JPH10330167A - Ceramic green sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a ceramic green sheet having both fixed air permeability and flexibility. SOLUTION: This ceramic green sheet comprises ceramic powder and an organic composition and has pores having an average pore diameter in the range of 100 nm to 1 μm. A ceramic green sheet comprises ceramic powder and an organic composition and has the total volume of pores contained in the green sheet in the range of 0.02 cc/g to 0.2 cc/g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic green sheet suitably used for forming a fired ceramic substrate and the like, and a method for laminating the green sheets. The present invention relates to a fired ceramic substrate preferably used for high-density mounting and the like, particularly a green sheet made of ceramics suitably used for a multilayer ceramic substrate, and a method of laminating the green sheets.

[0002]

2. Description of the Related Art In recent years, as electronic components have been operated at higher speeds, higher frequencies, and smaller sizes, it has been required to form fine via holes at a high density in ceramic substrates for mounting them.

As described in JP-A-1-231797 and JP-A-2-141458, conventional ceramic green sheets are usually prepared by appropriately adding ceramic powder, an organic binder, a plasticizer, a solvent and, if necessary, a dispersant. After blending and mixing to obtain a slurry, the obtained slurry is formed into a green sheet by a known method such as a doctor blade method.

Further, a via hole is formed in the green sheet, and the via is filled with a conductor. Then, a pattern is formed on the surface of the sheet using a conductor paste. An adhesive is applied to the sheet surface which has been subjected to the pattern formation as described above, and several layers are laminated and thermocompression-bonded to produce a ceramic green sheet laminate.

[0005]

At the time of the above-mentioned sheet lamination, an air layer easily enters between the sheets, and the air between the sheets may escape if the flexibility of the sheet is low or if the sheet does not have air permeability. There was a problem that after trapping, the air trapped between the sheets expanded after firing and peeled off.

An object of the present invention is to provide a ceramic green sheet having both desired air permeability and flexibility.

[0007]

Means for Solving the Problems As a result of diligent research, the present inventors have found that the above object of the present invention can be achieved by providing a ceramic green sheet with pores having a specific diameter or a specific volume. The present invention has been completed.

That is, the present invention comprises a ceramic powder and an organic composition, and has an average pore diameter of 100 n.
Provided is a ceramic green sheet having pores ranging from m to 1 μm. Further, the present invention comprises a ceramic powder and an organic composition, and the total volume of the pores contained in the green sheet is from 0.02 cc / g to 0.1 g / g.
A ceramic green sheet having a range of 2 cc / g is provided. Further, the present invention comprises a ceramic powder and an organic composition, and has an average pore diameter of 100 nm to 1 μm.
m, and the total volume of the pores contained in the green sheet is 0.02 cc / g to 0.2 c.
A ceramic green sheet having a c / g range is provided.

In the present invention, it is important to impart flexibility and air permeability to the green sheet itself made of ceramics, whereby the sheets can be efficiently laminated.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The ceramic powder used in the present invention includes ceramic powder alone and glass powder.
Examples include ceramic composites, crystallized glass, and amorphous glass.

Examples of using ceramic powder alone include alumina (Al ₂ O ₃ ), zirconia (ZrO
_2), magnesia (MgO), beryllia (BeO), mullite _{(3 Al 2 O 3 · 2} SiO 2), cordierite _{(5 SiO 2 · 2 Al 2} O 3 · 2 MgO), spinel (MgO · Al ₂ O ₃ ) Forsterite (2MgO
.SiO ₂ ), anorthite (CaO.Al ₂ O ₃ .2)
SiO ₂ ), Celsian (BaO.Al ₂ O ₃ .2Si)
Powders such as O ₂ ), silica (SiO ₂ ), clinoenstatite (MgO.SiO ₂ ), and aluminum nitride (AlN), or low-temperature fired ceramic powders.

Examples of the glass-ceramics powder composite system include, for example, SiO ₂ , Al ₂ O ₃ , CaO, B ₂ O ₃
And a glass composition powder containing MgO and TiO ₂ as necessary, and alumina, zirconia, magnesia,
A raw material mixture with at least one inorganic filler powder selected from the group consisting of beryllia, mullite, cordierite, spinel, forsterite, anorthite, Celsian, silica and aluminum nitride can be used. In SiO ₂ 30 to 70 wt% Al ₂ O ₃ 5 to 25 wt% CaO 5 to 25 wt% B ₂ O ₃ 3 to 50% by weight of the composition range and more preferably ceramic powder in terms of oxide notation total amount 95 At least one selected from the group consisting of alumina, zirconia, magnesia, beryllia, mullite, cordierite, spinel, forsterite, anorthite, cellian, silica and aluminum nitride. And a raw material mixture with 60 to 40% by weight of the inorganic filler powder. That is, SiO ₂ , Al ₂ O ₃ , CaO, B ₂
The composition range of O ₃ , MgO and TiO ₂ is the ratio in the glass composition powder, and it is preferable that these components have a total amount of 95% by weight or more in the glass composition powder. The remaining 5% by weight is Na ₂ O, K ₂ O, BaO, PbO, Fe ₂ O
₃ , Mn oxide, Cr oxide, NiO, Co oxide and the like.

Specific examples of the glass-ceramic composite system include SiO ₂ —B ₂ O ₃ system glass, PbO—SiO ₂
-Al ₂ O ₃ -B ₂ O ₃ based glass, CaO-SiO ₂ -
Examples thereof include those obtained by adding ceramic components such as Al ₂ O ₃ , quartz (SiO ₂ ), ZrO ₂ , and cordierite to an Al ₂ O ₃ —B ₂ O ₃ system glass or the like.

