Dielectric composition, multilayer capacitor, and method for manufacturing multilayer capacitor

Abstract

The present disclosure provides a dielectric composition, a multilayer capacitor, and a method of manufacturing the multilayer capacitor. The dielectric composition includes: a dielectric crystal grain including a barium titanate-based compound; and a second phase between the dielectric grains, and the second phase includes a first second phase including Ga and Si. The multilayer capacitor includes: a capacitor body including a dielectric layer and an inner electrode; and an external electrode disposed outside the capacitor body, in which the dielectric layer includes the dielectric composition described above.

Description

Technical Field

[0001] The present disclosure relates to a dielectric composition, a multilayer capacitor including the dielectric composition, and a method for manufacturing the multilayer capacitor. Background Art

[0002] In recent years, with the rapid development of multifunctionalization and miniaturization of electronic devices, the miniaturization and performance improvement of electronic components are also developing rapidly. In addition, the demand for high reliability of electronic components used in automobiles or network equipment and electronic components used for industrial purposes has increased significantly.

[0003] In order to meet such market demands, the competition for the technical development of passive components such as inductors, capacitors or resistors is accelerating. In particular, as the use and usage of multilayer ceramic capacitors (MLCCs) (as passive components) continue to increase, more efforts need to be made to seize the market.

[0004] In addition, multilayer ceramic capacitors, which are capacitors manufactured in the form of dielectric layers and internal electrodes stacked in layers, are used in various electronic devices such as mobile phones, laptop computers, and LCD TVs. As electronic devices become smaller and more functional, miniaturization and thinning of multilayer capacitors are required.

[0005] As multilayer ceramic capacitors become smaller and thinner, phenomena such as degradation of the internal voltage characteristics of the capacitor, reduced reliability, and reduced dielectric constant occur, and in order to solve these problems, it is necessary to reduce the sintering temperature when manufacturing multilayer ceramic capacitors. However, reducing the sintering temperature leads to reduced density of the dielectric layer and degradation of the reliability of the dielectric layer. Summary of the invention

[0006] One aspect of the embodiments provides a dielectric composition that improves density (reduces porosity) by lowering the sintering temperature of the dielectric.

[0007] Another aspect of the present embodiment provides a multilayer capacitor including a dielectric composition having enhanced dielectric characteristics and moisture resistance reliability.

[0008] However, the problems to be solved by the embodiments of the present disclosure are not limited to the above-mentioned problems, but can be expanded in various ways within the scope of the technical spirit included in the embodiments.

[0009] A dielectric composition according to an embodiment includes: dielectric grains including a barium titanate-based compound; and a second phase located between the dielectric grains, and the second phase includes a first second phase including Ga and Si.

[0010] The dielectric grains including the barium titanate-based compound may be a main phase, an average area of ​​the main phase may be 85% or more of a total area of ​​the dielectric composition, and an average area of ​​the second phase may be 15% or less of a total area of ​​the dielectric composition.

[0011] The first second phase may further include Al and / or Mg.

[0012] The first second phase may include Si in an amount of 1.0 to 3.0 parts by mole, Al in an amount of 0.5 to 2.5 parts by mole, and Mg in an amount of 0.2 to 1.2 parts by mole, relative to 1 part by mole of Ga.

[0013] An average area (%) occupied by the first second phase may be 50% to 95% with respect to a total area of ​​the second phase.

[0014] The second phase may further include a second second phase including Si and not including Ga, and an average area (%) occupied by the second second phase may be 5% to 50% with respect to a total area of ​​the second phase.

[0015] A ratio of an average area occupied by the first second phase relative to a total area of ​​the second phase to an average area occupied by the second second phase relative to a total area of ​​the second phase may be 1.5 to 2.5.

[0016] The dielectric composition may include Ga in an amount of 0.1 wt % to 0.5 wt % based on the total weight of all components of the dielectric composition.

[0017] According to another embodiment, a multilayer capacitor includes: a capacitor body including a dielectric layer and an inner electrode; and an outer electrode arranged outside the capacitor body, wherein the dielectric layer includes dielectric grains and a second phase located between the dielectric grains, the dielectric grains include a barium titanate-based compound, and the second phase includes a first second phase containing Ga and Si.

[0018] The dielectric grains including the barium titanate-based compound may be a main phase, an average area of ​​the main phase may be 85% or more of a total area of ​​the dielectric layer, and an average area of ​​the second phase may be 15% or less of a total area of ​​the dielectric layer.

[0019] The first second phase may further include Al and / or Mg.

[0020] The first second phase may include Si in an amount of 1.0 to 3.0 parts by mole, Al in an amount of 0.5 to 2.5 parts by mole, and Mg in an amount of 0.2 to 1.2 parts by mole, relative to 1 part by mole of Ga.

[0021] An average area (%) occupied by the first second phase may be 50% to 95% with respect to a total area of ​​the second phase.

[0022] The second phase may further include a second second phase including Si and not including Ga, and an average area (%) occupied by the second second phase may be 5% to 50% with respect to a total area of ​​the second phase.

[0023] A ratio of an average area occupied by the first second phase relative to a total area of ​​the second phase to an average area occupied by the second second phase relative to a total area of ​​the second phase may be 1.5 to 2.5.

[0024] The dielectric layer may include Ga in an amount of 0.1 wt % to 0.5 wt % based on the total weight of all components of the dielectric layer.

[0025] According to another embodiment, a method for manufacturing a multilayer capacitor includes: manufacturing a dielectric powder including gallium (Ga), wherein the manufacturing of the dielectric powder including gallium (Ga) includes adding gallium (Ga) having an average particle size of 1 nm to 15 nm to a precursor of a barium titanate-based dielectric; manufacturing a dielectric green sheet by using the dielectric powder, and forming a conductive paste layer on a surface of the dielectric green sheet; manufacturing a dielectric green sheet stack by stacking a plurality of the dielectric green sheets, wherein the conductive paste layer is formed on each of the plurality of dielectric green sheets; manufacturing a capacitor body including a dielectric layer and an inner electrode by sintering the dielectric green sheet stack; and forming an outer electrode on an outer surface of the capacitor body.

[0026] The sintering temperature for sintering the dielectric green sheet stack may be 1000°C to 1200°C.

[0027] A dielectric composition according to an embodiment includes: dielectric grains including a barium titanate-based compound; and a second phase located between the dielectric grains, the second phase including a first second phase and a second second phase, the first second phase including Ga and Si, the second second phase including Si and not including Ga.

[0028] The dielectric composition may be free of rare earth elements.

[0029] The first second phase may further include Al and / or Mg.

[0030] The first second phase may include Si in an amount of 1.0 to 3.0 parts by mole, Al in an amount of 0.5 to 2.5 parts by mole, and Mg in an amount of 0.2 to 1.2 parts by mole, relative to 1 part by mole of Ga.

[0031] The dielectric composition may include Ga in an amount of 0.1 wt % to 0.5 wt % based on the total weight of all components of the dielectric composition.

[0032] According to another embodiment, a multilayer capacitor includes: a capacitor body, including a dielectric layer and an inner electrode; and an outer electrode, arranged outside the capacitor body, wherein the dielectric layer includes dielectric grains and a second phase located between the dielectric grains, the dielectric grains include a barium titanate-based compound, and the second phase includes a first second phase and a second second phase, the first second phase includes Ga and Si, and the second second phase includes Si and does not contain Ga.

