Multilayer electronic components

Abstract

To prevent a hydrogen gas generated in a plating process from going into a chip to prevent the degradation of a dielectric layer in insulation resistance.SOLUTION: A laminate-type electronic component 100 comprises: a main body 110 including dielectric layers 111 and internal electrodes 121, 122; and external electrodes 131, 132 disposed on the main body 110 and connected to the internal electrodes 121, 122. The external electrodes 131, 132 include: first electrode layers 131a, 132a disposed on the main body 110 and containing Cu and glass; second electrode layers 131b, 132b disposed on the first electrode layers 131a, 132a and containing Ni and Cu; and third electrode layers 131c, 132c disposed on the second electrode layers 131b, 132b and containing Ni and glass.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Multi-layered ceramic capacitors (MLCCs), a type of multilayer electronic component, are chip-type capacitors that are mounted on printed circuit boards of various electronic products, such as visual devices like liquid crystal displays (LCDs) and plasma display panels (PDPs), computers, smartphones, and mobile phones, and serve to charge and discharge electricity.

[0003] Such multilayer ceramic capacitors can be used as components of various electronic devices due to their advantages of being small, having high capacitance, and being easy to mount. As various electronic devices such as computers and mobile devices become smaller and have higher output, there is an increasing demand for multilayer ceramic capacitors with smaller size and higher capacitance.

[0004] Furthermore, with the recent increase in interest in automotive electrical components in the industry, multilayer ceramic capacitors are also being used in automobiles or infotainment systems, and are therefore being required to have high reliability characteristics.

[0005] From the viewpoint of external electrodes, it is very important to achieve thin film that guarantees hermetic sealing and to improve moisture resistance that prevents the penetration of foreign matter, moisture, and gas into the chip interior.

[0006] If moisture resistance is not sufficiently ensured, the bonding strength between the internal electrodes and the dielectric layer will decrease, which can lead to problems such as an increased rate of short circuits, cracks, and deterioration of insulation resistance (IR).

[0007] One of the main causes of deterioration in moisture resistance is that hydrogen gas generated during the plating process may penetrate into the chip, which may cause deterioration in the insulation resistance of the dielectric layer when voltage is applied.

[0008] Therefore, a method for preventing hydrogen from entering the chip is required. Summary of the Invention [Problem to be solved by the invention]

[0009] One of several objects of the present invention is to provide a multilayer electronic component with improved reliability.

[0010] However, the object of the present invention is not limited to the above-mentioned contents, and will be more easily understood in the course of describing specific embodiments of the present invention. [Means for solving the problem]

[0011] A multilayer electronic component according to one embodiment of the present invention includes a body including a dielectric layer and an internal electrode, and external electrodes disposed on the body and connected to the internal electrode, the external electrodes including a first electrode layer disposed on the body and including Cu and glass, a second electrode layer disposed on the first electrode layer and including Ni and Cu, and a third electrode layer disposed on the second electrode layer and including Ni and glass. [Effects of the Invention]

[0012] One of the advantages of the present invention is that the reliability of the multilayer electronic component can be improved by having the external electrodes include a first electrode layer, a second electrode layer, and a third electrode layer, and the second electrode layer contains Cu and Ni.

[0013] However, the various advantageous and beneficial effects of the present invention are not limited to the above-mentioned contents, and will be more easily understood in the course of describing specific embodiments of the present invention. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic perspective view of a multilayer electronic component according to an embodiment of the present invention; [Figure 2] 2 is a schematic cross-sectional view taken along line II' of FIG. 1. [Figure 3] 2 is a schematic cross-sectional view taken along line II-II' in FIG. 1. [Figure 4] FIG. 2 is an exploded perspective view schematically showing the main body of FIG. 1 in an exploded state. [Figure 5] 1 is a graph showing peaks of Cu, Ni, and their alloys observed using micro X-ray diffraction. [Figure 6] 2 is a schematic cross-sectional view taken along line II' of a modified multilayer electronic component of FIG. 1. [Figure 7] 2 is a schematic cross-sectional view taken along line II' of another modified multilayer electronic component of FIG. 1. DETAILED DESCRIPTION OF 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 several other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Therefore, the shapes and sizes of elements in the drawings may be enlarged or reduced (or highlighted or simplified) for clearer explanation, and elements denoted by the same reference numerals in the drawings are the same elements.

