JP2012160562A - Manufacturing method of wiring board, ink set for forming conductor pattern, and wiring board - Google Patents

Abstract

To provide a manufacturing method capable of efficiently manufacturing a highly reliable wiring board provided with a highly reliable conductor pattern in which occurrence of cracks, disconnections, short circuits and the like is prevented.
A ceramic molded body preparing step of preparing a sheet-shaped ceramic molded body 15 made of a material including a ceramic material and a binder and containing an acid or a base at least in the vicinity of the surface, and the ceramic molded body 15 A conductive pattern precursor forming step of forming a conductive pattern precursor 10 by discharging a conductive pattern forming ink 200 containing metal particles and an organic component to a region containing the acid or base by a droplet discharge method; And laminating the ceramic molded body 15 to obtain a laminated body 17 and sintering the laminated body 17 to obtain a wiring substrate 32 having a conductor pattern 20 and a ceramic substrate 31.
[Selection] Figure 1

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, miniaturization of wiring (for example, wiring with a line width of 60 μm or less) and high density circuit boards by narrowing the pitch have been demanded. It is disadvantageous for pitching and it is difficult to meet the above requirements. 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).

  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 2007-084387 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 producing a wiring board according to the present invention comprises a ceramic molded body preparation step comprising a sheet-shaped ceramic molded body comprising a material containing a ceramic material and a binder, and containing at least part of the surface and containing an acid or a base,
A conductor pattern precursor forming step of forming a conductor pattern precursor by discharging a conductive pattern forming ink containing metal particles and an organic component to a region containing the acid or base of the ceramic molded body by a droplet discharge method; ,
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 according to the present invention, the ceramic molded body imparts a composition containing an acid or a base to a temporary molded body obtained by molding a composition containing the ceramic material and the binder. It is preferable that it is obtained by this.
Thereby, the composition containing an acid or a base can be selectively applied only to a part of the surface of the temporary molded body, for example, to a region where a conductor pattern is to be formed. As a result, the amount of acid or base used can be suppressed, and the production cost of the wiring board can be suppressed.

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

In the method for manufacturing a wiring board according to the present invention, the ceramic molded body is preferably obtained by molding a composition containing an acid or a base in addition to the ceramic material and the binder.
Thereby, the productivity of the wiring board can be made particularly excellent.
In the method for producing a wiring board according to the present invention, the conductor pattern forming ink comprises a water-soluble polysaccharide having a weight average molecular weight of 1,000 or more and 5,000 or less, and a polyglycerol compound having a polyglycerol skeleton, Furthermore, it is preferable to include it.
As a result, it is possible to more effectively prevent disconnection of the formed conductor pattern while improving the discharge stability of the ink droplets for forming the conductor pattern, and to improve the reliability of the manufactured wiring board. Can be made particularly excellent.

In the method for manufacturing a wiring board according to the present invention, it is preferable that the conductive pattern forming ink contains maltodextrin that is solid at room temperature as the polysaccharide.
Thereby, the discharge stability of the droplets and the reliability of the manufactured wiring board can be made particularly excellent.
In the method for manufacturing a wiring board of the present invention, it is preferable that the conductor pattern forming ink contains a polysaccharide having a carbonyl group reduced as the polysaccharide.
Thereby, the discharge stability of the droplets and the reliability of the manufactured wiring board can be made particularly excellent.

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 the manufactured wiring board can be made particularly excellent.
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 an organic component;
And an acid-base-containing ink containing an acid or a base.
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 1st 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 (droplet discharge apparatus). It is a schematic diagram for demonstrating schematic structure of an inkjet head (droplet discharge head). It is sectional drawing which shows 2nd Embodiment of the manufacturing method of the wiring board (ceramics circuit board) of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.
<Method for manufacturing wiring board>
[First Embodiment]
First, a first embodiment of a method for manufacturing a wiring board according to the present invention will be described.
FIG. 1 is a cross-sectional view showing a first 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 for 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 containing an acid or a base in addition to 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 an organic component on at least one surface of the molded body 15 by a droplet discharge method (conductor pattern precursor 10). Forming step), a step of laminating a plurality of ceramic molded bodies 15 to obtain a laminate 17 (lamination step), and heating the laminate 17 to obtain a wiring substrate 30 having a conductor pattern 20 and a ceramic substrate 31. A process (firing process).

(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 an acid or a base in addition to the ceramic material and the 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.
A ceramic powder (ceramic material) having an average particle size of 0.1 μm or more and 10 μm or less and a glass powder having an average particle size of 0.1 μm or more and 10 μm or less are prepared, and these are mixed at an appropriate mixing ratio, for example, a weight of 1: 1. Can be mixed in a ratio.