[0033] The dielectric layer may not contain rare earth elements, the dielectric grains including the barium titanate-based compound may be a main phase, the average area of ​​the main phase may be 85% or more of the total area of ​​the dielectric layer, and the average area of ​​the second phase may be 15% or less of the total area of ​​the dielectric layer.

[0034] The first second phase may further include Al and / or Mg.

[0035] The first second phase may include Si in an amount of 1.0 to 3.0 parts by mole, Al in an amount of 0.5 to 2.5 parts by mole, and Mg in an amount of 0.2 to 1.2 parts by mole, relative to 1 part by mole of Ga.

[0036] The dielectric layer may include Ga in an amount of 0.1 wt % to 0.5 wt % based on the total weight of all components of the dielectric layer, the average area (%) occupied by the first second phase relative to the total area of ​​the second phase may be 50 % to 95 %, and the average area (%) occupied by the second second phase may be 5 % to 50 % relative to the total area of ​​the second phase.

[0037] With the dielectric composition according to the embodiment, since the compactness is improved (the porosity is reduced) by lowering the sintering temperature of the dielectric, there is an advantage of improving the dielectric characteristics and moisture resistance reliability of the multilayer capacitor.

[0038] However, various beneficial advantages and effects of the present disclosure are not limited to the above contents and can be more easily understood in the process of describing specific embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1A An image obtained by observing the dielectric composition according to the example using a transmission electron microscope (TEM) is shown.

[0040] Figure 1B An image obtained by TEM mapping of Ga-based dielectric compositions is shown.

[0041] Figure 1C An image obtained by TEM mapping of a Si-based dielectric composition is shown.

[0042] Figure 1D An image obtained by TEM mapping of an Al-based dielectric composition is shown.

[0043] Figure 1E An image obtained by TEM mapping of a dielectric composition based on Mg is shown.

[0044] Figure 2A An image obtained by performing TEM mapping on the dielectric composition according to the embodiment based on Ga is shown. Figure 2B The results obtained by TEM-EDS analysis are shown in Figure 2A Graph showing the Ga content in region 1 and region 2.

[0045] Figure 3A An image obtained by observing the dielectric composition according to the example using TEM is shown. Figure 3B An image showing the entire region of the second phase included in the dielectric composition is shown. Figure 3C An image showing a region of a second secondary phase included in the dielectric composition is shown.

[0046] Figure 4A An image obtained by observing the dielectric composition according to the example using SEM is shown. Figure 4B is a graph showing the contents of constituent components included in a dielectric composition.

[0047] Figure 5 : is a graph analyzing the content of the second phase constituent component of the dielectric composition included in the multilayer capacitors in Example 1 and Comparative Example 2.

[0048] Figure 6 is a graph showing the sintered density of the dielectric compositions prepared in Preparation Example 1 and Comparative Preparation Examples 1 and 2 for each sintering temperature.

[0049] FIG. 7A to FIG. 7L SEM images showing the densification levels of the dielectric compositions included in the multilayer capacitors in Example 1 and Comparative Examples 1 and 2 according to sintering temperatures are shown.

[0050] Fig. 8A A SEM image of a cross-sectional sample of the multilayer capacitor in Comparative Example 1 is shown. Figure 8B A SEM image of a cross-sectional sample of the multilayer capacitor in Example 1 is shown.

[0051] Fig. 9is a graph showing the dielectric constants of the multilayer capacitors in Example 1 and Comparative Examples 1 and 2 for each temperature.

[0052] Figures 10 to 12 Graphs showing evaluation of moisture resistance reliability of the multilayer capacitors in Example 1 and Comparative Examples 1 and 2, respectively.

[0053] Fig.13 is a perspective view showing a multilayer capacitor according to an embodiment.

[0054] Fig.14 is along Fig.13 A cross-sectional view of the multilayer capacitor taken along line II'.

[0055] Fig.15 It is shown Fig.13 An exploded perspective view of the laminated structure of the capacitor body. DETAILED DESCRIPTION

[0056] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings so that those skilled in the art can easily implement the present disclosure. The drawings and descriptions are considered to be illustrative rather than restrictive in nature. Throughout the specification, the same figure numerals represent the same elements. In addition, the drawings are provided to help easily understand the embodiments disclosed in this specification, and the technical spirit disclosed in this specification is not limited by the drawings, and it should be understood that the present disclosure includes all variations, equivalents and alternatives that fall within the spirit and technical scope of the present disclosure. In addition, some of the constituent elements in the drawings may be exaggerated, omitted or schematically shown, and the size of each constituent element does not fully reflect the actual size.

[0057] In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “including” or “having”, will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

[0058] Throughout the specification, the "stacking direction" may be the direction in which the components are stacked sequentially, and may also be the "thickness direction" perpendicular to the wide surface of the sheet-like component, and corresponds to the T-axis direction in the drawings. In addition, the "length direction" is the direction parallel to the long side of the wide surface of the sheet-like component, and may correspond to the L-axis direction in the drawings. In addition, the W-axis direction in the drawings may be the "width direction", and may be the direction parallel to the wide side of the wide surface of the sheet-like component.

[0059] Hereinafter, various examples and modified examples will be described with reference to the drawings.

[0060] Dielectric composition

[0061] The dielectric composition includes dielectric grains containing a barium titanate-based compound and a second phase located between the dielectric grains, and the second phase includes a first second phase containing Ga and Si.

[0062] As an example, the dielectric grains containing a barium titanate-based compound can be the main phase, and the average area of the main phase is 85% or more of the total area of the dielectric composition.

[0063] As an example, the second phase may further include a second second phase that does not include (excludes) Ga and includes Si.

[0064] The dielectric composition according to the embodiment includes a first second phase for reducing the sintering temperature when sintering the dielectric composition and improving the densification (reducing the porosity) to enhance the dielectric properties and reliability of the multilayer capacitor including the dielectric composition.

[0065] The main phase is a concept different from the second phase and can refer to the main phase constituting the dielectric composition generated during the process of sintering the capacitor body 110.

[0066] The main phase may include a main component and a sub-component.

[0067] The main component as the matrix material of the dielectric has a high dielectric constant and contributes to the dielectric constant of the multilayer capacitor 100.

[0068] As an example, the main component may include a barium titanate-based material, and as an example, the barium titanate-based material may include Ba m TiO3 (0.995 ≤ m ≤ 1.010), (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba m (Ti 1-x Zr x )O3 (0.995 ≤ m ≤ 1.010, 0 < x ≤ 0.10), (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20) or a combination thereof.

[0069] As an example, the main component may include BaTiO3, Ba(Ti ,Zr)O3, Ba(Ti,Sn)O3, (Ba,Ca)TiO3, (Ba,Ca)(Ti,Zr)O3, (Ba,Ca)(Ti,Sn)O3, (Ba,Sr)TiO3, (Ba,Sr)(Ti,Zr)O3, (Ba,Sr)(Ti,Sn)O3 or combinations thereof.

[0070] As examples, the secondary components may include dysprosium (Dy), vanadium (V), 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 (Cc), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), or combinations thereof.

[0071] As an example, a dielectric composition may include a plurality of dielectric grains.

[0072] The dielectric grains may be a main phase, and at least one of the plurality of dielectric grains may have a core-shell structure.

[0073] The dielectric grain having a core-shell structure includes a core located inside one dielectric grain and a shell surrounding at least a portion of the core.

[0074] Core and shell can have different secondary components and the molar ratio of main component, for example, the molar ratio of secondary components and main component can change rapidly at the boundary of core and shell.Therefore, the boundary of core and shell can be easily distinguished, and this can be confirmed by transmission electron microscope-energy dispersive X-ray spectrometer (TEM-EDS).

