JP2006210197A - Metal coating film and its formation method - Google Patents

Metal coating film and its formation method Download PDF

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JP2006210197A
JP2006210197A JP2005022097A JP2005022097A JP2006210197A JP 2006210197 A JP2006210197 A JP 2006210197A JP 2005022097 A JP2005022097 A JP 2005022097A JP 2005022097 A JP2005022097 A JP 2005022097A JP 2006210197 A JP2006210197 A JP 2006210197A
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JP4761110B2 (en
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Kazumasa Okada
一誠 岡田
Kohei Shimoda
浩平 下田
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Sumitomo Electric Industries Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a dense metal coating film formed by sintering multiple metal particulate and excelling in adhesiveness to a base material; and to provide its formation method. <P>SOLUTION: This metal coating film is formed by heat-treatment of a coating film formed by printing or applying and drying a metal particulate dispersion liquid containing, along with a disperser containing carbon atoms, metal particulate comprising an alloy or a complex of a metal element and at least one kind of oxidizing metal element having an oxidizing property higher than that of the metal element. The content of carbon atoms included in the metal coating film is not greater than 1 wt.%, and the content of the oxide of the oxidizing metal element in the total amount of the oxidizing metal element included in the metal coating film is not greater than 5 wt.%. In this formation method, the coating film is first heat-treated in an oxidizing atmosphere and thereafter heat-treated in a reducing atmosphere again. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、多数の微細な金属微粒子を焼結させて形成され、導体回路等として使用される金属被膜と、その形成方法とに関するものである。   The present invention relates to a metal film formed by sintering a large number of fine metal particles and used as a conductor circuit, and a method for forming the metal film.

エレクトロニクス分野において、回路基板を製造するため、基板表面に導体回路等の金属被膜をパターン形成する方法として、従来は、フォトリソグラフ法によってパターン形成したレジスト膜を利用した形成方法が一般的に用いられてきた。しかし、この形成方法では、フォトリソグラフ法によるレジスト膜の形成に要する工程数が極めて多く、製造作業に手間がかかること等から、回路基板の生産性が低くなり、製造コストが高くつくという問題があった。   In the field of electronics, in order to manufacture a circuit board, conventionally, a formation method using a resist film patterned by a photolithographic method is generally used as a method of patterning a metal film such as a conductor circuit on the surface of the substrate. I came. However, in this forming method, the number of steps required for forming a resist film by the photolithographic method is extremely large, and the manufacturing work is troublesome. Therefore, there is a problem that the productivity of the circuit board is lowered and the manufacturing cost is increased. there were.

そこで、平均粒径がナノメーターレベルという微細な金属微粒子を、その表面を被覆して、当該金属微粒子の室温付近での融着と、それによる疎な凝集体の形成とを防止する機能を有する有機系の分散剤と共に、分散媒中に分散して金属微粒子分散液を調製し、この金属微粒子分散液を、基材表面に印刷または塗布し、乾燥させて塗膜を形成した後、250以下の温度で熱処理して金属被膜を形成することが提案された(例えば、特許文献1参照)。   Therefore, the surface of fine metal fine particles having an average particle diameter of nanometer level is coated, and the metal fine particles have a function of preventing fusion of the metal fine particles near room temperature and thereby forming sparse aggregates. After being dispersed in a dispersion medium together with an organic dispersant to prepare a metal fine particle dispersion, this metal fine particle dispersion is printed or coated on the surface of the substrate and dried to form a coating film. It has been proposed to form a metal film by heat treatment at a temperature of (see, for example, Patent Document 1).

そして、特許文献1には、上記の条件で熱処理を行うと、それまで、金属微粒子の表面を被覆していた分散剤が熱分解されて除去された後、表面が露呈した金属微粒子が焼結されるため、多数の金属微粒子が緻密に充てんされた、良好な金属被膜を形成できるとの知見が示されている。
特開2002−334618号公報(請求項1〜12、第0012欄〜第0020欄)
In Patent Document 1, when heat treatment is performed under the above-described conditions, the dispersing agent that has previously covered the surface of the metal fine particles is thermally decomposed and removed, and then the metal fine particles exposed on the surface are sintered. Therefore, it has been shown that a good metal film can be formed in which a large number of fine metal particles are densely packed.
JP 2002-334618 A (claims 1 to 12, columns 0012 to 0020)

しかし、発明者が検討したところ、上記形成方法のうち、熱処理の工程を、特許文献1の各実施例に記載されているように、不活性雰囲気中で行うと、形成される金属被膜は、ある程度は緻密なものとなるものの、基材、特に、ガラス基材等との密着性が低く、基材からはく離しやすいことが判った。この原因を明らかとするため、形成された金属被膜の分析を行ったところ、当該金属被膜中に、4重量%程度という多量の、分散剤に起源を有する炭素原子が含まれており、この炭素原子が、金属被膜と、基材との密着を妨げていることが判明した。   However, when the inventor examined, among the above formation methods, the heat treatment step performed in an inert atmosphere as described in each example of Patent Document 1, the metal film formed is Although it becomes dense to some extent, it has been found that it has low adhesion to a substrate, particularly a glass substrate, and is easily peeled off from the substrate. In order to clarify this cause, the formed metal film was analyzed. As a result, the metal film contained a large amount of carbon atoms originating from the dispersing agent of about 4% by weight. It was found that the atoms hindered the adhesion between the metal coating and the substrate.

本発明は、多数の金属微粒子を焼結させて形成され、緻密で、しかも基材に対する密着性にも優れた金属被膜と、その形成方法とを提供することにある。   An object of the present invention is to provide a dense metal film that is formed by sintering a large number of metal fine particles and that is excellent in adhesion to a substrate, and a method for forming the metal film.

熱処理の工程を、酸素を含む酸化性雰囲気中で行えば、分散剤起源の炭素原子を極力、除去することは可能である。しかし、その場合には、金属微粒子を形成する、銀や金等の金属元素が酸化されて、金属被膜の導電性が著しく低下してしまう。そこで、発明者は、金属微粒子を、上記銀や金等の、主に導電性を維持するための金属元素と、これらの金属元素よりも酸化性の高い、パラジウムや銅等の金属元素(以下「酸化性金属元素」と記載する場合がある)との合金または複合体によって形成して、酸化性雰囲気中での熱処理によって、分散剤起源の炭素原子を除去すると共に、上記熱処理時に、酸化性金属元素を積極的に酸化させることで、銀や金等の金属元素の酸化を、極力、抑制することを検討した。   If the heat treatment step is performed in an oxidizing atmosphere containing oxygen, it is possible to remove carbon atoms originating from the dispersant as much as possible. However, in that case, metal elements such as silver and gold that form the metal fine particles are oxidized, and the conductivity of the metal film is significantly lowered. Therefore, the inventor used metal fine particles, such as silver and gold, mainly for maintaining electrical conductivity, and metal elements such as palladium and copper (hereinafter referred to as “palladium” and “copper”) that have higher oxidation properties than these metal elements. In some cases, the carbon atoms originating from the dispersant are removed by heat treatment in an oxidizing atmosphere, and the oxidizing agent is oxidized during the heat treatment. We studied to suppress oxidation of metal elements such as silver and gold as much as possible by actively oxidizing metal elements.

ところが、この方法で形成された金属被膜は、多数の、粗大なボイドを有するものとなってしまい、緻密な金属被膜を形成することができなかった。この原因について検討したところ、金属微粒子中に含まれる、酸化性金属元素の酸化物が、金属微粒子同士の焼結を妨げていることが判明した。そこで、発明者はさらに検討した結果、酸化性雰囲気中で熱処理を行うことで、先に説明した、分散剤起源の炭素原子の含有量が所定値以下に抑制された金属被膜を、さらに、還元性雰囲気中で再度、熱処理して、酸化性金属元素の酸化物を還元して、その含有量を所定値以下に抑制してやれば、多数の金属微粒子をより緻密に焼結させて、緻密で、しかも基材に対する密着性にも優れた金属被膜が得られることを見出した。   However, the metal film formed by this method has a large number of coarse voids, and a dense metal film cannot be formed. When this cause was examined, it became clear that the oxide of the oxidizing metal element contained in the metal fine particles hindered the sintering of the metal fine particles. Therefore, as a result of further examination, the inventors further reduced the metal film in which the content of carbon atoms originating from the dispersant was suppressed to a predetermined value or less by performing heat treatment in an oxidizing atmosphere. If heat treatment is performed again in an oxidizing atmosphere to reduce the oxide of the oxidizing metal element and its content is suppressed to a predetermined value or less, a large number of fine metal particles are sintered more densely, And it discovered that the metal film excellent also in the adhesiveness with respect to a base material is obtained.

すなわち、請求項1記載の発明は、基材の表面に、金属微粒子分散液を印刷または塗布し、乾燥させて形成した塗膜を熱処理して形成される金属被膜であって、金属微粒子分散液は、金属微粒子と、炭素原子を含む分散剤とを含み、金属微粒子は、当該金属微粒子を形成する金属元素と、当該金属元素より酸化性の高い酸化性金属元素の少なくとも1種との合金または複合体であり、金属被膜中に含まれる炭素原子の含有量が1重量%以下で、かつ、金属被膜中に含まれる酸化性金属元素の総量中に占める、当該酸化性金属元素の酸化物の含有量が5重量%以下であることを特徴とする金属被膜である。   That is, the invention described in claim 1 is a metal film formed by printing or coating a metal fine particle dispersion on the surface of a substrate and drying the film formed by heat treatment. Includes a metal fine particle and a dispersant containing a carbon atom, and the metal fine particle is an alloy of a metal element that forms the metal fine particle and at least one of an oxidizing metal element that is more oxidizable than the metal element, or The oxide of the oxidizable metal element, which is a composite and has a carbon atom content of 1% by weight or less in the metal film and occupies the total amount of the oxidizable metal element in the metal film. The metal coating is characterized in that the content is 5% by weight or less.

また、請求項4記載の発明は、請求項1記載の金属被膜を形成する方法であって、基材の表面に、金属元素と、当該金属元素より酸化性の高い酸化性金属元素の少なくとも1種との合金または複合体からなる金属微粒子と、炭素原子を含む分散剤とを含む金属微粒子分散液を印刷または塗布し、乾燥させて塗膜を形成する工程と、形成した塗膜を、まず、酸化性雰囲気中で熱処理した後、還元性雰囲気中で再度、熱処理する工程とを含むことを特徴とする金属被膜の形成方法である。   The invention according to claim 4 is a method for forming the metal film according to claim 1, wherein at least one of a metal element and an oxidizing metal element having a higher oxidation property than the metal element is formed on the surface of the substrate. First, a step of printing or applying a metal fine particle dispersion containing a metal fine particle comprising an alloy or a composite with a seed and a dispersant containing carbon atoms and drying to form a coating film, And a step of heat-treating again in a reducing atmosphere after heat-treating in an oxidizing atmosphere.

