JP2003318313A - Method for manufacturing ceramic substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a ceramic substrate capable of forming a highly minute via hole of a high aspect ratio by using photolithography and having a favorable state after the via hole is formed in a following step so as to obtain sufficient characteristics in a high-frequency region. <P>SOLUTION: The method for manufacturing the ceramic substrate comprises at least one type of a developing step selected from a group composed of a spraying method and a dipping step and the developing step by an ultrasonic wave in a method for developing the ceramic substrate using the photosensitive ceramic composition of inorganic particles having a mean particle size of 420 nm or less in 30 wt.% or more of the inorganic particles of the photosensitive ceramic composition containing the inorganic particles and the photosensitive organic component. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a ceramic substrate using a photosensitive ceramic composition. The method for producing a ceramic substrate using the photosensitive ceramic composition of the present invention is a substrate for high-density mounting of semiconductor elements, which requires fine circuit pattern formation of the surface layer of the substrate surface and internal electrodes, a high-frequency wireless substrate, Especially, it is preferably used for a multilayer substrate.

[0002]

2. Description of the Related Art In recent years, in systems such as computers, miniaturization and higher performance have been advanced, and accordingly,
The spread of wireless communication technologies such as mobile phones is remarkable.
Conventional mobile phones use the quasi-microwave band of 800 MHz to 1.5 GHz, but with the increase in the amount of information, there is a wireless technology in which the carrier frequency is changed from the higher frequency microwave band to the millimeter wave band. The situation is being proposed and realized. Such high-frequency wireless circuits are expected to be applied to mobile communication and network equipment, and among them, Bluetooth (Bluetooth) and ITS (Intelligent Transport) are expected.
System, advanced traffic information system) is becoming an increasingly important technology.

In order to realize these high frequency circuits,
The substrate material used therefor must also have excellent high-frequency transmission characteristics in the frequency band, that is, 1 to 100 GHz. In order to achieve excellent high frequency transmission characteristics,
It is necessary to have low dielectric constant and low dielectric loss, high processing accuracy, and good dimensional stability. Among them, ceramic substrates have been regarded as promising.

Conventional ceramics substrate materials are excellent in dimensional stability, but have a low degree of fine processing. Therefore, sufficient characteristics cannot be obtained particularly in a high frequency region. As a method for improving the problem of such fine processing precision, Japanese Patent Laid-Open No. 6-202323 discloses
A method of forming via holes by a photolithography technique using a green sheet formed of a photosensitive ceramic composition has been proposed. However, since the photosensitive ceramic composition has low sensitivity and resolution, it has a drawback that via holes of 100 μm or less cannot be formed accurately and uniformly on a sheet having a high aspect ratio, for example, a sheet having a thickness exceeding 50 μm. .

[0005]

As a method for improving these problems, in JP-A-10-171106 and JP-A-10-265270, scattering of exposure light,
Focusing on reflection, to improve light transmission and straightness,
A method of matching the refractive index of the organic component and the inorganic component has been proposed. However, for a sheet having a thickness exceeding 100 μm, for example, there is a drawback that a via hole having a thickness of 100 μm or less cannot be formed accurately and uniformly and a residue remains. there were.

It is indispensable to increase the degree of fine processing of a ceramic substrate material having excellent dimensional stability and a low dielectric loss tangent so that via holes can be formed accurately and uniformly. For that purpose, it is essential that the ceramic composition and the processing method such as via hole formation are in an appropriate state.

[0007]

That is, the present invention is a photosensitive ceramic composition containing inorganic particles and a photosensitive organic component, and 30% by weight or more of the inorganic particles have an average particle size of 420.
A method for developing a ceramic substrate using a photosensitive ceramic composition which is an inorganic particle having a particle size of not more than nm, characterized by having at least one kind of developing step selected from a spray method and a dipping method and a developing step by ultrasonic wave. And a method of manufacturing a ceramic substrate.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, in the step of forming a via hole of a photosensitive ceramic sheet, a high aspect ratio is obtained by combining at least one kind of developing step selected from a spray method and a dipping method with an ultrasonic developing step. It is possible to obtain a ceramic substrate having a high-precision via hole with a specific ratio.

The dipping method in the present invention is a developing method in which an unexposed portion is dipped in a developing solution to promote a dissolution reaction. As the dipping form, the developing substrate may be placed flat and dipping, but it is preferable to dip the developing substrate in a substantially vertical state in the developing solution bath from the viewpoint of work efficiency and quality control. Further, during the immersion, the developing substrate may be moved by vibrating, rotating, reciprocating, or the like. Alternatively, the developer may be circulated or vibrated.

The spray method in the present invention is a developing method in which the unexposed portion is removed by the physical force of the spray to promote the dissolution reaction. Therefore, it has the advantage of shortening the development time, and is therefore preferable to the dipping method. Further, since a new developing solution is constantly flowing out, the dissolving power of the developing solution does not decrease, which is preferable.

