Laminated ceramic electronic component and method for manufacturing same

Abstract

This laminated ceramic electronic component includes: a ceramic body including a pair of main surfaces that face each other along a first axis direction and on which dielectric layers and internal electrodes are alternately laminated along the first axis direction, a pair of side surfaces that face each other in a second axis direction orthogonal to the first axis direction, and a pair of end surfaces that face each other in a third axis direction orthogonal to the first axis direction and the second axis direction; and a pair of external electrodes provided respectively on third-axis-direction ends of the ceramic body and provided so as to be conductive with internal electrodes each drawn out onto the surface of a different third-axis- direction end of the ceramic body. The internal electrodes are formed from Ni or a metal having Ni as a main component and, in plan view in which the ceramic body is viewed from the first axis direction, include, in at least a portion of the periphery, a diffusion region including a metal different than the main component of the internal electrodes.

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] A multilayer ceramic capacitor, which is one type of multilayer ceramic electronic component, includes a laminate in which multiple dielectric layers and multiple internal electrodes are alternately stacked, and a pair of external electrodes formed on the surface of the laminate so as to be electrically connected to the internal electrodes extended to the surface of the laminate. The external electrodes are plated on a base layer. Patent Document 1 describes that hydrogen generated during the plating process is absorbed by the internal electrodes, reducing the dielectric layers and thereby deteriorating the insulation resistance. Patent Document 1 also describes adding Ni (nickel) as a metal that suppresses hydrogen absorption when using internal electrodes primarily composed of precious metals. Meanwhile, Patent Document 2 describes that even when Ni is used in the internal electrodes, the influence of hydrogen causes degradation of insulation resistance.

[0003] JP 1-80011 A JP 2016-66783 A

[0004] In order to suppress the influence of hydrogen, it is desirable to configure the internal electrodes so that even if hydrogen penetrates from the external electrodes, the insulation resistance will not be reduced by hydrogen.

[0005] Furthermore, with the recent increasing demand for miniaturization of components, it has become necessary to design the internal and external electrodes in close proximity to each other, making it essential to take measures to prevent current leakage between the internal and external electrodes.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide a multilayer ceramic electronic component that can prevent the component from breaking down due to current leakage even when hydrogen penetrates into the component.

[0007] The present invention solves the above problems by disposing a different metal component on the outer periphery of the internal electrode.

[0008] Specifically, in order to solve the above problem, the multilayer ceramic electronic component disclosed in this specification comprises a ceramic body in which dielectric layers and internal electrodes are alternately stacked along a first axial direction, and which has a pair of main surfaces opposing each other along the first axial direction, a pair of side surfaces opposing each other in a second axial direction perpendicular to the first axial direction, and a pair of end faces opposing each other in a third axial direction perpendicular to the first and second axial directions; and a pair of external electrodes respectively provided at ends of the ceramic body in the third axial direction and arranged to be conductive with the internal electrodes respectively extended to different ends of the ceramic body in the third axial direction, and the internal electrodes can be configured to have a diffusion region in at least a portion of their outer peripheries containing a metal different from the main component of the internal electrodes.

[0009] In the multilayer ceramic electronic component having the above configuration, the diffusion region may be formed at an end of the internal electrode that appears in a cross section parallel to a plane including the first axis direction and the second axis direction.

[0010] In addition, in the multilayer ceramic electronic component having the above configuration, the diffusion region may be formed at an end of the internal electrode that appears in a cross section parallel to a plane including the first axis direction and the third axis direction.

[0011] In the multilayer ceramic electronic component having the above configuration, the element contained in the diffusion region may be at least one of Pt, Pd, Au, Ag, Cu, Sn, Fe, Zn, and Al.

[0012] In the multilayer ceramic electronic component having the above configuration, the element contained in the diffusion region may be at least one of Sn, Fe, Au, and Pt.

[0013] Furthermore, in the multilayer ceramic electronic component having the above configuration, the dimension of the diffusion region formed at the end of the internal electrode in the direction along the second axis, as seen in a cross section parallel to a plane including the first axis direction and the second axis direction, can be 0.1 nm or more and 37 μm or less.

[0014] In addition, in the multilayer ceramic electronic component having the above configuration, the dimension of the diffusion region formed at the end of the internal electrode in the direction along the third axis direction, as seen in a cross section parallel to a plane including the first axis direction and the third axis direction, can be 0.1 nm or more and 37 μm or less.

[0015] Furthermore, in the multilayer ceramic electronic component having the above configuration, in a cross section parallel to a plane including the first axis direction and the second axis direction, the diffusion region may be formed at an end of the internal electrode in the second axis direction, and the concentration of any one of Pt, Pd, Au, Ag, Cu, Sn, Fe, Zn, and Al may be higher than that at the upper surface and the lower surface of the internal electrode.

[0016] Furthermore, in the multilayer ceramic electronic component having the above configuration, in a cross section parallel to a plane including the first axis direction and the third axis direction, the diffusion region may be formed at an end of the internal electrode in the third axis direction, and the concentration of any one of Pt, Pd, Au, Ag, Cu, Sn, Fe, Zn, and Al may be higher at the upper surface and the lower surface of the internal electrode than at the lower surface.