なお、金属被膜に良好な導電性を付与することを考慮すると、金属被膜のもとになる金属微粒子は、導電性に寄与しない酸化性金属元素の含有割合を、30重量%以下に抑制した合金または複合体によって形成するのが好ましい。したがって、請求項2記載の発明は、酸化性金属元素を30重量%以下の割合で含有する合金または複合体からなる金属微粒子を用いて形成される請求項1記載の金属被膜である。   In consideration of imparting good electrical conductivity to the metal coating, the metal fine particles that form the metal coating are alloys in which the content of the oxidizing metal element that does not contribute to electrical conductivity is suppressed to 30% by weight or less. Or it is preferable to form by a composite_body | complex. Therefore, the invention according to claim 2 is the metal film according to claim 1 formed by using metal fine particles made of an alloy or a composite containing an oxidizing metal element in a proportion of 30% by weight or less.

同様に、金属被膜に良好な導電性を付与することを考慮すると、金属微粒子を形成する金属元素としては、導電性に優れた銀および金のうちの少なくとも一方が好ましい。また、銀や金と合金または複合体を形成して、酸化性雰囲気中で熱処理した際に、自身が酸化されることで、上記銀や金の酸化を抑制する酸化性金属元素としては、パラジウム、銅、スズ、ニッケルおよびコバルトからなる群より選ばれた少なくとも1種が好ましい。したがって、請求項3記載の発明は、銀および金のうちの少なくとも一方と、酸化性金属元素としての、パラジウム、銅、スズ、ニッケルおよびコバルトからなる群より選ばれた少なくとも1種との合金または複合体からなる金属微粒子を用いて形成される請求項1記載の金属被膜である。   Similarly, in consideration of imparting good conductivity to the metal coating, the metal element forming the metal fine particles is preferably at least one of silver and gold having excellent conductivity. As an oxidizing metal element that suppresses the oxidation of silver or gold by forming an alloy or composite with silver or gold and heat-treating in an oxidizing atmosphere, the metal itself is oxidized. At least one selected from the group consisting of copper, tin, nickel and cobalt is preferred. Therefore, the invention according to claim 3 is an alloy of at least one of silver and gold and at least one selected from the group consisting of palladium, copper, tin, nickel and cobalt as an oxidizing metal element, or The metal film according to claim 1, wherein the metal film is formed using metal fine particles made of a composite.

また、本発明の形成方法において、形成される金属被膜中に含まれる、分散剤起源の炭素原子の含有量を、できるだけ効率的に低減させるためには、酸化性雰囲気中での熱処理を、150℃以上の温度で行うのが好ましい。したがって、請求項5記載の発明は、酸化性雰囲気中での熱処理を、150℃以上の温度で行う請求項4記載の金属被膜の形成方法である。   Further, in the formation method of the present invention, in order to reduce the content of carbon atoms originating from the dispersant contained in the formed metal film as efficiently as possible, heat treatment in an oxidizing atmosphere is performed at 150. It is preferable to carry out at a temperature of at least ° C. Accordingly, the invention according to claim 5 is the method for forming a metal film according to claim 4, wherein the heat treatment in an oxidizing atmosphere is performed at a temperature of 150 ° C. or higher.

さらに、本発明の形成方法において、形成される金属被膜中に含まれる、酸化性金属元素の酸化物の含有量を、できるだけ効率的に低減させるためには、還元性雰囲気中での熱処理を、150℃異常の温度で行うのが好ましい。したがって、請求項6記載の発明は、還元性雰囲気中での熱処理を、150℃以上の温度で行う請求項4記載の金属被膜の形成方法である。   Furthermore, in the forming method of the present invention, in order to reduce the content of the oxide of the oxidizing metal element contained in the formed metal film as efficiently as possible, a heat treatment in a reducing atmosphere is performed. It is preferable to carry out at an abnormal temperature of 150 ° C. Accordingly, the invention according to claim 6 is the method for forming a metal film according to claim 4, wherein the heat treatment in a reducing atmosphere is performed at a temperature of 150 ° C. or higher.

本発明の金属被膜は、前記のように、基材の表面に、金属微粒子を形成する金属元素と、当該金属元素より酸化性の高い酸化性金属元素の少なくとも1種との合金または複合体からなる金属微粒子と、炭素原子を含む分散剤とを含む金属微粒子分散液を印刷または塗布し、乾燥させて形成した塗膜を熱処理して形成されるものであって、炭素原子の含有量が1重量%以下で、かつ、酸化性金属元素の総量中に占める、当該酸化性金属元素の酸化物の含有量が5重量%以下であることを特徴とするものである。   As described above, the metal coating of the present invention is formed from an alloy or a composite of a metal element that forms fine metal particles on the surface of a base material and at least one oxidizing metal element that is more oxidizing than the metal element. It is formed by heat-treating a coating film formed by printing or applying a metal fine particle dispersion liquid containing a metal fine particle and a carbon atom-containing dispersant and drying it, and has a carbon atom content of 1 The content of the oxide of the oxidizable metal element in the total amount of the oxidizable metal element is 5% by weight or less.

金属被膜における、分散剤起源の炭素原子の含有量が、1重量%以下に限定されるのは、炭素原子の含有量がこの範囲を超える金属被膜は、先に説明したように、基材、特に、ガラス基材等との密着性が低く、基材からはく離しやすいためである。なお、基材との密着性に優れた金属被膜を得ることを考慮すると、炭素原子の含有量は、上記の範囲内でも、特に、0.5重量%以下であるのが好ましい。   In the metal coating, the content of carbon atoms originating from the dispersant is limited to 1% by weight or less. As described above, the metal coating having a carbon atom content exceeding this range is the base material, In particular, the adhesiveness with a glass substrate or the like is low and it is easy to peel off from the substrate. In consideration of obtaining a metal film having excellent adhesion to the substrate, the carbon atom content is preferably 0.5% by weight or less, even within the above range.

金属被膜における炭素原子の含有量は、少なければ少ないほど好ましく、0重量%であるのが理想である。しかし、後述する、酸化性雰囲気中での熱処理等によって、金属被膜中に残留する炭素原子を、完全に除去することは難しく、基材との密着性と、処理の効率化との兼ね合い等を考慮すると、含有量が上記の範囲内まで減少していれば、それで十分である。金属元素における炭素原子の含有量は、元素分析装置等を用いて測定することができる。   The content of carbon atoms in the metal coating is preferably as small as possible, and ideally 0% by weight. However, it is difficult to completely remove carbon atoms remaining in the metal film by heat treatment in an oxidizing atmosphere, which will be described later, and there is a balance between adhesion to the base material and efficiency of the treatment. In consideration, it is sufficient if the content is reduced to the above range. The carbon atom content in the metal element can be measured using an elemental analyzer or the like.

また、金属被膜に含まれる酸化性金属元素の総量中に占める、当該酸化性金属元素の酸化物の含有量が5重量%以下に限定されるのは、酸化物の含有量がこの範囲を超える金属被膜は、先に説明したように、多数の、粗大なボイドを有するものとなってしまい、緻密な金属被膜を形成することができないためである。なお、ボイドのない、できるだけ緻密な金属被膜を形成することを考慮すると、酸化性金属元素の酸化物の含有量は、上記の範囲内でも、特に、2重量%以下であるのが好ましい。   In addition, the oxide content of the oxidizable metal element in the total amount of the oxidizable metal element contained in the metal coating is limited to 5% by weight or less, and the oxide content exceeds this range. This is because the metal film has a large number of coarse voids as described above, and a dense metal film cannot be formed. In consideration of forming a metal film as dense as possible without voids, the content of the oxide of the oxidizing metal element is preferably 2% by weight or less, even within the above range.

ちなみに、この酸化物の含有量も、少なければ少ないほど好ましく、0重量%であるのが理想的であるが、後述する、還元性雰囲気中での熱処理などによって、金属被膜中に含まれる酸化性金属元素の酸化物を完全に還元することは難しく、ボイドのない緻密な金属被膜を形成することと、処理の効率化との兼ね合い等を考慮すると、含有量が上記の範囲内まで減少していれば、それで十分である。金属被膜に含まれる酸化性金属元素の総量中に占める、酸化性金属元素の酸化物の含有量は、金属微粒子の組成比から求められる、金属被膜中の酸化性金属元素の含有量と、元素分析装置等を用いて測定した、金属被膜中の酸素原子の量とから、算出することができる。   Incidentally, the smaller the content of this oxide, the better. It is ideal that it is 0% by weight, but it is ideal that the oxide is contained in the metal film by heat treatment in a reducing atmosphere, which will be described later. It is difficult to completely reduce the oxide of the metal element, and considering the balance between forming a dense metal film without voids and increasing the efficiency of processing, the content has decreased to the above range. If so, that is enough. The content of the oxide of the oxidizing metal element in the total amount of the oxidizing metal element contained in the metal coating is determined from the composition ratio of the metal fine particles, the content of the oxidizing metal element in the metal coating and the element It can be calculated from the amount of oxygen atoms in the metal film measured using an analyzer or the like.

金属被膜のもとになる金属微粒子は、酸化性金属元素の含有割合を、30重量%以下に設定した合金または複合体によって形成するのが好ましい。酸化性金属元素の含有割合が30重量%を超える場合には、当該酸化性金属元素が、金属被膜の導電性が低下する原因となるため、形成される金属被膜の導電性が低下して、導体回路等として必要な導電性が得られないおそれがある。   The metal fine particles that form the metal coating are preferably formed of an alloy or composite in which the content of the oxidizing metal element is set to 30% by weight or less. When the content ratio of the oxidizable metal element exceeds 30% by weight, the oxidizable metal element causes a decrease in the conductivity of the metal film, so that the conductivity of the formed metal film decreases, There is a risk that the conductivity necessary for a conductor circuit or the like cannot be obtained.

ただし、酸化性金属元素の含有割合が少なすぎる場合には、酸化性雰囲気中での熱処理時に、当該酸化性金属元素を積極的に酸化させることで、銀や金等の金属元素の酸化を抑制する効果が十分に得られないおそれがある。そのため、酸化性金属元素の含有割合は、上記の範囲内でも、特に、1重量%以上であるのが好ましい。なお、酸化性金属元素の含有割合は、酸化性金属元素を1種単独で使用する場合は、その酸化性金属元素の含有割合であり、2種以上の酸化性金属元素を併用する場合は、その合計の含有割合である。   However, when the content of the oxidizing metal element is too small, the oxidation of the metal element such as silver or gold is suppressed by positively oxidizing the oxidizing metal element during the heat treatment in the oxidizing atmosphere. There is a possibility that the effect to do is not sufficiently obtained. Therefore, the content ratio of the oxidizing metal element is particularly preferably 1% by weight or more even within the above range. In addition, the content rate of an oxidizable metal element is the content rate of the oxidizable metal element when the oxidizable metal element is used alone, and when two or more oxidizable metal elements are used in combination, It is the total content ratio.