The SiO ₂ in the glass composition powder is 30 to 70
It is preferably in the range of 30% by weight. If the amount is less than 30% by weight, the strength and stability of the glass layer are reduced, and the dielectric constant and the coefficient of thermal expansion are increased, so that the glass layer tends to deviate from desired values. 7
If it exceeds 0% by weight, the coefficient of thermal expansion of the fired substrate becomes high, and it becomes difficult to fire at 1000 ° C. or less.

Al ₂ O ₃ is preferably blended in a range of 5 to 25% by weight. If it is less than 5% by weight, the strength in the glass phase is reduced, and baking at 1000 ° C. or lower becomes difficult. If it exceeds 25% by weight, the temperature at which the glass composition is fritted becomes too high.

[0016] CaO is preferably blended in the range of 5 to 25% by weight. If the amount is less than 5% by weight, a desired coefficient of thermal expansion cannot be obtained, and baking at 1000 ° C. or lower becomes difficult. If it exceeds 25% by weight, the dielectric constant and the coefficient of thermal expansion increase, which is not preferable.

B ₂ O ₃ has a glass frit of 1300-1.
For melting at a temperature around 450 ° C., and for Al ₂ O ₃
In order to control the ceramic firing temperature in the range of 800 to 1000 ° C so that the electrical, mechanical and thermal properties such as dielectric constant, strength, coefficient of thermal expansion, sintering density, etc. are not impaired even when the amount is large. And the amount is preferably in the range of 3 to 50% by weight. If the content is less than 3% by weight, the strength of the ceramic tends to decrease if the content of B ₂ O ₃ is too large, and if the content exceeds 50% by weight, the stabilization of the glass is reduced, and the glass is regenerated by the reaction between the inorganic filler (crystal) and the glass. Crystallization is accelerated, and when a multi-layer substrate is formed, a phenomenon in which a glass phase oozes out is not preferable.

The inorganic filler powder is effective for improving the mechanical strength of the substrate and controlling the coefficient of thermal expansion. In particular, alumina, zirconia, mullite, cordierite, and anorthite have excellent effects. If the proportion of the inorganic filler exceeds 60% by weight, sintering becomes difficult, and sintering at 1000 ° C. or lower becomes difficult. If it is less than 40% by weight, it becomes difficult to control the thermal expansion coefficient and obtain a substrate having a low dielectric constant. Therefore, by setting the inorganic filler powder in this range, the firing temperature of the ceramic is set to 800 to 1000 ° C., and the strength, the dielectric constant, the thermal expansion coefficient, the sintered density, and the volume resistivity shrinkage can be set to desired characteristics. .

In the present invention, MgO may be blended in the range of 0 to 10% by weight to control the glass melting temperature. If it exceeds 10% by weight, the obtained substrate has a high coefficient of thermal expansion.

In the present invention, TiO ₂ is contained in an amount of 0 to 15% by weight as a nucleating substance effective in producing crystallized glass.
You may mix | blend in the range of. Before firing, the low-temperature fired ceramic substrate of the present invention is a mixture of amorphous glass and an inorganic filler, but depending on the type of filler, becomes a partially crystallized ceramic of amorphous glass, ceramic, and crystallized glass. It is estimated that there is.

In the inorganic filler powder used in the present invention,
Na ₂ O, K ₂ O, B up to 0 to 5% by weight as impurities
aO, PbO, Fe ₂ O ₃ , Mn oxide, Cr oxide,
NiO, Co oxide and the like can be contained.

As a method of producing the glass composition powder, for example, raw materials such as SiO ₂ , Al ₂ O ₃ , CaO, and B ₂ O ₃
, MgO, after melting and TiO _2, and quenched, there is a method by grinding after the glass frit and fine powder of 0.5 to 3 [mu] m. As a raw material, a high-purity carbonate, oxide, hydroxide or the like can be used. In addition, depending on the type and composition of the glass powder, an ultra-high purity alkoxide or organometallic raw material of 99.99% or more is used. This is preferable because a high-strength ceramic substrate can be obtained.

As a specific example of the crystallized glass, MgO—
Al ₂ O ₃ —SiO ₂ or Li ₂ O—Al ₂ O ₃ —Si
O ₂ -based crystallized glass or the like is used. Crystallized glass is obtained by adding B ₂ O ₃ and a nucleating substance to MgO—Al ₂ O ₃ —SiO ₂ , firing at 900 to 1000 ° C., and precipitating cordierite crystals to increase strength, L
_{i 2 O-Al 2 O 3} -SiO 2 in B ₂ O ₃ and nucleating agent was added, to precipitate a spodumene, it is also used similarly those aimed at strengthening.

The particle size and specific surface area of the ceramic powder used in the above are selected in consideration of the thickness of the green sheet to be produced and the shrinkage ratio after firing, and the average particle size is 50% by volume particle size (D50). ) Is 1 to 6 μm,
Maximum particle size of 30 μm or less, specific surface area of 1.5 to 4
It is preferably m ² / g. More preferably, 10 volume% particle diameter (D10) 0.4 to 2 μm, 50 volume% particle diameter (D50) 1.5 to 5 μm, 90 volume% particle diameter (D9)
0): 4 to 15 μm, maximum particle size of 25 μm or less, specific surface area of 1.5 to 3.5 m ² / g, more preferably D50 of 2 to 3.5 μm, specific surface area of 1.5 to 3
m ² / g.

Here, D10, D50 and D90 are respectively 10 vol%, 5 vol.
The particle diameters of the ceramic powder are 0% by volume and 90% by volume.

