JP2005241931A - Photosensitive ceramic composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive ceramic composition capable of forming a high-definition via hole having a high aspect ratio by a photolithographic method, containing uniformly dispersed fine ceramic powder, and ensuring a good light transmittance of a sheet. <P>SOLUTION: In the photosensitive ceramic composition having an inorganic component and a photosensitive organic component as essential components, the inorganic component includes inorganic fine particles whose average particle diameter is 5-500 nm, and the photosensitive organic component includes a monomer represented by the formula (1): CH<SB>2</SB>=CR<SP>1</SP>-COO-(R<SP>2</SP>O)<SB>n</SB>-OC-R<SP>3</SP>C=CH<SB>2</SB>wherein R<SP>1</SP>and R<SP>3</SP>are each H or methyl; R<SP>2</SP>includes at least one alkylene; n is a natural number of 1-15; and when n is ≥2, a plurality of symbols R<SP>2</SP>may be the same or different. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photosensitive ceramic composition. The photosensitive ceramic composition of the present invention is used for circuit materials such as a ceramic multilayer substrate for high frequency radio.

  The spread of wireless communication technology including mobile phones is remarkable. A conventional mobile phone uses a quasi-microwave band of 800 MHz to 1.5 GHz. However, as the amount of information increases, there is a wireless technology that changes a carrier frequency from a microwave band having a higher frequency to a millimeter wave band. Proposed and realized. These high-frequency radio circuits are expected to be used as mobile communications and network devices, and are becoming increasingly important technologies especially when used in Bluetooth and ITS (Intelligent Transport System). .

  In order to realize these high-frequency circuits, the substrate material used there must also have excellent high-frequency transmission characteristics in the wavelength band used, that is, 1 to 100 GHz. In order to realize excellent high-frequency transmission characteristics, it is necessary to have low dielectric constant and low dielectric loss, high processing accuracy, and good dimensional stability, and ceramic substrates are especially promising. It was.

  However, although the conventional ceramic substrate materials are excellent in dimensional stability, the fine processing degree is low, so that sufficient characteristics cannot be obtained particularly in a high frequency region. As a method for improving such a problem of fine processing accuracy, a via hole forming method using a photolithography technique using a green sheet formed from a photosensitive ceramic composition has been proposed (see, for example, Patent Document 1 and Patent Document 2). .). However, this method has a limit in forming a high aspect ratio via hole. The reason was that ultraviolet rays during photolithographic processing were diffusely reflected and did not reach the deep part.

  Therefore, as a method for solving these problems, it has been proposed to make the average particle diameter of ceramic particles contained in the sheet smaller than the wavelength of ultraviolet rays (see, for example, Patent Document 3). By this method, the light transmittance is improved, and ultraviolet rays reach the deep part of the sheet, so that a high aspect ratio via hole can be formed.

However, due to changes in market needs, the formation of via holes with a higher aspect ratio has been required, and it has become necessary to further improve the light transmittance of the sheet. In the conventional method, when the inorganic fine particles are not sufficiently dispersed, a part of the particles is aggregated, and there are particles larger than the wavelength of ultraviolet rays. This causes the transmittance of the sheet to decrease. In order to obtain a sheet with higher light transmittance, it was necessary to improve the dispersion of inorganic fine particles.
JP-A-6-202323 JP 2003-315996 A JP 2002-162735 A

  In order to enable formation of a high aspect ratio and high definition via hole using a photolithography method, it is necessary that fine ceramic powder is uniformly dispersed and the light transmittance of the sheet is good. This invention makes it a subject to provide the photosensitive ceramic composition corresponding to them.

  That is, the present invention relates to a photosensitive ceramic composition comprising an inorganic component and a photosensitive organic component as essential components, the inorganic component containing inorganic fine particles having an average particle diameter of 5 nm to 500 nm, and the photosensitive organic component represented by the general formula (1 The problem is solved by a photosensitive ceramic composition characterized by containing a monomer represented by

^{_{CH 2 = CR 1 -COO- (R}} 2 O) n -OC-R 3 C = CH 2 (1)
(Wherein R ¹ and R ³ are either hydrogen or methyl group, R ² contains at least one alkylene group. N is a natural number of 1 to 15. When n is 2 or more, each R ² Can be the same or different.)

  With the photosensitive ceramic composition of the present invention, the dispersion state of the inorganic fine particles becomes good, and a sheet with high transmittance can be obtained.

   The photosensitive ceramic composition of the present invention is a photosensitive ceramic composition comprising an inorganic component and a photosensitive organic component as essential components, the inorganic component containing inorganic fine particles having an average particle size of 5 nm to 500 nm, and the photosensitive organic component Is a photosensitive ceramic composition characterized in that it contains a monomer represented by the general formula (1).

