阅读说明：本技术 多层陶瓷电子组件及其制造方法 (Multilayer ceramic electronic component and method for manufacturing the same ) 是由 尹瑄浩 金正烈 朴城汉 闵景基 朴荣圭 金锺翰 于 2018-12-07 设计创作，主要内容包括：本公开提供了一种多层陶瓷电子组件及其制造方法。所述多层陶瓷电子组件包括陶瓷主体,所述陶瓷主体包括介电层以及第一内电极和第二内电极,所述第一内电极和所述第二内电极彼此面对并且所述介电层介于所述第一内电极和所述第二内电极之间。所述第一内电极和所述第二内电极包括导电金属和添加剂。在所述陶瓷主体的长度-厚度(L-T)平面中的截面中,所述陶瓷主体的上部和下部中的所述第一内电极和所述第二内电极中的添加剂的含量与所述陶瓷主体的中部中的所述第一内电极和所述第二内电极中的添加剂的含量的比为约0.63至约1.03。(The present disclosure provides a multilayer ceramic electronic component and a method of manufacturing the same. The multilayer ceramic electronic component includes a ceramic main body including a dielectric layer and first and second internal electrodes facing each other with the dielectric layer interposed therebetween. The first and second internal electrodes include a conductive metal and an additive. A ratio of a content of the additive in the first and second internal electrodes in upper and lower portions of the ceramic main body to a content of the additive in the first and second internal electrodes in a middle portion of the ceramic main body is about 0.63 to about 1.03 in a cross section in a length-thickness (L-T) plane of the ceramic main body.)

1. A multilayer ceramic electronic component, comprising:

A ceramic body including a dielectric layer and first and second internal electrodes facing each other, the dielectric layer being interposed between the first and second internal electrodes, the first and second internal electrodes including a conductive metal and an additive,

Wherein, in a cross section of the ceramic main body along a length-thickness plane, a ratio of a content of the additive in the first and second internal electrodes in the upper and lower portions of the ceramic main body to a content of the additive in the first and second internal electrodes in the middle portion of the ceramic main body is 0.63 to 1.03.

2. The multilayer ceramic electronic component according to claim 1, wherein a ratio of a content of the additive to a content of the conductive metal in the first and second internal electrodes is 0.5% or more.

3. The multilayer ceramic electronic component according to claim 2, wherein a ratio of a content of the additive to a content of the conductive metal in the first and second internal electrodes is 0.5% to 3.0%.

4. The multilayer ceramic electronic component according to claim 1, wherein the first and second internal electrodes disposed in the middle portion of the ceramic main body occupy an area that is 40% to 60% of an area occupied by all of the first and second internal electrodes in the ceramic main body.

5. The multilayer ceramic electronic component according to claim 1, wherein the first and second internal electrodes provided in each of the upper and lower portions of the ceramic main body occupy an area that is 10% or less of an area occupied by all of the first and second internal electrodes from an uppermost internal electrode to a lowermost internal electrode.

6. The multilayer ceramic electronic component according to claim 1, wherein a thickness Te of each of the first and second internal electrodes satisfies the formula 0.1 μm ≦ Te ≦ 0.5 μm.

7. The multilayer ceramic electronic component of claim 1, wherein the additive comprises a ceramic material.

8. a method of manufacturing a multilayer ceramic electronic component, the method comprising:

Forming a ceramic green sheet;

Forming an internal electrode pattern on the ceramic green sheet using a conductive paste including a conductive metal, an additive, and 500ppm or less of sulfur;

Forming a ceramic laminate by laminating a plurality of ceramic green sheets, each including the internal electrode pattern; and

Forming a ceramic body including a plurality of dielectric layers and a plurality of internal electrodes by sintering the ceramic laminate,

Wherein, in a cross section of the ceramic main body taken along a length-thickness plane, a ratio of a content of the additive in the internal electrodes in upper and lower portions of the ceramic main body to a content of the additive in the internal electrodes in a middle portion of the ceramic main body is 0.63 to 1.03.

