Multilayer ceramic electronic component and method for manufacturing the same

Abstract

To provide a multilayer ceramic electronic component capable of suppressing poor connection between internal electrodes and external electrodes while suppressing poor insulation, and provide a method for manufacturing the same.SOLUTION: The multilayer ceramic electronic component includes a ceramic main body and an external electrode. The ceramic main body includes: a first end surface and a second end surface respectively facing in a first direction; a functional part in which first internal electrodes and second internal electrodes are mutually laminated in a second direction perpendicular to the first direction with ceramic layers interposed therebetween; end margin parts provided respectively between the first end surface and the second internal electrodes and between the second end surface and the first internal electrodes; and side margin parts that respectively cover the functional part from a third direction perpendicular to the first and second directions. The end margin parts contain boron. The side margin parts contain silicon and boron, and a concentration of the boron contained in the side margin parts is less than that of the boron contained in the end margin parts.SELECTED DRAWING: Figure 9

Description

[Technical field]

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

[0002] A typical example of a multilayer ceramic electronic component is a multilayer ceramic capacitor. In recent years, as electronic devices become smaller and have higher performance, there has been an increasing demand for multilayer ceramic capacitors that are smaller and have higher capacitance.

[0003] A multilayer ceramic capacitor typically includes a functional section (capacitance forming section) in which internal electrodes and ceramic layers are alternately laminated, a margin section made of a ceramic material around the functional section, and an external electrode connected to the internal electrode. The margin section includes, for example, an end margin section formed between the internal electrode and the external electrode, and a side margin section covering the side end of the internal electrode. These margins are made of ceramic material and therefore exhibit a different sintering behavior from that of the metal internal electrodes. Specifically, the margins have a higher sintering temperature and sintering proceeds more slowly than metals. Therefore, during firing, stress due to the difference in sintering behavior is applied between the functional parts having the internal electrodes and the margins, making it easier for structural defects such as cracks to occur.

[0004] Therefore, in order to improve the sinterability of the marginal parts, attempts have been made to add sintering aids to the marginal parts. For example, Patent Document 1 describes a multilayer ceramic capacitor having an external dielectric that contains a larger amount of sintering aids, such as manganese or magnesium, than the internal dielectric laminated with the first internal electrode layer and the second internal electrode layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-11172 A Summary of the Invention [Problem to be solved by the invention]

[0006] On the other hand, different sintering properties are required for the end margins and side margins. That is, for the end margins covered by the external electrodes, there is a demand for sintering as quickly as possible, close to the sintering behavior of metals, from the viewpoint of ensuring the connection between the internal electrodes and the external electrodes. For the side margins, it is desirable to approach the sintering behavior of metals from the viewpoint of stress relaxation between the functional parts, but they are easily exposed to the firing atmosphere and are prone to over-sintering. If the side margins are over-sintered, the insulation properties will decrease due to spheroidization and fragmentation of the internal electrodes. For this reason, there is a demand for increasing the sintering property of the side margins while suppressing over-sintering.

[0007] In view of the above circumstances, an object of the present invention is to provide a multilayer ceramic electronic component that is capable of suppressing poor connection between internal electrodes and external electrodes and also suppressing poor insulation, and a method for manufacturing the same. [Means for solving the problem]

[0008] In order to achieve the above object, a multilayer ceramic electronic component according to one aspect of the present invention includes a ceramic body and external electrodes. The ceramic body has a first end face and a second end face each facing in a first direction, a functional section in which a first internal electrode extended to the first end face and a second internal electrode extended to the second end face are stacked on top of each other with a ceramic layer sandwiched between them in a second direction perpendicular to the first direction, end margin sections provided between the first end face and the second internal electrode and between the second end face and the first internal electrode, respectively, and a side margin section covering the functional section from a third direction perpendicular to the first direction and the second direction. The external electrodes are provided on the first end surface and the second end surface, respectively. The end margin is boron (B) 、 and , a concentration higher than that of the boron Contains silicon (Si). The side margin portion has a higher concentration of silicon (Si) than the end margin portion, a concentration lower than that of silicon, and and a lower concentration of boron than the end margin portion.

[0009] The end margins contain a high concentration of boron, which is highly effective in increasing sinterability, and this makes the sintering behavior closer to that of the metallic external and internal electrodes. This makes it easier for the end margins to shrink in accordance with the external and internal electrodes during sintering, thereby making it possible to suppress poor connections between the external and internal electrodes. On the other hand, the side margins are easily exposed to the firing atmosphere, and are prone to oversintering due to boron. For this reason, by making the boron concentration in the side margins lower than that in the end margins, abnormal grain growth of ceramic particles due to oversintering can be suppressed, and short circuits due to spheroidization and fragmentation of the internal electrodes and deterioration of insulation can be suppressed. In addition, by gradually increasing the sinterability of the side margins with silicon, stress caused by differences in sintering behavior between the side margins and the functional parts having the internal electrodes can be suppressed. Therefore, structural defects such as cracks between the side margins and the functional parts can be suppressed, and insulation failures caused by these defects can be suppressed.

[0010] The end margin portion includes silicon (Si), The side margins may have a higher concentration of silicon than the end margins. By containing a high concentration of silicon in the side margin portion, the sinterability of the side margin portion can be controlled by silicon. Therefore, while suppressing over-sintering in the side margin portion, it is possible to suppress stress caused by the difference in sintering behavior between the side margin portion and the functional portion having the internal electrode. Therefore, structural defects such as cracks between the side margin portion and the functional portion can be more reliably suppressed, and insulation failures caused by such defects can be suppressed.

[0011] For example, the end margin portion is mainly composed of a ceramic material having a perovskite structure represented by the general formula ABO3 as a main phase, When the element concentration at the B site of the ceramic material in the end margin portion is taken as 100 atm %, the boron concentration in the end margin portion may be 0.015 atm % or more and 0.025 atm % or less.

[0012] For example, the boron concentration in the side margin portion may be 70% or less of the boron concentration in the end margin portion.

[0013] A method for manufacturing a ceramic electronic component according to another aspect of the present invention includes: a functional section in which a first end face and a second end face each facing a first direction, a first internal electrode drawn to the first end face and a second internal electrode drawn to the second end face are laminated with a ceramic layer therebetween in a second direction perpendicular to the first direction; and boron (B) 、 and , a concentration higher than that of the boron an end margin portion including silicon (Si); and a third direction that covers the functional portion from the first direction and the second direction, the third direction being perpendicular to the first direction and the second direction, and the end margin portion including silicon (Si) having a higher concentration than the end margin portion. a concentration lower than that of silicon, and and a side margin portion that contains a lower concentration of boron than the end margin portion. Unsintered external electrodes are formed on the first end surface and the second end surface, respectively. The green ceramic body on which the green external electrodes are formed is fired. Effect of the Invention

