Laminated type electronic component

Abstract

To provide a laminated type electronic component.SOLUTION: A laminated type electronic component includes a body including a dielectric layer, and an internal electrode alternately arranged with the dielectric layer, a solder layer which is arranged on the end of the internal electrode and contains a Zn-based solder, and an external electrode arranged on the solder layer, wherein the solder layer can include a first alloy layer which is arranged on the interface with the internal electrode and contains a Zn-Ni alloy, and a second alloy layer which is arranged on the interface with the external electrode and contains a Zn-Cu alloy.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a multilayer electronic component.

Background Art

[0002] A multilayer ceramic capacitor (MLCC), which is one type of multilayer electronic component, is a chip-shaped capacitor that is mounted on printed circuit boards of various electronic products such as video devices like liquid crystal displays (LCDs) and plasma display panels (PDPs), computers, smartphones, and mobile phones, and serves to charge or discharge electricity.

[0003] The multilayer ceramic capacitor has the advantages of being small in size while ensuring high capacitance and being easy to mount, so it can be used as a component of various electronic devices.

[0004] In recent years, with the miniaturization and high performance of electronic devices, multilayer ceramic capacitors also tend to be miniaturized and have higher capacitance. Due to such a trend, the importance of ensuring the high reliability of multilayer ceramic capacitors has been increasing.

[0005] Generally, a multilayer ceramic capacitor is formed by laminating and pressing ceramic green sheets printed with internal electrode patterns and then sintering them to form a body. In the sintering process, due to the difference in the shrinkage behavior between the internal electrode and the dielectric layer, the end portion of the internal electrode may be exposed while being disposed inside the body. In this case, there may be a problem that the connectivity between the internal electrode and the external electrode decreases.

Summary of the Invention

Problems to be Solved by the Invention

[0006] One of the various objects of the present invention is to provide a laminated electronic component with excellent reliability.

[0007] One of the various objects of the present invention is to improve the connectivity between the internal electrode and the external electrode.

[0008] 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

[0009] A laminated electronic component according to an embodiment of the present invention includes a main body including a dielectric layer and internal electrodes alternately arranged with the dielectric layer, a solder layer disposed at an end of the internal electrode and including a Zn-based solder, and an external electrode disposed on the solder layer. The solder layer may include a first alloy layer disposed at an interface with the internal electrode and containing a Zn-Ni alloy, and a second alloy layer disposed at an interface with the external electrode and containing a Zn-Cu alloy.

Effects of the Invention

[0010] As one of the various effects of the present invention, the reliability of the laminated electronic component can be improved.

[0011] As one of the various effects of the present invention, the contact property between the internal electrode and the external electrode can be improved.

[0012] However, the various and beneficial advantages and effects of the present invention are not limited to the above content, and can be more easily understood in the process of describing the specific embodiments of the present invention.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0014] Hereinafter, preferred embodiments of the present invention will be described with reference to 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 those having average knowledge in the relevant technical field. Therefore, for the sake of clearer explanation, the shapes and sizes of elements in the drawings may be enlarged or reduced (or emphasized or simplified).

[0015] Note that, for the purpose of clearly explaining the present invention, parts not related to the explanation in the drawings are omitted, the thickness is enlarged to clearly show various layers and regions, and components having the same function within the scope of the same concept are described using the same reference numerals. Further, throughout the specification, when a component is described as "including", it means that other components can be further included, rather than excluding other components, unless otherwise stated to the contrary.

[0016] In the drawings, the first direction can be defined as the stacking direction or the thickness (T) direction, the second direction as the length (L) direction, and the third direction as the width (W) direction.

[0017] Multilayer electronic component FIG. 1 schematically shows a perspective view of a multilayer electronic component according to an embodiment of the present invention. FIG. 2 schematically shows a cross-sectional view taken along line I-I' of FIG. 1. FIG. 3 schematically shows a cross-sectional view taken along line II-II' of FIG. 1. FIG. 4 schematically shows the body disassembled. FIG. 5 schematically shows a part of the body of FIG. 2. FIG. 6 is an enlarged view showing an enlarged K1 region of FIG. 2.

[0018] Hereinafter, with reference to FIGS. 1 to 6, a multilayer electronic component 100 according to an embodiment of the present invention will be described in detail. Further, as an example of the multilayer electronic component, a multilayer ceramic capacitor (hereinafter referred to as "MLCC") will be described, but the present invention is not limited thereto, and it is also applicable to various multilayer electronic components using a ceramic material, such as an inductor, a piezoelectric element, a varistor, or a thermistor.

