Capacitor component
The capacitor component design with alternately arranged internal electrodes and a hexahedral shape addresses piezoelectric stress and lamination issues, enhancing reliability and capacitance in MLCCs.
Patent Information
- Application Number
- JP2024216039
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-12-29
- Filing Date
- 2024-12-10
- Publication Date
- 2025-07-10
AI Technical Summary
Multilayer ceramic capacitors (MLCCs) face issues such as cracks due to piezoelectric expansion and contraction, step differences in electrode lamination, and reduced productivity under high-temperature and high-pressure conditions.
A capacitor component design featuring a dielectric layer and internal electrodes alternately arranged and wound about an axis, with external electrodes on opposing surfaces, and a hexahedral shape to minimize shrinkage and electrode lamination differences, enhancing mechanical strength and capacitance.
Suppresses crack formation and step differences while improving capacitance and productivity by stabilizing the structure under high stress conditions.
Smart Images
Figure 2025105506000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to capacitor components.
Background Art
[0002] A multilayer ceramic capacitor (MLCC), which is one of capacitor components, is an important chip component used in industries such as communication, computer, household appliances, and automobiles due to the advantages of being small in size while ensuring high capacitance. In particular, it is a core passive component used in various electrical, electronic, and information and communication devices such as mobile phones, computers, and digital TVs.
[0003] Such a multilayer ceramic capacitor can be used as a component of various electronic devices due to the advantages of being small in size while ensuring high capacitance and being easy to mount. Recently, with the miniaturization and high-performance of electronic devices, multilayer ceramic capacitors also tend to be miniaturized and have higher capacitance.
[0004] On the other hand, a multilayer ceramic capacitor is formed by laminating a large number of internal electrodes and a first dielectric green sheet. When an MLCC with such a structure operates in a high-temperature and high-pressure environment, cracks may occur due to the shrinkage and expansion (piezoelectric effect) associated with the piezoelectricity of the dielectric layer. In particular, cracks may occur between the internal electrode with insufficient adhesive force and the dielectric, which may cause MLCC failure. In addition, in a conventional multilayer ceramic capacitor, steps may occur in the margin portion due to the difference in the lamination degree of the internal electrodes.
[0005] Therefore, there is a need for a new structure and manufacturing method of capacitor components that can suppress the piezoelectric effect and steps while maintaining the capacitance per unit volume that can be ensured in existing multilayer ceramic capacitors.
Summary of the Invention
Problems to be Solved by the Invention
[0006] One of several objects of the present invention is to suppress expansion and contraction due to the electrostrictive phenomenon and reduce the occurrence of cracks in the capacitor component.
[0007] One of several objects of the present invention is to mitigate the step difference caused by the difference in the lamination degree of the internal electrodes.
[0008] One of several objects of the present invention is to improve the productivity of the capacitor component.
[0009] However, the object of the present invention is not limited to the above content and can be more easily understood in the process of describing the specific embodiments of the present invention.
Means for Solving the Problems
[0010] A capacitor component according to an embodiment of the present invention includes a main body including a dielectric layer and first and second internal electrodes alternately arranged with the dielectric layer therebetween and wound about an axis in a second direction, and external electrodes respectively arranged on a third surface and a fourth surface of the main body facing in the second direction. The main body may further include a first surface and a second surface facing in a first direction perpendicular to the second direction, and a fifth surface and a sixth surface facing in a third direction perpendicular to the first and second directions.
Effects of the Invention
[0011] One of several effects of the present invention is to suppress the occurrence of non-uniform shrinkage behavior in the capacitor component by including the first and second internal electrodes alternately arranged with the dielectric layer therebetween and wound about an axis in the second direction.
[0012] One of several effects of the present invention is to suppress the step difference caused by the formation of a margin portion by removing the difference in the lamination degree of the internal electrodes of the capacitor component.
[0013] However, the diverse yet beneficial advantages and effects of the present invention are not limited to the above-described content and can be more easily understood during the process of explaining the specific embodiments of the present invention.
