Multilayer ceramic capacitor and method of manufacturing same

Abstract

The invention provides a multilayer ceramic capacitor and a method of manufacturing the same. The multilayer ceramic capacitor includes: a capacitor body including a dielectric layer and an inner electrode layer; and an external electrode disposed on an outer surface of the capacitor body, the capacitor body includes an effective portion in which the dielectric layers and the inner electrode layers are alternately disposed, side edge portions disposed at two side end portions of the effective portion opposite to each other, and bonding portions disposed between the effective portion and the side edge portions, respectively. And at least one of the effective portion and the side edge portion includes a barium titanate-based main component including barium (Ba) and titanium (Ti), and gallium (Ga).

Description

Technical Field

[0001] The present disclosure relates to a multilayer ceramic capacitor and a method of manufacturing the same. Background Art

[0002] Electronic components using ceramic materials include capacitors, inductors, piezoelectric elements, varistors, thermistors, etc. Multilayer ceramic capacitors (MLCCs) among ceramic electronic components are used in various electronic devices due to their advantages of miniaturization, high capacity, and easy mounting.

[0003] For example, a multilayer ceramic capacitor (MLCC) can be mounted on a substrate of various electronic products such as imaging devices (such as liquid crystal displays (LCDs), plasma display panels (PDPs), organic light emitting diode (OLED) displays, etc.), computers, personal portable terminals, and smart phones, so that the multilayer ceramic capacitor (MLCC) is used as a chip capacitor that plays a role of charging or discharging therein.

[0004] On the other hand, a multilayer ceramic capacitor (MLCC) has the following internal structure: BaTiO 3 The dielectric layers and the inner electrode layers including Ni are alternately stacked, and the outer structure of the multilayer ceramic capacitor (MLCC) includes a certain thickness of BaTiO 3 The outer structure has problems such as cracks due to external stress and deterioration of electrical characteristics due to step differences generated in the portion without the inner electrode layer. Summary of the invention

[0005] Some embodiments of the present disclosure provide a multilayer ceramic capacitor having excellent moisture resistance reliability and excellent withstand voltage characteristics by improving density at ends of internal electrode layers.

[0006] Another embodiment provides a method of manufacturing a multilayer ceramic capacitor.

[0007] According to some embodiments, a multilayer ceramic capacitor includes: a capacitor body including a dielectric layer and an inner electrode layer; and an outer electrode disposed on an outer surface of the capacitor body. The capacitor body includes an effective portion where the dielectric layer and the inner electrode layer are alternately disposed, a side edge portion disposed on two side ends of the effective portion opposite to each other, and a bonding portion disposed between the effective portion and the side edge portion, respectively, and at least one of the effective portion and the side edge portion includes a barium titanate-based main component containing barium (Ba) and titanium (Ti) and gallium (Ga).

[0008] The barium titanate-based main component and gallium (Ga) may be included in the side edge portion.

[0009] If each of the side edge portions is substantially equally divided into two regions in the width direction, so that the region closer to the joining portion of the two regions is referred to as a first side edge portion, and the remaining region of the two regions is referred to as a second side edge portion, then gallium (Ga) may be included in the first side edge portion.

[0010] The first side margin portion may include gallium (Ga) in an amount within a range of greater than 0 parts by weight and less than or equal to 1.5 parts by weight based on 100 parts by weight of barium (Ba) in the first side margin portion.

[0011] Gallium (Ga) may be included in the first side margin portion and the second side margin portion, and a content of the gallium (Ga) included in the first side margin portion may be higher than a content of the gallium (Ga) included in the second side margin portion.

[0012] The barium titanate-based main component and gallium (Ga) may be included in the effective portion.

[0013] The effective portion may include a boundary adjacent region, which is defined as a region whose length from the boundary between the effective portion and the combining portion in the width direction of the capacitor body toward the effective portion corresponds to two to three times the width direction length of each of the side edge portions, and the boundary adjacent region of the effective portion may include gallium (Ga).

[0014] If the boundary adjacent area of ​​the effective portion is divided into two regions substantially equally in the width direction, and the region closer to the bonding portion of the two regions is referred to as a first effective portion, and the remaining region of the two regions is referred to as a second effective portion, gallium (Ga) may be included in the first effective portion and the second effective portion, and the content of gallium (Ga) in the first effective portion may be higher than the content of gallium (Ga) in the second effective portion.

[0015] Each of the side edge portion and the effective portion may include the barium titanate-based main component and gallium (Ga).

[0016] A content of gallium (Ga) included in the side margin portion may be higher than a content of gallium (Ga) included in the effective portion.

[0017] The bonding part may include a barium titanate-based compound including barium (Ba) and titanium (Ti), and gallium (Ga).

[0018] The bonding part may include gallium (Ga) in an amount ranging from 0.3 parts by weight to 1.5 parts by weight based on 100 parts by weight of barium (Ba) in the bonding part.

[0019] For a bonding surface between the effective part and the bonding part, a pore generation rate at an end of the inner electrode layer obtained by the following Equation 1 may be greater than 0% and less than or equal to 40%.

[0020] [Equation 1]

[0021] Hole generation rate at the end of the internal electrode layer=(the number of internal electrode layers having holes at the end of the internal electrode layer / the total number of the internal electrode layers)×100%.

[0022] According to some embodiments, a method for manufacturing a multilayer ceramic capacitor includes: preparing an edge sheet having a sticky surface by applying a coating composition including a barium titanate-based compound and gallium (Ga) onto at least one surface of the edge sheet; manufacturing a dielectric green sheet using a dielectric slurry and forming a conductive paste layer on the surface of the dielectric green sheet; manufacturing a dielectric green sheet stack by stacking dielectric green sheets on which the conductive paste layer is formed; cutting the dielectric green sheet stack to expose the conductive paste layer without retaining a region where the conductive paste layer is not formed; bonding the edge sheet having the sticky surface to the cut surface of the dielectric green sheet stack; manufacturing a capacitor body by firing the dielectric green sheet stack to which the edge sheet is bonded; and forming an external electrode on the surface of the capacitor body. The capacitor body includes an effective part in which dielectric layers and internal electrode layers are alternately arranged, side edge parts are arranged at two side ends of the effective part opposite to each other, and connecting parts are respectively arranged between the effective part and the side edge parts, and at least one of the effective part and the side edge parts includes a barium titanate-based main component containing barium (Ba) and titanium (Ti) and gallium (Ga).

[0023] The coating composition may include gallium (Ga) in an amount ranging from greater than 0 parts by mole to equal to or less than 6 parts by mole based on 100 parts by mole of the barium titanate-based compound.

[0024] Gallium (Ga) may be included in the coating composition in the form of a gallium-containing oxide, a gallium-containing nitride, a gallium-containing salt compound, or a combination thereof.

[0025] The coating composition may further include a binder.

[0026] The multilayer ceramic capacitor according to some embodiments may have excellent moisture resistance reliability and excellent withstand voltage characteristics by improving the density of the end portions of the internal electrode layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment.

[0028] Figure 2 It is along Figure 1A cross-sectional view of a multilayer ceramic capacitor cut along line I-I'.

[0029] Figure 3 It is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor cut along line II-II'.

[0030] Figure 4 is a schematic diagram illustrating a process of forming a side margin portion in a method of manufacturing a multilayer ceramic capacitor according to an embodiment.

[0031] Figure 5A is a graph showing the content of gallium (Ga) at various locations in the multilayer ceramic capacitor according to Example 1.

[0032] Figure 5B is a graph showing the content of gallium (Ga) at various positions in the multilayer ceramic capacitor according to Example 2.

[0033] Fig. 6A is a SEM image showing that holes are generated at the end portions of the internal electrode layers in the multilayer ceramic capacitor according to Example 1.

[0034] Figure 6B is a SEM image showing that holes are generated at the end portions of the internal electrode layers in the multilayer ceramic capacitor according to Example 2.

[0035] Figure 6C is a SEM image showing that holes are generated at the end portions of the internal electrode layers in the multilayer ceramic capacitor according to Comparative Example 1.

[0036] Fig. 7A is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Example 1.

[0037] Figure 7B is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Example 2.

[0038] Figure 7C is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Comparative Example 1. DETAILED DESCRIPTION

[0039] The present disclosure will be described more fully hereinafter with reference to the accompanying drawings in which embodiments of the present disclosure are shown. In order to clearly describe the present disclosure, parts or portions not related to the description are omitted, and the same or similar constituent elements are represented by the same reference numerals throughout the specification. In addition, in the accompanying drawings, some constituent elements are enlarged, omitted or schematically shown, and the size of each constituent element does not fully reflect the actual size.

