JP2005249998A - Photosensitive ceramic composition and ceramic multilayer substrate using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive ceramic composition capable of reducing stress due to hardening shrinkage during photolithographic processing and firing by a ring-opening polymerizable compound, and to provide a photosensitive ceramic substrate ensuring reduced warpage and excellent dimensional stability while having alkali developability. <P>SOLUTION: In the photosensitive ceramic composition using a photosensitive organic component and an inorganic powder, the photosensitive organic component includes the ring-opening polymerizable compound. <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 therein must also have excellent high-frequency transmission characteristics in the used frequency band, 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 pattern forming method using a photolithography technique using a green sheet formed from a photosensitive ceramic composition has been proposed (for example, see Patent Document 1).

However, when photolithographic technology is used, photopolymerization of the photosensitive organic component in the photolithographic processing step in pattern formation, and thermal polymerization of the photosensitive organic component in the step of decomposing the organic substance called the debinding step in the baking step. Shrinkage occurred, and problems such as sheet warpage and peeling of the laminate sometimes occurred. On the other hand, a cyclic compound is already known as a compound having small shrinkage at the time of polymerization (for example, see Non-Patent Document 1). However, when these cyclic compounds are used in the photosensitive ceramic composition, there is a problem that they react with an acidic group necessary for developing alkali developability.
JP-A-6-202323 (steps [0036] to [0040]) Endo, “Design of a material that exhibits non-shrinkage during polymerization”, Kagaku Kogyosha, April 1987, p. 253-260

  In order to prevent peeling of the laminate resulting from warpage due to polymerization shrinkage of the photosensitive organic component, it is necessary that curing shrinkage during photopolymerization and thermal polymerization of the composition is small. An object of the present invention is to provide a photosensitive ceramic composition with reduced cure shrinkage.

  That is, the present invention provides a photosensitive ceramic composition comprising a photosensitive organic component and an inorganic powder as essential components, and the photosensitive organic composition contains a ring-opening polymerizable compound. It is a solution.

  According to the photosensitive ceramic composition of the present invention, the ring-opening polymerizable compound can reduce stress due to curing shrinkage during photolithography and firing, so that a photosensitive ceramic substrate with reduced warpage and excellent dimensional stability can be obtained. Can be obtained. Furthermore, according to the photosensitive ceramic composition in which the photosensitive organic component contains a polymer having an acidic group, a photosensitive ceramic substrate having reduced dimensional stability and excellent dimensional stability while having alkali developability is obtained. be able to.

  The photosensitive ceramic composition of the present invention comprises an inorganic powder and a photosensitive organic component as essential components, and the photosensitive organic component contains a ring-opening polymerizable compound.

  The photosensitive organic component of the present invention refers to the total of organic components in the photosensitive ceramic composition. In the photosensitive ceramic composition of the present invention, a solvent is preferably used as a paste body in coating and laminating, but the parameters relating to the composition of the photosensitive organic component (content ratio of each component, etc.) In the following description, in principle, the calculation was performed excluding the solvent component.

  The ring-opening polymerizable compound (component A1) used in the present invention plays an important role in pattern formation by causing a reaction initiated by light, that is, a polymerization reaction.

  In the present invention, examples of component A1 include monomers such as cyclic carbonate compounds, spiroorthoester compounds, spiroorthocarbonate compounds, bicycloorthoester compounds, and oxetane compounds. These are ring-opened by a suitable catalyst, and show substantially no volume change upon crosslinking curing. Cyclic carbonate compounds, spiroorthoester compounds, and oxetane compounds are more preferable from the viewpoints of simple synthesis, ring-opening polymerization under mild conditions, and stability. Further, a polymer in which the ring-opening polymerizable monomer is introduced into the main chain or the side chain may be used. The molecular weight of the polymer is preferably 10,000 to 50,000, more preferably 15,000 to 35,000, and still more preferably 20,000 to 30,000. If it is in the said range, a softness | flexibility is favorable and the solubility at the time of image development is also favorable. The molecular weight is measured using GPC.

