CN114639545A - Multilayer capacitor and board having the same mounted thereon - Google Patents

Abstract

The present disclosure provides a multilayer capacitor and a board having the same mounted thereon. The multilayer capacitor includes: a capacitor body including a first dielectric layer, a second dielectric layer, and an internal electrode stacked; and first and second external electrodes. The internal electrodes include a first internal electrode, a second internal electrode, a first floating electrode, a second floating electrode and a third floating electrode, the first floating electrode is arranged on the first dielectric layer and positioned between the first internal electrode and the second internal electrode, and the second floating electrode and the third floating electrode are arranged on the second dielectric layer. The second floating electrode overlaps with a portion of the first internal electrode and overlaps with a portion of the first floating electrode, and the third floating electrode overlaps with a portion of the second internal electrode and overlaps with a portion of the first floating electrode. a/L is 0.113 or more, where L is a length of the capacitor body, and a is a distance between the first floating electrode and the first inner electrode or the second inner electrode.

Description

Multilayer capacitor and board having the same mounted thereon

This application claims the benefit of priority from korean patent application No. 10-2020-0175198, filed on korean intellectual property office at 12/15/2020 and korean patent application No. 10-2021-0171498, filed on korean intellectual property office at 12/3/2021, the entire disclosures of which are incorporated herein by reference for all purposes.

Technical Field

The present disclosure relates to a multilayer capacitor and a board on which the multilayer capacitor is mounted.

Background

In recent years, as the popularity of environmentally friendly vehicles and electric vehicles has rapidly increased, the importance of a power drive system inside the vehicle has increased, and thus, the demand for a multilayer capacitor required for a power drive system for an electric device has also increased.

With such a multilayer capacitor for use in the field of electric power, a high capacity can be achieved, excellent durability against vibration and deformation is required, and it is designed to be usable under a high voltage.

As a method for increasing the withstand voltage of the multilayer capacitor, there is a method of dividing voltage using a floating electrode.

However, in this case, there may be a problem that the reliability of the multilayer capacitor is deteriorated.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

Exemplary embodiments provide a multilayer capacitor in which a certain level of reliability can be secured while increasing withstand voltage characteristics by using floating electrodes, and a board on which the multilayer capacitor is mounted.

According to an exemplary embodiment, a multilayer capacitor includes: a capacitor body having first and second surfaces opposite to each other, third and fourth surfaces connected to the first and second surfaces and opposite to each other, and fifth and sixth surfaces connected to the first and second surfaces, connected to the third and fourth surfaces, and opposite to each other, the capacitor body including a plurality of first dielectric layers, a plurality of second dielectric layers, and a plurality of internal electrodes stacked; and first and second external electrodes disposed on the third and fourth surfaces of the capacitor body, respectively. The inner electrode includes: first and second internal electrodes disposed on the first dielectric layer and spaced apart from each other in the first direction, and connected to the first and second external electrodes, respectively; a first floating electrode disposed on the first dielectric layer and between the first and second internal electrodes; and a second floating electrode and a third floating electrode disposed on the second dielectric layer and spaced apart from each other in the first direction. The second floating electrode overlaps with a portion of the first internal electrode and with a portion of the first floating electrode, and the third floating electrode overlaps with a portion of the second internal electrode and with a portion of the first floating electrode. a/L is greater than or equal to 0.113, where L is a length of the capacitor body in the first direction, and a is a distance between the first floating electrode and the first inner electrode or a distance between the first floating electrode and the second inner electrode.

b/L may be greater than or equal to 0.09, where b is a distance between the second floating electrode and the third surface of the capacitor body or a distance between the third floating electrode and the fourth surface of the capacitor body.

c/W may be greater than or equal to 0.138, where W is a length of the capacitor body in the second direction, and c is a distance between one of the first internal electrode, the second internal electrode, and the first floating electrode and the fifth surface or the sixth surface of the capacitor body in the second direction.

The first external electrode may include a first connection part and a first band part, the second external electrode may include a second connection part and a second band part, the first and second connection parts being disposed on the third and fourth surfaces of the capacitor body, respectively, and connected to the first and second internal electrodes, respectively, the first and second band parts extending from the first and second connection parts, respectively, to a portion of the first surface of the capacitor body.

The first to third floating electrodes may be spaced apart from the third to sixth surfaces, the first external electrode may be connected to the first internal electrode, and the second external electrode may be connected to the second internal electrode.

The second floating electrode may partially overlap with the first inner electrode and the first floating electrode, and the third floating electrode may partially overlap with the second inner electrode and the first floating electrode, in a stacking direction of the plurality of first dielectric layers and the plurality of second dielectric layers.

