阅读说明：本技术 电子组件及制造该电子组件的方法 (Electronic component and method of manufacturing the same ) 是由 具根会 金成珍 具本锡 于 2020-11-24 设计创作，主要内容包括：本公开提供一种电子组件及制造该电子组件的方法,所述电子组件包括主体和外电极,所述主体包括介电层和内电极,所述外电极包括设置在所述主体上的导电树脂层以及设置在所述导电树脂层上的镀层。所述导电树脂层包括金属颗粒、第一金属间化合物和基体树脂,并且第二金属间化合物设置在所述导电树脂层与所述镀层之间的边界上。(An electronic assembly includes a main body including a dielectric layer and an inner electrode, and an outer electrode including a conductive resin layer disposed on the main body and a plating layer disposed on the conductive resin layer. The conductive resin layer includes metal particles, a first intermetallic compound, and a matrix resin, and a second intermetallic compound is disposed on a boundary between the conductive resin layer and the plating layer.)

1. An electronic assembly, comprising:

a body including a dielectric layer and an internal electrode; and

an external electrode including a conductive resin layer disposed on the body and a plating layer disposed on the conductive resin layer,

wherein the conductive resin layer includes metal particles, a first intermetallic compound, and a matrix resin, and

the conductive resin layer further includes a second intermetallic compound disposed on a boundary between the conductive resin layer and the plating layer.

2. The electronic component according to claim 1, wherein the first intermetallic compound includes an intermetallic compound in a solid state between an element of the low melting point metal and an element of the metal particle, and

the second intermetallic compound includes an intermetallic compound in a solid state between an element of the low melting point metal and a metal included in the plating layer.

3. The electronic component according to claim 2, wherein the low melting point metal has a melting point of 300 ℃ or less.

4. The electronic assembly of claim 2, wherein the low melting point metal comprises one or more metals selected from Sn, and combinations thereof_96.5Ag_3.0Cu_0.5、Sn₄₂Bi₅₈And Sn₇₂Bi₂₈At least one of the choices.

5. The electronic assembly of claim 1, wherein the metal particles comprise at least one of Ag and Cu, and

the first intermetallic compound comprises Ag₃Sn、Cu₆Sn₅And Cu₃Sn.

6. The electronic component of claim 1, wherein the second intermetallic compound comprises a Ni-Sn intermetallic compound.

7. The electronic component according to claim 1, wherein the second intermetallic compound is provided on a boundary between the first intermetallic compound and the plating layer.

8. The electronic assembly according to any one of claims 1 to 7, wherein an electrode layer comprising a conductive metal and glass is additionally provided between the conductive resin layer and the main body.

9. The electronic assembly of any of claims 1-7, further comprising:

an additional plating layer disposed on the plating layer.

10. A method for manufacturing an electronic assembly, the method comprising:

preparing a body including a dielectric layer and an inner electrode;

applying a paste for a conductive resin layer to the body, drying the applied paste, and then performing a curing heat treatment to form a conductive resin layer; and

plating a metal material on the conductive resin layer, and then performing a plating heat treatment to form a plated layer,

wherein the paste for the conductive resin layer includes a metal powder coated with a first organic material, a low melting point metal powder coated with a second organic material, and a matrix resin.

11. The method of claim 10, wherein each of the first and second organic materials comprises a fatty acid-based organic material.

12. The method of claim 10, wherein the low melting metal of the low melting metal powder has a melting point of 300 ℃ or less.

13. The method of claim 10, wherein the low melting point metal of the low melting point metal powder comprises one or more metals selected from Sn, and combinations thereof_96.5Ag_3.0Cu_0.5、Sn₄₂Bi₅₈And Sn₇₂Bi₂₈At least one of the choices.

14. The method of claim 10, wherein

The conductive resin layer includes metal particles, a first intermetallic compound, and a matrix resin, and

after the plating of the metal material, a second intermetallic compound is formed on a boundary between the conductive resin layer and the plating layer.

15. The method of claim 14, wherein the first intermetallic compound comprises an intermetallic compound between a low melting point metal of the low melting point metal powder and a metal of the metal particles, and

the second intermetallic compound includes an intermetallic compound between a low-melting metal of the low-melting metal powder and a metal included in the plating layer.

16. The method of any of claims 10-14, wherein the step of preparing the body further comprises: applying a paste for an electrode layer on the body to form an electrode layer, the paste including a conductive metal and glass.

17. An electronic assembly, comprising:

a body including a dielectric layer and an internal electrode; and

an external electrode including a conductive resin layer disposed on the body and a plating layer disposed on the conductive resin layer,

wherein the conductive resin layer includes a second intermetallic compound disposed between the conductive resin layer and the plating layer.