[0019] A multilayer electronic component 100 according to an embodiment of the present invention includes a main body 110 including a dielectric layer 111 and internal electrodes 121 and 122 alternately arranged with the dielectric layer, solder layers 141 and 142 arranged at ends of the internal electrodes 121 and 122 and including a Zn-based solder, and external electrodes 131 and 132 arranged on the solder layers. The solder layer may include a first alloy layer 141a arranged at an interface with the internal electrode and containing a Zn-Ni alloy, and a second alloy layer 141c arranged at an interface with the external electrode and containing a Zn-Cu alloy.

[0020] The connectivity between the external electrode and the internal electrode has a great influence on the reliability of the multilayer electronic component. When the contact between the internal electrode and the external electrode deteriorates, the electrical connectivity between the internal electrode and the external electrode may deteriorate, and the equivalent series resistance (ESR) may increase, and there may be problems such as a decrease in moisture resistance reliability.

[0021] According to an embodiment of the present invention, solder layers 141 and 142 containing Zn-based solder are disposed at the ends of internal electrodes 121 and 122, and the solder layers include alloy layers 141a and 141c disposed at the interfaces with the internal electrodes and the external electrodes, thereby improving the electrical connectivity between the internal electrodes 121 and 122 and the external electrodes 131 and 132.

[0022] Hereinafter, each component included in the multilayer electronic component 100 according to an embodiment of the present invention will be described.

[0023] The main body 110 can have a dielectric layer 111 and internal electrodes 121 and 122 laminated alternately.

[0024] The specific shape of the main body 110 is not particularly limited, but as shown in the figure, the main body 110 can be formed 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 have a substantially hexahedron shape, although it does not have a hexahedron shape with perfect straight lines.

[0025] The main body 110 can have a first surface 1 and a second surface 2 facing each other in a first direction, a third surface 3 and a fourth surface 4 connected to the first surface 1 and the second surface 2 and facing each other in a second direction, and a fifth surface 5 and a sixth surface 6 connected to the first surface 1 and the second surface 2 and also connected to the third surface 3 and the fourth surface 4 and facing each other in a third direction.

[0026] A margin area where the internal electrodes 121 and 122 are not arranged overlaps on the dielectric layer 111, resulting in a step due to the thickness of the internal electrodes 121 and 122. The corner connecting the first surface and the third to fifth surfaces and / or the corner connecting the second surface and the third to fifth surfaces can have a form shrunk toward the center of the main body 110 in the first direction when based on the first surface or the second surface. Alternatively, due to the shrinkage behavior during the sintering process of the main body, the corner connecting the first surface 1 and the third to sixth surfaces 3, 4, 5, 6 and / or the corner connecting the second surface 2 and the third to sixth surfaces 3, 4, 5, 6 can have a form shrunk toward the center of the main body 110 in the first direction when based on the first surface or the second surface. Alternatively, in order to prevent chipping defects, etc., by performing a separate process to round the corners connecting the respective surfaces of the main body 110, the corners connecting the first surface and the third to sixth surfaces and / or the corners connecting the second surface and the third to sixth surfaces can have a round shape.

[0027] On the other hand, in order to suppress the step due to the internal electrodes 121 and 122, after cutting so that the internal electrodes are exposed on the fifth and sixth surfaces 5, 6 of the main body after lamination, when forming the margin portions 114 and 115 by laminating a single dielectric layer or two or more dielectric layers in the third direction (width direction) on both side surfaces of the capacitance forming portion Ac, the portions connecting the first surface and the fifth and sixth surfaces and the portions connecting the second surface and the fifth and sixth surfaces can not have a shrunk form.

[0028] The plurality of dielectric layers 111 forming the main body 110 are 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). The number of laminated dielectric layers does not particularly need to be limited and can be determined in consideration of the size of the laminated electronic component. For example, the main body can be formed by laminating 400 or more dielectric layers.

[0029] 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 prepare 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, barium titanate (BaTiO3)-based powder can be used. As a more specific example, the ceramic powder can be one or more of 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).

[0030] The average thickness td of the dielectric layer 111 does not particularly need to be limited. For example, it can be 0.01 μm to 10 μm. Also, the average thickness td of the dielectric layer 111 can be arbitrarily set according to the desired characteristics and applications. For example, in electronic components for small IT devices, in order to achieve miniaturization and high capacitance, the average thickness td of at least one of the plurality of dielectric layers 111 can be 0.4 μm or less.

[0031] Here, the average thickness td of the dielectric layer 111 may mean the size of the dielectric layer 111 in the first direction disposed between the internal electrodes 121 and 122. The average thickness of the dielectric layer 111 can be measured by scanning the cross-sections of the main body 110 in the first and second directions with a scanning electron microscope (SEM) at a magnification of 10,000 times. More specifically, the thickness can be measured at a number of points on one dielectric layer 111, for example, 30 points at equal intervals in the second direction, and the average value can be measured. The 30 equally spaced points can be specified by the capacitance forming portion Ac described later. Also, when such measurement of the average value is extended to 10 dielectric layers 111, the average thickness of the dielectric layer 111 can be more generalized.