  Among the ring-opening polymerizable compounds, those preferably used in the present invention are cyclic carbonate compounds, spiroorthoester compounds, and oxetane compounds. Specifically, as cyclic carbonate compounds, 2-oxo-5 -Acryloyloxymethyl-5-ethyl-1,3-dioxane, 2-oxo-5-acryloyloxymethyl-5-methyl-1,3-dioxane, 2-oxo-5-ethyl-5-methacryloyloxymethyl-1 , 3-dioxane, 2-oxo-5-methyl-5-methacryloyloxymethyl-1,3-dioxane, 2-oxo-5-ethyl-5- (p-vinylbenzyloxy) methyl-1,3-dioxane, 2-Oxo-5-ethyl-5- (m-vinylbenzyloxy) methyl-1,3-dioxane and their p-bi A mixture of rubenzyl and m-vinylbenzyl, 2-oxo-5-methyl-5- (p-vinylbenzyloxy) methyl-1,3-dioxane, 2-oxo-5-methyl-5- (m- Vinylbenzyloxy) methyl-1,3-dioxane and mixtures of these p-vinylbenzyl and m-vinylbenzyl compounds, 2-oxo-5- (p-vinylbenzyl) -1,3-dioxane, 2- As spiro orthoester compounds such as oxo-5- (m-vinylbenzyl) -1,3-dioxane and mixtures of these p-vinylbenzyl and m-vinylbenzyl compounds, 1,4,6-trioxaspiro [4,4] nonane, 2-methyl-1,4,6-trioxaspiro [4,4] nonane, 2-chloromethyl-1,4,6-trioxaspiro [4,4] Nan, 2-phenoxymethyl-1,4,6-trioxaspiro [4,4] nonane, 1,4,6-trioxaspiro [4,4] decane, 2-chloromethyl-1,4,6- Trioxaspiro [4,4] undecane, 2,5-dimethyl-1,4,6-trioxaspiro [4,4] undecane, 2-methylene-1,4,6-trioxaspiro [4,4] Nonane, 2-methylene-1,4,6-trioxaspiro [4,4] undecane, 2-phenyl-1,4,6-trioxaspiro [4,4] undecane, etc. Dimethyloxetane, 3,3-bis (chloromethyl) oxetane, 2-hydroxymethyloxetane, 3-methyl-3-oxetanemethanol, 3-methyl-3-methoxymethyloxetane, 3-ethyl-3 Hydroxymethyloxetane, 3-ethyl-3-phenoxymethyloxetane, resorxinol bis (3-methyl-3-oxetanylethyl) ether, m-xylylenebis (3-ethyl-3-oxetanylethylether), 1,4- Bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, di (3-ethyl-3-oxetanyl) methoxyethyladipic acid, bis (3-ethyloxetan-3-ylmethyl) carbonate, 4,4′-bis [(3-Ethyl-3-oxetanyl) methoxymethyl] biphenyl, 3-ethyl-3-methacryloxymethyloxetane and the like.

  In the present invention, these ring-opening polymerizable compounds (component A1) may be used alone or in combination of two or more. The amount of component A1 added is preferably 10 to 80% by weight in the photosensitive organic component. 10-60 weight% is more preferable, and 15-40 weight% is further more preferable.

  Although the manufacturing method of component A1 is obtained by the method as shown below, it is not limited to this. The compound having a cyclic carbonate is, for example, “Polym. Prepr. Japan” by T. Endo et al., Polymer Society, 1990, Vol. 39, No. 2, p. 284 or T. Endo, “Journal of Polymer Science, Polymer Chemistry Edition” (Polym. Sci. Polym. Chem. Ed.), John Wiley & Sons, Inc, 1991, No. 29, p. In accordance with the method described in 781, etc., the 1,3-propanediol derivative substituted with the corresponding ethylenically unsaturated group and ethyl chlorocarbonate are condensed in the presence of a dehydrochlorinating agent such as triethylamine. It is done.

  Moreover, the compound which has a spiro orthoester group is obtained by reaction of an epoxy compound and lactone, for example. Lactone such as γ-butyrolactone, ε-caprolactone and catalytic boron trifluoride diethyl ether complex is dissolved in an appropriate solvent such as carbon tetrachloride and methylene chloride, and the epoxy compound is dissolved in an appropriate solvent while controlling the reaction temperature. It is obtained by reacting the solution dropwise.

  The oxetane compound is formed by reacting 1,1-bis (chloromethyl) -1- (hydroxymethyl) propane or its acetate with potassium hydroxide in an alcohol solvent diluted with, for example, alcohol or water, and then depositing inorganic The salt was removed by filtration, the solvent was removed by distillation, and further a method of obtaining 3-chloromethyl-3-ethyloxetane by distillation under reduced pressure, an aqueous alkali solution or water suspension in the presence of a phase transfer catalyst. In a liquid, 1,1-bis (chloromethyl) -1- (hydroxymethyl) alkane or a carboxylic acid ester thereof is dehydrochlorinated or deacidified to give 3-chloromethyl-3-alkyloxetane. In the production process or by reacting 1,1,1-tris (hydroxymethyl) propane with diethyl carbonate Give a sulfonate, then the cyclic carbonate is thermally decomposed, a method of obtaining a 3-ethyl-3-hydroxymethyl oxetane is known. Furthermore, diether bisoxetanes are obtained by reacting the corresponding dibromide (xylylene dibromide, ethylene dibromide, etc.) and 3-alkyl-3-hydroxymethyloxetane. Polyether bisoxetanes can be obtained by reacting the corresponding polyethylene glycol (diethylene glycol, triethylene glycol, tetraethylene glycol, etc.) with p-toluenesulfonyl chloride of 3-alkyl-3-hydroxymethyloxetane.

  For example, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane (Aron Oxetane “OXT-212” manufactured by Toagosei Co., Ltd.), 3-ethyl-3-phenoxymethyloxetane (Aron manufactured by Toagosei Co., Ltd.) Oxetane “OXT-211”), 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene (Aron Oxetane “OXT-121” manufactured by Toagosei Co., Ltd.), 3-ethyl-3-hydroxy Methyl oxetane (Aron oxetane “OXT-101” manufactured by Toagosei Co., Ltd.), di (3-ethyl-3-oxetanyl) methoxyethyl adipic acid (“Ubisan bisoxetane adipate”), bis (3 -Ethyloxetane-3-ylmethyl) carbonate ("Dioxetane carbonate" manufactured by Ube Industries, Ltd.), 4,4'-bis [(3-ethyl-3-oxetanyl) methoxy Chill] biphenyl (Ube Industries, Ltd. "ETERNACOLL OXBP"), 3- ethyl-3-methacryloxy oxetane (Ube Industries (Ltd.) "ETERNACOLL OXMA") may be commercially available products such as.