9. The method of manufacturing a multilayer ceramic electronic component according to claim 8, wherein a ratio of a content of the additive to a content of the conductive metal in the internal electrode is 0.5% or more.

10. The method of manufacturing a multilayer ceramic electronic component according to claim 9, wherein a ratio of a content of the additive to a content of the conductive metal in the internal electrode is 0.5% to 3.0%.

11. The method of manufacturing a multilayer ceramic electronic component according to claim 8, wherein the internal electrode in the middle portion of the ceramic main body occupies an area of 40% to 60% of an entire area occupied by the plurality of internal electrodes.

12. the method of manufacturing a multilayer ceramic electronic component according to claim 8, wherein the area occupied by the internal electrodes in each of the upper portion and the lower portion of the ceramic main body is 10% or less of the entire area occupied by the plurality of internal electrodes from an uppermost internal electrode to a lowermost internal electrode.

13. The method of manufacturing a multilayer ceramic electronic component according to claim 8, wherein the thickness Te of each of the internal electrodes satisfies the formula 0.1 μm Te ≦ 0.5 μm.

14. The method of fabricating a multilayer ceramic electronic component according to claim 8, wherein the additive comprises a ceramic material.

Technical Field

The present disclosure relates to a multilayer ceramic electronic component and a method of manufacturing the same, and more particularly, to a multilayer ceramic electronic component having improved reliability and a method of manufacturing the same.

Background

In general, an electronic component (such as a capacitor, an inductor, a piezoelectric element, a varistor, a thermistor, etc.) using a ceramic material includes a ceramic body formed using a ceramic material, internal electrodes formed in the ceramic body, and external electrodes mounted on a surface of the ceramic body and connected to the internal electrodes.

The multilayer ceramic capacitor includes a plurality of stacked dielectric layers, inner electrodes facing each other with the dielectric layers interposed therebetween, and outer electrodes electrically connected to the inner electrodes.

Multilayer ceramic capacitors are widely used as components of mobile communication devices such as computers, PDAs, cellular phones, etc. due to their small size, high capacitance ensured, and easy installation.

As technology advances, as electrical and electronic devices become increasingly more efficient, thinner, and smaller in size, there is a need for miniaturized, high efficiency, and high capacitance electronic components. In particular, since a high-speed CPU has been developed and electronic devices have been miniaturized, digitalized and highly efficient, a great deal of research and development has been conducted to realize a miniaturized and thinned multilayer ceramic capacitor having high capacitance and low impedance at high frequencies.

The multilayer ceramic capacitor can be manufactured by stacking a conductive paste for internal electrodes and ceramic green sheets via a sheet method, a printing method, or the like and simultaneously firing them.

However, in order to form the dielectric layer, the ceramic green sheet is sintered at a temperature higher than 1100 ℃, and the conductive paste may be sintered and shrunk at a lower temperature.

Therefore, when the ceramic green sheets are sintered, the internal electrodes may shrink beyond a desired size, and the internal electrodes may aggregate or crack (become discontinuous) with each other, and the connectivity of the internal electrodes may decrease.

In the case where the internal electrodes are aggregated or broken, the reliability of the multilayer ceramic capacitor is lowered, and when the connectivity of the internal electrodes is lowered, the capacitance of the multilayer ceramic capacitor is significantly reduced.

Disclosure of Invention

An aspect of the present disclosure provides a multilayer ceramic electronic component having improved reliability and a method of manufacturing the same.

According to an aspect of the present disclosure, a multilayer ceramic electronic component includes a ceramic main body including a dielectric layer and first and second internal electrodes facing each other with the dielectric layer interposed therebetween. The first and second internal electrodes include a conductive metal and an additive. A ratio of a content of the additive in the first and second internal electrodes in the upper and lower portions of the ceramic body to a content of the additive in the first and second internal electrodes in the middle portion is about 0.63 to about 1.03 in a cross section taken in a length-thickness (L-T) plane of the ceramic body.

according to another aspect of the present disclosure, a method of manufacturing a multilayer ceramic electronic component includes: forming a ceramic green sheet; forming an internal electrode pattern on the ceramic green sheet using a conductive paste including a conductive metal, an additive, and sulfur (S) of 500ppm or less; forming a ceramic laminate by laminating a plurality of ceramic green sheets, each including the internal electrode pattern; and forming a ceramic body including a plurality of dielectric layers and a plurality of internal electrodes by sintering the ceramic laminate. In a cross section taken in a length-thickness plane of the ceramic main body, a ratio of a content of the additive in the internal electrodes in the upper and lower portions of the ceramic main body to a content of the additive in the internal electrode disposed in the middle portion is about 0.63 to about 1.03.

