JPH061653A - Ceramics green sheet - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a ceramics green sheet which is excellent in strength and handleability and is also excellent in debinding property in both oxidizing atmosphere and non-oxidizing atmosphere. [Structure] 80% by weight or more of a methacrylate unit selected from the group consisting of butyl methacrylate, a C 8 or more methacrylate having an alkyl side chain at the β-position, a hydroxyl group-containing methacrylate and a cycloalkyl group-containing methacrylate, A ceramics green sheet is obtained from ceramic powder using a binder composed of a methacrylate-based copolymer having a butyl methacrylate unit content of 50% by weight or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramics green sheet which is preferably used for forming a sintered ceramics substrate or the like, and more specifically to a high density mounting in which semiconductor elements are mounted and they are mutually wired. The present invention relates to a green sheet made of a ceramic preferably used for a fired ceramics substrate, particularly a multilayer ceramic substrate.

[0002]

2. Description of the Related Art Multi-layer ceramic substrates are roughly classified into a thick film printing lamination method and a green sheet method. Further, the green sheet method includes a laminating method and a printing method. In the green sheet printing method, conductive paste and insulating paste are alternately printed and laminated on the green sheet to form a multilayer,
After repeating printing and drying, firing is completed once. The green sheet lamination method is almost the same as the green sheet printing method, but when multilayering it, a large number of green sheets on which conductors have been printed and via-hole processed have been laminated, thermocompression bonded, and fired. It is a method of forming a multilayer substrate.

Conventional ceramics green sheets are
Normally, as described in JP-A-51-190009, JP-B-3-5075, JP-B-3-53269, JP-A-2-141458, JP-A-1-201063 and JP-A-64-87549. , Ceramic powder, an organic binder, a plasticizer, a solvent and, if necessary, a dispersant and the like are appropriately mixed, and then mixed to form a slurry, and the obtained slurry is formed into a sheet by a known method such as a doctor blade method. It is made. In this case, as the organic binder, which will be described in detail later, polyvinyl butyral,
Butyl methacrylate resin, polymethylmethacrylate resin, etc. are used.

In recent years, high-frequency and high-speed signal processing (corresponding to the age of digitization), high-density mounting of LSI and miniaturization of AV (audio / video), personal computers, mobile phones, etc. have made it necessary to reduce the resistance of conductor circuits. Is increasing.
In addition to the low resistance of the conductor circuit, conductors such as copper, tungsten, and molybdenum have low resistance and migration (the electrode conductor reacts with a small amount of water and is ionized and moves toward the opposing electrode, which causes It is attracting attention as the most promising conductor because there is little phenomenon that insulation resistance decreases. In the case of the green sheet lamination method or the printing method, the above conductor such as copper is used for forming the circuit of the conductors of the inner layer and the surface layer of the ceramics green sheet multilayer substrate, and especially when used as the inner layer conductor, It is necessary to fire the ceramics and green sheets at the same time. Moreover, the number of layers of the green sheet is multi-layered from 5 to 150 due to the demand for miniaturization and high-density mounting of supercomputers, personal computers, AVs, mobile phones, etc., and a large amount of organic binder is also contained.

However, when a conductor such as copper is burned in an oxidizing atmosphere, copper or the like is oxidized, so it is necessary to burn the conductor in a non-oxidizing atmosphere. Therefore, it is necessary to fire the green sheet at the same time as the conductor such as copper in a non-oxidizing atmosphere.
For that purpose, the organic binder used in forming the green sheet must be removed by firing in a non-oxidizing atmosphere.

The above-mentioned acrylate-methacrylate copolymers described in JP-A-1-201063 and JP-A-51-
The binder such as polyvinyl butyral resin described in JP-A-190909 is oxidized and removed when baked in an oxidizing atmosphere, but decomposition and scattering of the organic binder are insufficient when baked in a non-oxidizing atmosphere. Therefore, there is a problem that a large amount of carbon remains in the ceramic multilayer substrate after firing, causing insulation failure of the substrate. In the case of a conventionally proposed green sheet containing an organic binder that can be fired in a non-oxidizing atmosphere, there are problems such as low strength of the green sheet and poor handleability. It is also needed to raise. Furthermore, when a conventional green sheet is made into a multi-layer green sheet,
Since it takes 3 weeks, there is a drawback that the cost becomes high.

On the other hand, as the ceramic powder used for the ceramic green sheet, alumina (Al ₂ O
₃ ), zirconia (ZrO ₂ ), magnesia (Mg
O), mullite _{(3Al 2 O 3 · 2SiO 2} ), anorthite _{(CaO · Al 2 O 3 ·} 2SiO 2), forsterite (2MgO · _SiO 2), celsian (BaO
・ Al ₂ O ₃・ 2SiO ₂ ) and spinel (MgO ・ Al)
₂ O ₃ ), cordierite (5SiO ₂ · 2Al ₂ O ₃
・ 2MgO), Clinoenstatite (MgO ・ SiO)
₂ ), powders of silica (SiO ₂ ), etc., or low-temperature fired ceramic powders such as SiO ₂ —B ₂ O ₃ -based to P
_{bO-SiO 2 -Al 2 O 3} -B 2 O 3 based glass, Ca
_{O-SiO 2 -Al 2 O 3} -B 2 O 3 system, such as a glass A
l ₂ O _3, quartz _{(SiO 2),} ZrO 2, glass was added ceramic component such as cordierite - ceramic composite system or _MgO-Al 2 O 3 -SiO ₂ system and _Li 2 O-
Al ₂ O ₃ —SiO ₂ -based crystallized glass or the like is used. Crystallized glass for example _MgO-Al 2 O 3 -Si
The O ₂ by addition of _B 2 _{O 3} and nucleating agent, 900 ° to 10
It is fired at 00 ° C. to precipitate cordierite crystals for higher strength, and Li ₂ O—Al ₂ O ₃ —SiO ₂ is added with B ₂
A material in which O ₃ and a nucleating substance are added to precipitate spodumene to increase the strength is also used.