[0016] In addition, in the drawings, parts not relevant to the description are omitted in order to clearly explain the present invention, and the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, so the present invention is not necessarily limited by the drawings. Furthermore, components having the same function within the same concept may be described using the same reference numerals. Furthermore, throughout the specification, when a part "comprises" a certain component, it does not mean that it excludes other components, but that it may further include other components, unless otherwise specified to the contrary.

[0017] In the drawings, the first direction can be defined as the thickness (T) direction, the second direction as the length (L) direction, and the third direction as the width (W) direction.

[0018] FIG. 1 is a schematic perspective view of a multilayer electronic component according to one embodiment of the present invention.

[0019] FIG. 2 is a schematic cross-sectional view taken along line II' of FIG.

[0020] FIG. 3 is a schematic cross-sectional view taken along line II-II' in FIG.

[0021] FIG. 4 is an exploded perspective view showing the main body of FIG. 1 in a disassembled state.

[0022] A multilayer electronic component 100 according to one embodiment of the present invention will be described in detail below with reference to FIGS.

[0023] A multilayer electronic component 100 according to one embodiment of the present invention includes a body 110 including a dielectric layer 111 and internal electrodes 121, 122, and external electrodes 131, 132 arranged on the body and connected to the internal electrodes, the external electrodes including first electrode layers 131a, 132a arranged on the body and including Cu and glass, second electrode layers 131b, 132b arranged on the first electrode layer and including Ni and Cu, and third electrode layers 131c, 132c arranged on the second electrode layer and including Ni and glass.

[0024] The body 110 is formed by alternately laminating dielectric layers 111 and internal electrodes 121 and 122 .

[0025] Although there is no particular limitation on the specific shape of the body 110, as shown in the figure, the body 110 may have a hexahedral shape or a similar shape. Due to shrinkage of the ceramic powder contained in the body 110 during the firing process, the body 110 may have a substantially hexahedral shape, although not a hexahedral shape with perfectly straight lines.

[0026] The main body 110 may have first and second surfaces 1 and 2 facing each other in a first direction, third and fourth surfaces 3 and 4 connected to the first and second surfaces 1 and 2 and facing each other in a second direction, and fifth and sixth surfaces 5 and 6 connected to the first and second surfaces 1 and 2, connected to the third and fourth surfaces 3 and 4, and facing each other in the third direction.

[0027] The plurality of dielectric layers 111 forming the body 110 are in a fired state, and the boundaries between adjacent dielectric layers 111 may be integrated to such an extent that they are difficult to identify without the use of a scanning electron microscope (SEM).

[0028] According to an embodiment of the present invention, the raw material for forming the dielectric layer 111 is not particularly limited as long as sufficient capacitance can be obtained. For example, a barium titanate-based material, a lead complex perovskite-based material, or a strontium titanate-based material can be used. The barium titanate-based material can include a BaTiO3-based ceramic powder, and examples of the ceramic powder include BaTiO3, BaTiO3 partially solid-dissolved with Ca (calcium), Zr (zirconium), etc. 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) or Ba(Ti 1-y Zr y )O3 (0 < y < 1), etc.

[0029] In addition, as raw materials for forming the dielectric layer 111, various ceramic additives, organic solvents, binders, dispersants, etc. can be added to powders such as barium titanate (BaTiO3) according to the purpose of the present invention.

[0030] On the other hand, the average thickness (td) of the dielectric layer 111 does not need to be particularly limited.

[0031] However, generally, when the dielectric layer is formed thin with a thickness less than 0.6 μm, especially when the thickness of the dielectric layer is 0.35 μm or less, there is a risk of reduced reliability.

[0032] According to an embodiment of the present invention, since the second electrode layers 131b and 132b contain Ni and Cu, it is possible to suppress the penetration of plating solution, moisture, hydrogen, etc. into the interior of the main body 110 and improve reliability. Therefore, even when the average thickness of the dielectric layer 111 is 0.35 μm or less, excellent reliability can be ensured.

[0033] Therefore, when the average thickness of the dielectric layer 111 is 0.35 μm or less, the reliability improvement effect according to the present invention can become more prominent.

[0034] The average thickness (td) of the dielectric layer 111 can mean the average thickness of the dielectric layer 111 disposed between the first and second internal electrodes 121 and 122.

[0035] The average thickness of the dielectric layer 111 can be measured by scanning an image of a cross section of the body 110 in the length and thickness direction (LT) using a scanning electron microscope (SEM) with a magnification of 10,000. More specifically, the thickness of one dielectric layer can be measured at 30 equally spaced points in the length direction in the scanned image, and an average value can be calculated. The 30 equally spaced points can be designated as the capacitance forming portion Ac. Furthermore, if this average measurement is extended to 10 dielectric layers and the average value is measured, the average thickness of the dielectric layer can be further generalized.

