JP2004260008A - Common mode choke coil, its manufacturing method and common mode choke coil array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain magnetic coupling substantially similar to that of a closed circuit and a high common impedance while enhancing adhesion of a magnetic substrate. <P>SOLUTION: An insulation layer and a coil pattern including coil conductor layers 5 and 7 are formed alternately on a first magnetic substrate 1, central region of each insulation layer surrounded by the coil pattern and the insulation layer part in the outer circumferential region of the coil pattern are removed, resin (magnetic layer 11) containing magnetic powder is provided on the top insulation layer and also buried in the part from where the insulation layer is removed, and then a second magnetic substrate 13 is bonded to the flattened surface of the resin containing magnetic powder through an adhesive layer 12. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a common mode choke coil, a method for manufacturing the same, and a common mode choke coil array, and more particularly to a filter used for suppressing a common mode current that causes electromagnetic interference which is a problem in a balanced transmission system, and a method for manufacturing the filter. About the method.
[0002]
[Prior art]
Conventionally, a multilayer type is known as a chip-type common mode choke coil. This component has a structure in which a coil conductor pattern is formed on the surface of a magnetic material sheet such as ferrite to form a first coil, and a first coil magnetic sheet and a similar second coil magnetic sheet are alternately laminated.
[0003]
Also, a common mode choke coil disclosed in Patent Document 1 below is known as one using a thin film method. In this part, a lead electrode is formed on a magnetic substrate by a thin film method, and then an insulating layer, a first coil conductor, an insulating layer, a second coil conductor, and an insulating layer are sequentially formed by a thin film method, and the magnetic layer is formed from the upper surface. The structure is sandwiched between substrates.
[0004]
In the case of a common mode choke coil formed by a thin film method, as described in Patent Document 2 below, the center part and the outer peripheral part of the insulating layer of the thin film method are etched to improve the degree of magnetic coupling between the coils and increase the common impedance. (Development), and the upper magnetic substrate is bonded with a resin obtained by mixing magnetic powder with an insulating material to form a closed magnetic circuit structure.
[0005]
[Patent Document 1] JP-A-8-203737 [Patent Document 2] JP-A-11-54326
[Problems to be solved by the invention]
In the above-described conventional laminated type, a magnetic sheet exists between the first coil and the second coil conductor, and when used as a common mode choke coil, the magnetic coupling between the two coils is reduced, causing a problem in characteristics. .
[0007]
The common mode choke coil according to the thin film method disclosed in Patent Document 1 has a structure in which the first and second coil conductors are sandwiched between upper and lower magnetic substrates and does not have a closed magnetic circuit structure. There is a problem in point (it is difficult to increase the degree of magnetic coupling and common impedance).
[0008]
Although the above-mentioned problem can be solved by the thin film method of Patent Document 2 because a closed magnetic circuit structure is formed, a resin containing magnetic powder has low adhesiveness, and a problem occurs in the adhesiveness of the magnetic substrate.
[0009]
As a countermeasure, it is possible to apply a magnetic powder-containing resin to the magnetic layer bonding side of the insulating layer containing the coil conductor and then cure it, and then bond the magnetic substrate with an adhesive. The resin containing magnetic powder buried in the etched portion of the insulating layer (the portion where the center and outer peripheral portions of the insulating layer were etched to form a closed magnetic circuit structure) shrinks, and only the upper adhesive layer (non-magnetic) However, the effect of increasing the common impedance cannot be obtained much.
[0010]
In view of the above, the present invention provides a common mode choke coil capable of improving the adhesiveness of a magnetic substrate, obtaining substantially the same degree of magnetic coupling as a closed magnetic circuit, and obtaining a high common impedance, and manufacturing the same. It is an object to provide a method as well as a common mode choke coil array.
[0011]
Other objects and novel features of the present invention will be clarified in embodiments described later.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a common mode choke coil according to the invention of claim 1 of the present application is configured such that insulating layers and coil patterns are alternately formed on a first magnetic substrate, and the coil pattern of each insulating layer is formed on the first magnetic substrate. The insulating layer portion in the central region and the outer peripheral region of the coil pattern is removed, and a resin containing magnetic powder is provided on the uppermost insulating layer, and the resin containing magnetic powder is buried in the removed portion of the insulating layer. A second magnetic substrate is bonded to the flattened surface of the magnetic powder-containing resin via an adhesive layer.
[0013]
A common mode choke coil array according to a second aspect of the present invention includes a plurality of the common mode choke coils according to the first aspect.