Conventional organic binders include polyvinyl alcohol, polyvinyl butyral, methacrylic acid ester polymers, acrylic acid ester polymers, acrylic acid ester-methacrylic acid ester copolymers, α-methylstyrene polymers, butyl methacrylate resins, etc. Is used as a plasticizer, dibutyl phthalate, dioctyl phthalate, polyethylene glycol, glycerin, etc. are used, and as a solvent, alcohol, toluene, acetone, methyl ethyl ketone, butanol, trichloroethylene, methyl isobutyl ketone, isophorone, etc. are used. ing.

The obtained green sheet is processed into a desired shape by a cutter or a punching die, and then a green sheet is punched to form a via hole and a through hole (hereinafter referred to as a via hole). Drilling with a mold or laser. For example, in the production of a multilayer substrate by the green sheet multilayer lamination method, a slurry, which is a raw material for a green sheet, is continuously thinly spread on a carrier film to form a green sheet, and then the carrier film is peeled and removed from the back surface of the green sheet. Then, the green sheet is punched into a required work size, the green sheet is perforated to form a via hole, and the conductive paste is filled in the via hole by a normal screen printing method. If the thickness of the green sheet is less than 50 μm, make a hole with the carrier film.
Formed a via hole.

[0010]

SUMMARY OF THE INVENTION The present invention was devised in view of various drawbacks of the ceramic green sheet in which a conductor such as copper is used for the inner layer of the green sheet and is fired in a non-oxidizing atmosphere in the prior art. It is an object of the present invention to provide a ceramics green sheet containing a novel organic binder by solving the drawbacks of the conventional ceramics green sheet.

[0011]

The object of the present invention is as follows.
80% by weight or more of a methacrylate unit selected from the group consisting of ceramic powder and butyl methacrylate, a C 8 or more methacrylate having an alkyl side chain at the β-position, a hydroxyl group-containing methacrylate and a cycloalkyl group-containing methacrylate, This is achieved by a ceramics green sheet characterized by containing a methacrylate-based copolymer having a butyl methacrylate unit content of 50% by weight or more.

In the above, the ceramic powder is alumina, zirconia, magnesia, beryllia, mullite,
It is more preferably achieved by a ceramic green sheet containing at least one selected from the group consisting of cordierite, spinel, forsterite, anorthite, cergian, clinoenstatite and silica.

In the above, the ceramic powder is expressed in terms of oxides: SiO ₂ 30 to 70% by weight Al ₂ O ₃ 6 to 25% by weight CaO 5 to 25% by weight MgO 1 to 10% by weight B ₂ O _{3 3 to} 50% by weight % TiO ₂ 1 to 15% by weight, 40 to 60% by weight of glass composition powder with a total amount of 95% by weight or more, and alumina, zirconia, magnesia, beryllia, mullite, cordierite, forsterite, spinel, anor. It is more preferably achieved by a ceramics green sheet characterized by being a raw material mixture with 60 to 40% by weight of at least one kind of inorganic filler powder selected from the group consisting of site, celdian, clinoenstatite and silica.

The binder used in the ceramic green sheet of the present invention is easily decomposed / scattered even under the firing / sintering conditions of the green sheet moldability, strength and thermal decomposability, especially in a non-oxidizing atmosphere, and It is less likely to remain as undecomposed carbide in the sheet, and the methacrylate is butyl methacrylate, a methacrylate having 8 or more carbon atoms and an alkyl side chain at the β-position,
A methacrylate-based copolymer having a methacrylate unit selected from a hydroxyl group-containing methacrylate and a cycloalkyl group-containing methacrylate occupying 80% by weight or more and having a butyl methacrylate unit content of 50% by weight or more. To do. Needless to say, a copolymer is a polymer having two or more kinds of monomer components, and specifically, two or more kinds of butyl methacrylate are used as comonomer components, or at least one of butyl methacrylate and other than butyl methacrylate are used. It contains the above-mentioned methacrylate as a comonomer component.

Butyl methacrylate as the main monomer unit of the methacrylate-based copolymer, methacrylate having 8 or more carbon atoms having an alkyl side chain at the β-position, hydroxyl group-containing methacrylate and cycloalkyl group-containing methacrylate are selected because they are monomers. The polymer contained as a unit is easily depolymerized and easily depolymerized even when heated in a non-oxidizing atmosphere and decomposed / scattered. When these monomer units account for 80% by weight or more, green sheet moldability, This is because when the content of the butyl methacrylate unit, which is excellent in strength, handleability and thermal decomposability and is excellent in depolymerization, is 50% by weight or more, the thermal decomposability becomes particularly good.

In the present invention, the content of the monomer unit in the copolymer is shown by weight%, which is the weight% converted to the monomer used. The methacrylate-based copolymer of the present invention has a total content of butyl methacrylate, a hydroxyl group-containing methacrylate, a C8 or more methacrylate having an alkyl side chain at the β-position and a cycloalkyl group-containing methacrylate of 80% by weight or more, preferably 90
The total content of butyl methacrylate is 5% by weight or more.
It is necessary to be 0% by weight or more, preferably 60% by weight or more, whereby the copolymer is liable to depolymerize, and it is easy not only when it is heated in an oxidizing atmosphere but also in a non-oxidizing atmosphere. The effect of depolymerizing, decomposing / scattering, and making it hard to remain as a carbide is obtained.