[0032] The main body 110 includes a capacitance forming portion Ac in which a capacitance is formed, including a first internal electrode 121 and a second internal electrode 122 that are disposed inside the main body 110 and are disposed to face each other with the dielectric layer 111 interposed therebetween, and cover portions 112 and 113 formed on the upper and lower portions of the capacitance forming portion Ac in the first direction.

[0033] Also, the capacitance forming portion Ac is a portion that contributes to the formation of the capacitance of the capacitor, and can be formed by repeatedly laminating a plurality of first and second internal electrodes 121 and 122 with the dielectric layer 111 interposed therebetween.

[0034] The cover portions 112 and 113 can include an upper cover portion 112 disposed on the upper portion of the capacitance forming portion Ac in the first direction and a lower cover portion 113 disposed on the lower portion of the capacitance forming portion Ac in the first direction.

[0035] The upper cover portion 112 and the lower cover portion 113 can be formed by laminating a single dielectric layer or two or more dielectric layers in the thickness direction on the upper and lower surfaces of the capacitance forming portion Ac, and basically can play a role of preventing damage to the internal electrodes due to physical or chemical stress.

[0036] The upper cover portion 112 and the lower cover portion 113 may not include internal electrodes and may include the same material as the dielectric layer 111.

[0037] That is, the upper cover portion 112 and the lower cover portion 113 may include a ceramic material, for example, may include a barium titanate (BaTiO3)-based ceramic material.

[0038] On the other hand, the thicknesses of the cover portions 112 and 113 do not need to be particularly limited. However, in order to more easily achieve miniaturization and high capacitance of the multilayer electronic component, the thickness tc of the cover portions 112 and 113 can be 30 μm or less.

[0039] The average thickness tc of the cover portions 112 and 113 means the size in the first direction and can be a value obtained by averaging the sizes in the first direction of the cover portions 112 and 113 measured at five equally spaced points above or below the capacitance forming portion Ac.

[0040] In addition, margin portions 114 and 115 can be arranged on the side surfaces of the capacitance forming portion Ac.

[0041] The margin portions 114 and 115 can include a first margin portion 114 arranged on the fifth surface 5 of the main body 110 and a second margin portion 115 arranged on the sixth surface 6. That is, the margin portions 114 and 115 can be arranged on both end surfaces in the width direction of the ceramic main body 110.

[0042] As shown in FIG. 3, the margin portions 114 and 115 can mean the regions between the interfaces of both ends of the first and second internal electrodes 121 and 122 and the main body 110 in a cross-section obtained by cutting the main body 110 in the width-thickness (W-T) direction.

[0043] Basically, the margin portions 114 and 115 can play a role in preventing damage to the internal electrodes due to physical or chemical stress.

[0044] The margin portions 114 and 115 can be formed by applying a conductive paste to the ceramic green sheet except for the locations where the margin portions are to be formed to form internal electrodes.

[0045] Also, in order to suppress the step due to the internal electrodes 121 and 122, after cutting so that the internal electrodes are exposed on the fifth and sixth surfaces 5 and 6 of the main body after lamination, a single dielectric layer or two or more dielectric layers are laminated in the third direction (width direction) on both side surfaces of the capacitance forming portion Ac, whereby the margin portions 114 and 115 may be formed.

[0046] On the other hand, the width of the margin portions 114 and 115 does not particularly need to be limited. However, in order to more easily achieve miniaturization and high capacitance of the multilayer electronic component, the average width of the margin portions 114 and 115 can be 15 μm or less.

[0047] The average width of the margin portions 114 and 115 means the average size in the third direction of the region where the internal electrodes are separated from the fifth surface and the average size in the third direction of the region where the internal electrodes are separated from the sixth surface, and can be a value obtained by averaging the sizes in the third direction of the margin portions 114 and 115 measured at five equally spaced points on the side surface of the capacitance forming portion Ac.

[0048] Therefore, in one embodiment, the average size in the third direction of the regions where the internal electrodes 121 and 122 are separated from the fifth and sixth surfaces can be 15 μm or less, respectively.

[0049] On the other hand, when a magnetic material is applied to the main body 110 instead of the dielectric material, the multilayer electronic component can function as an inductor. The magnetic material can be, for example, ferrite and / or metal magnetic particles. When the multilayer electronic component functions as an inductor, the internal electrodes can be coil-type conductors.

[0050] Also, when a piezoelectric material is applied to the main body 110 instead of the dielectric material, the multilayer electronic component can function as a piezoelectric element. The piezoelectric material can be, for example, PZT (lead zirconate titanate).

