KR20170104981A - Common mode filter and method of manufacturing the same - Google Patents

Abstract

Provided is a common mode filter for improving inductance with a simple structure, and a manufacturing method thereof. The common mode filter comprises: a magnetic substrate; an insulating layer provided in an upper part of the magnetic substrate and having a coil electrode formed therein; an opening penetrating the center of the insulating layer; and a magnetic composite formed inside the opening, wherein a side wall of the opening is inclined at a predetermined angle.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a common mode filter,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a common mode filter, and more particularly, to a common mode filter having a means for increasing an inductance and a method of manufacturing the same.

As technology develops, electronic devices such as mobile phones, home appliances, PCs, PDAs, and LCDs are changing from analog to digital, and the speed is increasing due to an increase in the amount of data to be processed. As a result, USB 2.0, USB 3.0 and high-definition multimedia interface (HDMI) have been widely used as high-speed signal transmission interfaces and are used in many digital devices such as personal computers and digital high-definition televisions.

These interfaces employ differential signaling systems that transmit differential signals (differential mode signals) using a pair of signal lines differently than single-ended transmission systems that have been used for a long time. However, the digitized and accelerated electronic devices are sensitive to external stimuli. That is, when a small abnormal voltage from the outside and high frequency noise flow into the internal circuit of the electronic device, the circuit may be broken or the signal may be distorted.

At this time, the cause of the abnormal voltage and noise that cause circuit breakage and signal distortion of the electronic device may include lightning, electrostatic discharge charged to the human body, switching voltage generated in the circuit, power supply noise included in the power supply voltage, unnecessary electromagnetic signal And electromagnetic noise. In order to prevent circuit breakage or signal distortion of the electronic device, a filter is provided to prevent an abnormal voltage and high frequency noise from flowing into the circuit.

Generally, a common mode filter is used to eliminate common mode noise in high-speed differential signal lines and the like. Common-mode noise is the noise that originates in the differential signal line, and the common-mode filter removes noise that can not be eliminated by existing EMI filters. The common mode filter contributes to improvement of EMC characteristics of home appliances and the like or improvement of antenna characteristics of cellular phones and the like.

With reference to Japanese Patent Application Laid-Open No. 2001-015494, a conventional common mode filter has a structure in which magnetic members are provided on the upper and lower portions of a pair of first and second conductor coils surrounded by insulating resin.

In this structure, a magnetic flux is formed around the conductor coil when a current flows to the conductor coil through the external electrode terminal. In order to increase the electromagnetic coupling of the first and second conductor coils, Efforts have been made to improve the characteristics of the common mode filter, such as reducing the interval between the conductor coils and increasing the number of turns of the conductor coil in order to realize a high inductance (H).

However, this technique has a limitation in space due to the slimming and miniaturization of the device, and a complicated process for realizing this is complicated and sufficient characteristic improvement effect is not obtained compared with the complexity of the process. Therefore, And the like.

Japanese Patent Application Laid-Open Publication No. 2012-015494

The present invention provides a common mode filter capable of increasing the inductance by smoothly flowing a current through a magnetic line with a simpler structure without any additional process, and a manufacturing method thereof, thereby improving productivity and manufacturing cost of the product.

According to an aspect of the present invention, there is provided a magnetic substrate comprising: a magnetic substrate; An insulating layer provided on the magnetic substrate and having a coil electrode formed therein; An opening penetrating the center of the insulating layer; And a magnetic composite formed within the opening, the side wall of the opening providing a common mode filter inclined at a predetermined angle.

Further, the ratio of the bottom surface width w1 of the opening to the common mode filter element width w2 is 0.01: 1 to 0.2: 1.

The angle? Between the side wall of the opening and the horizontal line is greater than 45 degrees and less than 90 degrees.

The magnetic composite further includes a common mode filter including a soft magnetic metal and a ferrite as a main component.

In addition, the cross-section of the magnetic composite provides an elliptical or quadrangular, common mode filter.

In addition, the coil electrode is constituted by a primary coil electrode and a secondary coil electrode which form electromagnetic coupling, and provides a common mode filter.