[0017] In the multilayer ceramic electronic component having the above configuration, the multilayer ceramic electronic component may have outer dimensions such that the dimensions along the first axis direction and the second axis direction are each 2.8 mm or less, and the dimension along the third axis direction is 6.1 mm or less.

[0018] In the multilayer ceramic electronic component having the above configuration, the main component of the internal electrodes may be Ni, and Ni may be present in the diffusion regions.

[0019] In addition, in the multilayer ceramic electronic component having the above configuration, the dimension of the diffusion region formed at the end of the internal electrode in the direction along the third axis, as seen in a cross section parallel to a plane including the first axis direction and the third axis direction, can be 0.1 nm or more and 3.5 nm or less.

[0020] Furthermore, in the multilayer ceramic electronic component having the above configuration, the dimension of the diffusion region formed at the end of the internal electrode in the direction along the third axis direction, as seen in a cross section parallel to a plane including the first axis direction and the third axis direction, can be 0.8 μm or more and 18 μm or less.

[0021] The method for manufacturing a multilayer ceramic electronic component disclosed in this specification can include the following aspects: a first step of arranging a first pattern of a metal conductive paste on a green sheet containing main component ceramic particles; a second step of arranging a second pattern on the green sheet in a peripheral region of the metal conductive paste, the second pattern including at least one metal selected from Pt, Pd, Au, Ag, Cu, Sn, Fe, Zn, and Al, or an oxide of these metals, together with the main component ceramic particles; a third step of stacking a plurality of the multilayer units obtained in the second step to obtain a ceramic laminate, and firing the resulting ceramic laminate; and a fourth step of plating the ceramic laminate obtained in the third step to form external electrodes.

[0022] According to the invention disclosed in this specification, it is possible to provide a multilayer ceramic electronic component that can suppress deterioration of reliability such as current leakage even when hydrogen penetrates into the component.

[0023] FIG. 1 is a perspective view of a multilayer ceramic capacitor according to an embodiment. FIG. 2(A) is a cross-sectional view taken along line A-A in FIG. 1. FIG. 2(B) is an enlarged view of an end of a first internal electrode. FIG. 2(C) is an enlarged view of an end of a second internal electrode. FIG. 3 is a cross-sectional view taken along line B-B in FIG. 1. FIG. 4(A) is a cross-sectional view taken along line C-C in FIG. 1, and FIG. 4(B) is an enlarged view of an end of an internal electrode. FIG. 5 is a flowchart showing an example of a manufacturing method for a multilayer ceramic capacitor according to an embodiment. FIGS. 6(A) and 6(B) are perspective views showing some of the steps included in a manufacturing method for a multilayer ceramic capacitor. FIGS. 7(A) to 7(C) are explanatory views showing some of the steps included in another manufacturing method for a multilayer ceramic capacitor.

[0024] Ceramic electronic components according to embodiments of the present invention will be described below with reference to the accompanying drawings. The dimensions, ratios, and so forth of the various parts in the drawings may not be exactly the same as those in reality. For convenience of illustration, some details or components may be omitted in some drawings. The drawings appropriately show mutually orthogonal X-, Y-, and Z-axes. In the following description, the Z-axis direction corresponds to the first axis direction, the Y-axis direction corresponds to the second axis direction, and the X-axis direction corresponds to the third axis direction.

[0025] (Embodiment) [Structure of Multilayer Ceramic Capacitor] First, with reference to FIGS. 1 to 4B, a multilayer ceramic capacitor (MLCC) 1 according to an embodiment will be described. FIG. 1 is a perspective view of the multilayer ceramic capacitor 1 according to the embodiment. FIG. 2A is a cross-sectional view taken along line A-A in FIG. 1. FIG. 2B is an enlarged view of an end of a first internal electrode 25. FIG. 2C is an enlarged view of an end of a second internal electrode 26. FIG. 3 is a cross-sectional view taken along line B-B in FIG. 1. FIG. 4A is a cross-sectional view taken along line C-C in FIG. 1, and FIG. 4B is an enlarged view of the ends of the internal electrodes 25, 26. In the multilayer ceramic capacitor 1, the X-axis direction is the length direction, the Y-axis direction is the width direction, and the Z-axis direction is the height direction.

[0026] The multilayer ceramic capacitor 1 includes a ceramic body 2, a first external electrode 3A provided at one end in the longitudinal direction of the multilayer ceramic capacitor 1, and a second external electrode 3B provided at the other end.

[0027] The ceramic body 2 is configured as a hexahedron having first and second main surfaces MF1, MF2 orthogonal to the Z-axis direction, first and second end faces EF1, EF2 orthogonal to the X-axis direction, and first and second side surfaces SF1, SF2 orthogonal to the Y-axis direction. Note that the term "hexahedron" refers to any shape that is substantially hexahedral, and for example, the edges connecting the faces of the ceramic body 2 may be rounded.

[0028] The main surfaces MF1 and MF2, end surfaces EF1 and EF2, and side surfaces SF1 and SF2 of the ceramic body 2 are all flat surfaces. The flat surfaces according to this embodiment do not necessarily have to be strictly planar as long as they are recognized as flat when viewed overall, and include, for example, surfaces with minute irregularities or gently curved shapes within a predetermined range.