Here, as butyl methacrylate, n-
Butyl methacrylate, isobutyl methacrylate, s
Examples thereof include ec-butyl methacrylate and tert-butyl methacrylate. Among them, isobutyl methacrylate is preferable because it has excellent thermal decomposability and is contained in an amount of 50% by weight or more as a butyl methacrylate monomer unit. 50% by weight of isobutyl methacrylate as a monomer unit
When it is below the range, good thermal decomposability cannot be obtained under particularly severe non-oxidizing atmosphere conditions.

Specific examples of the methacrylate having an alkyl side chain at the β-position and having at least 8 carbon atoms include 2-methylbutyl methacrylate, 2-methylpentyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, isodecyl methacrylate and iso Examples thereof include lauryl methacrylate and isostearyl methacrylate. Among them, 2-ethylhexyl methacrylate is particularly preferable.

Specific examples of the hydroxyl group-containing methacrylate include 2-hydroxyethyl methacrylate and 2-hydroxyethyl methacrylate.
Hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, glycerol monomethacrylate, trimethylolpropane monomethacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate and the like can be mentioned. Among them, 2 is particularly preferable. -Hydroxyethyl methacrylate, 2
-Hydroxypropyl methacrylate. Specific examples of the cycloalkyl group-containing methacrylate include cyclohexyl methacrylate, cycloheptyl methacrylate, cyclooctyl methacrylate,
Of these, cyclohexyl methacrylate is particularly preferred. The methacrylate-based copolymer of the present invention may contain monomer components other than the above. As the comonomer component other than the above, a copolymerizable unsaturated carboxylic acid,
Acrylate-based monomers and / or styrene-based monomers are preferable in terms of green sheet moldability, strength, and handleability.

As the unsaturated carboxylic acid, acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid,
Maleic acid half-esters such as maleic acid monoisopropyl are used as acrylate monomers such as ethyl acrylate, butyl acrylate, 2-methoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate,
Examples include dimethylamino acrylate, and examples of the styrene-based monomer include styrene, α-methylstyrene, β-methylstyrene, α-ethylstyrene, β-ethylstyrene, and vinylstyrene. Comonomer components other than these may also be contained. Examples of these include methacrylate, methacrylonitrile, acrylamide, vinyl acetate, vinyl chloride and the like other than the above. Specific examples of methacrylates other than the above include methyl methacrylate, ethyl methacrylate, propyl methacrylate,
There are 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate and the like.

When using a comonomer as an optional component, if the content in the methacrylate copolymer exceeds 20% by weight, the thermal decomposability or copolymerizability is hindered, so the content must be kept below 20% by weight. There is. Among these comonomer components, unsaturated carboxylic acid has the effect of imparting an appropriate acid value to the methacrylate-based copolymer to enhance the dispersibility and dispersion stability of the ceramic powder, improving the green sheet moldability, strength and handleability. For this purpose, it is desirable to use in combination of preferably 10% by weight or less, more preferably 0.1 to 5% by weight. Particularly preferred is methacrylic acid. The preferred acid value of the copolymer varies depending on the type of ceramic powder used, polarity, acidity, basicity, amount of acid, etc., so it is desirable to select the optimum value according to them. If the acid value becomes too high, the decomposition / scattering property at the time of debinding will tend to deteriorate, so the acid value should be adjusted to the range of 0.1 to 20, preferably 1 to 10. Further, the styrene-based monomer has excellent depolymerizability, and has an effect of lowering the decomposition temperature of the methacrylate-based copolymer composition, 20% by weight.
It is also possible to add up to. Particularly preferred is α-
It is methylstyrene. Acrylic monomers such as propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate can be used in small amounts for the purpose of improving green sheet moldability such as glass transition temperature adjustment and handling, but the copolymer of acrylate monomers is methacrylate. Since the depolymerizability is inferior to that of a copolymer of a system monomer, the addition amount thereof is desirably controlled to 10% by weight or less, preferably 5% by weight or less.

The polymerization method for obtaining the methacrylate copolymer of the present invention is not limited at all, but the most general method is the presence of a radical polymerization initiator such as peroxide, hydroperoxide or azoisobutyronitrile. In addition, a usual polymerization method such as suspension polymerization, solution polymerization, emulsion polymerization and the like is adopted, and the reaction is usually carried out at -10 to 150 ° C for several minutes to several hours. In this case, if necessary, a chain transfer agent can be further added during the polymerization reaction, and the molecular weight is preferably adjusted by the catalyst amount, the monomer concentration and the like.

The effect of the methacrylate copolymer used in the present invention varies depending on the molecular weight. The optimum molecular weight varies depending on the specific surface area, particle size, particle size distribution, etc. of the ceramic powder, so it is desirable to select it according to these, but generally the molecular weight determined by the following method is from 1,000 to 1,000,000. The content of the copolymer within the range occupies 80% or more, preferably 90% or more, more preferably 95% or more, and is less than the optimum standard value of 50,000 to 200,000 in the molecular weight range. The content ratio of the copolymer having a molecular weight to the copolymer having a molecular weight exceeding the standard value is within the range of 1/1 to 9/1, preferably 2/1 to 5/1. The preferred value selected as the reference molecular weight is 150,000. If the proportion of the low molecular weight substances and the high molecular weight substances outside the above molecular weight range exceeds 10% by weight, when the amount of the low molecular weight substances is too much, the performance as a binder becomes insufficient and satisfactory green sheet moldability is obtained. On the other hand, when the amount of the high molecular weight substance is too large, the decomposition / burning property at the time of debinding is deteriorated, and the amount of the carbides remaining in the ceramic sheet becomes so large that it cannot be ignored. Further, even if the content ratio within the above preferable molecular weight range satisfies the above requirements, the content ratio with the copolymer on the low molecular weight side with respect to the optimum reference value molecular weight of 50,000 to 200,000 exceeds the above range. In that case, the green sheet moldability becomes poor, while when the content ratio with the high molecular weight copolymer exceeds the above range, the amount of carbide remaining in the ceramic sheet increases.

