JPH10229016A - Insulating paste for inductor, inductor and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow having a high inductor characteristic and high self resonance frequency in a high frequency area by controlling the average refractive index of the inorganic component of an insulating paste within a specific range and forming a conductive material layer and an insulating material layer by lamination. SOLUTION: Inorganic powder having an average refractive index of 1.45-2.3 is used as a material for forming an insulating layer, and an inductor having an inductor characteristic (Q value) and a high self resonance frequency at approximately 10-2,000MHz is formed. A high Q value and a high self resonance frequency at approximately 100-1,000MHz is obtained by controlling the average refractive index of the inorganic powder to be 1.5-1.9. The average refractive index N1 and the average refractive index N2 of an organic component are set to satisfy the following inequality; -0.1<=N1-N2<=0.2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an insulating paste for forming an insulating layer for an inductor, an inductor using the insulating paste, and a method of manufacturing an inductor using the insulating paste.

[0002]

2. Description of the Related Art Conventional inductors are mainly wound around a magnetic wire (copper wire) around a magnetic core (core), but recently, various types of mobile phones, PHSs, pagers, and other mobile communication fields have been developed. There is a demand for inductors mounted on equipment and automobile equipment to be used in a high frequency range and to be downsized. However, it has become difficult to obtain sufficient characteristics with the winding type.

[0003]

That is, the present invention provides:
An object of the present invention is to provide an inductor having a high Q value and a high self-resonant frequency (SRF) in a high frequency region suitable for the above-mentioned application, not a conventional wire-wound type, a method of manufacturing the same, and an insulating paste for forming the inductor. I do.

[0004]

An object of the present invention is to set the average refractive index of the inorganic component of the insulating paste for forming the insulating layer to 1: 1.
By controlling to 45 to 2.3, the problem is solved in an inductor formed by laminating a layer made of a conductive material and a layer made of an insulating material. This insulating paste contains an inorganic powder and an organic component as essential components, and is characterized in that the inorganic powder has an average refractive index of 1.45 to 2.3.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the use of an inorganic powder having an average refractive index of 1.45 to 2.3 as a material for forming an insulating layer allows inductor characteristics (Q value) at 10 to 2000 MHz and self resonance. It has been found that an inductor having a high frequency can be formed. Further, by controlling the average refractive index of the inorganic powder to 1.5 to 1.9, 100
A high Q value and a high self-resonant frequency can be obtained at ~ 1000 MHz. More preferably, by controlling the average refractive index of the inorganic powder to 1.5 to 1.7,
A high Q value and a high self-resonant frequency can be obtained at 1000 MHz.

A method for forming a multilayer inductor will be described below. However, the present invention is not limited to this. First, an insulating paste is formed on a supporting substrate by a printing method. On the insulating layer pattern, a conductor pattern such as a coil pattern and a half turn (L-shape) of the coil pattern is formed by a printing method using a conductive paste. Subsequently, an insulating pattern having a through hole such that a part of the conductive pattern is exposed is formed by a printing method using an insulating paste, and a printing method is performed on the insulating pattern so that the conductive pattern is connected to the preceding conductive pattern. Is formed. The above steps are repeated several times to form a multilayer body, and then firing is performed to form a multilayer inductor. However, baking may be performed every time each layer is formed.

[0007] As a method of forming a pattern for an insulating layer, a screen in which a desired pattern is covered with a photosensitive emulsion or the like is formed on a screen made of a stainless steel screen, a polyester screen, a silk screen, or the like, and the paste is passed through the pattern using a squeegee. By using a screen printing method of printing on a substrate by using a method, a pattern can be formed well. However, other printing means may be used.

When the insulating layer is formed by screen printing, the thickness is usually 10 to 100 μm (after firing, 5 to 80 μm), so that the printing and drying are repeated 1 to 8 times. . The thickness of the coating film can be adjusted by selecting the number of coatings, the mesh of the screen, and the viscosity of the paste. The viscosity of the paste when formed by the screen printing method is appropriately adjusted depending on the method of applying the paste, but the range is preferably 0.5 to 500 Pa · S. The paste viscosity can be measured using a B-type viscometer and an E-type viscometer. The paste viscosity is preferably 20 to 200 Pa · S in order to obtain a film thickness of 10 to 20 μm by applying once by a screen printing method. Further, it is preferably 1 to 200 Pa · S. When the viscosity is less than 0.5, only one thin film is obtained after printing, and printing must be repeated several times in order to thicken the applied film. If the viscosity is higher than 500 Pa · S, clogging of a screen plate or the like is likely to occur.

A step of applying a photosensitive insulating paste on a substrate by using a photosensitive compound as an organic component of the insulating paste;
A method for forming a pattern by a method including a leveling step, a drying step, an exposure step, and a development step is also preferably performed.

Further, a fine pattern of 50 μm or less can be formed by using a photosensitive resin component as an organic component.

When a photosensitive compound is used, the steps of applying a photosensitive insulating paste include methods such as screen printing, a bar coater method, a dip method, a doctor blade method, a spinner method, a roll coater method, and a die coater method. Can be applied.

Next, the photosensitive insulating film uniformly coated on the substrate is heated at 70 to 100 ° C. for several minutes to 1 hour to evaporate and dry the solvents, and then exposed and developed through a photomask. A predetermined pattern or via hole is formed.

Exposure is performed using an exposure apparatus. The exposure is generally performed by a mask exposure using a photomask, as performed by ordinary photolithography.
As the mask to be used, either a negative type or a positive type can be selected depending on the type of the photosensitive organic component.
Alternatively, a method of directly drawing with a red or blue laser beam without using a photomask may be used.

As the exposure device, a stepper exposure device, a proximity exposure device, or the like can be used. The active light source used at this time is, for example, visible light, near ultraviolet light,
Ultraviolet rays, electron beams, X-rays, laser beams and the like can be mentioned, and among them, ultraviolet rays are preferable. Among these, an ultra-high pressure mercury lamp is preferable. Exposure conditions vary depending on the coating thickness.
Using an ultra-high pressure mercury lamp with an output of 00 KW, 1 to 1000
An exposure of 0 mJ / cm ² can be performed for 1 to 30 minutes.

By providing an oxygen blocking film on the surface of the applied photosensitive insulating paste, pattern formability can be improved. As an example of the oxygen barrier film, a film of polyvinyl alcohol or cellulose, or a film of polyester or the like can be given.

