Method for manufacturing laminate

Abstract

To provide a method for manufacturing a laminate in which ejection performance of a dispersion is secured in an inkjet system, a coating layer of the dispersion can be suitably formed on a substrate, and a metal layer having excellent various properties can be formed on the substrate, and a dispersion.SOLUTION: A method for manufacturing a laminate has: a coating step of forming a coating layer on a substrate by applying a dispersion containing copper particles and / or copper oxide particles onto the substrate by an inkjet system; and a firing step of forming a metal layer by firing the coating layer, where the boiling point of a dispersion medium in the dispersion is 120°C or more and 250°C or less, the inkjet system is a system of ejecting the dispersion by driving a piezo actuator corresponding to an applied voltage, an applied voltage (V1) in ejecting the dispersion in the inkjet system is 15 V or more and 40 V or less, and the slew rate (V1 / T2) in ejecting the dispersion is 5 V / μs or more and 45 V / μs or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a laminate. [Background technology]

[0002] As a constituent material of a circuit board in various electronic devices, for example, a laminate including a substrate and a metal layer on the substrate is used. This type of laminate can be produced, for example, by the following steps: a step of applying a dispersion containing metal particles and / or metal oxide particles onto a substrate by an inkjet method to form a coating layer on the substrate; a step of firing the coating layer to form a metal layer; The method can be produced by the method comprising the steps of:

[0003] In Patent Document 1, a predetermined metal film is formed by discharging a dispersion containing metal particles onto a substrate by an inkjet method. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-128228 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the method described in Patent Document 1, particles contained in the dispersion may aggregate or precipitate in the inkjet nozzle, which may result in a decrease in the ejectability of the dispersion. If the ejectability decreases, it becomes difficult to suitably form a coating layer (coating film) of the dispersion on a substrate, which in turn makes it difficult to realize a metal layer with excellent properties (for example, adhesion to the substrate).

[0006] Therefore, the present disclosure aims to provide a method for manufacturing a laminate that ensures the ejection properties of a dispersion in an inkjet system, thereby enabling a coating layer (coating film) of the dispersion to be suitably formed on a substrate, and ultimately enabling a metal layer with excellent properties (e.g., adhesion to the substrate) to be formed on the substrate. Another object of the present disclosure is to provide a dispersion that can be applied to such a production method.

[0007] One aspect of the present disclosure is as follows. [1] a coating step of coating a substrate with a dispersion containing copper particles and / or copper oxide particles by an inkjet method to form a coating layer on the substrate; and a firing step of firing the coating layer to form a metal layer, the boiling point of the dispersion medium in the dispersion is 120°C or higher and 250°C or lower, the inkjet method is a method in which the dispersion is ejected by driving a piezoelectric actuator in response to an applied voltage, In the inkjet method, The voltage applied when discharging the dispersion is 15 V or more and 40 V or less, and The through rate during ejection of the dispersion is 5 V / μs or more and 45 V / μs or less. A method for manufacturing a laminate. [2] Regarding the copper particles and / or copper oxide particles contained in the dispersion, The average particle size is 1 nm or more and 100 nm or less, and Item 2. The method for producing a laminate according to item 1, wherein the surface free energy is 20 mN / m or more and 40 mN / m or more. [3] The dispersion The absorbance at 680 nm is 14.0 or more and 115.0 or less. Item 3. A method for producing a laminate according to item 1 or 2. [4] a filtering step of filtering the dispersion to be used in the inkjet method through a filter having a pore size of 0.1 μm or more and 0.4 μm or less; A method for producing a laminate according to any one of items 1 to 3. [5] When the metal layer is referred to as a second metal layer, After the firing step, v an electroless metal plating step of electrolessly plating the second metal layer to form a first metal layer on the second metal layer; A method for producing a laminate according to any one of items 1 to 4. [6] In the electroless metal plating step, a plating solution containing formaldehyde and sodium hydroxide is used, In the plating solution, The concentration of the formaldehyde is 1.0 g / L or more and 4.0 g / L or less, The concentration of the sodium hydroxide is 1.0 g / L or more and 7.5 g / L or less, and The pH of the plating solution is 10 or more and 13.5 or less. Item 6. A method for producing a laminate according to item 5. [7] The electroless metal plating step a step of reducing bubbles contained in the layer formed by the electroless metal plating, Item 7. A method for producing a laminate according to item 5 or 6. [8] The firing step a laser light irradiation step of irradiating a laser to bake the coating layer; A method for producing a laminate according to any one of items 1 to 7. [9] A laminate obtained by the method for producing a laminate according to any one of items 1 to 8 is used as a constituent material of a flexible printed circuit board. A method for manufacturing a flexible printed circuit board.

[10] a coating step of coating a substrate with a dispersion containing copper particles and / or copper oxide particles by an inkjet method to form a coating layer on the substrate; and a firing step of firing the coating layer to form a metal layer, the boiling point of the dispersion medium in the dispersion is 120°C or higher and 250°C or lower, the inkjet method is a method in which the dispersion is ejected by driving a piezoelectric actuator in response to an applied voltage, In the inkjet method, The voltage applied when discharging the dispersion is 15 V or more and 40 V or less, and The through rate during ejection of the dispersion is 5 V / μs or more and 45 V / μs or less. A dispersion applicable to a method for producing a laminate.

[11] A dispersion comprising copper particles and / or copper oxide particles, the boiling point of the dispersion medium in the dispersion is 120°C or higher and 250°C or lower, The average particle size is 1 nm or more and 100 nm or less, The surface free energy is 20 mN / m or more and 40 mN / m or more, The absorbance at 680 nm is 14.0 or more and 115.0 or less. Dispersion. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a method for manufacturing a laminate that ensures the ejection properties of a dispersion in an inkjet system, thereby enabling a coating layer (coating film) of the dispersion to be suitably formed on a substrate, and ultimately enabling a metal layer with excellent properties (e.g., adhesion to the substrate) to be formed on the substrate. Furthermore, the present disclosure can provide a dispersion that can be applied to such a production method. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 10 is a diagram showing an example of a driving waveform for inkjet printing in the method of the present disclosure. [Figure 2] FIG. 10 is a diagram showing an example of a driving waveform for inkjet printing in the method of the present disclosure. [Figure 3] FIG. 10 is a diagram showing an example of a driving waveform for inkjet printing in the method of the present disclosure. [Figure 4] 1 is a schematic diagram of a metal wiring manufacturing apparatus that can be used in the method of the present disclosure. [Figure 5] FIG. 10 is a diagram for explaining the "number of nozzles that ejected normally." DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment 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 gist 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 manufacturing method>> <Summary> The method for producing a laminate according to the present disclosure (hereinafter sometimes referred to as the "method of the present disclosure") includes: a coating step of coating a substrate with a dispersion containing copper particles and / or copper oxide particles by an inkjet method to form a coating layer on the substrate; a firing step of firing the coating layer to form a metal layer; It has.

