JP7566488B2 - Conductive compositions and metallized substrates and methods for their manufacture - Google Patents

Description

The present invention relates to a conductive composition used in the electronics field to form circuits on ceramic substrates, a metallized substrate having circuits formed from this composition, and a method for producing the same.

Conductive compositions (conductive pastes) are widely used in the electronics field because they can be easily used to form various patterns such as electrodes by printing. Silver pastes, which contain silver in conductive metal powder, are used to form electrodes and circuits for electronic components, and are broadly divided into resin-cured and sintered types.

In resin-cured conductive compositions, the metal comes into contact with the resin as it hardens, ensuring electrical conductivity. On the other hand, in sintered conductive compositions, the metal particles bond together as a result of sintering, ensuring electrical conductivity.

Baked-type conductive compositions contain conductive metal powders such as silver, copper, nickel, palladium, and gold, as well as glass powder as an inorganic binder, a vehicle, a solvent, etc. Conductive compositions are required to meet requirements such as adhesion to substrates, plating resistance, solder resistance, reliability, and electromigration resistance.

Plating is performed to prevent solder erosion of the electrodes, to prevent sulfurization, and to protect against corrosion. If the fired film is porous, plating solution may penetrate during plating, which may reduce the adhesive strength with the substrate. In addition, the infiltrated plating solution may evaporate and expand due to reflow, causing the electrodes to burst, resulting in reduced reliability. Therefore, a dense film must be formed to ensure plating resistance.

Silver (Ag) is stable in air and can be fired in air, but has the disadvantage of being prone to electromigration. Conductive pastes containing metal compounds such as Cu, Mn, and Sn have been disclosed to prevent Ag electromigration and to improve solder resistance.

JP 55-149356 A (Patent Document 1) discloses a conductive paint that prevents migration by mixing 100 parts by mass of Ag powder with 1 to 100 parts by mass of Mn and/or Mn alloy powder.

JP 2003-115216 A (Patent Document 2) discloses a conductive paste containing a binder resin, Ag powder, and at least one metal or metal compound selected from the group consisting of Ti, Ni, In, Sn, and Sb.

However, the paint in Patent Document 1 and the paste in Patent Document 2 have not been evaluated for adhesion, solder heat resistance, plating resistance, reliability, etc.

WO2014/061765 (Patent Document 3) discloses a conductive paste containing Ag powder, glass frit, an organic binder, and powder containing Cu, Sn, and Mn, and describes that the paste has excellent electromigration resistance, solder heat resistance, and adhesion.

However, this paste has not been evaluated for plating resistance or reliability.

WO2015/141816 (Patent Document 4) discloses a conductive paste containing Ag powder, glass frit, an organic binder, and a powder containing Cu element and at least one metal element selected from the group consisting of V, Cr, Mn, Fe, and Co. This document describes that the inclusion of the metal powder improves the electromigration resistance, solder heat resistance, and adhesion of the conductive paste.

However, even this paste has not been evaluated for its resistance to plating.

WO2017/141984 (Patent Document 5) discloses a conductive paste containing Ag powder, glass frit, an organic binder, and Pt-group oxides such as Cu, Sn, Mn, and ruthenium oxide. In this document, reliability tests such as high-temperature exposure and heat cycles are carried out.

However, even this paste has not been evaluated for its resistance to plating.

JP 2018-152218 A (Patent Document 6) discloses a conductive paste containing Ag powder, Bi-based glass powder, a silsesquioxane compound, and an organic vehicle. This document describes evaluations of plating resistance and solder resistance.

However, this paste has not been evaluated for reliability.

JP-A-55-149356 (Claims, page 2, upper right column, line 1) JP 2003-115216 A (Claim 1) WO2014/061765 (Claim 1, paragraph [0025]) WO2015/141816 (Claim 1, paragraphs [0009] [0010]) WO2017/141984 (Claims, Examples) JP 2018-152218 A (Claim 1, paragraph [0009])

The object of the present invention is therefore to provide a conductive composition capable of forming a conductive part with high adhesion to a ceramic substrate and capable of producing a metallized substrate with high plating resistance and reliability, a metallized substrate having a conductive part formed from this composition, and a method for producing the same.

Another object of the present invention is to provide a conductive composition capable of forming a conductive part with high adhesion to a ceramic substrate regardless of changes in the usage environment, a metallized substrate having a conductive part formed from this composition, and a method for manufacturing the same.

As a result of intensive research into achieving the above-mentioned object, the inventors discovered that by combining Ag particles (A) consisting of isotropic small Ag particles (A1) with a particle size of less than 1.2 μm and isotropic large Ag particles (A2) with a particle size of 1.2 μm or more, metal components (B) consisting of Mn components (B1), Fe components (B2) and Cu components (B3), and glass particles (C), it is possible to form a conductive portion with high adhesion to a ceramic substrate, and to manufacture a metallized substrate with high plating resistance and reliability, thereby completing the present invention.

That is, the conductive composition of the present invention is a conductive composition containing Ag particles (A), metal components (B) and glass particles (C), the Ag particles (A) being small Ag particles (A1) and large Ag particles (A2), the Ag small particles (A1) being isotropically shaped particles with a particle size of less than 1.2 μm, and the Ag large particles (A2) being isotropically shaped particles with a particle size of 1.2 μm or more, and the metal components (B) being Mn components (B1), Fe components (B2) and Cu components (B3). The Ag small particles (A1) may be spherical particles with a median particle size of 0.01 μm or more and less than 1.2 μm. The Ag large particles (A2) may be spherical particles with a median particle size of 1.2 to 20 μm. The mass ratio of the Ag small particles (A1) to the Ag large particles (A2) is about 90/10 to 5/95. The glass particles (C) may contain bismuth-based glass particles and/or zinc-based glass particles.

The present invention also includes a method for producing the conductive composition, in which at least one selected from the group consisting of the Mn component (B1), the Fe component (B2), and the Cu component (B3) is added in the form of a liquid composition.

The present invention also includes a method for manufacturing a metallized substrate, which includes an attachment step of attaching the conductive composition to a ceramic substrate, and a firing step of firing the conductive composition attached to the ceramic substrate to form a conductive portion. In the firing step, the conductive composition may be fired in air.

The present invention also includes a metallized substrate obtained by the above manufacturing method. The ceramic substrate may be an alumina substrate, an alumina-zirconia substrate, an aluminum nitride substrate, a silicon nitride substrate, or a silicon carbide substrate.

In this application, the term "metal component" is used to include both simple metals and metal compounds. The same applies to Mn components, Fe components, and Cu components.