After exposure, development is carried out using a developing solution. In this case, immersion, showering, spraying, and brushing can be used. An organic solvent in which the organic components in the paste can be dissolved can be used. Water may be added to the organic solvent as long as the solvent does not lose its solubility. When a carboxyl group is present in the photosensitive paste, development can be performed with an aqueous alkali solution. As the alkali aqueous solution, a metal alkali aqueous solution such as a sodium hydroxide or calcium hydroxide aqueous solution can be used, but it is preferable to use an organic alkali aqueous solution since the alkali component can be easily removed at the time of firing.

As a specific example of the organic alkali, an amine compound can be used. For example, tetramethylammonium hydroxide, trimethylbenzylammonium hydroxide, monoethanolamine, diethanolamine and the like can be mentioned. The concentration of the aqueous alkali solution is usually 0.01 to 10% by weight, more preferably 0.1 to 5% by weight.
% By weight. If the alkali concentration is too low, it becomes difficult to remove the soluble portion, which is not preferable. If the alkali concentration is too high, the concentration of the developing solution is too strong, which may cause peeling of the pattern portion and corrosion of the exposed portion, which is not preferable. The development time varies from 20 to 120 seconds, depending on the type and pattern size of the exposed pattern. The developer temperature is
It is preferably carried out between 10 ° C and 50 ° C. Further, after the development, by performing shower rinsing with water, the eluate and the developer remaining between the lines of the pattern and at the end portions can be removed.

The baking can be carried out by a method of performing each baking, or a method of performing baking at a time after printing or laminating a plurality of sheets.

As a furnace for firing, an electric furnace, a belt furnace, a diffusion furnace, a siliconite furnace, a muffle furnace, and the like can be used. The firing atmosphere and temperature vary depending on the type of the substrate, but the firing is usually performed at 600 to 1000 ° C. in air. Preferably, it is performed at 750 ° C to 900 ° C.

As a method for forming a conductive pattern, a screen is used in which a desired pattern is formed in advance on a screen made of a stainless steel screen, a polyester screen, a silk screen, or the like using a photosensitive emulsion or the like, and a paste is printed on the substrate through the pattern using a squeegee. Printing methods can be used. When a photosensitive compound is used as an organic component of the conductive paste, a method of forming a pattern by performing a step of applying the photosensitive conductive paste on a substrate, a leveling step, a drying step, an exposure step, and a development step is also preferable. Done. Alternatively, a method in which a pattern formed on a film by a printing method and a photolithography method is transferred to a substrate to form a desired pattern can be used.

As a method of forming a laminated inductor, P
A method using a green sheet formed by applying an insulating paste on a film such as ET using a method such as a doctor method, screen printing, a bar coater method, a dip method, or a spinner method can also be used. Forming a conductor to be a via hole conductor and a conductor film to be a coil pattern,
A method of forming an inductor by stacking and firing several layers can also be mentioned.

The via formation of the green sheet can be performed by using a punching method or a laser method. Also, when a photosensitive compound is used as an organic component of the insulating paste,
By performing the exposure step and the development step in the same manner as in the case of the photosensitive insulating paste, a via can be formed.

As a method for forming a conductor pattern on the green sheet, a screen printing method, a photolithography method, and a transfer method can be used. The photolithography method can be formed by applying a photosensitive conductive paste on a green sheet, and then performing an exposure step and a development step. At this time,
In order to prevent the green sheet from being eroded by the photosensitive conductive paste, the surface treatment of the green sheet is preferably performed using a surface treatment liquid. The surface processing is mainly performed to form a resin in which the organic composition in the paste is insoluble on the sheet. Alternatively, a method in which a coil pattern previously formed on a film by a printing method or a photolithography method is transferred to a green sheet and formed may be used. The transfer property can be improved by subjecting the film to a release treatment with a fluorine compound, a silicone compound, or the like in advance. The transfer can be performed by setting the temperature of the press material at 20 ° C. to 100 ° C. using a press machine and adjusting the press pressure.

Further, a heating step at 50 ° C. to 300 ° C. may be introduced for the purpose of drying and preliminary reaction during each of the coating, exposure, development and baking steps. The method for producing the insulating paste is described below, but the present invention is not limited to this. Usually, the paste is prepared by mixing inorganic powder and organic components so as to have a predetermined composition, and uniformly mixing and dispersing the mixture with a three-roller and a kneader.

The viscosity of the paste is appropriately adjusted by the addition ratio of an inorganic powder, a thickener, an organic solvent, a plasticizer, a suspending agent, etc., but the range is from 2000 to 200,000 cps.
(Centipoise).

The insulating glass powder which is an inorganic powder used in the present invention includes ferrite, cordierite, forsterite, alumina, silica, mullite,
An insulating material containing at least one of cristobalite, corundum (α-alumina), zirconia, calcium oxide, magnesium oxide, chromium oxide, lithium oxide, boron oxide, iron oxide, zinc oxide, nickel oxide, and borosilicate glass; A glass powder having a refractive index of 1.45 to 2.3 is preferable, and more preferably 1.5 to 2.3 in order to improve the Q value, which is an inductor characteristic, with an insulating material containing a metal component of an oxide. 1.
9, more preferably in the range of 1.5 to 1.7.

In the present invention, the measurement of the refractive index is preferably performed by a generally performed ellipsometry method or V-block method, and the measurement is preferably performed by using light having a wavelength in the range of 350 to 650 nm. Further, the i-line (365n
m), h-line (406 nm) or g-line (436 nm)
Is preferred. When a photosensitive resin is used, it is more preferable to use the photosensitive resin at the wavelength of the light to be exposed in order to confirm the effect.

The average particle size of the inorganic powder is D50 of 1 to 6 μm.
m, maximum particle size 30 μm or less, specific surface area 1.5
It is desirably 〜4 m ² / g. More preferably D
10 is 0.4 to 2 μm, D50 is 1.5 to 6 μm, D9
0 is 4 to 15 μm and the maximum particle size is 25 μm
Hereinafter, it is preferable to have a specific surface area of 1.5 to 3.5 m ² / g. More preferably, D50 is 2 to 3.5 μm.
m, the specific surface area is 1.5 to 3 m ² / g.

Here, D10, D50 and D90 are glass particle diameters of 10% by volume, 50% by volume and 90% by volume, respectively, of the inorganic powder having a small particle diameter.