According to an exemplary embodiment, a board on which a multilayer capacitor is mounted includes: a substrate having a first electrode pad and a second electrode pad on one surface; and the above-mentioned multilayer capacitor, the said multilayer capacitor is mounted in a way that the said first external electrode and the said second external electrode of the said multilayer capacitor are connected to the said first electrode pad and said second electrode pad respectively.

According to an exemplary embodiment, a multilayer capacitor includes: a capacitor body having first and second surfaces opposite to each other, third and fourth surfaces connected to the first and second surfaces and opposite to each other in a first direction, and fifth and sixth surfaces connected to the first and second surfaces, connected to the third and fourth surfaces, and opposite to each other in a second direction, the capacitor body including a plurality of first dielectric layers, a plurality of second dielectric layers, and a plurality of internal electrodes stacked; and first and second external electrodes disposed on the third and fourth surfaces of the capacitor body, respectively. The plurality of inner electrodes include: first and second internal electrodes disposed on the first dielectric layer and spaced apart from each other in the first direction, and connected to the first and second external electrodes, respectively; a first floating electrode disposed on the first dielectric layer and between the first and second internal electrodes; and a second floating electrode and a third floating electrode disposed on the second dielectric layer and spaced apart from each other in the first direction. The second floating electrode overlaps with a portion of the first internal electrode and with a portion of the first floating electrode, and the third floating electrode overlaps with a portion of the second internal electrode and with a portion of the first floating electrode. b/L is greater than or equal to 0.09, where L is a length of the capacitor body in the first direction, and b is a distance between the second floating electrode and the third surface of the capacitor body or a distance between the third floating electrode and the fourth surface of the capacitor body.

According to an exemplary embodiment, a multilayer capacitor includes: a capacitor body having first and second surfaces opposite to each other, third and fourth surfaces connected to the first and second surfaces and opposite to each other in a first direction, and fifth and sixth surfaces connected to the first and second surfaces, connected to the third and fourth surfaces, and opposite to each other in a second direction, the capacitor body including a plurality of first dielectric layers, a plurality of second dielectric layers, and a plurality of internal electrodes stacked; and first and second external electrodes disposed on the third and fourth surfaces of the capacitor body, respectively. The plurality of inner electrodes include: first and second internal electrodes respectively disposed on the first dielectric layer and spaced apart from each other in the first direction, and respectively connected to the first and second external electrodes; a first floating electrode disposed on the first dielectric layer and between the first and second internal electrodes; and a second floating electrode and a third floating electrode disposed on the second dielectric layer and spaced apart from each other in the first direction. The second floating electrode overlaps with a portion of the first inner electrode and overlaps with a portion of the first floating electrode, and the third floating electrode overlaps with a portion of the second inner electrode and overlaps with a portion of the first floating electrode. c/W is greater than or equal to 0.138, where W is a length of the capacitor body in the second direction, and c is a distance between one of the first inner electrode, the second inner electrode, and the first floating electrode and the fifth surface or the sixth surface of the capacitor body in the second direction.

Drawings

The above and other aspects, features and advantages of the present inventive concept will be more clearly understood by reference to the following detailed description and the accompanying drawings, in which:

fig. 1 is a schematic perspective view of a multilayer capacitor according to an embodiment;

fig. 2A and 2B are plan views illustrating an arrangement structure of first to third floating electrodes and first and second internal electrodes applied to fig. 1;

FIG. 3 is a sectional view taken along line I-I' of FIG. 1;

FIG. 4 is a sectional view taken along line II-II' of FIG. 1;

fig. 5 is a graph showing Mean Time To Failure (MTTF) of a multilayer capacitor having a structure of internal electrodes and floating electrodes according to an embodiment, which varies according to a ratio (a/L) of a distance a between a first floating electrode and a first or second internal electrode in the multilayer capacitor with respect to a length (L) of a capacitor body;

FIG. 6 is a graph showing the mean MTTF of each of the samples in FIG. 5;

fig. 7 is a graph showing an MTTF of a multilayer capacitor having a structure of an internal electrode and a floating electrode according to an embodiment, which varies according to a ratio (b/L) of a distance b between a first floating electrode or a second floating electrode in the multilayer capacitor and one surface of a capacitor body in a length direction with respect to a length (L) of the capacitor body;

FIG. 8 is a graph showing the mean MTTF of each of the samples in FIG. 7;

fig. 9 is a graph showing an MTTF of a multilayer capacitor having a structure of an internal electrode and a floating electrode according to an embodiment, which varies according to a ratio (c/W) of a distance c between a first floating electrode or a second floating electrode in the multilayer capacitor and one surface of a capacitor body in a width direction with respect to a width (W) of the capacitor body;

FIG. 10 is a graph showing the mean MTTF of each of the samples in FIG. 9; and

fig. 11 is a perspective view schematically illustrating a bonding structure of a multilayer capacitor and a substrate according to an embodiment.

