Tantalum capacitor and method for manufacturing tantalum capacitor
By introducing interface compounds between the components of tantalum capacitors, the reliability and stability issues caused by moisture penetration are resolved, achieving high reliability and stability for tantalum capacitors.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SAMSUNG ELECTRO MECHANICS CO LTD
- Filing Date
- 2025-10-17
- Publication Date
- 2026-06-16
Smart Images
Figure CN122224686A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a tantalum capacitor and a method for manufacturing a tantalum capacitor. Background Technology
[0002] Tantalum capacitors are electronic components used in a variety of passive component-intensive products, such as televisions (TVs), mobile devices, laptops, tablets, digital cameras, medical devices, and automotive electronic components.
[0003] Tantalum (Ta) materials are widely used across industries, including electrical, electronic, mechanical, and chemical engineering, as well as aerospace and military fields, due to their excellent mechanical and physical properties, such as high melting point, ductility, and corrosion resistance. These tantalum materials are widely used as cathode materials for small capacitors because of their ability to form stable positive oxide films, and their use is rapidly increasing annually due to the rapid development of the information technology (IT) industry, such as electronics and information communication.
[0004] Recently, as electronic products have become increasingly dense and thin, there is a need to improve the operational reliability and stability of tantalum capacitors. Summary of the Invention
[0005] According to one aspect of this disclosure, a tantalum capacitor with improved reliability and stability can be provided.
[0006] However, the problems to be solved by the embodiments are not limited to those described above, and various extensions can be made within the scope of the technical concepts included in the embodiments.
[0007] An embodiment provides a tantalum capacitor, the tantalum capacitor comprising: a capacitor body including a tantalum body, a tantalum wire connected to the tantalum body, and a covering portion surrounding the tantalum body and the tantalum wire; and an external electrode located outside the capacitor body. At least one of the regions between the tantalum wire and the covering portion and the regions between the external electrode and the covering portion includes an interface compound, the interface compound including at least one selected from the group consisting of compounds including CH bonds and Si-C bonds, compounds including Si-O-Si bonds, and compounds including CO bonds.
[0008] The capacitor body may further include a base layer and a lower electrode, the base layer being located below the covering portion, and the lower electrode being located between the base layer and the tantalum body.
[0009] The region between the lower electrode and the substrate layer may include the interface compound.
[0010] The capacitor body may further include a conductive bonding layer, which is located between the tantalum body and the outer electrode, and between the tantalum body and the lower electrode.
[0011] Compounds containing CH bonds and Si-C bonds can be derived from aminosilane compounds.
[0012] Compounds containing Si-O-Si bonds can be derived from organosilicon compounds.
[0013] Compounds containing CO bonds can be derived from epoxides.
[0014] The capacitor body may have a first surface and a second surface opposite to each other in a first direction, a third surface and a fourth surface opposite to each other in a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface opposite to each other in a third direction and connecting the first surface and the second surface, as well as the third surface and the fourth surface, and the external electrode may include a first external electrode located on the first surface and a second external electrode located on the second surface.
[0015] The first external electrode can be connected to the tantalum wire.
[0016] The capacitor body may further include a base layer and a lower electrode. The base layer is located below the covering portion, the lower electrode is located between the base layer and the tantalum body, and the second external electrode may be connected to the lower electrode.
[0017] The first external electrode may cover a portion of the sixth surface and the first surface, and the second external electrode may cover another portion of the sixth surface and the second surface.
[0018] The coating may include epoxy resin.
[0019] Another embodiment provides a method for manufacturing a tantalum capacitor, the method comprising: preparing a tantalum capacitor precursor including a capacitor body and an external electrode located on a surface of the capacitor body, the capacitor body including a tantalum body, a tantalum wire connected to the tantalum body, and a covering portion surrounding the tantalum body and the tantalum wire; and manufacturing the tantalum capacitor by vacuum impregnating the tantalum capacitor precursor with at least one selected from the group consisting of aminosilane compounds, organosilicon compounds, and epoxy compounds. At least one of the regions between the tantalum wire and the covering portion and the regions between the external electrode and the covering portion includes an interface compound, the interface compound including at least one selected from the group consisting of compounds including CH bonds and Si-C bonds, compounds including Si-O-Si bonds, and compounds including CO bonds.