[0040] The accompanying drawings are provided only to make the embodiments disclosed in this specification easier to understand and should not be interpreted as limiting the spirit disclosed in this specification. It should be understood that the present disclosure includes all modifications, equivalents, and alternatives without departing from the scope and spirit of the present disclosure.

[0041] Terms including ordinal numbers such as first, second, etc. may be used to describe various constituent elements, but the constituent elements are not limited by the terms. These terms are used only for the purpose of distinguishing one constituent element from another constituent element.

[0042] It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "over" another element, it may be directly on the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements. In addition, in the specification, the words "on..." or "above..." mean being disposed on or below a target portion, and do not necessarily mean being disposed on the upper side of the target portion based on the direction of gravity.

[0043] In this specification, terms such as "include" or "have" are intended to indicate the presence of the features, quantities, steps, operations, constituent elements, components, or combinations thereof described in the specification, and should be understood as not excluding the possibility of the presence or addition of one or more other features, quantities, steps, operations, constituent elements, components, or combinations thereof. In addition, unless explicitly described to the contrary, the word "include" and variations such as "comprises" or "have" will be understood to imply the inclusion of the elements but not the exclusion of any other elements.

[0044] Furthermore, throughout the specification, the phrase “on a plane” means observing a target portion from the top, and the phrase “on a cross section” means observing a cross section formed by vertically cutting the target portion from the side.

[0045] Throughout the specification, when one part is described as being “connected” to another part, the one part may be “directly connected” to the other part, may be “connected” to the other part through a third part, or may be physically connected to the other part or electrically connected to the other part, and may be represented by different titles according to position or function, but corresponding parts that are basically integrated into one body may be connected to each other.

[0046] As used herein, the term "substantially" means: a small, insignificant range of variation relative to absolute or perfect conditions, dimensions, measurements, results, etc. that would be expected by a person skilled in the art but would not significantly affect the overall performance and allow for variations. When "substantially" is used for a quantity or parameter or property that can be expressed as a number, "substantially" means that the variation range is within 10%.

[0047] As used herein, the term "about" means approximately. Typically, the term "about" is used herein to define a numerical value as being within a 10% variation range above or below the numerical value. In one aspect, the term "about" means within ±20% of the numerical value of the number with which it is used.

[0048] In the following, reference will be made to Figures 1 to 3 A multilayer ceramic capacitor according to an embodiment is described.

[0049] Figure 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment, Figure 2 It is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor cut along line I-I', and Figure 3 It is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor cut along line II-II'.

[0050] Figures 1 to 3 The L-axis direction, W-axis direction, and T-axis direction shown in represent the length direction, width direction, and thickness direction of the capacitor body 110, respectively. Here, the thickness direction (T-axis direction) may be a direction perpendicular to the wide surface (main surface) of the constituent element having a sheet shape. For example, the thickness direction (T-axis direction) may be used as the same concept as the stacking direction of the stacked dielectric layer 111. The length direction (L-axis direction) may be a direction extending parallel to the wide surface (main surface) of the constituent element having a sheet shape and substantially perpendicular to the thickness direction (T-axis direction). For example, the length direction (L-axis direction) may be a direction in which the first external electrode 131 and the second external electrode 132 are arranged at both surfaces. The width direction (W-axis direction) is a direction extending parallel to the wide surface (main surface) of the constituent element having a sheet shape and substantially perpendicular to the thickness direction (T-axis direction) and the length direction (L-axis direction), and the length of the constituent element having a sheet shape in the length direction (L-axis direction) may be greater than the length of the constituent element having a sheet shape in the width direction (W-axis direction).

[0051] Reference Figures 1 to 3 , the multilayer ceramic capacitor 100 according to some embodiments of the present disclosure includes a capacitor body 110 and external electrodes 131 and 132 disposed outside the capacitor body 110. The external electrodes 131 and 132 may include a first external electrode 131 and a second external electrode 132 disposed at both ends of the capacitor body 110 opposite to each other in the length direction (L-axis direction).

[0052] For example, the capacitor body 110 may have an approximately hexahedral shape.

[0053] For the convenience of describing this embodiment, two surfaces of the capacitor body 110 that are opposite to each other in the thickness direction (T-axis direction) are defined as a first surface and a second surface, two surfaces connected to the first surface and the second surface and opposite to each other in the length direction (L-axis direction) are defined as a third surface and a fourth surface, and two surfaces connected to the first surface and the second surface and the third surface and the fourth surface and opposite to each other in the width direction (W-axis direction) are defined as a fifth surface and a sixth surface.

[0054] For example, the first surface as the lower surface may be a mounting surface. In addition, the first to sixth surfaces may be flat, but the present disclosure is not limited thereto. For example, each of the first to sixth surfaces may be a curved surface having a convex central portion, and the corners as the boundaries of the surfaces may be rounded.

[0055] The shape and size of the capacitor body 110 and the number of stacked dielectric layers 111 are not limited to the shape and size of the capacitor body 110 and the number of dielectric layers 111 shown in the drawings of the present disclosure.

[0056] The capacitor body 110 includes a plurality of dielectric layers 111 and internal electrode layers (or referred to as internal electrodes) 121 and 122. Specifically, the capacitor body 110 includes a plurality of dielectric layers 111 and first and second internal electrodes 121 and 122, and the first and second internal electrodes 121 and 122 are alternately arranged in the thickness direction (T-axis direction) and the dielectric layer 111 is interposed between the first and second internal electrodes 121 and 122.

[0057] In this case, the dielectric layers 111 of the capacitor body 110 adjacent to each other may be integrated to such an extent that it is difficult to check a boundary therebetween without using a scanning electron microscope (SEM).

[0058] The capacitor body 110 includes an effective part 10 where dielectric layers and internal electrode layers are alternately arranged, side edge parts 20 and 20 ′ arranged at both side ends of the effective part 10 opposite to each other, and coupling parts 30 and 30 ′ respectively arranged between the effective part 10 and the side edge parts 20 and 20 ′.

[0059] The effective portion 10 is a portion that contributes to forming the capacitance of the multilayer ceramic capacitor 100. For example, the effective portion 10 may be a region where the first and second internal electrodes 121 and 122 stacked in the thickness direction (T-axis direction) overlap.

[0060] The side edge portions 20 and 20' may be disposed at two side ends of the effective portion 10 opposite to each other, may be referred to as side surface covering portions, and may be respectively disposed at two side ends of the effective portion 10 opposite to each other in the width direction (W-axis direction) (i.e., close to the fifth surface and the sixth surface of the capacitor body 110).

[0061] The capacitor body 110 may further include a cover portion.

[0062] The covering portion may be an edge portion in the thickness direction and may be respectively disposed on the first surface and the second surface in the thickness direction (T-axis direction) of the effective portion 10. The covering portion may be a single dielectric layer 111 or two or more dielectric layers 111 stacked on the upper and lower surfaces of the effective portion 10.

[0063] The side margin parts 20 and 20 ′ and the covering part may serve to prevent damage to the first and second internal electrodes 121 and 122 due to physical stress or chemical stress.

[0064] The coupling parts 30 and 30 ′ may be respectively disposed between the effective part 10 and the side edge parts 20 and 20 ′ for coupling the side edge parts 20 and 20 ′ to the effective part 10 .

[0065] At least one of the effective portion 10 and the side edge portions 20 and 20 ′ may include a barium titanate-based main component including barium (Ba) and titanium (Ti), and gallium (Ga).

[0066] The barium titanate-based main component may be a dielectric matrix material, may have a high dielectric constant, and may contribute to forming the dielectric constant of the multilayer ceramic capacitor 100 .

[0067] For example, the barium titanate-based main component may include BaTiO 3 、Ba(Ti,Zr)O 3 、Ba(Ti,Sn)O 3 、(Ba,Ca)TiO 3 、(Ba,Ca)(Ti,Zr)O 3 、(Ba,Ca)(Ti,Sn)O 3 、(Ba,Sr)TiO 3 、(Ba,Sr)(Ti,Zr)O 3 、(Ba,Sr)(Ti,Sn)O 3 or a combination thereof.

