JP7213050B2 - ELECTRODE-FORMING RESIN COMPOSITION, CHIP TYPE ELECTRONIC COMPONENT, AND METHOD FOR MANUFACTURING THE SAME - Google Patents

Description

The present disclosure relates to an electrode-forming resin composition, a chip-type electronic component in which electrodes are formed using the electrode-forming resin composition, and a method for producing the same.
The present disclosure particularly relates to an electrode-forming resin composition for forming external electrodes of a surface-mounted chip-type electronic component, a chip-type electronic component using the same, and a method for manufacturing the same.

Chip-type electronic components such as chip inductors, chip resistors, chip-type multilayer ceramic capacitors, and chip-type thermistors include a chip-like element made of a ceramic sintered body, an internal electrode provided inside the element, and an electrical connection between the internal electrode. , and is mounted by soldering the external electrodes to the substrate.

In general, external electrodes are formed by applying a resin paste to the surface of a chip molded with a sealing resin, curing the paste to form a base electrode, and then plating the paste.

For forming the external electrodes, a resin paste is applied by a dipping method to the portions of the first end where the electrodes are to be formed, and pre-dried. Next, the external electrodes are formed by applying a resin paste to the portion where the second electrode is to be formed by dipping and pre-drying. The outer shape of the external electrode is formed by starting sintering of the low-temperature active silver fine particles by preliminary drying. After that, the thermosetting resin component is hardened by further heating to form the external electrodes that serve as the base for the plating process.

In such a chip-type electronic component, the external electrodes are for connecting the chip-type electronic component and the electric circuit on the substrate, so the quality depends on the electrical characteristics, reliability, mechanical characteristics, etc. of the product. have a significant impact on

In recent years, as the computerization of various products progresses, many chip-type electronic components are also being mounted in in-vehicle products, and these electronic components are expected to have higher environmental resistance and higher reliability than ever before. It's become demanded. Specifically, there is a demand for an electronic component that is stable with a small rate of change in resistance in environmental resistance tests.

For this reason, resin pastes for forming electrodes are also required to be excellent in adhesiveness and stability of electric resistance after moisture resistance treatment.

For example, Patent Document 1 discloses a method of forming a base electrode by sintering the metal powder in a resin paste obtained by kneading a metal powder such as Ag, an inorganic binder such as glass frit, and an organic vehicle. . Patent Document 2 discloses a method of forming a base electrode using a resin paste in which thermosetting resin such as epoxy resin and metal particles such as Ag are dispersed.

However, in the method of Patent Literature 1, heat treatment at a high temperature of 600° C. or higher is required, so there is a possibility that the resin in the sealing material or the self-adhesive film of the conductive wire may be deteriorated. In the method of Patent Document 2, when a moisture resistance test is performed, the adhesive strength between the element body and the external electrodes deteriorates, and there is a risk that the external electrodes may peel off.

Therefore, a method of firing at a low temperature of 250° C. or less using a resin paste containing fine metal particles with a sintering temperature of 250° C. or less has been disclosed (Patent Document 3).

JP-A-10-284343 JP-A-2005-116708 JP 2014-225590 A

However, simply using a resin paste containing metal fine particles not only results in a high volume resistance value, but also causes defects in the appearance of the coating, such as sharp corners and pinholes, and environmental resistance such as moisture absorption resistance tests and high temperature exposure tests. There was a risk that sufficient reliability could not be obtained for a high required level in the test (for example, the rate of change in resistance value should be within 10%).

Accordingly, the present disclosure provides a low-temperature sintering type electrode-forming resin composition that is excellent in adhesiveness, moisture resistance, stability of electrical resistance after heat treatment, and the like, and that is excellent in coating appearance. This electrode-forming resin composition can also be applied to in-vehicle level environmental resistance (super moisture resistance, super heat resistance).

The present disclosure finds that the resin used in the electrode-forming resin composition as a thermosetting resin is a combination of specific resins to satisfy the environmental resistance performance at the in-vehicle level. It has arrived.

That is, one aspect of the electrode-forming resin composition of the present disclosure includes (A) a thermosetting resin, (B) a radical initiator, (C) fine silver particles having a thickness or minor axis of 1 to 200 nm, (D) An electrode-forming resin composition containing silver powder having an average particle size of 2 to 20 μm other than the component (C), wherein the thixotropic ratio (ratio of viscosity at 2 rpm to viscosity at 20 rpm at 25° C. ) is between 1.1 and 2.0.

Further, in one aspect of the present disclosure, the (A) thermosetting resin includes (A1) a (meth)acrylic acid ester compound or (meth)acrylamide compound having a hydroxyl group, (A2) liquid at room temperature, Bismaleimide resin, (A3) polybutadiene, may be used. Furthermore, (E) a branched diol having 5 to 10 carbon atoms may be included as a solvent.

Further, in one aspect of the present disclosure, the 1% weight loss temperature for the cured product may be 280° C. or higher and 400° C. or lower, the lower limit may be 320° C. or higher, and the lower limit may be 340° C. or higher. and the lower limit may be 350° C. or higher.
When the 1% weight loss temperature is within this range, a stable electrode-forming resin composition having a small rate of change in resistance value in the moisture absorption resistance test and the high temperature storage resistance test can be obtained.
The 1% weight loss temperature can be controlled, for example, by adjusting the types and blending ratios of components contained in the electrode-forming resin composition.
In the present embodiment, for example, after curing 10 mg of the electrode-forming resin composition at 200° C. for 1 hour, TG/DTA (thermogravimetric/differential thermal analysis) was performed under the conditions of a nitrogen atmosphere or an air atmosphere and a temperature increase rate of 10° C./min. ), the 1% weight loss temperature of the electrode-forming resin composition can be measured.

One aspect of the chip-type electronic component of the present disclosure is a chip-type electronic component having a rectangular parallelepiped chip-type electronic component element made of a ceramic sintered body. Further, at least one of an internal electrode formed inside the chip-type electronic component element and an external electrode formed on an end surface of the chip-type electronic component element is a sintered body of the electrode-forming resin composition. be.

