WO2019116874A1

WO2019116874A1 - Photosensitive composition and use of same

Info

Publication number: WO2019116874A1
Application number: PCT/JP2018/043421
Authority: WO
Inventors: 佑一朗佐合; 重治高田
Original assignee: 株式会社ノリタケカンパニーリミテド
Priority date: 2017-12-14
Filing date: 2018-11-26
Publication date: 2019-06-20
Also published as: TW201932980A; CN111465899A; KR102579847B1; TWI780277B; CN111465899B; KR20200097774A; JP6646643B2; JP2019105792A

Abstract

The present invention provides a photosensitive composition which contains a conductive powder and a photosensitive organic component. The conductive powder has a D50 particle diameter of 1-5 μm on the volume basis as determined by a laser diffraction/scattering method; and the total of (1) a first conductive powder that has an organic component amount of 0.1% by mass or less as determined by thermogravimetric analysis and (2) a second conductive powder that has an organic component amount of at least 0.5% by mass as determined by thermogravimetric analysis, while having a surface to which a benzotriazole compound adheres, accounts for 90% by mass or more if the whole conductive powder is taken as 100% by mass.

Description

Photosensitive composition and use thereof

The present invention relates to photosensitive compositions and their use.
This application claims priority based on Japanese Patent Application No. 2017-239464 filed on Dec. 14, 2017, the entire contents of which are incorporated herein by reference. It is done.

In the manufacture of electronic parts such as inductors, there is known a method of forming a conductive layer by a so-called photolithography method using a photosensitive composition containing a conductive powder and a photosensitive organic component (for example, Patent Document 1) See 5). In such a method, first, the photosensitive composition is applied onto a substrate by a printing method or the like and dried to form a film-like body. Next, a photomask having a predetermined opening pattern is placed on the molded film-like body, and the film-like body is exposed to light through the photomask. By this, the exposed film-like body portion is photocured. Next, the uncured film-like material portion shielded by the photomask is removed by corrosion cleaning with an etching solution. Then, by baking this, a conductive layer patterned in a desired shape is formed (baked). According to such a method, a conductive layer having a finer pattern can be formed as compared to the case of using various conventional printing methods.

Japanese Patent No. 5163687 International publication 2015/122345 brochure Japanese Patent Application Publication 2016-138310 Japanese Patent No. 5352768 Japanese Patent Application Publication No. 2006-193795

By the way, in recent years, with the rapid miniaturization and high performance of various electronic devices, further miniaturization and densification of electronic components mounted on the electronic devices are required. Along with this, in the manufacture of electronic components, thinning (narrowing) as well as lowering the resistance of the conductive layer is required. For example, it is required to form a fine line conductive layer having a width (line width) of a wiring forming the conductive layer of 30 μm or less, and further, 20 μm or less.

However, according to studies by the present inventors, it has been difficult to form the conductive layer with high resolution when using a photosensitive composition as described in the above-mentioned patent documents. As an example, it has been difficult to stably form a thin line-like wiring because the line width is thickened. In addition, as another example, when forming a wiring pattern, as shown in the schematic view of FIG. 2, a residue (hereinafter referred to as “inter-line”) which could not be completely removed by etching in a gap portion (space) between adjacent wires. "Residue") sometimes remained in spots. As a result, leakage current may occur due to the tunnel effect, or wiring may be connected to cause a short failure.

This invention is made in view of this point, The objective is to provide the photosensitive composition which can form the conductive layer of a fine line with few line residue with high resolution. Another related objective is to provide a composite provided with a conductive film consisting of a dried product of such a photosensitive composition. In addition, another related object is to provide an electronic component provided with a conductive layer formed of a fired body of such a photosensitive composition, and a method of manufacturing the same.

The present invention provides a photosensitive composition comprising a conductive powder and a photosensitive organic component. The conductive powder is a D ₅₀ particle size based on volume based on the laser diffraction scattering method is 1μm or 5μm or less, and, following two types: (1) an organic component amount based on thermogravimetric analysis 0.1 The first conductive powder having a mass% or less; (2) a second electroconductive powder having a benzotriazole-based compound adhering to the surface and having an organic component amount of at least 0.5 mass% based on thermogravimetric analysis The total of the components of; occupies 90% by mass or more, based on 100% by mass of the entire conductive powder.

In the photosensitive composition, the first conductive powder and the second conductive powder having different amounts of organic components are mixed in the conductive powder, and the total of the first conductive powder and the second conductive powder is conductive. It occupies 90% by mass or more of the whole powder. As described above, by using the first conductive powder and the second conductive powder in combination, the conductive layer of the fine line can be stably formed, for example, as compared with the case where each of them is used alone. In addition, since the second conductive powder contains the benzotriazole-based compound, it is difficult for the residue between the lines to remain, and a space can be stably secured between the wirings. Therefore, it is possible to reduce the leakage current and to suppress the occurrence of short circuit failure. The above effects combine to form a conductive layer with high resolution.

In a preferred embodiment disclosed herein, the conductive powder comprises silver-based particles. By this, the conductive layer excellent in the balance of cost and low resistance can be realized.

In a preferred embodiment disclosed herein, the mass ratio of the first conductive powder to the second conductive powder is: first conductive powder: second conductive powder = 85: 15 to 20:80 . By this, the effects of the technology disclosed herein can be exhibited at a higher level. For example, even a conductive layer which has been further refined to be fine-lined can be formed with high accuracy.

In a preferred embodiment disclosed herein, the first conductive powder is a core-shell particle including a metal material as a core and a ceramic material covering at least a part of the surface of the core. By this, the stability of the conductive powder in the photosensitive composition can be further improved, and a highly durable conductive layer can be realized. Further, for example, in applications where a conductive layer is formed on a ceramic base to produce a ceramic electronic component, the integrity with the ceramic base can be enhanced.

