JP2002287375A - Method of forming thick-film pattern and photosensitive paste used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of easily and surely forming fine thick-film patterns having excellent dimensional accuracy and shape accuracy by a transfer method and a photosensitive part used for the same. SOLUTION: The thick-film patterns of the prescribed shape are formed by previously measuring the photosetting depth d of a photosensitive paste and applying the photosensitive paste on a base in consideration of this photosetting depth d to form a photosensitive paste film of a prescribed film thickness t on the base, then subjecting the film to exposure processing, transferring the photosensitive paste film subjected to the exposure processing onto a body to be transferred, such as a ceramic green sheet and developing the film. The photosensitive paste is applied on the base in such a manner that the relation between the photosetting depth d of the photosensitive paste and the film thickness t of the photosensitive paste film satisfy conditions of equation: t<=d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a thick film pattern by a transfer method, a photosensitive paste used for forming a thick film pattern, and an electronic component having electrodes formed using the photosensitive paste.

[0002]

2. Description of the Related Art With the increase in the density and the speed of high-frequency electronic devices, the wiring conductors constituting the high-frequency circuits provided in these electronic devices are fine, large in film thickness, and rectangular in cross section. In addition, there is a demand for wiring accuracy in which variations in wiring dimensions are small.

In forming a thick conductive film for forming wiring on a substrate, a conductive paste obtained by mixing a conductive powder with an organic binder is used, and this is formed into a desired pattern on the substrate by screen printing. After being applied so as to provide the organic component, the organic component is baked to remove the organic binder and to sinter the conductive component. However, in the screen printing method, the pattern plate accuracy is not always sufficient, and it is difficult to form a fine pattern of, for example, 100 μm or less.

A method for obtaining a fine pattern which is difficult to obtain by screen printing is disclosed in
As described in JP-A-21967, JP-A-54-13591, and JP-A-59-143149, a photosensitive paste in which a conductive powder is mixed with a photosensitive resin composition is used, and a photo paste is used. There has been proposed a method of forming a conductive film having a fine pattern on a substrate by applying a lithography technique.

Further, with respect to pattern formation on a green sheet, Japanese Patent Application Laid-Open No. 63-99596 discloses a transfer method for forming a thick film pattern on a plurality of supports and transferring the pattern onto a green sheet. Have been. This transfer method has the feature that, compared to the case of forming a thick film pattern on a green sheet by screen printing, bleeding and blurring can be suppressed, and a fine thick film pattern can be formed with high precision. Have.

However, in this method, since a thick film pattern is formed on a support by a screen printing method, the width and pitch of the thick film pattern are limited to about 50 μm.

Also, Japanese Patent Application Laid-Open Nos. 10-75039, 10-200260, 10-2093
No. 34, No. 34, etc., in the transfer method described above, a thick film pattern is formed on a support by a photolithography method using a photosensitive paste (photosensitive conductive paste).
A method of transferring this to a ceramic green sheet has been proposed. According to this method, it is possible to form an extremely fine thick film pattern having a width and a pitch of 50 μm or less while suppressing blurring and blurring of the thick film pattern.

In such a photosensitive paste, as the photosensitive resin composition constituting the paste component, a conventionally known photopolymerizable or photo-modified compound can be used. A mixture of a monomer or oligomer having a reactive functional group such as a photopolymerization initiator such as an aromatic carbonyl compound, (2) a so-called diazo resin such as a condensate of an aromatic bisazide and formaldehyde,
(3) A mixture of an addition polymerizable compound such as an epoxy compound and a photoacid generator such as a diallyl iodonium salt, and (4) a naphthoquinonediazide compound can be used. Among them, particularly preferred is a mixture of the monomer (1) having a reactive functional group such as an unsaturated group and a photoradical generator such as an aromatic carbonyl compound.

[0009]

By the way, in order to obtain a conductive layer having high electric conductivity, it is necessary to prevent defects such as disconnection and cracks due to volume shrinkage during firing. It is necessary to increase the content ratio of the conductive powder mixed with the conductive resin composition. However, when the content ratio of the conductive powder increases, the transmittance of light in the photosensitive paste decreases, and the curing of the paste inside the paste due to the curing of the photosensitive resin composition becomes insufficient. It may be difficult to form a pattern.

Further, as shown in FIG.
Even if the wiring (thick film pattern) 52 can be formed thereon, there is a problem that the cross-sectional shape becomes an inverted trapezoidal shape, and dimensional variation and shape variation increase.

Then, in such a state, as shown in FIG. 4B, when the thick film pattern 52 on the support 51 is transferred onto a transfer object such as a ceramic green sheet 53,
As shown in FIG. 4C, when the width of the wiring (thick film pattern) 52, the interval between the wirings 52, the deformation of the thickness of the wiring 52, and the like are not constant, and the wiring has a very small pitch, There is a problem that it is very difficult to form a precise wiring pattern due to contact between adjacent wirings.

The above problem does not only apply to photosensitive paste containing conductive powder as inorganic powder, but also applies to photosensitive paste containing insulating powder as inorganic powder.

The present invention solves the above-mentioned problems. Even when a photosensitive paste having a high conductive powder content and a low light transmittance is used, the dimensional variation and the shape variation are reduced by the transfer method. Provided is a method for forming a thick film pattern capable of reliably forming a thick film pattern, a photosensitive paste used for forming the thick film pattern, and a highly reliable electronic component having electrodes formed using the photosensitive paste. The purpose is to do.

[0014]

Means for Solving the Problems The inventor of the present invention has conducted intensive studies to solve the above-mentioned problems, and as a result, has determined that the thickness of the photosensitive paste film is equal to the photocuring depth of the photosensitive paste film.
Or, when smaller than that, the cross-sectional shape on the support is rectangular, the transfer amount is constant even when transferred on a transfer target such as a ceramic green sheet, the deformation during transfer becomes uniform, The inventors have found that a thick film pattern with small dimensional variations can be obtained, and further conducted experiments and studies to complete the present invention.

In other words, the method of forming a thick film pattern according to the present invention (claim 1) comprises the steps of (a) measuring the photocuring depth d of the photosensitive paste in advance, and (b) considering the photocuring depth d. Applying the photosensitive paste on a support to form a photosensitive paste film having a predetermined thickness t; (c) performing an exposure process on the photosensitive paste film; and (d) exposing process. Developing the photosensitive paste film that has been performed, to form a thick film pattern of a predetermined shape on the support, (e)
Transferring the thick film pattern formed on the support onto the transfer target.

From the photocuring depth d of the photosensitive paste and the thickness t of the photosensitive paste film, the shape (cross-sectional shape) of the thick film pattern to be formed can be predicted to some extent.
Measure the photo-curing depth d of the photosensitive paste in advance,
In consideration of this photo-curing depth d, the thickness t of the photosensitive paste film
By defining, it becomes possible to efficiently form a thick film pattern having a desired cross-sectional shape on the support,
By transferring the thick film pattern formed on the support onto the object to be transferred, it is possible to efficiently form a thick film pattern with high shape accuracy on the object to be transferred.