[0036] The main body 110 may include a capacitance forming portion Ac in which capacitance is formed, including a first internal electrode 121 and a second internal electrode 122 arranged inside the main body 110 and facing each other across a dielectric layer 111, and cover portions 112 and 113 formed at the top and bottom of the capacitance forming portion Ac in a first direction.

[0037] The capacitance forming portion Ac is a portion that contributes to forming 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 sandwiched therebetween.

[0038] The cover parts 112 and 113 may include an upper cover part 112 disposed above the capacitance forming part Ac in the first direction, and a lower cover part 113 disposed below the capacitance forming part Ac in the first direction.

[0039] The upper cover part 112 and the lower cover part 113 may 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 part Ac, respectively, and may basically serve to prevent damage to the internal electrodes due to physical or chemical stress.

[0040] The upper cover part 112 and the lower cover part 113 do not include an internal electrode and may include the same material as the dielectric layer 111 .

[0041] That is, the upper cover part 112 and the lower cover part 113 may include a ceramic material, for example, a barium titanate (BaTiO3) based ceramic material.

[0042] Meanwhile, the average thickness of the cover portions 112, 113 does not need to be particularly limited. However, in order to more easily achieve miniaturization and high capacity of the multilayer electronic component, the average thickness (tp) of the cover portions 112, 113 may be 15 μm or less. Furthermore, according to one embodiment of the present invention, the second electrode layers 131b, 132b contain Ni and Cu, which can prevent plating solution, moisture, hydrogen, etc. from penetrating into the body 110 and improve reliability. Therefore, even when the average thickness (tp) of the cover portions 112, 113 is 15 μm or less, excellent reliability can be ensured.

[0043] The average thickness (tp) of the cover parts 112, 113 may refer to the size in the first direction, and may be the average value of the size in the first direction of the cover parts 112, 113 measured at five equally spaced points on the top or bottom of the capacitance forming part Ac.

[0044] Additionally, margin portions 114 and 115 may be arranged on the side surfaces of the capacitance forming portion Ac.

[0045] The margin portions 114, 115 may include a margin portion 114 disposed on the fifth surface 5 of the body 110 and a margin portion 115 disposed on the sixth surface 6. That is, the margin portions 114, 115 may be disposed on both end surfaces of the ceramic body 110 in the width direction.

[0046] The margin portions 114 and 115 may refer to the regions between both ends of the first and second internal electrodes 121 and 122 and the boundary surface of the body 110 in a cross-section of the body 110 cut in the width-thickness (WT) direction, as shown in FIG. 3.

[0047] The margin portions 114 and 115 basically serve to prevent damage to the internal electrodes due to physical or chemical stress.

[0048] The margin portions 114 and 115 can be formed by applying a conductive paste to the ceramic green sheet except for the areas where the margin portions are to be formed, thereby forming internal electrodes.

[0049] In addition, in order to suppress the steps caused by the internal electrodes 121, 122, after lamination, the internal electrodes can be cut so that they are exposed on the fifth and sixth surfaces 5, 6 of the main body, and then a single dielectric layer or two or more dielectric layers can be laminated in the third direction (width direction) on both side surfaces of the capacitance forming portion Ac to form margin portions 114, 115.

[0050] Meanwhile, the width of the margin portions 114, 115 does not need to be particularly limited. However, in order to more easily achieve miniaturization and high capacity of the multilayer electronic component, the average width of the margin portions 114, 115 may be 15 μm or less. Furthermore, according to one embodiment of the present invention, the second electrode layers 131b, 132b contain Ni and Cu, which can prevent the penetration of plating solution, moisture, hydrogen, etc. into the main body 110 and improve reliability. Therefore, even when the average width of the margin portions 114, 115 is 15 μm or less, excellent reliability can be ensured.

[0051] The average width of the margin portions 114, 115 may refer to the average size of the margin portions 114, 115 in the third direction, and may be the average value of the size of the margin portions 114, 115 in the third direction measured at five equally spaced points on the side of the capacitance forming portion Ac.

[0052] The internal electrodes 121 and 122 may be stacked alternately with the dielectric layers 111 .

[0053] The internal electrodes 121, 122 may include first and second internal electrodes 121, 122. The first and second internal electrodes 121, 122 are alternately arranged to face each other across the dielectric layer 111 constituting the body 110, and may be exposed to the third and fourth surfaces 3, 4 of the body 110, respectively.