In the present invention, Ag particles (A) consisting of isotropic Ag small particles (A1) with a particle size of less than 1.2 μm and isotropic Ag large particles (A2) with a particle size of 1.2 μm or more are combined with metal components (B) consisting of Mn components (B1), Fe components (B2) and Cu components (B3) and glass particles (C), so that a conductive part with high adhesion to a ceramic substrate can be formed and a metallized substrate with high plating resistance and reliability can be manufactured. In particular, a conductive part with high adhesion to a ceramic substrate can be formed regardless of changes in the usage environment. Furthermore, it shows excellent conductivity and electromigration resistance, and can maintain high adhesion to a ceramic substrate even under harsh conditions such as high temperature and high humidity, sudden temperature changes, and long-term exposure to high temperatures, so that a highly reliable metallized substrate can be manufactured.

[Ag particles (A)]
The conductive composition of the present invention contains Ag particles (A) as a conductive component. The Ag particles (A) are a combination of isotropic small Ag particles (A1) having a particle size of less than 1.2 μm and isotropic large Ag particles (A2) having a particle size of 1.2 μm or more. The Ag particles (A) impart conductivity, and by combining the Ag small particles (A1) and the Ag large particles (A2), the Ag particles can form a close-packed structure, thereby forming a denser film.

(Ag small particles (A1))
The shape of the Ag small particles (A1) is an isotropic shape in terms of improving plating resistance and reliability. Examples of the isotropic shape include a spherical shape (true spherical or nearly spherical), a regular polyhedral shape (regular Among these, the spherical shape is particularly preferred in terms of improving the adhesion to the ceramic substrate.

In this application, the term "spherical" is used to include both a perfect sphere and an approximately spherical shape. In a sphere, the ratio of the major axis to the minor axis is, for example, 1 to 2, preferably 1 to 1.5, more preferably 1 to 1.3, even more preferably 1 to 1.2, and most preferably 1 to 1.1. In addition, an isotropic shape also includes an approximately isotropic shape.

The particle size (particle size distribution) of the small Ag particles (A1) may be in the range of less than 1.2 μm, for example, in the range of 0.01 μm or more and less than 1.2 μm. The median particle size (D50) of the small Ag particles (A1) is, for example, 0.05 μm or more and less than 1.2 μm, preferably 0.1 to 1 μm, more preferably 0.2 to 0.8 μm, more preferably 0.3 to 0.7 μm, more preferably 0.4 to 0.6 μm, and most preferably about 0.45 to 0.55 μm. If the particle size of the small Ag particles (A1) is too small, it may be difficult to fill the gaps between the large Ag particles (A2), and conversely, if it is too large, it may be difficult for the small Ag particles to penetrate into the gaps.

The 10 volume % particle size (D10) of the small Ag particles (A1) may be 0.01 μm or more (e.g., 0.01 to 0.49 μm), for example, 0.1 μm or more (e.g., 0.1 to 0.45 μm), preferably 0.2 μm or more, more preferably 0.3 μm or more, and most preferably 0.4 μm or more (e.g., 0.4 to 0.43 μm). If D10 is too small, it may be difficult to efficiently fill the gaps between the large Ag particles (A2).

The 90 volume percent particle size (D90) of the small Ag particles (A1) may be 1.19 μm or less (e.g., 0.5 to 1.19 μm), for example, 1.18 μm or less, preferably 1.17 μm or less, more preferably 1.15 μm or less, and most preferably 1.12 μm or less (e.g., 1 to 1.12 μm). If D90 is too large, it may be difficult to efficiently fill the gaps between the large Ag particles (A2).

In this application, the particle size distribution and median particle size of particles (including other particles described below) refer to the particle size distribution and median particle size (volume basis) measured using a laser diffraction scattering type particle size distribution measuring device.

(Ag large particles (A2))
The shape of the large Ag particles (A2) is also isotropic from the viewpoint of improving plating resistance and reliability, and is the same as that of the small Ag particles (A1), including the preferred embodiments.

The particle size (particle size distribution) of the large Ag particles (A2) may be in the range of 1.2 μm or more, for example, 1.2 to 20 μm, preferably 1.2 to 15 μm, more preferably 1.2 to 10 μm, and most preferably about 1.2 to 8 μm. The median particle size (D50) of the large Ag particles (A2) is, for example, 1.2 to 20 μm, preferably 1.3 to 10 μm, more preferably 1.5 to 5 μm, more preferably 1.7 to 3 μm, more preferably 1.8 to 2.5 μm, and most preferably about 1.9 to 2.2 μm. If the particle size of the large Ag particles (A2) is too small, there is a risk that the adhesion to the ceramic substrate will decrease, and conversely, if the particle size is too large, there is a risk that the adhesion will also decrease.

The 10 volume percent particle size (D10) of the large Ag particles (A2) may be 1.21 μm or more (e.g., 1.21 to 1.9 μm), for example, 1.22 μm or more (e.g., 1.22 to 1.8 μm), preferably 1.23 μm or more, more preferably 1.24 μm or more, and most preferably 1.25 μm or more (e.g., 1.25 to 1.5 μm). If D10 is too small, there is a risk of reduced adhesion to the ceramic substrate.

The 90 volume percent particle size (D90) of the large Ag particles (A2) may be 10 μm or less (e.g., 2 to 10 μm), for example, 8 μm or less, preferably 5 μm or less, more preferably 3.5 μm or less, and most preferably 3.3 μm or less (e.g., 2.5 to 3.3 μm). If D90 is too large, there is a risk of reduced adhesion to the ceramic substrate.

(Characteristics of Ag particles (A))
The mass ratio of the Ag small particles (A1) to the Ag large particles (A2) can be selected from the range of about the former/latter = 99/1 to 1/99 (e.g., 95/5 to 10/90), for example, 90/10 to 5/95 (e.g., 90/10 to 10/90), preferably 90/10 to 20/80 (e.g., 80/20 to 10/90), more preferably 70/30 to 20/80, and most preferably about 50/50 to 30/70. If the proportion of the Ag small particles (A1) is too small, the denseness of the fired body may decrease, and conversely, if it is too large, the adhesion to the ceramic substrate may decrease.

The median particle size (D50) of the Ag particles (A) is, for example, 0.1 to 10 μm, preferably 0.3 to 5 μm, more preferably 0.5 to 3 μm, and most preferably about 1 to 2 μm. If the particle size of the Ag particles (A) is too small, there is a risk that the adhesion to the ceramic substrate will decrease, and conversely, if the particle size is too large, there is a similar risk that the adhesion will decrease.

The proportion of Ag particles (A) in the conductive composition can be selected from a range of about 10 to 99 mass%, for example about 30 to 98 mass%, preferably 50 to 95 mass%, more preferably 70 to 93 mass%, and most preferably about 80 to 90 mass%. If the proportion of Ag particles (A) is too low, there is a risk of reduced conductivity, and conversely, if it is too high, there is a risk of reduced adhesion to the ceramic substrate.