In the present invention, the transfer object is defined as
The thick film pattern formed on the support is a target to be transferred, and is a concept generally meaning a substrate or the like, but is not limited to the substrate, and the thick film pattern formed on the support is transferred. This is a broad concept including various objects.

When the thickness of the photosensitive paste film is slightly larger than the photocuring depth, the cross-sectional shape of the thick film pattern formed on the support tends to be somewhat inverted trapezoidal. If the thick film pattern to be formed does not require such a high degree of shape accuracy, use such a film thickness (thickness somewhat larger than the depth of photocuring) as the film thickness of the photosensitive paste film. Is also possible.

In the present invention, the photosensitive paste means a paste containing an inorganic powder and a photosensitive resin component, and if necessary, a storage stabilizer such as a solvent and a polymerization inhibitor, and an antioxidant. It is also possible to add agents, dyes, pigments, defoamers, surfactants and the like as appropriate. There are no particular restrictions on the type or composition of the photosensitive paste, and photosensitive pastes of various compositions can be used as long as the essential effects of the present invention are exhibited.

In the present invention, a photosensitive paste film is a film made of a photosensitive paste by a known technique such as screen printing or spin coating.
This is a concept meaning a film which is applied to a substrate such as a film and dried, and the thickness of the photosensitive paste film is a concept meaning the thickness of the film.

The photo-curing depth d of the photosensitive paste film is defined as “irradiated light, for example, ultraviolet light, travels through the paste film and is consumed for curing of the resin or absorbed by the resin component. This is a concept that means "depth from the paste film surface until the energy is attenuated and falls below the minimum energy required for curing the resin."

As a method of evaluating (measuring) the photocuring depth d, for example, the following method is exemplified. First, a photosensitive paste film is formed on a substrate by a screen printing method. Then, exposure is performed by irradiating light (for example, ultraviolet light) whose energy amount is adjusted to be constant. Thereafter, development is performed using a dilute aqueous solution of sodium carbonate or the like, the uncured portion is removed, the thickness of the cured film is measured, and the thickness is defined as the photocuring depth d. The thickness can be measured by a known method such as an optical microscope, an electron microscope, and a laser microscope.

According to a second aspect of the present invention, in the method for forming a thick film pattern, the relationship between the photocuring depth d of the photosensitive paste and the film thickness t of the photosensitive paste film is defined by the following condition: t ≦ d. The photosensitive paste is applied to the support so as to satisfy the following.

The photosensitive paste is applied so as to satisfy the above condition: t ≦ d, that is, by making the thickness t of the photosensitive paste film equal to or smaller than the photocuring depth d, The photosensitive paste film can be surely cured over the entire thickness direction and can be prevented from being dissolved during development. Therefore, it is possible to reliably form a thick film pattern having a desired cross-sectional shape.

Further, in the method of forming a thick film pattern according to claim 3, when the average particle diameter of the inorganic powder in the photosensitive paste is m, the thickness t of the photosensitive paste film is represented by the following formula: The photosensitive paste is applied so as to satisfy the condition of t ≦ d + m (where d is the photocuring depth of the photosensitive paste).

When the content ratio of the inorganic powder is increased, the probability that the inorganic powder is present on the surface of the photosensitive paste film is increased, so that the average particle size of the inorganic powder in the photosensitive paste is m.
In this case, even when the thickness t of the photosensitive paste film satisfies the above condition: t ≦ d + m, the photosensitive paste film can be hardened substantially over the entire thickness direction. Will be possible. Therefore, a thick film pattern having a desired cross-sectional shape can be reliably formed, and a thick film having good adhesion to an object (usually a substrate) on which the thick film pattern is to be formed and having excellent shape accuracy. A pattern can be efficiently formed.

According to the method for forming a thick film pattern according to the third aspect, for example, even when the content ratio of an inorganic powder such as a conductive powder is high and the light transmittance inside is low, it is ensured. It is possible to form a thick film pattern having a desired shape. In addition, the average particle diameter m of the inorganic powder is a concept meaning the average particle diameter of the inorganic powder contained most when two or more kinds of inorganic powders are used.

According to a fourth aspect of the present invention, there is provided a method of forming a thick film pattern, wherein a cross-sectional shape of the thick film pattern formed on the support in a direction orthogonal to a longitudinal direction is rectangular.

By applying the photosensitive paste so as to satisfy the above condition: t ≦ d, the photosensitive paste film can be surely hardened over the entire thickness direction and can be prevented from being dissolved during development. And on the support,
By forming a thick film pattern having a rectangular cross section in the direction perpendicular to the longitudinal direction, it is possible to form an electrode having a rectangular cross section even after transfer baking, and current concentration is likely to occur on the electrode surface. To prevent the formation of pointed parts,
It is possible to suppress concentration of current and improve transmission characteristics at high frequencies.

That is, when the thickness of the paste is larger than the depth of photocuring, the degree of undercut occurring at the time of development increases, and the cross-sectional shape tends to be inverted trapezoidal. Therefore, when the thick film pattern to be formed does not require high shape accuracy, the thickness of the photosensitive paste film can be set to be slightly larger than the photocuring depth, but the cross-sectional shape is rectangular. However, when a thick film pattern with high shape accuracy is to be formed, it is necessary that the thickness t of the photosensitive paste film does not exceed the photocuring depth d.

The photosensitive paste of the present invention (claim 5) is a photosensitive paste containing an inorganic powder having an average particle size of m, which is used for forming a thick film pattern on a support, The photocurable depth d of the photosensitive paste film, the thickness t of the photosensitive paste film, and the average particle size m of the inorganic powder are used in such a manner as to satisfy the following formula: t ≦ d + m. And

In the photosensitive paste of the present invention, the photocuring depth d of the photosensitive paste film, the thickness t of the photosensitive paste film, and the average particle size m of the inorganic powder satisfy the above condition: t ≦ d + m. Used in such a manner, the applied and formed photosensitive paste film, to be surely cured over the entire thickness direction by exposure, has a desired shape, and high accuracy of shape accuracy, dimensional accuracy It is possible to reliably form a film pattern.

Further, the photosensitive paste according to claim 6 is characterized in that the photosensitive paste is used for forming a thick film pattern having a rectangular cross section in a direction perpendicular to the longitudinal direction.

Using the photosensitive paste of the present invention, the thick film pattern on the support is hardened over the entire thickness direction by exposure to light, and then is transferred to a transfer target, so that it is perpendicular to the longitudinal direction. It is possible to reliably form a thick film pattern having a rectangular shape and high shape accuracy and high dimensional accuracy on the transfer target.

Further, an electronic component according to the present invention (claim 7) is characterized in that electrodes are formed using the photosensitive paste according to claim 5.