By using the inorganic powder having the above particle size distribution, the filling property of the powder is improved, and even if the powder ratio in the photosensitive paste is increased, the entrapment of air bubbles is reduced, resulting in extra light scattering. Is small, so that a preferable pattern shape can be formed. When the particle size distribution is in the above range, the powder filling ratio is high, so that the shrinkage ratio during firing is low, and a stable pattern is obtained without breaking the pattern shape during firing. When the particle size is smaller than the above range, the specific surface area increases, the cohesiveness of the powder increases, and the dispersibility in the organic component decreases, so that bubbles are easily entrained. For this reason, light scattering increases and the bottom is hardened insufficiently and peels off during development, making it difficult to form a pattern. When the average particle size is larger than the above range, the bulk density of the powder is reduced, so that the filling property is reduced and bubbles are easily entrapped, light scattering is also increased, and the surface roughness of the pattern after application is also increased. Accuracy decreases.

The method for measuring the particle size is not particularly limited, but it is preferable to use a laser diffraction / scattering method because it can be measured easily. For example, Microtrac particle size distribution diameter HR
The measurement conditions when using A9320-X100 are as follows.

Sample amount: 1 g Dispersion conditions: ultrasonic dispersion in purified water for 1 to 1.5 minutes.

When it is difficult to disperse, it is carried out in 0.2% sodium hexametaphosphate.

Particle refractive index: changed depending on the type of inorganic powder Solvent refractive index: 1.33 Number of measurements: 2 times In order to improve the dispersibility of the powder in the paste, a bulk density of 0.1 to 2 g / cc was used. Powder having a tap density of 0.3 to 4 g / cc is preferably used. The shape of the inorganic powder may be plate-like, conical, rod-like, or the like, but is preferably a monodisperse, non-aggregated, spherical shape. In this case, the spherical shape preferably has a sphericity of 80% by number or more. For the measurement of the sphericity, the powder was photographed with an optical microscope at a magnification of 300 times and counted, and the ratio of spheres was expressed. When the shape is spherical, the scattering of ultraviolet light during exposure is very small, and a highly accurate pattern can be obtained.

The organic components of the insulating paste of the present invention include binder components such as polymers, monomers and oligomers, solvents,
Thermal polymerization inhibitor, plasticizer, thickener, antioxidant, dispersant,
It is preferable to add an organic or inorganic suspending agent, a leveling agent and the like.

As the binder in the organic component, polyvinyl alcohol, polyvinyl butyral, methacrylate polymer, acrylate polymer, acrylate-methacrylate copolymer, α-methylstyrene polymer, butyl methacrylate resin, etc. Can be used.

With respect to the insulating paste of the present invention, the coating film has excellent surface flatness and the surface center line roughness (Ra) of the coating film.
It is preferable to add a leveling agent to the paste so that the particle size is 2 μm or less. The leveling agent is preferably an organic substance, and more preferably an acrylic polymer and a modified vinyl polymer having a molecular weight of 300 to 3,000, which are commercially available as the leveling agent. Organic leveling agents are preferred because they provide a higher leveling effect than inorganic (silicone) types, and thermally decompose without leaving the leveling agent during binder removal. Leveling agents containing inorganic insulating materials,
If it remains after firing, it becomes difficult to design the dielectric constant and expansion coefficient. An organic surfactant, preferably a nonionic organic surfactant, can be used as the leveling agent.

Specific examples of the addition of the leveling agent include:
"Dispalon" (L-1) in which an acrylic polymer or a modified vinyl polymer having a molecular weight of 300 to 3,000 is dissolved in a solvent such as petroleum naphtha, xylol, toluene, ethyl acetate, 1-butanol, and mineral terpene.
980-50, L-1982-50, L-1983-3-5
0, L-1984-50, L-1985-50, # 19
70, # 230, LC-900, LC-951, # 19
20N, # 1925N, P-410) (all manufactured by Kusumoto Kasei Co., Ltd.), nonionic surfactant "color sparse 18"
8-A "," Hyonic PE Series "," Modicol L "," Daplo "(S-65, U-99, W-7
7) It is preferable to add 0.1 to 10 parts by weight of the above (manufactured by San Nopco Co., Ltd.) to the paste. By adding these leveling agents, the paste viscosity is reduced to 0.1.
At 5 to 500 Pa · S, it is possible to obtain an application surface in which pinholes and screen printing mesh residue do not remain.

Here, Ra means a reference length (L) extracted from the roughness curve in the direction of the average line, and the X axis is set in the direction of the average line of the extracted portion, and the Y axis is set in the direction of the vertical magnification. When a roughness curve is represented by y = f (x), a value obtained by the following equation is represented by a micrometer (μm).

[0040]

(Equation 1) The measurement was performed using a stylus type surface roughness measuring instrument.

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

The antioxidant is added to prevent oxidation of the acrylic copolymer during storage. Specific examples of antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, and 2,6-di-t.
-4-ethylphenol, 2,2-methylene-bis-
(4-methyl-6-t-butylphenol), 2,2-
Methylene-bis- (4-ethyl-6-t-butylphenol), 4,4-bis- (3-methyl-6-t-butylphenol), 1,1,3-tris- (2-methyl-6
-T-butylphenol), 1,1,3-tris- (2
-Methyl-4-hydroxy-t-butylphenyl) butane, bis [3,3-bis- (4-hydroxy-3-t-
[Butylphenyl) butyric acid] glycol ester, dilaurylthiodipropionate, triphenylphosphite and the like. When the antioxidant is added, the addition amount is usually 0.01 to the total amount of the glass powder, the acrylic copolymer having an ethylenically unsaturated group in the side chain, the photoreactive compound and the photopolymerization initiator. -5% by weight, more preferably 0.1-1% by weight. If the amount of the antioxidant is small, the effect of preventing oxidation of the acrylic copolymer during storage cannot be obtained, and if the amount of the antioxidant is too large, the residual ratio of the exposed portion may be too small.

When the organic component constituting the insulating paste contains a photosensitive compound, it is particularly effective to add a thermal polymerization inhibitor. The thermal polymerization inhibitor is added to improve thermal stability during storage. Specific examples of the thermal polymerization inhibitor include hydroquinone, N-nitrosodiphenylamine, phenothiazine, pt-butylcatechol, and N
-Phenylnaphthylamine, 2,6-di-t-butyl-
p-Methylphenol, chloranil, pyrogallol and the like. When a thermal polymerization inhibitor is added, the amount of addition is usually based on the sum of the acrylic copolymer having an ethylenically unsaturated group in the side chain and the photoreactive polymerizable compound.
It is 0.1 to 20% by weight, more preferably 0.5 to 10% by weight. If the amount of the thermal polymerization inhibitor is too small, the effect of improving the thermal stability during storage is not exhibited, and if the amount of the thermal polymerization inhibitor is too large, the residual ratio of the exposed portion may be too small. is there.