[Metal component (B)]
The metal component (B) is a combination of a Mn component (B1), an Fe component (B2), and a Cu component (B3). In the present invention, the conductive composition contains the metal component (B), which can improve the denseness and electromigration resistance of the sintered body, and can improve the reliability of the conductive part of the sintered body. Furthermore, it is preferable that at least one of the Mn component (B1), the Fe component (B2), and the Cu component (B3) is an organometallic compound (particularly, a metal carboxylate) in terms of ease of viscosity adjustment during composition preparation and improved reliability.

(Mn component (B1))
The Mn component (B1) includes simple Mn, inorganic Mn compounds, and organic Mn compounds.

Examples of inorganic Mn compounds include Mn oxides such as manganese dioxide; manganese boride; inorganic acid Mn salts such as manganese carbonate, manganese phosphate, manganese borate, manganese sulfate, and manganese nitrate; and Mn halides such as manganese chloride. These inorganic Mn compounds can be used alone or in combination of two or more. Of these, manganese dioxide, manganese carbonate, and manganese phosphate are preferred.

Examples of shapes of Mn simple substance and inorganic Mn compounds include spherical (true spherical or nearly spherical), ellipsoidal (elliptical sphere), polyhedral (polygonal pyramid, polygonal column such as cube or rectangular parallelepiped, etc.), rod or stick, fibrous, acicular, and irregular shapes. Of these, granular shapes such as spherical, ellipsoidal, polyhedral, and irregular shapes are preferred because they can improve adhesion to the ceramic substrate, and isotropic shapes (particularly spherical) such as spheres and regular polyhedral shapes (regular hexahedron, cube, regular octahedron, etc.) are particularly preferred.

The median particle size (D50) of particles formed from simple Mn and inorganic Mn compounds is, for example, about 0.1 to 10 μm, preferably 0.3 to 5 μm, more preferably 0.5 to 3 μm, and most preferably about 0.8 to 2 μm. If the particle size is too small, the economic efficiency decreases and dispersibility in the conductive composition may also decrease. Conversely, if the particle size is too large, the printability and uniformity of the fired film decrease, and when printing with a mesh screen, it may cause the mesh to become clogged.

The organic Mn compound may be a carboxylate Mn salt such as manganese formate, manganese acetate, manganese oxalate, manganese butyrate, manganese caproate, manganese octoate, manganese neodecanoate, manganese stearate, or manganese naphthenate. The organic Mn compound may be a Mn-based metal soap (e.g., a higher fatty acid Mn salt such as manganese octoate, manganese neodecanoate, or manganese stearate). These organic Mn compounds may be used alone or in combination of two or more. Of these, _C4-24 saturated fatty acid manganese such as manganese octoate is preferred. The organic Mn compound (particularly, _C4-24 saturated fatty acid Mn salt) may be used in the form of a liquid composition. The liquid composition may be a hydrocarbon solution such as a petroleum-based hydrocarbon solution (e.g., a mineral spirit solution).

As the Mn component (B1), inorganic Mn compounds and organic Mn compounds are preferred, Mn oxides such as manganese dioxide and C _6-18 saturated fatty acid Mn salts such as manganese octylate are more preferred, and C _6-12 saturated fatty acid Mn salts are most preferred.

The proportion of the Mn component (B1) is, in terms of Mn element (as a proportion of Mn element), for example, 0.01 to 1 part by mass, preferably 0.03 to 0.5 parts by mass, more preferably 0.1 to 0.3 parts by mass (e.g., 0.15 to 0.25 parts by mass), and most preferably about 0.2 to 0.3 parts by mass, relative to 100 parts by mass of the Ag particles (A). The proportion of the Mn component (B1) in the metal component (B) is, in terms of Mn element, for example, 3 to 20% by mass, preferably 5 to 15% by mass, and more preferably about 7.5 to 10% by mass. If the proportion of the Mn component (B1) is too low, the denseness of the fired body may decrease, and conversely, if it is too high, the electrical conductivity may decrease.

(Fe component (B2))
The Fe component (B2) includes simple Fe, inorganic Fe compounds, and organic Fe compounds.

Examples of inorganic Fe compounds include Fe oxides such as iron (II) oxide, iron (III) oxide (iron trioxide), and triiron tetroxide; iron boride; iron hydroxide; iron sulfide; inorganic acid Fe salts such as iron carbonate, iron phosphate, iron borate, iron sulfate, and iron nitrate; and Fe halides such as iron chloride. These inorganic Fe compounds can be used alone or in combination of two or more. Of these, iron oxide (II), iron oxide (III), triiron tetroxide, and iron phosphate are preferred.

The shapes of the Fe element and inorganic Fe compounds, including preferred embodiments, are the same as those of the Mn element and inorganic Mn compounds.

The median particle size (D50) of particles formed from simple Fe and inorganic Fe compounds is, for example, about 0.1 to 10 μm, preferably 0.3 to 5 μm, more preferably 0.5 to 3 μm, and most preferably about 0.8 to 2 μm. If the particle size is too small, the economic efficiency decreases and dispersibility in the conductive composition may also decrease. Conversely, if the particle size is too large, the printability and uniformity of the fired film decrease, and when printing with a mesh screen, it may cause the mesh to become clogged.

Examples of the organic Fe compound include Fe carboxylates such as iron formate, iron acetate, iron oxalate, iron butyrate, iron caproate, iron octylate, iron neodecanoate, iron stearate, and iron naphthenate; and metal complexes such as acetylacetone metal complex (ferric nursem). Examples of the organic Fe compound include Fe-based metal soaps (for example, higher fatty acid Fe salts such as iron octylate, iron neodecanoate, and iron stearate). These organic Fe compounds can be used alone or in combination of two or more. Of these, C _4-24 saturated fatty acid Fe salts such as iron octylate are preferred. The organic Fe compound (particularly, C _4-24 saturated fatty acid Fe salts) may be used in the form of a liquid composition. The liquid composition may be a hydrocarbon solution such as a petroleum-based hydrocarbon solution (for example, a mineral spirit solution).

As the Fe component (B2), inorganic Fe compounds and Fe carboxylates are preferred, iron oxide and _C6-18 saturated fatty acid Fe salts are more preferred, and iron(II) oxide is most preferred.

The proportion of the Fe component (B2) is, in terms of Fe element (as a proportion of Fe element), for example, 0.01 to 1 part by mass, preferably 0.03 to 0.5 parts by mass, more preferably 0.1 to 0.3 parts by mass (e.g., 0.15 to 0.25 parts by mass), and most preferably about 0.13 to 0.2 parts by mass, relative to 100 parts by mass of the Ag particles (A). The proportion of the Fe component (B2) in the metal component (B) is, in terms of Fe element, for example, 3 to 15% by mass, preferably 4 to 10% by mass, and more preferably about 5 to 8% by mass. If the proportion of the Fe component (B2) is too low, the denseness of the fired body may decrease, and conversely, if it is too high, the electrical conductivity may decrease.