Drawings

The above and other aspects, features and advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

Fig. 1 is a perspective view of an illustrative multilayer ceramic capacitor according to an example embodiment in the present disclosure.

Fig. 2 is a sectional view taken along line 2-2 in fig. 1.

Fig. 3 is a cross-sectional view taken along line 3-3 in fig. 1.

Fig. 4 is an enlarged view of dielectric layers and inner electrodes of a multilayer ceramic capacitor according to an example embodiment.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described as follows with reference to the accompanying drawings.

This disclosure may, however, be embodied in many different forms and should not be construed as limited to the particular embodiments set forth herein. Rather, these embodiments are 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. Therefore, the shapes and sizes of elements in the drawings may be exaggerated for clarity of description, and elements indicated by the same reference numerals in the drawings are the same elements.

Multilayer ceramic electronic component

One aspect of the present disclosure relates to a multilayer ceramic electronic component. The electronic component using the ceramic material may be a capacitor, an inductor, a piezoelectric element, a varistor, a thermistor, or the like. In the following description, a multilayer ceramic capacitor will be described as an example of a multilayer ceramic electronic component.

Fig. 1 is a perspective view of a multilayer ceramic capacitor according to an example embodiment.

Fig. 2 is a sectional view taken along line 2-2 in fig. 1.

Fig. 3 is a cross-sectional view taken along line 3-3 in fig. 1.

Referring to fig. 1, 2 and 3, the multilayer ceramic capacitor 100 may include a ceramic body 110 and first and second external electrodes 131 and 132 formed on an outer surface of the ceramic body 110, the ceramic body 110 including a dielectric layer 111 and a plurality of first and second internal electrodes 121 and 122 formed in the ceramic body 110 to face each other with the dielectric layer 111 interposed between the plurality of first and second internal electrodes 121 and 122.

In an exemplary embodiment, in fig. 1, a length direction of the multilayer ceramic capacitor may be defined as an L direction, a width direction may be defined as a W direction, and a thickness direction may be defined as a T direction. The thickness direction may be regarded as the same as the stacking direction in which the dielectric layers are stacked.

Although fig. 1 illustrates the ceramic main body 110 having a hexahedral shape, the shape is not limited in this respect. In other embodiments, the ceramic body 110 may have any desired shape, for example, may not be limited to any particular shape.

The ceramic main body 110 may be formed by laminating a plurality of dielectric layers 111.

The plurality of dielectric layers 111 forming the ceramic body 110 may be in a sintered state, and adjacent dielectric layers may be integrated such that the adjacent dielectric layers may be merged with each other and a boundary between the adjacent dielectric layers may be unclear.

The dielectric layer 111 can be formed by sintering a ceramic green sheet including ceramic powder.

The type of ceramic powder is not limited to any particular ceramic powder, and any ceramic powder known in the art may be used.

For example, the ceramic powder may include BaTiO3 ceramic powder, but the disclosure is not limited thereto.

In other examples, the ceramic powder may be or include (Ba1-xCax) TiO3, Ba (Ti1-yCay) O3, (Ba1-xCax) (Ti1-yZry) O3, or Ba (Ti1-yZry) O3 formed by applying Ca, Zr, or the like to BaTiO3, but the disclosure is not limited thereto.

Further, the ceramic green sheet may include transition metals, rare earth elements, magnesium (Mg), aluminum (Al), combinations thereof, and the like, in addition to the ceramic powder.

The thickness of the dielectric layer 111 may vary according to the capacitance design of the multilayer ceramic capacitor.

