Multilayer ceramic electronic component and manufacturing method therefor

Abstract

This multilayer ceramic electronic component comprises: an element body in which a plurality of internal electrodes and a plurality of dielectric layers mainly composed of ceramic are alternately laminated in a first direction, and the laminated plurality of internal electrodes have end surfaces that are alternately exposed and opposed to each other in a second direction; a base metal layer that is in contact with some of the plurality of internal electrodes exposed from the end surfaces and is disposed at the end portion on the end surface side among surfaces connected to the end surfaces of the element body; a glass layer disposed across from between the tip of the base metal layer and the element body at the end portion to the opposite side of the end surfaces; and a plating layer that is disposed so as to sandwich the base metal layer and the glass layer with the element body at the end portion and forms an external electrode together with the base metal layer.　

Description

Multilayer ceramic electronic component and its manufacturing method

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

[0002] In the case of external electrodes in multilayer ceramic electronic components such as multilayer ceramic capacitors, it is known to form an organic layer on the tip of a base metal layer, and to provide the tip of a plating layer covering the base metal layer on the organic layer (for example, Patent Document 1).

[0003] JP 2018-49881 A

[0004] In the process of forming a plating layer, components of the plating solution may penetrate through the interface between the base metal layer and the element body, which may corrode the internal electrodes.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to suppress deterioration of internal electrodes.

[0006] The present invention is a multilayer ceramic electronic component comprising: an element body in which a plurality of internal electrodes and a plurality of dielectric layers primarily composed of ceramic are alternately stacked in a first direction, the stacked internal electrodes being alternately exposed from the end faces facing each other in a second direction; a base metal layer in contact with a portion of the plurality of internal electrodes exposed from the end faces and provided at an end face side of a surface of the element body connected to the end face; a glass layer provided at the end face side between a tip of the base metal layer and the element body and on the opposite side of the end face; and a plating layer at the end face so as to sandwich the base metal layer and the glass layer between the element body and the element body, and which forms an external electrode together with the base metal layer.

[0007] In the above-described structure, the glass layer may contain silicon oxide.

[0008] In the above configuration, the base metal layer may include a first layer that sandwiches the glass layer with the element body at the end, and a second layer that has a lower Si concentration than the first layer and is in contact with the end surface.

[0009] In the above configuration, the first layer may sandwich the second layer between itself and the end face.

[0010] In the above configuration, the first layer may not be provided on the end surface.

[0011] In the above configuration, the plating layer may be configured not to come into contact with the element body.

[0012] The present invention provides a method for manufacturing a multilayer ceramic electronic component, comprising the steps of: preparing an element body in which a plurality of internal electrodes and a plurality of dielectric layers primarily composed of ceramic are alternately stacked in a first direction, the stacked internal electrodes having end faces that are alternately exposed and facing each other in a second direction; applying a first conductor paste containing glass powder containing silicon oxide to an end portion of a surface of the element body that will be connected to the end face, the end portion being closer to the end face; applying a second conductor paste having a lower Si concentration than the first conductor paste to the end face; sintering the first conductor paste and the second conductor paste to form a base metal layer that is in contact with a portion of the plurality of internal electrodes exposed from the end face and is provided at the end portion; and a glass layer containing silicon oxide that is provided between a tip of the base metal layer and the element body at the end portion and extends to the opposite side of the end face; and forming a plating layer that is provided at the end portion so as to sandwich the base metal layer and the glass layer between the element body and the element body, the plating layer forming an external electrode together with the base metal layer.

[0013] In the above configuration, the step of applying the first conductive paste includes a step of forming the first conductive paste on the end portion so that the first conductive paste is not provided on the end surface, and the step of applying the second conductive paste can be configured to be performed after the step of applying the first conductive paste.

[0014] In the above configuration, the step of applying the first conductive paste may be performed after the step of applying the second conductive paste, and may include a step of applying the first conductive paste so as to cover the second conductive paste.

[0015] The present invention is a method for manufacturing a multilayer ceramic electronic component, comprising the steps of: preparing an element body in which a plurality of internal electrodes and a plurality of dielectric layers primarily composed of ceramic are alternately stacked in a first direction, the stacked internal electrodes having end faces that are alternately exposed and facing each other in a second direction; applying a paste containing silicon oxide to an end portion of a surface of the element body that is connected to the end face, without applying it to the end face; applying a conductive paste to the end face of the element body and onto the paste; and baking the paste and the conductive paste to form a base metal layer that is in contact with a portion of the plurality of internal electrodes exposed from the end face and is provided at the end face, and a glass layer containing silicon oxide that is provided between the tip of the base metal layer at the end face and the element body and extends to the opposite side of the end face; and forming a plating layer that is provided at the end face so as to sandwich the base metal layer and the glass layer between the element body and the element body, and that forms an external electrode together with the base metal layer.

[0016] According to the present invention, deterioration of the internal electrodes can be suppressed.