(Cu component (B3))
The Cu component (B3) includes simple Cu, inorganic Cu compounds, and organic Cu compounds.

Examples of inorganic Cu compounds include Cu oxides such as copper oxide; copper hydroxide; copper sulfide; inorganic acid Cu salts such as copper carbonate, copper phosphate, copper borate, copper sulfate, and copper nitrate; and Cu halides such as copper chloride. These inorganic Cu compounds can be used alone or in combination of two or more. Of these, copper oxide, copper carbonate, and copper phosphate are preferred.

The shapes of Cu alone and inorganic Cu compounds, including preferred embodiments, are the same as those of Mn alone and inorganic Mn compounds.

The median particle size (D50) of particles formed from simple Cu and inorganic Cu compounds is, for example, about 0.1 to 10 μm, preferably 0.5 to 5 μm, and more preferably about 1 to 3 μm. If the particle size is too small, the economic efficiency decreases and dispersibility in the conductive composition may also decrease. Conversely, if the particle size is too large, the printability and uniformity of the fired film decrease, and when printing with a mesh screen, it may cause the mesh to become clogged.

Examples of the organic Cu compounds include carboxylates such as copper formate, copper acetate, copper oxalate, copper butyrate, copper caproate, copper octylate, copper neodecanoate, and copper naphthenate; and metal complexes such as acetylacetone metal complex (nacem copper). Examples of the organic Cu compounds include Cu-based metal soaps (such as higher fatty acid Cu salts such as copper neodecanoate and copper naphthenate). These organic Cu compounds can be used alone or in combination of two or more. Among these, cyclic fatty acid Cu salts such as copper naphthenate (such as fatty acid Cu salts having C _4-8 cycloalkane carboxylic acids such as cyclopentane and cyclohexane) and C _4-24 saturated fatty acid Cu salts such as copper neodecanoate are preferred. The organic Cu compounds (particularly cyclic fatty acid Cu salts) may be used in the form of a liquid composition. The liquid composition may be a hydrocarbon solution such as a petroleum-based hydrocarbon solution (such as a mineral spirit solution).

As the Cu component (B3), Cu alone, inorganic Cu compounds, and Cu carboxylates are preferred, copper alone, copper oxide, and a mineral spirit solution of cyclic fatty acid copper are more preferred, and a combination of Cu alone with copper oxide and/or Cu carboxylates is particularly preferred. Of these, it is particularly preferred to include copper oxide, and a combination of Cu alone with copper oxide is most preferred.

When combining elemental Cu with copper oxide and/or a Cu carboxylate (particularly copper oxide), the ratio of the former to the latter, calculated in terms of Cu element (as the ratio of Cu element), is about 50/1 to 1/1, preferably 30/1 to 3/1, more preferably 20/1 to 5/1, and most preferably about 15/1 to 8/1.

The proportion of Cu component (B3) can be selected from the range of about 0.01 to 5 parts by mass (e.g., 0.1 to 5 parts by mass) per 100 parts by mass of Ag particles (A) in terms of Cu element (as the proportion of Cu element), and is, for example, about 0.5 to 5 parts by mass, preferably 1 to 4 parts by mass, more preferably 1.5 to 3 parts by mass, and most preferably about 2 to 2.5 parts by mass. The proportion of Cu component (B3) in metal component (B) is, for example, about 70 to 90% by mass, preferably 80 to 88% by mass, and more preferably about 83 to 86% by mass, in terms of Cu element. If the proportion of Cu component (B3) is too low, the denseness of the fired body may decrease, and conversely, if it is too high, the conductivity may decrease.

(Preferred embodiment of metal component (B))
From the viewpoint of improving reliability, the metal component (B) preferably contains an organometallic compound (i.e., an organic Mn compound, an organic Fe compound, or an organic Cu compound), and any of the Mn component (B1), the Fe component (B2), and the Cu component (B3) may contain an organometallic compound. Among them, it is preferable that one or two of the Mn component (B1), the Fe component (B2), and the Cu component (B3) are organometallic compounds (particularly, metal carboxylates), and it is particularly preferable that only one is an organometallic compound. Furthermore, it is preferable that at least the Mn component (B1) or the Fe component (B2) is an organometallic compound, it is more preferable that at least the Mn component (B1) is an organometallic compound, and it is particularly preferable that only the Mn component (B1) is an organometallic compound. In particular, in the present invention, when the organometallic compound is blended in the form of a liquid composition, reliability can be further improved.

When the Mn component (B1) is an organometallic compound (particularly, a _C6-12 saturated fatty acid Mn salt), the Fe component (B2) is preferably an inorganic Fe compound and/or an organic Fe compound, more preferably an iron oxide and/or an Fe carboxylate, and particularly preferably Fe ₂ O _3. The Cu component (B3) is preferably at least one selected from the group consisting of simple Cu, an inorganic Cu compound, and a fatty acid Cu salt having a _C4-8 cycloalkane ring, more preferably contains copper oxide, and particularly preferably a combination of simple Cu and copper oxide.

When the Fe component (B2) is an organometallic compound (particularly, a _C6-12 saturated fatty acid Fe salt), the Mn component (B1) is preferably one or more selected from inorganic Mn compounds and organic Mn compounds, more preferably manganese oxide and/or a carboxylate Mn salt, and particularly preferably manganese oxide or a _C6-12 saturated fatty acid Mn salt. The Cu component (B3) is preferably one or more selected from simple Cu, inorganic Cu compounds, and cyclic fatty acid Cu salts, more preferably simple Cu and/or a fatty acid Cu salt having a _C4-8 cycloalkane ring, and particularly preferably simple Cu.

When the Cu component (B3) contains an organometallic compound (particularly a fatty acid Cu salt having a _C4-8 cycloalkane ring), the Mn component (B1) is preferably an inorganic Mn compound and/or an organic Mn compound, more preferably manganese oxide and/or a Mn carboxylate, and particularly preferably manganese oxide or a _C6-12 saturated fatty acid Mn salt. The Fe component (B2) is preferably an inorganic Fe compound and/or an organic Fe compound, more preferably iron oxide and/or _a Fe carboxylate, more preferably _Fe2O3 or _{a C6-12} saturated fatty acid Fe salt, and particularly preferably _Fe2O3 .

Of these combinations, the most preferred is a combination in which the Mn component (B1) is an organometallic compound (particularly, a _C6-12 saturated fatty acid Mn salt), the Fe component (B2) is an inorganic Fe compound (particularly, iron oxide), and the Cu component (B3) is an inorganic Cu compound (particularly, a combination of simple Cu and copper oxide).