By using the ceramic powder having the above-mentioned particle size distribution, the filling property of the powder is improved, and the entrapment of air bubbles is reduced even when the powder ratio in the green sheet is increased. When the particle size of the ceramic powder is smaller than the above range, the specific surface area increases, so that the cohesiveness of the powder increases and the dispersibility in the organic component decreases, so that bubbles are easily entrained. Therefore, the pores vary. Even when the particle size of the ceramic powder is larger than the above range, the bulk density of the powder is reduced, so that the filling property is reduced and the pores are likely to be large. Further, when the particle size distribution of the ceramic powder is within the above range, the powder filling ratio is high, so that the firing shrinkage ratio is low, and the via pattern shape is not easily collapsed during firing. If the ratio is out of the above range, the shrinkage after firing becomes large, and a green sheet with high accuracy cannot be obtained. The shape of the powder is preferably spherical, and a sharp particle size distribution is preferable because the influence of scattering at the time of exposure to ultraviolet light can be suppressed low.

The method for measuring the particle diameter is not particularly limited, but it is preferable to use a laser diffraction / scattering method since the measurement can be performed easily. For example, the measurement conditions when the particle size distribution analyzer HRA9320-X100 manufactured by Microtrac Co., Ltd. is used are as follows. Sample amount: 1 g Dispersion conditions: Ultrasonic dispersion in purified water for 1 to 1.5 minutes. If dispersion is difficult, perform in a 0.2% aqueous sodium hexametaphosphate solution. Particle refractive index: changed depending on the type of ceramic powder Solvent refractive index: 1.33 Number of measurements: twice

The ceramic green sheet of the present invention contains an organic composition. Examples of the organic composition include a photosensitive resin composition. When the ceramic green sheet contains a photosensitive resin composition, patterning can be performed by photolithography.

As the photosensitive resin composition, conventionally known photosensitive resins can be used. The photosensitive layer made of such a photosensitive resin is a layer that is insolubilized or solubilized by irradiating an active light beam. Examples of the photo-insolubilized photosensitive substance include (1) a mixture of a functional monomer or oligomer having one or more unsaturated groups or the like in one molecule with an appropriate polymer binder, (2) an aromatic diazo compound,
Aromatic diad compounds, those obtained by mixing a photosensitive compound such as an organic halogen compound with a suitable polymer binder,
(3) A photosensitive polymer obtained by pending a photosensitive group to an existing polymer or a modified product thereof; (4) A so-called diazo resin such as a condensate of a diazo-based amine and formaldehyde , And the like.

Examples of the photo-soluble photosensitive material include:
(1) A complex of an inorganic salt or an organic acid of a diazo compound, a quinonediazo compound mixed with an appropriate polymer binder, and (2) a quinonediazo compound combined with an appropriate polymer binder, for example, naphthoquinone of phenol or novolak resin 1,2-diazide-sulfonic acid ester, and the like.

A particularly preferred photosensitive resin composition is an acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in a side chain, and is formed by copolymerizing an unsaturated carboxylic acid and an ethylenically unsaturated group. The acrylic copolymer can be produced by adding an ethylenically unsaturated group to a side difference.

Specific examples of the unsaturated carboxylic acid include:
Acrylic acid, methacrylic acid, itaconic acid, crotonic acid,
Maleic acid, fumaric acid, vinyl acetic acid, acid anhydrides thereof, and the like. On the other hand, specific examples of the ethylenically unsaturated compound include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, n-butyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, iso-butyl acrylate, isobutyl methacrylate, tert-butyl acrylate, te
Examples include, but are not limited to, rt-butyl methacrylate, n-pentyl acrylate, n-pentyl methacrylate, styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene. By including at least methyl methacrylate among the above ethylenically unsaturated compounds as the main polymerization component of these acrylic main chain polymers, a copolymer having good thermal decomposability can be obtained.

The ethylenically unsaturated group in the side chain includes a vinyl group, an allyl group, an acryl group and a methacryl group. As a method of adding such a side chain to an acrylic copolymer, there is a method of adding an ethylenically unsaturated compound having a glycidyl group to a carboxyl group in an acrylic copolymer or an acrylic acid chloride to carry out an addition reaction. .

Examples of the ethylenically unsaturated compound having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, glycidyl ethyl acrylate, crotonyl glycidyl ether, glycidyl crotonate ether, and glycidyl ether isocrotonic acid. . In addition, examples of the acrylic chloride compound include acrylic chloride, methacrylic chloride, and allyl chloride. The addition amount of these ethylenically unsaturated compounds or acrylic acid chloride is preferably from 0.05 to 1 mol equivalent, more preferably from 0.1 to 0.8 mol, per carboxyl group in the acrylic copolymer. Is equivalent. If the added amount is less than 0.05 molar equivalent, the photosensitive characteristics become poor, and it becomes difficult to form a pattern. On the other hand, when the added amount is larger than 1 molar equivalent, the development solubility of the unexposed portion is lowered and the hardness of the coating film is undesirably lowered.

These photosensitive resins function as a polymer binder, but may contain a non-photosensitive polymer as a polymer binder component. Specific examples include polyvinyl alcohol, polyvinyl butyral, methacrylate polymer, acrylate polymer, acrylate-methacrylate copolymer, α-methylstyrene polymer, and butyl methacrylate resin.

