Multilayer ceramic capacitor and method of manufacturing the same

Abstract

To provide a multilayer ceramic capacitor and a method of manufacturing the same.SOLUTION: There are provided 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 internal electrode layer, and an external electrode disposed outside the capacitor body. The capacitor body includes: an active portion where the dielectric layer and the internal electrode layer are alternately disposed; side margin portions disposed at both side end portions of the active portion facing each other; and bonding portions disposed between the active portion and the side margin portions. At least one of the active portion or the side margin portions includes a barium titanate-based main ingredient including barium (Ba) and titanium (Ti), and gallium (Ga).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a multilayer ceramic capacitor and a manufacturing method thereof. [Background technology]

[0002] Electronic components using ceramic materials include capacitors, inductors, piezoelectric elements, varistors, thermistors, etc. Among these ceramic electronic components, multilayer ceramic capacitors (MLCCs) have the advantages of being small, having high capacitance, and being easy to mount, and can be used in a variety of electronic devices.

[0003] For example, multilayer ceramic capacitors (MLCCs) are mounted on the substrates of various electronic products such as visual devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), and organic light-emitting diodes (OLEDs), computers, personal portable terminals, and smartphones, and can be used as chip-type capacitors that charge and discharge electricity.

[0004] On the other hand, multilayer ceramic capacitors (MLCCs) are made of BaTiO 3 The internal structure is made up of alternately laminated dielectric layers and Ni internal electrode layers, and the BaTiO 3 Such an external structure has problems such as crack generation due to external stress and deterioration of electrical characteristics due to steps occurring in areas where there are no internal electrode layers. Summary of the Invention [Problem to be solved by the invention]

[0005] An embodiment provides a multilayer ceramic capacitor having excellent moisture resistance reliability and voltage resistance characteristics due to improved termination density of internal electrode layers.

[0006] Another embodiment provides a method for manufacturing the multilayer ceramic capacitor. [Means for solving the problem]

[0007] One embodiment provides a multilayer ceramic capacitor that includes a capacitor body including a dielectric layer and an internal electrode layer, and an external electrode arranged on the outside of the capacitor body, the capacitor body including an active section in which the dielectric layers and the internal electrode layers are arranged alternately with each other, side margin sections arranged on both opposing ends of the active section, and a joint section arranged between the active section and the side margin section, and at least one of the active section and the side margin section includes a barium titanate-based main component including barium (Ba) and Ti (titanium), and gallium (Ga).

[0008] The barium titanate-based main component and the gallium (Ga) are contained in the side margin portion.

[0009] When the side margin portion is divided in half in the width direction, with the region closest to the junction being designated as a first side margin portion and the remaining region being designated as a second side margin portion, the gallium (Ga) is contained in the first side margin portion.

[0010] The gallium (Ga) is contained in the first side margin portion in an amount of more than 0 part by weight and not more than 1.5 parts by weight with respect to 100 parts by weight of the barium (Ba).

[0011] The gallium (Ga) is contained in the first side margin portion and the second side margin portion, and the gallium (Ga) is contained in a higher content in the first side margin portion than in the second side margin portion.

[0012] The barium titanate-based main component and the gallium (Ga) are contained in the active portion.

[0013] The active portion may include a boundary vicinity region defined as a region from the boundary surface with the junction to a point having a length equivalent to two to three times the width direction length of the side margin portion, and the gallium (Ga) is included in the boundary vicinity region of the active portion.

[0014] When the boundary vicinity region of the active section is divided in two in the width direction, the region closest to the junction is designated as a first active section, and the remaining region is designated as a second active section, the gallium (Ga) is contained in both the first active section and the second active section, and the gallium (Ga) is contained in a higher content in the first active section than in the second active section.

[0015] The barium titanate-based main component and the gallium (Ga) are contained in the side margin portion and the active portion.

[0016] The gallium (Ga) is contained in a higher content in the side margin portion than in the active portion.

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

[0018] The gallium (Ga) is contained in the joint in an amount of 0.3 parts by weight to 1.5 parts by weight with respect to 100 parts by weight of the barium (Ba).

[0019] The pore generation rate of the end portion of the internal electrode layer, which is obtained by the following Equation 1 with respect to the joint surface between the active part and the joint part, may be more than 0% to 40%. [Formula 1] Porosity occurrence rate (%) of the end part of the internal electrode layer = (number of internal electrode layers having pores at the end part / total number of internal electrode layers) x 100

[0020] Another embodiment includes the steps of: applying a coating composition including a barium titanate-based compound and gallium (Ga) to at least one surface of a margin sheet to prepare a margin sheet having an adhesive surface; manufacturing a dielectric green sheet using a dielectric slurry and forming a conductive paste layer on the surface of the dielectric green sheet; stacking the dielectric green sheets having the conductive paste layer formed thereon to manufacture a dielectric green sheet laminate; cutting the dielectric green sheet laminate in a state where the conductive paste layer is exposed without leaving any area where the conductive paste layer is not formed; and bonding the margin sheet having the adhesive surface to the cut surface of the cut dielectric green sheet laminate. a step of bonding the dielectric green sheet laminate to the dielectric green sheet to form a capacitor body; and a step of forming an external electrode on one side of the capacitor body, wherein the capacitor body includes an active section in which dielectric layers and internal electrode layers are alternately arranged, side margin sections arranged on both opposing side ends of the active section, and a joint section arranged between the active section and the side margin section, and at least one of the active section and the side margin section contains a barium titanate-based main component containing barium (Ba) and Ti (titanium), and gallium (Ga).

[0021] The coating composition may contain the gallium (Ga) in an amount of more than 0 to 6 parts by mole based on 100 parts by mole of the barium titanate-based compound.

[0022] The gallium (Ga) is contained 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.

[0023] The coating composition may further comprise a binder. Effect of the Invention

[0024] The multilayer ceramic capacitor according to an embodiment may have improved termination density of the internal electrode layers, and thus may have excellent moisture resistance reliability and voltage resistance characteristics. [Brief description of the drawings]

[0025] [Figure 1] 1 is a perspective view illustrating a multilayer ceramic capacitor according to an embodiment; [Diagram 2] 2 is a cross-sectional view of the multilayer ceramic capacitor taken along line II' in FIG. [Diagram 3] 2 is a cross-sectional view of the multilayer ceramic capacitor taken along line II-II' in FIG. [Figure 4] 4 is a schematic diagram illustrating a process of forming a side margin portion in a method for manufacturing a multilayer ceramic capacitor according to an embodiment; [Figure 5A] 4 is a graph showing the content of gallium (Ga) at each position in the multilayer ceramic capacitor according to Example 1. [Figure 5B] 11 is a graph showing the content of gallium (Ga) at each position in the multilayer ceramic capacitor according to Example 2. [Figure 6A] 4 is a SEM image showing pore formation at end portions of internal electrode layers in the multilayer ceramic capacitor according to Example 1. [Figure 6B] 11 is a SEM image showing pore formation at the end portions of internal electrode layers in the multilayer ceramic capacitor according to Example 2. [Figure 6C] 11 is a SEM image showing pores formed at end portions of internal electrode layers in the multilayer ceramic capacitor according to Comparative Example 1. [Figure 7A] 4 is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Example 1. [Figure 7B] 10 is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Example 2. [Figure 7C] 13 is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, with reference to the accompanying drawings, an embodiment of the present invention will be described in detail so that a person having ordinary skill in the art to which the present invention pertains can easily carry out the present invention. In the drawings, parts that are unnecessary for the explanation are omitted in order to clearly explain the present invention, and the same reference numerals are used for the same or similar components throughout the specification. In addition, in the accompanying drawings, some components are exaggerated, omitted, or shown in a schematic manner, and the size of each component does not completely reflect the actual size.