Such ceramic _{materials, Al 2 O 3, SiO 2} , MgO, MgO · SiO 2, 2MgO · SiO 2 and _{TiO 2, BaTiO 3, Ba x} Sr 1-x TiO 3, SrTiO 3, CaTiO 3, PbZr _x Ti _1-x , Pb _1-x La _y ZrTi _1-x O ₃ , SrBi ₂ TaO ₃ and other composite oxides and other ferroelectric materials having a perovskite structure, or MgTiO ₃ , Ba (Mg _{1 / 3} Ta _2/3 ) O ₃ , Ba (Zn _1/3 Ta _2/3 ) O ₃ , Ba (Ni _1/3 Ta _2/3 ), Ba (Co _1/3 Ta _2/3 ), BaNd ₂ Ti ₄ O ₁₂ , Ba ₂ Ti ₉ O ₂₀ , LaAlO ₃ , PrAlO ₃ , SmAlO ₃ , YAlO ₃ , GdAlO ₃ , DyAlO ₃ , ErAlO ₃ , Sr (Zn _1/3 Ta _2/3 ) O ₃ , Sr (Ni _1/3 Ta _2/3 ) O ₃ , Sr (Co _1/3 Ta _2/3 ) O ₃ , Sr (Mg _1/3 Ta _2/3 ) O ₃ , Sr (Ca _1/3 Ta _2/3 ) O ₃ , Ba ₂ Ti ₉ O ₂₀ , Ba (Co _1/3 Nb _2/3 ) O ₃ etc. Although it is possible, any general ceramic material can be used.

As the glass component, either a crystallized glass or an amorphous glass can be used as long as it is a general glass. Examples thereof include those containing SiO ₂ , Al ₂ O ₃ , RO (R is Mg, Ca, Sr, Ba), and specifically include SiO ₂ —BaO series, SiO ₂ —Al ₂ O ₃ —BaO. , SiO ₂ —Al ₂ O ₃ —BaO—B ₂ O ₃ system, SiO ₂ —Al ₂ O ₃ —BaO—ZnO—B ₂ O ₃ system glass, Bi glass, and glass containing them as a main component Etc. are available.
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 can be suitably used. Polyvinyl butyral 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 acid or base can be reliably held near the surface of the ceramic molded body, and the function of the acid or base as described in detail later can be more effectively exhibited. it can. As a result, the reliability of the finally obtained wiring board 30 (formed conductor pattern 20) can be made higher.

  In addition, as the binder, acrylic resins (acrylic acid, methacrylic acid or homopolymers or copolymers thereof, specifically, acrylic ester copolymers, methacrylic ester copolymers, acrylic ester- Methacrylic acid ester copolymer and the like) can be preferably used. The acrylic resin is insoluble in water and easily dissolved or swelled in a so-called oil-based organic solvent. In addition, by using an acrylic resin as a binder, the acid or base can be reliably held in the vicinity of the surface of the ceramic molded body 15, and the function of the acid or base as described in detail later is more effectively exhibited. Can be made. As a result, the reliability of the finally obtained wiring board 30 (formed conductor pattern 20) can be made higher. In addition, those conventionally used for ceramic green sheets can be used. For example, a homopolymer or copolymer such as polyvinyl alcohol, acrylic-styrene, polypropylene carbonate, or cellulose may be used. it can.

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.
And the ceramic molded object 15 formed at this process contains an acid or a base.
As described above, since the ceramic molded body 15 contains an acid or a base, when the conductor pattern forming ink 200 is applied to the ceramic molded body 15 in the conductor pattern precursor forming step, which will be described in detail later, a conductor pattern is formed. The ink 200 can be brought into contact with the acid or base contained in the ceramic molded body 15. As a result, the organic component contained in the conductor pattern forming ink 200 is easily decomposed in the subsequent firing step, and the organic component burns incompletely and is carbonized by a reaction such as intramolecular dehydration and flame retardant. It is possible to surely prevent the formation of carbon. As a result, foaming or the like of the conductor pattern precursor 10 in the firing process can be prevented, and the finally formed conductor pattern 20 can be reliably formed having a desired shape, and carbon can be formed in the conductor pattern 20. Can be reliably prevented, and the conductivity of the conductor pattern 20 can be stabilized. As a result, the reliability of the finally manufactured wiring board 30 can be made sufficiently excellent.

  The excellent effects as described above can be obtained by previously containing an acid or a base in the ceramic molded body to which the ink for forming a conductor pattern is applied. This cannot be obtained when the forming ink contains an acid or a base. That is, when an acid or a base is contained in the conductor pattern forming ink, the organic component is denatured and deteriorated during storage of the conductor pattern forming ink, and the organic component originally has. It is difficult to fully perform the functions. In addition, problems such as a drop in the ejection stability of the conductive pattern forming ink droplets also occur.