[0020] According to embodiments of this disclosure, moisture penetration between the various components of a tantalum capacitor can be suppressed, thereby improving the reliability and stability of the tantalum capacitor.
[0021] According to the embodiments, moisture penetration into the tiny spaces of the tantalum capacitor can be suppressed, thereby suppressing corrosion, peeling, and open defects of the metal components. Attached Figure Description
[0022] Figure 1 A perspective view of a tantalum capacitor according to an embodiment is shown schematically.
[0023] Figure 2 It shows along Figure 1 A cross-sectional view of the tantalum capacitor according to the embodiment, taken by line I-I'.
[0024] Figure 3 It shows along Figure 1 A cross-sectional view of a tantalum capacitor according to another embodiment, taken by line I-I'.
[0025] Figure 4 , Figure 6 and Figure 7 Fourier transform infrared (FT-IR) analysis plots of tantalum capacitors in Examples 1 and 3 and the comparative example are shown respectively.
[0026] Figure 5 The Raman spectrum analysis diagram of Example 2 is shown.
[0027] Figure 8 The results of high-acceleration stress tests for each of the tantalum capacitors in Examples 1 to 3 and the comparative example are shown in graphs. Detailed Implementation
[0028] The present disclosure will be described more fully below with reference to the accompanying drawings, in which embodiments of the disclosure are illustrated. The drawings and description are to be considered illustrative rather than restrictive in nature. Throughout the specification, the same reference numerals denote the same elements. Additionally, in the drawings, some components are shown enlarged, omitted, or abbreviated, and the dimensions of the individual components do not reflect their actual dimensions.
[0029] The accompanying drawings are provided only to facilitate a good understanding of the embodiments disclosed in this specification and are not to be construed as limiting the technical spirit disclosed herein. It should be understood that this disclosure includes all variations, equivalents and alternatives without departing from the scope and spirit of this disclosure.
[0030] Ordinal terms such as "first" and "second" can be used to describe various elements, but elements are not limited by these terms. These terms are only used to distinguish one constituent element from another.
[0031] It should be understood that when an element such as a layer, film, region, area, or substrate is referred to as being "on" another element, the element may be directly on the other element, or there may be an intermediate element located between them. In contrast, when an element is referred to as being "directly on" another element, there is no intermediate element. Furthermore, in the specification, the terms "on" the target portion or "above" the target portion indicate that it is disposed above or below the target portion, and do not necessarily mean that it is disposed on the upper side of the target portion based on the direction of gravity.
[0032] Throughout this specification, it should be understood that the terms "comprising," "including," "having," or "construction" indicate the presence of the features, quantities, steps, operations, constituent elements, components, or combinations thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, quantities, steps, operations, constituent elements, components, or combinations thereof. Unless expressly stated to the contrary, the words "comprising," "including," and "having" will be understood to imply the inclusion of the stated elements but not the exclusion of any other elements.
[0033] Furthermore, throughout the specification, the phrase "in plan view" or "on a plane" indicates the target portion as viewed from the top, and the phrase "in section view" or "on a section" indicates the section formed by vertically cutting the target portion as viewed from the side.
[0034] Furthermore, throughout the specification, the term "connection" may refer not only to a direct connection between two or more elements, but also to a connection between two or more elements indirectly through other elements, or to a physical and / or electrical connection between two or more elements. Additionally, it may include cases where the individual components are referred to by different names depending on their location or function, but are substantially integrally connected to each other.
[0035] Figure 1 A perspective view of a tantalum capacitor according to an embodiment is shown schematically. Figure 2 It shows along Figure 1 A cross-sectional view of the tantalum capacitor according to the embodiment, taken by line I-I'.
[0036] The L-axis, W-axis, and T-axis directions shown in the attached figures represent the length, width, and thickness directions of the tantalum capacitor 100 and the capacitor body 110, respectively.
[0037] The length direction (L-axis direction) can be substantially perpendicular to the thickness direction (T-axis direction). For example, the length direction (L-axis direction) can represent the direction along which the tantalum wire 112 extends. The width direction (W-axis direction) can be substantially perpendicular to both the thickness direction (T-axis direction) and the length direction (L-axis direction). The dimension (i.e., length) of the tantalum capacitor 100 or capacitor body 110 in the length direction (L-axis direction) can be larger than the dimension (i.e., width) of the tantalum capacitor 100 or capacitor body 110 in the width direction (W-axis direction).