[0014] As described above, according to the present invention, it is possible to provide a multilayer ceramic electronic component that is capable of suppressing connection failures between internal electrodes and external electrodes and also suppressing insulation failures, and a method for manufacturing the same. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view of a multilayer ceramic capacitor in accordance with a first embodiment of the present invention. [Diagram 2] 2 is a perspective view of the multilayer ceramic capacitor taken along line AA' in FIG. [Diagram 3] 2 is a cross-sectional view of the multilayer ceramic capacitor taken along line BB' in FIG. [Figure 4] 4 is a flowchart showing a method for manufacturing the multilayer ceramic capacitor. [Diagram 5] 3A to 3C are plan views illustrating a manufacturing process of the multilayer ceramic capacitor. [Figure 6] 3A to 3C are perspective views illustrating a manufacturing process of the multilayer ceramic capacitor. [Figure 7] 3A to 3C are perspective views illustrating a manufacturing process of the multilayer ceramic capacitor. [Figure 8] 3A to 3C are perspective views illustrating a manufacturing process of the multilayer ceramic capacitor. [Figure 9] 3A to 3C are schematic cross-sectional views showing a manufacturing process of the multilayer ceramic capacitor. [Figure 10] FIG. 3 is a cross-sectional view showing a laser irradiation method by LA-ICP-MS for the multilayer ceramic capacitor according to the first embodiment of the present invention. [Figure 11] 4 is a graph showing boron concentrations in the Y-axis direction of ceramic layers and side margin portions of the multilayer ceramic capacitor. [Figure 12] FIG. 3 is a cross-sectional view showing a laser irradiation method by LA-ICP-MS for the multilayer ceramic capacitor according to the first embodiment of the present invention. [Figure 13] 4 is a graph showing boron concentrations in the X-axis direction of ceramic layers and end margin portions of the multilayer ceramic capacitor. [Figure 14] 5 is a cross-sectional view of a multilayer ceramic capacitor in accordance with a second embodiment of the present invention, taken along a cut surface corresponding to FIG. 2. [Figure 15] 4 is a cross-sectional view of the multilayer ceramic capacitor taken along a cut surface corresponding to FIG. 3. [Figure 16] 4 is a flowchart showing a method for manufacturing the multilayer ceramic capacitor. [Figure 17]3A to 3C are plan views illustrating a manufacturing process of the multilayer ceramic capacitor. [Figure 18] 3A to 3C are perspective views illustrating a manufacturing process of the multilayer ceramic capacitor. [Figure 19] 3A to 3C are schematic cross-sectional views showing a manufacturing process of the multilayer ceramic capacitor. [Figure 20] 5A to 5C are schematic cross-sectional views illustrating a manufacturing process of the multilayer ceramic capacitor in accordance with a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, an X-axis, a Y-axis, and a Z-axis that are mutually orthogonal are shown as appropriate, and the X-axis, the Y-axis, and the Z-axis are common to all the drawings.

[0017] First Embodiment [Configuration of multilayer ceramic capacitor 10] 1 to 3 are diagrams showing a multilayer ceramic capacitor 10 according to a first embodiment of the present invention. Fig. 1 is a perspective view of the multilayer ceramic capacitor 10. Fig. 2 is a cross-sectional view of the multilayer ceramic capacitor 10 taken along line A-A' in Fig. 1. Fig. 3 is a cross-sectional view of the multilayer ceramic capacitor 10 taken along line B-B' in Fig. 1.

[0018] The multilayer ceramic capacitor 10 includes a ceramic body 11, a first external electrode 14, and a second external electrode 15. The ceramic body 11 has a first end face 11a and a second end face 11b facing the X-axis direction, a first side face 11c and a second side face 11d facing the Y-axis direction, and a first main face 11e and a second main face 11f facing the Z-axis direction. Note that ridges connecting the respective faces of the ceramic body 11 may be rounded.

[0019] The first external electrode 14 is provided on the first end face 11a. The second external electrode 15 is provided on the second end face 11b. The first external electrode 14 extends from the first end face 11a of the ceramic body 11 to both main faces 11e, 11f and both side faces 11c, 11d. Similarly, the second external electrode 15 extends from the second end face 11b of the ceramic body 11 to both main faces 11e, 11f and both side faces 11c, 11d. As a result, the cross sections of the external electrodes 14, 15 parallel to the XZ plane and the cross sections parallel to the XY plane are both U-shaped. The shapes of the external electrodes 14, 15 are not limited to those shown in FIG. 1.

[0020] The external electrodes 14, 15 are made of a good electrical conductor. Examples of the good electrical conductor that forms the external electrodes 14, 15 include metals or alloys containing, as a main component, copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), etc.

[0021] The ceramic body 11 has a capacitance forming portion 16, a side margin portion 17, an end margin portion 18, and a cover portion 19. The capacitance forming portion 16 is configured as a functional portion in this embodiment.

[0022] The capacitance forming portion 16 has first internal electrodes 12 and second internal electrodes 13 that are alternately laminated in the Z-axis direction with a plurality of ceramic layers 20 sandwiched therebetween. The internal electrodes 12, 13 are formed of a good electrical conductor. Typical examples of good electrical conductors that form the internal electrodes 12, 13 include nickel (Ni), as well as metals or alloys mainly composed of copper (Cu), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), etc.

[0023] The internal electrodes 12, 13 are each configured in a sheet shape extending along the XY plane. The first internal electrode 12 is drawn out to the first end face 11a and connected to the first external electrode 14. The second internal electrode 13 is drawn out to the second end face 11b and connected to the second external electrode 15. As a result, when a voltage is applied between the first external electrode 14 and the second external electrode 15, the voltage is applied to the ceramic layer 20 between the first internal electrode 12 and the second internal electrode 13, and a charge according to the voltage is stored in the capacitance forming portion 16.

[0024] In the ceramic body 11, a dielectric ceramic with a high dielectric constant is used to increase the capacitance of each ceramic layer 20 between the internal electrodes 12 and 13. Examples of dielectric ceramics with a high dielectric constant include materials with a perovskite structure containing barium (Ba) and titanium (Ti), such as barium titanate (BaTiO3).

[0025] The ceramic layer 20 may be composed of a strontium titanate (SrTiO3)-based, calcium titanate (CaTiO3)-based, magnesium titanate (MgTiO3)-based, calcium zirconate (CaZrO3)-based, calcium zirconate titanate (Ca(Zr,Ti)O3)-based, barium zirconate (BaZrO3)-based, titanium oxide (TiO2)-based, or the like.

[0026] In addition to the above main components, the ceramic layer 20 may contain boron (B) as an auxiliary component. In addition, the ceramic layer 20 may contain silicon (Si), vanadium (V), manganese (Mn), magnesium (Mg), lithium (Li), sodium (Na), potassium (K), rare earth elements (yttrium (Y), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), ytterbium (Yb)), etc. as auxiliary components, and the types are not limited to those mentioned above.

[0027] The end margin portions 18 are provided between the capacitance forming portion 16 and the external electrodes 14, 15. Specifically, the end margin portions 18 are provided between the first end face 11a and the second internal electrode 13, and between the second end face 11b and the first internal electrode 12. The end margin portions 18 are formed of insulating ceramics, and ensure insulation between the first internal electrode 12 and the second external electrode 15, and also ensure insulation between the second internal electrode 13 and the first external electrode 14.

[0028] The cover portions 19 are provided on both sides in the Z-axis direction of the capacitance forming portion 16. The cover portions 19 are formed of insulating ceramics, and ensure insulation of the capacitance forming portion 16 in the Z-axis direction and protect the capacitance forming portion 16. In this embodiment, the capacitance forming portion 16, the end margin portions 18, and the cover portions 19 are configured as a laminated body having a substantially rectangular parallelepiped shape.

[0029] The side margin portion 17 covers the capacitance forming portion 16 from the Y-axis direction. The side margin portion 17 is formed of insulating ceramics, and ensures insulation of the capacitance forming portion 16 in the Y-axis direction and protects the capacitance forming portion 16. The side margin portion 17 of this embodiment is configured to cover the Y-axis direction side surface of the laminate consisting of the capacitance forming portion 16, the end margin portion 18, and the cover portion 19. In this case, the positions of the Y-axis direction end portions of the internal electrodes 12, 13 are aligned with each other within a range of 0.5 μm in the Y-axis direction.

[0030] The insulating ceramics used in the end margin portion 18, the cover portion 19, and the side margin portion 17 may contain the dielectric ceramics used in the ceramic layer 20. More specifically, the side margin portion 17 and the end margin portion 18 have the following composition.