(Proportion of Metal Component (B))
The ratio of the metal component (B) can be selected from the range of about 0.1 to 10 parts by mass relative to 100 parts by mass of Ag particles (A) in terms of metal elements (as the total ratio of Mn element, Fe element and Cu element), for example, 0.5 to 5 parts by mass, preferably 0.7 to 4.5 parts by mass (e.g., 1 to 4 parts by mass), more preferably 0.8 to 3.7 parts by mass (e.g., 2 to 3.5 parts by mass), and most preferably about 2.5 to 3 parts by mass. If the ratio of the metal component (B) is too small, the denseness of the fired body may decrease, and conversely, if it is too large, the conductivity may decrease.

[Glass particles (C)]
The glass particles (glass powder) (C) need only function as a sintering aid, and conventional glass particles used for electrical conductors can be used.

The composition of the glass constituting the glass particles (C) is not particularly limited, and examples thereof include borosilicate glass (silica-based glass) represented by the composition formula SiO ₂ -B ₂ O ₃ -R ₂ O (wherein R represents an alkali metal such as K or Na), aluminosilicate glass represented by the composition formula Al ₂ O ₃ -SiO ₂ -MO-R ₂ O (wherein M represents an element other than Al and Si, and R is the same as above), aluminoborosilicate glass represented by the composition formula Al ₂ O ₃ -SiO ₂ -B ₂ O ₃ -MO-R ₂ O (wherein M represents an element other than Al, Si, and B, and R is the same as above), bismuth-based glass represented by the composition formula Bi ₂ O ₃ -MO-B ₂ O ₃ (wherein M represents an element other than Bi and B), and ZnO-SiO ₂ -B ₂ O ₃ -R ₂ O (wherein R is the same as above). These glasses can be used alone or in combination of two or more. Among these, bismuth-based glass and/or zinc-based glass are preferred, and bismuth-based glass is particularly preferred, from the viewpoint of improving plating resistance. Glass particles having these glass compositions can also be used alone or in combination of two or more.

The softening point (or melting point) of the glass particles (C) is preferably lower than the firing temperature of the conductive composition. The softening point of the glass particles is, for example, about 400 to 800°C, preferably 420 to 780°C, more preferably 450 to 750°C, even more preferably 460 to 600°C, and most preferably 470 to 550°C. If the softening point is too low, the strength of the fired body may decrease, and conversely, if it is too high, the melt flowability may decrease, and the function as a binder may decrease.

The shape of the glass particles (C), including the preferred embodiment, is the same as that of the small Ag particles (A1).

The median particle size (D50) of the glass particles (C) is, for example, 0.1 to 20 μm, preferably 0.5 to 10 μm, and more preferably about 1 to 5 μm. If the particle size is too small, the economic efficiency decreases and dispersibility in the composition may also decrease. Conversely, if the particle size is too large, the printability and uniformity of the fired film decrease, and when printing with a mesh screen, it may cause the mesh to become clogged.

The proportion of glass particles (C) can be selected from the range of about 0.05 to 15 parts by mass per 100 parts by mass of Ag particles (A), for example, about 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, more preferably 1 to 5 parts by mass, and most preferably about 2 to 4 parts by mass. If the proportion of glass particles (C) is too low, the function as a sintering aid may decrease, and the effect of improving plating resistance may also decrease, and conversely, if it is too high, there is a risk of reduced electrical conductivity.

[Resin component (D)]
The conductive composition of the present invention may further contain a resin component (D) as an organic binder. The resin component (D) is not particularly limited, and examples thereof include thermoplastic resins (olefin resins, vinyl resins, acrylic resins, styrene resins, polyether resins, polyester resins, polyamide resins, cellulose derivatives, etc.), thermosetting resins (thermosetting acrylic resins, epoxy resins, phenolic resins, unsaturated polyester resins, polyurethane resins, etc.). These resin components can be used alone or in combination of two or more. Among these resin components, resins that are easily burned off during the firing process and have low ash content, such as acrylic resins (polymethyl methacrylate, polybutyl methacrylate, etc.), cellulose derivatives (nitrocellulose, ethyl cellulose, butyl cellulose, cellulose acetate, etc.), polyethers (polyoxymethylene, etc.), rubbers (polybutadiene, polyisoprene, etc.), etc. are commonly used, and cellulose derivatives such as ethyl cellulose are preferred.

The proportion of resin component (D) is, for example, about 0.1 to 5 parts by mass, preferably 0.3 to 3 parts by mass, more preferably 0.5 to 2 parts by mass, and most preferably about 0.8 to 1.5 parts by mass, per 100 parts by mass of Ag particles (A). If the proportion of resin component (D) is too low, the handleability of the conductive composition may decrease, and conversely, if it is too high, the density of the fired body may decrease.

[Organic solvent (E)]
The conductive composition of the present invention may further contain an organic solvent (E). The organic solvent (E) is not particularly limited, and may be an organic compound that imparts appropriate viscosity to the conductive composition (particularly a paste-like composition) and can be easily volatilized by drying treatment after the conductive composition is applied to a substrate, and may be a high-boiling organic solvent.

Examples of such organic solvents include aromatic hydrocarbons (paraxylene, ethylbenzene, trimethylbenzene, naphthalene, cumene, indene, etc.), aliphatic hydrocarbons (hexane, heptane, octane, nonane, etc.), esters (ethyl lactate, texanol, etc.), ketones (isophorone, etc.), amides (dimethylformamide, etc.), aliphatic alcohols (ethanol, isopropanol, butanol, octanol, 2-ethylhexanol, decanol, diacetone alcohol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates (ethyl cellosolve acetate, butyl cellosolve acetate, etc.), carbitols (carbitol, methyl carbitol, ethyl carbitol, ethyl carbitol, etc.), and methyl carbitol. Examples of suitable organic solvents include carbitol acetates (ethyl carbitol acetate, butyl carbitol acetate), aliphatic polyhydric alcohols (ethylene glycol, diethylene glycol, dipropylene glycol, butanediol, triethylene glycol, glycerin, etc.), alicyclic alcohols [for example, cycloalkanols such as cyclohexanol; terpene alcohols (monoterpene alcohols, etc.) such as α-terpineol and dihydroterpineol], aromatic alcohols (metacresol, etc.), aromatic carboxylic acid esters (dibutyl phthalate, dioctyl phthalate, etc.), and nitrogen-containing heterocyclic compounds (dimethylimidazole, dimethylimidazolidinone, etc.). These organic solvents can be used alone or in combination of two or more.

Among these organic solvents, from the viewpoint of the fluidity of the conductive composition, aliphatic diol monocarboxylates such as Texanol (2,2,4-trimethylpentane-1,3-diol monoisobutyrate), aliphatic alcohols such as octanol, alicyclic alcohols such as terpineol, carbitols such as butyl carbitol, and carbitol acetates such as butyl carbitol acetate are preferred, and a combination of the aliphatic diol monocarboxylate and the carbitol acetates is particularly preferred. When the aliphatic diol monocarboxylate and the carbitol acetates are combined, the mass ratio of the two is the former/latter = 99/1 to 10/90, preferably 90/10 to 30/70, and more preferably 80/20 to 50/50 (particularly 75/25 to 60/40). Furthermore, from the viewpoint of improving reliability, it is preferable to use organic solvents such as petroleum-based hydrocarbons (or mineral spirits), including aromatic and aliphatic hydrocarbons.