The methacrylate copolymer used in the present invention can fulfill its purpose regardless of other requirements as long as it satisfies the requirements such as the selected monomer, the content rate of the monomer unit and the molecular weight. However, the number average molecular weight is 5 in order to further improve the green sheet moldability, shape retention and handleability, and easy decomposability upon debinding.
000 to 100,000, preferably 10,000 to 60,000,
And the glass transition temperature is 0 to 80 ° C., preferably 20 to 6
It is desired to be 0 ° C.

The ceramic powder used in the present invention is not particularly limited, and known ceramic insulating materials such as those for low temperature firing can be appropriately used, but the more effective ceramic powder in the present invention is alumina, zirconia, magnesia, beryllia, Mullite, cordierite, spinel,
It is at least one selected from the group consisting of forsterite, anorthite, Sergian, clinoenstatite and silica.

More preferable ceramic powders used in the present invention are, for example, SiO ₂ and Al.
Glass composition powder containing ₂ O ₃ , CaO, B ₂ O ₃ and optionally MgO and TiO ₂ , and alumina, zirconia, magnesia, beryllia, mullite, cordierite, forsterite, spinel, anorthite, sergian and clino. A raw material mixture with at least one inorganic filler powder selected from the group of enstatite silica is used. SiO ₂ more preferably ceramic powder in terms of oxide title 30-70 wt% _Al 2 _O 3 6~25 wt% CaO 5 to 25 wt% MgO 1 to 10 wt% _B 2 _O 3 3~50 wt% TiO ₂ In the composition range of 1 to 15% by weight, 40 to 60% by weight of glass composition powder having a total amount of 95% by weight or more, and alumina, zirconia, magnesia, beryllia, mullite, cordierite, forsterite, spinel, anorthite, sergian. , 60 to 40% by weight of at least one inorganic filler powder selected from the group consisting of clinoenstatite and silica.

The inorganic filler is effective in improving the mechanical strength of the substrate and controlling the coefficient of thermal expansion, and particularly alumina, zirconia, mullite, cordierite and anorthite are excellent in that effect. The ratio of inorganic filler is 6
If it exceeds 0% by weight, it becomes difficult to sinter, and it becomes impossible to sinter at 1000 ° C or lower. On the other hand, if it is less than 40% by weight, control of the thermal expansion coefficient and a substrate having a low dielectric constant cannot be obtained. Further, the composition range of the glass is preferably such that SiO ₂ is in the range of 30 to 70% by weight, and when it is less than 30% by weight, the strength and stability of the glass layer are lowered, and the dielectric constant and the thermal expansion coefficient are high. It deviates from the desired value. On the other hand, if it exceeds 70% by weight, the coefficient of thermal expansion of the fired substrate becomes high, and firing at 1000 ° C. or lower becomes difficult. Furthermore, Al ₂ O
₃ is preferably mixed in the range of 6 to 25% by weight.
If it is less than 6% by weight, the strength in the glass phase will be reduced and 1
It becomes difficult to fire at 000 ° C or lower. If it exceeds 25% by weight, the temperature for fritizing the glass composition becomes too high. CaO is preferably added in the range of 5 to 25% by weight. If it is less than 5% by weight, the desired coefficient of thermal expansion cannot be obtained, and firing at 1000 ° C. or less becomes difficult, and if it exceeds 25% by weight, the dielectric constant and the coefficient of thermal expansion become large. MgO is preferably added in the range of 1 to 10% by weight, which facilitates control of the melting temperature of the glass. If it exceeds 10% by weight, the coefficient of thermal expansion of the obtained substrate increases. B ₂ O ₃ is 1300-1 glass frit
Since it melts at a temperature near 450 ° C and the firing temperature of ceramics is high even if Al ₂ O ₃ is large, the electrical, mechanical and thermal characteristics such as dielectric constant, strength, coefficient of thermal expansion and sintered density are not impaired. In order to control the firing temperature in the range of 800 to 1000 ° C., it is preferable to mix the calcination temperature in the range of 3 to 50% by weight. If it is less than 3% by weight, the strength of the ceramics tends to be lowered if the content of B ₂ O ₃ is too large, and if it exceeds 50%, the stability of the glass is lowered and recrystallization due to the reaction between the inorganic filler (crystal) and the glass is caused. Get faster If it exceeds 50% by weight, the phenomenon that the glass phase oozes out easily occurs when a multilayer substrate is formed.

TiO ₂ is preferably blended in the range of 1 to 15% by weight. The low temperature fired ceramics substrate of the present invention is a mixture of amorphous glass and inorganic filler before firing, but depending on the kind of filler, it is partially crystallized ceramics of amorphous glass, ceramics and crystallized glass. It is estimated to be. TiO ₂ acts as an effective nucleating substance in the formation of crystallized glass, and the effect is particularly remarkable in the above range.