[0075] As an example, in the core, there is no secondary component, or even if there is a secondary component, there may be only a small amount of the secondary component. Therefore, the core may be made of a pure main component containing no impurities, and the pure main component may have a higher dielectric constant than the main component doped with an impurity element. Therefore, the core may play a role in improving the dielectric constant.

[0076] The shell includes more secondary components than the core. The secondary components doped in the B site of the main component (perovskite ABO3 structure) in the shell have the effect of increasing the band gap energy in which other rare earth elements and doping elements are dispersed into the dielectric grains. Therefore, the secondary components can be used as a barrier to inhibit the dispersion of other rare earth elements and doping elements into the dielectric grains. The shell is used to inhibit the growth of dielectric grains to facilitate the granulation of dielectric grains. In addition, the secondary components doped in the A site of the main component in the shell can be used to improve reliability and dielectric constant.

[0077] The second phase may mean a “second phase”, and means a new phase precipitated after the capacitor body 110 is sintered.

[0078] The secondary phase may be located between dielectric grains including the barium titanate-based compound constituting the primary phase.

[0079] The second phase may include the first second phase and further include the second second phase.

[0080] The first second phase may include Ga and Si, and may further include Al and / or Mg.

[0081] As an example, the first second phase may include a combination of Ga and Si with Al and / or Mg, and as a specific example, the first second phase may be a Ga composite form in which Ga, Si, Al, and Mg are chemically combined.

[0082] The second second phase may include Si but not Ga. The second second phase may include Si, and may further include Al and / or Mg. The second second phase may be a Si compound, or a Si composite form in which Si, Al, and Mg are chemically combined.

[0083] The first second phase or the second second phase may further include Ti, V, Mn, Ba, or a combination thereof.

[0084] Additionally, the dielectric composition may be free of rare earth elements.

[0085] Figure 1A An image obtained by observing the dielectric composition according to the example using a transmission electron microscope (TEM) is shown. Figure 1B An image obtained by TEM mapping of Ga-based dielectric compositions is shown. Figure 1C An image obtained by TEM mapping of a Si-based dielectric composition is shown. Figure 1D An image obtained by TEM mapping of an Al-based dielectric composition is shown. Figure 1E An image obtained by TEM mapping of a dielectric composition based on Mg is shown.

[0086] Reference Figure 1A , by distinguishing portions with brightness difference to distinguish the main phase from the second phase by a method such as binarization of the TEM image, the relatively dark region may correspond to the second phase. As an example, the second phase may be located outside the dielectric grains of the main phase, for example, the second phase may be located on the boundary between the dielectric grains of the main phase.

[0087] Reference Figures 1B to 1E , the light gray area indicates the presence of the element of interest, and the second phase containing Ga can be defined as the first second phase, and it can be seen that Si, Al and Mg are composited with the first second phase. Figure 1B and Figure 1C , in the second phase including Si, the second phase not including Ga can be defined as a second second phase.

[0088] Figure 2A An image obtained by performing TEM mapping on the dielectric composition according to the embodiment based on Ga is shown, and a region 1 shown in the image represents a first second phase, and a region 2 shown in the image represents a second second phase.

[0089] Figure 2B The results obtained by TEM-EDS analysis are shown in Figure 2A Graph showing the Ga content in region 1 and region 2.

[0090] Reference Figure 2B , it can be seen that Ga is contained in the first second phase, while Ga is not contained in the second second phase.

[0091] In an embodiment, the first second phase may include Si in an amount of 1.0 to 3.0 mol parts, for example, 1.5 to 3.0 mol parts or 1.5 to 2.5 mol parts, relative to 1 mol parts of Ga.

[0092] In an embodiment, the first second phase may include Al in an amount of 0.5 to 2.5 mol parts, for example, 1.0 to 2.5 mol parts or 1.0 to 2.0 mol parts, relative to 1 mol part of Ga.

[0093] In an embodiment, the first second phase may include Mg in an amount of 0.2 to 1.2 mol parts, for example, 0.2 to 1.0 mol parts or 0.4 to 1.0 mol parts, relative to 1 mol parts of Ga.

[0094] When the contents of the constituent elements contained in the first and second phases satisfy the above numerical ranges, the sintering temperature of the dielectric composition is sufficiently lowered to significantly improve the compactness (reduce the porosity).

[0095] In the multilayer capacitor 100, the contents (mol) of the constituent elements included in the first and second phases can be obtained by the following method.

[0096] The multilayer capacitor 100 according to the embodiment is placed in an epoxy mixture and cured, and then the L-axis and T-axis sides of the capacitor body 110 are polished to 1 / 2 in the W-axis direction, and fixed and maintained in a vacuum atmosphere to prepare a cross-sectional sample cut along the L-axis and T-axis directions at the center of the capacitor body 110 in the W-axis direction.

[0097] Then, an arbitrary dielectric layer located in the active region or the cover region of the cross-sectional sample was selected, and then a transmission electron microscope (TEM) image was obtained in an area of ​​5 μm×5 μm (unit area).

[0098] For TEM images, mapping images of each element of Ga, Si, Al and Mg are obtained by using a transmission electron microscope-energy dispersive X-ray spectrometer (TEM-EDS), and then any first and second phases containing Ga are selected to perform content analysis of each element. After measuring the content of each element in mol, the content (mol) of Ga, Si, Al and Mg can be expressed as a relative value based on 1 mol of Ga. Even if not described in the present disclosure, other methods and / or tools known to those of ordinary skill in the art can also be used.

[0099] Figure 3A An image obtained by observing the dielectric composition according to the example using TEM is shown. Figure 3B An image showing the entire region (colored region) of the second phase included in the dielectric composition is shown. Figure 3C An image showing a region (colored region) of a second secondary phase included in the dielectric composition is shown.

[0100] Reference FIG. 3A to FIG. 3C , the dielectric grains including the barium titanate-based compound may be a main phase having an average area of ​​85% or more of the total area of ​​the dielectric composition, and the average area of ​​the secondary phase having an average area of ​​15% or less of the total area of ​​the dielectric composition.

[0101] Reference FIG. 3A to FIG. 3C Relative to the area of ​​the second phase (eg, total area), the average area (%) occupied by the first second phase may be 50% to 95%, for example, 50% to 90% or 50% to 80%.

[0102] The average area (%) occupied by the second phase may be 5% to 50%, for example, 10% to 50% or 20% to 50%, relative to the area (eg, total area) of the second phase.

[0103] A ratio of an average area of ​​the first second phase relative to a total area of ​​the second phases to an average area of ​​the second second phase relative to the total area of ​​the second phases may be 1.5 to 2.5.

[0104] When the average area (%) occupied by the first second phase and the second second phase relative to all second phases and the ratio of the average area of ​​the first second phase and the second second phase satisfy the above numerical ranges, the sintering temperature of the dielectric composition is sufficiently reduced to significantly improve the density (reduce the porosity).

[0105] In the multilayer capacitor 100 according to the embodiment, a method for obtaining the average area (%) of the main phase and the second phase relative to the total area of ​​the dielectric composition, the average area (%) occupied by the first second phase and the second second phase relative to the area of ​​the second phase, and the ratio of the average areas of the first second phase and the second second phase is described below.