^{_{CH 2 = CR 1 -COO- (R}} 2 O) n -OC-R 3 C = CH 2 (1)
(Wherein R ¹ and R ³ are either hydrogen or methyl group, R ² contains at least one alkylene group. N is a natural number of 1 to 15. When n is 2 or more, each R ² Can be the same or different.)
In the present invention, the photosensitive ceramic composition comprises an inorganic component and a photosensitive organic component. The inorganic component includes at least one kind of inorganic fine particles as an essential component. The average particle diameter of the inorganic fine particles is 5 to 500 nm, preferably 20 to 300 nm, and more preferably 20 to 150 nm. By using inorganic fine particles of such a size, it is possible to perform low-temperature firing, and to obtain a dense sintered body having high mechanical strength by improving the sinterability. Further, the exposure characteristics are not impaired by scattering light during exposure. When the average particle diameter exceeds 500 nm, the ultraviolet rays do not reach the deep part, so that a pattern cannot be formed. On the other hand, inorganic fine particles of less than 5 nm easily cause secondary aggregation and are difficult to handle. Examples of the inorganic fine particles include silica, alumina, titania, zirconia, yttria, and ceria. In particular, alumina is preferably used, but a plurality of components may be mixed and used. The content of the inorganic fine particles is preferably 5% by weight to 90% by weight and more preferably 20% by weight to 90% by weight with respect to the photosensitive ceramic composition. By setting the content of the inorganic fine particles to 5% by weight or more, the sheet dielectric constant characteristics after firing can be made desired, and by setting the content to 90% by weight or less, the light transmittance of the sheet is high, and photolithography Workability is improved. Moreover, the photosensitive ceramic composition of this invention may contain a metal, a metal oxide, glass, and other inorganic powder as an inorganic component. Since the glass powder transmits light such as an ultra-high pressure mercury lamp, the average particle diameter is not restricted. In addition, the inorganic component contained in the ceramic composition of the present invention is sintered in the firing step, and firing at a temperature of 1000 ° C. or less, particularly 700 to 900 ° C. is preferable in the formation of the substrate intended by the present invention. Therefore, so-called low-temperature fired inorganic powder is preferable. Of course, these inorganic components determine basic physical properties such as the electrical characteristics, strength, and thermal expansion coefficient of the substrate, and are selected according to the intended characteristics.

  The inorganic component can contain a filler component, and ceramic powder is often used as the filler component as described above, which is effective in improving the mechanical strength of the substrate and controlling the thermal expansion coefficient. In particular, alumina, zirconia, mullite, cordierite, and anorthite have excellent effects. By mixing these ceramic powders, the firing temperature can be set to 800 to 900 ° C., and the strength, dielectric constant, thermal expansion coefficient, sintered density, volume resistivity, and shrinkage rate can be set as desired characteristics.

  In order to maintain the pattern forming property at a high level in the photosensitive ceramic composition, it is important to match the refractive indexes of the inorganic component and the photosensitive organic component. The refractive index of the inorganic component can be controlled by the blending ratio of the composition, and it is preferable to consider so as to match the average refractive index of the photosensitive organic component to be blended. In some cases, a means for increasing the refractive index of the photosensitive organic component may be used, in which case it is selected from the group consisting of a sulfur atom, a bromine atom, an iodine atom, a naphthalene ring, a biphenyl ring, an anthracene ring, and a carbazole ring. For example, a method of adding 20% by weight or more of a compound having a group may be applied.

  The inorganic component of the present invention can be fired at 600 to 900 ° C., which can be multilayered using Cu, Ag, Au or the like as a wiring conductor, and approximates the thermal expansion coefficient of chip parts such as GaAs or printed circuit boards. It is preferable to provide a substrate having a thermal expansion coefficient, a low dielectric constant and a low dielectric loss even in a high frequency region.

  The photosensitive organic component contained in the photosensitive ceramic composition contains a monomer represented by the general formula (1).

^{_{CH 2 = CR 1 -COO- (R}} 2 O) n -OC-R 3 C = CH 2 (1)
(Wherein R ¹ and R ³ are either hydrogen or methyl group, R ² contains at least one alkylene group. N is a natural number of 1 to 15. When n is 2 or more, each R ² Can be the same or different.)
By adding this monomer, the inorganic fine particles are well dispersed, the light transmittance of the sheet is improved, and finer processing becomes possible. Moreover, since alkylene oxide is easily decomposable and debinders at a low temperature, firing defects are unlikely to occur.

R ² can be used by selecting one or more kinds from various alkylene groups such as ethylene group, propylene group, butylene group, etc., but it is more preferable that R ² contains an ethylene group from the viewpoint of dispersibility of inorganic fine particles. By including an ethylene group, the polarity of the molecule is increased and the affinity with the inorganic fine particles is improved, so that the dispersion of the inorganic fine particles is further improved. In the present invention, the repeating unit n is 1 to 15 from the viewpoint of handling of the monomer and inorganic fine particles, and the repeating unit n is more preferably 5 to 12. By setting n to 5 or more, skin irritation is suppressed, and by setting n to 12 or less, the viscosity of the monomer is lowered and handling becomes easier. Such compounds include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate (tetramer to 15mer), propylene glycol Di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate (tetramer to 15mer), butylene glycol di (meth) acrylate, di Examples include butylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, and polybutylene glycol di (meth) acrylate (tetramer to 15-mer).

  The monomer content represented by the general formula (1) is preferably in the range of 0.1 to 10% by weight, more preferably 2 to 10% by weight, based on the photosensitive ceramic composition. By setting the monomer content within this range, the crosslinking density after photocuring can be set within a desired range.