Although not particularly limited, in the spray developing method, the liquid supply performance of the spray per developing substrate area is preferably 0.5 to ²⁰ kg / cm ² , more preferably 1 to 10 kg / cm ^2. , And more preferably 1
~ 5 kg / cm ² . If it is less than the lower limit of the above numerical range, the physical force is insufficient and the developing time becomes long, which is not preferable. On the other hand, if it exceeds the upper limit, the hardened portion is eroded and a fine via hole pattern is not formed. By relatively moving the spray disperser and the developing substrate, the developing solution having a large area can be effectively spray-sprayed with a small disperser, and the developing solution can be dispersed at a specific position on the developing substrate. It is preferable that concentration is suppressed.

In the present invention, these spray methods,
After development using at least one type of development process selected from the dipping method, a residual film portion due to uneven development and a semi-cured portion due to light scattering are removed using ultrasonic waves to form a via hole with a high aspect ratio. Is possible.

The ultrasonic developing method in the present invention is a method of removing an unexposed portion by ultrasonic waves. The developing solution erodes the unexposed portion by the physical force of the ultrasonic waves, and the dissolution reaction proceeds while removing the developing solution. . Further, the developing solution also erodes the semi-cured portion where the exposure is insufficient, and the dissolution reaction proceeds, so that a fine via hole pattern can be formed. Basically, ultrasonic waves are applied while the substrate is immersed in the developing solution in the same manner as in the immersion method. In this ultrasonic development method, the ultrasonic frequency is preferably 2 although not particularly limited.
It is 0 to 50 KHz. If it is less than the lower limit of the above numerical range, the developer is not sufficiently dipped in the unexposed portion, which is not preferable, while if it exceeds the upper limit, the developer corrodes the cured portion, which is not preferable. The power density of ultrasonic waves per substrate area is preferably 40 to 100 W / cm ² . If it is less than the lower limit of the above numerical range, the unexposed portion cannot be removed completely, which is preferable. On the other hand, if it exceeds the upper limit, the hardened portion is eroded and a fine via hole pattern is not formed. The ultrasonic development time is preferably 5 to 120 seconds, more preferably 5 to 60 seconds, still more preferably 10 to 30 seconds.
If it is less than the lower limit of the above numerical range, the unexposed portion cannot be completely removed, and if it exceeds the upper limit, the hardened portion is eroded and a fine via hole pattern is not formed, which is not preferable.

The shape of the via hole pattern is expressed by the following equations (1) to (3) and has a maximum pattern width ratio P _b ,
It is represented by the minimum pattern width ratio P _s and the pattern depth ratio P _d .

P _b = r ₂ / r ₀ (1) P _s = r ₁ / r ₀ (2) P _d = d ₁ / d ₀ (3) (however, the hole width on the film surface of the via hole pattern (of the mask Pattern diameter) r ₀ , the hole width of the narrowest part is r ₁ , the hole width of the widest part is r ₂ , the thickness of the green sheet is d ₀ , and the depth of the via hole is d ₁ . In the present invention, a fine via hole pattern means P _b <1.
2, P _s > 0.9 and P _d = 1.

The photosensitive ceramic composition of the present invention contains inorganic particles and a photosensitive organic component as essential components. The inorganic particles are commonly used powders of glass and metals (gold, platinum, silver, copper, nickel, aluminum, palladium, tungsten, ruthenium oxide, etc.).

The shape of the inorganic powder used in this case is spherical,
It may be elliptical, flat, rod-shaped or fibrous, but if a spherical one is used, the increase in viscosity when dispersed in a resin solution is small and the fluidity is excellent,
Further, since it is possible to form a high-definition via hole with a high aspect ratio, it is preferable to use inorganic particles having a sphericity of 80 number% or more. The sphericity may be measured as follows. First, the powder to be measured is photographed with an optical microscope at a magnification of 300 times and counted. Then, the value obtained by calculating the ratio of the number of spheres (minor axis / major axis ≧ 0.8) is defined as the sphere rate. However, since it is often difficult to determine that the photographed image is three-dimensionally spherical, the photographed image that is a plane image has a circular shape (minor axis /
The circularity, which is a value obtained by calculating the ratio of the number of major diameters ≧ 0.8), may be used as the sphericity.

