Coil electronic component

Abstract

A coil electronic component includes a body including a plurality of insulating layers and coil patterns disposed on the insulating layers, and external electrodes formed on an external surface of the body and connected to the coil patterns. The plurality of insulating layers include a NiCuZn based ferrite, and the NiCuZn based ferrite has a content of Ni within a range from 5 to 15%, a content of Cu within a range from 5 to 10%, and a content of Zn within a range from 28 to 35% based on a mole ratio.

Claims

1. A coil electronic component comprising: a body including a plurality of insulating layers and coil patterns disposed on the insulating layers; and external electrodes formed on an external surface of the body and connected to the coil patterns, wherein the plurality of insulating layers include a NiCuZn based ferrite, the NiCuZn based ferrite has a content of Ni within a range from 5 to 15%, a content of Cu within a range from 5 to 10%, and a content of Zn within a range from 28 to 35%, based on a mole ratio of the NiCuZn based ferrite, an average size of crystal grains of the NiCuZn based ferrite is 10 m or more and 20 m or less, and the NiCuZn based ferrite does not contain Bi.

2. The coil electronic component of claim 1, wherein the NiCuZn based ferrite has a permeability of 1500 or more.

3. The coil electronic component of claim 1, wherein the NiCuZn based ferrite is sintered in an atmosphere having an oxygen partial pressure within a range from 1% to 5%.

4. The coil electronic component of claim 1, wherein a content of iron (Fe) in the NiCuZn based ferrite is within a range from 45% to 55%, based on the mole ratio of the NiCuZn based ferrite.

5. The coil electronic component of claim 1, wherein the NiCuZn based ferrite does not contain a sintering preparation component.

6. The coil electronic component of claim 1, wherein the NiCuZn based ferrite does not contain V or Si.

7. The coil electronic component of claim 1, wherein the plurality of insulating layers and the coil patterns are stacked.

8. The coil electronic component of claim 7, further comprising a plurality of conductive vias electrically connecting the coil patterns to each other.

9. The coil electronic component of claim 1, wherein the coil patterns include silver (Ag).

Description

BRIEF DESCRIPTION OF DRAWINGS

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

(2) FIG. 1 is a perspective view schematically illustrating a coil electronic component according to an exemplary embodiment in the present disclosure, in which an internal coil pattern is exposed;

(3) FIG. 2 illustrates forms of the coil patterns in the coil electronic component of FIG. 1 according to an exemplary embodiment in the present disclosure;

(4) FIG. 3 schematically illustrates a form of crystal grains that an insulating layer employed in the coil electronic component of FIG. 1 may have;

(5) FIG. 4 is a view illustrating a sintering behavior of a NiCuZn ferrite in low oxygen atmosphere conditions; and

(6) FIGS. 5 and 6 illustrate results obtained by measuring inductance and RX cross frequency characteristics of the NiCuZn based ferrite which is sintered at different oxygen partial pressures.

DETAILED DESCRIPTION

(7) Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

(8) FIG. 1 is a perspective view schematically illustrating a coil electronic component according to an exemplary embodiment in the present disclosure, in which an internal coil pattern is exposed. FIG. 2 illustrates forms of the coil patterns in the coil electronic component of FIG. 1 according to an exemplary embodiment in the present disclosure. In addition, FIG. 3 schematically illustrates a form of crystal grains that an insulating layer employed in the coil electronic component of FIG. 1 may have.

(9) Referring to FIGS. 1 and 2, a coil electronic component 100 according to the present exemplary embodiment may have a structure including a body 110, a coil part 120, and external electrodes 130. A plurality of insulating layers 111 configuring the body 110 may include a NiCuZn based ferrite. Hereinafter, the respective components configuring the coil electronic component 100 will be described.

(10) The body 110 may include the plurality of insulating layers 111 and the coil part 120 disposed on the plurality of insulating layers 111. The plurality of insulating layers 111 configuring the body 110 may be a sintered body of the NiCuZn based ferrite. The coil part 120 may include a plurality of coil patterns 121 which are stacked, and the coil patterns 121 may forma form of a spiral coil according to a stacked direction. In this case, the coil patterns 121 formed at different levels may be connected to each other by conductive vias 124. In addition, the coil part 120 may include leading parts 123 which are led externally from the body 110 in order to connect the coil patterns 121 disposed on the uppermost and lowest portions of the insulating layers to the external electrodes 130. The leading parts 123 may be formed by using the same material and the same process as the coil patterns 121.

(11) The coil patterns 121 may be formed by printing a conductive paste including a conductive metal on the plurality of insulating layers 111 at a predetermined thickness. The conductive metal forming the coil patterns 121 is not particularly limited as long as it is a metal having excellent electrical conductivity. For example, the conductive metal may be one of silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni), titanium (Ti), gold (Au), copper (Cu), platinum (Pt), and the like, or a mixture thereof. In a case in which the coil pattern 121 includes silver (Ag) having a low melting point, since a sintering temperature of the NiCuZn based ferrite included in the insulating layer 111 needs to be lowered, there is a limitation to increase permeability of the NiCuZn based ferrite. According to the present exemplary embodiment, even in a case in which the coil patterns 121 including silver (Ag) are sintered at a low temperature, a high level of permeability may be obtained by adjusting a composition and a size of the crystal grain of the NiCuZn based ferrite.