  The photosensitive ceramic composition of the present invention can be used in combination with monomers having various ethylenically unsaturated groups in addition to the above compounds. Examples of the monomer having an ethylenically unsaturated group include monomers having one or more photopolymerizable unsaturated groups such as a (meth) acrylate group or an allyl group. Specific examples thereof include esters of alcohols (for example, ethanol, propanol, hexanol, octanol, cyclohexanol, glycerin, trimethylolpropane, pentaerythritol, etc.) with acrylic acid (or methacrylic acid), carboxylic acids (for example, acetic acid, Propionic acid, benzoic acid, acrylic acid, methacrylic acid, succinic acid, maleic acid, phthalic acid, tartaric acid, citric acid, etc.) and glycidyl acrylate (or glycidyl methacrylate, allyl glycidyl, or tetraglycidyl metaxylylenediamine) Reaction products, amide derivatives (eg, acrylamide, methacrylamide, N-methylolacrylamide, methylenebisacrylamide, etc.), reaction products of epoxy compounds and acrylic acid (or methacrylic acid). It can be mentioned. In addition, the monomer having an ethylenically unsaturated group may be a polyfunctional monomer. In that case, the unsaturated group may be present by mixing acrylic, methacrylic, vinyl, and allyl groups. These may be used alone or in combination.

  The photosensitive ceramic composition of the present invention preferably further contains a urethane compound. By containing a urethane compound, the shrinkage stress at the time of baking can be relieved and a baking defect can be reduced.

  The molecular weight of the urethane compound used in the present invention is preferably 1500 to 50000. In addition, molecular weight here is a weight average molecular weight. By setting it as 1500 or more, the softness | flexibility of a urethane compound can be maintained and a baking defect can be reduced further. By setting it to 50000 or less, the viscosity of the urethane compound can be lowered and handling can be facilitated.

As a urethane compound used by this invention, the compound shown by following General formula (2) is mentioned, for example.
^{R 4 - (R 7 - (} R 6 O) l) m -R 7 -R 5 (2)
(R ⁴ and R ⁵ are selected from the group consisting of a substituent containing an ethylenically unsaturated group, hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group, an aralkyl group, and a hydroxyaralkyl group, and each is the same. R ⁶ is an alkylene group, R ⁷ is an organic group containing a urethane bond, l is a natural number of 1 to 200, and m is a natural number of 1 to 10.)
The urethane compound preferably contains an ethylene oxide unit. More preferably, in the general formula (2), (R ⁶ O) ₁ is an oligomer containing an ethylene oxide unit and a propylene oxide unit, and the ethylene oxide unit content in the oligomer is 8 to 70 wt. %. When the ethylene oxide unit content is 70% by weight or less, flexibility is improved and shrinkage stress at the time of firing can be reduced, so that firing defects can be effectively suppressed. Furthermore, the thermal decomposability is improved, and the firing residue is less likely to occur in the firing step after pattern formation. Moreover, compatibility with another organic component improves because ethylene oxide unit content is 8% or more.

The organic group containing a urethane bond of R ⁷ is preferably generated by condensation of a diisocyanate group and a hydroxyl group. Examples of the component having a diisocyanate group used here include aliphatic diisocyanate compounds such as 1,4-diisocyanate butane and 1,6-diisocyanate hexane, aromatic diisocyanate compounds such as 1,4-phenylene diisocyanate and toluylene diisocyanate, or 1, Examples thereof include alicyclic diisocyanate compounds such as 4-cyclohexylene diisocyanate and isophorone diisocyanate. It is more preferable to use an alicyclic isocyanate compound, and in particular, an isophorone diisocyanate is preferably used, but is not limited thereto.

  Specific examples of the urethane compound used in the present invention include “UA-2235PE” (molecular weight 18000, EO content 20%), “UA-3238PE” (molecular weight 19000, EO content 10%), “UA-3348PE”. (Molecular weight 22000, EO content 15%), “UA-2349PE” (molecular weight 27000, EO content 7%), “UA-5348PE” (molecular weight 39000, EO content 23%) (Shin Nakamura Chemical Co., Ltd. ))), But is not limited thereto. Moreover, you may use these compounds in mixture.

  The content of the urethane compound is preferably 0.1 to 10% by weight in the photosensitive ceramic composition. By setting the content to 0.1% by weight or more, a high effect can be obtained in reducing firing defects. By setting the content to 10% by weight or less, it is possible to ensure photocurability and developability of the photosensitive ceramic composition.

  The photosensitive ceramic composition of the present invention preferably contains a photosensitive and / or non-photosensitive polymer.