[0013] The laminate produced by the method of the present disclosure comprises a metal layer and a substrate, in this order. The metal layer may have a layered structure, and in particular may constitute at least one layer of the metal layer. In a typical embodiment, 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, and 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. In this case, the second metal layer may be treated as the metal layer. That is, one aspect of the method of the present disclosure is The method for producing a laminate includes a first metal layer, a second metal layer, a metal-containing polymer layer, and a polymer layer 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.

[0014] In a typical embodiment, the metal-containing polymer layer and the polymer layer are in contact with each other. In this specification, a substrate having a polymer layer and a metal-containing polymer layer may be referred to as a "polymer substrate."

[0015] The laminate produced by the method of the present disclosure can be suitably applied to, for example, circuit boards such as printed wiring boards (flexible printed circuit boards in one embodiment), and can also be suitably applied as a constituent material for circuit boards. 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 embodiment, a metal layer pattern is disposed on the 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 disposed on the substrate, and the shape and size thereof may be selected as desired. Furthermore, the laminate produced by the method of the present disclosure can be applied to antennas, reflectors, and the like. The laminate produced by the method of the present disclosure can be suitably applied as a constituent material for antennas and reflectors. This type of circuit board generally has a structure in which conductive wiring is patterned on a substrate.

[0016] In the method of the present disclosure, the coating layer (coating film) formed in the coating step may be optionally dried and then baked by laser light irradiation and / or heating.

[0017] In the method of the present disclosure, a first metal layer may be formed on a second metal layer. In one embodiment, the first metal layer may be formed by immersing a composite formed by forming a second metal layer on a polymer substrate in a plating solution, for example, an electroless metal plating solution. In addition, when forming the first metal layer, it is preferable to form the first metal layer by immersing the second metal layer in a plating solution, and in this case, it is preferable to use the plating solution having a pH of 10 or more and 13.5 or less.

[0018] In the present disclosure, one preferred embodiment of the dispersion is a coating step of coating a substrate with a dispersion containing copper particles and / or copper oxide particles by an inkjet method to form a coating layer on the substrate; The dispersion is used in a method for producing a laminate, which includes a firing step of firing the coating layer to form a metal layer. Such a dispersion may be the boiling point of the dispersion medium in the dispersion is 120°C or higher and 250°C or lower, the inkjet method is a method in which the dispersion is ejected by driving a piezoelectric actuator in response to an applied voltage; In the inkjet method, The voltage applied when discharging the dispersion is 15 V or more and 40 V or less, and The through rate during ejection of the dispersion is 5 V / μs or more and 45 V / μs or less. The present invention is applicable to a method for manufacturing a laminate.

[0019] In addition, in the present disclosure, one preferred embodiment of the dispersion is A dispersion comprising copper particles and / or copper oxide particles, the boiling point of the dispersion medium in the dispersion is 120°C or higher and 250°C or lower, The average particle size is 1 nm or more and 100 nm or less, The surface free energy is 20 mN / m or more and 40 mN / m or more, The absorbance at 680 nm is 14.0 or more and 115.0 or less.

[0020] <Coating process> In the coating process, A dispersion containing copper particles and / or copper oxide particles is applied onto a substrate by an inkjet method to form a coating layer on the substrate.

[0021] (Coating thickness) 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. The thickness of the coating film can be controlled by the amount of the metal oxide-containing dispersion applied, the number of applications, etc.

[0022] (dispersion) The dispersion contains copper particles and / or copper oxide particles. The dispersion may further contain a dispersion medium, a dispersant, and / or a reducing agent. The dispersion may be prepared by adding the dispersion medium and, optionally, the dispersant to the particles, and stirring and dispersing them using a known method such as a homogenizer.

[0023] The dispersion preferably has an absorbance at 680 nm of 14.0 or more and 115.0 or less. A dispersion having such an absorbance suitably suppresses particle aggregation, and is therefore one of the preferred embodiments for use in inkjet printing. From the same viewpoint, the absorbance at 680 nm of the dispersion is more preferably 100.0 or less, 80.0 or less, 50.0 or less, 30.0 or less, 18.0 or less, or 17.0 or less.

[0024] particle The metal particles contained in the dispersion are copper particles and / or copper oxide particles. Examples of copper oxide include cuprous oxide (CuO) and cupric oxide (CuO). Cuprous oxide is preferred because it has a high affinity with polymer substrates (particularly polyimide substrates), which facilitates 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.

[0025] Of the metal particles contained in the dispersion, copper particles and / or copper oxide particles may account for 50% by mass or more, 75% by mass or more, 90% by mass or more, or 100% by mass. The dispersion may contain metal particles other than copper particles and / or copper oxide particles (hereinafter referred to as "other metal particles"). The metal species in the other metal particles may be one or more metals selected from the group consisting of silver (Ag), nickel (Ni), chromium (Cr), tin (Sn), and zinc (Zn), and alloys containing these, which may exist as metal oxides. In the metal particles contained in the dispersion, the metal may form a complex.

[0026] The particles contained in the dispersion may have a core / shell structure, for example, the core and / or the shell may be metallic, or the core and shell may comprise different metals.

[0027] 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, 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 necessarily the primary particle diameter, but may also be the secondary particle diameter. An average particle diameter of 100 nm or less is preferred 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 preferred in that it provides good dispersion stability of the particles in the dispersion, good long-term storage stability of the dispersion, and the ability to produce uniform thin films. In one embodiment, the particles in the dispersion are essentially metal particles only. In this case, the average particle diameter value measured for the dispersion can be considered the average particle diameter of the metal particles. Furthermore, when the average particle size of the particles is 1 nm or more and 100 nm or less, it is easy to ensure the ejection properties of the dispersion in an inkjet system.

[0028] The surface free energy of the dispersion is preferably 20 mN / m or more and 40 mN / m or less. When the surface free energy of the dispersion is 20 mN / m or more, it is easy to prevent the dispersion from spreading through the nozzle opening. In this case, it is easy to suppress aggregation, precipitation, etc. of the metal particles contained in the dispersion near the inkjet nozzle opening, and as a result, it is easy to ensure the dischargeability of the dispersion. When the surface free energy is in a low range of 40 mN / m or less, the dispersion is easily discharged through the nozzle opening, and it is easy to ensure the dischargeability. Furthermore, since the affinity between the substrate and the dispersion is high, it is easy to ensure the adhesion between the substrate and the coating layer. From the same viewpoint, it is more preferable that the surface free energy of the particles is 22 mN / m or more and 35 mN / m or less or 30 mN / m or less.

[0029] 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.

[0030] 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 based on the coating method, taking into consideration volatility, the equipment used for coating, and the solvent resistance of the substrate (i.e., the substrate to be coated). 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.

[0031] The boiling point of the dispersion medium is 120°C or higher and 250°C or lower. A dispersion medium with such a relatively high boiling point can easily suppress evaporation of the dispersion medium near the inkjet nozzle. In this case, aggregation and precipitation of particles can easily be suppressed, and therefore, the ejection properties of the dispersion can be easily ensured in the inkjet method. The boiling point of the dispersion medium can be measured by known methods. Catalog values may be used as a reference for the boiling point of the dispersion medium.

[0032] 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.