The insulating paste of the present invention preferably contains a photosensitive compound as an organic component.
The content of the photosensitive compound is preferably at least 10% by weight of the organic component from the viewpoint of sensitivity to light. Further, it is preferably at least 30% by weight.

The photosensitive compound in the present invention is an organic component containing a photosensitive compound in the photosensitive insulating paste. As the photosensitive compound, there are a photo-insolubilizing type and a photo-solubilizing type. As the photo-insolubilizing type, (1) monomers, oligomers having one or more functional groups such as unsaturated groups in the molecule, (2) Photosensitive compounds such as aromatic diazo compounds, aromatic azide compounds, and organic halogen compounds (3) So-called diazo resins such as condensates of diazo-based amines and formaldehyde There is.

Examples of the photo-soluble type include (4) a complex of a diazo compound with an inorganic salt or an organic acid, and quinonediazides. (5) a quinonediazido compound bonded to a suitable polymer binder, for example, phenol or novolak. Examples of the resin include naphthoquinone 1,2-diazide-5-sulfonic acid ester.

In the present invention, all of the above (1) to (5) can be used. Above all, regarding (1),
The following compounds are preferable in terms of ease of handling and ease of quality design, but are not limited thereto.

Specific examples of the photosensitive monomer having a functional group in the molecule include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, sec-butyl acrylate, Isobutyl acrylate, tert-butyl acrylate, n-
Pentyl acrylate, allyl acrylate, benzyl acrylate, butoxyethyl acrylate, butoxytriethylene glycol acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, 2-ethylhexyl acrylate, glycerol acrylate, glycidyl acrylate, heptadecafluorodecyl acrylate, 2-
Hydroxyethyl acrylate, isobonyl acrylate, 2-hydroxypropyl acrylate, isodexyl acrylate, isooctyl acrylate, lauryl acrylate, 2-methoxyethyl acrylate, methoxyethylene glycol acrylate, methoxydiethylene glycol acrylate, octafluoropentyl acrylate, phenoxyethyl acrylate, Stearyl acrylate, trifluoroethyl acrylate, allylated cyclohexyl diacrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate Acrylate, dipen Erythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, ditrimethylolpropane tetraacrylate, glycerol diacrylate, methoxylated cyclohexyl diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate, polypropylene glycol diacrylate, triglycerol diacrylate, triglycol Methylolpropane triacrylate, acrylamide, aminoethyl acrylate,
Phenyl acrylate, phenoxyethyl acrylate, benzyl acrylate, 1-naphthyl acrylate, 2-naphthyl acrylate, bisphenol A diacrylate, diacrylate of bisphenol A-ethylene oxide adduct, diacrylate of bisphenol A-propylene oxide adduct, thiophenol acrylate Acrylates such as benzyl mercaptan acrylate, styrene, p-methylstyrene, o-
Styrenes such as methylstyrene, m-methylstyrene, α-methylstyrene, chloromethylstyrene, and hydroxymethylstyrene, and some or all of the hydrogen atoms in these aromatic rings are converted to chlorine, bromine atoms, iodine or fluorine. Substituted ones, acrylates in which some or all of the acrylates in the molecule of the above compound are changed to methacrylates, γ-methacryloxypropyltrimethoxysilane, 1-vinyl-2-pyrrolidone, and the like are mentioned.

In the present invention, one or more of these can be used. In addition to these, the developability after exposure can be improved by adding an unsaturated acid such as an unsaturated carboxylic acid. Specific examples of the unsaturated acid include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, and acid anhydrides thereof.

On the other hand, examples of oligomers and polymers having a functional group in the molecule include oligomers and polymers obtained by polymerizing at least one of the above-mentioned monomers and having one or more functional groups in the molecule. Alternatively, an oligomer or polymer having no functional group and a functional group added to a side chain or a molecular terminal of a polymer can be used. By containing at least an alkyl acrylate or an alkyl methacrylate, and more preferably containing at least methyl methacrylate, a polymer having good thermal decomposability can be obtained.

Preferred functional groups are those having an ethylenically unsaturated group. Examples of the ethylenically unsaturated group include a vinyl group, an allyl group, an acryl group, and a methacryl group.

A method for adding such a functional group to an oligomer or a polymer is to use an ethylenically unsaturated compound having a glycidyl group or an isocyanate group or an acrylic acid for a mercapto group, an amino group, a hydroxyl group or a carboxyl group in the polymer. There is a method in which chloride, methacrylic chloride or allyl chloride is added to make an addition reaction.

Examples of the ethylenically unsaturated compound having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, glycidyl ethyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, and glycidyl isocrotonic acid. Examples of the ethylenically unsaturated compound having an isocyanate group include (meth) acryloyl isocyanate,
(Meth) acryloylethyl isocyanate and the like.

The ethylenically unsaturated compound having a glycidyl group or an isocyanate group, acrylic acid chloride, methacrylic acid chloride, or allyl chloride is used in an amount of 0.05 to less than 0.05 to the mercapto group, amino group, hydroxyl group and carboxyl group in the polymer. It is desirable to add 0.8 molar equivalent, more preferably 0.1 to 0.6.
It is a molar equivalent. If it is less than 0.05 molar equivalent, the allowable development width is narrow, and the cutting of the pattern edge tends to be poor,
On the other hand, if the molar ratio is larger than 0.8 molar equivalent, the solubility of the developer in the unexposed portion tends to decrease.

The developability after exposure can be improved by copolymerizing an unsaturated acid such as an unsaturated carboxylic acid. Specific examples of the unsaturated acid include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetic acid, and acid anhydrides thereof.

The thus obtained oligomer or polymer having an acidic group such as a carboxyl group in the side chain has an acid value (AV) of preferably from 50 to 180, more preferably from 70 to 140. More preferably, it is in the range of 80 to 120. If the acid value is less than 50 or more than 180, the allowable development width is narrow, and the edge of the pattern tends to be poor. If it exceeds 180, the hardness of the coating film tends to decrease.