[0051] Also, when a ZnO-based or SiC-based material is applied to the main body 110 instead of the dielectric material, the multilayer electronic component can function as a varistor, and when a spinel-based material is applied to the main body 110 instead of the dielectric material, the multilayer electronic component can function as a thermistor.

[0052] That is, the multilayer electronic component 100 according to an embodiment of the present invention can function not only as a multilayer ceramic capacitor but also as an inductor, a piezoelectric element, a varistor, or a thermistor by appropriately changing the material and structure of the main body 110.

[0053] The internal electrodes 121 and 122 can be alternately arranged with the dielectric layer 111. For example, the first internal electrode 121 and the second internal electrode 122, which are a pair of electrodes having different polarities from each other, can be arranged so as to face each other with the dielectric layer 111 interposed therebetween. The first internal electrode 121 and the second internal electrode 122 can be electrically separated from each other by the dielectric layer 111 disposed therebetween. At this time, the internal electrodes 121 and 122 can be alternately arranged with the dielectric layer 111 in the first direction.

[0054] The first internal electrode 121 can be separated from the fourth surface 4 and extend toward the third surface 3. The second internal electrode 122 can be separated from the third surface 3 and extend toward the fourth surface 4. The first internal electrode 121 can be electrically connected to the first external electrode 131 on the third surface 3 side, and the second internal electrode 122 can be electrically connected to the second external electrode 132 on the fourth surface 4 side.

[0055] The conductive metal contained in the internal electrodes 121 and 122 can be one or more of Ni, Cu, Pd, Ag, Au, Pt, Sn, W, Ti, and alloys thereof.

[0056] In one embodiment, the internal electrodes 121 and 122 can contain Ni. By the internal electrodes containing Ni, a Zn-Ni alloy can be easily formed at the interfaces with the solder layers 141 and 142. Also, the internal electrodes 121 and 122 can contain Ni as a main component. Here, containing as a main component can mean that when the cross-section of the internal electrode is analyzed by SEM-EDS, the ratio of the area occupied by Ni to the total area of the internal electrode is 90% or more.

[0057] The method for forming the internal electrodes 121 and 122 is not particularly limited. For example, the internal electrodes 121 and 122 can be formed by applying a conductive paste for internal electrodes containing a conductive metal onto a ceramic green sheet and firing it. As the method for applying the conductive paste for internal electrodes, a screen printing method or a gravure printing method can be used, but the present invention is not limited thereto.

[0058] The average thickness te of the internal electrodes 121 and 122 does not need to be particularly limited, but for example, it can be 0.01 μm to 3 μm. Also, the average thickness te of the internal electrodes 121 and 122 can be arbitrarily set according to the desired characteristics and applications. For example, in electronic components for small IT, in order to achieve miniaturization and high capacitance, the average thickness te of at least one of the plurality of internal electrodes 121 and 122 can be 0.4 μm or less.

[0059] Here, the average thickness te of the internal electrode can be measured by scanning the cross-sections of the main body 110 in the first direction and the second direction with a scanning electron microscope (SEM) at a magnification of 10,000 times. More specifically, the thickness can be measured at a number of points of one internal electrode 121 or 122, for example, 30 points at equal intervals in the second direction, and the average value can be measured. The 30 points at the above equal intervals can be specified in the capacitance forming portion Ac. Also, when such measurement of the average value is extended to 10 internal electrodes 121 and 122, the average thickness of the internal electrodes 121 and 122 can be more generalized.

[0060] The external electrodes 131 and 132 are disposed on the main body 110 and can be connected to the internal electrodes 121 and 122.

[0061] As shown in the form illustrated in FIG. 2, the first and second external electrodes 131 and 132 respectively disposed on the third and fourth surfaces 3 and 4 of the main body 110 and connected to the first and second internal electrodes 121 and 122 via the solder layers 141 and 142 can be included.

[0062] In the present embodiment, the structure in which the multilayer electronic component 100 has two external electrodes 131 and 132 is described. However, the number, shape, etc. of the external electrodes 131 and 132 can vary according to the form of the internal electrodes 121 and 122 and other purposes.

[0063] FIG. 6 is an enlarged view showing an enlarged view of the K1 region in FIG. 2. The K1 region shows an enlarged view of a part of the first external electrode 131, a part of the first solder layer 141, and a part of the first internal electrode 121. However, the first external electrode 131 is disposed on the third surface, and the second external electrode 132 is disposed on the fourth surface. Since the configurations of the first external electrode 131 and the second external electrode 132 are similar except for this difference, the following description will be based on the first external electrode 131, which is considered to include the description of the second external electrode 132. Also, the solder layers 141 and 142 and the internal electrodes 121 and 122 will be described based on the first solder layer 141 and the first internal electrode 121, which is considered to include the description of the second solder layer 142 and the second internal electrode 122.

