JP2011159836A - Method of manufacturing wiring board, conductor pattern forming ink set, and wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method, capable of efficiently manufacturing a reliable wiring board with a reliable conductor pattern, by preventing the occurrence of cracks, disconnections, short circuit, or the like. <P>SOLUTION: The method of manufacturing the wiring board of the present invention includes: a step of preparing a ceramic compact consisting of materials including a ceramic material and binder; a step of forming a conductor pattern precursor by discharging conductor pattern forming ink including metal particles and a dispersion medium that disperses the metal particles by a droplet discharge method, to the ceramic compact; a step of providing composition including dispersion-lowering agents, which lowers the dispersion of the metal particles in the conductor pattern forming ink, at least to a part of the ceramic compact, where the conductor pattern forming ink has been provided; a step of obtaining a laminated body by laminating a plurality of ceramic compacts; and a step of obtaining the wiring board having the conductor pattern and a ceramic substrate by sintering the laminated body. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a wiring board, a conductive pattern forming ink set, and a wiring board.

As a circuit board (wiring board) on which electronic components are mounted, a ceramic circuit board in which wiring made of a metal material is formed on a board made of ceramics (ceramic board) is widely used. In such a ceramic circuit board, since the board (ceramic board) itself is made of a multifunctional material, it is advantageous in terms of formation of interior parts by multi-layering, dimensional stability, and the like.
Such a ceramic circuit board is provided with a composition containing metal particles in a pattern corresponding to a wiring (conductor pattern) to be formed on a ceramic molded body made of a material containing ceramic particles and a binder. Thereafter, the ceramic molded body to which the composition is applied is manufactured by degreasing and sintering.

  A screen printing method is widely used as a method for forming a pattern on a ceramic molded body. On the other hand, in recent years, there has been a demand for higher density of circuit boards by finer wiring and narrower pitch, but screen printing is disadvantageous for finer wiring and narrower pitch. Difficult to meet demand. Therefore, in recent years, a so-called ink jet method has been proposed as a method for forming a pattern on a ceramic molded body, in which a liquid material containing metal particles (ink for forming a conductor pattern) is ejected in droplets from a liquid ejection head. (For example, refer to Patent Document 1). According to this method, it is possible to form a fine conductor pattern as compared with the conventional method, which is advantageous in improving the circuit density.

  However, the conventional method using the ink-jet method may cause cracks in the conductor pattern, increase the specific resistance, or cause disconnection or short-circuiting, so that the reliability and yield of the formed conductive pattern (wiring board) are sufficient. It was difficult to make it high. Such a tendency has become conspicuous as the thickness of the conductor pattern to be formed increases and the wiring density increases (thinning of the wiring).

JP 2007-84387 A

  An object of the present invention is to provide a highly reliable wiring board having a highly reliable conductor pattern in which the occurrence of cracks, disconnections, short circuits, etc. is prevented, and to efficiently manufacture the wiring board. It is another object of the present invention to provide a manufacturing method and to provide an ink set for forming a conductor pattern that can be suitably used for manufacturing the wiring board.

Such an object is achieved by the present invention described below.
The method for manufacturing a wiring board according to the present invention includes a ceramic molded body preparation step of preparing a sheet-shaped ceramic molded body made of a material containing a ceramic material and a binder,
A conductor pattern precursor forming step of forming a conductor pattern precursor by discharging a conductive pattern forming ink containing metal particles and a dispersion medium in which the metal particles are dispersed to the ceramic molded body by a droplet discharge method;
Dispersibility in which a composition containing a dispersibility reducing agent that reduces the dispersibility of the metal particles in the conductive pattern forming ink is applied to at least a portion of the ceramic molded body to which the conductive pattern forming ink is applied. A reducing agent application step;
A laminating step of laminating a plurality of the ceramic molded bodies to obtain a laminated body;
And firing the laminate to obtain a wiring substrate having a conductor pattern and a ceramic substrate.
As a result, it is possible to provide a method for manufacturing a wiring board capable of efficiently manufacturing a highly reliable wiring board having a highly reliable conductor pattern in which the occurrence of cracks, disconnections, short circuits, and the like is prevented. .

In the method for manufacturing a wiring board of the present invention, it is preferable that the composition containing the dispersibility-reducing agent is selectively applied to a region to which the conductive pattern forming ink is applied.
Thereby, the usage-amount of the composition containing a dispersibility reducing agent can be suppressed, and the production cost of a wiring board can be suppressed.
In the method for manufacturing a wiring board according to the present invention, it is preferable to apply the composition containing the dispersibility reducing agent by a droplet discharge method.
Thereby, the position selectivity at the time of providing the composition containing a dispersibility reducing agent can be made more excellent, and formation of a fine conductor pattern can be performed more suitably.

In the method for producing a wiring board according to the present invention, the dispersibility reducing agent is preferably at least one selected from the group consisting of alkyl esters of lactic acid and alkyl ethers of polyhydric alcohols.
Thereby, the reliability of a conductor pattern can be made higher.
In the method for manufacturing a wiring board according to the present invention, it is preferable that the conductor pattern forming ink contains a polyglycerin compound.
Thereby, the reliability of a conductor pattern can be made higher.

In the method for manufacturing a wiring board of the present invention, the ceramic molded body preferably contains polyvinyl butyral as the binder.
Thereby, the reliability of a conductor pattern can be made higher.
In the method for manufacturing a wiring board of the present invention, it is preferable that the conductive pattern forming ink contains an aqueous dispersion medium as the dispersion medium.
Thereby, the reliability of a conductor pattern can be made higher.

The conductive pattern forming ink set of the present invention is a conductive pattern forming ink set for forming a conductive pattern on a substrate by patterning,
A conductive pattern forming ink comprising metal particles and a dispersion medium in which the metal particles are dispersed;
And a dispersibility-reducing agent-containing ink containing a composition containing a dispersibility reducing agent that lowers the dispersibility of the metal particles in the conductive pattern forming ink.
Thus, it is possible to provide an ink set for forming a conductor pattern that can be suitably used for manufacturing a highly reliable wiring board having a highly reliable conductor pattern in which occurrence of cracks, disconnections, short circuits, and the like is prevented. Can do.
The wiring board of the present invention is manufactured using the method of the present invention.
As a result, it is possible to provide a highly reliable wiring board provided with a highly reliable conductor pattern in which the occurrence of cracks, disconnections, short circuits, and the like is prevented.

It is sectional drawing which shows suitable embodiment of the manufacturing method of the wiring board (ceramics circuit board) of this invention. It is a perspective view which shows schematic structure of an inkjet apparatus. It is a schematic diagram for demonstrating schematic structure of an inkjet head.

Hereinafter, preferred embodiments of the present invention will be described in detail.
<Method for manufacturing wiring board>
First, the manufacturing method of the wiring board of this invention is demonstrated.
FIG. 1 is a cross-sectional view showing a preferred embodiment of a method of manufacturing a wiring board (ceramic circuit board) according to the present invention, FIG. 2 is a perspective view showing a schematic configuration of an ink jet apparatus (droplet discharge apparatus), and FIG. FIG. 2 is a schematic diagram for explaining a schematic configuration of an inkjet head (droplet discharge head).

  The method of manufacturing a wiring board according to the present embodiment includes a step of preparing a plurality of sheet-like ceramic molded bodies 15 made of a material including a ceramic material and a binder (ceramic molded body preparing step), A step of forming a conductor pattern precursor 10 by discharging a conductive pattern forming ink 200 containing metal particles and a dispersion medium in which the metal particles are dispersed on at least one surface by a droplet discharge method (conductor pattern precursor) And a dispersibility reducing agent that reduces the dispersibility of the metal particles in the conductor pattern forming ink 200 at least on the portion of the ceramic molded body 15 to which the conductor pattern forming ink 200 is applied. And a laminated body 17 by laminating a plurality of ceramic molded bodies 15. Obtained in the step (laminating step), heating the laminated body 17, and a step (firing step) to obtain a wiring substrate 30 having the conductive pattern 20 and the ceramic substrate 31.

(Ceramic molded body preparation process)
In this step, a plurality of sheet-like ceramic molded bodies (ceramic green sheets) 15 made of a material containing a ceramic material and a binder are prepared.
<Ceramic compact>
Moreover, the ceramic molded body 15 becomes a ceramic substrate 31 by being sintered as described later.

When obtaining a ceramic molded body (green sheet) 15 containing a plurality of types of powder, it is preferable to mix the plurality of types of powder in advance prior to mixing with a binder or the like.
As the ceramic material, ceramic powder such as alumina (Al ₂ O ₃ ) or titanium oxide (TiO ₂ ) can be suitably used depending on the design value of the dielectric constant.
The average particle size of the ceramic powder is preferably 1 μm or more and 2 μm or less.