Specific examples of the photopolymerization initiator used in the present invention include benzophenone, methyl o-benzoylbenzoate, 4,4-bis (dimethylamine) benzophenone, 4,4-bis (diethylamino) benzophenone,
4,4-dichlorobenzophenone, 4-benzoyl-4
-Methylphenylketone, dibenzylketone, fluorenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenyl-2-phenylacetone, 2-
Hydroxy-2-methylpropiophenone, pt-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-
Isopropylthioxanthone, diethylthioxanthone, benzyl, benzyldimethylketanol, benzyl-methoxyethylacetal, benzoin, benzoinmethylether, benzoinbutylether, anthraquinone, 2-t-butylanthraquinone, 2-amylanthraquinone, β-chloroanthraquinone, anthrone, benz Anthrone, dibenzazosuberone, methyleneanthrone, 4-azidobenzalacetophenone, 2,
6-bis (p-azidobenzylidene) cyclohexanone, 2,6-bis (p-azidobenzylidene) -4-methylcyclohexanone, 2-phenyl-1,2-dibutadione-2- (o-methoxycarbonyl) oxime,
-Phenyl-propanedione-2- (o-ethoxycarbonyl) oxime, 1,3-diphenyl-propanetrione-2- (o-ethoxycarbonyl) oxime, 1-
Phenyl-3-ethoxy-propanetrione-2- (o
-Benzoyl) oxime, Michler's ketone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone, naphthalenesulfonyl chloride,
Quinoline sulfonyl chloride, N-phenylthioacridone, 4,4-azobisisobutyronitrile, diphenyl disulfide, benzothiazole disulfide, triphenylphosphine, camphorquinone, carbon tetrabromide, tribromophenyl sulfone, benzoin peroxide,
Examples include a combination of a photoreducing dye such as eosin and methylene blue and a reducing agent such as ascorbic acid and triethanolamine. In the present invention, one or more of these can be used.

The photopolymerization initiator is added in an amount of 0.5 to 50% by weight based on the sum of the acrylic copolymer having a carbonyl group and an ethylenically unsaturated group in the side chain and the photoreactive compound. More preferably, it is 2 to 25% by weight. If the amount of the photopolymerization initiator is too small, the photosensitivity becomes poor, and if the amount of the photopolymerization initiator is too large, the residual ratio of the exposed portion may be too small.

In the present invention, it is preferable to add an ultraviolet (UV) light absorber to the photosensitive resin and the ceramic powder for forming a via hole in the green sheet. High resolution can be obtained by adding a light absorbing agent having a high ultraviolet absorbing effect. That is, usually, the ceramic powder alone hardens light to an unnecessary part, and it becomes impossible to form a via hole even if developed, or the roundness is greatly reduced. This is because the scattered ultraviolet light is absorbed or weakened and reaches the light-shielded portion by the exposure mask. Therefore, the addition of the ultraviolet light absorber substantially prevents the scattered light from wrapping around, prevents the photosensitive resin from being hardened in the mask portion, and forms a pattern corresponding to an exposure mask.

As an ultraviolet absorber, 350 to 450 nm
Inorganic powders or organic pigments having a high UV absorption coefficient in the above wavelength range are preferably used. As the inorganic powder, cobalt oxide Co ₂ O ₃ , CoO, iron oxide Fe ₂ O
₃ , oxides such as chromium oxide Cr ₂ O ₃ , manganese oxide MnO ₂ , copper oxide Cu ₂ O, CuO, titanium oxide TiO ₂ , titanium carbide TiC, tungsten carbide WC, zirconium carbide ZrC, silicon carbide SiC, niobium carbide NbC Such as carbide, titanium boride TiB ₂ , zirconium boride ZrB _2, etc., titanium nitride Ti
N, nitrides such as zircon nitride ZrN and tantalum nitride TaN, and carbon (C). Of these, preferred inorganic powders are carbon and carbide, which can form a sharp pattern without bleeding, and can form a via hole finely without a difference in upper and lower diameters. In particular, when carbon is fired in an oxygen-containing atmosphere, carbon is volatilized as a carbonized gas, so that deterioration of insulation and dielectric properties as a ceramic substrate can be minimized, which is preferable.

These inorganic powders can be used as a composite powder of two or more of oxides, nitrides and carbides, but are selected within a range that does not degrade the insulating and dielectric properties of the ceramic substrate. Is preferred.
The addition amount of the inorganic powder is preferably 0.01 to 5% by weight. If the amount is less than 0.01% by weight, the effect of adding the ultraviolet absorbent is reduced, and if it exceeds 5% by weight, the substrate characteristics are undesirably deteriorated. More preferably, it is 0.05 to 1% by weight.

As the organic pigment, various pigments having a high absorption coefficient can be preferably used. Specifically, azo dyes, quinoline dyes, aminoketone dyes, anthraquinone dyes and the like can be used. The addition amount is 0.01 to 5 for the same reason as in the case of the inorganic powder.
A range of weight% is preferred. Since the organic pigment does not remain in the ceramic substrate after firing like carbon, the deterioration of the substrate characteristics due to the light absorbing agent can be reduced. More preferably, 0.
It is 0.5 to 2% by weight.

In the present invention, Pb, Bi, Fe, Ni, M contained in the ceramic powder or the ultraviolet absorber are contained.
In some cases, metals such as n, Co, and Mg and oxides thereof react with carboxyl groups of the photosensitive polymer contained in the paste, causing the paste to gel in a short time and become a lump and cannot be printed as a paste. This is presumed to be an ionic cross-linking reaction between the photosensitive polymer and the above-mentioned metal or oxide powder. In order to prevent such a cross-linking reaction, not only the photosensitive polymer but also a photopolymerization initiator or a plasticizer is used. It is preferable to add a compound (stabilizer) that does not adversely affect the gelation to prevent gelation. That is, it is preferable to stabilize the ceramic green sheet by subjecting the powder to a surface treatment with a compound having an effect of forming a complex with a metal or oxide powder causing a gelling reaction or forming a salt with an acid functional group.