[0106] First, prepare a cross-sectional sample of the above-mentioned multilayer capacitor, select any dielectric layer located in the effective area or the coverage area of ​​the cross-sectional sample, and then obtain a transmission electron microscope (TEM) image in an area of ​​5μm×5μm. Then, the area of ​​the main phase and the second phase and the area of ​​the first second phase and the second second phase included in the second phase can be measured by using an image analysis program. In addition, the arithmetic mean of the values ​​measured in three or more areas with a size of 5μm×5μm is obtained to obtain the average area of ​​the main phase and the second phase and the average area (%) occupied by the first second phase and the second second phase relative to all second phases. In addition, the ratio between the average area (%) of the above-mentioned first second phase and the second second phase can be obtained. Even if not described in the present disclosure, other methods and / or tools known to those of ordinary skill in the art may be used.

[0107] In an embodiment, for example, based on the total weight of all components of the dielectric composition, the content of Ga may be 0.1 wt % to 1.0 wt %. For example, based on the total weight of all components of the dielectric composition, the content of Ga may be 0.1 wt % to 0.5 wt %.

[0108] Figure 4A An image obtained by observing the dielectric composition according to the example using SEM is shown. Figure 4B is a graph showing the contents of constituent components included in a dielectric composition.

[0109] Reference Figure 4A and Figure 4B , any dielectric layer located in the active area or the covering area of ​​the cross-sectional sample can be selected, and then a scanning electron microscope (SEM) image can be obtained, and the Ga content in the entire dielectric composition can be measured by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) composition analysis.

[0110] Multilayer capacitors

[0111] The multilayer capacitor 100 according to the embodiment includes a capacitor body 110 including a dielectric layer 111 and internal electrodes 121 and 122 , and external electrodes 131 and 132 disposed outside the capacitor body 110 , and the dielectric layer 111 includes a dielectric composition.

[0112] Fig.13 is a perspective view showing a multilayer capacitor according to an embodiment, Fig.14 is along Fig.13 A cross-sectional view of the multilayer capacitor taken along line II', and Fig.15 It is shown Fig.13 An exploded perspective view of the laminated structure of the capacitor body.

[0113] When defining directions for the purpose of clearly describing the present embodiment, the L axis, the W axis, and the T axis represent the length direction, the width direction, and the thickness direction of the capacitor body 110, respectively. Here, the thickness direction (T axis direction) may be a direction perpendicular to the wide surface of the sheet component, and as an 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) as a direction parallel to the long side of the wide surface of the sheet component may be a direction substantially perpendicular to the thickness direction (T axis direction), and 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 opposite to each other. The width direction (W axis direction) may be a direction substantially perpendicular to the thickness direction (T axis direction) and the length direction (L axis direction), and the length of the sheet component in the length direction (L axis direction) may be longer than the length in the width direction (W axis direction).

[0114] Reference Figures 13 to 15 , the multilayer capacitor 100 according to the embodiment may include a capacitor body 110 and first and second external electrodes 131 and 132 disposed at both ends of the capacitor body 110 opposite to each other in a length direction (L-axis direction).

[0115] For example, the capacitor body 110 may have an approximately hexahedral shape.

[0116] In an embodiment, for ease of description, two surfaces of the capacitor body 110 opposite to each other in the thickness direction (T-axis direction) will be 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) will be defined as a third surface and a fourth surface, and two surfaces connected to the third surface and the fourth surface and opposite to each other in the width direction (W-axis direction) will be defined as a fifth surface and a sixth surface.

[0117] As an example, the first surface as the bottom surface may be a mounting surface. In addition, the first to sixth surfaces may be flat, but the embodiment is not limited thereto, for example, the first to sixth surfaces may be curved surfaces whose central portions are convex, and the edges of the respective surfaces may be rounded.

[0118] 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 drawings of the embodiment.

[0119] The capacitor body 110 can be obtained by stacking a plurality of dielectric layers 111 in a thickness direction (T-axis direction) and sintering the dielectric layers 111, and the capacitor body 110 may include a plurality of dielectric layers 111 and a first internal electrode 121 and a second internal electrode 122, the first internal electrode 121 and the second internal electrode 122 being alternately arranged in the thickness direction (T-axis direction), and the dielectric layer 111 being between the first internal electrode 121 and the second internal electrode 122.

[0120] In this case, the respective dielectric layers 111 adjacent to each other in the capacitor body 110 may be integrated so that it is difficult to distinguish a boundary therebetween without using a scanning electron microscope (SEM).

[0121] Furthermore, capacitor body 110 may include an active area and footprints 112 and 113 .

[0122] The effective region is a portion contributing to forming the capacitance of the multilayer capacitor 100. As an example, the effective region may be a region where the first internal electrodes 121 or the second internal electrodes 122 stacked in the thickness direction (T-axis direction) overlap each other.

[0123] Covering areas 112 and 113 as thickness-direction edge portions may be located on the top and bottom surfaces of the active area in the thickness direction (T-axis direction), respectively. In the covering areas 112 and 113, a single dielectric layer or two or more dielectric layers may be stacked on the top and bottom surfaces of the active area, respectively.

[0124] In addition, the capacitor body 110 may include a side cover region. The side cover regions as the widthwise edge portions may be located on both side surfaces of the effective region in the widthwise direction (W-axis direction), respectively. The side cover regions may be formed by applying the conductive paste layer for forming the internal electrode to the surface of the dielectric green sheet only to a portion of the surface of the dielectric green sheet, or by stacking dielectric green sheets not coated with the conductive paste layer on both sides of the dielectric green sheet stack and sintering the dielectric green sheet stack.

[0125] The cover regions 112 and 113 and the side cover regions serve to prevent the first and second internal electrodes 121 and 122 from being damaged due to physical stress or chemical stress.

[0126] The dielectric layer 111 includes the dielectric composition according to the above-described embodiment. Therefore, the dielectric layer 111 having improved compactness (reduced porosity) is included to realize the multilayer capacitor 100 having enhanced dielectric characteristics and moisture-proof reliability. The dielectric composition has been described in detail in the above-described embodiment, so the description thereof is omitted here.

[0127] As an example, the average thickness of the dielectric layer 111 may be greater than or equal to 0.05 μm and less than or equal to 0.1 μm, or may be 0.5 μm or greater, and may be 10 μm or less, 5 μm or less, or 2.5 μm or less.

[0128] The average thickness of the dielectric layer 111 may be: in the SEM image of the cross-sectional sample, the center point of the length direction (L-axis direction) or the width direction (W-axis direction) of the dielectric layer 111 is set as a reference point, and the arithmetic mean value of the thickness of the dielectric layer 111 at 10 points spaced apart from the reference point by a predetermined interval. The intervals of the 10 points may be controlled according to the scale of the SEM image, for example, the intervals of the 10 points may be 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm. In this case, all of the 10 points should be located in the dielectric layer 111, and when all of the 10 points are not located in the dielectric layer 111, the position of the reference point may be changed or the intervals between the 10 points may be controlled.

[0129] The first internal electrode 121 and the second internal electrode 122, which are electrodes having different polarities, are alternately arranged opposite to each other in the T-axis direction, and the dielectric layer 111 is interposed between the first internal electrode 121 and the second internal electrode 122, and one end of the first internal electrode 121 and one end of the second internal electrode 122 can be alternately exposed through the third surface and the fourth surface of the capacitor body 110.

[0130] The first and second internal electrodes 121 and 122 may be electrically insulated from each other by a dielectric layer 111 disposed between the first and second internal electrodes 121 and 122 .

[0131] Ends of the first and second internal electrodes 121 and 122 alternately exposed through the third and fourth surfaces of the capacitor body 110 may be connected and electrically connected to the first and second external electrodes 131 and 132 , respectively.