[0031] [Composition of side margin portion 17 and end margin portion 18] The side margin portion 17 and the end margin portion 18 are mainly composed of a ceramic material having a perovskite structure represented by the general formula ABO3 as a main phase. Examples of such ceramic materials include the above-mentioned barium titanate, as well as strontium titanate, calcium titanate, magnesium titanate, calcium zirconate, calcium titanate zirconate, barium zirconate, and the like.

[0032] Furthermore, the end margin portion 18 contains boron as a secondary component. As described below, boron functions as a sintering aid that improves the sinterability of ceramics. Specifically, the boron concentration in the end margin portion 18 may be 0.015 atm% or more and 0.025 atm% or less when the element concentration at the B site of the ceramic material (main component) of the end margin portion 18 is 100 atm%. Note that when the main component of the ceramic material of the end margin portion 18 is barium titanate (BaTiO3), the element at the B site is titanium (Ti).

[0033] The side margin portion 17 contains a lower concentration of boron than the end margin portion 18. The boron concentration of the side margin portion 17 may be 70% or less of the boron concentration of the end margin portion 18.

[0034] Even a small amount of boron has the effect of lowering the sintering temperature of ceramic materials. In general, ceramic materials have a higher sintering temperature than metal materials. Therefore, metal materials with lower sintering temperatures begin to shrink at a lower temperature than ceramic materials during firing. If the internal electrodes 12, 13 and the external electrodes 14, 15 shrink relative to the end margin portion 18, they will be separated at the end faces 11a, 11b, making it difficult for the internal electrodes 12, 13 to connect to the external electrodes 14, 15.

[0035] By adding a relatively high concentration of boron to the end margin portion 18, the sintering temperature of the end margin portion 18 can be made close to the sintering temperature of the external electrodes 14, 15 and the internal electrodes 12, 13. That is, the end margin portion 18 can be made to shrink so as to follow the external electrodes 14, 15 and the internal electrodes 12, 13 during firing. This makes it possible to prevent the external electrodes 14, 15 and the internal electrodes 12, 13 from being separated from each other at the end faces 11a, 11b. Therefore, the connection between the first internal electrode 12 and the first external electrode 14, and the connection between the second internal electrode 13 and the second external electrode 15 can be secured, and poor connection of the external electrodes 14, 15 can be prevented.

[0036] Furthermore, by suppressing the boron concentration in the side margin portion 17, it is possible to suppress abnormal grain growth of ceramic particles due to oversintering of the side margin portion 17, which is easily exposed to the firing atmosphere. When the ceramic particles in the side margin portion 17 undergo abnormal grain growth, the microstructure of the ends of the internal electrodes 12, 13 near the side margin portion 17 is destroyed, which tends to lead to the ends becoming spheroidal and fragmented. As a result, the ends of the adjacent internal electrodes 12, 13 may approach or come into contact with each other, which may cause insulation failure such as a short circuit. Therefore, by suppressing oversintering of the side margin portion 17, it is possible to suppress insulation failure of the internal electrodes 12, 13.

[0037] Furthermore, the side margin portion 17 contains silicon. Although silicon also functions as a sintering aid, silicon has a milder effect of increasing sinterability than boron. Therefore, by the side margin portion 17 containing silicon in addition to a low concentration of boron, it is possible to increase the sinterability while suppressing over-sintering. By increasing the sinterability of the side margin portion 17, stress caused by the difference in sintering behavior between the capacitance forming portion 16 and the side margin portion 17 is alleviated during the sintering process. Therefore, structural defects such as cracks between the capacitance forming portion 16 and the side margin portion 17 are prevented, and the associated insulation failure is also suppressed.

[0038] In this embodiment, the end margin portion 18 also contains silicon, but the side margin portion 17 may contain a higher concentration of silicon than the end margin portion 18. The silicon concentration of the side margin portion 17 may be, for example, 2.0 atm% or more when the B-site element concentration of the ceramic material (main component) of the side margin portion 17 is taken as 100 atm%. When the main component of the ceramic material of the side margin portion 17 is barium titanate (BaTiO3), the B-site element is titanium (Ti).

[0039] A method for producing the multilayer ceramic capacitor 10, including the firing step, will now be described in detail.

[0040] [Method of manufacturing multilayer ceramic capacitor 10] Fig. 4 is a flowchart showing a method for manufacturing the multilayer ceramic capacitor 10. Figs. 5 to 9 are diagrams that typically show the manufacturing process of the multilayer ceramic capacitor 10. The method for manufacturing the multilayer ceramic capacitor 10 will be described below along Fig. 4 with appropriate reference to Figs. 5 to 9.

[0041] (Step S11: Forming the internal electrode pattern) In step S11, the internal electrode patterns 112p, 113p are formed on the first ceramic sheet 101 and the second ceramic sheet 102 for forming the capacitance forming portion 16 and the end margin portion 18.

[0042] 5 is a plan view of the ceramic sheets 101 and 102. The ceramic sheets 101 and 102 are formed as unfired dielectric green sheets whose main component is dielectric ceramics. The ceramic sheets 101 and 102 may contain boron, silicon, or the like as a secondary component in addition to the dielectric ceramics that is the main component. The ceramic sheets 101 and 102 are formed into a sheet shape using, for example, a roll coater or a doctor blade.

[0043] At this stage, the ceramic sheets 101 and 102 are configured as large sheets that have not been divided into individual pieces. Fig. 5 shows cutting lines Lx, Ly1, and Ly2 for dividing into individual multilayer ceramic capacitors 10. The cutting line Lx is parallel to the X-axis, and the cutting lines Ly1 and Ly2 are parallel to the Y-axis.

[0044] As shown in FIG. 5, an unsintered first internal electrode pattern 112p corresponding to the first internal electrode 12 is formed on the first ceramic sheet 101, and an unsintered second internal electrode pattern 113p corresponding to the second internal electrode 13 is formed on the second ceramic sheet 102.

[0045] The internal electrode patterns 112p, 113p can be formed by applying any conductive paste to the ceramic sheets 101, 102. The method for applying the conductive paste can be arbitrarily selected from known techniques, and for example, screen printing or gravure printing can be used.

[0046] Each internal electrode pattern 112p on the first ceramic sheet 101 is configured in a band shape extending in the Y-axis direction along the cutting line Ly1. No internal electrode pattern 112p is formed on the cutting line Ly2. Each internal electrode pattern 112p is cut along the cutting lines Ly1, Ly2, and Lx to form the first internal electrode 12 of each multilayer ceramic capacitor 10.

[0047] Each internal electrode pattern 113p on the second ceramic sheet 102 is configured in a band shape extending in the X-axis direction along the cutting line Ly2. The internal electrode pattern 112p is not formed on the cutting line Ly1. In other words, the internal electrode pattern 113p is arranged shifted by one element from the internal electrode pattern 112p in the X-axis direction. Each internal electrode pattern 113p is cut along the cutting lines Ly1, Ly2, and Lx to form the second internal electrode 13 of each multilayer ceramic capacitor 10.

[0048] (Step S12: End margin pattern formation) In step S12, end margin patterns 118p are formed in the areas surrounding the internal electrode patterns 112p, 113p on the first ceramic sheet 101 and the second ceramic sheet .

[0049] 5, the end margin pattern 118p is formed in an area where the internal electrode patterns 112p, 113p are not formed in the ceramic sheets 101, 102. In the first ceramic sheet 101, the end margin pattern 118p is configured as a band area extending along a cutting line Ly2 between the internal electrode patterns 112p adjacent to each other in the X-axis direction. In the second ceramic sheet 102, the end margin pattern 118p is configured as a band area extending along a cutting line Ly1 between the internal electrode patterns 113p adjacent to each other in the X-axis direction.