When a powder having a wavelength of light of 350 to 420 nm, which is used for pattern formation such as an ultra-high pressure mercury lamp, is used, the light at the time of exposure is not scattered and the exposure characteristics are not damaged. In the present invention, the content of the inorganic particles of 420 nm or less, which is finer than the wavelength of light, is 30% by weight or more, preferably 40% by weight or more, more preferably 50% by weight or more. By including 30% by weight or more of the inorganic particles having such a particle size and its distribution, the powder filling rate is improved, and even if the particle ratio in the green sheet is increased, bubbles are less likely to be involved. Further, since the excess light scattering is small, the pattern formability is enhanced. If it is less than 30% by weight, the filling rate of the particles decreases and the distance between the particles increases, so that it becomes difficult to maintain sufficient strength against the erosion force of the developing solution by ultrasonic waves.

In the present invention, the inorganic particles preferably have an average particle size of 0.1 μm or less, and more preferably spherical inorganic particles having an average particle size of 0.005 to 0.1 μm. The larger the filling amount of spherical and fine inorganic particles, the higher the packing density, the less entrainment of bubbles, and the green sheet in which the inorganic particles are densely dispersed can be obtained. The distance between particles becomes small, and it becomes possible to maintain sufficient strength against the erosion force of the developing solution by ultrasonic waves, and it is possible to selectively dissolve only the unexposed portion of the photosensitive organic component between the inorganic particles. It will be possible.

The combination of the developing methods used in the present invention is a method for improving the pattern shape of the pattern processing by the photolithography method, and the composition for forming a circuit board is not limited to the ceramic composition. It is also applicable to non-fired organic-inorganic hybrid compositions.

The ceramic powder suitable for the inorganic particles in the present invention is selected from the group consisting of alumina, zirconia, magnesia, beryllia, mullite, cordierite, spinel, forsterite, anorthite, cergian, silica and aluminum nitride. At least one. Particularly preferred are silica, alumina, titania and the like, but it is also possible to use a mixture of a plurality of types of components.

When the inorganic particles in the present invention are composite particles of glass and ceramics, the glass particles are preferably used in an amount of 30% by weight or more, more preferably 50% by weight or more. If the glass powder has a spherical shape, the packing density is high, a dense sintered body can be obtained, and the surface area is small, so that light scattering during exposure can be reduced. Average refractive index 1.5 to 1.65
It is desirable to use some glass powder. In addition, the inorganic particles contained in the present invention are sintered in the firing step, and when the substrate is formed for the purpose of the present invention, 1000
So-called low-temperature-calcined inorganic powder is desirable because it is preferable to calcinate at a temperature of not higher than 70 ° C., especially at a temperature of 700 to 900 ° C. Of course, since these inorganic particles determine the basic physical properties such as electric characteristics, strength, and thermal expansion coefficient of the substrate, they are selected according to the desired characteristics.

The inorganic particles have a refractive index of 1.5 to
1.8 is preferable. When the average refractive index of the organic component is significantly different from the average refractive index of the inorganic particles, reflection and scattering at the interface between the inorganic particles and the photosensitive organic component become large, and a fine pattern cannot be obtained. By matching the refractive indexes of the inorganic powder and the organic component, reflection / scattering at the interface between the inorganic particles and the photosensitive organic component is reduced, and a high-precision via hole with a high aspect ratio can be obtained.

The photosensitive organic component used in the present invention preferably contains a polymer having a carboxyl group in its side chain, and more preferably contains an acrylic copolymer having a carboxyl group in its side chain. The polymer having a carboxyl group in the side chain enables development with an alkaline aqueous solution in the developing step after pattern exposure, and this polymer is excellent in that thermal decomposition in the baking step proceeds at a relatively low temperature. ing. It is also preferable to use a copolymer to improve the physical properties of the polymer in order to control various properties of the composition of the present invention. A photoreactive compound and a photopolymerization initiator are further added to the photosensitive organic component.
If necessary, an additive component such as a binder polymer, a sensitizer, an ultraviolet absorber, a dispersant, a surfactant, an organic dye, a plasticizer, a thickener, an antioxidant and an antigelling agent may be added. it can.

Examples of the polymer having a carboxyl group in the side chain include acrylic acid, methacrylic acid, itaconic acid,
A carboxyl group-containing unsaturated monomer such as crotonic acid, maleic acid, fumaric acid, vinyl acetic acid or their acid anhydrides and monomers such as methacrylic acid esters, acrylic acid esters and 2-hydroxyethyl acrylate are selected and appropriately selected. It can be obtained by copolymerizing with a radical polymerization initiator, but is not limited thereto. It is also possible to add another polymerizable monomer having an unsaturated group as a copolymerization component.