18. The electronic assembly of claim 17, wherein the conductive resin layer comprises metal particles, a first intermetallic compound, and a matrix resin, and

the first intermetallic compound includes an intermetallic compound in a solid state between an element of the low melting point metal and an element of the metal particle.

19. The electronic component according to claim 17, wherein the second intermetallic compound includes an intermetallic compound in a solid state between an element of the low melting point metal and the metal included in the plating layer.

20. The electronic component of claim 17, wherein the second intermetallic compound comprises a Ni-Sn intermetallic compound.

Technical Field

The present disclosure relates to an electronic component and a method of manufacturing the same.

Background

Recently, with the trend of miniaturization and high performance of electronic devices, passive components have also been required to be miniaturized and have high reliability.

The electronic components include passive components such as capacitors, inductors, resistors, and the like. Generally, a passive component includes an external electrode to be connected to an external circuit.

As a method of securing high reliability of the passive component, a technique of applying a conductive resin layer to the external electrode has been disclosed. According to this technique, tensile stress generated in a mechanical environment or a thermal environment can be absorbed to prevent the occurrence of cracks caused by the stress. In addition, in the case of the Power Inductor (PI), a conductive resin layer having improved conductivity is coated due to physical characteristics such as DC resistance (Rdc). However, a portion of the plating may be lost by leaching (leach) due to thermal shock from a heat source, such as welding heat.

Therefore, there is a need to develop an electronic component having external electrodes capable of preventing loss of plating and improving reliability and a method of manufacturing the same.

Disclosure of Invention

An aspect of the present disclosure is to provide an electronic component having improved adhesive strength between a conductive resin layer and a plated layer and a method of manufacturing the same.

An aspect of the present disclosure is to provide an electronic component having improved heat resistance of external electrodes and a method of manufacturing the same.

An aspect of the present disclosure is to provide an electronic component having improved reliability and a method of manufacturing the same.

However, the purpose of the present disclosure is not limited to the above description, and will be more readily understood in the course of describing specific embodiments of the present disclosure.

According to an aspect of the present disclosure, an electronic component includes a main body including a dielectric layer and an inner electrode, and an outer electrode including a conductive resin layer disposed on the main body and a plating layer disposed on the conductive resin layer. The conductive resin layer includes metal particles, a first intermetallic compound, and a matrix resin, and the conductive resin layer further includes a second intermetallic compound disposed on a boundary between the conductive resin layer and the plating layer.

According to an aspect of the present disclosure, a method for manufacturing an electronic component includes: preparing a body including a dielectric layer and an inner electrode; applying a paste for a conductive resin layer to the body and drying on the body, and then performing a curing heat treatment to form a conductive resin layer; and plating a metal material on the conductive resin layer, and then performing a plating heat treatment to form a plated layer. The paste for the conductive resin layer includes a metal powder coated with a first organic material, a low melting point metal powder coated with a second organic material, and a matrix resin.

According to an aspect of the present disclosure, an electronic component includes: a body including a dielectric layer and an internal electrode; and an external electrode including a conductive resin layer disposed on the body and a plating layer disposed on the conductive resin layer. Wherein the conductive resin layer includes a second intermetallic compound disposed between the conductive resin layer and the plating layer.

Drawings

The above and other aspects, features and advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

Fig. 1 is a schematic perspective view of an electronic assembly according to an embodiment of the present disclosure.

Fig. 2 is a sectional view taken along line I-I' in fig. 1.

Fig. 3 is an enlarged view of a region B in fig. 2.

Fig. 4 is a schematic exploded perspective view of a main body in which dielectric layers and internal electrodes of fig. 1 are stacked.

Fig. 5 is an image captured by a Scanning Electron Microscope (SEM) showing a section of an external electrode according to an example of the invention.

Fig. 6 is an enlarged view of a boundary portion between the Ni plating layer and the conductive resin layer in fig. 5.

Fig. 7 shows the result of analyzing the "+" part in fig. 6 using an X-ray energy spectrometer (EDS).

Fig. 8 is an image showing a cross section of an outer electrode according to a comparative example captured by a Scanning Electron Microscope (SEM).

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to specific embodiments and drawings. However, embodiments of the present disclosure may be modified to have various other forms, and the scope of the present disclosure is not limited to the embodiments described below. Furthermore, embodiments of the present disclosure may be provided to more fully describe the present disclosure to those of ordinary skill. Therefore, the shapes and sizes of elements in the drawings may be exaggerated for clarity of the description, and elements denoted by the same reference numerals in the drawings may be the same elements.