[0054] The first internal electrode 121 may be spaced apart from the fourth surface 4 and exposed through the third surface 3, and the second internal electrode 122 may be spaced apart from the third surface 3 and exposed through the fourth surface 4. A first external electrode 131 may be disposed on the third surface 3 of the body and connected to the first internal electrode 121, and a second external electrode 132 may be disposed on the fourth surface 4 of the body and connected to the second internal electrode 122.

[0055] That is, the first internal electrode 121 is connected to the first external electrode 131 but not to the second external electrode 132, and the second internal electrode 122 is connected to the second external electrode 132 but not to the first external electrode 131. Therefore, the first internal electrodes 121 may be formed at a predetermined distance apart on the fourth surface 4, and the second internal electrodes 122 may be formed at a predetermined distance apart on the third surface 3.

[0056] At this time, the first and second internal electrodes 121 and 122 can be electrically isolated from each other by the dielectric layer 111 disposed therebetween.

[0057] The body 110 may be formed by alternately stacking ceramic green sheets on which the first internal electrodes 121 are printed and ceramic green sheets on which the second internal electrodes 122 are printed, and then firing the stacked sheets.

[0058] There are no particular limitations on the material forming the internal electrodes 121 and 122, and any material with excellent electrical conductivity can be used. 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 alloys thereof.

[0059] The internal electrodes 121 and 122 may be formed by printing a conductive paste for internal electrodes, including at least one of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), and alloys thereof, on the ceramic green sheets. The method for printing the conductive paste for internal electrodes may be screen printing or gravure printing, but the present invention is not limited thereto.

[0060] On the other hand, the average thickness (te) of the internal electrodes 121, 122 does not need to be particularly limited.

[0061] However, when the internal electrodes are generally formed to a thickness of less than 0.6 μm, and particularly when the thickness of the internal electrodes is 0.35 μm or less, there is a risk of the reliability decreasing.

[0062] According to one embodiment of the present invention, the second electrode layers 131b, 132b contain Ni and Cu, which can prevent plating solution, moisture, hydrogen, etc. from penetrating into the main body 110, thereby improving reliability. Therefore, excellent reliability can be ensured even when the average thickness of the internal electrodes 121, 122 is 0.35 μm or less.

[0063] Therefore, when the internal electrodes 121, 122 have an average thickness of 0.35 μm or less, the effect of the present invention is more pronounced, and miniaturization and high capacity of the ceramic electronic component can be more easily achieved.

[0064] The average thickness (te) of the internal electrodes 121 and 122 may refer to the average thickness of the internal electrodes 121 and 122.

[0065] The average thickness of the internal electrodes 121, 122 can be measured by scanning an image of a cross section of the body 110 in the length and thickness direction (LT) using a scanning electron microscope (SEM) with a magnification of 10,000. More specifically, in the scanned image, the thickness of one internal electrode can be measured at 30 equally spaced points in the length direction, and an average value can be calculated. The 30 equally spaced points can be designated as the capacitance forming portion Ac. Furthermore, if this average value measurement is extended to zero internal electrodes, the average thickness of the internal electrodes can be further generalized.

[0066] The external electrodes 131 and 132 may be disposed on the third surface 3 and the fourth surface 4 of the body 110. The external electrodes 131 and 132 may include first and second external electrodes 131 and 132 disposed on the third and fourth surfaces 3 and 4 of the body 110, respectively, and connected to the first and second internal electrodes 121 and 122, respectively.

[0067] In this embodiment, the multilayer electronic component 100 has a structure having two external electrodes 131 and 132, but the number and shape of the external electrodes 131 and 132 can be changed depending on the shape of the internal electrodes 121 and 122 and other purposes.

[0068] The external electrodes 131, 132 may include a first electrode layer 131a, 132a disposed on the main body 110 and including Cu and glass, a second electrode layer 131b, 132b disposed on the first electrode layer and including Ni and Cu, and a third electrode layer 131c, 132c disposed on the second electrode layer and including Ni and glass.

[0069] Previously, the external electrode was a fired electrode containing Cu and glass, and the Cu of the external electrode diffused into the Ni of the internal electrode during the firing process in the area where the internal and external electrodes met, forming a Cu-Ni alloy to ensure electrical connectivity and suppress the penetration of plating liquid and hydrogen, ensuring moisture resistance reliability.