Further, it is also preferable that the copolymer having a carboxyl group in the side chain has an ethylenically unsaturated group in the side chain. Examples of the ethylenically unsaturated group include a vinyl group, an allyl group and an acryloyl group. Examples thereof include methacryloyl group. Such a method of adding an ethylenically unsaturated group side chain to a polymer is an ethylenic group having a glycidyl group or an isocyanate group with respect to a mercapto group which is an active hydrogen-containing group in the polymer, an amino group, a hydroxyl group or a carboxyl group. An unsaturated compound, acrylic acid chloride, methacrylic acid chloride or allyl chloride is subjected to an addition reaction. Examples of the ethylenically unsaturated compound having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, glycidyl ethyl acrylate, glycidyl crotonic acid, and glycidyl isocrotonic acid. Examples of the ethylenically unsaturated compound having an isocyanate group include (meth) acryloyl isocyanate (the above-mentioned "(meth) acryloyl" means "acryloyl and / or methacryloyl", the same applies to others), (meth) acryloylethyl isocyanate, etc. There is. Further, the ethylenically unsaturated compound having a glycidyl group or an isocyanate group, acrylic acid chloride, methacrylic acid chloride or allyl chloride is 0.05 to 0.95 with respect to the mercapto group, amino group, hydroxyl group or carboxyl group in the polymer. It is preferable to add a molar equivalent. When the active hydrogen-containing group is a mercapto group, an amino group, or a hydroxyl group, the entire amount thereof can be used for the introduction of a side chain group, but in the case of a carboxyl group, the acid value of the polymer is kept within a preferable range. It is preferable to add in the range of.

In the present invention, the photosensitive organic component contains a photoreactive compound, and the crosslinking reaction and the polymerization reaction by the photoreaction of these photoreactive compounds play a functional role. The photoreactive compound having such a role is a compound having an active carbon-carbon double bond, which is a monofunctional or polyfunctional compound having a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, an acrylamide group or the like as a functional group. At least one selected from the functional compounds is used. Since the photoreactive compound may affect the mixing / dispersing properties of the inorganic fine particles, it is appropriately selected according to the characteristics. The photoreactive compound is not limited to one type, and it is possible to use a mixture of a plurality of types, in which case the stable dispersibility of the inorganic particles is maintained and the photoreactive compound is formed from the composition of the present invention. It is preferable to select the green sheet by taking into consideration the shape stability and pattern formability of the green sheet. Although not limited thereto, it is preferable to contain a urethane compound having an ethylenically unsaturated group.

The urethane compound is not particularly limited as long as it has a urethane bond (-NHCOO-). The organic group which the urethane compound has, in addition to urethane bond, vinyl group, allyl group, acryloyl group, methacryloyl group, alkylene group, alkylene oxide group, alkyl group, aryl group, arylene group, aralkyl group, aralkylene group, hydroxyalkyl group. , And a hydroxyalkylene group can be exemplified. Among these, polar groups such as alkylene oxides are preferable from the viewpoint of compatibility. Further, as the ethylenically unsaturated group, it is generally preferable that the steric hindrance is small and the degree of freedom of molecular motion is large in consideration of the crosslinking reactivity, that is, the ethylenically unsaturated group has many large substituents. Not preferable. Therefore, mono-substitution and then di-substitution are preferable, but the cross-linking reactivity may be improved rather depending on the chemical characteristics of the substituent. Specifically, for example, vinyl group, allyl group, acryloyl group, methacryloyl group and the like can be mentioned. In particular, it is preferable to have an acryloyl group or a methacryloyl group, but it is not particularly limited thereto.

Since the photosensitive organic component having an unsaturated group as described above generally has a low ability to absorb the energy of actinic rays, a photopolymerization initiator may be added in order to initiate the photoreaction. preferable. In some cases, a sensitizer may be used to maintain the effect of the photopolymerization initiator. Such photopolymerization initiators include mechanistic direct cleavage agents, ion-transfer electron transfer type, hydrogen abstraction type, two-molecule complex type and the like, which are mechanically different, and are selected from them.
The photopolymerization initiator used in the present invention preferably generates an active radical species. The photopolymerization initiator and the sensitizer may be used alone or in combination of two or more. The photopolymerization initiator is preferably added in an amount of 0.05 to 10% by weight, more preferably 0.1 to 10% by weight, based on the photosensitive organic component.
Is. By setting the addition amount of the photopolymerization initiator within this range, good photosensitivity can be obtained while maintaining the remaining portion of the exposed portion.

The photosensitive ceramic composition of the present invention is formed as a green sheet or a coating film through a state referred to as a slurry or paste, and the photosensitive function of the composition is utilized for high-precision processing (via hole formation). Etc.), and then subjected to non-shrinkage firing and provided as a substrate material or the like for each use. The green sheet is a sheet-like material used to make a multilayer ceramic substrate.
Conductive paste and insulating paste are alternately printed and laminated on this sheet to form a multilayer, and a green sheet printing method that completes firing in one step, or a green sheet lamination in which a conductor is printed and thermocompression-bonded and then fired to form a multilayer It is used in the law. The coating film is a film formed by coating on a functional material such as a substrate.