Detailed Description

The following detailed description is provided to assist the reader in obtaining a thorough understanding of the methods, devices, and/or systems described herein. Various changes, modifications, and equivalents of the methods, apparatus, and/or systems described herein will, however, be apparent to those of ordinary skill in the art. The order of operations described herein is merely an example and is not limited to the order set forth herein, but rather, variations may be made in addition to the operations which must occur in a particular order which will be readily apparent to those of ordinary skill in the art. Further, descriptions of functions and configurations well known to those of ordinary skill in the art may be omitted for the sake of clarity and conciseness.

The features described herein may be embodied in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein have been provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

Here, it is noted that the use of the term "may" with respect to an example or embodiment (e.g., with respect to what an embodiment or example may include or implement) means that there is at least one embodiment or example that includes or implements such a feature, and is not limited to all embodiments or examples including or implementing such a feature.

Throughout the specification, when an element such as a layer, region or substrate is described as being "on," connected to "or" coupled to "another element, the element may be directly" on, "connected to" or "coupled to" the other element, or one or more other elements may be present therebetween. In contrast, when an element is referred to as being "directly on," "directly connected to" or "directly coupled to" another element, there are no other elements intervening therebetween.

As used herein, the term "and/or" includes any one of the associated listed items or any combination of any two or more of the items.

Although terms such as "first", "second", and "third" may be used herein to describe various elements, components, regions, layers or sections, these elements, components, regions, layers or sections should not be limited by these terms. Rather, these terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section referred to in the examples described herein could also be referred to as a second element, component, region, layer or section without departing from the teachings of the examples.

Spatially relative terms, such as "above," "upper," "lower," and "below," may be used herein for ease of description to describe one element's relationship to another element as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "upper" relative to another element would then be "below" or "lower" relative to the other element. Thus, the term "above" includes both an orientation of above and below, depending on the spatial orientation of the device. The device may also be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative terms used herein should be interpreted accordingly.

The terminology used herein is for the purpose of describing various examples only and is not intended to be limiting of the disclosure. The singular is intended to include the plural unless the context clearly indicates otherwise. The terms "comprises," "comprising," and "having" specify the presence of stated features, quantities, operations, elements, components, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, elements, components, and/or combinations thereof.

Due to manufacturing techniques and/or tolerances, the shapes shown in the drawings may vary. Thus, the examples described herein are not limited to the specific shapes shown in the drawings, but include changes in shape that occur during manufacturing.

The features of the examples described herein may be combined in various ways that will be readily understood after having obtained an understanding of the disclosure of the present application. Further, while the examples described herein have a variety of configurations, other configurations are possible that will be readily appreciated after understanding the disclosure of the present application.

The figures may not be drawn to scale and the relative sizes, proportions and depictions of the elements in the figures may be exaggerated for clarity, illustration and convenience.

In addition, components having the same function within the scope of the same spirit shown in the drawings of the embodiments will be described using the same reference numerals.

When defining directions in the present disclosure, in fig. 1, X is a length direction, Y is a width direction, and Z is a thickness direction. In addition, in the following description, the X direction may also be described as a first direction, and the Y direction may also be described as a second direction.

Fig. 1 is a schematic perspective view of a multilayer capacitor according to an embodiment, fig. 2A and 2B are plan views illustrating an arrangement structure of first to third floating electrodes and first and second internal electrodes applied to fig. 1, fig. 3 is a sectional view taken along line I-I 'of fig. 1, and fig. 4 is a sectional view taken along line II-II' of fig. 1.

Referring to fig. 1 to 4, a multilayer capacitor 100 according to an embodiment includes: a capacitor body 110 including a plurality of dielectric layers 111 and a plurality of internal electrodes; and first and second external electrodes 130 and 140.

In this case, the internal electrodes include a first internal electrode 121, a second internal electrode 122, a first floating electrode 123, a second floating electrode 124, and a third floating electrode 125.

The capacitor body 110 is formed by sintering after alternately stacking a plurality of first dielectric layers 111 and a plurality of second dielectric layers 112 in the Z direction, and the adjacent first and second dielectric layers 111 and 112 may be integrated such that the boundary therebetween may not be confirmed without a Scanning Electron Microscope (SEM). In this case, the capacitor body 110 may have a substantially hexahedral shape. The capacitor body 110 may include first and second surfaces 1 and 2 opposite in a third direction (Z direction), third and fourth surfaces 3 and 4 connected to the first and second surfaces 1 and 2 and opposite in the first direction (X direction), and fifth and sixth surfaces 5 and 6 connected to the first to fourth surfaces 1 to 4 and opposite in the second direction (Y direction).

