JP5849641B2 - Method for producing copper oxide particles - Google Patents

Description

The present invention relates to a method for producing a copper oxide particle element group.

  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 copper particles, 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).
Also disclosed is a method of producing plate-like copper particles by adding an alkali agent to an aqueous copper salt solution to precipitate copper hydroxide and reducing it (see, for example, Patent Document 2).

International Publication No. 2011/0334016 Pamphlet JP-A-11-350009

In forming a copper metal pattern using copper oxide particles, copper oxide particles having excellent dispersibility in a dispersion medium and a method for producing the same are required.
The present invention aims to provide a method for producing a copper oxide particle element group which is excellent in dispersibility.

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 parallel two 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 shortened. The diameter of the parallel two planes orthogonal to the parallel two planes giving the major axis and circumscribing the copper oxide particles is selected to be the distance between the two parallel planes selected to maximize the distance between the parallel two planes. 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 600 nm 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 minor axis is 2.9. It is 5.5 or less and the medium diameter The ratio of the average value of the length of the major axis to the average value of the length of the copper oxide particles is 2.0 or more, and the pH is 6.0 or more and 8.5 or less containing copper hydroxide and alcohol. It is a manufacturing method of the copper oxide particle group which has the process of heat-processing a hydrous composition and producing | generating a copper oxide .

<2> The method for producing a copper oxide particle group according to <1>, wherein the carbon atom content in the copper oxide particle group is 2% by mass or less.

< 3 > The method for producing a copper oxide particle group according to < 1 > or <2> , wherein the temperature of the heat treatment is 60 ° C. or higher and 100 ° C. or lower.

The manufacturing method of the copper oxide particle group of any one of said < 1 > -<3> which further has the process of adding a basic compound and alcohol to the aqueous solution of < 4 > copper complex, and obtaining the said water-containing composition. It is.

< 5 > The said copper complex is a manufacturing method of the copper oxide particle group as described in said < 4 > which is a water-soluble copper complex which consists of a bivalent copper ion and a ligand.

< 6 > The production of the copper oxide particle group according to any one of < 1 > to < 5 >, further including a cleaning step of removing at least a part of the ionic compound after the step of generating the copper oxide. Is the method.

< 7 > The production of the copper oxide particle group according to < 6 >, wherein the washing step includes at least one washing treatment selected from the group consisting of ultrafiltration, microfiltration, centrifugation, dialysis, and pure water washing. Is the method.

According to the present invention, it is possible to provide a manufacturing method of the copper oxide particles element group which is excellent in dispersibility.

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

  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. Furthermore, in this specification, the amount of each component in the composition is the total amount of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. means.

<Copper oxide particles>
The copper oxide particle group of the present invention includes a plurality of copper oxide particles, and in the three-dimensional shape of the copper oxide particles, among the parallel two planes circumscribing the copper oxide particles, the parallel two planes whose distance is maximum The distance between the two parallel planes perpendicular to the parallel two planes giving the major axis and circumscribing the copper oxide particles is defined as the short axis, and the parallel axis giving the major axis is the shortest distance. Of the parallel two planes orthogonal to the two planes and circumscribing the copper oxide particles, the length of the major axis of the plurality of copper oxide particles when the distance between the parallel two planes having the maximum distance is the medium diameter The average value of the major axis (hereinafter also referred to as “average major axis”) is 100 nm or more and 600 nm or less, and the average value of the major axis length relative to the average value of the minor axis length (hereinafter also referred to as “average minor axis”) The ratio of 2.9 to 5.5 , The average value of the length of said in diameter (hereinafter, also referred to as "average in size") ratio of the average length of the major axis relative to is 2.0 or more.

  The copper oxide particle group is composed of copper oxide particles having a specific shape, and the long diameter, medium diameter and short diameter satisfy a specific relationship, so that the dispersibility in the dispersion medium is excellent. The paste composition formed by using it exhibits excellent screen printability. Therefore, as will be described later, when this is used to form a copper oxide paste and applied to a method for producing a conductor pattern, a high-definition and low-resistance conductor pattern can be formed.

  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 at a magnification of 20,000, for example. The observation is performed under the condition that the observed copper oxide particles can be identified as independent particles.