In particular, in this embodiment, the ceramic molded body 15 is obtained by molding a composition containing an acid or a base in addition to a ceramic material and a binder, so that the productivity of the wiring board 30 is particularly excellent. Can be.
In the present invention, examples of the acid or base include hydrogen chloride, nitric acid, sulfuric acid, perchloric acid, chloric acid, chlorous acid, hypochlorous acid, and other inorganic acids, acetic acid, oxalic acid, propionic acid, butyric acid, valeric acid, Organic acids such as adipic acid, salicylic acid, gallic acid, phthalic acid, aspartic acid, glutamic acid, inorganic bases such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, ammonia, sodium carbonate, sodium bicarbonate, aniline Organic bases such as trimethylamine, toluethylamine, diethylamine, ethanolamine, diethanolamine, triethanolamine, aminopropanol, ethylenediamine, histidine, lysine, arginine, polyethyleneimine, and polyaminopyridine can be used. Among them, an acid / base having a molecular weight of 150 or less is preferable, and an acid / base having a molecular weight of 110 or less is more preferable. The acid is more preferably hydrogen chloride and / or acetic acid, and the base is more preferably one or more selected from the group consisting of ammonia, trimethylamine, toluethylamine and diethylamine. As a result, it is possible to reliably prevent the acid or base from remaining in the finally obtained wiring board while more effectively exerting the functions of the acid and base as described above in the manufacturing process of the wiring board. it can.

  When the ceramic molded body 15 is obtained by molding a composition containing a ceramic material, a binder, and an acid or a base as in this embodiment, the acid or base in the ceramic molded body 15 is obtained. The content is preferably 0.3 wt% or more and 10 wt% or less, and more preferably 0.5 wt% or more and 5 wt% or less. When the acid or base content is within the above range, the above-described effects are more remarkably exhibited.

In the present embodiment, in the preparation of the slurry, the acid or base is mixed and stirred with the raw material powder together with the binder and the like.
A ceramic molded body (green sheet) 15 is obtained by forming the slurry as described above into a sheet shape.
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 (hereinafter also simply referred to as “ink”) 200 as described in detail later is dropped on 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 by a 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. Among these, water is particularly preferable.
The content of the aqueous dispersion medium in the conductor pattern forming ink 200 is preferably 20 wt% or more and 80 wt% or less, and more preferably 25 wt% or more and 70 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.
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, etc. are oxidatively 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.

  The conductive pattern forming ink 200 contains an organic component together with the above-described silver particles (metal particles). By including such an organic component, for example, the aggregation of silver particles in the conductor pattern precursor 10 described later in detail is prevented, or the metal particles constituting the conductor pattern precursor 10 flow out to unintentional sites. It can be surely prevented, unintentional volatilization of the aqueous dispersion medium in the conductor pattern forming ink 200 can be prevented, or the droplet discharge stability of the conductor pattern forming ink 200 can be made excellent. . Examples of such an organic component include those described in detail below. Conventionally, in the method of manufacturing a wiring board using an ink jet method, the conductor pattern is cracked and the specific resistance is increased. There is a problem that disconnection and short circuit may occur, and there is a problem that it is difficult to sufficiently increase the reliability and yield of the conductive pattern (wiring board) to be formed. It has been found that such a problem is due to the fact that the organic component is difficult to remove promptly and reliably in the manufacturing process of the wiring board, and has arrived at the present invention.

Hereinafter, the organic components constituting the conductor pattern forming ink 200 will be described in detail.
[Polysaccharide]
The ink for forming a conductor pattern according to the present invention preferably contains a water-soluble polysaccharide having a weight average molecular weight of 1,000 or more and 5,000 or less. By including such a polysaccharide together with a polyglycerin compound, which will be described in detail later, the discharge stability of the conductive pattern forming ink droplets is made particularly excellent, while the conductor pattern to be formed is disconnected. This can be prevented more effectively, and the reliability of the manufactured wiring board can be made particularly excellent.

The conductive pattern forming ink preferably contains a polysaccharide that is solid at room temperature (25 ° C.). Thereby, the reliability of the conductor pattern formed can be made especially excellent.
The weight average molecular weight of the polysaccharide is from 1,000 to 5,000, preferably from 1,200 to 4,500, more preferably from 1,500 to 4,000. . Thereby, the effects as described above are more remarkably exhibited.

  Examples of the polysaccharide include cellulose, guar gum, starch (amylose, amylopectin), pullulan, dextrin, fructan, glucomannan, agarose, agaropectin, carrageenan, chitin, chitosan, pectin, alginic acid, hyaluronic acid, maltodextrin, or these Derivatives (for example, polysaccharides in which a carbonyl group is reduced) and the like can be mentioned, and one or more of these can be used in combination.

Among the above, the conductive pattern forming ink preferably contains a solid maltodextrin at room temperature (25 ° C.). Thereby, the discharge stability of the droplet and the reliability of the formed conductor pattern can be made particularly excellent.
In addition, the conductor pattern forming ink preferably contains a polysaccharide having a carbonyl group reduced as the polysaccharide. Thereby, the discharge stability of the droplet and the reliability of the formed conductor pattern can be made particularly excellent.

  The polysaccharide content X (B) in the conductive pattern forming ink is preferably 1.0% by weight or more and 28% by weight or less, more preferably 1.1% by weight or more and 14% by weight or less. More preferably, it is 2.2 wt% or more and 10.5 wt% or less. This makes it possible to more effectively prevent the occurrence of cracks and disconnections while making the ejection stability of the conductor pattern forming ink particularly excellent.