[0029] The ceramic body 2 has a laminated portion 21 and a pair of side margin portions 22. The laminated portion 21 has a capacitance forming portion 23 and a pair of cover layers 24. The capacitance forming portion 23 includes a plurality of first internal electrodes 25 and second internal electrodes 26 that are alternately laminated with a plurality of dielectric layers 27 along the Z-axis direction. In this embodiment, the first internal electrodes 25, the second internal electrodes 26, and the dielectric layers 27 are each configured in a sheet shape extending along the XY plane. Note that the number of layers of the first and second internal electrodes 25, 26 in each drawing does not represent the actual number of layers.

[0030] The first and second internal electrodes 25, 26 are alternately arranged along the Z-axis direction (height direction) so as to face each other in the Z-axis direction. The first and second internal electrodes 25, 26 face each other in the Z-axis direction in a facing region at the center of the X-axis and Y-axis directions. The first internal electrode 25 passes through the end margin 28 from the facing region to one end face EF1 and is connected to the first external electrode 3A. The second internal electrode 26 passes through the end margin 28 from the facing region to the other end face EF2 and is connected to the second external electrode 3B.

[0031] The first internal electrode 25 and the second internal electrode 26 can be formed from a metal containing Ni (nickel), Cu (copper), Pd, Pt, Ag, or an alloy thereof as a main component.

[0032] In a plan view from the Z-axis direction, the first internal electrode 25 and the second internal electrode 26 have diffusion regions 29 on their outer peripheries containing a metal different from the main component of these internal electrodes. The diffusion regions 29 are formed in the areas in contact with the dielectric layers. The diffusion regions 29 can suppress deterioration in reliability due to hydrogen penetration from the external electrodes 3A, 3B. In other words, they can suppress current leakage between the electrodes. As will be described later, the external electrodes 3A, 3B are formed by plating on a base electrode layer. During the plating process, there is a concern that the internal electrodes may absorb hydrogen. If hydrogen is absorbed by the internal electrodes, the insulation resistance of the multilayer ceramic capacitor may deteriorate. The diffusion regions 29 can suppress deterioration of the insulation resistance of such components.

[0033] The elements contained in the diffusion region 29 can be at least one selected from the main components of the internal electrode, as well as platinum (Pt), palladium (Pd), gold (Au), silver (Ag), copper (Cu), tin (Sn), iron (Fe), zinc (Zn), and aluminum (Al).

[0034] The diffusion region 29 is provided in the cross section shown in FIG. 2A , i.e., at the end of the first internal electrode 25 and the end of the second internal electrode 26 that appear in the X-Z plane. The diffusion region 29 is also provided in the cross section shown in FIG. 4A , i.e., at the end of the first internal electrode 25 and the end of the second internal electrode 26 that appear in the Y-Z plane. In this embodiment, the diffusion region 29 is provided over the entire periphery of the second internal electrode 26, as in the case of the second internal electrode 26 shown in FIG. 3 . While only the second internal electrode 26 is shown in FIG. 3 , the diffusion region 29 is also provided over the entire periphery of the first internal electrode 25. However, it is sufficient that the diffusion region 29 is provided over at least a portion of the periphery of the first internal electrode 25 or the second internal electrode 26.

[0035] 2(B), the diffusion region 29 covers the end face 25d of the first internal electrode 25, but does not extend to the upper face 25a or the lower face 25b of the first internal electrode 25. Similarly, with reference to Fig. 2(C), the diffusion region 29 covers the end face 26d of the second internal electrode 26, but does not extend to the upper face 26a or the lower face 26b of the second internal electrode 26. In other words, the diffusion region 29 is formed at the end of the internal electrode in the third axis direction (X-axis direction), and the concentration of any one of elements Pt, Pd, Au, Ag, Cu, Sn, Fe, Zn, and Al is higher in the end region than in the upper and lower faces of the internal electrode.

[0036] 4B, the diffusion region 29 covers the side surface 25c of the first internal electrode 25, but does not extend to the upper surface 25a or the lower surface 25b of the first internal electrode 25. This is also true for the diffusion region 29 formed in the second internal electrode 26.

[0037] In other words, the diffusion region 29 is formed so as not to protrude beyond the upper surface 25 a and the lower surface 25 b of the first internal electrode 25 or the upper surface 26 a and the lower surface 26 b of the second internal electrode 26. By forming the diffusion region 29 on at least a part of the end surface or side surface of the internal electrode, deterioration of insulation resistance can be suppressed more efficiently with a small amount of diffusion region 29. Note that the diffusion region 29 may also be formed so as to extend over the upper surface 25 a and the lower surface 25 b of the first internal electrode 25 and the upper surface 26 a and the lower surface 26 b of the second internal electrode 26.

[0038] By providing the diffusion regions 29 at the ends of the first internal electrode 25 and the second internal electrode 26 in this manner, it is possible to effectively suppress hydrogen absorption.