In a preferred embodiment disclosed herein, the lightness L ^* of the conductive powder is 50 or more in the L ^* a ^* b ^* color system based on JIS Z 8781: 2013. By this, light can be stably delivered to the deep part of the uncured conductive film at the time of exposure, and a thick film conductive layer can be stably realized.

A preferred embodiment disclosed herein further comprises an organic solvent having a boiling point of 150 ° C. or more and 250 ° C. or less. This can improve the storage stability of the photosensitive composition and the handleability at the time of forming the conductive film, and can suppress the drying temperature after printing to a low level.

Further, according to the present invention, there is provided a composite comprising a green sheet and a conductive film disposed on the green sheet and comprising a dried body of the photosensitive composition.

Further, according to the present invention, there is provided an electronic component comprising a conductive layer comprising a fired body of the photosensitive composition. According to the photosensitive composition, it is possible to stably realize a fine line conductive layer with few interline residues. For this reason, the electronic component provided with the small and / or high-density conductive layer can be realized suitably.

Further, according to the present invention, the photosensitive composition is applied onto a substrate, subjected to photocuring and etching, and then fired to form a conductive layer comprising a fired body of the photosensitive composition. A method of manufacturing an electronic component is provided. According to such a manufacturing method, it is possible to preferably manufacture an electronic component provided with a small and / or high density conductive layer.

FIG. 1 is a cross-sectional view schematically showing a structure of a multilayer chip inductor according to an embodiment. FIG. 2 is a schematic view for explaining the interline residue.

Hereinafter, preferred embodiments of the present invention will be described. In addition, matters other than the matters particularly mentioned in the specification (for example, the conductive powder contained in the photosensitive composition) and matters necessary for the practice of the present invention (for example, the method for preparing the photosensitive composition, the conduction A method of forming a film or a conductive layer, a method of manufacturing an electronic component, etc.) can be understood based on the technical contents taught by the present specification and general technical common knowledge of those skilled in the art. The present invention can be implemented based on the contents disclosed in the present specification and common technical knowledge in the field.

In the following description, a film-like body (dried matter) obtained by drying the conductive composition at a temperature (generally 200 ° C. or less, eg 100 ° C. or less) equal to or lower than the boiling point of the benzotriazole compound is referred to as “conductive film”. The conductive film includes all unfired (before firing) film-like materials. The conductive film may be an uncured product before light curing or a cured product after light curing. In the following description, a sintered body (baked product) obtained by firing the conductive composition at a temperature equal to or higher than the sintering temperature of the conductive powder is referred to as a “conductive layer”. The conductive layer includes a wiring (linear body), a wiring pattern, and a solid pattern. Further, the notation “A to B” indicating the range in the present specification means A or more and B or less.

«Photosensitive composition»
The photosensitive composition disclosed herein contains a conductive powder and a photosensitive organic component as essential components. Hereinafter, each component will be described in order.

<Conductive powder>
The conductive powder is a component that imparts electrical conductivity to the conductive layer obtained by firing the photosensitive composition. In the technology disclosed herein, the conductive powder is a mixed powder including at least a first conductive powder and a second conductive powder. And the sum total of the 1st electric conduction powder and the 2nd electric conduction powder occupies 90 mass% or more, when the whole electric conduction powder is made into 100 mass%. As a result, the fine line conductive layer can be formed with high resolution.

The conductive powder may be composed of the first conductive powder and the second conductive powder, or may contain other conductive powders. From the viewpoint of exhibiting the effects of the technology disclosed herein at a higher level, the total of the first conductive powder and the second conductive powder is preferably 95% by mass or more of the entire conductive powder, It is more preferable that it is 98 mass% or more.

The first conductive powder is a conductive powder in which the amount of organic components is kept low. The organic component contained in the conductive powder is mainly derived from the organic surface coating agent adhering to the surface of the conductive powder and the residual organic component used in the production of the conductive powder, such as an organic solvent. The organic surface coating agent will be described in detail in the section of the second conductive powder described later.

In the technology disclosed herein, the first conductive powder has an organic component amount of 0.1% by mass or less. The first conductive powder is not particularly limited except that the amount of the organic component is 0.1% by mass or less. By including the first conductive powder in which the amount of the organic component is thus suppressed in the conductive powder, the etching resistance of the conductive film can be improved, and the cured conductive film portion is also suitable after the etching process. On the substrate. Therefore, peeling of the conductive film or thinning of the wiring can be suppressed. From the above viewpoint, the amount of the organic component of the first conductive powder may be, for example, 0.08% by mass or less.

The first conductive powder may or may not contain the organic component intentionally or unavoidably (it may be below the lower limit of detection). The amount of the organic component of the first conductive powder may be approximately 0.01% by mass or more, for example, 0.03% by mass or more. In other words, the first conductive powder may have an organic surface coating attached to the surface, or may contain a residual solvent. When the first conductive powder contains an organic surface coating agent, it preferably contains the same organic surface coating agent as the second conductive powder. For example, it is preferable to include a benzotriazole-based compound.

In addition, in this specification, "the amount of organic components" means the mass attenuation factor measured by the following measuring method. That is, first, a predetermined amount of conductive powder is weighed as a measurement sample, and the measurement sample is measured at a temperature rising rate of 10 ° C./minute in an air atmosphere using a thermogravimetric measurement device (TG) at room temperature. Heat from (25 ° C.) to 600 ° C. And the mass change (mass decay before and after heating) according to the following formula: amount of organic component (%) = [(mass before heating) − (mass after heating to 600 ° C.)] / (Mass before heating) × 100; Calculate the rate) The mass attenuation factor determined in this manner is called the amount of organic component. A unit is mass%.