[0068] Gallium (Ga) included in at least one of the effective portion 10 and the side edge portions 20 and 20' may be derived from a gallium (Ga) component added when forming the bonding portions 30 and 30'. That is, in the process of manufacturing the capacitor body 110, gallium (Ga) may be a component included in a coating composition for bonding an edge sheet forming the side edge portion and a dielectric green sheet laminate forming the effective portion. After firing the dielectric green sheet laminate bonded with the edge sheet, gallium (Ga) may diffuse into at least one of the effective portion 10 and the side edge portions 20 and 20'.

[0069] If at least one of the active portion 10 and the side edge portions 20 and 20' includes a gallium (Ga) component diffused from a component for forming the bonding portions 30 and 30', the density of the end of the internal electrode layer can be improved, thereby improving moisture resistance reliability and withstand voltage characteristics of the multilayer ceramic capacitor.

[0070] Unlike the effective part, the side edge part of a typical multilayer ceramic capacitor may not have an inner electrode layer, so that the step difference is generated as much as the unprinted space. The phenomenon of generating the step difference may cause various problems (such as cracks due to external stress, degradation of electrical characteristics, etc.). According to some embodiments, a multilayer ceramic capacitor can be manufactured by applying an edge forming (MF) method. Specifically, the dielectric green sheet stack is cut to expose the conductive paste layer without retaining the state of the area where the conductive paste layer is not coated as the edge area, and then the side edge part is formed by bonding the edge sheet to the cut surface of the dielectric green sheet stack. In the MF method, if gallium (Ga) is included in the coating composition used as a binder when the edge sheet is attached to the cut surface, then because gallium (Ga) diffusion occurs after the edge sheet attached to the cut surface is fired, the effective part 10 and at least one of the side edge parts 20 and 20' may include gallium (Ga). Therefore, the adhesion of the bonding surface can be excellent, thereby suppressing the occurrence of delamination defects, and by fully ensuring the density of the bonding surface after firing, the moisture resistance reliability can be improved.

[0071] Specifically, a barium titanate-based main component and gallium (Ga) may be included in at least one of the side edge portions 20 and 20', or a barium titanate-based main component and gallium (Ga) may be included in the effective portion 10. In addition, a barium titanate-based main component and gallium (Ga) may be included in at least one of the side edge portions 20 and 20' and the effective portion 10. This can be confirmed by scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS) analysis.

[0072] SEM-EDS analysis can be performed by the following method. First, a cross-sectional sample can be obtained: after the multilayer ceramic capacitor 100 is placed in an epoxy resin mixture (or epoxy resin mixture) and the placed multilayer ceramic capacitor 100 is cured, the surface (WT surface) in the W-axis direction and the T-axis direction of the capacitor body 110 is polished to the 1 / 2 point in the L-axis direction, and the polished capacitor body is kept in a vacuum atmosphere chamber to observe the effective portion (where the dielectric layer 111 and each of the internal electrode layers 121 and 122 are stacked on each other) and the side edge portion. Next, the cross-sectional sample with the WT surface can be divided into two halves in the width direction (W-axis direction) so that the side edge portion and the effective portion on one side can be measured using a scanning electron microscope (SEM). For example, the SEM may be a VeriosG4 product from Thermo Fisher Scientific Inc., the measurement conditions may be 10 kV and 0.2 nA, the analysis magnification may be 10 k times, and 10 or more layers may be measured in the dielectric layer 111 and the inner electrode layers 121 and 122. Subsequently, an EDS analysis may be performed on the obtained SEM image of the cross-sectional sample, so that it may be checked whether gallium (Ga) exists in at least one of the effective portion and the side edge portion.

[0073] According to some embodiments, a barium titanate-based main component and gallium (Ga) may be included in the side margin parts 20 and 20 ′. At least one of the side margin parts 20 and 20 ′ may include a barium titanate-based main component and gallium (Ga).

[0074] In addition, each of the side edge portions 20 and 20' may be substantially equally divided into two regions in the width direction, and the region closer to the bonding portion 30 and 30' of the two regions is referred to as the first side edge portion 21 and 21', and the remaining region of the two regions is referred to as the second side edge portion 22 and 22'. In this case, gallium (Ga) may be included in at least one of the first side edge portions 21 and 21'.

[0075] Specifically, the content of gallium (Ga) included in at least one of the first side edge portions 21 and 21' may be in a range of greater than 0 parts by weight and less than or equal to 1.5 parts by weight relative to 100 parts by weight of barium (Ba) in at least one of the first side edge portions 21 and 21'. For example, the content of gallium (Ga) included in at least one of the first side edge portions 21 and 21' may be in a range of 0.1 parts by weight to 1.3 parts by weight or in a range of 0.3 parts by weight to 1.2 parts by weight relative to 100 parts by weight of (Ba) in at least one of the first side edge portions 21 and 21'. If the gallium (Ga) included in the first side edge portions 21 and 21' is within the content range, the density of the end of the inner electrode layer can be improved, thereby improving the moisture resistance reliability and voltage resistance characteristics of the multilayer ceramic capacitor.

[0076] The content of gallium (Ga) in the side edge portion 20 or 20' can be confirmed by SEM-EDS analysis. Specifically, if the side edge portion is divided into two regions in the width direction in the SEM image of the cross-sectional sample obtained by the above method, so that the region closer to the bonding portion of the two regions is called the first side edge portion, and the remaining region of the two regions is called the second side edge portion, the content of gallium (Ga) can be measured at at least one point (for example, 1 point to 10 points or 1 point to 5 points) in each of the first side edge portion and the second side edge portion, so as to obtain an average value of the measured values.

[0077] In addition, gallium (Ga) may be included in at least one of the first side edge portions 21 and 21' and corresponding at least one of the second side edge portions 22 and 22'. In this case, the content of gallium (Ga) included in the first side edge portions 21 and 21' may be higher than the content of gallium (Ga) included in the second side edge portions 22 and 22'. If the content of gallium (Ga) included in the first side edge portions 21 and 21' closer to the effective portion 10 is higher than the content of gallium (Ga) included in the second side edge portions 22 and 22', respectively, the density of the end portion of the inner electrode layer may be improved, so that the moisture resistance reliability and voltage resistance characteristics of the multilayer ceramic capacitor are improved.

[0078] In some embodiments, the effective portion 10 may include a barium titanate-based main component and gallium (Ga).

[0079] The effective portion 10 may include boundary adjacent regions 15 and 15', which are defined as regions whose lengths in the width direction from the boundary between the effective portion 10 and each of the bonding portions 30 and 30' toward the effective portion 10 correspond to two to three times the width direction length of each of the side edge portions 20 and 20', respectively. Specifically, gallium (Ga) may be included in at least one of the boundary adjacent regions 15 and 15' of the effective portion 10.

[0080] Each of the boundary adjacent regions 15 and 15' of the effective part 10 may be substantially equally divided into two regions in the width direction, and the region closer to the bonding parts 30 and 30' of the two regions is referred to as the first effective part 16 and 16', and the remaining region of the two regions is referred to as the second effective part 17 and 17'. In this case, gallium (Ga) may be included in the first effective part 16 and 16' and the second effective part 17 and 17'.

[0081] Specifically, the content of gallium (Ga) included in the first effective parts 16 and 16' may be higher than the content of gallium (Ga) included in the second effective parts 17 and 17', respectively. If a higher content of gallium (Ga) is included in the first effective parts 16 and 16' closer to the first side edge parts 21 and 21' in the boundary adjacent regions 15 and 15' of the effective part 10, the density of the end of the inner electrode layer can be improved, so that the moisture resistance reliability and the withstand voltage characteristics of the multilayer ceramic capacitor are improved.

[0082] The content of gallium (Ga) in the effective part 10 can be confirmed by SEM-EDS analysis. Specifically, if in the SEM image of the cross-sectional sample obtained by the above method, the effective part includes a boundary adjacent region (defined as a region whose length from the boundary between the effective part and each bonding part in the width direction toward the effective part 10 corresponds to two to three times the width direction length of each side edge part, respectively), and the boundary adjacent region of the effective part is divided into two regions in the width direction, so that the region closer to the bonding parts 30 and 30' of the two regions is called the first effective part 16 and 16', and the remaining region of the two regions is called the second effective part 17 and 17', then the gallium (Ga) content can be measured at at least one point (for example, 1 point to 10 points or 1 point to 5 points) in each of the first effective part and the second effective part to obtain an average value of the measured values.

[0083] In some embodiments, a barium titanate-based main component and gallium (Ga) may be included in at least one of the side margin parts 20 and 20 ′ and the effective part 10 .