The proportion of the organic solvent (E) can be selected from the range of about 0.01 to 50 parts by mass relative to 100 parts by mass of Ag particles (A), and is, for example, about 1 to 30 parts by mass, preferably 3 to 20 parts by mass, more preferably 5 to 15 parts by mass, and most preferably about 8 to 13 parts by mass. When the organic solvent (E) contains a petroleum-based hydrocarbon, the proportion of the petroleum-based hydrocarbon is, for example, 0.01 to 30 parts by mass, preferably 0.05 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, and most preferably 1 to 3 parts by mass relative to 100 parts by mass of Ag particles (A). If the proportion of the organic solvent (E) is too small, the viscosity of the conductive composition may increase, resulting in a decrease in handleability and reliability, and conversely, if the proportion is too large, the denseness of the fired body may decrease.

[Other metal-containing components (F)]
The conductive composition of the present invention may further contain a metal-containing component (other metal-containing component) (F) other than the Ag particles (A), the metal component (B), and the glass particles (C).

Other metal-containing components (F) include, for example, metal components (metal elements, metal compounds) of metal elements selected from the group consisting of Pd, Al, Ni, Mo, W, Pt, Au, Co, Ti, Zr, Sn, etc., Ag compounds, alloys or composite metal compounds of two or more metal elements selected from the above group and Ag, Mn, Fe, Cu, etc.

The shapes of the other metal-containing components, including preferred embodiments, are the same as those of the Ag small particles (A1).

The particle size of the particles formed by the other metal-containing component (F) is not particularly limited and can be selected from a range of about 0.5 to 30 μm as the median particle size (D50), for example, about 1 to 10 μm, preferably 1 to 4 μm, and more preferably about 1.5 to 3 μm (particularly 1.5 to 2.5 μm). If the median particle size is too small, there is a risk that adhesion to the ceramic substrate will decrease, and conversely, if it is too large, there is a similar risk that adhesion will decrease.

The proportion of the other metal-containing component (F), calculated as the metal element, may be about 5 parts by mass or less (e.g., 0.01 to 5 parts by mass) per 100 parts by mass of the Ag particles (A).

[Conventional Additives]
The conductive composition of the present invention may further contain conventional additives within a range that does not impair the effects of the present invention. Examples of conventional additives include curing agents (such as curing agents for acrylic resins), colorants (such as dyes and pigments), hue improvers, dye fixing agents, gloss-imparting agents, metal corrosion inhibitors, stabilizers (such as antioxidants and ultraviolet absorbers), surfactants or dispersants (such as anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants), dispersion stabilizers, viscosity modifiers or rheology modifiers, moisturizing agents, thixotropic agents, leveling agents, defoamers, bactericides, and fillers. These other components can be used alone or in combination of two or more. The total proportion of conventional additives can be selected depending on the type of component, and is usually about 10 parts by mass or less (for example, 0.01 to 10 parts by mass) relative to 100 parts by mass of Ag particles (A).

[Method of preparing conductive composition]
The conductive composition (or conductive paste) of the present invention can be prepared by mixing the components using a conventional mixer to uniformly disperse the components, or by using a device having a grinding function (e.g., a three-roll mill, a mortar, a mill, etc.). The components can be added in a lump and mixed, or in portions and mixed.

In the present invention, it is preferable to add at least one selected from the group consisting of the Mn component (B1), the Fe component (B2) and the Cu component (B3) in the form of a liquid composition, in order to improve plating resistance.

[Metallized substrate and manufacturing method thereof]
The metallized substrate (ceramic substrate with conductive portion such as a wiring circuit board) of the present invention is obtained through an adhesion step of adhering the conductive composition to a ceramic substrate, and a firing step of firing the conductive composition adhered to the ceramic substrate to form a conductive portion.

In the present invention, in terms of improving reliability, when the metal component (B) contains an organometallic compound, the organometallic compound may be added in the form of a liquid composition, and it is more preferable to add at least one selected from the group consisting of the Mn component (B1), the Fe component (B2), and the Cu component (B3) in the form of a liquid composition, and it is particularly preferable to add at least the Mn component (B1) in the form of a liquid composition.

In the attachment process, the method of attaching the conductive composition can be selected according to the type of metallized substrate. In surface metallized substrates and through-hole wall metallized substrates, the conductive composition may be applied to the substrate surface or the inner walls of the through holes (through holes), and in via-filled substrates, the conductive composition may be filled into the front and back through holes (via filling).

As a method for forming a coating film using a conductive composition, a conventional coating method such as a flow coating method, a dispenser coating method, a spin coating method, a spray coating method, a screen printing method, a flexographic printing method, a casting method, a bar coating method, a curtain coating method, a roll coating method, a gravure coating method, a dipping method, a slit method, a photolithography method, an inkjet method, etc. can be used. In the coating method, a pattern may be formed (drawn) with the coating film, and a pattern (sintered film, metal film, sintered body layer, conductor layer) can be formed by drying the formed pattern (drawn pattern). The drawing method (or printing method) for drawing the pattern (coating layer) is not particularly limited as long as it is a printing method capable of forming a pattern, and examples thereof include a screen printing method, an inkjet printing method, an intaglio printing method (e.g., gravure printing method, etc.), an offset printing method, an intaglio offset printing method, and a flexographic printing method. Of these, a screen printing method is preferred.

Examples of materials for the ceramic substrate include metal oxides (alumina or aluminum oxide, zirconia, sapphire, ferrite, zinc oxide, niobium oxide, mullite, beryllia, etc.), silicon oxides (quartz, silicon dioxide, etc.), metal nitrides (aluminum nitride, titanium nitride, etc.), silicon nitride, boron nitride, carbon nitride, metal carbides (titanium carbide, tungsten carbide, etc.), silicon carbide, boron carbide, metal double oxides [metal titanates (barium titanate, strontium titanate, lead titanate, niobium titanate, calcium titanate, magnesium titanate, etc.), metal zirconates (barium zirconate, calcium zirconate, lead zirconate, etc.)], etc. These ceramics can be used alone or in combination of two or more kinds.

Among these ceramic substrates, alumina substrates, alumina-zirconia substrates, aluminum nitride substrates, silicon nitride substrates, and silicon carbide substrates are preferred because of their high reliability in the electrical and electronic fields, with alumina substrates, aluminum nitride substrates, and silicon nitride substrates being more preferred, and alumina substrates being the most preferred.