The first dielectric layer 111 and the second dielectric layer 112 may include a ceramic material having a high dielectric constant, such as barium titanate (BaTiO)₃) A base ceramic powder, etc., but the materials of the first dielectric layer 111 and the second dielectric layer 112 are not limited thereto as long as sufficient capacitance can be obtained therewith.

In addition, various ceramic additives, organic solvents, plasticizers, binders, and dispersants may also be added to the materials of the first and second dielectric layers 111 and 112 together with the ceramic powder.

In this case, the ceramic additive may be at least one of transition metal oxide, transition metal carbide, rare earth element, magnesium (Mg), and aluminum (Al).

Referring to fig. 3 and 4, in a cross section of the multilayer capacitor 100, a portion where the internal electrode is not formed may be defined as an edge portion (margin portion).

In this case, among the edge portions, edge portions located in upper and lower portions of the capacitor main body 110 in the Z direction may be defined as an upper cover 113 and a lower cover 114.

The upper and lower caps 113 and 114 may be formed by sintering a plurality of ceramic sheets similarly to the first or second dielectric layer 111 or 112, and the structure of the upper and lower caps 113 and 114 may be similar to that of the first or second dielectric layer 111 or 112 located at the center of the capacitor body 110 except that the internal electrode is not formed.

In this embodiment, the first internal electrode 121, the second internal electrode 122, and the first floating electrode 123 are disposed on one first dielectric layer 111, and the second floating electrode 124 and the third floating electrode 125 are disposed on one second dielectric layer 112.

The first to third internal electrodes 121, 122, 123, 124, and 125 are formed using a conductive metal, and at least one of, for example, silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), copper (Cu), and an alloy thereof may be used as the conductive metal, and the present disclosure is not limited thereto.

The first and second internal electrodes 121 and 122 are electrodes to which voltages having different polarities are applied, and are formed to be spaced apart from each other in the X direction on at least one surface of one ceramic sheet forming one first dielectric layer 111, and are disposed in the capacitor body 110 to be drawn through the third and fourth surfaces 3 and 4, respectively, the third and fourth surfaces 3 and 4 being both surfaces of the capacitor body 110 in the length direction.

The first floating electrode 123 is disposed on the first dielectric layer 111 and spaced apart from the first and second internal electrodes 121 and 122 in the X direction, and is also disposed spaced apart from the third to sixth surfaces 3 to 6 of the capacitor body 110.

The second floating electrode 124 and the third floating electrode 125 are disposed on the second dielectric layer 112, alternately disposed in the capacitor body 110 with the first inner electrode 121, the second inner electrode 122, and the first floating electrode 123 in the Z direction, and disposed on the single second dielectric layer 112 to be spaced apart from each other in the X direction.

In addition, the second floating electrode 124 and the third floating electrode 125 are also disposed to be spaced apart from the third surface 3 to the sixth surface 6 of the capacitor body.

In this case, one end of the second floating electrode 124 overlaps a portion of the first inner electrode 121 in the Z direction, and the other end of the second floating electrode 124 overlaps a portion of the first floating electrode 123 in the Z direction.

One end of the third floating electrode 125 overlaps a portion of the second inner electrode 122 in the Z direction, and the other end of the third floating electrode 125 overlaps a portion of the first floating electrode 123 in the Z direction.

On the other hand, the lengths of the first, second, and first floating electrodes 121, 122, and 123 in the Y direction may be greater than the lengths of the second and third floating electrodes 124 and 125 in the Y direction.

When a voltage is applied to the first and second external electrodes according to the structure of the internal electrode, the multilayer capacitor may form a capacitance.

In addition, the multilayer capacitor 100 of the present embodiment may include first and second external electrodes 130 and 140 formed on the third and fourth surfaces 3 and 4 of the capacitor body 110 in the X direction, respectively, and in contact with and electrically connected to the first and second internal electrodes 121 and 122 exposed through the third and fourth surfaces 3 and 4 of the capacitor body 110 in the X direction, respectively.

The first external electrode 130 includes a first conductive layer 131 formed using a conductive metal, the second external electrode 140 includes a second conductive layer 141 formed using a conductive metal, and the first conductive layer 131 and the second conductive layer 141 may be formed using, for example, one of silver (Ag), lead (Pb), platinum (Pt), nickel (Ni), copper (Cu), and an alloy thereof, and the disclosure is not limited thereto.