[Polyglycerin compound]
The conductive pattern forming ink preferably contains a polyglycerol compound having a polyglycerol skeleton. By including such a polyglycerin compound together with the polysaccharide as described above, the discharge stability of the ink for forming the conductor pattern is particularly excellent, and the disconnection of the formed conductor pattern is more effective. The reliability of the manufactured wiring board can be made particularly excellent.

  The polyglycerin compound may be any one as long as it has a polyglycerin skeleton (a structure in which a plurality of glycerin molecules are condensed). Examples of the polyglycerin compound include polyglycerin and polyglycerin. And polyglycerin esters such as monostearate, tristearate, tetrastearate, monooleate, pentaoleate, monolaurate, monocaprylate, polycinnolate, sesquistearate, decaoleate, sesquioleate, etc. One kind or a combination of two or more kinds can be used. Among these, as the polyglycerol compound, polyglycerol is preferable. Polyglycerin is particularly excellent in the ability to follow expansion and contraction due to temperature changes of the ceramic molded body to which the conductive pattern forming ink is applied, and more reliably removed from the conductive pattern after the ceramic molded body is sintered. Is a component that can. As a result, the electrical characteristics of the conductor pattern can be made higher. Furthermore, since polyglycerin has high solubility in an aqueous dispersion medium, it can be suitably used.

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

  The content X (A) of the polyglycerol compound in the conductive pattern forming ink is 1.0% by weight or more and 28% by weight or less. This makes it possible to more effectively prevent the occurrence of cracks and disconnections while making the ejection stability of the conductor pattern forming ink particularly excellent. On the other hand, when the content of the polyglycerin compound is less than the lower limit, it is difficult to reliably prevent the occurrence of cracks. On the other hand, if the content of the polyglycerin compound exceeds the upper limit, it becomes difficult to make the viscosity of the conductive pattern forming ink sufficiently low, and the droplet ejection stability is made sufficiently excellent. It becomes difficult.

  As described above, the content X (A) of the polyglycerin compound in the conductor pattern forming ink is 1.0 wt% or more and 28 wt% or less, but 1.1 wt% or more and 14 wt% or less. And is more preferably 2.0 wt% or more and 9.3 wt% or less. Thereby, the effects as described above are more remarkably exhibited. When the conductor pattern forming ink contains two or more components as the polyglycerin compound, the sum of the content ratios of these components is preferably a value within the above range.

  When the content of the polyglycerin compound in the conductor pattern forming ink is X (A) [wt%] and the content of the polysaccharide in the conductor pattern forming ink is X (B) [wt%], X (B A) + X (B) ≦ 28 is preferably satisfied, X (A) + X (B) ≦ 20 is more preferable, and X (A) + X (B) ≦ 15 is satisfied. It is more preferable to satisfy. As a result, the reliability of the formed conductor pattern can be made sufficiently high while the droplet discharge stability is particularly excellent. Moreover, the deformation of the wiring in the pressing process can be suppressed due to the presence of excess organic matter.

  When the content of the polyglycerin compound in the conductive pattern forming ink is X (A) [wt%] and the content of the polysaccharide in the conductive pattern forming ink is X (B) [wt%], 7. It is preferable to satisfy the relationship 5 ≦ X (A) + 4X (B), and it is more preferable to satisfy the relationship 12 ≦ X (A) + 4X (B). As a result, the dimensional accuracy and reliability of the formed conductor pattern can be made particularly excellent while the droplet ejection stability is sufficiently excellent.

  When the content of the polyglycerin compound in the conductive pattern forming ink is X (A) [wt%] and the content of the polysaccharide in the conductive pattern forming ink is X (B) [wt%], 0. It is preferable to satisfy the relationship of 12 ≦ X (A) / X (B) ≦ 12, and it is more preferable to satisfy the relationship of 0 · 20 ≦ X (A) / X (B) ≦ 6. Thereby, the discharge stability of the droplet can be made particularly excellent, and the occurrence of disconnection in the inner layer and the surface layer can be more effectively suppressed.

[Dispersant]
The conductor pattern forming ink preferably contains a dispersant.
The dispersing agent forms silver colloidal particles by adhering to the silver particles. Since such silver colloidal particles are excellent in dispersion stability, the discharge stability of the ink droplets for forming the conductor pattern is more 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, a fine conductor pattern can be more easily formed. Further, silver particles are uniformly distributed in a pattern (conductor pattern precursor) formed with ink, 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 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, a fine conductor pattern can be more easily formed. Further, silver particles are uniformly distributed in a pattern (conductor pattern precursor) formed with ink, 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.

[Other ingredients]
The constituent components of the conductor pattern forming ink are not limited to the above components, and may include components other than those described above.
For example, the conductive pattern forming ink includes polyethylene glycol # 200 (weight average molecular weight 200), polyethylene glycol # 300 (weight average molecular weight 300), polyethylene glycol # 400 (average molecular weight 400), polyethylene glycol # 600 (weight average molecular weight 600). ), Polyethylene glycols such as 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), Polyvinyl alcohol # 200 (weight average molecular weight: 200), polyvinyl alcohol # 300 (weight average molecular weight: 300), polyvinyl alcohol # 400 (flat 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 # 1540 (weight average molecular weight: 1540) and an organic binder such as polyvinyl alcohol such as polyvinyl alcohol # 2000 (weight average molecular weight: 2000).