[0038] In this specification, the first direction and the aforementioned length direction (L-axis direction) may have the same meaning, the second direction and the aforementioned width direction (W-axis direction) may have the same meaning, and the third direction and the aforementioned stacking direction (T-axis direction) may have the same meaning.
[0039] In the following text, for better understanding and ease of description, in the capacitor body 110, two surfaces opposite to each other in a first direction are defined as a first surface and a second surface, two surfaces connected to the first surface and the second surface and opposite to each other in a second direction are defined as a third surface and a fourth surface, and two surfaces connected to the first surface and the second surface and connected to the third surface and the fourth surface and opposite to each other in a third direction are defined as a fifth surface and a sixth surface.
[0040] Reference Figure 1 and Figure 2 The tantalum capacitor 100 according to the embodiment may include a capacitor body 110.
[0041] The capacitor body 110 may include a tantalum body 111 and tantalum wires 112 connected to the tantalum body 111.
[0042] The shape of the tantalum body 111 may include pellet, sponge, sheet, foil, etc.
[0043] The tantalum body 111 can be formed using tantalum (Ta) metal or tantalum powder.
[0044] Tantalum powder can be produced by reacting tantalum salts (such as potassium fluorotantalate (K2TaF7), sodium fluorotantalate (Na2TaF7), or tantalum pentachloride (TaCl5)) with a reducing agent. These components can be used alone or in combination of two or more.
[0045] Tantalum powder and binder can be mixed in a predetermined ratio. The mixed powder can be pressed to mold into a cuboid shape or other suitable shape. The molded body can be sintered under high temperature and high vacuum conditions to manufacture the tantalum body 111.
[0046] According to an embodiment, the tantalum wire 112 can be inserted into the tantalum body 111 to protrude from one side surface of the tantalum body 111. The tantalum wire 112 can extend to contact a first surface of the capacitor body 110 (e.g., based on...). Figure 2 (The left side surface of the capacitor body 110).
[0047] When manufacturing the tantalum body 111, a portion of the tantalum wire 112 can be inserted into a mixture of tantalum powder and binder along the length direction (L-axis direction), and then the tantalum wire 112 and the tantalum body 111 can be molded and sintered together. For example, the tantalum wire 112 can be inserted so that the tantalum wire 112 is located at the center of the tantalum body 111 in the thickness direction (T-axis direction).
[0048] The tantalum wire 112 can be a tantalum metal rod in the shape of a rod or strip. For example, the tantalum wire 112 can be used as the anode of a tantalum capacitor.
[0049] A dielectric layer (not shown) may be disposed on the surface of the tantalum body 111. The dielectric layer may be formed by anodizing the tantalum capacitor 100.
[0050] For example, the dielectric layer may include an oxide of tantalum metal, such as tantalum pentoxide (Ta2O5).
[0051] For example, the capacitor body 110 may also include a solid electrolyte layer (not shown) disposed on the surface of the tantalum body 111.
[0052] A solid electrolyte layer can be formed on the surface of a dielectric layer by immersing a tantalum body 111, on which a dielectric layer is disposed, in a polymerization solution and reacting it in a polymerization furnace. The solid electrolyte layer can be used as the cathode of a tantalum capacitor. Therefore, the tantalum body 111 can be used as the cathode of a tantalum capacitor.
[0053] The solid electrolyte layer may include a conductive polymer, manganese dioxide (MnO2), or a combination thereof.
[0054] When the solid electrolyte layer comprises a conductive polymer, the solid electrolyte layer can be formed on the surface of the dielectric layer by chemical polymerization or electrolytic polymerization. There are no particular limitations on the material of the conductive polymer, as long as it is a conductive polymer material; for example, it may include polypyrrole, polythiophene, polyacetylene, and / or polyaniline.
