Electronic components and methods for manufacturing electronic components

Abstract

To provide an electronic component that suppresses deterioration in electrical characteristics.SOLUTION: An electronic component includes: an element body 3 having an end surface 3a; an external electrode 5 arranged on the end surface 3a; and an internal electrode 7 arranged in the element body 3. The internal electrode 7 is joined to the external electrode 5. A bonding interface 13 between the external electrode 5 and the internal electrode 7 is located on an inner side of the element body 3 with respect to the end surface 3a. The internal electrode 7 contains a first metal. The external electrode 5 contains a second metal different from the first metal. A mutual diffusion region R including the first metal and the second metal is present in each of the external electrode 5 and the internal electrode 7 across the bonding interface 13.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an electronic component and a method for manufacturing the same.

Background Art

[0002] A known electronic component includes a body having an end face, an external electrode disposed on the end face, and an internal electrode disposed inside the body (for example, Patent Document 1). The internal electrode is joined to the external electrode. The internal electrode is exposed from the end face. The joining interface between the external electrode and the internal electrode is located on the end face of the body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] One end of the internal electrode may protrude outside the body. The external electrode has, for example, a sintered metal layer and a plating layer. The plating layer is formed by performing a plating process on the sintered metal layer. In a configuration where one end of the internal electrode protrudes outside the body, the joining interface between the external electrode and the internal electrode is located outside the body from the end face. In this case, when performing the above-described plating process, the plating solution may enter the inside of the body from between one end of the internal electrode and the body. When the plating solution enters the inside of the body, the electrical characteristics of the electronic component may deteriorate.

[0005] One aspect of the present invention aims to provide an electronic component that suppresses deterioration of electrical characteristics. Another aspect of the present invention aims to provide a method for manufacturing an electronic component that suppresses deterioration of electrical characteristics.

Means for Solving the Problems

[0006] An electronic component according to one embodiment comprises a body having an end face, an external electrode disposed on the end face, and an internal electrode disposed within the body. The internal electrode is joined to the external electrode. The interface between the external electrode and the internal electrode is located inside the body beyond the end face. The internal electrode contains a first metal. The external electrode contains a second metal different from the first metal. Interdiffusion regions containing the first metal and the second metal exist on both the external electrode and the internal electrode, respectively, with the interface between them.

[0007] In the above embodiment, the bonding interface between the external electrode and the internal electrode is located inside the substrate beyond the end face. Interdiffusion regions exist on both the external and internal electrodes, separated by the bonding interface. Since the interdiffusion regions contain both the primary metal contained in the internal electrode and the secondary metal contained in the external electrode, they have a higher density than regions other than the interdiffusion regions. Therefore, even when performing plating, the plating solution has difficulty penetrating into the substrate. As a result, the above embodiment suppresses the deterioration of electrical properties.

[0008] A method for manufacturing an electronic component according to another embodiment includes the steps of: preparing a body in which an internal electrode containing a first metal is disposed inside; forming a recess in the body at the bottom, in which one end of the internal electrode is exposed, by irradiating the body with laser light; and arranging an external electrode containing a second metal different from the first metal on the surface where the recess opens. The arranging step includes joining the external electrode and the internal electrode such that interdiffusion regions containing the first metal and the second metal exist on both the external electrode and the internal electrode, with the junction interface between the external electrode and the internal electrode in between.

[0009] In one of the other embodiments described above, a recess is formed at the bottom of the substrate by irradiating it with laser light, exposing one end of the internal electrode. The external electrode and the internal electrode are joined such that mutual diffusion regions exist on both the external electrode and the internal electrode, with the joining interface in between. As a result, this other embodiment reliably provides an electronic component that suppresses the degradation of electrical characteristics. [Effects of the Invention]

[0010] One aspect of the present invention provides an electronic component that suppresses the degradation of electrical characteristics. Another aspect of the present invention provides a method for manufacturing an electronic component that suppresses the degradation of electrical characteristics. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a perspective view showing an electronic component according to one embodiment. [Figure 2] Figure 2 shows the cross-sectional configuration of the electronic component according to this embodiment. [Figure 3] Figure 3 shows the internal electrodes and recesses. [Figure 4] Figure 4 shows the configuration of the external electrode, internal electrode, and recess. [Figure 5] Figure 5 is a flowchart showing the method for manufacturing electronic components according to this embodiment. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described in detail below with reference to the attached drawings. In this description, the same reference numerals will be used for elements that are the same or have the same function, and redundant explanations will be omitted.