[0132] The first and second internal electrodes 121 and 122 may include a conductive metal, for example, may include a metal such as Ni, Cu, Ag, Pd, or Au, or an alloy thereof, for example, an Ag—Pd alloy.

[0133] In addition, the first and second internal electrodes 121 and 122 may also include dielectric particles having the same composition as the ceramic material included in the dielectric layer 111 .

[0134] The first and second internal electrodes 121 and 122 may be formed by using a conductive paste including a conductive metal, and a printing method of the conductive paste may employ a screen printing method or a gravure printing method.

[0135] As an example, the average thickness of the first and second internal electrodes 121 and 122 may be 0.05 μm or more, 0.1 μm or more, 0.2 μm or more, or 0.25 μm or more, and may be 2.5 μm or less, 1 μm or less, or 0.5 μm or less.

[0136] The average thickness of the first internal electrode 121 or the second internal electrode 122 may be: in the SEM image of the cross-sectional sample, the center point in the length direction (L-axis direction) or the width direction (W-axis direction) of the first internal electrode 121 or the second internal electrode 122 is set as a reference point, and the arithmetic mean value of the thickness of the first internal electrode 121 or the second internal electrode 122 at 10 points spaced apart from the reference point by a predetermined interval. The interval of the 10 points may be controlled according to the scale of the SEM image, for example, the interval of the 10 points may be an interval of 1 μm to 100 μm, 1 μm to 50 μm, or 1 μm to 10 μm. In this case, all of the 10 points should be located in the first internal electrode 121 or the second internal electrode 122, and when all of the 10 points are not located in the first internal electrode 121 or the second internal electrode 122, the position of the reference point may be changed or the interval between the 10 points may be controlled.

[0137] The first and second external electrodes 131 and 132 may be supplied with voltages having different polarities and may be connected and electrically connected to exposed portions of the first and second internal electrodes 121 and 122 , respectively.

[0138] According to this configuration, when a predetermined voltage is applied to the first external electrode 131 and the second external electrode 132, charges are accumulated between the first internal electrode 121 and the second internal electrode 122 facing each other. In this case, the capacitance of the multilayer capacitor 100 is proportional to the overlapping area of ​​the first internal electrode 121 and the second internal electrode 122 overlapping each other in the T-axis direction in the active region.

[0139] The first outer electrode 131 may include a first connection portion arranged on the third surface of the capacitor body 110 and connected to the first inner electrode 121, and a first band portion arranged at a corner where the third surface of the capacitor body 110 intersects with the first surface and the second surface or the fifth surface and the sixth surface, and the second outer electrode 132 may include a second connection portion arranged on the fourth surface of the capacitor body 110 and connected to the second inner electrode 122, and a second band portion arranged at a corner where the fourth surface of the capacitor body 110 intersects with the first surface and the second surface or the fifth surface and the sixth surface.

[0140] The first band portion may extend from the first connection portion to a portion of the first surface and a portion of the second surface or a portion of the fifth surface and a portion of the sixth surface of the capacitor body 110, and the second band portion may extend from the second connection portion to a portion of the first surface and a portion of the second surface or a portion of the fifth surface and a portion of the sixth surface of the capacitor body 110. The first band portion may be used to enhance the fixing strength of the first external electrode 131, and the second band portion may be used to enhance the fixing strength of the second external electrode 132.

[0141] As an example, each of the first and second external electrodes 131 and 132 may include a sintered metal layer contacting the capacitor body 110 and a plating layer disposed to cover the sintered metal layer.

[0142] The sintered metal layer may include conductive metal and glass.

[0143] As an example, the sintered metal layer may include copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb), their alloys or combinations thereof as the conductive metal, for example, the conductive metal including copper (Cu) may mean that the conductive metal includes copper (Cu) alone or a copper (Cu) alloy. When the conductive metal includes copper, the amount of metal other than copper may be less than or equal to 5 mol parts relative to 100 mol parts of copper.

[0144] As an example, the sintered metal layer may include a composition in which an oxide is mixed as glass, for example, at least one 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 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 at least one selected from the group consisting of lithium (Li), sodium (Na), and potassium (K), and the alkaline earth metal may be at least one selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0145] Alternatively, the conductive resin layer may be formed on the sintered metal layer, for example, the conductive resin layer may be formed in a form that completely covers the sintered metal layer. In addition, the first external electrode 131 and the second external electrode 132 may not include the sintered metal layer, and in this case, the conductive resin layer may be in direct contact with the capacitor body 110.

[0146] The conductive resin layer may extend to the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110, and the length of the region (i.e., the band portion) where the conductive resin layer extends and is disposed on the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110 may be longer than the length of the region (i.e., the band portion) where the sintered metal layer extends and is disposed on the first and second surfaces or the fifth and sixth surfaces of the capacitor body 110. That is, the conductive resin layer may be formed on the sintered metal layer, for example, in a form that completely covers the sintered metal layer.

[0147] The conductive resin layer includes resin and conductive metal.

[0148] The resin included in the conductive resin layer may be a resin having adhesiveness and shock absorption properties and is not particularly limited, for example, the resin included in the conductive resin layer may include phenolic resin, acrylic resin, silicone resin, epoxy resin, or polyimide resin.

[0149] The conductive metal included in the conductive resin layer serves to be electrically connected with the first and second internal electrodes 121 and 122 and / or the sintered metal layer.

[0150] The conductive metal included in the conductive resin layer may have a spherical shape, a flake shape, or a combination thereof. That is, the conductive metal may be formed only in a flake shape, may be formed only in a spherical shape, or may be a mixture of a flake shape and a spherical shape.

[0151] Here, spherical may also include forms other than completely spherical, for example, may include a form in which the length ratio of the major axis to the minor axis (major axis / minor axis) is 1.45 or less. Flaky powder may refer to a powder having a flat or elongated form, and is not particularly limited, but for example, the length ratio of the major axis / minor axis (major axis / minor axis) may be 1.95 or more.

[0152] The first and second external electrodes 131 and 132 may further include a plating layer disposed outside the conductive resin layer.

[0153] The plating layer may include a single nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti) or lead (Pb) or an alloy thereof. As an example, the plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or may be a nickel (Ni) plating layer or a tin (Sn) plating layer stacked in sequence, or may be a tin (Sn) plating layer, a nickel (Ni) plating layer and a tin (Sn) plating layer stacked in sequence. In addition, the plating layer may also include a plurality of nickel (Ni) plating layers and / or a plurality of tin (Sn) plating layers.

[0154] The plating layer may improve the mountability on a substrate, structural reliability, durability to the outside, heat resistance, and equivalent series resistance (ESR) of the multilayer capacitor 100 .

[0155] Method for manufacturing multilayer capacitor

[0156] A method of manufacturing a multilayer capacitor according to another embodiment includes the steps of manufacturing a dielectric powder including gallium (Ga), manufacturing a capacitor body including a dielectric layer and an inner electrode, and forming an outer electrode outside the capacitor body.

[0157] First, a method of producing a dielectric powder containing Ga is described.

[0158] As an example, Ga is added to a precursor of a barium titanate-based dielectric to prepare a dielectric mixture. Ga can be added in the form of microparticles having an average particle size of 1 nm to 15 nm, and can be added in the form of a complex with a phase stabilizer, a surfactant, or a dispersant. For example, the average particle size of the Ga particles can be determined by a particle size analyzer. Even if not described in the present disclosure, other methods and / or tools known to those of ordinary skill in the art can also be used.