The first conductive layer 131 may include a first connection portion 131a and a first band portion 131b, the second conductive layer 141 may include a second connection portion 141a and a second band portion 141b, the first and second connection portions 131a and 141a are formed on the third and fourth surfaces 3 and 4 of the capacitor body 110, respectively, and are connected to the first and second internal electrodes 121 and 122, respectively, and the first and second band portions 131b and 141b extend from the first and second connection portions 131a and 141a to a portion of the first surface 1 of the capacitor body 110, respectively.

In this case, the first band part 131b and the second band part 141b may further extend to a portion of the fifth surface 5 of the capacitor body 110, a portion of the sixth surface 6 of the capacitor body 110, and a portion of the second surface 2 to increase adhesive strength.

In addition, in the first and second external electrodes 130 and 140, if necessary, a first plating layer 132 and a second plating layer 142 may be formed to cover the first and second conductive layers 131 and 141, respectively.

The first plating layer 132 may include a first nickel (Ni) plating layer and a first tin (Sn) plating layer, and the second plating layer 142 may include a second nickel (Ni) plating layer and a second tin (Sn) plating layer, the first and second nickel (Ni) plating layers being formed on the first and second conductive layers 131 and 141, respectively, and the first and second tin (Sn) plating layers being formed on the first and second nickel plating layers, respectively.

The first plating layer 132 and the second plating layer 142 are provided to increase the strength of mutual adhesion when the multilayer capacitor 100 is mounted on a printed circuit board or the like by solder.

In addition, the first plating layer 132 may include a 1-1 connection part 132a and a 1-2 band part 132b, and the second plating layer 142 may include a 2-1 connection part 142a and a 2-2 band part 142 b.

The 1-1 connection part 132a is a portion formed on the first connection part 131a of the first conductive layer 131, and the 1-1 band part 132b is a portion extending from the 1-1 connection part 132a to a portion of the first surface 1 of the capacitor body 110.

In this case, the 1-1 band part 132b may cover the first band part 131b, and may further extend to a portion of the fifth surface 5 of the capacitor body 110, a portion of the sixth surface 6 of the capacitor body 110, and a portion of the second surface 2 to increase adhesive strength, etc.

The 2-1 connection part 142a is a portion formed on the second connection part 141a of the second conductive layer 141, and the 2-1 strap part 142b is a portion extending from the 2-1 connection part 142a to a portion of the first surface 1 of the capacitor body 110.

In this case, the 2-1 band part 142b covers the second band part 141b, and may further extend to a portion of the fifth surface 5 of the capacitor body 110, a portion of the sixth surface 6 of the capacitor body 110, and a portion of the second surface of the capacitor body 110 to increase adhesive strength, etc.

According to this embodiment, since the internal electrode is provided with the floating electrode structure, the multilayer capacitor can realize a high voltage and can secure a certain level of reliability by the voltage dividing method.

In the multilayer capacitor having the floating electrode structure, the reliability of the multilayer capacitor varies depending on the distance between the floating electrode and the first or second internal electrode (e.g., parameter a) and the margin (margin) of the internal electrode (e.g., parameter b or c), the distance between the floating electrodes, and the like.

In this embodiment, the reliability of such a high voltage product can be further improved by adjusting the margin of the inner electrodes or the distance between the inner electrodes at an appropriate ratio.

The following table shows a comparison of Mean Time To Failure (MTTF) of the multilayer capacitor, which varies according to the size of the capacitor body, the interval of the inner electrodes, the margin, and the like.

The MTTF is the mean time to failure obtained by measuring the simple operating time or the equipment use time at 105 ℃ and 1.5 Vr.

[ Table 1]

In table 1, when the length of the capacitor body in the X direction is defined as L, the width of the capacitor body in the Y direction is defined as W, the distance between the first floating electrode and the first inner electrode or the distance between the first floating electrode and the second inner electrode is defined as a, the distance between the second floating electrode and the third surface of the capacitor body or the distance between the third floating electrode and the fourth surface of the capacitor body is defined as b, and the distance between one of the first inner electrode, the second inner electrode, and the first floating electrode and the fifth surface or the sixth surface of the capacitor body is defined as c, a change in MTTF according to the change of a/L is shown.

In this case, the multilayer capacitor used in the test had L of 2.22mm, W of 1.45mm, b of 0.25mm, and c of 0.25 mm.

In one example, the length L of the capacitor body in the X direction may refer to: in an image of a cross section of the capacitor body in the X-Z plane at a central portion of the capacitor in the Y direction obtained by an optical microscope or SEM, a maximum length of lengths of a plurality of line segments parallel to the X direction connecting between outermost boundary lines of the capacitor body, or alternatively, an average of the lengths of the plurality of line segments.