[0013] The configuration of the electronic component according to this embodiment will be described with reference to Figures 1 to 4. Figure 1 is a perspective view showing the electronic component according to this embodiment. Figure 2 is a diagram showing the cross-sectional configuration of the electronic component according to this embodiment. Figure 3 is a diagram showing the internal electrode and recess. Figure 4 is a diagram showing the configuration of the external electrode, internal electrode and recess.

[0014] As shown in Figures 1 and 2, the electronic component 1 comprises a base body 3, an external electrode 5, a plurality of internal electrodes 7, and a plurality of internal electrodes 9. In this embodiment, the electronic component 1 comprises a pair of external electrodes 5. In this embodiment, the electronic component 1 is a multilayer ceramic capacitor.

[0015] The base body 3 has a rectangular parallelepiped shape. The rectangular parallelepiped shape includes, for example, a rectangular parallelepiped shape with chamfered corners and edges, and a rectangular parallelepiped shape with rounded corners and edges. The base body 3 has a pair of end faces 3a, a pair of side faces 3c, and a pair of side faces 3e. In this embodiment, the pair of end faces 3a face each other in a first direction D1, the pair of side faces 3c face each other in a second direction D2, and the pair of side faces 3e face each other in a third direction D3. The pair of end faces 3a, the pair of side faces 3c, and the pair of side faces 3e constitute the outer surface of the base body 3. The pair of side faces 3c and the pair of side faces 3e are each adjacent to the pair of end faces 3a and extend in the first direction D1 to connect the pair of end faces 3a.

[0016] The first direction D1 is the length direction of the base body 3, the second direction D2 is the width direction of the base body 3, and the third direction D3 is the height direction of the base body 3. The length of the base body 3 is between 0.4 mm and 7.5 mm. The width of the base body 3 is between 0.2 mm and 6.3 mm. The height of the base body 3 is between 0.2 mm and 2.8 mm. In this embodiment, the length of the base body 3 is 5.7 mm, the width of the base body 3 is 5.0 mm, and the height of the base body 3 is 2.6 mm.

[0017] The element 3 is composed of multiple dielectric layers stacked on top of each other. Each dielectric layer is stacked in a third direction D3. The element 3 contains multiple stacked dielectric layers. Each dielectric layer is composed of, for example, a sintered body of a ceramic green sheet containing a dielectric material. The dielectric material is, for example, a dielectric ceramic of the BaTiO3 system, Ba(Ti,Zr)O3 system, (Ba,Ca)TiO3 system, CaZrO3 system, or (Ca,Sr)ZrO3 system. Each dielectric layer is integrated to such an extent that the boundaries between each dielectric layer are not visible.

[0018] As shown in FIG. 2, the internal electrode 7 and the internal electrode 9 are arranged at different positions in the third direction D3. The internal electrode 7 and the internal electrode 9 are alternately arranged so as to face each other with a gap in the third direction D3 within the base body 3. The plurality of internal electrodes 7, 9 face each other in the third direction D3. The internal electrode 7 and the internal electrode 9 have different polarities from each other. The internal electrode 7 has one end 7a exposed from one of the pair of end faces 3a. The internal electrode 9 has one end 9a exposed from the other of the pair of end faces 3a. One end 7a of the internal electrode 7 is exposed from one of the pair of end faces 3a. One end 9a of the internal electrode 9 is exposed from the other of the pair of end faces 3a. The internal electrodes 7, 9 contain a conductive material. The conductive material contains a metal M1. The internal electrodes 7, 9 contain the metal M1. The metal M1 contains, for example, Cu, Ni, or Pt. In the present embodiment, the metal M1 contained in the internal electrodes 7, 9 is Ni. The internal electrodes 7, 9 are configured, for example, as a sintered body of a conductive paste containing the above conductive material.