Values for parameters describing properties such as 1D dimensions of an element (including, but not limited to, "length," "width," "thickness," "diameter," "distance," "gap," and/or "dimension"), 2-D dimensions of an element (including, but not limited to, "area" and/or "dimension"), 3D dimensions of an element (including, but not limited to, "volume" and/or "dimension"), and properties of an element (including, but not limited to, "roughness," "density," "weight ratio," and/or "molar ratio") can be obtained by the methods and/or tools described in this disclosure. However, the present disclosure is not limited thereto. Other methods and/or tools (even if not described in this disclosure) that would be understood by one of ordinary skill in the art may also be used.

In the drawings, portions irrelevant to the description will be omitted for clarity of the present disclosure, and the thickness may be exaggerated to clearly show layers and regions. Furthermore, unless specifically stated otherwise, throughout the description, when an assembly is referred to as "comprising" or "includes" an element, it means that the assembly may also include other elements.

In the drawings, the X direction may be defined as a second direction, an L direction, or a length direction; the Y direction may be defined as a third direction, a W direction, or a width direction; and the Z direction may be defined as a first direction, a stacking direction, a T direction, or a thickness direction.

Electronic assembly

Fig. 1 is a schematic perspective view of an electronic assembly according to an embodiment of the present disclosure.

Fig. 2 is a sectional view taken along line I-I' in fig. 1.

Fig. 3 is an enlarged view of a region B in fig. 2.

Fig. 4 is a schematic exploded perspective view of a main body in which dielectric layers and internal electrodes of fig. 1 are stacked.

Hereinafter, an electronic component 100 according to an embodiment of the present disclosure will be described with reference to fig. 1 to 4. Further, the embodiments of the present invention are described taking a capacitor as an example, but the present disclosure is not limited thereto. Note that the present disclosure is applicable to an electronic component provided with an external electrode including a conductive resin layer and a plated layer.

The electronic assembly 100 according to the embodiment may include: a body 110 including a dielectric layer 111 and internal electrodes 121 and 122; and external electrodes 130 and 140 including conductive resin layers 132 and 142 disposed on the body 110 and plating layers 133 and 143 disposed on the conductive resin layers 132 and 142. The conductive resin layer may include metal particles 132a, a first intermetallic compound 132b, and a matrix resin 132 c. The conductive resin layer may further include a second intermetallic compound 132d, and the second intermetallic compound 132d may be disposed on a boundary between the conductive resin layer and the plating layer.

In the body 110, dielectric layers 111 are alternately stacked with internal electrodes 121 and 122.

Although the specific shape of the body 110 is not necessarily limited, as shown, the body 110 may have a hexahedral shape or the like. The body 110 may not have a perfectly hexahedral shape of a perfect straight line due to shrinkage of ceramic powder particles contained in the body 110 during a sintering process, but may have a substantially hexahedral shape as a whole.

The body 110 may have a first surface 1 and a second surface 2 opposite to each other in a thickness direction (Z direction), a third surface 3 and a fourth surface 4 connected to the first surface 1 and the second surface 2 and opposite to each other in a length direction (X direction), and a fifth surface 5 and a sixth surface 6 connected to the first surface 1 and the second surface 2, connected to the third surface 3 and the fourth surface 4, and opposite to each other in a width direction (Y direction).

The plurality of dielectric layers 111 forming the body 110 may be in a sintered state, and adjacent dielectric layers 111 may be integrated with each other, so that boundaries between them are not easily apparent without using a Scanning Electron Microscope (SEM).

According to the embodiment, the raw material for forming the dielectric layer 111 is not necessarily limited as long as a sufficient capacitance can be obtained therefrom. For example, the raw material may be a barium titanate-based material, a lead composite perovskite-based material, a strontium titanate-based material, or the like. The barium titanate-based material may include BaTiO₃Based ceramic powder particles. An example of the ceramic powder particles may be (Ba)_1-xCa_x)TiO₃、Ba(Ti_1-yCa_y)O₃、(Ba_1-xCa_x)(Ti_1-yZr_y)O₃Or Ba (Ti)_1-yZr_y)O₃Etc., wherein calcium (Ca), zirconium (Zr), etc. are partially dissolved in BaTiO in solid solution₃In (1).

In addition to the ceramic powder particles, various ceramic additives, organic solvents, binders, dispersants, and the like may be added as raw materials for forming the dielectric layer 111 according to the purpose of the present disclosure.

