelectron spectroscopy (XPS). The secondary electron image obtained by scanning with X-rays was observed and aligned, and the measurement point was set at a position 100 nm (as the dimension before enlargement by oblique cutting (i.e., in the actual laminate)) toward the metal-containing polymer layer from the interface between the metal layer and the metal-containing polymer layer. This resulted in a narrow scan spectrum.

[0204] (XPS measurement conditions) Measurement device: ULVAC-PHI VersaProbe II Excitation source: Monochromated Al Kα 15 kV × 0.17 mA Analysis size: 15 μmφ Photoelectron take-off angle: 45° Pass energy: 187.85 eV (Survey), 46.95 eV (Narrow) Charge correction: Cu 2p3 / 2 = 932.6 eV

[0205] Regarding the obtained narrow scan spectrum, if peaks are observed in the ranges of 569 eV to 571 eV and 930 eV to 935 eV, it indicates the presence of Cu1 valence; if peaks are observed in the ranges of 934 eV to 937 eV, it indicates the presence of Cu2 valence; if peaks are observed in the ranges of 563 eV to 566 eV (second peak) and 566 eV to 569 eV, it indicates the presence of Cu0 valence; and if peaks are observed in the range of 571 eV to 574 eV (first peak), it indicates that a nitrogen atom (N) and Cu1 valence are bonded.

[0206] The results of the above are shown in the table below.

[0207]

[0208] From the results of the Examples, Comparative Examples and Reference Examples, it is clear that the Examples provided laminates that had both good electrical conductivity and good adhesion.

[0209] The laminate and the like obtained by the present invention are suitably applied to wiring materials for electronic circuit boards and the like (printed circuit boards, RFID, replacement of wire harnesses in automobiles, etc.), antennas (antennas for portable information device housings) formed on the housings of portable information devices (smartphones, etc.), mesh electrodes (electrode films for capacitive touch panels), electromagnetic wave shielding materials, heat dissipation materials, and the like.

[0210] REFERENCE SIGNS LIST 1 laminate 10 metal wiring manufacturing apparatus 11 substrate 12 coating film 101 structure holding unit 102 light beam oscillator 103 inert gas generator 104 light beam scanning unit 104a X-axis galvanometer mirror 104b X-axis galvanometer motor 104c Y-axis galvanometer mirror 104d Y-axis galvanometer motor 105 speed control unit 106 computer ML metal layer ML1 first metal layer ML2 second metal layer MPL metal-containing polymer layer L laser light L1 in-plane length L2 boundary line length P1, P2 intersection point PL polymer layer V void

Claims

1. A laminate comprising a metal layer, a metal-containing polymer layer, and a polymer layer in this order, wherein the metal layer and the metal-containing polymer layer contain the same type of metal, the thickness of the metal layer is 0.1 μm or more and 1010 μm or less, and the thickness of the metal-containing polymer layer is 0.04 μm or more and 10 μm or less.

2. A laminate comprising a metal layer, a metal-containing polymer layer, and a polymer layer in this order, wherein the metal layer and the metal-containing polymer layer contain the same type of metal, the polymer constituting the metal-containing polymer layer and the polymer constituting the polymer layer are nitrogen-containing polymers, and the metal-containing polymer layer contains a metal chemically bonded to a nitrogen atom.

3. The laminate according to claim 1 or 2, wherein the metal-containing polymer layer contains 1 atomic % or more and 20 atomic % or less of metal.

4. The laminate according to claim 1 or 2, wherein the thickness of the polymer layer is from 1 μm to 1000 μm.

5. The laminate according to claim 1 or 2, wherein the metal layer comprises a first metal layer and a second metal layer disposed between the first metal layer and the metal-containing polymer layer, the first metal layer, the second metal layer, and the metal-containing polymer layer contain the same type of metal, the thickness of the first metal layer is 0.1 μm or more and 1000 μm or less, and the thickness of the second metal layer is 0.01 μm or more and 10 μm or less.

6. The laminate according to claim 5, wherein the second metal layer is a layer formed by reducing a layer containing copper oxide.

7. The laminate according to claim 1 or 2, wherein the metal layer comprises carbon.

8. The laminate according to claim 7, wherein the metal layer contains carbon in an amount of 0.1 atomic % or more and 15 atomic % or less.

9. The laminate of claim 1 or 2, wherein the metal layer and the metal-containing polymer layer comprise copper.

10. The laminate according to claim 1 or 2, wherein the metal layer is patterned on the metal-containing polymer layer.

11. The laminate of claim 1 or 2, wherein the metal-containing polymer layer comprises sodium.

12. The laminate according to claim 11, wherein the metal-containing polymer layer contains sodium in an amount of 0.1 atomic % or more and 10 atomic % or less.