[0019] As shown in FIGS. 1 and 2, the pair of external electrodes 5 are arranged on the base body 3. The pair of external electrodes 5 are spaced apart from each other in the first direction D1. The pair of external electrodes 5 are arranged on the surface of the base body 3. The external electrode 5 is arranged on the end face 3a. In the present embodiment, the external electrode 5 is also arranged on a part of each of the pair of side faces 3c and the pair of side faces 3e. The portion of the external electrode 5 arranged on the end face 3a is arranged so as to cover the one ends 7a, 9a exposed from the end face 3a of the corresponding internal electrodes 7, 9. The portion of the external electrode 5 arranged on the end face 3a is joined to the one ends 7a, 9a of the corresponding internal electrodes 7, 9. Thereby, the external electrode 5 is joined to the corresponding internal electrodes 7, 9. The external electrode 5 is electrically connected to the corresponding internal electrodes 7, 9.

[0020] As shown in FIG. 2, the external electrode 5 has an electrode layer E1 and an electrode layer E2. The electrode layer E1 is formed on the base body 3. The electrode layer E2 is formed on the electrode layer E1. In the present embodiment, each portion of the external electrode 5 disposed on one end face 3a, a pair of side faces 3c, and a pair of side faces 3e has the electrode layer E1 and the electrode layer E2. The electrode layer E2 constitutes the outermost layer of the external electrode 5.

[0021] The electrode layer E1 is formed by drying and baking a conductive paste applied to the surface of the base body 3. The electrode layer E1 is a sintered metal layer formed on the base body 3. The conductive paste contains, for example, a metal M2 different from the metal M1 contained in the internal electrodes 7 and 9, glass, resin, and an organic solvent. The external electrode 5 contains a metal M2 different from the metal M1 contained in the internal electrodes 7 and 9. The metal M2 contains Cu, Ni, or Ag - Pd. In the present embodiment, the metal M2 contained in the external electrode 5 is Cu, and the electrode layer E1 is a sintered metal layer made of Cu. For example, when the metal M1 is the first metal, the metal M2 is the second metal.

[0022] The electrode layer E2 is a plating layer formed on the electrode layer E1. The electrode layer E2 is formed on the electrode layer E1 by, for example, a plating method. In the present embodiment, the electrode layer E2 is formed so as to cover the entire electrode layer E1. The electrode layer E1 is a base layer for forming the electrode layer E2. The electrode layer E1 is a base metal layer. The electrode layer E2 may be a Ni plating layer formed by Ni plating on the electrode layer E1. The electrode layer E2 may contain, for example, a Ni plating layer formed on the electrode layer E1 and a Sn plating layer formed on the Ni plating layer.

[0023] The base body 3 has depressions 11 formed therein. In the present embodiment, a plurality of depressions 11 are formed in the base body 3. In the present embodiment, the number of depressions 11 corresponding to the number of the internal electrodes 7 and 9 exposed from the end face 3a is formed. The depression 11 opens to the end face 3a. The depression 11 is recessed in the direction from the end face 3a toward the inside of the base body 3 in the first direction D1. In the present embodiment, the depression 11 is formed so as to extend in the second direction D2.

[0024] As shown in Figure 3, the recess 11 is formed in a position that overlaps with the internal electrode 7 when viewed from the first direction D1. The recess 11 is formed in the same position as the internal electrode 7 when viewed from the third direction D3. In this embodiment, the recess 11 is formed to surround the entire circumference of the internal electrode 7 when viewed from the first direction D1. One end 7a of the internal electrode 7 is completely surrounded by the recess 11 when viewed from the first direction D1. Although not shown in the diagram, the recess 11 is formed in a position that overlaps with the internal electrode 9 when viewed from the first direction D1. The recess 11 is formed in the same position as the internal electrode 9 when viewed from the third direction D3. In this embodiment, the recess 11 is formed so as to surround the entire circumference of the internal electrode 9 when viewed from the first direction D1. One end 9a of the internal electrode 9 is completely surrounded by the recess 11 when viewed from the first direction D1.

[0025] The recess 11 is defined by the bonding interface 13 between the external electrode 5 and the internal electrodes 7,9 and the inner wall surface 11a. The bonding interface 13 defines the bottom of the recess 11. The inner wall surface 11a consists of four surfaces: a pair of surfaces 11a1 and a pair of surfaces 11a2. The pair of surfaces 11a1 face each other in the third direction D3. The pair of surfaces 11a2 face each other in the second direction D2. As shown in Figure 4, the pair of surfaces 11a1 are inclined such that the distance between them increases as they move toward the opening of the recess 11. The distance between the pair of surfaces 11a1 is minimum at the bottom of the recess 11 and maximum at the opening of the recess 11. In this embodiment, the pair of surfaces 11a2 are also inclined such that the distance between them increases as they move toward the opening of the recess 11. The region defined by the inner wall surface 11a has a frustoconical shape.