[0027] It should be understood that the attached drawings are merely intended to facilitate understanding of the embodiments disclosed in this specification, and do not limit the technical ideas disclosed in this specification, but include all modifications, equivalents, or alternatives included in the idea and technical scope of the present invention.

[0028] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited by the terms. The terms are used only to distinguish one component from another.

[0029] In addition, when a part such as a layer, film, region, or plate is said to be "above" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. Furthermore, being "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" the opposite direction of gravity.

[0030] It should be understood that, throughout the specification, the terms "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Thus, when a part "comprises" a certain element, this means that it can further include other elements, but not to the exclusion of other elements, unless specifically stated to the contrary.

[0031] Also, throughout the specification, "on a plane" means when the subject part is viewed from above, and "on a cross section" means when the subject part is cut vertically and viewed from the side.

[0032] Furthermore, throughout the specification, when the term "connected" is used, this does not only mean that two or more components are directly connected, but also that two or more components are indirectly connected via other components, and can mean not only that they are physically connected but also that they are electrically connected, or that they are referred to by different names depending on their position or function.

[0033] Hereinafter, a multilayer ceramic capacitor according to an embodiment will be described with reference to FIGS.

[0034] FIG. 1 is a perspective view showing a multilayer ceramic capacitor according to one embodiment, FIG. 2 is a cross-sectional view of the multilayer ceramic capacitor taken along line II' in FIG. 1, and FIG. 3 is a cross-sectional view of the multilayer ceramic capacitor taken along line II-II' in FIG. 1.

[0035] The L axis, W axis, and T axis shown in Figs. 1 to 3 respectively indicate the longitudinal direction, width direction, and thickness direction of the capacitor body 110. Here, the thickness direction (T axis direction) may be a direction perpendicular to the wide surface (main surface) of the sheet-shaped component, and may be used in the same concept as the lamination direction in which the dielectric layers 111 are laminated, for example. The longitudinal direction (L axis direction) is a direction extending in parallel to the wide surface (main surface) of the sheet-shaped component and approximately perpendicular to the thickness direction (T axis direction), and may be, for example, a direction in which the first external electrode 131 and the second external electrode 132 are located on both sides. The width direction (W axis direction) may be a direction extending in parallel to the wide surface (main surface) of the sheet-shaped component and approximately perpendicular to the thickness direction (T axis direction) and the longitudinal direction (L axis direction), and the length of the longitudinal direction (L axis direction) of the sheet-shaped component is longer than the length of the width direction (W axis direction).

[0036] 1 to 3, a multilayer ceramic capacitor 100 according to an embodiment includes a capacitor body 110 and external electrodes 131 and 132 disposed on the outer side of the capacitor body 110. The external electrodes 131 and 132 may include a first external electrode 131 and a second external electrode 132 disposed on opposite ends of the capacitor body 110 in a longitudinal direction (L-axis direction).

[0037] For example, the capacitor body 110 may have a substantially hexahedral shape. For the convenience of describing one embodiment, in capacitor body 110, the two surfaces that face each other in the thickness direction (T-axis direction) are defined as the first surface and the second surface, and the two surfaces that are connected to the first surface and the second surface, the two surfaces that face each other in the longitudinal direction (L-axis direction) are defined as the third surface and the fourth surface, and the two surfaces that are connected to the first surface and the second surface and the third surface and the fourth surface, and the two surfaces that face each other in the width direction (W-axis direction) are defined as the fifth surface and the sixth surface.

[0038] As an example, the first surface of the lower surface is the surface facing the mounting direction. The first to sixth surfaces may be flat, but the embodiment is not limited to this. For example, the first to sixth surfaces may be curved surfaces with a convex center, and the corners that are the boundaries between the surfaces may be rounded.

[0039] The shape and size of the capacitor body 110 and the number of laminated dielectric layers 111 are not limited to those shown in the figure of this embodiment.

[0040] The capacitor body 110 includes a plurality of dielectric layers 111 and internal electrode layers 121 and 122. Specifically, the capacitor body 110 includes a plurality of dielectric layers 111, and first internal electrodes 121 and second internal electrodes 122 that are alternately arranged in the thickness direction (T-axis direction) with the dielectric layers 111 sandwiched between them.

[0041] At this time, the boundaries between the adjacent dielectric layers 111 of the capacitor body 110 are integrated to such an extent that it is difficult to confirm them without using a scanning electron microscope (SEM).

[0042] The capacitor body 110 may include an active section 10 in which dielectric layers and internal electrode layers are alternately arranged, side margin sections 20, 20' arranged at opposing both ends of the active section 10, and junction sections 30, 30' arranged between the active section 10 and the side margin sections 20, 20'.

[0043] The active section 10 is a portion that contributes to forming the capacitance of the multilayer ceramic capacitor 100. Specifically, the active section 10 may be a region where the first internal electrode 121 or the second internal electrode 122 that are laminated along the thickness direction (T-axis direction) overlap.

[0044] The side margin portions 20, 20' are arranged at both opposing end portions of the active portion 10 and can be considered as side cover portions, and can be located at both opposing end portions of the active portion 10 in the width direction (W-axis direction), i.e., on the fifth and sixth surface sides, respectively.

[0045] The capacitor body 110 may further include a cover portion. The cover portion is a margin portion in the thickness direction, and can be located in the thickness direction (T-axis direction) on the first and second surface sides of the active section 10. Such a cover portion can be a single dielectric layer 111 or two or more dielectric layers 111 laminated on the upper and lower surfaces of the active section 10, respectively.

[0046] The side margin portions 20, 20' and the cover portion serve to prevent the first internal electrode 121 and the second internal electrode 122 from being damaged due to physical or chemical stress.

[0047] The bonding portions 30, 30' are disposed between the active portion 10 and the side margin portions 20, 20' and serve to bond the side margin portions 20, 20' to the active portion 10.

[0048] The active portion 10 and at least one of the at least one side margin portion 20, 20' may include a barium titanate-based main component including barium (Ba) and titanium (Ti), and gallium (Ga).

[0049] The barium titanate-based main component is a dielectric base material having a high dielectric constant, and contributes to the formation of the dielectric constant of the multilayer ceramic capacitor 100 .

[0050] The main component of barium titanate is, for example, 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.

[0051] The gallium (Ga) contained in at least one of the active section 10 and the side margin sections 20, 20' may originate from a gallium (Ga) component added when forming the joint sections 30, 30'. That is, in the process of manufacturing the capacitor body 110, gallium (Ga) is a component contained in a coating composition for bonding a margin sheet forming the side margin section and a dielectric green sheet laminate forming the active section, and the gallium (Ga) is formed by diffusing into at least one of the active section 10 and the side margin sections 20, 20' after firing the bonded dielectric green sheet laminate.

