TW201937287A - Photosensitive composition and use thereof - Google Patents

Abstract

The present invention discloses a photosensitive composition containing a conductive powder, a photopolymerizable compound, and a photopolymerization initiator. The photopolymerization initiator contains at least two components: (1) 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide; and (2) an [alpha]-aminoalkylphenone. The 2,4,6-Trimethylbenzoyl-diphenyl-phosphine oxide occupies 50% by mass relative to 100% by mass of the photopolymerization initiator.

Description

Photosensitive composition and application

The present invention relates to a photosensitive composition and its application.

Conventionally, a method is known in which a conductive layer or a resin insulating layer is formed on a substrate by photocuring using a photosensitive composition containing a photopolymerizable compound and a photopolymerization initiator (see Patent Documents 1 to 6). ). For example, Patent Document 1 discloses that a wiring pattern is formed on a substrate by a photolithography method including a film-like body forming step, an exposure step, a developing step, and a firing step. In this method, first, in a step of forming a film-like body, a photosensitive composition is applied to a substrate by a printing method or the like and dried to form the film-like body. Then, in the exposure step, the formed film-shaped body is covered with a photomask having a predetermined opening pattern, and then the film-shaped body is exposed through the photomask. Thereby, the exposed part of a film-shaped body is light-hardened. Then, in the developing step, the unexposed portion shielded by the photomask is etched with an alkaline etchant and removed. Then, in the calcination step, the film-like body that becomes a desired development pattern is calcined. According to the method, a high-definition patterned conductive layer can be formed compared to various previous printing methods.
[Prior Art Literature]
[Patent Literature]

[Patent Document 1] Japanese Patent No. 4437603
[Patent Document 2] Japanese Patent No. 4095163
[Patent Document 3] Japanese Patent Application Publication No. 2003-183401
[Patent Document 4] Japanese Patent Application Publication No. 2015-110745
[Patent Document 5] Japanese Patent Application Publication No. 2015-184631
[Patent Document 6] Japanese Patent No. 5933402

However, in recent years, the miniaturization or high performance of various electronic devices has been rapidly developed, and further miniaturization or high density of electronic components mounted in electronic devices is required. Along with this, when manufacturing electronic parts, it is required to reduce the resistance of the conductive layer and reduce the thickness (narrowing) of the conductive layer. For example, it is required to form a conductive layer including a thin line-shaped wiring (hereinafter, sometimes referred to as a “fine line”) having a line width of 30 μm or less.

However, according to a study by the present inventors, it is difficult to form a thin solid line stably by using a conventional photosensitive composition as described in the aforementioned patent document. For example, the unexposed portion may not be completely removed in the developing step, so that adjacent wirings are connected to each other and short-circuit failure occurs. In addition, if the time of the development step is set to be long in order to suppress the occurrence of such a short-circuit failure, the exposed portion may become thinner, and peeling or disconnection may occur in the development pattern.

It is considered that one cause of the problem is a short development margin. Here, the "developing margin" means that in the developing step, from the point (breakpoint (BP)) of the unexposed portion is completely removed to the occurrence of defects such as peeling or disconnection in the exposed portion constituting the developing pattern. The length of time. That is, if the development margin is not sufficiently ensured, the unexposed portion is thinned or disappeared immediately after the unexposed portion is removed. Therefore, especially in the case of forming a thin solid line, it is difficult to discern the timing of ending the development step. Therefore, in terms of step management, there is a need for a technology that can ensure a long development margin (for example, 10 seconds or more) and form a thin solid line with good reproducibility.

The present invention has been made in view of the above-mentioned aspects, and an object thereof is to provide a photosensitive composition that has a long development margin and can form a thin solid line stably. Another related object is to provide a composite including a conductive film including a dried body of the photosensitive composition. Another related object is to provide an electronic component including a conductive layer including a fired body of the photosensitive composition, and a method for manufacturing the electronic component.

According to the present invention, there is provided a photosensitive composition for producing a conductive layer including a wiring having a line width of 30 μm or less. The photosensitive composition includes a conductive powder, a photopolymerizable compound, and a photopolymerization initiator. The photopolymerization initiator includes at least the following two components: (1) 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide; (2) α-amino alkyl phenones When the entire photopolymerization initiator is set to 100% by mass, the (1) 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide accounts for 50% by mass or more.

The photosensitive composition contains, as a photopolymerization initiator, at least the two components (1) and (2). Thereby, the development margin time can be ensured for a long time in the development step, and the fine line formability of the exposed portion can be improved. As a result, even a thin solid line with a line width of 30 μm or less can be formed with good reproducibility. In addition, it is possible to suppress the occurrence of defects such as short circuit failure, peeling, and disconnection, thereby improving the yield.

In a preferred aspect disclosed herein, the (1) 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide and the (2) α-aminoacetophenone The mass ratio of the class is 50:50 to 90:10. Thereby, the formation of fine lines can be improved better, and the effect of the technology disclosed herein can be exerted at a higher level. For example, the conductive layer can be formed with high accuracy even if the conductive layer is further thinned.

In a preferred aspect disclosed herein, the (1) 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide and the (2) α-aminoacetophenone The mass ratio of the class is 50:50 to 85:15. Thereby, it is possible to better improve the etching resistance of the exposed portion, and to suppress the peeling of the conductive layer at a higher level.

In a preferred aspect disclosed herein, when the entire photosensitive composition is 100% by mass, the proportion of the photopolymerization initiator is 2% by mass or less. Thereby, at least one of the effect of securing the development time for a longer period of time and the effect of improving the fine line formability is exhibited.

In a preferred aspect disclosed herein, the photopolymerizable compound includes a photopolymerizable compound having a urethane bond. Thereby, the conductive film containing the dried body of the photosensitive composition can be made excellent in flexibility or stretchability. In addition, it is possible to further improve the etching resistance of the exposed portion. As a result, it is possible to improve the adhesion between the substrate and the conductive layer, and to suppress the occurrence of defects such as peeling at a higher level.

In a preferred aspect disclosed herein, the conductive powder includes silver-based particles. Thereby, a conductive layer excellent in balance between cost and low resistance can be realized.

