Multilayer ceramic capacitor

Abstract

The present invention provides a multilayer ceramic capacitor in which a resin electrode releases stress more and cracks are less likely to occur in a ceramic element body. This multilayer ceramic capacitor 1 comprises: a ceramic element body 2 which includes a plurality of stacked dielectric layers and a plurality of stacked internal electrode layers, and which has a first main surface 3 and a second main surface 4 that are opposite to each other in the height direction T, a first side surface 5 and a second side surface 6 that are opposite to each other in the width direction W which is orthogonal to the height direction T, and a first end surface 7 and a second end surface 8 that are opposite to each other in the length direction L which is orthogonal to the height direction T and the width direction W; and a terminal electrode which is provided on the ceramic element body 2 and is connected to a part of the internal electrode layers. The terminal electrode includes a resin electrode 23, the resin electrode 23 contains a resin and a conductive filler, the average particle diameter of the filler is 5 μm or more, and the average aspect ratio of the filler is 4 or more.

Description

Multilayer ceramic capacitors

[0001] The present invention relates to a multilayer ceramic capacitor.

[0002] Regarding terminal electrodes of multilayer ceramic capacitors, there are terminal electrodes containing resin electrodes. Patent Document 1 describes a resin electrode containing copper powder and epoxy resin.

[0003] When the terminal electrodes include resin electrodes, the resin electrodes can release stress applied to the multilayer ceramic capacitor because cracks are generated inside the resin electrodes, releasing the stress. As a result, cracks are prevented from occurring in the ceramic body.

[0004] JP 2014-160791 A

[0005] However, conventional resin electrodes have the problem of insufficient stress relief. Therefore, an object of the present invention is to provide a multilayer ceramic capacitor in which resin electrodes further relieve stress and cracks are less likely to occur in the ceramic body.

[0006] The multilayer ceramic capacitor of the present invention is a multilayer ceramic capacitor comprising: a ceramic body including a plurality of laminated dielectric layers and a plurality of laminated internal electrode layers, the ceramic body having first and second main surfaces opposing each other in a height direction, first and second side surfaces opposing each other in a width direction perpendicular to the height direction, and first and second end faces opposing each other in a length direction perpendicular to the height and width directions; and terminal electrodes provided on the ceramic body and connected to some of the internal electrode layers, the terminal electrodes including resin electrodes containing resin and a conductive filler, the filler having an average particle size of 5 μm or more and an average aspect ratio of 4 or more.

[0007] According to the present invention, it is possible to provide a multilayer ceramic capacitor in which the resin electrodes further release stress and cracks are less likely to occur in the ceramic body.

[0008] 1 is a perspective view of a multilayer ceramic capacitor according to an embodiment of the present invention; FIG. 2 is a cross-sectional view taken along line II in FIG. 1; FIG. 3 is a cross-sectional view taken along line II in FIG. 1; FIG. 4 is a conceptual diagram of a cross-section of a terminal electrode according to an embodiment of the present invention; FIG. 5 is a conceptual diagram of a cross-section of a conventional terminal electrode; FIG. 6 is a diagram showing a scanning electron microscope image of a cross-section of a terminal electrode according to an embodiment of the present invention; FIG. 7 is a diagram showing a scanning electron microscope image of a cross-section of a conventional terminal electrode; and FIG. 8 is a diagram showing a method of forming a resin electrode.

[0009] An embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a perspective view of a multilayer ceramic capacitor 1 according to an embodiment of the present invention. FIG. 1 shows a so-called two-terminal multilayer ceramic capacitor. The multilayer ceramic capacitor 1 of the present invention is not limited to a two-terminal multilayer ceramic capacitor. The multilayer ceramic capacitor 1 of the present invention may also be a multi-terminal multilayer ceramic capacitor, such as a three-terminal multilayer ceramic capacitor.

[0010] The multilayer ceramic capacitor 1 includes a ceramic body 2 and terminal electrodes. The terminal electrodes include a first terminal electrode 20 and a second terminal electrode 21.

[0011] The ceramic body 2 includes a plurality of laminated dielectric layers and a plurality of internal electrode layers, and is shaped like a substantially rectangular parallelepiped.

[0012] In the ceramic body 2, the direction in which the dielectric layers and internal electrode layers are stacked is defined as a height direction T. The direction perpendicular to the height direction T is defined as a width direction W. The direction perpendicular to the height direction T and the width direction W is defined as a length direction L.

[0013] Of the two surfaces of the ceramic body 2 that face each other in the height direction T, one surface is designated as a first main surface 3. The remaining surface is designated as a second main surface 4. Of the two surfaces of the ceramic body 2 that face each other in the width direction W, one surface is designated as a first side surface 5. The remaining surface is designated as a second side surface 6. Of the two surfaces of the ceramic body 2 that face each other in the length direction L, one surface is designated as a first end surface 7. The remaining surface is designated as a second end surface 8.