[0052] When one or more of the active section 10 and at least one of the side margin sections 20, 20' contain gallium (Ga) components derived by diffusion into the components used in forming the junction sections 30, 30', the termination density of the internal electrode layer is improved, thereby improving the moisture resistance reliability and voltage resistance characteristics of the multilayer ceramic capacitor.

[0053] In a typical multilayer ceramic capacitor, since there is no internal electrode in the side margin region unlike the active region, a step may occur only in the space that is not printed. Such a step occurrence phenomenon may cause various problems such as crack occurrence due to external stress and deterioration of electrical characteristics. According to an embodiment, when cutting a dielectric green sheet laminate in a manufacturing process of a multilayer ceramic capacitor, the laminate is cut without leaving a margin region, that is, without leaving a region where a conductive paste layer that becomes an internal electrode layer is not formed, and the conductive paste layer is exposed, and then a margin sheet is attached to the cut surface to form a side margin portion, thereby manufacturing a multilayer ceramic capacitor by applying a margin formation (MF) method. When a coating composition that acts as a kind of adhesive when attaching a margin sheet to the cut surface in the MF method contains gallium (Ga), it is diffused after firing, and at least one of the active part 10 and the side margin parts 20, 20' contains gallium (Ga), so that the adhesive strength of the joint surface is excellent and the occurrence of delamination defects is suppressed, and the density of the joint surface after firing is sufficiently secured, thereby improving the moisture resistance reliability.

[0054] Specifically, the barium titanate-based main component and gallium (Ga) are contained in at least one of the side margin portions 20, 20', or are contained in the active portion 10. Also, the barium titanate-based main component and gallium (Ga) are contained in both the at least one of the side margin portions 20, 20' and the active portion 10. This is confirmed by SEM-EDS (scanning electron microscope-energy dispersive spectroscopy) analysis.

[0055] The SEM-EDS analysis is performed as follows. First, the multilayer ceramic capacitor 100 is put into an epoxy mixture and cured, and then the W-axis and T-axis directions (WT directions) of the capacitor body 110 are polished to 1 / 2 in the L-axis direction, and then fixed and maintained in a vacuum atmosphere chamber to obtain a cross-sectional sample so that the active part where the dielectric layer 111 and the internal electrode layers 121 and 122 intersect and the side margin part can be observed. Next, the cross-sectional sample having the WT direction is divided in half in the width (W-axis) direction, and one side margin part and the active part are measured with a scanning electron microscope (SEM). For example, a Verios G4 product from Thermofisher Scientific is used for the SEM, and the measurement conditions may be 10 kV, 0.2 nA, and an analysis magnification of 10 k times, and the measurement can be performed so that at least 10 layers of the dielectric layers 111 and the internal electrode layers 121 and 122 are exposed. Next, EDS (energy dispersive spectroscopy) analysis can be performed on the SEM image of the measured cross-sectional sample to confirm the presence of gallium (Ga) in at least one of the active area and the side margin area.

[0056] As an example, a barium titanate-based main component and gallium (Ga) are included in the side margin portions 20 and 20'. The side margin portions 20 and 20' may include the barium titanate-based main component and gallium (Ga) in at least one location on both sides. Also, the side margin portions 20, 20' can be divided in half in the width direction, with the region closer to the joint portion 30, 30' being the first side margin portions 21, 21', and the remaining region being the second side margin portions 22, 22'. In this case, gallium (Ga) is contained in at least one of the first side margin portions 21, 21'.

[0057] Specifically, gallium (Ga) is contained in an amount of more than 0 to 1.5 parts by weight, for example, 0.1 to 1.3 parts by weight, for example, 0.3 to 1.2 parts by weight, per 100 parts by weight of barium (Ba) in at least one first side margin portion 21, 21'. When gallium (Ga) is contained within the above content range in the first side margin portion 21, 21', the termination density of the internal electrode layer is improved, and the moisture resistance reliability and voltage resistance characteristics of the multilayer ceramic capacitor can be improved.

[0058] The gallium (Ga) content in the side margins 20 and 20' is confirmed by SEM-EDS analysis. Specifically, in an SEM image of a cross-sectional sample obtained by the above-mentioned method, the side margin is divided into two equal parts in the width direction, the area closer to the joint is designated as the first side margin, and the remaining area is designated as the second side margin. The gallium (Ga) content is measured at least one point, for example, 1 to 10 points or 1 to 5 points, in each of the first side margin and the second side margin, and the average value is calculated.

[0059] Also, gallium (Ga) is included in at least one first side margin portion 21, 21' and at least one second side margin portion 22, 22'. At this time, gallium (Ga) is included in a higher content in the first side margin portion 21, 21' than in the second side margin portion 22, 22'. When gallium (Ga) is included in a higher content in the first side margin portion 21, 21', which is closer to the active portion 10 among the side margin portions, the termination density of the internal electrode layer is improved, and the moisture resistance reliability and voltage resistance characteristics of the multilayer ceramic capacitor can be improved.

[0060] As another example, the active portion 10 contains a barium titanate-based main component and gallium (Ga).

[0061] The active section 10 may include boundary vicinity regions 15, 15' defined as a region extending from the boundary surface with the bonding sections 30, 30' to a point having a length equivalent to two to three times the width direction length of the side margin sections 20, 20'. Specifically, gallium (Ga) is included in at least one boundary vicinity region 15, 15' of the active section 10.

[0062] The boundary vicinity region 15, 15' of the active section 10 can be divided in half in the width direction to set the region closer to the junctions 30, 30' as the first active sections 16, 16', and the remaining region as the second active sections 17, 17'. In this case, gallium (Ga) is contained in the first active sections 16, 16' and the second active sections 17, 17'.

[0063] Specifically, gallium (Ga) is contained in a higher content in the first active portions 16, 16' than in the second active portions 17, 17'. When gallium (Ga) is contained in a higher content in the first active portions 16, 16', which are closer to the side margin portions 20, 20' among the boundary vicinity regions 15, 15' of the active portion 10, the termination density of the internal electrode layers is improved, thereby improving the moisture resistance reliability and voltage resistance characteristics of the multilayer ceramic capacitor.

[0064] The content of gallium (Ga) in the active part 10 is confirmed by SEM-EDS analysis. Specifically, in the SEM image of the cross-sectional sample obtained by the above-mentioned method, the boundary vicinity region is defined as a region in the active part from the boundary surface with the junction to a point having a length equivalent to two to three times the widthwise length of the side margin, and the boundary vicinity region of the active part is divided into two equal parts in the width direction, with the region closer to the junction being the first active part and the remaining region being the second active part. The gallium (Ga) content is measured at at least one point, for example, 1 to 10 points or 1 to 5 points, in each of the first active part and the second active part, and the average value is calculated.

[0065] As yet another example, the barium titanate-based main component and gallium (Ga) are all contained in at least one of the side margin portions 20, 20' and the active portion .

[0066] Specifically, gallium (Ga) is contained in a higher content in the side margin portions 20, 20' than in the active portion 10. When gallium (Ga) is contained in a higher content in the side margin portions 20, 20' than in the active portion 10, the termination density of the internal electrode layer is improved, and excellent moisture resistance reliability and voltage resistance characteristics can be obtained.

[0067] For example, gallium (Ga) is contained in at least one first side margin portion 21, 21' at a higher content than at least one second side margin portion 22, 22', and the first active portion 16, 16' at a lower content of gallium (Ga) than the second side margin portion 22, 22', and the second active portion 17, 17' at the lowest content of gallium (Ga).