In a preferred aspect disclosed herein, the conductive powder includes core-shell particles, and the core-shell particles include a core portion including a metallic material, and at least a portion of a surface of the core portion is covered and includes Covered part of ceramic material. Thereby, the etching resistance of an exposed part can be improved more, and the fine-line formation property can be improved more. In addition, in the application for manufacturing a ceramic electronic component having a conductive layer on a ceramic substrate (ceramic substrate), the integration of the ceramic substrate and the conductive layer can be improved, and the durability of the ceramic electronic component can be improved.

In a preferred aspect disclosed herein, in the L * a * b * color system based on Japanese Industrial Standards (JIS) JIS Z 8781: 2013, the brightness L of the conductive powder is * It is 50 or more. Thereby, in the exposure step, light reaches the deep part of the exposed part stably, and a thick film-like conductive layer can also be stably realized.

In a preferable aspect disclosed herein, the photosensitive composition further contains an organic solvent having a boiling point of 150 ° C or higher and 250 ° C or lower. Thereby, the storage stability of the photosensitive composition and the operability at the time of formation of a conductive film can be improved, and the drying temperature after printing can be suppressed low.

In addition, according to the present invention, there is provided a composite including: a green sheet; and a conductive film, the conductive film being disposed on the green sheet and including a dried body of the photosensitive composition.

In addition, according to the present invention, there is provided an electronic component including a conductive layer including a fired body of the photosensitive composition. According to the photosensitive composition, a fine solid line can be stably realized. Therefore, an electronic component having a small and / or high-density conductive layer can be preferably realized.

In addition, according to the present invention, there is provided a method for manufacturing an electronic component, which includes the steps of: applying the photosensitive composition to a substrate, and calcining after exposure and development to form a calcination including the photosensitive composition. Body's conductive layer. The development margin of the photosensitive composition is ensured for a long time. Therefore, according to this manufacturing method, an electronic component having a small and / or high-density conductive layer can be stably manufactured, and the yield can be improved.

Hereinafter, preferred embodiments of the present invention will be described. Furthermore, matters other than those specifically mentioned in this specification (for example, a photopolymerization initiator contained in a photosensitive composition) are matters required for the implementation of the present invention (for example, a photosensitive composition (Manufacturing method, forming method of conductive film or conductive layer, manufacturing method of electronic parts, etc.) can be understood based on the technical content pointed out in this specification and the general technical knowledge of practitioners in the field. The present invention can be implemented based on the contents disclosed in this specification and technical common sense in the field.

In addition, in the following description, a film-like body obtained by drying the photosensitive composition at a temperature below the boiling point of the photopolymerizable compound and the photopolymerization initiator, specifically about 200 ° C or lower, for example, 100 ° C or lower (Dry matter) is called "conductive film". The conductive film includes all the film-like bodies that have not been calcined (before calcination). The conductive film may be an uncured material before light curing or a cured material after light curing. In the following description, a sintered body (fired product) obtained by firing a photosensitive composition at a temperature higher than the sintering temperature of the conductive powder is referred to as a "conductive layer". The conductive layer includes a wiring (linear body) and a wiring pattern.
In addition, the expression "A to B" which shows a range in this specification means A or more and B or less.

`` Photosensitive composition ''
The photosensitive composition disclosed here is a conductive layer for producing a wiring including a thin solid line having a line width (line width) of 30 μm or less after firing. For example, it is preferably used to form a conductive film including a portion having a line width (line width) of 30 μm or less. The photosensitive composition disclosed here contains a conductive powder, a photopolymerizable compound, and a photopolymerization initiator as essential components. Hereinafter, each component will be described in order.

＜ Conductive powder ＞
The conductive powder is a component that imparts electrical conductivity to a conductive layer obtained by firing a photosensitive composition. There are no particular limitations on the conductive powder, and one or two or more of them can be appropriately selected from known ones, for example, depending on the application and the like. Preferred examples of the conductive powder include gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd), aluminum (Al), nickel (Ni), and ruthenium ( Ru), rhodium (Rh), tungsten (W), iridium (Ir), osmium (Os) and other metal monomers, and mixtures or alloys of these metal monomers. Examples of the alloy include silver alloys such as silver-palladium (Ag-Pd), silver-platinum (Ag-Pt), and silver-copper (Ag-Cu).

In a preferred aspect, the conductive powder includes silver-based particles. Silver is relatively inexpensive and highly conductive. Therefore, when the conductive powder contains silver-based particles, a conductive layer excellent in balance between cost and low resistance can be realized. It should be noted that the term "silver-based particles" as used in this specification includes those that all contain a silver component. Examples of the silver-based particles include core-shell particles using a monomer of silver, the silver alloy, and silver-based particles as a core.

In another preferred aspect, the conductive powder includes metal-ceramic core-shell particles. The metal-ceramic core-shell particle includes a core portion including a metal material, and a coating portion that covers at least a part of a surface of the core portion and includes a ceramic material. Ceramic materials are excellent in chemical stability, heat resistance, and durability. Therefore, by adopting the form of the core-shell particles of the metal-ceramic, the stability of the conductive powder in the photosensitive composition can be further improved, and the fine-line forming property can be further improved. In addition, in applications for manufacturing ceramic electronic parts, the integrity of the ceramic substrate and the conductive layer can be improved, and the durability of the ceramic electronic parts can be improved.

Among the metal-ceramic core-shell particles, examples of the metal material constituting the core portion include a monomer of the metal and a mixture or alloy of the metal monomers. Among these, silver-based particles are preferred. In other words, the conductive powder preferably contains silver-ceramic core-shell particles.

The ceramic material constituting the coating portion is not particularly limited, and examples thereof include zirconia, magnesia, alumina, silica, titanium oxide, and cerium oxide ( ceria), yttria, barium titanate and other oxide-based materials; cordierite, mullite, forsterite, steasite, silico-aluminum oxynitride (Sialon), zircon (zircon), ferrite, and other composite oxide-based materials; silicon nitride (silicon nitride), aluminum nitride (aluminum nitride) and other nitride-based materials; silicon carbide (silicon carbide) And other carbide-based materials; hydroxyapatite (hydroxyapatite) and other hydroxide-based materials; etc. For example, in the application in which a conductive layer is formed on a ceramic substrate to produce a ceramic electronic component, a ceramic material of the same type or an excellent affinity as the ceramic substrate is preferred.

Although not particularly limited, the content ratio of the ceramic material in the metal-ceramic core-shell particles may be, for example, 0.01 to 5.0 parts by mass relative to 100 parts by mass of the metal material in 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 was the applicant's earlier application, the metallic material and the organic metal compound (for example, a metal alkoxide) having a target metal element can be used Or chelating compounds) or oxide sol.