In one aspect of the method for manufacturing a chip-type electronic component of the present disclosure, a predetermined electrode pattern layer is formed by printing on the surface of a ceramic layer using the electrode-forming resin composition. The next step of the method for manufacturing a chip-type electronic component of the present disclosure is to place another ceramic layer on the electrode pattern layer, and apply the electrode-forming resin composition to the surface of the other ceramic layer. The operation of forming predetermined electrode pattern layers by printing is repeated to laminate ceramic layers and electrode pattern layers alternately. The final step of the method for manufacturing a chip-type electronic component of the present disclosure is to sinter the obtained laminate to obtain a chip-type electronic component element having internal electrodes formed by the electrode pattern, and An external electrode is formed on the end face of the electronic component element.

One aspect of the method for manufacturing a chip-type electronic component of the present disclosure is to apply the electrode-forming resin composition to an end face of a chip-type electronic component element by printing or dipping, and apply the electrode-forming resin composition. are sintered to form external electrodes.

The electrode-forming resin composition of the present disclosure has a small rate of change in resistance value in a moisture absorption resistance test and a high temperature storage resistance test. Furthermore, since silver fine particles are blended, sintering at a low temperature is possible, and the obtained sintered body is suitable for forming electrodes of electronic parts.

In addition, according to the chip-type electronic component and the manufacturing method thereof of the present disclosure, since the electrodes are formed using the electrode-forming resin composition, the bonding strength to the element is strong even in a high-humidity and high-heat environment. A chip-type electronic component having electrodes can be obtained, and a highly reliable product can be obtained.

One aspect of the electrode-forming resin composition of the present disclosure has the above configuration, and the disclosure will be described below with reference to an electrode-forming resin composition that is one embodiment.

The (A) thermosetting resin used in the present embodiment is not particularly limited, and may be a combination of a plurality of types of predetermined thermosetting resins. The resin used for this (A) thermosetting resin includes (A1) a (meth)acrylic acid ester compound or (meth)acrylamide compound having a hydroxyl group, (A2) a liquid at room temperature, and a fatty acid in the main chain. Bismaleimide resins having group hydrocarbon groups and (A3) polybutadiene resins may also be used.

The (A1) hydroxyl group-containing (meth)acrylic acid ester compound or (meth)acrylamide compound used in the present embodiment is a (meth)acrylate or (meth)acrylate having one or more (meth)acrylic groups in each molecule It is (meth)acrylamide and contains a hydroxyl group.

Here, a (meth)acrylate having a hydroxyl group can be obtained by reacting a polyol compound with (meth)acrylic acid or a derivative thereof. A known chemical reaction can be used for this reaction. A (meth)acrylate having a hydroxyl group is usually used in an acrylic acid ester or acrylic acid in an amount of 0.5 to 5 times the molar amount of the polyol compound.

A (meth)acrylamide having a hydroxyl group can be obtained by reacting an amine compound having a hydroxyl group with (meth)acrylic acid or a derivative thereof. In the method of producing (meth)acrylamides by reacting a (meth)acrylic acid ester with an amine compound, since the double bond of the (meth)acrylic acid ester is extremely reactive, amines, cyclopentadiene, alcohols, etc. is added to the double bond in advance as a protective group, and after the amidation is completed, the protective group is removed by heating.

By including hydroxyl groups in the (meth)acrylic acid ester compound or (meth)acrylamide compound, sinterability is promoted due to the reduction effect and adhesiveness is improved during electrode formation.

Moreover, the hydroxyl group referred to herein is an alcoholic group in which the hydrogen atom of an aliphatic hydrocarbon group is substituted. The content of this hydroxyl group may be from 1 to 50 in one molecule, and when the content of the hydroxyl group is within this range, there is no inhibition of sinterability due to excessive curing, and sinterability is promoted. can.

Examples of the (meth)acrylate compound or (meth)acrylamide compound having a hydroxyl group (A1) include compounds represented by the following general formulas (1) to (4).

（式中、Ｒ^１は水素原子又はメチル基を表し、Ｒ^２は炭素数１～１００の２価の脂肪族炭化水素基又は環状構造を持つ脂肪族炭化水素基を表す。）

(In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a divalent aliphatic hydrocarbon group having 1 to 100 carbon atoms or an aliphatic hydrocarbon group having a cyclic structure.)

（式中、Ｒ^１及びＲ^２はそれぞれ上記と同じものを表す。）

(In the formula, R ¹ and R ² each represent the same as above.)

（式中、Ｒ^１は上記と同じものを表し、ｎは１～５０の整数を表す。）

(Wherein, R ¹ represents the same as above, and n represents an integer of 1 to 50.)

（式中、Ｒ^１及びｎはそれぞれ上記と同じものを表す。）

(In the formula, R ¹ and n each represent the same as above.)

As the (A1) (meth)acrylic acid ester compound or (meth)acrylamide compound, the compounds represented by the above general formulas (1) to (4) can be used alone or in combination of two or more. . The carbon number of R ² in general formulas (1) and (2) may be from 1 to 100, or from 1 to 36. When the number of carbon atoms in ^R2 is within this range, the sinterability due to excessive curing is not impaired.

The (A2) bismaleimide resin used in the present embodiment, which is liquid at room temperature and has an aliphatic hydrocarbon group in its main chain, has an aliphatic hydrocarbon group having 1 or more carbon atoms in its main chain. The chain consists of two maleimide groups linked together. Here, the aliphatic hydrocarbon group may be linear, branched or cyclic, and may have 6 or more carbon atoms or 12 or more carbon atoms. The number may be 24 or more. Also, the aliphatic hydrocarbon group can be directly or indirectly bonded to the maleimide group, and may be directly bonded to the maleimide group.