[0159] The dielectric mixture is uniformly mixed and dried, and then heat-treated to obtain a dielectric powder, thereby preparing a dielectric powder containing Ga.

[0160] When the manufactured dielectric powder containing Ga is included in a dielectric paste and sintered at a temperature of 1000° C. to 1200° C., Ga having a low melting point may form a first second phase together with Al, Si or Mg. Since the first second phase is used to reduce the sintering temperature, the first second phase improves the compactness of the dielectric (reduces the porosity of the dielectric) to enhance the dielectric characteristics and reliability of the capacitor.

[0161] Next, a method of manufacturing the capacitor body is described.

[0162] In the manufacturing process of the capacitor body, a conductive paste and a dielectric paste are prepared. The conductive paste becomes an internal electrode after sintering, and the dielectric paste becomes a dielectric layer after sintering.

[0163] For example, the dielectric paste is manufactured by the following method. The manufactured dielectric powder containing Ga is uniformly mixed by a method such as wet mixing, and dried, and then heat-treated under predetermined conditions to obtain the dielectric powder. An organic vehicle or an aqueous vehicle is added to the obtained dielectric powder and kneaded to prepare the dielectric paste.

[0164] The obtained dielectric paste is made into a sheet by a technique such as a doctor blade method to obtain a dielectric green sheet. In addition, the dielectric paste may contain an additive selected from various dispersants, plasticizers, dielectrics, subcomponent compounds or glass as needed.

[0165] The conductive paste for the internal electrode is prepared by mixing a conductive powder made of a conductive metal or an alloy thereof and a binder or a solvent. The conductive paste for the internal electrode may contain a ceramic powder (e.g., barium titanate powder) as an inhibitor as needed. The inhibitor may be used to inhibit the sintering of the conductive powder during the sintering process.

[0166] The conductive paste for the internal electrode is applied to the surface of the dielectric green sheet in a predetermined pattern by various printing methods including screen printing or a transfer method. In addition, a plurality of dielectric green sheets formed with the internal electrode pattern are stacked, and then pressed in a stacking direction to obtain a dielectric green sheet stack. In this case, the dielectric green sheets and the internal electrode pattern may be stacked so that the dielectric green sheets not formed with the internal electrode pattern are located at the upper and lower parts of the dielectric green sheet stack in the stacking direction to form a cover area.

[0167] Alternatively, the obtained dielectric green sheet laminate may be cut into a predetermined size by dicing or the like.

[0168] In addition, the dielectric green sheet stack may be cured and dried as needed to remove the plasticizer, and after the curing and drying, drum polishing may be performed by using a horizontal centrifugal drum machine. In drum polishing, the dielectric green sheet stack is placed in a drum container together with a medium and a polishing liquid, and a rotational motion or vibration is applied to the drum container to polish unnecessary parts (such as burrs generated during cutting). In addition, after drum polishing, the dielectric green sheet stack may be cleaned with a cleaning liquid such as water and dried.

[0169] The dielectric green sheet laminate is subjected to a binder removal process and a sintering process to obtain a capacitor body.

[0170] The conditions of the debinding process may be appropriately controlled according to the main component composition of the dielectric layer or the main component composition of the inner electrode. For example, the heating rate during the debinding process may be 5° C. / hour to 300° C. / hour, the treatment temperature may be 180° C. to 400° C., and the temperature may be maintained for 0.5 hour to 24 hours. The debinding atmosphere may be air or a reducing atmosphere.

[0171] The conditions of the sintering process may be appropriately controlled according to the main component composition of the dielectric layer or the main component composition of the internal electrode.

[0172] Regarding the dielectric composition according to the embodiment, the first second phase is used to reduce the sintering temperature when sintering the dielectric composition, and as an example, the sintering temperature may be 1000°C to 1200°C, for example, 1050°C to 1200°C, or 1050°C to 1150°C.

[0173] Therefore, by setting the sintering temperature to a relatively low temperature, the compactness is improved (the porosity is reduced), thereby realizing a capacitor with high reliability.

[0174] As an example, the sintering time may be 0.5 hours to 8 hours, or 1 hour to 3 hours. The sintering atmosphere may be a reducing atmosphere, for example, an atmosphere in which a mixed gas of nitrogen (N2) and hydrogen (H2) is moistened. When the inner electrode includes nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the sintering atmosphere may be 1.0×10 -14 MPa to 1.0×10 -10 MPa.

[0175] After the sintering process, annealing may be performed as needed. Annealing is a process for reoxidizing the dielectric layer, and annealing may be performed when the sintering process is performed under a reducing atmosphere. The conditions of the annealing process may also be appropriately controlled according to the main component composition of the dielectric layer. For example, the annealing temperature may be 950°C to 1150°C, the annealing time may be 0 hours to 20 hours, and the heating rate may be 50°C / hour to 500°C / hour. The annealing atmosphere may be a humidified nitrogen (N2) atmosphere, and the oxygen partial pressure may be 1.0×10 -9 MPa to 1.0×10 -5 MPa.

[0176] In the binder removal process, sintering process or annealing process, for example, water may be used to wet the nitrogen gas or the mixed gas, and in this case, the water temperature may be 5° C. to 75° C. The binder removal process, sintering process and annealing process may be performed continuously or independently.

[0177] Optionally, the third surface and the fourth surface of the obtained capacitor body may be subjected to surface treatment such as sandblasting, laser irradiation or barrel polishing. By performing the surface treatment, the end of the first inner electrode and the end of the second inner electrode may be exposed to the outermost surface, and as a result, 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 excellent, and the alloy portion may be easily formed.

[0178] A sintered metal layer forming paste for forming a sintered metal layer of an external electrode is applied on the outer surface of the obtained capacitor body and then sintered to form a sintered metal layer.

[0179] The sintered metal layer forms paste and can comprise conductive metal and glass.The description of conductive metal and glass is identical with the above description, so repeated description is omitted.In addition, the sintered metal layer forms paste and can optionally comprise the secondary component such as adhesive, solvent, dispersant, plasticizer or oxide powder.For example, adhesive can adopt ethyl cellulose, acrylic acid or butyral, and solvent can adopt organic solvent or aqueous solvent such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone or toluene.

[0180] The method for applying the sintered metal layer forming paste onto the outer surface of the capacitor body may adopt a dipping method, various printing methods such as screen printing, a coating method using a dispenser or the like, or a spraying method using a sprayer. The sintered metal layer forming paste may be applied at least on the third and fourth surfaces of the capacitor body, and may also be optionally applied on portions of the first, second, fifth, or sixth surfaces where the band portions of the first and second external electrodes are formed.

[0181] Then, the capacitor body coated with the sintered metal layer forming paste is dried and sintered at a temperature of 700° C. to 1000° C. for 0.1 hour to 3 hours to form a sintered metal layer.

[0182] Alternatively, a conductive resin layer forming paste is applied to the outer surface of the obtained capacitor body and cured to form a conductive resin layer.

[0183] Conductive resin layer forms paste and can comprise resin, and optionally comprises conductive metal or non-conductive filler.The description of conductive metal and resin is identical with the above description, therefore omits repeated description.In addition, conductive resin layer forms paste and can optionally comprise the secondary component such as adhesive, solvent, dispersant, plasticizer or oxide powder.For example, adhesive can adopt ethyl cellulose, acrylic acid or butyral, and solvent can adopt organic solvent or aqueous solvent such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone or toluene.

[0184] As an example, in the method for forming a conductive resin layer, the capacitor body 110 is immersed in a conductive resin layer forming paste and cured, or the conductive resin layer forming paste is printed onto the surface of the capacitor body 110 by screen printing or gravure printing, or the conductive resin layer forming paste is applied to the surface of the capacitor body 110 and cured, thereby forming a conductive resin layer.