Although not particularly limited, the D ₅₀ particle diameter of the conductive powder may be about 1.0 μm to 5.0 μm in terms of balance with the exposure performance in the exposure step. By setting the D ₅₀ particle diameter to the above range, the exposure performance of the exposed portion can be improved, and a fine solid line can be formed more stably. The “D ₅₀ particle size” in this specification refers to a particle size distribution corresponding to 50% of the cumulative value from the side with a smaller particle size in the particle size distribution based on the volume basis of the laser diffraction and scattering method. .
From the viewpoint of suppressing aggregation in the photosensitive composition and improving stability, the D ₅₀ particle diameter of the conductive powder may be, for example, 1.5 μm or more, 2.0 μm or more, and 2.5 μm 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 improving the formation of fine wires or promoting the densification or reduction of the electrical resistance of the conductive layer.

Although not particularly limited, the particle size distribution of the entire conductive powder may have multimodality. In other words, the first conductive powder and the second conductive powder having different D ₅₀ particle diameters may be included. Whereby, as compared with the difference between the diameter ₅₀ of the first conductive powder and the second conductive powder D is small, can improve compactness or filling conductive layer, and suitably reduce the resistance. The D ₅₀ particle size of the first conductive powder and the second conductive powder may differ by at least 0.5 μm, typically 0.5 μm to 3.0 μm, for example, about 1.0 μm to 2.0 μm. In a specific example, the D ₅₀ particle size of the first conductive powder may be in a range of approximately 3 μm to 5 μm, for example, 3.5 μm to 4.5 μm, and the D ₅₀ particle size of the second conductive powder may be in a range of approximately 1 μm to 3.5 μm, for example, in a range of 1.5 μm to 3 μm.

Although not particularly limited, the shape of the conductive particles constituting the conductive powder is typically a substantially spherical shape having an average aspect ratio (longer diameter / shorter diameter ratio) of about 1 to 2, preferably 1 to 1.5, for example 1 Spherical to ~ 1.2. This makes it possible to achieve more stable exposure performance. The average aspect ratio of the conductive powder may be in the range. In addition, the "average aspect ratio" as used in this specification means the calculated average value of the aspect ratio calculated from the observation image obtained by observing a several electroconductive particle with an electron microscope. The term "spherical shape" as used in this specification refers to a form that can be roughly regarded as a sphere (ball) as a whole, and is a term that can include ellipses, polyhedrons, disks, and the like.

Although not particularly limited, the entire conductive powder is in the L * a * b * color system based on Japanese Industrial Standard JIS Z 8781: 2013, and the lightness L * may be 50 or more. Thereby, in the exposure step, the irradiation light stably reaches the deep part of the exposed portion, and for example, a thick conductive layer having a film thickness of 5 μm or more and further 10 μm or more can be stably realized. From this viewpoint, the lightness L * of the conductive powder may be about 55 or more, for example, 60 or more. The lightness L * can be adjusted by, for example, the type of the conductive powder or the D ₅₀ particle size. The measurement of the lightness L * can be performed using, for example, a spectrophotometer based on Japanese Industrial Standard JIS Z 8722: 2009.

Furthermore, an organic surface treatment agent may be adhered to the surface of the conductive powder. The organic surface treatment agent can be used, for example, for at least one of the purpose of improving the dispersibility of the conductive powder in the photosensitive composition, improving the affinity with other contained components, preventing the surface oxidation of the metal constituting the conductive powder, and the like. Examples of the organic surface treatment agent include fatty acids such as carboxylic acids, and benzotriazole-based compounds.

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, it is possible to form a conductive layer excellent in denseness or electrical conductivity. In addition, it is possible to improve the operability of the photosensitive composition or the workability when the conductive film is molded.

<Photopolymerizable compound>
A photopolymerizable compound is a component which polymerizes and hardens by the active species which generate | occur | produce the decomposition | disassembly of the photopolymerization initiator mentioned later. The polymerization reaction may be addition polymerization or ring-opening polymerization. Typically, a photopolymerizable compound has one or more unsaturated bonds and / or a cyclic structure. The photopolymerizable compound includes a monomer, a polymer, and an oligomer. Among these, a monomer is preferable. The photopolymerizable compound is not particularly limited, and one or two or more kinds can be appropriately selected and used from conventionally known ones, for example, depending on the application, the type of the substrate, and the like. As a preferable example of the photopolymerizable compound, a radically polymerizable monomer having one or more unsaturated bonds such as a (meth) acrylfluorenyl group or a vinyl group, or an epoxy group or the like Cationic polymerizable monomer having a cyclic structure.

In a preferred aspect, the photopolymerizable compound includes a (meth) acrylic acid ester monomer having a (meth) acrylfluorenyl group. By including a (meth) acrylic acid ester monomer, the flexibility of a conductive layer or the followability to a base material can be improved. As a result, it is possible to suppress the occurrence of defects such as peeling or disconnection at a higher level. In addition, in the present specification, the term "(meth) acrylfluorenyl" includes terms such as "methacrylfluorenyl" and "acrylfluorenyl", and the term "(meth) acrylic acid ester" includes "formyl "Acrylate" and "acrylate". In addition, the (meth) acrylate monomer includes: a monofunctional (meth) acrylate having one functional group per molecule; a polyfunctional (meth) acrylate having two or more functional groups per molecule; and Such modifications.

As a preferable example of the (meth) acrylate monomer, triethylene glycol monoacrylate, triethylene glycol monomethacrylate, tetraethylene glycol monoacrylate, and tetraethylene glycol monomethyl Acrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tripentaerythritol heptaacrylate, tripentaerythritol octaacrylate, tetrapentaerythritol nine acrylate, tetrapentaerythritol ten acrylic Polyfunctional (meth) acrylates such as esters. Among these, a monomer having five or more (meth) acrylfluorenyl groups per molecule is preferred from the viewpoint of improving photocurability.

In another preferable aspect, the photopolymerizable compound includes a photopolymerizable compound (a urethane bond-containing compound) having a urethane bond (-NH-C (= O) -O-). ). Thereby, it is possible to better improve the etching resistance of the exposed portion, and to realize a conductive layer excellent in flexibility or stretchability. Therefore, it is possible to improve the adhesion between the substrate and the conductive layer, and to suppress the occurrence of defects such as peeling or disconnection at a higher level. As a preferable example of a urethane bond containing compound, a urethane modified (meth) acrylate, a urethane modified epoxy, etc. are mentioned. The proportion of the urethane bond-containing compound in the entire photopolymerizable compound is more preferably about 30% by mass or more, typically 50% by mass or more, and for example, 95% by mass or more It is substantially 100% by mass.