Brief Description of the Drawings
[0014]
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Modes for Carrying Out the Invention
[0015] Hereinafter, embodiments of the present invention will be described with reference to specific embodiments and the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Also, the embodiments of the present invention are provided to more fully explain the present invention to an ordinary technician. Therefore, the shape and size of elements in the drawings can be exaggerated for a clearer explanation, and elements denoted by the same reference numerals in the drawings are the same elements.
[0016] And, in order to clearly explain the present invention in the drawings, parts not related to the explanation are omitted, and the sizes and thicknesses of each configuration shown in the drawings are arbitrarily shown for convenience of explanation, so the present invention is not necessarily limited to what is shown in the drawings. For components with the same functions within the scope of the same idea, the same reference numerals are used for explanation. Further, throughout the specification, when a certain part says that a certain component "includes", this means that, unless otherwise stated to the contrary, it does not exclude other components, but may further include other components.
[0017] FIG. 1 schematically shows a perspective view of a capacitor component according to an embodiment of the present invention, FIG. 2 schematically shows a perspective view of a main body according to an embodiment of the present invention, FIG. 3 is a cross-sectional view taken along line I-I' of FIG. 1, and FIG. 4 is a cross-sectional view taken along line II-II' of FIG. 1.
[0018] Hereinafter, a capacitor component 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4.
[0019] The capacitor component 100 according to an embodiment of the present invention includes a main body 110 including a dielectric layer 111 and first and second internal electrodes 121 and 122 that are alternately arranged with the dielectric layer interposed therebetween and wound around an axis in a second direction, and external electrodes 131 and 132 respectively arranged on a third surface 3 and a fourth surface 4 of the main body facing the second direction. The main body may further include a first surface 1 and a second surface 2 facing each other in a first direction perpendicular to the second direction, and a fifth surface 5 and a sixth surface 6 facing each other in a third direction perpendicular to the first direction and the second direction.
[0020] The main body 110 may include a dielectric layer 111 and first and second internal electrodes 121 and 122 that are alternately arranged with the dielectric layer interposed therebetween and wound around an axis in a second direction.
[0021] There is no particular limitation on the specific shape of the main body 110. As shown in the figure, the main body 110 can be substantially in a hexahedron shape or a shape similar thereto. Due to the shrinkage of the ceramic powder contained in the main body 110 during the firing process, the main body 110 can be substantially in a hexahedron shape rather than a hexahedron shape consisting of a complete plane. Specifically, the main body 110 may include a third surface 3 and a fourth surface 4 facing each other in a second direction, a first surface 1 and a second surface 2 facing each other in a first direction perpendicular to the second direction, and a fifth surface 5 and a sixth surface 6 facing each other in a third direction perpendicular to the first direction and the second direction.
[0022] Referring to FIGS. 2 and 3, the third surface 3 can be in contact with the first internal electrode 121 and separated from the fourth surface 4, and the fourth surface 4 can be in contact with the second internal electrode 122 and separated from the third surface 3. Thereby, different polarities can be imparted to the first internal electrode 121 and the second internal electrode 122.
[0023] The dielectric layer 111 forming the main body 110 is in a fired state, and the boundary between adjacent dielectric layers 111 can be integrated to such an extent that it is difficult to confirm without using a scanning electron microscope (SEM).
[0024] The dielectric layer 111 can be formed by manufacturing a ceramic slurry containing ceramic powder, an organic solvent, and a binder, applying and drying the slurry on a carrier film to provide a ceramic green sheet, and then firing the ceramic green sheet. The ceramic powder is not particularly limited as long as sufficient capacitance can be obtained. For example, as the ceramic powder, a barium titanate (BaTiO3)-based powder can be used. As a more specific example, the ceramic powder is a barium titanate (BaTiO3)-based powder, such as BaTiO3, (Ba 1-x Ca x )TiO3 (0 < x < 1), Ba(Ti 1-y Ca y )O3 (0 < y < 1), (Ba 1-x Ca x )(Ti 1-y Zr y )O3 (0 < x < 1, 0 < y < 1), and Ba(Ti 1-y Zr y )O3 (0 < y < 1), and one or more of them may be used. In this case, the dielectric layer 111 can contain Ba and Ti.
[0025] The average thickness td of the dielectric layer 111 is not particularly limited.