The second conductive powder is a conductive powder in which the amount of the organic component is higher than that of the first conductive powder. In the technology disclosed herein, the benzotriazole-based compound is attached to the surface of the second conductive powder. The benzotriazole compound is an organic surface coating agent. The second conductive powder has an organic component amount of at least 0.5% by mass. The second conductive powder is not particularly limited except that the benzotriazole-based compound is attached to the surface and the amount of the organic component is at least 0.5% by mass. By including such a second conductive powder in the conductive powder, the releasability of the uncured portion can be improved during the etching process, and the wiring can be prevented from becoming too thick. In addition, inter-line residue is less likely to remain in the space between the wires, and a stable space can be secured between the wires. Therefore, it is possible to reduce the leakage current and to suppress the occurrence of short circuit failure.

From the above viewpoint, the amount of the organic component of the second conductive powder is preferably 0.7% by mass or more, preferably 0.75% by mass or more, and for example, 0.8% by mass or more. It is also good. Further, although not particularly limited, the upper limit of the amount of the organic component of the second conductive powder is about 2% by mass or less in view of the range of the amount of the organic component of the commercially available conductive powder. The upper limit of the amount of the organic component of the second conductive powder is preferably 1.5% by mass or less, and more preferably 1% by mass or less, from the viewpoint of densification and resistance reduction of the conductive layer.

The benzotriazole-based compound adhering to the surface of the second conductive powder is an organic surface coating agent that improves the stability and storage stability of the conductive powder. The benzotriazole-based compound may be a compound having a benzotriazole skeleton. As one preferable example, a compound having one or more structural parts of 1H-benzotriazole represented by the following (1) or a structural part of 2H-benzotriazole which is a tautomer thereof can be mentioned .

Specific examples of the benzotriazole compound include 1H-benzotriazole, 2H-benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'- Di-t-butylphenyl) benzotriazole, 2- (2′-hydroxy-4′-n-octoxyphenyl) benzotriazole, 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole, 2 -(2'-hydroxy-3 ', 5'-di-t-amylphenyl) benzotriazole, 2-hydroxy-4- (2-hydroxy-3-methacryloxy) propoxybenzophenone, 2- (2'-hydroxy-3 '-T-Butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydro) Ci-3'-t-Butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, etc. Can be mentioned. Among them, those which do not contain a halogen element (for example, fluorine or chlorine) are preferable.

The organic component contained in the second conductive powder typically contains a benzotriazole-based compound as a main component (component that occupies 50 mol% or more in molar ratio). The organic component of the second conductive powder is preferably such that the benzotriazole-based compound accounts for 80 mol% or more, and it is further preferable that the organic component be composed of the benzotriazole-based compound. It is known that the second conductive powder can be used as an organic surface coating agent, in addition to the benzotriazole-based compound, intentionally or unavoidably, as long as the effects of the technology disclosed herein are not significantly impaired. May further comprise other organic surface coatings. For example, when the total amount of organic components of the second conductive powder is 100 mol%, the amount of the other organic surface coating agent is approximately less than 50 mol%, preferably 10 mol% or less, in addition to the benzotriazole compound More preferably, it may be contained in a proportion of 5 mol% or less. It is more preferable that the second conductive powder does not contain a fatty acid such as a carboxylic acid as an organic surface coating agent. By this, the effects of the technology disclosed herein can be exhibited at a higher level. The fact that the organic surface coating agent contains a benzotriazole-based compound can be confirmed, for example, by gas chromatography-mass spectrometry (GC-MS).

Although not particularly limited, the mass ratio of the first conductive powder to the second conductive powder is approximately 95: 5 to 5:95, typically 90:10 to 10:90, preferably 85. The ratio is preferably from 15 to 20:80, more preferably from 60:40 to 20:80, and particularly preferably from 60:40 to 40:60. By this, the effects of the technology disclosed herein can be exhibited at a higher level. For example, even a conductive layer which has been further refined to be fine-lined can be formed with high resolution and accuracy. In addition, by containing the first conductive powder at a ratio of a predetermined value or more, the ratio of components that can be burned out at the time of firing can be reduced, and a conductive layer having high density and low resistance can be suitably realized.

The types of the first conductive powder and the second conductive powder are not particularly limited. As a 1st electroconductive powder and a 2nd electroconductive powder, 1 type, or 2 or more types can be suitably selected and used among conventionally well-known things according to a use etc., respectively. As one preferred example, gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), aluminum (Al), nickel (Ni), ruthenium (Ru), rhodium (Rh), Examples include simple metals such as tungsten (W), iridium (Ir) and osmium (Os), and mixtures and alloys thereof. Examples of the alloy include silver alloys such as silver-palladium (Ag-Pd), silver-platinum (Ag-Pt), silver-copper (Ag-Cu) and the like.

In a preferred embodiment, the first conductive powder and / or the second conductive powder contains silver-based particles. Silver is relatively inexpensive and has high electrical conductivity. For this reason, the conductive layer excellent in the balance of cost and low resistance is realizable by including silver system particles. The silver-based particles may be those containing a silver component. As an example, silver alone, the above-described silver alloy, core-shell particles having silver-based particles as a core, and the like can be mentioned.

In another preferred aspect, the first conductive powder and / or the second conductive powder comprises metal-ceramic core-shell particles. The metal-ceramic core-shell particle has a core portion containing a metal material, and a coating portion covering at least a part of the surface of the core portion and containing a ceramic material. Ceramic materials are excellent in chemical stability, heat resistance and durability. Therefore, by adopting the form of metal-ceramic core-shell particles, the stability of the conductive powder in the photosensitive composition can be further improved, and a highly durable conductive layer can be realized. For example, in applications where a conductive layer is formed on a ceramic base to produce a ceramic electronic component, the inclusion of metal-ceramic core-shell particles can enhance the integrity with the ceramic base. Peeling or disconnection of the conductive layer after firing can be suitably suppressed.

