JP5772539B2 - Method for producing copper oxide paste and metallic copper layer - Google Patents

Description

  The present invention relates to a copper oxide paste and a method for producing a metal copper layer.

  Conventionally, a technique using a photoresist and a photomask has been used to form a fine pattern of metallic copper, such as an electronic circuit and a terminal. On the other hand, the technique of printing and metalizing the ink that is the basis of metallic copper by printing method to form a fine pattern of metallic copper reduces costs, reduces processes, reduces input materials and waste, and applies to large area devices It has come to be considered from the point of.

  For example, a resin binder copper paste in which copper particles are mixed with a binder resin has been proposed and actually used. However, in the conductive pattern formed from such a resin binder copper paste, conductivity is obtained by contact between the copper particles in the paste, but there is a problem that resistance is increased. Furthermore, since the number of contacts between the copper particles in the conductive path can be a factor that increases the resistance, the reduction in the particle size of the copper particles is accompanied by an increase in the number of contacts in the conductive path, resulting in an increase in resistance. For this reason, it is practically difficult to reduce the copper particle size necessary for forming a fine pattern having a line width of 70 μm or less.

In relation to the above, copper inks and pastes containing copper nanoparticles and no binder have been proposed. This method is expected to achieve both fine pattern formability and low resistance because a metal bond is formed between metal particles to reduce resistance by conducting a conductor after pattern formation and drying.
On the other hand, it is disclosed that a low-resistance metallic copper film can be obtained by patterning with a deposited layer of copper oxide particles instead of metallic copper particles, and heating this in a formic acid-containing inert gas to 140 to 200 ° C. (For example, see Patent Document 1).

International Publication No. 2011/0334016 Pamphlet

  An object of the present invention is to provide a copper oxide paste capable of accurately forming a high-definition and low-resistance metal copper layer and a method for producing a metal copper layer using the same.

Specific means for solving the above problems are as follows.
<1> Parallel two planes that include a plurality of copper oxide particles and are selected so that the distance between the two parallel planes is the largest among the two parallel planes circumscribing the copper oxide particles in the three-dimensional shape of the copper oxide particles. The distance between the two parallel planes selected so that the distance between the parallel two planes is the shortest of the two parallel planes orthogonal to the parallel two planes that give the major axis and circumscribing the copper oxide particles is short. When the diameter is set, the average value of the length of the major axis is 100 nm or more and less than 1700 nm for the plurality of copper oxide particles, and the ratio of the average value of the length of the major axis to the average value of the length of the minor axis Is a copper oxide paste containing a copper oxide particle group having a particle size of 1.2 or more and 20 or less and a dispersion medium.

<2> The parallel two planes selected so that the distance between the two parallel planes is the largest among the two parallel planes that are orthogonal to the parallel two planes that give the major axis and circumscribe the copper oxide particles. When the intermediate distance is the medium diameter, the average length of the major axis is 100 nm or more and less than 1700 nm for the plurality of copper oxide particles, and the length of the major axis with respect to the average value of the minor axis length The copper oxide according to <1>, wherein the ratio of the average value is 1.2 or more and 20 or less, and the ratio of the average value of the length of the long diameter to the average value of the length of the medium diameter is 2.0 or more. It is a paste.

<3> The content ratio of all the particles including the copper oxide particle group is 30% by mass or more and 80% by mass or less, and the content ratio of the copper oxide particle group in all the particles is 50% by mass or more. Or it is a copper oxide paste as described in <2>.

<4> The equilibrium viscosity of Casson measured by a viscoelasticity measuring device equipped with a cone plate is 0.01 Pa · s or more and 200 Pa · s or less, according to any one of the above <1> to <3>. It is a copper oxide paste.

<5> The copper oxide paste according to any one of <1> to <4>, wherein the dispersion medium includes an organic solvent having a vapor pressure of less than 1.34 × 10 ³ Pa · s at 25 ° C. is there.

<6> The copper oxide paste according to any one of <1> to <5>, which is for forming a metal copper layer.

<7> A step of applying the copper oxide paste according to any one of <1> to <6> on the support to form a copper oxide particle-containing layer, and the copper oxide particle-containing layer as a conductor And a step of forming a metal copper layer by performing a chemical treatment.

<8> The method according to <7>, wherein the method of applying the copper oxide paste is a printing method.

<9> The production method according to <7> or <8>, wherein the conductorization treatment is a method of heat-treating the copper oxide particle-containing layer in a formic acid-containing atmosphere.

<10> The method according to any one of <7> to <9>, further including a step of subjecting the formed metal copper layer to an electrolytic plating treatment or an electroless plating treatment.

<11> A conductor wiring including a metallic copper layer obtained by the production method according to any one of <7> to <10>.

<12> An electrode including a metallic copper layer obtained by the production method according to any one of <7> to <10>.

<13> A heat conduction path including a metallic copper layer obtained by the production method according to any one of <7> to <10>.

  According to the present invention, it is possible to provide a copper oxide paste capable of accurately forming a high-definition and low-resistance metal copper layer and a method for producing a metal copper layer using the same.

It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle concerning manufacture example 1. FIG. It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle concerning manufacture example 2. FIG. It is a figure which shows an example of the X-ray-diffraction spectrum of the copper oxide particle concerning manufacture examples 1-3. It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle concerning manufacture example 4. FIG. It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle concerning manufacture example 7. FIG. It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle concerning manufacture example 8. FIG. It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle concerning manufacture example 9. FIG. It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle concerning manufacture example 10. FIG. It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle used for Example 13. It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle used for the comparative example 2. FIG. It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle used for the comparative example 3. It is a figure which shows an example of the scanning electron microscope image of the copper oxide particle used for the comparative example 4. It is a figure which shows an example of the copper oxide particle content layer pattern formed from the copper oxide paste concerning Example 1. FIG. It is a figure which shows an example of the copper oxide particle content layer pattern formed from the copper oxide paste concerning Example 13. FIG. It is a figure which shows an example of the copper oxide particle content layer pattern formed from the copper oxide paste concerning the comparative example 2. FIG. It is a figure which shows an example of the copper oxide particle content layer pattern formed from the copper oxide paste concerning the comparative example 3. It is a figure which shows an example of the scanning ion microscope image of the metal copper layer cross section formed from the copper oxide paste concerning Example 1. FIG. It is a perspective view which shows typically the method of measuring the shape of a copper oxide particle. It is a figure which illustrates typically the parameter which prescribes | regulates the shape of a copper oxide particle.

In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes. . In the present specification, a numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. Further, in the present specification, the content of each component in the composition is the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. Means.
<Copper oxide paste>
The copper oxide paste of the present invention has an average value of the length of the major axis of 100 nm or more and less than 1700 nm, and the ratio of the average value of the length of the major axis to the average value of the length of the minor axis is 1.2 or more and 20 or less. It includes a copper particle group and a dispersion medium, and includes other components as necessary. By including a group of copper oxide particles having a specific shape, a high-definition and low-resistance metal copper layer can be formed with excellent accuracy. This can be considered as follows, for example.

  In the formation of a copper metal layer pattern using a copper oxide paste, as the physical properties of the copper oxide paste, the pattern formation property of the copper oxide particle-containing layer and the pattern shape when conducting the heat treatment in a reducing atmosphere to form a conductor Stability is required. Here, if the physical properties of the copper oxide paste are adjusted by a dispersant or an additive (for example, a thixotropic agent or a viscosity modifier), sufficient conductivity may not be obtained in the conductor treatment. On the other hand, since the copper oxide particle group has a specific shape and high affinity with the dispersion medium, the copper oxide paste configured to include the copper oxide particle group has physical properties adjusted by a dispersant or an additive. Even if it is not, it exhibits excellent physical properties such as pattern formability and shape stability. Therefore, it is considered that a metal copper layer pattern having high conductivity can be formed during the conductor treatment.