[0039] As shown in FIG. 2B, the dimension L

[29] of the diffusion region 29 along the X-axis direction can be 0.1 nm or more and 37 μm or less. Similarly, as shown in FIG. 4B, the dimension W

[29] of the diffusion region 29 along the Y-axis direction can be 0.1 nm or more and 37 μm or less. Here, the dimensions L

[29] and W

[29] are expressed as the distance from a position close to the center of the internal electrode to the outermost portion of the diffusion region 29 in an arbitrary cross section such as that shown in FIG. 2B or 4B. The dimensions L

[29] and W

[29] can more preferably be 0.1 nm or more and 3.5 nm or less, or 0.8 μm or more and 18 μm or less. The upper limit of the dimension L

[29] is set to 37 μm because, if it exceeds 37 μm, the ESR becomes high. Therefore, it is preferable to set it to 37 μm or less.

[0040] With this configuration, when a voltage is applied between the external electrodes 3A and 3B in the multilayer ceramic capacitor 1, the voltage is applied to the plurality of dielectric layers 27 between the internal electrodes 25 and 26 in the opposing region, causing the multilayer ceramic capacitor 1 to store electric charge according to the voltage between the external electrodes 3A and 3B.

[0041] In the laminated portion 21, a dielectric ceramic having a high dielectric constant is used to increase the capacitance of each dielectric layer 27 between the first and second internal electrodes 25, 26. An example of a dielectric ceramic having a high dielectric constant is barium titanate (BaTiO ３ Examples of suitable perovskite materials include materials with a perovskite structure containing barium (Ba) and titanium (Ti), such as ZnO, ZnO, and ZnO.

[0042] The dielectric ceramic is strontium titanate (SrTiO ３ ), calcium titanate (CaTiO ３ ), magnesium titanate (MgTiO ３ ), calcium zirconate (CaZrO ３ ), calcium zirconate titanate (Ca(Zr,Ti)O ３ ), barium calcium zirconate titanate ((Ba,Ca)(Zr,Ti)O ３ ), barium zirconate (BaZrO３ ), titanium oxide (TiO ２ Here, instead of adding a low-melting point metal to the first and second internal electrodes 25, 26, or in addition to adding a low-melting point metal to the first and second internal electrodes 25, 26, a low-melting point metal may be added to the dielectric ceramic.

[0043] The pair of cover layers 24 cover the capacitance forming portion 23 from both sides in the Z-axis direction, which is the stacking direction. The cover layer 24 is sometimes referred to as a protective layer in the height direction. The cover layer 24 is formed, for example, by a laminate of ceramic sheets extending along the XY plane. From the viewpoint of suppressing internal stress, the dielectric ceramic forming the cover layer 24 preferably has the same composition as the dielectric layer 27.

[0044] The pair of side margins 22 are formed along the Z-axis direction and cover the laminated portion 21 from the Y-axis direction. The side margins 22 are sometimes referred to as widthwise protective layers. The side margins 22 are formed on surfaces of the laminated portion 21 that are perpendicular to the Y-axis direction. The dielectric ceramic that constitutes the side margins 22 preferably has the same composition as the dielectric layer 27 from the viewpoint of suppressing internal stress, etc.

[0045] The multilayer ceramic capacitor 1 includes a first external electrode 3A provided at one end in the length direction (X-axis direction) of the multilayer ceramic capacitor 1, and a second external electrode 3B provided at the other end.

[0046] In the external electrodes 3A, 3B, both the cross section parallel to the XZ plane and the cross section parallel to the XY plane are U-shaped. The shapes of the external electrodes 3A, 3B are not limited to the examples shown in the drawings.

[0047] The size of the multilayer ceramic capacitor 1 is not particularly limited, but can be selected from the following design values: length 0.25 mm, width 0.125 mm, height 0.125 mm (0201 size), length 0.4 mm, width 0.2 mm, height 0.2 mm (0402 size), length 0.6 mm, width 0.3 mm, height 0.3 mm (0603 size), length 1.0 mm, width 0.5 mm, height 0.5 mm (1005 size), length 3.2 mm, width 1.6 mm, height 1.6 mm (3216 size), length 4.5 mm, width 3.2 mm, height 2.5 mm (4532 size), or length 5.7 mm, width 5.0 mm, height 2.3 mm (5750 size). It can also be smaller than the 0402 size, i.e., it can have any of the length, width, and height smaller than the 0402 size. Furthermore, taking into account general manufacturing variations, the width and height may each be 2.8 mm or less, and the length may be 6.1 mm or less. In such a small multilayer ceramic capacitor, measures to prevent current leakage between the electrodes are essential, but the multilayer ceramic capacitor 1 of this embodiment is provided with the diffusion region 29, and therefore can suppress the occurrence of current leakage between the electrodes even when miniaturized.

[0048] [Manufacturing Method] Next, an example of a method for manufacturing the multilayer ceramic capacitor 1 will be described with reference to Fig. 5 to Fig. 7. Fig. 5 is a flowchart showing an example of a method for manufacturing the multilayer ceramic capacitor 1 according to the embodiment. Figs. 6(A) and 6(B) are perspective views showing some of the steps included in the method for manufacturing the multilayer ceramic capacitor. Figs. 7(A) to 7(C) are explanatory views showing some of the steps included in another method for manufacturing the multilayer ceramic capacitor 1.