As in the case of the electronic component according to the seventh aspect, the electronic component in which the electrode is formed by using the photosensitive paste of the present invention (the fifth aspect) has high electrode shape accuracy and dimensional accuracy and high reliability. It can be realized.

An electronic component according to an eighth aspect is characterized in that an electrode having a rectangular cross section in a direction perpendicular to the longitudinal direction is formed using the photosensitive paste according to the sixth aspect.

An electrode having a rectangular cross section in a direction perpendicular to the longitudinal direction is less likely to cause current concentration, and can improve high-frequency transmission characteristics.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of forming a thick film pattern according to the present invention is advantageously used, for example, when a film having a fine pattern is formed on a substrate by using photolithography technology. Next, a method for forming a thick film pattern according to the present invention will be specifically described with reference to FIG.

First, as shown in FIG. 1A, a photosensitive paste (photosensitive conductor paste) is applied on the support 1 by a method such as spin coater, screen printing, doctor blade method, and the like. 2 hours, 50-150 ° C
To form a photosensitive paste film 2. Next, as shown in FIG. 1B, an actinic ray from a high-pressure mercury lamp or the like is applied to the photosensitive paste film 2 on the support 1 through a photomask 5 on which a desired pattern is drawn.
Irradiation is performed at an exposure amount of about 0 to 5000 mJ / cm ² . As a result, the light-irradiated portions (exposed portions) 3a and 3b are hardened and become regions that are not developed by the subsequent development processing. Then, as shown in FIG. 1C, the exposure units 3a and 3b
A general-purpose alkaline aqueous solution such as a sodium carbonate aqueous solution is applied to the photosensitive paste film 2 including the unexposed portions 2a, 2b, and 2c by a method such as a spray shower. As a result, the unexposed portions 2a, 2b, and 2c are dissolved (developed) in the alkaline aqueous solution, and a thick film pattern including the exposed portions 3a and 3b is formed on the support 1. Next, as shown in FIG. 1 (D), the thick film patterns 3a, 3b on the
Thermal transfer onto the ceramic green sheet 6 is performed at 200 MPa and 50 to 150 ° C. for 5 seconds to 5 minutes. Then, by peeling the support 1 from the ceramic green sheet 6, as shown in FIG. 1 (E) and FIG.
Fine and high-definition thick film patterns 3a and 3b are formed on the ceramic green sheet 6.

As a transfer support, for example,
A film-like support such as a polyester film, a polypropylene film, and a nylon film can be used as a suitable support.

In order to improve the transferability of the thick film pattern, a release treatment such as a silicon coat, a wax coat, a melamine coat, etc. may be performed on the film-like support.
In addition, the photosensitive paste of the present invention is excellent in transferability, and usually does not require special release treatment.However, depending on the type of the organic binder used for the ceramic green sheet and the like, the photosensitive paste may be used as a support. In some cases, the peelability from the ceramic green sheet is low.
Appropriate surface treatment can improve the releasability as appropriate.

Although a ceramic green sheet is used as a substrate for forming a thick film pattern here,
There are no special restrictions on the types of ceramics that make up the ceramic green sheet. The invention can be applied.

The method of forming a thick film pattern according to the present invention is not limited to the case where a thick film pattern is formed on a ceramic green sheet, but may be applied to various applications such as the case where a thick film pattern is formed on a printed board or the like. It is possible to apply to. Further, in the present invention, any of a negative type and a positive type photosensitive paste can be used as the photosensitive paste.

The photosensitive resin component (photosensitive organic component) constituting the photosensitive paste of the present invention is a photopolymerizable compound or a photomodified compound, and includes, for example, (1) an unsaturated group A mixture of a monomer or oligomer having a reactive functional group such as an aromatic carbonyl compound and a photopolymerization initiator; (2) a so-called diazo resin such as a condensate of an aromatic bisazide and formaldehyde; and (3) an epoxy compound. And a photoacid generator such as a diallyl iodonium salt, and (4) a naphthoquinonediazide compound. Among them, particularly preferred is a mixture of a monomer having a reactive functional group such as an unsaturated group and a photoradical generator such as an aromatic carbonyl compound.

Examples of the reactive functional group-containing monomer / oligomer include hexanediol triacrylate, tripropylene glycol triacrylate, trimethylolpropane triacrylate, stearyl acrylate, tetrahydrofurfuryl acrylate, lauryl acrylate, 2-phenoxyethyl acrylate, and the like. Isodecyl acrylate, isooctyl acrylate, tridecyl acrylate, caprolactone acrylate, ethoxylated nonylphenol acrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, diethylene glycol diacrylate,
Tetraethylene glycol diacrylate, triethylene glycol diacrylate, ethoxylated bisphenol A diacrylate, propoxylated neopentyl glycol diacrylate, tris (2-hydroxyethyl)
Isocyanurate triacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, propoxylated trimethylolpropane triacrylate, propoxylated glyceryl triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hydroxypentaacrylate,
Ethoxylated pentaerythritol tetraacrylate,
Tetrahydrofurfuryl methacrylate, cyclohexyl methacrylate, isodecyl methacrylate, lauryl methacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, diethylene glycol dimethacrylate, 1,9-nonane Diol diacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, ethoxylated bisphenol A dimethacrylate, trimethylolpropane trimethacrylate, ethoxylated isocyanuric acid diacrylate, ethoxylated Paramyl phenol acrylate,
Examples include ethylhexyl carbitol acrylate, N-vinyl-2-pyrrolidone, isobornyl acrylate, polypropylene glycol diacrylate, polyethylene glycol diacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and the like.

Examples of the photopolymerization initiator which can be suitably used in the present invention include benzyl, benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoyl benzoic acid, methyl benzoyl benzoate and 4-benzoyl. -4'-methyldiphenyl sulfide, benzyl dimethyl ketal, 2-n-butoxy-4-dimethylaminobenzoate, 2-chlorothioxanthone, 2,4
-Diethylthioxanthone, 2,4-diisopropylthioxanthone, isopropylthioxanthone, 2-dimethylaminoethylbenzoate, ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3′-dimethyl-4-methoxybenzophenone, , 4-dimethylthioxanthone, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-
Propan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, methylbenzoylformate, 1-phenyl-
1,2-propanedione-2- (o-ethoxycarbonyl) oxime, 2-benzyl-2-dimethylamino-1
-(4-morpholinophenyl) -1-butanone, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2
4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -2,4,4-trimethylpentylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,
4,4-trimethylpentylphosphine oxide, 1
-(4-isopropylphenyl) -2-hydroxy-2
-Methylpropan-1-one, 1,2-diphenylethanedione, methylphenylglyoxylate and the like. These photopolymerization initiators can be used alone or in combination of two or more.