（式中、Ｑは炭素数６以上の２価の直鎖状、分枝鎖状又は環状の脂肪族炭化水素基を示し、ＰはＯ、ＣＯ、ＣＯＯ、ＣＨ_２、Ｃ（ＣＨ_３）_２、Ｃ（ＣＦ_３）_２、Ｓ、Ｓ_２、ＳＯ及びＳＯ_２から選ばれる２価の原子又は有機基、或いは、これら原子又は有機基を少なくとも１つ以上含む有機基であり、ｍは１～１０の整数を表す。）であってもよい。 This (A2) maleimide resin is a compound represented by the following general formula (5)

(Wherein, Q represents a divalent linear, branched or cyclic aliphatic hydrocarbon group having 6 or more carbon atoms, P is O, CO, COO, CH ₂ , C(CH ₃ ) ₂ , C(CF ₃ ) ₂ , S, S ₂ , SO and SO ₂ , or an organic group containing at least one of these atoms or organic groups, and m is 1 to represents an integer of 10.).

Here, the divalent atom represented by P includes O, S, etc., and the divalent organic group includes CO, COO, CH ₂ , C(CH ₃ ) ₂ , C(CF ₃ ) ₂ , Examples include S ₂ , SO, SO ₂ and the like, and organic groups containing at least one or more of these atoms or organic groups. Examples of the organic group containing the above atoms or organic groups include those having a hydrocarbon group having 1 to 3 carbon atoms, a benzene ring, a cyclo ring, a urethane bond, etc. as structures other than the above. Groups represented by the following chemical formulas can be exemplified.

（式中、Ｒ^３～Ｒ^６は炭素数６以上の２価の直鎖状、分枝鎖状又は環状の脂肪族炭化水素基を示す）
なお、Ｒ^３～Ｒ^６は炭素数６～２０が好ましく、６～１２が好ましい。 Furthermore, (A2) the maleimide resin may be a bismaleimide resin that is liquid at room temperature and represented by the following general formula (6).

(Wherein, R ³ to R ⁶ represent a divalent linear, branched or cyclic aliphatic hydrocarbon group having 6 or more carbon atoms)
R ³ to R ⁶ preferably have 6 to 20 carbon atoms, preferably 6 to 12 carbon atoms.

In the present embodiment, a bismaleimide resin having an aliphatic hydrocarbon group in the main chain is used as the bismaleimide resin (A2) to provide excellent heat resistance, low stress, and good hot adhesive strength after moisture absorption. This is one of the requirements for obtaining an electrode-forming resin composition. In order to effectively obtain this property, it is preferable to use, as the component (A2), a bismaleimide resin which is imide-extended with an aliphatic hydrocarbon group represented by the general formula (5) and which is liquid at room temperature.

The (A2) bismaleimide resin may have a polystyrene equivalent number average molecular weight of 500 or more and 10,000 or less, or 500 or more and 5,000 or less. When the number average molecular weight is in this range, the moisture absorption resistance is excellent, and the adhesive strength under heat can be increased. If the number average molecular weight is less than 500, the flexibility and heat resistance are lowered. If the number average molecular weight exceeds 10,000, the workability in preparing the composition and the workability in use will tend to deteriorate.

(A3) polybutadiene used in the present embodiment is a polymer obtained by polymerizing 1,3-butadiene, and includes partially modified compounds thereof. This (A3) polybutadiene may be (A31) a compound obtained by modifying polybutadiene with epoxy, or (A32) a polybutadiene polymer having (meth)acryloyl groups at its terminals.

(A31) The compound obtained by modifying polybutadiene with epoxy may be epoxidized polybutadiene having an epoxy equivalent of 50 to 500 (g/eq). If the epoxy equivalent is less than 50, the viscosity tends to increase and the workability of the resin composition tends to decrease, and if it exceeds 500, the adhesive strength when hot tends to decrease. The epoxy equivalent is obtained by the perchloric acid method. As this epoxidized polybutadiene, one having a hydroxyl group in the molecule may be used. Examples of epoxidized polybutadiene include Epolead PB4700 and GT401 (both trade names) marketed by Daicel Corporation, JP-100 and JP-200 (both trade names) marketed by Nippon Soda Co., Ltd., can be used.

(A32) A polybutadiene polymer having a (meth)acryloyl group at its terminal can be obtained by a urethanization reaction between a polybutadiene polymer having a hydroxyl group introduced at its molecular terminal and 2-(meth)acryloyloxyethyl isocyanate or the like. Alternatively, it can also be obtained by reacting a polybutadiene polymer having a hydroxyl group introduced at its molecular end with a diisocyanate such as hexamethylene diisocyanate and then reacting it with (meth)acrylic acid.

Examples of the polybutadiene polymer having a (meth)acryloyl group at the end include BAC-15, BAC-45 and SPBDA-S30 (all trade names) available from Osaka Organic Chemical Industry, and available from Nippon Soda Co., Ltd. can be used.
By containing (A3) polybutadiene, the electrode-forming resin composition can improve the adhesiveness of the electrode to the chip part terminal.

This (A3) polybutadiene may have a number average molecular weight of 500 to 10,000. When the molecular weight is in this range, the adhesiveness is good, and the viscosity can be controlled to an appropriate level, resulting in good workability. The number average molecular weight is a value measured by gel permeation chromatography using a standard polystyrene calibration curve (hereinafter referred to as GPC method).

The components (A1) to (A3) described above may be blended in predetermined amounts as described below to form (A) a thermosetting resin.
That is, the (A) thermosetting resin used in the present embodiment is, when the (A) thermosetting resin is 100% by mass, has (A1) a hydroxyl group, a (meth) acrylic acid ester compound or (meth) ) 0 to 75% by mass of an acrylamide compound, (A2) 10 to 90% by mass of a bismaleimide resin that is liquid at room temperature and has an aliphatic hydrocarbon group in the main chain, and (A3) 10 to 90% by mass of epoxidized polybutadiene. %.