As described above, the green sheet or the coating film is formed from the slurry or paste. In this step, the volatile components such as the solvent contained in the slurry or paste are evaporated and dried. The photosensitive ceramic composition in the state of a green sheet or a coating film obtained through this step has a form in which an inorganic powder and inorganic fine particles are dispersed in a continuous medium in which an organic photosensitive component is formed. It has become. Further, when performing pattern formation such as via hole formation on the photosensitive ceramic composition of the present invention by a photolithography technique, it is preferable that the refractive indexes of the respective components of the composition are approximate and matched. Becomes

When firing a green sheet formed of a photosensitive ceramic composition, a non-sinterable ceramic sheet may be laminated on the upper surface and the lower surface of the green sheet and fired. As a result, it is possible to shrink only in the thickness direction so that there is almost no shrinkage on the XY plane.
The firing shrinkage in the XY plane direction is preferably 1% or less, more preferably 0.5% or less, still 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 often contains lead oxide, bismuth oxide,
It is preferable to add 1 to 5% by weight of an oxidizing agent such as zinc oxide, manganese oxide, barium oxide, calcium oxide, or strontium oxide, or an oxide powder serving as a material for improving the adhesion to the glass / ceramic green sheet. Examples of such a hardly sinterable ceramics sheet include those obtained by adding polyvinyl butyral, dioctyl phthalate, a suitable oxide, an organic solvent and the like to alumina powder and forming them into a sheet by a doctor blade method. it can.

Since there is unavoidable shrinkage depending on the components of the composition of the green sheet, the composition of the composition, and various conditions during firing, it is considered that almost no shrinkage has been achieved if the shrinkage rate can be suppressed to 1% or less. You can Such conditions are also applied to a coating film formed by screen printing or the like (a method of applying a paste of a photosensitive ceramic composition on a substrate made of ceramics or the like, and generally, the substrate is left as it is and 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 the constraint sheet placed on the upper surface of the film. .

The ratio of the blending amount of the inorganic particles to the blending amount of the photosensitive organic component in the photosensitive ceramic composition is 6: 4 to 9:
It is preferably within the range of 1. That is, the compounding amount of the photosensitive organic component is 10 to 40% by weight, further 15 to 3%.
It is preferably 5% by weight. 10 photosensitive organic components
If it is less than 10% by weight, the flexibility is reduced, and if it is more than 40% by weight, the voids of the inorganic components in the composition are filled up and the air permeability is impaired. It is preferably within the above range.

The photosensitive ceramic composition of the present invention can be prepared as follows. First, a polymer having a carboxyl group in the side chain, which is a photosensitive organic component, a photoreactive compound, and a photopolymerization initiator are mixed with a solvent and various additives as needed, and then filtered to prepare an organic vehicle. . If necessary, pretreated inorganic particles and an inorganic component consisting of a filler component are added to the mixture, and the mixture is homogeneously mixed and dispersed by a kneader such as a ball mill to prepare a slurry or paste of the photosensitive ceramic composition. The viscosity of this slurry or paste is the compounding ratio of inorganic particles and organic components,
The amount is appropriately adjusted depending on 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 when forming the slurry or paste may be any solvent that can dissolve the photosensitive organic component. For example, methyl cellosolve, ethyl cell soble, butyl cell soble, methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, γ-butyrolactone, toluene, trichloroethylene, methyl isobutyl ketone. , Isophorone, or an organic solvent mixture containing at least one of them is used. The amount of the solvent contained in the paste varies depending on the intended use,
There is no limitation as long as it is within the above-mentioned viscosity range, but for example, in the coating step, it is preferable that the paste (excluding the inorganic powder) contains 10 to 30% by weight. The solvent content is substantially zero in the developing stage.
Is preferred.

The obtained paste is treated with a doctor blade method,
Polyester etc. by general methods such as extrusion molding
Is continuously formed on the film with a thickness of 0.05 to 0.5 mm.
By shaping and removing the solvent by drying, the photosensitive ceramic
As a result, a green sheet, which is a box composition, is obtained. Via Ho
Is the green ceramic which is the photosensitive ceramic composition.
The pattern with the via hole forming pattern.
Pattern exposure through a mask
It is formed by developing with. Light source used for exposure
Is most preferably an ultra-high pressure mercury lamp, but is not necessarily limited to this
It is not something that will be done. Exposure conditions are the thickness of the green sheet
5 to 100 mW / cm, depending on ²Output super high
Exposure is performed using a pressure mercury lamp for 5 seconds to 30 minutes. Beer
For alignment when stacking sheets with the same method as hole formation
Guide holes can be formed.