As a stabilizer satisfying the above requirements, a triazole compound can be preferably used. Among the triazole compounds, benzotriazole works particularly effectively. Hexamethylenetetraamine, lithium naphthenate (Li), and the like are also effective in suppressing gelation.

The method of surface-treating a metal powder and a metal oxide powder in a ceramic powder or an ultraviolet absorber using benzotriazole is as follows. That is, a predetermined amount of benzotriazole is dissolved in an organic solvent such as methyl acetate, ethyl acetate, ethyl alcohol, and methyl alcohol, and immersed in a solution for 1 to 24 hours so that these powders can be sufficiently immersed. Is preferred. After immersion, the powder is preferably air-dried, preferably at 20 to 30 ° C., and the solvent is evaporated to obtain a powder which has been subjected to a triazole treatment.

The ratio of the stabilizer used in the present invention (stabilizer / metal and metal oxide in ceramic powder or ultraviolet absorber) is preferably 0.2% to 4% by weight.
Further, the content is preferably 0.4 to 3% by weight. 0.2
When the amount is less than the weight%, there is no effect in preventing the crosslinking reaction of the polymer, and the polymer is easily gelled in a short time. On the other hand, if the content exceeds 4% by weight, the amount of the stabilizer becomes too large, and it becomes difficult to remove the binder such as the polymer binder and the stabilizer during firing of the green sheet in a non-oxidizing atmosphere, and the characteristics of the substrate deteriorate. .

In the present invention, it is also preferable to add a photoreactive compound, a sensitizer, a thermal polymerization inhibitor, a plasticizer, an antioxidant, a dispersant, an organic or inorganic precipitation inhibitor to the ceramic green sheet. Done.

A photoreactive compound is added to improve sensitivity. The photoreactive compound used in the present invention may be a compound having a photoreactive carbon-carbon unsaturated bond, and specific examples thereof include allyl acrylate, benzyl acrylate, butoxy acrylate,
Butoxyethyl acrylate, butoxytriethylene glycol acrylate, cyclohexyl acrylate,
Dicyclopentenyl acrylate, dicyclopentenyl acrylate, 2-ethylhexyl acrylate, glycidyl acrylate, heptadecafluorodecyl acrylate, 2-hydroxyethyl acrylate, isobornyl acrylate, 2-hydroxypropyl acrylate,
Isodecyl acrylate, isooctyl acrylate,
Lauryl acrylate, 2-methoxyethyl acrylate, methoxyethylene glycol acrylate, methoxydiethylene glycol acrylate, octafluoropentyl acrylate, phenoxyethyl acrylate,
Stearyl acrylate, trifluoroethyl acrylate, allyl cyclohexyl diacrylate, bisphenol A diacrylate, 1,4-butanediol acrylate, 1,3-butylene glycol diacrylate,
Ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, ditrimethylolpropane tetraacrylate, glycerol diacrylate, methoxycyclohexyl diacrylate, neo Pentyl glycol diacrylate, propylene glycol diacrylate, polypropylene glycol diacrylate, triglycerol diacrylate,
Trimethylolpropane triacrylate and the above acrylate converted to methacrylate, γ-methacryloxypropyltrimethoxysilane, 1-vinyl-
In the present invention, one or more of these photoreactive compounds can be used.

The acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in the side chain is usually used in an amount of 0.1 to 10 times by weight based on the weight of the photoreactive compound. If the amount of the acrylic copolymer is too small, the viscosity of the slurry becomes low, and the uniformity of dispersion in the slurry may be reduced. On the other hand, if the amount of the acrylic copolymer is too large, the solubility of the developer in the unexposed portions becomes poor.

A sensitizer is added to improve high sensitivity. Specific examples of the sensitizer include 2,3-bis (4-
Diethylaminobenzal) cyclopentanone), 2,6
-Bis (dimethylaminobenzal) cyclohexanone,
2,6-bis (4-dimethylaminobenzal) -4-methylcyclohexanone, Michler's ketone, 4,4-bis (diethylamino) -benzophenone, 4,4-bis (dimethylamino) chalcone, 4,4-bis (diethylamino) ) Chalcone, p-dimethylaminocinnamylidene indanone, p-dimethylaminobenzylidene indanone, 2- (p-dimethylaminophenylenevinylene)-
Isonaphthol, 1,3-bis (4-dimethylaminobenzal) acetone, 1,3-carbonyl-bis (4-diethylaminobenzal) acetone, 3,3-carbonyl-bis (7-diethylaminocoumarin), N- Phenyl-N-ethylethanolamine, N-phenylethanolamine, N-tolyldiethanolamine, N-phenylethanolamine, isoamyl dimethylaminobenzoate, isoamyl diethylaminobenzoate, 3-phenyl-5-benzoylthio-tetrazole, 1-phenyl −
5-ethoxycarbonylthio-tetrazole and the like. In the present invention, one or more of these can be used. Some sensitizers can also be used as photopolymerization initiators. When a sensitizer is added to the ceramic green sheet of the present invention, the addition amount is usually 0.1 to 60% by weight based on an acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in a side chain. More preferably, it is 0.5 to 30% by weight. If the amount of the sensitizer is small, the effect of improving the photosensitivity is not exhibited, and if the amount of the sensitizer is too large, the residual ratio of the exposed portion may be too small.