Among them, the first conductive powder having a small amount of organic component preferably contains metal-ceramic core-shell particles, and more preferably the first conductive powder is composed of metal-ceramic core-shell particles. The first conductive powder having a small amount of the organic component tends to have relatively low stability and storage stability in the conductive composition as compared to the second conductive powder having a large amount of the organic component. When the first conductive powder contains metal-ceramic core-shell particles, it is possible to compensate for the low amount of organic components and to improve the stability and storage stability of the entire conductive composition.

In the metal-ceramic core-shell particles, examples of the metal material constituting the core portion include the above-described metals alone, and mixtures and alloys thereof. Among them, silver-based particles are preferable for the reasons described above. In other words, it is preferable that the first conductive powder and / or the second conductive powder include silver-ceramic core-shell particles.

Although not particularly limited, examples of the ceramic material constituting the metal-ceramic coating portion include zirconium oxide (zirconia), magnesium oxide (magnesia), aluminum oxide (alumina), silicon oxide (silica), oxide Oxide materials such as titanium (titania), cerium oxide (ceria), yttrium oxide (yttria) and barium titanate; Complex oxides such as cordierite, mullite, forsterite, steatite, sialon, zircon and ferrite Materials: Nitride-based materials such as silicon nitride (silicon nitride) and aluminum nitride (aluminum nitride); Carbide-based materials such as silicon carbide (silicon carbide); Hydroxide-based materials such as hydroxyapatite; . For example, in applications where a conductive layer is formed on a ceramic base to produce a ceramic electronic component, a ceramic material that is the same as or superior in affinity to the ceramic base is preferable.

Although not particularly limited, the content ratio of the ceramic material may be, for example, 0.01 to 5.0 parts by mass with respect to 100 parts by mass of the metal material of the core portion. The metal-ceramic core-shell particles can be produced by a conventionally known method. For example, as described in paragraphs 0025 to 0028 of Japanese Patent No. 5075222, which is the prior application of the present applicant, a metal material and an organic metal compound having a target metal element (for example, metal alkoxide or chelate compound) or It can be produced by reacting an oxide sol.

Conductive powder, the balance with exposure _{performance, D 50} particle size is 1 ~ 5 [mu] m. D ₅₀ particle size within the above range, to improve the exposure performance of the uncured conductive film, the conductive layer of the fine line can be stably formed. The first conductive powder and the second conductive powder, respectively, may D ₅₀ particle size is in the above range. Of from the viewpoint of improving the stability aggregating by suppressing conductive composition of the conductive powder, D ₅₀ particle size of the conductive powder is, for example, 1.5 [mu] m or more, may be 2.0μm or more. The D ₅₀ particle diameter of the conductive powder may be, for example, 4.5 μm or less and 4.0 μm or less from the viewpoint of promoting fine line formation, densification, and resistance reduction of the conductive layer. In the present specification, “D ₅₀ particle size” refers to a particle size corresponding to an integrated value of 50% from the side of smaller particle size in the volume-based particle size distribution based on the laser diffraction / scattering method.

Although not particularly limited, the D ₅₀ particle size of the first conductive powder and the second conductive powder is at least 0.5 μm, typically 0.5 to 3.0 μm, for example 1.0 to It is preferable that they be separated by about 2.0 μm. In other words, the particle size distribution of the entire conductive powder is preferably multimodal. In one embodiment, the D ₅₀ particle size of the first conductive powder having a small amount of organic component is in the range of about 3 to 5 μm, for example 3.5 to 4.5 μm, and the second conductive powder has a large amount of organic component The D ₅₀ particle size of H 2 should be approximately in the range of 1 to 3.5 μm, for example 1.5 to 3 μm. Thus, as compared with the case the difference between the D ₅₀ particle size of the first conductive powder and the second conductive powder is small, to improve the denseness and filling properties of the conductive layer. As a result, resistance reduction of the conductive layer can be suitably enhanced.

Although the shape of the conductive particles constituting the conductive powder is not particularly limited, the shape of the conductive particles is typically substantially spherical, preferably 1 to 2 in average aspect ratio (major axis / minor axis ratio). It has a spherical shape of 1.5, for example, 1 to 1.2. By this, the exposure performance can be realized more stably. Each of the first conductive powder and the second conductive powder may have an average aspect ratio in the above range. In the present specification, “average aspect ratio” refers to an arithmetic average value of aspect ratios calculated from observed images obtained by observing a plurality of conductive particles with an electron microscope. Further, in the present specification, "spherical" indicates that the shape is generally regarded as a sphere (ball), and is a term that may include an elliptical shape, a polygonal shape, a disc spherical shape, and the like.

Although not particularly limited, it is preferable that the whole of the conductive powder have a lightness L ^* of 50 or more in the L ^* a ^* b ^* color system based on JIS Z 8781: 2013. By this, the irradiation light can stably reach the deep part of the uncured conductive film at the time of exposure, and for example, a conductive layer having a thickness of 5 μm or more, or even 10 μm or more can be stably realized. can do. From the above viewpoint, the lightness L ^* of the conductive powder may be approximately 55 or more, for example 60 or more. Lightness L ^* can be adjusted for example by the type and D ₅₀ particle size of the conductive powder mentioned above. The measurement of the lightness L ^* can be performed, for example, with a spectrocolorimeter conforming to JIS Z 8722: 2009.

Although not particularly limited, the proportion of the conductive powder in the entire photosensitive composition may be about 50% by mass or more, typically 60 to 95% by mass, for example 70 to 90% by mass. By satisfying the above range, a conductive layer with high density and high electrical conductivity can be formed. Moreover, the handling property of the photosensitive composition and the workability at the time of forming the conductive film can be improved.

<Photosensitive organic component>
The photosensitive organic component is a component that imparts photocurability to the conductive film. The photosensitive organic component is a component having a property of being cured by irradiation of light energy such as ultraviolet light. In the present specification, the "photosensitive organic component" refers to all of photopolymerizable or photomodified organic compounds. As one preferred example, a mixture containing a photosensitive resin having an unsaturated bond and a photopolymerization initiator for generating an active species; a so-called diazo resin (for example, a condensate of an aromatic bis azide and formaldehyde); an epoxy compound Etc., and a photoacid generator such as a diallyl iodonium salt; a naphthoquinone diazide compound; and the like. Among them, a mixture containing a photosensitive resin and a photopolymerization initiator is preferable from the viewpoint of stability and the like.