In this step, it is preferable to use glass powder as the raw material powder in addition to the ceramic powder. Depending on the composition, the glass powder begins to melt at a temperature of 500 to 700 ° C. or higher. Therefore, during the sintering process of the ceramic formed body, first, an organic binder such as polyvinyl butyral is oxidatively decomposed (volatilized), and then the glass powder is melted, so that alumina (Al ₂ O ₃ ) or oxidized having a very high melting point. It functions as an inorganic binder for ceramic powder such as titanium (TiO ₂ ). Thereby, the dimensional accuracy, mechanical strength, and dielectric constant characteristics of the sintered ceramic substrate can be further improved.

As glass powder, borosilicate glass etc. can be used suitably, for example.
The average particle size of the glass powder is preferably 1 μm or more and 2 μm or less.
The mixing ratio of the ceramic powder and the glass powder is preferably 2: 1 or more and 1: 2 or less by weight.
A slurry is obtained by mixing and stirring the above raw material powder with a binder (binder) or the like.

  As the binder, polyvinyl butyral is preferably used, but it is insoluble in water and easily dissolved or swelled in a so-called oil-based organic solvent. Further, by using polyvinyl butyral as a binder, the dispersibility reducing agent can be reliably held in the vicinity of the surface of the ceramic molded body, and the function of the dispersibility reducing agent as described in detail later is more effectively exhibited. be able to. As a result, the reliability of the formed conductor pattern 20 can be made higher.

In the preparation of the slurry, a plasticizer, an organic solvent (functioning as a dispersion medium for dispersing the raw material powder), a dispersant, and the like may be used.
The ceramic molded body 15 can be suitably obtained, for example, by forming a slurry into a sheet shape on a PET film using a doctor blade, a reverse coater, or the like.
The thickness of the ceramic molded body 15 is preferably several μm or more and several hundreds μm or less.

The ceramic molded body 15 formed into a sheet shape as described above is usually wound around a roll, cut according to the application of the product, and further cut into a sheet having a predetermined size. In this embodiment, for example, it is cut into a square shape having a side length of 200 mm.
Further, through holes (through holes) are formed at predetermined positions by drilling with a CO ₂ laser, a YAG laser, a mechanical punch or the like as necessary.

  Then, by filling this through hole with a thick film conductive paste in which metal particles are dispersed, a portion (conductor post 16) to be the contact 33 is formed. As the thick film conductive paste, a conductor pattern forming ink as described later can be used. The filling of the thick film conductive paste may be performed in this step, may be performed in a conductor pattern precursor forming step described later, or is performed after the conductor pattern precursor forming step. It may be a thing.

(Conductor pattern precursor formation process)
A conductive pattern forming ink 200 (hereinafter also simply referred to as “ink 200”) as described in detail later is applied to the surface of at least one side of the ceramic green sheet (ceramic molded body) 15 obtained as described above. The conductive pattern precursor 10 to be the circuit 20 is formed by applying a droplet discharge (inkjet) method. Thereby, the ceramic molded body 15 provided with the precursor 10 is obtained.
And the conductor pattern precursor 10 fuse | melts metal particles by sintering, and forms the conductor pattern 20 mentioned later.

Hereinafter, the conductive pattern forming ink 200 used in this step will be described in detail.
<Conductor pattern forming ink>
The conductor pattern forming ink 200 is ink used to form the conductor pattern precursor 10 by a droplet discharge method.
In the present embodiment, a case where a dispersion liquid in which silver particles as metal particles are dispersed in an aqueous dispersion medium is used as the conductor pattern forming ink 200 will be representatively described.

Hereinafter, each component of the conductive pattern forming ink 200 will be described in detail.
[Aqueous dispersion medium]
In the present embodiment, the conductor pattern forming ink 200 includes an aqueous dispersion medium. As described above, since the conductor pattern forming ink 200 includes the aqueous dispersion medium as the dispersion medium, the dispersion medium is more preferably removed from the conductor pattern forming ink 200 discharged onto the ceramic molded body 15. 15, a layer (conductor pattern precursor 10) in which metal particles are concentrated can be more suitably formed on the ceramic molded body 15. As a result, the reliability of the formed conductor pattern 20 can be made higher.

  In the present invention, the “aqueous dispersion medium” refers to a liquid composed of water and / or a liquid having excellent compatibility with water (for example, a liquid having a solubility in 100 g of water at 25 ° C. of 30 g or more). . As described above, the aqueous dispersion medium is composed of water and / or a liquid having excellent compatibility with water, but is preferably composed mainly of water. It is preferably 70 wt% or more, more preferably 90 wt% or more. Thereby, the effect mentioned above is exhibited more notably.

Specific examples of the aqueous dispersion medium include, for example, water, methanol, ethanol, butanol, propanol, isopropanol and other alcohol solvents, 1,4-dioxane, tetrahydrofuran (THF) and other ether solvents, pyridine, pyrazine, pyrrole and the like. Aromatic heterocyclic compound solvents, amide solvents such as N, N-dimethylformamide (DMF) and N, N-dimethylacetamide (DMA), nitrile solvents such as acetonitrile, and aldehyde solvents such as acetaldehyde. Of these, one or a combination of two or more can be used.
The content of the aqueous dispersion medium in the conductive pattern forming ink 200 is preferably 25 wt% or more and 60 wt% or less, and more preferably 30 wt% or more and 50 wt% or less. Thereby, while making the viscosity of the ink 200 suitable, the change of the viscosity by volatilization of a dispersion medium can be made small.

[Silver particles]
Next, silver particles (metal particles) will be described.
Silver particles are a main component of the conductor pattern 20 to be formed, and are components that impart conductivity to the conductor pattern 20.
The silver particles are dispersed in the ink.

  The average particle diameter of the silver particles is preferably 1 nm or more and 100 nm or less, and more preferably 10 nm or more and 30 nm or less. As a result, the ink ejection stability can be further improved, and a fine conductor pattern can be easily formed. In the present specification, the “average particle size” means a volume-based average particle size unless otherwise specified.

In the ink 200, the average interparticle distance between silver particles is preferably 1.7 nm or more and 380 nm or less, and more preferably 1.75 nm or more and 300 nm or less. Thereby, the viscosity of the ink 200 for forming a conductor pattern can be made more appropriate, and the discharge stability is particularly excellent.
In addition, the content of silver particles (silver particles (metal particles) in which the dispersant is not adsorbed on the surface) contained in the ink 200 is preferably 0.5 wt% or more and 60 wt% or less, and is preferably 10 wt% or more and 45 wt%. % Or less is more preferable. Thereby, the disconnection of the conductor pattern 20 can be prevented more effectively, and the conductor pattern 20 with higher reliability can be provided.

The silver particles (metal particles) are preferably dispersed in an aqueous dispersion medium as silver colloid particles (metal colloid particles) having a dispersant attached to the surface thereof. Thereby, the dispersibility of the silver particles in the aqueous dispersion medium is particularly excellent, and the ejection stability of the ink 200 is particularly excellent.
Although it does not specifically limit as a dispersing agent, it has 3 or more of COOH groups and OH groups, and the number of COOH groups is the same as that of OH groups, or contains hydroxy acid or its salt more than it. Is preferred. These dispersants adsorb on the surface of silver particles to form colloidal particles, and the colloidal liquid is stabilized by uniformly dispersing silver colloidal particles in an aqueous solution by the electric repulsive force of COOH groups present in the dispersant. Has the function of As described above, since the silver colloid particles are stably present in the ink 200, the fine conductor pattern 20 can be more easily formed. Further, silver particles are uniformly distributed in the pattern (precursor 10) formed by the ink 200, and cracks, disconnections, and the like are less likely to occur. On the other hand, if the number of COOH groups and OH groups in the dispersant is less than 3 or the number of COOH groups is less than the number of OH groups, the dispersibility of the silver colloid particles cannot be sufficiently obtained. There is a case.

Examples of such a dispersing agent include citric acid, malic acid, trisodium citrate, tripotassium citrate, trilithium citrate, triammonium citrate, disodium malate, tannic acid, gallotannic acid, and pentaploid tannin. Of these, one or a combination of two or more can be used.
Further, the dispersant may contain mercapto acid or a salt thereof having two or more COOH groups and SH groups. In these dispersants, mercapto groups are adsorbed on the surface of silver fine particles to form colloidal particles, and colloidal particles are uniformly dispersed in an aqueous solution by the electric repulsive force of COOH groups present in the dispersant. Has the function of stabilizing As described above, since the silver colloid particles are stably present in the ink 200, the fine conductor pattern 20 can be more easily formed. Further, silver particles are uniformly distributed in the pattern (precursor 10) formed by the ink 200, and cracks, disconnections, and the like are less likely to occur. On the other hand, when the number of COOH groups and SH groups in the dispersant is less than 2, that is, only one, the dispersibility of the silver colloidal particles may not be sufficiently obtained.