[0026] The recess 11 has a depth d. The depth d is defined by the length in the first direction D1 from the bonding interface 13 between the external electrode 5 and the internal electrodes 7,9 to the reference plane P including the end face 3a. The depth d is, for example, 0.5 μm or more and 10 μm or less. In this embodiment, the depth d is 3 μm. The recess 11 has a width w. The width w is defined by the length of the recess 11 in the third direction D3. The width w is the maximum width of the recess 11 in the third direction D3. The width w is, for example, 1 μm or more and 10 μm or less. In this embodiment, the width w is 5 μm.

[0027] As shown in Figures 3 and 4, the internal electrode 7 is exposed at the bottom of the recess 11. One end 7a of the internal electrode 7 is exposed at the bottom of the recess 11. Because one end 7a is exposed at the bottom of the recess 11, the internal electrode 7 is exposed from one of the pair of end faces 3a. In this embodiment, the entire end 7a is exposed at the bottom of the recess 11 from one of the pair of end faces 3a. Each internal electrode 7 is joined to the corresponding external electrode 5 at one end 7a. The joining interface 13 between the external electrode 5 and the internal electrode 7 is located inside the body 3 beyond one of the end faces 3a. Although not shown in the diagram, the internal electrode 9 is exposed at the bottom of the recess 11. One end 9a of the internal electrode 9 is exposed at the bottom of the recess 11. Because one end 9a is exposed at the bottom of the recess 11, the internal electrode 9 is exposed from the other end face 3a of the pair of end faces 3a. In this embodiment, the entire one end 9a is exposed at the bottom of the recess 11 from the other end face 3a of the pair of end faces 3a. Each internal electrode 9 is joined to the corresponding external electrode 5 at one end 9a. The joining interface 13 between the external electrode 5 and the internal electrode 9 is located inside the body 3 beyond the other end face 3a.

[0028] The thickness of the electrode layer E1 differs between the positions where the depressions 11 are formed and the positions where the depressions 11 are not formed. The thickness of the electrode layer E1 at the positions where the depressions 11 are formed is greater than the thickness of the electrode layer E1 at the positions where the depressions 11 are not formed. The thickness of the external electrode 5 at the positions where the depressions 11 are formed is greater than the thickness of the external electrode 5 at the positions where the depressions 11 are not formed. The thickness of the electrode layer E1 and the thickness of the external electrode 5 are determined by the length of the electrode layer E1 in the first direction D1 and the length of the external electrode 5 in the first direction D1, respectively.

[0029] As shown in Figure 4, the interdiffusion region R exists in both the external electrode 5 and the internal electrode 7. The interdiffusion region R exists in both the external electrode 5 and the internal electrode 7, separated by the bonding interface 13 between the external electrode 5 and the internal electrode 7. The interdiffusion region R exists in the electrode layer E1 of the external electrode 5 that is bonded to the internal electrode 7. The internal electrode 7 and the external electrode 5 that is bonded to the internal electrode 7 have the interdiffusion region R. The interdiffusion region R is located within the recess 11. Of the interdiffusion region R, the portion that exists in the external electrode 5 that is bonded to the internal electrode 7 is located within the recess 11. Although not shown in the diagram, the interdiffusion region R exists in both the external electrode 5 and the internal electrode 9. The interdiffusion region R exists in both the external electrode 5 and the internal electrode 9, separated by the bonding interface 13 between the external electrode 5 and the internal electrode 9. The interdiffusion region R exists in the electrode layer E1 of the external electrode 5 that is bonded to the internal electrode 9. The internal electrode 9 and the external electrode 5 that is bonded to the internal electrode 9 have the interdiffusion region R. The interdiffusion region R is located within the recess 11. Of the interdiffusion region R, the portion that exists in the external electrode 5 that is bonded to the internal electrode 9 is located within the recess 11.

[0030] The interdiffusion region R includes metal M1 contained in the internal electrodes 7 and 9 and metal M2 contained in the external electrode 5. The interdiffusion region R is a region where metal M1 and metal M2 are diffusing with each other. The interdiffusion region R contains an alloy containing 50 atomic percent each of metal M1 and metal M2. In this embodiment, the interdiffusion region R contains 50 atomic percent each of metal M1 and metal M2 at the bonding interface 13. At the bonding interface 13, an alloy of metal M1 and metal M2 is formed at 50 atomic percent each. In this embodiment, as described above, metal M1 is Ni and metal M2 is Cu. Therefore, in this embodiment, the interdiffusion region R contains 50 atomic percent each of Ni and Cu at the bonding interface 13.