The body 110 may include: a capacitance forming part disposed in the body 110, in which a capacitance is formed, and including a first internal electrode 121 and a second internal electrode 122 disposed to be opposite to each other with the dielectric layer 111 interposed therebetween; and an upper protective layer 112 and a lower protective layer 113 disposed above and below the capacitance forming part, respectively.

The capacitance forming part contributes to the formation of capacitance of the capacitor, and may be formed by repeatedly laminating a plurality of first and second internal electrodes 121 and 122 with respective dielectric layers 111 interposed between the plurality of first and second internal electrodes 121 and 122.

The upper and lower protective layers 112 and 113 may be formed by laminating one or two or more dielectric layers in a vertical direction on the upper and lower surfaces of the capacitor formation part, respectively, and may serve to prevent the first and second internal electrodes 121 and 122 from being damaged by physical or chemical stress.

The upper and lower protective layers 112 and 113 may not include the inner electrode and may include the same material as the dielectric layer 111.

The internal electrodes may include a first internal electrode 121 and a second internal electrode 122. The first and second internal electrodes 121 and 122 are alternately disposed to face each other with the respective dielectric layers 111 constituting the body 110 interposed therebetween, and the first and second internal electrodes 121 and 122 may be exposed to the third and fourth surfaces 3 and 4 of the body 110, respectively.

The first internal electrode 121 may be spaced apart from the fourth surface 4 and may be exposed through the third surface 3, and the second internal electrode 122 may be spaced apart from the third surface 3 and may be exposed through the fourth surface 4.

In this case, the first and second internal electrodes 121 and 122 may be electrically separated from each other by the respective dielectric layers 111 interposed therebetween.

Referring to fig. 4, the body 110 may be formed by alternately stacking ceramic green sheets on which the first internal electrodes 121 are printed and ceramic green sheets on which the second internal electrodes 122 are printed, and then sintering the stacked ceramic green sheets.

The material for forming the internal electrodes 121 and 122 is not necessarily limited, and a material having improved conductivity may be used. For example, the internal electrodes 121 and 122 may be formed by printing a conductive paste for internal electrodes, which includes at least one of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), or an alloy thereof, on a ceramic green sheet.

A screen printing method, a gravure printing method, or the like may be used as a printing method of the conductive paste for the internal electrode, but the present disclosure is not limited thereto.

The outer electrodes 130 and 140 may be disposed on the body 110 and connected to the inner electrodes 121 and 122, respectively. In addition, the external electrode may include first and second external electrodes 130 and 140, and the first and second external electrodes 130 and 140 are disposed on the third and fourth surfaces 3 and 4 of the body 110, respectively, to be connected to the first and second internal electrodes 121 and 122, respectively.

Although the structure in which the electronic component 100 includes the two outer electrodes 130 and 140 has been described in the present embodiment, the number, shape, and the like of the outer electrodes 130 and 140 may be changed according to the shape or other uses of the inner electrodes 121 and 122.

The external electrodes 130 and 140 include conductive resin layers 132 and 142 disposed on the body 110, respectively, and plating layers 133 and 143 disposed on the conductive resin layers 132 and 142, respectively.

Fig. 3 is an enlarged view of the region B in fig. 2.

The region B is illustrated by enlarging a portion of the first external electrode 130, but the first and second external electrodes 130 and 140 are similar to each other in configuration except that the first external electrode 130 is electrically connected to the first internal electrode 121 and the second external electrode 140 is connected to the second internal electrode 122. Therefore, hereinafter, a description will be given based on the first external electrode 130, but the description is considered to be applicable to the description of the second external electrode 140 as well.

The conductive resin layer 132 includes metal particles 132a, a first intermetallic compound 132b, and a matrix resin 132 c. The conductive resin layer 132 may serve to electrically connect the plating layer 133 and the internal electrode 121 to each other, and may absorb tensile stress generated in a mechanical environment or a thermal environment when an electronic component is mounted on a substrate, to prevent crack from occurring and to protect the electronic component from bending impact of the substrate.

The metal particles 132a may include at least one of silver (Ag), copper (Cu), or a mixture thereof, and in more detail, may include Ag.

When the low melting point metal and the metal particles 132a are in a molten state during the drying and solidifying heat treatment to form the conductive resin layer 132, the first intermetallic compound 132b may be disposed to surround the plurality of metal particles 132a and, thus, may serve to connect the plurality of metal particles 132a to each other. In addition, the first intermetallic compound 132b may significantly reduce stress in the body 110, and may improve high-temperature load and humidity resistance characteristics. Here, the curing heat treatment may refer to performing the curing treatment at the curing temperature of the resin, however, the temperature of the curing heat treatment is not limited to the curing temperature of the resin.