  The photosensitive polymer is mainly photocurable, but may be a photosoluble polymer composition. The Tg (glass transition temperature) of the polymer is preferably in the range of −60 ° C. to 30 ° C., more preferably in the range of −40 ° C. to 30 ° C. By setting Tg to −60 ° C. or higher, stickiness of the sheet after drying can be suppressed and a sheet having good process compatibility can be obtained. By making Tg 30 degrees C or less, the softness | flexibility of a sheet | seat improves and generation | occurrence | production of the cracking of a sheet | seat etc. can be suppressed. The content of such a polymer is 3% by weight to 30% by weight, preferably 3% by weight to 20% by weight, based on the photosensitive ceramic composition. Examples of the polymer herein include phenol resin, alkyd resin, petroleum resin, epoxy resin, amino resin, vinyl resin, male resin, polyester resin, acrylic resin, silicone resin, urethane resin, polyamide resin, polyimide resin, fluorine resin, Examples include rosin. Photosensitive polymers include polymers having a carboxy group in the side chain, or polymers having an ethylenically unsaturated group, and polymers having a carboxy group and an ethylenically unsaturated group in the side chain. Polymers are common. Alternatively, the dispersion characteristics of the inorganic fine particles can be optimized by blending the above various resins. The copolymerization component of the acrylic copolymer is, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, sec-butyl acrylate, iso-butyl acrylate, tert-butyl. Acrylate, n-pentyl acrylate, allyl acrylate, benzyl acrylate, butoxyethyl acrylate, butoxytriethylene glycol acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, 2-ethylhexyl acrylate, glycerol acrylate, glycidyl acrylate, heptadeca Fluorodecyl acrylate, 2-hydroxyethyl acrylate, isobo Acrylate, 2-hydroxypropyl acrylate, isodexyl acrylate, isooctyl acrylate, lauryl acrylate, 2-methoxyethyl acrylate, methoxyethylene glycol acrylate, methoxydiethylene glycol acrylate, octafluoropentyl acrylate, phenoxyethyl acrylate, stearyl acrylate, trifluoro Ethyl acrylate, allylated cyclohexyl diacrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipentaerythritol Hexaacrylate, Pentaerythritol monohydroxypentaacrylate, ditrimethylolpropane tetraacrylate, glycerol diacrylate, methoxylated cyclohexyl diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate, polypropylene glycol diacrylate, triglycerol diacrylate, trimethylolpropane triacrylate, Acrylamide, aminoethyl acrylate, phenyl acrylate, phenoxyethyl acrylate, benzyl acrylate, 1-naphthyl acrylate, 2-naphthyl acrylate, bisphenol A diacrylate, diacrylate of bisphenol A-ethylene oxide adduct, bisphenol A-propylene oxide adduct Jiacri Rate, thiophenol acrylate, benzyl mercaptan acrylate, a monomer in which 1 to 5 of these aromatic ring hydrogen atoms are substituted with chlorine or bromine atoms, or styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, chlorinated styrene, brominated styrene, α-methylstyrene, chlorinated α-methylstyrene, brominated α-methylstyrene, chloromethylstyrene, hydroxymethylstyrene, carboxymethylstyrene, vinylnaphthalene, vinylanthracene , Vinyl carbazole, and those obtained by changing some or all of the acrylates in the molecule of the above compounds to methacrylate, γ-methacryloxypropyltrimethoxysilane, 1-vinyl-2-pyrrolidone, and the like. In the present invention, one or more of these can be used.

  In addition to these, the development property after exposure can be improved by adding an unsaturated acid such as an unsaturated carboxylic acid. As specific examples of unsaturated carboxylic acids, monomers such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, or acid anhydrides thereof are selected and photoinitiators. The monomer component and the copolymerization ratio are selected so that the Tg of the acrylic copolymer obtained by polymerizing these components is in the range of −60 ° C. to 30 ° C. It is preferable to do. Moreover, it is preferable to contain the polymer which has a carboxyl group in a side chain in order to enable alkali image development, and it is preferable that the acid value of a polymer is 50-140 (mgKOH / g) for that purpose. By setting the acid value to 140 or less, the allowable development width can be widened, and by setting the acid value to 50 or more, the solubility in the alkali developer in the unexposed area is maintained, and a high-definition pattern is obtained. be able to. Further, by having an ethylenically unsaturated group in the side chain, the development allowable width is further widened, and a higher definition pattern can be obtained.

  The photosensitive ceramic composition of the present invention preferably further contains a photoinitiator. The photoinitiator is used alone or as a mixture of benzophenone, methyl o-benzoylbenzoate, 4,4-bis (dimethylamine) benzophenone, 4,4-bis (diethylamino) benzophenone, 4,4-dichlorobenzophenone 4-benzoyl-4-methyldiphenyl ketone, dibenzyl ketone, fluorenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenyl-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone Pt-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, diethylthioxanthone, benzyl, benzyldimethylketanol, benzylmethoxyethyl acetal, Zoin, benzoin methyl ether, benzoin butyl ether, anthraquinone, 2-t-butylanthraquinone, 2-amylanthraquinone, β-chloroanthraquinone, anthrone, benzanthrone, dibenzosuberone, methyleneanthrone, 4-azidobenzalacetophenone, 2,6 -Bis (p-azidobenzylidene) cyclohexanone, 2,6-bis (p-azidobenzylidene) -4-methylcyclohexanone, 2-phenyl-1,2-butadion-2- (o-methoxycarbonyl) oxime, 1-phenyl -Propanedione-2- (o-ethoxycarbonyl) oxime, 1,3-diphenyl-propanetrione-2- (o-ethoxycarbonyl) oxime, 1-phenyl-3-ethoxy-propanetrione-2- (o-ben) Zoyl) oxime, Michler's ketone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone, naphthalenesulfonyl chloride, quinolinesulfonyl chloride, N-phenylthioacridone, 4,4-azobisisobuty Photoreducing dyes such as nitrile, diphenyl disulfide, benzthiazole disulfide, triphenylformine, camphorquinone, carbon tetrabromide, tribromophenyl sulfone, benzoin peroxide and eosin, methylene blue, ascorbic acid, triethanolamine, etc. And a combination of reducing agents. The addition amount of the photoinitiator is added in the range of 0.05 to 10% by weight, more preferably 0.1 to 5% by weight, with respect to the reactive components such as the photosensitive polymer and the monomer. If the amount of the photoinitiator is too small, the photosensitivity becomes poor, and if it is too large, the residual ratio of the exposed portion may be too small.