[0049] (Raw Powder Preparation Step) In the raw powder preparation step of step S1, first, a dielectric material for forming the dielectric layer 27 is prepared. The A-site elements and B-site elements contained in the dielectric layer 27 are usually ABO ３ The dielectric layer 27 contains a sintered body of BaTiO particles. ３is a tetragonal compound with a perovskite structure and exhibits a high dielectric constant. ３ Generally, it can be obtained by synthesizing barium titanate by reacting a titanium raw material such as titanium dioxide with a barium raw material such as barium carbonate. Various methods have been known for synthesizing the ceramic that constitutes the dielectric layer 27, such as a solid-phase method, a sol-gel method, and a hydrothermal method. Any of these methods can be used in this embodiment.

[0050] To the obtained barium titanate ceramic powder, predetermined additives are added depending on the purpose. Examples of additives include rare earth elements such as dysprosium (Dy) and holmium (Ho), magnesium (Mg), vanadium (V), silicon (Si), and manganese (Mn). These additives are, for example, in the form of oxides of the respective elements, such as Ho. ２ O ３ , MgO, V ２ O ５ , SiO ２ , Mn ３ O ４ These additives may be added in the process of synthesizing barium titanate.

[0051] In this embodiment, first, a compound containing an additive compound is mixed with powders of titanium dioxide and barium carbonate as raw materials for barium titanate, which is the main component constituting the dielectric layer 27, and the mixture is calcined at 820 to 1150°C. Next, the resulting ceramic particles are wet-mixed with the additive compound, dried, and pulverized to prepare a ceramic powder. For example, from the viewpoint of thinning the dielectric layer 27, the average particle size of the ceramic powder is preferably 50 to 300 nm. For example, the ceramic powder obtained as described above may be pulverized as necessary to adjust the particle size, or may be regulated by combining it with a classification process.

[0052] Next, a thickness compensation material is prepared for forming the side margin portion 22 and the end margin portion 28. The thickness compensation material can be obtained by adding a predetermined additive to a ceramic powder whose main component is barium titanate, which is obtained by a process similar to the process for producing the dielectric material described above. The predetermined additive can be at least one metal selected from Pt, Pd, Au, Ag, Cu, Sn, Fe, Zn, and Al, or an oxide of these metals. These metals and oxides of these metals diffuse into the outer periphery of the internal electrode during the firing process described below, forming a diffusion region 29.

[0053] The amount of these predetermined additives is, for example, in the range of 0.01 wt% to 3.0 wt%, assuming that the Ti content of barium titanate is 100%. If the amount of the predetermined additive is less than 0.01 wt%, assuming that the Ti content of barium titanate is 100%, it will not be enough to diffuse to the outer periphery of the internal electrode. Furthermore, if it is more than 3.0 wt%, the composition amount will deviate from the main component dielectric material, making cracks more likely to occur. The range of the amount of the predetermined additive can be determined taking these factors into consideration.

[0054] For example, the average particle size of the thickness compensation material is preferably 50 to 300 nm, in accordance with the dielectric material. For example, the ceramic powder obtained as described above may be subjected to a pulverization process as necessary to adjust the particle size, or may be combined with a classification process to adjust the particle size.

[0055] Next, a binder such as polyvinyl butyral (PVB) resin, an organic solvent such as ethanol or toluene, and a plasticizer such as triethylene glycol are added to the obtained dielectric material and wet mixed. The obtained slurry is used to coat a strip-shaped dielectric green sheet 51 (see FIG. 6A) having a thickness of, for example, 0.8 μm or less on a substrate by, for example, a die coater method or a doctor blade method, and then dried.

[0056] Next, a metal conductive paste containing an organic binder for forming internal electrodes is printed on the surface of the dielectric green sheet 51 by screen printing, gravure printing, or the like, to form an internal electrode pattern 52 (see FIG. 6A) that alternately leads to a pair of external electrodes of opposite polarity. Ceramic particles may be added to the metal conductive paste as a co-material. The main component of the ceramic particles as the co-material is not particularly limited, but is preferably the same as the main ceramic component of the dielectric layer 27.

[0057] Next, a binder such as an ethyl cellulose-based binder and an organic solvent such as a terpineol-based binder are added to the thickness compensation material, and the mixture is kneaded in a roll mill to obtain a thickness compensation paste. The thickness compensation paste is printed on the dielectric green sheet 51 in the peripheral area where the internal electrode pattern 52 is not printed, thereby arranging the thickness compensation portion 53 (see FIG. 6A ) and filling in the step with the internal electrode pattern 52.

[0058] Thereafter, a predetermined number of layers (for example, 100 to 500 layers) are laminated so that the internal electrode layers 12 and the dielectric layers 11 are alternately arranged, and so that the edges of the internal electrode layers 12 are alternately exposed on both longitudinal end faces of the dielectric layers 11 and are alternately drawn out to a pair of external electrodes 3A, 3B having different polarities and are electrically connected.

[0059] A laminate is formed by pressing cover sheets that will become cover layers 24 onto the top and bottom of the laminated dielectric green sheets 51. To make the explanation easier to understand, the laminate has been described as being cut into individual laminate units, but it can also be manufactured using a known method in which multiple pieces are laminated and then cut into individual pieces. Then, a metal conductive paste that will become the base layers for the external electrodes 3A, 3B is applied to both sides of the laminate by a dipping method or the like and dried. This produces a molded multilayer ceramic capacitor 1.