[0050] The end margin pattern 118p can be formed by applying a ceramic paste to the regions where no electrodes are formed of the ceramic sheets 101 and 102. For example, screen printing or gravure printing can be used to apply the ceramic paste.

[0051] The end margin pattern 118p is cut along the cutting lines Ly1, Ly2, and Lx to form a part of the end margin portion 18. The ceramic paste constituting the end margin pattern 118p is mainly composed of a dielectric ceramic, for example, a ceramic material having a perovskite structure represented by the general formula ABO3 as a main phase. Furthermore, the ceramic paste contains boron and may further contain other sub-components such as silicon.

[0052] (Step S13: Lamination) In step S13, the ceramic sheets 101, 102 and the third ceramic sheet 103 prepared in steps S11 and S12 are laminated as shown in Fig. 6 to produce a laminated sheet 104. The third ceramic sheet 103 is a ceramic sheet on which the internal electrode patterns 112p, 113p and the end margin pattern 118p are not formed.

[0053] The laminated sheet 104 is formed by alternately laminating first ceramic sheets 101 and second ceramic sheets 102 in the Z-axis direction, and a third ceramic sheet 103 is laminated on the top and bottom surfaces in the Z-axis direction. The laminate of the ceramic sheets 101 and 102 corresponds to the capacitance forming portion 16 and the end margin portion 18 after firing. The laminate of the third ceramic sheet 103 corresponds to the cover portion 19 after firing. The number of laminated ceramic sheets 101, 102, and 103 is not limited to the example shown in the figure, and can be adjusted as appropriate.

[0054] The laminated sheet 104 is integrated by pressing the ceramic sheets 101, 102, and 103 together. For example, hydrostatic pressure or uniaxial pressure is preferably used for pressing the ceramic sheets 101, 102, and 103 together. This makes it possible to increase the density of the laminated sheet 104.

[0055] (Step S14: Cutting) In step S14, the laminated sheet 104 obtained in step S13 is cut along cutting lines Lx, Ly1, and Ly2 to produce an unsintered laminated chip 105 as shown in Fig. 7. The laminated chip 105 corresponds to a laminated body consisting of a capacitance forming portion 16, an end margin portion 18, and a cover portion 19.

[0056] That is, the laminated chip 105 has an unsintered capacitance forming portion 116 in which the internal electrodes 112, 113 are alternately laminated with the ceramic layers 120 sandwiched therebetween, unsintered end margin portions 118 provided between the first end face 105a and the second internal electrode 113 and between the second end face 105b and the first internal electrode 112, respectively, and a cover portion 119 covering both sides in the Z-axis direction of the capacitance forming portion 116. The ceramic layers 120 are formed by cutting the ceramic sheets 101, 102.

[0057] End faces 105a and 105b facing the X-axis direction of the laminated chip 105 correspond to the cut surfaces along the cutting lines Ly1 and Ly2, respectively. Side faces 105c and 105d facing the Y-axis direction of the laminated chip 105 correspond to the cut surface along the cutting line Lx. Ends of the unsintered internal electrodes 112 and 113 from which the internal electrode patterns 112p and 113p are cut are exposed from the side faces 105c and 105d.

[0058] (Step S15: Forming side margins) In step S15, side margins 117 are formed on the side surfaces 105c and 105d of the laminated chip 105. In this way, an unsintered ceramic body 111 as shown in FIG.

[0059] Side margin portion 117 includes an unfired ceramic material, and specifically, is formed from a ceramic sheet or ceramic slurry. Side margin portion 117 can be formed, for example, by attaching a ceramic sheet to side surfaces 105c and 105d of laminated chip 105. Side margin portion 117 can also be formed by coating side surfaces 105c and 105d of laminated chip 105 with ceramic slurry, for example, by painting or dipping.

[0060] The side margin portion 117 is mainly composed of a dielectric ceramic, for example, a ceramic material having a perovskite structure represented by the general formula ABO3 as a main phase. Furthermore, the side margin portion 117 may contain secondary components such as boron and silicon.

[0061] As shown in FIG. 8, the ceramic body 111 has a first end face 111a and a second end face 111b facing the X-axis direction, an unsintered capacitance forming portion 116 (see FIG. 7), unsintered end margin portions 118 provided between the first end face 111a and the second internal electrode 113 and between the second end face 111b and the first internal electrode 112, an unsintered side margin portion 117 covering the capacitance forming portion 116 from the Y-axis direction, and an unsintered cover portion 119.

[0062] Fig. 9 is a schematic cross-sectional view of the ceramic body 111, Fig. 9A is a schematic cross-sectional view taken along line CC' in Fig. 8, and Fig. 9B is a schematic cross-sectional view taken along line D-D' in Fig. 8. Note that, for the sake of explanation, Fig. 9 shows fewer internal electrodes 112, 113 and ceramic layers 120 than Fig. 8. Also, in Fig. 9, hatching of the internal electrodes 112, 113 is omitted.

[0063] 9A, the end margin portion 118 of this embodiment is formed by an end margin pattern 118p and a ceramic layer 120 formed by cutting the ceramic sheets 101 and 102. The side margin portion 117 is formed by the above-mentioned ceramic sheet and ceramic slurry.

[0064] In this embodiment, the end margin pattern 118p has a higher boron concentration than the ceramic sheets 101, 102 and the side margin portion 117. For example, the end margin pattern 118p has a boron concentration of 0.15 atm% or more and 0.30 atm% or less when the element concentration of the B site (titanium (Ti) when the main component is barium titanate (BaTiO3)) of the ceramic material of the end margin pattern 118p is 100 atm%. On the other hand, the ceramic sheets 101, 102 (ceramic layers 120) and the side margin portion 117 have a boron concentration of, for example, less than 0.15 atm% when the element concentration of the B site (titanium (Ti) when the main component is barium titanate (BaTiO3)) of the ceramic material of these main components is 100 atm%.

[0065] As a result, the end margin portion 118, which is made up of the end margin pattern 118p and the ceramic sheets 101, 102 (ceramic layer 120), contains a higher concentration of boron than the side margin portion 117 as a whole.

[0066] Furthermore, the side margin portion 117 may contain silicon. The ceramic layer 120 and the end margin pattern 118p may also contain silicon, but, for example, the side margin portion 117 contains a higher concentration of silicon than the ceramic layer 120 and the end margin pattern 118p. The silicon concentration of the side margin portion 117 is, for example, 1.0 atm% or more and 3.0 atm% or less when the element concentration of the B site of the ceramic material of the side margin portion 117 is 100 atm%.

[0067] Since the end margin portions 118 and the side margin portions 117 have the above-mentioned configuration, the end margin portions 118 and the side margin portions 117 exhibit favorable sintering behavior in the firing step described below.

[0068] (Step S16: Forming external electrodes) In step S16, unsintered external electrodes 14, 15 are formed on end faces 111a, 111b of the ceramic body 111 obtained in step S15. The unsintered external electrodes 14, 15 are formed, for example, by applying a conductive paste to the end faces 111a, 111b. The application method is not particularly limited, and a dipping method, a printing method, or the like can be appropriately selected.

[0069] (Step S17: Firing) In step S17, the unsintered ceramic body 111 on which the external electrodes 14, 15 obtained in step S16 are formed is fired to produce the multilayer ceramic capacitor 10 shown in Figures 1 to 3. That is, in step S17, the capacitance forming portion 116 becomes the capacitance forming portion 16, the side margin portion 117 becomes the side margin portion 17, the end margin portion 118 becomes the end margin portion 18, and the cover portion 119 becomes the cover portion 19. The firing can be performed, for example, in a reducing atmosphere or a low oxygen partial pressure atmosphere.