And a magnetic composite formed between the outer electrode and the outer electrode, the outer electrode being formed on the upper surface of the insulating layer and connected to both ends of the coil electrode, respectively.

According to an aspect of the present invention, there is provided a method of manufacturing a magnetic memory device, comprising: forming a coil conductor and an insulation resin covering the coil conductor on one surface of a magnetic substrate, thereby forming an insulation layer surrounding the coil electrode; Firing the insulating layer; Forming an opening through the center of the insulating layer; And forming a magnetic composite within the opening, wherein the side wall of the opening is machined to be inclined at a predetermined angle.

Further, the processing of the openings provides a common mode filter manufacturing method using a laser technique.

Also, the magnetic composite is formed by filling a magnetic paste in which a soft magnetic metal powder and a ferrite powder are mixed as main components into the opening, and then curing the mixture, followed by curing.

In addition, an outer electrode, which is connected to both ends of the coil electrode, is formed on the upper surface of the insulating layer by plating to a predetermined thickness, and a soft magnetic metal powder and a ferrite powder are mixed as a main component between the outer electrodes including the opening. And then curing the filled magnetic paste.

According to the common mode filter of the present invention, it is possible to increase the inductance of the common mode filter through a simpler process without any additional process, thereby increasing the product productivity and reducing the manufacturing cost.

1 is an external perspective view of a common mode filter according to the present invention;
2 is a sectional view taken along line I-I '
Figure 3 is an internal top view of a common mode filter according to the present invention;
Fig. 4 is an internal plan view for explaining another form of the coil electrode included in the present invention. Fig.
5 is a cross-sectional view illustrating a case where the angle between the side wall of the opening and the horizontal line is 60 degrees
6 is a cross-sectional view illustrating a case where the angle between the side wall of the opening and the horizontal line is 45 degrees
FIGS. 7 to 10 are schematic diagrams sequentially illustrating a common mode filter manufacturing method according to the present invention.

The advantages and features of the present invention and the techniques for achieving them will be apparent from the following detailed description taken in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The present embodiments are provided so that the disclosure of the present invention is not only limited thereto, but also may enable others skilled in the art to fully understand the scope of the invention.

The terms used herein are intended to illustrate the embodiments and are not intended to limit the invention. In this specification, the singular forms include plural forms unless otherwise specified in the text. It is to be understood that the terms 'comprise', and / or 'comprising' as used herein may be used to refer to the presence or absence of one or more other components, steps, operations, and / Or additions.

FIG. 1 is an external perspective view of a common mode filter according to the present invention, and FIG. 2 is a sectional view taken along line I-I 'of FIG. In addition, the components of the drawings are not necessarily drawn to scale; for example, the dimensions of some of the components of the drawings may be exaggerated relative to other components to facilitate understanding of the present invention. In the meantime, for simplicity and clarity of illustration, the drawings illustrate the general construction and the detailed description of known features and techniques may be omitted so as to avoid unnecessarily obscuring the discussion of the described embodiments of the invention.

1 and 2, the common mode filter 100 of the present invention includes a magnetic substrate 110, an insulating layer 130 formed on the magnetic substrate 110 and having a coil electrode 120 formed therein, . ≪ / RTI >

The magnetic substrate 110 is made of Ni-Zn, Mn-Zn, Ni-Zn, Ni-Zn-Mg, and Mn-Zn alloys, which have high electrical resistance and small magnetic loss, Mg-Zn ferrite, or a mixture thereof, and forms a space for forming a magnetic path.

The coil electrode 120 is a conductor plated with a spiral on the same plane. The coil electrode 120 includes a primary coil electrode 121 that is electromagnetically coupled with an insulating resin, which is a constituent material of the insulating layer 130, And a secondary coil electrode (122). Alternatively, the primary coil electrode 121 and the secondary coil electrode 122 may be spaced apart from each other, or the primary coil electrode 121 and the secondary coil electrode 122 may be simultaneously and simultaneously plated on the same plane .