[0070] However, it is difficult for a Cu-Ni alloy to form outside the area where the internal and external electrodes meet, which can result in insufficient hydrogen penetration suppression. Furthermore, if the Cu from the external electrode diffuses excessively into the internal electrode, problems such as radial cracks may occur due to the difference in diffusion coefficients between the two metals and the increased stress caused by Cu diffusion.

[0071] According to the present invention, the second electrode layers 131b, 132b arranged on the first electrode layers 131a, 132a contain Ni and Cu, which more reliably prevents plating solution, moisture, hydrogen, etc. from penetrating into the main body 110, and also prevents problems such as radial cracks that occur in the conventional technology.

[0072] Since the first electrode layers 131a and 132a contain Cu and the third electrode layer contains Ni, the Cu in the first electrode layers 131a and 132a diffuses into the third electrode layers 131c and 132c during the firing process to form the external electrodes, thereby forming second electrode layers 131b and 132b containing Cu and Ni. The method for achieving the structure of the external electrodes 131 and 132 of the present invention is not particularly limited. For example, the structure of the external electrodes 131 and 132 of the present invention can be achieved by applying a paste containing Cu and glass to the main body 110, followed by applying a paste containing Ni and glass, followed by firing. The firing conditions are not particularly limited, but as a preferred example, the second electrode layers 131b and 132b can be formed by heat treatment at a temperature of 700°C or higher for at least one hour.

[0073] When the first electrode layers 131a and 132a contain Cu and the third electrode layers 131c and 132c contain Ni, it may be easier to form the second electrode layers 131b and 132b than when the first electrode layers 131a and 132a contain Ni and the third electrode layers 131c and 132c contain Cu. This is because Cu and Ni have different reaction rates, and diffusion generally occurs from Cu to Ni during alloy formation to form the alloy.

[0074] The second electrode layers 131b and 132b can act as a barrier to prevent the penetration of plating solution, moisture, hydrogen, etc. In particular, they can essentially block hydrogen, which causes deterioration of insulation resistance (IR), from penetrating outside the first electrode layers 131c and 132c, thereby significantly improving high-temperature insulation resistance. Furthermore, even if some unplated areas occur on the external electrodes 131 and 132, they can prevent solder from penetrating into the first electrode layers 131a and 132a, thereby ensuring the effect of a protective film that protects the body 110 and the first electrode layers 131a and 132a from external thermal and chemical shocks.

[0075] In one embodiment, the average thickness of the second electrode layers 131b and 132b may be 1 μm or more and 10 μm or less.

[0076] If the average thickness of the second electrode layers 131b, 132b is less than 1 μm, the second electrode layers may be cut, resulting in low coverage of the first electrode layers 131a, 132a, and the effect of suppressing the penetration of plating liquid, moisture, hydrogen, etc. may be insufficient.

[0077] On the other hand, if the average thickness of the second electrode layers 131b, 132b exceeds 10 μm, the thickness of the external electrodes may become too thick, which may reduce the capacitance per unit volume, and the stress on the chip may increase, which may reduce the bending strength and increase the equivalent series resistance (ESR).

[0078] The average thickness of the second electrode layers 131b, 132b can be measured by observing a cross section cut in the first and second directions from the center in the third direction, and can be the average value of the thicknesses of the second electrode layers 131b, 132b measured at five equally spaced points arranged on the capacitance forming portion Ac in the second direction.

[0079] In one embodiment, the sum of the number of moles of Ni atoms and Cu atoms relative to the total number of moles of atoms constituting the second electrode layers 131b and 132b may be 0.95 or more, i.e., the second electrode layers 131b and 132b may be substantially composed of Cu and Ni, excluding elements detected as impurities.

[0080] In this case, the components of the second electrode layers 131b and 132b may be calculated from images observed using SEM-EDS (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy). Specifically, the multilayer electronic component is polished up to the center in the width direction (third direction) to expose a cross section in the length direction and thickness direction (LT cross section). Then, the second electrode layer is divided into five equal regions in the thickness direction, and the central region among these regions is subjected to EDS to measure the number of moles of each element contained in the second electrode layer.

[0081] In one embodiment, the second electrode layers 131b and 132b may include a Cu—Ni alloy, that is, the Cu and Ni included in the second electrode layers may be in the form of a Cu—Ni alloy.

[0082] Cu-Ni alloys are not only corrosion resistant to plating solutions but also have the property of being difficult for hydrogen to permeate, which can further improve the effect of suppressing hydrogen permeation in plating solutions according to the present invention.