In the present invention, the photopolymerization initiator is added in an amount of 0.1 to 5 with respect to 100% by weight of the photosensitive paste.
It is desirable to be in the range of weight%. This is because, if the amount of the photopolymerization initiator is less than 0.1% by weight, curing by light is insufficient, which is not preferable, and even if it exceeds 5% by weight, the curability is almost improved. It cannot be done.

Among the photosensitive pastes to which the photosensitive organic components have been added, particularly preferred are those containing an acrylic copolymer having a carboxyl group in the side chain, and the acrylic copolymer Can be produced by copolymerizing an unsaturated carboxylic acid and an ethylenically unsaturated compound.

As unsaturated carboxylic acids, acrylic acid,
Examples include methacrylic acid, maleic acid, fumaric acid, vinyl acetic acid, and anhydrides thereof. On the other hand, as the ethylenically unsaturated compound, methyl acrylate, acrylates such as ethyl acrylate, methyl methacrylate, methacrylates such as ethyl methacrylate,
And fumarate esters such as monoethyl fumarate. Further, an unsaturated bond may be introduced by subjecting a copolymer obtained by copolymerizing these compounds to an oxidation treatment or the like.

When a conductive powder is used as the inorganic powder in the photosensitive paste, the conductive powder may be Ag powder, Au powder, Pt powder, Pd powder, Cu powder, Ni powder, W powder, Al powder. , Mo powder or the like. It is also possible to use alloyed powder. As these conductive powders, it is possible to use various shapes such as spherical, plate-like, lump-like, rod-like, and needle-like, but it is preferable to use a conductive powder having no aggregation and good dispersibility. Preferably, the average particle size is 0.05 to 10 μm. More preferably, the average particle size is 0.5 to 5 μm. This means that the average particle size of the conductive powder is 0.05 μm
When the average particle diameter of the conductive powder is less than 10 μm, a fine wiring pattern cannot be obtained. It depends.

In the photosensitive paste of the present invention, the content of the conductive powder is preferably in the range of 60 to 90% by weight, and more preferably in the range of 65 to 85% by weight. This is because, when the content ratio of the conductive powder is less than 60% by weight, a disconnection or a crack occurs due to shrinkage during firing, a desired pattern cannot be obtained, and the content ratio of the conductive powder is 90% by weight. %, The amount of the photosensitive resin component becomes insufficient and sufficient curing cannot be obtained.

When an insulating powder is used as the inorganic powder in the photosensitive paste, a glass powder and / or a ceramic powder can be advantageously used as the insulating powder. As the glass powder, a known glass powder such as a borosilicate glass powder can be used, and as the ceramic powder, a crystallized glass, a glass composite type, a non-glass type known ceramic powder can be used. It is.

More specifically, as the glass powder, S
iO ₂ -PbO _system, SiO 2 -ZnO system, _SiO 2 -B
i ₂ O ₃ system, SiO ₂ —K ₂ O system, SiO ₂ —Na ₂ O
System, SiO ₂ —PbO—B ₂ O ₃ system, SiO ₂ —ZnO
—B ₂ O ₃ system, SiO ₂ —Bi ₂ O ₃ —B ₂ O ₃ system, S
_{iO 2 -K 2 O-B 2} O 3 _system, SiO 2 _-Na 2 O-B
It is possible to use a glass powder such as a ₂ O ₃ system.

As the ceramic powder, for example, A
1, Ag, Cu, Ni, Ti, Ba, Pb, Zr, M
It is possible to use an oxide, boride, nitride, silicide, or the like of at least one metal selected from the group consisting of n, Cr, Sr, Fe, Y, Nb, La, Si, Zn, and Ru. .

These insulating powders (inorganic powders) may be spherical, plate-like,
It is possible to use various shapes such as a lump, a rod, and a needle, but it is preferable that there is no aggregation and the dispersibility is good, and for that, the average particle diameter is 0.1 to 10 μm.
It is preferable to use those in the range of m.

When the photosensitive paste contains the above-mentioned glass powder and is used as a paste for forming an insulator, the content ratio of the glass powder is 40 to 40%.
A range of 80% by weight is preferred. This is because if the content of glass powder is less than 40% by weight, the insulation property of the insulating film after firing is lowered, which is likely to be defective. If the content of glass powder exceeds 80% by weight, glass This is because light scattering by the powder makes it difficult to obtain a fine pattern.

Further, the photosensitive paste contains the above-mentioned conductive powder and is used as a paste for forming a conductor, and an insulating powder is further added to such a photosensitive paste for a conductor. In this case, the content ratio of such an insulating powder is preferably in the range of 0.1 to 10% by weight. This is because when the content ratio of the insulating powder is less than 0.1% by weight, the bondability with the substrate is insufficient.
It is difficult to obtain a good pattern, and when the content of the insulating powder exceeds 10% by weight, the conductivity of the pattern after firing and the solderability are reduced.

The photocuring depth of the photosensitive paste film is as follows:
It can be changed by appropriately adjusting the composition of the photosensitive paste. The thickness of the photosensitive paste film is preferably equal to or smaller than the photocuring depth.

More specifically, it is preferable to form the photosensitive paste film in such a manner as to satisfy the following condition. t ≦ d + m (thickness of photosensitive paste film: t, photocuring depth: d, average particle diameter of inorganic powder: m) When the conditions of the above formula are satisfied, the cross-sectional shape after development and transfer to the substrate The cross-sectional shape afterward is rectangular, and the cross-sectional shape after baking is also rectangular, and a thick film pattern with small dimensional variations such as pattern width can be reliably formed. If the thickness t of the photosensitive paste is larger than the above condition, not only the undercut occurs at the time of development, but also the state tends to vary, and the dimensional variation after transfer to the substrate is undesirably large.

[0061]

Hereinafter, embodiments of the present invention will be described together with comparative examples, and features thereof will be described in more detail.

In the examples and comparative examples,
Ag powder having a predetermined average particle size as the inorganic powder,
AgPt powder, Cu powder, SiO ₂ —B ₂ O ₃ —Bi ₂
O ₃ -based glass powder, SiO ₂ —PbO—B ₂ O ₃ -based glass powder and Al ₂ O ₃ (alumina) powder were appropriately used.

In Examples and Comparative Examples, the acrylic copolymer constituting the photosensitive resin component was a methyl methacrylate-methacrylic acid copolymer, and the photoradical polymerizable monomer was ethoxylated. Using trimethylolpropane triacrylate, as a photopolymerization initiator, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one,
4-diethylthioxanthone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-
Butanone was used.

[Preparation of Photosensitive Pastes (A to H)] The above-mentioned inorganic powder, acrylic copolymer, photo-radical polymerizable monomer and photo-polymerization initiator were used together with an organic solvent in the following composition ratios. After sufficient mixing, the following photosensitive pastes A to H were prepared by kneading using three rolls. The photocuring depth and composition of each photosensitive paste are as follows.