[0055] When the solid electrolyte layer includes manganese dioxide (MnO2), the tantalum substrate 111 can be immersed in a manganese-containing aqueous solution (such as manganese nitrate), and then the manganese-containing aqueous solution can be thermally decomposed to form conductive manganese dioxide on the surface of the dielectric layer. The composition of the manganese-containing aqueous solution is not particularly limited, as long as its thermal decomposition forms conductive manganese dioxide on the surface of the dielectric layer.
[0056] For example, the solid electrolyte layer may include an acid such as p-toluenesulfonic acid (P-TSA).
[0057] Depending on the acidic composition, the solid electrolyte layer can combine with moisture under high temperature and high humidity load conditions, thereby causing corrosion of the internal metal. However, according to embodiments of this disclosure, moisture penetration between the various components of the tantalum capacitor 100 can be suppressed, thereby improving the reliability and stability of the tantalum capacitor 100.
[0058] The capacitor body 110 may further include a cathode reinforcement layer (not shown) disposed on the surface of the tantalum body 111 or the surface of the solid electrolyte layer. The cathode reinforcement layer may include a carbon layer and a silver (Ag) layer. For example, the carbon layer and the silver layer may be stacked sequentially on the solid electrolyte layer. The carbon layer can reduce the contact resistance of the surface of the tantalum body 111. The silver layer can improve the conductivity of the tantalum capacitor 100.
[0059] The solid electrolyte layer and the cathode reinforcement layer are insulated from the tantalum wire 112. Therefore, the cathode and anode of the tantalum capacitor 100 are insulated from each other, thereby preventing short circuits.
[0060] In some embodiments, the capacitor body 110 may further include a covering portion 113 that accommodates the tantalum body 111 and the tantalum wire 112.
[0061] The covering portion 113 may surround the tantalum body 111 and the tantalum wire 112. Therefore, the tantalum body 111 and the tantalum wire 112 can be protected from external impact or contamination.
[0062] The covering portion 113 may include epoxy resin. For example, the covering portion 113 may include a photocurable epoxy resin surrounding the capacitor body 110. For example, the epoxy resin may include epoxy molding compound (EMC) or the like. For example, the covering portion 113 may be formed by transfer molding, vacuum forming, compression molding, or the like with the epoxy resin.
[0063] The tantalum capacitor 100 may also include external electrodes 131 and 132 located outside the capacitor body 110.
[0064] External electrodes 131 and 132 may include: a first external electrode 131 located on a first surface of the capacitor body 110 (e.g., based on...). Figure 2 The capacitor body 110 is located on the left side surface of the capacitor body 110; and the second external electrode 132 is located on the second surface of the capacitor body 110 opposite to the first surface (e.g., based on the left side surface of the capacitor body 110). Figure 2 On the right side surface of the capacitor body 110.
[0065] The first external electrode 131 may be connected to the tantalum wire 112. For example, the first external electrode 131 may be located on a first surface to contact the tantalum wire 112 exposed on the first surface of the capacitor body 110. At least a portion of the first external electrode 131 may be configured as the anode terminal of the tantalum capacitor 100.
[0066] The second external electrode 132 can be electrically connected to the solid electrolyte layer and / or cathode reinforcement layer disposed on the surface of the tantalum body 111 via the lower electrode 115 and / or conductive bonding layer 116, which will be described later. For example, the second external electrode 132 may be located on a second surface to contact the lower electrode 115 and / or conductive bonding layer 116, which in turn contacts the second surface of the capacitor body 110. At least a portion of the second external electrode 132 may be configured as the cathode terminal of the tantalum capacitor 100.
[0067] The first external electrode 131 may cover the sixth surface of the capacitor body 110 (e.g., based on...). Figure 2 The second external electrode 131 may cover a portion of the lower surface of the capacitor body 110 and the first surface of the capacitor body 110, and the second external electrode 132 may cover another portion of the sixth surface of the capacitor body 110 and the second surface of the capacitor body 110. The portion of the first external electrode 131 located on the sixth surface and the portion of the second external electrode 132 located on the sixth surface may be spaced apart from each other in the length direction (L-axis direction) to be respectively configured as an anode terminal and a cathode terminal.
[0068] The external electrodes 131 and 132 may include Ta, W, Ni, Cr, alloys of these metals, or mixtures thereof. These components may be used alone or in combination of two or more.