The thermal polymerization inhibitor is added to improve the thermal stability during storage. Specific examples of the thermal polymerization inhibitor include hydroquinone, N-nitrodiphenylamine,
Examples include phenothiazine, pt-butylcatechol, N-phenylnaphthylamine, 2,6-di-t-butyl-p-methylphenol, chloranil, pyrogallol, and the like. When a thermal polymerization inhibitor is added, the addition amount is usually 0.1 to 20% by weight, more preferably 0.5 to 20% by weight, based on the acrylic copolymer having an ethylenically unsaturated group in a side chain. 10% by weight. If the amount of the thermal polymerization inhibitor is small, the effect of improving the thermal stability during storage is not exhibited, and if the amount of the thermal polymerization inhibitor is too large, the residual ratio of the exposed portion may be too small. .

Specific examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, polyethylene glycol, glycerin and the like.

An antioxidant is added to prevent oxidation of the acrylic copolymer during storage. Specific examples of the antioxidant include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-4-ethylphenol, and 2,2-methylene-bis. -(4-methyl-6-t-butylphenol), 2,2
-Methylene-bis- (4-ethyl-6-t-butylphenol), 4,4-bis- (3-methyl-6-t-butylphenol), 1,1,3-tris- (2-methyl-
6-t-butylphenol), 1,1,3-tris-
(2-methyl-4-hydroxy-t-butylphenyl)
Butane, bis [3,3-bis- (4-hydroxy-3-
[t-butylphenyl) butyric acid] glycol ester, dilaurylthiodipropionate, triphenylphosphite, and the like. When the antioxidant is added, the amount of the antioxidant is usually 0.0% with respect to the total of the ceramic powder, the acrylic copolymer having an ethylenically unsaturated group in the side chain, the glass frit and the photopolymerization initiator.
It is 1 to 5% by weight, more preferably 0.1 to 1% by weight. If the amount of the antioxidant is small, the effect of preventing oxidation of the acrylic copolymer during storage cannot be obtained, and if the amount of the antioxidant is too large, the residual ratio of the exposed portion may be too small.

The ceramic green sheet of the present invention preferably contains the above organic matter in a total amount of 5 to 25% by weight. Moreover, it is preferable to contain 1-20 weight% of a plasticizer.

When the organic composition contains a photosensitive resin, a preferable composition of the slurry for forming a ceramic green sheet of the present invention is preferably selected in the following range. (a) ceramic powder; 70 to 95% by weight (b) photosensitive resin; 25 to 10% by weight (c) UV absorber: 0 to 1% by weight (preferably 0.05 to 1% by weight)

Also, the ceramic green sheet is
Ceramic powder, UV absorber, acrylic copolymer having carboxyl group and ethylenically unsaturated group in side chain,
When a photopolymerization initiator is contained, it is preferable to select a preferred composition of the slurry for forming a ceramic green sheet in the following range. (A) ceramic powder; 70 to 95% by weight; (b) an acrylic copolymer (and a photoreactive compound) having a carboxyl group and an ethylenically unsaturated group in a side chain;
0 to 5% by weight (c) Photopolymerization initiator; 2 to 25% by weight with respect to (b) (d) UV absorber; 0.01 to with respect to (a)
5% by weight

When each component is within the above range, ultraviolet rays are well transmitted at the time of exposure, the photocuring function is sufficiently exhibited, and the occurrence of a residual film at the unexposed portion during subsequent development can be almost eliminated. Via holes having roundness can be formed. In particular, by setting the acrylic copolymer (and the total amount thereof when a photoreactive compound is used) as the component (b) within this range, the sintered body after firing becomes dense and has a high strength. There is an advantage that a ceramic substrate can be obtained.

The slurry for forming a ceramic green sheet of the present invention can be produced by dissolving a photosensitive resin in an organic solvent and dispersing a ceramic powder and an ultraviolet absorber in this solution. When the ceramic green sheet contains a ceramic powder, an ultraviolet absorber, an acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in the side chain, and a photopolymerization initiator, the carboxyl group is added to the side chain. And an acrylic copolymer having an ethylenically unsaturated group and a photoinitiator are dissolved in an organic solvent, and a ceramic powder and an ultraviolet absorber are dispersed in this solution. The organic solvent used at this time may be any as long as it can dissolve a mixture of a photosensitive resin or an acrylic copolymer having an ethylenically unsaturated group in a side chain and a photopolymerization initiator. For example, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, γ-butyrolactone, toluene, trichlorethylene, methyl isobutyl Ketone, isophorone and the like and an organic solvent mixture containing at least one of them are used. Further, when the photoreactive compound is used, the photoreactive compound can dissolve a mixture of a photosensitive resin or an acrylic copolymer having an ethylenically unsaturated group in a side chain and a photopolymerization initiator. In the case of the above, each of the above components may be dissolved in the photoreactive compound instead of the above organic solvent. In this case, the above-mentioned organic solvent can also be added for adjusting the viscosity.

The method of adding the ultraviolet light absorber is as follows. After the ceramic powder and the ultraviolet light absorber are wet-mixed in an aqueous solution,
There is a method of drying. More preferably, a method of uniformly mixing and dispersing ceramic powder in an aqueous solution of an inorganic salt so as to have a predetermined addition amount, followed by drying and firing to prepare a mixed powder. By this method, a so-called capsule-like powder in which the surface of each ceramic powder is coated with an inorganic film or a fine powder can be produced. For example, when adding iron oxide or cobalt oxide as an ultraviolet absorber, after dispersing the ceramic powder in an aqueous solution of iron chloride or cobalt chloride, the mixture is dried with stirring, and dried at 400 to 8%.
By performing heat treatment at 00 ° C., a film of iron oxide or cobalt oxide can be formed on the surface of the ceramic powder. CVD when adding carbon as UV absorber
It is more preferable to form a uniform carbon film on the surface of the ceramic powder by a (chemical vapor deposition) method or the like. Also,
When an organic pigment is added as an ultraviolet absorber, the ceramic powder is homogeneously mixed and dispersed in a solution in which the organic pigment is dissolved, and then dried to form an organic pigment film on the surface of each particle of the ceramic powder. The effect of the agent is further enhanced.