[0014]
A method for manufacturing a common mode choke coil according to the invention of claim 3 of the present application includes a film forming step of alternately forming an insulating layer and a coil pattern on a first magnetic substrate;
An etching step of removing an insulating layer portion of a central region and an outer peripheral region of the coil pattern surrounded by the coil pattern of each insulating layer;
A coating step of applying the magnetic powder-containing resin on the uppermost insulating layer and embedding and coating the magnetic powder-containing resin also on the removed portion of the insulating layer;
A polishing step of polishing and flattening the resin surface containing the magnetic powder after curing the resin containing the magnetic powder,
And a bonding step of bonding a second magnetic substrate to the flattened surface of the resin containing the magnetic powder via an adhesive.
[0015]
The method of manufacturing a common mode choke coil according to the invention of claim 4 of the present application is characterized in that, in claim 3, the magnetic powder-containing resin is applied by a printing method.
[0016]
In the method of manufacturing a common mode choke coil according to the invention of claim 5 of the present application, the thickness of the magnetic powder-containing resin provided in the coating step is determined by setting the thickness of the concave step of the removed portion of the insulating layer to 1. It is characterized in that it is 5 times or more.
[0017]
The method of manufacturing a common mode choke coil according to the invention of claim 6 of the present application is characterized in that, in claim 3, 4, or 5, the etching step is performed every time one insulating layer is formed.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a common mode choke coil, a method of manufacturing the same, and a common mode choke coil array according to the present invention will be described with reference to the drawings.
[0019]
1 and 2 show an embodiment of the present invention. FIG. 1 is an exploded perspective view of a chip type common mode choke coil, and FIG. 2 is an explanatory view showing a manufacturing process. At the time of actual production, a plurality of components are produced on a substrate at the same time, but in this embodiment, description will be made for one element.
[0020]
As shown in these figures, the chip-type common mode choke coil has an insulating layer 2, a first lead electrode layer 3, an insulating layer 4, a first coil conductor layer (a spiral coil) on a main surface of a first magnetic substrate 1. Conductor pattern) 5, insulating layer 6, second coil conductor layer (spiral coil conductor pattern) 7, insulating layer 8, second extraction electrode layer 9, insulating layer 10, magnetic layer 11, adhesive layer 12, and second magnetic substrate The components are laminated and integrated in the order of 13.
[0021]
At this time, the first extraction electrode layer 3 and the first coil conductor layer 5, and the second extraction electrode layer 9 and the second coil conductor layer 7 are respectively electrically connected via through holes. One end of each lead electrode layer and one end of each coil conductor layer are respectively connected to external electrodes (formed on the outer peripheral surface of the chip).
[0022]
The magnetic layer 11 is formed by applying and curing a resin containing a magnetic powder. After curing, the surface is reduced by polishing and the second magnetic substrate 13 is bonded to the flattened surface via the adhesive layer 12. Become
[0023]
The magnetic substrates 1 and 13 are made of sintered ferrite, composite ferrite or the like, and the insulating layers 2, 4, 6, 8 and 10 are made of a material having excellent insulation properties such as polyimide resin and epoxy resin and having good workability. The magnetic powder-containing resin constituting the layer 11 is obtained by mixing magnetic powder such as ferrite into epoxy resin or the like.
[0024]
The procedure for manufacturing the chip-type common mode choke coil is as follows. However, this is the case where the extraction electrode layers 3 and 9 and the first and second coil conductor layers 5 and 7 which are spiral coil conductor patterns are formed by a vacuum film forming method (evaporation, sputtering, etc.) or plating.
[0025]
An insulating layer made of an insulating resin is formed on a magnetic substrate. As a forming method, a spin coating method, a dip method, a spray method, and a printing method are employed. Thereafter, the insulating layer 2 is etched (developed) to remove a central region surrounded by the spiral coil conductor pattern and an outer peripheral region of the spiral coil conductor pattern.
[0026]
A metal film is formed on the insulating layer 2 by using a vacuum film forming method or a plating method. The metal used is preferably Cu, Al or the like from the viewpoint of conductivity and workability. After that, a pattern is formed to form the extraction electrode layer 3. The patterning method is performed by an etching method using photolithography, an additive method (plating) using photolithography, or the like.
[0027]
Next, the method of forming the insulating layer 4 made of insulating resin is the same as that of the insulating layer 2. At this time, a contact hole for connecting the extraction electrode layer 3 and the coil conductor layer 5 is formed simultaneously with the etching of the center and outer peripheral regions of the coil conductor pattern.
[0028]
Next, the first coil conductor layer 5 which is a spiral coil conductor pattern is formed. The construction method is the same as that of the extraction electrode layer 3.
[0029]
Next, an insulating layer 6 made of an insulating resin is formed. The construction method is the same as that of the insulating layer 2.
[0030]
In the same manner, a second coil conductor layer 7 serving as a spiral coil conductor pattern, an insulating layer 8 (insulating resin), a lead electrode layer 9, and an insulating layer 10 (insulating resin) are sequentially formed.