  The shape of the copper oxide particles is defined by an average value of the lengths of the long diameter, the medium diameter, and the short 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 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. On the other hand, when the shape of the copper oxide particles is in the form of a lump or ribbon, the variation in the size of the individual copper oxide particles becomes too large (for example, because the coefficient of variation exceeds 20%), which is a meaningful average value. Cannot be obtained. The coefficient of variation is obtained by dividing the standard deviation by the average 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. . The observation with a scanning electron microscope is performed at 20,000 times (acceleration voltage 5 kV). Further, the observation is performed under the condition that each observed copper oxide particle can be identified as an independent particle.

  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. Of the parallel two planes circumscribing the copper oxide particles 1 schematically shown in FIG. 1, the first parallel two planes having the maximum distance between the parallel two planes are selected, and oxidation is performed as the distance between the first parallel two 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 a major axis of 100 nm or more and 600 nm or less, but from the viewpoint of dispersibility and the fineness of the formed conductor pattern, the thickness is 110 nm or more and 550 nm or less. It is preferable that it is 120 nm or more and 500 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 600 nm, the printability of the copper oxide paste tends to be lowered, and the copper oxide particle group production method described later further decreases. It becomes difficult to synthesize.

  A preferable shape of the copper oxide particles constituting the copper oxide particle group is not a substantially spherical shape, a plate shape, or a needle shape, which is a general shape as the copper oxide particles, but a long granular particle. Here, the term “long granular” means that the ratio of the average major axis to the average minor axis (average major axis / average minor axis) is 2.9 to 5.5, and the ratio of the average major axis to the average middle diameter (average major axis / average middle diameter). ) Is 2.0 or more. (Average major axis value) / (average minor axis) is a so-called aspect ratio. The closer the value is to less than 2.9 and to 1, the closer to a spherical shape. Moreover, the case where the value is 2.9 or more and 5.5 or less is defined as a long granular or scaly particle shape. Furthermore, the case of exceeding 5.5 is defined as a needle-like or plate-like particle shape. Further, (average major axis) / (average median diameter) is {(average major axis) / (average minor axis)} / {(average median diameter) / (average minor axis)}, and the value is 2.0 or more. A certain case is defined as a long granular or acicular particle shape. On the other hand, the case of less than 2.0 is defined as a scale or plate.

  The shape of the copper oxide particle group will be described with reference to FIG. In FIG. 2, the ratio of the average major axis to the average minor axis (average major axis / average minor axis) is taken on the horizontal axis, and the ratio of the average medium diameter to the average minor axis (average medium diameter / average minor axis) is taken on the vertical axis. It is a figure which shows typically the shape distribution of the copper oxide particle in. In FIG. 2, 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, as the average major axis / average minor axis becomes a constant value (for example, 2.9 or more and 5.5 or less), the particle shape increases as the average medium diameter / average minor axis becomes larger than 1. And plate-like. In addition, the average major axis / average minor axis, the average middle diameter / average minor axis, and the average major axis / average minor axis are all 1 or more in terms of the definition of major axis, middle axis and minor axis.

  The copper oxide particle group of the present invention has an average major axis / average minor axis of 2.9 to 5.5 and an average major axis / average median of 2.0 or more. Therefore, the copper oxide particle group of the present invention has a straight line having an average major axis / average minor axis of 2.9 orthogonal to the horizontal axis and an average major axis / average minor axis of 5.5 perpendicular to the horizontal axis in FIG. It passes through a straight line, a straight line perpendicular to the vertical axis and having an average medium diameter / average minor axis of 1, an average major axis / average minor axis of 2 and an average medium diameter / average minor axis of 1, and a slope ( It belongs to a region surrounded by a straight line having an average medium diameter / average short diameter) / (average long diameter / average short diameter) of 1/2.

  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 plate-like, scale-like or needle-like, the interaction due to the increase in the contact area between the particles becomes stronger, the particle concentration decreases due to the increase in viscosity, or the thixotropy becomes too large. Therefore, the screen printability tends to decrease.