[0017] FIG. 1 is a partial cross-sectional perspective view of the multilayer ceramic capacitor according to Embodiment 1. FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1. FIG. 3 is a cross-sectional view taken along line B-B in FIG. 1. FIG. 4 is a flowchart showing a method for manufacturing the multilayer ceramic capacitor according to Embodiment 1. FIG. 5A is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to Embodiment 1. FIG. 5B is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to Embodiment 1. FIG. 6A is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to Embodiment 1. FIG. 6B is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to Embodiment 1. FIG. 7 is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to Embodiment 1. FIG. 8 is a cross-sectional view of a comparative multilayer ceramic capacitor. FIG. 9 is a cross-sectional view of the multilayer ceramic capacitor according to Embodiment 1. FIG. 10 is a cross-sectional view of a multilayer ceramic capacitor according to a modified example of Embodiment 1. FIG. 11 is a cross-sectional view of a multilayer ceramic capacitor according to Embodiment 2. FIG. 12A is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to Embodiment 2. FIG. 12B is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to Embodiment 2. FIG. 13A is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to Embodiment 2. FIG. 13B is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to Embodiment 2. Fig. 14 is a cross-sectional view of a multilayer ceramic capacitor according to a modified example of embodiment 2. Fig. 15 is a cross-sectional view of a multilayer ceramic capacitor according to embodiment 3. Fig. 16A is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to embodiment 3. Fig. 16B is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to embodiment 3. Fig. 17 is a cross-sectional view showing a method for manufacturing the multilayer ceramic capacitor according to embodiment 3.

[0018] Hereinafter, with reference to the drawings, an embodiment will be described using a multilayer ceramic capacitor as an example of a multilayer ceramic electronic component.

[0019] 1 is a partial cross-sectional perspective view of a multilayer ceramic capacitor 100 according to embodiment 1. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. Fig. 3 is a cross-sectional view taken along line BB in Fig. 1.

[0020] 1 to 3 , the Z direction (first direction) is the stacking direction in which the dielectric layers 14 and the internal electrodes 12a and 12b are stacked, and is the direction in which the bottom surface 55 and top surface 56 of the element body 10 face each other. The X direction (second direction) is the length direction of the element body 10, and is the direction in which a pair of end surfaces 51 and 52 of the element body 10 face each other. The Y direction (third direction) is the width direction of the internal electrodes 12a and 12b, and is the direction in which a pair of side surfaces 53 and 54 of the element body 10 face each other. The X direction, Y direction, and Z direction intersect or are perpendicular to each other.

[0021] The multilayer ceramic capacitor 100 includes a substantially rectangular parallelepiped element body 10 and external electrodes 20a and 20b. The element body 10 includes a plurality of dielectric layers 14, a plurality of internal electrodes 12a and 12b, and a cover dielectric layer 16. The plurality of internal electrodes 12a and the plurality of internal electrodes 12b are alternately stacked. One of the plurality of dielectric layers 14 is provided between one of the plurality of internal electrodes 12a and one of the plurality of internal electrodes 12b. The outermost layers in the stacking direction (Z direction) of the laminate, in which the dielectric layer 14 and the internal electrodes 12a and 12b are stacked, are the internal electrodes 12a and 12b, and the bottom and top surfaces of the laminate are covered by cover dielectric layers 16. The regions sandwiching the plurality of internal electrodes 12a and 12b in the Y direction are side margin regions 18.

[0022] The internal electrodes 12a and 12b are alternately exposed on the end faces 51 and 52. The internal electrode 12a is exposed, but the internal electrode 12b is not, on the end face 51. The internal electrode 12b is exposed, but the internal electrode 12a is not, on the end face 52. That is, the internal electrodes 12a and 12b are connected to different end faces 51 and 52.

[0023] The external electrode 20a contacts the internal electrode 12a exposed from the element body 10 at the end face 51. The external electrode 20b contacts the internal electrode 12b exposed from the element body 10 at the end face 52. The external electrode 20a covers the end faces 40 in the -X direction of the side faces 53, 54, bottom face 55, and top face 56 of the element body 10 in addition to the end face 51. The end faces 40 are the portions of the faces of the element body 10 connected to the end faces 51 and 52 that are on the end face 51 and 52 side. The external electrode 20b contacts the internal electrode 12b at the end face 52. The external electrode 20b covers the end faces 40 in the +X direction of the side faces 53, 54, bottom face 55, and top face 56 of the element body 10 in addition to the end face 52.

[0024] Each of the external electrodes 20a and 20b includes a base metal layer 22 and a plating layer 24 provided to cover the base metal layer 22. The base metal layer 22 includes metal layers 22a and 22b. The metal layer 22a is provided on the end portion 40. A glass layer 21 is provided between the metal layer 22a and the element body 10. The glass layer 21 is exposed from the tip of the metal layer 22a. The metal layer 22b is provided on the end faces 51 and 52. The glass layer 21 is not provided on the end faces 51 and 52, and the metal layer 22b is in contact with the internal electrode 12a or 12b. The plating layer 24 is provided to cover the base metal layer 22. The tip of the plating layer 24 is in contact with the glass layer 21 and not with the element body 10.