The photosensitive resin is a component that is polymerized and cured by active species generated by decomposition of the photopolymerization initiator. The polymerization reaction may be addition polymerization or ring opening polymerization. Photosensitive resins include monomers, polymers and oligomers having one or more unsaturated bonds and / or cyclic structures. As photosensitive resin, 1 type, or 2 or more types can be suitably selected and used among conventionally well-known things according to a use, the kind of base material, etc. One preferable example is a radically polymerizable monomer having one or more radically polymerizable reactive groups such as (meth) acryloyl group and vinyl group. Among them, (meth) acrylate monomers having a (meth) acryloyl group are preferable. By including the (meth) acrylate monomer, the flexibility of the conductive layer and the followability to the substrate can be improved. As a result, the occurrence of defects such as peeling and disconnection can be suppressed at a still higher level. In the present specification, "(meth) acryloyl" is a term including "methacryloyl" and "acryloyl", and "(meth) acrylate" is a term including "methacrylate" and "acrylate".

(Meth) acrylate monomers include monofunctional (meth) acrylates having one functional group per molecule, multifunctional (meth) acrylates having two or more functional groups per molecule, and modified products thereof Do. Specific examples of (meth) acrylate monomers include triethylene glycol monoacrylate, triethylene glycol monomethacrylate, tetraethylene glycol monoacrylate, tetraethylene glycol monomethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol pentaacrylate, Examples thereof include polyfunctional (meth) acrylates such as dipentaerythritol hexaacrylate, and urethane (meth) acrylates having a urethane bond (—NH—C (= O) —O—). Among them, it is preferable that the (meth) acrylate monomer contains a urethane (meth) acrylate. As a result, the etching resistance of the exposed portion can be further improved, and the stretchability and flexibility of the conductive film can be further improved. Therefore, the integrity with the substrate can be enhanced. Moreover, from a viewpoint of improving photocurability, the (meth) acrylate monomer has a preferable monomer which has five or more (meth) acryloyl groups per molecule. The proportion of urethane (meth) acrylate in the entire photosensitive resin is preferably 30% by volume or more, for example 50% by volume or more, on a volume basis.

The photopolymerization initiator is a component which is decomposed by irradiation with light such as ultraviolet rays to generate active species such as radicals and cations, and to start the polymerization reaction of the photosensitive resin. As a photoinitiator, 1 type, or 2 or more types can be suitably selected and used among conventionally well-known things according to the kind etc. of photosensitive resin. As one preferred example, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butane -1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethyl benzoyl diphenyl phosphine oxide, 2,4-diethyl thioxanthone, benzophenone and the like.

Although not particularly limited, the proportion of the photosensitive organic compound in the entire photosensitive composition is generally 0.1 to 25% by mass, typically 0.5 to 20% by mass, for example 1 to 15% by mass. It may be%. Further, the content ratio of the photosensitive resin may be, for example, 0.1 to 30 parts by mass with respect to 100 parts by mass of the conductive powder. Further, the content ratio of the photopolymerization initiator may be approximately 0.001 to 100 parts by mass, for example, 0.01 to 10 parts by mass, with respect to 100 parts by mass of the photosensitive resin.

<Organic dispersion medium>
The photosensitive composition may contain, in addition to the above-described essential components, an organic dispersion medium in which these are dispersed. The organic dispersion medium is a component that imparts appropriate viscosity and fluidity to the photosensitive composition to improve the handleability of the photosensitive composition or to improve the workability at the time of forming the conductive film. is there. As the organic dispersion medium, it is possible to appropriately select and use one kind or two or more kinds out of conventionally known ones according to the kind of photosensitive organic compound and the like. As one preferred example, alcohol solvents such as terpineol, dihydroterpineol (mentanol), texanol, 3-methyl-3-methoxybutanol, benzyl alcohol and the like; glycol solvents such as ethylene glycol, propylene glycol and diethylene glycol; dipropylene glycol methyl ether Ether solvents such as methyl cellosolve (ethylene glycol monomethyl ether), cellosolve (ethylene glycol monoethyl ether) and butyl carbitol (diethylene glycol monobutyl ether); diethylene glycol monobutyl ether acetate, dipropylene glycol methyl ether acetate, butyl glycol acetate, butyl Diglycol acetate, butyl cellosolve acetate, butyl carbonate Bi Tall acetate (diethylene glycol monobutyl ether acetate), ester solvents such as isobornyl acetate; mineral spirits; toluene, xylene, naphtha, hydrocarbon solvents such as petroleum hydrocarbon organic solvent and the like.

Among them, from the viewpoint of improving the storage stability of the photosensitive composition and the handleability at the time of forming a conductive film, an organic solvent having a boiling point of 150 ° C. or more, more preferably 170 ° C. or more is preferable. In addition, as another preferred example, an organic solvent having a boiling point of 250 ° C. or less, and further an organic solvent having a boiling point of 220 ° C. or less are preferable from the viewpoint of suppressing the drying temperature after printing the conductive film. This can improve productivity and reduce production costs.

In addition, for example, in applications where a conductive layer is formed on a ceramic base to produce a ceramic electronic component, an organic solvent having low permeability to a ceramic green sheet is preferable. Examples of the organic solvent having low permeability to the ceramic green sheet include an organic solvent having a sterically bulky structure such as a cyclohexyl group and a tert-butyl group, and an organic solvent having a relatively large molecular weight. Furthermore, for example, an organic solvent having low permeability to the ceramic green sheet as described above, and an organic solvent capable of suitably dissolving a component (for example, a photosensitive organic component) contained in the photosensitive composition may be any ratio. It is also preferable to mix and use as an organic dispersion medium.