[0084] Specifically, the content of gallium (Ga) included in the side margin parts 20 and 20' may be higher than the content of gallium (Ga) included in the effective part 10. If a higher content of gallium (Ga) is included in the side margin parts 20 and 20', the multilayer ceramic capacitor may have excellent moisture resistance reliability and excellent withstand voltage characteristics by improving the density of the end of the inner electrode layer.

[0085] For example, the content of gallium (Ga) included in at least one of the first side edge portions 21 or 21' may be higher than the content of gallium (Ga) included in at least one of the second side edge portions 22 or 22', respectively, the content of gallium (Ga) included in the first effective portions 16 and 16' may be lower than the content of gallium (Ga) included in the second side edge portions 22 and 22', and the content of gallium (Ga) included in the second effective portions 17 and 17' may be lower than the content of gallium (Ga) included in the first effective portions 16 and 16'.

[0086] According to an embodiment, at least one of the bonding parts 30 and 30 ′ may include a barium titanate-based compound including barium (Ba) and titanium (Ti), and gallium (Ga).

[0087] For example, the barium titanate-based compound may include BaTiO 3 、Ba(Ti,Zr)O 3 、Ba(Ti,Sn)O 3 、(Ba,Ca)TiO 3 、(Ba,Ca)(Ti,Zr)O 3 、(Ba,Ca)(Ti,Sn)O 3 、(Ba,Sr)TiO 3 、(Ba,Sr)(Ti,Zr)O 3 、(Ba,Sr)(Ti,Sn)O 3 or a combination thereof.

[0088] Gallium (Ga) included in the bonding parts 30 and 30 ′ may be derived from a gallium (Ga) component added in order to form the bonding parts 30 and 30 ′.

[0089] For example, based on 100 parts by weight of barium (Ba) in the bonding parts 30 and 30', the content of gallium (Ga) in the bonding parts 30 and 30' may be in the range of 0.3 parts by weight to 1.5 parts by weight or in the range of 0.5 parts by weight to 1.2 parts by weight. If gallium (Ga) included in the bonding parts 30 and 30' is within the content range, the multilayer ceramic capacitor may have excellent moisture resistance reliability and excellent withstand voltage characteristics by improving the density of the end of the inner electrode layer.

[0090] The content of gallium (Ga) in the bonding parts 30 and 30' can be confirmed by SEM-EDS analysis. Specifically, in the SEM image of the cross-sectional sample obtained by the above method, the content of gallium (Ga) can be measured at at least one point (e.g., 1 point to 10 points or 1 point to 5 points) in the bonding part to obtain an average value of the measured values.

[0091] The bonding parts 30 and 30' may be formed of a coating composition for bonding an edge sheet forming a side edge part and a dielectric green sheet laminate forming an effective part. A detailed description of the coating composition will be provided later in the description of a method of manufacturing a multilayer ceramic capacitor.

[0092] According to some embodiments, for example, for the bonding surface between the effective part 10 and each of the bonding parts 30 and 30', the hole generation rate at the end of each of the inner electrode layers 121 and 122 may be greater than 0% and less than or equal to 40% or in the range of 1% to 35%. The fact that the hole generation rate at the end of the inner electrode layer is within the range may mean that the density of the end of the inner electrode layer at the bonding part of the bonding side edge part is excellent. Therefore, moisture resistance reliability and voltage resistance characteristics can be improved.

[0093] The hole generation rate at the end of the inner electrode layer can be measured by the following method. A cross-sectional sample can be obtained: after the multilayer ceramic capacitor 100 is placed in an epoxy resin mixture (or epoxy resin mixture) and the placed multilayer ceramic capacitor 100 is cured, the surface (WT surface) in the W-axis direction and the T-axis direction of the capacitor body 110 is polished to the 1 / 2 point in the L-axis direction, and the polished capacitor body is kept in a vacuum atmosphere chamber to observe the effective part (where the dielectric layer 111 and each of the inner electrode layers 121 and 122 are stacked on each other) and the side edge part. Next, the cross-sectional sample with the WT surface can be divided into two halves in the width direction (W-axis direction) so that the side edge part and the effective part on one side can be measured using a scanning electron microscope (SEM). Therefore, the end of the inner electrode layer can be clearly seen. For example, the SEM can be a Verios G4 product from Thermofisher Scientific Inc., the measurement conditions can be 2 kV and 0.2 nA, the analysis magnification can be 10k times, and 10 or more layers (for example, 20 to 100 layers or 20 to 50 layers) in the dielectric layer 111 and the internal electrode layers 121 and 122 can be measured.

[0094] Therefore, the pore generation rate measured at the end of the inner electrode layer may be calculated by Equation 1 below.

[0095] [Equation 1]

[0096] Hole generation rate at the end of the internal electrode layer = (number of internal electrode layers having holes at their end / total number of internal electrode layers) × 100%

[0097] For example, the average thickness (average length in the T-axis direction) of the dielectric layer 111 may be in the range of about 2.0 μm to about 8.0 μm or in the range of about 2.4 μm to about 7.8 μm. If the average thickness of the dielectric layer 111 is within the range, the reliability of the multilayer ceramic capacitor is excellent.

[0098] The average thickness of the dielectric layer 111 can be measured by analyzing a cross-sectional sample obtained by the following method using a scanning electron microscope (SEM): the multilayer ceramic capacitor 100 is placed in an epoxy resin mixture (or epoxy resin mixture), the placed multilayer ceramic capacitor 100 is cured, the cured multilayer ceramic capacitor is polished, and then the polished multilayer ceramic capacitor is ion milled. For example, the SEM can be a VeriosG4 product from Thermo Fisher Scientific Inc., the measurement conditions can be 10kV and 0.2nA, the analysis magnification can be 100 times, and one or more layers (for example, 3 or more layers, 5 or more layers, or 10 or more layers) of the dielectric layer 111 can be measured. In the scanning electron microscope (SEM) image, the center point of the dielectric layer 111 in the length direction (L axis direction) or the width direction (W axis direction) can be used as a reference point. The average thickness of the dielectric layer 111 can be the arithmetic mean of the thickness of the dielectric layer 111 at ten points spaced apart from the reference point. The intervals of the ten points may be adjusted according to the scale of a scanning electron microscope (SEM) image. For example, the intervals of the ten points may be 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm. In this case, all ten points must be disposed within the dielectric layer 111. If all ten points are not disposed within the dielectric layer 111, the positions of the reference points may be changed, or the intervals between the ten points may be adjusted.

[0099] The first inner electrode 121 and the second inner electrode 122 may be electrodes having different polarities, the first inner electrode 121 and the second inner electrode 122 may be alternately arranged to be opposite to each other along the T-axis direction, and the dielectric layer 111 is interposed between the first inner electrode 121 and the second inner electrode 122, and one end of each of the first inner electrode 121 and the second inner electrode 122 may be exposed through one of the third surface and the fourth surface of the capacitor body 110.

[0100] The first and second internal electrodes 121 and 122 may be electrically insulated from each other by a dielectric layer 111 disposed therebetween.

[0101] Ends of the first and second internal electrodes 121 and 122 may be alternately exposed through the third and fourth surfaces of the capacitor body 110 and may be electrically connected to the first and second external electrodes 131 and 132 , respectively.

[0102] Each of the first and second internal electrodes 121 and 122 may include a conductive metal, and for example, each of the first and second internal electrodes 121 and 122 may include a metal such as Ni, Cu, Ag, Pd, Au, etc., or an alloy thereof (eg, Ag—Pd alloy).

[0103] In addition, each of the first and second internal electrodes 121 and 122 may include dielectric particles having the same composition as that of the ceramic material included in the dielectric layer 111 .

[0104] Each of the first and second internal electrodes 121 and 122 may be formed using a conductive paste including a conductive metal. A printing method of the conductive paste may be a screen printing method or a gravure printing method.

[0105] The average thickness of each of the first and second internal electrodes 121 and 122 may be about 0.1 μm to about 2 μm. The average thickness of each of the first and second internal electrodes 121 and 122 may be measured by scanning electron microscope (SEM) analysis. Here, since the scanning electron microscope (SEM) analysis is the same as the above-mentioned method of measuring the average thickness of the dielectric layer 111, the description thereof is omitted.

[0106] The capacitor body 110 may be formed by firing a laminated body in which a plurality of dielectric layers 111 and internal electrode layers 121 and 122 are laminated. A detailed manufacturing method of the capacitor body 110 according to the embodiment will be described later.

[0107] The first and second external electrodes 131 and 132 may be supplied with voltages having different polarities and may be electrically connected to exposed portions of the first and second internal electrodes 121 and 122 , respectively.