<Photosensitive Paste A (Photocuring Depth: 7.8 μm)> Ag Powder (Average Particle Size: 3.0 μm) 75.0% by weight-Methyl methacrylate-methacrylic acid copolymer: 4.5% by weight-Ethoxytrimethylolpropane triacrylate: 5.2% % 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one 1.0% by weight 2,4-Diethylthioxanthone 0.26% by weight 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone 0.14% by weight ・ Ethyl carbitol acetate ... 13.9% by weight

<Photosensitive Paste B (Deep Curing Depth: 9.0 μm)> Ag Powder (Average Particle Size: 3.0 μm) 72.0% by weight ・ SiO ₂ —B ₂ O ₃ —Bi ₂ O ₃ based glass powder 3.0% by weight (average particle size: 3.0 μm) • Methyl methacrylate-methacrylic acid copolymer: 6.0% by weight • Ethoxylated trimethylolpropane triacrylate: 5.8% by weight • 2-methyl -1- [4- (Methylthio) phenyl] -2-morpholinopropan-1-one 0.6% by weight2,4-Diethylthioxanthone ... 0.2% by weight -2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone ... ··················· 0.8% by weight ・ Ethyl carbitol acetate ... 11.6% by weight

<Photosensitive paste C (depth of light curing: 7.3 μm)> Ag powder (average particle size: 1.8 μm) 71.1 _{wt% · SiO 2 -B 2 O 3} -Bi 2 O 3 based glass powder ............... 1.9 wt% (average particle diameter: 3.0 [mu] m) • Methyl methacrylate-methacrylic acid copolymer: 6.0% by weight • Ethoxylated trimethylolpropane triacrylate: 5.8% by weight • 2-methyl -1- [4- (Methylthio) phenyl] -2-morpholinopropan-1-one 0.6% by weight2,4-Diethylthioxanthone ... 0.2% by weight -2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone ... ··················· 0.8% by weight ・ Ethyl carbitol acetate ... 13.6% by weight

<Photosensitive paste D (depth of photocuring: 2.5 μm)> Ag powder (average particle size: 0.6 μm) 71.1 _{wt% · SiO 2 -B 2 O 3} -Bi 2 O 3 based glass powder ............... 1.9 wt% (average particle diameter: 3.0 [mu] m) • Methyl methacrylate-methacrylic acid copolymer: 6.0% by weight • Ethoxylated trimethylolpropane triacrylate: 5.8% by weight • 2-methyl -1- [4- (Methylthio) phenyl] -2-morpholinopropan-1-one 0.6% by weight2,4-Diethylthioxanthone ... 0.2% by weight -2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone ... ··················· 0.8% by weight ・ Ethyl carbitol acetate ... 13.6% by weight

<Photosensitive Paste E (Photocuring Depth: 10.3 μm)> Ag-Pt Powder (Average Particle Size: 2.2 μm) ・ ・ ・ 63.0 weight _{% · SiO 2 -B 2 O 3} -Bi 2 O 3 based glass powder ............... 2.0 wt% (average particle diameter: 3.0 [mu] m) · methyl methacrylate -Methacrylic acid copolymer ... 6.3% by weight-Ethoxylated trimethylolpropane triacrylate ..... 7.2% by weight-2-methyl-1- [ 4- (methylthio) phenyl] -2-morpholinopropan-1-one 1.3% by weight ・ 2,4-diethylthioxanthone・ 0.33% by weight ・ 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone 0.41% by weightEthyl carbitol acetate ..... 19.46% by weight

<Photosensitive Paste F (Light Curing Depth: 4.5 μm)> Cu Powder (Average Particle Size: 3.0 μm) 80.0% by weight-Methyl methacrylate-methacrylic acid copolymer ... 5.1% by weight-Ethoxylated trimethylolpropane triacrylate ... 4.9% by weight % 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one 0.5% by weight 2,4-Diethylthioxanthone 0.2% by weight 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 0.7% by weight ・ Propylene glycol monomethyl ether acetate ・.... 8.6% by weight

<Photosensitive paste G (light curing depth: 40.5 μm)> Al ₂ O ₃ powder (average particle size: 2.5 μm) 0% by weight-Methyl methacrylate-methacrylic acid copolymer: 5.3% by weight-Ethoxytrimethylolpropane triacrylate: 4.7% by weight- 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one 0.6% by weight2,4-diethylthioxanthone ... 0.2 wt% 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone ················· 0.8% by weight ・ Ethyl carbitol acetate・ ・ ・ ・ ・ ・ ・ 8.4% by weight

<Photosensitive Paste H (depth of light curing: 39.8 μm)> SiO ₂ —PbO—B ₂ O ₃ based glass powder: 65.0 weight % (Average particle size: 3.0 μm)-Methyl methacrylate-methacrylic acid copolymer ... 6.3% by weight-Ethoxylated trimethylolpropane triacrylate ...・ 7.2% by weight ・ 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one 0.25% by weight2,4-diethylthioxanthone 0.06% by weight 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl ) -1-butanone 1.73% by weight ・ Ethyl carbitol acetate 10.86% by weight ・ Propylene glycol monomethyl ether acetate 8 0.6% by weight

[Preparation of Samples of Examples 1 to 8] The following samples of Examples 1 to 8 and samples of Comparative Examples 1 to 8 were prepared using the photosensitive pastes A to H described above.

Example 1 A 7.6 μm thick paste film was formed on a PET film by screen printing using a photosensitive paste A having a photocuring depth of 7.8 μm. Then, the photosensitive paste film is exposed to light by irradiating a light beam of an ultra-high pressure mercury lamp at 2000 mJcm- ² through a photomask. A film was formed.

Then, the pattern film on the PET film thus patterned was transferred onto a ceramic green sheet. Transfer conditions are 70 ° C and 50M
Pa was 60 seconds. Then, for the pattern film formed in this manner, (a) the presence or absence of peeling after development is examined, and the cross-sectional shape is observed by microscopic observation. The dimensional variation of the wiring width was obtained by measuring using a microscope, and (c) the cross-sectional shape after transfer firing was evaluated by microscopic observation. The dimensional variation of the wiring width of the transferred pattern was defined by the following equation. Wiring width dimensional variation = maximum width−minimum width The measurement method and definition of the wiring width dimensional variation are the same in each of the following embodiments.

Example 2 A photosensitive paste film having a thickness of 12.0 μm was formed on a PET film by screen printing using photosensitive paste B having a photocuring depth of 9.0 μm. Then, the photosensitive paste film was exposed to light of an ultra-high pressure mercury lamp through a photomask by irradiating it with 2000 mJcm- ^2, and then exposed to sodium carbonate 0.1.
Development was performed with a 5% by weight aqueous solution to form a pattern film on the PET film.