  Component A1 can be polymerized by the ring opening of the cyclic group by either anionic or cationic ionic catalyst. Examples of the cationic catalyst used at this time include boron trifluoride and antimony trifluoride. Lewis acids such as iron trichloride and titanium tetrachloride, Lewis acid complexes such as boron trifluoride diethyl ether complex and boron trifluoride-aniline complex, benzenediazonium tetrafluoroborate, diphenyliodonium tetrafluoroborate, dimethylphena Examples thereof include various onium salts such as silsulfonium tetrafluoroborate and benzyltetramethylenesulfonium hexafluoroantimonate, and methyl trifluoromethanesulfonate. For example, “Optomer SP-150” (produced by Asahi Denka Kogyo Co., Ltd.), “Optomer SP-170” produced by Asahi Denka Kogyo Co., Ltd., “UVE-1014” (manufactured by General Electronics Co., Ltd.), “Lord Sil 2074” Commercial products such as “Rhodia” and “CD-1012” (Sartomer) can also be used.

  Examples of the anionic catalyst include t-butoxy potassium, n-butyl lithium, t-butyl lithium, sodium methoxide and the like.

  When using an ionic catalyst, the usage-amount of a catalyst is 0.001-20 mol% with respect to component A1, Preferably it is 0.1-10 mol%. By adding 0.001 mol% or more, the polymerization of the component A1 can be effectively advanced. On the other hand, if the catalyst concentration exceeds 20 mol%, the catalyst is too much and too expensive, and the usefulness is poor.

  The photosensitive ceramic composition of the present invention preferably contains a polymer having an acidic group. Any polymer having an acidic group may be used, but a polymer having an acidic group composed of a carboxyl group, preferably a polymer having an ethylenically unsaturated group and a carboxyl group in the side chain. (Component A2). By having an ethylenically unsaturated group in the side chain, pattern formation is improved, and by containing a carboxyl group in the side chain, development with an aqueous alkaline solution is possible. Such polymers include, for example, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetate or their anhydrides and methacrylic acid esters, acrylic acid esters, styrene , A monomer such as acrylonitrile, vinyl acetate, 2-hydroxyethyl acrylate and the like, polymerized or copolymerized using a radical polymerization initiator to obtain a polymer, and then a mercapto group which is an active hydrogen-containing group in the polymer, It can be obtained by addition reaction of an ethylenically unsaturated compound having a glycidyl group or an isocyanate group, acrylic acid chloride, methacrylic acid chloride or allyl chloride to an amino group, hydroxyl group or carboxyl group, but is not limited to these is not. Examples of the ethylenically unsaturated compound having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, glycidyl crotonic acid, and glycidyl isocrotonic acid. Examples of the ethylenically unsaturated compound having an isocyanate group include acryloyl isocyanate, methacryloyl isocyanate, acryloylethyl isocyanate, and methacryloylethyl isocyanate. Further, an ethylenically unsaturated compound having glycidyl group or isocyanate group, acrylic acid chloride, methacrylic acid chloride or allyl chloride may be added in an amount of 0.05 to 0.95 mole equivalent to the active hydrogen-containing group in the polymer. preferable. When the active hydrogen-containing group is a mercapto group, amino group, or hydroxyl group, the entire amount can be used for introduction of a side chain group, but in the case of a carboxyl group, it is added so that the acid value of the polymer is within a preferable range. It is preferable to adjust the amount.

  The acid value of component A2 is preferably 50 to 200 mgKOH / g. By setting the acid value to 50 mgKOH / g or more, the solubility of the unexposed area in the developer does not decrease, and by setting the acid value to 200 mgKOH / g or less, the development allowable width can be widened. Component A2 is preferably a copolymer containing acrylic acid ester, methacrylic acid ester, acrylic acid, and methacrylic acid as a copolymerization component because the thermal decomposition temperature during firing is low. The molecular weight of component A2 is preferably 10,000 to 50,000, more preferably 15,000 to 35,000, and still more preferably 20,000 to 30,000. If it is in the said range, a softness | flexibility is favorable and the solubility at the time of image development is also favorable. The molecular weight is measured using GPC.

  The amount of component A2 added is preferably 10 to 80% by weight in the photosensitive organic component. If it is in the said numerical range, pattern formation property and the burning property at the time of baking can be made compatible.

  Usually, a ring-opening polymerizable compound is present simultaneously with a compound having an acidic group such as a carboxylic acid such as a polymer having an ethylenically unsaturated group and a carboxyl group (component A2) in the side chain as preferably used in the present invention. Then, ring opening reaction easily occurs due to heat or the like, and polymerization may occur. However, the cyclic carbonate compound, spiroorthoester compound, and oxetane compound that are preferably used in the present invention are unlikely to occur and are stable. Therefore, it becomes possible to obtain a cured product having a small volume shrinkage during curing while enabling alkali development. Moreover, you may use the polymer which satisfy | fills both component A1 and component A2 as such a compound.