[0068] According to one embodiment, at least one of the joints 30, 30' may include a barium titanate based compound including barium (Ba) and Ti (titanium), and gallium (Ga).

[0069] The barium titanate compound is, for example, 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.

[0070] The gallium (Ga) contained in the junctions 30 and 30' is formed by the gallium (Ga) component added when the junctions 30 and 30' are formed remaining as it is.

[0071] The gallium (Ga) in the joints 30 and 30' is contained in an amount of 0.3 to 1.5 parts by weight, for example, 0.5 to 1.2 parts by weight, relative to 100 parts by weight of barium (Ba). When the gallium (Ga) is contained in the joints 30 and 30' within the above content range, the termination density of the internal electrode layer is improved, and excellent moisture resistance reliability and voltage resistance characteristics can be obtained.

[0072] The Ga content in the junctions 30 and 30' is confirmed by SEM-EDS analysis. Specifically, in the SEM image of the cross-sectional sample obtained by the above-mentioned method, the Ga content is measured at at least one point, for example, 1 to 10 points, or 1 to 5 points in the junctions, and the average value is calculated.

[0073] The bonding portions 30, 30' are formed of a coating composition for bonding the margin sheets forming the side margin portions and the dielectric green sheet laminate forming the active portion. A detailed description of the coating composition will be given later in the description of the manufacturing method of the multilayer ceramic capacitor.

[0074] According to one embodiment, the porosity of the end of the internal electrode layer 121, 122 with respect to the joint surface between the active section 10 and the joint section 30, 30' may be more than 0% to 40% or less, for example, 1% to 35%. When the porosity of the end of the internal electrode layer is within the above range, it means that the end density of the internal electrode layer is excellent at the joint portion where the side margin portion is joined, and thus the moisture resistance reliability and the voltage resistance characteristics can be improved.

[0075] The porosity rate of the end of the internal electrode layer is measured as follows. After the multilayer ceramic capacitor 100 is immersed in an epoxy mixture and cured, the W-axis and T-axis directions (WT directions) of the capacitor body 110 are polished to 1 / 2 in the L-axis direction, and then the capacitor body is fixed and maintained in a vacuum atmosphere chamber to obtain a cross-sectional sample so that the active portion where the dielectric layer 111 and the internal electrode layers 121 and 122 intersect and the side margin portion can be observed. Next, the cross-sectional sample having the WT direction is divided in half in the width (W-axis) direction, and one side margin portion and the active portion can be measured with a scanning electron microscope (SEM) so that the end of the internal electrode layer can be clearly seen. The SEM used is, for example, a Verios G4 product from Thermofisher Scientific, with measurement conditions of 2 kV, 0.2 nA, and analysis magnification of 10k. At least 20 layers, for example 20 to 100 layers, or 20 to 50 layers of dielectric layers 111 and internal electrode layers 121, 122 can be measured.

[0076] The porosity rate of the terminal end of the internal electrode layer measured in this manner can be calculated by the following Equation 1. [Formula 1] Porosity occurrence rate (%) of the end part of the internal electrode layer = (number of internal electrode layers having pores at the end part / total number of internal electrode layers) x 100

[0077] The average thickness (average length in the T-axis direction) of the dielectric layers 111 may be 2.0 μm to 8.0 μm, for example, 2.4 μm to 7.8 μm. When the average thickness of the dielectric layers 111 is within the above range, the multilayer ceramic capacitor has excellent reliability.

[0078] The average thickness of the dielectric layer 111 is measured by immersing the multilayer ceramic capacitor 100 in an epoxy mixture, curing the multilayer ceramic capacitor 100, polishing the multilayer ceramic capacitor 100, and then performing ion milling and analyzing the multilayer ceramic capacitor 100 with a scanning electron microscope (SEM). The scanning electron microscope may be, for example, a Verios G4 product from Thermofisher Scientific, with measurement conditions of 10 kV, 0.2 nA, and an analysis magnification of 100 times, and at least one, three, five, or ten dielectric layers 111 may be measured. In the scanning electron microscope (SEM) image, the central point of the dielectric layer 111 in the longitudinal direction (L-axis direction) or width direction (W-axis direction) may be set as a reference point, and the average thickness may be an arithmetic average value of the thicknesses of the dielectric layer 111 at ten points spaced apart from the reference point at a predetermined interval. The interval between the 10 points can be adjusted according to the scale of a scanning electron microscope (SEM) image, and may be, for example, 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm. In this case, all of the 10 points must be located within the dielectric layer 111, and if all of the 10 points are not located within the dielectric layer 111, the position of the reference point can be changed or the interval between the 10 points can be adjusted.

[0079] The first internal electrode 121 and the second internal electrode 122 are electrodes having different polarities and are alternately arranged so as to face each other along the T-axis direction across the dielectric layer 111, and one end can be exposed through the third and fourth surfaces of the capacitor body 110, respectively.

[0080] The first internal electrode 121 and the second internal electrode 122 can be electrically insulated from each other by a dielectric layer 111 disposed therebetween.

[0081] Ends of the first internal electrode 121 and the second internal electrode 122 alternately exposed through the third and fourth surfaces of the capacitor body 110 can be electrically connected to the first external electrode 131 and the second external electrode 132, respectively.

[0082] The first internal electrode 121 and the second internal electrode 122 include a conductive metal, and may include, for example, a metal such as Ni, Cu, Ag, Pd, or Au, or an alloy thereof, for example, an Ag-Pd alloy.

[0083] Furthermore, the first internal electrode 121 and the second internal electrode 122 may contain dielectric particles having the same composition as the ceramic material contained in the dielectric layer 111 .

[0084] The first internal electrode 121 and the second internal electrode 122 are formed using a conductive paste containing a conductive metal. The conductive paste can be printed by screen printing or gravure printing.

[0085] The average thickness of the first internal electrode 121 and the second internal electrode 122 may be 0.1 μm to 2 μm. The average thickness of the first internal electrode 121 and the second internal electrode 122 is measured by scanning electron microscope (SEM) analysis. Here, the scanning electron microscope (SEM) analysis is the same as the method used to measure the average thickness of the dielectric layer 111 described above, so a description thereof will be omitted.

[0086] The capacitor body 110 is formed by firing a laminate in which a plurality of dielectric layers 111 and internal electrode layers 121 and 122 are laminated. A detailed method for manufacturing the capacitor body 110 according to an embodiment will be described later.

[0087] The first external electrode 131 and the second external electrode 132 are provided with voltages of different polarities and are electrically connected to exposed portions of the first internal electrode 121 and the second internal electrode 122, respectively.

[0088] With this configuration, when a predetermined voltage is applied to the first external electrode 131 and the second external electrode 132, charges are stored between the opposing first internal electrode 121 and second internal electrode 122. At this time, the capacitance of the multilayer ceramic capacitor 100 is proportional to the overlap area of ​​the first internal electrode 121 and the second internal electrode 122 that overlap each other along the T-axis direction in the active section.

[0089] The first external electrode 131 and the second external electrode 132 may each include first and second connection portions arranged on the third and fourth surfaces of the capacitor body 110 and connected to the first internal electrode 121 and the second internal electrode 122, respectively, and first and second band portions arranged at corners where the third and fourth surfaces of the capacitor body 110 meet the first and second surfaces or the fifth and sixth surfaces.