(Copper oxide particles)
The copper oxide particle group contained in the copper oxide paste includes a plurality of specific shapes of copper oxide particles (hereinafter, also referred to as “long granular copper oxide particles”). In the three-dimensional shape of the copper oxide particles, the copper oxide particles Of the parallel two planes circumscribing the particles, the distance between the parallel two planes having the maximum distance is taken as the major axis, and among the parallel two planes that are orthogonal to the parallel two planes that give the major axis and circumscribe the copper oxide particles, The distance between the parallel two planes where the distance is the shortest, and the distance between the parallel two planes where the distance is the maximum among the parallel two planes orthogonal to the parallel two planes giving the major axis and circumscribing the copper oxide particles Is an average value of the length of the major axis (hereinafter also referred to as “average major axis”) is 100 nm or more and less than 1700 nm, and the average value of the length of the minor axis (hereinafter referred to as “average minor axis”). Mean length of major axis The ratio of (average major axis / average minor diameter) of 1.2 or more and 20 or less. The long granular copper oxide particles are excellent in dispersibility in a dispersion medium due to their characteristic shape, and therefore, the copper oxide paste containing this has excellent suitability for application to a support, and a high-definition copper oxide particle-containing layer is high. It can be formed with high accuracy. In addition, when the formed copper oxide particle-containing layer is subjected to a conductor treatment, a dense metal copper layer with low resistance can be formed.

  Further, the copper oxide particle group is selected such that the distance between the parallel two planes is selected so as to maximize the distance between the parallel two planes, which is perpendicular to the parallel two planes that give the major axis and circumscribes the copper oxide particles. Is the average diameter of the major axis of the plurality of copper oxide particles is 100 nm or more and less than 1700 nm, and the average value of the major axis length relative to the minor axis length average value The ratio of the average length of the long diameter to the average value of the length of the medium diameter (hereinafter also referred to as “average medium diameter”) is 2.0 or more. It is preferable.

  The three-dimensional shape of the copper oxide particles constituting the copper oxide particle group is an observation method for directly obtaining the three-dimensional shape information of the particles such as a three-dimensional transmission electron microscope, FIB / scanning electron microscope, and 3D X-ray tomography. Can be observed. Note that the three-dimensional shape of the copper oxide particles is observed under the condition that the observed copper oxide particles can be identified as independent particles. For example, the magnification is 20,000 times, and the concentration of the copper oxide particles is appropriately diluted.

  The shape of the copper oxide particles is defined by the average value of the lengths of the major axis, the minor axis, and, if necessary, the medium diameter. Here, the length of the major axis is given as the distance between two parallel planes selected so that the distance between the parallel two planes becomes the maximum among the parallel two planes circumscribing the copper oxide particles. Further, the length of the small diameter is a distance between the parallel two planes selected so that the distance between the parallel two planes is the smallest among the parallel two planes orthogonal to the parallel two planes giving the long diameter and circumscribing the copper oxide particles. As given. Further, the length of the medium diameter is between the parallel two planes selected so that the distance between the parallel two planes is the maximum among the parallel two planes orthogonal to the parallel two planes giving the major axis and circumscribing the copper oxide particles. Given as a distance. Moreover, the average value of each length of a long diameter, a medium diameter, and a short diameter measures a long diameter, a medium diameter, and a short diameter, respectively about 20 copper oxide particles arbitrarily selected, and is given as each arithmetic mean value. .

  The lengths of the major, middle and minor diameters of the copper oxide particles constituting the copper oxide particle group were observed by observing a planar image of the copper oxide particles using a scanning electron microscope and a transmission electron microscope. From the above, it can be measured in the same manner as described above assuming a three-dimensional shape of the copper oxide particles. For example, the length of each of the long diameter, the medium diameter, and the small diameter can be measured by using a set of two tangent lines that are circumscribed by different contact points on the outer periphery of the planar image. . In addition, it observes on the conditions which can identify each copper oxide particle observed as an independent particle | grain. For example, observation with a scanning electron microscope is performed at a magnification of 20,000 (acceleration voltage 5 kV).

  A method for measuring the lengths of the major diameter, the middle diameter, and the minor diameter of the copper oxide particles will be described with reference to the schematic diagram shown in FIG. Among the parallel planes circumscribing the copper oxide particles 1 schematically shown in FIG. 18, the first parallel plane that maximizes the distance between the parallel planes is selected, and oxidation is performed as the distance between the first parallel planes. The length 2 of the major axis of the copper particle 1 is measured. In addition, a second parallel two plane having a minimum distance between the parallel two planes is selected from the parallel two planes orthogonal to the first parallel two planes and circumscribing the copper oxide particles 1. The length 4 of the minor axis of the copper oxide particles 1 is measured as the distance between the planes. Further, a third parallel two plane having a maximum distance between the parallel two planes is selected from the two parallel planes orthogonal to the first parallel two planes and circumscribing the copper oxide particles 1, and the third parallel plane is selected. The length 3 of the medium diameter is measured as the distance between the two planes.

  The copper oxide particles constituting the copper oxide particle group have an average length of the major axis of 100 nm or more and less than 1700 nm, but from the viewpoint of dispersibility and the fineness of the conductor pattern to be formed, the copper oxide particles are 100 nm or more and 1500 nm or less. Preferably, it is 100 nm or more and 1000 nm or less, and more preferably 100 nm or more and 600 nm or less. In addition, the length of the major axis of the copper oxide particles is measured as described above, and the average major axis is calculated as the arithmetic mean of the measured values for the 20 copper oxide particles. When the copper oxide paste is prepared by using the copper oxide, the viscosity of the copper oxide paste increases as the particle size decreases, and therefore the concentration of the copper oxide particles in the copper oxide paste tends to be low when the desired viscosity is prepared. . On the other hand, when a copper oxide paste is prepared using a copper oxide particle group having an average major axis exceeding 1700 nm, the printability of the copper oxide paste tends to be reduced, and the copper oxide particle group production method described later further decreases. It becomes difficult to synthesize.

  The copper oxide particles preferably have a major axis length variation coefficient of 20% or less, and preferably 15% or less. Thus, dispersibility improves more because the dispersion | variation in particle shape is small. The coefficient of variation is obtained by dividing the standard deviation by the average value.

  Preferred shapes of the copper oxide particles constituting the copper oxide particle group are not substantially spherical and fibrous, but are plate-like, flake-like, needle-like, rod-like or long-grained (hereinafter also referred to as “specific shape”). . These specific shaped particles have a ratio of the average major axis to the average minor axis (average major axis / average minor axis) of 1.2 or more and 20 or less. (Average major axis) / (average minor axis) is a so-called aspect ratio. The closer the value is to less than 1.2 and to 1, the closer to a spherical shape. Moreover, the case where it exceeds 20 is made into a fibrous particle shape.

  The shape of the copper oxide particle group will be described with reference to FIG. In FIG. 19, the horizontal axis represents the ratio of the average major axis to the average minor axis (average major axis / average minor axis), and the vertical axis represents the ratio of the average medium diameter to average minor axis (average medium diameter / average minor axis). It is a figure which shows typically the shape distribution of the copper oxide particle in. In FIG. 19, when the average major axis / average minor axis and the average middle diameter / average minor axis are both 1, the shape of the copper oxide particles is spherical. Further, for example, the particle shape when the average medium diameter / average short diameter is a constant value (for example, 1) is long, rod-shaped, and needle-shaped as the average long diameter / average short diameter becomes larger than 1. It is defined as Further, for example, the particle shape when the average major axis / average minor axis is a constant value (for example, 5) is long granular, scaly, and plate-like as the average medium diameter / average minor axis becomes larger than 1. It is defined as In addition, on the definition of a long diameter, a medium diameter, and a short diameter, all of average long diameter / average short diameter, average medium diameter / average short diameter, and average long diameter / average medium diameter are 1 or more.

  The copper oxide particle group of the present invention has an average major axis / average minor axis of 1.2 or more and 20 or less. Therefore, in FIG. 19, the copper oxide particle group of the present invention is a straight line orthogonal to the horizontal axis and having an average major axis / average minor axis of 1.2, and a straight line orthogonal to the horizontal axis and having an average major axis / average minor axis of 20. And a straight line perpendicular to the vertical axis and having an average median diameter / average minor axis of 1 and an average major axis / average minor axis of 1 and an average median diameter / average minor axis of 1 through an inclination (average It belongs to a region surrounded by a straight line having a diameter / average minor axis / (average major axis / average minor axis) of 1.

  The copper oxide particle group of the present invention preferably has an average major axis / average minor axis of 1.2 or more and 20 or less and an average major axis / average median diameter of 2.0 or more. In FIG. 19, the copper oxide particle group in this case is a straight line orthogonal to the horizontal axis and having an average major axis / average minor axis of 1.2, and a straight line orthogonal to the horizontal axis and having an average major axis / average minor axis of 20. And a straight line perpendicular to the vertical axis and having an average median diameter / average minor axis of 1 and an average major axis / average minor axis of 1 and an average median diameter / average minor axis of 1 through an inclination (average median diameter). / Average minor axis) / (average major axis / average minor axis) belongs to a region surrounded by a straight line of ½.