In one example, the width W of the capacitor body in the Y direction may refer to: in an image of a cross section of the capacitor body in the Y-Z plane at a central portion of the capacitor in the X direction obtained by an optical microscope or SEM, a maximum length of lengths of a plurality of line segments parallel to the Y direction connecting between outermost boundary lines of the capacitor body, or alternatively, an average of the lengths of the plurality of line segments. Alternatively, the width W of the capacitor body in the Y direction may be measured using a micrometer or a caliper.

In one example, the measurement of the parameter a, the parameter b, the parameter c, and the like may be performed based on the optical microscope or SEM image of the respective cross section described above. In one example, parameter a, parameter b, parameter c, or the like may refer to a maximum of multiple measurements of the respective parameter measured at different locations, or alternatively, an average of the multiple measurements. Other cross-sections, other measurement methods, or other measurement tools understood by one of ordinary skill in the art may be used even if not described in this disclosure.

Referring to Table 1 and FIGS. 5 and 6 (in FIG. 5, different legends indicate different a), it can be seen that MTTF has a minimum value in #2 where a/L is 9.0%, and MTTF gradually increases from #3 where a/L is 11.3%.

Therefore, when the length of the capacitor body in the X direction is defined as L, and the distance between the first floating electrode and the first inner electrode or the distance between the first floating electrode and the second inner electrode is defined as a, a/L may be 0.113 or more.

[ Table 2]

Table 2 shows a change in MTTF according to a change in b/L when a distance between the second floating electrode and the third surface of the capacitor body or a distance between the third floating electrode and the fourth surface of the capacitor body is defined as b.

In this case, the size of the multilayer capacitor used in the test was the same as in the previous test, and L was 2.22mm and W was 1.45 mm. Further, by applying #3 of table 1 (critical point in the previous test), a was made 0.25mm, and c was made 0.25 mm.

Referring to Table 2 and FIGS. 7 and 8 (in FIG. 7, different legends indicate different b's), it can be seen that MTTF gradually increases from #7 where b/L is 9.0%.

Accordingly, when a distance between the second floating electrode and the third surface of the capacitor body or a distance between the third floating electrode and the fourth surface of the capacitor body is defined as b, b/L may be 0.09 or more.

[ Table 3]

Table 3 shows a change in MTTF according to a change in c/W when the length of the capacitor body in the Y direction is defined as W, and the distance between one of the first internal electrode, the second internal electrode, and the first floating electrode and the fifth surface or the sixth surface of the capacitor body is defined as c.

In this case, the size of the multilayer capacitor used in the test was the same as that in the previous test, and L was 2.22mm, while W was 1.45 mm. Furthermore, a is 0.25mm and b is 0.25 mm.

Referring to Table 3 and FIGS. 9 and 10 (in FIG. 9, different c are indicated by different legend symbols), it can be seen that MTTF increases significantly from #12, where c/W is 13.8%.

Therefore, when the length of the capacitor body in the Y direction is defined as W and the distance between one of the first internal electrode, the second internal electrode, and the first floating electrode and the fifth surface or the sixth surface of the capacitor body is defined as c, c/W may be 0.138 or more.

Fig. 11 is a perspective view schematically illustrating a bonding structure of a multilayer capacitor and a substrate according to an embodiment.

Referring to fig. 11, a board with a multilayer capacitor mounted thereon according to the present embodiment includes: a substrate 210 on which the multilayer capacitor 100 is mounted; and first and second electrode pads 221 and 222 formed on the upper surface of the substrate 210 to be spaced apart from each other.

The multilayer capacitor 100 may be electrically connected to the substrate 210 by solders 231 and 232 in a state where the first and second external electrodes 130 and 140 are in contact with the first and second electrode pads 221 and 222, respectively, and are positioned on the first and second electrode pads 221 and 222.

In this case, according to an exemplary embodiment, the multilayer capacitor 100 may be a multilayer ceramic capacitor, and a detailed description thereof will be omitted below to avoid redundancy.

As described above, according to the exemplary embodiments, there is an effect of preventing a decrease in reliability caused by applying a floating electrode in a multilayer capacitor.

Although the present disclosure includes specific examples, it will be readily understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only and not for purposes of limitation. The description of features or aspects in each example will be considered applicable to similar features or aspects in other examples. Suitable results may be obtained if the described techniques were performed in a different order and/or if components in the described systems, architectures, devices, or circuits were combined in a different manner and/or replaced or added by other components or their equivalents. Therefore, the scope of the present disclosure is defined not by the specific embodiments but by the claims and their equivalents, and all modifications within the scope of the claims and their equivalents are to be construed as being included in the present disclosure.