For example, the thickness of the dielectric layer 111 formed between two adjacent internal electrodes after sintering may be 0.6 μm or less, but is not limited thereto.

The first and second internal electrodes 121 and 122 may be formed in the ceramic main body 110.

The first and second internal electrodes 121 and 122 may be formed on the ceramic green sheets and laminated, and may be formed in the ceramic main body 110 by sintering, with the dielectric layer 111 interposed between the first and second internal electrodes 121 and 122.

The first and second internal electrodes 121 and 122 may be provided as a pair of electrodes having different polarities, and may face each other in a lamination direction of the dielectric layers (e.g., in a T direction in fig. 2).

As shown in fig. 2, the ends of the first and second internal electrodes 121 and 122 may be alternately exposed to the surface of the ceramic main body 110 in the length (L) direction.

Further, although not shown, the first and second internal electrodes 121 and 122 may have leads, and may be exposed to the same surface of the ceramic main body through the leads.

In addition, the first and second internal electrodes 121 and 122 may have leads and may be exposed to one or more surfaces of the ceramic main body through the leads.

The first and second external electrodes 131 and 132 may be formed on the outer surface of the ceramic body 110. For example, as shown, the first and second external electrodes 131 and 132 may be formed on the ends of the ceramic body 110 in the length (L) direction. The first and second external electrodes 131 and 132 may be electrically connected to the first and second internal electrodes 121 and 122, respectively.

Specifically, the first external electrode 131 is electrically connected to the first internal electrode 121 exposed to the surface of the ceramic body 110, and the second external electrode 132 is electrically connected to the second internal electrode 122 exposed to the surface of the ceramic body 110 opposite to the surface.

Although not shown, a plurality of external electrodes may be formed on respective ends of the ceramic body 110 and connected to respective first and second internal electrodes exposed on surfaces at the respective ends of the ceramic body.

The first and second external electrodes 131 and 132 may be formed using a conductive paste including metal powder.

The type of the metal powder included in the conductive paste may not be limited to any particular metal powder. For example, nickel (Ni), copper (Cu), or an alloy thereof may be used.

The thicknesses of the first and second external electrodes 131 and 132 may be determined according to the intended use, etc. For example, the thickness may be 10 μm to 50 μm.

The first and second internal electrodes 121 and 122 may include conductive metals and additives to prevent shrinkage of the internal electrodes during the sintering process.

fig. 4 is an enlarged view of the dielectric layer 111 and the inner electrodes 121(122) of the multilayer ceramic capacitor 100 according to an example embodiment.

Referring to fig. 4, according to an exemplary embodiment, the first and second internal electrodes 121 and 122 of the multilayer ceramic capacitor may include a portion referred to as a non-electrode portion (N). According to an exemplary embodiment, portions of the first and second internal electrodes 121 and 122 other than the non-electrode portion (N) may be referred to as electrode portions (E).

According to example embodiments, the non-electrode part (N) may be formed during a sintering process of the first and second internal electrodes 121 and 122, and may be formed by a composition of a conductive paste forming the internal electrodes.

The non-electrode portion (N) may include a ceramic additive. However, the embodiments are not limited in this respect.

Referring to fig. 4, the first and second internal electrodes 121 and 122 may include a conductive metal and an additive, and may include an electrode portion (E) including the conductive metal and a non-electrode portion (N) including the additive. The non-electrode portion (N) may not contribute to the capacitance (or alternatively, a capacitive effect) of the multilayer ceramic capacitor 100.

The type of conductive metal forming the first and second internal electrodes 121 and 122 may not be limited to any particular conductive metal. For example, base metals may be used.

The conductive metal may include one or more of nickel (Ni), manganese (Mn), chromium (Cr), cobalt (Co), aluminum (Al), or alloys thereof. However, the embodiments are not limited in this respect.

The additive may be the same material as that of the ceramic powder forming the dielectric layer 111. For example, barium titanate (BaTiO3) powder may be used, but the present disclosure is not limited thereto.

As another example, the additive may be or include barium titanate (BaTiO3), ZrO2, Al2O3, TiN, SiN, AlN, TiC, SiC, WC, and the like, but the disclosure is not limited thereto.