  Examples of such dispersants include mercaptoacetic acid, mercaptopropionic acid, thiodipropionic acid, mercaptosuccinic acid, thioacetic acid, sodium mercaptoacetate, sodium mercaptopropionate, sodium thiodipropionate, disodium mercaptosuccinate, Examples include potassium mercaptoacetate, potassium mercaptopropionate, potassium thiodipropionate, dipotassium mercaptosuccinate, and the like, and one or more of these can be used in combination.

  The content of the silver colloid particles in the ink 200 is preferably 1 wt% or more and 60 wt% or less, more preferably 5 wt% or more and 50 wt% or less. When the content of the silver colloid particles is less than the lower limit, the silver content is small, and when the conductive pattern 20 is formed, it is necessary to apply the coating multiple times when a relatively thick film is formed. On the other hand, when the content of the silver colloidal particles exceeds the upper limit, the silver content increases and the dispersibility decreases. To prevent this, the frequency of stirring increases.

  Further, the heat loss to 500 ° C. in the thermogravimetric analysis of the silver colloid particles is preferably 1 wt% or more and 25 wt% or less. When the colloidal particles (solid content) are heated to 500 ° C., the dispersant adhering to the surface, the reducing agent (residual reducing agent) described later and the like are oxidized and decomposed, and most of them are gasified and disappear. Since the amount of the residual reducing agent is considered to be small, the weight loss due to heating up to 500 ° C. is considered to substantially correspond to the amount of the dispersant in the silver colloid particles. When the loss on heating is less than 1 wt%, the amount of the dispersant with respect to the silver particles is small, and the sufficient dispersibility of the silver particles is lowered. On the other hand, when it exceeds 25 wt%, the amount of the residual dispersant with respect to the silver particles increases, and the specific resistance of the conductor pattern increases. However, the specific resistance can be improved to some extent by heating and sintering after formation of the conductor pattern 20 to decompose and disappear organic components. Therefore, it is effective for a ceramic substrate that is sintered at a higher temperature.

[Organic binder]
Further, the conductor pattern forming ink 200 may contain an organic binder. The organic binder prevents aggregation of silver particles in the conductor pattern precursor 10 formed using the conductor pattern forming ink 200. That is, in the formed conductor pattern precursor 10, the organic binder can be prevented from being agglomerated with each other due to the presence of the organic binder between the silver particles and causing cracks in a part of the pattern. Further, at the time of sintering, the organic binder can be decomposed and removed, and the silver particles in the conductor pattern precursor 10 are combined to form the conductor pattern 20.

  Further, since the conductor pattern forming ink 200 contains an organic binder, the adhesion of the conductor pattern precursor 10 to the ceramic molded body 15 can be made particularly excellent, and the metal constituting the conductor pattern precursor 10 The flow of particles to unintentional sites is more reliably prevented. As a result, the occurrence of cracks, disconnections, short circuits, etc. can be more effectively prevented, and the conductor pattern 20 can be formed with higher accuracy. That is, the reliability of the finally obtained conductor pattern 20 can be made particularly high.

  Although it does not specifically limit as an organic binder, For example, polyethyleneglycol # 200 (weight average molecular weight 200), polyethyleneglycol # 300 (weight average molecular weight 300), polyethyleneglycol # 400 (average molecular weight 400), polyethyleneglycol # 600 ( Weight average molecular weight 600), polyethylene glycol # 1000 (weight average molecular weight 1000), polyethylene glycol # 1500 (weight average molecular weight 1500), polyethylene glycol # 1540 (weight average molecular weight 1540), polyethylene glycol # 2000 (weight average molecular weight 2000), etc. Polyethylene glycol, polyvinyl alcohol # 200 (weight average molecular weight: 200), polyvinyl alcohol # 300 (weight average molecular weight: 300), polyvinyl alcohol # 400 (average molecular weight: 400), polyvinyl alcohol # 600 (weight average molecular weight: 600), polyvinyl alcohol # 1000 (weight average molecular weight: 1000), polyvinyl alcohol # 1500 (weight average molecular weight: 1500), polyvinyl alcohol # Polyglycerin compounds having a polyglycerin skeleton such as polyvinyl alcohol such as 1540 (weight average molecular weight: 1540), polyvinyl alcohol # 2000 (weight average molecular weight: 2000), polyglycerin, polyglycerin ester, etc. Alternatively, two or more kinds can be used in combination. Examples of polyglycerol esters include polyglycerol monostearate, tristearate, tetrastearate, monooleate, pentaoleate, monolaurate, monocaprylate, polycinnolate, sesquistearate, decaoleate, and sesquioleate. Etc.

Among these, when a polyglycerin compound is used as the organic binder, the following effects can be obtained.
The polyglycerin compound particularly suitably prevents the conductor pattern precursor 10 from cracking when the conductor pattern precursor 10 formed using the conductor pattern forming ink 200 is dried (dedispersing medium). be able to. This is considered as follows. By including the polyglycerin compound in the conductive pattern forming ink 200, a polymer chain exists between the silver particles (metal particles), and the polyglycerin compound makes the distance between the silver particles moderate. be able to. Furthermore, since the polyglycerin compound has a relatively high boiling point, it is not removed when the aqueous dispersion medium is removed, and adheres around the silver particles. As described above, at the time of removing the aqueous dispersion medium, the polyglycerin compound continuously encapsulates the silver particles, and as a result, rapid volume shrinkage due to volatilization of the aqueous dispersion medium is avoided and silver grain growth (aggregation) is hindered. It is considered that generation of cracks in the conductor pattern precursor 10 is suppressed.

  In addition, the polyglycerin compound can more reliably prevent the occurrence of disconnection during sintering when the conductor pattern 20 is formed. This is considered as follows. Polyglycerin compounds have a relatively high boiling point or decomposition temperature. For this reason, in the process of forming the conductor pattern 20 from the conductor pattern precursor 10, the conductor pattern is not evaporated or thermally (oxidized) decomposed to a relatively high temperature after the water-based dispersion medium evaporates. It can be present in the precursor 10. Therefore, until the polyglycerin compound evaporates or is thermally (oxidized) decomposed, the polyglycerin compound exists around the silver particles, and the approach and aggregation of the silver particles can be suppressed, and the polyglycerin compound is decomposed. Later, the silver particles can be joined more uniformly. Furthermore, a polymer chain (polyglycerin compound) exists between silver particles (metal particles) in the pattern during sintering, and the polyglycerin compound can keep the distance between the silver particles. Moreover, this polyglycerin compound has moderate fluidity | liquidity. For this reason, by including the polyglycerin compound, the conductor pattern precursor 10 has excellent followability to expansion / contraction due to temperature change of the ceramic molded body 15.

From the above, it is considered that disconnection of the formed conductor pattern 20 can be more reliably prevented.
Moreover, by including such a polyglycerin compound, the viscosity of the ink 200 can be made more appropriate, and the ejection stability from the inkjet head 110 can be improved more effectively. In addition, film formability can be improved.

  Among the above-mentioned polyglycerin compounds, polyglycerin is preferably used. Polyglycerin is particularly excellent in the ability to follow expansion and contraction due to temperature changes of the ceramic molded body 15 and is a component that can be more reliably removed from the conductor pattern 20 after the ceramic molded body 15 is sintered. . As a result, the electrical characteristics of the conductor pattern 20 can be made higher. Furthermore, since polyglycerin has high solubility in an aqueous dispersion medium, it can be suitably used.

  The organic binder preferably has a weight average molecular weight of 300 or more and 3000 or less, more preferably 400 or more and 1000 or less, and still more preferably 400 or more and 600 or less. Thereby, when the pattern formed using the conductor pattern forming ink 200 is dried, the generation of cracks can be more reliably prevented. On the other hand, when the weight average molecular weight of the organic binder is less than the lower limit, depending on the composition of the organic binder, the organic binder tends to be decomposed when removing the aqueous dispersion medium, thereby preventing the occurrence of cracks. The effect is reduced. When the weight average molecular weight of the organic binder exceeds the upper limit, the solubility and dispersibility in the ink 200 may be reduced due to the excluded volume effect or the like depending on the composition of the organic binder.

  Further, the content of the organic binder in the ink 200 is preferably 1 wt% or more and 30 wt% or less, and more preferably 5 wt% or more and 20 wt% or less. This makes it possible to more effectively prevent the occurrence of cracks and disconnections while making the ejection stability of the ink 200 particularly excellent. On the other hand, when the content of the organic binder is less than the lower limit, the effect of preventing the occurrence of cracks may be reduced depending on the composition of the organic binder. Further, when the content of the organic binder exceeds the upper limit, it may be difficult to make the viscosity of the ink 200 sufficiently low depending on the composition of the organic binder.