[0033] Dispersants The dispersant can be a compound capable of dispersing particles in a dispersion medium. 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 ease of handling. The dispersant preferably has a group that has affinity for the metal in the particles, particularly metal oxides. Examples of such groups include a phosphate group, a hydroxyl group, an amino group, and a carboxyl 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, 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.

[0034] 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.

[0035] The acid value (mgKOH / 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 particles and / or copper oxide 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.

[0036] Furthermore, the difference between the amine value (mgKOH / 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 according to methods in accordance with 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.

[0037] The mass ratio of the dispersant to the total mass of the metals in the dispersion (dispersant mass / total mass of metals) 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 metals" refers to the total mass of the metals in the form (e.g., elemental metal, alloy, or metal compound) present in the dispersion. 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, by reducing the dispersant content in the dispersion to 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 embodiment, 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.

[0038] reducing agent When the dispersion contains metal oxide particles, it 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. Hydrazine may be in the form of hydrazine hydrate (i.e., the term "hydrazine" in the present disclosure encompasses hydrazine hydrate). Dispersions containing a reducing agent can more effectively reduce metal oxides and form metal layers with lower resistance. Hydrazine is also advantageous in maintaining the dispersion stability of the dispersion. Hydrazine in the dispersion may be present as a component of the particles and / or separately from the particles.

[0039] The content of the reducing agent in the dispersion (excluding water of hydration in the case of a hydrate) is preferably proportional to the amount of metal oxide and adjusted 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. A mass ratio of the reducing agent of 0.0001 or more is preferable in terms of good dispersion stability of the dispersion and low resistance of the metal layer, and a mass ratio of 0.1 or less results in good long-term stability of the dispersion.

[0040] 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 proportional to the amount of metal oxide and adjusted 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.

[0041] Dispersions can be produced by mixing the ingredients and dispersing them using a mixer, ultrasonicator, three-roll mill, two-roll mill, attritor, homogenizer, Banbury mixer, paint shaker, kneader, ball mill, sand mill, or planetary mixer. The viscosity of the dispersion can be designed depending on the intended application method. For example, the viscosity of a dispersion for inkjet printing is preferably 1 mPa·s or more, more preferably 3 mPa·s or more, and even more preferably 5 mPa·s or more, and preferably 20 mPa·s or less, more preferably 15 mPa·s or less, and even more preferably 12 mPa·s or less. The viscosity of the dispersion is measured at 23°C using a cone-plate rotational viscometer.

[0042] 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 the storage stability of the dispersion.

[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 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 the 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 as those in the metal layer. The metal may exist as a metal compound.

[0045] The thickness of the polymer layer is 1.0 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. 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.

[0046] 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 provide excellent adhesion due to a good anchoring effect. 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 provide excellent mechanical strength for the metal-containing polymer layer. Having a thickness below 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, electronic device, etc. However, the metal-containing polymer layer can be omitted, in which case the thickness of the metal-containing polymer layer is 0 μm.

[0047] In one embodiment, the boundary between the metal-containing polymer layer and the polymer layer is clearly distinguishable, and in one embodiment, the boundary may be confirmed as a difference in electron density in a cross-sectional image in the thickness direction by a scanning transmission electron microscope (STEM).

[0048] 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 suitable resins 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 novolac, 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).

[0049] Suitable examples of polymers include nitrogen-containing polymers and sulfur-containing polymers. 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). Sulfur-containing polymers include polyphenylene sulfide (PPS), polysulfone (PSF), and polyphenylsulfone resin (PPSU).

[0050] 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, based on 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.

[0051] 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 a 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 is, for example, a polyimide represented by the following general formula (1): [ka] (In the formula, n is a positive integer, X is a tetravalent group, and Y is a divalent group.) It has a structure represented by the following formula: n is an integer of 1 to 200, for example.

[0052] 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 radically 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.

[0053] The metal-containing polyimide layer and 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 Corporation). A metal-containing polyimide layer may be formed by infiltrating a metal into a partial region of such a polyimide film. Kapton H is preferably used as the commercially available polyimide film, as it facilitates the formation of a metal-containing polyimide layer due to the moderate progress of hydrolysis or thermal decomposition during plating or reduction, and therefore facilitates excellent adhesion.

[0054] Zero-valent and / or monovalent metals, metals chemically bonded to nitrogen atoms The metal-containing polymer layer preferably contains zero-valent and / or monovalent metals (in one embodiment, as the "same type" metal of the present disclosure), and more preferably zero-valent and monovalent metals. Monovalent metals facilitate the realization of an embodiment in which the metal is chemically bonded to a nitrogen atom.

[0055] 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. The nitrogen atom may be derived from a nitrogen-containing polymer, for example, a polyimide (particularly, an imide bond in a polyimide). An example of a metal that can chemically bond to a nitrogen atom is copper (Cu). The metal chemically bonded to the nitrogen atom contributes to improving adhesion between the metal layer and the metal-containing polymer layer due to an anchor effect. In one embodiment, 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.

[0056] Metal content 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, the amount of metal contained in the metal-containing polymer layer is preferably 10 atomic % or less, or 8 atomic % or less, or 5 atomic % or less, from the viewpoint of being able to suitably suppress excessive diffusion of the metal into the polymer and thus easily maintaining high strength of the metal-containing polymer layer. In one embodiment, the amount of the metal species present in the greatest amount based on the number of atoms among the metal species contained in the metal-containing polymer layer may be within the above range. The amount of metal in the metal-containing polymer layer tends to be greater when the manufacturing conditions of the laminate are more severe (for example, irradiation with a laser beam with higher energy, heating at a higher temperature, immersion in a more alkaline plating solution, etc.).

[0057] Sodium content of metal-containing polymer layer The metal-containing polymer layer preferably contains sodium in addition to the metals. In a typical embodiment, the sodium is derived from the plating solution. In order to control the amount of sodium 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.

[0058] 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 tends to result in 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 favorably suppresses excessive diffusion of sodium into the polymer, making it easier to maintain high strength of the metal-containing polymer layer.

[0059] (inkjet printing) Drive waveform In the method of the present disclosure, the dispersion is applied to a substrate by an inkjet method. Here, in the inkjet method, the dispersion is ejected by driving (displacing) a piezoelectric actuator in response to an applied voltage. In this method, the piezoelectric actuator functions as a pressure generating means for generating a pressure change in the ink in a pressure chamber of the inkjet head. The piezoelectric actuator has a piezoelectric layer and electrodes disposed on both sides of the piezoelectric layer, and the piezoelectric layer is displaced in response to a voltage applied to the electrodes. The voltage applied to the electrodes is realized by execution of a control program by a known microcomputer.

[0060] The control program for executing the method of the present disclosure is executed, for example, by a printer controller. The printer controller is an element that controls the entire inkjet device and, in one embodiment, is provided within the inkjet device. Here, the printer controller generates a drive waveform for the inkjet, and a voltage is applied to the piezo actuator based on the drive waveform.

[0061] Figure 1 shows an example of a drive waveform for a piezoelectric actuator, with potential on the y-axis and time on the x-axis. In the figure, the "applied voltage" to the piezoelectric actuator is understood as the potential difference between potential V0 and potential V1.

