Patent Publication Number: US-2023140133-A1

Title: Tantalum capacitor

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     The present application claims the benefit of priority to Korean Patent Application No. 10-2021-0145574, filed on Oct. 28, 2021 in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a tantalum capacitor, and more particularly, to a tantalum capacitor having improved reliability by reducing a moisture absorption amount without increasing equivalent series resistance. 
     BACKGROUND 
     Tantalum (Ta) is a metal that is widely used throughout various industries such as the electrical, electronic, mechanical, chemical, aerospace, and military industries, due to having mechanical and physical characteristics such as a high melting point, excellent ductility and excellent corrosion-resistance, or the like. 
     In particular, since the tantalum material may form the most stable anodic oxide film, tantalum has been widely used as a material in forming anodes for small capacitors. 
     Moreover, due to the rapid development of the IT industry, such as electronics and information and communication, the use of tantalum is increasing rapidly every year. 
     A tantalum capacitor has a structure that uses a gap that appears when the tantalum powder is sintered and hardened, and forms tantalum oxide (Ta 2 O 5 ) on a surface of the tantalum as an electrode metal by an anodic oxidation method, and uses the oxide as a dielectric to form a manganese dioxide (MnO 2 ) layer or a conductive polymer layer thereon as a solid electrolyte. 
     In addition, due to the derivation of a cathode electrode, a silver (Ag) layer is formed as a carbon layer and a metal layer on the manganese dioxide (MnO 2 ) layer or the conductive polymer layer. 
     A tantalum capacitor has characteristics such as low equivalent series resistance (ESR) and high ripple current rating. 
     For this reason, the tantalum capacitor may have significantly improved temperature dependence and a longer service life than an aluminum electrolyte capacitor. 
     However, high moisture absorption properties of a conductive polymer layer may affect reliability evaluation and may cause a need for an additional solution improve performance of the polymer itself. In particular, a non-conductive material may be contained in the conductive polymer layer to effectively block a current path through which leakage current (LC) is generated. 
     SUMMARY 
     An aspect of the present disclosure is to provide a tantalum capacitor having improved reliability by reducing a moisture absorption rate without increasing equivalent series resistance. 
     Another aspect of the present disclosure is to provide a tantalum capacitor having reliability improved in a high-temperature or high-humidity environment. 
     According to an aspect of the present disclosure, a tantalum capacitor includes: a tantalum body including a sintered tantalum body including tantalum particle, a conductive polymer layer disposed on the sintered tantalum body and including a first filler, and a tantalum wire penetrating through at least a portion of each of the sintered tantalum body and the conductive polymer layer in a first direction. A ratio of an area of the first filler to an area of the conductive polymer layer is greater than 0.38 in a first cross-section partially overlapping the sintered tantalum body, among cross-sections perpendicular to the first direction. 
     According to an aspect of the present disclosure, a tantalum capacitor includes: a sintered tantalum body including tantalum particle; a conductive polymer layer disposed on the sintered tantalum body and comprising a first filler; a carbon layer disposed on the conductive polymer layer; and a tantalum body comprising a tantalum wire penetrating through at least a portion of each of the sintered tantalum body and the conductive polymer layer in a first direction. When a cross-section partially overlapping the sintered tantalum body, among cross-sections perpendicular to the first direction, is a first cross-section including a plurality of first regions spaced apart from each other and each of the first region having a square shape of which a center of gravity is disposed on an extension line connecting a ⅓ point of a thickness of the conductive polymer layer, an average of ratios of an area of the first filler to an area of the conductive polymer layer in the plurality of first regions is greater than 0.38. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and other aspects, features, and advantages of the present disclosure will be more clearly understood from the following detailed description, taken in conjunction with the accompanying drawings. 
         FIG.  1    is a perspective view of a tantalum capacitor according to the present disclosure. 
         FIG.  2    is a cross-sectional view of a tantalum body in a tantalum capacitor according to the present disclosure, taken in an I-direction. 
         FIG.  3    is a cross-sectional view taken along line I-I′ of  FIG.  2   . 
         FIG.  4    is an enlarged view of region “A” of  FIG.  3   . 