(Drying inhibitor)
Further, the conductor pattern forming ink 200 may contain a drying inhibitor. The drying inhibitor prevents unintended volatilization of the aqueous dispersion medium in the ink 200. As a result, the aqueous dispersion medium can be prevented from volatilizing in the vicinity of the ejection portion of the ink jet apparatus, and the increase in viscosity and drying of the ink 200 can be suppressed. As a result of including such a drying inhibitor, the conductive pattern forming ink 200 has excellent discharge stability of the droplets of the ink 200. That is, the variation in the weight of the droplets of ink 200 is small, and clogging, flight bending, and the like are small. In particular, even after the ink jet device is filled with the conductor pattern forming ink 200 and the ink jet device is in a standby state without being operated for a long period of time (for example, five days), the conductor pattern forming ink is used. In a uniform amount, it can be accurately discharged to a target position.
Examples of such a drying inhibitor include compounds represented by the following formula (I), alkanolamines, sugar alcohols, and the like, and one or more of them can be used in combination.

（ただし、Ｒ、Ｒ’は、それぞれ、Ｈまたはアルキル基である。）

(However, R and R ′ are each H or an alkyl group.)

The compound represented by the above formula (I) is a component having a high hydrogen bonding property. For this reason, it has a high affinity with water, can retain an appropriate amount of water, and can prevent the volatilization of the aqueous dispersion medium of the conductive pattern forming ink 200.
Further, the compound is relatively easily combusted and can be more easily removed (oxidative decomposition) from the conductor pattern forming ink 200 when the conductor pattern 20 is formed.
In addition, when the metal particles (silver particles) are colloidal particles having a dispersant attached to the surface as described above, the compound as described above is bonded to the surface dispersant by hydrogen bonding, and the dispersion stability of the metal particles. Has the effect of improving. Accordingly, the ejection stability of the conductor pattern forming ink 200 is excellent, and the storage stability is also excellent.

  As described above, R and R ′ in the compound represented by the above formula (I) used in the present invention are each hydrogen or an alkyl group, but R and R ′ are both hydrogen. preferable. That is, urea is preferable. As a result, the moisture retention as described above can be made particularly high, and particularly excellent ejection stability can be obtained. Further, when the metal particles are present as colloidal particles as described above, particularly excellent dispersion stability is exhibited.

  The content of the compound represented by the above formula (I) in the ink is preferably 5 wt% or more and 25 wt% or less, more preferably 8 wt% or more and 20 wt% or less, and 10 wt% or more and 18 wt% or less. % Or less is more preferable. Thereby, unintentional drying of the conductor pattern forming ink 200 can be prevented more efficiently. As a result, the ejection stability of the ink 200 can be made particularly excellent.

Alkanolamine is a highly moisturizing component, and when the metal particles are colloidal particles as described above, the functional group of the dispersant on the surface of the colloidal particles can be activated, and the dispersion stability of the metal particles Can be higher.
Examples of the alkanolamine include monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, and tripropanolamine.

The alkanolamine is preferably a tertiary amine. Tertiary amines have particularly high moisture retention among alkanolamines, and can make the above effects more remarkable.
Among tertiary amines, it is particularly preferable to use triethanolamine from the viewpoints of ease of handling, high moisture retention, and the like.
The content of alkanolamine in the conductor pattern forming ink 200 is preferably 1 wt% or more and 10 wt% or less, and more preferably 3 wt% or more and 7 wt% or less. Thereby, the ejection stability of the conductor pattern forming ink 200 can be more effectively improved.

Sugar alcohol is obtained by reducing aldehyde groups and ketone groups of sugars.
Sugar alcohol is a compound having high moisture retention. In addition, since sugar alcohol has a large number of oxygen per molecular weight, it is easily decomposed and removed when the atmosphere reaches the decomposition temperature of sugar alcohol. For this reason, when the conductor pattern 20 is formed, the sugar alcohol is reliably removed from the formed conductor pattern 20 by oxidizing the temperature of the conductor pattern precursor 10 higher than the decomposition temperature of the sugar alcohol (oxidative decomposition). )can do.

  Examples of sugar alcohols include threitol, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, arabitol, ribitol, xylitol, sorbitol, mannitol, threitol, glycol, tallitol, galactitol, allitol, altritol, dolitol, iditol. Glycerin (glycerol), inositol, maltitol, isomaltitol, lactitol, tranitol and the like, and one or more of these can be used in combination.

  The content of the sugar alcohol in the conductor pattern forming ink 200 as described above is preferably 3 wt% or more and 20 wt% or less, and more preferably 5 wt% or more and 15 wt% or less. Thereby, volatilization of the aqueous dispersion medium of the conductor pattern forming ink 200 can be more reliably suppressed, and the conductor pattern forming ink 200 has particularly excellent droplet ejection stability over a longer period of time.

[Surface tension modifier]
Further, the conductor pattern forming ink 200 may contain a surface tension adjusting agent.
The surface tension adjusting agent has a function of adjusting the contact angle between the conductor pattern forming ink 200 and the ceramic molded body 15 to a predetermined angle.
As the surface tension adjusting agent, various surfactants can be used, and one or a combination of two or more types can be used, but it is preferable to include an acetylene glycol compound.

  The contact angle between the conductive pattern forming ink 200 and the ceramic molded body 15 can be adjusted to a predetermined range with a small addition amount of the acetylene glycol compound. Thus, the finer conductor pattern 20 can be formed by adjusting the contact angle between the conductor pattern forming ink 200 and the ceramic molded body 15 within a predetermined range. Further, even when bubbles are mixed in the discharged droplets, the bubbles can be quickly removed. As a result, generation of cracks and disconnections in the formed conductor pattern 20 can be more effectively prevented.

  Examples of acetylene glycol compounds include Surfynol 104 series (104E, 104H, 104PG-50, 104PA, etc.), Surfynol 400 series (420, 465, 485, etc.), Olphine series (EXP4036, EXP4001, E1010, etc.). ("Surfinol" and "Orphine" are trade names of Nissin Chemical Industry Co., Ltd.) and the like, and one or more of these can be used in combination.

The ink 200 preferably contains two or more acetylene glycol compounds having different HLB values. The contact angle between the conductor pattern forming ink 200 and the ceramic molded body 15 can be easily adjusted within a predetermined range.
In particular, the difference between the HLB value of the acetylene glycol compound having the highest HLB value and the HLB value of the acetylene glycol compound having the lowest HLB value among two or more acetylene glycol compounds contained in the ink 200 is as follows. It is preferably 4 or more and 12 or less, and more preferably 5 or more and 10 or less. As a result, the contact angle between the conductor pattern forming ink 200 and the ceramic molded body 15 can be easily adjusted within a predetermined range with a smaller addition amount of the acetylene glycol compound.

When the ink 200 contains two or more acetylene glycol compounds, the HLB value of the acetylene glycol compound having the highest HLB value is preferably 8 or more and 16 or less, and 9 or more and 14 or less. Is more preferable.
When the ink 200 contains two or more acetylene glycol compounds, the HLB value of the acetylene glycol compound having the lowest HLB value is preferably 2 or more and 7 or less, and is 3 or more and 5 or less. More preferably.
The content of the surface tension adjusting agent contained in the ink 200 is preferably 0.001 wt% or more and 1 wt% or less, and more preferably 0.01 wt% or more and 0.5 wt% or less. As a result, the contact angle between the conductor pattern forming ink 200 and the ceramic molded body 15 can be adjusted more effectively within a predetermined range.

[Other ingredients]
The constituent components of the conductor pattern forming ink 200 are not limited to the above components, and may include components other than those described above.
Examples of such components include thiourea, arginine, histidine and the like.

  The viscosity of the conductive pattern forming ink 200 is not particularly limited, but is preferably 1 mPa · s or more and 20 mPa · s or less, and more preferably 3 mPa · s or more and 8 mPa · s or less. As a result, the droplet ejection stability can be improved, and the unintentional wetting and spreading of the ink 200 that has landed on the ceramic molded body 15 can be more reliably prevented, and the fine line width can be reduced. The conductor pattern precursor 10 can be formed.

In the present embodiment, the conductive pattern forming ink 200 as described above can be discharged by using, for example, the ink jet apparatus (droplet discharge apparatus) 100 shown in FIGS. Hereinafter, the ink jet apparatus 100 and droplet discharge using the ink jet apparatus 100 will be described.
FIG. 2 is a perspective view of the ink jet apparatus 100. In FIG. 2, the X direction is the left-right direction of the base 130, the Y direction is the front-rear direction, and the Z direction is the up-down direction.