Alumina, zirconia, magnesia, beryllia, mullite, based on 40 to 60% by weight of glass powder.
At least one inorganic filler powder selected from cordierite, forsterite, spinel, anorthite, cergian, clinoenstatite and silica is added to the powder 6
It has been described above that the raw material mixture added with 0 to 40% by weight is preferable, but by setting the amount of the inorganic filler powder within this range, the firing temperature of the ceramics is set to 800 to 1000 ° C., and the strength, the dielectric constant, the thermal expansion coefficient, and the firing are set. Desired properties can be the consolidation density, volume resistivity, and shrinkage rate.

The glass powder in combination with the inorganic filler usually contains 0 to 5% by weight of Na ₂ O, K ₂ O, as impurities.
It can contain BaO, PbO, Fe ₂ O ₃ , Mn oxide, Cr oxide, NiO, Co oxide. The inorganic filler powder combined with the glass powder may also contain the same impurities as the above-mentioned glass powder up to 5% by weight. Typical examples of the glass manufacturing method are raw materials SiO ₂ , Al ₂ O ₃ , and C.
aO, MgO, B ₂ O ₃ , and TiO ₂ are mixed so as to have a predetermined composition, and melted at 1250 to 1450 ° C., then rapidly cooled, made into a glass frit, and then ground to 0.5 to 3 μ.
It is a method of making fine powder of m. As the raw material, high-purity carbonate, oxide, hydroxide or the like can be used. Depending on the type and composition of the glass powder, 99.99% or more ultra-high-purity alkoxide or organometallic solution raw materials are used, and sol.
If you use a powder made homogeneously by the gel method, it has a low dielectric constant,
It is preferable because a dense and high-strength ceramic substrate can be obtained.

The particle size and specific surface area of the ceramic powder used in the above are selected in consideration of the thickness of the green sheet to be produced and the shrinkage ratio after firing. In the case of powder, the particle size is 0.05 to 4 μm. , Specific surface area is 5 ~ 20m
It is preferable to select one in the range of ² / g. A more preferable range is 0.5 to 2 μm. If it is too fine, the shrinkage factor after firing becomes large and a highly accurate green sheet cannot be obtained. When the specific surface area is within this range, the moldability of the green sheet is good and the shrinkage rate after firing is small, which is preferable.

The slurry for the green sheet of the present invention is
The methacrylate copolymer is butyl methacrylate,
80% by weight or more of a methacrylate unit selected from a methacrylate having an alkyl side chain at the β-position, having 8 or more carbon atoms, a hydroxyl group-containing methacrylate and a cycloalkyl group-containing methacrylate, and the content of the butyl methacrylate unit is 50% by weight. % Or more of the methacrylate-based copolymer is dissolved in a solvent as a binder, and the ceramic powder is dispersed in the solution to produce the copolymer. As the solvent, a water-soluble or organic solvent can be used. Depending on the binder, an organic solvent may be added to the water-soluble solution. Any organic solvent may be used as long as it can dissolve the binder and the plasticizer. For example, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, γ-butyrolactone, toluene, etc. The containing organic solvent mixture is used.

The composition of the slurry for forming the green sheet of the present invention is preferably selected within the following range. (A) Ceramic powder; 70 to 96% by weight (b) Methacrylate-based copolymer; 30 to 4% by weight (c) Solvent; 30 to the total of the above ceramic powder and methacrylate-based copolymer component
80% by weight.

In addition to the above, if necessary, a plasticizer, a dispersant,
An anti-sedimentation agent, a sintering aid, etc. may be contained. More preferably in the above, the composition of the ceramic powder and the methacrylate copolymer is 75 to 85% by weight and 25 to 1% by weight, respectively.
It is preferable to select in the range of 5% by weight. If the content of the methacrylate copolymer component exceeds 30% by weight, warpage during firing, waviness and cracks will occur, and circuits will tend to shift when the green sheets are laminated, and binder removal during firing will be difficult. On the other hand, if it is less than 4% by weight, the binding force as a binder is weakened, the green sheet moldability is deteriorated, and cracks and cracks are likely to occur. Also, the solvent is 80
If it exceeds 5% by weight, the viscosity of the slurry is low and molding on a polyester film becomes difficult, and it takes time to dry. If it is less than 30% by weight, the slurry viscosity is high and molding becomes difficult.

The mixture having the above composition is pulverized and mixed with a ball mill or an attritor for, for example, 20 to 48 hours to prepare a slurry. In addition, the above solvent is added as necessary to adjust the viscosity of the slurry. Furthermore, as a plasticizer, dibutyl phthalate, dioctyl phthalate, polyethylene glycol, glycerin or the like can be added as a dispersant, and sorbitan ester, alkylene glycol, polycarboxylic acid or the like can be added, if necessary. The slurry thus obtained is continuously formed into a thickness of 0.01 mm to 0.5 mm on a polymer film such as polyester using a doctor blade. 80-1
It is heated at a temperature of 20 ° C. to evaporate the solvents and form a ceramic green sheet.

The thickness of the ceramic green sheet of the present invention is in the range of 0.01 to 0.5 mm, preferably 0.05 to 0.2 mm. If the thickness exceeds 0.5 mm, the substrate becomes thick when the green sheets are laminated to form a multilayer wiring board, while if the thickness is less than 0.01 mm, handling problems occur, which is not preferable. The ceramics green sheet thus obtained varies depending on the powder used, the type and content of the methacrylate copolymer or plasticizer as a binder, the content of which is 5 to 50 k.
It has a tensile strength of g / cm ² and can withstand handling.