[0014] 1 is referred to as an LT cross section, and the cross section of the ceramic body 2 taken along line II in FIG. 1 is referred to as a WT cross section.

[0015] The intersection of three faces of the ceramic body 2 is called a corner of the ceramic body 2. The intersection of two faces of the ceramic body 2 is called a ridge of the ceramic body 2. The corners and ridges are preferably rounded.

[0016] The total number of dielectric layers stacked on the ceramic body 2 is preferably 15 or more and 2000 or less. The main material of the dielectric layers is a ceramic material. Examples of ceramic materials include dielectric ceramics containing barium titanate, calcium titanate, strontium titanate, calcium zirconate, or the like as main components. The ceramic material may also be a dielectric ceramic containing these main components plus a secondary component such as a manganese compound, an iron compound, a chromium compound, a cobalt compound, or a nickel compound.

[0017] The thickness of each dielectric layer is preferably 0.3 μm or more and 10 μm or less.

[0018] The division of the ceramic body 2 in the length direction L will be described with reference to Figure 2. Figure 2 is a cross-sectional view taken along line II in Figure 1. The ceramic body 2 can be divided into a first main surface side outer layer portion 10, an effective portion 11, and a second main surface side outer layer portion 12 in the height direction T.

[0019] The first main surface side outer layer portion 10 is the portion between the first main surface 3 and the internal electrode layer closest to the first main surface 3. The effective portion 11 is the portion where the internal electrode layers face each other. The second main surface side outer layer portion 12 is the portion between the second main surface 4 and the internal electrode layer closest to the second main surface 4.

[0020] Of the dielectric layers, the dielectric layers arranged in the first main surface side outer layer portion 10 and the second main surface side outer layer portion 12 are referred to as outer dielectric layers 30. Of the dielectric layers, the dielectric layer arranged in the effective portion 11 is referred to as inner dielectric layers 31.

[0021] The size of the ceramic body 2 is not particularly limited. The length L of the ceramic body is preferably 0.2 mm or more and 10 mm or less. The length W of the ceramic body 2 in the width direction is preferably 0.1 mm or more and 5 mm or less. The length T of the ceramic body 2 in the height direction is preferably 0.1 mm or more and 5 mm or less.

[0022] The division of the ceramic body 2 in the longitudinal direction L will be described. The ceramic body 2 can be divided into a first end face side outer layer portion 13, a longitudinally facing portion 14, and a second end face side outer layer portion 15 in the longitudinal direction L.

[0023] The longitudinal facing portion 14 is a portion where internal electrode layers face each other in the height direction T. The first end face side outer layer portion 13 is a portion between the longitudinal facing portion 14 and the first end face 7. The second end face side outer layer portion 15 is a portion between the longitudinal facing portion 14 and the second end face 8.

[0024] The longitudinally opposing portions 14 correspond to opposing electrode portions of the internal electrode layers. The first end surface side outer layer portion 13 and the second end surface side outer layer portion 15 correspond to lead electrode portions of the internal electrode layers. The first end surface side outer layer portion 13 and the second end surface side outer layer portion 15 are also called L gaps.

[0025] The division of the ceramic body 2 in the width direction W will be described with reference to Figure 3. Figure 3 is a cross-sectional view taken along line II-II in Figure 1. The ceramic body 2 can be divided in the width direction W into a first side surface outer layer portion 16, a widthwise opposing portion 17, and a second side surface outer layer portion 18.

[0026] The widthwise facing portion 17 is a portion where internal electrode layers face each other in the height direction T. The first side surface side outer layer portion 16 is a portion between the widthwise facing portion 17 and the first side surface 5. The second side surface side outer layer portion 18 is a portion between the widthwise facing portion 17 and the second side surface 6.

[0027] The first side surface side outer layer portion 16 and the second side surface side outer layer portion 18 are portions where no internal electrode layers exist in the height direction T. The first side surface side outer layer portion 16 and the second side surface side outer layer portion 18 are also called W gaps.

[0028] The internal electrode layers include a plurality of first internal electrode layers 32 and a plurality of second internal electrode layers 33. The first internal electrode layers 32 are internal electrode layers exposed at the first end face 7. The second internal electrode layers 33 are internal electrode layers exposed at the second end face 8.

[0029] The first internal electrode layer 32 can be divided into a first opposing electrode portion 34 and a first lead electrode portion 36. The first opposing electrode portion 34 is a portion that faces the second internal electrode layer 33. The first lead electrode portion 36 is a portion that is led from the first opposing electrode portion 34 to the first end face 7 of the ceramic body 2.