It is preferable that the photosensitive organic component of the photosensitive ceramic composition of the present invention contains a polymer having a carboxyl group in its side chain because it can be easily developed with an alkaline aqueous solution. As an alkaline aqueous solution,
A metallic alkaline aqueous solution or an organic alkaline aqueous solution can be used. In particular, the cation size of the alkaline aqueous solution is 0.6.
It is preferably nm or less. When the size of the cations in the alkaline aqueous solution is 0.6 nm, the fine inorganic particles highly filled in the photosensitive ceramic composition prevent the fine inorganic particles from reacting with the carboxyl group of the side chain of the organic component, so that sufficient patterning is performed. Accuracy cannot be obtained. In addition, it is not preferable to include an organic component having a high polarity such as a urethane compound because swelling is likely to occur. As the metal alkali aqueous solution, a compound containing an alkali metal such as sodium ion, potassium ion, calcium ion, or an alkaline earth metal ion can be used. Specifically, sodium hydroxide, calcium hydroxide, sodium carbonate,
Examples thereof include potassium carbonate, calcium carbonate, lithium carbonate and the like. As the organic alkaline aqueous solution, a general amine compound can be used. Specifically, as the amine compound having a cation size of 0.6 nm or less in the alkaline aqueous solution, methylamine, n-propylamine, t-
Butylamine, monoethanolamine and the like can be mentioned. The size of cations is calculated by the following method. A molecular model is prepared using cerius2 manufactured by accelrys and the occupied volume is calculated. Assuming the molecule is spherical,
Calculate the diameter of the molecule from the occupied volume. This diameter is the size of the cation.

The concentration of the alkaline aqueous solution is usually 0.0
It is 5 to 1% by weight, and more preferably 0.1 to 0.5% by weight. If the alkali concentration is too low, the soluble portion is not completely removed, and 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, after performing development by a spray method or a dipping method, an ultrasonic developing method is used together.

Thus, the thickness before firing is 10 to 5
00 μm, the densest via hole pattern portion has a via hole diameter of 20 to 200 μm, a via hole pitch of 30 to 250
μm sheets can be produced. The present invention is characterized in that the physical properties of the sheet in this state are good, so that the yield of the subsequent process is improved.

Next, the required number of sheets on which the wiring patterns are formed are stacked using the guide holes, and the temperature is set to 80 to 150 ° C.
And a pressure of 5 to 25 MPa at a temperature of 3 to bond to produce a multilayer sheet. A constraining sheet mainly composed of an inorganic composition (eg, alumina or zirconia) that does not substantially exhibit sinter shrinkage at the sintering temperature of the green sheet was laminated on both surfaces of the green sheet laminate to prepare. By subjecting the green sheet multilayer body to a firing treatment, and then performing non-shrinkage firing to remove the constraining sheet, a target multilayer substrate can be produced. The firing is performed in a firing furnace. The firing atmosphere and temperature vary depending on the types of inorganic powder and organic components in the photosensitive ceramic composition, but firing is performed in air, nitrogen atmosphere, or hydrogen reducing atmosphere. The photosensitive ceramic composition of the present invention is fired at a temperature of 600 to 950 ° C.
The ceramic multilayer substrate thus obtained is used as a high frequency circuit substrate.

[0042]

EXAMPLES The present invention will be specifically described below with reference to examples. The concentration (%) is% by weight unless otherwise specified. The inorganic fine particle component and the organic component used in the examples are as follows.

A. Inorganic particles Glass particles I: Composition of glass particles: Al ₂ O ₃ (10.8
%), SiO ₂ (51.5%), PbO (15.6%), Ca
O (7.1%), MgO (2.86%), Na ₂ O (3%),
Properties of K ₂ O (2%), B ₂ O ₃ (5.3%) glass particles: glass transition point 565 ° C., thermal expansion coefficient 60.5 × 10 ⁻⁷ / K, dielectric constant 8.0 (1 MHZ) , Average particle diameter 2 μm Alumina particles I: average particle diameter 35 nm, alumina particles I
I: average particle diameter 350 nm, alumina particles III: average particle diameter 700 nm, alumina particles IV: average particle diameter 2 μm, alumina particles V: average particle diameter 10 μm, silica particles I: average particle diameter 40 nm, silica particles II: average particle diameter 600n
m B. Photosensitive organic component polymer I: styrene 30%, methyl methacrylate 3
It is obtained by addition-reacting 0.4 equivalent of glycidyl methacrylate to a carboxyl group of a copolymer consisting of 0% and methacrylic acid 40%, and has a weight average molecular weight of 43,
000, acid value 95.

Polymer II: Cyclomer P (ACA) 250 manufactured by Daicel Chemical Industries, Ltd. (obtained by addition reaction of 3,4-epoxycyclohexyl methacrylate with a copolymer of methacrylic acid and methyl methacrylate)
And a weight average molecular weight of 10,000 and an acid value of 75.