[0185] Next, a plating layer is formed on the outside of the conductive resin layer.

[0186] As an example, the plated layer may be formed by a plating method, and may also be formed by sputtering or electrodeposition.

[0187] Hereinafter, specific examples of the present disclosure are provided. However, the examples disclosed below are only used to illustrate or describe the present disclosure in detail, and therefore should not limit the scope of the present disclosure.

[0188] Example

[0189] (Preparation Example: Preparation of Dielectric Composition)

[0190] Preparation Example 1

[0191] First, a mixture mixed with Ga (particle size: 5 nm), a surfactant, and a phase stabilizer was dispersed in an ethanol solvent. BaTiO3 was added to the dispersed mixture, and a dielectric mixture was prepared to include 0.9 mol of Ga (particle size: 5 nm) based on 100 mol parts of BaTiO3. The dielectric mixture was uniformly mixed and dried, and then heat-treated to obtain a dielectric powder, thereby manufacturing a dielectric powder containing gallium (Ga) according to Preparation Example 1.

[0192] Comparative Preparation Example 1

[0193] A dielectric powder not containing gallium (Ga) according to Comparative Preparation Example 1 was prepared in the same manner as the above Preparation Example 1 except that Ga was not added.

[0194] Comparative Preparation Example 2

[0195] A dielectric powder including gallium (Ga) according to Comparative Preparation Example 2 was prepared in the same manner as the above Preparation Example 1 except that oxide-type Ga having a particle size of 500 nm was added.

[0196] (Example: Manufacturing of multilayer capacitors)

[0197] Ethanol, toluene, a dispersant, and a binder were mixed with the dielectric powder containing gallium (Ga) prepared in Preparation Example 1 and Comparative Preparation Examples 1 and 2, and then mechanically ground to prepare a dielectric slurry.

[0198] A dielectric green sheet was prepared using the prepared dielectric slurry by using a head jet type roll coater.

[0199] A conductive paste layer containing nickel (Ni) was printed on the surface of the dielectric green sheet, and the dielectric green sheets with the conductive paste layer were stacked and compressed to prepare a dielectric green sheet stack (length×width×height=3.2 mm×2.5 mm×2.5 mm).

[0200] The dielectric green sheet stack is plastically processed in a nitrogen atmosphere at 400°C or lower and fired at a sintering temperature of 1100°C and a hydrogen concentration of 1.0% H2 or lower to prepare a capacitor body, and then external electrodes are formed on the outside of the capacitor body to prepare the multilayer capacitors in Example 1 and Comparative Examples 1 and 2.

[0201] Evaluation example

[0202] Evaluation Example 1: Analysis of the Content of Constituent Elements of the Second Phase Including Ga

[0203] The multilayer capacitor 1 in Example 1 and Comparative Example 2 is placed in an epoxy mixture and cured, and then the L-axis and T-axis sides of the capacitor body are polished to 1 / 2 in the W-axis direction, and fixed and maintained in a vacuum atmosphere to prepare a cross-sectional sample cut along the L-axis and T-axis directions at the center of the capacitor body 110 in the W-axis direction.

[0204] Then, any dielectric layer located in the active area or the cover area of ​​the cross-sectional sample is selected, and then a transmission electron microscope (TEM) image is obtained in an area of ​​5 μm×5 μm. For reference, the second phase may correspond to a relatively dark area in the TEM image.

[0205] A mapping image of Ga is obtained from the TEM image, and then any first and second phases containing Ga are selected by using TEM-EDS to obtain contents (moles) of Si, Al, and Mg based on 1 mole of Ga.

[0206] Figure 5 : is a graph analyzing the content of the second phase constituent component of the dielectric composition included in the multilayer capacitors in Example 1 and Comparative Example 2.

[0207] Reference Figure 5 , it can be seen that, in the case of Example 1, the second phase containing Ga contains 1.95 mol of Si, 1.43 mol of Al, and 0.59 mol of Mg based on 1 mol of Ga.

[0208] In contrast, it can be seen that in the case of Comparative Example 2, very small amounts of Si, Al, and Mg are contained compared to Ga, so the second phase containing Ga is not combined with other elements, and Ga exists alone.

[0209] Evaluation Example 2: Evaluation of sintered density and compactness

[0210] Figure 6 is a graph showing the sintered density of the dielectric compositions prepared in Preparation Example 1 and Comparative Preparation Examples 1 and 2 for each sintering temperature.

[0211] Specifically, the dielectric compositions prepared in Preparation Example 1 and Comparative Examples 1 and 2 were prepared into cubic (K2 block) samples, and then the pellets were sintered at a temperature of 1050° C. to 1150° C. for 90 minutes to measure the density (g / cm 3 ). In this case, when the density reaches 5.7 g / cm 3 Up to 5.8g / cm 3When the sintering is completed, the density is ensured (the porosity is reduced).

[0212] Reference Figure 6 It can be seen that in the case of Preparation Example 1, the sintering density reaches 5.7 g / cm before 1100 °C. 3 Up to 5.8g / cm 3 , and it can be seen that in the case of Comparative Examples 1 and 2, the sintered density reaches 5.7 g / cm at about 1125 °C. 3 Up to 5.8g / cm 3 Therefore, it can be seen that the sintering of the dielectric composition in Preparation Example 1 is completed at a relatively low temperature.

[0213] FIG. 7A to FIG. 7L SEM images are shown, which show the density level according to the sintering temperature of the dielectric composition included in the multilayer capacitor in Example 1 and Comparative Examples 1 and 2. The SEM image may be an image in which any dielectric layer located in the active area or the cover area of ​​a cross-sectional sample of the multilayer capacitor is selected and a transmission electron microscope (TEM) image is obtained in an area of ​​5 μm×5 μm.

[0214] Reference FIG. 7A to FIG. 7L It can be seen that in the case of Example 1, the density is ensured (the porosity is reduced) at 1100°C, while in the case of Comparative Example 1, the density is ensured (the porosity is reduced) at 1150°C, and in the case of Comparative Example 2, the density is ensured (the porosity is reduced) at 1125°C.

[0215] Fig. 8A A SEM image of a cross-sectional sample of the multilayer capacitor in Comparative Example 1 is shown. Figure 8B A SEM image of a cross-sectional sample of the multilayer capacitor in Example 1 is shown.

[0216] Reference Fig. 8A and Figure 8B It can be seen that the density in the multilayer capacitor in Example 1 is significantly higher than that in Comparative Example 1.

[0217] Evaluation Example 3: Evaluation of Dielectric Constant (ε)

[0218] For the multilayer capacitors prepared in Example 1 and Comparative Examples 1 and 2, the dielectric constant ε was measured under the conditions of 1 kHz and 1 V by using a 4268A capacitance meter (manufactured by Agilent) product as an LCR meter device. The dielectric constant according to the temperature change of 1050° C. to 1150° C. was measured, and the measurement results are shown in Fig. 9 In the diagram shown.

[0219] Reference Fig. 9, it can be seen that, based on the sintering temperature of 1100° C., the dielectric constant of the capacitor in Example 1 is sufficiently high, while the dielectric constants of the capacitors in Comparative Examples 1 and 2 are relatively very low.