3, the coil electrode 120 is formed on the outer surface of the insulating layer 130 when viewed from the top, and the insulating layer 130 is formed on the outer surface of the insulating layer 130, An opening 151 is formed through the through hole 130 and the magnetic composite body 150 may be formed therein. That is, the coil electrode 120 is formed around the magnetic composite body 150 so as to be wound around the coil body.

The coil electrode 120 may be wound in an elliptical shape as shown in FIG. 3, or may be wound in a polygonal shape such as a rectangle as shown in FIG. 4. Corresponding to this, the cross section of the magnetic composite body 150 may also be an oval Or may be a rectangle as shown in FIG.

The common mode filter 100 of the present invention may further include an external electrode 140 formed on the insulating layer 130 and connected to an end of the coil electrode 120 through a connection terminal 141 And the magnetic composite body 160 may be formed between the external electrodes 140. The magnetic composite 160 between the magnetic composite 150 and the external electrode 140 in the opening 151 may be integrally formed.

The magnetic flux generated from the coil electrode 120 is magnetically coupled to the magnetic composite body 160 between the magnetic substrate 110 and the external electrode 140 and the magnetic composite body 150 inside the opening 151, The inductance can be greatly improved. As described above, the present invention resides in the magnetic composite body 150 formed inside the opening 151, and unless otherwise stated, the term magnetic composite body refers to a magnetic composite body formed inside the opening 151 150).

The width w1 of the bottom surface of the opening 151 and the width w2 of the chip device may be in a range of 0.01: 1 to 0.2: 1 .

The ratio is calculated in consideration of both the inductance due to the number of coil turns of the coil electrode 120 and the effect of increasing the inductance by the magnetic composite body 150. When the width w1 of the bottom surface of the opening 151 is too large If the ratio is less than the above ratio, it is difficult to form an opening, so that the inducing effect of the magnetic composite material 150 is not exhibited. Conversely, when the width w1 of the bottom surface of the opening 151 is too large, the maximum inductance can not be obtained due to a decrease in the number of coil turns of the coil electrode 120.

However, if the chip size is further reduced or the number of coil turns can be plated within a limited space due to development of the plating process technology, the ratio may be changed will be.

On the other hand, as the angle? Between the sidewall of the opening 151 and the horizontal line is smaller, the filling volume of the magnetic composite body 150 increases and a high inductance can be realized. The conductor of the coil electrode 120 on the inner side is exposed to the outside and the exposed conductor is removed so that the inductance is lowered due to the decrease in the number of coil turns of the coil electrode 120.

Table 1 below is a table for measuring the inductance according to the angle? Between the side wall of the opening 151 and the horizontal line. Referring to Table 1, the smaller the angle? It can be seen that the inductance increases due to the increase of the filling volume of the magnetic composite material 150.

It should be noted that, as in the example of FIG. 5, even if the angle? Is 60 degrees and the number of coil turns of the first coil electrode 121 in the upper layer is reduced by one turn due to the inclination, The drop in inductance is not large compared to the case of 70 degrees without reduction of the inductance. This means that the magnetic composite body 150 sufficiently cancels the inductance lost due to the decrease of the number of coil turns of the coil electrode 120 by one turn. This offset effect causes the number of coil turns to decrease by one turn Which is equal to or greater than 45 degrees but less than 60 degrees.

6, when the angle? Is 45 degrees, the number of coil turns of the coil electrode 120, which is reduced due to the inclination of the coil electrode 120 as the tangent becomes 1, Two turns of the coil turns of the first coil electrode 121 and one turn of the coil turns of the second coil electrode 122 located in the lower layer, resulting in a sudden drop in inductance. Therefore, the angle? Between the side wall of the opening 151 and the horizontal line is preferably set in a range of more than 45 degrees but less than 90 degrees.

Now, a method of manufacturing the common mode filter 100 of the present invention will be described.

7 to 10 are views illustrating a method of fabricating the common mode filter 100 according to an embodiment of the present invention. Referring to FIG. 7, A coil conductor and an insulating resin covering the coil conductor are repeatedly formed to form an insulating layer 130 surrounding the coil electrode 120. [

The insulating resin may be applied using common techniques such as a dip coating method or a spin coating method, and the insulating resin of each layer is then integrated through a curing process.