[0069] External electrodes 131 and 132 can be formed on the capacitor body 110 by sputtering, but are not limited thereto.
[0070] Since the tantalum capacitor 100 does not include a separate connecting frame and the external electrodes 131 and 132 are configured as terminals, the space efficiency of the tantalum capacitor 100 can be improved. Additionally, the dimensions of the tantalum body 111 and the tantalum wire 112 can be increased, thereby further improving the capacitance characteristics and low resistance characteristics of the tantalum capacitor 100.
[0071] The tantalum capacitor 100 according to an embodiment of the present disclosure may further include an interface compound located in the region between the tantalum wire 112 and the cover portion 113. Figure 2 Region B) and the region between the outer electrodes 131 and 132 and the covering portion 113 ( Figure 2The interface compound may include at least one of the following: (region A). The interface compound may include at least one selected from the group consisting of compounds comprising CH bonds and Si-C bonds, compounds comprising Si-O-Si bonds, and compounds comprising CO bonds. The interface compound can inhibit the penetration of moisture into the minute spaces of the tantalum capacitor 100, thereby inhibiting corrosion, peeling, and opening defects of the metal components in the tantalum capacitor 100.
[0072] In the context of this disclosure, the phrase “between X and Y” can refer to a small space in contact with the interface between X and Y or a small space between adjacent surfaces of X and Y.
[0073] Compounds containing CH bonds and Si-C bonds can be derived from aminosilane compounds. Compounds containing Si-O-Si bonds can be derived from organosilicon compounds. Compounds containing CO bonds can be derived from epoxide compounds.
[0074] In order to manufacture the tantalum capacitor 100 according to the embodiment, a tantalum capacitor precursor including a capacitor body 110 and external electrodes 131 and 132 may be prepared.
[0075] The tantalum capacitor 100 can be manufactured by vacuum impregnating a tantalum capacitor precursor with at least one selected from the group consisting of aminosilane compounds, organosilicon compounds, and epoxy compounds. Through vacuum impregnation, an interface compound can be filled in the region between the aforementioned components. Therefore, moisture penetration through the internal regions is inhibited, thereby reducing corrosion and opening defects and improving the reliability of the tantalum capacitor 100.
[0076] Aminosilane compounds may include 3-aminopropyltrimethoxysilane (APTMS) and 3-aminopropyltriethoxysilane (APTES). These components may be used alone or in combination of two or more.
[0077] Organosilicon compounds may include KJF-810 from Shin-Etsu Silicone Co., Ltd.
[0078] Epoxy compounds can include bisphenol A type epoxy resins, phenolic type epoxy resins, etc. These components can be used alone or in combination of two or more.
[0079] In some embodiments, the capacitor body 110 may further include a base layer 114 located below the cover portion 113. For example, the bottom surface of the base layer 114 may be configured as the sixth surface of the capacitor body 110.
[0080] The substrate 114 supports the combination of the tantalum body 111, the tantalum wire 112, and the covering portion 113. Therefore, the structural stability of the tantalum capacitor 100 can be further improved.
[0081] The base layer 114 may include insulating materials such as curable resins and inorganic fillers. These components may be used alone or in combination of two or more.
[0082] Curable resins may include cresol-phenolic epoxy resins, bisphenol A type epoxy resins, bisphenol A type phenolic epoxy resins, phenolic epoxy resins, multifunctional epoxy resins, biphenyl type epoxy resins, xylene type epoxy resins, pyromellitic methane type epoxy resins, alkyl-modified pyromellitic methane epoxy resins, naphthalene type epoxy resins, dicyclopentadiene type epoxy resins, and dicyclopentadiene-modified phenol type epoxy resins, etc. These components can be used alone or in combination of two or more.
[0083] Inorganic fillers may include silica (SiO2), alumina (Al2O3), silicon carbide (SiC), barium sulfate (BaSO4), talc, clay, mica powder, aluminum hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), calcium carbonate (CaCO3), magnesium carbonate (MgCO3), magnesium oxide (MgO), boron nitride (BN), aluminum borate (AlBO3), barium titanate (BaTiO3), and calcium zirconate (CaZrO3). These components may be used alone or in combination of two or more. Inorganic fillers can improve the strength of the substrate 114 and reduce its thickness.