The ink jet apparatus 100 includes an ink jet head (droplet discharge head; hereinafter simply referred to as “head”) 110, a base 130, a table 140, a control device 190, a table positioning means 170, and a head positioning means shown in FIG. 180.
The base 130 is a table that supports each component of the droplet discharge device 100 such as the table 140, the table positioning unit 170, and the head positioning unit 180.

The table 140 is installed on the base 130 via the table positioning means 170. The table 140 is used for placing the substrate S (the ceramic green sheet 15 in the present embodiment).
A rubber heater (not shown) is disposed on the back surface of the table 140. The entire upper surface of the ceramic green sheet 15 placed on the table 140 is heated to a predetermined temperature by a rubber heater.

  As described above, the ink 200 that has landed on the ceramic green sheet 15 is absorbed by the ceramic molded body 15 at least a part of the aqueous dispersion medium that is a component thereof, and at least a part of the aqueous dispersion medium from the surface side. Evaporates. At this time, since the ceramic green sheet 15 is heated, the evaporation of the aqueous dispersion medium is promoted, and the content of the aqueous dispersion medium in the layer in which the metal particles are concentrated (conductor pattern precursor 10) is effectively reduced. Is done.

The heating temperature of the ceramic green sheet 15 is preferably 40 ° C. or higher and 100 ° C. or lower, and more preferably 50 ° C. or higher and 70 ° C. or lower, for example. By setting it as such conditions, when an aqueous dispersion medium evaporates, it can prevent more effectively that a crack generate | occur | produces.
The table positioning unit 170 includes a first moving unit 171 and a motor 172. The table positioning means 170 determines the position of the table 140 in the base 130, and thereby determines the position of the ceramic green sheet 15 in the base 130.

The first moving means 171 has two rails provided substantially parallel to the Y direction and a support base that moves on the rails. The support base of the first moving means 171 supports the table 140 via the motor 172. Then, as the support base moves on the rail, the table 140 on which the base material S is placed is moved and positioned in the Y direction.
The motor 172 supports the table 140 and swings and positions the table 140 in the θz direction.

The head positioning unit 180 includes a second moving unit 181, a linear motor 182, and motors 183, 184 and 185. The head positioning unit 180 determines the position of the head 110.
The second moving means 181 is provided with two support pillars standing from the base 130, a support base provided between the support pillars, the rail support having two rails, and the rails. And a support member (not shown) for supporting the head 110. Then, as the support member moves along the rail, the head 110 is moved and positioned in the X direction.

The linear motor 182 is provided in the vicinity of the support member, and can move and position the head 110 in the Z direction.
Motors 183, 184, and 185 swing and position the head 110 in the α, β, and γ directions, respectively.
By the table positioning unit 170 and the head positioning unit 180 as described above, the ink jet apparatus 100 accurately controls the relative position and posture of the ink ejection surface 115P of the head 110 and the base material S on the table 140. It can be done.

As shown in FIG. 3, the head 110 ejects the ink 200 from the nozzles (protruding portions) 118 by an ink jet method (droplet discharge method). In the present embodiment, the head 110 uses a piezo method in which ink is ejected using a piezo element 113 as a piezoelectric element. The piezo method has an advantage that the composition of the material is not affected because heat is not applied to the ink 200.
The head 110 has a head body 111, a diaphragm 112, and a piezo element 113.

The head main body 111 has a main body 114 and a nozzle plate 115 on the lower end surface thereof. Then, the main body 114 is sandwiched between the plate-like nozzle plate 115 and the vibration plate 112 to form a reservoir 116 as a space and a plurality of ink chambers 117 branched from the reservoir 116.
Ink 200 is supplied to the reservoir 116 from an ink tank (not shown). The reservoir 116 forms a flow path for supplying the ink 200 to each ink chamber 117.
The nozzle plate 115 is attached to the lower end surface of the main body 114 and constitutes an ink ejection surface 115P. In the nozzle plate 115, a plurality of nozzles 118 that discharge the ink 200 are opened corresponding to the ink chambers 117. An ink flow path is formed from each ink chamber 117 toward the corresponding nozzle 118.

The diaphragm 112 is attached to the upper end surface of the head body 111 and constitutes the wall surface of each ink chamber 117. The diaphragm 112 can vibrate according to the vibration of the piezo element 113.
The piezo element 113 is provided corresponding to each ink chamber 117 on the opposite side of the vibration plate 112 from the head body 111. The piezoelectric element 113 is obtained by sandwiching a piezoelectric material such as quartz with a pair of electrodes (not shown). The pair of electrodes is connected to the drive circuit 191.

When an electric signal is input from the drive circuit 191 to the piezo element 113, the piezo element 113 is expanded or contracted. When the piezo element 113 contracts and deforms, the pressure in the ink chamber 117 decreases, and the ink 200 flows from the reservoir 116 into the ink chamber 117. When the piezo element 113 expands and deforms, the pressure in the ink chamber 117 increases and the ink 200 is ejected from the nozzle 118. Note that the amount of deformation of the piezo element 113 can be controlled by changing the applied voltage. Further, the deformation speed of the piezo element 113 can be controlled by changing the frequency of the applied voltage. That is, by controlling the voltage applied to the piezo element 113, the ejection conditions of the ink 200 can be controlled.
The control device 190 controls each part of the inkjet device 100. For example, the discharge position of the ink 200 on the substrate S is controlled by adjusting the waveform of the applied voltage generated by the drive circuit 191 to control the discharge condition of the ink 200 or by controlling the head positioning unit 180 and the table positioning unit 170. Control.

  By using the ink jet apparatus 100 as described above, the ink 200 can be accurately ejected to a desired location on the ceramic green sheet 15 (base material S) with a desired amount. Furthermore, since the ceramic molded body (ceramic green sheet) 15 and the conductor pattern forming ink (ink) 200 as described above are used, the metal particles contained in the ink 200 ejected onto the ceramic green sheet 15 Involuntary movement from the landing position can be effectively prevented, and the conductor pattern precursor 10 having a desired shape can be reliably formed.

In addition, you may perform a drying process about the formed conductor pattern precursor 10. FIG. The drying process can be performed under the same conditions as the heating temperature of the ceramic green sheet 15 at the time of droplet discharge.
Adjustment of the thickness of the conductor pattern precursor 10 can be performed by setting the discharge conditions of the ink 200. That is, when forming a portion where the thickness of the conductor pattern precursor 10 is large, the ejection amount (or the number of droplets) of the ink 200 per area of the portion is made large, while the conductor pattern precursor 10 In the case where a portion having a small thickness is formed, the discharge amount (or the number of droplets) of the ink 200 per area of the portion can be reduced.

Further, when the drying inhibitor is included in the ink 200 after the dispersion medium is evaporated, there is no possibility that the pattern will be lost even when the formed precursor 10 is not completely dried. Accordingly, it is possible to apply the ink 200 once, dry it, leave it for a long time, and then apply the ink 200 again.
In addition, when the ink 200 includes the organic binder as described above, the organic binder (particularly, the polyglycerin compound) is a chemically and physically stable compound. Even if the ink 200 is left for a long time, the ink 200 does not change in quality, and the ink 200 can be applied again, and a more uniform pattern can be formed. Thereby, there is no possibility that the precursor 10 itself has a multilayer structure, and as a result, there is no possibility that the specific resistance between the layers increases and the specific resistance of the entire conductor pattern 20 increases.

(Dispersibility reducing agent application step)
By the way, the manufacturing method of the present invention is directed to a method of manufacturing a wiring board as a laminated board having a configuration in which ceramic substrates provided with conductor patterns are laminated. When the present inventors simply formed a conductor pattern precursor on a ceramic molded body and then laminated the ceramic molded body on which the conductor pattern precursor was formed, problems such as cracks, disconnections, and short circuits occurred. I found it easy to do. As a result of intensive studies by the inventor, it was presumed that the above problems were caused by the following reasons.

  That is, when the conductor pattern precursor is formed on the ceramic molded body, the dispersion medium contained in the conductor pattern forming ink is not processed until the step of laminating the ceramic molded body on which the conductor pattern precursor is formed (lamination process). Usually, a part of it is removed, but not all of it is removed. For this reason, when the ceramic molded body on which the conductor pattern precursor is formed is laminated in such a state, the conductor pattern precursor is crushed, and in the wiring board as the finally obtained laminated substrate, cracks, disconnection, short circuit, etc. The problem is likely to occur.

  In addition, it is conceivable to remove the dispersion medium contained in the conductor pattern precursor before the lamination step, but even in such a case, the occurrence of the above problems cannot be reliably prevented. This is because when the dispersion medium is removed by drying, relatively large voids exist between the metal particles constituting the conductor pattern precursor, and the conductor pattern precursor shrinks into a conductor pattern in the firing step. It is thought that.