[0026] For the purpose of miniaturizing and increasing the capacitance of the capacitor component 100, the average thickness td of the dielectric layer 111 may be 1.0 μm or less. To improve the reliability of the capacitor component 100 under high temperature and high pressure, the average thickness td of the dielectric layer 111 may be 3 μm or more.
[0027] The first and second internal electrodes 121 and 122 are wound around the second direction as an axis, and the dielectric layer 111 can be disposed between the first and second internal electrodes 121 and 122.
[0028] The materials for forming the first and second internal electrodes 121 and 122 are not particularly limited and may include a conductive metal with excellent electrical conductivity. For example, the internal electrodes 121 and 122 can include one or more of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and their alloys.
[0029] On the other hand, the first and second internal electrodes 121 and 122 may contain the same conductive metal as each other, but are not limited thereto, and may contain different conductive metals from each other.
[0030] Also, the first internal electrode 121 can be in contact with the external electrode 131 at one end of the main body 110 in the second direction, and the second internal electrode 122 can be in contact with the external electrode 132 at the other end of the main body 110 in the second direction.
[0031] The external electrodes 131 and 132 are disposed on the third surface 3 and the fourth surface 4 of the main body 110 and are connected to the internal electrodes 121 and 122. Specifically, the first external electrode 131 is disposed on the third surface 3 and connected to the first internal electrode 121, and the second external electrode 132 is disposed on the fourth surface 4 and connected to the second internal electrode 122.
[0032] In this embodiment, the structure in which the capacitor component 100 has two external electrodes 131 and 132 is described. However, the number, shape, etc. of the external electrodes 131 and 132 can be changed according to the form of the internal electrodes 121 and 1220 and other purposes.
[0033] On the other hand, the external electrodes 131 and 132 may be formed of any material as long as it has electrical conductivity, such as metal, and a specific material may be determined in consideration of electrical characteristics, structural stability, etc.
[0034] The external electrodes 131 and 132 can be formed of a single layer or multiple layers, and can include an electrode layer that directly contacts the first and second surfaces 1 and 2 respectively and a plating layer disposed on the electrode layer, but are not limited thereto. A conductive resin layer including a thermosetting resin and a conductive metal may be disposed between the electrode layer and the plating layer.
[0035] A conventional multilayer ceramic capacitor forms a main body in a form in which dielectric layers and internal electrodes are alternately arranged and laminated. When a voltage is applied to the terminal electrodes of such a multilayer ceramic capacitor, shrinkage and expansion of the dielectric layer containing a piezoelectric substance occur, which applies stress to the entire multilayer ceramic capacitor.
[0036] On the other hand, when a multilayer ceramic capacitor is used in a high-voltage environment, the magnitude of the stress due to such an electrostriction phenomenon further increases, which may cause cracks to occur between the internal electrode and the dielectric layer with insufficient adhesive force.
[0037] The main body 110 of the capacitor component 100 according to an embodiment of the present invention can include a dielectric layer 111 and first and second internal electrodes 121 and 122 that are alternately arranged with the dielectric layer interposed therebetween and wound around the second direction as an axis.
[0038] Thereby, by minimizing the difference in the shrinkage behavior of the main body 110 in the first direction or the third direction, the phenomenon of cracks occurring in the capacitor component 100 can be suppressed.
[0039] On the other hand, a conventional wound capacitor forms a main body while winding a plurality of dielectric and internal electrode sheets, and thus can have a substantially cylindrical structure. Such a wound capacitor having a cylindrical structure has a small effective volume when mounted on a substrate or the like, and thus problems such as a decrease in reliability for ensuring an effective capacitance may occur.
[0040] Therefore, in one embodiment of the present invention, by further including a first surface 1 and a second surface 2 of the main body 110 that face each other in a first direction perpendicular to the second direction, and a fifth surface 5 and a sixth surface 6 that face each other in a third direction perpendicular to the first direction and the second direction, the effective volume is improved, which can be more advantageous in ensuring the effective capacitance.
[0041] FIG. 5 schematically shows a perspective view of an internal electrode and a sheet for forming a dielectric layer of a capacitor component 100 according to an embodiment.