Further, (A1) the (meth)acrylate compound or (meth)acrylamide compound having a hydroxyl group may be 0 to 50% by mass.
Furthermore, (A1) the (meth)acrylic acid ester compound or (meth)acrylamide compound having a hydroxyl group may be 20% by mass or less, or may be 0% by mass. (A1) When the (meth)acrylic acid ester compound or (meth)acrylamide compound having a hydroxyl group is 0% by mass, (A2) relative to the blending amount of (A3) epoxidized polybutadiene is liquid at room temperature, and the main chain The ratio [(A2)/(A3)] of the amount of the bismaleimide resin having an aliphatic hydrocarbon group may be 1 or more.
When each component of (A1) to (A3) is within this range, the heat resistance, moisture resistance and adhesion are good, and the required level of environmental resistance such as moisture absorption resistance test and high temperature exposure test is particularly high. It can be used for high in-vehicle applications.

If the amount of component (A1) is more than 75% by mass, the electrode-forming resin composition may have poor heat resistance and moisture resistance. If the amount of the component (A2) is less than 10% by mass, the heat resistance and moisture resistance of the electrode-forming resin composition will be poor, and if it is more than 90% by mass, the adhesive strength of the electrode-forming resin composition will be poor. There is a risk. If the amount of the component (A3) is less than 10% by mass, the adhesive strength of the electrode-forming resin composition is poor, and if it is more than 90% by mass, unreacted components of the electrode-forming resin composition tend to remain. There is a possibility that adhesive strength will be inferior.

As the thermosetting resin (A), thermosetting resins other than the above components (A1) to (A3) can also be used. Thermosetting resins that can be used here include, for example, epoxy resins. , bismaleimide resin, polybutadiene resin, phenol resin, and the like. However, the thermosetting resin other than the components (A1) to (A3) may be 20% by mass or less, or 10% by mass or less, when the (A) thermosetting resin is 100% by mass. good too.

The (B) radical initiator used in the present embodiment can be used without particular limitation as long as it is a polymerization catalyst that is usually used for radical polymerization.

The (B) radical initiator has a decomposition initiation temperature of 40 to 140° C. in a rapid heating test (measurement test of decomposition initiation temperature when 1 g of a sample is placed on an electric heating plate and heated at 4° C./min). It may be If the decomposition initiation temperature is less than 40°C, the storage stability of the adhesive thermosetting resin composition at room temperature may be poor, and if it exceeds 140°C, the curing time may become extremely long. The decomposition initiation temperature is defined as the temperature at which the mass of the sample decreases by 1% with respect to the mass before heating.

Specific examples of radical initiators satisfying this condition include 1,1-bis(t-butylperoxy)-2-methylcyclohexane, t-butylperoxyneodecanoate, and dicumyl peroxide. be done. These may be used alone or in combination of two or more to control curability.

The amount of the radical initiator (B) to be blended may be 0.1 to 10 parts by mass with respect to 100 parts by mass of the thermosetting resin (A). If the blending amount exceeds 10 parts by mass, the viscosity of the resin composition may change significantly over time, resulting in deterioration in workability.

The fine silver particles (C) used in this embodiment can be used without any particular limitation as long as they have a thickness or minor axis of 1 to 200 nm. The shape of the (C) fine silver particles may be plate-shaped, dendritic, rod-shaped, wire-shaped, or spherical. Here, in the case of a plate type, the thickness thereof, and in the case of a dendritic, rod-like, wire-like, or spherical shape, the shortest cross-sectional diameter thereof should satisfy the above range.

The (C) fine silver particles may be (C1) plate-type fine silver particles. Since the plate-shaped fine silver particles tend to pile up in the direction of the minor axis, when the electrode-forming resin composition is dip-coated on both ends of the electronic component, the advantage is that a smooth electrode surface can be obtained with little unevenness on the surface. There is

The plate-shaped fine silver particles may have a central particle diameter of 0.3 to 15 μm. An embodiment of the present disclosure can improve the dispersibility in the resin component by setting the median particle size of the plate-shaped fine silver particles within this range. Here, the median particle size refers to the 50% integrated value (50% particle size) in the volume-based particle size distribution curve obtained by measuring with a laser diffraction particle size distribution analyzer.

Also, the thickness is 10 to 200 nm, and may be 10 to 100 nm. This thickness is measured by data processing of observation images acquired by a transmission electron microscope (TEM) or a scanning electron microscope (SEM). Furthermore, the average thickness of this thickness may be within the above range. This average thickness is calculated as a number average thickness as follows.

The thickness measured from [n+1] (n+1 is, for example, about 50 to 100) observed images of the plate-type fine silver particles are arranged in order from thickest to thinnest, and the range (maximum thickness: x ₁ , minimum Thickness: x _n+1 ) is divided into n sections, and each thickness section is set to [x _j , x _j+1 ] (j=1, 2, . . . , n). The division in this case is equal division on a logarithmic scale. Also, the representative thickness in each thickness section is represented by the following formula based on the logarithmic scale.

Furthermore, let r _j ( _{j =} 1, 2, . The average value μ above can be calculated by the following formula.

Since this μ is a numerical value on a logarithmic scale and does not have units for thickness, 10 ^μ , ie, 10 to the power of μ, is calculated to return to units for thickness. This 10 ^μm is the number average thickness.

Further, the long side in the direction perpendicular to the thickness direction may be in the range of 8 to 150 times the thickness, or may be 10 to 50 times the thickness. Furthermore, the short side in the direction perpendicular to the thickness direction may be within the range of 1 to 100 times the thickness, or may be 3 to 50 times the thickness.

The plate-type fine silver particles can be self-sintered at 100 to 250.degree. By containing silver fine particles that self-sinter at 100 to 250 ° C. in this way, the fluidity of the silver fine particles is improved during heat curing, and as a result, the number of contacts between the silver fine particles increases, and the contact area increases. becomes large, and the conductivity is remarkably improved. Since the lower the self-sintering temperature, the better the sinterability, the sintering temperature of the plate-shaped fine silver particles may be 100 to 200.degree. Here, the term "self-sinterable" means that the material can be sintered by heating at a temperature lower than the melting point without applying pressure or adding additives.