  The photosensitive ceramic composition of the present invention preferably contains an ethylenically unsaturated group-containing compound (component A3) in order to more effectively perform pattern formation with light. The molecular structure of Component A3 is not limited in any way, such as linear, branched, cyclic, or combinations thereof, but is preferably linear from the viewpoint of compatibility. The molecular weight of component A3 is preferably 100 to 100,000, more preferably 100 to 50,000, and still more preferably 300 to 45,000. If it is in the said numerical range, a softness | flexibility is favorable and the solubility at the time of image development is also favorable. The molecular weight is measured using GPC.

  In view of crosslinking reactivity, the ethylenically unsaturated group of component A3 in the present invention is generally preferred to have a small steric hindrance and a large degree of molecular motion. Accordingly, monosubstitution and then disubstitution are preferred. Specific examples include a vinyl group, an allyl group, an acryloyl group, and a methacryloyl group. In particular, it preferably has an acryloyl group or a methacryloyl group.

  Specific examples of the compound having an acryloyl group or a methacryloyl group include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, isobutyl 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, heptadecafluorodecyl acrylate, 2-hydroxy Ethyl acrylate, isobornyl 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, trifluoroethyl acrylate, Acrylamide, aminoethyl acrylate, phenyl acrylate, phenoxyethyl acrylate, 1-naphthyl acrylate, 2-naphthyl acrylate, thiophenol acrylate, benzyl mercaptan acrylate, acrylate of phenol-ethylene oxide adduct, acrylate of paracumylphenol-ethylene oxide adduct , Nylphenol ethylene oxide adduct 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, glycerol diacrylate, methoxylated cyclohexyl diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, triglycerol diacrylate, bisphenol A diacrylate, bisphenol A-ethylene Diacrylate of oxide adduct, Examples include, but are not limited to, diacrylates of bisphenol A-propylene oxide adducts and those in which part or all of these acrylates are replaced with methacrylates.

  Component A3 may have an organic group (bond) in addition to the ethylenically unsaturated group. Examples of such an organic group (bond) include an alkylene oxide group, an alkyl group, an aryl group, an arylene group, an aralkyl group, a hydroxyalkyl group, and a urethane bond. Among these, polar groups such as alkylene oxide, particularly ethylene oxide are preferable from the viewpoint of compatibility. Of the component A1 of the present invention, a compound selected from a cyclic carbonate compound, a spiroorthoester compound, and an oxetane compound that is preferably used differs from the component A2. However, by further containing highly polar ethylene oxide in component A3, it is possible to have both a portion having a polarity close to component A1 and a portion having a polarity close to component A2, and the compatibility of component A1 and component A2 is improved. Can be improved. The ethylene oxide content in such component A3 is preferably 8 to 70% by weight relative to component A3. Among such compounds, a compound containing ethylene oxide and propylene oxide is particularly preferable because of good burn-off.

  The compatibility of the photosensitive organic component can be evaluated by a haze value (cloudiness value). The haze value of the photosensitive organic component is obtained by measuring the haze meter after applying the photosensitive organic component to a glass substrate and drying it. The coating film thickness at this time is 100 μm. In the present invention, the haze value is preferably 10 or less. Within the above range, the compatibility is good and the light transmittance is high, so that photolithography can be effectively performed.

  By using such a compound as a photoreactive component, the compatibility of the photosensitive organic component can be improved and the photolithographic processability can be improved.

  The components A1, A2 and A3 contained in the photosensitive organic component generally have a low ability to absorb the energy of actinic rays, so a photopolymerization initiator is added to initiate the photoreaction. Is preferred. A sensitizer may be used to assist the effect of the photopolymerization initiator. Such photopolymerization initiators are of different types in terms of mechanism, such as single-molecule direct cleavage type, ion-pair electron transfer type, hydrogen abstraction type, and two-molecule complex system. The photopolymerization initiator used in the present invention is preferably one that generates active radical species. One or more photopolymerization initiators and sensitizers can be used. The photopolymerization initiator is preferably added in the range of 0.05 to 10% by weight, more preferably 0.1 to 10% by weight, based on the photosensitive organic component. By setting the addition amount of the photopolymerization initiator within this range, good photosensitivity can be obtained while maintaining the remaining ratio of the exposed portion.

  The photosensitive ceramic composition of the present invention contains an inorganic powder as an essential component in addition to the photosensitive organic component. The inorganic powder contained in the photosensitive ceramic composition of the present invention is sintered in the firing step. In the formation of the substrate intended by the present invention, firing at a temperature of 1000 ° C. or less, particularly 700 to 900 ° C. So-called low-temperature fired inorganic powder is preferred because it is preferred. Of course, since these inorganic powders determine basic physical properties such as electrical characteristics, strength, and thermal expansion coefficient of the substrate, they are selected according to the intended characteristics.

  The component useful as the inorganic powder used in the present invention includes five embodiments.