[0025] The size of the multilayer ceramic capacitor 100 is, for example, 0.25 mm in length (length in the X direction), 0.125 mm in width (width in the Y direction), and 0.125 mm in height (height in the Z direction), or 0.4 mm in length, 0.2 mm in width, and 0.2 mm in height, or 0.6 mm in length, 0.3 mm in width, and 0.3 mm in height, or 1.0 mm in length, 0.5 mm in width, and 0.5 mm in height, or 3.2 mm in length, 1.6 mm in width, and 1.6 mm in height, or 4.5 mm in length, 3.2 mm in width, and 2.5 mm in height, but is not limited to these sizes.

[0026] The internal electrodes 12a and 12b are primarily composed of base metals such as nickel (Ni), copper (Cu), and tin (Sn). The internal electrodes 12a and 12b may also be made of precious metals such as platinum (Pt), palladium (Pd), silver (Ag), and gold (Au), or alloys containing these metals. The thickness of the internal electrodes 12a and 12b is, for example, 0.1 μm to 1 μm.

[0027] The dielectric layer 14 is, for example, a compound represented by the general formula ABO ３ The main phase is a ceramic material having a perovskite structure represented by the formula: ３－α For example, the ceramic material includes barium titanate (BaTiO ３ ), calcium zirconate (CaZrO ３ ), calcium titanate (CaTiO ３ ), strontium titanate (SrTiO ３ ), magnesium titanate (MgTiO ３ ), and Ba, which forms a perovskite structure １-ｘ－ｙ Ca ｘ Sr ｙ Ti １－ｚ Zr ｚ O ３ (0≦x≦1, 0≦y≦1, 0≦z≦1) and the like. １-ｘ－ｙ Ca ｘ Sr ｙ Ti １－ｚ Zr ｚ O ３ Examples of the ceramic materials include barium strontium titanate, barium calcium titanate, barium zirconate, barium titanate zirconate, calcium titanate zirconate, and barium calcium titanate zirconate. For example, the dielectric layer 14 contains 90 at% or more of the main component ceramic. The thickness of the dielectric layer 14 is, for example, 0.3 μm or more and 2 μm or less.

[0028] An additive may be added to the dielectric layer 14. Examples of additives to the dielectric layer 14 include oxides of zirconium (Zr), hafnium (Hf), magnesium (Mg), manganese (Mn), molybdenum (Mo), vanadium (V), chromium (Cr), rare earth elements (yttrium (Y), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), and ytterbium (Yb)), oxides containing cobalt (Co), nickel (Ni), lithium (Li), boron (B), sodium (Na), potassium (K), or silicon (Si), or glasses containing cobalt, nickel, lithium, boron, sodium, potassium, or silicon.

[0029] The composition of the main ceramic component of the cover dielectric layer 16 may be the same as or different from the main ceramic component of the dielectric layer 14 .

[0030] The base metal layer 22 is primarily composed of a metal such as copper, nickel, aluminum (Al), or zinc (Zn), or an alloy of two or more of these metals (e.g., an alloy of copper and nickel), and contains ceramics such as a glass component for densifying the base metal layer 22 and a co-material for controlling the sinterability of the external electrodes 20a and 20b. The glass component is an oxide of barium (Ba), strontium (Sr), calcium (Ca), zinc, aluminum, silicon, boron, or the like. The co-material is, for example, a ceramic component primarily composed of the same material as the main component of the dielectric layer 14. The silicon oxide concentration of the metal layer 22a is higher than that of the metal layer 22b. Hereinafter, the silicon oxide concentration is referred to as SiO ２ The thickness of the underlying metal layer 22 is, for example, 3 μm to 50 μm. The silicon oxide concentration of the metal layers 22a and 22b is, for example, 5 mol % or more.

[0031] As will be described later, it can be confirmed that the silicon oxide concentration of metal layer 22a is higher than that of metal layer 22b by measuring the concentration of Si element (Si concentration) (at %) in metal layers 22a and 22b using, for example, a scanning transmission electron microscope (STEM)-energy dispersive X-ray spectroscopy (EDS) method. The Si concentration of metal layer 22a is higher than that of metal layer 22b.

[0032] The plating layer 24 is primarily composed of a metal such as copper, nickel, aluminum, zinc, or tin, or an alloy of two or more of these metals. The plating layer 24 may be a plating layer of a single metal component, or may be a plurality of plating layers of different metal components. Furthermore, a film of conductive resin such as epoxy resin or urethane resin may be formed on the surface of the plating layer 24. The thickness of the plating layer 24 is, for example, 5 μm to 15 μm.