[0030] The second internal electrode layer 33 can be divided into a second opposing electrode portion 35 and a second lead electrode portion 37. The second opposing electrode portion 35 is a portion that faces the first internal electrode layer 32. The second lead electrode portion 37 is a portion that is led from the second opposing electrode portion 35 to the second end face 8 of the ceramic body 2.

[0031] The material of the internal electrode layers can be, for example, a metal such as nickel, copper, silver, palladium, gold, etc. The material of the internal electrode layers can be an alloy containing at least one of the aforementioned metals, such as a silver-palladium alloy.

[0032] In the multilayer ceramic capacitor 1, capacitance is formed by the first opposing electrode portion 34 and the second opposing electrode portion 35 facing each other via the inner dielectric layer 31. This allows the multilayer ceramic capacitor 1 to exhibit capacitor characteristics.

[0033] The thickness of the internal electrode layer is preferably, for example, about 0.2 μm or more and 2.0 μm or less. The total number of the first internal electrode layers 32 and the second internal electrode layers 33 is preferably 15 or more and 2000 or less.

[0034] The terminal electrodes will now be described. The terminal electrodes include a first terminal electrode 20 and a second terminal electrode 21. The first terminal electrode 20 is a terminal electrode connected to a first internal electrode layer 32. The second terminal electrode 21 is a terminal electrode connected to a second internal electrode layer 33.

[0035] The first terminal electrode 20 is arranged on the first end face 7, part of the first main surface 3, part of the second main surface 4, part of the first side surface 5, and part of the second side surface 6. The second terminal electrode 21 is arranged on the second end face 8, part of the first main surface 3, part of the second main surface 4, part of the first side surface 5, and part of the second side surface 6.

[0036] The terminal electrodes include a base electrode 22, a resin electrode 23, a nickel-plated film 24, and a tin-plated film 25. These are arranged in this order from the end face of the ceramic body 2: base electrode 22, resin electrode 23, nickel-plated film 24, tin-plated film 25.

[0037] The base electrode 22 is disposed on and covers the end face of the ceramic body 2. The base electrode 22 extends from the end face to a part of the main surface and a part of the side face.

[0038] The base electrode 22 includes glass and metal. The glass includes at least one selected from boron, silicon, barium, magnesium, aluminum, lithium, etc. The metal includes at least one selected from copper, nickel, silver, palladium, a silver-palladium alloy, gold, etc. The base electrode 22 is formed by applying a conductive paste containing glass and metal to the ceramic body 2 and firing the paste. The thickness of the base electrode 22 is preferably, for example, 3 μm or more and 150 μm or less.

[0039] The resin electrode 23 is disposed so as to cover the base electrode 22. The resin electrode 23 contains resin and metal. The resin electrode 23 is more flexible than the base electrode 22 because it contains resin.

[0040] The resin electrode 23 functions as a buffer layer, so that when a bending stress is applied to the mounting substrate and this stress applies a physical force to the multilayer ceramic capacitor 1, the multilayer ceramic capacitor 1 is less likely to crack.

[0041] Furthermore, when a force due to a thermal cycle is applied to the multilayer ceramic capacitor 1, cracks are unlikely to occur in the multilayer ceramic capacitor 1.

[0042] The resin contained in the resin electrode 23 can be a thermosetting resin such as an epoxy resin, a phenolic resin, a urethane resin, a silicone resin, or a polyimide resin. Among these resins, an epoxy resin is one of the most suitable resins. An epoxy resin has excellent heat resistance, moisture resistance, and adhesion. Alternatively, multiple types of resins, such as an epoxy resin and a phenolic resin, may be used.

[0043] The resin electrode 23 preferably contains a curing agent in addition to the resin. When an epoxy resin is used as the resin, the curing agent is preferably a phenol-based, amine-based, acid anhydride-based, imidazole-based, active ester-based, or amide-imide-based compound.

[0044] The resin electrode 23 contains a metal. The resin electrode 23 becomes electrically conductive due to the inclusion of the metal in the resin electrode 23. The metal contained in the resin electrode 23 is contained in the resin electrode 23 as metal powder, i.e., filler. The filler contained in the resin electrode 23 has a flat shape. Contact between the fillers forms an electrical path inside the resin electrode 23. The formed electrical path enables the resin electrode 23 to be electrically conductive.

[0045] The metal contained in the resin electrode 23 may be silver, copper, nickel, tin, bismuth, or an alloy containing any of these. It is particularly preferable that the metal contains silver. The silver may be elemental silver. Alternatively, the silver may be an alloy containing silver. For example, the metal may be at least one of silver, silver-coated copper, and silver-coated alloy powder.