Examples of the organic solvent having the above-mentioned properties (boiling point and permeability to ceramic green sheet) include Dowanol DPM (trademark) (boiling point: 190 ° C, manufactured by Dow Chemical Company), Dowanol DPMA (trademark) Boiling point: 209 ° C, manufactured by Dow Chemical Company, Menthanol (boiling point: 207 ° C), Menthanol P (boiling point: 216 ° C), Isopar H (boiling point: 176 ° C, Kanto Fuel Co., Ltd.), SW-1800 (boiling point) 198 ° C., manufactured by Maruzen Oil Co., Ltd.) and the like.

When the photosensitive composition contains an organic dispersion medium, it is not particularly limited, but the ratio of the organic dispersion medium to the entire photosensitive composition is generally 1 to 50% by mass, typically 3 to It may be 30% by mass, for example 5 to 20% by mass.

<Organic binder>
The photosensitive composition may contain an organic binder in addition to the above-described essential components. The organic binder is a component that enhances the adhesion between the uncured conductive film and the substrate. As the organic binder, it is possible to appropriately select and use one or two or more from conventionally known ones in accordance with the type of photosensitive organic compound, base material, and the like. As one preferable example, cellulose polymers such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose and hydroxymethyl cellulose, acrylic resin, phenol resin, alkyd resin, polyvinyl alcohol, polyvinyl butyral and the like can be mentioned. Among them, when an alkaline aqueous solution is used for etching, a hydroxyl group (-OH), a carboxyl group (-C (= O) OH), an ester bond (-C (= O) O-), a sulfo group ( Compounds having a structural moiety exhibiting acidity, such as —SO ₃ H), are preferred. Further, from the viewpoint of easy removal by etching, hydrophilic organic binders such as cellulose polymers and acrylic resins are preferable.

<Other ingredients>
In addition to the above-described essential components, various additional components can be added to the photosensitive composition as needed, as long as the effects of the technology disclosed herein are not significantly impaired. As the additive component, one or two or more can be appropriately selected and used from conventionally known ones. Examples of the additive components include, for example, inorganic fillers, photosensitizers, polymerization inhibitors, radical scavengers, antioxidants, light absorbers, ultraviolet absorbers, plasticizers, surfactants, leveling agents, thickeners And dispersants, antifoaming agents, antigelling agents, stabilizers, antioxidants, preservatives, colorants, pigments and the like. Although not particularly limited, the proportion of the additive component in the entire photosensitive composition may be about 5% by mass or less, for example, 3% by mass or less.

<Application of Photosensitive Composition>
According to the photosensitive composition disclosed herein, it is possible to increase the conductive layer of fine lines with less line residue and, for example, a line width smaller than 30 μm, and further a line width smaller than 20 μm. It can be stably formed at resolution. In addition, peeling or disconnection of the conductive layer can be reduced. In addition, it is possible to reduce the leakage current and to suppress the occurrence of short circuit failure. Therefore, the photosensitive composition disclosed herein can be suitably used to form a conductive layer in various electronic components such as, for example, an inductance component, a capacitor component, and a multilayer circuit board.

The electronic component may be of various mounting forms such as a surface mounting type or a through hole mounting type. The electronic component may be a laminate type, a winding type, or a thin film type. Typical examples of the inductance component include high frequency filters, common mode filters, inductors (coils) for high frequency circuits, inductors for general circuits (coils), high frequency filters, choke coils, transformers and the like.

In addition, a photosensitive composition in which the conductive powder contains metal-ceramic core-shell particles can be suitably used for forming a conductive layer of a ceramic electronic component. In the present specification, the term "ceramic electronic component" includes all electronic components having an amorphous ceramic substrate (glass ceramic substrate) or a crystalline (i.e. non-glass) ceramic substrate. Typical examples are a high frequency filter having a ceramic base, a ceramic inductor (coil), a ceramic capacitor, a low temperature co-fired ceramic substrate (LTCC base), a high temperature co-fired multilayer ceramic base (a low temperature co-fired ceramic substrate). High Temperature Co-fired Ceramics Substrate (HTCC base material) and the like.

FIG. 1 is a cross-sectional view schematically showing the structure of the multilayer chip inductor 1. The dimensional relationships (length, width, thickness, etc.) in FIG. 1 do not necessarily reflect the actual dimensional relationships. Further, reference signs X and Y in the drawings respectively indicate the left and right direction and the up and down direction. However, this is only for convenience of explanation.

The multilayer chip inductor 1 includes a main body portion 10 and external electrodes 20 provided on both side surface portions in the left-right direction X of the main body portion 10. The shape of the multilayer chip inductor 1 is, for example, a size such as 1608 shape (1.6 mm × 0.8 mm), 2520 shape (2.5 mm × 2.0 mm) or the like.

The main body portion 10 has a structure in which the ceramic layer (dielectric layer) 12 and the internal electrode layer 14 are integrated. The ceramic layer 12 is made of, for example, a ceramic material as described above, which can constitute the coating portion of the conductive powder. In the vertical direction Y, the internal electrode layer 14 is disposed between the ceramic layers 12. The internal electrode layer 14 is formed using the above-described photosensitive composition. The internal electrode layers 14 adjacent to each other in the vertical direction Y with the ceramic layer 12 interposed therebetween are conducted through the vias 16 provided in the ceramic layer 12. As a result, the internal electrode layer 14 is configured in a three-dimensional spiral shape (helical shape). Both ends of the internal electrode layer 14 are connected to the external electrode 20, respectively.

Such a laminated chip inductor 1 can be manufactured, for example, according to the following procedure. That is, first, a paste containing a ceramic material as a raw material, a binder resin and an organic solvent is prepared, and this is supplied onto a carrier sheet to form a ceramic green sheet. Then, the ceramic green sheet is rolled and cut into a desired size to obtain a plurality of green sheets for forming a ceramic layer. Next, via holes are appropriately formed at predetermined positions of the plurality of ceramic layer forming green sheets using a drilling machine or the like.