[0090] The first and second band portions may extend from the first and second connection portions to parts of the first and second faces or the fifth and sixth faces of the capacitor body 110. The first and second band portions may serve to improve the bonding strength between the first external electrode 131 and the second external electrode 132.

[0091] The first external electrode 131 and the second external electrode 132 may each include a sintered metal layer in contact with the capacitor body 110, a conductive resin layer arranged to cover the sintered metal layer, and a plating layer arranged to cover the conductive resin layer. The sintered metal layer can include a conductive metal and glass.

[0092] The conductive metal may include copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb), alloys thereof, or combinations thereof, for example, copper (Cu) may include copper (Cu) alloys. When the conductive metal includes copper, the metal other than copper is included in an amount of 5 molar parts or less per 100 molar parts of copper.

[0093] The glass may include a mixed oxide composition, such as one or more selected from the group consisting of silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, and alkaline earth metal oxide. The transition metal may be 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).

[0094] Alternatively, the conductive resin layer may be formed on the sintered metal layer, for example, to completely cover the sintered metal layer. Alternatively, the first external electrode 131 and the second external electrode 132 may not include a sintered metal layer, in which case the conductive resin layer may be in direct contact with the capacitor body 110.

[0095] The conductive resin layer extends on the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110, and the length of the region (i.e., band portion) where the conductive resin layer is arranged extending on the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110 is longer than the length of the region (i.e., band portion) where the sintered metal layer is arranged extending on the first and second surfaces 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 to completely cover the sintered metal layer.

[0096] The conductive resin layer includes a resin and a conductive metal. The resin contained in the conductive resin layer is not particularly limited as long as it has bonding and impact absorbing properties and can be mixed with the conductive metal powder to form a paste, and may include, for example, a phenolic resin, an acrylic resin, a silicone resin, an epoxy resin, or a polyimide resin.

[0097] The conductive metal contained in the conductive resin layer serves to electrically connect with the first internal electrode 121 and the second internal electrode 122 or the sintered metal layer.

[0098] The conductive metal contained in the conductive resin layer may have a spherical shape, a flake shape, or a combination thereof, that is, the conductive metal may be only flake-shaped, only spherical, or a mixture of flake-shaped and spherical shapes.

[0099] Here, the term "spherical" may include shapes that are not completely spherical, and may include shapes in which the ratio of the major axis to the minor axis (major axis / minor axis) is 1.45 or less. The term "flaky powder" refers to a powder having a flat and elongated shape, and is not particularly limited, and may include shapes in which the ratio of the major axis to the minor axis (major axis / minor axis) is 1.95 or more, for example.

[0100] The first external electrode 131 and the second external electrode 132 may further include a plating layer disposed on the outer side of the conductive resin layer.

[0101] The plating layer may include nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb) alone or in combination with an alloy thereof. For example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or may be a layer in which a nickel (Ni) plating layer and a tin (Sn) plating layer are sequentially laminated, or a layer in which a tin (Sn) plating layer, a nickel (Ni) plating layer, and a tin (Sn) plating layer are sequentially laminated. The plating layer may include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0102] The plating layer can improve the mountability of the multilayer capacitor 100 on a substrate, structural reliability, durability against the outside, heat resistance, and equivalent series resistance (ESR). A method for manufacturing the multilayer ceramic capacitor 100 according to an embodiment will now be described.

[0103] The multilayer ceramic capacitor 100 according to an embodiment may be manufactured by the steps of: preparing a margin sheet having an adhesive surface by applying a coating composition including a barium titanate-based compound and gallium (Ga) to at least one surface of the margin sheet; manufacturing a dielectric green sheet using a dielectric slurry and forming a conductive paste layer on the surface of the dielectric green sheet; stacking the dielectric green sheets having the conductive paste layer formed thereon to manufacture a dielectric green sheet laminate; cutting the dielectric green sheet laminate in a state in which the conductive paste layer is exposed without leaving any area in which the conductive paste layer is not formed; bonding the margin sheet having the adhesive surface to the cut surface of the cut dielectric green sheet laminate; firing the dielectric green sheet laminate to which the margin sheet is bonded to manufacture a capacitor body; and forming an external electrode on one surface of the capacitor body.

[0104] First, a coating composition is applied to at least one surface of a margin sheet to prepare a margin sheet having an adhesive surface. The coating composition includes a barium titanate-based compound and gallium (Ga).

[0105] The barium titanate-based compound may contain barium (Ba) and titanium (Ti), for example, 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.

[0106] Gallium (Ga) is contained 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 contained in the form of a Ga-containing oxide, such as gallium oxide (Ga 2 O 3 Gallium (Ga) can be used in the form of fine particles of, for example, 50 nm or less.

[0107] Gallium (Ga) is contained in an amount of more than 0 to 6 molar parts, for example, 0.5 to 5 molar parts, for example, 1 to 4 molar parts, relative to 100 molar parts of the barium titanate compound. When gallium (Ga) is contained in the coating composition in the above content range, the termination density of the internal electrode layer is improved, and a multilayer ceramic capacitor having excellent moisture resistance reliability and voltage resistance characteristics can be manufactured.

[0108] The coating composition may further include a binder to impart adhesion. The binder may be, for example, an acrylic resin, a polyvinyl butyral resin, a polyvinyl acetal resin, an ethyl cellulose resin, or the like.

[0109] The binder is included in an amount of 5 to 60 parts by weight, for example, 40 to 60 parts by weight, based on the total amount of the coating composition. When the binder is included within the above content range, the coating composition has excellent acid dispersion and provides sufficient adhesive strength to the bonding surface, thereby preventing the occurrence of delamination defects, and the bonding surface after firing has sufficient density, thereby providing a multilayer ceramic capacitor with excellent moisture resistance reliability.

[0110] The margin sheet is formed in the side margin portions 20, 20' after firing, and may contain a barium titanate-based main component. The barium titanate-based main component is the same as the barium titanate-based main component contained in at least one of the active portion 10 and the side margin portions 20, 20', so a description thereof will be omitted here.

[0111] 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.

[0112] The dielectric slurry can be produced by mixing a barium titanate-based main component powder and, optionally, a subcomponent powder.

[0113] The barium titanate-based main component powder is the same as the barium titanate-based main component contained in at least one of the active portion 10 and the side margin portions 20, 20', and therefore a description thereof will be omitted here.

[0114] The secondary component powders may include, but are not limited to, for example, 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), ruthenium (Lu), hafnium (Hf), vanadium (V), or combinations thereof. Each of the subcomponent powders is contained in an amount of 0.01 to 5 parts by mole relative to 100 parts by mole of the barium titanate-based main component powder.

[0115] The auxiliary component powders may be used in the form of oxides or salt compounds containing the respective metals, or in the form of a sol dispersed in an organic solvent.

[0116] The dielectric slurry may be prepared by additionally mixing additives such as a dispersant, a binder, a plasticizer, a lubricant, an antistatic agent, and a solvent.

[0117] A wet ball mill or an agitation mill can be used to mix the barium titanate-based main component powder and the optional subcomponent powder. When using zirconia balls in a wet ball mill, wet mixing can be performed for 8 to 48 hours, or 10 hours or 24 hours using multiple zirconia balls with diameters of 0.1 mm to 10 mm.