Photoreactive compound 1: bis (2-hydroxy-3-methacryloyloxypropyl) isopropylamine (GMPA) Photoreactive compound 2: TN-1 (manufactured by Negami Kogyo Co., Ltd., urethane prepolymer, molecular weight about 12000) ) Photoreactive compound 3: bis (4-methacryloylthiophenyl) sulfide (manufactured by Sumitomo Seika Chemicals Ltd .: high refractive monomer MPSMA) Photoreactive compound 4: Paracumylphenol EO-modified acrylate photopolymerization initiator: IC-369 (Ciba) ・ Gaiki Co., Ir
gacure-369) Light absorber: Sudan IV Solvent 1: 9: 1 mixed solvent of methyl ethyl ketone and n-butyl alcohol Solvent 2: γ-butyrolactone C.I. Preparation of Organic Vehicle The 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 photoreactive compound and a photopolymerization initiator were added and dissolved. The solution was vacuum degassed and then filtered through a 250 mesh filter to prepare an organic vehicle.

D. Paste Preparation Inorganic particles were mixed with the above organic vehicle and wet mixed with a ball mill for 20 hours to prepare a slurry or paste. The amount of the inorganic component was 70 parts by weight based on 30 parts by weight of the total of the photosensitive organic components in the organic vehicle.

E. The green sheet is formed and molded in a room shielded from ultraviolet rays with a distance between the polyester carrier film and the blade of 0.1 to 0.8 mm and a forming speed of 0.2 m / min. The doctor blade method was used. The thickness of the sheet was 100 μm.

F. Developer composition Developer 1: monoethanolamine, developer 2: n-propylamine, developer 3: sodium carbonate, developer 4: potassium carbonate, developer 5: calcium hydroxide, developer 6:
Polyethyleneimine (molecular weight: 1800), developer 7:
n-hexylamine G.I. Formation of via hole After cutting the green sheet into 100 mm square, the temperature is set to 80
It was dried at 0 ° C for 1 hour and the solvent was evaporated. Via diameter 30 to 1
Pattern exposure was performed for 1 minute under a contact condition between the sheet and the mask by using an ultrahigh pressure mercury lamp having an output of 15 to 25 mW / cm ² from the upper surface of the sheet using a chromium mask having a depth of 500 μm and a via hole pitch of 500 μm. Next, it was developed with a 0.5% by weight developing solution kept at 25 ° C. The spray pressure of the spray development was 1.5 kg / cm ² .
Further, the ultrasonic wave was developed at an ultrasonic frequency of 38 KHz.
After development, the via hole was washed with water using a spray.

H. Measurement of via hole pattern shape The cross section of the via hole pattern shape was measured using an SEM. From the SEM photograph, P _b, P _s, were calculated P _d.

I. Preparation of Restraint Sheet Used in Firing Polyvinyl butyral, dioctyl phthalate, organic solvent, etc. were added to alumina particles, zirconia particles or magnesia particles, and those prepared on the sheet by the doctor blade method were used.

J. Preparation of Multilayer Substrate 5 to 6 green sheets made of the photosensitive ceramic composition of the present invention are laminated, constraining sheets for non-shrink firing are arranged at the top and bottom, and a pressing pressure of 150 kg / cm at 80 ° C.
^It was thermocompression bonded at ² . The obtained multi-layer body is heated in air to 900
It was baked at a temperature of ° C for 30 minutes to prepare a multilayer substrate.

Example 1 As shown in Table 1, alumina particles I (49.8) were used as inorganic particles.
%) And glass particles I (50.2%) composite ceramics, polymer 1 as a photosensitive organic component, photoreactive compound 1, photopolymerization initiator 1 and a light absorber in a ratio of 70/30 A 100 μm green sheet was obtained. This green sheet was pattern-exposed, developed with a spray method using a 0.5% by weight monoethanolamine solution for 360 seconds, and then developed with ultrasonic waves for 15 seconds. For the via hole diameter of 100 μm, P _b = 1.
06, P _s = 1.00, P _d = 1.00, and a fine via hole pattern was obtained.

Examples 2 to 11 A green sheet was prepared using the photosensitive ceramic composition having the composition shown in Table 1, and a via hole was formed using a 0.5 wt% monoethanolamine solution. As for the developing method and the developing time, the method and time shown in Table 1 were used. The results are shown in Table 1. A fine via hole pattern satisfying P _b <1.2, P _s > 0.9, and P _d = 1 was obtained for a via hole diameter of 100 μm.

[0054]

[Table 1]

Examples 12 to 20 Green sheets were prepared using the photosensitive ceramics compositions having the compositions shown in Table 2, and via holes were formed using the types of developing solutions, developing methods, and developing times shown in Table 2. did. The results are shown in Table 2. Via hole diameter 100
A fine via hole pattern satisfying P _b <1.2, P _s > 0.9, and P _d = 1 with respect to μm was obtained.