Then, using the photosensitive composition described above, conductive films of a predetermined coil pattern are formed at predetermined positions of the plurality of green sheets for forming a ceramic layer. As an example, the following steps: (Step S1) a step of forming a film-like body consisting of a dried product of the photosensitive composition by applying the photosensitive composition on a green sheet for forming a ceramic layer and drying; Step S2) A step of covering a film-like body with a photomask of a predetermined opening pattern, exposing through a photomask, and partially curing the film-like body: (Step S3) Etching the film-like body after photo curing A non-fired conductive film can be formed by a manufacturing method including the step of: removing the uncured portion.

In addition, in forming a conductive film using the said photosensitive composition, the conventionally well-known method can be used suitably. For example, in (Step S1), application of the photosensitive composition can be performed using various printing methods such as screen printing, a bar coater, or the like. Drying of the photosensitive composition may typically be performed at 50 to 100.degree. In (Step S2), for example, an exposure unit which emits a light beam in a wavelength range of 10 to 400 nm, for example, an ultraviolet irradiation lamp such as a high pressure mercury lamp, a metal halide lamp, or a xenon lamp can be used. In (Step S3), for example, an aqueous solution containing an alkali component such as sodium hydroxide or sodium carbonate can be used for the etching.

Next, a plurality of green sheets for forming a ceramic layer in which the unfired conductive film is formed are stacked and pressure-bonded. This produces a laminate of unfired ceramic green sheets. Then, the laminate of the ceramic green sheets is fired, for example, at 600 to 1000.degree. As a result, the ceramic green sheet is integrally sintered to form the main body portion 10 including the ceramic layer 12 and the internal electrode layer 14 made of a fired body of the photosensitive composition. Then, an appropriate external electrode forming paste is applied to both end portions of the main body portion 10 and baked to form the external electrode 20. As described above, the multilayer chip inductor 1 can be manufactured.

The following examples illustrate some of the embodiments of the present invention, but are not intended to limit the present invention to those shown.

(Preparation of silver powder)
First, seven commercially available silver powders (silver powders a to g) were prepared. Incidentally, all of these silver powders have a lightness L ^* of 50 to 80 in an L ^* a ^* b ^* color system based on JIS Z 8781: 2013.
In addition, silver powder h was prepared using silver powder a. Specifically, first, zirconium butoxide was added to methanol to prepare a coating solution. Next, silver powder a was added to the coating solution and stirred for 1 hour. Next, the solid content was recovered from the coating solution and dried at 100 ° C. As a result, a silver powder (silver-zirconia core-shell particles) surface-coated with an amount of 0.5 parts by mass converted to zirconium oxide (ZrO ₂ ) with respect to 100 parts by mass of silver powder was obtained. Thus, silver powder h was prepared.

Next, the amounts of organic components of the silver powders a to h were each measured using the thermogravimetry apparatus under the above-described heating conditions. The results are shown in the column of "amount of organic component" in Tables 1 and 2. In Tables 1 and 2, the type of surface treatment agent detected by gas chromatography-mass spectrometry (GC-MS) and the volume-based D ₅₀ particle size based on laser diffraction / scattering method are combined. Show. In addition, "BTA type" of the column of a surface treatment agent represents a benzotriazole type compound.

(Preparation of photosensitive composition)
First, silver powders and vehicles shown in Tables 1 and 2 were prepared. The vehicle comprises a urethane acrylate monomer as a photosensitive resin, Irgacure 369 (registered trademark) (made by Ciba Specialty Chemicals Inc.) as a photopolymerization initiator, an organic binder, a polymerization inhibitor, and a sensitizer. An antigelling agent and an ultraviolet light absorber were prepared by dissolving in dipropylene glycol methyl ether acetate and dihydroterpineol as organic solvents. Then, photosensitive powders (Examples 1 to 8 and Comparative Examples 1 to 7) were prepared by mixing silver powder and a vehicle at a mass ratio of 77:23.

(Preparation of wiring pattern)
First, using the stainless steel screen, the photosensitive compositions prepared above were each coated on a commercially available ceramic green sheet. Next, this was dried at 60 ° C. for 15 minutes to form a film-like body on a green sheet. Next, a photomask was placed over the film-like body. At this time, as the photomask, a mask having a wiring pattern with a line width of 20 μm and an interval (space) of 20 μm between adjacent lines (a mask of L / S = 20 μm / 20 μm) was used. With the photomask covered, light was irradiated at an intensity of 2500 mJ / cm ² by an exposure machine to partially cure the film-like body. After the exposure, a 0.1% by mass aqueous solution of Na ₂ CO ₃ was sprayed on the ceramic green sheet to etch away the uncured film-like part, and then it was washed with pure water and dried at room temperature. Thus, a wiring pattern (spiral pattern) in which the wiring was arranged in a spiral was produced.

(Evaluation of wiring pattern)
The residue, peeling, and line width were evaluated for the produced wiring patterns, and comprehensive evaluation was performed based on these evaluations.