[0070] In step S17, sintering starts first with the internal electrodes 112, 113 and the external electrodes 14, 15 made of a metal having a lower sintering temperature. That is, the internal electrodes 112, 113 and the external electrodes 14, 15 start to shrink before the ceramics.

[0071] In this embodiment, the end margin portion 118 contains a relatively high concentration of boron. As described above, even a small amount of boron has the effect of lowering the sintering temperature. Therefore, the sintering temperature of the end margin portion 118 sandwiched between the external electrodes 14, 15 and the internal electrodes 112, 113 is lowered, and the end margin portion 118 can shrink to follow the external electrodes 14, 15 and the internal electrodes 112, 113. This makes it possible to prevent the external electrodes 14, 15 and the internal electrodes 112, 113 from shrinking more than the end margin portion 118 and separating them. Therefore, the connection between the first internal electrode 12 and the first external electrode 14, and the connection between the second internal electrode 13 and the second external electrode 15 can be ensured.

[0072] On the other hand, the side margin portion 117 contains a lower concentration of boron than the end margin portion 118. While boron is highly effective in improving sinterability, it also carries the risk of promoting oversintering in the side margin portion 117, which is easily exposed to the firing atmosphere. In particular, firing in a reducing atmosphere increases the risk that boron will promote oversintering of the side margin portion 117. When the side margin portion 117 becomes oversintered, grain growth of ceramic particles is promoted in the side margin portion 117, causing excessive grain growth.

[0073] If the ceramic particles in the side margin portion 117 near the internal electrodes 112, 113 (capacitance forming portion 116) grow excessively, the fine layer structure of the internal electrodes 112, 113 may be disturbed. Specifically, the ends of the internal electrodes 112, 113 are affected by the grown ceramic particles and are divided. As a result, the molten internal electrodes become spherical, and the upper and lower internal electrodes in the Z-axis direction get closer to each other, causing a decrease in insulation. In addition, the shape of the internal electrodes changes, causing a decrease in the crossing area and a decrease in capacitance.

[0074] Therefore, by suppressing the boron concentration in the side margin portion 117, the risk of over-sintering and abnormal grain growth can be reduced, and insulation failure of the internal electrodes 12, 13 can be suppressed.

[0075] Furthermore, the side margin portion 117 contains silicon. Silicon has the effect of increasing the sinterability more gradually than boron, suppressing the risk of oversintering, and lowering the firing temperature. In the side margin portion 117, silicon and a small amount of boron work together to suppress oversintering and the abnormal grain growth of ceramic particles associated therewith, while lowering the firing temperature. This makes the side margin portion 17 more likely to shrink in accordance with the shrinkage of the internal electrodes 12, 13, and suppresses the stress generated in the side margin portion 17 due to the shrinkage of the internal electrodes 12, 13. Therefore, structural defects such as cracks between the side margin portion 17 and the capacitance forming portion 16 can be suppressed, and the insulation failure associated therewith can be suppressed.

[0076] The firing temperature in step S17 can be determined based on the sintering temperature of the ceramic body 111. In this embodiment, boron and silicon are added as sintering aids to the ceramic material constituting the ceramic body 111. Therefore, for example, when a barium titanate (BaTiO3)-based material is used, firing at a low temperature of about 1000 to 1200°C becomes possible.

[0077] The above manufacturing method produces the multilayer ceramic capacitor 10. After firing, a plating film may be further formed on the external electrodes 14, 15.

[0078] [Example] As an example of the first embodiment, an example sample of a multilayer ceramic capacitor was produced using the above manufacturing method. In this sample, the dimension in the X-axis direction was about 660 μm, the dimension in the Y-axis direction was about 340 μm, and the dimension in the Z-axis direction was about 300 μm. The firing temperature was selected within the range of 1000 to 1200° C., at which the pore ratio of the side margin portion 17 after firing was 5% or less. Here, the pore ratio is defined as the ratio of the area of ​​the pores in an image of a cross section of the side margin portion 17.

[0079] In the above embodiment sample, the boron concentration of the ceramic sheets 101 and 102 was 0.26 atm% when the elemental concentration of titanium (Ti) contained in barium titanate (BaTiO3), the main component of the ceramic material, was 100 atm%. Similarly, the boron concentration of the end margin pattern 118p was 0.26 atm% when the elemental concentration of titanium was 100 atm%. Similarly, the boron concentration of the side margin portion 117 was 0.13 atm% when the elemental concentration of titanium was 100 atm%.

[0080] Similarly, the silicon concentration of the ceramic sheets 101 and 102 was 2.0 atm% when the elemental concentration of titanium was 100 atm%. Similarly, the silicon concentration of the end margin pattern 118p was 2.0 atm% when the elemental concentration of titanium was 100 atm%. Similarly, the silicon concentration of the side margin portion 117 was 2.0 atm% when the elemental concentration of titanium was 100 atm%.

[0081] In order to confirm the boron concentration distribution and silicon concentration distribution in the produced multilayer ceramic capacitor 10, the boron concentration distribution and silicon concentration distribution in the ceramic body 11 of the multilayer ceramic capacitor 10 were measured by LA-ICP-MS (laser ablation ICP mass spectrometry).

[0082] First, in order to measure the boron concentration distribution and silicon concentration distribution in the side margin portion 17, the ceramic body 11 of the example sample was cut along the YZ plane to prepare a measurement sample with the cut surface facing forward (X-axis direction).

[0083] Next, as shown in Fig. 10, the cut surface of the measurement sample was irradiated with a laser beam multiple times to generate multiple irradiation spots S1. The elemental composition of the particles volatilized from the irradiation spots S1 was then analyzed by LA-ICP-MS.

[0084] The laser beam was irradiated at multiple locations across the Y-axis direction from the side margin 17 on one side surface 11c of the ceramic body 11 to the ceramic layer 20 of the capacitance forming portion 16 and the side margin 17 on the second side surface 11d, generating irradiation spots S1 with a diameter of 10 μm and spot intervals of 20 μm. The laser beam was irradiated under conditions of energy of 11 to 12 J / cm2 at each irradiation spot S1. 2 The frequency was 10 Hz, and the laser irradiation time was 15 seconds. Note that the number of irradiation spots shown in FIG. 10 is smaller than the actual number of irradiation spots.

[0085] Then, based on the number of boron atoms and the number of silicon atoms counted from the fine particles volatilized from the irradiation spot S1, the boron concentration and silicon concentration at each spot position were calculated. The results are shown in Table 1 and FIG.

[0086] Table 1 shows the values ​​of boron concentration (B) and silicon concentration (Si) calculated for each irradiation spot S1. Fig. 11 is a line graph showing the boron concentration distribution corresponding to Table 1. Specifically, Fig. 11 is a graph showing the relationship between the boron concentration (vertical axis) calculated based on the number of particles volatilized from each irradiation spot S1 and the distance in the Y-axis direction from the first side surface 11c of the ceramic body 11 (horizontal axis).

[0087] [Table 1]

[0088] 11, it can be seen that the boron concentration is low in the side margin portions 17 on the sides 11c and 11d, and increases toward the inside of the capacitance forming portion 16 in the Y-axis direction. In fact, as shown in Table 1, the boron concentrations in the side margin portions 17 at 0 μm and 340 μm from the first side surface 11c were 0.009 atm% and 0.010 atm%, respectively. Also, in the ceramic layer 120 of the capacitance forming portion 16 at 40 to 300 μm from the first side surface 11c, the boron concentration was in the range of 0.017 to 0.021 atm%.

[0089] Also, from Table 1, the silicon concentrations in the side margin portion 17 at 0 μm and 340 μm from the first side surface 11c were 2.0 atm% and 2.1 atm%, respectively. Also, in the ceramic layer 120 of the capacitance forming portion 16 at 40 to 300 μm from the first side surface 11c, the silicon concentration was in the range of 1.3 to 1.7 atm%.