[0064] The solder layers 141 and 142 are disposed at the ends of the internal electrodes 121 and 122 and can contain a Zn-based solder. The solder layers 141 and 142 can include a first alloy layer 141a disposed at the interface with the internal electrodes 121 and 122 and containing a Zn-Ni alloy, and a second alloy layer 141c disposed at the interface with the external electrodes 131 and 132 and containing a Zn-Cu alloy. Thereby, the connectivity between the internal electrodes 121 and 122 and the external electrodes 131 and 132 can be improved.

[0065] Since the Zn-based solder has a higher melting point than the Sn-based solder, it is classified as a high-temperature solder, and the melting point of the Zn-based solder can be about 300°C or higher and 400°C or lower. Thereby, during the heat treatment for forming the external electrodes, Zn can stably form an alloy with Ni and Cu, and the first and second alloy layers 141a and 141c can be easily formed.

[0066] In one embodiment, in the solder layer 141, when the region excluding the first and second alloy layers 141a and 141c is defined as the central region 141b, the Zn atomic percentage of the central region 141b can be higher than the Zn atomic percentages of the first and second alloy layers 141a and 141c.

[0067] On the other hand, the content of Zn in the central region 141b does not need to be particularly limited, but for example, it can be 80 wt% or more.

[0068] Also, the central region 141b can further contain one or more of Al and Cu. Al can play a role in increasing the spreading rate of the Zn-based solder, and Cu can play a role in increasing the melting point of the Zn-based solder.

[0069] The Zn-based solder can contain, for example, Zn, Al, and Cu. As a more specific example, the Zn-based solder can contain Zn: 80 to 90 wt%, Cu: 0.1 to 10 wt%, and Al: 0.1 to 10 wt%.

[0070] The first alloy layer 141a can be formed by the mutual diffusion of the internal electrode 121 and the solder layer 141, and the second alloy layer 141c can be formed by the mutual diffusion of the external electrode 131 and the solder layer 141.

[0071] Thereby, in one embodiment, the Zn atomic percentage of the first alloy layer 141a can decrease as it gets farther from the central region 141b. Also, the Ni atomic percentage of the first alloy layer 141a can increase as it gets farther from the central region 141b.

[0072] In one embodiment, the Zn atomic percentage of the second alloy layer 141c can decrease as it gets farther from the central region 141b. Also, the Cu atomic percentage of the second alloy layer 141c can increase as it gets farther from the central region 141b.

[0073] On the other hand, the analysis of the elements contained in the solder layers 141 and 142 can be measured by using a scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) on cross-sections in the first and second directions passing through the center in the third direction of the main body 110.

[0074] Also, at the end of the internal electrode 121, a line profile can be performed along the line up to the inside of the base electrode layer to analyze the change in the content of Zn, Ni, and Cu.

[0075] As a specific example, after scanning a cross-section obtained by cutting the multilayer electronic component 100 in the first and second directions at the center in the third direction with a scanning electron microscope (SEM) at a magnification of 20,000 to obtain an image, a line profile for Zn, Ni, and Cu can be performed. In the line profile graph obtained at this time, the portion where the content of Ni begins to decrease almost constantly is regarded as the boundary between the internal electrode 121 and the first alloy layer 141a, and from the boundary between the internal electrode and the first alloy layer, the portion where the content of Zn increases and then begins to converge to 80 wt% or more is regarded as the boundary between the first alloy layer 141a and the central region 141b, and from the boundary between the first alloy layer and the central region, the portion where the content of Zn converges to 80 wt% or more and then begins to decrease is regarded as the boundary between the central region 141b and the second alloy layer 141c, and from the boundary between the central region and the second alloy layer, the point where the content of Zn decreases to less than 5 wt% can be regarded as the boundary between the second alloy layer 141c and the external electrode 131.

[0076] In one embodiment, when the average thickness of the first alloy layer 141a is ti1 and the average thickness of the second alloy layer 141c is ti2, 1 μm ≤ ti1 ≤ 2 μm and 1 μm ≤ ti1 ≤ 2 μm can be satisfied. When ti1 and ti2 exceed 2 μm, there is a risk of radiation cracks due to excessive interdiffusion and volume expansion of the internal electrode. When it is less than 1 μm, there is a risk that the effect of improving the electrical connectivity between the internal electrodes 121 and 122 and the external electrodes 131 and 132 is not sufficient.

[0077] In one embodiment, when the average thickness of the external electrodes 131 and 132 is ta1 and the average thickness of the first alloy layer 141a is ti1, 0.02 ≤ ti1 / ta1 ≤ 0.1 can be satisfied.

[0078] When ti1 / ta1 is less than 0.02, there is a risk of reduced moisture resistance reliability. When it exceeds 0.1, there is a risk of short circuits or cracks occurring inside the main body.