The thickness of the ceramic substrate may be appropriately selected depending on the application, and may be, for example, about 0.001 to 10 mm, preferably 0.01 to 5 mm, and more preferably 0.05 to 3 mm (particularly 0.1 to 1 mm).

The firing atmosphere is preferably air. The firing temperature is sufficient as long as it exceeds the softening point of the glass particles in the conductive composition, and is, for example, about 600 to 1100°C, preferably about 700 to 1000°C, and more preferably about 800 to 950°C. The firing time is, for example, about 1 minute to 3 hours, preferably about 10 minutes to 2 hours, and more preferably about 30 minutes to 1.5 hours.

Firing may be carried out using a batch furnace or a belt-conveying tunnel furnace.

The metallized substrate of the present invention has excellent electrical conductivity, and the resistivity of the conductive portion may be 3 μΩ·cm or less (e.g., 1 to 3 μΩ·cm).

The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. In the following examples, the materials used in the examples, the evaluation substrates obtained in the examples, and the evaluation methods for the obtained substrates are shown below.

[Materials used]
(Ag particles)
Ag particle a: spherical, particle size distribution (D10 to D90) 0.42 to 1.24 μm, 10% particle size (D10) 0.42 μm, center particle size (D50) 0.5 μm, 90% particle size (D90) 1.24 μm, maximum particle size 4.63 μm, specific surface area 1.3 m ² /g
Ag particle b: spherical, particle size distribution (D10 to D90) 1.2 to 3.1 μm, 10% particle size (D10) 1.2 μm, center particle size (D50) 2 μm, 90% particle size (D90) 3.1 μm, maximum particle size 7.8 μm, specific surface area 0.4 m ² /g
Ag particles c: flake-like, median particle size (D50): about 6 μm
Ag particles d: flake-like, median particle size (D50): about 1.1 μm, specific surface area: 1.6 m ² /g

(Metal Component)
Copper (Cu) particles: spherical, center particle diameter (D50) 3 μm
Copper oxide (CuO) particles: purity 3N, average particle size approximately 1 μm
Cu naphthenate: Copper naphthenate mineral spirits solution, Cu content 8% by mass
Iron oxide (Fe ₂ O ₃ ) particles: purity 2N, average particle size approximately 1 μm
Fe octylate: solution of iron octylate in mineral spirits, Fe content 6% by mass
Manganese oxide (MnO) particles: purity 3N, average particle size approximately 1 μm
Mn octylate: manganese (II) octylate solution in mineral spirits, Mn content 8% by mass

(Glass particles)
Bismuth-based glass particles: composition Bi ₂ O ₃ --ZnO--B ₂ O ₃ , softening temperature 488° C.
Zinc-based glass particles: composition ZnO-- _SiO.sub.2 -- _{B.sub.2O.sub.3 -- R.sub.2O} , softening temperature 575.degree. C.
Silica-based glass particles: composition SiO ₂ --B ₂ O ₃ --R ₂ O, softening temperature 780°C.

(Resin Component)
Ethyl cellulose: "STD20" manufactured by The Dow Chemical Company.

[Preparation of Evaluation Board]
Conductive pastes of Examples 1 to 17 and Comparative Examples 1 to 15 were prepared with the compositions shown in Tables 1 to 6. The pastes were prepared by mixing an organic vehicle in which 10% by mass of ethyl cellulose was dissolved in a mixed solvent of Texanol/Butyl Carbitol Acetate = 55/35 (mass ratio) with the inorganic components shown in Tables 1 to 6. At that time, the solid content concentration of the inorganic components in the conductive paste was adjusted to 87% by mass. Then, using the prepared paste, electrodes were formed by screen printing on an alumina substrate of 3 inches x 3 inches x 0.635 mm thick, and the electrodes were fired at 900°C in air to prepare evaluation substrates.

[Resistivity]
The resistivity was calculated from the surface resistance measured by a four-probe method and the film thickness. Ten samples of the conductive films obtained in the examples and comparative examples were measured, and the average value was calculated.

[Plating resistance, initial adhesive strength]
After electroless plating (Ni/Pd/Au), the adhesion was evaluated at a 2 mm square pad pattern portion. A tin-plated soft copper wire (peel wire) was soldered along the surface of the 2 mm square pad.

The soft copper wire was bent vertically upward at the end of the pad, fixed to a tensile tester, and pulled up until the pad peeled off from the substrate. The highest load at which the pad peeled off from the substrate was recorded as the peel strength (peel strength of 2 mm square pattern) and used as the initial adhesive strength. A peel strength of 3.0 kgf or more means that the peel strength per 1 mm square pattern is 0.75 kgf or more, and if the electrode peeled off simply by lifting the copper wire, it was recorded as 0 kgf.

[Initial Judgment]
The results of the above plating resistance evaluation test (initial adhesive strength) were initially judged and ranked according to the following criteria.

Rank A: The initial adhesive strength is 3.0 kgf or more. Rank B: The initial adhesive strength is 2.0 kgf or more and less than 3.0 kgf. Rank C: The initial adhesive strength is less than 2.0 kgf.

For boards that passed the initial assessment, the following reliability evaluation was performed to evaluate the adhesive strength.

[Constant temperature and humidity test]
In the constant temperature and humidity test, the sample was left in a constant temperature and humidity chamber at a temperature of 85° C. and a relative humidity of 85% RH for 1000 hours, and then the adhesion (adhesive strength) of the fired film was measured and rated according to the following criteria.

◎: 2.5 kgf or more ○: 2.0 kgf or more but less than 2.5 kgf ×: Less than 2.0 kgf.

[Heat cycle test]
The adhesive strength after 1000 cycles of -40°C/125°C was measured and rated according to the following criteria.

◎: 2.5 kgf or more ○: 2.0 kgf or more but less than 2.5 kgf ×: Less than 2.0 kgf.

[Heat aging test]
After 1000 hours in an oven at 170° C., the adhesive strength was measured and rated according to the following criteria.

◎: 2.5 kgf or more ○: 2.0 kgf or more but less than 2.5 kgf ×: Less than 2.0 kgf.

[Overall Judgment]
The results of the above evaluation tests were comprehensively judged and ranked according to the following criteria.

Rank A: All reliability tests are ◎ or 〇 (passed)
Rank B: All reliability tests are ○ (passed)
Rank C: The reliability test was judged to be ×, or the initial judgment was rank C (failed).

The evaluation results of the evaluation substrates obtained in Examples 1 to 17 and Comparative Examples 1 to 15 are also shown in Tables 1 to 6.

The details of the percentages (mass%) listed in Tables 1 to 6 are as follows:

"Ratio of metal component (B) to Ag particles (A)" means the ratio (mass %) of metal component (B) to Ag particles (A) (i.e., the total amount of Ag particles a and Ag particles b) in terms of metal elements (parts by mass of metal elements contained in metal component (B) to 100 parts by mass of the total amount of Ag particles a and Ag particles b).