Examples of such plate-type fine silver particles include M612 manufactured by Tokusen Kogyo Co., Ltd. (trade name; central particle size: 6 to 12 μm, particle thickness: 60 to 100 nm, melting point: 250° C.), M27 (trade name: central particle size: 2 ~7 μm, particle thickness 60-100 nm, melting point 200° C.), M13 (trade name; median particle size 1-3 μm, particle thickness 40-60 nm, melting point 200° C.), N300 (trade name; median particle size 0.3-0 .6 μm, a particle thickness of 50 nm or less, and a melting point of 150° C.). These plate-type fine silver particles may be used alone or in combination. In particular, in order to improve the filling rate, the plate-shaped fine silver particles are used, for example, by combining relatively large silver fine particles such as M27 and M13 among the above-mentioned plate-shaped silver fine particles with small particle diameter ones such as N300. may

(C1) Plate-type fine silver particles preferably have a particle thickness of 200 nm or less, a tap density (TD) of 3.0 to 7.0 g/cm ³ and a specific surface area (BET) of 2.0 to 6.0 m ² /g.

The (C) fine silver particles may be (C2) spherical fine silver particles. The spherical fine silver particles used in this embodiment may have a particle diameter of 10 to 200 nm. The spherical silver fine particles are generally provided with a coating layer of an organic compound on the metal surface of the silver fine particles, or are made by dispersing the silver fine particles in an organic compound. With such a form, the metal surfaces of the contained silver fine particles can be prevented from coming into direct contact with each other, so that the formation of agglomerates of the silver fine particles can be reduced, and the silver fine particles are dispersed individually. can be held with In addition, this particle diameter is measured by data-processing the observed image acquired with a transmission electron microscope (TEM) or a scanning electron microscope (SEM). Furthermore, the average particle size of (C2) the spherical fine silver particles may be within the above range. This average particle size is calculated as a number average particle size of particle sizes measured from 50 to 100 observation images of the spherical silver fine particles. The average value of the number average particle diameter may be calculated in the same manner as the calculation of the average thickness.

The above (C1) plate-like fine silver particles and (C2) spherical silver fine particles may be used in combination, and when used in combination, the compounding ratio may be 100:0 to 10:90. When the compounding ratio of (C1) the plate-like fine silver particles and (C2) the spherical silver fine particles is within this range, the coating appearance and fixing strength are good.

The (D) silver powder used in this embodiment is a silver powder other than the (C) component.
(D) The silver powder has an average particle size of 0.2 to 20 μm, and may be silver powder as an inorganic filler added to impart electrical conductivity to the resin adhesive. In this embodiment, (D) the silver powder may have a tap density of 2.0 to 7.0 g/cm ³ .

By adding the silver powder of the component (D) in addition to the fine silver particles of the component (C), the bonding strength between the terminal and the electrode of the chip component can be further improved. Further, examples of the shape of the silver particles used here include flake-like, resin-like, rod-like, wire-like, spherical, and plate-like shapes. The average particle size of the component (D) silver powder refers to the 50% integrated value (50% particle size) in the volume-based particle size distribution curve obtained by measuring with a laser diffraction particle size distribution analyzer. Among them, (D1) good conduction resistance can be obtained by using flaky silver powder. Furthermore, silver powder of component (D) may be used by mixing (D1) flaky silver powder and (D2) spherical silver powder. The mixing ratio of (D1) flaky silver powder and (D2) spherical silver powder may be 100:0 to 10:90. When the blending ratio of (D1) flaky silver powder and (D2) spherical silver powder is in this range, the fixing strength and conduction resistance are good.

As for the ratio of these components (C) and (D), the mass ratio of component (C):component (D) may be 10:90 to 50:50. If the ratio of component (C) to component (D) is too small, the sinterability will decrease, resulting in an increase in the resistance value. It may be damaged.

The electrode-forming resin composition of the present embodiment essentially comprises the above components (A) to (D), and the electrode-forming resin composition thus obtained has a thixotropic ratio (2 rpm at 25° C. The ratio of the viscosity to the viscosity at 20 rpm) is 1.1 to 2.0. This thixotropic ratio may be between 1.1 and 1.5, or between 1.2 and 1.4.
When the thixotropic ratio is in the range of 1.1 to 2.0, the coated appearance is excellent, and the adhesion, moisture resistance, stability of electrical resistance after heat treatment, and the like are excellent. On the other hand, if the thixotropic ratio is less than 1.1, there is a risk that workability will be reduced due to stringiness during dip coating in the manufacture of electronic parts. When it is used as an external electrode, there is a possibility that the dimensional stability may be lowered due to the formation of sharp corners.

In the present embodiment, the electrode molding resin composition may further contain (E) a high-viscosity solvent having a viscosity of 200 cP or more as a solvent. The viscosity of this (E) solvent may be 250 cP or more, or 300 cP or more. Such a high-viscosity solvent may be, for example, a diol having a hydrocarbon skeleton as a main chain, or a branched diol having 5 to 10 carbon atoms. The viscosity of the solvent (E) may be 600 cP or less, or 500 cP or less.
By containing such a (E) solvent, it becomes easy to adjust to the said thixotropic ratio.

As the diol having a hydrocarbon skeleton as a main chain, various known diols can be used without particular limitation. Such a diol may be a branched diol having 5 to 10 carbon atoms in total, and may be a 2-alkyl-1,3-hexanediol having an alkyl group having 1 to 4 carbon atoms as a substituent. good too. Specific compounds of molecular chain diols include, for example, 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5- Examples include pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-methyl-1,8-octanediol, neopentyl glycol, etc. Two or more of these may be used in combination. Among these, those having a boiling point of about 140 to 260°C are preferable.
In particular, at least one selected from the group consisting of 2-ethyl-1,3-hexanediol, 2-butyl-2-ethyl-1,3-propanediol and 2,4-diethyl-1,5-pentanediol is preferred. .
As the 2-alkyl-1,3-hexanediol having an alkyl group having 1 to 4 carbon atoms as a substituent, specific examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and the like. mentioned.