It is preferable to use the photosensitive monomer in an amount of 0.05 to 10 times the amount of the oligomer or the polymer. More preferably, the amount is 0.1 to 3 times. If the amount exceeds 10 times, the viscosity of the paste becomes small, and the uniformity of dispersion in the paste may be reduced. If the amount is less than 0.05 times, the solubility of the unexposed portion in the developer tends to be poor.

In the present invention, an ultraviolet absorber is added for forming a pattern having excellent line linearity. By adding a light absorbing agent having a high ultraviolet absorbing effect, a pattern with excellent line breaks and no bleeding or edge curl can be obtained.

That is, usually, with the insulating glass powder alone, the ultraviolet rays are scattered by the insulating glass powder having a size of 1 μm or less or the insulating glass powder having a non-uniform shape, and light-cured to an excessive part, so that a pattern as an exposure mask cannot be formed. For this reason, it is likely that portions other than the mask cannot be developed. The present inventors have conducted intensive studies on the cause, and as a result, it has been found that the scattered ultraviolet light is absorbed or weakened and reaches the light-shielded portion by the exposure mask. Therefore, the scattered light is substantially prevented from wrapping around by adding the ultraviolet light absorbing agent, the curing of the photosensitive compound in the mask portion is prevented, and a pattern corresponding to an exposure mask is formed.

As an ultraviolet absorber, 250 to 520 nm
And those having a high UV absorption coefficient in the wavelength range of 350 to 450 nm are preferably used. As organic dyes, azo dyes, aminoketone dyes, xanthene dyes, quinoline dyes, aminoketone dyes, anthraquinone dyes, benzophenone dyes, diphenylcyanoacrylate dyes, triazine dyes, p-aminobenzoic acid dyes and the like can be used. Even when an organic dye is added as a light-absorbing agent, it is preferable because it does not remain after baking and can reduce deterioration of film properties. Among these, azo dyes and benzophenone dyes are preferred. As typical azo dyes, Sudan Blue (Su
_{dan Blue, C 22 H 18 N} 2 O 2 = 342.4),
Sudan _{R (C 17 H 14 N 2} O 2 = 278.31), Sudan
II (C ₁₈ H ₁₄ N ₂ O = 276.34), Sudan III (C
₂₂ H ₁₆ N ₄₀ = 352.4), Sudan IV (C ₂₄ H ₂₀ N ₄
O = 380.45), Oil Orange SS (Oil O
range SS, CH ₃ C ₆ H ₄ N: NC ₁₀ H ₆ OH
= 262.31) Oil Violet (Oil Vio
let, C ₂₄ H ₂₁ N ₅ = 379.46), Oil Yellow OB (Oil Yellow OB, CH ₃ C ₄ H ₄₎
N: NC ₁₀ H ₄ NH ₂ = 261.33).

As benzophenone dyes, Ubinal D-50 (C ₁₃ H ₁₀ O ₅ = 246.22, 2,2 ′,
4,4′-tetrahydroxybenzophenone), ubinal MS40 (C ₁₄ H ₁₂ O ₆ S = 308, 2-hydroxy-4-methoxybenzophenone 5-sulfonic acid), ubinal DS49 (C ₁₅ H ₁₂ O ₁₁ S ₂ Na) ₂ =
478, 2,2-dihydroxy-4,4'-dimethoxybenzophenone-5,5'-sodium disulfonate), and dyes that can absorb at 250 to 520 nm can be used.

The amount of the ultraviolet absorber added is 0.01 to 1
% By weight is preferred. More preferably 0.01 to 0.3
%, More preferably 0.02 to 0.2% by weight. If the amount is less than 0.01% by weight, the effect of addition is low, and the effect of eliminating cuts or bleeding of the pattern and curling of the edge portion is small. If it exceeds 1% by weight, the effect of absorbing ultraviolet rays becomes too large, so that the film is easily peeled off during development, and it is difficult to form a pattern with good edge sharpness.

The surface treatment of the insulating glass powder used in the present invention with a stabilizer is preferably performed as follows. When using benzotriazole as a stabilizer, a predetermined amount of benzotriazole is dissolved in an organic solvent such as methyl acetate, ethyl acetate, ethyl alcohol, or methyl alcohol with respect to the insulating glass powder. 1 in the solution so that it can be immersed in
Soak for ~ 24 hours. After immersion, preferably 20-30 ° C
The powder is air dried under reduced pressure to evaporate the solvent to prepare a powder which has been subjected to a triazole treatment. The ratio of the stabilizer (stabilizer / powder) used in the present invention is preferably from 0.1 to 50% by weight, and more preferably from 0.4 to 30% by weight. If it is less than 0.2% by weight, it is ineffective in preventing the crosslinking reaction of the polymer and gels in a short time. Also 5
If the amount exceeds 0% by weight, the amount of the stabilizer becomes too large, and the sensitivity of the photosensitive paste is lowered. Further, in the above case, the presence of a small amount of water in the insulating glass powder promotes the gelation of the paste. In order to prevent this, it is preferable to dry the powder at 150 ° C. to 600 ° C. for 1 to 2 hours in the air or under vacuum to sufficiently remove the adsorbed moisture and crystallization water on the powder surface since gelation can be prevented.

In the present invention, it has been found that, when the average refractive index N1 of the inorganic powder and the average refractive index N2 of the organic component in the insulating paste satisfy the following formula, an insulating layer having via holes with excellent dimensional accuracy can be formed. .

-0.1≤N1-N2≤0.2 More preferably, by satisfying -0.05≤N1-N2≤0.1, a high aspect ratio via hole having excellent dimensional accuracy is formed. Can be.

More preferably, -0.01≤N1-N
2 ≦ 0.07.

Further, considering that the refractive index of the organic component is improved by polymerization, a pattern having more excellent line linearity can be formed by satisfying the following expression.

0 ≦ N1−N2 ≦ 0.07 Further, the refractive index N after the organic component is polymerized by light irradiation.
By satisfying the following expression for the average refractive index N1 of No. 3 and the inorganic powder, a pattern having excellent lie linearity can be formed.

-0.03 ≦ N1-N3 ≦ 0.03 Among the insulating pastes of the present invention, those containing a photosensitive compound as an organic component include a sensitizer, a sensitization aid, a photopolymerization accelerator, It is also preferable to add a thermal polymerization inhibitor, a thickener, an antioxidant, a dispersant, an organic or inorganic precipitation inhibitor, and the like.