[0060] (Firing step) The molded body thus obtained is fired in a N ２After the binder is removed in the atmosphere, the material is fired at 1100 to 1300°C for 10 minutes to 2 hours in a reducing atmosphere with an oxygen partial pressure of 10-5 to 10-8 atm, causing each compound to sinter and grow into grains. At this time, metals such as Pt, Pd, Cu, Sn, Fe, Zn, and Al added to the thickness compensation material and oxides of these metals diffuse toward the outer periphery of the internal electrodes 25 and 26, forming a diffusion region 29.

[0061] The firing conditions can be set as appropriate to form the diffusion region 29. That is, the conditions can be adjusted so that the metal component added to the thickness compensation material is diffused and present in the outer periphery of the internal electrodes 25, 26 during the firing process. The metal component or metal oxide can be more easily diffused into the outer periphery of the internal electrodes 25, 26 by increasing the amount of metal or metal oxide added, raising the firing temperature, or extending the firing time.

[0062] (Reoxidation treatment step) Then, N ２ A reoxidation treatment may be carried out in a gas atmosphere at 600° C. to 1000° C.

[0063] (Plating Process) Subsequently, plating is performed on the base layer of the external electrode to form a plating layer. If the base layer is made of nickel, it is preferable to form a copper plating layer, a nickel plating layer, and a tin plating layer. If the base layer is made of copper, it is preferable to form a nickel plating layer and a tin plating layer. This results in the formation of external electrodes 3A, 3B composed of the base layer and plating layer. At this time, there is a concern about hydrogen absorption in the internal electrodes 25, 26. However, according to this embodiment, since the diffusion region 29 is formed on the outer periphery of the internal electrodes 25, 26, hydrogen absorption in the internal electrodes 25, 26 is suppressed. The base layer of the external electrode may also be formed by applying an electrode paste for the external electrode after the firing process and sintering it.

[0064] <Modification> Here, another manufacturing method will be described with reference to FIGS. 7A to 7C. In the above manufacturing method, an additive for forming the diffusion region 29 is added to the thickness compensation material forming the thickness compensation portion 53 shown in FIGS. 6A and 6B. In contrast, in this modification, a dielectric green sheet 61 is prepared (see FIG. 7A), and an additional printed portion 63 is provided around an internal electrode pattern 62 (see FIG. 7B) arranged on the dielectric green sheet 61 (see FIG. 7C). In this modification, the additional printed portion 63 is formed from a material containing at least one metal selected from the group consisting of Pt, Pd, Au, Ag, Cu, Sn, Fe, Zn, and Al, or a material composition containing oxides of these metals as its main component. A thickness compensation portion 64 is provided around the additional printed portion 63 to compensate for the step between the internal electrode pattern 62 and the additional printed portion 63. The thickness compensation portion 64 does not contain the element that is the main component of the additional printed portion 63, and is formed mainly from ceramic powder of barium titanate.

[0065] The elements present in the diffusion region mentioned above each have the following characteristics. Pt and Au are resistant to oxidation and therefore tend to remain as metals, reducing the ESR of the component and improving the continuity of the internal electrodes. Furthermore, Pd, Ag, and Cu easily absorb hydrogen, so they more effectively suppress the deterioration of insulation resistance. Sn, Fe, Zn, and Al are effective in improving the continuity of the internal electrodes.

[0066] [Effects] The multilayer ceramic capacitor 1 of this embodiment has a diffusion region 29 containing a metal different from the main component of the internal electrodes 25, 26 at the outer periphery of the internal electrodes 25, 26. This makes it possible to suppress deterioration of the insulation resistance value due to penetration of hydrogen from the external electrodes 3A, 3B into the internal electrodes 25, 26. It also makes it possible to suppress the occurrence of current leakage between the electrodes.

[0067] Next, examples will be described in comparison with comparative examples. Examples 1 to 17 were prepared as samples embodying the present embodiment, and comparative examples 1 and 2 were also prepared. Each example and comparative example had 1,000 samples. The IR defect rate, i.e., the frequency of IR degradation (deterioration of insulation resistance) per 1,000 samples, was then measured for each example and comparative example. Each sample was subjected to a withstand voltage test in which 10 V was applied for 100 hours at a temperature of 85°C and a relative humidity of 85%. The number of samples that exhibited a resistance of 100 MΩ or less for 60 seconds was then counted, and this number was expressed as the number of IR defects per 1,000 samples. Examples 1 to 8 and 12 to 17 were manufactured using the manufacturing method shown in FIGS. 6A and 6B , i.e., a method in which an additive for forming a diffusion region 29 was added to the thickness compensation portion 53. In contrast, Examples 9 and 10 were manufactured by the manufacturing method shown in Figures 7(A) to 7(C), that is, a method in which an additive was added to form the diffusion region 29 by printing the additional printed portion 63. The internal electrodes of each Example were mainly composed of nickel. A predetermined additive metal was confirmed in the diffusion region 29. Nickel, a component of the internal electrode, was also confirmed in the diffusion region 29.