By adjusting the content of the additives included in the first and second internal electrodes 121 and 122, the strength of the internal electrodes 121 and 122 can be increased by controlling the non-electrode portion (N) in the first and second internal electrodes 121 and 122, and cracks can be restricted by reducing sintering shrinkage stress.

Specifically, in a cross-section (e.g., a view in fig. 2) of the ceramic main body 110 in a length-thickness (L-T) direction, a ratio of the content of the additive in the first and second internal electrodes 121 and 122 disposed in the upper and lower portions 120a and 120b of the ceramic main body 110 to the content of the additive in the first and second internal electrodes 121 and 122 disposed in the middle portion 120c of the ceramic main body 110 may be about 0.63 to about 1.03.

In order to prevent the shrinkage of the internal electrode (contraction/shrinkage), the related art uses a method of adding a ceramic additive to a conductive paste of the internal electrode or a method of adding sulfur (S) to the surface of a conductive metal to change the characteristics of nickel (Ni) when used in the internal electrode.

When a ceramic additive is added to the conductive paste of the internal electrode to limit the shrinkage of the internal electrode, a small amount of the additive is bound in the internal electrode, and the difference in the fraction of the additive disposed in each position of the internal electrode in the ceramic body is high. Therefore, it may be difficult to realize a small-sized multilayer ceramic capacitor having a high capacitance.

Further, when sulfur (S) is added to the surface of the conductive metal to change the characteristics of nickel (Ni), a small amount of the additive may remain in the inner electrode compared to the amount of the added sulfur (S). Furthermore, the bound additive is not uniformly dispersed. Therefore, it may be difficult to realize a small-sized multilayer ceramic capacitor having a high capacitance.

However, according to an exemplary embodiment, in a cross-section in a length-thickness (L-T) direction of the ceramic main body 110, since a ratio of the content of the additive in the first and second internal electrodes 121 and 122 disposed in the upper and lower portions of the ceramic main body 110 to the content of the additive in the first and second internal electrodes 121 and 122 disposed in the middle portion is about 0.63 to about 1.03, aggregation (or agglomeration) and breakage (disconnection) of the electrodes may be minimized. As a result, a multilayer ceramic capacitor having improved reliability and higher capacitance can be realized.

In the following description, a method of configuring a ratio of the content of the additive in the first and second internal electrodes 121 and 122 disposed in the upper and lower portions of the ceramic main body 110 to the content of the additive in the first and second internal electrodes 121 and 122 disposed in the middle portion to be about 0.63 to about 1.03 will be described.

In order to obtain the aforementioned content ratio, sulfur (S) may be added to the conductive paste of the internal electrode, and the content of sulfur (S) may be 500ppm or less, unlike the prior art. Wherein ppm represents parts per million (baseon weight) on a weight basis.

If the conductive paste for the internal electrode is nickel (Ni), particles of 180nm or less may be included, and the additive may also include a powder of particles of 30nm or less.

Since the conductive paste for the internal electrodes includes a sulfur (S) content of 500ppm or less and includes nickel (Ni) particles of 180nm or less and additive particles of 30nm or less, shrinkage (e.g., anisotropic shrinkage) of the internal electrodes may be minimized, and in addition, the additives may be relatively uniformly dispersed in the first and second internal electrodes 121 and 122 during the sintering process.

Therefore, according to an exemplary embodiment, a ratio of the content of the additive in the first and second internal electrodes 121 and 122 disposed in the upper and lower portions of the ceramic main body 110 to the content of the additive in the first and second internal electrodes 121 and 122 disposed in the middle portion of the ceramic main body 110 may be about 0.63 to about 1.03.

in general, additives may aggregate with each other during the heat treatment process, and the additives may be squeezed out (or released) when the inner electrode is sintered, and the additives may be adsorbed into the dielectric layer. Therefore, the thickness of the dielectric layer may increase, and it may be difficult to reduce the size of the multilayer ceramic electronic component.

according to an exemplary embodiment, since the conductive paste of the inner electrode includes a low content of sulfur (S) of 500ppm or less, a shrinkage initiation temperature of nickel (Ni) may be lowered, and thus, the additive may be bound in the inner electrode before the additive is aggregated.