[0083] At this time, the Cu-Ni alloy contained in the second electrode layers 131b and 132b is Cu 0.3 Ni 0.7 , Cu 0.5 Ni 0.5 , Cu 0.7 Ni 0.3 and Cu 0.9 Ni 0.1 It can be one or more of:

[0084] FIG. 5 is a graph showing the peaks of Cu, Ni, and their alloys observed using micro X-ray diffraction.0.3 Ni 0.7 , Cu 0.5 Ni 0.5 , Cu 0.7 Ni 0.3 and Cu 0.9 Ni 0.1 It can be seen that the maximum peak of appears between the maximum peak of Cu (L1) and the maximum peak of Ni (L2).

[0085] Therefore, the second electrode layers 131b and 132b are Cu 0.3 Ni 0.7 , Cu 0.5 Ni 0.5 , Cu 0.7 Ni 0.3 and Cu 0.9 Ni 0.1 By including one or more of these, when analyzed by XRD, the maximum peak of the second electrode layers 131b and 132b can be located between the maximum peak of Cu and the maximum peak of Ni.

[0086] In one embodiment, an alloy containing Cu and Ni may be disposed in a region where the first electrode layers 131a, 132a contact the internal electrodes 121, 122. Cu contained in the first electrode layers 131a, 132a may diffuse into the internal electrodes to form an alloy containing Cu and Ni in the region where the first electrode layers 131a, 132a contact the internal electrodes, thereby further improving reliability.

[0087] In one embodiment, when observing the cross sections of the multilayer electronic component 100 in the second and third directions, where E1 is the overall length of the first electrode layer at the boundary between the first electrode layer 131a, 132a and the second electrode layer 131b, 132b and E2 is the overall length of the second electrode layer, the average value of E2 / E1 may be 0.9 or greater. If E1 and E2 have the same value, it can be considered that the second electrode layer completely covers the first electrode layer. If E2 is smaller than E1, it can be considered that the second electrode layer does not partially cover the first electrode layer. If the average value of E2 / E1 is less than 0.9, the second electrode layer may not be able to sufficiently suppress the penetration of plating solution, moisture, hydrogen, etc.

[0088] In this case, the average value of E2 / E1 may be the average value of E2 / E1 values ​​measured at a cross section (LT cross section) cut in the first and second directions at five points equally spaced in the third direction on the body 110.

[0089] In one embodiment, the average thickness of the third electrode layers 131c, 132c may be thicker than the average thickness of the first electrode layers 131a, 132a. Because the diffusion coefficient of Cu contained in the first electrode layers 131a, 132a is greater than the diffusion coefficient of Ni contained in the third electrode layers 131c, 132c, if the third electrode layers 131c, 132c are thicker than the first electrode layers 131a, 132a, the second electrode layers 131b, 132b can be more easily realized. More preferably, the average thickness of the third electrode layers 131c, 132c may be 1.1 to 1.5 times the average thickness of the first electrode layers 131a, 132a. If the average thickness of the third electrode layers 131c, 132c is less than 1.1 times the average thickness of the first electrode layers 131a, 132a, the effect of easily forming the second electrode layers 131b, 132b may be insufficient, and if it exceeds 1.5 times, the capacitance per unit volume may decrease or the ESR may increase.

[0090] As a specific example, the average thickness of the first electrode layers 131a and 132a may be 6 to 10 μm, and the thickness of the third electrode layers 131c and 132c may be determined within a range of 1.1 to 1.5 times the average thickness of the first electrode layers 131a and 132a.

[0091] The average thickness of the first electrode layers 131a, 132a and the average thickness of the third electrode layers 131c, 132c can be measured by observing cross sections cut in the first and second directions from the center in the third direction, and can be the average values ​​of the thicknesses of the first electrode layers 131a, 132a and the third electrode layers 131c, 132c measured at five equally spaced points arranged on the capacitance forming portion Ac in the second direction.

[0092] Fig. 6 is a schematic cross-sectional view taken along line II' of a multilayer electronic component according to a modified example of Fig. 1. Referring to Fig. 6, the multilayer electronic component may further include plating layers 131d and 132d disposed on the third electrode layers 131c and 132c.

[0093] The plating layers 131d and 132d serve to improve mounting characteristics. The type of the plating layers 131d and 132d is not particularly limited, and may be a plating layer containing one or more of Ni, Sn, Pd, and alloys thereof, and may be formed of a plurality of layers.