In this case, the first intermetallic compound 132b may be a different material from the second intermetallic compound 132 d. The first intermetallic compound 132b may be an intermetallic compound between the low melting point metal and the metal particles 132 a. For example, in the electronic component 100, the first intermetallic compound may include an intermetallic compound in a solid state between an element of the low melting point metal and an element of the metal particle. In addition, the second intermetallic compound may include an intermetallic compound in a solid state between an element of the low melting point metal and the metal included in the plating layer, as an example, but the embodiment is not limited thereto (will be described in detail below).

As will be described later, the conductive resin layer of the present disclosure may be formed by: a paste for a conductive resin layer (including a metal powder coated with a first organic material, a low melting point metal powder coated with a second organic material, and a base resin) is applied to the body 110 and dried, and then a curing heat treatment is performed thereon. The low-melting metal of the low-melting metal powder is partially melted during the drying and solidifying heat treatment, and may form the first intermetallic compound 132b with a portion of the metal particles disposed to surround the metal particles 132 a. For example, the peripheral portion of the metal particle 132a may form the first intermetallic compound 132b with the low melting point metal. In this case, the low-melting metal may have a melting point of 300 ℃ or less.

In some embodiments, the low melting point metal includes any metal having a melting point of 300 ℃ or less. As a more detailed example, the low melting point metal may include Sn, Sn_96.5Ag_3.0Cu_0.5、Sn₄₂Bi₅₈And Sn₇₂Bi₂₈At least one of the choices. In some embodiments, the metal particles 132a include at least one of Cu and Ag. After the paste for the conductive resin layer is applied to the body 110, Sn is melted during drying and curing. The molten Sn included in the low melting point metal wets metal particles having a higher melting point than the low melting point metal due to capillary action and reacts with a portion of the metal particles to form a first intermetallic compound 132b (such as Ag)₃Sn、Cu₆Sn₅、Cu₃Sn, etc.).As shown in fig. 3, Ag or Cu of the metal particles, which is not used for the reaction to form the first intermetallic compound 132b, will remain in the form of the metal particles 132 a. In addition, even when the drying and curing thermal process is completed, a portion of Sn included in the low melting point metal powder, which is not used for reaction to form the first intermetallic compound, may react with the plating layers 133 and 143 during the subsequent plating heat treatment to form the second intermetallic compound. In addition, even after the plating heat treatment, a part of the low melting point metal may be contained in the first intermetallic compound. Here, the plating heat treatment may refer to performing a heat treatment after plating.

The first intermetallic compound 132b and/or the metal particles 132a may serve to electrically connect the internal electrode 121 and the plating layer 133 to each other and reduce Equivalent Series Resistance (ESR).

Referring to fig. 2 and 3, an electrode layer 131 including a conductive metal and glass may be further disposed between the conductive resin layer 132 and the body 110. However, the present disclosure is not limited thereto, and the conductive resin layer 132 may be in direct contact with the body 110 to be directly connected to the internal electrode 121.

The matrix resin 132c may include a thermosetting resin having an electrical insulation property.

In this case, the thermosetting resin may include, for example, an epoxy resin, but the present disclosure is not limited thereto. For example, the thermosetting resin may include a resin having a low molecular weight that remains liquid at room temperature among a bisphenol-a resin, a glycol epoxy resin, a novolac epoxy resin, or derivatives thereof.

The plating layer 133 is disposed on the conductive resin layer 132. In some embodiments, the plating layer 133 may include nickel (Ni).

An additional plating layer 134 may be disposed on the plating layer 133. In addition, the additional plating layer 134 may include at least one of tin (Sn), palladium (Pd), or an alloy thereof, and may include a plurality of layers.

The second intermetallic compound 132d is disposed on the boundary between the conductive resin layer 132 and the plating layer 133.

Generally, after the conductive resin layer 132 is formed, the plating layer 134 is formed by using a metal exposed on the surface of the conductive resin layer as a seed. However, a part of the metal for forming the plating layer may be leached into the conductive resin layer 132 due to thermal shock such as soldering heat.

However, according to the present disclosure, since the second intermetallic compound 132d is formed on the boundary between the conductive resin layer 132 and the plating layer 133, the adhesive strength between the conductive resin layer 132 and the plating layer 133 may be improved, and a portion of the plating layer may be prevented from being lost due to thermal shock such as soldering heat being leached out.