[0108] If a predetermined voltage is applied to the first and second external electrodes 131 and 132, charges are accumulated between the first and second internal electrodes 121 and 122 facing each other. In this case, the capacitance of the multilayer ceramic capacitor 100 is proportional to the overlapped area of ​​the first and second internal electrodes 121 and 122 overlapping each other in the T-axis direction in the effective portion.

[0109] The first outer electrode 131 may include: a first connecting portion, which is arranged on the third surface of the capacitor body 110 to be connected to the first inner electrode 121; and a first band portion, which is arranged at a corner where the third surface of the capacitor body 110 intersects with the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110. The second outer electrode 132 may include: a second connecting portion, which is arranged on the fourth surface of the capacitor body 110 to be connected to the second inner electrode 122; and a second band portion, which is arranged at a corner where the fourth surface of the capacitor body 110 intersects with the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110.

[0110] The first and second band portions may also extend from the first and second connecting portions, respectively, to a portion of the first and second surfaces and / or a portion of the fifth and sixth surfaces of the capacitor body 110. The first and second band portions may be used to increase the adhesion strength of the first and second external electrodes 131 and 132 to the capacitor body 110.

[0111] Each of the first and second external electrodes 131 and 132 may include a sintered metal layer contacting the capacitor body 110 , a conductive resin layer disposed to cover the sintered metal layer, and a plated layer disposed to cover the conductive resin layer.

[0112] The sintered metal layer may include conductive metal and glass.

[0113] The conductive metal may include at least one selected from the group consisting of copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb) and alloys thereof, and may include copper (Cu) or a copper (Cu) alloy, for example. If the conductive metal includes copper, the content of the metal other than copper included may be 5 parts by mole or less relative to 100 parts by mole of copper.

[0114] The glass may include a composition of mixed oxides, and for example, the composition may include one or more selected from the group consisting of silicon oxide, boron oxide, aluminum oxide, transition metal oxides, alkali metal oxides, and alkaline earth metal oxides. The transition metal may include at least one selected from the group consisting of zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni), the alkali metal may be selected from the group consisting of lithium (Li), sodium (Na), and potassium (K), and the alkaline earth metal may be one or more selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0115] In some embodiments, the conductive resin layer may be formed on the sintered metal layer, and, for example, may be formed to completely cover the sintered metal layer. In some embodiments, the first and second external electrodes 131 and 132 may not include the sintered metal layer, and in this case, the conductive resin layer may directly contact the capacitor body 110.

[0116] The conductive resin layer may extend to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110, and the length of the region (i.e., the band portion) of the conductive resin layer extending to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110 may be greater than the length of the region (i.e., the band portion) of the sintered metal layer extending to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110. In other words, the conductive resin layer is formed on the sintered metal layer and may be formed to completely cover the sintered metal layer.

[0117] The conductive resin layer includes resin and conductive metal.

[0118] The resin included in the conductive resin layer is not particularly limited as long as it has bonding and impact absorption properties and can be mixed with the conductive metal powder to form a paste, and may include, for example, phenolic resin, acrylic resin, silicone resin, epoxy resin, or polyimide resin.

[0119] The conductive metal included in the conductive resin layer serves to be electrically connected to the first and second internal electrodes 121 and 122 or the sintered metal layer.

[0120] The conductive metal included in the conductive resin layer may have a spherical shape, a flake shape, or a combination thereof. In other words, the conductive metal may be made into only a flake shape, may be made into only a spherical shape, or may have a mixture of a flake shape and a spherical shape.

[0121] Here, the spherical shape may include a shape that is not a completely spherical shape, and may include, for example, a shape in which the ratio of the length of the major axis to the minor axis (major axis / minor axis) is 1.45 or less. The powder having a flake shape refers to a powder having a flat and elongated shape, and the flake shape is not particularly limited, but, for example, the flake shape may include a shape in which the ratio of the length of the major axis to the minor axis (major axis / minor axis) is 1.95 or more.

[0122] Each of the first and second external electrodes 131 and 132 may further include a plating layer disposed outside the conductive resin layer.

[0123] The plating layer may include at least one selected from the group consisting of nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb) and alloys thereof. For example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, and may have a form in which a nickel (Ni) plating layer and a tin (Sn) plating layer are stacked in sequence, or may have a form in which a tin (Sn) plating layer, a nickel (Ni) plating layer and a tin (Sn) plating layer are stacked in sequence. In addition, the plating layer may include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0124] The plating layer may improve the mountability of the multilayer ceramic capacitor 100 with a substrate, structural reliability, durability to the outside, heat resistance, or equivalent series resistance (ESR).

[0125] Hereinafter, a method of manufacturing the multilayer ceramic capacitor 100 according to an embodiment will be described.

[0126] The multilayer ceramic capacitor 100 according to the present embodiment can be manufactured by the following steps: a step of preparing an edge sheet having a sticky surface by applying a coating composition including a barium titanate-based compound and gallium (Ga) to at least one surface of the edge sheet; a step of manufacturing a dielectric green sheet using a dielectric slurry and forming a conductive paste layer on the surface of the dielectric green sheet; a step of manufacturing a dielectric green sheet stack by stacking dielectric green sheets on which the conductive paste layer is formed; a step of cutting the dielectric green sheet stack in a state in which the conductive paste layer is exposed without leaving a region in which the conductive paste layer is not formed; a step of bonding an edge sheet having a sticky surface to a cut surface of the cut dielectric green sheet stack; a step of manufacturing a capacitor body by firing the dielectric green sheet stack to which the edge sheet is bonded; and a step of forming an external electrode on the surface of the capacitor body.

[0127] First, an edge sheet having an adhesive surface is prepared by applying a coating composition to at least one surface of the edge sheet.

[0128] The coating composition includes a barium titanate-based compound and gallium (Ga).

[0129] The barium titanate-based compound may include barium (Ba) and titanium (Ti), and for example, the barium titanate-based compound may include BaTiO 3 、Ba(Ti,Zr)O 3 、Ba(Ti,Sn)O 3 、(Ba,Ca)TiO 3 、(Ba,Ca)(Ti,Zr)O 3 、(Ba,Ca)(Ti,Sn)O 3 、(Ba,Sr)TiO 3 、(Ba,Sr)(Ti,Zr)O 3 、(Ba,Sr)(Ti,Sn)O 3 or a combination thereof.

[0130] Gallium (Ga) can be included in the coating composition in the form of a Ga-containing oxide, a Ga-containing nitride, a Ga-containing salt compound, or a combination thereof. For example, gallium (Ga) can be a Ga-containing oxide (e.g., gallium oxide (Ga 2 O 3 )). In addition, for example, fine particles of gallium (Ga) of 50 nm or less may be used.

[0131] Based on 100 molar parts of the barium titanate-based compound, the content of gallium (Ga) included in the coating composition may be in a range of greater than 0 molar parts and less than or equal to 6 molar parts. For example, based on 100 molar parts of the barium titanate-based compound, the content of gallium (Ga) included in the coating composition may be in a range of 0.5 molar parts to 5 molar parts or in a range of 1 molar parts to 4 molar parts. If the gallium (Ga) included in the coating composition is within the content range, the density of the end of the inner electrode layer can be improved, thereby manufacturing a multilayer ceramic capacitor with excellent moisture resistance reliability and excellent withstand voltage characteristics.

[0132] The coating composition may also include a binder to provide adhesion.

[0133] For example, the binder may include acrylic resin, polyvinyl butyl resin, polyvinyl acetal resin, ethyl cellulose resin, and the like.

[0134] The content of the included binder may be in the range of 5% to 60% by weight based on the total amount of the coating composition. For example, the content of the included binder may be in the range of 40% to 60% by weight based on the total amount of the coating composition. If the included binder is within the content range, the dispersibility of the coating composition may be excellent, and sufficient adhesion may be provided to the bonding surface, thereby suppressing the occurrence of delamination defects, and a multilayer ceramic capacitor having excellent moisture resistance reliability may be obtained by fully ensuring the density of the bonding surface after firing.

[0135] The edge sheet may be formed into the side edge portions 20 and 20' after firing, and may include a barium titanate-based main component. Since the barium titanate-based main component is the same as the barium titanate-based main component included in at least one of the side edge portions 20 and 20' and the effective portion 10, its description is omitted.

[0136] In the next step, a dielectric green sheet is manufactured using the dielectric slurry, and a conductive paste layer is formed on the surface of the dielectric green sheet.