The coil electrode 120 may be formed using a known technique such as a subtracting method, an additive method, or a semi-additive method. At this time, the connection terminals 141 for electrical connection with the external electrodes are preferably plated together.

When the uppermost insulating resin is coated, the insulating layer 130 is heat-treated under a predetermined condition to cure the insulating layer 130. At this time, depending on the heat treatment conditions, the inclination angle? Of the opening 151 formed in the subsequent step can be determined.

When the heat treatment process is completed, an opening 151 passing through the insulating layer 130 is formed in the center of the insulating layer 130 as shown in FIG. At this time, since the insulating layer 130 is photosensitive, the opening 151 can be patterned as much as necessary by irradiating ultraviolet rays (UV). Or by a laser technique such as an Eximer laser, a YAG laser, or a CO ₂ laser.

9, the external electrode 140 connected to the end of the coil electrode 120 is plated to a predetermined thickness on the upper surface of the insulating layer 130, and finally, the opening 151 The common mode filter 100 of the present invention can be finally completed by filling and hardening the magnetic paste between the external electrodes 140 including the internal electrodes 140a and 140b.

The magnetic paste is a slurry-type magnetic material in which a soft magnetic metal powder and a ferrite powder are mixed as main components. When the magnetic paste is injected into the gap between the outer electrodes 140, And when the filling up to the height of the external electrode 140 is completed, it is sintered and cured. Accordingly, the magnetic composite body 160 between the external electrodes 140 and the magnetic composite body 150 inside the opening 151 are integrally formed.

The foregoing detailed description is illustrative of the present invention. It is also to be understood that the foregoing is illustrative and explanatory of preferred embodiments of the invention only, and that the invention may be used in various other combinations, modifications and environments. That is, it is possible to make changes or modifications within the scope of the concept of the invention disclosed in this specification, the disclosure and the equivalents of the disclosure and / or the scope of the art or knowledge of the present invention. The foregoing embodiments are intended to illustrate the best mode contemplated for carrying out the invention and are not intended to limit the scope of the present invention to other modes of operation known in the art for utilizing other inventions such as the present invention, Various changes are possible. Accordingly, the foregoing description of the invention is not intended to limit the invention to the precise embodiments disclosed. It is also to be understood that the appended claims are intended to cover such other embodiments.

100: common mode filter 110: magnetic substrate
120: coil electrode 130: insulating layer
140: external electrode 150, 160: magnetic complex
151: opening

Claims (7)

A magnetic substrate;
An insulating layer provided on the magnetic substrate and including a first coil electrode and a second coil electrode disposed under the first coil electrode;
An opening passing through the central portion of the insulating layer and having a side wall inclined at a predetermined angle in such a manner that the width thereof becomes narrower from the first coil electrode toward the second coil electrode; And
And a magnetic composite formed inside the opening,
Wherein the first coil electrode has one turn less than the second coil electrode.
The method according to claim 1,
Wherein a ratio of a bottom surface width (w1) of the opening portion to a common mode filter element width (w2) is 0.01: 1 to 0.2:
Common mode filter.
The method according to claim 1,
Wherein an angle &thetas; between the side wall of the opening and the horizontal line is greater than 45 degrees and less than 90 degrees,
Common mode filter.
The method according to claim 1,
Wherein the magnetic composite comprises a soft magnetic metal and a ferrite as a main component,
Common mode filter.
The method according to claim 1,
Wherein the cross-section of the magnetic composite is elliptical or rectangular,
Common mode filter.
The method according to claim 1,
An outer electrode formed on an upper surface of the insulating layer and connected to both ends of the first and second coil electrodes, and a magnetic composite formed between the outer electrode and the outer electrode,
Common mode filter.
The method according to claim 6,
Wherein the magnetic composite body formed between the magnetic composite body and the external electrode formed in the opening portion is integrally formed,
Common mode filter.

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