[0094] As a specific example, the plating layers 131d and 132d may be Sn plating layers. Conventionally, plating layers have a two-layer structure in which a Sn plating layer is disposed on a Ni plating layer. According to the present invention, since the third electrode layer contains Ni, sufficient mountability can be ensured even when only a Sn plating layer is disposed, and since the second electrode layer can act as a barrier, solder can be prevented from penetrating into the first electrode layer.

[0095] However, it is not necessary to be limited to a structure in which only a Sn plating layer is arranged, and as shown in FIG. 7, the plating layer may also include Ni plating layers 131d1, 132d1 arranged on the third electrode layer and Sn plating layers 131d2, 132d2 arranged on the Ni plating layers.

[0096] The size of the multilayer electronic component 100 does not need to be particularly limited.

[0097] However, in order to simultaneously achieve miniaturization and high capacity, it is necessary to reduce the thickness of the dielectric layers and internal electrodes and increase the number of layers. Therefore, the effect of improving reliability and insulation resistance according to the present invention can be more pronounced in a multilayer electronic component 100 having a size of 1005 (length x width, 1.0 mm x 0.5 mm) or less.

[0098] Therefore, taking into consideration manufacturing errors, the size of the external electrodes, etc., the reliability improvement effect of the present invention can be more significant when the length of the multilayer electronic component 100 is 1.1 mm or less and the width is 0.55 mm or less. Here, the length of the multilayer electronic component 100 may refer to the maximum size of the multilayer electronic component 100 in the second direction, and the width of the multilayer electronic component 100 may refer to the maximum size of the multilayer electronic component 100 in the third direction.

[0099] (Experimental Example 1) Table 1 below shows the insulation resistance characteristics, solder bath test, and ESR measured and evaluated while changing the thickness of the second electrode layer.

[0100] The average thickness of the second electrode layer was measured by observing a cross section cut in the first and second directions from the center in the third direction, as described above, and was the average value of thicknesses of the second electrode layer measured at five equally spaced points arranged on the capacitance forming part Ac in the second direction. Furthermore, when analyzed by XRD, it was confirmed that the maximum peak of the second electrode layer appeared between the maximum peak of Cu and the maximum peak of Ni, confirming that the second electrode layer contained a Cu-Ni alloy.

[0101] For the insulation resistance characteristics, 20 sample chips were prepared for each test number, and a voltage of 4V was applied for 12 hours at a temperature of 85°C and a relative humidity of 85%. Samples whose insulation resistance value fell to 1 / 10 or less of the initial value were judged as NG, and the [number of samples judged as NG / total number of samples] was recorded.

[0102] For the solder bath test, 200 sample chips were prepared for each test number, then transferred to a board with heat-resistant tape attached, and then immersed in flux to clean. After that, the board was completely immersed in the solder bath to wet the lead, and if the de-wetting area on the head surface of the electrode fell into one of the following i), ii) or iii), it was judged as NG, and the [number of samples judged as NG / total number of samples] was recorded. i) When the dewetting area exceeds 20% of the total area of ​​the head surface of the external electrode ii) When the dewetting area is ceramic or Cu exposure is 10% or more of the total area iii) If the de-wetting area is an edge part, it is 1 / 2 (50%) or more of the de-wet area.

[0103] For bending strength, 30 sample chips were prepared for each test number, and the chips were mounted on a bending strength test board. Using strength testing equipment (Tira), a force was applied to the PCB to bend it up to 6mm at a speed of 0.5mm / s. Samples whose chips were broken were judged as NG, and the [number of samples judged as NG / total number of samples] was recorded.

[0104] For ESR, 400 sample chips per test number are prepared, then mounted on an ESR board, and a 260° reflow is carried out. After inputting the ESR frequency that matches the chip design using automated equipment, measurements are taken and samples that do not meet the SPEC (mΩ) according to the chip capacitance are judged as NG, and the [number of samples judged as NG / total number of samples] is recorded.

[0105] [Table 1] *:Comparative example

[0106] In the case of Test No. 1, since the average thickness of the second electrode layer is thin, less than 1 μm, it can be seen that the evaluation results of the insulation resistance characteristics and the solder bath test are poor.

[0107] In the case of test number 5, it can be seen that the average thickness of the second electrode layer is thick, exceeding 10 μm, and therefore the bending strength and ESR evaluation results are poor.

[0108] On the other hand, in the case of test numbers 2 to 4 in which the average thickness of the second electrode layer is 1 μm or more and 10 μm or less, it can be confirmed that the evaluation results of the insulation resistance characteristics, solder bath test, bending strength and ESR are all excellent.