  As other additives, it is also effective to add an ultraviolet light absorber composed of an organic dye. By adding a light-absorbing agent having a high ultraviolet absorption effect, a sheet having a high aspect ratio, high definition, and high resolution can be obtained. As the ultraviolet light absorber, an organic dye is used, and among them, an organic dye having a high UV absorption coefficient in a wavelength range of 300 to 450 nm is preferably used. Specifically, azo dyes, amino ketone dyes, xanthene dyes, quinoline dyes, amino ketone dyes, anthraquinone dyes, benzophenone dyes, diphenyl cyanoacrylate dyes, triazine dyes, p-aminobenzoic acid dyes, and the like can be used. . Even when an organic dye is added as a light-absorbing agent, it is preferable because it does not remain in the insulating film after baking and the deterioration of the insulating film characteristics due to the light-absorbing agent can be reduced. Of these, azo dyes and benzophenone dyes are preferable. The addition amount of the organic dye is preferably 0.01 to 5% by weight with respect to the photosensitive ceramic composition. When the content is 0.01% by weight or more, the effect of adding the ultraviolet light absorber is obtained, and when the content is 5% by weight or less, the influence of the residue after baking can be reduced. More preferably, it is 0.05 to 2% by weight. An example of a method for adding an ultraviolet light absorber composed of an organic dye is to prepare a solution in which an organic dye is dissolved in an organic solvent in advance, and then mix and dry the inorganic component in the organic solvent. By this method, a so-called capsule-like powder in which an organic film is coated on the surface of each powder of inorganic components can be produced.

  In the present invention, when the inorganic component contains a metal such as Pb, Fe, Cd, Mn, Co, and Mg and its oxide, the inorganic component and the organic component react with the reactive component contained in the organic component. The mixture (sheet slurry) may gel in a short time, making it impossible to form a sheet. In order to prevent such a reaction, it is preferable to add a stabilizer to prevent gelation. As a stabilizer, a triazole compound is preferably used. Among the triazole compounds, benzotriazole works particularly effectively. As an example of the surface treatment of glass powder with benzotriazole used in the present invention, a predetermined amount of benzotriazole was dissolved in an organic solvent such as methyl acetate, ethyl acetate, ethyl alcohol, and methyl alcohol with respect to the glass powder. Then, it is immersed in the solution for 1 to 24 hours so that the glass powder can be sufficiently immersed. After soaking, it is preferably air-dried at 20 to 30 ° C. to evaporate the solvent and prepare a triazole-treated powder. The proportion of the stabilizer used (stabilizer / inorganic component) is preferably 0.05 to 5% by weight.

  In the present invention, a sensitizer may be added to improve sensitivity. Specific examples of the sensitizer include 2,4-diethylthioxanthone, isopropylthioxanthone, 2,3-bis (4-diethylaminobenzal) cyclopentanone, 2,6-bis (4-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-dimethylaminophenylvinylene) -isonaphthothiazole, 1,3-bis (4-dimethylaminobenzal) Acetone, 1,3-carbonyl-bis (4-diethyla Nobenzal) 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 photoinitiators. When adding a sensitizer to the photosensitive ceramic composition of this invention, the addition amount is 0.05-5 weight% normally with respect to a reactive component, More preferably, it is 0.1-2 weight%. If the amount of the sensitizer is too 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.

  Further, a polymerization inhibitor may be added to improve the thermal stability during storage. Specific examples of the polymerization inhibitor include hydroquinone, monoester of hydroquinone, N-nitrosodiphenylamine, phenothiazine, pt-butylcatechol, N-phenylnaphthylamine, 2,6-di-tert-butyl-p- Examples include methylphenol, chloranil, and pyrogallol. When adding a polymerization inhibitor, the addition amount is 0.001 to 1 weight% normally in the photosensitive ceramic composition.

  Further, an antioxidant may be added to prevent oxidation of the acrylic copolymer during storage. Specific examples of antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-4-ethylphenol, 2,2-methylene-bis- ( 4-methyl-6-tert-butylphenol), 2,2-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4-bis- (3-methyl-6-tert-butylphenol), 1 , 1,3-Tris- (2-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4-hydroxy-tert-butylphenyl) butane, bis [3,3-bis -(4-Hydroxy-3-t-butylphenyl) butyric acid] glycol ester, dilauryl thiodipropionate, triphenyl phosphite and the like. When adding antioxidant, the addition amount is 0.001-1 weight% normally in the photosensitive ceramic composition.