[0084] In some embodiments, the capacitor body 110 may further include a lower electrode 115 located between the substrate layer 114 and the tantalum body 111. The lower electrode 115 may include metals such as copper (Cu) and nickel (Ni).
[0085] One end of the lower electrode 115 can contact the second surface of the capacitor body 110 to be electrically connected to the second external electrode 132. Through the lower electrode 115, the second external electrode 132 can be electrically connected to the components of the tantalum capacitor 100 that serve as the cathode (e.g., solid electrolyte layer, cathode enhancement layer, etc.).
[0086] The aforementioned interface compound may be located in at least one of the following regions: the region between the tantalum wire 112 and the cover portion 113, the region between the outer electrodes 131 and 132 and the cover portion 113, and the region between the lower electrode 115 and the substrate layer 114. The region between the lower electrode 115 and the substrate layer 114 may include the region between the cover portion 113 and the substrate layer 114. The interface compound prevents moisture penetration and corrosion between the lower electrode 115 and the substrate layer 114. Therefore, the durability and reliability of the tantalum capacitor 100 can be further improved.
[0087] The presence of the aforementioned interface compounds can be confirmed by Fourier transform infrared (FT-IR) analysis or Raman spectroscopy analysis. A cross-section (LT section) obtained by cutting from the center of the tantalum capacitor 100 along its length direction (L-axis) and thickness direction (T-axis) perpendicular to the width direction can be exposed. The exposure process can be performed by polishing with a polishing machine. In the LT section, the region between the tantalum line 112 and the covering portion 113 ( Figure 2 Region B), the region between the outer electrodes 131 and 132 and the covering portion 113 ( Figure 2 Region A) or the region between the lower electrode 115 and the substrate 114 ( Figure 2 Ten points, evenly spaced, are designated within the C region. The presence of chemical bonds can be confirmed by performing FT-IR or Raman spectroscopy at these designated points. The presence of both CH and Si-C bonds is evaluated as the presence of a compound containing both CH and Si-C bonds when both are detected. The presence of Si-O-Si bonds is evaluated as the presence of a compound containing Si-O-Si bonds when both are detected. The presence of CO bonds is evaluated as the presence of a compound containing CO bonds when the above chemical bonds are detected at five or more of the ten points. An interfacial compound is evaluated as being present.
[0088] Figure 3 It shows along Figure 1 A cross-sectional view of a tantalum capacitor according to another embodiment, taken by line I-I'.
[0089] Reference Figure 3 The capacitor body 110 may further include a conductive bonding layer 116 located between the tantalum body 111 and the second external electrode 132, and between the tantalum body 111 and the lower electrode 115. Therefore, the bonding strength between the tantalum body 111, the lower electrode 115, and the second external electrode 132 can be improved, thereby further improving the structural stability and operational reliability of the tantalum capacitor 100.
[0090] The conductive bonding layer 116 may include a conductive binder comprising an epoxy resin and a conductive metal powder (e.g., silver (Ag)).
[0091] Specific examples of this disclosure will be described below.
[0092] Example 1 Manufacturing with Figure 1 and Figure 2 The tantalum capacitor shown is a tantalum capacitor with the structure shown.
[0093] Specifically, granulated tantalum powder (as tantalum powder) is mixed with camphor (as a binder) to form a mixture, and tantalum wires are inserted into the mixture. The mixture with the inserted tantalum wires is then formed into a molded body with a cuboid shape and sintered to manufacture a tantalum body with the inserted tantalum wires.
[0094] A Cu-plated lower electrode is bonded to the first surface of a substrate (FR4 substrate). The tantalum capacitor precursor, including the encapsulation portion, is manufactured by fixing the bottom surface of the tantalum body and the lower electrode into contact with each other, and molding EMC on the substrate to cover the tantalum body, tantalum wires, and lower electrode. The FR4 substrate can be interpreted as commonly used in the art. For example, FR4 substrate refers to an insulating material having a structure in which multilayer glass fibers impregnated with epoxy resin are stacked.
[0095] Tantalum capacitor precursors are vacuum impregnated in 3-aminopropyltrimethoxysilane (APTMS) to manufacture tantalum capacitors that include interface compounds.