[0090] Next, in order to measure the boron concentration distribution and silicon concentration distribution in the end margin portion 18, the ceramic body 11 of the example sample was cut along the XZ plane to prepare a measurement sample with the cut surface facing forward (Y-axis direction).

[0091] Then, as shown in Fig. 12, a laser beam was irradiated onto the cut surface of the measurement sample multiple times to generate multiple irradiation spots S2. The elemental composition of the particles volatilized from the irradiation spots S2 was analyzed by LA-ICP-MS.

[0092] The laser beam was irradiated in multiple spots across the X-axis direction from the end margin 18 on the first end face 11a side of the ceramic body 11 to the ceramic layer 20 of the capacitance forming portion 16 and the end margin 18 on the second end face 11b side, generating irradiation spots S2 with a diameter of 10 μm and spot intervals of 20 μm. The laser beam was irradiated under the same conditions as in the measurement of the side margin 17 side. Note that the number of irradiation spots shown in FIG. 12 is smaller than the actual number of irradiation spots.

[0093] Then, based on the number of boron atoms and the number of silicon atoms counted from the fine particles volatilized from the irradiation spot S2, the boron concentration and silicon concentration at each spot position were calculated. The results are shown in Table 2 and FIG.

[0094] Table 2 shows the calculated values ​​of boron concentration (B) and silicon concentration (Si) in each irradiation spot S2. Fig. 13 is a line graph showing the boron concentration distribution corresponding to Table 2. Specifically, Fig. 13 is a graph showing the relationship between the boron concentration (vertical axis) calculated based on the number of particles volatilized from each irradiation spot S1 and the distance in the Y-axis direction from the first side surface 11c of the ceramic body 11 (horizontal axis).

[0095] [Table 2]

[0096] 13, it was found that the boron concentration in the end margin portion 18 was equivalent to that in the capacitance forming portion 16. As shown in Table 2, the boron concentrations in the end margin portion 18 at 0 μm, 20 μm, 40 μm, 620 μm, 640 μm, and 660 μm from the first end face 11a were 0.021 atm%, 0.018 atm%, 0.021 atm%, 0.017 atm%, 0.021 atm%, and 0.021 atm%, respectively. Also, the boron concentration in the ceramic layer 120 of the capacitance forming portion 16 at 60 to 600 μm from the first end face 11a was in the range of 0.017 to 0.021 atm%.

[0097] Also, as shown in Table 2, the silicon concentrations in end margin portions 18 located at 0 μm, 20 μm, 40 μm, 620 μm, 640 μm, and 660 μm from first end face 11a were 1.9 atm%, 1.8 atm%, 1.7 atm%, 1.5 atm%, 1.8 atm%, and 1.9 atm%, respectively. Also, in ceramic layer 120 of capacitance forming portion 16 located at 60 to 600 μm from first end face 11a, the silicon concentration was in the range of 1.3 to 1.7 atm%.

[0098] From these results, it was confirmed that the end margin portion 18 contains a higher concentration of boron than the side margin portion 17. In addition, it was confirmed that the boron concentration in the end margin portion 18 was not less than 0.015 atm % and not more than 0.025 atm %. It was also confirmed that the side margin portion 17 contained silicon, and contained a higher concentration of silicon than the end margin portion 18.

[0099] Furthermore, when each cut surface of the example sample was observed by a SEM (Scanning Electron Microscope), no structural defects such as cracks were found between the side margin portion 17 and the capacitance forming portion 16. Furthermore, no separation was found between the external electrodes 14, 15 and the internal electrodes 12, 13 at the end faces 11a, 11b.

[0100] Furthermore, when a DC voltage of 4 V was applied to 1,000 samples of this embodiment, and the incidence rate of samples with a resistivity of 1 MΩ or less (IR defect rate) was examined, the IR defect rate was less than 0.5%, which was a very low result. These results confirmed that the multilayer ceramic capacitor 10 of this embodiment can suppress insulation defects and also suppress connection defects between the external electrodes 14, 15 and the internal electrodes 12, 13.

[0101] <Second embodiment> In the above embodiment, the method of manufacturing the green ceramic body 111 has been described by giving a method in which the side margin 117 is later attached, but the method is not limited to this. For example, the side margin may be formed by a dielectric pattern between internal electrode patterns, similar to the end margin. In the following embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0102] [Configuration of multilayer ceramic capacitor 30] Figures 14 and 15 are diagrams showing a multilayer ceramic capacitor 30 in accordance with a second embodiment of the present invention. Figure 14 is a cross-sectional view showing a cut surface of the multilayer ceramic capacitor 30 corresponding to Figure 2. Figure 15 is a cross-sectional view showing a cut surface of the multilayer ceramic capacitor 30 corresponding to Figure 3.

[0103] The multilayer ceramic capacitor 30 includes a ceramic body 31, a first external electrode 14, and a second external electrode 15. The ceramic body 31 has a first end face 31a and a second end face 31b facing the X-axis direction, a first side face 31c and a second side face 31d facing the Y-axis direction, and a first main face 31e and a second main face 31f facing the Z-axis direction. The first external electrode 14 is provided on the first end face 31a. The second external electrode 15 is provided on the second end face 31b.

[0104] The ceramic body 31 has a capacitance generating portion 16, a side margin portion 37, an end margin portion 18, and a cover portion 39. That is, the ceramic body 31 differs from the ceramic body 11 of the first embodiment in the configurations of the side margin portion 37 and the cover portion 39.

[0105] In this embodiment, the side margin portion 37 covers the capacitance generating portion 16 and the end margin portion 18 from the Y-axis direction. The cover portions 39 are provided above and below the capacitance generating portion 16, the end margin portion 18, and the side margin portion 37 in the Z-axis direction.

[0106] The end margin portion 18 contains boron as in the first embodiment. The side margin portion 37 also contains boron at a lower concentration than the end margin portion 18 and silicon as in the first embodiment.

[0107] [Method of manufacturing the multilayer ceramic capacitor 30] Fig. 16 is a flowchart showing a method for manufacturing the multilayer ceramic capacitor 30. Figs. 17 to 19 are diagrams that typically show the manufacturing process of the multilayer ceramic capacitor 30. The method for manufacturing the multilayer ceramic capacitor 30 will be described below along Fig. 16 with appropriate reference to Figs. 17 to 19.

[0108] (Step S21: Forming the internal electrode pattern) In step S21, the internal electrode patterns 212p, 213p are formed on the first ceramic sheet 201 and the second ceramic sheet 202 for forming the capacitance forming portion 16 and the end margin portion 18.

[0109] Fig. 17 is a plan view of the ceramic sheets 201, 202. At this stage, the ceramic sheets 201, 202 are configured as large sheets that have not been singulated. Fig. 17 shows cutting lines Lx, Ly1, Ly2 for singulating into individual multilayer ceramic capacitors 30. The cutting line Lx is parallel to the X-axis, and the cutting lines Ly1, Ly2 are parallel to the Y-axis.

[0110] As shown in FIG. 17, an unsintered first internal electrode pattern 212p corresponding to the first internal electrode 12 is formed on the first ceramic sheet 201, and an unsintered second internal electrode pattern 213p corresponding to the second internal electrode 13 is formed on the second ceramic sheet 202.

[0111] Each internal electrode pattern 212p on the first ceramic sheet 201 is configured in a substantially rectangular shape extending in the X-axis direction across one cutting line Ly1 or Ly2. Each internal electrode pattern 212p is cut along the cutting lines Ly1, Ly2, and Lx to form the first internal electrode 12 of each multilayer ceramic capacitor 30.