[0062] First, after waiting for a voltage holding time T1 at a predetermined potential V0, a potential V1 greater than the potential V0 is supplied to the piezo actuator over a predetermined voltage change time T2. After holding the potential V1 for a predetermined voltage holding time T3, the potential is changed to the predetermined potential V0 over a predetermined voltage change time T4. Then, the piezo actuator waits for a predetermined voltage holding time T5 at the predetermined potential V0.

[0063] In Figure 1, the piezo actuator is displaced in response to the applied voltage during voltage change time T2, which applies pressure to the ink in the pressure chamber, resulting in the ejection of the dispersion from the inkjet nozzle. In Figure 1, the "slew rate" is calculated as the "voltage that changes per unit time (V / μs)" when the dispersion is ejected, i.e., when the dispersion is pushed out from the nozzle. Specifically, in Figure 1, the "slew rate" is calculated by dividing the potential V1 by the voltage change time T2.

[0064] Supplementary information about drive waveforms 2 shows another example of a drive waveform for a piezoelectric actuator, with potential on the y-axis and time on the x-axis. In the figure, the "applied voltage" to the piezoelectric actuator is understood as the potential difference between potential V0 and potential V1.

[0065] First, a potential V1 greater than a predetermined potential V0 is applied to the piezo actuator from a predetermined potential V0 over a predetermined voltage change time T1. After holding the potential V1 for a predetermined voltage holding time T2, the potential is changed to the predetermined potential V0 over a predetermined voltage change time T3. Then, the potential V0 is kept at the predetermined potential V0 for a predetermined voltage holding time T4.

[0066] In Figure 2, the piezoelectric actuator is displaced in response to the applied voltage during the voltage change time T1, which applies pressure to the ink in the pressure chamber, causing the dispersion to be ejected from the inkjet nozzle. In Figure 2, the value obtained by dividing the potential V1 by the voltage change time T1 is calculated as the "slew rate."

[0067] Further information about drive waveforms 3 shows another example of a drive waveform for a piezoelectric actuator, with potential on the y-axis and time on the x-axis. In the figure, the "applied voltage" to the piezoelectric actuator is understood as the potential difference between potential V0 and potential V2.

[0068] First, the device waits at a predetermined potential V1 for a voltage holding time T1, and then changes to a potential V0, which is lower than the potential V1, over a predetermined voltage change time T2. Here, the potential V0 is lower than the bias voltage Vbs (potential V1 > bias voltage Vbs > potential V0). After holding the potential V0 for a predetermined voltage holding time T3, a predetermined potential V2, which is higher than the potential V1, is supplied over a predetermined voltage change time T4. The potential V2 is held at the potential V2 for a predetermined voltage holding time T5, and then changed to the predetermined potential V1 over a predetermined voltage change time T6. Then, the device waits at the predetermined potential V1 for a predetermined voltage holding time T7.

[0069] In Figure 3, negative pressure is generated in the pressure chamber during voltage change time T2, and the dispersion drawn into the pressure chamber is then ejected from the inkjet nozzle by the voltage applied to the piezo actuator during voltage change time T4. In Figure 3, the value obtained by dividing the potential V2 by the voltage change time T4 is calculated as the "slew rate."

[0070] Applied voltage when discharging dispersion In the method of the present disclosure, the voltage applied when ejecting the dispersion is 15 V or more and 40 V or less. If the applied voltage is 15 V or more, a sufficient displacement of the piezoelectric actuator can be ensured, and if the applied voltage is 40 V or less, the cycle of the drive waveform can be easily reduced, in which case continuous ejection of ink can be easily performed at high speed. Therefore, by applying a voltage of 15 V or more and 40 V or less when ejecting the dispersion, the ejection properties of the dispersion can be ensured in the inkjet method. From the same viewpoint as above, the applied voltage when ejecting the dispersion is preferably 20 V or more, more preferably 25 V or more.

[0071] Dispersion discharge slew rate In the method of the present disclosure, the slew rate during ejection of the dispersion is 5 V / μs or more and 45 V / μs or less. A slew rate of 5 V / μs or more ensures a sufficient displacement speed of the piezoelectric actuator, while a slew rate of 45 V / μs or less makes it easier for the dispersion to sufficiently follow the drive of the piezoelectric actuator. Therefore, by ensuring that the slew rate during ejection of the dispersion is 5 V / μs or more and 45 V / μs or less, the ejection properties of the dispersion can be ensured in the inkjet method.

[0072] Dischargeability Here, in the inkjet method, after discharging the dispersion, Dripping of dispersion from the nozzle, solidification of the dispersion at the nozzle opening, and particle deposition at the nozzle opening, If the above occurs, there is a possibility that droplets will not be ejected properly from the nozzles. In contrast, the method of the present disclosure can ensure the ejectability of the dispersion in the inkjet system. The inkjet ejectability is evaluated by the method described in the examples.

[0073] <Filtration process> The method of the present disclosure may include a filtration step. In the filtration step, the dispersion to be used in the inkjet method is filtered through a filter having a pore size of 0.1 μm or more and 0.4 μm or less. The filtration step is preferably carried out before the coating step. By including the filtration step in the method of the present disclosure, the dispersion in which the amount of aggregated particles has been reduced in advance can be ejected from the inkjet nozzle. This makes it easier to ensure the ejection properties of the dispersion in the inkjet method. The material of the filter may be, for example, polytetrafluoroethylene (PTFE), but is not limited to this.

[0074] <Drying process> The method of the present disclosure may include a drying step. In the drying step, the coating film obtained in the coating step is dried. Drying conditions are, for example, 60 to 120°C for 5 minutes to 5 hours. In the drying step, the coating film may be dried under reduced pressure below atmospheric pressure. For the preferred thickness of the coating film after drying, see the details described above in the section (Coating Film Thickness).

[0075] <Firing process> In the method of the present disclosure, the metal layer (in one embodiment, the second metal layer) is formed by firing the coating layer. The baking step may be carried out simultaneously with the drying step and / or the plating step, or may be carried out separately from these steps. The baking may be carried out using a known laser beam irradiation device. The firing may be performed by heating in a nitrogen atmosphere. In this case, the firing temperature is, for example, 100° C. or higher and 500° C. or lower, and the firing time is, for example, 10 minutes or higher and 5 hours or lower.

[0076] Second Metal Layer The second metal layer is formed by the inkjet method. Here, the metal layer is suitable as metal wiring in a substrate with metal wiring, such as a circuit board, etc. The shape of the metal wiring in a plan view, i.e., the pattern, may have any shape, such as a straight line, a curved line, a circle, a square, or a bent line.

[0077] The metal constituting the second metal layer is copper, particularly copper that 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) contains or consists of a reduced copper layer, the adhesion between the metal layer and the metal-containing polymer layer is likely to be excellent.

[0078] In a preferred embodiment, the metal layer (particularly the second metal layer) contains cuprous oxide, which can improve adhesion between the metal layer and the metal-containing polymer layer due to its high affinity with the polymer.