[0033] The glass layer 21 is mainly composed of silicon oxide (for example, silicon dioxide) and may contain other metal oxides. The thickness of the glass layer 21 is, for example, 0.1 μm to 5 μm.

[0034] (Manufacturing Method of First Embodiment) A method for manufacturing the multilayer ceramic capacitor 100 will be described below. Fig. 4 is a flowchart showing a method for manufacturing the multilayer ceramic capacitor of the first embodiment.

[0035] (Green Sheet Formation Process) First, a green sheet is formed (Step S10). In Step S10, a dielectric material is prepared by adding various additive compounds (such as sintering aids) to ceramic powder, for example. A binder such as polyvinyl butyral (PVB) resin, an organic solvent such as ethanol or toluene, and a plasticizer are added to the prepared dielectric material and wet-mixed to produce a slurry. The produced slurry is then applied to a substrate using, for example, a die coater method or a doctor blade method, to form a green sheet. The substrate is, for example, a PET (polyethylene terephthalate) film. The green sheet is then dried.

[0036] (Pattern Forming Process) Next, metal patterns that will become the internal electrodes 12a and 12b are formed on the green sheet (Process S12). In Process S12, a conductive paste containing an organic binder for forming the internal electrodes is printed on the green sheet on the substrate, for example, using gravure printing. This results in multiple metal patterns corresponding to the internal electrodes 12a and 12b being formed on the green sheet at intervals. The conductive paste contains a metal powder, such as nickel powder, as a main component, a binder, and an organic solvent. Ceramic particles may also be added to the conductive paste as a co-material.

[0037] (Laminating Step) Next, the green sheets are laminated (Step S14). In Step S14, green sheets on which metal patterns that become the internal electrodes 12 a and 12 b are printed are laminated to form a laminate sheet. Green sheets corresponding to the cover dielectric layers 16 are laminated on both end faces of the laminate sheet in the lamination direction.

[0038] (Compression Bonding Step) Subsequently, the laminated sheet is compressed (Step S16). In Step S16, the laminated sheet formed in Step S14 is pressed to compress the green sheets together. As the compression bonding means, for example, a hydrostatic press is used.

[0039] (Cutting Step) Next, the laminated sheet is cut (step S18). In step S18, a cutting blade is used to cut the laminated sheet in the stacking direction along predetermined cutting lines, thereby preparing a plurality of element bodies 10. In each element body 10, the internal electrode 12a is exposed from an end face 51, and the internal electrode 12b is exposed from an end face 52. After step S18, the element body 10 may be polished by a technique such as barrel polishing. This rounds the corners of the element body 10.

[0040] (Firing Step) Next, the element body 10 is fired (Step S20). In Step S20, the element body 10 is subjected to a binder removal process in a nitrogen gas atmosphere at 250°C to 500°C, and then fired in a reducing atmosphere at 1300°C to 1400°C for about one hour. This sinters the particles of the element body 10 and the internal electrodes 12a and 12b.

[0041] (External Electrode Forming Step) Subsequently, the external electrodes 20a and 20b are formed (step S25). Step S25 includes steps S22, S24, and S26. Figures 5A to 7 are cross-sectional views showing the method for manufacturing the multilayer ceramic capacitor according to the first embodiment.

[0042] First, paste 30 is applied to element body 10 (step S22). As shown in FIG. 5A, paste 30 is applied to end portion 40 and end surface 51 of element body 10 by, for example, dipping. Paste 30 contains a metal powder such as copper powder as a main component, glass powder (glass frit) containing silicon oxide, a binder, and an organic solvent. The glass powder may contain at least one metal oxide selected from barium oxide, zinc oxide, calcium oxide, aluminum oxide, magnesium oxide, boron oxide, and the like. SiO in the glass powder in paste 30 ２ The concentration is, for example, 30 mol % to 98 mol %.

[0043] 5B, the paste 30 applied to the end surface 51 is removed using blotting paper or the like, so that the paste 30 is provided only on the end portion 40.

[0044] 6A, paste 32 is applied to the end surface 51 of element body 10 by, for example, dipping. Paste 32 contains a metal powder, such as copper powder, as a main component, glass powder, a binder, and an organic solvent. The glass powder contains almost no silicon oxide, and contains at least one metal oxide selected from barium oxide, zinc oxide, calcium oxide, aluminum oxide, magnesium oxide, and boron oxide. SiO in the glass powder in paste 32 ２ The concentration of SiO in the glass powder in the paste 32 ２ The concentration is lower than that of the above, for example, 5 mol % to 30 mol %.

[0045] Next, pastes 30 and 32 are sintered (step S24). In step S24, pastes 30 and 32 are baked in a nitrogen atmosphere at 750° C. to 850° C., which is lower than the firing temperature in step S22. In this way, pastes 30 and 32 are baked onto element body 10.