  Therefore, as a result of earnest research for the purpose of solving the above problems, the present inventor has found that at least the conductive pattern forming ink of the ceramic molded body is present between the conductive pattern precursor forming step and the laminating step. By providing a dispersibility reducing agent applying step for applying a composition containing a dispersibility reducing agent for reducing the dispersibility of the metal particles in the conductive pattern forming ink to the applied portion (conductor pattern precursor), It was found that such problems can be solved. This is considered to be because the metal particles contained in the conductor pattern precursor are concentrated by applying the composition containing the dispersibility reducing agent, and a layer having excellent shape stability is formed.

Also in this embodiment, the dispersibility reducing agent provision process which provides a dispersibility reducing agent is performed between a dispersibility reducing agent provision process and the lamination process mentioned later.
The composition (dispersibility reducing agent-containing composition) containing the dispersibility reducing agent applied to the ceramic molded body 15 provided with the conductor pattern precursor 10 may be liquid, solid, or gaseous. For example, it may be molded into a predetermined shape, but is preferably liquid. This facilitates storage of the dispersibility-reducing agent-containing composition and easily adjusts the application pattern of the dispersibility-lowering agent-containing composition corresponding to the ceramic green sheet (ceramic molded body) 15 to be formed. be able to. Further, when the dispersibility reducing agent-containing composition is in a liquid form, the viscosity is not particularly limited, but is preferably 1 mPa · s or more and 20 mPa · s or less, and preferably 3 mPa · s or more and 8 mPa · s or less. It is more preferable. Thereby, the dispersibility reducing agent-containing composition can be suitably used for droplet discharge as described later.

In the following description, the case where the dispersibility-reducing agent-containing composition is a liquid composition (dispersibility-reducing agent-containing ink 300) will be representatively described.
<Dispersibility reducing agent-containing composition (dispersibility reducing agent-containing ink)>
(Dispersibility reducing agent)
The dispersibility reducing agent is not particularly limited as long as it has a function of reducing the dispersibility of the metal particles in the conductive pattern forming ink. For example, the conductive pattern forming ink is added by 10 parts by weight with respect to 100 parts by weight. When 24 hours have elapsed after mixing, the median particle diameter (Dv50) of the metal particle by a dynamic light scattering particle size distribution meter is more than twice that before addition / mixing, and the absorbance (Ag nanometer) by the UV spectrophotometer (Due to the plasmon absorption of the particles) preferably satisfies the condition of 0.7 times or less before addition / mixing, the median particle diameter before addition / mixing is 3 times or more, and the absorbance is It is more preferable that the condition of 0.4 times or less is satisfied.

  Specific examples of the dispersibility reducing agent include alkyl esters of lactic acid such as methyl lactate, ethyl lactate, and propyl lactate, alkyl ethers of polyhydric alcohols such as methyl ether, ethyl ether, butyl ether, and hexyl ether. The property reducing agent is preferably at least one selected from the group consisting of alkyl esters of lactic acid and alkyl ethers of polyhydric alcohol ethers, more preferably alkyl esters of lactic acid, and even more preferably ethyl lactate. Thereby, the reliability of the conductor pattern 20 can be made higher.

  The content of the dispersibility reducing agent in the dispersibility reducing agent-containing composition (dispersibility reducing agent-containing ink) 300 is not particularly limited, but is preferably 10 wt% or more and 80 wt% or less, and is preferably 20 wt% or more and 40 wt%. The following is more preferable. As a result, the function of the dispersibility reducing agent can be exhibited more effectively, the efficiency of this step is particularly excellent, and the productivity of the wiring board (ceramic circuit board) 30 is particularly excellent. be able to.

[Other ingredients]
The dispersibility reducing agent-containing composition (dispersion reducing agent-containing ink) 300 may contain components other than the dispersibility reducing agent.
Examples of such components include a liquid medium for dissolving and / or dispersing a dispersibility reducing agent, a drying inhibitor, a surface tension adjuster, a pH adjuster, and an antiseptic.

Examples of the liquid medium include alcohol solvents such as water, methanol, ethanol, butanol, propanol and isopropanol, ether solvents such as 1,4-dioxane and tetrahydrofuran (THF), various aromatic heterocyclic compound solvents, Examples thereof include nitrile solvents such as acetonitrile and aldehyde solvents such as acetaldehyde, but the main solvent is preferably water because it is easy to handle.
When such components (hereinafter referred to as “other components”) are included, the content of other components in the dispersibility-reducing agent-containing composition (dispersion-reducing agent-containing ink) 300 is 20 wt% or more and 90 wt% or less. Is preferred.

  The dispersibility-reducing agent-containing composition (dispersibility-reducing agent-containing ink) 300 may be applied to the entire surface of the ceramic molded body 15 provided with the conductor pattern precursor 10, or the conductor pattern precursor 10. May be applied to a part of the surface of the ceramic molded body 15 provided with a conductive pattern, but is preferably applied selectively to the region to which the conductive pattern forming ink 200 is applied. Thereby, the usage-amount of the dispersibility reducing agent containing composition (dispersion reducing agent containing ink) 300 can be suppressed, and the production cost of the wiring board 30 can be suppressed.

  The dispersibility reducing agent-containing composition (dispersion reducing agent-containing ink) 300 may be applied by any method, but it is preferably applied by a droplet discharge method. Thereby, the position selectivity at the time of providing the dispersibility reducing agent containing composition (dispersibility reducing agent containing ink) 300 can be made more excellent, and formation of the fine conductor pattern 20 more suitably. It can be carried out.

When applying the dispersibility-reducing agent-containing composition (dispersibility-reducing agent-containing ink) 300 by the droplet discharge method, this step is the same using the same ink jet apparatus as described in the conductor pattern precursor forming step. Can be performed under the following conditions.
As described above, in the present invention, a conductive pattern forming ink set including the dispersibility-reducing agent-containing ink and the conductive pattern forming ink as described above is used for forming a conductive pattern (manufacturing a wiring board). This reduces the amount of dispersibility-reducing agent used, reduces the production cost of wiring boards, and prevents the occurrence of cracks, disconnections, short circuits, etc., and has a highly reliable conductor pattern. A wiring board can be provided.
Through the above steps, the conductor pattern 20 of the present embodiment can be formed thicker than a conductor pattern formed by a conventional ink. More specifically, a film having a thickness of 5 μm or more can be formed.

(Lamination process)
Next, the PET film is peeled off from these ceramic green sheets 15 and these are laminated to obtain a laminate 17.
At this time, the ceramic green sheets 15 to be laminated are arranged so that the precursors 10 are connected via the conductor posts 16 between the ceramic green sheets 15 stacked one above the other as necessary.
Thereafter, the ceramic green sheets 15 are pressure-bonded to each other while being heated to a glass transition point or higher of the binder constituting the ceramic green sheets 15. Thereby, the laminated body 17 is obtained.

(Baking process)
When the laminated body 17 is formed in this way, for example, heat treatment (firing treatment) is performed by a belt furnace or the like. Thereby, each ceramic green sheet 15 is sintered to become a ceramic substrate 31, and the precursor 10 is composed of a wiring pattern or an electrode pattern by sintering silver particles (metal particles) constituting the ceramic substrate 31. A circuit (conductor pattern) 20 is obtained. And the laminated body 17 becomes the laminated substrate 32 by heat-processing the laminated body 17 in this way.

  Here, the heating temperature (firing temperature) of the laminated body 17 is preferably not less than the softening point of the glass contained in the ceramic green sheet 15, and specifically, not less than 600 ° C and not more than 900 ° C. preferable. As heating conditions, the temperature is raised and lowered at an appropriate rate, and the maximum heating temperature, that is, the temperature of 600 ° C. to 900 ° C. is maintained for an appropriate time according to the temperature. To do.

  Thus, the glass component of the ceramic substrate 31 obtained can be softened by raising the heating temperature to a temperature equal to or higher than the softening point of the glass, that is, the temperature range. Therefore, after cooling to room temperature and curing the glass component, the ceramic substrate 31 constituting the laminated substrate 32 and the circuit (conductor pattern) 20 are more firmly fixed.

In particular, the ceramic substrate 31 obtained by heating at a temperature of 900 ° C. or lower becomes a low-temperature fired ceramic (LTCC).
Here, the metal particles constituting the conductor pattern precursor 10 provided on the ceramic green sheet 15 are fused to each other by heat treatment and become conductive by being continuous.

  By such heat treatment, the circuit 20 is directly connected to the contact 33 in the ceramic substrate 31 and made conductive. Here, if the circuit 20 is merely placed on the ceramic substrate 31, the mechanical connection strength to the ceramic substrate 31 is not ensured, and therefore there is a possibility that the circuit 20 may be damaged by an impact or the like. However, in this embodiment, as described above, the circuit 20 is firmly fixed to the ceramic substrate 31 by once softening the glass in the ceramic green sheet 15 and then curing it. Therefore, the formed circuit 20 has a high mechanical strength.