  When the particle shape of the copper oxide particle group constituting the copper oxide paste is a shape close to a sphere, the copper oxide paste is less likely to exhibit thixotropy and screen printing properties tend to be lowered. In addition, when the particle shape is fibrous, the interaction due to the increase in the contact area between the particles becomes stronger, and the particle concentration decreases due to the increase in viscosity, and the thixotropy becomes too large, so that the screen printability is increased. Tends to decrease.

  In the copper oxide particle group, the average major axis / average minor axis is 1.2 or more and 20 or less, but from the viewpoint of printability of the copper oxide paste, the average major axis / average minor axis is 1.5 or more and 15 or less. Is preferably 2 or more and 10 or less. In the copper oxide particle group, from the viewpoint of printability of the copper oxide paste, the average medium diameter / average short diameter is preferably 1 or more and 10 or less, more preferably 1 or more and 8 or less, and more preferably 1 or more and 6 More preferably, it is as follows.

  From the viewpoint of printability of the copper oxide paste, the copper oxide particle group has an average major axis of 100 nm to 1500 nm, an average major axis / average minor axis of 1.5 to 15, and an average medium diameter / average minor axis. Is preferably from 1 to 10, the average major axis is from 100 nm to 1,000 nm, the average major axis / average minor axis is from 2.0 to 10, and the average middle diameter / average minor axis is from 1 to 8. More preferably, the average major axis is 100 nm or more and 600 nm or less, the average major axis / average minor axis is 2.9 or more and 5.5 or less, and the average middle diameter / average minor axis is 1 or more and 6 or less. Further preferred.

  From the viewpoint of printability of the copper oxide paste, the copper oxide particle group preferably has an (average major axis) / (average median diameter) of 2.0 or more, and more preferably 2.2 or more. (Average long diameter) / (Average medium diameter) is {(Average long diameter) / (Average short diameter)} / {(Average medium diameter) / (Average short diameter)}, and the value is 2.0 or more. The shape of the copper oxide particles is long granular or acicular. On the other hand, the shape of the copper oxide particles having a value of less than 2.0 is a scale shape or a plate shape.

  From the viewpoint of printability of the copper oxide paste, the copper oxide particle group has an average major axis of 100 nm to 1500 nm, an average major axis / average minor axis of 1.5 to 15, and an average major axis / average median diameter. Preferably, the average major axis is 100 nm or more and 600 nm or less, the average major axis / average minor axis is 2.9 or more and 5.5 or less, and the average major axis / average median diameter is 2.2 or more. More preferably.

  The copper oxide particle group includes a plurality of copper oxide particles having the specific shape. The number of the copper oxide particles having a specific shape included in the copper oxide particle group is not particularly limited, and is appropriately selected according to the purpose.

  Examples of the copper oxide constituting the copper oxide particles having the specific shape include cuprous oxide and cupric oxide. The copper oxide particles only need to contain at least one of cuprous oxide and cupric oxide, and even if the particles are made of cuprous oxide or particles made of cupric oxide, Any of the particle | grains containing a cuprous oxide and cupric oxide may be sufficient. In addition, the manufacturing method of the said specific shape copper oxide particle is mentioned later.

  The copper oxide particle group may further include other copper oxide particles having a shape different from the specific shape in addition to the copper oxide particles having the specific shape. Examples of other shapes of the copper oxide particles include a substantially spherical shape and a chestnut shape. By including other copper oxide particles, it is possible to improve applicability such as printability, storage stability, conductorization characteristics, conductor layer characteristics, and the like. Specifically, for example, the suitability for application can be adjusted by adding substantially spherical copper oxide particles. Moreover, storage stability improves by adding a chestnut-like copper oxide particle.

  The particle diameter of other copper oxide particles is not particularly limited. For example, the number average particle diameter of the primary particles is preferably 1 nm to 1700 nm, more preferably 1 nm to 1000 nm, and further preferably 10 nm to 500 nm from the viewpoint of the smoothness of the formed metal copper layer. . In particular, the other copper oxide particles preferably have a number average particle diameter of primary particles smaller than the length of the long diameter of the long granular copper oxide particles. Densification of the metal copper layer formed by including other copper oxide particles having a small number average particle diameter of primary particles can be promoted. In addition, the number average particle diameter of the primary particles of other copper oxide particles can be measured by observation using a scanning electron microscope.

  The content rate of the other copper oxide particles in the copper oxide particle group including the copper oxide particles having a specific shape is not particularly limited as long as the effect of the present invention is not impaired, and can be appropriately selected according to the purpose. For example, it can be 30 volume% or less in a copper oxide particle group, and it is preferable that it is 10 volume% or less.

The copper oxide particle group preferably has a carbon atom content of 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1.7% by mass or less. Here, the content of carbon atoms in the copper oxide particle group is 2% by mass or less means that an organic compound such as a surfactant derived from the production method is substantially present in the copper oxide particles constituting the copper oxide particle group. Means it is not included. Using copper oxide particles that are substantially free of organic compounds in the copper oxide particles, a copper oxide paste described below is prepared and applied to a method for producing a conductor pattern to form a lower resistance conductor pattern can do.
For example, the content of carbon atoms contained in the copper oxide particle group is measured by a combustion gas infrared absorption method. Specifically, for example, the measurement is performed under normal conditions using an EMIA-V series manufactured by Horiba, Ltd.

The copper oxide paste may further contain particles of other materials as necessary in addition to the copper oxide particle group. Examples of other material particles include metal copper particles and other metal particles other than copper. Examples of other metal particles include particles of cobalt, nickel, silver, gold, molybdenum, manganese, magnesium, iron, and oxides thereof.
For example, the copper oxide paste can include a metallic copper particle to lower the conductor treatment temperature.

The particle shape of the particles of the other materials is not particularly limited, and examples thereof include a substantially spherical shape, a flat shape, a needle shape, a block shape, a plate shape, and a scale shape. Among these, from the viewpoint of dispersibility, at least one of a substantially spherical shape, a needle shape, and a block shape is preferable.
The particle diameter of particles of other materials is not particularly limited. Among them, the number average particle diameter of the primary particles is preferably 1 nm to 1000 nm, more preferably 1 nm to 500 nm, and further preferably 10 nm to 100 nm from the viewpoint of the smoothness of the formed metal copper layer. . In addition, the particle diameter of the particle | grains of other materials can be measured by observation using a scanning electron microscope.

  The said copper oxide paste can be suitably selected according to the method of providing a copper oxide paste. For example, when used for screen printing, the content of all particles including the copper oxide particle group and particles of other materials included as necessary is preferably 30% by mass or more and 80% by mass or less, and 50% by mass. The content is more preferably 75% by mass or less, and further preferably 60% by mass or more and 75% by mass or less. Further, the content of the copper oxide particles in all particles is preferably 50% by mass or more, and preferably 60% by mass or more from the viewpoint that a dense metallic copper layer with low resistance is obtained after the conductor treatment. Is more preferable, and it is still more preferable that it is 70 mass% or more. It can select suitably according to the method of providing a paste.

  Furthermore, the copper oxide paste has a content ratio of all the particles including the copper oxide particle group of 30% by mass or more and 80% by mass or less from the viewpoint that a dense metallic copper layer with low resistance is obtained after the conductor treatment. The content of the copper oxide particles in the particles is preferably 50% by mass or more, the content of all the particles is from 50% by mass to 75% by mass, and the content of the copper oxide particles in all the particles is More preferably, the content is 60% by mass or more, the content of all particles is 60% by mass or more and 75% by mass or less, and the content of the copper oxide particles in all the particles is 70% by mass or more. .

(Dispersion medium)
The dispersion medium preferably contains at least one organic solvent. The organic solvent preferably has a vapor pressure at 25 ° C. of less than 1.34 × 10 ³ Pa, more preferably less than 1.0 × 10 ³ Pa.