[0137] The dielectric slurry may be prepared by selectively mixing a barium titanate-based main component powder and a sub-component powder.

[0138] Since the composition of the barium titanate-based main component powder is the same as the composition of the barium titanate-based main component included in at least one of the side edge portions 20 and 20 ′ and the effective portion 10 , a description thereof is omitted.

[0139] For example, the secondary component powder may include at least one selected from the group consisting of manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), germanium (Ge), gallium (Ga), indium (In), barium (Ba), lanthanum (La), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), gadolinium (Hf), vanadium (V), and combinations thereof, but the present disclosure is not limited thereto. Based on 100 parts by mole of the barium titanate-based main component powder, the content of the secondary component powder included may be in the range of 0.01 parts by mole to 5 parts by mole.

[0140] The subcomponent powder may be used in the form of an oxide or salt compound including a metal, or may be used in the form of a sol dispersed in an organic solvent.

[0141] In addition, the dielectric slurry may be prepared by further mixing additives (eg, a dispersant, a binder, a plasticizer, a lubricant, an antistatic agent, etc.) and a solvent.

[0142] In some embodiments, a wet ball mill or a stirred mill can be used to mix the barium titanate-based main component and the auxiliary component powder. When a zirconia ball is used in a wet ball mill, a plurality of zirconia balls with a diameter of 0.1 mm to 10 mm can be used for wet mixing for 8 to 48 hours or 10 to 24 hours.

[0143] The prepared dielectric slurry is formed into a dielectric layer after firing.

[0144] The method for molding the prepared dielectric slurry into a sheet shape may include a belt molding method such as a doctor blade method, a casting roll method, etc. For example, the method for molding the prepared dielectric slurry may use a head discharge type roll molding coater, and a dielectric green sheet may be obtained by drying the molded body.

[0145] In order to form a conductive paste layer that becomes an inner electrode layer after firing, a conductive paste can be prepared by mixing a conductive powder (made of a conductive metal or its alloy), a binder and a solvent. In addition, if necessary, barium titanate powder can be mixed together as a common material. The common material can be used to suppress the sintering of the conductive powder during the firing process. The conductive paste layer is formed by applying the conductive paste to the surface of the dielectric green sheet in a predetermined pattern using various printing methods such as screen printing or transfer methods.

[0146] The conductive paste layer may be coated only on some areas of the surface of the dielectric green sheet. In some embodiments, when the conductive paste layer is coated on the surface of the dielectric green sheet, the conductive paste layer may not be coated on an area of ​​the surface of the dielectric green sheet that is an edge area. The dielectric green sheets prepared above may be stacked.

[0147] Next, a plurality of dielectric green sheets formed with internal electrode patterns are stacked to manufacture a dielectric green sheet laminate. In this case, the dielectric green sheets and the internal electrode patterns may be stacked so that the dielectric green sheets are disposed on the upper and lower surfaces of the dielectric green sheet laminate in the stacking direction. The formed dielectric green sheet laminate may be pressed in the stacking direction.

[0148] Next, the manufactured dielectric green sheet laminate is cut into a predetermined size by dicing, etc. In this case, the dielectric green sheet laminate is cut in a state where the conductive paste layer is exposed without leaving a region where the conductive paste layer is not applied as a margin region.

[0149] Furthermore, if necessary, the dielectric green sheet stack may be cured and dried to remove the plasticizer, etc., and after curing and drying the dielectric green sheet stack, the cured and dried stack may be drum polished using a horizontal centrifugal drum machine, etc. In drum polishing, the dielectric green sheet stack may be placed in a drum container together with a medium and a polishing liquid, and a rotational motion or vibration may be applied to the drum container so that unnecessary portions (such as burrs, etc.) generated during cutting are polished. In addition, after drum polishing, the dielectric green sheet stack may be washed with a cleaning solution (such as water, etc.), and the washed stack may be dried.

[0150] Next, the previously prepared edge sheet having an adhesive surface is bonded to the cut surface of the dielectric green sheet laminate.

[0151] Next, the capacitor body can be manufactured by removing the binder from the dielectric green sheet laminate to which the edge sheet is bonded and firing the dielectric green sheet laminate from which the binder is removed.

[0152] Figure 4 is a schematic diagram illustrating a process of forming a side margin part in a method of manufacturing a multilayer ceramic capacitor according to some embodiments.

[0153] Reference Figure 4 As described above, after the dielectric green sheet laminate is pressed and cut, an edge sheet having an adhesive surface is bonded, and then the side edge portion connected to the effective portion is formed by firing the bonded edge sheet.

[0154] The binder removal treatment conditions may be appropriately adjusted according to the composition of the dielectric layer or the composition of the inner electrode layer. For example, the temperature rise rate during the binder removal treatment may be 5° C. / hour to 300° C. / hour, the carrier temperature during the binder removal treatment may be 180° C. to 400° C., and the temperature maintenance time during the binder removal treatment may be 0.5 hour to 24 hours. The atmosphere during the binder removal treatment may be an air atmosphere or a reducing atmosphere.

[0155] The conditions of the firing process may be appropriately adjusted according to the main component composition of the dielectric layer or the main component composition of the inner electrode. For example, the firing may be performed at a temperature of 1100° C. to 1400° C. or 1200° C. to 1350° C. In addition, the firing may be performed for 0.5 hours to 8 hours or 1 hour to 3 hours. In addition, the firing may be performed in a reducing atmosphere (for example, an atmosphere of a humidified mixed gas including nitrogen and hydrogen). If the inner electrode includes nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the firing atmosphere may be 1.0×10 -14 MPa to 1.0×10 -10 MPa.

[0156] After the firing process, annealing may be performed if necessary. Annealing may be a process for reoxidizing the dielectric layer, and may be performed if the firing process is performed in a reducing atmosphere. The conditions of the annealing process may be appropriately adjusted according to the composition of the dielectric layer. For example, the temperature during the annealing may be 950° C. to 1150° C., the time during the annealing may be 0 hours to 20 hours, and the heating rate during the annealing may be 50° C. / hour to 500° C. / hour. The annealing atmosphere may be humidified nitrogen (N 2 ) atmosphere, and the oxygen partial pressure in the annealing atmosphere may be 1.0×10 -9 MPa to 1.0×10 -5 MPa.

[0157] In the binder removal process, the firing process, or the annealing process, for example, a wetting agent or the like may be used to humidify the nitrogen gas or the mixed gas or the like. In this case, the temperature of the wetting agent (for example, water) may be 5° C. to 75° C. The binder removal process, the firing process, or the annealing process may be performed sequentially or may be performed independently.

[0158] In some embodiments, surface treatment (such as sandblasting, laser irradiation, barrel polishing, etc.) may be performed on the third and fourth surfaces of the manufactured capacitor body 110. By performing the surface treatment, the end of the first inner electrode may be exposed on the third surface, and the end of the second inner electrode may be exposed on the fourth surface. Therefore, the electrical bonding between the first outer electrode and the first inner electrode and the electrical bonding between the second outer electrode and the second inner electrode may become good, and the alloy portion may be easily formed.

[0159] Next, external electrodes are formed on the surface of the manufactured capacitor body 110 .

[0160] For example, a paste for forming a sintered metal layer may be applied to the capacitor body 110 , and then the applied paste for forming a sintered metal layer may be sintered to form the sintered metal layer.

[0161] The paste for forming the sintered metal layer may include conductive metal and glass. The description of the conductive metal and glass is the same as the above description, so their repeated description is omitted. In addition, the paste for forming the sintered metal layer may selectively include a binder, a solvent, a dispersant, a plasticizer, an oxide powder, etc. For example, the binder may use ethyl cellulose, acryl, butyral, etc., and for example, the solvent may use an organic solvent (e.g., terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, toluene, etc.) or an aqueous solvent.

[0162] The method for applying the paste for forming the sintered metal layer to the outer surface of the capacitor body 110 may include a dipping method, various printing methods (such as screen printing, etc.), a coating method using a dispenser, etc., a spraying method using a spray, etc. The paste for forming the sintered metal layer may be applied to at least the third surface and the fourth surface of the capacitor body 110, and may be selectively applied to a portion of the first surface, a portion of the second surface, a portion of the fifth surface, or a portion of the sixth surface (where the band portion of each of the first external electrode and the second external electrode is formed).

[0163] Thereafter, the capacitor body 110 on which the paste for forming the sintered metal layer is applied may be dried, and the dried capacitor body may be sintered at a temperature of 700° C. to 1000° C. for 0.1 to 3 hours to form the sintered metal layer.