Then, the pattern film on the PET film thus patterned was transferred onto a ceramic green sheet. Transfer conditions are 60 ° C and 75M
Pa and 120 seconds. Then, for the pattern film formed in this manner, (a) the presence or absence of peeling after development is examined, and the cross-sectional shape is observed by microscopic observation. The dimensional variation of the wiring width was obtained by measuring using a microscope, and (c) the cross-sectional shape after transfer firing was evaluated by microscopic observation.

Example 3 An 8.5 μm thick photosensitive paste film was formed on a PET film by screen printing using photosensitive paste C having a photocuring depth of 7.3 μm. Then, the photosensitive paste film was exposed to light of an ultra-high pressure mercury lamp through a photomask by irradiating it with 2000 mJcm ^−2.
Development was performed with a weight% aqueous solution to form a pattern film on the PET film.

Then, the pattern film on the PET film thus patterned was transferred onto a ceramic green sheet. The transfer condition is 50 ° C., 100
MPa and 300 seconds. Then, the wiring width of the transferred pattern was measured using a laser microscope. Then, for the pattern film formed in this manner, (a) the presence or absence of peeling after development is examined, and the cross-sectional shape is observed by microscopic observation. The dimensional variation of the wiring width was obtained by measuring using a microscope, and (c) the cross-sectional shape after transfer firing was evaluated by microscopic observation.

Example 4 A photosensitive paste film having a thickness of 3.0 μm was formed on a PET film using a photosensitive paste D having a photocuring depth of 2.5 μm by a spin coater. Then, the photosensitive paste film was exposed to light of an ultra-high pressure mercury lamp through a photomask by irradiating it with 2000 mJcm ^−2.
Development was performed with a weight% aqueous solution to form a pattern film on the PET film.

Then, the pattern film on the PET film thus patterned was transferred onto a ceramic green sheet. The transfer conditions are 65 ° C and 50M
Pa was 60 seconds. Then, the wiring width of the transferred pattern was measured using a laser microscope. Then, for the pattern film formed in this manner, (a) the presence or absence of peeling after development is examined, and the cross-sectional shape is observed by microscopic observation. The dimensional variation of the wiring width was obtained by measuring using a microscope, and (c) the cross-sectional shape after transfer firing was evaluated by microscopic observation.

Example 5 A photosensitive paste film having a thickness of 12.2 μm was formed on a PET film by screen printing using a photosensitive paste E having a photocuring depth of 10.3 μm. Then, by irradiating a light beam of an ultra-high pressure mercury lamp at 2000 mJcm- ² through a photomask,
After the photosensitive paste film was exposed to light, development was performed with a 0.5% by weight aqueous solution of sodium carbonate to form a pattern film on the PET film.

Then, the pattern film on the PET film thus patterned was transferred onto a ceramic green sheet. Transfer conditions: 75 ° C, 75M
Pa and 30 seconds. Then, for the pattern film formed in this manner, (a) the presence or absence of peeling after development is examined, and the cross-sectional shape is observed by microscopic observation. The dimensional variation of the wiring width was obtained by measuring using a microscope, and (c) the cross-sectional shape after transfer firing was evaluated by microscopic observation.

Example 6 A photosensitive paste film having a thickness of 6.5 μm was formed on a PET film by screen printing using a photosensitive paste F having a photocuring depth of 4.5 μm. Then, the photosensitive paste film was exposed to light of an ultra-high pressure mercury lamp through a photomask by irradiating it with 2000 mJcm ^−2.
Development was performed with a weight% aqueous solution to form a pattern film on the PET film.

Then, the pattern film on the PET film thus patterned was transferred onto a ceramic green sheet. Transfer conditions are 70 ° C and 50M
Pa was 60 seconds. Then, for the pattern film formed in this manner, (a) the presence or absence of peeling after development is examined, and the cross-sectional shape is observed by microscopic observation. The dimensional variation of the wiring width was obtained by measuring using a microscope, and (c) the cross-sectional shape after transfer firing was evaluated by microscopic observation.

Example 7 A photosensitive paste film having a thickness of 35.0 μm was formed on a PET film by screen printing using a photosensitive paste G having a photocuring depth of 40.5 μm. Then, by irradiating a light beam of an ultra-high pressure mercury lamp at 2000 mJcm- ² through a photomask,
After the photosensitive paste film was exposed to light, development was performed with a 0.5% by weight aqueous solution of sodium carbonate to form a pattern film on the PET film.

Then, the pattern film on the PET film thus patterned was transferred onto a ceramic green sheet. Transfer conditions are 70 ° C and 50M
Pa was 60 seconds. Then, the wiring width of the transferred pattern was measured using a laser microscope. Then, for the pattern film formed in this manner, (a) the presence or absence of peeling after development is examined, and the cross-sectional shape is observed by microscopic observation. The dimensional variation of the wiring width was obtained by measuring using a microscope, and (c) the cross-sectional shape after transfer firing was evaluated by microscopic observation.

Example 8 A photosensitive paste film having a thickness of 36.5 μm was formed on a PET film by screen printing using a photosensitive paste H having a light curing depth of 39.8 μm. Then, by irradiating a light beam of an ultra-high pressure mercury lamp at 2000 mJcm- ² through a photomask,
After the photosensitive paste film was exposed to light, development was performed with a 0.5% by weight aqueous solution of sodium carbonate to form a pattern film on the PET film.

Then, the pattern film on the PET film thus patterned was transferred onto a ceramic green sheet. Transfer conditions are 70 ° C and 50M
Pa was 60 seconds. Then, for the pattern film formed in this manner, (a) the presence or absence of peeling after development is examined, and the cross-sectional shape is observed by microscopic observation. The dimensional variation of the wiring width was obtained by measuring using a microscope, and (c) the cross-sectional shape after transfer firing was evaluated by microscopic observation.

Table 1 shows the characteristics of the samples of Examples 1 to 8 measured as described above.

[0091]

[Table 1]

As shown in Table 1, in each of the samples of Examples 1 to 8, a thick film pattern having a small dimensional variation of the wiring width was obtained. In each of the samples of Examples 1 to 8, no peeling was observed in the photosensitive paste film after development, and the cross-sectional shape of the photosensitive paste film after development was rectangular. The cross-sectional shape of the thick film pattern (electrode conductor) was also rectangular. From the above results, it can be seen that according to the present invention, a thick film pattern having a rectangular cross-section, no current concentration, and excellent high-frequency transmission characteristics can be reliably formed.

[Preparation of Samples of Comparative Examples 1 to 8] For comparison, only the thickness of the photosensitive paste film was changed under the same conditions as in Examples 1 to 8 above (that is, the thickness of the photosensitive paste film was smaller than the depth of photocuring). Sample in which the thickness of the photosensitive paste film was increased) (Comparative Example 1)
8), the wiring width of the pattern after transfer was measured using a laser microscope, and the presence or absence of peeling after development, the cross-sectional shape by microscopic observation, and the evaluation of the cross-sectional shape after transfer firing were evaluated. went. The relationship between the thickness of the photosensitive paste films of the samples of Comparative Examples 1 to 8 and the thickness of the photosensitive paste films of Examples 1 to 8 is as follows.