[0031] As explained above, in electronic component 1, the bonding interface 13 between the external electrode 5 and the internal electrodes 7 and 9 is located inside the base body 3 from the end face 3a. The interdiffusion region R exists on both the external electrode 5 and the internal electrodes 7 and 9, with the bonding interface 13 in between. Since the interdiffusion region R contains the metal M1 contained in the internal electrodes 7 and 9 and the metal M2 contained in the external electrode 5, it has a higher density compared to the regions other than the interdiffusion region R. Therefore, even when performing plating, the plating solution has difficulty penetrating into the base body 3. As a result, the electronic component 1 suppresses deterioration of its electrical properties.

[0032] When an electronic component in which the plating solution has penetrated the substrate is soldered, for example, the plating solution may gasify. In this case, the gas generated from the plating solution may be ejected outside the substrate. This gas ejection can cause solder cracking. Solder cracking can lead to mounting defects of electronic components. As described above, in electronic component 1, the plating solution has difficulty penetrating into the base body 3. As a result, electronic component 1 suppresses the occurrence of mounting defects.

[0033] In the electronic component 1, the base body 3 has a recess 11 formed therein, which has an interdiffusion region R located inside it, opens to the end face 3a, and has a bonding interface 13 that defines its bottom. In electronic component 1, a configuration in which the bonding interface 13 is located inside the base body 3 beyond the end face 3a can be reliably achieved. As a result, electronic component 1 reliably suppresses the degradation of its electrical characteristics.

[0034] In the electronic component 1, the inner wall surface 11a of the recess 11 includes a pair of surfaces 11a1 that face each other and are inclined such that the distance between them increases as they move toward the opening of the recess 11. In electronic component 1, the amount of conductive paste used to form the electrode layer E1 is reduced compared to an electronic component in which the inner wall surface 11a includes a pair of surfaces extending along the first direction D1. As a result, the external electrode 5 can be easily formed in electronic component 1.

[0035] In electronic component 1, the interdiffusion region R at the bonding interface 13 contains an alloy containing 50 atomic percent of metal M1 and metal M2, respectively. In electronic component 1, even during the plating process, the plating solution is less likely to penetrate the interior of the base body 3. As a result, electronic component 1 more reliably suppresses the deterioration of its electrical properties.

[0036] Next, the method for manufacturing the electronic component 1 in this embodiment will be described with reference to Figure 5. Figure 5 is a flowchart showing the method for manufacturing the electronic component in this embodiment.

[0037] In step S1, a base body 3 is prepared, in which multiple internal electrodes 7 and 9 are arranged inside. The light absorption coefficients of the multiple internal electrodes 7 and 9 are greater than the light absorption coefficient of the base body 3 prepared in step S1. The base body 3 may be newly created in step S1, or an already created base body 3 may be prepared. In the base body 3 prepared in step S1, no recess 11 is formed in the base body 3. In the base body 3 prepared in step S1, one end 7a and 9a of the multiple internal electrodes 7 and 9 are located inside the base body 3 from the end face 3a in the first direction D1.

[0038] In step S2, a recess 11 is formed in the base body 3 by irradiating the end face 3a with laser light. In this manufacturing method, by irradiating the entire end face 3a with laser light, a recess 11 is formed in the base body 3 in which one end 7a, 9a of the internal electrodes 7, 9 is exposed at the bottom. In step S2, by forming multiple recesses 11 in the base body 3, each of the multiple internal electrodes 7, 9 is exposed from the end face 3a at the bottom of each recess 11. That is, by irradiating the entire end face 3a with laser light, each of the multiple internal electrodes 7, 9 is exposed from the end face 3a at the bottom of the recess 11.

[0039] The laser that irradiates the end face 3a is, for example, a rare-earth fiber laser. For example, the laser is a mode-locked pulsed laser, and the laser light is pulsed laser light. The wavelength of the laser light irradiated onto the end face 3a is, for example, 250 nm to 1600 nm. In this embodiment, the wavelength of the laser light irradiated onto the end face 3a is 1060 nm. The pulse time of the laser light irradiated onto the end face 3a is, for example, 10 ps or less. The pulse energy of the laser light irradiated onto the end face 3a is, for example, 5 μJ to 200 μJ.