Further, it may contain a surface tension adjusting agent such as acetylene glycol compound, polyhydric alcohol such as ethylene glycol, 1,3-propanediol, 1,3-butylene glycol, propylene glycol, urea, thiourea, etc. Good.
The viscosity of the conductive pattern forming ink 200 is not particularly limited, but is preferably 2.0 mPa · s or more and 12.0 mPa · s or less, and preferably 5.0 mPa · s or more and 10.0 mPa · s or less. Is more preferable. 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, by adjusting the waveform of the applied voltage generated by the drive circuit 191 to control the ejection conditions of the ink 200, or by controlling the head positioning unit 180 and the table positioning unit 170, the ejection position of the ink 200 onto the substrate S To 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.
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 5.5 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.

In particular, since the ceramic green sheet 15 used in this step contains an acid or a base, the organic component is incompletely combusted in the heat treatment in this step and forms a flame-retardant carbon. Occurrence is reliably prevented.
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.

[Second Embodiment]
Next, a second embodiment of the method for manufacturing a wiring board according to the present invention will be described.
Hereinafter, the manufacturing method of the present embodiment will be described with a focus on differences from the first embodiment described above, and description of similar matters will be omitted.
FIG. 4 is a cross-sectional view showing a second embodiment of a method for manufacturing a wiring board (ceramic circuit board) according to the present invention.

  As shown in FIG. 4, the method of manufacturing a wiring board according to the present embodiment includes a step of preparing a plurality of sheet-like temporary molded bodies 14 obtained by molding a composition containing a ceramic material and a binder (temporary molding). Body preparation step), a step of obtaining a ceramic molded body 15 by applying a composition containing an acid or a base to the temporary molded body 14 (acid-base application step), and at least one surface of the ceramic molded body 15 , A step of forming a conductor pattern precursor 10 by discharging a conductive pattern forming ink 200 containing metal particles and an organic component by a droplet discharge method (conductor pattern precursor forming step), and a plurality of ceramic molded bodies 15 A wiring board 30 having a conductor pattern 20 and a ceramic substrate 31 by heating the laminated body 17 (a lamination process) to obtain the laminated body 17 by laminating layers. And a step (firing step) to obtain. That is, in the first embodiment described above, a ceramic molded body 15 is obtained by molding a composition containing a ceramic material, a binder, and an acid or a base. In the present embodiment, the ceramic material and the binder are A ceramic molded body 15 is obtained by applying a composition containing an acid or a base to the temporary molded body 14. In other words, in this embodiment, the ceramic molded body preparation step includes a temporary molded body preparation step and an acid-base application step. In this way, by obtaining the ceramic molded body 15, a composition containing an acid or a base is selectively formed only on a part of the surface of the temporary molded body 14, for example, in a region where the conductor pattern 20 is to be formed. A region having a high acid or base content can be selectively formed at a specific portion (a part near the surface) of the ceramic molded body 15. As a result, the amount of acid or base used can be suppressed, and the production cost of the wiring board can be suppressed. Further, excessive wetting and spreading of the conductor pattern forming ink 200 on the ceramic molded body 15 can be prevented, and a wiring having a smaller line width can be more suitably formed.

(Temporary molded body preparation process)
In this step, a plurality of sheet-like temporary molded bodies 14 made of a material containing a ceramic material and a binder are prepared.
The temporary molded body 14 can be manufactured in the same manner as the ceramic molded body 15 in the first embodiment described above except that an acid or a base does not have to be used as a raw material.

(Acid base addition step)
In this step, a composition containing an acid or base (acid-base-containing composition) is applied to the surface of at least one side of the temporary molded body 14 to form the acid-base-containing portion 13, and a ceramic green sheet (ceramics) Molded) 15 is obtained.
The acid-base-containing composition applied to the temporary molded body 14 may be liquid, solid, or gaseous. For example, it may be molded into a predetermined shape, but is liquid. Is preferred. Thereby, it is easy to store the acid-base-containing composition, and the application pattern of the acid-base-containing composition can be easily adjusted corresponding to the ceramic green sheet (ceramic molded body) 15 to be formed. In addition, when the acid-base-containing composition is liquid, the viscosity is not particularly limited, but is preferably 2.0 mPa · s or more and 12.0 mPa · s or less, and preferably 5.0 mPa · s or more and 10. More preferably, it is 0 mPa · s or less. Thereby, an acid-base containing composition can be suitably used for droplet discharge as described later.

In the following description, the case where the acid-base-containing composition is a liquid composition (acid-base-containing ink) will be representatively described.
<Acid-base-containing composition (acid-base-containing ink)>
[Acid or base]
The acid or base constituting the acid-base-containing composition (acid-base-containing ink) preferably satisfies the same conditions as described in the first embodiment.