  Examples of such an organic solvent include those shown below. That is, aliphatic hydrocarbon solvents such as nonane, decane, dodecane, and tetradecane; aromatic solvents such as ethylbenzene, anisole, mesitylene, naphthalene, cyclohexylbenzene, diethylbenzene, phenylacetonitrile, benzonitrile; isobutyl acetate, methyl propionate, Ester solvents such as ethyl propionate, γ-butyrolactone, glycol sulfite, ethyl lactate; alcohol solvents such as 1-butanol, cyclohexanol, α-terpineol, glycerin; cyclohexanone, 2-hexanone, 2-heptanone, Ketone solvents such as 2-octanone, 1,3-dioxolan-2-one, 1,5,5-trimethylcyclohexen-3-one; diethylene glycol ethyl ether, diethylene glycol diethyl Ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol propyl ether acetate, diethylene glycol isopropyl ether acetate, diethylene glycol butyl ether acetate, diethylene glycol -T-butyl ether acetate, triethylene glycol methyl ether acetate, triethylene glycol ethyl ether acetate, triethylene glycol propyl ether acetate, triethylene glycol isopropyl ether acetate Alkylene glycol solvents such as triethylene glycol butyl ether acetate, triethylene glycol-t-butyl ether acetate, dipropylene glycol dimethyl ether, dipropylene glycol monobutyl ether; dihexyl ether, butyl phenyl ether, pentyl phenyl ether, methoxy toluene, benzyl ethyl ether, etc. Ether solvents such as propylene carbonate and ethylene carbonate; amide solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone; sulfone solvents such as sulfolane; malononitrile and the like Nitrile solvents can be exemplified. Among these, at least one selected from γ-butyrolactone, N-methylpyrrolidone, glycol sulfite, propylene carbonate, and sulfolane is preferable. These solvents can be used alone or in combination of two or more.

The copper oxide paste may further contain additives such as a dispersant, a surface protective agent, a thickener, and a thixotropic agent, as necessary. When the copper oxide paste contains an additive, the content of the additive that is non-volatile or non-decomposable at a temperature of 200 ° C. or less is preferably 20% by mass or less, and more preferably 5% by mass or less. More preferably, it is 1 mass% or less. When the content of the additive is within the above range, a conductor having a volume resistivity of 1 × 10 ⁻⁷ Ω · m or less can be easily formed at a low temperature of 200 ° C. or less. Moreover, it can suppress that the void resulting from the residue of an additive generate | occur | produces in the metal copper layer formed.

  The maximum particle size in the dispersed state of the particles contained in the copper oxide paste can be appropriately selected according to the line width of the metal copper layer pattern to be formed. For example, the maximum particle size is preferably 1/10 or less of the line width to be formed, and more preferably 1/20 or less. Thereby, generation | occurrence | production of shape disorder and fading of the linear pattern to form can be suppressed. For the same reason, the volume average particle size in the dispersed state is preferably 1/15 or less of the line width, and more preferably 1/30 or less. Therefore, when forming a thin wire having a line width of 70 μm that is generally used for wiring board applications, the maximum particle size in a dispersed state of the particles is preferably 7 μm or less, more preferably 3.5 μm or less. . Further, the volume average particle size in the dispersed state of the particles is preferably 4.7 μm or less, more preferably 1.5 μm or less. Furthermore, when forming a pattern with a line width of 25 μm used for high-definition applications such as a mounting substrate, the maximum particle size in a dispersed state of the particles is preferably 2.5 μm or less, more preferably 1.3 μm or less. It is. Further, the volume average particle size in the dispersed state of the particles is preferably 1.7 μm or less, more preferably 0.8 μm or less.

  Here, the volume average particle size and the maximum particle size are measured by a photon correlation method based on a dynamic light scattering method by Brownian motion of particles. The volume average particle diameter and the maximum particle diameter can be measured using, for example, “Submicron Particle Analyzer N5 Type” (trade name) manufactured by Beckman Coulter, Inc.

  When the copper oxide paste is applied to the screen printing method, from the viewpoint of fine line drawing and print reproducibility, the Casson equilibrium viscosity measured by a viscoelasticity measuring device equipped with a cone plate is 0.01 Pa · s or more and 200 Pa · It is preferably s or less, more preferably 0.1 Pa · s or more and 200 Pa · s or less, and further preferably 1 Pa · s or more and 200 Pa · s or less.

When the copper oxide paste is applied to an ink jet method, the dynamic viscosity at 25 ° C. is preferably 5 mPa · s to 100 mPa · s, and more preferably 5 mPa · s to 50 mPa · s. When the dynamic viscosity is 5 mPa · s or more, it is possible to suppress mist from being ejected from the nozzle. In addition, the applied shape after landing on the insulating layer is well maintained. On the other hand, when it is 100 mPa · s or less, the discharge property becomes better. The “dynamic viscosity at 25 ° C.” is, in other words, the shear viscosity at a measurement temperature of 25 ° C. and a shear rate of 10 / sec.
The dynamic viscosity of the copper oxide paste can be measured by, for example, a dynamic viscoelasticity measuring device equipped with a cone plate jig.

  The copper oxide paste can be prepared, for example, by dispersing the copper oxide particle group and other particles included as necessary in a dispersion medium. Dispersion treatment includes Ishikawa-type stirrer, rotation-revolution stirrer, ultra-thin high-speed rotary disperser, media disperser such as roll mill, ultrasonic disperser, bead mill, cavitation stirrer such as homomixer and silverson stirrer, Artema An opposing collision method such as Iser can be used. Moreover, you may use combining these methods suitably.

  Moreover, in preparation of a copper oxide paste, you may perform the process which removes a coarse grain after a dispersion process. As a method for removing coarse particles, filtration, centrifugation, mesh permeation, water sieving, and the like can be used. For example, when the application of the copper oxide paste is performed by screen printing, if coarse particles larger than the screen openings are included, printing failure may be caused. Therefore, it is preferable to perform a coarse particle removal process. Note that coarse particles that may cause printing failure during printing can be confirmed with a grind meter.

(Method for producing copper oxide particles)
The copper oxide particles having the specific shape include, for example, a step of heat-treating a water-containing composition containing copper hydroxide and having a pH of 6.0 to 11.0 to produce copper oxide. It can manufacture with the manufacturing method containing a process. The said copper oxide particle group comprised from the copper oxide particle which has a desired shape can be efficiently manufactured by heat-processing the hydrous composition containing copper hydroxide in a specific pH range.

  The water-containing composition containing copper hydroxide may be an aqueous composition containing copper hydroxide, and the mode of copper hydroxide contained is not particularly limited. The water-containing composition may contain copper hydroxide in a solution state or in a suspended state. In the said water-containing composition, it is preferable that at least one part of copper hydroxide is contained in the solution state.

  The content of copper hydroxide contained in the water-containing composition is not particularly limited, and is appropriately selected according to the production conditions of the copper oxide particle group. Among these, from the viewpoint of the production efficiency of the copper oxide particle group, the copper ion concentration in the water-containing composition is preferably 0.01 mol / kg to 0.15 mol / kg, preferably 0.015 mol / kg to 0.13 mol / kg. kg is more preferable, and 0.02 mol / kg to 0.10 mol / kg is further preferable.

The pH of the water-containing composition in the production method is 6.0 or more and 11.0 or less, but from the viewpoint of efficiently obtaining copper oxide particles having a desired aspect ratio, it is 6.0 or more and 8.5 or less. It is preferably 6.5 or more and 8.3 or less, more preferably 7.0 or more and 8.0 or less.
In general, when a water-containing composition containing copper hydroxide is subjected to a heat treatment under the condition that the pH is less than 6, massive copper oxide particles are generated. In addition, fibrous copper oxide particles are produced when heat-treated under a condition where the pH exceeds 11.0, but specific shapes of copper oxide particles having a desired aspect ratio can be obtained by heat-treating at pH 6.0 or higher and 11.0 or lower. Can be obtained. Furthermore, long granular copper oxide particles having a desired aspect ratio can be obtained by heat treatment at a pH of 6.0 or more and 8.5 or less.

  Adjustment of pH of a water-containing composition can be performed by a conventional method using a water-soluble base or its aqueous solution. Examples of water-soluble bases include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal salts of phosphoric acid such as potassium diphosphate; alkoxides such as sodium methoxide and potassium ethoxide Can be mentioned.

  The method for measuring the pH of the water-containing composition is not particularly limited, and can be measured by a commonly used means. For example, it can be measured with a pH meter (for example, a personal pH / ORP meter manufactured by Yokogawa Electric Corporation). As a measured value of pH, a standard buffer solution (phthalate pH buffer solution, pH: 4.01 (25 ° C.), neutral phosphate pH buffer solution, pH: 6.86 (25 ° C.)) was used. After two-point calibration, the electrode is put in the water-containing composition, and the value after 1 minute or more has elapsed and adopted.