また、金属被膜に良好な導電性を付与することを考慮すると、金属微粒子を形成する金属元素としては、導電性に優れた銀および金のうちの少なくとも一方が好ましい。また、銀や金と合金または複合体を形成して、酸化性雰囲気中で熱処理した際に、自身が酸化されることで、上記銀や金の酸化を抑制する酸化性金属元素としては、パラジウム、銅、スズ、ニッケルおよびコバルトからなる群より選ばれた少なくとも1種が好ましい。金属元素と酸化性金属元素との複合体としては、両金属元素の単なる混合物や、金属元素からなる微粒子の表面を、酸化性金属元素で被覆した層状構造体等が挙げられる。   In consideration of imparting good conductivity to the metal coating, the metal element forming the metal fine particles is preferably at least one of silver and gold having excellent conductivity. As an oxidizing metal element that suppresses the oxidation of silver or gold by forming an alloy or composite with silver or gold and heat-treating in an oxidizing atmosphere, the metal itself is oxidized. At least one selected from the group consisting of copper, tin, nickel and cobalt is preferred. Examples of the composite of the metal element and the oxidizing metal element include a simple mixture of both metal elements, a layered structure in which the surface of fine particles made of the metal element is covered with the oxidizing metal element, and the like.

金属微粒子の粒径は、特に限定されないが、できるだけ緻密な金属被膜を形成することを考慮すると、一次粒子径が200nm以下であるのが好ましく150nm以下であるのがさらに好ましい。また、金属微粒子の一次粒子径の下限については、特に限定されないが、実用上は、1nm以上であるのが好ましい。金属微粒子の一次粒子径は、本発明では、レーザードップラー法を応用した粒度分布測定装置を用いて測定される粒度分布のピーク値でもって規定することとする。   The particle diameter of the metal fine particles is not particularly limited, but considering that a metal film as dense as possible is formed, the primary particle diameter is preferably 200 nm or less, and more preferably 150 nm or less. Further, the lower limit of the primary particle diameter of the metal fine particles is not particularly limited, but is preferably 1 nm or more for practical use. In the present invention, the primary particle diameter of the metal fine particles is defined by the peak value of the particle size distribution measured using a particle size distribution measuring apparatus applying the laser Doppler method.

なお、上記金属微粒子を焼結させて形成される金属被膜がどの程度緻密で、表面が平滑であるかの基準として、日本工業規格JIS B0601:2001「製品の幾何特性仕様(GPS)−表面性状:輪郭曲線方式−用語,定義及び表面性状パラメータ」によって規定された算術平均高さRaが、金属微粒子の一次粒子径の2倍以下であるのが好ましい。表面の算術平均高さRaがこの範囲内であれば、金属被膜は、緻密で、表面平滑性に優れたものであると言える。   In addition, as a standard of how dense and smooth the metal coating formed by sintering the above metal fine particles is, Japanese Industrial Standard JIS B0601: 2001 “Product Geometric Characteristics Specification (GPS) —Surface Properties” It is preferable that the arithmetic average height Ra defined by “: Contour Curve Method—Terminology, Definition, and Surface Property Parameter” is not more than twice the primary particle diameter of the metal fine particles. If the arithmetic average height Ra of the surface is within this range, it can be said that the metal film is dense and excellent in surface smoothness.

金属微粒子は、含浸法と呼ばれる高温処理法や、液相還元法、気相法などの、従来公知の種々の方法によって製造することができる。このうち、液相還元法によって、金属元素と、酸化性金属元素との合金からなる金属微粒子を製造するためには、例えば、水に、金属微粒子を形成する上記金属元素、および酸化性金属元素の、それぞれのイオンのもとになる水溶性の金属化合物と、分散剤とを溶解すると共に、還元剤を加えて、好ましくは、かく拌下、一定時間、両金属元素のイオンを還元反応させればよい。かかる液相還元法によって製造される金属微粒子は、形状が球状ないし粒状で揃っていると共に、粒度分布がシャープで、しかも、一次粒子径が小さいという特徴を有している。   The metal fine particles can be produced by various conventionally known methods such as a high temperature treatment method called an impregnation method, a liquid phase reduction method, and a gas phase method. Among these, in order to produce metal fine particles made of an alloy of a metal element and an oxidizing metal element by a liquid phase reduction method, for example, the above metal element that forms metal fine particles in water, and an oxidizing metal element In addition to dissolving the water-soluble metal compound that is the source of each ion and the dispersant, a reducing agent is added, and preferably, the ions of both metal elements are reduced and reacted for a certain period of time under stirring. Just do it. The metal fine particles produced by such a liquid phase reduction method are characterized by having a spherical or granular shape, a sharp particle size distribution, and a small primary particle size.

金属元素のイオンのもとになる、水溶性の金属化合物としては、例えば、銀の場合は、硝酸銀(I)〔AgNO3〕やメタンスルホン酸銀〔CH3SO3Ag〕等が挙げられ、金の場合は、テトラクロロ金(III)酸四水和物〔HAuCl4・4H2O〕等が挙げられる。また、酸化性金属元素のイオンのもとになる、水溶性の金属化合物としては、例えば、パラジウムの場合は、硝酸パラジウム(II)硝酸溶液〔Pd(NO2)2/H2O〕や塩化パラジウム(II)溶液〔PdCl2〕等が挙げられ、銅の場合は、硝酸銅(II)〔Cu(NO3)2〕や硫酸銅(II)五水和物〔CuSO4・5H2O〕等が挙げられる。さらに、ニッケルの場合は、塩化ニッケル(II)六水和物〔NiCl2・6H2O〕や硝酸ニッケル(II)六水和物〔Ni(NO3)2・6H2O〕等が挙げられ、スズの場合は、塩化スズ(IV)五水和物〔SnCl4・5H2O〕等が挙げられる。 Examples of the water-soluble metal compound that is a source of metal element ions include silver nitrate (I) [AgNO 3 ] and silver methanesulfonate [CH 3 SO 3 Ag] in the case of silver. In the case of gold, tetrachloroauric (III) acid tetrahydrate [HAuCl 4 · 4H 2 O] and the like can be mentioned. Examples of the water-soluble metal compound that is the source of the oxidizing metal element ion include palladium (II) nitrate solution [Pd (NO 2 ) 2 / H 2 O] and chloride in the case of palladium. Palladium (II) solution [PdCl 2 ] and the like can be mentioned. In the case of copper, copper nitrate (II) [Cu (NO 3 ) 2 ] or copper sulfate (II) pentahydrate [CuSO 4 .5H 2 O] Etc. Further, in the case of nickel, nickel chloride (II) hexahydrate [NiCl 2 · 6H 2 O], nickel nitrate (II) hexahydrate [Ni (NO 3 ) 2 · 6H 2 O] and the like can be mentioned. In the case of tin, tin (IV) chloride pentahydrate [SnCl 4 .5H 2 O] and the like can be mentioned.

還元剤としては、液相の反応系中で、金属元素および酸化性金属元素のイオンを還元することで、両金属元素の合金からなる金属微粒子として析出させることができる種々の還元剤が、いずれも使用可能である。かかる還元剤としては、例えば、水素化ホウ素ナトリウム、次亜リン酸ナトリウム、ヒドラジン、遷移金属元素のイオン(三価のチタンイオン、二価のコバルトイオン等)が挙げられる。ただし、析出させる金属微粒子の一次粒子径をできるだけ小さくするためには、金属のイオンの還元、析出速度を遅くするのが有効であり、還元、析出速度を遅くするためには、できるだけ還元力の弱い還元剤を選択して使用することが好ましい。   As the reducing agent, various reducing agents that can be precipitated as metal fine particles made of an alloy of both metal elements by reducing ions of the metal element and the oxidizing metal element in a liquid phase reaction system, Can also be used. Examples of the reducing agent include sodium borohydride, sodium hypophosphite, hydrazine, and transition metal element ions (trivalent titanium ions, divalent cobalt ions, and the like). However, in order to reduce the primary particle size of the metal fine particles to be precipitated as much as possible, it is effective to reduce the reduction and precipitation rate of metal ions, and to reduce the reduction and precipitation rate, the reduction power is as low as possible. It is preferable to select and use a weak reducing agent.

還元力の弱い還元剤としては、例えば、メタノール、エタノール、2−プロパノール等のアルコールや、あるいはアスコルビン酸等を挙げることができる他、エチレングリコール、グルタチオン、有機酸類(クエン酸、リンゴ酸、酒石酸等)、還元性糖類(グルコース、ガラクトース、マンノース、フルクトース、スクロース、マルトース、ラフィノース、スタキオース等)、および糖アルコール類(ソルビトール等)等を挙げることができ、中でも、還元性糖類や、その誘導体としての糖アルコール類が好ましい。   Examples of the reducing agent having a weak reducing power include alcohols such as methanol, ethanol and 2-propanol, ascorbic acid, and the like, as well as ethylene glycol, glutathione, organic acids (citric acid, malic acid, tartaric acid, etc.) ), Reducing saccharides (glucose, galactose, mannose, fructose, sucrose, maltose, raffinose, stachyose, etc.) and sugar alcohols (sorbitol, etc.), among others, as reducing saccharides and their derivatives Sugar alcohols are preferred.

分散剤としては、水に対して良好な溶解性を有する、種々の分散剤が、いずれも使用可能であるが、特に、酸化性雰囲気中での熱処理によってスムースに熱分解させることを考慮すると、分子量100000以下程度の分散剤が、好適に使用される。また、分散剤としては、形成される金属被膜や、この金属被膜を導体回路として用いた際に、その近傍に配置される電子部品等が劣化するのを防止することを考慮すると、硫黄、リン、ホウ素およびハロゲン原子を含まない有機化合物が好ましい。これらの条件を満足する、好適な分散剤としては、例えば、ポリエチレンイミン、ポリビニルピロリドン等のアミン系の高分子分散剤や、ポリアクリル酸、カルボキシメチルセルロース等の、分子中にカルボン酸基を有する炭化水素系の高分子分散剤、ポバール(ポリビニルアルコール)、あるいは、1分子中に、ポリエチレンイミン部分とポリエチレンオキサイド部分とを有する共重合体等の、高分子分散剤が挙げられる。   As the dispersant, various dispersants having good solubility in water can be used, but in particular, considering that they are thermally decomposed smoothly by heat treatment in an oxidizing atmosphere, A dispersant having a molecular weight of about 100,000 or less is preferably used. Further, as the dispersant, considering that the formed metal film and the electronic parts disposed in the vicinity of the metal film used as a conductor circuit are prevented from deteriorating, sulfur, phosphorus, Organic compounds containing no boron and halogen atoms are preferred. Suitable dispersants that satisfy these conditions include, for example, amine-based polymer dispersants such as polyethyleneimine and polyvinylpyrrolidone, carbonization having a carboxylic acid group in the molecule such as polyacrylic acid and carboxymethylcellulose. Examples thereof include a hydrogen-based polymer dispersant, poval (polyvinyl alcohol), and a polymer dispersant such as a copolymer having a polyethyleneimine moiety and a polyethylene oxide moiety in one molecule.