[0046] As shown in FIG. 6B , by firing the paste 30, a glass layer 21 and a metal layer 22a are formed from the paste 30. The glass layer 21 contacts the element body 10 and is primarily composed of silicon oxide. In addition to silicon oxide, the glass layer 21 may also contain components of the glass powder in the paste 30 and oxides of elements in the element body 10. The glass layer 21 may also contain metals such as copper in the paste 30, but has a higher resistivity than the metal layer 22a and is an insulator. The glass layer 21 is an inorganic insulator containing silicon oxide and a metal oxide and is amorphous. The metal layer 22a sandwiches the glass layer 21 between the element body 10 and the glass layer 21. The tip of the glass layer 21 protrudes beyond the tip of the metal layer 22a. In other words, the tip portion of the glass layer 21 is exposed beyond the metal layer 22a. The metal layer 22a is primarily composed of a metal such as copper and contains components of the glass powder in the paste 30.

[0047] A metal layer 22b is formed from the paste 32 on the end surface 51 of the element body 10. The metal layer 22b is mainly composed of a metal such as copper, and contacts the internal electrode 12a exposed from the end surface 51 of the element body 10. The metal layer 22b is mainly composed of a metal such as copper, and contains components of the glass powder in the paste 32. The silicon oxide concentration in the metal layer 22b is lower than the silicon oxide concentration in the metal layer 22a. The metal layers 22a and 22b form the base metal layer 22.

[0048] Next, a plating layer 24 is formed (step S26). As shown in Fig. 7, in step S26, the plating layer 24 is formed to cover the base metal layer 22. The base metal layer 22 and the plating layer 24 form the external electrodes 20a and 20b. The plating layer 24 is, for example, a layer mainly composed of copper, a layer mainly composed of nickel, and a layer mainly composed of tin, from the base metal layer 22 side. The base metal layer 22 and the plating layer 24 form the external electrodes 20a and 20b.

[0049] (Comparative Multilayer Ceramic Capacitor) FIG. 8 is a cross-sectional view of a comparative multilayer ceramic capacitor, showing an enlarged cross-section of the vicinity of the corner between the end face 51 and the top surface 56. As shown in FIG. 8 , the comparative multilayer ceramic capacitor does not have a glass layer 21, and the base metal layer 22 contacts the end 40 of the element body 10. The plating layer 24 is provided to cover the base metal layer 22. When forming the plating layer 24, moisture or corrosive components in the plating solution may penetrate the interface between the element body 10 and the base metal layer 22, as indicated by arrow 50, and then penetrate into the end face 51. This may cause corrosion of the internal electrodes 12a, etc. Furthermore, when mounting the multilayer ceramic capacitor, solder flux may penetrate into the interface between the element body 10 and the base metal layer 22. This may result in reduced resistance to plating solutions and moisture resistance.

[0050] FIG. 9 is a cross-sectional view of the multilayer ceramic capacitor of the first embodiment, showing an enlarged cross-sectional view of the vicinity of a corner between an end face 51 and a top surface 56. As shown in FIG. 9 , in the multilayer ceramic capacitor of the first embodiment, the base metal layer 22 contacts the multiple internal electrodes 12a exposed from the end face 51 and is provided at the end 40 of the element body 10. As shown in the dashed-line area 57, the glass layer 21 is provided from between the tip of the base metal layer 22 and the element body 10 at the end 40 to the opposite side of the end face 51. The plating layer 24 is provided at the end 40 so as to sandwich the base metal layer 22 and the glass layer 21 between the element body 10 and the base metal layer 22. As a result, when the plating layer 24 is formed, the glass layer 21 acts as a barrier against moisture or corrosive components in the plating solution, preventing the moisture or corrosive components from penetrating the interface between the element body 10 and the base metal layer 22. This prevents corrosion of the internal electrodes 12a and the like. Furthermore, when mounting the multilayer ceramic capacitor, it is possible to prevent solder flux from penetrating into the interface between the element body 10 and the base metal layer 22. In this way, it is possible to improve resistance to plating liquid and moisture resistance.

[0051] The glass layer 21 contains silicon oxide. The glass layer 21 containing silicon oxide has good adhesion to the base metal layer 22 and the element body 10. This makes it possible to prevent moisture and corrosive components from penetrating through the interface between the glass layer 21 and the element body 10 and the interface between the glass layer 21 and the base metal layer 22. To improve adhesion, the SiO ２ The concentration is preferably 50 mol % or more, more preferably 75 mol % or more, and even more preferably 90 mol % or more.

[0052] As shown in Figures 5A and 5B, paste 30 (first conductor paste) containing powder containing silicon oxide is applied so as to contact end 40 of element body 10. As shown in Figure 6A, paste 32 (second conductor paste) having a lower silicon oxide concentration than paste 30 is applied so as to contact end surface 51. As shown in Figure 6B, pastes 30 and 32 are sintered to form base metal layer 22 and glass layer 21. In this way, paste 30 applied to end 40 contains glass powder containing silicon oxide. As a result, glass layer 21 containing silicon oxide can be formed between element body 10 and metal layer 22a by a baking process.