Further, if necessary, an organic solvent, a stabilizer, a sensitizer, a thermal polymerization inhibitor, a plasticizer, an antioxidant, a dispersant, an organic or inorganic precipitation inhibitor, etc. are added, and a ball mill or an atomizer is added. The mixture is ground and mixed with a lighter for, for example, 12 to 48 hours to prepare a slurry.

The above-mentioned organic solvent is added as needed to adjust the viscosity of the slurry. The preferred viscosity is 1500 to 20,000 cps (centipoise), and within this range, the thickness of the sheet can be adjusted uniformly. Using a doctor blade obtained slurry continuously on a film such as a polyester film to a thickness of 0.01 to
Formed to 0.5 mm. Then, the mixture is heated at a temperature of 80 to 120 ° C. for 10 minutes to 3 hours to evaporate the solvents to form a ceramic green sheet. This sheet is cut into a predetermined shape.

The thickness of the ceramic green sheet of the present invention is usually in the range of 5 to 500 μm, preferably 30 to 300 μm. If it exceeds 500 μm, it will not transmit sufficiently to exposure to ultraviolet light, and the effect of photocuring will be weakened.
If the thickness is less than 5 μm, it becomes difficult to handle the green sheet.

The ceramic green sheet is exposed using a usual photomask method. As the active light source used at this time, for example, ultraviolet rays, electron beams, X-rays and the like can be mentioned, and among them, ultraviolet rays are preferable, and as the light source, for example, low pressure mercury lamp, high pressure mercury lamp, halogen lamp, germicidal lamp, etc. Can be used. Among these, an ultra-high pressure mercury lamp is preferable. Exposure conditions vary depending on the thickness of the green sheet and the like, but it is preferable to perform exposure for 1 to 30 minutes using an ultra-high pressure mercury lamp having an output of 5 to 100 mW / cm ² . As a method of exposing both sides of the sheet, there is a method of simultaneously exposing from both upper and lower surfaces of the sheet, or a method of exposing one side of the sheet and then inverting the front and back of the sheet and exposing the opposite side in the same manner.

After exposure, development is carried out using a developing solution to remove portions that have not been photocured, to form a so-called negative pattern, and to form a via hole having a diameter of, for example, 0.005 to 0.2 m.
m is a via hole pitch, for example, 0.01 to 5.0 mm.
At intervals. As a developing method, an immersion method or a spray method can be used. As the developer, an organic solvent in which a mixture of the acrylic copolymer having an ethylenically unsaturated group in the side chain, a photoreactive compound, and a photopolymerization initiator can be used. In addition, water may be added to the organic solvent as long as the dissolving power is not lost. When a carboxyl group is present in the side chain of the acrylic copolymer, development can be performed with an aqueous alkali solution. As the alkali aqueous solution, a metal alkali aqueous solution such as a sodium hydroxide or calcium hydroxide aqueous solution can be used, but it is preferable to use an organic alkali aqueous solution since the alkali component can be easily removed during firing. Specific examples of the organic alkali include tetramethylammonium hydroxide, trimethylbenzylammonium hydroxide, monoethanolamine,
And diethanolamine. The concentration of the alkaline aqueous solution is usually 0.01 to 10% by weight, more preferably 0.1 to 5% by weight. If the alkali concentration is too low, the unexposed portions are not removed, and if the alkali concentration is too high, the exposed portions may be peeled off and corroded, which is not preferable. The via hole can be formed by conventional punching in addition to the photolithography method described above.

The via-formed sheet is filled with vias with various conductive pastes to form a pattern.

The sheet after the pattern formation is laminated by a thermocompression bonding method while applying an adhesive to the surface and performing positioning. The lamination conditions are usually performed in a temperature range of 80 to 150 ° C. and a pressure of 0.3 to 10 kg / cm ² .

At this time, if the air permeability of the sheet is poor, the contained air cannot escape and an air layer is formed between the sheets. This is not preferable because the conductor is not bonded between the sheets.

In order to solve this problem, the green sheet has pores having an average pore diameter in the range of 100 nm to 1 μm, or the total volume of the pores contained in the green sheet is 0.02cc / g-0.2c
It is important that the range is c / g. More preferably, the total volume of the pores ranges from 0.04 cc / g to 0.15 cc / g. It is preferable that the above conditions be satisfied at the same time. In addition, green sheets 800 ~
It is important that the pores of the green sheet remain within the above range after heat treatment at 1000 ° C. or after exposure to ultraviolet light. Furthermore, in a ceramic green sheet having a film thickness of 50 μm or more,
After the heat treatment, the average pore diameter at a depth from the surface to 10 μm is in the range of 100 nm to 1000 nm,
And the pore volume of the portion is 0.05 cc / g to 0.2 c
It is preferably c / g.

If the average pore diameter is smaller than 100 nm or the total volume of the pores is less than 0.02 cc / g, it takes time until the contained bubbles are completely removed, and the bubbles remain. I will. The average pore diameter is 1μ.
m or the total volume of the pores is 0.2
If it exceeds cc / g, the strength of the sheet becomes too low,
It cannot be put to practical use.