[0079] The thickness of the second metal layer is 0.01 μm or more, preferably 0.05 μm or more or 0.1 μm or more. The thickness of the second metal layer is 10 μm or less, preferably 8 μm or less or 5 μm or less, 3 μm or less or 1 μm or less. This tends to provide excellent bending resistance to the metal layer.

[0080] 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. Furthermore, the oxidation stability of the metal layer is 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.

[0081] The porosity of the second metal layer can be controlled, for example, by adjusting the output power, speed, and / or wavelength of the irradiated 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.

[0082] carbon The second metal layer 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 preferred 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, carbonized organic compounds, or the like.

[0083] The amount of carbon contained in the second metal layer 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. When the amount of carbon contained in the metal layer is within the above range, it is easier to improve the bending resistance of the metal layer, particularly the metal wiring. Here, "atomic %" means "atomic percentage," that is, the ratio of the number of atoms of a specific element (for example, carbon in the above example) to the total number of atoms of the object.

[0084] The "amount of carbon contained in the second metal layer" is measured within a range of 50 nm to 300 nm from the interface between the second metal layer and the metal-containing polymer layer in the thickness direction of the metal layer. When the thickness of the second metal layer is less than 300 nm, the amount of carbon contained in the second metal layer is interpreted as the amount of carbon contained in the entire second metal layer. For example, when 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."

[0085] Reduction process One aspect of the firing step is a reduction step. For example, in the reduction step, the oxide-containing film obtained in the coating step is reduced. 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.

[0086] 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 plating process performed after laser light irradiation easily promotes the 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.

[0087] Laser firing The firing process is It is preferable to have a laser light irradiation step in which the coating layer is irradiated with a laser and baked. For the laser beam curing method, 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 as a result, facilitating curing. The laser beam method is advantageous in that it reduces the curing time, thereby causing less damage to the substrate and is therefore suitable for application to polymer substrates with low heat resistance. The laser beam method also has the advantage of allowing for a large degree of freedom in wavelength selection, making it 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 allows exposure by beam scanning, making it easy to adjust the exposure range, and for example, it is possible to selectively irradiate (draw) only the desired area of the dried coating film without using a mask.

[0088] Types of laser light sources include YAG (yttrium aluminum garnet), YVO (yttrium vanadate), Yb (ytterbium), semiconductor lasers (GaAs, GaAlAs, GaInAs), and carbon dioxide gas. Lasers can be used not only with fundamental waves but also with harmonics extracted as necessary.

[0089] 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, resulting in the formation of low-resistance metal wiring. When cuprous oxide is used, the central wavelength is more preferably 350 nm or more and 400 nm or less.

[0090] 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.

[0091] The irradiation output of the laser light is preferably 1 mW or more, 10 mW or more, or 20 mW or more from the viewpoint of efficiently carrying out the desired firing (e.g., reduction of cuprous oxide), and is preferably 300 mW or less, 200 mW or less, 100 mW or less, or 50 mW or less from the viewpoint of easily suppressing destruction of the metal wiring due to ablation caused by excessive laser light output, and thus easily obtaining low-resistance metal wiring.

[0092] 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.

[0093] <Degreasing process> One embodiment of the method of the present disclosure may include a step of degreasing the coating prior to the plating step. Examples of degreasing methods include UV methods and wet degreasing methods. The degreasing step tends to increase the growth rate of the subsequent plating, which tends to improve 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.

[0094] From the viewpoint of easily achieving excellent adhesion between layers 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 preferable.

[0095] The degreasing liquid may be a commercially available product, and specific examples 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.

[0096] 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 inhibitors of 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 accelerating the plating reaction.

[0097] 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.

[0098] 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.

[0099] <Plating process> The plating step may involve electroless plating, electroplating, or both. For example, a second metal layer may be obtained in a reduction step, and then a first metal layer may be obtained on the second metal layer by electroless plating and / or electroplating. 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.

[0100] By appropriately setting the conditions for the plating step, reduction step, etc., a desired metal-containing polymer layer can be easily formed. For example, when a 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, a portion of the polymer can be easily modified while maintaining 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 can easily diffuse into the modified portion of the polymer substrate, and as a result, a desired metal-containing polymer layer can be easily formed.

[0101] In one embodiment, the plating is electroless plating. In one embodiment, electroless plating of a metal-containing film obtained by reducing (e.g., wet reduction) an oxide-containing film can easily improve conductivity. Electroless plating can form a metal layer composed of a metal oxide and / or metal layer and a plating layer. Electroless plating can easily form a thick metal layer, making it 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 a reduction step, a degreasing step, or a cleaning step.

[0102] A plating solution is used for electroless plating. In one embodiment, the plating solution contains EDTA (ethylenediaminetetraacetic acid). EDTA functions as a complexing agent, forming a highly stable complex with metal ions (e.g., copper ions). This is thought to suppress side reactions in the plating bath, stabilize the bath, and promote uniform plating deposition, thereby contributing to preventing peeling of the coating film. EDTA is also stable even in high-temperature solutions, and therefore contributes to accelerating the plating rate 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 the growth of the metal plating, 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 making it easy to lower the electrical resistance.

[0103] 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.

[0104] The metal ion source may exist as ions in the liquid. Examples of copper ion sources include CuSO4, CuCl2, CuCl, CuNO3, and Cu3(PO4)2, and CuCl2 and CuSO4 are preferred from the viewpoint of forming a plating layer with excellent adhesion.

[0105] 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.

[0106] 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.

[0107] The plating solution may further contain an additional complexing agent in addition to EDTA (ethylenediaminetetraacetic acid). Examples of the additional complexing agent include Rochelle salt, 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.

[0108] From the viewpoint of good plating growth, the electroless plating solution preferably contains formaldehyde. Since 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. From the viewpoint of good plating growth, the pH of the electroless plating solution is preferably 10 or higher, and from the viewpoint of preventing excessive weakening of the polymer substrate, the pH is preferably 14 or lower, or 13.5 or lower, or 13 or lower.

[0109] 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 more and 0.5 mol / L or less, or 0.01 mol / L or more and 0.3 mol / L or less, or 0.01 mol / L or more and 0.2 mol / L or less.

[0110] In one embodiment, in the plating solution, The concentration of formaldehyde (CHO) is 1.0 g / L or more and 4.0 g / L or less, The concentration of sodium hydroxide (NaOH) is 1.0 g / L or more and 7.5 g / L or less, and The pH of the plating solution is 10 or more and 13.5 or less. By using such a plating solution, it is possible to suitably form a metal layer at the second position on the second metal layer while ensuring adhesion between the substrate and the metal layer (second metal layer).

[0111] 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 Co., Ltd., OPC Copper NCA available from Okuno Pharmaceutical Industries, Ltd., C4500 available from Rohm and Haas, PrintganthUPlus available from Atotech, and Cu-510 available from Japan MacDermid.

[0112] 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 60 minutes or shorter, or 50 minutes or shorter, or 40 minutes or shorter.

[0113] 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 bubbles from the sample surface, facilitating uniform plating growth, and to agitate the plating bath, promoting uniform plating growth. In other words, the plating process is a step of reducing bubbles contained in a layer formed by electroless metal plating; It is preferred that the compound has the following structure:

[0114] 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.