金属微粒子の一次粒子径を、前記の範囲に調整するには、金属化合物、分散剤、還元剤の種類と配合割合とを調整すると共に、金属化合物を還元反応させる際に、かく拌速度、温度、時間、pH等を調整すればよい。   In order to adjust the primary particle diameter of the metal fine particles to the above range, the metal compound, the dispersant, the kind of the reducing agent and the blending ratio are adjusted, and when the metal compound is subjected to a reduction reaction, the stirring speed and temperature are adjusted. The time, pH, etc. may be adjusted.

本発明の金属被膜は、基材の表面に、上記金属微粒子と、炭素原子を含む分散剤とを含む金属微粒子分散液を印刷または塗布し、乾燥させて形成した塗膜を、まず、酸化性雰囲気中で熱処理した後、還元性雰囲気中で再度、熱処理する本発明の形成方法によって形成することができる。   The metal coating of the present invention is obtained by printing or applying a metal fine particle dispersion containing the above metal fine particles and a carbon atom-containing dispersant on the surface of a base material, followed by drying. After the heat treatment in the atmosphere, the film can be formed by the forming method of the present invention in which the heat treatment is performed again in the reducing atmosphere.

金属微粒子が、先に説明したように、液相還元法によって製造される場合には、還元反応によって金属微粒子を析出させた後の反応溶液を、そのままで、基材の表面に塗布して塗膜を形成するための金属微粒子分散液として使用することもできる。また、製造した金属微粒子を、適当な溶媒に分散させて新たな金属微粒子分散液を調製して、塗膜の形成に使用することもできる。新たな金属微粒子分散液を調製するための溶媒としては、水、または、水と水溶性有機溶媒との混合溶媒が挙げられる。   As described above, when the metal fine particles are produced by the liquid phase reduction method, the reaction solution after the metal fine particles are precipitated by the reduction reaction is directly applied to the surface of the base material. It can also be used as a metal fine particle dispersion for forming a film. Further, the produced metal fine particles can be dispersed in a suitable solvent to prepare a new metal fine particle dispersion, which can be used for forming a coating film. Examples of the solvent for preparing a new metal fine particle dispersion include water or a mixed solvent of water and a water-soluble organic solvent.

水溶性有機溶媒としては、例えば、メタノール、エタノール、n−プロパノール、2−プロパノール、2−エトキシエタノール、グリセリン、ジプロピレングリコール、エチレングリコール、ポリエチレングリコール等のアルコール類;アセトン、メチルエチルケトン等のケトン類;エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノブチルエーテル、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノブチルエーテル、ジエチレングリコールジメチルエーテル、ジエチレングリコールジエチルエーテル、トリエチレングリコールモノブチルエーテル、ジプロピレングリコールモノメチルエーテル、ジプロピレングリコールモノエチルエーテル、トリプロピレングリコールモノメチルエーテル等のグリコールエーテル類;2−ピロリドン、N−メチルピロリドン等の水溶性の含窒素有機化合物類;および酢酸エチル等が挙げられる。水溶性有機溶媒は、それぞれ1種単独で使用できる他、2種以上を併用することもできる。   Examples of the water-soluble organic solvent include alcohols such as methanol, ethanol, n-propanol, 2-propanol, 2-ethoxyethanol, glycerin, dipropylene glycol, ethylene glycol, and polyethylene glycol; ketones such as acetone and methyl ethyl ketone; Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene Glico Monoethyl ether, glycol ethers such as tripropylene glycol monomethyl ether; 2-pyrrolidone, water-soluble nitrogen-containing organic compounds such as N- methyl pyrrolidone; and ethyl acetate. The water-soluble organic solvent can be used alone or in combination of two or more.

本発明では、金属微粒子分散液を用いて塗膜を形成するための印刷方法や塗布方法に最適な物性を有するように、分散媒として、水や水溶性有機溶媒を用い、その配合割合や、水溶性有機溶媒の種類、あるいは、2種以上の水溶性有機溶媒を併用する場合は、その組み合わせ等が適宜、選択される。例えば、インクジェット印刷法やスピンコート法、スプレー法による塗膜の形成においては、金属微粒子分散液が、できるだけ低粘度であることが求められ、逆に、スクリーン印刷法やロールコート法による塗膜の形成では、金属微粒子分散液が、高粘度であることが求められる。さらに、ディップコート法による塗膜の形成においては、金属微粒子分散液が、上記の中間の、適度な粘度を有していることが求められる。   In the present invention, water or a water-soluble organic solvent is used as a dispersion medium so as to have optimum physical properties for a printing method and a coating method for forming a coating film using a metal fine particle dispersion, When a water-soluble organic solvent is used in combination, or when two or more water-soluble organic solvents are used in combination, the combination thereof is appropriately selected. For example, in the formation of a coating film by an inkjet printing method, a spin coating method, or a spray method, the metal fine particle dispersion is required to have a viscosity as low as possible, and conversely, a coating film by a screen printing method or a roll coating method is required. In the formation, the metal fine particle dispersion is required to have a high viscosity. Furthermore, in the formation of a coating film by the dip coating method, the metal fine particle dispersion is required to have an intermediate and appropriate viscosity.

そこで、これらの物性を満足するために、水と、水溶性有機溶媒との配合割合や、水溶性有機溶媒の種類、2種以上の水溶性有機溶媒を併用する場合の組み合わせ等が選択される。また、それとともに、金属微粒子の一次粒子径や配合割合、分散剤の分子量や配合割合、分散剤の種類等も、選択される。   Therefore, in order to satisfy these physical properties, the mixing ratio of water and the water-soluble organic solvent, the type of the water-soluble organic solvent, the combination in the case of using two or more water-soluble organic solvents in combination, and the like are selected. . At the same time, the primary particle size and blending ratio of the metal fine particles, the molecular weight and blending ratio of the dispersant, the type of the dispersant, and the like are also selected.

金属微粒子分散液は、従来同様に、金属微粒子を、ロ別、洗浄、乾燥、解砕等の各工程を経て粉末状とした後、必要に応じて追加の分散剤と共に、分散媒中に分散させて製造することができる。しかし、金属微粒子分散液は、前記のように水中で、金属のイオンを還元して金属微粒子を析出させた後の、液相の反応系から、析出させた金属微粒子を完全に分離する工程を経ることなしに、製造するのがより好ましい。   In the same way as before, the metal fine particle dispersion is made into a powder form through various steps such as separation, washing, drying and crushing, and then dispersed in a dispersion medium with an additional dispersant as necessary. Can be manufactured. However, the metal fine particle dispersion has a step of completely separating the precipitated metal fine particles from the liquid phase reaction system after reducing the metal ions in water and precipitating the metal fine particles in water as described above. It is more preferable to manufacture without going through.

具体的には、金属微粒子を析出させた後の、液相の反応系を遠心分離して、金属微粒子より軽い不純物を除去したり、水洗して水溶性の不純物を除去したりし、次いで、例えば、ロータリーエバポレータを用いたり、加熱したり、あるいは、再び遠心分離して上澄み液を除去したりすることで、所定の濃度に濃縮した後、所定量の水および/または水溶性有機溶媒を加えることによって金属微粒子分散液が製造される。この際、反応系中には、金属微粒子の製造に使用した分散剤が含まれているため、通常は必要ないが、場合によっては、前記と同様の分散剤を新たに追加してもよい。   Specifically, the liquid phase reaction system after depositing the metal fine particles is centrifuged to remove impurities lighter than the metal fine particles, or washed with water to remove water-soluble impurities, For example, use a rotary evaporator, heat, or centrifuge again to remove the supernatant liquid, concentrate to a predetermined concentration, and then add a predetermined amount of water and / or water-soluble organic solvent As a result, a metal fine particle dispersion is produced. At this time, since the dispersant used for the production of the metal fine particles is contained in the reaction system, it is usually not necessary, but in some cases, a dispersant similar to the above may be newly added.

上記の工程を経て製造される金属微粒子分散液は、金属微粒子の凝集による粗大で不定形な粒子の発生を防止して、液相還元法によって形成される金属微粒子の、形状が球状ないし粒状で揃っていると共に、粒度分布がシャープで、しかも、一次粒子径が小さいという特徴をそのまま維持することができる。したがって、上記の金属微粒子分散液を用いて塗膜を形成すれば、その後の熱処理によって、塗膜中の金属微粒子を均一に凝集させることができるため、基材2の表面に、粒径および形状の揃った金属粒子3を、均一に分布させることができる。   The metal fine particle dispersion produced through the above steps prevents the generation of coarse and irregular particles due to aggregation of the metal fine particles, and the metal fine particles formed by the liquid phase reduction method have a spherical or granular shape. In addition, the characteristics that the particle size distribution is sharp and the primary particle diameter is small can be maintained as they are. Therefore, if a coating film is formed using the above-described metal fine particle dispersion, the metal fine particles in the coating film can be uniformly aggregated by the subsequent heat treatment. The uniform metal particles 3 can be distributed uniformly.

なお、気相法で製造された金属微粒子は、通常、有機溶媒中に分散させた分散液の状態で供給されることから、金属微粒子として、気相法で製造されたものを使用する場合は、供給される分散液を、そのままで、金属微粒子分散液として、塗膜の形成に使用すればよい。   In addition, since the metal fine particles produced by the vapor phase method are usually supplied in the state of a dispersion dispersed in an organic solvent, when using the metal fine particles produced by the vapor phase method, The supplied dispersion liquid may be used as it is for forming a coating film as a metal fine particle dispersion liquid.

本発明の形成方法においては、次に、基材の表面に形成した塗膜を、まず、酸化性雰囲気中で熱処理する。そうすると、塗膜中で、金属微粒子の表面を被覆していた分散剤が熱分解されて、分散剤起源の炭素原子の含有量が1重量%以下となるまで分散剤が除去されると共に、表面が露呈した金属微粒子が焼結される。また、この際、金属微粒子中に含まれる酸化性金属元素が積極的に酸化されることで、銀や金等の金属元素の酸化が抑制される。   In the forming method of the present invention, next, the coating film formed on the surface of the substrate is first heat-treated in an oxidizing atmosphere. Then, in the coating film, the dispersant covering the surface of the metal fine particles is thermally decomposed, and the dispersant is removed until the content of carbon atoms originating from the dispersant is 1% by weight or less. The metal fine particles exposed are sintered. At this time, the oxidizing metal element contained in the metal fine particles is positively oxidized, so that the oxidation of the metal element such as silver or gold is suppressed.