The method of forming the second intermetallic compound 132d is not necessarily limited. As a detailed example, as will be described later, the second intermetallic compound 132d may be formed while forming a plated layer on the conductive resin layer after forming the conductive resin layer using a paste for the conductive resin layer, the paste including a metal powder coated with the first organic material, a low melting point metal powder coated with the second organic material, and a base resin. For example, the low melting point metal of the low melting point metal powder may form the second intermetallic compound 132d during the plating heat treatment for forming the plated layer.

Accordingly, the first intermetallic compound 132b may be an intermetallic compound between the low melting point metal and the metal of the metal particles 132a, and the second intermetallic compound 132d may be an intermetallic compound between the low melting point metal and the metal included in the plating layer.

In some embodiments, when Sn-based metal is used as the low melting point metal and Ni is used as the plating layer, the second intermetallic compound 132d may be a Ni — Sn intermetallic compound, and in more detail, may be Ni₃Sn₄. In addition, the second intermetallic compound 132d may be formed on the boundary between the first intermetallic compound 132c and the plating layer 133. In addition, a part of the organic material coated on the metal powder and the low melting point metal powder may be included in the second intermetallic compound 132d (such as Ni — Sn intermetallic compound).

Method for producing an electronic component

Hereinafter, a method for manufacturing an electronic component according to another aspect of the present disclosure will be described in detail. However, descriptions overlapping with those given in the electronic components will be omitted to avoid the overlapping descriptions. In addition, a method for manufacturing a capacitor will be described as an example to describe an embodiment of the present disclosure. However, the present disclosure is not limited thereto, and it is noted that the method of the present disclosure may be applied to a method for manufacturing an electronic component provided with external electrodes including a conductive resin layer and a plated layer.

A method for manufacturing an electronic assembly according to another aspect of the present disclosure may include: preparing a main body including a dielectric layer and an internal electrode, applying and drying a paste for a conductive resin layer to the main body, and then performing a curing heat treatment to form a conductive resin layer, and plating a metal material on the conductive resin layer, and then performing a plating heat treatment to form a plated layer. The paste for the conductive resin layer includes a metal powder coated with a first organic material, a low melting point metal powder coated with a second organic material, and a base resin.

Preparation of the body

In the method for manufacturing an electronic component according to this embodiment, a material such as barium titanate (BaTiO) will be contained₃) Etc. are coated on a carrier film, and then dried to prepare a plurality of ceramic green sheets.

The slurry may be prepared by mixing ceramic powder, a binder and a solvent and formed into a sheet shape having a thickness of several micrometers (μm) using a doctor blade method.

A conductive paste for internal electrodes, including nickel powder, etc., may be applied to the ceramic green sheets using a screen printing method to form internal electrodes. The printing method of the conductive paste may be a screen printing method, a gravure printing method, or the like, but the present disclosure is not limited thereto.

A plurality of green sheets on which internal electrodes are printed are stacked to prepare a multilayer body. In this case, a plurality of green sheets on which internal electrodes are not printed may be stacked on the upper and lower surfaces of the multilayer body to form a cover (i.e., a protective layer).

The multi-layered body may be sintered to prepare a body including the dielectric layer and the internal electrode. In addition, referring to fig. 3, the body 110 may be formed by alternately stacking ceramic green sheets on which the first internal electrodes 121 are printed and ceramic green sheets on which the second internal electrodes 122 are printed, and then sintering the green sheets.

The preparation of the body may further include applying a paste for an electrode including a conductive metal and glass to the sintered body to form the electrode layers 131 and 141.

Forming a conductive resin layer

A paste for the conductive resin layer may be applied to the body 110 and dried, and then a curing heat treatment may be performed to form the conductive resin layers 132 and 142. When the electrode layers 131 and 141 are formed, a paste for a conductive resin layer may be applied to the electrode layers 131 and 141.

The paste for the conductive resin layer includes a metal powder coated with a first organic material, a low melting point metal powder coated with a second organic material, and a base resin. In this case, the low-melting metal may have a melting point of 300 ℃ or less.

For example, the paste for the conductive resin layer may be prepared by mixing Ag powder as metal powder coated with a first organic material, Sn-based solder powder as low melting point metal powder coated with a second organic material, and a thermosetting resin as a base resin to obtain a mixture, and then dispersing and treating the mixture using a 3-roll mill. The Sn-based solder powder may include Sn, Sn_96.5Ag_3.0Cu_0.5、Sn₄₂Bi₅₈And Sn₇₂Bi₂₈And the average particle diameter of Ag included in the Ag powder may be 0.5 to 3 μm, but the present disclosure is not limited thereto.