  The pH (hydrogen ion index) of the acid-base-containing composition (acid-base-containing ink) is preferably 2 or more and 5 or less, or 9 or more and 12 or less, and 2.2 or more and 4.8 or less, or 9. More preferably, it is 2 or more and 11.8 or less. As a result, the acid or base can be surely infiltrated near the surface of the temporary molded body 14, the above-described functions can be more effectively exhibited, and the droplet discharge for discharging the acid-base-containing ink can be performed. Problems such as head corrosion can be more effectively prevented.

[Other ingredients]
The acid-base-containing composition (acid-base-containing ink) may contain components other than acid or base.
Examples of such components include water, glycol ethers, glycol esters, glycol acetates, pH adjusters, penetrants, surfactants, and humectants.

When such components (hereinafter referred to as “other components”) are included, the content of other components in the acid-base-containing composition (acid-base-containing ink) is 0.25 wt% or more and 95 wt% or less. Is preferred.
The acid-base-containing composition (acid-base-containing ink) may be applied to the entire surface of the temporary molded body 14 or may be applied to a part of the surface of the temporary molded body 14. However, it is preferable that the conductive pattern forming ink 200 is selectively applied to the region to which the conductive pattern forming ink 200 is applied. Thereby, the usage-amount of an acid or a base can be suppressed and the production cost of a wiring board can be suppressed.

The acid-base-containing composition (acid-base-containing ink) may be applied to the temporary molded body 14 by any method, but is preferably applied by a droplet discharge method. Thereby, the position selectivity at the time of providing the composition containing an acid or a base can be made more excellent, and formation of the fine conductor pattern 20 can be performed more suitably.
When the acid-base-containing composition (acid-base-containing ink) is applied 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 of the first embodiment. Can be performed under the following conditions.

  As described above, in the present invention, the formation of the conductor pattern (production of the wiring board) includes the acid-base-containing ink as described above and the conductor pattern formation ink as described in the first embodiment. Highly reliable conductor pattern that prevents the occurrence of cracks, disconnections, short circuits, etc. while suppressing the amount of acid or base used and the production cost of the wiring board by using the ink set for forming the conductor pattern It is possible to provide a highly reliable wiring board including the above.

<< 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.

In the above-described embodiments, the case where the ink for forming a conductor pattern includes an aqueous dispersion medium as a dispersion medium for dispersing metal particles has been representatively described. However, as the dispersion medium, water and / or a phase with water is used. It may contain a non-aqueous dispersion medium (oil-based dispersion medium (organic 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).
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 conductor pattern forming ink 17 g of trisodium citrate dihydrate and 0.36 g of tannic acid were dissolved in 50 mL of water made alkaline by adding 3 mL of 10N-NaOH aqueous solution. 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.

  In this silver colloid liquid, polyglycerin (weight average molecular weight: 500) as a polyglycerin compound, maltodextrin (weight average molecular weight: 4100) as a polysaccharide, and Surfynol 104PG-50 (day Shinshin Chemical Industry Co., Ltd.) and Olphine EXP4036 (Nisshin Chemical Industry Co., Ltd.) were added, and ion-exchanged water for adjusting the concentration was further added to prepare a conductor pattern forming ink. The maltodextrin as a polysaccharide used for the preparation of the conductor pattern forming ink was solid at room temperature (25 ° C.).

[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 at a weight ratio of 1: 1: 2 to obtain a mixed powder.

Next, polyvinyl butyral (Kuraray Co., Mobital B30T) as a binder (binder), acetic acid as an acid, and di (2-ethylhexyl) phthalate as a plasticizer (manufactured by Shin Nippon Chemical Co., Ltd.) Then, water, ethanol and methyl ethyl ketone as additional dispersion media were added, mixed and stirred to obtain a slurry. The content ratio of water, ethanol, and methyl ethyl ketone in the obtained slurry was 3: 3: 4 by weight.
Next, the slurry is applied in a sheet form on a PET film with a doctor blade so that the coating amount after drying is 35 g / m ^2, and after removing the dispersion medium by drying, A ceramic green sheet (ceramic molded body) was obtained by cutting into a square shape having a length of 200 mm.

(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 the preparation of the conductive pattern forming ink were as shown in Table 1. Ceramic green sheets (ceramic molded bodies) 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 in the production of) were as shown in Table 2.

(Example 7)
[1 ′] Preparation of Conductive Pattern Forming Ink Set First, a conductive pattern forming ink was prepared in the same manner as in Example 1.
On the other hand, acetic acid as an acid, water, and olefin E1010 as a surfactant were mixed to obtain an acid-base-containing ink.
Thus, a conductor pattern forming ink set composed of the conductor pattern forming ink and the acid-base-containing ink was obtained.

[2] Manufacture of ceramic green sheet (ceramic compact) [2-1] Manufacture of temporary compact First, alumina (Al ₂ O ₃ ) powder having an average particle size of 1.5 μm as ceramic powder, and ceramic powder A titanium oxide (TiO ₂ ) powder having an average particle diameter of 1.5 μm and a borosilicate glass powder having an average particle diameter of 1.5 μm as a glass powder are mixed at a weight ratio of 1: 1: 2 and mixed. Further, water as a dispersion medium and Poise 520 (manufactured by Kao Corporation) as a dispersing agent were added to this mixed powder, and dispersed with a mill mixer to obtain an aqueous dispersion.