Although not particularly limited, the weight-average molecular weight of the photopolymerizable compound may be approximately 100 to 10,000, typically 200 to 5,000, and for example 300 to 2,000. The "weight-average molecular weight" as used in this specification refers to a measurement by gel chromatography (Gel Permeation Chromatography (GPC)) and conversion using a standard polystyrene calibration curve Weight average molecular weight. When a photopolymerizable compound is a monomer, it has the same meaning as molecular weight.

Although not particularly limited, the proportion of the photopolymerizable compound in the entire photosensitive composition may be approximately 0.1% to 20% by mass, typically 0.5% to 10% by mass, for example, 2% to 8% by mass The mass% is further 3 mass% to 6 mass%. By satisfying the above range, the photocurability of the photosensitive composition can be fully exhibited, and the conductive layer can be stably formed at a higher level.

<Photopolymerization initiator>
A photopolymerization initiator is a component which decomposes by irradiation of light energy, such as an ultraviolet-ray, and generates active species, such as a radical and a cation, and starts a polymerization reaction of a photopolymerizable compound. In the photosensitive composition disclosed herein, the photopolymerization initiator must contain at least the following two components: (1) 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide; (2) ) Α-Aminoalkylphenones.

Typically, the absorption wavelengths of the photopolymerization initiators (1) and (2) are different from each other. Therefore, by using these photopolymerization initiators in combination, the absorption wavelength region is expanded compared to the case where a single photopolymerization initiator is used alone, and active species can be generated with high efficiency. In addition, due to the combined effect of the photopolymerization initiators of (1) and (2), in the development step, for example, the time to the break point (BP) is as before, and the development margin can be ensured for a long time. time. The above effects are combined with each other. In the technology disclosed herein, the formation of fine lines can be improved, and even a thin solid line with a line width of 30 μm or less can be formed with good reproducibility. Hereinafter, the photopolymerization initiators (1) and (2) will be described.

(1) 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide is monoacylphosphine oxide (MAPO). Examples of commercially available products include DAROCUR (trademark) TPO, IRGACURE (trademark) TPO (all manufactured by BASF Japan). The fluorenyl phosphine oxide-based photopolymerization initiator is excellent in compatibility with a photopolymerizable compound or an organic dispersion medium. Therefore, it is effective for improving the storage stability of a photosensitive composition.

Furthermore, as the photopolymerization initiator classified into the same fluorenylphosphine oxide based on (1), bisacylphosphine oxide (BAPO), for example, bis (2,4,6) -Trimethylbenzyl) -phenylphosphine oxide. However, as shown in a test example described later, when the bisfluorenylphosphine oxide is used instead of the above-mentioned (1), the effects of the technique disclosed herein as described above are not exerted. That is, it can be said that there is specificity when the photopolymerization initiators (1) and (2) are used in combination.

In the technology disclosed herein, (1) becomes the main body of the photopolymerization initiator. In other words, when the entire photopolymerization initiator is set to 100% by mass, the proportion of (1) described above accounts for 50% by mass or more. Thereby, the fine line forming property can be improved, and a fine solid line can be formed better. From the viewpoint, the ratio (1) may be, for example, 75% by mass or more, preferably 80% by mass or more, and more preferably 85% by mass or more. In addition, from the viewpoint of better exhibiting the combined effect with the above (2), or the viewpoint of improving the adhesion between the substrate and the conductive layer, the ratio of the (1) may be about 90% by mass or less, It is preferably 85% by mass or less.

(2) The α-aminoalkyl phenones may be compounds having an α-amino alkyl phenone skeleton, and one or two or more of them may be appropriately selected from conventionally known ones and used. The α-aminoalkylbenzophenone skeleton can be grasped as a functional group having an intramolecular cleavage-type photopolymerization initiation ability, for example. The alkyl moiety may be linear or branched. The alkyl moiety may have a substituent. A preferable example of the α-aminoalkyl phenones includes compounds having a molecular weight of about 1,000 or less, typically 200 to 500, for example, 250 to 400. As another preferred example, a compound having an α-aminoacetophenone skeleton may be mentioned. As a preferable example of the compound which has an α-aminoacetophenone skeleton, the compound which has a structural part of the following (A) is mentioned.

[Chemical 1]

In the (A), R ¹ and R ² are each independently selected from a hydrocarbon group having 1 to 18 carbon atoms. R ¹ and R ² may be the same or different. R ^{1 is,} for example, an alkyl group having 1 to 18 carbon atoms. The number of carbon atoms of R ¹ is preferably 1 to 8, typically 1 to 4, such as 1, 2 or 3. R ^{2 is,} for example, an alkyl group, an aryl group, or an arylalkyl group having 1 to 18 carbon atoms. The number of carbon atoms in R ² is preferably 1 to 8. R ³ and R ⁴ are each independently selected from a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. R ³ and R ⁴ may be the same or different. R ³ and R ⁴ are each independently an alkyl group having 1 to 18 carbon atoms, an aryl group, an arylalkyl group, or a cyclic alkyl ether group in which R ³ and R ^{4 are} bonded. The total number of carbon atoms of R ³ and R ⁴ is preferably 1 to 8, typically 1 to 6, such as 2 to 4.

Specific examples of the above (2) include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2- (dimethylamino) ) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2-methyl-1- [4- (methyl Thio) phenyl] -2-morpholinopropane-1-one, N, N-dimethylaminoacetophenone, and the like. Examples of commercially available products include: IRGACURE (trademark) 369, IRGACURE (trademark) 379, IRGACURE (trademark) 907 (all BASF JAPAN shares) Co., Ltd.) and so on.

Although not particularly limited, from the viewpoint of exerting the effects of the technology disclosed herein at a high level, when the entire photopolymerization initiator is set to 100% by mass, the ratio of (2) may be approximately 10% by mass or more. In addition, from the viewpoint of improving the adhesion between the substrate and the conductive layer, the ratio (2) may be 15% by mass or more. In addition, from the viewpoint of further improving the fine line formability, the ratio (2) may be, for example, 25% by mass or less, preferably 20% by mass or less, and more preferably 15% by mass or less.