[0053] If paste 30 containing glass powder with a high silicon oxide content is applied to the end surface 51, the contact resistance between the internal electrode 12a and the base metal layer 22 increases. Therefore, as shown in FIG. 5B , paste 30 is applied to the end surface 40 so that paste 30 is not applied to the end surface 51. Then, as shown in FIG. 6A , paste 32 is applied so as to contact the end surface 51. Then, as shown in FIG. 6B , a baking process is performed. As a result, the paste 30 forms a glass layer 21 provided on the end surface 40 and a metal layer 22a (first layer) that sandwiches the glass layer 21 between the element body 10 at the end surface 40. A metal layer 22b (second layer) that has a lower silicon oxide concentration than the metal layer 22a and contacts the end surface 51 is formed. Furthermore, the metal layer 22a is not provided on the end surface 51. Because the metal layer 22b with a low silicon oxide concentration contacts the internal electrode 12a, the contact resistance between the internal electrode 12a and the base metal layer 22 can be reduced.

[0054] The baking temperature of the paste 30 containing glass powder with a high silicon oxide content is higher than the baking temperature of the paste 32 containing glass powder with a low silicon oxide content. Therefore, the baking process of the paste 30 and the baking process of the paste 32 may be performed separately, and the baking temperature of the paste 30 containing silicon oxide may be set higher than the baking temperature of the paste 32.

[0055] As will be described later, it is possible to confirm that the silicon oxide concentration of paste 30 is higher than that of paste 32 by measuring the Si concentration in pastes 20 and 32 using, for example, STEM-EDS. The Si concentration of paste 30 is higher than that of paste 32.

[0056] The silicon oxide concentration in the metal layer 22a is preferably at least twice, more preferably at least three times, and even more preferably at least ten times, the silicon oxide concentration in the metal layer 22b. The silicon oxide concentration in the metal layer 22b is, for example, 5 mol % to 30 mol %. The silicon oxide concentration in the metal layer 22a is, for example, 50 mol % to 99 mol %. The silicon oxide concentrations in the metal layers 22a and 22b are determined by the SiO in the glass (i.e., inorganic insulator containing silicon oxide and metal oxide) contained in the metal layers 22a and 22b. ２ is the molar ratio.

[0057] (Modification of Embodiment 1) Fig. 10 is a cross-sectional view of a multilayer ceramic capacitor according to a modification of Embodiment 1. As shown in Fig. 10, in a multilayer ceramic capacitor 102 according to the modification of Embodiment 1, the metal layer 22b is provided so as to cover the metal layer 22a at the end portion 40. The other configuration is the same as that of Embodiment 1, and therefore description thereof will be omitted. As in the modification of Embodiment 1, the metal layer 22b may cover at least a portion of the metal layer 22a at the end portion 40.

[0058] (Embodiment 2) Fig. 11 is a cross-sectional view of a multilayer ceramic capacitor according to embodiment 2. As shown in Fig. 11, in a multilayer ceramic capacitor 104 according to embodiment 2, a metal layer 22b is provided so as to contact an end face 51, and is barely provided on an end portion 40. A glass layer 21 is provided on an end portion 40 of an element body 10. A metal layer 22a is provided so as to contact the metal layer 22b on the end face 51 and the glass layer 21 on the end portion 40. A plating layer 24 is provided so as to cover the base metal layer 22, and its tip contacts the glass layer 21 but does not contact the element body 10. The other configurations are the same as those of embodiment 1, and therefore description thereof will be omitted.

[0059] (Manufacturing Method of Embodiment 2) First, the steps up to the firing step of step S20 in FIG. 4 are performed. FIGS. 12A to 13B are cross-sectional views showing a manufacturing method of a multilayer ceramic capacitor according to embodiment 2. After the firing step, in step S22, as shown in FIG. 12A, paste 32 is applied to end surface 51 of element body 10. At this time, paste 32 is hardly applied to end portion 40. As shown in FIG. 12B, paste 30 is applied so as to cover paste 32 on end surface 51 and end portion 40. The method of applying pastes 30 and 32 is, for example, a dipping method.

[0060] As shown in Fig. 13A, by baking pastes 30 and 32, a glass layer 21 and a metal layer 22a are formed from paste 30. Glass layer 21 covers end portion 40, and metal layer 22a covers glass layer 21 and metal layer 22b. As shown in Fig. 13B, plating layer 24 is formed to cover metal layer 22a. External electrode 20a is formed by base metal layer 22 and plating layer 24.