Next, polyvinyl butyral (manufactured by Kuraray Co., Ltd., Mobital B30T) as a binder (binder), di (2-ethylhexyl) phthalate (manufactured by Nippon Nippon Chemical Co., Ltd.) as a plasticizer, and an additional dispersion Water, ethanol and methyl ethyl ketone as a medium were added and mixed and stirred to obtain a slurry. The content ratio of water, ethanol, and methyl ethyl ketone in the obtained slurry was 3: 3: 4 by weight.
Next, the slurry is applied in a sheet form on a PET film with a doctor blade so that the coating amount after drying is 35 g / m ^2, and after removing the dispersion medium by drying, Was cut into a square shape with a length of 200 mm to obtain a temporary molded body.

[2-2] Application of acid-base-containing ink First, the acid-base-containing ink was mounted on a droplet discharge device as shown in FIGS. Next, droplets of acid-base-containing ink were sequentially discharged from the discharge nozzles of the droplet discharge device toward the temporary formed body to obtain a ceramic green sheet (ceramic formed body). Application of the acid-base-containing ink to the temporary molded body was performed in a pattern corresponding to the conductor pattern precursor to be formed using the conductor pattern forming ink.

(Examples 8 to 13)
A conductor pattern forming ink is prepared in the same manner as in Example 1 except that the types and amounts of materials used for preparing the conductor pattern forming ink are shown in Table 1, and are used for the production of a temporary molded body. A temporary molded body was produced in the same manner as in Example 7 except that the types and amounts of materials used are shown in Table 2, and the types and amounts of materials used for the preparation of the acid-base-containing ink are shown in Table 3. Except as described above, an acid-base-containing ink was prepared in the same manner as in Example 7, and using these conductor pattern forming ink, acid-base-containing ink, and temporary molded body, in the same manner as in Example 7 above. A ceramic green sheet (ceramic molded body) was produced.

(Comparative Example 1)
A ceramic green sheet (ceramic molded body) was produced in the same manner as in Example 1 except that a ceramic green sheet containing no acid and base was used.
Table 1 shows the blending amount of each constituent material of the conductor pattern forming ink for each of the above Examples and Comparative Examples, and the blending amount of each constituent material of the ceramic green sheet for each of the above Examples 1 to 6 and Comparative Example 1, Table 2 shows the blending amounts of the constituent materials of the temporary molded bodies for Examples 7 to 13, and Table 3 shows the blending amounts of the constituent materials of the acid-base-containing inks for Examples 7 to 13. In the table, polyglycerin is PG, maltodextrin is Mds, reduced maltodextrin is Rmd, trimethylolpropane is TMP, acetic acid is AcA, propionic acid is PrA, polyethyleneimine is PEI, and triethanolamine is TEA. In addition, the viscosity of the conductor pattern forming ink for each of the examples (viscosity at 25 ° C. measured according to JIS Z8809 using a vibration viscometer) is 5.0 mPa · s or more and 10 The value was within a range of 0.0 mPa · s or less. Further, the viscosity of the acid-base-containing inks in Examples 7 to 13 (viscosity at 25 ° C. measured according to JIS Z8809 using a vibration viscometer) is 5.0 mPa · s or more. The value was within a range of 10.0 mPa · s or less. Further, the column of “pH” in Table 3 shows the value of the hydrogen ion index (pH) of the acid-base-containing ink.

[3] Manufacture of ceramic circuit boards (for inner layer evaluation)
For each of the examples and comparative examples, a ceramic circuit board was produced as follows using the conductive pattern forming ink and the ceramic green sheet (ceramic molded body) obtained as described above.
First, the conductor pattern forming ink was put into an ink jet apparatus as shown in FIGS.

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 (precursors) 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 heated and dried at 60 degreeC for 30 minutes.
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 first ceramic green sheet is laminated under the second ceramic green sheet, and two non-processed ceramic green sheets are laminated as a reinforcing layer. Next, at a temperature of 95 ° C., 260 kg / cm ^The raw laminate was obtained by pressing at a pressure of ² for 30 minutes. Twenty such raw laminates were produced for each of the examples and comparative examples.
Next, in the atmosphere, the temperature is increased continuously at a temperature rising rate of 66 ° C./hour for about 6 hours, a temperature rising rate of 10 ° C./hour for about 5 hours, and a temperature rising rate of 85 ° C./hour for about 4 hours. The ceramic circuit board was obtained through a temperature process and sintering according to a sintering profile of holding at a maximum temperature of 890 ° C. for 30 minutes.

[4] Manufacture of ceramic circuit boards (for surface layer evaluation)
In addition to the ceramic circuit board for inner layer evaluation (see [3] above), using the ceramic green sheet produced in [1] above and the conductor pattern forming ink set prepared in [2] above, A ceramic circuit board was produced as follows.
First, the conductor pattern forming ink was put into an ink jet apparatus as shown in FIGS.