[0046] The nickel plating film 24 is disposed so as to cover the resin electrode 23. The tin plating film 25 is disposed so as to cover the nickel plating film 24.

[0047] The nickel plating film 24 can prevent the resin electrode 23 from being eroded by solder when mounting the multilayer ceramic capacitor 1. The tin plating film 25 can improve the wettability of the solder when mounting the multilayer ceramic capacitor 1, making mounting easier.

[0048] The size of the multilayer ceramic capacitor 1 is not particularly limited. The length in the longitudinal direction of the multilayer ceramic capacitor 1 including the ceramic body 2 and the terminal electrodes is preferably 0.2 mm or more and 10 mm or less. The length in the height direction of the multilayer ceramic capacitor 1 including the ceramic body 2 and the terminal electrodes is preferably 0.1 mm or more and 5 mm or less. The length in the width direction of the multilayer ceramic capacitor 1 including the ceramic body 2 and the terminal electrodes is preferably 0.1 mm or more and 10 mm or less.

[0049] In the multilayer ceramic capacitor 1 of this embodiment, when stress is applied to the multilayer ceramic capacitor 1, continuous fractures are likely to occur in the resin electrodes 23. Therefore, the stress applied to the multilayer ceramic capacitor 1 is easily released. As a result, cracks are less likely to occur in the ceramic body 2.

[0050] The internal breakdown of the resin electrode 23 will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a conceptual cross-sectional view of the terminal electrode of this embodiment. Fig. 5 is a conceptual cross-sectional view of a conventional terminal electrode.

[0051] An arrow 52 shown in Figures 4 and 5 indicates the thickness direction of the resin electrode 23. Figures 4 and 5 show cross sections parallel to the thickness direction 52 of the resin electrode 23. An arrow 54 shown in Figures 4 and 5 indicates a direction parallel to the surface of the ceramic body 2. An arrow 56 shown in Figures 4 and 5 indicates a direction along the surface 27, which is the outer surface of the resin electrode 23. If a nickel plating film 24 is disposed on the surface 27 of the resin electrode 23, the arrow 56 would be a direction along the inner surface of the nickel plating film 24. A dashed line 50 shown in Figures 4 and 5 indicates damage that occurs in the resin electrode 23.

[0052] The filler 42 contained in the resin electrode 23 of this embodiment has a flat shape. The average aspect ratio of the filler 42 is 4 or more. Therefore, as shown in FIG. 4 , the filler 42 is observed to have a rectangular shape in a cross section parallel to the thickness direction 52 of the resin electrode 23. The longitudinal direction of this rectangular shape is indicated by an arrow 46. The longitudinal direction 46 of the observed rectangular shape is approximately the direction 54 of the surface of the ceramic body 2 or the direction 56 along the surface of the nickel plating film 24.

[0053] As shown in FIG. 4, in the resin electrode 23 of this embodiment, the broken line 50 indicating the breakdown extends long along the direction 54 or the direction 56 .

[0054] This is because the fracture propagates along the surfaces of the multiple fillers 42. In the resin electrode 23 of this embodiment, the fillers 42 have a flat shape. Furthermore, the longitudinal direction 46 of the fillers 42 is aligned with the surface direction 54 of the ceramic body 2 or the direction 56 along the surface of the nickel plating film 24. Therefore, fractures tend to connect along the longitudinal direction 46 of the fillers 42.

[0055] Furthermore, the average particle size of the filler 42 contained in the resin electrode 23 of this embodiment is 5 μm or more. This reduces the proportion of the resin portion in the path of the breakdown. As a result, the progression of the breakdown can be prevented from being interrupted. This is explained below.

[0056] 4 indicates the distance that the fracture propagates along the filler 42. The arrow 72 in FIG. 4 indicates the distance that the fracture propagates through the resin 40.

[0057] In the resin electrode 23 of this embodiment, the longitudinal direction 46 of the filler 42 is aligned, and the average particle size is 5 μm or more. Therefore, the proportion of the portion 70 in the fracture path where the fracture propagates along the filler 42 can be increased. In other words, the proportion of the portion 72 where the fracture propagates through the resin 40 can be reduced.

[0058] The fracture is less likely to be interrupted in the portion where it propagates along the filler 42. On the other hand, the fracture is more likely to be interrupted in the portion where it propagates through the resin 40. In this embodiment, the proportion of the portion 70 where the fracture propagates along the filler 42 is large, and the proportion of the portion 72 where the fracture propagates through the resin 40 can be reduced. Therefore, the fracture does not get interrupted midway, and the length of the fracture can be increased.