Evaluation of residue:
The wiring pattern was observed with an electron microscope, and the residue was evaluated from the obtained observation image. The observation image was taken at a magnification of 200 times. Then, the number of interline residue remaining in the space between the wires in the observation image was counted. The interline residue was counted for a plurality of fields of view, and the arithmetic mean value of interline residues in a plurality of fields of view was taken as the “number of interline residues”. The results are shown in the column "Evaluation of residue" in Tables 1 and 2. The notation of the said column is as follows.
"○": The number of interline residues is 0 / field (no interline residues identified)
“△”: number of interline residue is 1 to 3 per field of view “x”: number of interline residue is 4 or more per field of view

Evaluation of peeling:
The presence or absence of peeling and disconnection was confirmed from the said observation image. A result is shown in the column of "evaluation of peeling" of Tables 1 and 2. The notation of the said column is as follows.
"○": no peeling "×": peeling

・ Evaluation of line width:
The line width of the wiring pattern was measured from the observation image. The line width was measured for a plurality of fields of view, and the arithmetic mean value was taken as the line width. The results are shown in the "line width" column of Tables 1 and 2. Moreover, the notation of the column of evaluation is as follows.
"○": 20 to 25 μm (target value)
"△": 25 to 28 μm
"X": 28 μm or more

·Comprehensive evaluation:
"○": In each evaluation of the above-mentioned residue, exfoliation, line width, there is not one x "x": In each evaluation of the above-mentioned residue, exfoliation, line width, there is one or more x

As shown in Table 1, Comparative Example 1 is a test example using only silver powder a having a small amount of organic components. In Comparative Example 1, variation in line width was large in the wiring pattern, and thickening of the line width was confirmed in some places. As a result, the average line width became larger than the target value, making it difficult to form a stable fine line. The reason for this is that the light-scattering property of the conductive film is too high, so that light scattered from the opening of the photomask hardens part of the conductive film in the light-shielding portion, and etching resistance of the conductive film It is considered that the removal of the uncured portion was incomplete during etching because the conductivity was too high. Further, Comparative Example 2 is a test example using only silver powder b having a relatively large amount of organic component. In the comparative example 2, many peeling and disconnection were confirmed by the wiring pattern, and formation of the wiring pattern was difficult. As the reason for this, it is considered that the cured portion has flowed together with the uncured portion during the etching. Further, Comparative Example 3 is a test example using only silver powder e having fatty acid and a benzotriazole compound adhering to the surface. In the comparative example 3, many peeling and disconnection were confirmed by the wiring pattern, and formation of the fine line was difficult. Furthermore, a lot of interline residue remains in the space between the wires.

Examples 1 to 4 are test examples in which silver powder a and silver powder b are used in combination. In Examples 1 to 4, fine line wiring patterns with no line residue and with a line width of 28 μm or less, and further suppressed to 25 μm or less are formed with high resolution compared to Comparative Examples 1 to 3. I was able to. That is, it was possible to form a fine line wiring pattern in which there was no peeling, disconnection or short circuit of the wiring, and a stable space was secured between the wirings.

Table 2 further investigates a mixed system of two or more types of silver powder. Examples 5 and 6 are test examples in which silver powder c or silver powder d is used instead of silver powder b. Example 7 is a test example using silver powder g in addition to silver powder a and silver powder b. Example 8 is a test example using silver powder h in place of silver powder a. As shown in Table 2, in Examples 5 and 6, 7 and 8 as well as Examples 1 to 4, the fine line wiring pattern could be formed with high resolution.

On the other hand, Comparative Examples 4 to 6 are test examples in which silver powders e to g are used instead of silver powder b. The comparative example 7 is a test example which reduced the sum total of silver powder a and silver powder b to 80% of the whole silver powder. In Comparative Examples 4 to 6 and Comparative Example 7, a large amount of interline residue remains in the space between the wires. Moreover, in Comparative Examples 5 and 6, the variation in line width was large in the wiring pattern, and the line width was slightly larger than the target value.

From the above results, the first conductive powder having an organic component content of 0.1% by mass or less based on thermogravimetric analysis, and the benzotriazole compound adhering to the surface, the organic component content based on thermogravimetric analysis is By using the second conductive powder which is at least 0.5% in combination and setting the total of these to a proportion of 90% by mass or more of the entire conductive powder, the fine line wiring pattern with little interline residue can be made high. It turned out that it could be formed in resolution. These results show the significance of the technology disclosed herein.

As mentioned above, although this invention was demonstrated in detail, these are only an illustration and this invention can add a various change in the range which does not deviate from the main point.

Reference Signs List 1 laminated chip inductor 10 main body 12 ceramic layer 14 internal electrode layer 20 external electrode

Claims

Containing conductive powder and photosensitive organic component,
Wherein the conductive powder is, D 50 particle size based on volume based on the laser diffraction scattering method is at 1μm or more 5μm or less, and, following two types:
(1) The first conductive powder, wherein the amount of organic component based on thermogravimetry is 0.1% by mass or less;
(2) A second conductive powder, wherein a benzotriazole-based compound is attached to the surface, and the amount of the organic component based on thermogravimetry is at least 0.5% by mass;
The photosensitive composition which the sum total of the component occupies 90 mass% or more, when the whole of the said electroconductive powder is 100 mass%.
The conductive powder contains silver-based particles,
The photosensitive composition according to claim 1.
The mass ratio of the first conductive powder to the second conductive powder is: first conductive powder: second conductive powder = 85: 15 to 20:80.
The photosensitive composition according to claim 1 or 2.
The first conductive powder is a core-shell particle comprising a metal material as a core and a ceramic material covering at least a part of the surface of the core.
The photosensitive composition according to any one of claims 1 to 3.
In the L * a * b * color system based on JIS Z 8781: 2013, the lightness L * of the conductive powder is 50 or more.
The photosensitive composition according to any one of claims 1 to 4.
It further includes an organic solvent having a boiling point of 150 ° C. or more and 250 ° C. or less,
The photosensitive composition according to any one of claims 1 to 5.
A composite, comprising: a green sheet; and a conductive film disposed on the green sheet, the conductive film comprising the dried body of the photosensitive composition according to any one of claims 1 to 6.
An electronic component comprising a conductive layer comprising the fired body of the photosensitive composition according to any one of claims 1 to 6.
A photosensitive composition according to any one of claims 1 to 6 is applied to a substrate, subjected to photocuring and etching, and then fired to form a fired body of the photosensitive composition. A method of manufacturing an electronic component, comprising the step of forming a conductive layer.