  In the copper oxide particle group, the average major axis / average minor axis is 2.9 or more and 5.5 or less, but the average major axis / average minor axis is from the viewpoint of dispersibility and printability when a copper oxide paste is constituted. It is preferable that it is 2.9 or more and 5.0 or less. Moreover, in the said copper oxide particle group, although average long diameter / average medium diameter is 2.0 or more, from a viewpoint of the printability at the time of comprising dispersibility and a copper oxide paste, average long diameter / average medium diameter is 2.5. The above is preferable.

  Further, the copper oxide particle group has an average major axis of 110 nm to 550 nm and an average major axis / average minor axis of 2.9 to 5.5 from the viewpoints of dispersibility and printability when a copper oxide paste is formed. The average major axis / average median diameter is preferably 2.0 or more, the average major axis is 120 nm or more and 500 nm or less, the average major axis / average minor axis is 2.9 or more and 5.0 or less, and the average major axis is / The average median diameter is more preferably 2.5 or more.

  Examples of the copper oxide constituting the copper oxide particles 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.

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 the copper oxide particles constituting the copper oxide particle group are treated with a surface treatment agent or a raw material organic copper complex. It means that organic compounds such as, dispersibility and oxidation resistance are not substantially contained. 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.
In addition, the content rate of the carbon atom contained in a copper oxide particle group is measured by the combustion gas infrared absorption method. Specifically, for example, the measurement is performed under normal conditions using an EMIA-V series manufactured by Horiba, Ltd.

<Method for producing copper oxide particles>
The manufacturing method of the copper oxide particle group of this invention has the process of heat-processing the water-containing composition of pH 6 or more and 8.5 or less containing copper hydroxide, and produces | generates copper oxide, and other processes as needed. It is comprised including.
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.

Although the pH of the water-containing composition in the production method is 6 or more and 8.5 or less, from the viewpoint of efficiently obtaining copper oxide particles having a desired aspect ratio, it is preferably 6.5 or more and 8.3 or less, More preferably, it is 7.0 or more and 8.0 or less.
In general, when a water-containing composition containing copper hydroxide is heat-treated under conditions of pH 8.7 or higher, plate-like copper oxide particles are produced, but it has a desired aspect ratio by being heat-treated at pH 6 or higher and 8.5 or lower. Long granular copper oxide particles can be obtained.

  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 or more and 8.5 or less, and even an organic acid copper complex having an organic acid base as a ligand may be an inorganic acid base. An inorganic copper complex having a ligand as a ligand may be used.
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 forming 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 made smaller. 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. Ionic impurities reduce the electrostatic repulsion between particles in the dispersion and lower the dispersibility and dispersion stability. When a copper oxide paste is constituted by the washing step, a copper oxide paste that is stable at a higher concentration can be prepared.

  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 stability of the 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, and 1000 mS / m It is more preferable to carry out so as to be m or less.

Since the copper oxide particle group is composed of copper oxide particles having a specific shape, the copper oxide particle group is excellent in dispersibility in a dispersion medium and is suitably applied to the preparation of a copper oxide paste for forming a conductor pattern. By using it as a copper oxide paste for forming a conductor pattern, a conductor pattern with high definition and low resistance can be formed. Further, the formed conductor pattern has a dense crystal structure, and has a low volume resistivity and a high thermal conductivity. For the copper oxide paste and a method of forming a conductor pattern using the same, for example, International Publication No. 2011/034016 pamphlet can be referred to.
In addition, the copper oxide particle group has a substantially spherical shape, which is a general shape as conventional copper oxide particles, and has a long granular shape different from a plate shape, and is excellent in dispersion stability with respect to the medium. In addition to the forming copper oxide paste, the present invention can be applied to colored paints, antibacterial paints, and heat radiation pattern formation.

(Copper oxide paste)
The copper oxide paste for forming a conductor pattern includes, for example, at least one kind of the copper oxide particle group (hereinafter, also simply referred to as “copper oxide particles”) and a dispersion medium, and includes other components as necessary. Composed. The copper oxide paste containing the copper oxide particles can form a high-definition and low-resistance conductor pattern. This can be considered as follows, for example.
In the formation of a conductor pattern using copper oxide paste, the physical properties of the copper oxide paste include the formability of the pattern containing copper oxide particles and the stability of the pattern shape when it is heat-treated in a reducing atmosphere to form a conductor. 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 particles have a specific shape and high affinity with the dispersion medium, the copper oxide paste including the copper oxide particles does not adjust the physical properties by the dispersant or additive. However, it exhibits physical properties excellent in pattern formation and shape stability. Therefore, it can be considered that a conductor pattern having high conductivity can be formed in the conductor treatment.