In the first aspect, the general formula R _x O—Al ₂ O ₃ —SiO ₂ -based material (when x = 1, R is selected from an alkaline earth metal, and when x = 2, R is from an alkali metal). Selected). Although not particularly limited, inorganic powders used as a low-temperature sintered ceramic material, such as anorthite (CaO—Al ₂ O ₃ -2SiO ₂ ), Celsian (BaO—Al ₂ O ₃ -2SiO ₂ ), etc. is there.

  The inorganic powder of the second aspect is composed of 50 to 90% by weight of glass powder and 10 to 50% by weight of quartz powder and / or amorphous silica powder. The glass powder is borosilicate glass. At this time, it is preferable that high-purity silica (quartz) does not dissolve in borosilicate glass or cordierite. Further, spherical silica is preferable because the slurry can be filled more easily.

  Said third embodiment is selected from the group of borosilicate glass powder 30-60% by weight, quartz powder and / or amorphous silica powder 20-50% by weight and cordierite, spinel, forsterite, anorthite and serdian. And a mixture of 20 to 50% by weight of at least one ceramic powder.

A fourth aspect of the above, SiO on an oxide basis notation _2: 30-70 wt%, Al ₂ O _3: 5~40 wt%, CaO: 3 to 25 wt%, B ₂ O _3: 3~50 wt 30 to 60% by weight of a glass powder having a total amount of 85% by weight or more in a composition range of 50% by weight, alumina, zirconia, magnesia, beryllia, mullite, cordierite, spinel, forsterite, anorthite, serzian, silica and It is a mixture with at least one ceramic powder 70 to 40% by weight selected from the group of aluminum nitride.

A fifth aspect of the above, SiO ₂ in terms of oxide notation: 80-90 wt%, B ₂ O _3: 10~15 wt%, Al ₂ O _3: 0~5 wt%, K ₂ O: 0~ It is an inorganic powder contained in a proportion of 5% by weight.

  The inorganic powder can contain a filler component, and ceramic powder is often used as the filler component as described above, which is effective for improving the mechanical strength of the substrate and controlling the thermal expansion coefficient. 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.

Components such as SiO ₂ , Al ₂ O ₃ , CaO and B ₂ O ₃ in the glass powder are preferably 85% by weight or more in the glass powder. The remaining less than 15% by weight can contain Na ₂ O, K ₂ O, BaO, PbO, Fe ₂ O ₃ , Mn oxide, Cr oxide, NiO, Co oxide and the like.

  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 powder and the photosensitive organic component. The refractive index of the inorganic powder 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. It is preferable to match so that | N1-N2 | <0.15, where N1 is the refractive index of the inorganic powder and N2 is the refractive index of the photosensitive organic component.

  The inorganic powder used in the present invention can be fired at 600 to 900 ° C. when Cu, Ag, Au or the like is multilayered as a wiring conductor, and has a thermal expansion coefficient approximate to that of a chip component or a printed circuit board. It is necessary to select a material that provides a substrate having a low dielectric constant and low dielectric loss even in a high frequency region.

  When using a polymer that undergoes polymerization by heat, such as a polymer having an ethylenically unsaturated group in the side chain, stress shrinks due to thermal polymerization during firing (particularly in the temperature range of 150 ° C. to 500 ° C.). Occurs, and the sheet warps. When a monomer or polymer selected from cyclic carbonate compounds, spiro orthoester compounds and oxetane compounds is used as component A1, the warpage rate is 0 to 10%, preferably 0 to 8%, more preferably 0 to 5%. Can be suppressed.

  In the present invention, the warpage rate is defined as follows. When a sheet having a side length of 126 mm square and a film thickness of 150 μm is baked at 400 ° C. and placed on a horizontal table, the maximum warpage amount from the plane is d / 126 × 100. It is defined that

  The sheet used for the measurement of the warpage rate can be produced by processing the photosensitive ceramic composition into a green sheet, irradiating with an actinic ray having an optimum exposure amount, and drying at 70 to 90 ° C. for 10 to 20 minutes. The optimum exposure amount is an exposure amount suitable for forming a via hole.

  The photosensitive ceramic composition is processed into a green sheet, followed by a via hole forming step by photocuring and development, a conductor forming step, and the like, and then laminated and fired to constitute a multilayer ceramic substrate.

  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 that serve as an adhesion improver with an oxidizing agent such as lead oxide, bismuth oxide, zinc oxide, manganese oxide, barium oxide, calcium oxide, strontium oxide, or a glass / ceramic green sheet. It is preferable to add by weight%. Examples of such hard-to-sinter ceramic sheets include adding an organic binder such as polyvinyl butyral and acrylic copolymer to a alumina powder, a plasticizer such as dioctyl phthalate, an appropriate oxide, an organic solvent, etc. What was formed in the sheet form by the blade method can be mention | raise | lifted.

  Inevitable shrinkage exists depending on the components of the composition of the green sheet, the composition of the green sheet, and various conditions during firing. Therefore, if the shrinkage rate can be suppressed to 1% or less, it can be considered that almost no shrinkage has been achieved. 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, etc. 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 restraining sheet disposed on the upper surface of the film. .