[0059] In this embodiment, the fracture is, for example, 5 μm or more after a substrate bending crack test, which will be described later.

[0060] In contrast, in a conventional resin electrode 23, even if fracture occurs, the fracture is less likely to progress. This will be explained with reference to Figure 5. As a conventional example, a resin electrode 23 using spherical filler particles 42 will be explained. As shown in Figure 5, when the filler particles 42 are spherical, the filler particles 42 do not exhibit any particular orientation with respect to a direction 54 of the surface of the ceramic body 2 or a direction 56 along the surface of the nickel plating film 24.

[0061] 5 indicates the distance that the fracture propagates along the filler 42, as in FIG. 4. Arrow 72 in FIG. 5 indicates the distance that the fracture propagates through the resin 40, as in FIG. 4.

[0062] As shown in Figure 5, in the conventional resin electrode 23, compared to the resin electrode 23 of this embodiment shown in Figure 4, the length of the portion 70 where the fracture propagates along the filler 42 is shorter, and the length of the portion 72 where the fracture propagates through the resin 40 is longer. Therefore, the fracture is likely to be interrupted in the portion where the fracture propagates through the resin 40. For example, the fracture is likely to be interrupted in a location where the length of the portion 72 where the fracture propagates through the resin 40 is long, such as the X mark 58 shown in Figure 5. Therefore, the fracture is unlikely to propagate over a long distance. As a result, stress is not easily released in the terminal electrode, and cracks are likely to occur in the ceramic body 2.

[0063] The progression of fracture will be described more specifically with reference to Figures 6 and 7. Figure 6 is a scanning electron microscope image of a cross section of the terminal electrode of this embodiment. Figure 7 is a scanning electron microscope image of a cross section of a conventional terminal electrode. Both Figures 6 and 7 show the state after a substrate bending crack test, which will be described later.

[0064] 6 , in the resin electrode 23 of this embodiment, the filler 42 is oriented in a direction 54 of the surface of the ceramic body 2 near the interface with the ceramic body 2. Furthermore, the filler 42 is oriented in a direction 56 along the surface of the nickel plating film 24 near the surface 27 of the resin electrode 23.

[0065] 6, the breakdown 50 continues to grow within the resin electrode 23. An arrow 44 in FIG.

[0066] 6 shows a fracture 50 near the surface 27 of the resin electrode 23. The fracture 50 can also occur in the resin electrode 23 near the interface with the ceramic body 2.

[0067] The vicinity of the interface or the vicinity of the surface refers to, for example, a range of 5 μm from the interface or the surface.

[0068] In contrast, in the conventional terminal electrode, the breakdown 50 does not progress continuously within the resin electrode 23. As shown in Fig. 7, the breakdown 50 progresses in a direction 44 of the progress of the breakdown 50, but is interrupted. Line 47 in Fig. 6 and line 48 in Fig. 7 are lines drawn to match the breakdown 50. As shown by line 47 in Fig. 6, in this embodiment, the line 47 indicating the breakdown 50 is continuous. In contrast, as shown by line 48 in Fig. 7, the line 48 indicating the breakdown 50 in the conventional resin electrode 23 is discontinuous.

[0069] The particle size of the filler 42 and the results of the crack generation test will be described based on Table 1. First, the measurement method and test method will be described.

[0070] The particle size shown in Table 1 is the average particle size of D50 of the filler 42. The aspect ratio is the major axis diameter / minor axis diameter of the filler 42.

[0071] The particle size and aspect ratio are average values ​​determined by analyzing scanning electron microscope images.

[0072] The scanning electron microscope image is the result of observing the LT cross section of the second terminal electrode 21 in an area of ​​50 μm×80 μm in a state where the electrode was polished in the width direction W up to the center position in the width direction W.

[0073] The proportion of filler 42 oriented in the direction along the interface near the interface is the proportion of filler 42 oriented in the direction along surface 27 or the interface with ceramic body 2 within a range of 5 μm from surface 27 facing nickel plating film 24 and within a range of 5 μm from the interface with ceramic body 2. Here, "along" means that the angle between the longitudinal direction of filler 42 and surface 27 or the interface with ceramic body 2 is 10 degrees or less.

[0074] The distance between fillers in a direction perpendicular to the surface of the ceramic body refers to the distance between the fillers 42 at which the distance in the perpendicular direction is shortest for each filler 42 .

[0075] The proportion of filler 42 oriented in the direction along the interface near the interface and the distance between fillers in the direction perpendicular to the surface of the ceramic body are average values ​​obtained by analyzing scanning electron microscope images in the same manner as in the measurement of particle size.

[0076] The degree of orientation is a value determined by analyzing an SEM image using image processing software.