  When adjusting the viscosity of the sheet slurry, a solvent may be added to the photosensitive ceramic composition of the present invention. Examples of the organic solvent used at this time include methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol, 3-methyl 3-methoxybutanol, tetrahydrofuran, dimethyl sulfone. Examples thereof include xoxide, γ-butyrolactone, bromobenzene, chlorobenzene, dibromobenzene, dichlorobenzene, bromobenzoic acid, chlorobenzoic acid, and the like, and organic solvent mixtures containing one or more of these.

The photosensitive ceramic composition of the present invention can be prepared and sheeted as follows. First, the monomer represented by the general formula (1) as a photosensitive organic component, and, if necessary, a polymer having a carboxyl group and an ethylenically unsaturated group in the side chain, a urethane compound, a photoinitiator, a solvent and various additives Are mixed and filtered to prepare an organic vehicle. To this, a pretreated inorganic component is added if necessary, and homogeneously mixed and dispersed by a kneader such as a ball mill to produce a slurry or paste of the photosensitive ceramic composition. The viscosity of the slurry or paste is appropriately adjusted depending on the mixing ratio of the inorganic component and the organic component, the amount of the solvent, and the addition ratio of other additives, but the range is preferably 1 to 5 Pa · s. The obtained paste is continuously formed to a thickness of 0.05 to 0.5 mm on a film of polyester or the like by a general method such as a doctor blade method or an extrusion molding method, and the solvent is removed by drying. A green sheet that is a functional ceramic composition is obtained. The via hole is formed by performing pattern exposure through a photomask having a via hole forming pattern on the green sheet, which is the photosensitive ceramic composition, and developing with an alkaline aqueous solution. The light source used for exposure is most preferably an ultra-high pressure mercury lamp, but is not necessarily limited thereto. Exposure conditions vary depending on the thickness of the green sheet, and exposure is performed for 5 seconds to 30 minutes using an ultrahigh pressure mercury lamp having an output of 5 to 100 mW / cm ² . In addition, the alignment guide hole at the time of sheet | seat lamination | stacking can be formed with the same method as the via hole formation. Examples of the alkaline aqueous solution include inorganic alkaline aqueous solutions such as sodium carbonate, sodium hydroxide and potassium hydroxide, and organic alkaline aqueous solutions such as tetramethylammonium hydroxide, trimethylbenzylammonium hydroxide, monoethanolamine and diethanolamine. The concentration of the alkaline aqueous solution is usually 0.05 to 5% by weight, more preferably 0.1 to 0.5% by weight. If the alkali concentration is too low, the soluble portion is not completely removed. If the alkali concentration is too high, the pattern of the exposed portion may be peeled off or eroded. The temperature during development is preferably 20 to 50 ° C. for process control. As a developing method, a general dipping method or spray method is used. There is also a method for shortening development time and reducing development unevenness by using ultrasonic waves together.

  In this manner, a sheet having a thickness before firing of 10 to 500 μm, a close-packed via hole pattern portion having a via hole diameter of 20 to 200 μm, and a via hole pitch of 30 to 250 μm can be produced. The present invention is characterized in that since the dispersion state of the inorganic fine particles is good, the light transmittance is high and the formation of a high-definition pattern is improved.

  When firing a green sheet formed from a photosensitive ceramic composition, a non-sinterable ceramic sheet may be laminated and fired on the upper and lower surfaces of the green sheet. Thereby, it is possible to shrink only in the thickness direction and almost no shrinkage in the XY plane, but the firing shrinkage rate in the XY plane direction is preferably 1% or less, more preferably 0.5. % Or less, more preferably 0.1% or less.

  The hardly sinterable ceramic is a ceramic powder that does not sinter at the substrate sintering temperature, and can be selected from amorphous silica, quartz, alumina, magnesia, hematite, barium titanate, boron nitride, and the like. Sheets obtained from these materials are referred to as dummy green sheets or restraint sheets. This sheet contains 1 to 5 oxide powders as an adhesion improver with an oxidizing agent such as lead oxide, bismuth oxide, zinc oxide, manganese oxide, barium oxide, calcium oxide, and strontium oxide, and a glass / ceramic green sheet. It is preferable to add by weight%. Examples of such hardly sinterable ceramic sheets include those formed by adding a polyvinyl butyral, dioctyl phthalate, an appropriate oxide, a solvent, etc. to an alumina powder and forming a sheet by a doctor blade method. .

  The shrinkage in the XY plane direction is limited by the firing process with the constraining sheets placed on the upper and lower surfaces of the green sheet, but there is inevitable shrinkage depending on the components of the composition, the composition of the composition, and various conditions during firing. To do. If the shrinkage rate can be suppressed to 1% or less, it can be considered that almost no shrinkage has been achieved, but more preferably 0.5% or less, and still more preferably 0.1% or less. Such a condition is also applied to a coating film formed by screen printing or the like (a method of applying a paste of a photosensitive ceramic composition to a substrate made of ceramics or the like. In the case of a coating film, since the substrate already exists on the lower surface of the film, it can be carried out with a restraint sheet disposed on the upper surface of the film. .