"Proportion of metal component (B) in inorganic components" means the proportion (mass %) of metal component (B) in metal element equivalent to the total amount of Ag particles (A), metal component (B) and glass particles (C) in metal element equivalent.

"Proportion of Mn component (B1) in metal component (B)" means the proportion (mass%) of Mn component (B1) in terms of metal elements relative to metal component (B) (i.e., the total amount of Mn component (B1), Fe component (B2) and Cu component (B3) in terms of metal elements). The same applies to the proportions of Fe component (B2) and Cu component (B3).

"Ratio of glass particles (C) to Ag particles (A)" means the parts by mass of glass particles (C) per 100 parts by mass of Ag particles (A).

"Proportion of glass particles (C) in the inorganic component" means the proportion (mass%) of glass particles (C) relative to the total amount of Ag particles (A), metal component (B) and glass particles (C) calculated as metal elements.

As is clear from the results in Tables 1 and 2, when small Ag particles (A1) and large Ag particles (A2) were included, and all three components, Mn component (B1), Fe component (B2), and Cu component (B3), excellent plating resistance (adhesion) was obtained in the initial plating resistance evaluation and in the reliability evaluation (Examples 1 to 3). Among them, the properties of Examples 1 and 2, in which the proportion of small Ag particles (A1) in the Ag particles exceeds 5 mass%, were excellent, with Example 1 being the most excellent.

The results of Example 1, which had the best balance of properties, are shown not only in Table 1, but also in Tables 3, 5 and 6 for comparison.

On the other hand, when the material contained all three components, Mn (B1), Fe (B2), and Cu (B3) (and one of them was a metal carboxylate), but only contained small Ag particles (A1) or large Ag particles (A2), the initial plating resistance was B or higher, but the reliability evaluation failed (Comparative Examples 1 to 7).

Comparative Examples 8 and 9 are also examples containing only one of small Ag particles (A1) and large Ag particles (A2), and containing all three components, Mn (B1), Fe (B2), and Cu (B3), but no metal carboxylate. Similarly, although the initial plating resistance test passed, the reliability test failed. Comparative Examples 8 and 9 have a similar composition to the paste disclosed in Patent Document 4.

Tables 3 and 4 show examples (Examples 4 to 9) in which the combination of the types of Mn component (B1), Fe component (B2), and Cu component (B3) was changed compared to Example 1, which gave good results in Table 1. All of these examples are examples in which one or more of the three metal components contain a metal carboxylate, and in all cases, excellent plating resistance (adhesion) was obtained in the initial plating resistance assessment and in the reliability evaluation. Among these, Example 1, which contains one type of manganese octylate, was the best.

On the other hand, even when small Ag particles (A1) and large Ag particles (A2) were included, Comparative Examples 10 and 11, which contained only two of the Mn component (B1), Fe component (B2), and Cu component (B3), passed the initial plating resistance test but failed the reliability test. Comparative Example 12 failed the plating resistance test because the electrodes did not adhere at all. Furthermore, Comparative Examples 13 to 15, which contained only one of the Mn component (B1), Fe component (B2), and Cu component (B3), also failed the plating resistance test because the electrodes did not adhere at all.

As is clear from the results in Table 5, the results of Examples 10 and 11, in which the ratio (total amount) of the three metal components to the Ag particles was varied compared to Example 1, show that the ratio is preferably about 0.5 to 5.0 mass%.

In addition, in Examples 12 and 13, in which the distribution ratio of Mn compound (B1), Fe compound (B2), and Cu compound (B3) was changed from Example 1, the same results as Example 1 were obtained, but Example 1 was the most superior in terms of reliability.

As is clear from the results in Table 6, in comparison with Example 1, Example 14, which uses zinc-based glass particles, and Example 15, which uses silica-based glass particles, also gave results equivalent to those of Example 1, but bismuth-based glass and zinc-based glass were particularly excellent.

In addition, in Examples 16 and 17, in which the amount of glass particles was reduced and increased compared to Example 1, the same results as in Example 1 were obtained. However, in Example 16, in which the amount was reduced, the adhesive strength after the heat aging test was slightly decreased, and in Example 17, in which the amount was increased, the adhesive strength after the heat cycle test was slightly decreased.

The conductive composition of the present invention can be used for circuit boards, electronic components, thermal substrates, substrates for LED packages, substrates for semiconductors, thin-film circuit substrates, substrates for resistors, etc., and can be particularly effectively used as a composition for forming conductive parts such as electrodes in wiring circuit boards.

Claims (9)

A conductive composition comprising Ag particles (A), a metal component (B) and glass particles (C),
the Ag particles (A) are small Ag particles (A1) and large Ag particles (A2);
a mass ratio of the small Ag particles (A1) to the large Ag particles (A2) is 99/1 to 30/70;
the small Ag particles (A1) are spherical or regular polyhedral particles having a maximum particle size of less than 1.2 μm, and the large Ag particles (A2) are spherical or regular polyhedral particles having a minimum particle size of 1.2 μm or more,
In the small Ag particles (A1) and the large Ag particles (A2), the ratio of the major axis to the minor axis of the spherical particles is 1 to 2;
The Ag small particles (A1) have a median particle size (D50) of 0.4 μm or more,
The metal component (B) is a Mn component (B1), an Fe component (B2) and a Cu component (B3), and
The conductive composition , wherein at least one selected from the group consisting of the Mn component (B1), the Fe component (B2) and the Cu component (B3) is an organometallic compound . The conductive composition according to claim 1, wherein the large Ag particles (A2) are spherical particles with a median particle size (D50) of 1.3 to 10 μm. The conductive composition according to claim 1 or 2, wherein the mass ratio of the small Ag particles (A1) to the large Ag particles (A2) is 90/10 to 30/70. The conductive composition according to any one of claims 1 to 3, wherein the glass particles (C) contain bismuth-based glass particles and/or zinc-based glass particles. The method for producing a conductive composition according to any one of claims 1 to 4, wherein at least one selected from the group consisting of the Mn component (B1), the Fe component (B2), and the Cu component (B3) is added in the form of a liquid composition. A method for manufacturing a metallized substrate, comprising: an attachment step of attaching the conductive composition according to any one of claims 1 to 4 to a ceramic substrate; and a firing step of firing the conductive composition attached to the ceramic substrate to form a conductive portion. The manufacturing method according to claim 6, wherein the conductive composition is fired in air in the firing step. A metallized substrate obtained by the manufacturing method described in claim 6 or 7. The metallized substrate according to claim 8, wherein the ceramic substrate is an alumina substrate, an alumina-zirconia substrate, an aluminum nitride substrate, a silicon nitride substrate, or a silicon carbide substrate.