Claims (21)

1. A multilayer capacitor, comprising:

a capacitor body having first and second surfaces opposite to each other, third and fourth surfaces connected to the first and second surfaces and opposite to each other in a first direction, and fifth and sixth surfaces connected to the first and second surfaces, connected to the third and fourth surfaces, and opposite to each other in a second direction, the capacitor body including a plurality of first dielectric layers, a plurality of second dielectric layers, and a plurality of internal electrodes stacked; and

first and second external electrodes disposed on the third and fourth surfaces of the capacitor body, respectively,

wherein the plurality of inner electrodes include:

first and second internal electrodes disposed on the first dielectric layer and spaced apart from each other in the first direction and connected to the first and second external electrodes, respectively;

a first floating electrode disposed on the first dielectric layer and between the first and second internal electrodes; and

a second floating electrode and a third floating electrode disposed on the second dielectric layer and spaced apart from each other in the first direction,

the second floating electrode is dropped down with a part of the first inner electrode and overlaps with a part of the first floating electrode,

the third floating electrode falls down with a part of the second inner electrode and overlaps with a part of the first floating electrode, and

a/L is greater than or equal to 0.113, where L is a length of the capacitor body in the first direction, and a is a distance between the first floating electrode and the first inner electrode or a distance between the first floating electrode and the second inner electrode.

2. The multilayer capacitor of claim 1, wherein b/L is greater than or equal to 0.09, wherein b is the distance between the second floating electrode and the third surface of the capacitor body or the distance between the third floating electrode and the fourth surface of the capacitor body.

3. The multilayer capacitor of claim 1, wherein c/W is greater than or equal to 0.138, where W is a length of the capacitor body in the second direction and c is a distance between one of the first internal electrode, the second internal electrode, and the first floating electrode and the fifth surface or the sixth surface of the capacitor body in the second direction.

4. The multilayer capacitor of claim 1, wherein b/L is greater than or equal to 0.09, wherein b is the distance between the second floating electrode and the third surface of the capacitor body or the distance between the third floating electrode and the fourth surface of the capacitor body, and

c/W is greater than or equal to 0.138, where W is a length of the capacitor body in the second direction, and c is a distance between one of the first inner electrode, the second inner electrode, and the first floating electrode and the fifth surface or the sixth surface of the capacitor body in the second direction.

5. The multilayer capacitor of claim 1, wherein the lengths of the first internal electrode, the second internal electrode, and the first floating electrode in the second direction are greater than the lengths of the second floating electrode and the third floating electrode in the second direction.

6. The multilayer capacitor as claimed in claim 1, wherein the first external electrode includes a first connection portion and a first band portion, the second external electrode includes a second connection portion and a second band portion,

the first connection portion and the second connection portion are respectively provided on the third surface and the fourth surface of the capacitor body and are respectively connected to the first internal electrode and the second internal electrode,

the first and second band portions extend from the first and second connection portions, respectively, to a portion of the first surface of the capacitor body.

7. The multilayer capacitor of claim 1, wherein the first, second, and third floating electrodes are spaced apart from the third, fourth, fifth, and sixth surfaces,

the first outer electrode is connected to the first inner electrode, and

the second external electrode is connected to the second internal electrode.

8. The multilayer capacitor of claim 1, wherein the first direction is perpendicular to the third and fourth surfaces of the capacitor body and the second direction is perpendicular to the fifth and sixth surfaces of the capacitor body.

9. The multilayer capacitor according to claim 1, wherein the second floating electrode partially overlaps the first internal electrode and partially overlaps the first floating electrode, and the third floating electrode partially overlaps the second internal electrode and partially overlaps the first floating electrode in a stacking direction of the plurality of first dielectric layers and the plurality of second dielectric layers.

10. A board having a multilayer capacitor mounted thereon, the board comprising:

a substrate having a first electrode pad and a second electrode pad on a surface thereof; and

multilayer capacitor according to one of claims 1 to 9,

wherein,

the multilayer capacitor is mounted in such a manner that the first and second external electrodes of the multilayer capacitor are connected to the first and second electrode pads, respectively.