[0077] The thermal shock crack test was performed under the following conditions. One cycle consisted of holding the test sample chip at a temperature between +0°C and -3°C above the minimum operating temperature for 30 minutes, and then holding it at a temperature between +3°C and -0°C above the maximum operating temperature for 30 minutes. This temperature cycle was performed 1,000 times. The maximum and minimum operating temperatures refer to the upper and lower limits of the operating temperature range of a multilayer ceramic capacitor, respectively. These temperatures vary depending on the product. In the thermal shock crack test shown in Table 1, the maximum operating temperature was 125°C and the minimum operating temperature was -55°C. However, the temperature settings in the thermal shock crack test are not limited to these. After the specified cycles were performed, cracks were confirmed by observing the polished cross section of the chip after the test.

[0078] The substrate bending crack test conforms to JIS C 5101. Specifically, the multilayer ceramic capacitor 1 is mounted on a substrate having a thickness of 1.6 mm. After that, the R1 jig base is bent 5 mm and held for 60 seconds.

[0079] In the thermal shock crack test and the substrate bending crack test, if a crack reached the effective portion 11 of the ceramic body 2, it was judged that a crack was present. This is because if a crack reaches the effective portion 11, the internal electrode layers may short-circuit, causing the multilayer ceramic capacitor 1 to fail.

[0080] The number of samples for each of the thermal shock crack test and the substrate bending crack test was 20.

[0081] The occurrence of cracks after the thermal shock crack test and the substrate bending crack test was confirmed by observing the LT cross section of the ceramic body 2 in a state where it was polished in the width direction W up to the center position in the width direction W. In addition, the average length of the cracks in the resin electrode 23 after the substrate bending crack test was determined by analyzing a scanning electron microscope image of the resin electrode 23 of the second terminal electrode 21.

[0082] As shown in Table 1, when the particle size of the filler 42 was 5.0 μm or more and the aspect ratio was 4.0 or more, no cracks occurred after the thermal shock crack test and the substrate bending crack test.

[0083] The filler 42 is preferably oriented as follows: That is, it is preferable that 70% or more of the filler 42 near the interface between the resin electrode 23 and the ceramic body 2 has an angle of 10° or less between the longitudinal direction 46 of the filler 42 and the interface with the ceramic body 2. This allows the destruction of the resin electrode 23 to progress more reliably.

[0084] Similarly, it is preferable that 70% or more of the filler 42 near the outer surface 27 of the resin electrode 23 have an angle of 10° or less between the longitudinal direction 46 of the filler 42 and the surface 27. This makes it possible to more reliably promote the destruction of the resin electrode 23.

[0085] Furthermore, it is preferable that the average length of cracks in the resin electrode 23 after the substrate bending crack test is 5 μm or more, which can more reliably prevent cracks from occurring in the ceramic body 2 .

[0086] Furthermore, as shown in Table 1, it is preferable that the degree of orientation of the filler 42 is 30 degrees or less and the interparticle distance of the filler 42 is 3 μm or less. In particular, it is preferable that the interparticle distance of the filler 42 in the direction perpendicular to the surface of the ceramic body is 3 μm or less.

[0087] When the orientation degree of all fillers 42 in the resin electrode 23 is 30 degrees or less and the inter-particle distance is 3 μm or less, cracks, i.e., fractures 50, tend to develop more easily in the resin electrode 23.

[0088] This is for the following reason. The resin electrode 23 is composed of a metal filler 42 and a resin 40. In such a resin electrode 23, the order of the locations where the fracture 50 is likely to progress is as follows: No. 1 is the interface between the resin 40 and the filler 42, No. 2 is within the resin 40, and No. 3 is within the filler 42. However, the fracture 50 almost never progresses within the filler 42. The fracture 50 mainly progresses at the interface between the resin 40 and the filler 42 and within the resin 40.

[0089] Therefore, if the proportion of the interface between the resin 40 and the filler 42 in the propagation distance of the fracture 50 is increased as much as possible, the fracture 50 will be more likely to propagate.

[0090] When the filler 42 is oriented in a certain direction, the fracture 50 tends to progress along the interface between the resin 40 and the filler 42. This is because the directions in which the interfaces between the resin 40 and the filler 42 extend tend to be aligned.

[0091] The smaller the degree of orientation of the filler 42 relative to the ceramic body 2, the more the filler 42 is oriented in a fixed direction. Therefore, when the degree of orientation is equal to or less than a certain angle, fracture 50 is more likely to occur.

[0092] Furthermore, the fracture 50 can be made to propagate more easily by minimizing the proportion of the fracture 50 within the resin 40 in the propagation distance of the fracture 50. In order to reduce the fracture 50 within the resin 40, it is important to reduce the distance between the fillers 42. Therefore, the fracture 50 is made to propagate more easily when the interparticle distance is equal to or less than a certain value.