In such a method of manufacturing the ceramic circuit board 30, the conductive pattern forming ink 200 is applied to the ceramic green sheet 15 as described above, particularly when the ceramic substrates 31 constituting the multilayer substrate 32 are manufactured. Thus, the conductor pattern 20 having a desired shape can be reliably formed with high accuracy.
Therefore, according to the present invention, it is possible not only to meet the demand for miniaturization of electronic components that are components of electronic equipment, but also to fully meet the needs for high-mix low-volume production.

  Moreover, since the heating temperature at the time of heat-treating the ceramic green sheet 15 is set to be equal to or higher than the softening point of the glass contained in the ceramic green sheet 15, the ceramic green sheet 15 is formed when the ceramic green sheet 15 is made into the ceramic substrate 31 by heat treatment. The softened glass of the conductor pattern 20 is firmly fixed on the ceramic substrate 31 (ceramic green sheet 15), and therefore the mechanical strength of the conductor pattern 20 can be increased.

<< Conductor pattern and wiring board >>
Next, the conductor pattern and wiring board obtained by using the method as described above will be described.
The wiring board (ceramic circuit board) 30 is formed on a laminated board 32 in which a large number (for example, about 10 to 20 pieces) of ceramic boards 31 are laminated, and an outermost layer of the laminated board 32, that is, a surface on one side. In addition, the circuit 20 is formed of a fine wiring or the like.

The laminated substrate 32 includes a conductor pattern (circuit) 20 formed by the conductor pattern precursor 10 between the laminated ceramic substrates 31 and 31.
The conductor pattern 20 is a thin-film conductor pattern formed by heating (sintering) the conductor pattern precursor 10 as described above, and is formed by bonding silver particles to each other, and at least the conductor pattern 20. The silver particles are bonded to each other without a gap on the surface.

The specific resistance of the conductor pattern 20 is preferably less than 20 μΩcm, and more preferably 15 μΩcm or less. The specific resistance at this time refers to the specific resistance after heating and drying at 160 ° C. after ink application. When the specific resistance is 20 μΩcm or more, it becomes difficult to use it for applications requiring electrical conductivity, that is, for electrodes formed on a circuit board.
The conductor pattern 20 as described above is used for high-frequency modules, interposers, MEMS (Micro Electro Mechanical Systems), acceleration sensors, surface acoustic wave elements, antennas, comb electrodes, and the like of mobile telephones such as mobile phones and PDAs. The present invention can be applied to deformed electrodes and other electronic parts such as various measuring devices.

In addition, a contact (via) 33 connected to the circuit 20 is formed on the ceramic substrate 31. With such a configuration, the circuit 20 is electrically connected by the contact 33 between the circuits 20 and 20 arranged above and below.
The wiring board 30 as described above is an electronic component used in various electronic devices, such as circuit patterns composed of various wirings and electrodes, multilayer ceramic capacitors, multilayer inductors, LC filters, composite high frequency components, and the like. Is formed on a substrate.

As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to these.
For example, in the above-described embodiment, the case where a colloidal liquid is used as the conductor pattern forming ink has been representatively described.
In the above-described embodiment, the conductor pattern forming ink is described as having silver particles dispersed therein, but may be other than silver. As a metal which comprises a metal particle, silver, copper, palladium, platinum, gold | metal | money, or these alloys etc. are mentioned, for example, These can be used 1 type or in combination of 2 or more types. When the metal particles are an alloy, the metal is mainly used, and an alloy containing another metal may be used. Moreover, the alloy which the said metals mixed with arbitrary ratios may be sufficient. Further, mixed particles (for example, particles in which silver particles, copper particles, and palladium particles are present in an arbitrary ratio) may be dispersed in a liquid. Since these metals have a low resistivity and are stable and are not oxidized by heat treatment, it is possible to form a stable conductor pattern with a low resistance by using these metals.

Further, in the above-described embodiment, the case where the conductive pattern forming ink includes an aqueous dispersion medium as a dispersion medium for dispersing the metal particles has been representatively described. However, as the dispersion medium, water and / or a phase with water is used. A non-aqueous dispersion medium (oil-based dispersion medium) that is a liquid having poor solubility (for example, a liquid having a solubility in 100 g of water at 25 ° C. of less than 30 g) may be included.
Further, for example, in the above-described embodiment, the piezo method is used as the droplet discharge method. However, the present invention is not limited to this, and for example, a method of discharging ink by bubbles generated by heating the ink is known. Various techniques can be applied.

Next, specific examples of the present invention will be described.
Example 1
[1] Preparation of conductive pattern forming ink set [1-1] Preparation of conductive pattern forming ink 3 mL of 10N-NaOH aqueous solution was added to alkalinize 50 mL of water, 17 g of trisodium citrate dihydrate, tannin 0.36 g of acid was dissolved. To the obtained solution, 3 mL of 3.87 mol / L silver nitrate aqueous solution was added and stirred for 2 hours to obtain a silver colloid solution. The obtained silver colloid solution was desalted by dialysis until the electrical conductivity was 30 μS / cm or less. After dialysis, the coarse metal colloid particles were removed by centrifugation at 3000 rpm for 10 minutes.

  To this silver colloid liquid, triethanolamine shown in Table 1 as a drying inhibitor, urea, xylitol, polyglycerin as an organic binder, and Surfynol 104PG-50 as a surface tension regulator (Nisshin Chemical Industry) Co., Ltd.) and Olfin EXP4036 (manufactured by Nissin Chemical Industry Co., Ltd.) and ion-exchanged water for concentration adjustment were added to obtain a conductor pattern forming ink.

[1-2] Preparation of Dispersibility Reducing Agent-Containing Ink On the other hand, ethyl lactate as a dispersibility reducing agent, water, glycerin as a humectant, and Surfynol 104PG-50 (manufactured by Nissin Chemical Industry Co., Ltd.) as a surface tension modifier. And Olfine EXP4036 (manufactured by Nissin Chemical Industry Co., Ltd.) were mixed to obtain a dispersibility reducing agent-containing ink.
As a result, a conductor pattern forming ink set composed of the conductor pattern forming ink and the dispersibility reducing agent-containing ink was obtained.

[2] Production of Ceramic Green Sheet (Ceramic Molded Body) First, alumina (Al ₂ O ₃ ) powder having an average particle diameter of 1.5 μm as ceramic powder and oxidation having an average particle diameter of 1.5 μm as ceramic powder Titanium (TiO ₂ ) powder and borosilicate glass powder having an average particle size of 1.5 μm as glass powder were mixed to obtain a mixed powder.

  Next, a slurry was obtained by adding polyvinyl butyral as a binder (binder) and dibutyl phthalate as a plasticizer to the mixed powder, and mixing and stirring. Next, the slurry is formed into a sheet shape on a PET film with a doctor blade, and this is cut into a square shape with a side length of 200 mm to obtain a ceramic green sheet (ceramic molded body). (Ceramic molded body preparation process).

[3] Production of Ceramic Circuit Board Next, the ink for forming a conductor pattern was put into an ink jet apparatus as shown in FIGS. 2 and 3, respectively.
Next, the temperature of the ceramic green sheet (ceramic molded body) placed on the table of the inkjet apparatus was raised to 60 ° C. Thereafter, 15 ng droplets per droplet were sequentially discharged from each discharge nozzle, and 20 lines (conductor pattern precursor) having a line width of 25 μm, a thickness of 20 μm, and a length of 10.0 cm were drawn. The distance between each line was 5 mm. And the ceramic green sheet in which this line was formed was put into the drying furnace, and it dried by heating for 15 minutes at 60 degreeC (conductor pattern precursor formation process).

The ceramic green sheet on which the line was formed as described above was used as the first ceramic green sheet.
Next, through holes with 100 μm in diameter are formed in a total of 40 locations by punching another ceramic green sheet with mechanical punches or the like at both ends of the above metal wiring, and filling with a conductive pattern forming ink. A contact (via) was formed. Further, a 2 mm square pattern was formed on this contact (via) as a terminal portion by discharging the conductor pattern forming ink using the droplet discharge device.

The ceramic green sheet on which this terminal portion was formed was used as the second ceramic green sheet.
Next, the dispersibility-reducing agent-containing ink was mounted on a droplet discharge device as shown in FIGS. Next, droplets of the dispersibility-reducing agent-containing ink were sequentially discharged from each discharge nozzle of the droplet discharge device toward the first ceramic green sheet (dispersibility reducing agent applying step). Application of the dispersibility-reducing agent-containing ink to the first ceramic green sheet was performed in a pattern corresponding to the conductor pattern precursor formed using the conductor pattern forming ink. And the ceramic green sheet in which this line was formed was put into a drying furnace, and it heated and dried at 60 degreeC for 15 minutes.