  Moreover, the temperature of heat processing will not be restrict | limited especially if the copper hydroxide contained in a water-containing composition can be converted into a copper oxide. From the viewpoint of the production efficiency of the copper oxide particle group, it is preferably 60 ° C. or higher and 110 ° C. or lower, more preferably 60 ° C. or higher and 100 ° C. or lower, and further preferably 70 ° C. or higher and 95 ° C. or lower. When the temperature of the heat treatment is 60 ° C. or higher, the conversion reaction from copper hydroxide to copper oxide proceeds efficiently. Moreover, since it does not exceed the boiling point of the said water-containing composition as it is 110 degrees C or less, productivity is improved without requiring a pressure-resistant container etc.

  The heating method is not particularly limited as long as the water-containing composition can be heated to a desired temperature, and can be appropriately selected from commonly used heating means. Examples of heating means include hot air dryers, thermostats, hot plates, throwing heaters, ceramic heaters, pipe heaters, resistance heating, infrared heating, steam heating, induction heating, microwave heating, laser heating, flame, etc. Can be mentioned.

  It is preferable that the manufacturing method further includes a step of obtaining a water-containing composition containing the copper hydroxide by adding a basic compound to the copper complex aqueous solution. Thereby, the water-containing composition containing copper hydroxide having a desired pH can be obtained more efficiently.

The copper complex contained in the aqueous copper complex solution is preferably a water-soluble copper complex composed of a divalent copper ion and a ligand. Here, the water-soluble copper complex means 5% by mass or more dissolved in pure water. The water-soluble copper complex is not particularly limited as long as it can produce copper oxide particles at a pH of 6.0 or more and 11.0 or less. Even if it is an organic acid copper complex having an organic acid base as a ligand, it is inorganic. It may be an inorganic copper complex having an acid base as a ligand.
Examples of the organic acid copper salt forming the organic acid copper complex include copper acetate, copper formate, copper oxalate, copper glyoxylate, copper citrate, and copper propionate. Examples of the inorganic acid copper salt that forms the inorganic copper complex include copper nitrate, copper carbonate, copper chloride, copper iodide, and copper bromide. Among these, from the viewpoint of production efficiency of copper oxide particles, an organic acid copper salt is preferable, and at least one selected from copper acetate and copper formate is more preferable.

  The water-containing composition can further include at least one alcohol. The particle diameter of the copper oxide particle produced | generated by including alcohol can be reduced in diameter. The alcohol is not particularly limited as long as it is a water-soluble compound having an alcoholic hydroxy group. Here, water-soluble means that 10% by mass or more dissolves in pure water. The alcohol may be a monoalcohol or a polyhydric alcohol. Especially, it is preferable that it is a C1-C8 water-soluble alcohol, It is more preferable that it is a C1-C6 water-soluble alcohol, It is further more preferable that it is a C1-C4 water-soluble alcohol.

  Specific examples of the alcohol include methanol, ethanol, 2-propanol, 1-propanol, 1-butanol, 2-butanol, t-butyl alcohol, cyclobutanol, 1-pentanol, 2-pentanol, cyclopentanol, Cyclobutanemethanol, 1-hexanol, diethylene glycol, 1,2-propanediol, 2-methoxyethanol, 1,3-propanediol, propylene glycol, 2,2-dimethyl-1,3-propanediol, 1,5-pentanediol Dihydroxyacetone, 2,3-butanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,4-pentanediol, 1,5-pentanediol, 1,2- Pentanediol, glycerin, 4-H Roxy-2-butanone, 3-hydroxy-2-butanone, 3-hydroxytetrahydrofuran, 3-methyl-1-butanol, 3-methyl-2-butanol, 2-methyl-1-butanol, 2-methyl-2-butanol 2,2-dimethyl-1-propanol, 1-methoxy-2-propanol, 2-ethoxyethanol, 3-methoxy-1-propanol, hydroxygammabutyrolactone, tetrahydrofurfuryl alcohol, tetrahydropyran-2-ol, 3- Acetyl-1-propanol, methyl butyrate, ethyl glycolate, 4-methyl-1-butanol, 3-ethyl-1-propanol, 3-methoxy-1,2-propanediol, glycolaldehyde dimethyl acetal, diethylene glycol, 1,2 , 4-butant All, γ-hydroxymethyl-γ-butyrolactone, 1,3-cyclohexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, threose, 1,4-dioxane-2,3-diol, 1,4- Examples include dioxane-2,5-diol and inositol.

  When the said water-containing composition contains alcohol, the content rate of alcohol can be suitably selected according to the kind and desired particle diameter of alcohol. For example, it can be made into 10 mass%-50 mass% in a water-containing composition, and it is preferable that it is 20 mass%-40 mass%. When the content is 10% by mass or more, the particle diameter of the produced copper oxide particles can be effectively reduced. Moreover, it can suppress that the solubility of a water-soluble copper complex falls that it is 50 mass% or less, and it becomes easy to achieve a desired copper ion concentration. When alcohol is added to the water-containing composition, the order of addition is not particularly limited. For example, it may be before pH adjustment or after pH adjustment. Moreover, you may use the said alcohol individually by 1 type or in combination of 2 or more types.

  It is preferable that the manufacturing method further includes a washing step of removing at least a part of the ionic compound after the step of producing copper oxide. Thereby, when a copper oxide paste is comprised and it applies to the manufacturing method of a metal copper layer, a metal copper layer pattern of higher definition and lower resistance can be formed.

  The method used for the washing step can be appropriately selected from commonly used washing methods as long as at least part of the ionic compound contained in the water-containing composition can be removed after the production of the copper oxide particles. Specific examples of the washing method include ultrafiltration, microfiltration, centrifugation, dialysis, pure water washing, ion exchange resin treatment, and the like. Among these, from the viewpoint of washing efficiency, it is preferable to use at least one selected from the group consisting of ultrafiltration, microfiltration, centrifugation, dialysis, and pure water washing. The cleaning method may be used singly or in combination of two or more.

  In the cleaning step, the cleaning liquid used is not particularly limited. Of these, ion-exchanged water and purified water are preferred. Moreover, the said washing | cleaning process should just remove at least one part of an ionic compound. From the viewpoint of the low resistance of the conductor pattern to be formed and the dispersion stability of the copper oxide paste, it is preferable that the electrical conductivity of the cleaning liquid (preferably water) used in the cleaning method is 5000 mS / m or less. It is more preferable to carry out so that it may become 1000 mS / m or less.

<Method for producing metal copper layer>
The method for producing a copper metal layer according to the present invention includes a pattern forming step of forming a copper oxide particle-containing layer by applying the copper oxide paste on a support, and conducting the copper oxide particle-containing layer by conducting a conductor. A conductive layer forming step for forming a copper layer, and other steps as necessary. By forming the copper oxide particle-containing layer in a desired pattern, it is possible to form a dense conductor pattern having excellent electrical and thermal conductivity in a desired shape.

  The support for forming the metal copper layer is not particularly limited, and can be appropriately selected from insulating materials that are usually used according to the purpose. Examples thereof include inorganic materials such as glass and ceramics, and organic materials used for wiring boards. In particular, when conducting a conductorization process described below at a low temperature of 200 ° C. or lower, the range of selection of applicable organic materials is expanded. When a film-like flexible support is used, a flexible and lightweight device can be configured.

  The method for forming the copper oxide particle-containing layer by patterning the copper oxide paste on the support is not particularly limited as long as the copper oxide particle-containing layer can be formed at an arbitrary location. Examples of such methods include inkjet method, super inkjet method, screen printing method, transfer printing method, offset printing method, reverse offset printing method, jet printing method, dispenser method, jet dispenser method, needle dispenser method, comma coater method, slit Coater method, die coater method, gravure coater method, letterpress printing method, intaglio printing method, gravure printing method, soft lithographic method, dip pen lithographic method, particle deposition method, spray coater method, spin coater method, dip coater method, electrodeposition coating method Etc. Among them, from the group consisting of inkjet method, super inkjet method, screen printing method, offset printing method, reverse offset printing method, jet printing method, dispenser method, needle dispenser method, comma coater method, slit coater method, die coater method and gravure coater method At least one selected method is preferable, and since a pattern having a line width of 70 μm or less can be formed, the method includes a super ink jet method, a screen printing method, a reverse offset printing method, a dispenser method, and a needle dispenser method. More preferably, it is at least one method selected from the group. The method of patterning the copper oxide particle-containing layer may be used singly or in combination of two or more.

  The shape of the copper oxide particle-containing layer formed on the insulating layer is not particularly limited and can be appropriately selected according to the purpose. Moreover, the layer thickness of the said copper oxide particle content layer is not restrict | limited in particular, According to the objective, it can select suitably. For example, the thickness may be 0.2 μm to 50 μm, and is preferably 0.8 μm to 20 μm from the viewpoint of conductivity and connection reliability.