         FIG.  5    is a cross-sectional view taken along line I-I′ of  FIG.  2    and illustrating a method of measuring a content of a filler in a conductive polymer layer according to the present disclosure. 
         FIG.  6    is an enlarged view of region “B” of  FIG.  5   . 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the present disclosure will be described as follows with reference to the attached drawings. It is not intended to limit the techniques described herein to specific embodiments, and it should be understood to include various modifications, equivalents, and/or alternatives to the embodiments of the present disclosure. In connection with the description of the drawings, similar reference numerals may be used for similar components. 
     In the drawings, for clarity of description, parts irrelevant to the description may be omitted, and thicknesses of elements may be magnified to clearly represent layers and regions. Components having the same functions within a scope of the same idea may be described using the same reference numerals. 
     Hereinafter, exemplary embodiments of the present disclosure will be described with reference to accompanying drawings. 
     In the drawings, an X-direction may be defined as a first direction, an L direction, or a length direction, a Y-direction may be defined as a second direction, a W direction, or a width direction, and a Z-direction defined as a third direction, a T direction, or a thickness direction. 
       FIG.  1    is a perspective view of a tantalum capacitor according to the present disclosure. 
     Referring to  FIG.  1   , the tantalum capacitor  1000  according to an exemplary embodiment may include a tantalum body  100  including tantalum powder (or particle), and having a tantalum wire  150  exposed to one end surface, a molding portion  200  having fifth and sixth surfaces  5  and  6  opposing each other in a first direction, third and fourth surfaces  3  and  4  opposing each other in a second direction, and first and second surfaces  1  and  2  opposing each other in a third direction, and formed to surround the tantalum body  100 , an anode lead frame  300  exposed to (or extend from) the second surface  2  of the molding portion  200  and electrically connected to the tantalum wire  150 , and a cathode lead frame  400  spaced apart from the anode lead frame  300  and exposed to (or extend from) the second surface  2  of the molding portion  200 . 
     The tantalum body  100  may have a tantalum wire  150  exposed in an X-direction of the body. In this case, the tantalum wire  150  may penetrate through at least a portion of the sintered tantalum body  110  in the first direction X. The tantalum wire  150  may be inserted into a mixture of the tantalum powder and a binder to be off-centered within the body, before mixed powder of the tantalum powder and the binder is compressed. For example, the tantalum body  100  may be manufactured by molding a tantalum element in a desired size by inserting the tantalum wire  150  into the tantalum powder mixed with the binder and sintering the tantalum element at a high temperature under high vacuum (10 −5  torr or less) for about 30 minutes. 
     The molding portion  200  may formed to cover the tantalum body  100  and to expose one surface of a first connection portion  320  of the anode lead frame  300  and one surface of a second connection portion  420  of the cathode lead frame  400 . 
     The molding portion  200  of the tantalum capacitor according to the present disclosure may be formed by transfer-molding a resin such as an epoxy molding compound (EMC) to surround the tantalum body  100 . The molding portion  200  may serve to protect the tantalum wire  150  and the tantalum body  100  from the outside. 
     The anode lead frame  300  may be formed of a conductive metal such as a nickel/iron alloy, and may include a first connection portion  320 , a first lead portion  330 , and a first bent portion  310 . The first bent portion  310  may be inclined toward the tantalum body  100  with respect to the first connection portion  320 . The first connection portion  320  of the anode lead frame  300  may be exposed to the second surface  2  of the molding portion  200 . The first connection portion  320  may be exposed to a lower surface of the molding portion  200  to serve as a terminal when a board is mounted. In this case, the third connection portion  320  may be spaced apart from the tantalum body  100  and may function as an anode of the tantalum capacitor  1000  according to the present disclosure. 
     The cathode lead frame  400  may be formed of a conductive metal such as a nickel/iron alloy, and may include a second bent portion, a second connection portion  420 , and a second lead portion  430  formed to be integrated with each other. 
     The second connection portion  420  may be disposed to be parallel to and spaced apart from the first connection portion  320  of the anode lead frame  300  in the first direction X. The second connection portion  420  of the cathode lead frame  400  may be exposed to the second surface  2  of the molding portion  200 . The second connection portion  420  may be exposed to a lower surface of the molding portion  200  to serve as a terminal when the board is mounted. In this case, the second connection portion  420  may be in contact with the tantalum body  100  and may function as a cathode of the tantalum capacitor  1000  according to the present disclosure. 