[0112] In the first ceramic sheet 201, a first row in which the internal electrode patterns 212p extending across the cutting line Ly1 are arranged along the X-axis direction and a second row in which the internal electrode patterns 212p extending across the cutting line Ly2 are arranged along the X-axis direction are alternately arranged in the Y-axis direction. In the first row, the internal electrode patterns 212p adjacent to each other in the X-axis direction face each other across the cutting line Ly2. In the second row, the internal electrode patterns 212p adjacent to each other in the X-axis direction face each other across the cutting line Ly1. That is, in the first row and the second row adjacent to each other in the Y-axis direction, the internal electrode patterns 212p are arranged shifted by one chip in the X-axis direction.

[0113] The internal electrode pattern 213p on the second ceramic sheet 202 is configured similarly to the internal electrode pattern 212p. However, on the second ceramic sheet 202, the internal electrode pattern 213p in a row corresponding to the first row of the first ceramic sheet 201 extends across the cutting line Ly2, and the internal electrode pattern 213p in a row corresponding to the second row of the first ceramic sheet 201 extends across the cutting line Ly1. In other words, the internal electrode pattern 213p is shifted by one chip in the X-axis or Y-axis direction from the internal electrode pattern 212p.

[0114] (Step S22: End margin pattern formation) In step S22, end margin patterns 218p corresponding to the end margin portions 18 are formed around the internal electrode patterns 212p, 213p of the first ceramic sheet 201 and the second ceramic sheet 202 in the X-axis direction.

[0115] As shown in Fig. 17A, in this embodiment, the end margin pattern 218p in the first ceramic sheet 201 is formed so as to fill the gap between the internal electrode patterns 212p adjacent in the X-axis direction on the cutting lines Ly1, Ly2. As shown in Fig. 17B, the end margin pattern 218p in the second ceramic sheet 202 is similarly formed so as to fill the gap between the internal electrode patterns 213p adjacent in the X-axis direction.

[0116] The end margin pattern 218p contains a dielectric ceramic such as barium titanate (BaTiO3) as a main component, and contains boron and silicon as secondary components.

[0117] (Step S23: Formation of side margin pattern) In step S23, the side margin patterns 237p corresponding to the side margin portions 37 are formed around the internal electrode patterns 212p, 213p of the first ceramic sheet 201 and the second ceramic sheet 202 in the Y-axis direction.

[0118] As shown in Figures 17A and 17B, the side margin pattern 237p is formed in a band-shaped region extending in the X-axis direction including the cutting line Lx. That is, as shown in Figure 17A, the side margin pattern 237p in the first ceramic sheet 201 is formed so as to fill the gap between the internal electrode patterns 212p adjacent in the Y-axis direction. As shown in Figure 17B, the side margin pattern 237p in the second ceramic sheet 202 is formed so as to fill the gap between the internal electrode patterns 213p adjacent in the Y-axis direction.

[0119] The side margin pattern 237p contains a dielectric ceramic such as barium titanate (BaTiO3) as a main component, and contains boron and silicon as secondary components. In this embodiment, the side margin pattern 237p contains a lower concentration of boron than the end margin pattern 218p. The side margin pattern 237p may also contain a higher concentration of silicon than the end margin pattern 218p.

[0120] The order of steps S22 and S23 may be reversed, that is, step S23 may be performed first, and step S22 may be performed after that.

[0121] (Step S24: Lamination) In step S24, the ceramic sheets 201, 202 and the third ceramic sheet 203 prepared in steps S21 and S22 are laminated and pressed together as shown in Fig. 18 to produce a laminated sheet 204. Note that the number of laminated ceramic sheets 201, 202, and 203 is not limited to the example shown in the figure.

[0122] (Step S25: Cutting) In step S25, the laminated sheet 204 obtained in step S24 is cut along the cutting lines Lx, Ly1, and Ly2 to produce unsintered ceramic bodies 231.

[0123] Fig. 19 is a schematic cross-sectional view of the ceramic body 231, with Fig. 19A being a cross-sectional view showing a cut surface corresponding to Fig. 9A, and Fig. 19B being a cross-sectional view showing a cut surface corresponding to Fig. 9B. Note that in Fig. 19, the number of internal electrodes 212, 213 and ceramic layers 220 is shown to be smaller than in Figs. 14 and 15 for the sake of explanation. Also, hatching of the internal electrodes 212, 213 is omitted in Fig. 19.

[0124] As shown in these figures, the ceramic body 231 has a first end face 231a and a second end face 231b facing the X-axis direction, an unsintered capacitance forming portion 216 in which internal electrodes 212, 213 are alternately stacked with a ceramic layer 220 sandwiched between them, unsintered end margin portions 218 provided between the first end face 231a and the second internal electrode 213 and between the second end face 231b and the first internal electrode 212, respectively, and an unsintered side margin portion 237 covering the capacitance forming portion 216 from the Y-axis direction.

[0125] 19A, the end margin portion 218 is formed by an end margin pattern 218p and a ceramic layer 220 obtained by cutting the ceramic sheets 201 and 202. The side margin portion 237 is formed by a ceramic layer 220 obtained by cutting the ceramic sheets 201 and 202 and a side margin pattern 237p.

[0126] As in the first embodiment, the end margin pattern 218p has a higher boron concentration than the ceramic sheets 201 and 202 and the side margin pattern 237p. For example, when the element concentration at the B site of the ceramic material of the end margin pattern 218p is 100 atm%, the end margin pattern 218p has a boron concentration of 0.15 atm% or more and 0.30 atm% or less. On the other hand, when the element concentration at the B site of these ceramic materials is 100 atm%, the ceramic sheets 101 and 102 (ceramic layers 220) and the side margin portion 237 have a boron concentration of less than 0.15 atm%.

[0127] As a result, the end margin portion 218 consisting of the end margin pattern 218p and the ceramic sheets 201, 202 (ceramic layer 220) contains a higher concentration of boron overall than the side margin portion 237 consisting of the side margin pattern 237p and the ceramic sheets 201, 202 (ceramic layer 220).

[0128] Furthermore, the side margin pattern 237p may contain silicon. The ceramic sheets 201, 202 (ceramic layer 220) and the end margin pattern 218p may also contain silicon, but for example, the side margin pattern 237p may contain silicon at a higher concentration than the ceramic sheets 201, 202 (ceramic layer 220) and the end margin pattern 218p.

[0129] (Step S26: Forming external electrodes) In step S26, similar to step S16 in the first embodiment, unsintered external electrodes 14, 15 are formed on the end faces 231a, 231b of the ceramic body 231 obtained in step S25.

[0130] (Step S27: Firing) In step S27, the green ceramic body 231 obtained in step S26 with the green external electrodes 14, 15 formed thereon is fired to produce the ceramic body 31 of the multilayer ceramic capacitor 30 shown in Figures 14 and 15. That is, by step S27, the capacitance forming portion 216 becomes the capacitance forming portion 16, the side margin portion 237 becomes the side margin portion 37, the end margin portion 218 becomes the end margin portion 18, and the cover portion 239 becomes the cover portion 39. The firing can be performed, for example, in a reducing atmosphere or a low oxygen partial pressure atmosphere.

[0131] In the present embodiment, as in the first embodiment, the end margin portion 218 contains boron, which suppresses the shrinkage of the external electrodes 14, 15 and the internal electrodes 212, 213 relative to the end margin portion 218. This ensures the connection between the first internal electrode 12 and the first external electrode 14, and between the second internal electrode 13 and the second external electrode 15.