Although not particularly limited, from the viewpoint of exerting the effects of the technology disclosed herein at a high level, when the entire photopolymerization initiator is set to 100% by mass, the total of (1) and (2) described above The ratio may also be approximately 80% by mass or more, preferably 90% by mass or more, and more preferably 95% by mass or more, such as 100% by mass.

Although not particularly limited, the mass ratios of (1) and (2) may be approximately 50:50 to 95: 5. Thereby, the formation of fine lines can be improved, and the effects of the technology disclosed herein can be exerted at a higher level. For example, the conductive layer can be formed with high accuracy even if the conductive layer is further thinned. In addition, from the viewpoint of better improving the etching resistance of the exposed portion and suppressing the peeling of the conductive layer, the mass ratio of (1) and (2) may be preferably 50:50 to 90:10, more preferably It is 50:50 to 85:15.

Although not particularly limited, the proportion of the photopolymerization initiator in the entire photosensitive composition may be approximately 0.01% by mass or more, typically 0.04% by mass or more, for example, 0.05% by mass or more. Thereby, the photocurability of the photosensitive composition can be fully utilized, and the conductive layer can be formed stably. The proportion of the photopolymerization initiator in the entire photosensitive composition may be about 0.5% by mass or less, typically 0.3% by mass or less, preferably 0.2% by mass or less, for example, 0.1% by mass or less. Thereby, in the developing step, the opposite etching resistance and peelability can be balanced at a higher level. Therefore, it is possible to secure the development margin for a longer period of time, and to improve the fine line formability better.

Although not particularly limited, the content ratio of the photopolymerization initiator relative to 100 parts by mass of the conductive powder may be about 0.01 to 1 part by mass, typically 0.02 to 0.2 part by mass, for example, 0.05 part by mass Parts to 0.1 parts by mass. The content ratio of the photopolymerization initiator may be about 0.1 to 25 parts by mass, typically 0.2 to 5 parts by mass, for example, 0.5 to 3 parts by mass, based on 100 parts by mass of the photopolymerizable compound. 1 part by mass to 2 parts by mass.

＜ Organic Adhesives ＞
The photosensitive composition may contain an organic binder in addition to the essential components. An organic binder is a component which improves the adhesiveness of a base material and an unhardened conductive film. As the organic binder, one or two or more kinds can be appropriately selected and used from conventionally known ones according to, for example, the type of the substrate, the type of the photopolymerizable compound, the type of the photopolymerization initiator, and the like. The organic binder is preferably one that can be easily removed with an etchant in the developing step. For example, when an alkaline etching solution is used in the developing step, it is preferable to have a hydroxyl group (-OH), a carboxyl group (-C (= O) OH), an ester bond (-C (= O) O-), A compound having an acidic structural moiety such as sulfo (-SO ₃ H). Thereby, residues are not easily left in the unexposed portion, and for example, the space between the thin solid lines can be stably secured.

A preferable example of the organic binder includes cellulose-based polymers such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, and hydroxymethyl cellulose, acrylic resins, phenol resins, and alkyd resins. , Polyvinyl alcohol, polyvinyl butyral, etc. Among these, from the viewpoint of easy removal in the developing step, a hydrophilic organic binder such as a cellulose polymer or an acrylic resin is preferred.

When an organic binder is contained in the photosensitive composition, it is not particularly limited, and the proportion of the organic binder in the entire photosensitive composition may also be about 0.1% to 20% by mass, typically 0.5. Mass% to 10% by mass, for example, 1% to 5% by mass. In addition, although not particularly limited, the content ratio of the photopolymerizable compound and the organic binder may be approximately equal (the difference between the content ratios of the two is approximately 1% by mass or less, for example, 0.5% by mass or less). Accordingly, in the developing step, the opposite etching resistance (adhesiveness) and peelability can be balanced at a higher level.

＜ Organic Dispersion Medium ＞
The photosensitive composition may contain, in addition to the above-mentioned essential components, an organic dispersion medium for dispersing these. An organic dispersion medium is a component which imparts moderate viscosity or fluidity to a photosensitive composition, improves the handleability of a photosensitive composition, or improves the workability at the time of shaping a conductive film. As the organic dispersion medium, one or two or more kinds can be appropriately selected and used from conventionally known ones, for example, depending on the type of the photopolymerizable compound or the photopolymerization initiator.

A preferred example of the organic dispersion medium includes terpineol, dihydroterpineol (menthanol), texanol, and 3-methyl-3-methoxy. Alcohol solvents such as butanol and benzyl alcohol; glycol solvents such as ethylene glycol, propylene glycol, and diethylene glycol; dipropylene glycol methyl ether, methyl cellosolve (ethylene glycol monomethyl ether), and cellosolve (B Ether solvents such as glycol monoethyl ether), butylcarbitol (diethylene glycol monobutyl ether); diethylene glycol monobutyl ether acetate, dipropylene glycol methyl ether acetate, butyl ethylene glycol (Butyl glycol acetate), butyldiglycol acetate, butyl cellosolve acetate, butylcarbitol acetate (diethylene glycol monobutyl ether acetate), acetic acid Esters such as isobornyl esters; hydrocarbon solvents such as toluene, xylene, naphtha, petroleum hydrocarbons; mineral spirit; and other organic solvents.

Among them, an organic solvent having a boiling point of 150 ° C. or higher, and further an organic solvent of 170 ° C. or higher is preferred from the viewpoint of improving the storage stability of the photosensitive composition or the operability during formation of the conductive film. In addition, as another preferable example, an organic solvent having a boiling point of 250 ° C. or lower, and an organic solvent having a boiling point of 220 ° C. or lower are preferred from the viewpoint of suppressing the drying temperature after printing the conductive film to a low level. This can improve productivity and reduce production costs.

In addition, for example, in the application for forming a ceramic electronic component by forming a conductive layer on a ceramic substrate, an organic solvent having low permeability to a ceramic green sheet is preferred. Examples of the organic solvent having low permeability to the ceramic green sheet include an organic solvent having a three-dimensional bulk structure such as a cyclohexyl group or a third butyl group, or an organic solvent having a relatively large molecular weight. Furthermore, for example, it is also preferable that the organic solvent having low permeability to the ceramic green sheet as described above and the component (for example, a photopolymerizable substance and / or photopolymerization) contained in the photosensitive composition can be better dissolved. The organic solvent of the initiator) is mixed in an arbitrary ratio and used as an organic dispersion medium.