<Comparative Example 1> Film thickness of photosensitive paste film of Example 1: 7.6 μm Film thickness of photosensitive paste film of Comparative Example 1: 10.9 μm Other conditions were the same as Example 1. Comparative Example 2 Film thickness of photosensitive paste film of Example 2: 12.0 μm Film thickness of photosensitive paste film of Comparative example: 12.1 μm Other conditions were the same as Example 2. <Comparative Example 3> Film thickness of photosensitive paste film of Example 3: 8.5 μm Film thickness of photosensitive paste film of Comparative Example 3: 10.8 μm Other conditions were the same as Example 3. Comparative Example 4 Thickness of Photosensitive Paste Film of Example 4: 3.0 μm Film Thickness of Photosensitive Paste Film of Comparative Example 4: 7.5 μm Other conditions were the same as in Example 4. Comparative Example 5 Thickness of Photosensitive Paste Film of Example 5: 12.2 μm Film Thickness of Photosensitive Paste Film of Comparative Example 5: 12.3 μm Other conditions were the same as in Example 5. <Comparative Example 6> Film thickness of photosensitive paste film of Example 6: 6.5 µm Film thickness of photosensitive paste film of Comparative Example 6: 8.8 µm Other conditions were the same as Example 6. Comparative Example 7 Thickness of Photosensitive Paste Film of Example 7: 35.0 μm Film Thickness of Photosensitive Paste Film of Comparative Example 7: 48.3 μm Other conditions were the same as in Example 7. Comparative Example 8 Thickness of photosensitive paste film of Example 8: 36.5 μm Film thickness of photosensitive paste film of Comparative Example 8: 51.4 μm Other conditions were the same as Example 8.

Table 2 shows the characteristics of the samples of Comparative Examples 1 to 8 measured as described above.

[0096]

[Table 2]

From Table 2, it can be seen that, except for Comparative Examples 4 and 6, in each sample of Comparative Example, the dimensional variation of the wiring width was larger than in Examples 1 to 8 described above. In Comparative Examples 3, 4, 6, 7, and 8, including the samples of Comparative Examples 4 and 6 having small dimensional variations in the wiring width, the thickness t of the photosensitive paste film was smaller than the photocuring depth d and the light curing depth. Since the curing depth d is considerably larger than the value of the average particle diameter m of the inorganic powder, the photosensitive paste film after development may peel off, or the cross-sectional shape of the photosensitive paste film after development may be inverted trapezoidal. In addition, the cross-sectional shape of the thick film pattern (line) after the transfer and firing became trapezoidal, and it was not possible to form a thick film pattern having excellent high-frequency transmission characteristics.

On the other hand, in Comparative Examples 1, 2 and 5 in which the thickness t of the photosensitive paste film was slightly larger than the value of the depth of light curing d + the average particle size m of the inorganic powder, Peeling of the conductive paste film was not recognized, or even if it was recognized, it was slight, and the degree to which the cross-sectional shape of the photosensitive paste film after development became an inverted trapezoidal shape was also slight. Furthermore, the degree to which the cross-sectional shape of the thick film pattern (line) after firing was also trapezoidal was slight. However, in Comparative Examples 1, 2, and 5, it can be seen that the dimensional variation of the wiring width of the pattern is large, and it is difficult to obtain a fine and highly accurate thick film pattern.

[Electronic Component According to Embodiment of the Present Invention] FIG. 3 is a sectional view showing an electronic component (ceramic multilayer substrate) according to an embodiment of the present invention. This ceramic multilayer substrate is a ceramic multilayer substrate provided with electrodes (inner layer copper pattern, surface layer copper pattern, etc.) composed of a thick film pattern formed using the photosensitive paste (photosensitive copper paste) of the present invention. .

The ceramic multilayer substrate 11 of this embodiment
Are the insulator layers 12a, 12b, 12c, 12d, 12e
, 12f and the dielectric layers 13a and 13b, and a capacitor pattern, a coil pattern, a strip line, and the like are formed therein by the inner copper pattern 15 and the via hole 16. .

Further, on one main surface of the ceramic multilayer substrate 11, a chip component 20 such as a chip capacitor, a thick film resistor 21, a semiconductor IC 22, and the like are provided.
They are connected to the surface copper pattern 17 and the inner copper pattern 15, respectively. The ceramic multilayer substrate 11
, The inner copper pattern (thick film pattern) 15 and the surface copper pattern (thick film pattern) 17 have a width of about 50 μm.
m, and the film thickness is 5 μm or more.

Next, a method of manufacturing the ceramic multilayer substrate 11 will be described. First, a glass powder, a ceramic powder, and an organic vehicle are mixed to prepare a slurry for an insulator ceramic green sheet. Similarly, a slurry for a dielectric ceramic green sheet is prepared. Next, each of the obtained slurries is formed into a sheet by a doctor blade method or the like, and dried at a temperature of 50 to 150 ° C. to produce an insulating ceramic green sheet and a dielectric ceramic green sheet. In addition, via holes are formed in each ceramic green sheet as necessary.

Further, a photosensitive copper paste according to an embodiment of the present invention having a predetermined light curing depth is prepared, and a photosensitive copper paste is applied on a support to form a photosensitive copper paste film. . The thickness of the photosensitive copper paste film is
Set in consideration of light curing depth.

Then, the photosensitive copper paste film is subjected to an exposure treatment and then developed to form a thick film pattern of a predetermined shape on the support.

Next, the thick film pattern formed on the support is transferred onto the ceramic green sheets (insulator ceramic green sheets and dielectric ceramic green sheets (transfer object)) prepared as described above. Thus, a capacitor pattern, a coil pattern, and the like are formed.

Then, the ceramic green sheets on which the thick film patterns are formed are stacked, pressed and fired at a predetermined temperature. Thereafter, a chip component, a semiconductor IC, and the like are mounted, and a thick film resistor is printed to form the ceramic multilayer substrate 11 as shown in FIG.

In manufacturing the ceramic multilayer substrate 11, a thick film pattern (such as an inner copper pattern or a surface copper pattern) is formed by the thick film pattern forming method of the present invention. A high-precision, fine, and thick film pattern having a large film thickness can be formed on the ceramic green sheet. And
By stacking and compressing the ceramic green sheets on which such thick film patterns are formed, and then baking them at a predetermined temperature, it is possible to efficiently manufacture a ceramic multilayer substrate that is sufficiently compatible with high-speed signaling and high-density wiring. it can.

In the above embodiment, a ceramic multilayer substrate is shown as an electronic component. However, the present invention can be applied to various other electronic components such as a circuit board which is not multilayered. .

The present invention is not limited to the above embodiments and examples in other respects, and various applications and modifications can be made within the scope of the present invention.