[0042] The first sheet S1 in FIG. 5 can include a first dielectric green sheet 11 and a first internal electrode pattern 21 disposed on the first dielectric green sheet 11. The second sheet S2 can include a first dielectric green sheet 11 and a second internal electrode pattern 22 disposed on the first dielectric green sheet 11. At this time, the first internal electrode pattern 21 and the second internal electrode pattern 22 can be arranged so as to be offset in the second direction. The first dielectric green sheet 11 can become a dielectric layer 111 after firing, the first internal electrode pattern 21 can become a first internal electrode 121 after firing, and the second internal electrode pattern 22 can become a second internal electrode 122 after firing.
[0043] After the first sheet S1 and the second sheet S2 are laminated in the first direction, they can be wound around an axis in the second direction. The winding direction is not particularly limited as long as it is around an axis in the second direction.
[0044] On the other hand, in one embodiment of the present invention, the main body 110 can have a substantially hexahedral shape. The method of forming the main body 110 into a substantially hexahedral shape is not particularly limited. For example, when the first sheet S1 and the second sheet S2 are wound around an axis in the second direction, they can be wound using a quadrangular prism-shaped axis so as to form a hexahedral shape, or after forming a cylindrical wound body by winding the first sheet S1 and the second sheet S2 in a cylindrical shape, a method of processing using a hexahedral mold so as to form a hexahedral shape can be used.
[0045] Further, the second dielectric green sheet 12 may be disposed in a region where the first internal electrode pattern 21 is not disposed on the first dielectric green sheet 11 of the first sheet S1, and the second dielectric green sheet 12 may be disposed in a region where the second internal electrode pattern 22 is not disposed on the first dielectric green sheet 11 of the second sheet S2. Thereby, when the first sheet S1 and the second sheet S2 are wound around the second direction as an axis, it is possible to prevent displacement and steps between the sheets.
[0046] FIG. 6 schematically shows a perspective view of a process in which sheets forming an internal electrode and a dielectric layer are wound around a second direction in a capacitor component 100' according to an embodiment.
[0047] Referring to FIG. 6, the first sheet S1 and the second sheet S2 can be wound around the second direction to form a wound body. The wound body can become the main body 110 after crimping or firing.
[0048] In one embodiment, the first dielectric green sheet 11 included in the second sheet S2 may be longer in the third direction than the first dielectric green sheet 11, the first internal electrode pattern 21, and the second internal electrode pattern 22 included in the first sheet S1. Thereby, the end portion in the third direction of the first dielectric green sheet 11 included in the second sheet S2 can be formed as the protective layer 112 of the main body 110.
[0049] In one embodiment, the main body 110 may include a capacitance forming portion Ac in which capacitances are formed including regions where the first and second internal electrodes 121 and 122 are wound around the second direction as an axis, and a protective layer 112 disposed on the capacitance forming portion Ac.
[0050] The protective layer 112 can play a role of improving the mechanical strength and moisture resistance reliability of the capacitor component 100.
[0051] On the one hand, in order to ensure the moisture resistance reliability of the capacitor component 100, the protective layer 112 can cover the ends of the first and second internal electrodes 121 and 122.
[0052] The components of the protective layer 112 are not particularly limited, but can include components having excellent mechanical strength, moisture resistance reliability, and excellent insulation properties.
[0053] On the other hand, in the manufacturing process of the capacitor component 100, the dielectric layer 111 and the protective layer 112 can be integrally formed. That is, in one embodiment, the protective layer 112 can be in contact with the end of the dielectric layer 111. Also, the protective layer 112 can contain the same material as the dielectric material contained in the dielectric layer 111.
[0054] Referring to FIG. 7, the protective layer 112 can be formed to have a thickness greater than that of the dielectric layer 111. That is, in one embodiment, the average thickness tm of the protective layer 112 may be greater than the average thickness te of the dielectric layer 111. Thereby, the moisture resistance reliability of the capacitor component 100' can be further improved. The method of forming the average thickness tm of the protective layer 112 to be greater than the average thickness te of the dielectric layer 111 is not particularly limited, but as shown in FIG. 6, the first dielectric green sheet 11 included in the second sheet S2 is formed to be longer around the main body 110 than the first dielectric green sheet 11, the first internal electrode pattern 21, and the second internal electrode pattern 22 included in the first sheet S1. It can be formed by doing.