[0115] 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.

[0116] 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 2A / dm 2 or more, preferably 15A / dm 2 or less than 10A / dm 2 The following is the result.

[0117] A suitable copper pyrophosphate plating bath is, for example, a plating bath containing copper pyrophosphate and potassium pyrophosphate. The copper pyrophosphate concentration 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 potassium pyrophosphate concentration 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 1A / dm 2 or more, preferably 10 A / dm 2 or less, or 7A / dm 2 The following is the result. The plating bath for electrolytic plating may further contain a surfactant.

[0118] 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.

[0119] First Metal Layer The metal layer may include a second metal layer and a first metal layer disposed on the second metal layer. The thickness of the first metal layer is 0.1 μm or more, preferably 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 1000 μm or less, preferably 500 μm or less, 100 μm or less, 50 μm or less, 10 μm or less, or 5 μm or less. This facilitates the first metal layer to have excellent bending resistance.

[0120] In one embodiment, the porosity of the first metal layer is 0.5 vol% or less, or 0.3 vol% or less. In terms of ease of forming the first metal layer, the porosity may be 0.01 vol% or more, or 0.1 vol% or more.

[0121] 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. Note that it is also possible to control (e.g., reduce) the porosity of the formed second metal layer, for example, by adjusting the plating conditions, performing a degreasing step before plating, etc.

[0122] <Metal wiring manufacturing equipment> The laminate of this embodiment can be manufactured using, for example, the following apparatus. 4 is a schematic diagram of a metal wiring manufacturing apparatus used in one embodiment of the present invention. The metal wiring manufacturing apparatus 10 includes a structure holding unit 101 and a light beam oscillator 102. The metal wiring manufacturing apparatus 10 may also include an inert gas generator 103, a light beam scanning unit 104, a speed control unit 105, and / or a computer 106.

[0123] <Structure holding section> In one embodiment, the structure holder 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.

[0124] <Optical 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), 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.

[0125] <Light scanning unit> The light beam scanning unit 104 scans the light beam L emitted from the light beam oscillator 102. FIG. 4 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 has 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 also have an fθ lens (not shown), a Z-axis adjustment drive lens (not shown), etc. 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).

[0126] 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 . 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 .

[0127] Although a galvanometer scanner has been exemplified above as the light beam scanning unit 104, 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 XY 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.

[0128] The light beam scanning unit 104 (galvanometer scanner) shown in FIG. 4 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.

[0129] 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 length (L) (unit: mm) of the scanning line 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 equation: Scanning speed (V) = scanning period (F) x scanning line length (L)

[0130] 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 way, 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 scanning line so that the scanning period (F) is the same at any position within the coating film 12. [Example]

[0131] 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. The steps, treatments, operations, etc. described below were carried out at room temperature (e.g., 25°C) unless otherwise specified.

[0132] <Measurement and evaluation methods> <Particle diameter (nm)> The particle size of the dispersion was measured by the cumulant method using FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.).

[0133] <Surface free energy (mN / m)> The surface free energy of the particles was measured by the pendant drop method at 23°C using an interfacial tensiometer, DropMaster 700 (Kyowa Interface Science Co., Ltd.), and calculated by the Young-Laplace law.

[0134] <Absorbance> The absorbance of the dispersion was measured at room temperature in the wavelength range of 400 to 800 nm using a UV-1800 ultraviolet-visible spectrophotometer (Shimadzu Corporation), and the absorbance at a wavelength of 680 nm was read from the obtained spectrum.

[0135] <Dischargeability (discharge rate;%)> The ejection properties in inkjet printing were measured as follows. First, a printer device having multiple inkjet nozzles was prepared. Then, a cartridge of the printer device was filled with a dispersion filtered through a PTFE filter with a pore size of 0.2 μm. After filling the cartridge with the dispersion, the dispersion was ejected from the inkjet nozzles 0 minutes and 30 minutes later. The ratio of the number of nozzles that ejected droplets normally to the total number of nozzles (number of nozzles that ejected normally / total number of nozzles) was used as the ejectability (%). The ejection was visually confirmed using the observation software "DropWatcher."

[0136] Figures 5(a) and 5(b) are schematic diagrams for explaining the "number of nozzles that ejected normally." Of these, Figure 5(a) shows ejection 0 minutes after filling the dispersion, and Figure 5(b) shows ejection 30 minutes after filling the dispersion.

[0137] In the drawing, a total of 25 nozzles N1 to N25 are arranged in parallel along the X direction. Dispersion D is ejected from each nozzle in the Y direction along the axis A of each nozzle.

[0138] 5(a), dispersions D1 to D25 are ejected from all of the nozzles N1 to N25. Here, the illustration shows a scene in which dispersion D reaches a predetermined ejection distance L_0min over a time T. In one embodiment, the ejection distance L_0min is 500 μm. There is almost no deviation in the discharge speed of the dispersions D1 to D25, and therefore, no deviation in the Y direction is observed for each dispersion D after the time T has elapsed since discharge. Furthermore, there is almost no deviation in the ejection direction of the dispersions D1 to D25, and therefore, no deviation in the X direction is observed for each dispersion D after the time T has elapsed since ejection.

[0139] Here, in the inkjet method, after discharging the dispersion, Dripping of dispersion near the nozzle, solidification of the dispersion near the nozzle, and Particle deposition near the nozzle, If the above occurs, there is a possibility that droplets will not be ejected properly from the nozzles.

[0140] For example, in Figure 5(b), nozzle N2 does not eject dispersion D. Such nozzle N2, from which dispersion D is not ejected, is not included in the "nozzles that eject normally."

[0141] Furthermore, for nozzle N3, dispersion D3 is ejected, but the ejection distance L_30min after 30 minutes is shorter than the ejection distance L_0min after 0 minutes by at least the length Y_D of the dispersion. Thus, at the time T, the following equation: Displacement ΔY of dispersion D in the Y direction ≥ Length Y_D of dispersion D in the Y direction (Y-direction deviation of dispersion D ΔY = discharge distance L_0 min - discharge distance L_30 min) The nozzle N3 for which the above condition holds is also not included in the "nozzles that normally eject droplets."

[0142] Furthermore, although dispersion D4 is being discharged from nozzle N4, the axis Y_A of dispersion D4 is deviated from the axial direction A of the nozzle by at least the width X_D of the dispersion. Thus, at the time T, the following equation: X-direction deviation ΔX of dispersion D ≧ X-direction length X_D of dispersion D (X-direction deviation of dispersion body D ΔX = difference X_A between nozzle axis A and axis Y_A of dispersion body D) The nozzle N4 for which the above condition holds is also not included in the "nozzles that ejected normally."

[0143] In the drawing, the "number of nozzles that ejected normally" is the total of 22 nozzles, excluding N2, N3, and N4 from the total of 25 nozzles N1 to N25. In this case, the ejectability (%) is calculated as 22 / 25 = 88 (%).