Because the additive may be bound in the inner electrode at a relatively low temperature, the likelihood of the additive being squeezed out (or released) into the dielectric layer may be reduced.

Accordingly, since the additive may be bound before a difference in grain growth of the additive occurs in each location due to a temperature change, a change in dispersion of the additive in each location in the internal electrode in the ceramic main body may be minimized.

Further, by using the particulate additive, the possibility that the additive is extruded (or released) into the dielectric layer can be low, and therefore, a multilayer ceramic electronic component in which the additive is uniformly dispersed in the internal electrode can be obtained.

by satisfying the above conditions, a multilayer ceramic electronic component having higher capacitance and improved reliability can be obtained.

Further, since the thermal stability of the internal electrodes may be relatively increased based on the above-described conditions, the thickness (T) of the dielectric layer may be further reduced as compared to the reduction in the width (W) direction and the length (L) direction when being sintered, so that the thickness of the dielectric layer may be reduced. Accordingly, the capacitance can be increased.

If the ratio of the content of the additives in the first and second internal electrodes 121 and 122 disposed in the upper and lower portions of the ceramic main body 110 to the content of the additives in the first and second internal electrodes 121 and 122 disposed in the middle portion is less than about 0.63, the content of sulfur (S) included in the paste of the internal electrodes may exceed 500ppm, and as a result, reliability may be reduced due to a reduction in capacitance, an increase in cracks, and the like.

If the ratio of the content of the additives in the first and second internal electrodes 121 and 122 disposed in the upper and lower portions of the ceramic main body 110 to the content of the additives in the first and second internal electrodes 121 and 122 disposed in the middle portion exceeds 1.03, the content of sulfur (S) included in the paste of the internal electrodes may be too low to effectively prevent the shrinkage of the internal electrodes, and thus, there may be problems of reliability such as mismatch, cracks, and the like between the internal electrodes and the dielectric layers.

The ratio of the content of the additive bound in the first and second internal electrodes 121 and 122 to the content of the conductive metal may be about 0.5% or more, and more preferably, the ratio of the content of the additive bound in the first and second internal electrodes 121 and 122 to the content of the conductive metal may be about 0.5% to about 3.0%.

When the content ratio of the additive bound (or otherwise retained) to the conductive metal in the first and second internal electrodes 121 and 122 is about 0.5% to about 3.0%, a multilayer ceramic electronic component having high capacitance and high reliability can be obtained.

If the content ratio of the additive to the conductive metal bound (or retained) in the first and second internal electrodes 121 and 122 is less than about 0.5%, reliability may be reduced because cracks may increase during sintering.

If the content ratio of the additive to the conductive metal bound (or retained) in the first and second internal electrodes 121 and 122 exceeds about 3.0%, the content of the additive may increase, and this may cause a decrease in capacitance due to an increase in the non-electrode part (N).

Referring back to fig. 2 and 3, the first and second internal electrodes disposed in the middle portion 120c of the ceramic main body 110 may occupy an area of about 40% to about 60% of the entire area occupied by all of the first and second internal electrodes 121 and 122.

Here, for the purpose of discussion, the first and second internal electrodes disposed in the middle portion 120c of the ceramic main body 110 may generally refer to the internal electrodes 121 and 122 generally located in a central region of the ceramic main body 110 with respect to a lamination direction (e.g., a thickness (T) direction) of the first and second internal electrodes 121 and 122.

The first and second internal electrodes disposed in the upper portion 120a and the lower portion 120b of the ceramic main body 110 (with respect to the thickness (T) direction) may each occupy 10% of the entire area occupied by the first and second internal electrodes 121 and 122 from the uppermost internal electrode (121/122) to the lowermost internal electrode (121/122).