  The blending amount of the photosensitive organic component in the photosensitive ceramic composition is preferably 10 to 40% by weight, more preferably 15 to 35% by weight. If it is in the said range, the characteristic of both the flexibility and air permeability of a green sheet can be satisfied.

The photosensitive ceramic composition of the present invention can be prepared as follows. First, a ring-opening polymerizable compound which is a photosensitive organic component, a polymer having a carboxyl group and an ethylenically unsaturated group in the side chain as necessary, a compound having an ethylenically unsaturated group, an ion catalyst, a photopolymerization initiator Then, a solvent, various additives, and the like are mixed and then filtered to prepare an organic vehicle. To this, a pretreated inorganic powder 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 blending ratio of the inorganic powder and the photosensitive organic component, the amount of the organic solvent, and the addition ratio of the plasticizer and other additives, but the range is preferably 1 to 5 Pa · s. The solvent used for constituting the slurry or paste may be any solvent that can dissolve the photosensitive organic component. For example, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, γ-butyrolactone, 3-methylmethoxybutanol, toluene , Trichloroethylene, methyl isobutyl ketone, isophorone, and the like, and organic solvent mixtures containing one or more of them are used. The amount of the solvent contained in the paste varies depending on the intended use and is not limited as long as it falls within the viscosity range. For example, in the application stage, the paste (excluding inorganic powder) ) Is preferably contained in an amount of 10 to 30% by weight. However, it is preferred that the solvent content is substantially zero in the development stage. 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. The green sheet which consists of a ceramic composition is obtained. The via hole is formed by pattern exposure through a photomask having a via hole forming pattern on the green sheet made of 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.

  When the photosensitive organic component of the photosensitive ceramic composition of the present invention contains a polymer having a carboxyl group in the side chain, it can be developed with an alkaline aqueous solution, which is preferable. As the alkali aqueous solution, a metal alkali aqueous solution such as sodium or potassium, or an organic alkali aqueous solution can be used. In this case, the concentration of the alkaline aqueous solution is usually 0.1 to 5% by weight, more preferably 0.5 to 1.5% 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.

  Next, a necessary pattern is formed on the obtained sheet using a conductor, a resistor paste, or the like, such as filling a via hole or forming a wiring. The wiring may be formed by printing with a screen printer or the like, or may be formed by photolithography using a photosensitive conductive paste.

  Next, sheets with the required number of wiring patterns formed thereon are stacked using guide holes and bonded at a temperature of 80 to 150 ° C. and a pressure of 5 to 25 MPa to produce 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 type of inorganic powder and organic component in the photosensitive ceramic composition, but firing is performed in air, in a nitrogen atmosphere, or in a hydrogen reduction atmosphere. In the firing of the photosensitive ceramic composition of the present invention, first, a step of decomposing and scattering organic substances at room temperature to 600 ° C. (debinding step) is performed, followed by sintering 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 photosensitive organic components and inorganic powders used in the examples are as follows.