[0079] The average thickness (ta1) of the external electrode, the average thickness (ti1) of the first alloy layer, and the average thickness (ti2) of the second alloy layer can be measured from an image obtained by scanning a cross-section of the main body 110 in the first and second directions with a scanning electron microscope (SEM). The average thickness (ta1) of the external electrode can be calculated from the value obtained by averaging the sizes in the second direction of the external electrode measured at five points having equal intervals in the first direction at the central part of the main body in the first direction.

[0080] The average thickness (ti1) of the first alloy layer and the average thickness (ti2) of the second alloy layer can be calculated by averaging the values measured by selecting five of the solder layers 141 arranged at the central part of the main body in the first direction. On the other hand, when it is difficult to distinguish between the first alloy layer 141a and the second alloy layer 141c and the central region 141b on the SEM image, a line profile is performed by SEM-EDS, and the thicknesses of the first alloy layer 141a and the second alloy layer 141c can be measured by measuring the length from the point where the atomic percentage of Zn starts to fall below 80 wt% to the point where it falls below 5 wt%.

[0081] In one embodiment, the main body 110 includes groove portions G1 and G2 in which the ends of the internal electrodes 121 and 122 are separated from one surface of the main body 110, and the solder layers 141 and 142 can include a first region disposed in the groove portions G1 and G2 and a second region protruding on one surface of the main body.

[0082] The groove portions G1 and G2 can be formed by the difference in the shrinkage behavior between the internal electrodes 121 and 122 and the dielectric layer 111 during the firing process of the main body 110. When the firing shrinkage rate of the internal electrodes 121 and 122 is larger than that of the dielectric layer 111, there may be a problem that the connectivity between the internal electrodes 121 and 122 and the external electrodes 131 and 132 is reduced due to the groove portions G1 and G2. Conventionally, in order to solve such a problem, a process of removing the protruding dielectric layer using a sandblasting method or the like has been added to try to solve such a problem. On the other hand, according to one embodiment of the present invention, since the solder layers 141 and 142 include a first region disposed in the groove portions G1 and G2 and a second region protruding on one surface of the main body, the connectivity between the internal electrodes 121 and 122 and the external electrodes 131 and 132 can be improved without a separate polishing process.

[0083] In one embodiment, in the cross section of the stacked electronic component 100 in the first and second directions, the second region can have a semi-circular shape. Thereby, the contact area with the external electrodes 131 and 132 can be maximized, and the electrical connectivity can be further improved.

[0084] In one embodiment, when the average thickness of the internal electrode is te, the average thickness of the dielectric layer is td, and the radius of the semi-circular shape is tr, te / 2 ≤ tr ≤ (te + td) / 2 can be satisfied. When the radius (tr) of the semi-circular shape is less than te / 2, the effect of improving the connectivity between the external electrode and the internal electrode is not sufficient, and when it exceeds (te + td) / 2, the solder layers 141 and 142 may be connected to form a single layer, and the bonding force between the external electrode and the main body may be weakened.

[0085] In one embodiment, the radius tr of the semi-circular shape can be 6 μm or less. When the radius tr of the semi-circular shape exceeds 6 μm, the adjacent solder layers 141 and 142 may be connected to form a single layer, and the bonding force between the external electrode and the main body may be weakened.

[0086] The radius tr of the semi-circular shape can be measured by scanning the cross-sections of the main body 110 in the first and second directions with a scanning electron microscope (SEM) at a magnification of 10,000 times. Also, the radius tr of the semi-circular shape can be measured at the electrode layers 141 and 142 of any five interfaces, and the average value can be taken as the radius tr of the semi-circular shape.

[0087] In one embodiment, there are a plurality of the internal electrodes 121 and 122, and the solder layers 141 and 142 disposed at one end of any one of the plurality of internal electrodes 121 and 122 can be arranged separately from the solder layers 141 and 142 disposed at the ends of the other internal electrodes. Thereby, the base electrode layers 131a and 132a are in contact with at least a part of the ends of the dielectric layer 111, and the bonding force between the external electrodes 131 and 132 and the main body 110 can be improved.

[0088] On the other hand, the method of forming the solder layers 141 and 142 does not particularly need to be limited. For example, after manufacturing the main body 110 through a sintering process, Zn-based solder is applied to the exposed surfaces of the internal electrodes 121 and 122 of the main body 110, and heat treatment is performed at about 300 °C for about 300 seconds, then the Zn-based solder can be melted and move to the ends of the internal electrodes. Thereafter, the multilayer electronic component 100 can be manufactured by forming the external electrodes 131 and 132.

[0089] The external electrodes 131 and 132 can be disposed on the main body 110.