Examples of commercially available organic solvents having such properties (boiling point and permeability to ceramic green sheets) include Dowanol DPM (trademark) (boiling point: 190 ° C, Dow Chemical Co., Ltd. ( (Manufactured by Dow Chemical Company), Dowanol DPMA (trademark) (boiling point: 209 ° C, manufactured by Dow Chemical Company), menthol (boiling point: 207 ° C), menthol P (boiling point: 216 ° C), Isopar H (boiling point: 176 ° C, manufactured by Kanto Fuel Co., Ltd.), SW-1800 (boiling point: 198 ° C, manufactured by Maruzan Petroleum Co., Ltd.), etc.

When an organic dispersion medium is contained in the photosensitive composition, it is not particularly limited, but the proportion of the organic dispersion medium in the entire photosensitive composition may also be approximately 1% to 50% by mass. It is 3 to 30% by mass, for example, 5 to 20% by mass.

＜ Other ingredients ＞
As long as the photosensitive composition does not significantly impair the effect of the technology disclosed herein, it may contain various additional components in addition to the components described above, as necessary. As the additive component, one kind or two or more kinds can be appropriately selected from conventionally known ones and used. Examples of the additive component include inorganic fillers, photosensitizers, polymerization inhibitors, radical scavengers, antioxidants, ultraviolet absorbers, plasticizers, surfactants, leveling agents, thickeners, Dispersant, defoamer, anti-gelling agent, stabilizer, preservative, pigment, etc. Although not particularly limited, the proportion of the additive component in the entire photosensitive composition may be about 5 mass% or less, for example, 3 mass% or less.

As described above, the photosensitive composition disclosed herein contains both the components (1) and (2) as a photopolymerization initiator. When the entire photopolymerization initiator is 100% by mass, the ratio of (1) is 50% by mass or more. Thereby, the etching resistance (adhesion) and the peelability can be balanced at a higher level in the developing step. That is, it is possible to improve the etching resistance of the exposed portion and to secure a long development time. As a result, the exposed portion can be appropriately left on the substrate after the development step, and occurrence of defects such as peeling or disconnection can be suppressed. In addition, the peelability of the conductive film can be improved, the unexposed portions can be appropriately removed, and the exposed portions can be prevented from becoming too thick. In other words, the fine line formability of the exposed portion can be improved. As a result, it is possible to stably secure a space between adjacent wirings, and it is possible to suppress occurrence of short-circuit failure. In addition, according to the technology disclosed here, these effects are combined with each other, and even a thin solid line with a line width of 30 μm or less can be formed with good reproducibility. In addition, yield can be improved.

＜ Application of photosensitive composition ＞
According to the photosensitive composition disclosed herein, it is possible to stably form a fine solid line with a finer line width than 30 μm at a high resolution. In addition, peeling or disconnection of the conductive layer can be reduced, and occurrence of short-circuit failure can be suppressed. Therefore, the photosensitive composition disclosed herein can be preferably used, for example, to form conductive layers in various electronic components such as inductance components, capacitor components, and multilayer circuit boards.

The electronic parts can be electronic parts of various mounting forms such as a surface mounting type or a through hole mounting type. The electronic component may be a laminated type, or may be a winding type, or may be a thin film type. Typical examples of inductive components include high-frequency filters, common mode filters, inductors (coils) for high-frequency circuits, inductors (coils) for general circuits, high-frequency filters, and Choking coil, transformer, etc.

In addition, the photosensitive composition in which the conductive powder contains metal-ceramic core-shell particles can be preferably used for forming a conductive layer of a ceramic electronic component. In addition, in this specification, a "ceramic electronic component" includes all the electronic components which have an amorphous ceramic substrate (glass ceramic substrate) or a crystalline (that is, non-glass) ceramic substrate. Typical examples include high-frequency filters with ceramic substrates, ceramic inductors (coils), ceramic capacitors, low-temperature calcined laminated ceramic substrates (Low Temperature Co-fired Ceramics Substrate: LTCC) Substrate)), high-temperature calcined laminated ceramic substrate (High Temperature Co-fired Ceramics Substrate: HTCC substrate), etc.

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

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

The main body portion 10 has a structure in which a ceramic layer (dielectric layer) 12 and an internal electrode layer 14 are integrated. The ceramic layer 12 is made of a ceramic material as described above, for example, as a coating part that can constitute a conductive powder. In the vertical direction Y, an internal electrode layer 14 is disposed between the ceramic layers 12. The internal electrode layer 14 is formed using the 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 a via 16 provided in the ceramic layer 12. Thereby, the internal electrode layer 14 is formed into a three-dimensional spiral shape (spiral shape). Both ends of the internal electrode layer 14 are connected to the external electrode 20, respectively.

Such a multilayer chip inductor 1 can be manufactured in the following procedure, for example.
That is, first, a paste including a ceramic material as a raw material, a binder resin, and an organic solvent is prepared and supplied to a carrier sheet to form a ceramic green sheet. Next, after rolling the ceramic green sheet, the ceramic green sheet is cut into a desired size to obtain a plurality of green sheets for forming a ceramic layer. Then, a via hole is appropriately formed at a predetermined position of the plurality of green sheets for forming ceramic layers using a punch or the like.

Next, a conductive film having a predetermined coil pattern is formed at a predetermined position on a plurality of green sheets for forming a ceramic layer using the photosensitive composition. As an example, a non-calcined conductive film can be formed by a manufacturing method including the following steps: (Step S1: Step of forming a film-like body) A photosensitive composition is applied to a green sheet for forming a ceramic layer, and is dried. This step is a step of forming a conductive film including a dried body of the photosensitive composition; (Step S2: exposure step) covering the conductive film with a photomask having a predetermined opening pattern, and exposing through the photomask to partially make the conductive film. Photo-hardening step; (Step S3: developing step) a step of etching the photo-cured conductive film and removing unexposed portions.

When a conductive film is formed using the photosensitive composition, a conventionally known method can be appropriately used. For example, in (step S1), application of a photosensitive composition can be performed using various printing methods, such as screen printing, or a bar coater. The photosensitive composition can be dried at a temperature below the boiling point of the photopolymerizable compound and the photopolymerization initiator, typically at 50 ° C to 100 ° C. In (Step S2), an exposure machine that emits light in a wavelength range of 10 nm to 500 nm, such as a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like, can be used for the exposure. In (step S3), during etching, an alkaline etchant is typically used. For example, an aqueous solution containing sodium hydroxide, sodium carbonate, or the like can be used. The concentration of the alkaline aqueous solution can be adjusted, for example, from 0.01% by mass to 0.5% by mass.

