JP2009024191A - Dispersion of metallic nanoparticle and metallic coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material which is a dispersion of metallic nanoparticles having superior dispersibility and can form a thin and uniform metallic coating film having a low specific resistance value, particularly when formed by using the dispersion. <P>SOLUTION: The dispersion of the metallic nanoparticles includes the metallic nanoparticles with an average particle size of 1 to 100 nm, and at least one organic compound selected from ethers, ketones and esters (hereafter referred to as "organic compound X"). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an invention related to metal nanoparticles, a preferred method for producing the particles, a dispersion containing the particles, and a metal coating obtained from the dispersion.

  In recent years, inventions related to metal fine particles, in particular, technologies related to metals having a particle size of nano-size, have been proposed, and many literatures relating to methods for producing nanoparticles have been seen. For example, a method of obtaining fine particles by mixing an organic metal salt with a specific organic acid and then adding a reducing agent and subjecting it to a reduction treatment, stirring and mixing the metal salt and the organic medium in the presence of a phase transfer catalyst, And a method of introducing fine particle nuclei into the dispersion and newly depositing metal on the surface of the nuclei.

JP 2005-60816 JP 2004-183090 A JP 2004-51997 A

  With the above prior art methods, it is difficult to obtain nano-sized metal particles. In addition, when forming a metal film on a substrate, the nanoparticles may be applied to the substrate as a dispersion, but the specific resistance of the film tends to be high, and may be unsuitable for use as a wiring material or the like. There were many.

  The present invention contains a metal nanoparticle having an average particle diameter of 1 nm to 100 nm and at least one organic compound (organic compound X) selected from ethers, ketones and esters. Nanoparticle dispersion.

  The metal nanoparticle dispersion according to the present invention has good dispersibility, and when a metal film is formed using the dispersion, the metal film can be formed without increasing the specific resistance value which is one of the metal performances. Is.

  1st invention concerning this invention contains the metal nanoparticle whose average particle diameter is 1-100 nm, and at least 1 sort (s) of organic compound (organic compound X) chosen from ethers, ketones, and esters. A metal nanoparticle dispersion characterized by the following. The boiling point of the organic compound X is preferably 150 to 350 ° C. Moreover, it is preferable that at least one organic compound selected from the ethers, ketones and esters contains three or more oxygen atoms in one molecule. The dispersion preferably has a metal nanoparticle content of 10 to 80% by mass and an organic compound X content of 1 to 50% by mass. The metal of the metal nanoparticle is preferably silver and / or copper.

  2nd invention concerning this invention is a manufacturing method of the said metal nanoparticle dispersion | distribution characterized by disperse | distributing the metal nanoparticle whose average particle diameter is 1 nm-100 nm to the organic compound X. FIG.

  3rd invention concerning this invention is a metal film obtained by apply | coating a metal nanoparticle dispersion to a board | substrate, and baking at 100-600 degreeC.

  The metal nanoparticles according to the present invention have an average particle diameter of 1 nm to 100 nm, preferably 2 nm to 50 nm, more preferably 2 nm to 30 nm, and still more preferably 3 nm to 10 nm. Although the measurement method of the average particle diameter of a metal nanoparticle can be measured by the method used normally, Preferably a transmission electron microscope (TEM), a field emission transmission electron microscope (FE-TEM), a field emission scanning electron microscope (FE-). The particle diameter is measured by SEM) or the like, and the average value is obtained.

  The metal nanoparticles according to the present invention may be any metal, but are preferably aluminum, tungsten, nickel, gold, silver, copper, more preferably nickel, gold, silver, copper, Silver and / or copper are preferred. The metal nanoparticles include the metal (zero-valent) nanoparticles, nanoparticles made of the metal oxide, and mixtures thereof.

  In addition, the metal nanoparticle is preferably a metal (zero-valent) conductive material, and preferably has a specific resistance of 10 μΩ · cm or less when formed into a metal film. More preferably, it is 8 μΩ · cm or less.

  The metal nanoparticles according to the present invention may be produced by any production method as long as particles having an average particle diameter of 1 nm to 100 nm can be obtained, but preferably CVD method, gas evaporation method, spray pyrolysis It may be produced by any one of a method, a sol-gel method, a hydrothermal synthesis method, and a liquid phase reduction method. Most preferred is a liquid phase reduction method.

  The organic compound X according to the present invention has a boiling point of 150 to 350 ° C, preferably 200 to 300 ° C. The organic compound preferably has 3 or more oxygen atoms, and more preferably has 3 to 6 oxygen atoms. The most preferable one has a boiling point of 200 to 300 ° C. and 3 to 6 oxygen atoms.