When a photosensitive resin is used, a sensitizer is added to improve high sensitivity. Specific examples of the sensitizer include 2,4-diethylthioxanthone, isopropylthioxanthone, 2,3-bis (4-diethylaminobenzal) cyclopentanone, 2,6-bis (4-dimethylaminobenzal) cyclohexanone, 2,6-bis (4-dimethylaminobenzal) -4-methylcyclohexanone, Michler's ketone, 4,4-bis (diethylamino) -benzophenone, 4,4-bis (dimethylamino) chalcone, 4,4-bis (diethylamino) ) Chalcone, p-dimethylaminocinnamylidene indanone, p
-Dimethylaminobenzylidene indanone, 2- (p-
Dimethylaminophenylvinylene) -isonaphthothiazole, 1,3-bis (4-dimethylaminobenzal) acetone, 1,3-carbonyl-bis (4-diethylaminobenzal) acetone, 3,3-carbonyl-bis (7
-Diethylaminocoumarin), N-phenyl-N-ethylethanolamine, N-phenylethanolamine,
Examples thereof include N-tolyldiethanolamine, N-phenylethanolamine, isoamyl dimethylaminobenzoate, isoamyl diethylaminobenzoate, 3-phenyl-5-benzoylthio-tetrazole, 1-phenyl-5-ethoxycarbonylthio-tetrazole and the like. In the present invention, one or more of these can be used.

Some sensitizers can also be used as photopolymerization initiators. When a sensitizer is added to the insulating paste of the present invention, the amount added is usually 0.1 to the sum of the acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in the side chain and the photoreactive compound. -30% by weight, more preferably 0.5-15% by weight. If the amount of the sensitizer is too small, the effect of improving the photosensitivity is not exhibited, and if the amount of the sensitizer is too large, the residual ratio of the exposed portion may be too small.

The preferred composition of the insulating paste is preferably selected in the following range.

(A) insulating powder: 70 to 98% by weight based on the sum of (a) and (b) (b) organic binder; 2 to 2 based on the sum of (a) and (b)
30% by weight (c) leveling agent; based on the sum of (a) and (b)
1 to 10% by weight Within these ranges, it is possible to form a pattern with good cutting properties of the side line, and the insulating layer after firing becomes dense.

The preferred composition of the photosensitive insulating paste is preferably selected in the following range.

(A) Insulating powder; 70 to 95% by weight based on the sum of (a) and (b) (b) Photoreactivity with acrylic copolymer having carboxyl group and ethylenically unsaturated group in side chain Compound; (a),
20 to 5% by weight based on the sum of (b) (c) Photopolymerization initiator; 2 to 30 based on (b)
% By weight (d) UV absorber; 0.05 based on (a)
More preferably, the composition of the components (a), (b) and (d) is 80 to 92% by weight,
7% by weight and 0.1-0.4% by weight. Within this range, ultraviolet rays are well transmitted at the time of exposure, the function of photocuring is sufficiently exhibited, and the occurrence of residual film at the unexposed portion during subsequent development can be almost eliminated, and the sharpness of the side line can be reduced. A good pattern can be formed. The proportion of the insulating powder is in the above preferred range, and the total amount of the acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in the side chain as the component (b) and the photoreactive compound is defined as this range. Thereby, the insulating layer after firing becomes dense.

Among the insulating pastes of the present invention, those containing a photosensitive compound as an organic component, further include:
An acrylic copolymer having a carboxyl group and an ethylenically unsaturated group in the side chain and a photopolymerization initiator are dissolved in a photoreactive compound, and an ultraviolet absorber is dispersed in this solution to contain a mixture. When the acrylic copolymer having an ethylenically unsaturated group in the side chain and the photopolymerization initiator are not dissolved in the photoreactive compound, a mixed solution of the acrylic copolymer, the photopolymerization initiator and the photoreactive compound May be added. Examples of the organic solvent used at this time include methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl ethyl ketone, dioxane, acetone, cyclohexanone, cyclopentanone, isobutyl alcohol, isopropyl alcohol, tetrahydrofuran, dimethyl sulfoxide, γ-butyrolactone, and the like. An organic solvent mixture containing at least one of the following is used.

Further, when a photosensitive compound is contained as an organic component, the preparation, printing, exposure and development steps of the insulating paste must be performed in a place where ultraviolet rays can be blocked.
Otherwise, the paste or the coating film will be photo-cured by ultraviolet rays, and an insulating layer that can exhibit a photosensitive effect cannot be obtained.

As the conductor material used by being laminated with the insulating layer of the present invention, a powder conductor material made of silver, copper, silver-palladium, silver-platinum or the like is preferably used. The method of forming the conductor
A method of etching after forming a metal film by sputtering or vapor deposition, a method of forming by screen printing using a thick film paste composed of a metal powder and an organic component, a method of forming by a photolithographic method using a photosensitive conductive paste, and the like. It is preferably used. It is also preferable to include a glass frit in these pastes.

[0079]

【Example】

Examples 1 to 10 Examples will be specifically described below, but the present invention is not limited thereto. In the following examples, all parts are by weight unless otherwise specified. The materials used are shown in A to K below. Table 1 shows the paste composition and the evaluation results.

A. Insulating powder powder Insulating powder (1): SiO2 (82% by weight), Al2 O3
(1% by weight), B2O3 (12.4% by weight), CaO
(0.1% by weight), ZrO ₂ (0.2% by weight), K ₂ O
(2% by weight) MgO (1.1% by weight), Na ₂ O (0.
6% by weight), Fe ₂ O ₃ (0.6% by weight) Insulating powder (2); SiO 2 (62.5% by weight), Al 2 O
3 (3% by weight), B2O3 (12% by weight), CaO
(0.1% by weight), ZrO ₂ (0.2% by weight), K ₂ O
(2% by weight), MgO (15% by weight), Na ₂ O (0.
1 _{wt%), Fe 2 O 3 (} 0.1 wt%) insulating powder (3); SiO2 (73.5 wt%), Al2 O
3 (2% by weight), B2O3 (12% by weight), CaO
(0.1% by weight), ZrO ₂ (0.2% by weight), K ₂ O
(2% by weight), MgO (10% by weight), Na ₂ O (0.
1% by weight), Fe ₂ O ₃ (0.1% by weight) Insulating powder (4); Ca0 (48% by weight), Fe ₂ O ₃ (52%
%) After the glass powder is made into fine powder with an attractor in advance,
It was manufactured by spheroidizing in a plasma stream. Insulating powder
(1) Particle diameter D10 is 1.2 μm, D50 is 3.5 μm
m, D90 is 6.2 μm, sphericity is 96% by number, glass transition point is 575 ° C, yield point is 703 ° C, insulating powder (2)
The particle diameters of D10 were 1.5 μm, D50 was 3.4 μm, D
90 is 7.4 μm, the sphericity is 98% by number, the glass transition point is 605 ° C., the deformation point is 728 ° C., the insulating powder (3) has a particle diameter of 1.6 μm for D10, 3.5 μm for D50, and 8.8 for D90. 4 μm, sphericity is 92% by number, glass transition point is 60
A powder having 0 ° C. and a sag point of 632 ° C. was used. For measurement of sphericity, the powder was photographed with an optical microscope at a magnification of 300 times,
Countable particles are counted, and the ratio of spherical particles is represented.