Subsequently, the obtained ceramic green sheet is filled with a conductive paste such as tungsten, molybdenum, copper, silver, silver-palladium, or gold in the via hole portion by printing, squeegee, a dispenser, or a roller embedding method. Filling is performed to form conductors for connecting wiring layers in the via holes. By using the resin binder of the present invention, it is possible to easily remove the binder during firing of the conductor and in a short time, and therefore a conductor mainly containing copper, tungsten or molybdenum can be preferably used.

If necessary, a predetermined conductor, insulator or resistor pattern is printed on the surface of the sheet. Also, a guide hole is drilled in the same manner as forming a via hole. Next, the required number of sheets are stacked using the guide holes, and at a temperature of 90 to 130 ° C., 50 to 200 kg / cm ²
The sheets are bonded together under pressure to produce a sheet made of a multilayer substrate.
The firing atmosphere of the ceramics green sheet differs depending on the type of conductor, but in the case of metals such as copper, nickel, tungsten and molybdenum, the binder is decomposed and evaporated in an inert atmosphere containing water vapor. Next, it can be fired in an atmosphere containing oxygen in the range of 3 to 100 ppm and the balance being neutral gas such as nitrogen or argon or controlled by steam.

In particular, the firing is preferably carried out at a temperature of 300 to 500 ° C. for evaporating the organic binder and holding it for 30 minutes to several hours to decompose and evaporate the binder. Especially in the case of a ceramic multilayer substrate for low temperature firing, the sintering temperature is preferably 800 to 1000 ° C. Thus, a fired ceramic multilayer substrate is obtained. The amount of carbon remaining in the multilayer substrate after firing the ceramic green sheet should be 250 ppm or less. Otherwise, the strength of the substrate after firing will decrease, the porosity will increase, the dielectric constant will increase, and the dielectric loss (tan
Problems such as an increase in δ) or a decrease in insulation resistance occur, making it unusable as a multilayer substrate. The amount of residual carbon is 1
It is preferably at most 00 ppm, more preferably at most 50 ppm.

In the present invention, when the green sheets are laminated to form a multilayer, the number of layers is typically 4 to 50, but the preferred number of layers is 5 to 15. Within this range, the binder can be decomposed and evaporated in a short time, and the residual carbon amount is 50 p.
It becomes pm or less. Although the decomposition mechanism of the methacrylate copolymer of the present invention is not clear, since the methacrylate copolymer does not have hydrogen at the α-position of the methylene group skeleton of the methacrylate unit, the C—C main chain is cleaved by heat and the monomer unit It is expected that the methacrylate-based copolymer will be decomposed due to gasification and scattering of this monomer unit after being decomposed into.

When the methacrylate-based copolymer binder of the present invention is used, decomposition of the binder begins to occur at a low temperature of about 300 ° C. and is almost completed at a temperature of 500 ° C., so that a green sheet made of a glass-ceramic composition is used. In some cases, it is convenient because the binder decomposes and evaporates at a temperature below 600 ° C. at which glass sintering begins.

[0042]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited by the following examples, and the present invention is modified and implemented in accordance with the spirit of the description. All embodiments are included in the invention.

[0043]

[Reference example] In the following reference examples, all concentrations and compositions are wt%.
Express with. The molecular weight was measured as follows. Measuring device: WATERS gel permeation chromatography "M-410" Detector: Differential refractometer Column used: WATERS ultrastyra gel (7.8 mmφ x 300 mmL) x 4 Standard substance: polystyrene Measuring conditions: Flow rate 1 cc / min (THF) Temperature 40 ° C

<Binder Synthesis> Reference Example 1 80 parts by weight of toluene as a solvent was placed in a separable flask equipped with a stirrer, a thermometer, a nitrogen introducing tube, a monomer dropping funnel and a polymerization initiator dropping funnel, and nitrogen was introduced from the nitrogen introducing tube. Is blown into the flask to replace it with nitrogen. Isobutyl methacrylate 90 is used for the monomer dropping funnel.
100 parts by weight of a monomer mixture consisting of 9 parts by weight of n-butyl methacrylate and 1 part by weight of methacrylic acid,
A solution prepared by dissolving 1.8 parts by weight of azobisisobutyronitrile in 30 parts by weight of toluene is charged in the dropping funnel of the polymerization initiator. Then, the flask was heated to 60 ° C., the monomer and the polymerization initiator were added dropwise over 2 hours with stirring at the same temperature, and the mixture was stirred at the same temperature for 2 hours, and then the internal temperature was raised to 80 ° C. Then, the mixture was further heated and stirred for 2 hours and then cooled and cooled to obtain a methacrylate copolymer (I). The molecular weight distribution of the obtained copolymer (I) was measured by the above-mentioned method to determine the number average molecular weight, and the glass transition temperature (T
g) and the acid value were determined, and a predetermined amount of the copolymer (I) was put into a platinum crucible, the temperature was raised to 600 ° C. in a nitrogen stream, and the amount of residual carbide was measured when the temperature was maintained at the same temperature for 2 hours.
As a result, the content rate of the molecular weight of 1,000 to 1,000,000 is 91.
%, The molecular weight was 1000 to 150,000 / 150,000 to 1,000,000 (weight ratio), 3/1, the number average molecular weight was 20,000, Tg was 46 ° C., and the amount of residual carbide was 70 ppm.