酸化性雰囲気中での熱処理の条件は、特に限定されないが、熱処理の温度は、形成される金属被膜中に含まれる、分散剤起源の炭素原子の含有量を、できるだけ効率的に低減させるために、150℃以上であるのが好ましい。また、この範囲で、熱処理の温度を高くするほど、処理の時間を短くすることができるが、熱処理に要するエネルギー量を抑制することや、基材の耐熱性等を合わせ考慮すると、熱処理の温度は、上記の範囲内でも、600℃以下であるのが好ましい。また、熱処理の時間は、熱処理の温度に合わせて、適宜、設定することができる。さらに、酸化性雰囲気としては、金属被膜中に含まれる、分散剤起源の炭素原子の含有量を、できるだけ効率的に低減させることを考慮すると、酸素ガスを10体積%以上含む混合ガス雰囲気が好ましい。   The conditions for the heat treatment in the oxidizing atmosphere are not particularly limited, but the temperature of the heat treatment is to reduce the content of carbon atoms originating from the dispersant contained in the formed metal film as efficiently as possible. It is preferably 150 ° C. or higher. In this range, the higher the heat treatment temperature, the shorter the treatment time. However, considering the energy amount required for the heat treatment and the heat resistance of the base material, the heat treatment temperature is considered. Even within the above range, is preferably 600 ° C. or lower. Further, the heat treatment time can be appropriately set in accordance with the heat treatment temperature. Further, as the oxidizing atmosphere, a mixed gas atmosphere containing 10% by volume or more of oxygen gas is preferable in consideration of reducing the content of carbon atoms originating from the dispersant contained in the metal film as efficiently as possible. .

次に、本発明の形成方法においては、形成した金属被膜を、還元性雰囲気中で再度、熱処理する。そうすると、酸化性雰囲気中での熱処理によって金属被膜中に生成した、酸化性金属元素の酸化物が、還元性雰囲気によって還元されて、その含有量が、酸化性金属元素の総量中の5重量%以下まで低減されると共に、金属微粒子が再焼結されて、ボイドのない、緻密な金属被膜が形成される。   Next, in the forming method of the present invention, the formed metal film is heat-treated again in a reducing atmosphere. Then, the oxide of the oxidizing metal element generated in the metal film by the heat treatment in the oxidizing atmosphere is reduced by the reducing atmosphere, and the content thereof is 5% by weight in the total amount of the oxidizing metal element. In addition to being reduced to the following, the fine metal particles are re-sintered to form a dense metal film without voids.

還元性雰囲気中での熱処理の条件も、特に限定されないが、熱処理の温度は、金属被膜中に含まれる、酸化性金属元素の酸化物の含有量を、できるだけ効率的に低減させるために、150℃以上であるのが好ましい。また、この範囲で、熱処理の温度を高くするほど、処理の時間を短くすることができるが、熱処理に要するエネルギー量を抑制することや、基材の耐熱性等を合わせ考慮すると、熱処理の温度は、上記の範囲内でも、600℃以下であるのが好ましい。また、熱処理の時間は、熱処理の温度に合わせて、適宜、設定することができる。さらに、還元性雰囲気としては、金属被膜中に含まれる、酸化性金属元素の酸化物の含有量を、できるだけ効率的に低減させることを考慮すると、水素ガスを1体積%以上含む混合ガス雰囲気や、アンモニアガス雰囲気が好ましい。   The conditions for the heat treatment in the reducing atmosphere are not particularly limited, but the temperature of the heat treatment is 150 in order to reduce the oxide content of the oxidizing metal element contained in the metal film as efficiently as possible. It is preferable that the temperature is not lower than ° C. In this range, the higher the heat treatment temperature, the shorter the treatment time. However, considering the energy amount required for the heat treatment and the heat resistance of the base material, the heat treatment temperature is considered. Even within the above range, is preferably 600 ° C. or lower. Further, the heat treatment time can be appropriately set in accordance with the heat treatment temperature. Furthermore, as the reducing atmosphere, in consideration of reducing the content of the oxide of the oxidizing metal element contained in the metal coating as efficiently as possible, a mixed gas atmosphere containing 1% by volume or more of hydrogen gas, An ammonia gas atmosphere is preferred.

実施例1:
金属微粒子分散液としては、液相還元法で製造された、一次粒子径が20nmである銀−パラジウム合金微粒子(パラジウム含量:10重量%)を、分散剤としてのポリビニルピロリドン(分子量30000)と共に、水に分散して調製したものを用いた。そして、この金属微粒子分散液を、青板ガラス基板の表面に、スピンコート法によって塗布し、100℃で10分間、加熱して乾燥させて、厚み0.5μmの塗膜を形成した。なお、銀−パラジウム合金微粒子の一次粒子径は、先に説明したように、レーザードップラー法を応用した粒度分布測定装置〔日機装(株)製のナノトラック(登録商標)粒度分布測定装置UPA−EX1〕を用いて測定される粒度分布のピーク値で表した。
Example 1:
As the metal fine particle dispersion, silver-palladium alloy fine particles (palladium content: 10% by weight) produced by a liquid phase reduction method and having a primary particle diameter of 20 nm, together with polyvinylpyrrolidone (molecular weight 30000) as a dispersant, What was prepared by dispersing in water was used. And this metal fine particle dispersion was apply | coated to the surface of a soda glass substrate by the spin coat method, and it heated and dried at 100 degreeC for 10 minute (s), and formed the 0.5-micrometer-thick coating film. As described above, the primary particle size of the silver-palladium alloy fine particles is a particle size distribution measuring apparatus using a laser Doppler method [Nanotrack (registered trademark) particle size distribution measuring apparatus UPA-EX1 manufactured by Nikkiso Co., Ltd. ] Was represented by the peak value of the particle size distribution measured using

次に、上記塗膜が形成された青板ガラス基板を、400℃の酸化性雰囲気(酸素ガスと窒素ガスの混合ガス雰囲気、酸素ガス量20体積%)中で30分間、熱処理した後、引き続いて、450℃の還元性雰囲気(水素ガスと窒素ガスの混合ガス雰囲気、水素ガス量3体積%)中で30分間、熱処理した。そして、室温に冷却して金属被膜を得た。   Next, the soda-lime glass substrate on which the coating film is formed is heat-treated for 30 minutes in an oxidizing atmosphere at 400 ° C. (mixed gas atmosphere of oxygen gas and nitrogen gas, oxygen gas amount 20% by volume), and subsequently And heat treatment for 30 minutes in a reducing atmosphere at 450 ° C. (hydrogen gas and nitrogen gas mixed gas atmosphere, hydrogen gas amount 3 vol%). And it cooled to room temperature and obtained the metal film.

得られた金属被膜中に含まれる炭素原子の含有量を、炭素分析装置〔米国LECO社製のWR−112〕を使用して測定したところ、0.2重量%であった。また、酸素原子の含有量を、酸素分析装置〔米国LECO社製のTC−436〕を使用して測定し、その測定値と、銀−パラジウム合金微粒子の組成比から求められる、金属被膜中のパラジウムの含有量とから、金属被膜に含まれるパラジウムの総量中に占める、パラジウムの酸化物の含有量を求めたところ、1重量%であった。そして、これらの結果から、酸化性雰囲気中での熱処理と、還元性雰囲気中での熱処理とを順に行うことで、金属被膜中に含まれる、分散剤起源の炭素原子の量と、パラジウムの酸化物の量とを、共に低減できることが確認された。   It was 0.2 weight% when content of the carbon atom contained in the obtained metal coating film was measured using the carbon analyzer [WR-112 by the US LECO company]. Further, the oxygen atom content is measured using an oxygen analyzer [TC-436 manufactured by LECO, USA], and is obtained from the measured value and the composition ratio of the silver-palladium alloy fine particles. From the content of palladium, the content of palladium oxide in the total amount of palladium contained in the metal coating was determined and found to be 1% by weight. Based on these results, the amount of carbon atoms originating from the dispersant contained in the metal film and the oxidation of palladium can be determined by sequentially performing a heat treatment in an oxidizing atmosphere and a heat treatment in a reducing atmosphere. It was confirmed that both the amount of objects can be reduced.

次に、上記金属被膜の表面を、走査型電子顕微鏡を用いて観察したところ、図1に示すように、銀−パラジウム合金微粒子が緻密に焼結された、ボイドのない金属被膜が形成されていることが確認された。また、金属被膜の表面状態を、表面粗度計〔(株)東京精密製のサーフコム(登録商標)130A〕を用いて測定して、その測定結果から、前記算術平均高さRaを求めたところ10nmであって、金属被膜は、先に説明した基準に照らすと、緻密で表面が平滑であることが確認された。また、測定結果から、金属被膜の厚みを求めたところ0.2μmであった。   Next, when the surface of the metal film was observed using a scanning electron microscope, as shown in FIG. 1, a metal film having no voids, in which silver-palladium alloy fine particles were densely sintered, was formed. It was confirmed that Moreover, the surface state of the metal coating was measured using a surface roughness meter [Surfcom (registered trademark) 130A manufactured by Tokyo Seimitsu Co., Ltd.], and the arithmetic average height Ra was obtained from the measurement results. It was 10 nm, and the metal film was confirmed to be dense and smooth on the basis of the above-described criteria. Moreover, when the thickness of the metal film was calculated | required from the measurement result, it was 0.2 micrometer.

また、金属被膜の、基材表面への密着性を、日本工業規格JIS K 5600−5−6:1999「塗料一般試験方法−第5部:塗膜の機械的性質−第6節:付着性(クロスカット法)」に則って測定したところ、金属被膜のはがれは全く見られず、密着性が良好であることが判った。さらに、金属被膜の抵抗率を、抵抗率計〔三菱化学(株)製のロレスタ(登録商標)GP〕を用いて測定したところ、6μΩ・cmであって、金属被膜は、導電性にも優れることが確認された。   In addition, the adhesion of the metal coating to the surface of the base material was determined in accordance with Japanese Industrial Standard JIS K 5600-5-6: 1999 “Paint General Test Method—Part 5: Mechanical Properties of Coating—Section 6: Adhesiveness When measured in accordance with “Cross-cut method”, it was found that no peeling of the metal film was observed and adhesion was good. Furthermore, when the resistivity of the metal coating was measured using a resistivity meter [Loresta (registered trademark) GP manufactured by Mitsubishi Chemical Corporation], it was 6 μΩ · cm, and the metal coating was excellent in conductivity. It was confirmed.