In order to firmly press the green sheet, it is important that the sheet has flexibility.
In order to improve the flexibility of the sheet, it is desirable that the amount of the organic composition in the sheet component, particularly the amount of the plasticizer, be large, but if it is too large, the gaps between the ceramic powders are filled and the air permeability is impaired. . For this reason, it is necessary for the lamination property of the sheet to have both flexibility and air permeability. In order to satisfy the above conditions, it is preferable that the amount of the organic composition contained in the green sheet is 5 to 25% by weight as described above. Further, the amount of the plasticizer is preferably 1 to 20% by weight. Further, the diameter and volume of the pores are also affected by the degree of solvent removal by drying or the like, the shape, particle size, and dispersion state of the ceramic powder.

Next, the green sheet is fired in a firing furnace. The firing atmosphere and temperature vary depending on the type of the green sheet, but firing is performed in air, nitrogen, hydrogen, or the like. As the firing furnace, a batch-type firing furnace or a belt-type continuous furnace can be used. The firing temperature is usually from 800 to 1600C.

[0071]

The present invention will be described below in detail with reference to examples. In the following description, the amounts used and the mixing ratios are all indicated by weight.

Examples 1-4 A. Ceramic component Alumina powder; D10: 0.4 μm, D50: 2.8 μ
m, D90: 15 μm, maximum particle size: 20 μm, specific surface area: 2.0 m ² / g spherical powder

B. UV absorber Organic pigment; Azo dye Sudan-IV

C. Polymer binder Addition reaction of glycidyl acrylate in an amount of 0.4 equivalent to 40 mol% of methacrylic acid, 30 mol% of methyl methacrylate and 30 mol% of styrene (corresponding to 40 mol% of methacrylic acid). .

D. Photoreactive compound Trimethylol, propane, triacrylate

E. Photopolymerization initiator 2-methyl-1- [4- (methylthio) phenyl] -2
Morpholinopropanone-1

F. Sensitizer I; 2,4-diethylthioxanthone Sensitizer II; ethyl p-dimethylaminoaminobenzoate

G. Solvent 9: 1 mixed solvent of methyl ethyl ketone and n-butyl alcohol

H. Plasticizer dibutyl phthalate

<Manufacture of Green Sheet> a. Treatment of ceramic powder with ultraviolet light absorber Ceramic powder, ultraviolet light absorber, and dispersant were added so as to have a predetermined composition, and the mixture was stirred for 1 hour with an evaporator to disperse the ultraviolet light absorber into the ceramic powder.
After filtering this through a 250 mesh filter,
Until the dispersant was evaporated and removed.

A. Preparation of Organic Vehicle The solvent and polymer binder were mixed and heated at 60 ° C. with stirring to dissolve all polymers. Then, the solution was cooled to room temperature, and a photopolymerization initiator, a photoreactive compound, a sensitizer, and a plasticizer were added and dissolved. Thereafter, the solution was degassed in vacuo with a stirrer, and then filtered through a 250-mesh filter to prepare an organic vehicle.

B. Preparation of Slurry To prepare a slurry, the above-mentioned vehicle was mixed with a ceramic powder treated with a light absorbing agent, and was wet-mixed with a ball mill for 20 hours to prepare a slurry. Table 1 shows the prepared compositions.

C. Preparation of Green Sheet Molding was performed by a doctor blade method at a molding speed of 0.2 m / min with a spacing between the polyester carrier film and the blade of 0.1 to 0.8 mm in a room shielded from ultraviolet rays. Table 1 shows the thickness of the obtained green sheet.

D. Measurement of Pore Size Distribution and Pore Volume of Green Sheet The green sheet produced above was cut into 50 mm squares, dried at a temperature of 80 ° C. for 1 hour, and the solvent was evaporated. Next, the sheet was subdivided and the pressure was increased to 30,000 atm with a mercury porosimeter, and the pore distribution in the range of 10 nm to 10000 nm was measured.

E. Green Sheet Firing The green sheet prepared above is cut into 50 mm squares,
The three sheets were thermocompression bonded at 120 ° C. with a compression strength of 10 kg / cm ² . Further, at 1550 ° C. in a hydrogen atmosphere,
It was baked for 0 hours. The fired sheet had no swelling due to the inclusion of air bubbles, and no peeling between the sheets occurred.

[0086]

[Table 1]

Comparative Example 1 A green sheet was produced in the same manner as in Example. Table 2 shows the sheet composition and pore measurement results in this case. Furthermore, when three sheets were thermocompressed and fired under the same conditions as in the example, small swelling occurred after thermocompression, and peeling between the sheets occurred after firing.

[0088]

[Table 2]

[0089]

As described above, the present invention has the above-mentioned structure, so that air can escape from the pores even if bubbles are trapped between the sheets during lamination of the sheets. Has the advantage that it can be easily and accurately multi-layered without expanding and peeling off.

Claims (6)

[Claims] 1. A ceramic green sheet comprising a ceramic powder and an organic composition and having pores having an average pore diameter in the range of 100 nm to 1 μm. 2. A ceramic green sheet comprising a ceramic powder and an organic composition, wherein the total volume of pores contained in the green sheet is in the range of 0.02 cc / g to 0.2 cc / g. 3. A ceramic sheet and an organic composition having pores having an average pore diameter in a range of 100 nm to 1 μm, and a total volume of pores contained in a green sheet is 0.02 cc. / G to 0.2 cc / g. 4. The green sheet according to claim 1, wherein the amount of the organic component contained in the green sheet is 5 to 25% by weight.
Ceramic green sheets according to the item. 5. The ceramic green sheet according to claim 1, comprising 1 to 20% by weight of a plasticizer. 6. The ceramic green sheet according to claim 1, wherein the organic composition is a photosensitive resin composition.