Reference Example 2 40 parts by weight of isobutyl methacrylate as a monomer, n-
A methacrylate copolymer (V) was obtained in the same manner as in Reference Example 1 except that the composition was 40 parts by weight of butyl methacrylate, 17.5 parts by weight of 2-ethylhexyl methacrylate, and 2.5 parts by weight of methacrylic acid. The result of measurement in the same manner as in Reference Example 1 shows that the content of the polymer having a molecular weight of 1,000 to 1,000,000 is 94%, the molecular weight of 1,000 to 150,000 / 150,000 to 1,000,000 (weight ratio) is 5/1, and the number average molecular weight is 45,000. Tg27
The residual carbide content was 90 ppm at 90 ° C.

Reference Examples 3 to 8 Methacrylate type copolymer (II) to
(IV) and (VI) to (VIII) were obtained. All monomer composition concentrations are expressed in weight percent. A. Binder The following methacrylate-based copolymer was used as a binder. Methacrylate Copolymer (I) Methacrylate Component; Isobutyl Methacrylate 90% n-Butyl Methacrylate 9% Vinyl Polymer Component; Methacrylic Acid 1% Methacrylate Copolymer (II) Methacrylate Component; Isobutyl Methacrylate 81% n-Butyl Methacrylate 9% 2-Hydroxyethyl Methacrylate 9% Vinyl Polymer Component; Methacrylic Acid 1% Methacrylate Copolymer (III) Methacrylate Component; Isobutyl Methacrylate 81% n-Butyl Methacrylate 9% 2-Hydroxypropyl Methacrylate 9% Vinyl Polymer Component; Methacrylic Acid 1 % Methacrylate copolymer (IV) methacrylate component; isobutyl methacrylate 81% n-butyl methacrylate 9% cyclohexyl methacrylate 9% vinyl polymer component; methacrylic acid 1% methacrylate copolymer (V) methacrylate component; isobutyl methacrylate 40% n-butyl methacrylate 40% 2-ethylhexyl methacrylate 17.5% vinyl polymer component; methacrylic acid 2.5% methacrylate Copolymer (VI) methacrylate component; isobutyl methacrylate 40% n-butyl methacrylate 40% 2-hydroxyethyl methacrylate 17.5% vinyl polymer component; methacrylic acid 2.5% methacrylate copolymer (VII) methacrylate component; Isobutyl Methacrylate 40% n-Butyl Methacrylate 40% 2-Hydroxypropyl Methacrylate 17.5% Vinyl Polymer Component; Methacrylic Acid 2.5% Methacrylate Copolymer ( III) methacrylate component; isobutyl methacrylate 40% 40% n-butyl methacrylate polymer component; methacrylate 2.5 alpha-methylstyrene 17.5%

B. Solvent A mixed solvent of toluene and methyl ethyl ketone C.I. Plasticizer Dioctyl phthalate E. Ceramics component Alumina powder Average particle size 0.8 μm Cordierite powder Average particle size 1.0 μm In glass-ceramics powder, alumina (inorganic filler) powder is 50%, glass powder is 50%, glass composition is SiO ₂ ; 60, CaO; 15 , Al ₂ O ₃ ; 1
3, MgO; 5, B ₂ O ₃ ; 4, TiO ₂ ;
The glass powder was finely pulverized in advance with an attritor, and the powder having an average particle diameter of 2.2 μm and a specific surface area of 5.0 m ² / g was used. In the glass-ceramic powder, the ceramic (inorganic filler) powder is 50% and the mullite powder is 25%.
%, Spinel 5%, silica 20%. Glass powder is 50%, glass composition is SiO ₂ ; 54, CaO; 2
0, Al ₂ O ₃ ; 13, MgO; 2, B ₂ O ₃ ; 8, T
iO _2; 3. The glass powder was finely pulverized in advance with an attritor, and the average particle diameter of the powder was 1.5 μm and the specific surface area was 5.2.
m ² / g was used.

[0048]

【Example】

Examples 1 to 12 <Production of green sheet> A. Preparation of Slurry 15% of the above methacrylate powders (I) to (VIII) as a binder to 85% of the above ceramic powder, and toluene / methyl ethyl ketone (1 / 1) 40% mixed solvent and dioctyl phthalate as a plasticizer were mixed with an attritor to prepare a slurry.
The prepared composition is shown in Table 1. B. Preparation of green sheet Molding was performed by the doctor blade method. The film thickness of the obtained green sheets (A to L) is shown in Table 1. <Manufacture of Multilayer Substrate> C.I. Printing and stacking The obtained green sheets (A to L) were processed into 2000 holes having a via hole diameter of 200 μm by punch brace using a mold. And for B, C, E and F by screen printing, a thick film paste of copper (viscosity 10,000 to 20,000 cp),
With respect to A, D, and G to L, a thick film paste of tungsten (viscosity of 10,000 to 20,000 cp) is embedded to form a conductor for interlayer connection of wiring. A predetermined circuit pattern is printed on the surface of the green sheet by using a film thickness paste having the same metal composition as the above but having a viscosity adjusted to a low level (5,000 to 15,000 cp). Stack six green sheets printed with copper or tungsten using the guide holes, 120
By thermocompression bonding at 150 ° C. and a pressure of 150 kg / cm ^2, a multilayer ceramic green sheet consisting of 6 layers was produced. D. Debinding The obtained multi-layered ceramic green sheet consisting of 6 layers was debindered by raising the temperature to 550 ° C. at 300 ° C./hour in a nitrogen gas stream containing 3 to 5 ppm of oxygen and holding at the same temperature for 2 hours. . E. Sintering Debinding the green sheets A, D, G to L is 16
At 500 ° C., the green sheets B and E were kept at 1000 ° C., and the green sheets C and F were kept at 900 ° C. for 0.5 hours to sinter, respectively, to obtain a ceramic multilayer substrate. Similarly, a green sheet with no printed circuit pattern was similarly laminated, debindered, and sintered to obtain a sintered substrate, the characteristics of which are shown in Table 1.