  As ethers, ethyl butyl ether, butyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol n-propyl ether, anisole, propylene glycol n-butyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl ether, diethylene glycol monoethyl Ether, dipropylene glycol n-propyl ether, dihexyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, propylene glycol phenyl ether, tripropylene glycol n-butyl ether, diethylene glycol monobutyl ether, diphenyl ether, preferably anisole, The Pyrene glycol n-butyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl ether, diethylene glycol monoethyl ether, dipropylene glycol n-propyl ether, dihexyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, propylene glycol phenyl ether , Tripropylene glycol n-butyl ether, diethylene glycol monobutyl ether, diphenyl ether, more preferably diethylene glycol monoethyl ether, dipropylene glycol n-propyl ether, dihexyl ether, dipropylene glycol n-butyl ether, tripropylene glycol methyl ether, propylene glycol Ruphenyl ether, tripropylene glycol n-butyl ether, diethylene glycol monobutyl ether, diphenyl ether, and the ketones are diethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, methyl phenyl ketone, isophorone, preferably cyclohexanone, methyl Preferred are phenyl ketone and isophorone, and more preferred are methyl phenyl ketone and isophorone. Examples of esters include ethyl acrylate, isobutyl formate, n-propyl acetate, ethyl propionate, methyl butyrate, butyl acetate, isobutyl acetate, and ethyl butyrate. , Ethyl isobutyrate, propyl propionate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, ethylene acetate Glycol monoethyl ether, 3-methoxybutyl acetate, cyclohexanol acetate, ethylene glycol monobutyl ether, propylene glycol diacetate, methyl benzoate, ethyl benzoate, dipropylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, 1,3 -Butylene glycol diacetate, diethylene glycol monobutyl ether acetate, butyl benzoate, triacetin, dibutyl phthalate, preferably ethylene glycol monoethyl ether acetate, 3-methoxybutyl acetate, cyclohexanol acetate, ethylene glycol monobutyl ether, propylene glycol Diacetate, methyl benzoate, ethyl benzoate, dipropylene glycol methyl ether acetate, diacetate Tylene glycol monoethyl ether, 1,3-butylene glycol diacetate, diethylene glycol monobutyl ether acetate, butyl benzoate, triacetin, dibutyl phthalate, more preferably ethyl benzoate, dipropylene glycol methyl ether acetate, diethylene glycol monoethyl acetate Ether, 1,3-butylene glycol diacetate, diethylene glycol monobutyl ether acetate, butyl benzoate, and triacetin, more preferably dipropylene glycol methyl ether acetate, diethylene glycol monoethyl ether acetate, 1,3-butylene glycol diacetate, acetic acid Diethylene glycol monobutyl ether and triacetin. Of ethers, ketones and esters, esters are preferred.

  The metal nanoparticle dispersion according to the present invention contains at least metal nanoparticles and the organic compound. The metal nanoparticles are contained in an amount of 10 to 80% by mass, preferably 15 to 70% by mass, more preferably 20 to 60% by mass, while the organic compound is 1 to 50% by mass with respect to the metal nanoparticle dispersion. It is contained by mass%, preferably 2-40 mass%, more preferably 3-30 mass%. When the dispersion is formed only from the metal nanoparticles and the organic compound, the total amount is 100% by mass. Other components (additional components) can also be added, such as aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, metal alkoxides, aldehydes, organic acids, organic acid salts, thiols, amines, preferably aliphatic carbonizations. Hydrogen and aromatic hydrocarbons. The amount of the additive component is such that the amount including the metal nanoparticles and the organic substance is 100% by mass.

  The viscosity of the dispersion may be appropriately selected according to the method of applying the dispersion, but is 50 mPa · s or less when the dispersion is applied only to a necessary portion on the substrate using an inkjet head. Those are preferred.

  The dispersion can be used for any application as long as it requires metal fine particles. For example, the dispersion is preferably used for forming a metal film and particularly for forming a thin film. The metal thin film is formed by applying the dispersion to a substrate and firing at 100 ° C. to 600 ° C., preferably 100 ° C. to 450 ° C., more preferably 100 ° C. to 350 ° C.

  The coating can be used for wiring, electrodes, conductive films, semiconductor films, and the like.

  A preferable example of the production method of nanoparticle dispersion from nanoparticle production is as follows. A reducing agent is added by adding a reducing agent to a solution containing a first organic acid metal salt and an amine compound in an inert gas atmosphere. (Reduction treatment), a solution containing the second organic acid metal salt and the amine compound is added to the solution and reduction treatment (second reduction treatment) is performed to obtain metal nanoparticles having an average particle diameter of 1 nm to 100 nm. (Particle manufacturing process). Subsequently, after adding a washing | cleaning liquid, it filters and isolate | separates a deposit, Furthermore, an organic solvent is added and melt | dissolved in the said deposit (re-dissolution process). Furthermore, a part or all of the organic solvent is removed by distillation or the like, and the organic compound X is added to the precipitate (organic compound X addition step) to obtain a metal nanoparticle dispersion.

  The present invention will be described in more detail with reference to examples and comparative examples, but is not limited to the following examples unless it is contrary to the spirit of the present invention.