  Next, the sheets on which the necessary number of wiring patterns are formed are stacked using the guide holes, and bonded at a temperature of 80 to 150 ° C. and a pressure of 5 to 25 MPa, thereby producing a multilayer sheet. A constraining sheet composed mainly of an inorganic composition (eg, alumina or zirconia) that does not substantially exhibit sintering shrinkage at the sintering temperature of the green sheet is laminated on both sides of the green sheet laminate. The target multilayer board can be produced by firing the green sheet multilayer body and then performing non-shrink firing to remove the constraining sheet. Firing is performed in a firing furnace. The firing atmosphere and temperature vary depending on the types of inorganic and organic components in the photosensitive ceramic composition, but firing is performed in air, in a nitrogen atmosphere, or in a hydrogen reduction atmosphere. Firing of the photosensitive ceramic composition of the present invention is performed at a temperature of 600 to 950 ° C. The ceramic multilayer substrate thus obtained is used as a high-frequency circuit substrate.

  Hereinafter, the present invention will be specifically described with reference to examples. The concentration (%) is% by weight unless otherwise specified. The inorganic components and organic components used in the examples are as follows.

A. Inorganic component Inorganic component I:
Composite ceramic alumina of 50% alumina + 50% glass powder: average particle size 40 nm
Composition of glass powder: Al ₂ O ₃ (10.8%), SiO ₂ (51.5%), PbO (15.6%), CaO (7.1%), MgO (2.86%), Na ₂ O (3%), K ₂ O (2%), B ₂ O ₃ (5.3%)
Properties of glass powder: glass transition point 565 ° C., thermal expansion coefficient 60.5 × 10 ⁻⁷ / K, dielectric constant 8.0 (1 MHZ), average particle diameter 2 μm
Inorganic component II:
Composite ceramic silica of 50% silica + 50% glass powder: average particle size 150 nm
Composition of glass powder: Al ₂ O ₃ (10.8%), SiO ₂ (51.5%), PbO (15.6%), CaO (7.1%), MgO (2.86%), Na ₂ O (3%), K ₂ O (2%), B ₂ O ₃ (5.3%)
Properties of glass powder: glass transition point 565 ° C., thermal expansion coefficient 60.5 × 10 ⁻⁷ / K, dielectric constant 8.0 (1 MHZ), average particle diameter 2 μm
Inorganic component III: “NKX-592J” (Nippon Fellow Co., Ltd.)
Composite ceramics alumina with 50% alumina + 50% glass powder: average particle size 2.5 μm
Glass powder: Average particle size 4.8 μm
Composition of glass powder: Properties of Al ₂ O ₃ —B ₂ O ₃ —SiO ₂ —CaO-based glass glass powder: glass transition point 565 ° C., thermal expansion coefficient 60.5 × 10 ⁻⁷ / K, dielectric constant 8.0 (1MHZ), average particle size 2μm
B. Photosensitive organic component polymer: an addition reaction of 0.4 equivalent of glycidyl methacrylate to a carboxyl group of a copolymer composed of 70% 2-ethylhexyl acrylate and 30% acrylic acid, and has a weight average molecular weight of 16,000, Acid value 110 (mgKOH / g)
Monomer I: Toagosei Co., Ltd. Aronix “M-240” (CH ₂ ═CHCOO— (C ₂ H ₄ O) ₄ —COCH═CH ₂ )
Monomer II: Toagosei Co., Ltd. Aronix “M-245” (CH ₂ ═CHCOO— (C ₂ H ₄ O) ₉ —COCH═CH ₂ )
Monomer III: manufactured by Toagosei Co., Ltd. Aronix _{"M-260" (CH 2} = CHCOO- (C 2 H 4 O) 13 ~ 14 -COCH = CH 2)
Monomers IV: NOF Corporation Blenmer _{"PDP-400" (CH 2} = C (CH 3) COO- (C 3 H 6 O) 9 -COC (CH 3) = CH 2)
Monomer V: Shin Nakamura Chemical Co., Ltd. NK ester “23G” (CH ₂ ═C (CH ₃ ) COO— (C ₂ H ₄ O) ₂₃ —COC (CH ₃ ) ═CH ₂ )
Urethane compound: Shin-Nakamura Chemical Co., Ltd. NK Oligo “UA-2235PE” molecular weight 20000, EO / PO = 40% / 60%
Photoinitiator: Ciba Specialty Chemicals “IC819” (2-benzyl-dimethylamino-1- (4-monoforinophenyl) -butanone-1)
Additive: p-Methoxyphenol Solvent: Kuraray Co., Ltd. “Solfit”
C. Preparation of Organic Vehicle Solvent and polymer were mixed and heated to 60 ° C. with stirring to dissolve all the polymer. The solution was cooled to room temperature, and a monomer and a photoinitiator were added and dissolved to prepare an organic vehicle. Table 1 shows the amount of each added.

D. Paste preparation An inorganic component was mixed with the organic vehicle described above, and a slurry or paste was obtained by passing three times with a three-roll. The amount of the inorganic component was 70 parts by weight with respect to 30 parts by weight of the photosensitive organic components in the organic vehicle.