  The content rate of the copper oxide particles in the copper oxide paste can be appropriately selected according to the method of applying the copper oxide paste. For example, it can be 1 mass%-95 mass%, and it is more preferable that it is 20 mass%-80 mass%.

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 contain other copper-based particles as necessary in addition to the copper oxide particles. Examples of other copper-based particles include copper oxide particles having a shape other than the copper oxide particles, metal copper particles, and the like. By further including other copper-based particles, it is possible to improve applicability such as printability, storage stability, conductorization characteristics, conductor layer characteristics, and the like. For example, the application suitability can be adjusted by adding small-sized copper-based particles or spherical copper-based particles. Moreover, storage stability improves by adding a chestnut-like copper-type particle | grain. Moreover, the conductor-treatment temperature can be lowered by adding metallic copper particles. Furthermore, the densification of the conductor layer formed by adding small copper particle can be promoted.

  The content of other copper-based particles is not particularly limited as long as it does not impair the pattern formability obtained by the copper oxide particle group. For example, it can be 30 volume% or less with respect to the said copper oxide particle.

  The copper oxide paste may further include other metal-based particles in addition to the copper oxide particles and other copper-based particles included as necessary. Examples of other metal-based particles include particles containing cobalt, nickel, silver, gold, molybdenum, manganese, magnesium, iron, and oxides thereof.

The particle shape of the other metal-based particles 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 other metal particles 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 conductor layer. The particle diameter of other metal particles can be measured by observation using a scanning electron microscope.

  The content of other metal-based particles is not particularly limited as long as it does not impair the pattern formability obtained with the copper oxide particle group. For example, it can be 10 volume% or less with respect to the said copper oxide particle.

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 conductor 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 conductor 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 an inkjet 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.

  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.

  The copper oxide paste can be prepared, for example, by dispersing the copper oxide particle group and other copper-based particles and other metal-based particles contained 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, 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.

[Conductor pattern manufacturing method]
The conductor pattern manufacturing method using the copper oxide paste includes, for example, a step of forming a copper oxide particle-containing layer by applying a copper oxide paste on an insulating layer, and the presence of formic acid gas in the formed copper oxide particle-containing layer. And a conductor treatment process for reducing copper oxide to metallic copper by heat treatment below, and having other processes 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 insulating layer for forming the conductor pattern is not particularly limited, and can be appropriately selected from generally used insulating layers 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 insulating layer is used, a flexible and lightweight device can be configured.

  The method of applying the copper oxide paste on the insulating layer and patterning the copper oxide particle-containing layer 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 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 heat-treated in the presence of formic acid gas to reduce the copper oxide to metallic copper to form a conductor pattern. By using formic acid gas, a dense metal copper film is generated, and a conductor pattern having a low volume resistivity and high thermal conductivity can be formed.

  The concentration of formic acid gas 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. Moreover, other gas components other than formic acid gas may be contained. 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 in which nitrogen gas is circulated in liquid formic acid and nitrogen gas containing formic acid gas is provided to the object to be processed. Can be provided.

  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 rate. The upper limit of the processing temperature is defined by the heat resistance temperature of an insulating layer (for example, a substrate) that forms the conductor pattern. Further, the treatment pressure may be any of atmospheric pressure, reduced pressure, and increased pressure without particular limitation.

Since the conductor pattern containing metallic copper 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.
The conductor pattern thus formed can also be used as a seed layer for electroless plating or an ultrathin copper layer for electrolytic plating when forming a thick fine wiring.

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. Moreover, all of Example 1 and Examples 4-9 shall be read as a reference example.