Example 1
A 3 L separable flask was charged with 94.3 g of copper acetate monohydrate (manufactured by Wako Pure Chemical Industries, Ltd.) and 610.2 g of octylamine (manufactured by Wako Pure Chemical Industries, Ltd.), and stirred and mixed at 40 ° C. for 20 minutes. did. Next, 1.5 L / min. Was held for 30 minutes while bubbling, and the inside of the separable flask was brought to an inert gas atmosphere. Subsequently, 1.5 L / min. In a state where the supply of nitrogen gas was maintained, 221.0 g of a 10% by mass dimethylamine borane-acetone solution was gradually added to the separable flask to reduce the copper. Subsequently, silver is reduced by gradually adding a solution prepared by dissolving 46.4 g of silver acetate (manufactured by Kishida Chemical Co., Ltd.) in 359.4 g of octylamine (manufactured by Wako Pure Chemical Industries, Ltd.) into the separable flask. Processing was carried out. Although the liquid temperature rose during the reduction treatment of copper and silver, the liquid temperature never exceeded 55 ° C.

  After the solution after the reduction treatment was transferred to a 15 L SUS container, 8 L of acetone was added and allowed to stand for a while, and then a precipitate composed of copper, silver and organic matter was separated by filtration. Hexane was added to the separated precipitate to redissolve it, cooled to 10 ° C. or lower, and filtered using a membrane filter having a pore size of 0.1 μm. Subsequently, hexane is removed from the filtrate under reduced pressure, and then an appropriate amount of tetradecane (manufactured by Wako Pure Chemical Industries, Ltd.) and anisole (Wako Pure Chemical Industries, Ltd.) are added and mixed with stirring to form a metal composed of copper and silver. A dispersion (1) containing 50% by mass of nanoparticles and 15% by mass of anisole was obtained.

  When the dispersion (1) was observed with an FE-SEM, the average particle diameter of the metal nanoparticles was 4 nm. Moreover, when analyzed using ICP, the mass ratio (Cu / Ag) of copper and silver was 25/75.

(Examples 2 to 6)
Dispersions (2) to (6) were obtained in the same manner as in Example 1, except that isophorone, ethyl benzoate, butyl benzoate, dibutyl phthalate, and diethylene glycol monobutyl ether acetate were added instead of anisole in Example 1. It was. In each dispersion, the content of metal nanoparticles composed of copper and silver is 50% by mass, and the content of at least one organic compound selected from ethers, ketones and esters is 15% by mass. there were.

(Comparative Example 1)
A dispersion (Comparative 1) containing 50% by mass of metal nanoparticles composed of copper and silver was obtained in the same manner as in Example 1 except that no anisole was added in Example 1.

(Example 7)
The metal nanoparticle dispersions (1) to (6) and (Comparative 1) obtained in Examples 1 to 6 and Comparative Example 1 were each applied to a spin coater on a glass substrate having an area of 2.5 cm × 3.5 cm. After application, the glass substrate was placed in a firing furnace. The temperature was raised from room temperature to 250 ° C. in 0.5 hours while circulating 4% by volume of hydrogen (the remaining 95% by volume of nitrogen) in the firing furnace. After the temperature reached 250 ° C., the metal film was obtained by holding for 0.5 hour and firing in a reducing atmosphere. The thickness of each metal coating was 0.5 μm. Subsequently, the specific resistance value of the obtained metal coating was measured using a low resistivity meter (Loresta GP, manufactured by Mitsubishi Chemical Corporation). The results are shown in Table 1.

  The present invention is a metal nanoparticle dispersion, which is excellent in dispersibility, and in particular, when a metal film is formed using the dispersion, a uniform metal film can be obtained with a thin film. For example, it can be used as a wiring material, and the metal film having a low specific resistance can be obtained.

Claims (7)

It contains metal nanoparticles having an average particle diameter of 1 nm to 100 nm and at least one organic compound selected from ethers, ketones and esters (hereinafter also referred to as “organic compound X”). Metal nanoparticle dispersion. The metal nanoparticle dispersion according to claim 1, wherein the boiling point of at least one organic compound selected from ethers, ketones and esters is 150 to 350 ° C. The metal nanoparticle dispersion according to claim 1 or 2, wherein at least one organic compound selected from ethers, ketones and esters contains 3 or more oxygen atoms in one molecule. The metal nanoparticle content is 10 to 80% by mass, and the content of at least one organic compound selected from ethers, ketones and esters is 1 to 50% by mass. The metal nanoparticle dispersion according to 1 to 3. The metal nanoparticle dispersion according to claim 1, wherein the metal of the metal nanoparticles is silver and / or copper. 2. The method for producing a metal nanoparticle dispersion according to claim 1, wherein metal nanoparticles having an average particle diameter of 1 nm to 100 nm are dispersed in the organic compound X. 3. A metal film obtained by applying the metal nanoparticle dispersion according to any one of claims 1 to 5 to a substrate and then firing at 100 to 600 ° C.