E. Production of Green Sheet Molding was performed by a doctor blade method at a molding speed of 0.2 m / min with a spacing of 0.1 to 0.8 mm between the polyester carrier film and the blade in a room where ultraviolet rays were blocked. The thickness of the sheet was 100 μm.

F. Formation of via hole The green sheet was cut into 100 mm square and then dried at a temperature of 80 ° C. for 1 hour to evaporate the solvent. Using a chromium mask with a via diameter of 30 to 100 μm and a via hole pitch of 500 μm, using a super high pressure mercury lamp with an output of 15 to 25 mW / cm ² from the top surface of the sheet, the pattern exposure is performed for 1 minute between the sheet and the mask. did. Next, development was performed with an aqueous solution of 0.5 wt% monoethanolamine maintained at 25 ° C., and then the via hole was washed with water using a spray.

G. Production of Restraint Sheet Used at Firing Polyvinyl butyral, dioctyl phthalate, organic solvent, etc. were added to alumina powder, zirconia powder or magnesia powder, and those produced on the sheet by the doctor blade method were used.

H. Fabrication of Multilayer Substrate Five to six green sheets made of the photosensitive ceramic composition of the present invention were laminated, constraining sheets for non-shrinkage firing were arranged above and below, and thermocompression bonded at 80 ° C. and a press pressure of 15 MPa. The obtained multilayer body was baked in air at a temperature of 900 ° C. for 30 minutes to produce a multilayer substrate.
I. Measurement of total light transmittance Total light transmittance was measured with a haze computer (manufactured by Suga Test Instruments). Measurements were made on three types of sheets having different upper and lower film thicknesses of 50 μm, the straight transmittance and total light transmittance of 50 μm were determined, and the normal transmittance was calculated from the ratio.
J. et al. Evaluation of cracks and cracks In the process up to the lamination press before firing, cracks and chips were evaluated. Evaluation was made with no marks for scratches, Δ for the occurrence of fine scratches or cracks, and x for the occurrence of obvious scratches or cracks.

(Example 1)
Inorganic component I (70%) as inorganic component, polymer (15%), monomer I (5%), urethane compound (5%), photoinitiator (1%), solvent (4%) as photosensitive organic component A green sheet having a thickness of 100 μm was prepared. Table 1 shows the results of measuring the transmittance of the obtained sheet. When via holes were formed by photolithography, 80 μm and 100 μm via holes could be formed. When the lamination pressing was performed together with the alumina constraining sheet, no crack was observed in the multilayer white substrate obtained by baking at 600 ° C. for 30 minutes. Moreover, there was no damage in the bonding process before baking, and workability was favorable. However, because of the strong skin irritation of Monomer I, the hand was irritated.

(Example 2)
Example 1 was repeated except that monomer II was used as the monomer. The transmittance and pattern workability of the obtained sheet were good, and no firing defects occurred.

(Example 3)
Example 1 was repeated except that inorganic component II was used as the inorganic component and monomer III was used as the monomer. The transmittance and pattern workability of the obtained sheet were good, and no firing defects occurred.

Example 4
Example 1 was repeated except that monomer IV was used as the monomer. The transmittance and pattern workability of the obtained sheet were good, and no firing defects occurred.

(Example 5)
Example 2 was repeated except that the urethane compound was replaced with monomer II. The transmittance and pattern workability of the obtained sheet were good. Although slight scratches were observed after firing, no large firing defects occurred.

(Comparative Example 1)
In Example 2, the same composition and trial operation were repeated except that the monomer II was changed to the monomer V to obtain a green sheet having a thickness of 100 μm. Monomer V was a solid wax at room temperature and was difficult to handle. Since the transmittance of the obtained sheet was low, photocuring was insufficient, and the shape of the 80 μm via hole was lacking, which was bad.

(Comparative Example 2)
In Example 2, the same composition and test operation were repeated except that the inorganic component I was changed to the inorganic component III to obtain a green sheet having a thickness of 100 μm. The transmittance of the sheet was very low, and a 100 μm via hole could not be formed with a 100 μm thick green sheet.

  These results are summarized in Table 1.

Claims (5)

In a photosensitive ceramic composition having an inorganic component and a photosensitive organic component as essential components, the inorganic component contains inorganic fine particles having an average particle diameter of 5 nm to 500 nm, and the photosensitive organic component is represented by the general formula (1). A photosensitive ceramic composition comprising a monomer.
^{_{CH 2 = CR 1 -COO- (R}} 2 O) n -OC-R 3 C = CH 2 (1)
(Wherein R ¹ and R ³ are either hydrogen or methyl group, R ² contains at least one alkylene group. N is a natural number of 1 to 15. When n is 2 or more, each R ² Can be the same or different.) The photosensitive ceramic composition according to claim 1, wherein the photosensitive organic component contains a urethane compound. 3. The photosensitive material according to claim 2, comprising 0.1 to 10% by weight of the compound represented by the general formula (1) and 0.1 to 10% by weight of a urethane compound. Ceramic composition. The photosensitive ceramic composition according to any one of claims 1 to 3, wherein the inorganic fine particles having an average particle size of 5 nm to 500 nm are alumina. 5. The photosensitive ceramic composition according to claim 1, comprising 5 to 90% by weight of inorganic fine particles having an average particle diameter of 5 nm to 500 nm.