[0118] The prepared dielectric slurry is formed into a dielectric layer after firing. The produced dielectric slurry can be molded into a sheet shape using a tape molding method such as a doctor blade method or a calendar roll method, for example, an on-roll molding coater of a head discharge type, and then the molded body can be dried to obtain a dielectric green sheet.

[0119] To form a conductive paste layer that will become an internal electrode layer after firing, a conductive paste can be manufactured by mixing a conductive powder made of a conductive metal or its alloy, a binder, and a solvent. If necessary, barium titanate powder can be mixed in as a co-material. The co-material can suppress the sintering of the conductive powder during the sintering process. The conductive paste is applied in a predetermined pattern to the surface of the dielectric green sheet by various printing methods such as screen printing or transfer methods to form a conductive paste layer.

[0120] When applying a conductive paste layer to the surface of the dielectric green sheet, the conductive paste layer may be applied only to a portion of the surface of the dielectric green sheet, and dielectric green sheets without the conductive paste layer applied thereto may be laminated on both sides of the surface of the dielectric green sheet.

[0121] Next, the dielectric green sheets on which the internal electrode patterns are formed are laminated in a plurality of layers to manufacture a dielectric green sheet laminate. At this time, the dielectric green sheets and the internal electrode patterns can be laminated so that the dielectric green sheets are located on the upper and lower surfaces in the lamination direction of the dielectric green sheet laminate. The dielectric green sheet laminate is formed by pressing in the lamination direction.

[0122] Next, the manufactured dielectric green sheet laminate is cut to a predetermined size by dicing, etc. At this time, the dielectric green sheet laminate is cut in a state where the conductive paste layer is exposed without leaving any area where the conductive paste layer is not applied, i.e., any margin area.

[0123] Furthermore, the dielectric green sheet laminate can be solidified and dried to remove plasticizers, etc., as necessary, and after solidification and drying, can be barrel polished using a horizontal centrifugal barrel machine, etc. In barrel polishing, the dielectric green sheet laminate is placed in a barrel container together with media and polishing liquid, and unnecessary parts such as burrs generated during cutting can be polished by applying rotational motion, vibration, etc. to the barrel container. Furthermore, after barrel polishing, the dielectric green sheet laminate can be washed with a cleaning liquid such as water and dried.

[0124] Next, the previously prepared margin sheet having an adhesive surface is bonded to the cut surfaces of the cut dielectric green sheet laminate.

[0125] Next, the dielectric green sheet laminate to which the margin sheet is joined is subjected to a binder removal process and a firing process to manufacture a capacitor body.

[0126] FIG. 4 is a schematic view showing a process of forming a side margin portion in a method for manufacturing a multilayer ceramic capacitor according to an embodiment.

[0127] Referring to FIG. 4, as described above, after the dielectric green sheet laminate is compressed and cut, a margin sheet having an adhesive surface is bonded to the laminate, and then a firing process is performed to form a side margin portion bonded to the active portion.

[0128] The binder removal treatment conditions can be appropriately adjusted depending on the components of the dielectric layers and the internal electrode layers. For example, the temperature increase rate during the binder removal treatment may be 5°C / hour to 300°C / hour, the holding temperature may be 180°C to 400°C, and the temperature maintenance time may be 0.5 hours to 24 hours. The atmosphere during the binder removal treatment may be air or a reducing atmosphere.

[0129] The firing conditions can be appropriately adjusted depending on the composition of the main components of the dielectric layers and the main components of the internal electrodes. For example, firing is performed at a temperature of 1100°C to 1400°C, for example, at a temperature of 1200°C to 1350°C. Furthermore, firing is performed for 0.5 hours to 8 hours, for example, 1 hour to 3 hours. Furthermore, firing is performed in a reducing atmosphere, for example, an atmosphere of humidified mixed gas of nitrogen and hydrogen. When the internal electrodes contain nickel (Ni) or nickel (Ni) alloy, the oxygen partial pressure in the firing atmosphere is 1.0×10 -14 MPa~1.0×10 -10 It may be MPa.

[0130] After the firing treatment, annealing can be carried out as necessary. Annealing is a treatment for reoxidizing the dielectric layer, and annealing can be carried out when the firing treatment is carried out in a reducing atmosphere. The conditions of the annealing treatment can also be appropriately adjusted depending on the components of the dielectric layer. For example, the temperature during annealing may be 950°C to 1150°C, the time may be 0 hours to 20 hours, and the temperature increase rate may be 50°C / hour to 500°C / hour. The annealing atmosphere may be humidified nitrogen gas (N 2 ) atmosphere, and the oxygen partial pressure is 1.0×10 -9 MPa~1.0×10 -5 It may be MPa.

[0131] In the binder removal treatment, firing treatment, or annealing treatment, for example, a wetter can be used to moisten the nitrogen gas or mixed gas, and in this case, the water temperature may be 5° C. to 75° C. The binder removal treatment, firing treatment, and annealing treatment may be performed consecutively or independently.

[0132] Optionally, surface treatment such as sandblasting, laser irradiation, barrel polishing, etc. may be performed on the third and fourth faces of the manufactured capacitor body 110. By performing such surface treatment, the ends of the first and second internal electrodes are exposed on the outermost surfaces of the third and fourth faces, which improves the electrical connection between the first and second external electrodes and the first and second internal electrodes, making it easier to form an alloy part.

[0133] Next, an external electrode is formed on one surface of the manufactured capacitor body 110 . As an example, a paste for forming a sintered metal layer can be applied to the external electrodes and then sintered to form a sintered metal layer.

[0134] The paste for forming the sintered metal layer may include a conductive metal and glass. The conductive metal and glass have been described above, and therefore will not be described again. The paste for forming the sintered metal layer may selectively include a binder, a solvent, a dispersant, a plasticizer, an oxide powder, and the like. The binder may be, for example, ethyl cellulose, acrylic, butyral, and the solvent may be, for example, an organic solvent or an aqueous solvent such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, or toluene.

[0135] The method of applying the sintered metal layer forming paste to the outer surface of the capacitor body 110 can be a dipping method, various printing methods such as screen printing, an application method using a dispenser, a spraying method using a spray, etc. The sintered metal layer forming paste is applied to at least the third and fourth surfaces of the capacitor body 110, and is selectively applied to a part of the first, second, fifth or sixth surface on which the band portions of the first and second external electrodes are formed.

[0136] Thereafter, the capacitor body 110 on which the paste for forming a sintered metal layer is applied is dried and sintered at a temperature of 700° C. to 1000° C. for 0.1 to 3 hours to form a sintered metal layer.

[0137] Alternatively, a conductive resin layer forming paste may be applied to the outer surface of the obtained capacitor body 110 and then cured to form a conductive resin layer.

[0138] The paste for forming the conductive resin layer may include a resin, and optionally a conductive metal or a non-conductive filler. The conductive metal and the resin have been described above, and therefore will not be described again. The paste for forming the conductive resin layer may optionally include a binder, a solvent, a dispersant, a plasticizer, an oxide powder, and the like. Examples of the binder include ethyl cellulose, acrylic, butyral, and the like, and examples of the solvent include organic solvents or aqueous solvents such as terpineol, butyl carbitol, alcohol, methyl ethyl ketone, acetone, and toluene.