       FIG.  2    is a cross-sectional view of a tantalum body in a tantalum capacitor according to the present disclosure, taken in an I-direction. 
     Referring to  FIG.  2   , a tantalum body  100  of a tantalum capacitor  1000  according to an exemplary embodiment may include a sintered tantalum body  110  formed by sintering a molded body including a metal powder, a conductive polymer layer  120  disposed on the sintered tantalum body  110 , a carbon layer  130  disposed on the conductive polymer layer  120 , and a silver (Ag) layer  140  disposed on the carbon layer  130 . 
     The tantalum capacitor may further include a tantalum wire  150  having an insertion region, disposed inside the sintered tantalum body  110 , and a non-insertion region disposed outside the sintered tantalum body  110 . 
     The sintered tantalum body  110  may be formed by sintering a formed body including a metal powder and a binder. 
     For example, the sintered tantalum body  110  may be manufactured by mixing and stirring a metal powder, a binder, and a solvent at a predetermined ratio, compressing the mixed powder into a rectangular parallelepiped form, and sintering the compressed powder under high temperature and high vibration. 
     The metal powder is not limited as long as it may be used in the sintered tantalum body  110  of the tantalum capacitor  1000  according to an exemplary embodiment, and may be tantalum (Ta) powder. However, the metal powder may include at least one selected from the group consisting of aluminum (Al), niobium (Nb), vanadium (V), titanium (Ti) and zirconium (Zr), but is not limited thereto. Accordingly, rather than a sintered tantalum body, an aluminum sintered body, a niobium sintered body, or the like, may be used. 
     The binder is not limited and may include, for example, a cellulose-based binder. 
     The cellulose-based binder may include at least one selected from the group consisting of nitrocellulose, methyl cellulose, ethyl cellulose, and hydroxy propyl cellulose. 
     In addition, the tantalum wire  150  may be inserted into and mounted thereon to be eccentric from the center before compressing the mixed powder. 
     According to an exemplary embodiment, a dielectric oxide layer may be formed on the sintered tantalum body  110  as an insulating layer. For example, the dielectric oxide layer may be formed by growing an oxide layer (Ta 2 O 5 ) on a surface of the sintered tantalum body  110  by a chemical formation process using an electrochemical reaction. In this case, the dielectric oxide layer may change the sintered tantalum body  110  into a dielectric material. In addition, a conductive polymer layer  120  having a polarity of a cathode may be applied to the dielectric oxide layer. In some embodiments, the conductive polymer layer  120  is disposed directly on the dielectric oxide layer. 
     The conductive polymer layer  120  is not limited and may include, for example, a conductive polymer. 
     For example, a conductive polymer may be formed by polymerization or electrolytic polymerization of 3,4-ethylenedioxythiophene (EDOT) or pyrrole monomer, and may then be formed as a cathode layer having a conductive polymer cathode formed on an external surface of the sintered tantalum body  110  formed as an insulating layer. 
     For example, the conductive polymer layer  120  may be formed using polymer slurry, and the polymer slurry may include at least one of polypyrrole, polyaniline, or 3,4-ethylenedioxythiophene (EDOT). In addition, the conductive polymer layer  120  may include poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). PEDOT:PSS may be prepared by oxidative polymerization of EDOT using polystyrene sulfonate (PSS) as a template for balancing charges. 
     The carbon layer  130  may be laminated on the conductive polymer layer  120 , and may laminated by dissolving carbon powder in an organic solvent, containing an epoxy-based resin, to impregnate the sintered tantalum body  110  in a solution, in which the carbon powder is dissolved, and drying the organic solvent at a predetermined temperature to be volatilized. 
     In addition, the carbon layer  130  may serve to prevent silver (Ag) ions to passing therethrough. 
     A silver (Ag) layer  140 , formed of a silver (Ag) paste, may be included on an upper surface of the carbon layer  130 . 
     The silver (Ag) layer  140  may be laminated on the outside of the carbon layer  130  to improve conductivity. 
     In addition, the silver (Ag) layer  140  may improve the conductivity for polarity of the cathode layer to facilitate an electrical connection for polarity transfer. 
       FIG.  3    is a cross-sectional view taken along line I-I′ of  FIG.  2   . 
       FIG.  4    is an enlarged view of region “A” of  FIG.  3   . 