A. Photosensitive organic component monomer I: 2-oxo-5-ethyl-5-methacryloyloxymethyl-1,3-dioxane (component A1) (trimethylolpropane diketal (50 mmol), diethyl ether in a flask kept at 10 ° C. or lower (50 ml) and triethylamine (100 mmol) were charged, methacrylic acid chloride (50 mmol) was slowly added dropwise thereto, and the mixture was allowed to return to room temperature and reacted for 5 hours. Dimethyl-5-methacryloyloxymethyl-1,3-dioxane (8.0 g) was obtained, methanol (20 ml) was added thereto, concentrated hydrochloric acid (20 mmol) was gradually added in an ice bath, and the mixture was stirred at room temperature for 15 minutes. After solvolysis, the flask was cooled again and the reaction was stopped by adding triethylamine (20 mmol), and then methanol was distilled off under reduced pressure. Then, triethylamine hydrochloride formed by adding diethyl ether was filtered to obtain 2-methacryloyloxymethyl-1,3-propanediol (3.6 g), and the obtained diol was dissolved in tetrahydrofuran (70 ml), After cooling the flask, ethyl chloroformate (36 mmol) and triethylamine (36 mmol) were simultaneously added dropwise thereto, and after completion of the addition, the reaction solution was returned to room temperature and stirred for 5 hours. Was distilled off under reduced pressure and recrystallized from diethyl ether to obtain white crystals (2.4 g).
Monomer II: Spiro compound A (component A1) (methylene chloride (200 ml) and γ-butyrolactone lactone (1.2 mol) were added to a four-necked flask, cooled to about 10 ° C., boron trifluoride diethyl ether complex (0.8 Next, a mixed solution of naphthalene skeleton type epoxy compound “HP-4032” (Dainippon Ink Chemical Co., Ltd.) (0.4 mol) and methylene chloride (100 ml) was added dropwise with stirring over 1 hour. Further, after reacting at room temperature for 4 hours, triethylamine (1.6 ml) was added, and the reaction solution was washed with 5% aqueous sodium hydroxide solution, and the organic layer was extracted to obtain the desired product.
Monomer III: 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene (Aron Oxetane “OXT-121” manufactured by Toagosei Co., Ltd.) (component A1)
Monomer IV (component A3): polyethylene glycol diacrylate (“M-245”: manufactured by Toagosei Co., Ltd.)
Monomer V (component A3): urethane acrylate “UV6100B” (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.)
Polymer I: 3-ethyl-3-methacryloxymethyloxetane (Ube Industries, Ltd. “ETERNACOLL OXMA”) 40%, 2-ethylhexyl acrylate 40%, methacrylic acid 20% copolymer (component A1). Weight average molecular weight: 20000, acid value: 140 (3-ethyl-3-methacryloxymethyloxetane, 2-ethylhexyl acrylate, methacrylic acid, azoisobutyronitrile dissolved slowly in a solvent kept at 75 ° C. It is obtained by reacting for a time.)
Polymer II: a product obtained by addition reaction of 0.4 equivalent of glycidyl methacrylate to the carboxyl group of a copolymer composed of 30% styrene, 30% methyl methacrylate and 40% methacrylic acid (component A2). Weight average molecular weight 30000, acid value 110 (Styrene, methyl methacrylate, methacrylic acid, azoisobutyronitrile dissolved in a solvent kept at 75 ° C. was slowly dropped, reacted for 5 hours, glycidyl methacrylate, tetrabutylammonium chloride It is obtained by slowly dropping p-methoxyphenol dissolved therein and reacting for 3 hours.)
Polymer III: “Cyclomer P (ACA) 250” (component A2) manufactured by Daicel UCB Ltd. (obtained by addition reaction of 3,4-epoxycyclohexyl methacrylate to a copolymer of methacrylic acid and methyl methacrylate) ), Weight average molecular weight 10,000, acid value 75
Polymer IV: a copolymer comprising 35% ethyl acrylate, 35% 2-ethylhexyl acrylate and 30% methacrylic acid. Weight average molecular weight 25000, acid value 160
Photopolymerization initiator: 2-benzyl-dimethylamino-1- (4-monoforinophenyl) -butanone-1 (“Irgacure 369” manufactured by Ciba Specialty Chemicals)
Ring-opening polymerization catalyst: aromatic sulfonium salt initiator (“SP-172” manufactured by Asahi Denka Kogyo Co., Ltd.)
UV light absorber: Sudan IV (manufactured by Tokyo Chemical Industry Co., Ltd.)
Polymerization inhibitor: p-methoxyphenol (Wako Pure Chemical Industries, Ltd.)
B. Inorganic powder Inorganic powder I:
Composite ceramics of 55% alumina powder + 45% glass powder Characteristics of the above-mentioned alumina powder: average particle size 2 μm
Composition of the glass powder: SiO ₂ (60.0%), PbO (17.5%), CaO (7.5%), MgO (3.0%), Na ₂ O (3.15%), K ₂ O (2%), B ₂ O ₃ (5.8%)
Properties of the above 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 powder II:
Composite ceramics of 50% alumina powder + 50% glass powder Characteristics of the above alumina powder: average particle size 37 nm
Composition of the glass powder: SiO ₂ (60.0%), PbO (17.5%), CaO (7.5%), MgO (3.0%), Na ₂ O (3.15%), K ₂ O (2%), B ₂ O ₃ (5.8%)
Properties of the above 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 powder III:
Composite ceramics of 25% alumina powder + 75% glass powder Characteristics of the above-mentioned alumina powder: average particle size 2 μm
Composition of the glass powder: Al ₂ O ₃ (8.7%), SiO ₂ (67%), ZrO ₂ (2.7%), K ₂ O (1.6%), B ₂ O ₃ (12. 5%)
Properties of the above glass powder: glass transition point 500 ° C., thermal expansion coefficient 42 × 10 ⁻⁷ / K, dielectric constant 4.7 (1 MHz), average particle diameter 3 μm
Inorganic powder IV:
Composite ceramics of Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ glass powder 85% + quartz 15% Composition of the above glass powder: Al ₂ O ₃ (1.87%), SiO ₂ (67.3%), K ₂ O (1.22%), B ₂ O ₃ (11.8%),
Properties of the above glass powder: glass transition point 507 ° C., thermal expansion coefficient 46 × 10 ⁻⁷ / K, dielectric constant 4.6 (1 MHz), average particle size 2.2 μm
Inorganic powder V:
Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ glass powder Composition of the above glass powder: Al ₂ O ₃ (0.34%), SiO ₂ (84.3%), K ₂ O (1.29%) , B ₂ O ₃ (11.7%),
Properties of the above glass powder: glass transition point 509 ° C., thermal expansion coefficient 22 × 10 ⁻⁷ / K, dielectric constant 4.5 (1 MHz), average particle diameter 2.5 μm
Inorganic powder VI:
Composite ceramics with 50% alumina powder + 50% glass powder ("NKX-592J" (manufactured by Nippon Fellow))
Characteristics of the alumina powder: Average particle size 2 μm
Composition of the glass powder: Al ₂ O ₃ —B ₂ O ₃ —SiO ₂ —CaO-based glass Properties of the glass powder: Average particle diameter 4.8 μm,
Inorganic powder VII:
Alumina / crystalline glass composite ceramics (“FJ352J” (manufactured by Nippon Fellow))
Composition of the glass powder: Al ₂ O ₃ —B ₂ O ₃ —SiO ₂ —CaO—ZnO-based glass Properties of the glass powder: glass transition point 683 ° C., thermal expansion coefficient 52 × 10 ⁻⁷ / K, average particle diameter 5 μm
Inorganic powder VIII:
Crystalline glass ("FJ351J" (Nippon Fellow Co., Ltd.))
Composition of the glass powder: Al ₂ O ₃ —B ₂ O ₃ —SiO ₂ —MgO-based glass Properties of the glass powder: glass transition point 681 ° C., thermal expansion coefficient 90 × 10 ⁻⁷ / K, average particle diameter 5 μm
Inorganic powder IX:
Amorphous glass ("K805" (Asahi Techno Glass Co., Ltd.))
The composition of the glass _{powder: Al 2 O 3 -B 2 O} 3 -SiO 2 based glass inorganic powder X:
Mixture of 80% glass powder and 20% SiO ₂ Composition of the above glass powder: Al ₂ O ₃ —B ₂ O ₃ —SiO ₂ glass.