  The said manufacturing method may further have the drying process which removes at least one part of the dispersion medium contained in the copper oxide paste after copper oxide paste provision. By drying the applied copper oxide paste, the fluidity of the copper oxide paste is lowered and the shape is stabilized. Moreover, the influence on a conductor process can be suppressed because the residual dispersion medium in the subsequent conductor process process reduces. The drying step is not particularly limited as long as at least a part of the dispersion medium can be removed. For example, a method of drying by heating, decompression or blowing can be used. Devices that can be applied to such a method include a hot air dryer, a vacuum dryer, a vacuum oven, a thermostatic bath, and a blower. The drying temperature can be 30 ° C. to 200 ° C. and the drying time is 0.1 hour to 2.0 hours.

  In the conductor treatment process, the formed copper oxide particle-containing layer is conductorized to form a metal copper layer. There are no particular limitations on the method of conductorization as long as copper oxide can be reduced to metallic copper. Among these, a method of heat treatment in a formic acid-containing atmosphere is preferable from the viewpoint of the denseness of the formed metal copper layer. By using formic acid gas, a dense metal copper film is generated, and a metal copper layer having a low volume resistivity and high thermal conductivity can be formed.

  The concentration of formic acid in the formic acid-containing atmosphere used for the conductor treatment is not particularly limited as long as copper oxide can be reduced. For example, it can be set to 0.01 g / L to 2 g / L. The formic acid-containing atmosphere may contain other gas components other than formic acid gas. Other gas components are not particularly limited as long as they do not react with formic acid. When oxygen is contained as another gas component, the mixing ratio of oxygen and formic acid is preferably outside the explosion range. Specifically, when formic acid and air are mixed, the concentration of formic acid is preferably 18% by volume or less or 51% by volume or more.

  The method for generating formic acid gas is not particularly limited. For example, a method of supplying nitrogen gas containing formic acid gas to liquid formic acid and providing it to the copper oxide particle-containing layer that is the object to be treated, heating to a boiling point of formic acid of 100 ° C. or higher, or reducing the pressure to form a gaseous state The method of providing to a to-be-processed object can be mentioned after making it.

  Moreover, the temperature of heat processing should just be 120 degreeC or more which metal copper precipitates from copper oxide in presence of formic acid gas, and it is preferable that it is 140 degreeC or more from a viewpoint of a processing speed. The upper limit of processing temperature is prescribed | regulated by the heat-resistant temperature of the support body (for example, board | substrate) which forms a metal copper layer pattern. Further, the treatment pressure may be any of atmospheric pressure, reduced pressure, and increased pressure without particular limitation.

  It is preferable that the manufacturing method of the said metallic copper layer further has the plating process process of carrying out the electrolytic plating process or the electroless-plating process to the metallic copper layer formed at the conductor process process. Thereby, a metal copper layer having a desired film thickness can be formed, and a thick film fine wiring can be formed efficiently. When the electroless plating process is performed, the metal copper layer formed in the conductor process step functions as a seed layer, for example. Moreover, when performing an electroplating process, the metal copper layer formed at the conductor-conducting process functions, for example, as an ultrathin copper layer.

  Since the metal copper layer formed as described above is dense and excellent in electrical conductivity and thermal conductivity, it is suitable for use in conductor wiring, electrodes, thermal conduction paths, and heat dissipation. In addition, the conductor pattern formed in this way can be used as a seed layer for electroless plating or an ultrathin copper layer for electrolytic plating when forming a thick neck rewiring.

<Conductor wiring>
The conductor wiring of this invention will not be restrict | limited especially if the metal copper layer obtained with the manufacturing method of the said metal copper layer is included. By including the metal copper layer, the electrical conductivity is excellent. The conductor wiring is, for example, a metal copper layer patterned in a desired shape on an insulating layer that is a support, and can be applied to other uses.

<Electrode>
The electrode of this invention will not be restrict | limited especially if the metal copper layer obtained with the manufacturing method of the said metal copper layer is included. By including the metal copper layer, the electrical conductivity is excellent. The electrode can be applied to, for example, an RFID antenna wiring.

<Heat conduction path>
The heat conduction path of the present invention is not particularly limited as long as it includes the metal copper layer obtained by the method for producing the metal copper layer. By including the metal copper layer, the thermal conductivity is excellent. The heat conduction path can be applied to uses such as a thermal via of a power device, for example.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

[Production Example 1]
Anhydrous copper acetate (II) 3.4 g (concentration 0.022 mol / kg during heating) was dissolved in 680 g of pure water to obtain a copper complex solution. Sodium hydroxide was dissolved in pure water at 1.0 mol / kg to obtain a pH adjuster. In a 1 L polypropylene bottle, the total amount of the copper complex solution and 140.1 g of the pH adjusting agent were mixed and sealed, and shaken by hand to obtain a water-containing composition containing copper hydroxide. It was 7.3 when pH was measured.
The mixture was sealed in a bottle and heated in a thermostat at 90 ° C. for 5 hours to obtain a black precipitate.

  After cooling to room temperature, the supernatant was removed and the black powder was separated with a centrifuge (11000 rpm, 10 min). After adding 400 ml of pure water to the separated black powder and applying it to an ultrasonic cleaner, the operation of separating the black powder with a centrifuge (11000 rpm, 15 min) was repeated twice for washing. The washed black powder was dried in a thermostat at 90 ° C. for 5 hours to obtain a copper oxide particle group. Yield 1.0 g (65% yield)

  As a result of observation of the copper oxide particle group by a scanning electron microscope (SEM), as shown in FIG. 1, it was long granular particles having an average major axis of 400 nm and an average minor axis of 110 nm. The average major axis and the average minor axis were measured for 20 copper oxide particles and calculated as the arithmetic average thereof. The aspect ratio (average major axis / average minor axis), which is the ratio of the average major axis to the average minor axis, is 3.6, the average middle diameter / average minor axis is 1.0, and the average major axis / average middle diameter is 3. .6. The major axis variation coefficient was 14.5%, and was obtained by dividing the standard deviation of the major axis length by the average value.

As a result of X-ray diffraction (XRD) measurement, as shown in FIG. 3, the copper oxide particles were a mixed phase of cupric oxide and cuprous oxide.
Furthermore, the oxygen content contained in the dried copper oxide particles measured by an inert gas melting-infrared absorption method (measuring device: EMIA-920V, manufactured by Horiba, Ltd.) was 18.54% by mass. Moreover, the carbon content contained in the dry copper oxide particles measured by the combustion gas infrared absorption method (measuring device: EMGA-930, manufactured by Horiba, Ltd.) was 1.45% by mass.

[Production Example 2]
In Production Example 1, copper oxide particles were prepared in the same manner as in Production Example 1 except that ethanol was added to a water-containing composition containing copper hydroxide so as to be 20% by mass. At this time, the pH after shaking by hand was 7.6. The yield of the obtained copper oxide particles was 1.2 g (yield 78%).

  The result of observation by SEM of the obtained copper oxide particle group is shown in FIG. Further, the particles were long granular particles having an average major axis of 150 nm and an average minor axis of 30 nm, which were smaller than the copper oxide particle group obtained in Production Example 1. The average major axis / average minor axis was 5.0, the average middle diameter / average minor axis was 1.0, and the average major axis / average middle diameter was 5.0.

As a result of the XRD measurement, as shown in FIG. 3, the copper oxide particles were composed mainly of cupric oxide.
The oxygen content contained in the dry copper oxide particles measured by the inert gas melting-infrared absorption method is 19.4% by mass, and the carbon content contained in the dry copper oxide particles measured by the combustion gas infrared absorption method is The amount was 1.61% by mass.

[Production Example 3]
In Production Example 1, copper oxide particles were prepared in the same manner as in Production Example 1 except that ethanol was added to a water-containing composition containing copper hydroxide so as to be 40% by mass. At this time, the pH after shaking by hand was 7.7. The yield of the obtained copper oxide particles was 1.2 g (yield 78%).

  As a result of observation by SEM of the obtained copper oxide particles, they were long granular particles having an average major axis of 120 nm and an average minor axis of 30 nm, which were smaller than the copper oxide particle group obtained in Production Example 1. Further, the average major axis / average minor axis was 4.0, the average middle diameter / average minor axis was 1.0, and the average major axis / average middle diameter was 4.0.