[0090] As shown in the form illustrated in FIG. 2, the external electrodes 131 and 132 are respectively disposed on the third and fourth surfaces 3 and 4 of the main body 110, and can include first and second external electrodes 131 and 132 respectively connected to the first and second internal electrodes 121 and 122 via the solder layers 141 and 142.

[0091] In this embodiment, a structure in which the stacked electronic component 100 has two external electrodes 131 and 132 is described. However, the number, shape, etc. of the external electrodes 131 and 132 can vary according to the form of the internal electrodes 121 and 122 and other purposes.

[0092] 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 can be determined in consideration of electrical characteristics, structural stability, etc. Furthermore, it can have a multilayer structure.

[0093] For example, the external electrodes 131 and 132 can include electrode layers 131a and 132a disposed on the main body 110, and plating layers 131b and 132b formed on the electrode layers 131a and 132a.

[0094] In one embodiment, the external electrodes 131 and 132 can include electrode layers 131a and 132a that are disposed in contact with at least a part of the end portions of the dielectric layer 111 disposed between the internal electrodes 121 and 122 and cover the solder layers 141 and 142. Thereby, the bonding strength between the external electrodes 131 and 132 and the main body 110 can be improved, and the electrical connectivity between the internal electrodes 121 and 122 and the external electrodes 131 and 132 can be improved.

[0095] In one embodiment, the electrode layers 131a and 132a can include Cu and glass, and the internal electrodes 121 and 122 can include Ni. Since the solder layers 141 and 142 include Zn-based solder, the shape can be maintained even at the firing temperature, and the electrical connectivity between the internal electrodes 121 and 122 and the external electrodes 131 and 132 can be improved. Also, since the electrode layers 131a and 132a include Cu, the second alloy layer 141c can be easily formed, and since the internal electrodes 121 and 122 include Ni, the first alloy layer 141a can be easily formed.

[0096] In one embodiment, the electrode layers 131a and 132a may contain Cu and resin, and the internal electrodes 121 and 122 may contain Ni. By including Cu in the electrode layers 131a and 132a, the second alloy layer 141c can be easily formed, and by including Ni in the internal electrodes 121 and 122, the first alloy layer 141a can be easily formed.

[0097] Also, the electrode layers 131a and 132a can be in a form in which a fired electrode and a resin-based electrode are sequentially formed on the main body. Further, the electrode layers 131a and 132a may be formed by a method of transferring a sheet containing a conductive metal onto the main body, or may be formed by a method of transferring a sheet containing a conductive metal onto the fired electrode.

[0098] As the conductive metal contained in the electrode layers 131a and 132a, a material having excellent electrical conductivity can be used, but it is not particularly limited. For example, the conductive metal can be one or more of nickel (Ni), copper (Cu), and their alloys.

[0099] The plating layers 131b and 132b play a role in improving the mounting characteristics. The types of the plating layers 131b and 132b are not particularly limited, and can be plating layers containing one or more of Ni, Sn, Pd, and their alloys, and can be formed of a plurality of layers.

[0100] As a more specific example of the plating layers 131b and 132b, the plating layers 131b and 132b can be Ni plating layers or Sn plating layers, and may be in a form in which a Ni plating layer and an Sn plating layer are sequentially formed on the electrode layers 131a and 132a, or may be in a form in which an Sn plating layer, a Ni plating layer, and an Sn plating layer are sequentially formed. Further, the plating layers 131b and 132b may include a plurality of Ni plating layers and / or a plurality of Sn plating layers.

[0101] (Example) In order to confirm the effect of the ratio (ti1 / ta1) of the average thickness (ti1) of the first alloy layer to the average thickness (ta1) of the external electrode, sample chips of test numbers 1 to 6 were prepared, where the ratio (ti1 / ta1) of the average thickness (ti1) of the first alloy layer to the average thickness (ta1) of the external electrode satisfies the numerical values described in Table 1 below.

[0102] The capacitances of the sample chips of test numbers 1 to 6 were compared, and the moisture resistance reliability and the presence or absence of crack generation were evaluated and described in Table 1 below.

[0103] The capacitances were described as relative values with the capacitance of test number 5 as the reference value of 100%.

[0104] For the moisture resistance reliability, after preparing 40 sample chips for each test number, a voltage corresponding to 1.0 times the rated voltage was applied at a temperature of 85°C and a humidity of 85% for 100 hours. Then, sample chips with an insulation resistance lower than 10 kΩ were judged as defective, and the number of chips judged as defective was described.

[0105] The presence or absence of crack generation was confirmed by observing the cross-sections in the first and second directions cut at the center in the third direction of the sample chip.

[0106]

Table 1

[0107] For test numbers 3 to 5 that satisfy 0.02 ≦ ti1 / ta1 ≦ 0.1, they are excellent in capacitance and moisture resistance reliability, and no cracks occurred.