[0056]

[Table 2]

Comparative Example 1 As shown in Table 3, alumina particles II (49.8) were used as the inorganic powder.
%) And glass particles I (50.2%), a polymer 1 as a photosensitive organic component, a photoreactive compound 1, and a photopolymerization initiator 1 were mixed at a ratio of 70/30, and a solvent 1 was used. A green sheet having a thickness of 100 μm was obtained from the slurry. This green sheet is pattern-exposed and then exposed to 0.
Development was carried out for 400 seconds by a spray method using a 5 wt% sodium carbonate solution. Relative hole diameter _{100μm, P b = 1.38, P} s = 0.85, P d = 0.73
Therefore, a fine via hole pattern could not be obtained.

Comparative Example 2 As shown in Table 3, alumina particles II (49.8) were used as the inorganic powder.
%) And glass particles I (50.2%), a polymer 1 as a photosensitive organic component, a photoreactive compound 1, and a photopolymerization initiator 1 were mixed at a ratio of 70/30, and a solvent 1 was used. A green sheet having a thickness of 100 μm was obtained from the slurry. This green sheet is pattern-exposed and then exposed to 0.
Development was performed for 300 seconds by an ultrasonic method using a 5 wt% n-propylamine solution. Via hole diameter 100μm
, P _b = 1.46, P _s = 0.95, P _d = 1.
00, a fine via hole pattern could not be obtained. In addition, the green sheet was cracked and the strength could not withstand the force of ultrasonic waves.

Comparative Examples 3 to 7 Green sheets were prepared using the photosensitive ceramic compositions having the compositions shown in Table 2, and via holes were formed using the types of developing solutions, developing methods and developing times shown in Table 2. . The results are shown in Table 2. Via hole diameter 100
P _b <1.2, P _s > 0.9, and P _d = 1 were not satisfied for μm.

Comparative Example 8 As shown in Table 3, alumina particles III (49.
8%) and glass particles I (50.2%) composite ceramics, polymer 1 (61.9%) as a photosensitive organic component,
Photoreactive compound 1 (31.2%), photopolymerization initiator 1
(6.1%) and a light absorber (0.8%) were mixed in a ratio of 70/30, and the thickness was 100 μm from the slurry using the solvent 1.
Got a green sheet of. This green sheet was pattern-exposed, developed with a spray method using a 0.5 wt% polyethyleneimine solution (molecular weight: 1800) for 360 seconds, and then developed with ultrasonic waves for 120 seconds. However, it could not be developed and a pattern could not be formed.

Comparative Example 9 As shown in Table 3, alumina particles III (49.
8%) and glass particles I (50.2%) composite ceramics, polymer 1 (61.9%) as a photosensitive organic component,
Photoreactive compound 1 (31.2%), photopolymerization initiator 1
(6.1%) and a light absorber (0.8%) were mixed in a ratio of 70/30, and the thickness was 100 μm from the slurry using the solvent 1.
Got a green sheet of. This green sheet was pattern-exposed and developed for 360 seconds by a spray method using a 0.5% by weight n-hexylamine solution, and then developed for 120 seconds by ultrasonic waves. However, it could not be developed and a pattern could not be formed.

[0062]

[Table 3]

[0063]

EFFECT OF THE INVENTION A high aspect ratio using a photolithography method for enhancing the degree of fine processing of a ceramic substrate material having excellent dimensional stability and a low dielectric loss tangent so that sufficient characteristics can be obtained in a high frequency region. It is possible to obtain a multilayer substrate material and a method of manufacturing a multilayer substrate, which are capable of forming a via hole with a relatively high definition.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mitsuyo Haruba             1-1-1 Sonoyama, Otsu, Shiga Prefecture Toray shares             Company Shiga business site (72) Inventor Takenori Ueoka             1-1-1 Sonoyama, Otsu, Shiga Prefecture Toray shares             Company Shiga business site

Claims (4)

[Claims] 1. A ceramic using a photosensitive ceramic composition comprising inorganic particles and a photosensitive organic component, wherein 30% by weight or more of the inorganic particles are inorganic particles having an average particle diameter of 420 nm or less. A method for producing a ceramic substrate, which is a method for developing a substrate, comprising at least one type of developing step selected from a spray method and a dipping method and a developing step by ultrasonic waves. 2. The method for producing a ceramic substrate according to claim 1, wherein a photosensitive ceramic composition in which the average particle size of the inorganic particles is 100 nm or less is used. 3. The developer is at least one selected from an aqueous alkaline metal solution containing an alkali metal and / or an alkaline earth metal and an organic alkaline aqueous solution containing an amine compound.
The method for manufacturing a ceramic substrate according to claim 1, wherein the developing solution is one of the types. 4. The size of cations present in the developing solution is 0.
It is 6 nm or less, The manufacturing method of the ceramic substrate of Claim 3 characterized by the above-mentioned.