     In the case of the tantalum capacitor  1000  according to an exemplary embodiment, in the above-described conductive polymer layer  120 , a polymer slurry for forming the conductive polymer layer  120  may further include first and second fillers  121  and  122 . 
     In the present disclosure, the first filler  121  may be a non-conductive particle. As an example, the first filler  121  may be silica (SiO 2 ). However, exemplary embodiments are not limited thereto, and the first filler  121  may include one or more metal oxides, among BaTiO 3 , Al 2 O 3 , and ZrO 2 . In a tantalum capacitor according to the related art, a conductive polymer layer has high-moisture absorption properties, resulting in low reliability of a capacitor. In the present disclosure, the first filler  121  including non-conductive particles such as silica may be disposed in the conductive polymer layer  120 , so that a moisture absorption rate of the conductive polymer layer  120  may be effectively reduced. 
     In addition, the conductive polymer layer  120  in the present disclosure may include the first filler  121 , a non-conductive filler, so that a flow of current causing leakage current (LC) may be prevented and strength of the conductive polymer layer  120  may be increased to improve overall characteristics of the capacitor  1000 . 
     A cross-section of the tantalum body  100 , perpendicular to the first direction X includes a cross-section partially overlapping the sintered tantalum body  110 . In the partially overlapping cross-section, a ratio of an area of the first filler  121  to an area of the conductive polymer layer  120  may be greater than 0.38 to less than 0.83, in detail, 0.55 or more to 0.81 or less. In some embodiments, the ratio may be 0.55 or more and less than 0.83. 
     As an example of the above ratio, cross-sections of  FIG.  3    and  FIG.  4    are illustrated. Referring to  FIG.  3    which is a cross-sectional view taken along line I-I′ of  FIG.  2   , a first cross-section  1000 A of the tantalum body  100  is illustrated. The first cross-section  1000 A is a cross-section of the tantalum body  100 , taken using a cross-section in which a length of the sintered tantalum body  110  in the first direction X is cut by 2:1. 
     However, the first cross-section  1000 A is an example of the cross-section partially overlapping the sintered tantalum body  110 , among the cross-sections of the tantalum body  100 , perpendicular to the first direction X. The characteristics regarding the numerical range are not limited to the first cross-section  1000 A, and may be applied to other cross-sections perpendicular to the first direction X and overlapping the sintered tantalum body  110 . 
     In the tantalum capacitor  1000  according to the present disclosure, the tantalum wire  150  may penetrate through at least a portion of the tantalum body  100  in the first direction X. In the first cross-section  1000 A partially overlapping the sintered tantalum body  110 , among cross-sections perpendicular to the first direction X, a ratio of an area of the first filler  121  to an area of the conductive polymer layer  120  may be greater than 0.38 or may be 0.55 or more. 
     In addition, in the first cross-section  1000 A, the ratio of the area of the first filler  121  to the area of the conductive polymer layer  120  may be less than 0.83. 
     The term “area” of the conductive polymer layer  120  or the first filler  121  may refer to an area occupied by each element on the first cross-section  1000 A. In the present disclosure, the first filler  121  is an element included in the conductive polymer layer  120 , so that the area of the conductive polymer layer  120  may be interpreted as including the area of the first filler  121 . For example, the area of the first filler  121  cannot be larger than the area of the conductive polymer layer  120 . 
     In the present disclosure, the second filler  122  to be described later is also an element included in the conductive polymer layer  120 , so that the area of the conductive polymer layer  120  may be interpreted as including both the area of the first filler  121  and the area of the second fillers  122 . For example, in the description of the “area” of the present disclosure, the area of each of the first and second fillers  121  and  122  or the sum of the areas of the first and second fillers  121  and  122  cannot be larger than the area of the conductive polymer layer  120 . 
     The Table 1 illustrates characteristics of the tantalum capacitor  1000  depending on the ratio of the area of the first filler  121  to the area of the conductive polymer layer  120  in the first cross-section  1000 A partially overlapping the sintered tantalum body  110 , among cross-sections perpendicular to the first direction X. The moisture absorption rate was evaluated by a rate of change in weight measured after 90 minutes or more elapsed in an environment at a temperature of 85° C. and relative humidity of 85% as a moisture absorption rate. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Ratio of Area 
                 Equivalent 
                 Moisture 
                   