For example, 2-ethyl-1,3-hexanediol has a high viscosity of 323 cP at 20°C. When such a high-viscosity solvent is used in a normal electrode paste, the viscosity may be too high and the printability and workability may be deteriorated. On the other hand, when the solvent (E) is used in the electrode paste of the present embodiment, the desired thixotropic ratio can be obtained even if the concentrations of (C) silver fine particles and (D) silver powder are specified in the present embodiment. is obtained, and an electrode having a good coating appearance is obtained.

Furthermore, since the electrode-forming resin composition contains the solvent, in the manufacturing process of electronic parts, when the electrode-forming resin composition is dip-coated and the surface of the dip tank is flattened with a squeegee, the electrode formation The viscosity change rate (viscosity increase rate) of the resin composition for use becomes 200% or less, and continuous workability becomes good.

In the electrode-forming resin composition of the present embodiment, when the above-described components (A) to (D) are 100% by mass in total, (A) a thermosetting resin 1 to 15% by mass, (C) 5 to 40% by mass of fine silver particles, (D) 50 to 90% by mass of silver powder, (B) a radical initiator (A) per 100 parts by mass of thermosetting resin 0.1 to 10 parts by mass can be blended. In addition, when the solvent (E) is contained, the content of the solvent (E) is 1 to 10 parts by mass when the total of the components (A) to (D) is 100 parts by mass. good too. With such a blend, heat resistance, moisture resistance, adhesiveness, and environmental resistance are improved.

The electrode-forming resin composition of the present embodiment contains the above components (A) to (D), but in addition to these components, if necessary, (E) a solvent and other resin compositions of this type can be added. Addition of curing accelerators, rubber, stress reducing agents such as silicone, coupling agents, adhesion promoters, titanate coupling agents, pigments, dyes, antifoaming agents, surfactants, diluents, etc. Agents can be blended as appropriate.

The electrode-forming resin composition of the present embodiment is obtained by sufficiently mixing each of the above components (A) to (D), additives such as a coupling agent that are blended as necessary, and (E) a solvent. .
Next, the electrode-forming resin composition of the present embodiment is kneaded with a disperse, a kneader, a three-roll mill, or the like. Finally, the electrode-forming resin composition of the present embodiment can be prepared by defoaming the kneaded resin composition.

The electrode-forming resin composition thus obtained can be used for forming electrodes of electric/electronic parts, etc., and its thixotropic ratio (the ratio of the viscosity at 2 rpm to the viscosity at 20 rpm at 25° C.) is 1.1. ~2.0, 1.1 to 1.5, or 1.2 to 1.4. When the thixotropic ratio is within this range, the coated appearance is excellent, and the adhesion, moisture resistance, stability of electrical resistance after heat treatment, and the like are excellent.

If the thixotropic ratio is less than 1.1, there is a risk of inducing a reduction in workability due to stringiness during dip coating in the manufacture of electronic parts. When it is used as an electrode, there is a possibility that sharp corners may occur and the dimensional stability may decrease, and in either case, the yield as an electronic component may deteriorate.

Further, the film thickness of the cured product of the electrode-forming resin composition formed as the external electrode of the electronic component may be 5 to 100 μm. If the film thickness is less than 5 μm, the coating property on the intended part is poor and the uniformity of the coating film is lacking, and pinholes are generated.

In the manufacturing process of electronic parts, the surface of the dip tank is flattened by a squeegee when the electrode-forming resin composition is dip-coated. viscosity) is required to be 200% or less.

The electrode-forming resin composition of the present embodiment obtained in this way has excellent environmental resistance performance (super moisture resistance, super heat resistance), high thermal conductivity, and heat dissipation at the level of in-vehicle parts. becomes. Therefore, when an internal electrode or an external electrode of an electronic component is formed using this electrode-forming resin composition, remarkable improvement in characteristics is observed. For example, when it is used as an external electrode of an inductor, it forms a direct metallic bond with the coil, and it is possible to express high bonding strength with the base body other than the coil due to the resin adhesive strength. It can contribute to the improvement of reliability in

Next, the chip-type electronic component of this embodiment and the manufacturing method thereof will be described.
The chip-type electronic component of the present embodiment is a chip-type electronic component having a rectangular parallelepiped chip-type electronic component element body made of a ceramic sintered body, and internal electrodes and internal electrodes formed inside the chip-type electronic component element body. At least one of the external electrodes formed on the end face of the chip-type electronic component element is a sintered body of the electrode-forming resin composition of the above embodiment. The volume resistivity of the sintered body obtained at this time is preferably 1×10 ⁻⁴ Ω·cm or less. Furthermore, the lower the volume resistivity, the better the properties as an electronic component, so the volume resistivity may be 1×10 ⁻⁵ Ω·cm or less. If the volume resistivity exceeds 1×10 ⁻⁴ Ω·cm, sintering is not sufficient, which may lead to deterioration in product reliability.

In manufacturing the chip-type electronic component of the present embodiment, a predetermined electrode pattern layer is formed on the surface of the ceramic layer by printing using the electrode-forming resin composition of the present embodiment.
The next step of the method for manufacturing the chip-type electronic component of the present embodiment is to place another ceramic layer on the electrode pattern layer, and to coat the surface of the other ceramic layer with the electrode-forming resin of the present embodiment. The operation of forming predetermined electrode pattern layers by printing using the composition is repeated to laminate ceramic layers and electrode pattern layers alternately.