11. A multilayer capacitor, comprising:

a capacitor body having first and second surfaces opposite to each other, third and fourth surfaces connected to the first and second surfaces and opposite to each other in a first direction, and fifth and sixth surfaces connected to the first and second surfaces, connected to the third and fourth surfaces, and opposite to each other in a second direction, the capacitor body including a plurality of first dielectric layers, a plurality of second dielectric layers, and a plurality of internal electrodes stacked; and

first and second external electrodes disposed on the third and fourth surfaces of the capacitor body, respectively,

wherein the plurality of inner electrodes include:

first and second internal electrodes disposed on the first dielectric layer and spaced apart from each other in the first direction and connected to the first and second external electrodes, respectively;

a first floating electrode disposed on the first dielectric layer and between the first and second internal electrodes; and

a second floating electrode and a third floating electrode disposed on the second dielectric layer and spaced apart from each other in the first direction,

the second floating electrode overlaps with a portion of the first inner electrode and overlaps with a portion of the first floating electrode,

the third floating electrode overlaps with a portion of the second inner electrode and with a portion of the first floating electrode, and

b/L is greater than or equal to 0.09, where L is a length of the capacitor body in the first direction, and b is a distance between the second floating electrode and the third surface of the capacitor body or a distance between the third floating electrode and the fourth surface of the capacitor body.

12. The multilayer capacitor of claim 11, wherein c/W is greater than or equal to 0.138, where W is a length of the capacitor body in the second direction and c is a distance between one of the first internal electrode, the second internal electrode, and the first floating electrode and the fifth surface or the sixth surface of the capacitor body in the second direction.

13. The multilayer capacitor of claim 11, wherein the lengths of the first, second and first floating electrodes in the second direction are greater than the lengths of the second and third floating electrodes in the second direction.

14. The multilayer capacitor as claimed in claim 11, wherein the first external electrode includes a first connection portion and a first band portion, the second external electrode includes a second connection portion and a second band portion,

the first connection portion and the second connection portion are respectively provided on the third surface and the fourth surface of the capacitor body and are respectively connected to the first internal electrode and the second internal electrode,

the first and second band portions extend from the first and second connection portions, respectively, to a portion of the first surface of the capacitor body.

15. The multilayer capacitor of claim 11, wherein the first, second, and third floating electrodes are spaced apart from the third, fourth, fifth, and sixth surfaces,

the first external electrode is connected to the first internal electrode, and

the second external electrode is connected to the second internal electrode.

16. The multilayer capacitor of claim 11, wherein, in a stacking direction of the plurality of first dielectric layers and the plurality of second dielectric layers, the second floating electrode partially overlaps the first internal electrode and partially overlaps the first floating electrode, and the third floating electrode partially overlaps the second internal electrode and partially overlaps the first floating electrode.

17. A multilayer capacitor, comprising:

a capacitor body having first and second surfaces opposite to each other, third and fourth surfaces connected to the first and second surfaces and opposite to each other in a first direction, and fifth and sixth surfaces connected to the first and second surfaces, connected to the third and fourth surfaces, and opposite to each other in a second direction, the capacitor body including a plurality of first dielectric layers, a plurality of second dielectric layers, and a plurality of internal electrodes stacked; and

first and second external electrodes disposed on the third and fourth surfaces of the capacitor body, respectively,

wherein the plurality of inner electrodes include:

first and second internal electrodes disposed on the first dielectric layer and spaced apart from each other in the first direction, and connected to the first and second external electrodes, respectively;

a first floating electrode disposed on the first dielectric layer and between the first and second internal electrodes; and

a second floating electrode and a third floating electrode disposed on the second dielectric layer and spaced apart from each other in the first direction,

the second floating electrode overlaps with a portion of the first inner electrode and overlaps with a portion of the first floating electrode,

the third floating electrode overlaps with a part of the second internal electrode and with a part of the first floating electrode, and

c/W is greater than or equal to 0.138, where W is a length of the capacitor body in the second direction, and c is a distance between one of the first internal electrode, the second internal electrode, and the first floating electrode and the fifth surface or the sixth surface of the capacitor body in the second direction.

18. The multilayer capacitor of claim 17, wherein the lengths of the first, second and first floating electrodes in the second direction are greater than the lengths of the second and third floating electrodes in the second direction.

19. The multilayer capacitor according to claim 17, wherein the first external electrode includes a first connection portion and a first band portion, the second external electrode includes a second connection portion and a second band portion,

the first connection portion and the second connection portion are respectively provided on the third surface and the fourth surface of the capacitor body and are respectively connected to the first internal electrode and the second internal electrode,

the first and second band portions extend from the first and second connection portions, respectively, to a portion of the first surface of the capacitor body.

20. The multilayer capacitor of claim 17, wherein the first, second, and third floating electrodes are spaced apart from the third, fourth, fifth, and sixth surfaces,

the first outer electrode is connected to the first inner electrode, and

the second external electrode is connected to the second internal electrode.

21. The multilayer capacitor of claim 17, wherein, in a stacking direction of the plurality of first dielectric layers and the plurality of second dielectric layers, the second floating electrode partially overlaps the first internal electrode and partially overlaps the first floating electrode, and the third floating electrode partially overlaps the second internal electrode and partially overlaps the first floating electrode.

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