[0108] In contrast, it can be confirmed that test numbers 1 and 2 with ti1 / ta1 less than 0.02 are inferior in moisture resistance reliability.

[0109] Also, for test number 6 with ti1 / ta1 exceeding 0.1, cracks occurred inside the main body and a short circuit occurred.

[0110] As described above, the embodiments of the present invention have been explained in detail. However, the present invention is not limited by the above-described embodiments and the attached drawings, but is limited by the appended claims. Therefore, within the scope not departing from the technical idea of the present invention described in the claims, various forms of substitution, modification, and change are possible by those skilled in the art, and it can be said that these also belong to the scope of the present invention.

[0111] In addition, the expression "one embodiment" used in the present invention does not mean the same embodiment, but is provided to emphasize and explain each different unique feature. However, the above-presented one embodiment does not exclude the case where it is implemented in combination with the features of other embodiments. For example, even if a matter described in a specific one embodiment is not described in other embodiments, it can also be interpreted as an explanation related to other embodiments as long as there is no explanation contrary to that matter or no explanation conflicting with that matter in other embodiments.

[0112] The terms used in the present invention are only described for the purpose of explaining an example and are not intended to limit the present invention. At this time, the singular expression includes the plural unless the context clearly indicates a different meaning.

Description of Reference Numerals

[0113] 100 Multilayer electronic component 110 Body 111 Dielectric layer 112, 113 Cover portion 114, 115 Margin portion 121, 122 Internal electrode 131, 132 External electrode 131a, 132a Electrode layer 131b, 132b Plating layer 141, 142 Solder layer

Claims

1. A main body including a dielectric layer and internal electrodes alternately arranged with the dielectric layer, a solder layer disposed at an end of the internal electrode and including a Zn-based solder, and an external electrode disposed on the solder layer, wherein the solder layer includes a first alloy layer disposed at an interface with the internal electrode and containing a Zn—Ni alloy, and a second alloy layer disposed at an interface with the external electrode and containing a Zn—Cu alloy, the multilayer electronic component.

2. When a region excluding the first and second alloy layers in the solder layer is defined as a central region, a Zn atomic percentage in the central region is higher than Zn atomic percentages in the first and second alloy layers, the multilayer electronic component according to claim 1.

3. The Zn atomic percentage in the first alloy layer decreases as the distance from the central region increases, the multilayer electronic component according to claim 2.

4. The Zn atomic percentage in the second alloy layer decreases as the distance from the central region increases, the multilayer electronic component according to claim 2.

5. The central region further includes one or more of Al and Cu, the multilayer electronic component according to claim 2.

6. When an average thickness of the first alloy layer is ti1 and an average thickness of the second alloy layer is ti2, 1 μm ≤ ti1 ≤ 2 μm and 1 μm ≤ ti1 ≤ 2 μm are satisfied, the multilayer electronic component according to claim 1.

7. When an average thickness of the external electrode is ta1 and an average thickness of the first alloy layer is ti1, 0.02 ≤ ti1 / ta1 ≤ 0.1 is satisfied, the multilayer electronic component according to claim 1.

8. The external electrode includes a base electrode layer disposed to cover the solder layer in contact with at least a part of an end of a dielectric layer disposed between the internal electrodes, the multilayer electronic component according to claim 1.

9. The base electrode layer includes Cu and glass, and the internal electrode includes Ni, the multilayer electronic component according to claim 8.

10. The base electrode layer includes Cu and resin, and the internal electrode includes Ni, the multilayer electronic component according to claim 8.

11. The main body includes a groove portion in which an end of the internal electrode is spaced apart from one surface of the main body, and the solder layer includes a first region disposed in the groove portion and a second region protruding on one surface of the main body, the multilayer electronic component according to claim 1.

12. The internal electrodes are alternately arranged with the dielectric layers in the first direction, and the main body has a first surface and a second surface facing each other in the first direction, a third surface and a fourth surface connected to the first and second surfaces and facing each other in the second direction, and a fifth surface and a sixth surface connected to the first to fourth surfaces and facing each other in the third direction. The multilayer electronic component according to claim 11, wherein in a cross section of the multilayer electronic component in the first and second directions, the second region has a semicircular shape.

13. The multilayer electronic component according to claim 12, wherein when the average thickness of the internal electrode is te, the average thickness of the dielectric layer is td, and the radius of the semicircular shape is tr, te / 2 ≤ tr ≤ (te + td) / 2 is satisfied.

14. The multilayer electronic component according to claim 13, wherein when the radius of the semicircular shape is tr, tr is 6 μm or less.

15. The multilayer electronic component according to claim 13, wherein there are a plurality of the internal electrodes, and a solder layer disposed at an end of any one of the plurality of internal electrodes is disposed separately from a solder layer disposed at an end of another internal electrode.

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