C. Developer solution I: 1.5% aqueous solution of sodium carbonate 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 photopolymerization initiator were added and dissolved. The solution was vacuum degassed and then filtered through a 250 mesh filter to produce an organic vehicle.

E. Paste preparation Inorganic powder was mixed with the above organic vehicle, and wet mixed with a ball mill for 20 hours to form a slurry or paste. The amount of the inorganic powder was 75 parts by weight with respect to 25 parts by weight of the photosensitive organic components in the organic vehicle.

F. Production of Green Sheet In a room where ultraviolet rays are blocked, the distance between the polyester carrier film and the blade is 0.1 to 0.8 mm, and the molding speed is 0.2 m / min. A green sheet was prepared by the doctor blade method. The thickness of the sheet was 150 μm.

G. Formation of via hole The green sheet was cut into 126 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, it developed with the developing solution hold | maintained at 25 degreeC, Then, the via hole was washed with water using the spray.

H. Measurement of Warpage Rate After firing a sheet having a side length of 126 mm square and a film thickness of 150 μm at 400 ° C., the maximum warpage amount d from the plane is measured on a horizontal base, and the calculation formula warpage rate (%) = It calculated in d / 126x100. A case where the warpage rate was 10% or less was judged as ◯, and a case where the warpage rate exceeded 10% was judged as x.

I. Production of Restraint Sheet Used for Firing Polyvinyl butyral, dioctyl phthalate, organic solvent, etc. were added to alumina powder, zirconia powder, or magnesia powder, and a sheet produced by a doctor blade method was used.

J. et al. 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 disposed above and below, and thermocompression bonded at 90 ° 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. The firing shrinkage (%) was measured in the XY plane direction.

Example 1
Inorganic powder I (80%) as inorganic powder, polymer II (12%), monomer I (4%), monomer IV (2%) and photopolymerization initiator (1%) as photo-sensitive organic components, ring opening A green sheet having a thickness of 150 μm was obtained using a polymerization catalyst (0.8%), an ultraviolet light absorber (0.02%), and a polymerization inhibitor (0.18%). The warpage rate was measured and found to be 5%. The firing shrinkage was as low as 0.3%.

Examples 2-19
The procedure of Example 1 was repeated using the components shown in Table 1. The results are shown in Tables 1 and 2. In all the examples, the firing shrinkage ratio was as small as 0.3%.

Comparative Example 1
Implemented except that Polymer II (18%), photopolymerization initiator (1.8%), UV light absorber (0.02%), and polymerization inhibitor (0.18%) were used as the photosensitive organic component. The same operation as Example 1 was repeated. The warpage rate of the obtained sheet was 15%. When firing using an alumina constraining sheet, the constraining sheet peeled off and no shrinkage firing was possible. The firing shrinkage rate could not be measured due to warpage.

Comparative Example 2
Polymer II (12%), monomer V (6%) and photopolymerization initiator (1.8%), ultraviolet light absorber (0.02%), polymerization inhibitor (0.18%) as photosensitive organic components The same operation as in Example 1 was repeated except that was used. The warpage rate of the obtained sheet was 20%. When firing using an alumina constraining sheet, the constraining sheet peeled off and no shrinkage firing was possible. The firing shrinkage rate could not be measured due to warpage.

Claims (6)

A photosensitive ceramic composition comprising a photosensitive organic component and an inorganic powder as essential components, wherein the photosensitive organic component contains a ring-opening polymerizable compound. 2. The photosensitive ceramic composition according to claim 1, wherein the photosensitive organic component contains a polymer having an acidic group. The photosensitive ceramic composition according to claim 2, wherein the acidic group comprises a carboxyl group. 4. The photosensitive ceramic composition according to claim 3, wherein the photosensitive organic component contains a polymer having a carboxyl group and an ethylenically unsaturated group in the side chain and / or an ethylenically unsaturated group-containing compound. The photosensitive ceramic composition according to any one of claims 1 to 4, wherein the ring-opening polymerizable compound is any one of a cyclic carbonate compound, a spiroorthoester compound, and an oxetane compound. A ceramic multilayer substrate using the photosensitive ceramic composition according to claim 1.