(12) The external electrodes 130 may be formed on an external surface of the body 110 to be connected to the coil patterns 121, and may be connected to the leading parts 123 as illustrated in FIG. 1. The external electrodes 130 may be formed of a metal having excellent electrical conductivity, for example, one of nickel (Ni), copper (Cu), tin (Sn), or silver (Ag), or an alloy thereof.

(13) As described above, according to the present exemplary embodiment, the insulating layer 111 may include the NiCuZn based ferrite. According to the research of the inventors, high permeability of about 1500 or more may be implemented while not increasing the sintering temperature by adjusting the size of the crystal grain in the NiCuZn based ferrite of a certain composition range to be relatively large. The NiCuZn based ferrite may have a content of Ni within a range from 5 to 15%, a content of Cu within a range from 5 to 10%, and a content of Zn within a range from 28 to 35% based on a mole ratio of the NiCuZn based ferrite. When the NiCuZn based ferrite has the above-mentioned composition range, it was confirmed that a crystal growth of the ferrite is accelerated in a low oxygen partial pressure condition. In addition, iron (Fe), which is a main component in the NiCuZn based ferrite, may have a content within a range from 45 to 55% based on a mole ratio of the NiCuZn based ferrite. In a case in which the composition range and the sintering condition proposed by the present exemplary embodiment are satisfied, even though a sintering preparation component is not separately added, a crystal grain g of the ferrite may be formed to be large due to excellent sinterability. Accordingly, the NiCuZn based ferrite may not contain a sintering preparation component. Representative examples of the sintering preparation component may include V, Bi, and Si components, which are generally added in the form of V.sub.2O.sub.5, Bi.sub.2O.sub.3, and SiO.sub.2, respectively. However, when the sintering preparation component is added, permeability may be decreased. In consideration of this, the sintering preparation component is not used in the NiCuZn based ferrite according to the present exemplary embodiment. For example, the NiCuZn based ferrite according to the present exemplary embodiment may not contain V, Bi or Si.

(14) Referring to FIG. 3, as the crystal growth is accelerated, the crystal grain g of the NiCuZn based ferrite may be formed to be larger than the conventional crystal grain. Specifically, an average size of the crystal grains may be 10 m or more. More specifically, the average size of the crystal grains of the NiCuZn based ferrite may be within a range from 10 m or more to 20 m or less. Such an average size of the crystal grains is significantly larger than a size of the crystal grain of the conventional NiCuZn based ferrite, which is generally about 1 to 2 m, and about 4 to 5 m even when a liquid sintering preparation component is added. Here, the size of the crystal grain may be defined as an equivalent circle diameter obtained by measuring an area of a separate crystal grain and converting the area into a diameter of a circle having the same area.

(15) When the NiCuZn based ferrite having the composition range described above is sintered in a low oxygen partial pressure condition, the crystal growth thereof may be accelerated and the size of the crystal grain thereof may be increased. This will be described with reference to FIGS. 4 through 6. FIG. 4 is a view illustrating a sintering behavior of a NiCuZn based ferrite in low oxygen atmosphere conditions. FIGS. 5 and 6 illustrate results obtained by measuring inductance and RX cross frequency characteristics of the NiCuZn based ferrite which is sintered at different oxygen partial pressures. Here, the RX cross frequency is a frequency at which resistance R and inductance X of the NiCuZn based ferrite are equal to each other and generally shows a tendency to be inversely proportional to permeability of the material.

(16) Referring to FIG. 4, in a case in which the NiCuZn based ferrite is sintered in a low oxygen partial pressure condition, voids V may occur at positions of oxygen, which is a negative ion B, and a positive ion A such as Zn, Ni, Cu, or the like may be substituted for the voids. Accordingly, diffusion driving force of ions is increased in the low oxygen partial pressure, such that high sinterability may be secured at a low temperature. In addition, referring to graphs of FIGS. 5 and 6, it may be confirmed that inductance and permeability are increased in the NiCuZn based ferrite which is sintered in an atmosphere having an oxygen partial pressure within a range from about 1% to 5%. Unlike the present exemplary embodiment, when the NiCuZn based ferrite having the same composition is sintered (about 920 C.) in atmosphere, the average size of the crystal grains is a level of 0.5 to 1.5 m, and a desired level of permeability may not be obtained.

(17) As described above, when a multilayer inductor is implemented using the NiCuZn based ferrite having the composition range and the average size of the crystal grains proposed by the exemplary embodiment described above, since sinterability may be improved, co-firing with the metal forming the coil patterns may be possible and a high level of permeability may be obtained. Such a multilayer inductor may be effectively used as a component for removing low frequency noise of 1 MHz or less and may be applied to various applications requiring high permeability characteristics.

(18) As set forth above, according to the exemplary embodiments in the present disclosure, when the coil electronic component is used, a high level of permeability may be implemented, and the low frequency noise characteristic and the like may be thus improved.

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