[Example 1]
(Synthesis of copper oxide particles)
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 with the personal pH sensor pH72-21JAA made from Yokogawa Electric.
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 1.0g (65% yield)

  As a result of observation of the copper oxide particle group by a scanning electron microscope (SEM), as shown in FIG. 3, the particles were long granular particles having an average major axis of 400 nm, an average medium diameter of 110 nm, and an average minor axis of 110 nm. The average major axis, average median diameter, and average minor axis were measured for 20 arbitrarily selected copper oxide particles and calculated as the arithmetic average thereof. The average major axis / average minor axis was 3.6, and the average major axis / average median diameter was 3.6. The major axis variation coefficient 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. 5, 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.

[Example 2]
(Synthesis of copper oxide particles)
In Example 1, copper oxide particles were synthesized in the same manner as in 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, they were oval particles having an average major axis of 150 nm and an average minor axis of 30 nm, and the diameter was reduced as compared with the copper oxide particle group obtained in Example 1. The average major axis / average minor axis was 5.0, and the average major axis / average median diameter was 5.0.

As a result of XRD measurement, as shown in FIG. 5, 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.

[Example 3]
In Example 1, copper oxide particles were synthesized in the same manner as in 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 oval particles having an average major axis of 120 nm and an average minor axis of 30 nm, and the diameter was reduced as compared with the copper oxide particle group obtained in Example 1. The average major axis / average minor axis was 4.0, and the average major axis / average median diameter was 4.0.

As a result of XRD measurement, as shown in FIG. 5, 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

[Examples 4 to 6]
In Example 1, the addition amount of anhydrous copper acetate (II) was 5.0 g (0.033 mol / kg), 6.8 g (0.045 mol / kg), and 13.6 g (0.090 mol / kg), respectively. Copper oxide particles were synthesized in the same manner except that.
As a result, a group of copper oxide particles having substantially the same particle size and particle shape was obtained regardless of the raw material copper ion concentration 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 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.

[Comparative Example 1]
In Example 1, copper oxide particles were synthesized in the same manner except that 184 g of the pH adjusting agent 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 observation of the copper oxide particles by SEM, 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, and the average major axis / average median diameter was 2.9.

[Examples 7 to 9, Comparative Examples 2 to 4]
In Example 1, 3.4 g of anhydrous copper acetate (II) was dissolved in 170 g of pure water. The copper oxide particles were synthesized in the same manner except that the pH adjusting agent was added to the predetermined pH shown in the table below while measuring the pH, and the copper ion 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. 8 shows the copper oxide particle group obtained in Example 7. 9 and 10 show the copper oxide particle group obtained in Example 8. FIG. 11 and 12 show the copper oxide particle group obtained in Example 9. FIG. FIG. 13 shows the copper oxide particle group obtained in Comparative Example 2. 14 and 15 show the copper oxide particle group obtained in Comparative Example 3. FIG. 16 and 17 show the copper oxide particle group obtained in Comparative Example 4. FIG.

  Further, in Comparative Example 2 where the pH at the time of synthesis was 5.5, massive copper oxide particles were generated, and it was difficult to measure the short diameter and medium diameter of each particle. In Comparative Example 3 where the pH at the time of synthesis was 9.4, scaly copper oxide particles were generated. In Comparative Example 4 where the pH during synthesis was 11.6, ribbon-like copper oxide particles were produced.

[Evaluation 1]
A copper oxide paste using the copper oxide particles obtained above was prepared, and the printability serving as a dispersibility index was evaluated as follows. The evaluation results are shown in Table 1.
(Preparation of copper oxide paste)
25 g of the copper oxide particles obtained in Example 1 were weighed in a plastic container, and 25 g of terpineol was added so that the solid content was 50% by volume 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, coarse particles were 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.

(Screen printing)
Using a nylon mesh printing plate (L / S = 100 μm / 100 μm) and a hand-printed screen printing machine on a PEN film (polyethylene naphthalate film, film thickness 50 μm), the prepared copper oxide paste is applied for pattern printing. 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, bleeding occurred and the line was short-circuited.
C: L / S = 100 μm / 100 μm When printing on a printing plate, scraping occurred and the line was broken.
D: A large amount of coarse particles remained on the mesh when passing through a nylon mesh (aperture 100 μm).