[0096] Example 2 Except for the use of Shin-Etsu Silicone Co., Ltd.'s KJF-810 to replace APTMS for vacuum impregnating tantalum capacitor precursors, tantalum capacitors are manufactured in the same manner as in Example 1.
[0097] Example 3 The tantalum capacitor is manufactured in the same manner as in Example 1, except that bisphenol A type epoxy resin is used instead of APTMS for vacuum impregnation of the tantalum capacitor precursor.
[0098] Comparative example Except for using a tantalum capacitor precursor as the final tantalum capacitor without performing vacuum impregnation, the tantalum capacitor is manufactured in the same manner as in Example 1.
[0099] Evaluation 1: FT-IR analysis Epoxy resin is used to fix the tantalum capacitors of the above examples and comparative examples around them.
[0100] The tantalum capacitor is polished using a polishing machine to expose a cross section (LT section) obtained by cutting from the center of the tantalum capacitor along the length direction (L-axis direction) and thickness direction (T-axis direction) perpendicular to the width direction.
[0101] FT-IR analysis was performed on 10 points in each of the following regions of the LT section: the region between the outer electrode and the cladding ( Figure 2 Region A), the area between the tantalum wire and the cladding ( Figure 2Region B) and the region between the lower electrode and the substrate ( Figure 2 (C region). Analysis was performed at 10 points to check for the detection of CH bonds and Si-C, Si-O-Si, or CO bonds. If CH bonds and Si-C, Si-O-Si, or CO bonds were detected at five or more points, the presence of an interfacial compound was assessed. If CH bonds and Si-C, Si-O-Si, or CO bonds were detected at fewer than 5 points (including 0), the absence of an interfacial compound was assessed.
[0102] FT-IR analysis was performed using a Nicolet iN10 infrared microscope from Thermo Fisher Scientific under the following conditions: spectral range of 650 cm⁻¹. -1 Up to 4000cm -1 Reflection mode, mercury cadmium telluride (MCT) detector, resolution 8 cm⁻¹ -1 And the amount of matter accumulated is 64.
[0103] The evaluation results are shown in Table 1 below. In Table 1, "○" indicates the presence of interfacial compounds, and "X" indicates the absence of interfacial compounds. In Table 1, "-" indicates that no chemical bonds were detected.
[0104] (Table 1)
[0105] The presence of chemical bonds can be detected instead of FT-IR analysis by performing Raman spectroscopy at the same point as the measurement point. The detection results can be evaluated in the same way as FT-IR analysis to assess the presence of interfacial compounds.
[0106] Figure 4 , Figure 6 and Figure 7 FT-IR analysis plots of tantalum capacitors from Example 1, Example 3, and the comparative example are shown respectively. Figure 5 The Raman spectrum analysis diagram of Example 2 is shown.
[0107] Reference Figures 4 to 6 In Example 1, an interfacial compound containing both CH bonds and Si-C bonds was detected; in Example 2, an interfacial compound containing Si-O-Si bonds was detected; and in Example 3, an interfacial compound containing CO bonds was detected.
[0108] Reference Figure 7 In the comparative example, in the region between the outer electrode and the covering portion ( Figure 2 Region A), the area between the tantalum wire and the cladding ( Figure 2Region B) and the region between the lower electrode and the substrate ( Figure 2 No interface compounds were detected in the C region.
[0109] Evaluation 2: High Accelerated Stress Test (HAST) The tantalum capacitors of Example 1 and the comparative example above were subjected to high-accelerated stress test (HAST) under high temperature and high humidity conditions.
[0110] Specifically, 40 tantalum capacitors were fabricated, and the capacitance of each capacitor was evaluated for 50 hours at 115°C, 95% relative humidity, and 1VR rated voltage. Failure to achieve proper capacitance was defined as a defect, and the time required for the defect to occur was measured.
[0111] The failure rate is evaluated by expressing the percentage of defective tantalum capacitors out of a total of 40 tantalum capacitors. Figure 8 The failure rate is shown based on the evaluation time.
[0112] Figure 8 The results of the high accelerated stress test (HAST) for each of the tantalum capacitors in Examples 1 to 3 and the comparative example are shown in graphs.