[0068] The size of the samples of Examples 1 to 11 and Comparative Example 1 shown in Table 1 was 0.4 mm x 0.2 mm x 0.2 mm, where L[1] is the length, W[1] is the width, and H[1] is the height of the multilayer ceramic capacitor 1 shown in Figure 1. The dimensions of the internal electrodes 25, 26 were 0.3 μm x 0.1 μm, where L

[25] (L(26)) is the width, W

[25] is the height, and W(26) is the width shown in Figure 2(A) and Figure 4(A).

[0069] The size of the samples of Examples 12 to 17 and Comparative Example 2 shown in Table 2 was 0.25 mm x 0.125 mm x 0.125 mm, which was the length L[1] x width W[1] x height H[1] of the multilayer ceramic capacitor 1 shown in Figure 1. The dimensions of the internal electrodes 25, 26 were 0.16 mm x 0.07 mm, which was L

[25] (L(26)) x W

[25] (W(26)) shown in Figures 2(A) and 4(A).

[0070] The metal elements forming the diffusion region 29 in Examples 1 to 11 are as shown in Table 1. Comparative Example 1 does not have a diffusion region. The metal elements forming the diffusion region 29 in Examples 12 to 17 are as shown in Table 2. Comparative Example 2 does not have a diffusion region.

[0071] The metal elements contained in the diffusion region 29 other than the composition of the internal electrodes are listed below. The metal element in the first example is Au. The metal element in the second example is Fe. The metal element in the third example is Sn. The metal element in the fourth example is Pt. The metal elements in the fifth example are Au and Fe. The metal elements in the sixth example are Sn and Fe. The metal element in the seventh example is Cu. The metal element in the eighth example is Pd. The metal element in the ninth example is Au. The metal element in the tenth example is Sn. The metal elements in the eleventh example are Au and Fe. The metal element in the twelfth example is Au. The metal element in the thirteenth example is Fe. The metal element in the fourteenth example is Sn. The metal element in the fifteenth example is Pt. The metal elements in the sixteenth example are Au and Fe. The metal elements in the seventeenth embodiment are Sn and Fe.

[0072] The ranges and average values ​​of the diffusion region dimensions L

[29] (see FIG. 2(B)) and W

[29] (see FIG. 4(B)) in Examples 1 to 11 are as shown in Table 1. The ranges (minimum to maximum) and average values ​​of the diffusion region dimensions L

[29] (see FIG. 2(B)) and W

[29] (see FIG. 4(B)) in Examples 12 to 17 are as shown in Table 1. Measurements of the dimensions L

[29] and W

[29] were performed by selecting five samples from 1,000 samples and measuring them at 10 arbitrary locations on the cross section shown in FIG. 2(A) or the cross section shown in FIG. 4(A). The minimum and maximum values ​​of the diffusion region dimensions L

[29] and W

[29] are the minimum and maximum values ​​among the values ​​measured in this manner. The average values ​​of the diffusion region dimensions L

[29] and W

[29] are calculated by averaging the values ​​measured in this manner. Since there was no difference in the average value, maximum value, or minimum value between the dimension L

[29] and the dimension W

[29] , the calculation of the average value, maximum value, and minimum value was performed without distinguishing between the two.

[0073] The size ranges and average values ​​of the diffusion regions in each example are listed below. The size range of the first example is 0.1 nm to 1.8 nm, with an average value of 1.2 nm. The size range of the second example is 0.1 nm to 1.9 nm, with an average value of 1.3 nm. The size range of the third example is 0.2 nm to 2.0 nm, with an average value of 1.6 nm. The size range of the fourth example is 0.1 nm to 3.1 nm, with an average value of 2.5 nm. The size range of the fifth example is 0.1 nm to 2.7 nm, with an average value of 1.9 nm. The size range of the sixth example is 0.1 nm to 3.3 nm, with an average value of 2.2 nm. The size range of the seventh example is 0.1 nm to 1.9 nm, with an average value of 1.4 nm. The size range of the eighth example is 0.1 nm to 1.9 nm, with an average value of 1.3 nm. The dimensional range of the ninth embodiment is 1 μm to 13 μm, with an average value of 9.0 μm. The dimensional range of the tenth embodiment is 0.8 μm to 18 μm, with an average value of 11.7 μm. The dimensional range of the eleventh embodiment is 1.1 μm to 16 μm, with an average value of 10.9 μm. The dimensional range of the twelfth embodiment is 0.1 to 2.0 nm, with an average value of 1.3 nm. The dimensional range of the thirteenth embodiment is 0.1 to 2.2 nm, with an average value of 1.3 nm. The dimensional range of the fourteenth embodiment is 0.2 to 2.2 nm, with an average value of 1.7 nm. The dimensional range of the fifteenth embodiment is 0.1 to 3.0 nm, with an average value of 2.1 nm. The dimensional range of the sixteenth embodiment is 0.1 to 2.7 nm, with an average value of 1.9 nm. The dimensional range of the seventeenth embodiment is 0.1 to 3.5 nm, with an average value of 2.4 nm.

[0074] As a result of the tests carried out in this manner, no IR defects occurred in any of Examples 1 to 17. In contrast, in Comparative Example 1, IR defects were observed in three out of 1,000 samples, and in Comparative Example 2, IR defects were observed in seven out of 1,000 samples.