[0144] In this embodiment, If the discharge rate after 30 minutes was 86% or more, the rating was "A". If the discharge rate after 30 minutes was 60% or more but less than 86%, it was rated as "B". If the discharge rate after 30 minutes was 10% or more but less than 60%, the rating was "C". If the discharge rate after 30 minutes was less than 10%, the rating was "D". It was evaluated as follows.

[0145] Here, in the evaluation of the ejection properties, a piezo-type inkjet printer, Material Printer DMP-2835 (manufactured by FUJIFILM Dimatix), was used, and a samba cartridge was used. The device configuration is as follows. (Device configuration) Equipment: Material printer DMP-2835 (FUJIFILM Dimatix) Cartridge: Samba 2.4pl Number of nozzles: 14

[0146] In addition, in the evaluation of the ejection properties, the inkjet driving waveform was set as shown in FIG. 1, below, and in the table below. (Drive waveform setting) Voltage holding time T1: 0.51 μs Voltage change time T2: Values listed in the table below Voltage holding time T3: 1.31 μs Voltage change time T4: 0.97 μs Voltage holding time T5: 3.38 μs Applied voltage V1: Values shown in the table below

[0147] <Production of dispersion and laminate> [Example 1] Dispersions and laminates were prepared by the following methods, and various evaluations were carried out for each.

[0148] <Dispersion> a solvent consisting of 30,240 g of ion-exchanged water and 13,976 g of 1,2-propylene glycol (manufactured by Asahi Glass Co., Ltd.); 3224 g of copper(II) acetate monohydrate (manufactured by Nippon Chemical Industry Co., Ltd.), 940g of hydrazine hydrate (manufactured by Nippon Finechem Co., Ltd.) The mixture was mixed and stirred under a nitrogen atmosphere. The mixture was then centrifuged to separate the supernatant and precipitate. The precipitate was allowed to stand at room temperature under a nitrogen atmosphere for 1 to 30 minutes to adjust the water content of the precipitate, thereby adjusting the water content of the final dispersion.

[0149] 72 g of DISPERBYK-145 (trade name, manufactured by BYK-Chemie) (BYK-118) as a phosphorus-containing organic compound, 764 g of 1-heptanol (manufactured by Toyo Gosei Co., Ltd.) as a dispersion medium, A mixed solution was obtained by mixing the above. 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 N2 atmosphere. This resulted in a dispersion containing cuprous oxide particles. Such cuprous oxide particles contain cuprous oxide (copper(I) oxide).

[0150] 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 an N2 atmosphere to obtain the target dispersion.

[0151] The final composition of the dispersion contained 0.2% by mass of hydrazine. The solid residue (cuprous oxide particles) after heating the dispersion at normal pressure and 60°C for 4.5 hours was 26.1% by mass. The average particle size of the cuprous oxide particles was 28 nm. The surface free energy of the dispersion was 25.6 mN / m.

[0152] [Example 2] and [Comparative Example 1] Except for changing the items described in the table below as shown in the table below, a dispersion was obtained in the same manner as in Example 1. Furthermore, various evaluations were carried out on the obtained dispersion.

[0153] Example 1A <Dispersion> The dispersion prepared in Example 1 was used. Here, the dispersion prepared in Example 1 was filtered through a PTFE filter with a pore size of 0.2 μm before use.

[0154] <Polymer substrate> A 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.

[0155] <Inkjet printing> The dispersion was used as ink and printed on the surface of the substrate using an inkjet printer (FUJIFILM Dimatix Material Printer DMP-2835). The cartridge was DMC-11601, the voltage V1 was 40 V, the voltage change time T2 was 0.93 μs, and the slew rate was 43 V / μs (driving waveform shown in Figure 1). Here, a 50 mm x 50 mm pattern was drawn. After printing, the substrate was dried at 60°C for 30 minutes. This resulted in a sample with a coating film formed on the substrate.

[0156] <Firing> A metal wiring manufacturing apparatus 10 having the configuration shown in FIG. 4 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 1.7 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 being moved 10 μm at a time in the direction perpendicular to the scanning direction. As a result, a copper-containing metal layer measuring 20 mm in length and 10 mm in width was formed on the polyimide substrate.

[0157] <Plating> Next, an electroless plating solution containing formaldehyde and sodium hydroxide (manufactured by Okuno Chemical Industries Co., Ltd., product name: OPC Copper NCA) (containing 2.1 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 6.8 g / 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 plated metal layer (first metal layer) on the metal layer (second metal layer).

[0158] Example 2A <Dispersion> The dispersion prepared in Example 1 was used. Here, the dispersion prepared in Example 1 was filtered through a PTFE filter with a pore size of 0.2 μm before use.

[0159] <Polymer substrate and inkjet printing> The same operations as those in Example 1A (polymer substrate and inkjet printing) were carried out in this example.

[0160] <Metal (second metal layer)> The 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.

[0161] <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 2.0 g / L. During the 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).

[0162] Example 3A <Dispersion> The dispersion prepared in Example 1 was used. Here, the dispersion prepared in Example 1 was filtered through a PTFE filter with a pore size of 0.2 μm before use.

[0163] The same procedures as in Example 2A were followed for the polymer substrate and inkjet printing, and the metal (second metal layer).

[0164] <Metal layer (first metal layer)> Next, an electroless plating solution containing formaldehyde and sodium hydroxide (manufactured by Okuno Chemical Industries, Ltd., product name: OPC Copper NCA) 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 11.9. During immersion, the sample was shaken up and down (rocking 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). The concentrations (g / L) of sodium hydroxide and formaldehyde in the plating solution were adjusted as shown in the table below.

[0165] Example 4A The same procedures as in Example 3A were followed for the dispersion, polymer substrate and inkjet printing, and metal (second metal layer).

[0166] <Metal layer (first metal layer)> A plating layer (first metal layer) was formed on the copper-containing film (second metal layer) in the same manner as in Example 1A, except that the sample was not rocked while immersed in the plating solution. The swinging operation here is as follows: a step of reducing bubbles contained in a layer formed by electroless metal plating; This is one aspect of the above.

[0167] Example 5A A laminate was obtained in the same manner as in Example 2A, except that the procedure for <Metal Layer (First Metal Layer)> was not carried out (that is, the first metal layer was not formed).

[0168] <Evaluation> The laminates according to the examples and reference examples were evaluated by the following methods.

[0169] <Resistance value evaluation> The resistance 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 resistance was measured. The evaluation criteria were as follows: a volume resistance of less than 10 μΩcm was rated "A," and a volume resistance of 10 μΩcm or more was rated "B." The evaluation results are shown in the table below.

[0170] <Evaluation of Adhesion> For laminates that received an "A" rating in the "Evaluation of Resistance Value" section above, adhesion was evaluated using a tape peeling test. A tape with an adhesive 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 at a 60-degree angle between the surface and the tape. If peeling did not occur, a tape with an adhesive 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 at a 60-degree angle between the surface and the tape. The evaluation criteria were as follows: "A" indicates that the metal layer did not peel off from the laminate with the 1.5 N / mm tape; "B" indicates that the metal layer did not peel off with the 0.4 N / mm tape, but peeled off with the 1.5 N / mm tape; and "C" indicates that the metal layer peeled off with the 0.4 N / mm tape. The evaluation results are shown in the table below.