[0220] Evaluation Example 4: Evaluation of moisture resistance reliability

[0221] 100 multilayer capacitor samples were prepared in each of Example 1 and Comparative Examples 1 and 2, and then the samples were mounted on a measurement substrate, and the moisture resistance reliability of the samples was measured by using an ESPEC (PR-3J, 8585) apparatus at 95° C., 85% relative humidity (RH), 13 V, and 12 hours, and the measurement results are shown in Figures 10 to 12 In the diagram shown.

[0222] pass Figures 10 to 12 , it can be seen whether the insulation resistance (IR) of the multilayer capacitor is maintained stably over time.

[0223] Reference Figures 10 to 12 , in the case of Comparative Examples 1 and 2, it can be seen that the insulation resistance (IR) decreases and thus the samples are inferior, whereas in Example 1, it can be seen that the IR remains stable. As a result, it can be seen that the moisture resistance reliability of the multilayer capacitor in Example 1 is significantly improved compared to the multilayer capacitors in Comparative Examples 1 and 2.

[0224] While the present disclosure has been described in conjunction 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 is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A dielectric composition comprising: Dielectric grains including a barium titanate-based compound; as well as The second phase, located between the dielectric grains, The second phase includes a first second phase including Ga and Si.

2. The dielectric composition according to claim 1, wherein: The dielectric grains including the barium titanate-based compound are a main phase, The average area of ​​the major phase is 85% or more of the total area of ​​the dielectric composition, and The average area of ​​the second phase is 15% or less of the total area of ​​the dielectric composition.

3. The dielectric composition according to claim 1, wherein: The first second phase further includes Al and / or Mg.

4. The dielectric composition according to claim 3, wherein: Relative to 1 mole of Ga, the first second phase includes: Si in an amount of 1.0 to 3.0 parts by mole, Al in an amount of 0.5 to 2.5 parts by mole, and Mg in an amount of 0.2 to 1.2 parts by mole.

5. The dielectric composition according to claim 1, wherein: The average area occupied by the first second phase is 50% to 95% relative to the total area of ​​the second phase.

6. The dielectric composition according to claim 5, wherein: The second phase further includes a second second phase, the second second phase includes Si and does not contain Ga, and The average area occupied by the second phase is 5% to 50% relative to the total area of ​​the second phase.

7. The dielectric composition according to claim 6, wherein: A ratio of an average area occupied by the first second phase relative to a total area of ​​the second phase to an average area occupied by the second second phase relative to a total area of ​​the second phase is 1.5 to 2.

5. 8 . The dielectric composition of claim 1 , comprising Ga in an amount of 0.1 wt % to 0.5 wt % based on the total weight of all ingredients of the dielectric composition.

9. A multilayer capacitor comprising: a capacitor body including a dielectric layer and inner electrodes; as well as An external electrode, disposed outside the capacitor body, The dielectric layer includes dielectric grains and a second phase located between the dielectric grains, the dielectric grains include a barium titanate-based compound, and The second phase includes a first second phase including Ga and Si.

10. The multilayer capacitor of claim 9, wherein: The dielectric grains including the barium titanate-based compound are the main phase, The average area of ​​the main phase is 85% or more of the total area of ​​the dielectric layer, and The average area of ​​the second phase is 15% or less of the total area of ​​the dielectric layer.

11. The multilayer capacitor of claim 9, wherein: The first second phase further includes Al and / or Mg.

12. The multilayer capacitor of claim 11, wherein: Relative to 1 mole of Ga, the first second phase includes: Si in an amount of 1.0 to 3.0 parts by mole, Al in an amount of 0.5 to 2.5 parts by mole, and Mg in an amount of 0.2 to 1.2 parts by mole.

13. The multilayer capacitor of claim 9, wherein: The average area occupied by the first second phase is 50% to 95% relative to the total area of ​​the second phase.

14. The multilayer capacitor of claim 13, wherein: The second phase further includes a second second phase, the second second phase includes Si and does not contain Ga, and The average area occupied by the second phase is 5% to 50% relative to the total area of ​​the second phase.

15. The multilayer capacitor of claim 14, wherein: A ratio of an average area occupied by the first second phase relative to a total area of ​​the second phase to an average area occupied by the second second phase relative to a total area of ​​the second phase is 1.5 to 2.

5.

16. The multilayer capacitor according to claim 9, wherein The dielectric layer includes Ga in an amount of 0.1 wt % to 0.5 wt % based on the total weight of all components of the dielectric layer.

17. A method for manufacturing a multilayer capacitor, comprising: Manufacturing a dielectric powder comprising Ga, wherein manufacturing the dielectric powder comprising Ga comprises adding Ga having an average particle size of 1 nm to 15 nm to a precursor of a barium titanate-based dielectric; manufacturing a dielectric green sheet by using the dielectric powder, and forming a conductive paste layer on a surface of the dielectric green sheet; manufacturing a dielectric green sheet laminate by laminating a plurality of the dielectric green sheets, wherein the conductive paste layer is formed on each of the plurality of dielectric green sheets; manufacturing a capacitor body including a dielectric layer and an internal electrode by sintering the dielectric green sheet laminate; and External electrodes are formed on an outer surface of the capacitor body.

18. The method for manufacturing a multilayer capacitor according to claim 17, wherein: The sintering temperature for sintering the dielectric green sheet stack is 1000°C to 1200°C.

19. A dielectric composition comprising: Dielectric grains including a barium titanate-based compound; as well as The second phase is located between the dielectric grains, the second phase includes a first second phase and a second second phase, the first second phase includes Ga and Si, and the second second phase includes Si and does not contain Ga.

20. The dielectric composition according to claim 19, wherein The dielectric composition does not contain rare earth elements.

21. The dielectric composition of claim 20, wherein: The first second phase further includes Al and / or Mg.

22. The dielectric composition of claim 21, wherein: Relative to 1 mole of Ga, the first second phase includes: Si in an amount of 1.0 to 3.0 parts by mole, Al in an amount of 0.5 to 2.5 parts by mole, and Mg in an amount of 0.2 to 1.2 parts by mole. 23 . The dielectric composition of claim 22 , comprising Ga in an amount of 0.1 wt % to 0.5 wt % based on the total weight of all ingredients of the dielectric composition.

24. A multilayer capacitor comprising: a capacitor body including a dielectric layer and inner electrodes; as well as An external electrode, disposed outside the capacitor body, The dielectric layer includes dielectric grains and a second phase located between the dielectric grains, the dielectric grains include a barium titanate-based compound, and The second phase includes a first second phase and a second second phase, the first second phase includes Ga and Si, and the second second phase includes Si and does not contain Ga.

25. The multilayer capacitor of claim 24, wherein: The dielectric layer does not contain rare earth elements, The dielectric grains including the barium titanate-based compound are a main phase, The average area of ​​the main phase is 85% or more of the total area of ​​the dielectric layer, and The average area of ​​the second phase is 15% or less of the total area of ​​the dielectric layer.

26. The multilayer capacitor of claim 25, wherein: The first second phase further includes Al and / or Mg.

27. The multilayer capacitor of claim 26, wherein: Relative to 1 mole of Ga, the first second phase includes: Si in an amount of 1.0 to 3.0 parts by mole, Al in an amount of 0.5 to 2.5 parts by mole, and Mg in an amount of 0.2 to 1.2 parts by mole.

28. The multilayer capacitor of claim 27, wherein: The dielectric layer includes Ga in an amount of 0.1 wt % to 0.5 wt % based on the total weight of all components of the dielectric layer, The average area occupied by the first second phase is 50% to 95% relative to the total area of ​​the second phase, and The average area occupied by the second phase is 5% to 50% relative to the total area of ​​the second phase.

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