実施例2:
金属微粒子分散液としては、液相還元法で製造された、一次粒子径が15nmである銀−パラジウム合金微粒子(パラジウム含量:5重量%)を、分散剤としてのポリアクリル酸(分子量5000)と共に、水とエタノールとの混合溶媒に分散して調製したものを用いた。そして、この金属微粒子分散液を、石英基板の表面に、スピンコート法によって塗布し、100℃で10分間、加熱して乾燥させて、厚み0.8μmの塗膜を形成した。
Example 2:
As the metal fine particle dispersion, silver-palladium alloy fine particles (palladium content: 5% by weight) produced by a liquid phase reduction method and having a primary particle diameter of 15 nm are combined with polyacrylic acid (molecular weight 5000) as a dispersant. A solution prepared by dispersing in a mixed solvent of water and ethanol was used. Then, this metal fine particle dispersion was applied to the surface of the quartz substrate by a spin coating method, and heated and dried at 100 ° C. for 10 minutes to form a coating film having a thickness of 0.8 μm.

次に、上記塗膜が形成された石英基板を、350℃の酸化性雰囲気(酸素ガスと窒素ガスの混合ガス雰囲気、酸素ガス量50体積%)中で30分間、熱処理した後、引き続いて、350℃の還元性雰囲気(水素ガスと窒素ガスの混合ガス雰囲気、水素ガス量10体積%)中で30分間、熱処理した。そして、室温に冷却して金属被膜を得た。   Next, the quartz substrate on which the coating film was formed was heat-treated for 30 minutes in an oxidizing atmosphere (mixed gas atmosphere of oxygen gas and nitrogen gas, oxygen gas amount 50 vol%) at 350 ° C. Heat treatment was performed in a reducing atmosphere at 350 ° C. (hydrogen gas and nitrogen gas mixed gas atmosphere, hydrogen gas amount 10% by volume) for 30 minutes. And it cooled to room temperature and obtained the metal film.

得られた金属被膜中に含まれる炭素原子の含有量を測定したところ、0.08重量%であった。また、酸素原子の含有量を測定して、金属被膜に含まれるパラジウムの総量中に占める、パラジウムの酸化物の含有量を求めたところ、0.05重量%であった。そして、これらの結果から、酸化性雰囲気中での熱処理と、還元性雰囲気中での熱処理とを順に行うことで、金属被膜中に含まれる、分散剤起源の炭素原子の量と、パラジウムの酸化物の量とを、共に低減できることが確認された。   It was 0.08 weight% when content of the carbon atom contained in the obtained metal film was measured. Further, the content of oxygen atoms was measured, and the content of palladium oxide in the total amount of palladium contained in the metal coating was determined. The result was 0.05% by weight. Based on these results, the amount of carbon atoms originating from the dispersant contained in the metal film and the oxidation of palladium can be determined by sequentially performing a heat treatment in an oxidizing atmosphere and a heat treatment in a reducing atmosphere. It was confirmed that both the amount of objects can be reduced.

次に、上記金属被膜の表面を、走査型電子顕微鏡を用いて観察したところ、実施例1と同様に、銀−パラジウム合金微粒子が緻密に焼結された、ボイドのない金属被膜が形成されていることが確認された。また、金属被膜の表面状態を測定して、その測定結果から、算術平均高さRaを求めたところ15nmであって、金属被膜は、先に説明した基準に照らすと、緻密で表面が平滑であることが確認された。また、金属被膜の厚みは0.5μmであった。また、金属被膜の、基材表面への密着性を、前記クロスカット法に則って評価したところ、金属被膜のはがれは全く見られず、密着性が良好であることが判った。さらに、金属被膜の抵抗率を測定したところ、3μΩ・cmであって、導電性にも優れることが確認された。   Next, when the surface of the metal film was observed using a scanning electron microscope, a void-free metal film in which silver-palladium alloy fine particles were densely sintered as in Example 1 was formed. It was confirmed that Further, the surface state of the metal film was measured, and the arithmetic average height Ra was determined from the measurement result. The metal film was 15 nm, and the metal film was dense and smooth on the basis of the above-described standard. It was confirmed that there was. The thickness of the metal coating was 0.5 μm. Further, when the adhesion of the metal coating to the substrate surface was evaluated according to the cross-cut method, it was found that no peeling of the metal coating was observed and the adhesion was good. Furthermore, when the resistivity of the metal coating was measured, it was 3 μΩ · cm, and it was confirmed that it was excellent in conductivity.

実施例3:
金属微粒子分散液としては、液相還元法で製造された、一次粒子径が50nmである銀−パラジウム−銅合金微粒子(パラジウム含量:0.9重量%、銅含量:1重量%)を、分散剤としてのポリビニルアルコール(分子量16000)と共に、水と2−プロパノールとの混合溶媒に分散して調製したものを用いた。そして、この金属微粒子分散液を、無アルカリガラス基板の表面に、スプレー法によって塗布し、100℃で10分間、加熱して乾燥させて、厚み2μmの塗膜を形成した。
Example 3:
As the metal fine particle dispersion, silver-palladium-copper alloy fine particles (palladium content: 0.9% by weight, copper content: 1% by weight) produced by a liquid phase reduction method and having a primary particle size of 50 nm are dispersed. What was prepared by dispersing in a mixed solvent of water and 2-propanol together with polyvinyl alcohol (molecular weight 16000) as an agent was used. And this metal fine particle dispersion was apply | coated to the surface of an alkali free glass substrate by the spray method, and it heated and dried at 100 degreeC for 10 minute (s), and formed the coating film with a thickness of 2 micrometers.

次に、上記塗膜が形成された無アルカリガラス基板を、250℃の酸化性雰囲気(酸素ガスと窒素ガスの混合ガス雰囲気、酸素ガス量20体積%)中で30分間、熱処理した後、引き続いて、450℃の還元性雰囲気(水素ガスとアルゴンガスの混合ガス雰囲気、水素ガス量3体積%)中で10分間、熱処理した。そして、室温に冷却して金属被膜を得た。   Next, the alkali-free glass substrate on which the coating film has been formed is heat-treated for 30 minutes in an oxidizing atmosphere (mixed gas atmosphere of oxygen gas and nitrogen gas, oxygen gas amount 20% by volume) at 250 ° C. Then, heat treatment was performed for 10 minutes in a reducing atmosphere at 450 ° C. (a mixed gas atmosphere of hydrogen gas and argon gas, a hydrogen gas amount of 3% by volume). And it cooled to room temperature and obtained the metal film.

得られた金属被膜中に含まれる炭素原子の含有量を測定したところ、0.1重量%であった。また、酸素原子の含有量を測定して、金属被膜に含まれるパラジウムおよび銅の総量中に占める、両金属元素の酸化物の含有量を求めたところ、2重量%であった。そして、これらの結果から、酸化性雰囲気中での熱処理と、還元性雰囲気中での熱処理とを順に行うことで、金属被膜中に含まれる、分散剤起源の炭素原子の量と、パラジウムおよび銅の酸化物の量とを、共に低減できることが確認された。   It was 0.1 weight% when content of the carbon atom contained in the obtained metal film was measured. Further, the content of oxygen atoms was measured, and the content of oxides of both metal elements in the total amount of palladium and copper contained in the metal coating was determined to be 2% by weight. From these results, by performing heat treatment in an oxidizing atmosphere and heat treatment in a reducing atmosphere in this order, the amount of carbon atoms originating from the dispersant contained in the metal film, palladium and copper It was confirmed that the amount of the oxide can be reduced together.

次に、上記金属被膜の表面を、走査型電子顕微鏡を用いて観察したところ、実施例1と同様に、銀−パラジウム−銅合金微粒子が緻密に焼結された、ボイドのない金属被膜が形成されていることが確認された。また、金属被膜の表面状態を測定して、その測定結果から、算術平均高さRaを求めたところ45nmであって、金属被膜は、先に説明した基準に照らすと、緻密で表面が平滑であることが確認された。また、金属被膜の厚みは1.5μmであった。また、金属被膜の、基材表面への密着性を、前記クロスカット法に則って評価したところ、金属被膜のはがれは全く見られず、密着性が良好であることが判った。さらに、金属被膜の抵抗率を測定したところ、6μΩ・cmであって、導電性にも優れることが確認された。   Next, when the surface of the metal film was observed using a scanning electron microscope, a void-free metal film was formed in which silver-palladium-copper alloy fine particles were densely sintered as in Example 1. It has been confirmed. Further, the surface state of the metal film was measured, and the arithmetic average height Ra was obtained from the measurement result. The metal film was 45 nm, and the metal film was dense and the surface was smooth according to the above-described criteria. It was confirmed that there was. The thickness of the metal coating was 1.5 μm. Further, when the adhesion of the metal coating to the substrate surface was evaluated according to the cross-cut method, it was found that no peeling of the metal coating was observed and the adhesion was good. Furthermore, when the resistivity of the metal coating was measured, it was 6 μΩ · cm, and it was confirmed that it was excellent in conductivity.

実施例4:
金属微粒子分散液としては、気相法で製造された、一次粒子径が100nmである銀−銅合金微粒子(銅含量:28重量%)を、分散剤としてのポリアクリル酸メチル(分子量40000)と共に、トルエンに分散して調製したものを用いた。そして、この金属微粒子分散液を、青板ガラス基板の表面に、ロールコート法によって塗布し、150℃で10分間、加熱して乾燥させて、厚み4μmの塗膜を形成した。
Example 4:
As the metal fine particle dispersion, silver-copper alloy fine particles (copper content: 28% by weight) produced by a vapor phase method and having a primary particle size of 100 nm are combined with polymethyl acrylate (molecular weight 40000) as a dispersant. The one prepared by dispersing in toluene was used. And this metal fine particle dispersion was apply | coated to the surface of a soda glass substrate by the roll coat method, and it heated and dried at 150 degreeC for 10 minute (s), and formed the coating film with a thickness of 4 micrometers.

次に、上記塗膜が形成された青板ガラス基板を、550℃の酸化性雰囲気(酸素ガスと窒素ガスの混合ガス雰囲気、酸素ガス量10体積%)中で15分間、熱処理した後、引き続いて、550℃の還元性雰囲気(水素ガスとアルゴンガスの混合ガス雰囲気、水素ガス量20体積%)中で30分間、熱処理した。そして、室温に冷却して金属被膜を得た。   Next, the soda-lime glass substrate on which the coating film is formed is heat-treated for 15 minutes in an 550 ° C. oxidizing atmosphere (mixed gas atmosphere of oxygen gas and nitrogen gas, oxygen gas amount 10% by volume), and subsequently Heat treatment was performed for 30 minutes in a reducing atmosphere at 550 ° C. (hydrogen gas and argon gas mixed gas atmosphere, hydrogen gas amount 20% by volume). And it cooled to room temperature and obtained the metal film.