The first and second internal electrodes disposed in each of the upper and lower portions 120a and 120b of the ceramic main body 110 may include internal electrodes disposed at or adjacent to outermost portions of the ceramic main body 110 in a thickness (T) direction of the first and second internal electrodes 121 and 122. The first and second internal electrodes disposed in each of the upper and lower portions 120a and 120b of the ceramic main body 110 occupy an area of about 10% or less of an area occupied by all of the first and second internal electrodes 121 and 122. In an example, the area occupied by all of the first and second internal electrodes 121 and 122 is measured from the topmost internal electrode to the bottommost internal electrode as viewed in the thickness (T) direction.

By measuring the area of the non-electrode portion including the additive, it may be determined whether the ratio of the content of the additive in the first and second internal electrodes 121 and 122 disposed in the upper and lower portions of the ceramic main body 110 to the content of the additive in the first and second internal electrodes 121 and 122 disposed in the middle portion is about 0.63 to about 1.03.

Referring to fig. 4, the thickness (Td) of the dielectric layer 111 may be 0.6 μm or less.

The thickness (Te) of the first and second inner electrodes 121 and 122 may be determined according to the intended use. For example, the thickness can be about 0.7 μm or less, about 0.1 μm to about 0.5 μm, or about 0.3 μm to about 0.5 μm.

The thickness (Te) of the first and second internal electrodes 121 and 122 may refer to an average thickness of the first and second internal electrodes 121 and 122 disposed between the dielectric layers 111.

The average thickness of the first and second internal electrodes 121 and 122 may be measured by scanning a cross-section taken along a length-thickness (L-T) plane of the ceramic main body 110 through a Scanning Electron Microscope (SEM).

For example, the average value may be obtained by measuring the thickness of a desired inner electrode extracted from an image obtained by scanning a cross section of a length-thickness (L-T) plane using a Scanning Electron Microscope (SEM) at thirty points having a constant interval in the width direction.

Thirty points having a constant interval may be measured at the capacitance forming part (the region of overlap between the first and second internal electrodes 121 and 122).

Further, in addition to the above, in the case where an average value is measured in 10 or more internal electrodes, the average thickness of the internal electrodes may be further generalized.

Method for manufacturing multilayer ceramic capacitor

According to another exemplary embodiment, a method of manufacturing a multilayer ceramic electronic component may include forming ceramic green sheets, forming internal electrode patterns using a conductive paste including a conductive metal, an additive, and sulfur (S) in an amount of about 500ppm or less, forming a ceramic laminate by stacking the ceramic green sheets on which the internal electrode patterns are formed, and forming a ceramic body including dielectric layers and internal electrodes by sintering the ceramic laminate. In a cross section taken along a length-thickness plane of the ceramic main body, among the first and second internal electrodes, a ratio of a content of the additive in the first and second internal electrodes disposed in upper and lower portions of the ceramic main body to a content of the additive in the first and second internal electrodes disposed in a middle portion is about 0.63 to about 1.03.

According to another exemplary embodiment, the method of manufacturing a multilayer ceramic capacitor may further include forming an inner electrode pattern using a conductive paste including a conductive metal, an additive, and sulfur (S) in an amount of about 500ppm or less.

In order to change the characteristics of nickel (Ni), sulfur (S) may be added to the surface of the conductive metal, but, unlike the prior art, 500ppm or less of sulfur (S) may be included in the conductive paste.

According to another exemplary embodiment, since the conductive paste for the inner electrode includes 500ppm or less of sulfur (S), the shrinkage initiation temperature of nickel (Ni) may be lowered, and thus, the additive may be bound (or otherwise remain) in the inner electrode before the additive is aggregated.

According to the above-described example embodiments, since the conductive paste for the internal electrode includes a low content of sulfur (S), the additive may be bound (or retained) in the internal electrode at a lower temperature, and thus, the possibility of the additive being released into the dielectric layer may be reduced.

Accordingly, since the additive is retained before the difference in grain growth of the additive occurs in each position caused by the temperature change, the variation in dispersion of the additive in each position of the internal electrode in the ceramic main body can be reduced.

Further, since the use of the particulate additive can reduce the possibility of the additive being released into the dielectric layer, a multilayer ceramic electronic component having the additive uniformly dispersed in the internal electrode can be obtained.