               
               
                   
                 of First 
                 Series 
                 Absorption Rate 
                 Leakage 
               
               
                   
                 Filler to Area 
                 Resistance 
                 of Conductive 
                 Current 
               
               
                   
                 of Conductive 
                 (ESR, 
                 Polymer Layer 
                 (LC, 
               
               
                   
                 Polymer Layer 
                 mΩ) 
                 (%) 
                 μA) 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Comparative 
                 0 
                 105 
                 16.5 (10 or 
                 2.04 
               
               
                 Example 1 
                   
                   
                 more NG) 
               
               
                 Comparative 
                 0.23 
                 104 
                 14 (10 or 
                 1.95 
               
               
                 Example 2 
                   
                   
                 more NG) 
               
               
                 Comparative 
                 0.38 
                 104 
                 11.5 (10 or 
                 1.82 
               
               
                 Example 3 
                   
                   
                 more NG) 
               
               
                 Embodiment 1 
                 0.55 
                 103 
                 8.9 
                 1.71 
               
               
                 Embodiment 2 
                 0.64 
                 103 
                 7.4 
                 1.63 
               
               
                 Embodiment 3 
                 0.71 
                 103 
                 6.1 
                 1.62 
               
               
                 Embodiment 4 
                 0.75 
                 103 
                 5.1 
                 1.60 
               
               
                 Embodiment 5 
                 0.78 
                 109 
                 4.6 
                 1.54 
               
               
                 Embodiment 6 
                 0.81 
                 118 
                 4.0 
                 1.53 
               
               
                 Comparative 
                 0.83 
                 135 (NG) 
                 3.7 
                 1.41 
               
               
                 Example 4 
               
               
                   
               
            
           
         
       
     