B. UV absorbers Organic dyes; Azo-based dyes; Sudan C.I. Polymer binder Polymer (1); Ethyl cellulose Polymer (2); 40% methacrylic acid (MAA), 3
0% methyl methacrylate (MMA) and 30%
Polymer obtained by adding 0.4 equivalents (corresponding to 40%) of glycidyl methacrylate (GMA) to a carboxyl group (MAA) of a styrene (St) copolymer. The acid value of the polymer was 95.

D. B. Monomer Monomer (1); Trimethylol-propane-triacrylate (TMPTA) Monomer (2); Trimethylol-propane-triacrylate-modified PO ("TPA-330") Leveling agent “Dispalon LC-951” F.I. Solvent γ-butyrolactone (γ-BL) ethanol propanol G. Photopolymerization initiator 2-methyl-1- [4- (methylthio) phenyl] -2
Morpholinopropanone-1 Sensitizer 2,4-diethylthioxanthone (DETX-S) Photopolymerization accelerator p-dimethylaminobenzoic acid ethyl ester (EPA) Plasticizer dibutyl phthalate (DBP) Thickener Aerosil (SiO ₂ ) was dissolved in 2- (2-butoxyethoxy) ethyl acetate and a solution of 15 parts by weight of SiO ₂ was added.

<Preparation of Insulating Paste> a. Preparation of Organic Component The solvent and the polymer binder were mixed so as to form a 50% solution, and heated to 80 ° C. with stirring to dissolve all the polymer binders uniformly. The solution is then added to 400
It filtered using the filter of a mesh.

B. Surface Treatment of Insulating Powder A benzotriazole / ethyl acetate solution was prepared so that the ratio of benzotriazole / insulating powder = 9 g / 100 g, and the powder was immersed overnight in a refrigerator in a sealed condition. The next day, it was air-dried to evaporate the ethyl acetate to prepare a triazole-treated powder.

C. Preparation of paste The paste is prepared by adding an insulating powder, a leveling agent, and a plasticizer to the above organic components so as to have a predetermined composition.
It was prepared by mixing and dispersing with this roller. Table 1 shows the prepared compositions.

<Preparation of photosensitive insulating paste> a. Preparation of Organic Component The solvent and the polymer binder were mixed so as to form a 50% solution, and heated to 80 ° C. with stirring to dissolve all the polymer binders uniformly. Then, the solution was cooled to room temperature, and a photopolymerization initiator, a sensitizer and a photopolymerization accelerator were added and dissolved. Thereafter, this solution was filtered using a 400 mesh filter.

B. Surface Treatment of Insulating Powder A benzotriazole / ethyl acetate solution was prepared so that the ratio of benzotriazole / insulating powder = 9 g / 100 g, and the powder was immersed overnight in a refrigerator in a sealed condition. The next day, it was air-dried to evaporate the ethyl acetate to prepare a triazole-treated powder.

C. Preparation of Light-Absorptive Additive Powder A predetermined amount of an organic dye was weighed, a dispersant was added to a solution of the organic dye dissolved in isopropyl alcohol (IPA), and the mixture was homogeneously stirred with a homogenizer. Next, a predetermined amount of insulating glass powder was added to this solution, and the mixture was uniformly dispersed and mixed, and then dried at a temperature of 150 to 200 ° C. using a rotary evaporator to evaporate IPA. In this way, a powder in which the surface of the glass powder was uniformly coated with a film of an organic dye (so-called capsule treatment) was produced.

D. Preparation of paste The paste is prepared by mixing the above organic components with a photoreactive compound, a light-absorbing agent-added powder (glass encapsulated with an organic dye), a thickener, an organic leveling agent, and a plasticizer to a predetermined composition. It was prepared by mixing and dispersing with three rollers. Table 1 shows the prepared compositions.

<Production of Inductor> Materials used A1: Support substrate (96% alumina substrate, 76 mm square, 0.63
A2; insulating paste A3; photosensitive insulating paste A4; conductive paste A5; photosensitive conductive paste B. Lamination procedure B1; An insulating layer was formed on the A1 substrate using the A2 insulating paste or the A3 photosensitive insulating paste.

B2: A conductive layer was formed on the insulating layer formed in B1 by using a conductive paste of A4 or a photosensitive conductive paste of A5.

B3: An insulating layer having a through hole connectable to the conductor layer formed in B2 was formed using the paste of A1 or A2.

B4: A conductive paste was buried in the through-holes of the insulating layer formed in B3 and connected to the conductive layer formed in B2.

B5: A conductor layer to be connected to the conductor formed in B4 was formed on the insulating layer formed in B3 by using a conductor paste of A4 or A5.

B6: An insulating layer was formed on the conductor layer formed by using B5 using an insulating paste of A2 or A3.

C. Pattern forming method C1; Pattern forming method using insulating paste of A2 (Examples 1, 3, 5, 7, 9, 11) On the substrate of A1,
An insulating paste was applied by a screen printing method of A2 using a 325 mesh screen on which a desired pattern was formed. Coating and drying are repeated 3 times and 40 μm
. Drying on the way was performed at 80 ° C. for 15 minutes. After completion of the coating, the coating was dried at 80 ° C. for 40 minutes.

C2: Pattern forming method using photosensitive insulating paste of A3 (Examples 2, 4, 6, 8, 10, 12) On a substrate of A1, a screen of 325 mesh was used by a screen printing method. A3 photosensitive insulating paste was applied over the entire surface. Coating and drying were repeated three times to obtain a film thickness of 40 μm. Drying on the way was performed at 80 ° C. for 15 minutes. After completion of the coating, the coating was dried at 80 ° C. for 40 minutes.