Examples 13 and 14 Cordierite powders and glass-ceramics powders of the above-mentioned ceramics powders, and methacrylate-based copolymer (I) as a binder were used in Examples 1 to 1.
A green sheet was produced under the same conditions as 12. Unlike the above-mentioned embodiment, the conductor was printed with a predetermined circuit by using a thick film paste of silver-palladium alloy instead of copper. The obtained 10 green sheets were stacked using the guide holes and thermocompression bonded at 120 ° C. and a pressure of 150 kg / cm ² to obtain a multilayer ceramic green sheet consisting of 10 layers. The obtained 10-layer multilayer ceramic green sheet was heated in the atmosphere at 500 ° C./hour to remove the binder, and held at the same temperature for 1 hour to remove the binder. Further, the temperature is raised at the same rate to 1000 ° C and 900 ° C, respectively.
Sintering in 15 minutes gave a ceramic multilayer substrate. Similarly, a green sheet on which no circuit pattern was printed was similarly laminated, an escape binder, and sintered to obtain a sintered substrate, the characteristics of which are shown in Table 1.

[0050]

[Comparative example]

Comparative Examples 1 to 3 A green sheet was prepared under the same conditions as in Example 1 except that a polymethylmethacrylate resin was used as the binder instead of the methacrylate copolymer as the binder, and debinding and sintering were performed. A ceramic substrate was obtained. Since the prepared ceramic multilayer substrate is insufficient in debinding, the residual carbon amount is 200
It was 0, 2400, 3100 ppm. Further, the bending strength and the insulation resistance were low, and they could not be used as a multilayer substrate. The characteristics of the sintered substrate are shown in Table 2.

Comparative Example 4 Green sheets were prepared under the same conditions as in Examples 13 to 14 except that cordierite powder among the above ceramic powders and polymethylmethacrylate resin was used as the binder instead of the methacrylate copolymer. did. A predetermined circuit was formed by a thick film paste of silver-palladium alloy by the screen printing method. The obtained 10 green sheets are stacked by using the guide holes, and the temperature is 120 ° C., 150
Thermocompression bonding was performed under a pressure of kg / cm ² to obtain a multilayer ceramic green sheet consisting of 10 layers. The obtained 10-layer ceramics green sheet was debindered by raising the temperature at 500 ° C./hour in the atmosphere and holding it at the same temperature for 1 hour.
Sintering was carried out at 00 ° C. for 15 minutes to obtain a ceramic multilayer substrate.
Since the prepared ceramic substrate is insufficient in debinding, the residual carbon amount is 300 ppm, especially 1000 pp inside.
It was m.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

EFFECTS OF THE INVENTION The ceramic green sheet of the present invention is configured as described above, and is excellent in strength and handleability, as well as debinding in an oxidizing atmosphere,
It has the property that even when heated in a non-oxidizing atmosphere, the binder is easily decomposed and scattered without carbonization.
In addition, the ceramic sheet after sintering does not have a warp or a bend in appearance, does not have a black gray appearance in which carbides remain, the residual carbon amount is 250 ppm or less, and the volume resistivity value is 10 ¹³ Ωcm. It is above, and it has sufficient insulation.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akiko Yoshimura 1-1-1, Sonoyama, Otsu City, Shiga Toray Co., Ltd. Shiga Plant (72) Inventor Shigemi Osaka, 992, Nishioki, Nishihama, Aboshi-ku, Himeji-shi, Hyogo 1 Japan Catalysts and Catalysts Research Institute Co., Ltd. (72) Inventor Kazuo Hata at 992 Nishikioki, Akihama, Aboshi Ward, Himeji City, Hyogo Prefecture 1 1 Japan Catalysts and Catalysts Research Institute Co., Ltd. (72) Noriichi Aikawa 992 Okihama Nishioki, Aboshi Ward, Himeji City, Hyogo Prefecture No. 1 Inside Japan Catalyst Catalyst Research Institute

Claims (4)

[Claims] 1. 80% by weight or more of a methacrylate unit selected from the group consisting of ceramic powder and butyl methacrylate, a C 8 or more methacrylate having an alkyl side chain at the β-position, a hydroxyl group-containing methacrylate and a cycloalkyl group-containing methacrylate. And the content of the butyl methacrylate unit is 50% by weight.
A ceramics green sheet containing the above-mentioned methacrylate-based copolymer. 2. The ceramics according to claim 1, wherein the methacrylate copolymer is a methacrylate copolymer containing a monomer unit selected from unsaturated carboxylic acids, acrylates and styrenes.
Green sheet. 3. The ceramic powder contains at least one selected from the group consisting of alumina, zirconia, magnesia, beryllia, mullite, cordierite, spinel, forsterite, anorthite, cergian, clinoenstatite and silica. The ceramic green sheet described in 1 or 2. Wherein SiO ₂ 30 to 70 wt% ceramic powder in terms of oxide title _Al 2 _O 3 6 to 25 wt% CaO 5 to 25 wt% MgO 1 to 10 wt% _B 2 _O 3 3 to 50 wt% In the composition range of TiO ₂ 1 to 15% by weight, 40 to 60% by weight of glass composition powder having a total amount of 95% by weight or more, and alumina, zirconia, magnesia, beryllia, mullite, cordierite, forsterite, spinel, anorthite 60 to 40% by weight of at least one inorganic filler powder selected from the group consisting of, Cerdian, clinoenstatite and silica
4. A raw material mixture of
The ceramic green sheet according to any one of 1.