[0139] As an example, the conductive resin layer may be formed by dipping the capacitor body 110 in a paste for forming the conductive resin layer and then curing it, or by printing the paste for forming the conductive resin layer on the surface of the capacitor body 110 using a screen printing method or a gravure printing method, or by applying the paste for forming the conductive resin layer on the surface of the capacitor body 110 and then curing it.

[0140] Next, a plating layer is formed on the outer side of the conductive resin layer. As an example, the plating layer is formed by a plating method, and may be formed by sputtering or electric deposition.

[0141] The above-mentioned embodiments will be described in more detail with reference to the following examples, which are merely for illustrative purposes and are not intended to limit the scope of the invention.

[0142] (Manufacturing multilayer ceramic capacitors) Example 1 BaTiO 3 Powder, Ga 2 O 3 The powder and polyvinyl butyral resin were mixed to prepare a coating composition. 2 O 3 The powder is BaTiO 3 The powder was mixed at 3 mol parts per 100 mol parts, and the binder was mixed at 50 wt % based on the total amount of the coating composition. 3 A margin sheet having an adhesive surface was prepared by applying the above-mentioned solution to one side of the margin sheet.

[0143] BaTiO 3 Powder was used to make zirconium balls (ZrO 2 A dielectric slurry was prepared by mechanically milling a mixture of ethanol / toluene, a wetting dispersant, and polyvinyl butyral (PVB) resin as a binder, using a ferromagnetic ball as a dispersion medium.

[0144] The prepared dielectric slurry was used in a head-discharging on-roll forming coater to prepare a dielectric green sheet. A conductive paste layer containing nickel (Ni) was printed on the surface of the dielectric green sheet, and the dielectric green sheets (width x length x height = 3.2 mm x 2.5 mm x 2.5 mm) on which the conductive paste layer was formed were laminated and pressed to prepare a dielectric green sheet laminate.

[0145] The dielectric green sheet laminate was cut in a state where the conductive paste layer was exposed without leaving any area where the conductive paste layer was not printed. The margin sheet having the adhesive surface was bonded to the cut surface of the cut dielectric green sheet laminate.

[0146] The dielectric green sheet laminate with the margin sheet bonded is subjected to a plasticization process at 400°C or less in a nitrogen atmosphere, and then sintered at a temperature of 1300°C or less and with a hydrogen concentration of 1.0% H 2 The firing was carried out under the following conditions: Next, a multilayer ceramic capacitor was manufactured through processes such as forming external electrodes and plating.

[0147] Example 2 In Example 1, the Ga 2 O 3 The powder was BaTiO 3 A multilayer ceramic capacitor was manufactured in the same manner as in Example 1, except that 6 parts by mole of the powder was mixed with 100 parts by mole of the powder.

[0148] Comparative Example 1 In Example 1, the Ga 2 O 3 A multilayer ceramic capacitor was produced in the same manner as in Example 1, except that no powder was used.

[0149] Evaluation 1: SEM-EDS analysis The multilayer ceramic capacitors manufactured in Examples 1 and 2 were subjected to SEM-EDS (scanning electron microscope-energy dispersive spectroscopy) analysis to confirm the presence and content of gallium (Ga) at each position, and the results are shown in FIGS. 5A and 5B. The SEM-EDS analysis was performed in the following manner.

[0150] The multilayer ceramic capacitor 100 manufactured in Examples 1 and 2 was put into an epoxy mixture and cured, and then the W-axis and T-axis directions (WT directions) of the capacitor body 110 were polished to 1 / 2 points in the L-axis direction, and then fixed and maintained in a vacuum atmosphere chamber to obtain a cross-sectional sample so that the active part where the dielectric layer 111 and the internal electrode layers 121 and 122 intersect and the side margin part can be observed. Next, the cross-sectional sample having the WT direction was divided in half in the width (W-axis) direction, and one side margin part and the active part were measured with a scanning electron microscope (SEM). For the SEM, for example, a Verios G4 product from Thermofisher Scientific was used, and the measurement conditions were 10 kV, 0.2 nA, and analysis magnification 10 k times, and the measurement was performed so that at least 10 layers of the dielectric layer 111 and the internal electrode layers 121 and 122 were exposed.

[0151] Next, EDS (energy dispersive spectroscopy) analysis was performed on the SEM image of the measured cross-sectional sample. In the EDS analysis, the side margin was divided into two equal parts in the width direction in the SEM image of the measured cross-sectional sample, and the area closer to the junction was defined as the first side margin, and the remaining area was divided into the second side margin. In addition, in the active part, the boundary vicinity area was defined as a point having a length from the boundary surface with the junction to a point having a length equivalent to two to three times the width direction length of the side margin, and the boundary vicinity area of ​​the active part was divided into two equal parts in the width direction, and the area closer to the junction was defined as the first active part, and the remaining area was divided into the second active part. Here, the content of gallium (Ga) was measured at one point each of the first side margin, the second side margin, the first active part, and the second active part.

[0152] FIG. 5A is a graph showing the gallium (Ga) content by position in the multilayer ceramic capacitor according to Example 1, and FIG. 5B is a graph showing the gallium (Ga) content by position in the multilayer ceramic capacitor according to Example 2.

[0153] 5A and 5B, in Examples 1 and 2 according to an embodiment, at least one of the active portion (sites 1 and 2) and the side margin portion (sites 3 and 4) contains gallium (Ga). Also, it can be seen that the content of gallium (Ga) in the first side margin portion (site 3) is 0.7 parts by weight in Example 1 and 0.8 parts by weight in Example 2, calculated based on 100 parts by weight of barium (Ba). Furthermore, it can be seen that the content of gallium (Ga) is higher in the first side margin portion (site 3) than in the second side margin portion (site 4).

[0154] Evaluation 2: SEM analysis The multilayer ceramic capacitors manufactured in Examples 1 and 2 and Comparative Example 1 were subjected to SEM (scanning electron microscope) analysis to confirm the porosity generation rate at the end portions of the internal electrode layers, and the results are shown in FIGS. 6A to 6C.

[0155] First, the SEM analysis was performed as follows. The multilayer ceramic capacitor 100 manufactured in Examples 1 and 2 and Comparative Example 1 was put into an epoxy mixture and cured, and then the W-axis and T-axis directions (WT directions) of the capacitor body 110 were polished to 1 / 2 points in the L-axis direction, and after fixing, the sample was maintained in a vacuum atmosphere chamber to obtain a cross-sectional sample so that the active part and side margin parts where the dielectric layer 111 and the internal electrode layers 121 and 122 intersect were observed. Next, the cross-sectional sample having the WT direction was divided in half in the width (W-axis) direction, and one side margin part and the active part were measured with a scanning electron microscope (SEM) so that the end of the internal electrode layer, in particular, could be clearly seen. For example, a Verios G4 product from Thermofisher Scientific was used as the SEM, and the measurement conditions were 2 kV, 0.2 nA, and analysis magnification 10 k times, and the measurement was performed so that at least 20 layers of the dielectric layer 111 and the internal electrode layers 121 and 122 could be seen.