A negative-type chrome mask was placed on the coating film, and ultraviolet rays of 1 J / cm ² were irradiated from the upper surface of the mask using an ultrahigh-pressure mercury lamp of 2 kW output. Next, the film is immersed in a 0.5% by weight aqueous solution of monoethanolamine kept at 25 ° C. for 1 minute for development, and thereafter, a space portion of the pattern that has not been photocured is washed and removed using a water shower spray, followed by drying. A pattern was formed on the back and front surfaces of the substrate without leaving any residue.

C3: Pattern forming method using conductive paste of A4 (Examples 1, 3, 5, 7, 9, 11) Using a 325 mesh screen on which a desired pattern is formed, A4 is formed by a screen printing method. Was applied. The coating and drying were repeated twice to obtain a film thickness of 15 μm. Drying on the way was performed at 80 ° C. for 15 minutes. After application, 8
It was kept at 0 ° C. for 40 minutes and dried.

C4: Pattern forming method using the photosensitive insulating paste of A5 (Examples 2, 4, 6, 8, 10, 12) The photosensitive insulating paste of A5 was screen-printed using a 325-mesh screen. Was applied over the entire surface. The coating and drying were repeated twice to obtain a film thickness of 15 μm. Drying on the way is 8
Performed at 0 ° C. for 15 minutes. After completion of the coating, the coating was dried at 80 ° C. for 40 minutes. Next, a negative-type chrome mask was placed on the coating film, and ultraviolet light of 1 J / cm ² was irradiated from the upper surface of the mask using an ultrahigh-pressure mercury lamp with a 2 kW output. Next, the film is immersed in a 0.5% by weight aqueous solution of monoethanolamine kept at 25 ° C. for 20 seconds for development, and thereafter, the space portion of the pattern that has not been photocured is washed and removed using a water shower spray, followed by drying. Then, a pattern with no residue left was formed on the back and front surfaces of the substrate.

C5: Firing The insulating film or the conductive film formed by the above methods C1 to C4 was fired in air at 850 ° C. for 10 minutes.

<Evaluation> Evaluation of Insulating Layer The pattern shape (via shape: 100 μm square and 50 μm square, film thickness before firing: 40 μm) of the alumina substrate on which the insulating layer was formed was observed with an electron microscope. When the via shape was square and there was no clogging, it was evaluated as 、, when the via shape was broken but a via was formed, △, and when the via was crushed and could not be formed, it was evaluated as ×.

Measurement of Q value To measure the Q value, a laminated inductor was manufactured. First, the insulating paste is applied by screen printing, and then the internal electrode layer paste (15 μmt) and the insulating paste (40 μmt) are alternately laminated by screen printing.
After drying, a green laminate was obtained. Next, after cutting the green laminate into green chips, 85
Firing was performed in an atmosphere of 0 ° C. to produce an inductor. The Q value of this inductor at 100 MHz and 800 MHz was measured.

<Examples 1, 3, 5, 7, 9>
In 3, 5, 7, and 9, the average refractive index of the inorganic powder was 1.
An inductor formed using powder of 54, 1.52, and 1.53. The Q value in a high frequency region is 10 to 100 MHz.
High values of 16 to 50 could be obtained at 20, 800 MHz.

<Examples 2, 4, 6, 8, and 10> In Examples 2, 4, 6, 8, and 10, powders having an average refractive index of the inorganic powders of 1.54, 1.52, and 1.53 were used. In the inductor formed using the high frequency region, 100M
High Q of 10-20 at Hz and 16-50 at 800MHz
Value was obtained.

In the case where a photosensitive paste containing a photosensitive compound in an organic composition is used, the size and shape of the photosensitive paste are preferably 50 μm.
A square via hole was formed.

<Comparative Example 1> Using the insulating powder (4), the composition shown in Table 1 was mixed, and mixed and dispersed with three rollers to produce an insulating paste.

In the pattern formation, the steps C1, C3 and C5 were repeated to form a pattern and an inductor by the method of the lamination procedure B. However, many via holes were clogged.
The Q value at 800 MHz could not be measured.

<Comparative Example 2> Using the insulating powder (4), the composition shown in Table 1 was mixed, and mixed and dispersed with three rollers to produce a photosensitive insulating paste.

In the pattern formation, the steps C2, C4, and C5 were repeated to form a pattern and an inductor by the method of lamination procedure B. However, many via holes were clogged.
The Q value at 800 MHz could not be measured.

[0111]

[Table 1]

[0112]

According to the present invention having the above-described structure, the Q value of the inductor characteristic is increased in the high frequency region, the width and the bottom of the pattern are not disturbed, the film thickness is uniform, and the center line surface roughness is reduced. It has been found that two or less insulating layers can be formed. Moreover, there is an advantage that it can be formed reliably and accurately on a large-sized substrate.

Continued on the front page (72) Inventor Kuniko Kimura 1-1-1, Sonoyama, Otsu-shi, Shiga Pref.

Claims (11)

[Claims] 1. An insulating paste for an inductor, comprising an inorganic powder and an organic component as essential components, wherein the inorganic powder has an average refractive index of 1.45 to 2.3. 2. An insulating paste comprising an inorganic powder and an organic component as essential components, wherein the average refractive index N1 of the inorganic powder and the average refractive index N2 of the organic component satisfy the following expression. paste. −0.1 ≦ N1-N2 ≦ 0.2 3. The photosensitive insulating paste for an inductor according to claim 1, wherein the organic component contains a photosensitive compound. 4. The inductor according to claim 1, wherein the inorganic powder has an average particle size of 1 to 6 μm and a specific surface area of 1.5 to ⁴ m ² / g. Insulating paste. 5. The photosensitive insulating paste according to claim 3, wherein the organic component contains an ultraviolet absorber. 6. An inductor insulating film formed from the insulating paste according to claim 1. 7. A photosensitive insulating film for an inductor, formed from the photosensitive insulating paste according to claim 3. 8. An inductor having an insulating layer having an average refractive index of 1.45 to 2.3. 9. A method of manufacturing an inductor, comprising a step of forming a pattern by at least a printing method using the insulating paste according to claim 1 or 2, and firing the pattern. 10. A process for masking and exposing a portion other than a desired pattern portion of an insulating film formed by the photosensitive insulating paste according to claim 3, developing, and baking to form an insulating layer. A method for manufacturing an inductor, comprising: 11. A step of masking and developing a desired pattern portion of an insulating film formed by the photosensitive insulating paste according to claim 3, developing, and then firing to form an insulating layer. A method for manufacturing an inductor.