[0110]

As described above, in the method of forming a thick film pattern according to the present invention (claim 1), the photocuring depth d of the photosensitive paste is measured in advance, and the photocuring depth d is taken into consideration. Since the thickness t of the photosensitive paste film is determined by the method described above, a thick film pattern having a desired cross-sectional shape can be efficiently formed on the support, and the thickness formed on the support can be improved. By transferring the film pattern onto the transfer object, it is possible to efficiently form a thick film pattern with high shape accuracy on the transfer object such as a ceramic green sheet. As a result, it is possible to easily and surely form an electrode, a resistor, an insulator, or the like having a small pattern dimension variation by using the transfer method.

Further, as in the method of forming a thick film pattern according to claim 2, the photosensitive paste is applied so as to satisfy the condition of t ≦ d, that is, the thickness t of the photosensitive paste film
Is set equal to or smaller than the light curing depth d, the photosensitive paste film can be surely cured over the entire thickness direction and can be prevented from being dissolved at the time of development. Therefore, it is possible to reliably form a thick film pattern having a desired cross-sectional shape.

When the content ratio of the inorganic powder is increased, the probability that the inorganic powder is present on the surface of the photosensitive paste film is increased. When m is set to m, even if the thickness t of the photosensitive paste film satisfies the condition of the formula: t ≦ d + m, the photosensitive paste film can be cured substantially in the entire thickness direction. Will be possible. Therefore, a thick film pattern having a desired cross-sectional shape can be reliably formed, and a thick film having good adhesion to an object (usually a substrate) on which the thick film pattern is to be formed and having excellent shape accuracy. A pattern can be efficiently formed.

Further, by applying the photosensitive paste so as to satisfy the condition of the formula: t ≦ d, it is possible to surely cure the photosensitive paste film in the entire thickness direction so as not to dissolve during development. As described in claim 4, a thick film pattern having a rectangular cross section in a direction perpendicular to the longitudinal direction is formed on the support, and after the transfer firing,
It is possible to form an electrode with a rectangular cross-sectional shape, prevent the formation of sharp points on the electrode surface where current concentration is likely to occur, suppress current concentration, and achieve high-frequency transmission characteristics. Can be improved.

The photosensitive paste according to the present invention (claim 5) has a photocuring depth d of the photosensitive paste film, a thickness t of the photosensitive paste film, and an average particle diameter m of the inorganic powder represented by the following formula: t ≦ d
+ M is used in such a manner that the condition of + m is satisfied. The applied and formed photosensitive paste film is surely cured over the entire thickness direction by exposure, so that it has a desired shape, It is possible to reliably form a thick film pattern with high dimensional accuracy.

Also, using the photosensitive paste of the present invention,
The thick film pattern on the support is hardened over its entire thickness in the thickness direction by exposure, and then transferred to the transfer target, so that the cross-sectional shape in the direction orthogonal to the longitudinal direction is rectangular as in claim 6. Thus, a thick film pattern having high shape accuracy and high dimensional accuracy can be reliably formed on the transfer target.

Further, like the electronic component of the present invention (claim 7), an electronic component having electrodes formed by using the photosensitive paste of the present invention (claim 5) has high electrode shape accuracy and dimensional accuracy. , High reliability can be realized.

The electronic component according to claim 8 is provided.
An electrode having a rectangular cross section in a direction perpendicular to the longitudinal direction is
Concentration of current is less likely to occur and transmission characteristics at high frequencies can be improved.

[Brief description of the drawings]

FIGS. 1A, 1B, 1C, 1D, and 1E are cross-sectional views showing a method of forming a thick film pattern according to an embodiment of the present invention.

FIG. 2 is a plan view showing a method of forming a thick film pattern according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a ceramic multilayer substrate according to one embodiment of the present invention.

4A and 4B are cross-sectional views showing a conventional method of forming a thick film pattern, and FIG. 4C is a plan view showing a formed thick film pattern.

[Explanation of symbols]

Reference Signs List 1 support 2 photosensitive paste film 2a, 2b, 2c unexposed portion 3a, 3b exposed portion (thick film pattern) 5 photomask 6 ceramic green sheet 11 ceramic multilayer substrate 12a, 12b, 12c, 12d, 12e, 12f insulator Layers 13a, 13b Dielectric layer 15 Inner layer copper pattern (thick film pattern) 16 Via hole 17 Surface layer copper pattern (thick film pattern) 20 Chip component 21 Thick film resistor 22 Semiconductor IC

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/20 H05K 3/20 C F term (Reference) 2H025 AA03 AA14 AA19 AB17 AC01 AD01 BC13 BC42 CC08 CC09 EA04 FA29 FA35 2H096 AA27 BA05 EA02 GA08 HA07 5E343 AA02 AA23 BB72 DD03 DD04 DD20 DD56 DD64 FF02 FF12 GG06 GG08

Claims (8)

[Claims] (A) a step of measuring in advance the photocuring depth d of the photosensitive paste; and (b) applying the photosensitive paste on a support in consideration of the photocuring depth d. Forming a photosensitive paste film having a thickness t; (c) performing an exposure process on the photosensitive paste film; and (d) developing the exposed photosensitive paste film to form a support. Forming a thick film pattern having a predetermined shape thereon; and (e) transferring the thick film pattern formed on the support onto a transfer target, forming a thick film pattern. Method. 2. The method according to claim 1, wherein the photosensitive paste is coated on the support such that the relationship between the photocuring depth d of the photosensitive paste and the thickness t of the photosensitive paste film satisfies the following condition: t ≦ d. 2. The method for forming a thick film pattern according to claim 1, wherein the method is applied. 3. When the average particle size of the inorganic powder in the photosensitive paste is m, the thickness t of the photosensitive paste film is represented by the following formula: t ≦ d + m (where d is the photosensitive paste). 3. The method of forming a thick film pattern according to claim 1, wherein the photosensitive paste is applied so as to satisfy the following condition. 4. The thick film pattern according to claim 1, wherein a cross section of the thick film pattern formed on the support in a direction orthogonal to a longitudinal direction is rectangular. Forming method. 5. A photosensitive paste containing an inorganic powder having an average particle size of m, which is used for forming a thick film pattern on a support, wherein the photosensitive paste film has a light curing depth d, and a photosensitive paste. A photosensitive paste used in such a manner that the film thickness t of the film and the average particle diameter m of the inorganic powder satisfy the following condition: t ≦ d + m. 6. The photosensitive paste according to claim 5, wherein a cross-sectional shape in a direction orthogonal to the longitudinal direction is used to form a rectangular thick film pattern. 7. An electronic component, wherein an electrode is formed using the photosensitive paste according to claim 5. 8. Use of the photosensitive paste according to claim 6 to
An electronic component, wherein an electrode having a rectangular cross section in a direction perpendicular to the longitudinal direction is formed.