As a result of the XRD measurement, as shown in FIG. 3, the copper oxide particles were composed mainly of cupric oxide.
The oxygen content contained in the dry copper oxide particles measured by the inert gas melting-infrared absorption method is 19.5% by mass, and the carbon content contained in the dry copper oxide particles measured by the combustion gas infrared absorption method is 1.49% by mass

[Production Examples 4 to 6]
In Production Example 1, the amount of anhydrous copper acetate (II) added was 5.0 g (0.033 mol / kg), 6.8 g (0.054 mol / kg), and 13.6 g (0.090 mol / kg), respectively. Except that, copper oxide particles were synthesized in the same manner.
As a result, particles having substantially the same particle diameter were obtained regardless of the concentration of the raw material copper complex at the time of synthesis. The synthesis results are summarized in the table below. Moreover, the result of the observation by SEM of the copper oxide particle group obtained in Production Example 4 is shown in FIG.
In addition, pH after pH adjuster addition was 7.1, 7.4, and 7.6, respectively.
Furthermore, the carbon content contained in the dry copper oxide particles measured by the combustion gas infrared absorption method was 1.33% by mass, 1.41% by mass and 1.38% by mass, respectively.

[Production Example 7]
In Production Example 1, copper oxide particles were similarly prepared except that 184 g of the pH adjuster was mixed. At this time, the pH after shaking by hand was 12.7. The yield was 5 g (89% yield).
As a result of SEM observation of the copper oxide particles, it was a ribbon-like particle shape as shown in the SEM photograph in FIG. Moreover, it was a mixture of particle shapes having various sizes, and ribbon-shaped particles overlapped. The average major axis calculated from 20 arbitrarily selected copper oxide particles was 734 nm, and the variation coefficient of the major axis was 33.7%. The average major axis / average minor axis was 73.4, the average middle diameter / average minor axis was 25.3, and the average major axis / average middle diameter was 2.9.

[Production Examples 8 to 10]
In Production Example 1, 3.4 g of anhydrous copper acetate (II) was dissolved in 170 g of pure water, and a pH adjuster was added while measuring the pH so that the predetermined pH shown in the table below was obtained. Copper oxide particles were synthesized in the same manner except that the concentration was adjusted to 0.022 mol / kg. The synthesis results are summarized in the table below. Moreover, the result of the observation by SEM of a copper oxide particle group is shown in FIGS. FIG. 6 shows a group of copper oxide particles obtained in Production Example 8. FIG. 7 shows the copper oxide particle group obtained in Production Example 9. FIG. 8 shows the copper oxide particle group obtained in Example 10.

[Production Example 11]
Copper (II) nitrate was dissolved in pure water to obtain a 1.0 mol / L copper complex solution. Sodium hydroxide was dissolved in pure water to obtain a 2.0 mol / L pH adjusting solution. In a 200 mL polypropylene bottle, 100 mL pure water, 20 mL of a copper complex solution and 20 mL of a pH adjusting solution were mixed and sealed, and then shaken by hand to obtain a water-containing composition containing copper hydroxide. It was 6.4 when pH was measured.
This mixed solution was left in a thermostatic chamber at 20 ° C. for 9 hours while being sealed in a bottle to obtain a black precipitate.
The supernatant was removed at room temperature and the black powder was separated with a centrifuge (11000 rpm, 10 min). After adding 400 ml of pure water to the separated black powder and applying it to an ultrasonic cleaner, the operation of separating the black powder with a centrifuge (11000 rpm, 15 min) was repeated twice for washing. The washed black powder was dried in a thermostat at 90 ° C. for 5 hours to obtain a copper oxide particle group. Yield 1.68 g (18.9% yield).
As a result of the operation electron microscope (SEM) observation of the copper oxide particle group, the particles were long granular particles having an average major axis of 320 nm and an average minor axis of 21 nm. The average major axis / average minor axis was 15.2, the average middle diameter / average minor axis was 3.0, and the average major axis / average middle diameter was 5.0.

[Production Example 12]
Copper (II) nitrate was dissolved in pure water to obtain a 0.10 mol / L copper complex solution. Sodium hydroxide was dissolved in pure water to obtain a pH adjusting solution of 0.20 mol / L. In a 200 mL polypropylene bottle, 100 mL pure water, 20 mL of a copper complex solution and 20 mL of a pH adjusting solution were mixed and sealed, and then shaken by hand to obtain a water-containing composition containing copper hydroxide. It was 6.4 when pH was measured.
When this mixed solution was left sealed in a bottle at 20 ° C. for 5 days while being sealed in a bottle, a black precipitate was obtained.
The supernatant was removed at room temperature and the black powder was separated with a centrifuge (11000 rpm, 10 min). After adding 400 ml of pure water to the separated black powder and applying it to an ultrasonic cleaner, the operation of separating the black powder with a centrifuge (11000 rpm, 15 min) was repeated twice for washing. The washed black powder was dried in a thermostat at 90 ° C. for 5 hours to obtain a copper oxide particle group.
As a result of the operation electron microscope (SEM) observation of the copper oxide particle group, the particles were long granular particles having an average major axis of 206 nm and an average minor axis of 77 nm. Further, the average major axis / average minor axis was 2.7, the average middle diameter / average minor axis was 1.3, and the average major axis / average middle diameter was 2.1.
The synthesis results are summarized in the table below. In Table 1, “-” means not evaluated.

[Example 1]
(Preparation of copper oxide paste)
25 g of the copper oxide particles obtained in Production Example 1 were weighed into a plastic container, and 25 g of terpineol (vapor pressure at 20 ° C .: 24 Pa) was added so that the solid content was 50% by mass to obtain a mixed solution. After stirring this with a stirrer manufactured by Shinky Co., Ltd. (Awatori Nertaro ARE-310), using an ultrasonic homogenizer US-600CCVP manufactured by Nippon Seiki Seisakusho while cooling in a water bath, an ultrasonic terminal depth of about 3 cm / output 600 W / Dispersion treatment was performed for a total of 7 minutes while stirring with a spatula at a frequency of 19.5 kHz / amplitude of 26.5 μm. After the dispersion treatment, foreign matter was removed through a nylon mesh (aperture 100 μm), and then the contents were transferred to a plastic bottle with a lid and cooled at room temperature to obtain a copper oxide paste.
When the equilibrium viscosity of Casson was measured using a viscoelasticity measuring device (MCR-301, manufactured by Anton Paar) equipped with a cone plate, it was 0.09 Pa · s.

(Screen printing and conductorization)
The prepared copper oxide paste was applied onto a PEN film (polyethylene naphthalate film, film thickness 125 μm) using a nylon mesh printing plate (310 mesh, L / S = 100 μm / 100 μm) and a hand-printed screen printer. . The test piece in which the pattern of the copper oxide particle content layer was formed was dried for 15 minutes on a 180 degreeC hotplate. The obtained test piece was observed with a microscope and evaluated according to the following evaluation criteria.

(Evaluation criteria)
A: When printing with a printing plate of L / S = 100 μm / 100 μm, printing was possible without short circuit.
B: When printing with a printing plate of L / S = 100 μm / 100 μm, a blur occurred and the line was broken.
C: When printing with a printing plate of L / S = 100 μm / 100 μm, bleeding occurred and a line short-circuited.

  The formed copper oxide particle-containing layer pattern had L / S = 165 μm / 35 μm and a wiring height of 3.0 μm. The enlarged photograph of the copper oxide particle content layer pattern formed in FIG. 13 was shown. There was no contact (short) between the printed copper oxide particle-containing layer patterns, and the copper oxide particle-containing layer patterns were independently formed, and the printability was good.

The test piece obtained above was treated with formic acid gas under the treatment conditions of a sample temperature of 175 ° C., a formic acid gas temperature of 60 ° C., and a treatment time of 1 hour to form a conductor layer.
The surface resistance of the obtained conductor layer was 2.1 × 10 ⁻² Ω / □. Moreover, when this was subjected to FIB cross-section processing and SIM observation, the average film thickness was 690 nm. FIG. 17 shows a SIM photograph. The surface resistance of the conductor layer was measured by a 4-terminal 4-probe method using a low resistivity meter (Loresta-GP (MCP-T610) manufactured by Mitsubishi Chemical Corporation).