[0164] In some embodiments, a paste for forming the conductive resin layer may be applied to the outer surface of the capacitor body 110 , and then the applied paste may be cured to form the conductive resin layer.

[0165] The paste for forming the conductive resin layer may include resin, and may optionally include conductive metal or non-conductive filler. The description of conductive metal and resin is the same as described above, so their repeated description is omitted. In addition, the paste for forming the conductive resin layer may optionally include adhesive, solvent, dispersant, plasticizer, oxide powder, etc. For example, the adhesive may include ethyl cellulose, acryl, butyral, etc., and for example, the solvent may be an organic solvent (for example, terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone, toluene, etc.) or an aqueous solvent.

[0166] In some embodiments, the conductive resin layer may be formed by immersing the capacitor body 110 in a paste for forming a conductive resin layer and then curing the impregnated paste, the conductive resin layer may be formed by printing the paste for forming a conductive resin layer on the surface of the capacitor body 110 using screen printing, gravure printing, etc., or the conductive resin layer may be formed by applying the paste for forming a conductive resin layer to the surface of the capacitor body 110 and then curing the applied paste.

[0167] Next, a plating layer may be formed on the outside of the conductive resin layer.

[0168] For example, the plated layer may be formed by a plating method, or may be formed by sputtering or electrodeposition.

[0169] Hereinafter, the above implementation examples will be described in more detail through the following examples. However, the following examples are only for illustrative purposes and do not limit the scope of the present disclosure.

[0170] (Manufacture of multilayer ceramic capacitors)

[0171] Example 1

[0172] By mixing BaTiO 3 Powder, Ga 2 O 3 The coating composition is prepared by mixing 100 mol parts of BaTiO 3 Powder, mixed Ga 2 O 3 The content of the powder was 3 parts by mole, and the content of the mixed binder was 50% by weight based on the total amount of the coating composition. The prepared coating composition was applied to a BaTiO 3 On one surface of the edge sheet, thereby preparing an edge sheet having a sticky surface.

[0173] The dielectric slurry was prepared by using zirconium oxide (ZrO 2 ) balls as the dispersion medium, using BaTiO 3 The powder is added with ethanol (or toluene), a wetting dispersant and polyvinyl butyral (PVB) resin as a binder, and then mechanically ground.

[0174] Next, a dielectric green sheet was manufactured using the prepared dielectric slurry by a head discharge type roll-on forming coater. A conductive paste layer including nickel (Ni) was printed on the surface of the dielectric green sheet, and a dielectric green sheet laminate was manufactured by laminating and pressing the dielectric green sheets (width×length×height=3.2 mm×2.5 mm×2.5 mm) on which the conductive paste layer was formed.

[0175] The dielectric green sheet laminate is cut to expose the conductive paste layer without leaving a region where the conductive paste layer is not printed. An edge sheet having an adhesive surface is bonded to the cut surface of the dielectric green sheet laminate.

[0176] The dielectric green sheet laminate with the edge sheet bonded thereto is plasticized at 400° C. or less in a nitrogen atmosphere and fired at 1300° C. and 1.0% or less of hydrogen (H 2 ) concentration and firing the dielectric green sheet stack.

[0177] Subsequently, a multilayer ceramic capacitor is manufactured through processes such as forming external electrodes, plating, and the like.

[0178] Example 2

[0179] A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that when the coating composition was prepared in Example 2, based on 100 parts by mole of BaTiO 3 Powder, mixed Ga 2 O 3 The content of the powder was 6 parts by mole.

[0180] Comparative Example 1

[0181] A multilayer ceramic capacitor was manufactured in the same manner as in Example 1 except that when Comparative Example 1. No Ga was used in preparing the coating composition. 2 O 3 powder.

[0182] Assessment 1: SEM-EDS analysis

[0183] The multilayer ceramic capacitors manufactured in Examples 1 and 2 were subjected to scanning electron microscope (SEM)-energy dispersive spectroscopy (EDS) analysis to confirm the presence and content of gallium (Ga) at various locations, and the results are shown in FIG. Figure 5A and Figure 5B middle.

[0184] SEM-EDS analysis was performed using the following method.

[0185] The following cross-sectional samples are obtained: After the multilayer ceramic capacitor 100 manufactured in Examples 1 and 2 is placed in an epoxy resin mixed liquid (or epoxy resin mixture) and the placed multilayer ceramic capacitor 100 is cured, the surface (WT surface) in the W-axis direction and the T-axis direction of the capacitor body 110 is polished to 1 / 2 point in the L-axis direction, and the polished capacitor body is kept in a vacuum atmosphere chamber to observe the effective part (where the dielectric layer 111 and each of the internal electrode layers 121 and 122 are stacked on each other) and the side edge part. Next, the cross-sectional sample with the WT surface is divided into two halves in the width direction (W-axis direction) to measure the side edge part and the effective part on one side using a scanning electron microscope (SEM). For example, the SEM is a VeriosG4 product from Thermo fisher Scientific Inc., the measurement conditions are 10kV and 0.2nA, the analysis magnification is 10k times, and 10 or more layers in the dielectric layer 111 and the internal electrode layers 121 and 122 are measured.

[0186] Subsequently, EDS analysis is performed in the SEM image of the obtained cross-sectional sample. In the SEM image of the obtained cross-sectional sample, the side edge portion is substantially equally divided into two regions in the width direction, so that the region closer to the junction in the two regions is called the first side edge portion, and the remaining region in the two regions is called the second side edge portion. In addition, the effective portion includes a border adjacent region, which is defined as a region whose length from the boundary between the effective portion and each junction in the width direction toward the effective portion corresponds to two to three times the width direction length of each side edge portion in the SEM image, and the border adjacent region of the effective portion is substantially equally divided into two regions in the width direction, so that the region closer to the junction in the two regions is called the first effective portion, and the remaining region in the two regions is called the second effective portion. Here, the content of gallium (Ga) is measured at at least one point of each of the first side edge portion, the second side edge portion, the first effective portion, and the second effective portion.

[0187] Figure 5A is a graph showing the content of gallium (Ga) at various positions in the multilayer ceramic capacitor according to Example 1, and Figure 5B is a graph showing the content of gallium (Ga) at various positions in the multilayer ceramic capacitor according to Example 2.

[0188] Reference Figure 5A and Figure 5BIn Examples 1 and 2, it can be seen that at least one of the effective portion (site 1 and site 2) and the side edge portion (site 3 and site 4) includes gallium (Ga). In addition, it can be seen that the gallium (Ga) included in the first side edge portion (site 3) is higher than that in the second side edge portion (site 4).

[0189] Assessment 2: SEM analysis

[0190] The multilayer ceramic capacitors manufactured in Examples 1 and 2 and Comparative Example 1 were subjected to scanning electron microscope (SEM) analysis to confirm the pore generation rate at the end of the inner electrode layer, and the results are shown in FIG. FIG. 6A to FIG. 6C middle.

[0191] First, SEM analysis is performed as follows. The following cross-sectional samples are obtained: After the multilayer ceramic capacitor 100 manufactured in Example 1, Example 2 or Comparative Example 1 is placed in an epoxy resin mixture (or epoxy resin mixture) and the placed multilayer ceramic capacitor 100 is cured, the surface (WT surface) in the W-axis direction and the T-axis direction of the capacitor body 110 is polished to the 1 / 2 point in the L-axis direction, and the polished capacitor body is kept in a vacuum atmosphere chamber to observe the effective portion (where the dielectric layer 111 and each of the internal electrode layers 121 and 122 are stacked on each other) and the side edge portion. Next, the cross-sectional sample with the WT surface is divided into two halves in the width direction (W-axis direction) so that the side edge portion and the effective portion on one side are measured using a scanning electron microscope (SEM). Therefore, the end of the internal electrode layer can be clearly seen. For example, the SEM is VeriosG4 product from Thermo Fisher Scientific Inc., the measurement conditions are 2 kV and 0.2 nA, the analysis magnification is 10 k times, and 20 or more layers of the dielectric layer 111 and the internal electrode layers 121 and 122 are measured.

[0192] The pore generation rate at the end of the inner electrode layer in the SEM image of the cross-sectional sample is obtained by the following Equation 1.