[0040] In this manufacturing method, a recess 11 is formed in the base body 3 by irradiating the end face 3a with laser light. As described above, in this manufacturing method, the light absorption coefficients of the multiple internal electrodes 7 and 9 are greater than those of the base body 3. Therefore, when viewed from the first direction D1, the recess 11 is formed at the position where the end face 3a and the internal electrodes 7 and 9 overlap. As a result, in the electronic component obtained by this manufacturing method, a recess 11 is formed in the base body 3 at the bottom, exposing one end 7a and 9a of the internal electrodes 7 and 9.

[0041] In step S3, the external electrode 5 is placed on the end face 3a. In this manufacturing method, the external electrode 5 is placed on the surface where the recess 11 opens. The external electrode 5 is placed on the surface where the recess 11 opens through the process shown below. First, an electrode layer E1 is formed on the base body 3. In this process, the conductive paste described above is applied to the entire surface of the end face 3a where the recess 11 opens, and to the ends of the pair of side surfaces 3c and the pair of side surfaces 3e near the end face 3a. Next, the applied conductive paste is baked onto the base body 3 by heat treatment. This forms the electrode layer E1 on the entire surface of the end face 3a where the recess 11 opens, and to the ends of the pair of side surfaces 3c and the pair of side surfaces 3e near the end face 3a. The electrode layer E1 and the internal electrodes 7 and 9 are joined by the baking process described above. In other words, the external electrode 5 and the internal electrodes 7 and 9 are joined in this process. In this manufacturing method, the external electrode 5 and the internal electrodes 7 and 9 are joined such that interdiffusion regions R exist on both the external electrode 5 and the internal electrodes 7 and 9, respectively, with the joining interface 13 in between. The conductive paste is applied, for example, by a dipping method, a printing method, or a transfer method. The electrode layer E1 may be formed, for example, by physical vapor deposition (PVD) or chemical vapor deposition (CVD). Next, an electrode layer E2 is formed on the substrate 3 on which the electrode layer E1 is formed. In this manufacturing method, the electrode layer E2 is formed by a plating method as described above. The electrode layer E2 is formed on the electrode layer E1. The plating method for forming the electrode layer E2 is, for example, electroplating.

[0042] Through the above process, electronic component 1 is obtained. As described above, electronic component 1 suppresses the degradation of its electrical characteristics. The above manufacturing method reliably produces electronic component 1 that suppresses the degradation of its electrical characteristics.

[0043] While embodiments of the present invention have been described above, the present invention is not necessarily limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0044] In the case of electronic component 1, the base body 3 does not necessarily need to have a recess 11 formed therein. As described above, the electronic component 1, in which a recess 11 is formed in the base body 3, reliably suppresses the deterioration of its electrical characteristics.

[0045] In electronic component 1, the pair of surfaces 11a1 do not necessarily have to be inclined such that the distance between them increases as they move toward the opening of the recess 11. In an electronic component 1 in which a pair of surfaces 11a1 are inclined such that the distance between them increases as they move toward the opening of the recess 11, the external electrodes 5 can be easily formed as described above.

[0046] The interdiffusion region R does not necessarily have to contain an alloy at the bonding interface 13 that contains 50 atomic percent of metal M1 and metal M2, respectively. As described above, an electronic component 1 containing an alloy in which the interdiffusion region R at the bonding interface 13 contains 50 atomic percent of metal M1 and metal M2, respectively, more reliably suppresses the degradation of electrical properties.

[0047] In this embodiment, electronic component 1 is described as a multilayer ceramic capacitor, but the electronic components to which the present invention can be applied are not limited to multilayer ceramic capacitors. Applicable electronic components include, for example, multilayer varistors, multilayer piezoelectric actuators, multilayer thermistors, and multilayer solid-state batteries.