[0156] From the SEM image of the measured cross-sectional sample, the porosity rate at the end of the internal electrode layer was obtained by the following Equation 1. [Formula 1] Porosity occurrence rate (%) of the end part of the internal electrode layer = (number of internal electrode layers having pores at the end part / total number of internal electrode layers) x 100

[0157] FIG. 6A is an SEM image showing pore formation at the end portions of the internal electrode layers in the multilayer ceramic capacitor according to Example 1, FIG. 6B is an SEM image showing pore formation at the end portions of the internal electrode layers in the multilayer ceramic capacitor according to Example 2, and FIG. 6C is an SEM image showing pore formation at the end portions of the internal electrode layers in the multilayer ceramic capacitor according to Comparative Example 1.

[0158] 6A to 6C, the porosity rates of the terminations of the internal electrode layers in Examples 1 and 2 are 39% and 27%, respectively, while the rate is 78% in Comparative Example 1. This shows that the multilayer ceramic capacitor according to an embodiment, in which at least one of the active section and the side margin section contains gallium (Ga), has excellent termination density of the internal electrode layers. This improves the moisture resistance reliability and the withstand voltage characteristics.

[0159] Rating 3: Moisture resistance reliability The multilayer ceramic capacitors manufactured in Examples 1 and 2 and Comparative Example 1 were measured for moisture resistance reliability, and the results are shown in FIGS. 7A to 7C.

[0160] Specifically, 80 multilayer ceramic capacitors each manufactured in Examples 1 and 2 and Comparative Example 1 were prepared and mounted on a measurement board, and measured using an ESPEC (PR-3J, 8585) device under conditions of 85°C, relative humidity (RH) 85%, 6.3 V, and 8 hours.

[0161] FIG. 7A is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Example 1, FIG. 7B is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Example 2, and FIG. 7C is a graph showing the moisture resistance reliability of the multilayer ceramic capacitor according to Comparative Example 1.

[0162] 7A to 7C, it can be seen that in Examples 1 and 2 in which gallium (Ga) is contained in at least one of the active portion and the side margin portion according to one embodiment, the moisture resistance reliability is superior to that of Comparative Example 1.

[0163] Although the preferred embodiment of the present invention has been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the description of the invention, and the accompanying drawings, which of course also fall within the scope of the present invention. [Explanation of symbols]

[0164] 100: Multilayer ceramic capacitor 110: Capacitor body 111: Dielectric layer 121: 1st internal electrode 122:Second internal electrode 131: 1st external electrode 132:Second external electrode 10: Active section 15, 15': Boundary region 16, 16': First active section 17, 17': Second active section 20, 20': Side margin 21, 21': First side margin 22, 22': Second side margin 30, 30': Joint

Claims

1. a capacitor body including a dielectric layer and an internal electrode layer; an external electrode disposed on an outer side of the capacitor body; The capacitor body includes: an active section in which the dielectric layers and the internal electrode layers are alternately arranged; side margin portions disposed on both opposing ends of the active portion; a joint portion disposed between the active portion and the side margin portion, At least one of the active section and the side margin section is a multilayer ceramic capacitor containing a barium titanate-based main component including barium (Ba) and titanium (Ti), and containing gallium (Ga).

2. 2. The multilayer ceramic capacitor according to claim 1, wherein the barium titanate-based main component and the gallium (Ga) are contained in the side margin portion.

3. When the side margin portion is divided into two equal parts in the width direction, the region closest to the joint portion is defined as a first side margin portion, and the remaining region is defined as a second side margin portion, The multilayer ceramic capacitor according to claim 2 , wherein the gallium (Ga) is contained in the first side margin portion.

4. 4. The multilayer ceramic capacitor according to claim 3, wherein the gallium (Ga) is contained in the first side margin portion in an amount of more than 0 parts by weight to 1.5 parts by weight or less with respect to 100 parts by weight of the barium (Ba).

5. The gallium (Ga) is included in the first side margin portion and the second side margin portion, 4. The multilayer ceramic capacitor according to claim 3, wherein the gallium (Ga) is contained in a higher content in the first side margin portion than in the second side margin portion.

6. The multilayer ceramic capacitor according to claim 1 , wherein the barium titanate-based main component and the gallium (Ga) are contained in the active portion.

7. the active portion includes a boundary vicinity region defined as a region extending from a boundary surface with the joint portion to a point having a length equivalent to two to three times the width direction length of the side margin portion, The multilayer ceramic capacitor according to claim 6 , wherein the gallium (Ga) is contained in a region near the boundary of the active section.

8. When the boundary vicinity region of the active section is divided into two equal parts in the width direction, the region closer to the joint is defined as a first active section, and the remaining region is defined as a second active section, the gallium (Ga) is included in the first active portion and the second active portion; The multilayer ceramic capacitor of claim 7 , wherein the gallium (Ga) is contained in a higher content in the first active portion than in the second active portion.

9. 2. The multilayer ceramic capacitor according to claim 1, wherein the barium titanate-based main component and the gallium (Ga) are contained in the side margin portion and the active portion.

10. The multilayer ceramic capacitor according to claim 9 , wherein the gallium (Ga) is contained in a higher content in the side margin portion than in the active portion.

11. 2. The multilayer ceramic capacitor according to claim 1, wherein the joint portion contains a barium titanate-based compound containing barium (Ba) and Ti (titanium), and gallium (Ga).

12. 12. The multilayer ceramic capacitor according to claim 11, wherein the gallium (Ga) is contained in the joint in an amount of 0.3 parts by weight to 1.5 parts by weight per 100 parts by weight of the barium (Ba).

13. 2. The multilayer ceramic capacitor according to claim 1, wherein a porosity rate of an end portion of an internal electrode layer, which is obtained by the following Equation 1 with respect to a joint surface between the active portion and the joint portion, is more than 0% to 40%: [Formula 1] Porosity occurrence rate (%) of end portion of internal electrode layer=(number of internal electrode layers having pores at end portion / total number of internal electrode layers)×100

14. A step of preparing a margin sheet having an adhesive surface by applying a coating composition containing a barium titanate compound and gallium (Ga) to at least one surface of the margin sheet; preparing a dielectric green sheet using the dielectric slurry and forming a conductive paste layer on a surface of the dielectric green sheet; laminating the dielectric green sheets having the conductive paste layers formed thereon to manufacture a dielectric green sheet laminate; cutting the dielectric green sheet laminate in a state where the conductive paste layer is exposed without leaving any area where the conductive paste layer is not formed; bonding the margin sheet having the adhesive surface to a cut surface of the cut dielectric green sheet laminate; sintering the dielectric green sheet laminate to which the margin sheet is bonded to manufacture a capacitor body; forming an external electrode on one surface of the capacitor body; the capacitor body includes an active section in which dielectric layers and internal electrode layers are alternately arranged, side margin sections arranged on both opposing ends of the active section, and a joint section arranged between the active section and the side margin sections, A method for manufacturing a multilayer ceramic capacitor, wherein at least one of the active section and the side margin section contains a barium titanate-based main component containing barium (Ba) and Ti (titanium), and gallium (Ga).

15. The method for manufacturing a multilayer ceramic capacitor according to claim 14, wherein the coating composition contains gallium (Ga) in an amount of more than 0 to 6 parts by mol per 100 parts by mol of the barium titanate-based compound.

16. The method for producing a multilayer ceramic capacitor according to claim 14, wherein the gallium (Ga) is contained 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.

17. The method for producing a multilayer ceramic capacitor according to claim 14 , wherein the coating composition further comprises a binder.

Images