[0193] [Equation 1]

[0194] Hole generation rate at the end of the internal electrode layer = (number of internal electrode layers having holes at the end of the internal electrode layer / total number of internal electrode layers) × 100%

[0195] Fig. 6A is a SEM image showing that holes are generated at the end portions of the internal electrode layers in the multilayer ceramic capacitor according to Example 1. Figure 6B is a SEM image showing that holes are generated at the end portions of the internal electrode layers in the multilayer ceramic capacitor according to Example 2. Figure 6Cis a SEM image showing generated holes at the end portions of the internal electrode layers in the multilayer ceramic capacitor according to Comparative Example 1.

[0196] Reference FIG. 6A to FIG. 6C , it can be seen that the hole generation rate at the end of the inner electrode layer of Example 1 is 39%, the hole generation rate at the end of the inner electrode layer of Example 2 is 27%, but the hole generation rate at the end of the inner electrode layer of Comparative Example 1 is 78%. It can be seen that the multilayer ceramic capacitor including gallium (Ga) in at least one of the effective portion and the side edge portion according to the present embodiment has excellent density at the end of the inner electrode layer. Therefore, moisture resistance reliability and voltage resistance characteristics can be improved.

[0197] Evaluation 3: Moisture resistance reliability

[0198] The moisture resistance reliability of the multilayer ceramic capacitors manufactured in Examples 1 and 2 and Comparative Example 1 was measured, and the results are shown in FIG. 7A to 7C middle.

[0199] Specifically, 80 multilayer ceramic capacitors manufactured in each of Examples 1 and 2 and Comparative Example 1 were prepared to be mounted on a measurement substrate, and the moisture resistance reliability of the multilayer ceramic capacitors was measured using ESPEC (PR-3J, 8585) equipment under the conditions of 85°C, 85% relative humidity (RH), 6.3 V and 8 hours.

[0200] Fig. 7A is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Example 1. Figure 7B is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Example 2. Figure 7C is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Comparative Example 1.

[0201] Reference 7A to 7C , it can be seen that Examples 1 and 2 including gallium (Ga) in at least one of the effective portion and the side edge portion have excellent moisture resistance reliability compared to Comparative Example 1.

[0202] While the present disclosure has been described in connection with what are presently considered to be practical embodiments, it should be understood that the present disclosure is not limited to the disclosed embodiments, but on the contrary, the present disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0203] <Description of symbols>

[0204] 100: Multilayer ceramic capacitors

[0205] 110: Capacitor body

[0206] 111: Dielectric layer

[0207] 121: First inner electrode

[0208] 122: Second inner electrode

[0209] 131: First outer electrode

[0210] 132: Second outer electrode

[0211] 10: Effective part

[0212] 15, 15': Boundary vicinity

[0213] 16, 16': First effective part

[0214] 17, 17': Second effective part

[0215] 20, 20': Side edge

[0216] 21, 21': first side edge portion

[0217] 22, 22': second side edge portion

[0218] 30, 30': Joint.

Claims

1. A multilayer ceramic capacitor comprising: a capacitor body including a dielectric layer and an inner electrode layer; as well as an outer electrode disposed on an outer surface of the capacitor body, in, The capacitor body includes an effective portion where the dielectric layers and the internal electrode layers are alternately arranged, side edge portions arranged at two side ends of the effective portion opposite to each other, and joint portions respectively arranged between the effective portion and the side edge portions, and At least one of the effective portion and the side edge portion includes a barium titanate-based main component including barium and titanium, and gallium.

2. The multilayer ceramic capacitor according to claim 1, wherein The side edge portion includes the barium titanate-based main component and gallium.

3. The multilayer ceramic capacitor according to claim 2, wherein: Each of the side edge portions is divided into a first side edge portion and a second side edge portion in the width direction, The first side edge portion is a region of each side edge portion closer to the joining portion; The second side edge portion is a remaining area of ​​each side edge portion except the first side edge portion, and The first side margin portion includes gallium.

4. The multilayer ceramic capacitor according to claim 3, wherein: The first side margin portion may include gallium in an amount within a range of greater than 0 parts by weight and less than or equal to 1.5 parts by weight based on 100 parts by weight of barium included in the first side margin portion.

5. The multilayer ceramic capacitor according to claim 3, wherein: Gallium is included in the first side margin portion and the second side margin portion, and a content of gallium included in the first side margin portion is higher than a content of gallium included in the second side margin portion.

6. The multilayer ceramic capacitor according to claim 1, wherein The effective portion includes the barium titanate-based main component and gallium.

7. The multilayer ceramic capacitor according to claim 6, wherein: The effective portion includes a boundary adjacent region, which is defined as a region whose length from a boundary between the effective portion and each of the combining portions in the width direction of the capacitor body toward the effective portion corresponds to two to three times the width direction length of each of the side edge portions, and includes gallium in the boundary adjacent region of the effective portion.

8. The multilayer ceramic capacitor according to claim 7, wherein: The border vicinity of the effective portion is divided into a first effective portion and a second effective portion in the width direction, The first effective portion is a region of the boundary-adjacent region closer to the joining portion. The second effective portion is a remaining area of ​​the border-adjacent area except the first effective portion. Gallium is included in the first active portion and the second active portion, A content of gallium included in the first effective portion is higher than a content of gallium included in the second effective portion.

9. The multilayer ceramic capacitor according to claim 1, wherein: Each of the side edge portion and the effective portion includes the barium titanate-based main component and gallium.

10. The multilayer ceramic capacitor according to claim 9, wherein A content of gallium included in the side edge portion is higher than a content of gallium included in the effective portion.

11. The multilayer ceramic capacitor according to claim 1, wherein The bonding portion includes a barium titanate-based compound including barium and titanium, and gallium.

12. The multilayer ceramic capacitor according to claim 11, wherein The bonding part may include gallium in an amount ranging from 0.3 parts by weight to 1.5 parts by weight based on 100 parts by weight of barium.

13. The multilayer ceramic capacitor according to claim 1, wherein For the bonding surface between the effective portion and the bonding portion, a pore generation rate at the end of the inner electrode layer obtained by the following Equation 1 is greater than 0% and less than or equal to 40%: [Equation 1] Hole generation rate at the end of the internal electrode layer=(the number of internal electrode layers having holes at the end of the internal electrode layer / the total number of the internal electrode layers)×100%.

14. A method of manufacturing a multilayer ceramic capacitor, comprising: preparing an edge sheet having an adhesive surface by applying a coating composition including a barium titanate-based compound and gallium to at least one surface of the edge sheet; manufacturing a dielectric green sheet using a dielectric slurry and forming a conductive paste layer on a surface of the dielectric green sheet; manufacturing a dielectric green sheet laminate by laminating dielectric green sheets on which the conductive paste layer is formed; cutting the dielectric green sheet laminate in a state where the conductive paste layer is exposed without leaving a region where the conductive paste layer is not formed; bonding the edge sheet having the adhesive surface to the cut surface of the dielectric green sheet stack; manufacturing a capacitor body by firing the dielectric green sheet laminate incorporating the edge sheet; and forming external electrodes on a surface of the capacitor body, The capacitor body includes an effective portion where dielectric layers and internal electrode layers are alternately arranged, side edge portions arranged at two side ends of the effective portion opposite to each other, and joint portions respectively arranged between the effective portion and the side edge portions, and At least one of the effective portion and the side edge portion includes a barium titanate-based main component including barium and titanium, and gallium.

15. The method according to claim 14, wherein: The coating composition includes gallium in an amount ranging from greater than 0 parts by mole to equal to or less than 6 parts by mole based on 100 parts by mole of the barium titanate-based compound.

16. The method according to claim 14, wherein: Gallium is included in the coating composition as a gallium-containing oxide, a gallium-containing nitride, a gallium-containing salt compound, or a combination thereof.

17. The method according to claim 14, wherein: The coating composition also includes a binder.

18. A multilayer ceramic capacitor comprising: a capacitor body including a dielectric layer and an inner electrode layer; as well as An outer electrode is disposed on an outer surface of the capacitor body, in, The capacitor body includes an effective portion where the dielectric layers and the internal electrode layers are alternately arranged, side edge portions arranged at two side ends of the effective portion opposite to each other, and joint portions respectively arranged between the effective portion and the side edge portions, and The at least one bonding part among the bonding parts may include gallium in an amount ranging from 0.3 parts by weight to 1.5 parts by weight based on 100 parts by weight of barium of the at least one bonding part.

19. The multilayer ceramic capacitor according to claim 18, wherein: The at least one bonding part includes gallium in an amount ranging from 0.5 parts by weight to 1.2 parts by weight based on 100 parts by weight of barium in the at least one bonding part.

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