It can be seen that the copper oxide paste prepared using the copper oxide particles of the present invention has good dispersibility and excellent screen printability.
On the other hand, when the copper oxide particle group obtained in Comparative Example 2 was used, the affinity with the dispersion medium was poor and separation from the dispersion medium occurred. Moreover, when the copper oxide particle group obtained in Comparative Example 1 and Comparative Example 4 was used, coarse particles were generated because of poor dispersibility, and a large amount of coarse particles remained in the nylon mesh (aperture 100 μm). In the copper oxide paste prepared using the copper oxide particle group obtained in Comparative Example 3, fading occurred during screen printing, and the printability was poor.
From the above, it can be judged that the copper oxide particles synthesized at pH 6.0 to 8.5 can be applied as a raw material for copper oxide paste. Moreover, it can be judged that long granular particles having a ratio of the average major axis to the average minor axis of 2.9 or more and 5.5 or less and a ratio of the average major axis to the average medium diameter of 2.0 or more are suitable.

[Evaluation 2]
(Screen printing and conductorization)
Using the copper oxide paste prepared using the copper oxide particle group obtained in Example 1, pattern formation of the copper oxide particle-containing layer was performed in the same manner as described above. Specifically, it is as follows. The prepared copper oxide paste was applied onto a PEN film (polyethylene naphthalate film, film thickness 50 μm) using a nylon mesh printing plate (L / S = 100 μm / 100 μm) and a hand-printed screen printer. A test piece on which a pattern containing copper oxide was formed by drying on a hot plate at 180 ° C. for 15 minutes was obtained. The formed pattern had L / S = 165 μm / 45 μm and a wiring height of 3.0 μm. Moreover, the enlarged photograph of the pattern formed in FIG. 18 was shown.

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 volume resistivity of the obtained conductor layer was 2.1 × 10 ⁻⁷ Ω · m. Moreover, when this was subjected to FIB cross-section processing and SIM observation, the average film thickness was 690 nm. FIG. 19 shows a SIM photograph.

  From the above, it can be seen that the copper oxide particle group of the present invention is excellent in dispersibility in a dispersion medium, and has excellent printability and excellent pattern formability when a copper oxide paste is constituted.

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

Claims (7)

Containing a plurality of copper oxide particles,
In the three-dimensional shape of the copper oxide particles, among the parallel two planes circumscribing the copper oxide particles, the distance between the parallel two planes selected so as to maximize the distance between the parallel two planes is the major axis,
Among the parallel two planes orthogonal to the parallel two planes that give the major axis and circumscribing the copper oxide particles, the distance between the parallel two planes selected to minimize the distance between the parallel two planes is the minor axis,
Among the parallel two planes orthogonal to the parallel two planes that give the major axis and circumscribing the copper oxide particles, when the distance between the parallel two planes selected so as to maximize the distance between the parallel two planes,
For the plurality of copper oxide particles, the average value of the length of the major axis is 100 nm or more and 600 nm 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 minor axis is 2.9 or more and 5 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, and is a method for producing a copper oxide particle group having a ratio of 2.0 or more ,
The manufacturing method of the copper oxide particle group which has the process of heat-processing the water-containing composition of pH 6.0-8.5 containing copper hydroxide and alcohol, and producing | generating a copper oxide . The manufacturing method of the copper oxide particle group of Claim 1 whose content rate of the carbon atom in the said copper oxide particle group is 2 mass% or less. The manufacturing method of the copper oxide particle group of Claim 1 or Claim 2 whose temperature of the said heat processing is 60 degreeC or more and 100 degrees C or less. The manufacturing method of the copper oxide particle group of any one of Claims 1-3 which further has the process of adding a basic compound and alcohol to the aqueous solution of a copper complex, and obtaining the said water-containing composition. The said copper complex is a water-soluble copper complex which consists of a bivalent copper ion and a ligand, The manufacturing method of the copper oxide particle group of Claim 4 . Wherein after the step of generating copper oxide, at least part manufacturing method of the copper oxide particles according to any one of claims 1 to 5 in which the cleaning step further comprising the removal of ionic compounds. The said washing | cleaning process is a manufacturing method of the copper oxide particle group of Claim 6 including the at least 1 sort (s) of washing process chosen from the group which consists of ultrafiltration, microfiltration, centrifugation, dialysis, and a pure water washing | cleaning.