Next, (step S4: firing step) a plurality of green sheets for forming a ceramic layer on which a conductive film in an unfired state is formed are laminated and pressure-bonded. Thereby, a laminated body of a ceramic green sheet which is not calcined is produced. Then, the laminated body of a ceramic green sheet is fired at 600 to 1000 ° C, for example. Thereby, the ceramic green sheet is integrally sintered to form a main body portion 10 including a ceramic layer 12 and an internal electrode layer 14 containing a fired body of a photosensitive composition. Then, an appropriate external electrode forming paste is applied to both end portions of the main body portion 10 and then fired to form the external electrode 20.
In this way, a multilayer chip inductor 1 can be manufactured.

Hereinafter, several embodiments related to the present invention will be described, but it is not intended to limit the present invention to those shown in the embodiments.

(Preparation of silver powder)
First, two commercially available silver powders (silver powder a, silver powder b) having different D ₅₀ particle sizes were prepared. The D ₅₀ particle diameter of the silver powder a was 3.9 μm, and the D ₅₀ particle diameter of the silver powder b was 2.8 μm. In addition, both the silver powder a and the silver powder b are in the L * a * b * color system based on Japanese Industrial Standard JIS Z 8781: 2013, and the lightness L * is 50 to 80.

The silver powder a is used to prepare the silver powder c. Specifically, zirconyl butoxyl was first added to methanol to prepare a coating liquid. Then, silver powder a was added to this coating liquid, and it stirred for 1 hour. Then, the solid content was recovered from the coating liquid and dried at 100 ° C. Thereby, a silver powder (silver-zirconia core-shell particles) was obtained by surface coating with zirconium oxide (ZrO ₂ ) conversion in an amount of 0.5 parts by mass based on 100 parts by mass of silver powder. ). In this way, silver powder c was prepared.

(Preparation of photopolymerization initiator)
Then, four commercially available photopolymerization initiators (initiator a to initiator d) shown below were prepared. In addition, the initiator a and the initiator b are α-aminoalkyl phenone-based photopolymerization initiators, and the initiator c and the initiator d are fluorenylphosphine oxide-based photopolymerization initiators. .
· Initiator a: 2-benzyl-2-dimethylamino-1- (4-morpholinylphenyl) butanone-1
· Starter b: 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-but Ketone · Initiator c: 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide · Initiator d: bis (2,4,6-trimethylbenzylidene)- Phenylphosphine oxide

(Preparation of photosensitive composition)
First, a urethane acrylate monomer as a photopolymerizable compound, an organic binder, and the photopolymerization initiator are weighed so as to have a content ratio shown in Table 1, and dissolved in an organic system. The dispersion medium is used to prepare a vehicle. Then, the prepared silver powder was mixed with the prepared vehicle at a mass ratio of 77:23 to prepare a photosensitive composition (Examples 1 to 7, and Comparative Examples 1 to 6). In addition, the mass ratio shown in Table 1 is a mass ratio when the entire photosensitive composition is 100% by mass, and when the total mass ratio shown in Table 1 is less than 100% by mass, it includes Trace amounts of other added ingredients (for example, polymerization inhibitors, sensitizers, anti-gelling agents, UV absorbers).

(Production of wiring pattern)
First, using a stainless steel screen, the prepared photosensitive composition was coated on a commercially available ceramic green sheet, respectively. Then, it was made to dry at 60 degreeC for 15 minutes, and the electroconductive film was shape | molded on the green sheet (forming process of a film-like body). Then, a photomask is covered from above the conductive film. At this time, as the mask, a spiral pattern with a line width of 25 μm and a space pattern (space) between adjacent lines of 25 μm (L / S = 25 μm / 25 μm) was used. . In a state covered with the photomask, the exposure part is irradiated with light at an intensity of 2500 mJ / cm ² to harden the exposed portion (exposure step). After the exposure, a 0.1% by mass alkaline Na ₂ CO ₃ aqueous solution was sprayed on the surface of the ceramic green sheet until the break point (BP) was reached (development step). Here, as BP, the time until the unexposed part was developed with 0.1% by mass of an alkaline etching solution until the unexposed part disappeared visually was confirmed. After the unexposed portion is removed in this manner, it is washed with pure water, and dried at room temperature. Then, it was calcined at 700 ° C (calcination step). In this manner, a conductive layer having a wiring pattern in which spiral-shaped wirings are arranged is formed on the ceramic green sheet.

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

Evaluation of peeling:
The wiring pattern was observed with an electron microscope, and peeling was evaluated. Furthermore, the observation image was taken at a magnification of 200 times. Then, the presence or absence of peeling and disconnection was confirmed in the obtained observation image. The results are shown in the "Evaluation of peeling" column in Table 1. The expressions in this column are as follows.
"○": No peeling "△": Partial peeling (no disconnection)
"×": peeling or disconnection

· Evaluation of line width:
The line width of the wiring pattern is measured based on the observation image. In addition, the measurement of the line width is performed for a plurality of fields of view, and the arithmetic mean thereof is set to the line width (μm). The results are shown in the "line width" column of Table 1. The expression in the evaluation column is as follows.
"○": 20 μm to 30 μm (within the range of the target value)
“×”: 30 μm or more In addition, the evaluation results of Comparative Examples 1 to 3 and Examples 1 to 4 in FIG. 2 show the relationship between the content ratio of the initiator c and the line width of the wiring pattern.