[0113] Reference Figure 8 Compared to the comparative examples, in Examples 1 to 3, the area between the external electrode and the coating was suppressed by the interface compound. Figure 2 Region A), the area between the tantalum wire and the cladding ( Figure 2 Region B) and the region between the lower electrode and the substrate ( Figure 2 Moisture penetration into the C region (of the capacitor) can suppress opening defects and improve the reliability and stability of tantalum capacitors.
[0114] While exemplary embodiments have been shown and described above, it will be readily understood by those skilled in the art that modifications and variations may be made without departing from the scope of this disclosure as defined by the appended claims.
Claims
1. A tantalum capacitor, comprising: A capacitor body includes a tantalum body, tantalum wires connected to the tantalum body, and a covering portion surrounding the tantalum body and the tantalum wires; as well as The external electrode is located outside the capacitor body. Wherein, one or both of the regions between the tantalum wire and the coating portion and the regions between the external electrode and the coating portion include an interface compound, the interface compound including at least one selected from the group consisting of compounds including CH bonds and Si-C bonds, compounds including Si-O-Si bonds and compounds including CO bonds.
2. The tantalum capacitor according to claim 1, wherein, The capacitor body further includes a base layer and a lower electrode. The base layer is located below the encapsulation portion, and the lower electrode is located between the base layer and the tantalum body.
3. The tantalum capacitor according to claim 2, wherein, The region between the lower electrode and the substrate layer includes the interface compound.
4. The tantalum capacitor according to claim 2, wherein, The capacitor body further includes a conductive bonding layer, which is located between the tantalum body and the outer electrode, and between the tantalum body and the lower electrode.
5. The tantalum capacitor according to claim 1, wherein, Compounds containing CH bonds and Si-C bonds are derived from aminosilane compounds.
6. The tantalum capacitor according to claim 1, wherein, Compounds containing Si-O-Si bonds are derived from organosilicon compounds.
7. The tantalum capacitor according to claim 1, wherein, Compounds containing CO bonds are derived from epoxides.
8. The tantalum capacitor according to claim 1, wherein, The capacitor body has a first surface and a second surface opposite to each other in a first direction, a third surface and a fourth surface opposite to each other in a second direction and connecting the first surface and the second surface, and a fifth surface and a sixth surface opposite to each other in a third direction and connecting the first surface and the second surface, as well as the third surface and the fourth surface. The external electrode includes a first external electrode located on the first surface and a second external electrode located on the second surface.
9. The tantalum capacitor according to claim 8, wherein, The first external electrode is connected to the tantalum wire.
10. The tantalum capacitor according to claim 8, wherein, The capacitor body further includes a substrate layer and a lower electrode. The substrate layer is located below the encapsulation portion, and the lower electrode is located between the substrate layer and the tantalum body. The second external electrode is connected to the lower electrode.
11. The tantalum capacitor according to claim 8, wherein, The first external electrode covers a portion of the sixth surface and the first surface, and the second external electrode covers another portion of the sixth surface and the second surface.
12. The tantalum capacitor according to claim 1, wherein, The coating portion includes epoxy resin.
13. A method for manufacturing a tantalum capacitor, comprising: A tantalum capacitor precursor is prepared, comprising a capacitor body and an external electrode located on the surface of the capacitor body. The capacitor body includes a tantalum body, a tantalum wire connected to the tantalum body, and a covering portion surrounding the tantalum body and the tantalum wire. as well as Tantalum capacitors are manufactured by vacuum impregnating the tantalum capacitor precursor with at least one selected from the group consisting of aminosilane compounds, organosilicon compounds, and epoxy compounds. Wherein, one or both of the regions between the tantalum wire and the coating portion and the regions between the external electrode and the coating portion include an interface compound, the interface compound including at least one selected from the group consisting of compounds including CH bonds and Si-C bonds, compounds including Si-O-Si bonds and compounds including CO bonds.
14. The method according to claim 13, wherein, Compounds containing CH bonds and Si-C bonds are derived from the aminosilane compounds.
15. The method according to claim 13, wherein, Compounds containing Si-O-Si bonds are derived from the aforementioned silicon compounds.
16. The method according to claim 13, wherein, Compounds containing CO bonds are derived from the aforementioned epoxy compounds.