[0132] On the other hand, since the side margin portion 237 contains boron at a lower concentration than the end margin portion 218, excessive grain growth of ceramic particles is suppressed, and the microstructure of the internal electrodes 12, 13 can be maintained. This makes it possible to suppress insulation failure of the internal electrodes 12, 13. Furthermore, since the side margin portion 237 contains silicon, silicon has the effect of lowering the sintering temperature in cooperation with boron. This makes it easier for the side margin portion 37 to shrink in accordance with the shrinkage of the internal electrodes 12, 13, and suppresses structural defects such as cracks between the side margin portion 37 and the capacitance forming portion 16, thereby making it possible to suppress insulation failure associated therewith.

[0133] <Third embodiment> In the second embodiment, both the end margin pattern 218p and the side margin pattern 237p are formed in steps S22 and S23 of the manufacturing method of the multilayer ceramic capacitor 30. However, as shown in the following third embodiment, only the end margin pattern 218p may be formed without forming the side margin pattern.

[0134] Fig. 20 is a schematic cross-sectional view of an unsintered ceramic body 331 of the third embodiment, with Fig. 20A being a cross-sectional view showing a cut surface corresponding to Fig. 9A, and Fig. 20B being a cross-sectional view showing a cut surface corresponding to Fig. 9B. Note that in Fig. 20, the number of internal electrodes 312, 313 and ceramic layers 320 is shown to be smaller than in Figs. 14 and 15 for the sake of explanation. Also, hatching of the internal electrodes 312, 313 is omitted in Fig. 20.

[0135] As shown in these figures, the ceramic body 331 has a first end face 331a and a second end face 331b facing the X-axis direction, an unsintered capacitance forming portion 316 in which internal electrodes 312, 313 are alternately stacked with a ceramic layer 320 in between, an unsintered end margin portion 318 provided between the first end face 331a and the second internal electrode 313 and between the second end face 331b and the first internal electrode 312, an unsintered side margin portion 337 covering the capacitance forming portion 316 from the Y-axis direction, and an unsintered cover portion 339 covering the capacitance forming portion 316 from the Z-axis direction.

[0136] 20A, the end margin portion 318 is formed by a ceramic layer 320 cut from a ceramic sheet and an end margin pattern 318p. In this embodiment, the side margin portion 337 is formed by a ceramic layer 320 cut from a ceramic sheet.

[0137] The side margin portion 337 of the present embodiment has a smaller number of layers than the capacitance forming portion 316 and the end margin portion 318. Therefore, the side margin portion 337 is compressed from the Z-axis direction, so that the thickness in the Z-axis direction becomes thinner than the capacitance forming portion 316 and the end margin portion 318.

[0138] As in the first embodiment, the end margin pattern 318p has a higher boron concentration than the ceramic sheet (ceramic layer 320). As a result, the end margin portion 318 consisting of the end margin pattern 318p and the ceramic layer 320 contains a higher concentration of boron as a whole than the side margin portion 337 consisting of only the ceramic layer 320.

[0139] Furthermore, the ceramic sheet (ceramic layer 320) may contain silicon. The end margin pattern 318p may also contain silicon, but for example, the ceramic sheet (ceramic layer 320) may contain a higher concentration of silicon than the end margin pattern 118p. As a result, the side margin portion 337 as a whole may contain a higher concentration of silicon than the end margin pattern 318p and the end margin portion 318 made of the ceramic sheet.

[0140] Such a ceramic body 331 is fired after external electrodes 14, 15 are formed on end faces 331a, 331b, thereby producing a multilayer ceramic capacitor 30 having a configuration as shown in Figures 14 and 15.

[0141] In the present embodiment, as in the first embodiment, the end margin portion 318 contains boron, which suppresses the shrinkage of the external electrodes 14, 15 and the internal electrodes 312, 313 relative to the end margin portion 318. This ensures the connection between the first internal electrode 12 and the first external electrode 14, and between the second internal electrode 13 and the second external electrode 15.

[0142] Furthermore, since the side margin portion 337 contains boron at a lower concentration than the end margin portion 318, excessive grain growth of ceramic particles is suppressed, and the microstructure of the internal electrodes 12, 13 can be maintained. This makes it possible to suppress insulation failure of the internal electrodes 12, 13. Furthermore, since the side margin portion 337 contains silicon, silicon has the effect of lowering the sintering temperature in cooperation with boron. This makes it easier for the side margin portion 37 to shrink in accordance with the shrinkage of the internal electrodes 12, 13, and suppresses structural defects such as cracks between the side margin portion 37 and the capacitance forming portion 16, thereby making it possible to suppress insulation failure associated therewith.

[0143] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the present invention. For example, the present invention can be implemented as an embodiment in which the various embodiments are combined.

[0144] In addition, while the multilayer ceramic capacitors 10 and 30 have been described as examples of multilayer ceramic electronic components in the above embodiments, the present invention is applicable to all multilayer ceramic electronic components having a pair of external electrodes. Examples of such multilayer ceramic electronic components include chip varistors, chip thermistors, and multilayer inductors. [Explanation of symbols]

[0145] 10,30...Multilayer ceramic capacitors (multilayer ceramic electronic components) 11,31…Ceramic body 111, 231, 331…Unfired ceramic body 11a, 31a, 111a, 231a, 331a...first end surface 11b, 31b, 111b, 231b, 331b...Second end surface 12,13,112,113,212,213,312,313…Internal electrode 14,15...External electrode 16,116,216,316...Capacity forming section (functional section) 17, 37, 117, 237, 337…Side margin 18,118,218,318…End margin section 20,120,220,320…ceramic layer

Claims

1. a ceramic body having a first end face and a second end face each facing a first direction, a functional section in which a first internal electrode extended to the first end face and a second internal electrode extended to the second end face are stacked with a ceramic layer therebetween in a second direction perpendicular to the first direction, end margins provided between the first end face and the second internal electrode and between the second end face and the first internal electrode, respectively, and a side margin covering the functional section from a third direction perpendicular to the first direction and the second direction; external electrodes provided on the first end surface and the second end surface; Equipped with the end margin portion includes boron (B) and silicon (Si) having a higher concentration than the boron; The side margin portion includes silicon (Si) having a higher concentration than the end margin portion, and boron having a lower concentration than the silicon and a lower concentration than the end margin portion. Multilayer ceramic electronic components.

2. 2. The multilayer ceramic electronic component according to claim 1, The end margin portion has the general formula ABO ３ The main component is a ceramic material having a perovskite structure as the main phase, When the element concentration at the B site of the ceramic material at the end margin portion is taken as 100 atm %, the boron concentration at the end margin portion is 0.015 atm % or more and 0.025 atm % or less. Multilayer ceramic electronic components.

3. 3. The multilayer ceramic electronic component according to claim 1, The boron concentration in the side margin portion is 70% or less of the boron concentration in the end margin portion. Multilayer ceramic electronic components.

4. 4. The multilayer ceramic electronic component according to claim 1, The positions of the ends of the first internal electrode and the second internal electrode in the third direction are aligned to within a range of 0.5 μm in the third direction. Multilayer ceramic electronic components.

5. an unsintered ceramic body is fabricated, the unsintered ceramic body having: a first end face and a second end face each facing a first direction; a functional section in which a first internal electrode extended to the first end face and a second internal electrode extended to the second end face are stacked on top of each other with a ceramic layer sandwiched therebetween in a second direction perpendicular to the first direction; end margin sections each provided between the first end face and the second internal electrode and between the second end face and the first internal electrode, the end margin sections containing boron (B) and silicon (Si) at a higher concentration than the boron; and a side margin section covering the functional section from a third direction perpendicular to the first and second directions, the side margin section containing silicon (Si) at a higher concentration than the end margin section and boron at a lower concentration than the silicon and lower than the end margin section; forming unfired external electrodes on the first end surface and the second end surface, sintering the green ceramic body on which the green external electrodes are formed; A method for manufacturing multilayer ceramic electronic components.

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