[0109] (Experimental Example 2) An experiment was conducted to compare the hydrogen permeation prevention effect between a conventional example in which the external electrode was made of only a fired electrode containing Cu and glass and an example of the present invention having the external electrode structure according to the present invention.

[0110] The measurement conditions were as follows: Wait Time: 5 seconds, Integration Time: 75 seconds, Comparator Level: 0.1%, Comparator Wait Time: 40 seconds, using a Horiba Hydrogen analyzer.

[0111] The conventional sample chips were loaded into a hydrogen analyzer so that the total weight was 1g, and the temperature was rapidly raised to 2000℃ or higher to quantitatively analyze the detected hydrogen. In the case of the invention, quantitative analysis of the detected hydrogen was also carried out under the same conditions, and the results are shown in Table 2 below.

[0112] [Table 2]

[0113] In the case of the inventive example, the total amount of detected hydrogen was 2.89 ppm, significantly lower than the conventional example. This means that in the inventive example, the amount of residual hydrogen in the plated tip was significantly lower than in the conventional example due to the hydrogen permeation prevention effect of the alloy layer, confirming the hydrogen permeation prevention effect of the inventive example.

[0114] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and the accompanying drawings, but is limited by the scope of the accompanying claims. Therefore, various substitutions, modifications, and changes may be made by a person skilled in the art without departing from the technical spirit of the present invention as set forth in the claims, and these also fall within the scope of the present invention. [Explanation of symbols]

[0115] 100: Multilayer electronic components 110:Main body 121, 122: Internal electrode 111: Dielectric layer 112, 113: Cover part 131, 132: External electrode 131a, 132a: first electrode layer 131b, 132b: Second electrode layer 131c, 132c: Third electrode layer

Claims

1. a body including a dielectric layer and an internal electrode; an outer electrode disposed on the body and connected to the inner electrode; The external electrode is a first electrode layer disposed on the body, the first electrode layer comprising Cu and glass; a second electrode layer disposed on the first electrode layer and including Ni and Cu; and a third electrode layer disposed on the second electrode layer and including Ni and glass; Multilayer electronic components.

2. 2. The multilayer electronic component according to claim 1, wherein the average thickness of the second electrode layer is 1 μm or more and 10 μm or less.

3. 2. The multilayer electronic component according to claim 1, wherein the sum of the number of moles of Ni atoms and Cu atoms relative to the total number of moles of atoms constituting said second electrode layer is 0.95 or more.

4. 2. The multilayer electronic component according to claim 1, wherein the second electrode layer includes a Cu—Ni alloy.

5. The Cu—Ni alloy is Cu ０．３ Ni ０．７ , Cu ０．５ Ni ０．５ , Cu ０．７ Ni ０．３ and Cu ０．９ Ni ０．１ The multilayer electronic component according to claim 4, wherein the multilayer electronic component is one or more of the following:

6. 5. The multilayer electronic component according to claim 4, wherein the second electrode layer has a maximum peak between the maximum peak of Cu and the maximum peak of Ni when analyzed by XRD.

7. 2. The multilayer electronic component according to claim 1, wherein the second electrode layer is made substantially of a Cu--Ni alloy.

8. 2. The multilayer electronic component according to claim 1, wherein an alloy containing Cu and Ni is disposed in a region where the first electrode layer and the internal electrode contact each other.

9. In the cross sections of the multilayer electronic component in the second and third directions, 2. The multilayer electronic component according to claim 1, wherein, when an overall length of the first electrode layer at the boundary between the first electrode layer and the second electrode layer is E1 and an overall length of the second electrode layer is E2, an average value of E2 / E1 is 0.9 or more.

10. The multilayer electronic component according to claim 1 , further comprising a plating layer disposed on the third electrode layer.

11. The multilayer electronic component according to claim 10 , wherein the plating layer is a Sn plating layer.

12. The multilayer electronic component according to claim 10 , wherein the plating layer includes a Ni plating layer disposed on the third electrode layer and a Sn plating layer disposed on the Ni plating layer.

13. 2. The multilayer electronic component according to claim 1, wherein an average thickness of said third electrode layer is greater than an average thickness of said first electrode layer.

14. 14. The multilayer electronic component according to claim 13, wherein the average thickness of the third electrode layer is 1.1 times or more and 1.5 times or less the average thickness of the first electrode layer.

15. 2. The multilayer electronic component according to claim 1, wherein the internal electrodes have an average thickness of 0.35 [mu]m or less.

16. 2. The multilayer electronic component according to claim 1, wherein the dielectric layers have an average thickness of 0.35 μm or less.

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