The next step in the method for manufacturing a chip-type electronic component according to the present embodiment is to sinter the obtained laminate to obtain a chip-type electronic component element having internal electrodes formed by electrode patterns.
The final step of the manufacturing method of the chip-type electronic component according to the present embodiment is to form external electrodes on the end face of the chip-type electronic component element to obtain the chip-type electronic component. At this time, the external electrodes can be formed using a known electrode-forming resin composition, but the electrode-forming resin composition of the present embodiment may also be used.

In manufacturing the other chip-type electronic component of the present embodiment, the electrode-forming resin composition of the present embodiment is applied by printing or dipping to the end face of the chip-type electronic component element, and the coated electrode-forming resin composition is External electrodes are formed by sintering the resin composition to obtain a chip-type electronic component.
At this time, in the present embodiment, the electrode-forming resin composition can be sintered by conventional heating, and even when sintered at 100 to 300° C., sufficient conductivity can be ensured. In addition, this electrode-forming resin composition has good continuous workability during dip coating, and can efficiently form electrodes.

EXAMPLES Next, the present embodiment will be described in more detail with reference to Examples, but the present embodiment is not limited to these Examples.

(Examples 1-12, Comparative Examples 1-4)
Each component was mixed according to the formulations shown in Tables 1 to 3 and kneaded with a roll to obtain an electrode-forming resin composition. In Tables 1 to 3, the blending amount of each component is expressed in parts by mass. The obtained resin compositions were evaluated by the following methods. The results are also shown in Tables 1-3. The materials used in Examples and Comparative Examples had the following characteristics.

[(A) Component]
(A1) acrylic resin: hydroxyl ethyl acrylamide (manufactured by Kohjin Co., Ltd., trade name: HEAA)
(A21) Imido-extended bismaleimide (manufactured by Designer Molecules, trade name: BMI-1500; number average molecular weight: 1500)
(A22) Imido-extended bismaleimide (manufactured by Designer Molecules, trade name: BMI-689; number average molecular weight 689)
(A31) Epoxidized polybutadiene resin (manufactured by Nippon Soda Co., Ltd., trade name: JP-200)
(A32) acrylate-terminated polybutadiene resin (manufactured by Nippon Soda Co., Ltd., trade name: TE-2000)

Thermosetting resin other than (A1) to (A3) Epoxy resin: Bisphenol F type liquid epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: YL983U)
Phenolic resin: Bisphenol F (manufactured by Honshu Chemical Industry Co., Ltd., trade name: Bisphenol F)

[(B) Component]
Radical initiator: dicumyl peroxide (manufactured by NOF Corporation, trade name: Permil D; decomposition temperature in rapid heating test: 126°C)

[(C) component]
Plate-type fine silver particles (manufactured by Tokusen Kogyo Co., Ltd., trade name: M13; central particle diameter: 2 μm, thickness: 50 nm or less)
Spherical silver fine particles (manufactured by DOWA Electronics Co., Ltd., trade name: Ag nano powder-1; average particle size: 20 nm)

[(D) Component]
Silver powder A (shape: flaky, average particle size: 4.0 μm, thickness: 0.3 μm or more, tap density: 5.5 g/cm ³ )
Silver powder B (shape: flaky, average particle size: 3.0 μm, thickness: 0.3 μm or more, tap density: 3.8 g/cm ³ )
Silver powder C (shape: spherical, average particle size: 2.4 μm, tap density: 5.0 g/cm ³ )

[(E) component]
Solvent: 2-ethyl-1,3-hexanediol (manufactured by Tokyo Chemical Industry Co., Ltd.)
[Other ingredients]
Dilution solvent: butyl carbitol (manufactured by Tokyo Chemical Industry Co., Ltd.)
Curing accelerator: 1-benzyl-2-phenylimidazole (manufactured by Shikoku Chemical Industry Co., Ltd., trade name: 1B2PZ)
Additive: Silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-503)

<Evaluation method>
[viscosity]
The value at 25° C. and 2 rpm was measured using an E-type viscometer (3° cone).
[Thixotropy]
Using an E-type viscometer (3° cone), the viscosity at 2 rpm and 20 rpm was measured at 25° C., and the ratio of the viscosity at 2 rpm to 20 rpm (viscosity at 2 rpm/viscosity at 20 rpm) was defined as the thixotropic ratio.

[Volume resistivity]
The electrode-forming resin composition was applied to a glass substrate (thickness 1 mm) by screen printing in a size of 5 mm×50 mm and 30 μm thick, and cured at 200° C. for 60 minutes. The electric resistance of the obtained wiring was measured by the four-probe method using the product name "MCP-T600" (manufactured by Mitsubishi Chemical Corporation).

[Coating Appearance]
An electrode-forming resin composition was formed on both ends of a chip-type electronic component element by dip coating, and heat-cured at 200° C. for 60 minutes to obtain an electronic component. The electronic parts obtained at this time were evaluated as NG when dimensional stability could not be obtained due to steps of the electrode-forming resin composition or the like. Whether or not dimensional stability can be obtained is determined by observing the cross section of the electrode with a microscope. Those exceeding were judged to be "defective".

[1% weight loss temperature]
After curing 10 mg of the electrode-forming resin composition obtained in each example and each comparative example at 200° C. for 1 hour, a TG/DTA7200 thermogravimetric analyzer (manufactured by SII Nanotechnology Co., Ltd.) was used as a measuring device. Then, while flowing compressed air, the sample was heated from room temperature (25° C.) to 600° C. at a rate of 10° C./min, and the temperature at which the weight of the used sample decreased by 1% was measured.
[Hardened product water absorption]
Using a cured product with a film thickness of 200 μm and a size of 500 mm square, the weight was measured after leaving it in a high-temperature, constant-humidity chamber at 85° C. and 85% for 168 hours based on the initial weight.