[0055] The method for measuring the average thickness tm of the protective layer 112 and the average thickness td of the dielectric layer 111 is not particularly limited. For example, the average thickness td of the dielectric layer 111 can be the average value of the widths in the third direction of the dielectric layer measured at the central points in the first and third directions of the capacitance forming portion Ac, two equally spaced points on the left side in the third direction with reference to the central points in the first and third directions of the capacitance forming portion Ac, and two equally spaced points on the right side in the third direction, in the cross-sections in the first and third directions polished up to the central portion in the second direction of the capacitor component 100. Also, the average thickness of the protective layer 112 can be the average value of the widths in the third direction of the protective layer measured at the central point in the first direction of the protective layer, two equally spaced points on the left side in the third direction with reference to the central point in the first direction of the protective layer, and two equally spaced points on the right side in the third direction, in the protective layer formed on the side surface in the third direction of the capacitance forming portion Ac. However, the average thickness tm of the protective layer 112 and the average thickness td of the dielectric layer 111 do not only mean the magnitudes of the widths in the third direction, but can also mean the thicknesses in the first direction.
[0056] FIG. 8 schematically shows a perspective view of a sheet for forming internal electrodes and a dielectric layer of a capacitor component 100'' according to an embodiment, and FIG. 9 shows a cross-section corresponding to the cross-section along line II-II' of FIG. 1 in the capacitor component 100'' according to an embodiment.
[0057] Referring to FIG. 8, the main body of the capacitor component 100'' according to an embodiment can be formed by laminating two or more layers of the first sheet S1 and the second sheet S2 respectively and winding them in the second direction. Thereby, the productivity of the capacitor component 100'' can be improved.
[0058] Referring to FIG. 8, by laminating two or more sheets of the first sheet S1 and the second sheet S2 respectively and winding them in the second direction, the main body 110 can include two or more layers of first internal electrodes 121 arranged spaced apart from each other in the first and third directions, and second internal electrodes 122 arranged spaced apart from each other in the first and third directions.
Description of Reference Numerals
[0059] 100, 100', 100'': Capacitor components 110: Body 111: Dielectric layer 112: Protective layer 121, 122: Internal electrodes
Claims
1. A main body including a dielectric layer and first and second internal electrodes that are alternately arranged with the dielectric layer therebetween and wound around an axis in a second direction, and external electrodes respectively disposed on a third surface and a fourth surface of the main body that face each other in the second direction. The main body further includes a first surface and a second surface that face each other in a first direction perpendicular to the second direction, and a fifth surface and a sixth surface that face each other in a third direction perpendicular to the first and second directions. A capacitor component.
2. The main body of the capacitor component according to claim 1, which is substantially hexahedral.
3. The capacitor component according to claim 1, wherein the dielectric layer contains Ba and Ti.
4. The capacitor component according to claim 1, wherein the first internal electrode is in contact with the external electrode at one end of the main body in the second direction, and the second internal electrode is in contact with the external electrode at the other end of the main body in the second direction.
5. The capacitor component according to claim 1, wherein the main body includes a capacitance forming portion in which a capacitance is formed including a region where the first and second internal electrodes are wound around an axis in the second direction, and a protective layer disposed on the capacitance forming portion.
6. The capacitor component according to claim 5, wherein an average thickness of the protective layer is greater than an average thickness of the dielectric layer.
7. The capacitor component according to claim 5, wherein the protective layer covers ends of the first and second internal electrodes.
8. The capacitor component according to claim 5, wherein the protective layer contains the same material as the dielectric material contained in the dielectric layer.
9. The capacitor component according to claim 5, wherein the protective layer is in contact with an end portion of the dielectric layer.
10. The capacitor component according to claim 1, wherein the first and second internal electrodes wound around an axis in the second direction are each one layer.
11. The capacitor component according to claim 1, wherein the main body includes two or more layers of first internal electrodes spaced apart from each other in the first and third directions, and two or more layers of second internal electrodes spaced apart from each other in the first and third directions.