The thermosetting resin may include, for example, an epoxy resin, but the present disclosure is not limited thereto. The thermosetting resin may be, for example, a resin having a low molecular weight that remains liquid at room temperature among bisphenol-a resin, ethylene glycol epoxy resin, novolac epoxy resin, or derivatives thereof.

In addition, when the paste for the conductive resin layer includes the metal powder coated with the first organic material, the low melting point metal powder coated with the second organic material, and the base resin, the metal material included in the low melting point metal and the plating layer may form the second intermetallic compound 132d on the boundary between the conductive resin layer 132 and the plating layer 133 during the plating heat treatment.

On the other hand, when the metal powder not coated with the organic material and the low-melting metal powder not coated with the organic material are used, most of the low-melting metal powder may be used to form the metal particles and the first intermetallic compound in the drying and curing process during the formation of the conductive resin layer. Therefore, even when the plating layer is formed on the conductive resin layer, the second intermetallic compound 132d may not be formed on the boundary between the conductive resin layer 132 and the plating layer 133 due to an insufficient amount of the low melting point metal that reacts with the metal material of the plating layer to form the intermetallic compound.

In the present disclosure, since the metal powder coated with the first organic material and the low melting point metal powder coated with the second organic material are used, the first organic material and the second organic material for the coating layer may partially suppress the formation of the intermetallic compound even when subjected to the drying and curing process during the formation of the conductive resin layer. Therefore, a part of the low melting point metal may remain in a state where the low melting point metal does not form the first intermetallic compound 132 b. The remaining portion of the low melting point metal may react with the metal material of the plating layer during the subsequent plating heat treatment to form the second intermetallic compound 132 d. Accordingly, the adhesive strength between the conductive resin layer 132 and the plating layer 133 can be improved, and a portion of the plating layer can be prevented from being lost due to thermal shock such as soldering heat being leached out.

In this case, each of the first organic material and the second organic material may be a fatty acid-based organic material. This is because: in the case of the fatty acid-based organic material, the metal included in the low melting point metal and the nickel (Ni) included in the plating layer may more easily form an intermetallic compound during the plating heat treatment.

As a more detailed example, the fatty acid-based organic material may include stearic acid, oleic acid, or derivatives thereof.

The first organic material and the second organic material may be the same. However, the present disclosure is not limited thereto, and the first organic material and the second organic material may be different from each other.

Forming a plating layer

The plating layers 133 and 143 may be formed by plating a metal material on the conductive resin layers 132 and 142, respectively, and then performing a plating heat treatment.

For example, in the method of forming the plating layer, the Ni plating layers 133 and 143 may be formed by plating Ni by electroplating using a metal exposed to the surfaces of the conductive resin layers 132 and 142 as a seed and performing a plating heat treatment. In this case, the plating heat treatment is not necessarily limited. For example, the plating heat treatment may be performed at a temperature of 120 to 200 degrees celsius in nitrogen (N)₂) Performed in an atmosphere, and performed for about 10 hours to 14 hours.

As described above, the low melting point metal of the conductive resin layer and the metal material of the plating layer may form an intermetallic compound to provide a second intermetallic compound on the boundary between the conductive resin layer 132 and the plating layer 133 and the boundary between the conductive resin layer 142 and the plating layer 143. In this case, the metal material of the plating layer may be Ni, and the second intermetallic compound may be a Ni — Sn intermetallic compound.

In addition, an operation of forming additional plating layers 134 and 144 on the plating layers 133 and 143, respectively, may be further performed. For example, an operation of plating Sn on the plating layers 133 and 143, respectively, to form Sn plating layers may be performed.

Examples of the invention

As an inventive example, the conductive resin layer is formed by the following method: ag powder coated with stearic acid, Sn solder powder coated with stearic acid, and epoxy resin were mixed to obtain a mixture, the mixture dispersed and processed using a 3-roll mill was coated on a main body and dried, and then a curing heat treatment was performed. Then, a Ni plating layer was formed by plating Ni on the conductive resin layer using an electroplating method and performing a plating treatment at a temperature of 160 degrees celsius for 12 hours in a nitrogen atmosphere.

As a comparative example, the conductive resin layer was formed by the following method: ag powder not coated with an organic material, Sn solder powder not coated with an organic material, and epoxy resin were mixed to obtain a mixture, the mixture dispersed and processed using a 3-roll mill was coated on a main body and dried, and then a curing heat treatment was performed. Then, a Ni plating layer was formed by plating Ni on the conductive resin layer using an electroplating method and performing a plating treatment at a temperature of 160 degrees celsius for 12 hours in a nitrogen atmosphere.