By satisfying the above conditions, a multilayer ceramic electronic component having higher capacitance and higher reliability can be realized.

With respect to the method of manufacturing a multilayer ceramic capacitor in the present disclosure, a general method of manufacturing a multilayer ceramic capacitor may be applied to elements other than the specific parts described above. Therefore, a detailed description thereof is omitted for the sake of brevity.

Example embodiments

Table 1 below shows the content of sulfur (S) in the conductive paste, all average fractions of additives bound in the internal electrodes, and whether cracks occur due to shrinkage and a target capacitance is obtained in terms of the ratio of the content of the additives of the internal electrodes in the upper and lower portions to the content of the additives of the internal electrodes in the middle portion of the multilayer ceramic capacitor.

A multilayer ceramic capacitor is manufactured by performing the following steps.

The dielectric layer is manufactured by using a plurality of ceramic green sheets formed by coating a carrier film with a slurry including a powder such as barium titanate (BaTiO3) having an average particle size of about 0.05 μm to about 0.2 μm, and then drying.

Then, a conductive paste for an internal electrode including nickel particles, a ceramic additive, and sulfur (S) was formed according to the ratio in table 1.

The internal electrodes are formed by coating ceramic green sheets with a conductive paste for internal electrodes via a screen printing process, and a laminate is formed by laminating 200 to 300 layers of the ceramic green sheets.

Pieces of "0603" size were made by cutting and pressing, and the pieces were sintered at a temperature range of about 1050 ℃ to about 1200 ℃ in a reducing atmosphere with about 0.1% or less of H2.

The multilayer ceramic capacitor was manufactured through processes including a process of forming external electrodes, a plating process, and the like, and electrical properties were evaluated. In the case where the capacitance was decreased by 10% or more when the capacitance of the designed sheet was measured (for example, in the case where the capacitance value was 4.23 μ F or less when the target capacitance was 4.7 μ F), it was determined that the desired capacitance was not obtained.

The presence of cracks (as seen in a cross section of a width and thickness (W-T) plane) around the boundary portion between the edge portion of the unprinted inner electrode and the capacitance forming portion of the printed inner electrode was observed using an optical microscope.

In the experimental data in table 1, the thickness ratio between the internal electrode and the dielectric layer was 1: 1.

TABLE 1

*: comparative example, o: good, x: defect of

Referring to table 1, in the comparative example of sample 1 and sample 2, among the first and second internal electrodes 121 and 122, the ratio of the content of the additive in the first and second internal electrodes 121 and 122 disposed in the upper and lower portions to the content of the additive in the first and second internal electrodes 121 and 122 disposed in the middle portion is about 0.63 or less, and the content of sulfur (S) included in the paste for the internal electrodes exceeds 500 ppm. In this case, the reliability of the capacitor may be reduced due to a decrease in capacitance, an increase in cracks during sintering, and the like.

If the ratio of the content of the additives in the first and second internal electrodes 121 and 122 disposed in the upper and lower portions to the content of the additives in the first and second internal electrodes 121 and 122 disposed in the middle portion exceeds 1.03 among the first and second internal electrodes 121 and 122, although not indicated in table 1, shrinkage of the internal electrodes is not effectively prevented because the content of sulfur (S) included in the paste of the internal electrodes is too low, and as a result, reliability may be poor due to mismatch, cracks, and the like between the internal electrodes and the dielectric layers.

In samples 3, 4 and 5 prepared according to the example embodiments disclosed herein, when the measurement ranges suggested in the present disclosure were satisfied, the desired capacitance was obtained and no cracks were observed after the sintering process. Therefore, a multilayer ceramic capacitor having improved reliability and higher capacitance can be obtained.

According to an aspect of the present disclosure, among the internal electrodes, a multilayer ceramic electronic component having higher capacitance and higher reliability may be obtained by adjusting a ratio of a content of an additive in the internal electrodes disposed in the upper and lower portions of the ceramic main body to a content of the additive in the internal electrodes disposed in the middle portion of the ceramic main body to about 0.63 to about 1.03.

While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and changes may be made without departing from the scope of the invention as defined by the appended claims.