[0171] 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."

[0172] <Evaluation of adhesion reproducibility> The above-mentioned <Adhesion Evaluation> was performed at four different locations within the laminate. Specifically, for Examples 2, 3, and 4, four 20 mm × 20 mm test pieces were cut from the laminate at 5 mm intervals. For Example 1, because the size of the laminate was smaller than the above-mentioned test pieces, four 20 mm × 10 mm laminates were prepared and similar evaluations were performed on all four pieces. The evaluation criteria were as follows: "A" indicates that results similar to those in the <Adhesion Evaluation> column were obtained at all four locations; "B" indicates that results similar to those in the <Adhesion Evaluation> 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.

[0173] The results of the above are shown in the table below.

[0174] [Table 1]

[0175] <Additional information about ejection properties> In the evaluation of the ejection properties, if there is a problem in adopting the above-mentioned device configuration, the following device configuration is used. Equipment: Material printer DMP-2835 (FUJIFILM Dimatix) Cartridge: DMC-11601 Number of nozzles: 16

[0176] Here, the inkjet drive waveform is set as shown in Figure 2, below, and in the table below. (Drive waveform setting) Voltage change time T1: Values shown in the table below Voltage holding time T2: 2.4 μs Voltage change time T3: 15.9 μs Voltage holding time T4: 4.0 μs Applied voltage V1: Values shown in the table below

[0177] [Example 3] to [Example 7] A dispersion is prepared in the same manner as in Example 1, except that the items described in the table below are changed as shown in the table below. When various evaluations are performed on the prepared dispersion, the results shown in the table below are expected to be obtained.

[0178] [Table 2]

[0179] <Further information on ejection> In the evaluation of the ejection properties, if there is a problem in adopting the above-mentioned device configuration, the following device configuration is used. Equipment: R&D inkjet device IJX-H103 (Epson) Inkjet head: S800-U1 Number of nozzles: 800

[0180] Here, the inkjet drive waveform is set as shown in Figure 3, below, and in the table below. (Drive waveform setting) Voltage holding time T1: 2.0 μs Voltage change time T2: 2.0 μs Voltage holding time T3: 3.3 μs Voltage change time T4: Values listed in the table below Voltage holding time T5: 4.5 μs Voltage change time T6: 2.0 μs Voltage holding time T7: 2.0 μs Applied voltage V1: 55% of applied voltage V2 Applied voltage V2: Values shown in the table below

[0181] [Examples 8] to [Examples 10] and [Comparative Example 2] A dispersion is prepared in the same manner as in Example 1, except that the items described in the table below are changed as shown in the table below. When various evaluations are performed on the prepared dispersion, the results shown in the table below are expected to be obtained.

[0182] [Table 3]

[0183] If you want to print thin lines or thin the coating thickness, you can use the DMC-11601 cartridge for the material printer DMP-2835 (manufactured by FUJIFILM Dimatix), which has a relatively small amount of ink ejected from each nozzle. The amount of ink ejected from each nozzle is 1 pl for the DMC-11601 and 2.4 pl for the samba cartridge. When inkjet printing a large number of sheets at once or when inkjet printing over a large area, the R&D inkjet device IJX-H103 can be used, which can fill with more ink than the material printer DMP-2835. In the evaluation of ejectability, the results obtained under the conditions described in <Ejectability (ejection rate; %)> shall take precedence, and the results obtained under the conditions described in <Additional information on ejectability> and <Further additional information on ejectability> may be referred to for reference. [Industrial Applicability]

[0184] The present invention is suitably applicable to fields such as 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, and heat dissipation materials. [Explanation of symbols]

[0185] N1~N25 inkjet nozzles D1~D25 Dispersion 10 Metal wiring manufacturing equipment 11 Base material 12 Paint film 101 Structure holding part 102 Light Oscillator 103 Inert Gas Generator 104 Light 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 section 106 Computer L laser light

Claims

1. a coating step of coating a substrate with a dispersion containing copper particles and / or copper oxide particles by an inkjet method to form a coating layer on the substrate; and a firing step of firing the coating layer to form a metal layer, the boiling point of the dispersion medium in the dispersion is 120°C or higher and 250°C or lower, the inkjet method is a method in which the dispersion is ejected by driving a piezoelectric actuator in response to an applied voltage, In the inkjet method, The voltage applied when discharging the dispersion is 15 V or more and 40 V or less, and the through rate during ejection of the dispersion is 5 V / μs or more and 45 V / μs or less; A method for manufacturing a laminate.

2. Regarding the copper particles and / or copper oxide particles contained in the dispersion, The average particle size is 1 nm or more and 100 nm or less, and The method for producing a laminate according to claim 1 , wherein the surface free energy is 20 mN / m or more and 40 mN / m or more.

3. The dispersion The absorbance at 680 nm is 14.0 or more and 115.0 or less. A method for producing the laminate according to claim 1 or 2.

4. a filtration step of filtering the dispersion to be used in the inkjet method through a filter having a pore size of 0.1 μm or more and 0.4 μm or less; A method for producing the laminate according to claim 1 or 2.

5. When the metal layer is referred to as a second metal layer, After the firing step, an electroless metal plating step of electrolessly plating the second metal layer to form a first metal layer on the second metal layer; A method for producing the laminate according to claim 1 or 2.

6. In the electroless metal plating step, a plating solution containing formaldehyde and sodium hydroxide is used, In the plating solution, The concentration of the formaldehyde is 1.0 g / L or more and 4.0 g / L or less, The concentration of the sodium hydroxide is 1.0 g / L or more and 7.5 g / L or less, and The pH of the plating solution is 10 or more and 13.5 or less. A method for producing the laminate according to claim 5.

7. The electroless metal plating step a step of reducing bubbles contained in the layer formed by the electroless metal plating, A method for producing the laminate according to claim 5.

8. The firing step a laser light irradiation step of irradiating a laser to bake the coating layer; A method for producing the laminate according to claim 1 or 2.

9. The laminate obtained by the method for producing a laminate according to claim 1 or 2 is used as a constituent material of a flexible printed circuit board. A method for manufacturing a flexible printed circuit board.

10. a coating step of coating a substrate with a dispersion containing copper particles and / or copper oxide particles by an inkjet method to form a coating layer on the substrate; and a firing step of firing the coating layer to form a metal layer, the boiling point of the dispersion medium in the dispersion is 120°C or higher and 250°C or lower, the inkjet method is a method in which the dispersion is ejected by driving a piezoelectric actuator in response to an applied voltage, In the inkjet method, The voltage applied when discharging the dispersion is 15 V or more and 40 V or less, and the through rate during ejection of the dispersion is 5 V / μs or more and 45 V / μs or less; A dispersion applicable to a method for producing a laminate.

11. A dispersion comprising copper particles and / or copper oxide particles, the boiling point of the dispersion medium in the dispersion is 120°C or higher and 250°C or lower, The average particle size is 1 nm or more and 100 nm or less, The surface free energy is 20 mN / m or more and 40 mN / m or more, The absorbance at 680 nm is 14.0 or more and 115.0 or less. Dispersion.

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