得られた金属被膜中に含まれる炭素原子の含有量を測定したところ、0.5重量%であった。また、酸素原子の含有量を測定して、金属被膜に含まれる銅の総量中に占める、銅の酸化物の含有量を求めたところ、0.1重量%であった。そして、これらの結果から、酸化性雰囲気中での熱処理と、還元性雰囲気中での熱処理とを順に行うことで、金属被膜中に含まれる、分散剤起源の炭素原子の量と、銅の酸化物の量とを、共に低減できることが確認された。   It was 0.5 weight% when content of the carbon atom contained in the obtained metal film was measured. Further, the content of oxygen atom was measured to determine the content of copper oxide in the total amount of copper contained in the metal coating, and it was 0.1% by weight. Based on these results, the amount of carbon atoms originating from the dispersant contained in the metal coating and the oxidation of copper can be determined by sequentially performing a heat treatment in an oxidizing atmosphere and a heat treatment in a reducing atmosphere. It was confirmed that both the amount of objects can be reduced.

次に、上記金属被膜の表面を、走査型電子顕微鏡を用いて観察したところ、実施例1と同様に、銀−銅合金微粒子が緻密に焼結された、ボイドのない金属被膜が形成されていることが確認された。また、金属被膜の表面状態を測定して、その測定結果から、算術平均高さRaを求めたところ150nmであって、金属被膜は、先に説明した基準に照らすと、緻密で表面が平滑であることが確認された。また、金属被膜の厚みは2μmであった。また、金属被膜の、基材表面への密着性を、前記クロスカット法に則って評価したところ、金属被膜のはがれは全く見られず、密着性が良好であることが判った。さらに、金属被膜の抵抗率を測定したところ、4μΩ・cmであって、導電性にも優れることが確認された。   Next, when the surface of the metal film was observed using a scanning electron microscope, a void-free metal film was formed in which silver-copper alloy fine particles were densely sintered as in Example 1. It was confirmed that Further, the surface state of the metal film was measured, and the arithmetic average height Ra was obtained from the measurement result. It was 150 nm, and the metal film was dense and smooth on the basis of the above-described standard. It was confirmed that there was. The thickness of the metal coating was 2 μm. Further, when the adhesion of the metal coating to the substrate surface was evaluated according to the cross-cut method, it was found that no peeling of the metal coating was observed and the adhesion was good. Furthermore, when the resistivity of the metal film was measured, it was 4 μΩ · cm, and it was confirmed that it was excellent in conductivity.

実施例5:
金属微粒子分散液としては、液相還元法で製造された、一次粒子径が5nmである金−スズ合金微粒子(スズ含量:20重量%)を、分散剤としてのポリビニルピロリドン(分子量30000)と共に、水に分散して調製したものを用いた。そして、この金属微粒子分散液を、ポリイミド基板の表面に、ディップコート法によって塗布し、100℃で10分間、加熱して乾燥させて、厚み0.15μmの塗膜を形成した。
Example 5:
As the metal fine particle dispersion, gold-tin alloy fine particles (tin content: 20% by weight) produced by a liquid phase reduction method and having a primary particle diameter of 5 nm, together with polyvinylpyrrolidone (molecular weight 30000) as a dispersant, What was prepared by dispersing in water was used. And this metal fine particle dispersion was apply | coated to the surface of a polyimide substrate by the dip coating method, and it heated and dried at 100 degreeC for 10 minute (s), and formed the coating film with a thickness of 0.15 micrometer.

次に、上記塗膜が形成されたポリイミド基板を、200℃の酸化性雰囲気(酸素ガスとアルゴンガスの混合ガス雰囲気、酸素ガス量20体積%)中で120分間、熱処理した後、引き続いて、200℃の還元性雰囲気(水素ガスとヘリウムガスの混合ガス雰囲気、水素ガス量3体積%)中で120分間、熱処理した。そして、室温に冷却して金属被膜を得た。   Next, after heat-treating the polyimide substrate on which the coating film is formed in an oxidizing atmosphere at 200 ° C. (mixed gas atmosphere of oxygen gas and argon gas, oxygen gas amount 20% by volume) for 120 minutes, Heat treatment was performed for 120 minutes in a reducing atmosphere at 200 ° C. (mixed gas atmosphere of hydrogen gas and helium gas, 3% by volume of hydrogen gas). And it cooled to room temperature and obtained the metal film.

得られた金属被膜中に含まれる炭素原子の含有量を測定したところ、0.5重量%であった。また、酸素原子の含有量を測定して、金属被膜に含まれるスズの総量中に占める、スズの酸化物の含有量を求めたところ、0.2重量%であった。そして、これらの結果から、酸化性雰囲気中での熱処理と、還元性雰囲気中での熱処理とを順に行うことで、金属被膜中に含まれる、分散剤起源の炭素原子の量と、スズの酸化物の量とを、共に低減できることが確認された。   It was 0.5 weight% when content of the carbon atom contained in the obtained metal film was measured. Further, the content of oxygen atoms was measured, and the content of tin oxide in the total amount of tin contained in the metal coating was determined. The result was 0.2% by weight. From these results, the amount of carbon atoms originating from the dispersant contained in the metal film and the oxidation of tin are sequentially performed by heat treatment in an oxidizing atmosphere and heat treatment in a reducing atmosphere. It was confirmed that both the amount of objects can be reduced.

次に、上記金属被膜の表面を、走査型電子顕微鏡を用いて観察したところ、実施例1と同様に、金−スズ合金微粒子が緻密に焼結された、ボイドのない金属被膜が形成されていることが確認された。また、金属被膜の表面状態を測定して、その測定結果から、算術平均高さRaを求めたところ5nmであって、金属被膜は、先に説明した基準に照らすと、緻密で表面が平滑であることが確認された。また、金属被膜の厚みは0.1μmであった。また、金属被膜の、基材表面への密着性を、前記クロスカット法に則って評価したところ、金属被膜のはがれは全く見られず、密着性が良好であることが判った。さらに、金属被膜の抵抗率を測定したところ、10μΩ・cmであって、導電性にも優れることが確認された。   Next, when the surface of the metal film was observed using a scanning electron microscope, a void-free metal film in which gold-tin alloy fine particles were densely sintered as in Example 1 was formed. It was confirmed that Further, the surface state of the metal coating was measured, and the arithmetic average height Ra was obtained from the measurement result. The metal coating was 5 nm, and the metal coating was dense and the surface was smooth according to the above-described criteria. It was confirmed that there was. The thickness of the metal coating was 0.1 μm. Further, when the adhesion of the metal coating to the substrate surface was evaluated according to the cross-cut method, it was found that no peeling of the metal coating was observed and the adhesion was good. Furthermore, when the resistivity of the metal coating was measured, it was 10 μΩ · cm, and it was confirmed that the conductivity was excellent.

実施例6:
金属微粒子分散液としては、気相法で製造された、一次粒子径が150nmである銀−金−スズ合金微粒子(金含量:1.7重量%、スズ含量:2重量%)を、分散剤としてのオレイン酸アミド(分子量281)と共に、テトラデカンに分散して調製したものを用いた。そして、この金属微粒子分散液を、耐熱ガラス基板の表面に、スピンコート法によって塗布し、200℃で10分間、加熱して乾燥させて、厚み1.2μmの塗膜を形成した。
Example 6:
As the metal fine particle dispersion, silver-gold-tin alloy fine particles (gold content: 1.7 wt%, tin content: 2 wt%) produced by a gas phase method and having a primary particle diameter of 150 nm are used as a dispersant. And oleic acid amide (molecular weight 281) as a dispersion prepared in tetradecane. And this metal fine particle dispersion was apply | coated to the surface of a heat-resistant glass substrate by the spin coat method, and it heated and dried at 200 degreeC for 10 minute (s), and formed the coating film with a thickness of 1.2 micrometers.

次に、上記塗膜が形成された耐熱ガラス基板を、450℃の酸化性雰囲気(酸素ガスと窒素ガスの混合ガス雰囲気、酸素ガス量50体積%)中で30分間、熱処理した後、引き続いて、450℃の還元性雰囲気(アンモニアガス雰囲気)中で15分間、熱処理した。そして、室温に冷却して金属被膜を得た。   Next, the heat-resistant glass substrate on which the coating film has been formed is heat-treated for 30 minutes in an oxidizing atmosphere at 450 ° C. (oxygen gas and nitrogen gas mixed gas atmosphere, oxygen gas amount 50% by volume), and then And heat treatment in a reducing atmosphere (ammonia gas atmosphere) at 450 ° C. for 15 minutes. And it cooled to room temperature and obtained the metal film.

得られた金属被膜中に含まれる炭素原子の含有量を測定したところ、0.05重量%であった。また、酸素原子の含有量を測定して、金属被膜に含まれるスズの総量中に占める、スズの酸化物の含有量を求めたところ、0.02重量%であった。そして、これらの結果から、酸化性雰囲気中での熱処理と、還元性雰囲気中での熱処理とを順に行うことで、金属被膜中に含まれる、分散剤起源の炭素原子の量と、スズの酸化物の量とを、共に低減できることが確認された。   It was 0.05 weight% when content of the carbon atom contained in the obtained metal coating film was measured. Further, the content of oxygen atoms was measured, and the content of tin oxide in the total amount of tin contained in the metal coating was determined to be 0.02% by weight. From these results, the amount of carbon atoms originating from the dispersant contained in the metal film and the oxidation of tin are sequentially performed by heat treatment in an oxidizing atmosphere and heat treatment in a reducing atmosphere. It was confirmed that both the amount of objects can be reduced.

次に、上記金属被膜の表面を、走査型電子顕微鏡を用いて観察したところ、実施例1と同様に、銀−金−スズ合金微粒子が緻密に焼結された、ボイドのない金属被膜が形成されていることが確認された。また、金属被膜の表面状態を測定して、その測定結果から、算術平均高さRaを求めたところ180nmであって、金属被膜は、先に説明した基準に照らすと、緻密で表面が平滑であることが確認された。また、金属被膜の厚みは1μmであった。また、金属被膜の、基材表面への密着性を、前記クロスカット法に則って評価したところ、金属被膜のはがれは全く見られず、密着性が良好であることが判った。さらに、金属被膜の抵抗率を測定したところ、5μΩ・cmであって、導電性にも優れることが確認された。   Next, when the surface of the metal coating was observed using a scanning electron microscope, a void-free metal coating was formed in which silver-gold-tin alloy fine particles were densely sintered as in Example 1. It has been confirmed. Further, the surface state of the metal film was measured, and the arithmetic average height Ra was obtained from the measurement result. The result was 180 nm, and the metal film was dense and smooth on the surface described above. It was confirmed that there was. The thickness of the metal coating was 1 μm. Further, when the adhesion of the metal coating to the substrate surface was evaluated according to the cross-cut method, it was found that no peeling of the metal coating was observed and the adhesion was good. Furthermore, when the resistivity of the metal film was measured, it was 5 μΩ · cm, and it was confirmed that it was excellent in conductivity.