[0075] From the above results, it was confirmed that the diffusion region 29 suppresses IR defects regardless of the type of metal added and regardless of the manufacturing method.

[0076]

[0077]

[0078] Although the above embodiments have been described with reference to a multilayer ceramic capacitor as an example of a multilayer ceramic electronic component, the present invention is not limited thereto. For example, the configurations of the above embodiments can be applied to other multilayer ceramic electronic components such as varistors and thermistors.

[0079] The above-described embodiments are merely examples for implementing the present invention, and the present invention is not limited to these. Various modifications of these embodiments are within the scope of the present invention. Furthermore, it is obvious from the above description that various other embodiments are possible within the scope of the present invention.

[0080] 1...multilayer ceramic capacitor, 2...ceramic body, 3A...first external electrode, 3B...second external electrode, 25...first internal electrode, 25a, 26a...upper surface, 25b, 26b...lower surface, 25c, 26c...side surface, 25d, 26d...end surface, 26...second internal electrode, 27...dielectric layer, 29...diffusion region, MF1...first main surface, MF2...second main surface, EF1...first end surface, EF2...second end surface, SF1...first side surface, SF2...second side surface.

Claims

1. a ceramic body in which dielectric layers and internal electrodes are alternately stacked along a first axis direction, the ceramic body having a pair of main surfaces opposing each other along the first axis direction, a pair of side surfaces opposing each other in a second axis direction perpendicular to the first axis direction, and a pair of end faces opposing each other in a third axis direction perpendicular to the first axis direction and the second axis direction; a pair of external electrodes provided at respective ends of the ceramic body in the third axis direction, the external electrodes being electrically connected to the internal electrodes respectively drawn out to different ends of the ceramic body in the third axis direction; a metal-containing portion provided in contact with an outer periphery of the internal electrode as viewed from the first axis direction, the metal-containing portion being formed of a material containing, as a main component, a metal different from a main component of the internal electrode; a peripheral dielectric portion provided between the dielectric layers arranged on the upper surface side and the lower surface side of the internal electrode along the first axis direction, the peripheral dielectric portion being provided in contact with a peripheral portion of the metal-containing portion that does not contact the internal electrode as viewed from the first axis direction, and made of a material having a different composition from that of the metal-containing portion; Equipped with the internal electrode has a diffusion region containing a metal different from a main component of the internal electrode in at least a part of an outer periphery thereof, the diffusion region is formed at an end of the internal electrode in the second axis direction in a cross section parallel to a plane including the first axis direction and the second axis direction, or at an end of the internal electrode in the third axis direction in a cross section parallel to a plane including the first axis direction and the third axis direction, and a concentration of any one of Pt, Pd, Au, Ag, Cu, Sn, Fe, Zn, and Al in the diffusion region is higher than that in the upper surface and the lower surface of the internal electrode; Multilayer ceramic electronic components.

2. When the diffusion region is formed at the end of the internal electrode in the second axis direction in a cross section parallel to a plane including the first axis direction and the second axis direction, the dimension of the diffusion region in the second axis direction is 0.1 nm or more and 37 μm or less. The multilayer ceramic electronic component according to claim 1 .

3. When the diffusion region is formed at the end of the internal electrode in the second axis direction in a cross section parallel to a plane including the first axis direction and the third axis direction, the dimension of the diffusion region in the direction along the third axis direction is 0.1 nm or more and 37 μm or less. The multilayer ceramic electronic component according to claim 1 .

4. The laminated ceramic electronic component has outer dimensions of 2.8 mm or less in the first axis direction and the second axis direction, and 6.1 mm or less in the third axis direction. The multilayer ceramic electronic component according to claim 1 .

5. The main component of the internal electrode is Ni, and Ni is present in the diffusion region. The multilayer ceramic electronic component according to claim 1 .

6. When the diffusion region is formed at the end of the internal electrode in the second axis direction in a cross section parallel to a plane including the first axis direction and the third axis direction, the dimension of the diffusion region in the direction along the third axis direction is 0.1 nm or more and 3.5 nm or less. The multilayer ceramic electronic component according to claim 1 .

7. When the diffusion region is formed at the end of the internal electrode in the second axis direction in a cross section parallel to a plane including the first axis direction and the third axis direction, the dimension of the diffusion region in the direction along the third axis direction is 0.8 μm or more and 18 μm or less. The multilayer ceramic electronic component according to claim 1 .

8. A first step of arranging an internal electrode pattern of a metal conductive paste on a green sheet containing ceramic particles as a main component; a second step of forming a metal-containing portion containing at least one metal selected from Pt, Pd, Au, Ag, Cu, Sn, Fe, Zn, and Al, or an oxide of any of these metals, together with the main component ceramic particles, as an additional printed portion in a peripheral region of the metal conductive paste on the green sheet, and providing a peripheral dielectric portion as a thickness compensating portion around the additional printed portion, not in contact with the internal electrodes, for compensating for a step between the internal electrode pattern and the additional printed portion; a third step of stacking a plurality of the lamination units obtained in the second step and firing the resulting ceramic laminate; a fourth step of plating the ceramic laminate obtained in the third step to form external electrodes; Contains Manufacturing method for multilayer ceramic electronic components.