Next, the first ceramic green sheet was laminated under the second ceramic green sheet, and two unprocessed ceramic green sheets were laminated as a reinforcing layer to obtain a raw laminate (lamination process). Twenty such raw laminates were produced.
Next, these raw laminates were pressed at a temperature of 95 ° C. at a pressure of 250 kg / cm ² for 30 seconds, and then heated in the atmosphere at a heating rate of 66 ° C./hour for about 6 hours, with a heating rate of 10 Sintered according to a sintering profile such as holding at a maximum temperature of 890 ° C. for 30 minutes through a temperature rising process in which the temperature is continuously increased, such as about 5 hours at a temperature / hour and about 4 hours at a temperature rising rate of 85 ° C./hour, A ceramic circuit board was obtained (firing process).

(Examples 2 to 6)
A conductive pattern forming ink was prepared in the same manner as in Example 1 except that the types and amounts of materials used for preparing the conductive pattern forming ink were as shown in Table 1. A dispersibility reducing agent-containing ink is prepared in the same manner as in Example 1 except that the types and amounts of materials used for the preparation are shown in Table 1, and used for the production of ceramic green sheets (ceramic molded bodies). A ceramic circuit board was prepared in the same manner as in Example 1 except that a ceramic green sheet (ceramic molded body) was produced in the same manner as in Example 1 except that the types and amounts of materials used were as shown in Table 2. Manufactured.
(Comparative Example 1)
A ceramic circuit board was produced in the same manner as in Example 1 except that the dispersibility reducing agent application step was omitted.

  The blending amount of each constituent material of the conductive pattern forming ink for each of the above Examples and Comparative Examples is shown in Table 1, the blending amount of each constituent material of the dispersibility reducing agent-containing ink is shown in Table 1, and each of the above Examples Table 2 shows the amount of each constituent material of the ceramic green sheet for the comparative example. In the table, triethanolamine is shown as TEA, monoethanolamine as MEA, diethanolamine as DEA, urea as Ur, xylitol as Xyl, and sorbitol as Sor. In addition, the viscosity of the conductive pattern forming ink for each of the above Examples (viscosity at 25 ° C. measured according to JIS Z8809 using a vibration viscometer) is 3 mPa · s or more and 8 mPa · s or less. The value was within the range. Further, the viscosity of the dispersibility-reducing agent-containing ink for each of the Examples (viscosity at 25 ° C. measured according to JIS Z8809 using a vibration viscometer) is 3 mPa · s or more and 8 mPa · s. The value was within the range of s or less. In addition, the dispersibility reducing agent constituting the dispersibility reducing agent-containing ink used in each of the above examples is 24 hours after adding and mixing only 10 parts by weight with respect to 100 parts by weight of conductive pattern forming ink. When elapsed, the median particle diameter (Dv50) by the dynamic light scattering particle size distribution meter of the metal particles is more than three times that before addition and mixing, and the absorbance by the UV spectrophotometer (due to plasmon absorption of Ag nanoparticles) ) Satisfies the condition of 0.4 times or less before addition and mixing.

[4] Evaluation of ceramic circuit board (conduction reliability)
For each ceramic circuit board obtained in each of the above examples and comparative examples, a tester is applied between the terminal portions formed on the 20 conductor patterns, and the presence or absence of conduction is confirmed. What was confirmed to be conductive was regarded as a non-defective product assuming that the conductivity was 100%. The conductivity for each ceramic circuit board is obtained by dividing the number of conductive patterns (X) with conduction by the number of formed conductive patterns (20) ((X / 20) × 100 [%]) The sintering stability was evaluated according to the following evaluation criteria.

A: The conductivity was 100% in all 20 ceramic circuit boards.
B: There were 15 or more ceramic circuit boards having a conductivity of 100%, and other ceramic circuit boards also had a conductivity of 95% or more.
C: There were 10 to 14 ceramic circuit boards having a conductivity of 100%, and other ceramic circuit boards also had a conductivity of 95% or more.
D: There were 5 to 9 ceramic circuit boards having a conductivity of 100%, and other ceramic circuit boards also had a conductivity of 95% or more.
E: There were 1 to 4 ceramic circuit boards having a conductivity of 100%, and other ceramic circuit boards also had a conductivity of 95% or more.
F: Conductivity was 95% or more and less than 100% in all 20 ceramic circuit boards.
G: Conductivity was less than 95% in all 20 ceramic circuit boards.

[5] Adhesiveness of conductor pattern to ceramic substrate For each of the examples and comparative examples, the same as above except that the formation pattern (drawing pattern) of the conductor pattern precursor was changed as follows and the lamination step was omitted. The ceramic substrate corresponding to the first ceramic green sheet (having the conductor pattern) described above was obtained.
The conductor pattern precursor was formed as a film by sequentially drawing 200 lines having a line width of 25 μm, a thickness of 20 μm, and a length of 10.0 cm at intervals of 0.
In accordance with JIS K5600, the cross-cut method was used for evaluation according to the following four-stage criteria to evaluate the adhesion between the conductor pattern and the substrate.

A: There is no peeling.
B: The portion where the blade is inserted is notched.
C: Slight peeling occurs.
D: Peeled.
These results are shown in Table 3.

  As is clear from Table 3, in the present invention, the ceramic circuit board showed excellent conductivity. Further, the conductor pattern had high adhesion to the ceramic substrate and was particularly highly reliable. On the other hand, in the comparative example, a satisfactory result was not obtained.

  DESCRIPTION OF SYMBOLS 10 ... Conductor pattern precursor (precursor) 15 ... Ceramics green sheet (ceramic molding) 16 ... Conductor post (contact precursor) 17 ... Laminated body 20 ... Conductor pattern (circuit) 30 ... Ceramic circuit board (wiring board) 31 DESCRIPTION OF SYMBOLS ... Ceramic substrate 32 ... Multilayer substrate 33 ... Contact 100 ... Inkjet device (droplet ejection device) 110 ... Inkjet head (droplet ejection head, head) 111 ... Head body 112 ... Vibration plate 113 ... Piezo element 114 ... Body 115 ... Nozzle Plate 115P ... Ink ejection surface 116 ... Reservoir 117 ... Ink chamber 118 ... Nozzle (protrusion) 130 ... Base 140 ... Table 170 ... Table positioning means 171 ... First moving means 172 ... Motor 180 ... Head positioning means 181 ... Second moving means 182 ... Linear motor 183, 184, 185 ... Motor 190 ... Control device 191 ... Drive circuit 200 ... Ink for forming a conductor pattern (ink) 300 ... Composition containing dispersibility reducing agent (containing dispersibility reducing agent) Ink) S ... Base material

Claims (9)

A ceramic molded body preparation step of preparing a sheet-shaped ceramic molded body made of a material including a ceramic material and a binder;
A conductor pattern precursor forming step of forming a conductor pattern precursor by discharging a conductive pattern forming ink containing metal particles and a dispersion medium in which the metal particles are dispersed to the ceramic molded body by a droplet discharge method;
Dispersibility in which a composition containing a dispersibility reducing agent that reduces the dispersibility of the metal particles in the conductive pattern forming ink is applied to at least a portion of the ceramic molded body to which the conductive pattern forming ink is applied. A reducing agent application step;
A laminating step of laminating a plurality of the ceramic molded bodies to obtain a laminated body;
A method of manufacturing a wiring board, comprising: sintering the laminated body to obtain a wiring board having a conductor pattern and a ceramic substrate.   The method for manufacturing a wiring board according to claim 1, wherein the composition containing the dispersibility-reducing agent is selectively applied to the region to which the conductive pattern forming ink is applied.   The method for manufacturing a wiring board according to claim 1, wherein the application of the composition containing the dispersibility reducing agent is performed by a droplet discharge method.   4. The method for manufacturing a wiring board according to claim 1, wherein the dispersibility reducing agent is at least one selected from the group consisting of alkyl esters of lactic acid and alkyl ethers of polyhydric alcohols.   The method for manufacturing a wiring board according to claim 1, wherein the conductive pattern forming ink contains a polyglycerin compound.   The method for manufacturing a wiring board according to claim 1, wherein the ceramic molded body contains polyvinyl butyral as the binder.   The method for manufacturing a wiring board according to claim 1, wherein the conductive pattern forming ink contains an aqueous dispersion medium as the dispersion medium. A conductor pattern forming ink set for forming a conductor pattern by patterning on a substrate,
A conductive pattern forming ink comprising metal particles and a dispersion medium in which the metal particles are dispersed;
A conductive pattern forming ink set comprising: a dispersibility reducing agent-containing ink containing a composition containing a dispersibility reducing agent that reduces dispersibility of the metal particles in the conductive pattern forming ink.   A wiring board manufactured using the method according to claim 1.

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