比較例1:
実施例1で作製したのと同じ塗膜が形成された青板ガラス基板を、400℃の酸化性雰囲気(酸素ガスと窒素ガスの混合ガス雰囲気、酸素ガス量20体積%)中で30分間、熱処理する操作を2回、繰り返して行い、還元性雰囲気中での熱処理を省略したこと以外は、実施例1と同様にして金属被膜を得た。
Comparative Example 1:
A soda-lime glass substrate on which the same coating film as prepared in Example 1 was formed was heat-treated in an oxidizing atmosphere at 400 ° C. (mixed gas atmosphere of oxygen gas and nitrogen gas, oxygen gas amount 20% by volume) for 30 minutes. The metal film was obtained in the same manner as in Example 1 except that the operation was repeated twice and the heat treatment in a reducing atmosphere was omitted.

得られた金属被膜中に含まれる炭素原子の含有量を測定したところ、0.2重量%であった。また、酸素原子の含有量を測定して、金属被膜に含まれるパラジウムの総量中に占める、パラジウムの酸化物の含有量を求めたところ、8重量%であった。そして、これらの結果から、酸化性雰囲気中での熱処理を行うことで、金属被膜中に含まれる、分散剤起源の炭素原子の量を低減できるものの、還元性雰囲気中での熱処理を行わなかったため、パラジウムの酸化物の量を低減できないことが確認された。   When the content of carbon atoms contained in the obtained metal coating was measured, it was 0.2% by weight. Further, the content of oxygen atoms was measured, and the content of palladium oxide in the total amount of palladium contained in the metal coating was determined. The content was 8% by weight. And from these results, the amount of carbon atoms originating from the dispersant contained in the metal coating can be reduced by performing the heat treatment in an oxidizing atmosphere, but the heat treatment was not performed in a reducing atmosphere. It was confirmed that the amount of palladium oxide could not be reduced.

次に、上記金属被膜の表面を、走査型電子顕微鏡を用いて観察したところ、図2に示すように、多数の、粗大なボイドを有するものとなってしまい、緻密な金属被膜が形成されていないことが確認された。また、金属被膜の表面状態を測定して、その測定結果から、算術平均高さRaを求めたところ45nmであって、金属被膜は、先に説明した基準に照らすと、緻密でも平滑でもない荒れた膜であることが確認された。また、金属被膜の厚みは0.2μmであった。また、金属被膜の、基材表面への密着性を、前記クロスカット法に則って評価したところ、金属被膜のはがれは全く見られず、密着性が良好であることが判った。さらに、金属被膜の抵抗率を測定したところ、10μΩ・cmであって、導電性が低いことが確認された。   Next, when the surface of the metal film was observed using a scanning electron microscope, as shown in FIG. 2, it had a large number of coarse voids, and a dense metal film was formed. Not confirmed. Further, the surface state of the metal film was measured, and the arithmetic average height Ra was obtained from the measurement result. The result was 45 nm, and the metal film was rough and neither smooth nor smooth according to the above-described criteria. It was confirmed that the film was a thin film. The thickness of the metal coating was 0.2 μm. Further, when the adhesion of the metal coating to the substrate surface was evaluated according to the cross-cut method, it was found that no peeling of the metal coating was observed and the adhesion was good. Furthermore, when the resistivity of the metal film was measured, it was 10 μΩ · cm, and it was confirmed that the conductivity was low.

比較例2:
実施例1で作製したのと同じ塗膜が形成された青板ガラス基板を、400℃の不活性雰囲気(窒素ガス雰囲気)中で30分間、熱処理した後、引き続いて、450℃の還元性雰囲気(水素ガスと窒素ガスの混合ガス雰囲気、水素ガス量3体積%)中で30分間、熱処理したこと以外は、実施例1と同様にして金属被膜を得た。
Comparative Example 2:
The soda-lime glass substrate on which the same coating film as that prepared in Example 1 was formed was heat-treated in an inert atmosphere (nitrogen gas atmosphere) at 400 ° C. for 30 minutes, and subsequently, a reducing atmosphere at 450 ° C. ( A metal film was obtained in the same manner as in Example 1 except that the heat treatment was performed for 30 minutes in a mixed gas atmosphere of hydrogen gas and nitrogen gas, and 3% by volume of hydrogen gas.

得られた金属被膜中に含まれる炭素原子の含有量を測定したところ、4重量%であった。また、酸素原子の含有量を測定して、金属被膜に含まれるパラジウムの総量中に占める、パラジウムの酸化物の含有量を求めたところ、0.01重量%であった。そして、これらの結果から、不活性雰囲気中での熱処理では、分散剤起源の炭素原子の量を十分に低減できないことが確認された。   It was 4 weight% when content of the carbon atom contained in the obtained metal film was measured. Further, the content of oxygen atoms was measured to determine the content of palladium oxide in the total amount of palladium contained in the metal coating. The content was 0.01% by weight. From these results, it was confirmed that the amount of carbon atoms originating from the dispersant cannot be sufficiently reduced by heat treatment in an inert atmosphere.

次に、上記金属被膜の表面を、走査型電子顕微鏡を用いて観察したところ、実施例1と同様に緻密であるものの、わずかにボイドのある金属被膜が形成されていることが確認された。また、金属被膜の表面状態を測定して、その測定結果から、算術平均高さRaを求めたところ20nmであって、金属被膜は、先に説明した基準に照らすと、緻密で表面が平滑であることが確認された。また、金属被膜の厚みは0.2μmであった。また、金属被膜の、基材表面への密着性を、前記クロスカット法に則って評価したところ、試験した全面で金属被膜がはがれてしまい、密着性が不良であることが判った。さらに、金属被膜の抵抗率を測定したところ、15μΩ・cmであって、導電性が低いことが確認された。   Next, when the surface of the metal film was observed using a scanning electron microscope, it was confirmed that a metal film with a slight void was formed although it was dense as in Example 1. Further, the surface state of the metal film was measured, and the arithmetic average height Ra was obtained from the measurement result. The metal film was 20 nm, and the metal film was dense and smooth in terms of the above-described criteria. It was confirmed that there was. The thickness of the metal coating was 0.2 μm. Further, when the adhesion of the metal coating to the substrate surface was evaluated according to the cross-cut method, it was found that the metal coating peeled off on the entire surface tested and the adhesion was poor. Furthermore, when the resistivity of the metal film was measured, it was 15 μΩ · cm, and it was confirmed that the conductivity was low.

本発明の、実施例1で形成した金属被膜の一部を拡大した走査型電子顕微鏡写真である。It is the scanning electron micrograph which expanded a part of metal coating film formed in Example 1 of this invention. 比較例1で形成した金属被膜の一部を拡大した走査型電子顕微鏡写真である。2 is a scanning electron micrograph in which a part of the metal coating formed in Comparative Example 1 is enlarged.

Claims (6)

基材の表面に、金属微粒子分散液を印刷または塗布し、乾燥させて形成した塗膜を熱処理して形成される金属被膜であって、金属微粒子分散液は、金属微粒子と、炭素原子を含む分散剤とを含み、金属微粒子は、当該金属微粒子を形成する金属元素と、当該金属元素より酸化性の高い酸化性金属元素の少なくとも1種との合金または複合体であり、金属被膜中に含まれる炭素原子の含有量が1重量%以下で、かつ、金属被膜中に含まれる酸化性金属元素の総量中に占める、当該酸化性金属元素の酸化物の含有量が5重量%以下であることを特徴とする金属被膜。   A metal film formed by printing or applying a metal fine particle dispersion on the surface of a substrate and drying it to heat-treat the metal fine particle dispersion, the metal fine particle dispersion containing metal fine particles and carbon atoms And a metal fine particle is an alloy or a composite of a metal element forming the metal fine particle and at least one oxidizing metal element that is more oxidizable than the metal element, and is included in the metal film. The content of carbon atoms to be contained is 1% by weight or less, and the content of oxides of the oxidizing metal elements in the total amount of oxidizing metal elements contained in the metal coating is 5% by weight or less. A metal coating characterized by 酸化性金属元素を30重量%以下の割合で含有する合金または複合体からなる金属微粒子を用いて形成される請求項1記載の金属被膜。   2. The metal coating according to claim 1, wherein the metal coating is formed using metal fine particles comprising an alloy or a composite containing an oxidizing metal element in a proportion of 30% by weight or less. 銀および金のうちの少なくとも一方と、酸化性金属元素としての、パラジウム、銅、スズ、ニッケルおよびコバルトからなる群より選ばれた少なくとも1種との合金または複合体からなる金属微粒子を用いて形成される請求項1記載の金属被膜。   Formed using metal fine particles made of an alloy or composite of at least one of silver and gold and at least one selected from the group consisting of palladium, copper, tin, nickel and cobalt as an oxidizing metal element The metal coating according to claim 1. 請求項1記載の金属被膜を形成する方法であって、基材の表面に、金属元素と、当該金属元素より酸化性の高い酸化性金属元素の少なくとも1種との合金または複合体からなる金属微粒子と、炭素原子を含む分散剤とを含む金属微粒子分散液を印刷または塗布し、乾燥させて塗膜を形成する工程と、形成した塗膜を、まず、酸化性雰囲気中で熱処理した後、還元性雰囲気中で再度、熱処理する工程とを含むことを特徴とする金属被膜の形成方法。   2. A method for forming a metal coating according to claim 1, wherein a metal comprising an alloy or a composite of a metal element and at least one oxidizing metal element having a higher oxidizing property than the metal element is formed on the surface of the substrate. A step of printing or applying a fine metal particle dispersion containing fine particles and a carbon atom-containing dispersant and drying to form a coating film, and after the formed coating film is first heat-treated in an oxidizing atmosphere, And a heat treatment process again in a reducing atmosphere. 酸化性雰囲気中での熱処理を、150℃以上の温度で行う請求項4記載の金属被膜の形成方法。   The method for forming a metal film according to claim 4, wherein the heat treatment in an oxidizing atmosphere is performed at a temperature of 150 ° C or higher. 還元性雰囲気中での熱処理を、150℃以上の温度で行う請求項4記載の金属被膜の形成方法。

The method for forming a metal film according to claim 4, wherein the heat treatment in a reducing atmosphere is performed at a temperature of 150 ° C or higher.

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JP2007200659A (en) * 2006-01-25 2007-08-09 Nippon Shokubai Co Ltd Method of manufacturing metal film
JP2007324025A (en) * 2006-06-02 2007-12-13 Nippon Shokubai Co Ltd Metal coat
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JPH10294018A (en) * 1997-04-16 1998-11-04 Ulvac Japan Ltd Burning method for metal paste
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Publication number Priority date Publication date Assignee Title
JP2007200659A (en) * 2006-01-25 2007-08-09 Nippon Shokubai Co Ltd Method of manufacturing metal film
JP2007324025A (en) * 2006-06-02 2007-12-13 Nippon Shokubai Co Ltd Metal coat
JP2015166084A (en) * 2008-08-22 2015-09-24 日産化学工業株式会社 Metal fine particle dispersant comprising branched polymer compound having ammonium group
KR101195911B1 (en) * 2010-09-17 2012-10-30 서강대학교산학협력단 Spherical porous structure and producing method of the same

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