[0061] In the second embodiment, as shown in Fig. 12A, paste 32 is applied to contact the end face 51, and then paste 30 is applied to cover the paste 32 as shown in Fig. 12B. Then, as shown in Fig. 13A, a baking process is performed. As a result, a metal layer 22a (first layer) is formed at the end 40, sandwiching the glass layer 21 between the element body 10 and the metal layer 22a. A metal layer 22b (second layer) having a lower silicon oxide concentration than the metal layer 22a is formed, contacting the end face 51. The metal layer 22a is also provided so as to sandwich the metal layer 22b between the metal layer 22a and the end face 51. Because the metal layer 22b, which has a lower silicon oxide concentration, contacts the internal electrode 12a, the connectivity between the internal electrode 12a and the underlying metal layer 22 is improved.

[0062] (Modification of Embodiment 2) Fig. 14 is a cross-sectional view of a multilayer ceramic capacitor according to a modification of Embodiment 2. As shown in Fig. 14, in a multilayer ceramic capacitor 106 according to the modification of Embodiment 2, at the end portion 40, the metal layer 22b is provided so as to cover a portion of the end portion 40. The other configurations are the same as those of Embodiment 2, and therefore description thereof will be omitted. As in the modification of Embodiment 2, at the end portion 40, the metal layer 22b may cover a portion of the end portion 40. It is sufficient that the metal layer 22a is provided so as to cover the tip of the metal layer 22b.

[0063] (Embodiment 3) Fig. 15 is a cross-sectional view of a multilayer ceramic capacitor according to embodiment 3. As shown in Fig. 15, in a multilayer ceramic capacitor 108 according to embodiment 3, the base metal layer 22 has one metal layer. The base metal layer 22 contacts the internal electrodes 12a and 12b at end faces 51 and 52, respectively, and sandwiches the glass layer 21 between the base metal layer 22 and the element body 10 at end 40. The plating layer 24 is provided so as to cover the base metal layer 22, and its tip contacts the glass layer 21 but does not contact the element body 10. The other configuration is the same as that of embodiment 1, and therefore description thereof will be omitted.

[0064] (Manufacturing Method of Embodiment 3) First, the firing step of step S20 in FIG. 4 is performed. FIGS. 16A to 17 are cross-sectional views showing a manufacturing method of a multilayer ceramic capacitor according to Embodiment 3. After the firing step, in step S22, paste is applied to element body 10. As shown in FIG. 16A, paste 34 is applied to end portion 40 of element body 10. Similar to FIGS. 5A and 5B, paste 34 is applied to end portion 40 and end surface 51 using, for example, a dipping method. The applied paste 34 is then removed from end surface 51. Paste 34 does not contain metal powder, but contains glass powder containing silicon oxide, a binder, and an organic solvent. The glass powder may contain at least one metal oxide, such as barium oxide, zinc oxide, calcium oxide, aluminum oxide, magnesium oxide, or boron oxide.

[0065] As shown in FIG. 16B , paste 36 is applied to end 40 and end surface 51 by, for example, dipping. The tip of paste 36 is located closer to end surface 51 than the tip of paste 34. The tip of paste 34 is exposed from paste 36. Paste 36 contains metal powder such as copper powder, glass powder, a binder, and an organic solvent. The glass powder contains at least one metal oxide selected from barium oxide, zinc oxide, calcium oxide, aluminum oxide, magnesium oxide, boron oxide, and the like. The glass powder may contain silicon oxide, but the silicon oxide concentration of paste 36 is lower than the silicon oxide concentration of paste 34.

[0066] Next, a baking process is performed in step S24. As shown in FIG. 17 , a glass layer 21 is formed from the paste 34, and a base metal layer 22 is formed from the paste 36. The glass layer 21 is an amorphous inorganic insulator containing silicon oxide and metal oxide. The base metal layer 22 is primarily composed of a metal such as copper and sandwiches the glass layer 21 between the element body 10. The tip portion of the glass layer 21 is exposed from the base metal layer 22. Next, in step S26, a plating layer 24 is formed to cover the base metal layer 22. The tip portion of the plating layer 24 contacts the glass layer 21 but does not contact the element body 10. The structure of the plating layer 24 is the same as in embodiment 1. The base metal layer 22 and the plating layer 24 form the external electrodes 20a and 20b. Note that the paste 36 may be baked after the paste 34 is baked.

[0067] In embodiment 2, as shown in Fig. 16A, paste 34 containing silicon oxide but no metal is applied to edge 40 of element body 10 without being applied to edge surface 51 of element body 10. As shown in Fig. 16B, paste 36 (conductive paste) is applied to edge surface 51 of element body 10 and on paste 34. As shown in Fig. 17, pastes 34 and 36 are baked to form base metal layer 22 and glass layer 21. This allows glass layer 21 containing silicon oxide as a main component to be formed on edge 40.

[0068] In FIG. 17, the glass layer 21 is formed over the entire edge 40, but the glass layer 21 may be provided at the tip of the base metal layer 22 as in FIG.