[Fixation strength]
The electrode-forming resin composition was applied to both ends of the chip-type electronic component by dip coating, and heat-cured at 200° C. for 60 minutes. This was plated with Ni and Sn and mounted on a substrate by soldering to produce an electronic component. The electronic component was laterally pushed at a rate of 20 mm/min to measure the shear strength, and the load at which the component broke was taken as the bond strength (N).

[Resistance value change rate 1 after heat resistance current test]
The electrode-forming resin composition was applied to both ends of the chip-type electronic component by dip coating, and heat-cured at 200° C. for 60 minutes. This was plated with Ni and Sn and mounted on a substrate by soldering to produce an electronic component.
The electronic component is placed in a constant temperature bath (temperature 150 ° C.), and a current test (1 A) is performed in this state. value was calculated.

[Resistance value change rate 2 after humidity resistance current test]
The electrode-forming resin composition was applied to both ends of the chip-type electronic component by dip coating, and heat-cured at 200° C. for 60 minutes. This was plated with Ni and Sn and mounted on a substrate by soldering to produce an electronic component.

Put the electronic component in a constant temperature and humidity chamber (temperature 85 ° C., humidity 85%), conduct a current test (1A) in this state, after 500 hours, after 1000 hours, after 2000 hours, after 3000 hours A relative value to the later initial value was calculated.

From the above results, it was found that an electronic component using the electrode-forming resin composition of the present embodiment is excellent in all characteristics and highly reliable.

Claims (11)

(A) a thermosetting resin, (B) a radical initiator, (C) fine silver particles having a thickness or minor diameter of 1 to 200 nm, and (D) components other than the component (C) having an average particle size of 2 to An electrode-forming resin composition comprising 20 μm silver powder,
Its thixotropic ratio (ratio of viscosity at 2 rpm to viscosity at 20 rpm at 25° C.) is 1.1 to 2.0 ,
The electrode-forming resin composition further comprises (E) a branched-chain diol having 5 to 10 carbon atoms as a solvent . The (A) thermosetting resin comprises (A1) a (meth)acrylic acid ester compound or (meth)acrylamide compound having a hydroxyl group, (A2) a bismaleimide resin that is liquid at room temperature, and (A3) polybutadiene. 2. The electrode-forming resin composition according to claim 1 , comprising at least one selected. The (A) thermosetting resin contains the (A1) hydroxyl group-containing (meth)acrylic acid ester compound or (meth)acrylamide compound in an amount of 0 to 75% by mass, and the (A2) bismaleimide resin in an amount of 10 to 90% by mass. 3. The electrode-forming resin composition according to claim 2 , wherein the (A3) polybutadiene is blended at a ratio of 10 to 90% by mass. The (A1) (meth)acrylic acid ester compound or (meth)acrylamide compound is a compound selected from the following general formulas (1) to (4)

(In the formula, R ¹ represents a hydrogen atom or a methyl group, and R ² represents a divalent aliphatic hydrocarbon group having 1 to 100 carbon atoms or an aliphatic hydrocarbon group having a cyclic structure.)

(In the formula, R ¹ and R ² each represent the same as above.)

(Wherein, R ¹ represents the same as above, and n represents an integer of 1 to 50.)

(In the formula, R ¹ and n each represent the same as above.)
4. The electrode-forming resin composition according to claim 2 , which is an acrylic resin containing at least one of (A2) the bismaleimide resin is a compound represented by the following general formula (5) or (6)

(Wherein, Q represents a divalent linear, branched or cyclic aliphatic hydrocarbon group having 6 or more carbon atoms, P is O, CO, COO, CH ₂ , C(CH ₃ ) ₂ , C(CF ₃ ) ₂ , S, S ₂ , SO and SO ₂ , or an organic group containing at least one of these atoms or organic groups, and m is 1 to represents an integer of 10.)

(wherein R ³ to R ⁶ represent a divalent linear, branched or cyclic aliphatic hydrocarbon group having 6 or more carbon atoms). The electrode-forming resin composition according to 1. When the total of the components (A) to (D) is 100% by mass, the (A) thermosetting resin is 1 to 15% by mass, the (C) silver fine particles is 5 to 40% by mass, and the (D) ) 50 to 90% by mass of silver powder, and 0.1 to 10 parts by mass of the (B) radical initiator with respect to 100 parts by mass of the (A) thermosetting resin. 6. The electrode-forming resin composition according to any one of 5 . 7. The composition according to any one of claims 1 to 6 , wherein the component (E) is contained in an amount of 1 to 10 parts by mass when the total of the components (A) to (D) is 100 parts by mass. The resin composition for electrode formation of. At least one of an internal electrode positioned inside a chip-type electronic component having a rectangular parallelepiped chip-type electronic component element body made of a ceramic sintered body and an external electrode positioned on an end face of the chip-type electronic component element body 8. A chip-type electronic component comprising a sintered body of the electrode-forming resin composition according to any one of 1 to 7 . A predetermined electrode pattern layer is printed on the surface of the ceramic layer using the electrode-forming resin composition according to any one of claims 1 to 7 ,
Further, another ceramic layer is placed on the electrode pattern layer, and the electrode-forming resin composition according to any one of claims 1 to 6 is applied to the surface of the other ceramic layer. Repeat the operation of printing the electrode pattern layer of to alternately laminate the ceramic layer and the electrode pattern layer,
By sintering the obtained laminate, a chip-type electronic component element having internal electrodes formed by the electrode pattern layers is obtained,
A method of manufacturing a chip-type electronic component, comprising forming an external electrode on an end face of the chip-type electronic component element. The external electrodes are formed by applying the electrode-forming resin composition according to any one of claims 1 to 7 to the end face of the chip-type electronic component element by printing or dipping. 10. The method of manufacturing a chip-type electronic component according to claim 9, wherein the electrode-forming resin composition is sintered. The electrode-forming resin composition according to any one of claims 1 to 7 is applied by printing or dipping onto the end face of the chip-type electronic component element,
A method for producing a chip-type electronic component, comprising forming an external electrode by sintering the applied electrode-forming resin composition.