[0093] A method for measuring the length and thickness of each part other than the above-mentioned measurement method will now be described. The multilayer ceramic capacitor 1 is polished to the center position in the width direction W. The LT cross section exposed by polishing is then observed using an optical microscope or the like. The length, thickness, etc. can be measured from the observed LT cross section.

[0094] A method for manufacturing the multilayer ceramic capacitor 1 will be described. A conductive paste for the dielectric sheets and the internal electrode layers is prepared. The conductive paste for the dielectric sheets and the internal electrode layers contains a binder and a solvent. The binder and the solvent may be a known organic binder and organic solvent, for example.

[0095] A conductive paste for the internal electrode layers is printed on the dielectric sheet in a predetermined pattern. The internal electrode layer pattern is formed by printing the conductive paste. The printing can be performed by, for example, screen printing or gravure printing.

[0096] A predetermined number of dielectric sheets for the outer layer portions are stacked. No internal electrode layer patterns are printed on the dielectric sheets for the outer layer portions. Dielectric sheets with internal electrode layer patterns printed on them are stacked in order on top of the stacked dielectric sheets. Furthermore, a predetermined number of dielectric sheets for the outer layer portions are stacked on top of those. A laminated sheet is produced by stacking these layers.

[0097] The laminated sheet is pressed in the height direction to produce a laminated block, which can be pressurized by isostatic pressing.

[0098] The laminated block is cut to a predetermined size. This cutting process cuts out laminated chips. When cutting, the corners and ridges of the laminated chips may be rounded. The rounding method can be barrel polishing.

[0099] The laminated chip is fired to produce a ceramic body. The firing temperature is preferably 900° C. or higher and 1110° C. or lower. The firing temperature can be changed depending on the materials of the dielectric and internal electrode layers.

[0100] Forming the terminal electrodes. First, a conductive paste that will become the base electrode 22 is applied to the two end surfaces of the ceramic body 2. The conductive paste contains glass, metal, etc. The conductive paste can be applied by a method such as dipping. After application, firing is performed to form the base electrode 22. The firing temperature is preferably 500°C or higher and 900°C or lower. The firing time is preferably 30 minutes or higher and 2 hours or lower.

[0101] A resin electrode 23 is formed on the base electrode 22. A conductive resin paste is prepared. The conductive resin paste contains a resin, a metal, and a solvent. The conductive resin paste is applied onto the base electrode 22. The application method can be dipping.

[0102] In the conductive resin paste, the average aspect ratio of the filler is set to 4 or more. The amount of filler added is set to an amount such that the volume ratio of the filler is 40 volume % or more. The viscosity of the conductive resin paste is preferably 1 to 50 Pa·s.

[0103] A method for forming the resin electrode 23 will be specifically described with reference to Fig. 8. Fig. 8 is a diagram showing the steps of forming the resin electrode 23. In (1), the thickness of the conductive resin paste 64 placed on the plate 60 is made uniform by moving the blade 61 in the negative direction of the X-axis.

[0104] The ceramic body 2 with the base electrode 22 formed thereon is defined as a chip 66. In (2), the chip 66 is immersed in the conductive resin paste 64. Specifically, the chip 66 is moved in the negative direction of the Y axis, and the coated surface 68 is pressed against the plate 60.

[0105] In step (3), the tip 66 is pulled up in the positive direction of the Y axis. When pulling up, the pulling speed is increased. The pulling speed is preferably 0.7 mm / s or more, and more preferably 1.0 mm / s or more.

[0106] In (4), the conductive resin paste 64 remaining on the plate 60 is removed using a squeegee 62. Specifically, while the squeegee 62 is in contact with the plate 60, the squeegee 62 is moved in the positive direction of the X axis.

[0107] In (5), the thickness of the conductive resin paste 64 newly placed on the plate 60 is made uniform by moving the blade 61 in the negative direction of the X-axis. The thickness of the conductive resin paste 64 after uniformization is made thinner than the thickness in (1). The thickness of the conductive resin paste 64 in (5) is preferably 50 μm or less, and more preferably 30 μm or less.

[0108] In step (6), scraping is performed. Specifically, the tip 66 is moved in the negative direction of the Y axis, and the coating surface 68 is pressed against the plate 60. Note that in step (4), the conductive resin paste 64 may be removed from the plate 60, and in step (6), the coating surface 68 may be pressed against a plate 60 on which the conductive resin paste 64 is not placed. In this case, step (5) can be omitted.