     As illustrated in Table 1, when the ratio of the area of the first filler  121  to the area of the conductive polymer layer  120  in a cross-section partially overlapping the sintered tantalum body  110 , among cross-sections perpendicular to the first direction X, for example, the first cross-section  1000 A, is 0.38 or less, an moisture absorption rate of the conductive polymer layer  120  may be increased to 10% or more to deteriorate reliability of the tantalum capacitor  1000 . 
     In terms of equivalent series resistance (ESR), when the ratio of the area of the first filler  121  to the area of the conductive polymer layer  120  in the first cross-section  1000 A is 0.83 or more, ESR may be increased by 30% or more, as compared with Comparative Example 1 in which a filler is not contained, to deteriorate the reliability of the tantalum capacitor  1000 . 
     As described above, in the tantalum capacitor  1000  according to the present disclosure, the ratio of the area of the first filler  121  to the area of the conductive polymer layer  120  in a cross-section partially overlapping the sintered tantalum body  110 , among cross-sections perpendicular to the first direction X, for example, the first cross-section  1000 A may be maintained to be more than 0.38 to less than 0.83, in detail, 0.55 or more to 0.81 or less. Thus, the moisture absorption rate of the conductive polymer layer  120  may be reduced within a range, in which the ESR is not increased by 30% or more, to improve characteristics of the tantalum capacitor  1000 . 
     Referring to the cross-sectional view of the region “A” of  FIG.  4   , the first filler  121  may be dispersed in the conductive polymer layer  120 . In addition, as described later, the second filler  122  may also be dispersed in the conductive polymer layer  120 . 
     The conductive polymer layer  120  in the present disclosure may further include a second filler  122  including one or more conductive particles, among graphene, carbon nanotubes, and black carbon. Since the conductive polymer layer  120  includes the second filler  122  formed of conductive particles, a thickness of the conductive polymer layer  120  in a central portion of the sintered tantalum body  110  may be easily adjusted. 
     For example, one or more conductive particles, among graphene, carbon nanotubes, and black carbon, may cause a coffee ring effect in a process of forming the conductive polymer layer  120  on the sintered tantalum body  110 . 
     For example, polymer slurry containing one or more conductive particles, among graphene, carbon nanotubes, and black carbon, starts to be evaporated from an edge surface of the sintered tantalum body  110 . Particle density may be increased in a portion in which evaporation occurs first. Surrounding slurries and particles may be further pulled due to the increased particle density and high solid content, so that a thickness of the conductive polymer layer  120 , disposed in a corner portion of the sintered tantalum body  110 , may be increased to facilitate control of the thickness. 
     According to an exemplary embodiment, the conductive polymer layer  120  may selectively select particles having different conductivities, among graphene, carbon nanotubes, and black carbon, so that equivalent series resistance (ESR) of the tantalum capacitor may be adjusted to a desired level. 
     An average particle size of the first and second fillers  121  and  122  may be 100 nm or more to 1 μm or less, in detail, 40 nm or more to 5 μm or less, but exemplary embodiments are not limited thereto. 
       FIG.  5    is a cross-sectional view taken along line I-I′ of  FIG.  2    and illustrating a method of measuring a content of a filler in a conductive polymer layer according to the present disclosure. 
       FIG.  5    is an enlarged view of region “B” of  FIG.  4   . 
       FIG.  5    illustrates a method of measuring a ratio of an area of the first filler  121  to an area of the conductive polymer layer  120  in a cross-section partially overlapping the sintered tantalum body  110 , among cross-sections perpendicular to the first direction X, for example, the first cross-section  1000 A, as described above. 
     In the tantalum capacitor  1000  according to the present disclosure, the phrase “ratio of the area of the first filler  121  to the area of the conductive polymer layer  120  in the first cross-section  1000 A” may refer to an average value of ratios of the area of the first filler  121  to the area of the conductive polymer layer  120  measured in a plurality of regions according to a measurement method to be described later. 
     As described above, the first cross-section  1000 A may cut a length of the sintered tantalum body  110  in the first direction X by 2:1. In the conductive polymer layer  120  exposed to the first cross-section  1000 A, ten points spaced apart from each other may be selected to measure the ratio of the area of the first filler  121  to the area of the conductive polymer layer  120 . 
     According to an example of the measurement method of  FIG.  5   , a square-shaped region having ten points, spaced apart from each other, as centers of gravity in an extension line, connecting a ⅓ point of the thickness of the conductive polymer layer, in the first cross-section  1000 A may be selected and designated as a plurality of first regions  120 A. In the example of  FIG.  5   , six first regions  120 A are selected at a boundary dividing a width W of the tantalum body  100  into four equal lengths, and four first regions  120 A are selected at a boundary dividing a thickness T of the tantalum body  100  into three equal thicknesses. That is, ten points spaced apart from each in a conductive polymer layer  120  may be selected. In addition, although the number of the first regions  120 A has been described as being ten, it may be less or more than ten. 
     In this case, the first region  120 A may be in the form of a square having a corner length (or edge length) of 5 μm. Then, the ratio of the area of the first filler  121  to the area of the conductive polymer layer  120  in each of the plurality of first regions  120 A may be measured using an measurement apparatus such as a scanning electron microscope (SEM). When the ratio is measured, the magnification of the SEM may be *15,000 or more and an acceleration voltage may be 10 kV or more. However, the magnification and the acceleration voltage may vary as necessary. 
       FIG.  6    is an enlarged view of region “B” of  FIG.  5   . As illustrated in  FIG.  6   , the plurality of first regions  120 A may be in the form of squares spaced apart from each other. In this case, each of the first regions  120 A may be in the form of a square of which a center of gravity is disposed on an extension line connecting a ⅓ point of a thickness of a conductive polymer layer. 
     For example, when the thickness of the conductive polymer layer  120  is 3 t, as shown in  FIG.  6   , the center of gravity of a square representing each of the first regions  120 A may be disposed a virtual extension line the thickness 3 t of the conductive polymer layer  120  by t:2 t, as illustrated in  FIG.  6   . 
     The average value of the ratios of the area of the first filler  121  to the area of the conductive polymer layer  120 , measured in the plurality of first regions  120 A by the above-described method, may refer to a ratio of an area of the first filler  121  to an area of the conductive polymer layer  120  in the tantalum capacitor  1000  according to the present disclosure. 
     As described above, a tantalum capacitor having reliability improved by reducing a moisture absorption rate without increasing equivalent series resistance may be provided. 
     In addition, a tantalum capacitor having reliability improved in a high-temperature or high-humidity environment may be provided. 
     While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present disclosure as defined by the appended claims.