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 (precursors) having a line width of 30 μm, a thickness of 17 μm, and a length of 10.0 cm were drawn. The distance between each line was 5 mm. A 1.5 mm square pattern was formed at both ends of each line to form terminal portions. And the ceramic green sheet in which this line was formed was put into the drying furnace, and it heated and dried at 60 degreeC for 30 minutes.
The ceramic green sheet on which the line was formed as described above was used as the first ceramic green sheet.

Next, four unprocessed ceramic green sheets as a reinforcing layer were laminated under the first ceramic green sheet, and then pressed at a temperature of 95 ° C. and a pressure of 260 kg / cm ² for 30 minutes, A laminate was obtained. Twenty such raw laminates were produced for each of the examples and comparative examples.
Next, in the atmosphere, the temperature is increased continuously at a temperature rising rate of 66 ° C./hour for about 6 hours, a temperature rising rate of 10 ° C./hour for about 5 hours, and a temperature rising rate of 85 ° C./hour for about 4 hours. The ceramic circuit board was obtained through a temperature process and sintering according to a sintering profile of holding at a maximum temperature of 890 ° C. for 30 minutes.

[5] Evaluation of ceramic circuit board (conductivity reliability)
For the ceramic circuit boards for inner layer evaluation and surface layer evaluation obtained in each of the above examples and comparative examples, a tester was applied between the terminal portions formed on the 20 conductor patterns to confirm the presence or absence of conduction, Those in which conduction was confirmed for all 20 conductor patterns were regarded as non-defective products, 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.

[6] Adhesiveness of Conductor Pattern to Ceramic Substrate For each Example and Comparative Example, a conductor pattern formed using the conductor pattern forming ink and ceramic green sheet (ceramic molded body) obtained as described above. The adhesion to the ceramic substrate was evaluated as follows.
Using conductive pattern forming ink, 200 lines (conductor pattern precursor) having a line width of 25 μm, a thickness of 20 μm, and a length of 10.0 cm are sequentially formed on a ceramic green sheet with a spacing of 0 on a ceramic green sheet. Drawing and forming a film.
Thereafter, the ceramic green sheet on which the film was formed was degreased and sintered under the same conditions as above to obtain a ceramic substrate having a film (corresponding to a conductor pattern).
In accordance with JIS K5600, the cross-cut method was used to evaluate the adhesion between the film and the substrate according to the following four criteria.

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 4.

  As apparent from Table 4, 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) 13 ... Acid base containing part 14 ... Temporary molded object 15 ... Ceramics green sheet (ceramics molded object) 16 ... Conductor post (contact precursor) 17 ... Laminate 20 ... Conductor pattern (circuit) 30 ... Ceramic circuit board (wiring board) 31 ... Ceramics board 32 ... Laminated 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 ... Main body 115 ... Nozzle plate 115P ... Ink ejection surface 116 ... Reservoir 117 ... Ink chamber 118 ... Nozzle (protruding part) 130 ... Base 140 ... Table 170 ... Table positioning means 171 ... First moving means 172 ... Mo Motor 180 ... head positioning means 181 ... second moving means 182 ... linear motors 183, 184, 185 ... motor 190 ... control device 191 ... driving circuit 200 ... conductor pattern forming ink (ink) S ... substrate

Claims (11)

A ceramic molded body preparation step comprising a sheet-shaped ceramic molded body comprising a ceramic material and a binder and comprising at least a part of the surface and containing an acid or a base;
A conductor pattern precursor forming step of forming a conductor pattern precursor by discharging a conductive pattern forming ink containing metal particles and an organic component to a region containing the acid or base of the ceramic molded body by a droplet discharge method; ,
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 ceramic molded body is obtained by applying a composition containing an acid or a base to a temporary molded body obtained by molding a composition containing the ceramic material and the binder. A manufacturing method of the wiring board according to 1.   The method for manufacturing a wiring board according to claim 2, wherein the composition containing an acid or a base is selectively applied to a region to which the conductive pattern forming ink is applied.   4. The method for manufacturing a wiring board according to claim 2, wherein the application of the composition containing an acid or a base is performed by a droplet discharge method.   The method for manufacturing a wiring board according to claim 1, wherein the ceramic molded body is obtained by molding a composition containing an acid or a base in addition to the ceramic material and the binder.   6. The conductive pattern forming ink further comprises a water-soluble polysaccharide having a weight average molecular weight of 1,000 or more and 5,000 or less and a polyglycerol compound having a polyglycerol skeleton. A method for manufacturing a wiring board according to claim 1.   The method for manufacturing a wiring board according to claim 6, wherein the conductive pattern forming ink contains maltodextrin that is solid at room temperature as the polysaccharide.   The method for manufacturing a wiring board according to claim 6 or 7, wherein the conductive pattern forming ink contains a polysaccharide in which a carbonyl group is reduced as the polysaccharide.   The method for manufacturing a wiring board according to claim 1, wherein the ceramic molded body contains polyvinyl butyral as the binder. 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 an organic component;
An ink set for forming a conductor pattern comprising an acid or an acid-base-containing ink containing a base.   A wiring board manufactured using the method according to claim 1.

Images