[0069] In this embodiment, the Si concentration is measured using, for example, a scanning transmission electron microscope (STEM)-energy dispersive X-ray spectroscopy (EDS) method. An electron beam is irradiated onto the glass, and the molar ratio of Si to the entire glass is calculated from the peaks of Si and metal elements in the glass, thereby determining the Si concentration. A similar method to that described above is also used when measuring the Si concentration of a conductive paste. The Si concentration may be measured at any location in the corresponding layer. A certain component containing a certain element or molecule as a main component means that the certain element or molecule is contained in the certain component to an extent that the effect of the embodiment is achieved, and the concentration of the certain element or molecule in the certain component is, for example, 50 mol% or more, 80 mol% or more, or 90 mol% or more.

[0070] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims.

[0071] REFERENCE SIGNS LIST 10 Element body 12a, 12b Internal electrode 14 Dielectric layer 16 Cover dielectric layer 18 Side margin region 20a, 20b External electrode 22 Undercoat metal layer 22a, 22b Metal layer 24 Plating layer 30, 32, 34, 36 Paste 40 End 51, 52 End face 53, 54 Side face 55 Lower face 56 Upper face

Claims

1. A multilayer ceramic electronic component comprising: an element body in which a plurality of internal electrodes and a plurality of dielectric layers mainly composed of ceramic are alternately stacked in a first direction, the stacked internal electrodes being alternately exposed from the end faces facing each other in a second direction; a base metal layer in contact with a portion of the plurality of internal electrodes exposed from the end face and provided on an end face side of a surface of the element body that is connected to the end face; a glass layer provided at the end face between a tip of the base metal layer and the element body and on the opposite side to the end face; and a plating layer provided at the end face so as to sandwich the base metal layer and the glass layer between the element body and the base metal layer, the plating layer forming an external electrode together with the base metal layer.

2. The multilayer ceramic electronic component according to claim 1, wherein said glass layer contains silicon oxide.

3. The multilayer ceramic electronic component according to claim 2, wherein the base metal layer comprises a first layer that sandwiches the glass layer between the element body and the end face, and a second layer that has a lower Si concentration than the first layer and is in contact with the end face.

4. The multilayer ceramic electronic component according to claim 3, wherein said first layer sandwiches said second layer between said end faces.

5. The multilayer ceramic electronic component according to claim 3, wherein said first layer is not provided on said end faces.

6. The multilayer ceramic electronic component according to any one of claims 1 to 5, wherein the plating layer is not in contact with the element body.

7. A method for manufacturing a multilayer ceramic electronic component, comprising: preparing an element body in which a plurality of internal electrodes and a plurality of dielectric layers mainly composed of ceramic are alternately stacked in a first direction, the stacked plurality of internal electrodes having end faces that are alternately exposed and facing each other in a second direction; applying a first conductor paste containing glass powder containing silicon oxide to contact an end portion of a surface of the element body that is to be connected to the end face, the end face side; applying a second conductor paste having a lower Si oxide concentration than the first conductor paste to contact the end face; sintering the first conductor paste and the second conductor paste to form a base metal layer that is in contact with a portion of the plurality of internal electrodes exposed from the end face and is provided on the end portion, and a glass layer containing silicon oxide that is provided between a tip of the base metal layer at the end portion and the element body and on the opposite side to the end face; and forming a plating layer that is provided at the end portion so as to sandwich the base metal layer and the glass layer between the element body and the element body, the plating layer forming an external electrode together with the base metal layer.

8. A method for manufacturing a multilayer ceramic electronic component as described in claim 7, wherein the step of applying the first conductive paste includes a step of forming the first conductive paste on the end portion so that the first conductive paste is not provided on the end face, and the step of applying the second conductive paste is performed after the step of applying the first conductive paste.

9. A method for manufacturing a multilayer ceramic electronic component as described in claim 7, wherein the step of applying the first conductive paste is performed after the step of applying the second conductive paste, and includes a step of applying the first conductive paste so as to cover the second conductive paste.

10. A method for manufacturing a multilayer ceramic electronic component, comprising: preparing an element body in which a plurality of internal electrodes and a plurality of dielectric layers mainly composed of ceramic are alternately stacked in a first direction, the stacked internal electrodes having end faces that are alternately exposed and facing each other in a second direction; applying a paste containing silicon oxide to an end face of the element body that is connected to the end face of the element body without applying the paste containing silicon oxide to the end face; applying a conductor paste to the end face of the element body and onto the paste; baking the paste and the conductor paste to form a base metal layer that is in contact with a portion of the plurality of internal electrodes exposed from the end face and is provided on the end face, and a glass layer containing silicon oxide that is provided between the tip of the base metal layer at the end face and the element body and extends to the opposite side of the end face; and forming a plating layer at the end face so as to sandwich the base metal layer and the glass layer between the element body and the element body, the plating layer forming an external electrode together with the base metal layer.

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