The inventive examples and the comparative examples were subjected to a solder heat resistance test and a drop test, and the test results are shown in tables 1 and 2, respectively.

In the solder heat resistance test, 100 samples each of the inventive example and the comparative example were prepared and treated at a temperature of 85 degrees celsius and a relative humidity of 85% for 6 hours, and then deposited in a solder bath at 280 degrees celsius for 10 seconds. These processes were performed as many times as the number of repetitions listed in table 1, and the number of samples in which the plating was lost is listed in table 1. In this case, a case in which 10% or more of the plating layer is lost is determined as a loss sample.

In the drop test, 100 samples each of the inventive example and the comparative example were prepared and dropped at a height of 1 meter from the ground, and then, the number of samples in which the plating layer and the conductive resin layer were separated from each other was listed in table 2.

In addition, in each of the invention examples and the comparative examples, a cross section of the body cut at the central portion in the width direction taken along the length and thickness (L-T) direction was analyzed using a Scanning Electron Microscope (SEM) and an X-ray energy spectrometer (EDS) to confirm the presence or absence of a nickel-tin (Ni-Sn) intermetallic compound on the boundary between the conductive resin layer and the Ni plating layer.

TABLE 1

TABLE 2

As can be seen from tables 1 and 2, in the invention examples, the solder heat resistance was excellent and the adhesive strength between the conductive resin layer and the Ni plating layer was excellent.

In addition, in the comparative example, when the solder heat resistance test was repeated nine times, the plating layers of four samples out of 100 samples were lost, thereby deteriorating the solder heat resistance. In addition, when the number of repetitions of the drop test reached 50 times, the plating layer and the conductive resin layer were separated from each other in 5 out of 100 samples, thereby deteriorating the adhesive strength.

In the sample sheet of the invention example in which the solder heat resistance test was repeatedly performed 12 times, when the ESR changes before and after the solder heat resistance test were measured, it was confirmed that the ESR increase rate was 6.54% at maximum, and the ESR increase rate was low.

On the other hand, in the sample piece of the comparative example in which the solder heat resistance test was repeatedly performed 9 times, when the ESR changes before and after the solder heat resistance test were measured, it was confirmed that the ESR increase rate was 123% at maximum, and the ESR increase rate was very high.

In each of the invention examples and the comparative examples, a cross section cut along the length and thickness (L-T) direction of the central portion of the body in the width direction was analyzed using a Scanning Electron Microscope (SEM) and an X-ray energy spectrometer (EDS) to confirm the presence or absence of a nickel-tin (Ni-Sn) intermetallic compound on the boundary between the conductive resin layer and the Ni plating layer.

Fig. 5 is an image captured by a Scanning Electron Microscope (SEM) showing a section of an external electrode according to an example of the invention. Fig. 6 is an enlarged view of a boundary portion between the Ni plating layer and the conductive resin layer in fig. 5. Fig. 7 shows the result of analyzing the "+" part in fig. 6 using an X-ray energy spectrometer (EDS).

As a result of analyzing the graph of fig. 7, the "+" section includes: 2.7 wt% of carbon (C), 4.59 wt% of oxygen (O), 27.27 wt% of nickel (Ni) and 65.44 wt% of tin (Sn) by mass ratio, and including: by atomic weight ratio, 14.74 at% of C, 18.77 at% of O, 30.40 at% of Ni and 36.09 at% of Sn. Thus, the second gold disposed on the boundary between the conductive resin layer 132 and the Ni plating layer 133 was confirmedThe intergeneric compound 132d is Ni₃Sn₄(Ni-Sn intermetallic compound).

Fig. 8 is an image showing a cross section of an outer electrode according to a comparative example captured by a Scanning Electron Microscope (SEM). As can be seen from fig. 8, the second intermetallic compound was not observed.

Therefore, it was confirmed that when the second intermetallic compound 132d is formed on the boundary between the conductive resin layer 132 and the plating layer 133 according to the present disclosure, the adhesive strength between the conductive resin layer 132 and the plating layer 133 may be improved, and a portion of the plating layer may be prevented from being lost due to thermal shock such as soldering heat being leached out.

As described above, according to the present disclosure, the first intermetallic compound may be included in the conductive resin layer to improve high-temperature load and moisture resistance characteristics.

In addition, a second intermetallic compound may be disposed on a boundary between the conductive resin layer and the plating layer to improve adhesive strength between the conductive resin layer and the plating layer.

While embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the scope of the disclosure as defined by the appended claims.