[Examples 2 to 11]
In Example 1, copper oxide particles obtained in Production Examples 2 to 6 and 8 to 12 were used in the same manner as in Example 1 except that the copper oxide particles obtained in Production Examples 1 to 6 and 8 to 12 were used in place of the copper oxide particles obtained in Production Example 1. Each paste was prepared. Screen printing and conductorization treatment were performed in the same manner as in Example 1 except that the obtained copper oxide paste was used, and evaluation was performed in the same manner.
[Example 12]
In Example 1, instead of the copper oxide particles obtained in Production Example 1, rod-shaped copper oxide particles (manufactured by Chemilite; copper oxide nanoparticles, average major axis 845 nm, major axis variation coefficient 8.1%, average minor axis 115 nm, Copper oxide in the same manner as in Example 1 except that average major axis / average minor axis = 7.3, average middle diameter / average minor axis = 3.0, and average major axis / average middle diameter = 2.4). Each paste was prepared. Screen printing and conductorization treatment were performed in the same manner as in Example 1 except that the obtained copper oxide paste was used, and evaluation was performed in the same manner.

[Example 13]
In Example 1, the copper oxide paste was prepared like Example 1 except having changed the compounding quantity of terpineol so that solid content might be 60 mass%.

(Screen printing)
The prepared copper oxide paste was applied onto a PEN film (polyethylene naphthalate film, film thickness 125 μm) using a nylon mesh printing plate (400 mesh, L / S = 50 μm / 50 μm) and a hand-printed screen printer. . The test piece in which the pattern of the copper oxide particle content layer was formed was dried for 15 minutes on a 180 degreeC hotplate. The obtained test piece was observed with a microscope and evaluated according to the following evaluation criteria.

(Evaluation criteria)
A °: L / S = 50 μm / 50 μm When printing with a printing plate, printing was possible without a short circuit.
B.degree .: L / S = 50 .mu.m / 50 .mu.m When printing on a printing plate, scraping occurred and the line was broken.
C.degree .: L / S = 50 .mu.m / 50 .mu.m When printing on a printing plate, bleeding occurred and the lines were short-circuited.

  The formed copper oxide particle-containing layer pattern had L / S = 73 μm / 27 μm and a wiring height of 4.7 μm. Moreover, the enlarged photograph of the copper oxide particle content layer pattern formed in FIG. 14 was shown. As shown in FIG. 14, the copper oxide particle-containing layer patterns were formed independently without contacting (shorting) with each other, the printability was good, and the evaluation was A °.

[Comparative Example 1]
In Example 1, a copper oxide paste was prepared in the same manner as in Example 1 except that the copper oxide particles obtained in Production Example 7 were used instead of the copper oxide particles obtained in Production Example 1.
Screen printing was performed in the same manner as in Example 1 except that the obtained copper oxide paste was used, and evaluation was performed in the same manner. There was a contact (short) between the formed copper oxide particle-containing layers, and the lines were broken due to creaking, so that the printability of the copper oxide particle-containing layer pattern was poor.

[Comparative Example 2]
In Example 1, instead of the copper oxide particles obtained in Production Example 1, spherical copper oxide particles (manufactured by CI Kasei Co., Ltd .; copper oxide nanoparticles, average major axis 70 nm, major axis variation coefficient 6.7%, average major axis / average A copper oxide paste was prepared in the same manner as in Example 1 except that minor axis = 1.0 and average major axis / average middle diameter = 1.0 were used.

Screen printing was performed in the same manner as in Example 1 except that the obtained copper oxide paste was used, and evaluation was performed in the same manner. Further, conductorization treatment was performed in the same manner as in Example 1.
The obtained wiring had L / S = 190 μm / 10 μm and a wiring height of 2.8 μm. Moreover, the enlarged photograph of the pattern formed in FIG. 15 was shown. As shown in FIG. 15, the copper oxide particle-containing layer pattern was in partial contact with each other to form a short portion, resulting in poor printability.
Further, the surface resistance after the conductor treatment was 2.2 × 10 ⁻² Ω / □.

[Comparative Example 3]
In Example 1, instead of the copper oxide particles obtained in Production Example 1, plate-like copper oxide particles (manufactured by Chemilite, copper oxide nanoparticles, average major axis 1.7 μm, major axis variation coefficient 15.7%, average minor Example 1 except that 0.08 μm diameter, average major axis / average minor axis = 21.3, average middle diameter / average minor axis = 12.0, average major axis / average middle diameter = 1.8) A copper oxide paste was prepared.

Screen printing was performed in the same manner as in Example 1 except that the obtained copper oxide paste was used, and evaluation was performed in the same manner. Further, conductorization treatment was performed in the same manner as in Example 1.
The obtained wiring had L / S = 101 μm / 99 μm and a wiring height of 8.4 μm. Moreover, the enlarged photograph of the pattern formed in FIG. 16 was shown. As shown in FIG. 16, the copper oxide particle-containing layer pattern was in partial contact with each other to form a short portion, and the printability was poor.
Further, the surface resistance after the conductor treatment was 7.6 × 10 ⁻² Ω / □.

[Comparative Example 4]
In Example 1, instead of the copper oxide particles obtained in Production Example 1, spherical copper oxide particles (manufactured by Nakayama Gumi Co., Ltd., copper oxide nanoparticles, average major axis 215 nm, major axis variation coefficient 55.0%, average minor axis 196 nm Copper oxide in the same manner as in Example 1 except that average major diameter / average minor diameter = 1.1, average middle diameter / average minor diameter = 1.0, and average major diameter / average middle diameter = 1.1). A paste was prepared. Screen printing and conductorization treatment were performed in the same manner as in Example 1 except that the obtained copper oxide paste was used, and evaluation was performed in the same manner.

  From the above, it can be seen that a high-definition and low-resistance metal copper layer can be formed with high accuracy by using the copper oxide paste of the present invention.

DESCRIPTION OF SYMBOLS 1 Copper oxide particle 2 Length of major axis 3 Length of medium diameter 4 Length of minor axis

Claims (13)

  In the three-dimensional shape of the copper oxide particles, including a plurality of copper oxide particles, a parallel two-plane distance selected so as to maximize the distance between the parallel two planes out of the parallel two planes circumscribing the copper oxide particles The major axis is a minor axis of the distance between the two parallel planes selected to minimize the distance between the two parallel planes out of the two parallel planes orthogonal to the parallel two planes that give the major axis and circumscribing the copper oxide particles. In this case, for the plurality of copper oxide particles, the average value of the length of the major axis is 100 nm or more and less than 1700 nm, and the ratio of the average value of the length of the major axis to the average value of the length of the minor axis is 1. A copper oxide paste comprising a group of copper oxide particles of 2 to 20 and a dispersion medium.   The copper oxide particle group includes a parallel two-plane distance selected so that the distance between the parallel two planes is the largest among the two parallel planes that are orthogonal to the parallel two planes that give the major axis and circumscribe the copper oxide particles. When the medium diameter is set, the average value of the length of the major axis is 100 nm or more and less than 1700 nm for the plurality of copper oxide particles, and the average value of the length of the major axis with respect to the average value of the length of the minor axis The copper oxide paste according to claim 1, wherein the ratio is 1.2 or more and 20 or less, and the ratio of the average value of the length of the major axis to the average value of the length of the medium diameter is 2.0 or more.   The content rate of all the particles containing the said copper oxide particle group is 30 mass% or more and 80 mass% or less, and the content rate of the said copper oxide particle group in all the particles is 50 mass% or more. The copper oxide paste described in 1.   The copper oxide paste according to any one of claims 1 to 3, wherein the equilibrium viscosity of Casson measured by a viscoelasticity measuring device equipped with a cone plate is 0.01 Pa · s or more and 200 Pa · s or less. The copper oxide paste according to claim 1, wherein the dispersion medium includes an organic solvent having a vapor pressure at 25 ° C. of less than 1.34 × 10 ³ Pa · s.   It is an object for metal copper layer formation, The copper oxide paste of any one of Claims 1-5.   A step of forming the copper oxide particle-containing layer by applying the copper oxide paste according to any one of claims 1 to 6 on the support, and subjecting the copper oxide particle-containing layer to a conductor treatment The manufacturing method of a metal copper layer which has a process of forming a metal copper layer.   The manufacturing method according to claim 7, wherein the method of applying the copper oxide paste is a printing method.   The method according to claim 7 or 8, wherein the conductorization treatment is a method of heat-treating the copper oxide particle-containing layer in a formic acid-containing atmosphere.   The manufacturing method of any one of Claims 7-9 which further includes the process of carrying out the electrolytic plating process or the electroless-plating process to the formed said metal copper layer.   The conductor wiring containing the metal copper layer obtained with the manufacturing method of any one of Claims 7-10.   The electrode containing the metal copper layer obtained with the manufacturing method of any one of Claims 7-10.   The heat conduction path containing the metallic copper layer obtained with the manufacturing method of any one of Claims 7-10.