Evaluation of development margin:
In the exposure step, an alkaline etchant is sprayed for 10 seconds (BP + 10 seconds) after the break point. Then, the conductive film after the exposure step was observed with an electron microscope in the same manner as described above, and the development margin was evaluated based on the obtained observation image. The results are shown in the "Evaluation of development margin" column in Table 1. The expressions in this column are as follows.
"○": The shape of the conductive film is maintained "×": The shape of the conductive film is not maintained

·Overview:
"○": In each evaluation of the peeling, line width, and development margin, neither △ nor × existed (all ○)
"△": In each evaluation of the peeling, line width, and development margin, △ is one, and the rest are ○
"×": In each evaluation of the peeling, line width, and development margin, there is one or more ×

[Table 1]

Comparative Examples 1 and 2 are test examples using only the initiator a. As shown in Table 1, in Comparative Example 1, the development margin was secured for 10 seconds or more, but the line width in the conductive pattern had a large deviation, and it was confirmed that the line width became thick everywhere. As a result, the line width becomes too large compared with the target value, and it is difficult to form a thin solid line stably. In addition, in Comparative Example 2 in which the content ratio of the initiator a was reduced compared to Comparative Example 1, the development margin was not sufficiently secured. Comparative Example 4 is a test example using only the initiator c. As shown in Table 1, in Comparative Example 4, peeling or disconnection of the conductive pattern was confirmed, and formation of a thin solid line itself was already difficult.

Comparative Examples 3 and 1 to 4 are test examples in which the initiator a and the initiator c are used in combination. As shown in Table 1 and FIG. 2, in Comparative Example 3 in which the content ratio of the initiator c was small, the effect of the addition of the initiator c was not sufficiently exhibited. As in Comparative Example 1, it was difficult to form a thin solid line stably. . On the other hand, in Examples 1 to 4, in which the content ratio of the initiator c was 50% by mass or more of the entire photopolymerization initiator, the development margin was sufficiently ensured, and the fine line width required was stably formed. solid line. In addition, by increasing the content ratio of the initiator c, the fine-line forming property is further improved. In particular, in Examples 1 to 3 in which the mass ratio of the initiator c: the initiator a is 50:50 to 85:15, the etching resistance of the exposed portion is improved, and the peeling of the conductive layer is more effectively suppressed. .

Example 5 is a test example using the same α-aminoalkylbenzophenone-based initiator b instead of the initiator a. As shown in Table 1, in Example 5, as in Examples 1 to 4, the development margin was sufficiently secured, and stable formation of a thin solid line was achieved. In other words, when the initiator b is used instead of the initiator a, the effect of the technique disclosed herein is also exerted.

Comparative Examples 5 and 6 are test examples in which the same fluorenylphosphine oxide-based initiator d was used instead of the initiator c. As shown in Table 1, in Comparative Examples 5 and 6, unlike Examples 1 to 4, the development margin was insufficient, and / or it was difficult to form a thin solid line stably. In other words, when the initiator d is used instead of the initiator c, the effect of the technique disclosed here is not exerted.

Examples 6 and 7 are test examples using silver powder c instead of silver powder a and silver powder b. As shown in Table 1, in Examples 6 and 7, as in Examples 1 to 4, the development margin was sufficiently ensured, and stable formation of a thin solid line was achieved. Furthermore, compared with the case where the silver powder a and the silver powder b are used, the effect of the technique disclosed here is exhibited at a higher level, and the fine line formability is further improved.

As described above, as the photopolymerization initiator, 2,4,6-trimethylbenzyl-diphenyl-phosphine oxide (starter c) and α-aminoalkyl phenones (from The initiator a, the initiator b), and including 2,4,6-trimethylbenzyl-diphenyl-phosphine oxide in a proportion of 50% by mass or more of the entire photopolymerization initiator, In the developing step, it is possible to ensure a long development margin time. In addition, the fine line formability of the exposed portion can be improved. Thereby, even a thin solid line with a line width of 30 μm or less can be formed with good reproducibility. In addition, it can suppress the occurrence of short-circuit failure, peeling, and disconnection, and improve the yield. These results indicate the significance of the techniques disclosed herein.

The present invention has been described in detail above, but these are merely examples, and the present invention can be modified in various ways without departing from the spirit thereof.

1‧‧‧Multilayer Chip Inductor

10‧‧‧Body

12‧‧‧Ceramic layer (dielectric layer)

14‧‧‧Internal electrode layer

16‧‧‧ access

20‧‧‧External electrode

X‧‧‧ Left and right direction

Y‧‧‧ Up and down direction

FIG. 1 is a cross-sectional view schematically showing a structure of a multilayer chip inductor according to an embodiment.

FIG. 2 is a graph showing the relationship between the content ratio of the initiator c and the line width of the wiring pattern.

Claims (12)

A photosensitive composition for producing a conductive layer including wiring having a line width of 30 μm or less, and The photosensitive composition includes a conductive powder, a photopolymerizable compound, and a photopolymerization initiator, The photopolymerization initiator contains at least The following two ingredients: (1) 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide; (2) α-amino alkyl phenones, When the entire photopolymerization initiator is set to 100% by mass, the (1) 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide accounts for 50% by mass or more. The photosensitive composition according to item 1 of the scope of patent application, wherein (1) 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide and (2) α- Aminoacetophenones have a mass ratio of 50:50 to 90:10. The photosensitive composition according to item 1 of the scope of patent application, wherein (1) 2,4,6-trimethylbenzylidene-diphenyl-phosphine oxide and (2) α- The mass ratio of the aminoacetophenones is 50:50 to 85:15. The photosensitive composition according to any one of claims 1 to 3 in the scope of patent application, wherein when the entire photosensitive composition is set to 100% by mass, the photopolymerization initiator The proportion is 2% by mass or less. The photosensitive composition according to any one of claims 1 to 3, wherein the photopolymerizable compound includes a photopolymerizable compound having a urethane bond. The photosensitive composition according to any one of claims 1 to 3, wherein the conductive powder includes silver-based particles. The photosensitive composition according to any one of claims 1 to 3, wherein the conductive powder includes core-shell particles, and the core-shell particles include a core portion including a metal material, and Covering at least a part of the surface of the core portion and including a covering portion of a ceramic material. The photosensitive composition according to any one of claims 1 to 3 in the scope of the patent application, wherein, in the L * a * b * color system based on Japanese Industrial Standard 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 3 of the patent application scope, further comprising an organic solvent having a boiling point of 150 ° C or higher and 250 ° C or lower. A complex including: Raw film; and The conductive film is disposed on the green sheet and includes a dried body of the photosensitive composition according to any one of claims 1 to 9 of the scope of patent application. An electronic part includes a conductive layer including the calcined body of the photosensitive composition according to any one of items 1 to 9 of the scope of patent application. An electronic component manufacturing method includes the steps of: applying the photosensitive composition according to any one of claims 1 to 9 on a substrate, and calcining after exposure and development to form a substrate containing the photosensitive composition. The conductive layer of the fired body of the photosensitive composition.