13. The laminate according to claim 1, wherein the polymer constituting the metal-containing polymer layer and the polymer constituting the polymer layer are nitrogen-containing polymers, and the metal-containing polymer layer contains a metal chemically bonded to a nitrogen atom.

14. The laminate according to claim 1 or 2, wherein the metal-containing polymer layer contains a zero-valent and / or monovalent metal.

15. The laminate according to claim 14, wherein the metal-containing polymer layer contains zero-valent and / or monovalent metals and does not contain divalent metals.

16. The laminate of claim 14, wherein the metal-containing polymer layer comprises zero-valent and monovalent metals.

17. The laminate according to claim 1 or 2, wherein the metal concentration at a position 20 nm toward the metal layer from the boundary between the metal-containing polymer layer and the polymer layer is 1.0 atomic % or more and 5.0 atomic % or less.

18. The laminate according to claim 1 or 2, wherein in X-ray photoelectron spectroscopy measurement of the metal-containing polymer layer, a peak is present in the range of 571 eV to 574 eV.

19. A laminate according to claim 1 or 2, wherein the metal layer has a porosity of 0.1 volume % or more and 30 volume % or less in a region having a depth of 1 nm or more and 500 nm or less from the metal-containing polymer layer side.

20. The laminate of claim 1 or 2, wherein the metal layer comprises cuprous oxide.

21. A laminate according to claim 1 or 2, wherein, upon observation of a cross section in the thickness direction, the ratio (L2) / (L1) of the length (L2) of the boundary line between the metal layer and the metal-containing polymer layer to the in-plane length (L1) of the laminate is 1.0 or more and 2.2 or less.

22. The laminate of claim 1 or 2, wherein the metal-containing polymer layer is a metal-containing polyimide layer and the polymer layer is a polyimide layer.

23. The laminate according to claim 1 or 2, wherein, in infrared absorption spectrum measurement, the minimum value of the ratio (IR1) / (IR2) of the peak intensity (IR1) of a first peak derived from a first structure in the main chain to the peak intensity (IR2) of a second peak derived from a second structure in the main chain of the metal-containing polymer layer and the polymer constituting the polymer layer is 0.2 or more and 1.5 or less.

24. The laminate according to claim 1 or 2, which is used as a component of an electronic circuit board.

25. A method for producing the laminate according to claim 1 or 2, comprising: a coating step of coating a metal oxide onto a polymer substrate; and a reduction step of reducing the metal oxide.

26. The method of claim 25, wherein the reduction is carried out by irradiation with laser light.

27. The method of claim 25, further comprising an electroless metal plating step.

28. The method of claim 27, wherein the electroless metal plating step occurs after the reducing step.

29. A method for producing a laminate, comprising the steps of: forming a first metal layer having a thickness of 0.1 μm or more and 1000 μm or less; forming a second metal layer having a thickness of 0.01 μm or more and 10 μm or less; forming a metal-containing polymer layer having a thickness of 0.04 μm or more and 10 μm or less; and forming a polymer layer having a thickness of 1.0 μm or more and 1000 μm or less, wherein the first metal layer, the second metal layer, the metal-containing polymer layer, and the polymer layer are arranged in this order, and the first metal layer, the second metal layer, and the metal-containing polymer layer contain the same type of metal.

30. A method for producing a laminate as described in claim 29, wherein the step of forming the second metal layer comprises: a coating step of coating a substrate with a dispersion containing metal particles and / or metal oxide particles to form a dispersion layer; a drying step of drying the dispersion layer to form a dry coating film on the substrate; and a step of heating the dry coating film to form the second metal layer.

31. A method for producing a laminate as described in claim 29, wherein the step of forming the second metal layer comprises: a coating step of coating a substrate with a dispersion containing metal particles and / or metal oxide particles to form a dispersion layer; a drying step of drying the dispersion layer to form a dry coating film on the substrate; and a step of irradiating a laser to bake the dry coating film to form the second metal layer.

32. The method for producing a laminate according to claim 30 or 31, wherein the metal particles and / or metal oxide particles are copper particles and / or copper oxide particles.

33. The method for producing a laminate according to claim 29, wherein the step of forming the first metal layer comprises the step of forming the first metal layer by immersing the second metal layer in a plating solution.

34. The method for producing a laminate according to claim 33, wherein the plating solution has a pH of 10 or more and 14 or less.

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