[0109] In step (7), the tip 66 is pulled up in the positive direction of the Y-axis. When pulling up, the pulling speed is increased. The pulling speed is preferably 0.7 mm / s or more, and more preferably 1.0 mm / s or more. This completes the application of the conductive resin paste 64.

[0110] After application, the resin is subjected to a heat treatment. The heat treatment involves drying the resin in a hot air oven at 150° C. to 180° C. for 10 minutes, and then curing the resin in an air atmosphere at 200° C. to 280° C. for 60 minutes. This thermal curing forms the resin electrode 23.

[0111] A nickel plating film 24 is formed on the surface of the resin electrode 23. Furthermore, a tin plating film 25 is formed on the surface of the nickel plating film 24. The nickel plating film 24 and the tin plating film 25 can be formed by a barrel plating method or the like. In this manner, the multilayer ceramic capacitor 1 is obtained.

[0112] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various changes and modifications are possible.

[0113] <1> A multilayer ceramic capacitor comprising: a ceramic body including a plurality of laminated dielectric layers and a plurality of laminated internal electrode layers, the ceramic body having first and second main surfaces opposing each other in a height direction, first and second side surfaces opposing each other in a width direction perpendicular to the height direction, and first and second end faces opposing each other in a length direction perpendicular to the height and width directions; and terminal electrodes provided on the ceramic body and connected to some of the internal electrode layers, the terminal electrodes including resin electrodes, and the resin electrodes including resin and a conductive filler, the average particle size of the filler being 5 μm or more, and the average aspect ratio of the filler being 4 or more.

[0114] <2> The multilayer ceramic capacitor according to <1>, wherein the filler has a degree of orientation of 30 degrees or less, and the filler has an interparticle distance of 3 μm or less.

[0115] <3> The multilayer ceramic capacitor according to <1> or <2>, wherein 70% or more of the filler in the resin electrode near the interface between the resin electrode and the ceramic body has an angle of 10° or less between the longitudinal direction of the filler and the interface.

[0116] <4> The multilayer ceramic capacitor according to any one of <1> to <3>, wherein 70% or more of the filler particles near the outer surface of the resin electrode have an angle of 10° or less between the longitudinal direction of the filler and the surface.

[0117] <5> The multilayer ceramic capacitor according to any one of <1> to <4>, wherein the average length of cracks in the resin electrode after a substrate bending crack test is 5 μm or more.

[0118] REFERENCE SIGNS LIST 10 First main surface side outer layer portion 11 Effective portion 12 Second main surface side outer layer portion 13 First end surface side outer layer portion 14 Lengthwise opposing portion 15 Second end surface side outer layer portion 16 First side surface side outer layer portion 17 Widthwise opposing portion 18 Second side surface side outer layer portion 20 First terminal electrode 21 Second terminal electrode 22 Base electrode 23 Resin electrode 24 Nickel plating film 25 Tin plating film 27 Surface 30 Outer layer dielectric layer 31 Inner layer dielectric layer 32 First internal electrode layer 33 Second internal electrode layer 34 First opposing electrode portion 35 Second opposing electrode portion 36 First lead electrode portion 37 Second lead electrode portion 60 Plate 66 Chip 68 Coating surface L Lengthwise direction T Height direction W Width direction

Claims

1. a ceramic body including a plurality of laminated dielectric layers and a plurality of internal electrode layers, the ceramic body having a first main surface and a second main surface opposing each other in a height direction, a first side surface and a second side surface opposing each other in a width direction perpendicular to the height direction, and a first end surface and a second end surface opposing each other in a length direction perpendicular to the height direction and the width direction; a terminal electrode provided on the ceramic body and connected to a part of the internal electrode layers, the terminal electrode includes a resin electrode, the resin electrode includes a resin and a conductive filler; The average particle size of the filler is 5 μm or more, The filler has an average aspect ratio of 4 or more, The orientation degree of the filler is 30 degrees or less, The interparticle distance of the filler is 3 um or less. Multilayer ceramic capacitor.

2. In the resin electrode, 70% or more of the filler particles in the vicinity of the interface between the resin electrode and the ceramic body have an angle of 10° or less between the longitudinal direction of the filler and the interface. The multilayer ceramic capacitor according to claim 1 .

3. 70% or more of the filler near the outer surface of the resin electrode has an angle between the longitudinal direction of the filler and the surface of 10° or less. The multilayer ceramic capacitor according to claim 1 .

4. 70% or more of the filler particles near the outer surface of the resin electrode have an angle of 10° or less between the longitudinal direction of the filler and the surface. The multilayer ceramic capacitor according to claim 2 .

5. The average length of cracks in the resin electrode after a substrate bending crack test is 5 μm or more. The multilayer ceramic capacitor according to claim 1 .