[0048] As can be seen from the descriptions of the embodiments described above, this specification includes disclosures of the following embodiments. (Note 1) A base body having an end face, The external electrode arranged on the end face, The body comprises an internal electrode that is located within the body and is connected to the external electrode, The bonding interface between the external electrode and the internal electrode is located inside the body from the end face. The internal electrode contains a first metal, The external electrode includes a second metal different from the first metal, An electronic component in which interdiffusion regions including the first metal and the second metal exist on the external electrode and the internal electrode, respectively, with the bonding interface in between. (Note 2) The electronic component as described in Appendix 1, wherein the substrate has the interdiffusion region located on its inner side, and a recess is formed which opens to the end face and defines the bottom of the bonding interface. (Note 3) The electronic component according to Appendix 2, wherein the inner wall surface of the recess includes a pair of surfaces that face each other and are inclined such that the distance between them increases toward the opening of the recess. (Note 4) The width of the recess is 1 μm or more and 10 μm or less, as specified in any one of the appendices 2 to 3. (Note 5) The depth of the recess is 0.5 μm or more and 10 μm or less, as specified in any one of the appendices 2 to 4. (Note 6) The electronic component described in any one of the appendices 1 to 5, wherein the interdiffusion region includes an alloy containing 50 atomic percent of the first metal and the second metal at the bonding interface. (Note 7) A process for preparing a substrate in which an internal electrode containing a first metal is arranged inside, The process involves irradiating the substrate with laser light to form a recess in the substrate at the bottom, in which the end of the internal electrode is exposed. The process includes arranging an external electrode containing a second metal different from the first metal on the surface where the recess opens, The aforementioned arrangement step is, A method for manufacturing an electronic component, comprising the step of joining an external electrode and an internal electrode such that interdiffusion regions including the first metal and the second metal exist on both the external electrode and the internal electrode, with the joining interface between the external electrode and the internal electrode in between. [Explanation of symbols]

[0049] 1...electronic component, 3...base body, 3a...end face, 5...external electrode, 7,9...internal electrode, 7a,9a...one end, 11...recess, 11a...inner wall surface, 11a1...pair of surfaces, 13...bonding interface, d...depth of recess, M1,M2...metal, R...mutual diffusion region, w...width of recess.

Claims

1. A body having an end face, a pair of sides facing each other and adjacent to the end face, and another pair of sides facing each other and adjacent to the end face and the pair of sides, The external electrode arranged on the end face, The body comprises an internal electrode that is located within the body and is connected to the external electrode, The bonding interface between the external electrode and the internal electrode is located inside the body from the end face. The internal electrode contains a first metal, The external electrode includes a second metal different from the first metal, Interdiffusion regions including the first metal and the second metal exist on the external electrode and the internal electrode, respectively, with the bonding interface in between. The substrate has a recess formed therein, the interdiffusion region located on its inner side, opening to the end face, and the bonding interface defining its bottom, such that the recess extends in a direction in which the pair of sides face each other. An electronic component wherein the recess surrounds the entire circumference of one end of the internal electrode when viewed from a direction perpendicular to the end face, and both ends of the recess in the direction in which the pair of sides face each other are separated from the pair of sides.

2. The electronic component according to claim 1, wherein the inner wall surface of the recess includes a pair of surfaces that face each other and are inclined such that the distance between them increases toward the opening of the recess.

3. The electronic component according to claim 1 or 2, wherein the interdiffusion region includes an alloy containing 50 atomic percent of the first metal and the second metal, respectively, at the bonding interface.

4. The electronic component according to claim 1 or 2, wherein the width of the recess is 1 μm or more and 10 μm or less.

5. The electronic component according to claim 1 or 2, wherein the depth of the recess is 0.5 μm or more and 10 μm or less.

6. A step of preparing a body having an internal electrode containing a first metal disposed inside, having an end face, a pair of sides facing each other and adjacent to the end face, and another pair of sides facing each other and adjacent to the end face and the pair of sides, The process involves irradiating the substrate with laser light to form a recess in the substrate at the bottom, in which one end of the internal electrode is exposed. The process includes arranging an external electrode containing a second metal different from the first metal on the surface where the recess opens, The step of forming the aforementioned recess in the base body is: The process includes forming the recess such that, when viewed from a direction perpendicular to the end face, the recess surrounds the entire circumference of one end of the internal electrode, and both ends of the recess in the direction in which the pair of sides face each other are separated from the pair of sides, The aforementioned arrangement step is, A method for manufacturing an electronic component, comprising the step of joining an external electrode and an internal electrode such that interdiffusion regions including the first metal and the second metal exist on both the external electrode and the internal electrode, with the joining interface between the external electrode and the internal electrode in between.

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