[0031]
As described above, a film forming step of alternately forming the insulating layer made of the insulating resin and the conductor layer including the spiral coil conductor pattern on the first magnetic substrate 1, and the center of each insulation layer surrounded by the coil conductor pattern By performing an etching step of removing the insulating layer portion in the region and the outer peripheral region of the coil conductor pattern, a laminated body 20 having the coil conductor pattern embedded on the first magnetic substrate 1 is obtained as shown in FIG. As a result, a resin removing portion 21 (recess) and a resin removing portion 22 (notch) from which the insulating layer has been removed are formed in the central region and the peripheral region of the laminate 20.
[0032]
Next, from the upper surface of the insulating layer 10 (the upper surface of the laminated body 20 in FIG. 2), a resin containing magnetic powder (cured to become a magnetic layer) 11 is printed in the application step of FIG. . At the time of printing application, the resin 11 containing the magnetic powder is applied so as to be embedded in the resin removing portions 21 and 22. However, when the resin is cured, the resin shrinks and the surface of the resin containing the magnetic powder generates irregularities (the resin removing portions 21 and 22 have different shapes). The position has a recess). In order to minimize the occurrence of the unevenness, the thickness t of the magnetic powder-containing resin 11 provided in the coating step is preferably at least 1.5 times the concave step d of the resin removing portions 21 and 22.
[0033]
Next, as shown in FIG. 2B, the upper surface of the magnetic powder-containing resin 11 is polished to the height of the alternate long and short dash line P to perform a flattening step (reduce uneven portions).
[0034]
Next, in the bonding step shown in FIG. 2C, an adhesive is applied on the magnetic layer 11 after polishing and flattening the entire upper surface of the cured magnetic powder-containing resin to provide an adhesive layer 12, thereby forming a second magnetic substrate. 13 is pasted.
[0035]
Although the above description has been made with reference to the drawing for one element, actually, a plurality of elements are simultaneously manufactured on the substrate. After the device manufactured on this substrate is cut into one-element-shaped chips, external electrodes are formed on the outer surfaces of the chips to complete a common mode choke coil.
[0036]
According to this embodiment, the following effects can be obtained.
[0037]
(1) The second magnetic substrate 13 can be securely bonded and held, and structural reliability can be ensured. Further, the second magnetic substrate 13 is adhered after the unevenness of the magnetic layer 11 in which the resin containing the magnetic powder is hardened is flattened, so that a magnetic coupling degree substantially equal to that of the closed magnetic circuit and a high common impedance can be obtained. Is possible.
[0038]
(2) By setting the thickness t of the magnetic powder-containing resin provided in the coating step to be 1.5 times or more the concave step d of the resin removing portions 21 and 22, unevenness of the magnetic layer 11 in which the magnetic powder-containing resin is cured is generated. And the amount of polishing in the flattening step can be reduced.
[0039]
FIG. 3 shows another embodiment of the present invention, in which a common mode choke coil array is manufactured. In this case, two configurations of the common mode choke coil of the embodiment are formed on the first magnetic substrate 1 side by side. The same reference numerals are given to the same or corresponding parts as in the above-described embodiment, and the description is omitted.
[0040]
Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims.
[0041]
【The invention's effect】
As described above, according to the present invention, while improving the adhesiveness of the magnetic substrate, a degree of magnetic coupling substantially similar to that of a closed magnetic circuit, and a common mode choke coil capable of obtaining a high common impedance, A common mode choke coil array can be realized.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an embodiment of the present invention when a common mode choke coil is configured.
FIG. 2 is an explanatory diagram showing a manufacturing process in the case of the embodiment.
FIG. 3 is an exploded perspective view of another embodiment of the present invention in which a common mode choke coil array is formed.
[Explanation of symbols]
1,13 Magnetic substrate 2,4,6,8,10 Insulating layer 3,9 Leader electrode layer 5,7 Coil conductor layer 11 Magnetic layer 12 Adhesive layer 20 Laminate 21,22 Resin removal section

Claims (6)

An insulating layer and a coil pattern are alternately formed on the first magnetic substrate, and an insulating layer portion in a central region surrounded by the coil pattern and an outer peripheral region of the coil pattern of each insulating layer is removed. A magnetic powder-containing resin is provided on the layer, and the magnetic powder-containing resin is also embedded in the removed portion of the insulating layer. A common mode choke coil characterized by being adhered. A common mode choke coil array including a plurality of the common mode choke coils according to claim 1. A film forming step of alternately forming an insulating layer and a coil pattern on the first magnetic substrate;
An etching step of removing an insulating layer portion of a central region and an outer peripheral region of the coil pattern surrounded by the coil pattern of each insulating layer;
A coating step of applying the magnetic powder-containing resin on the uppermost insulating layer and embedding and coating the magnetic powder-containing resin also on the removed portion of the insulating layer;
A polishing step of polishing and flattening the resin surface containing the magnetic powder after curing the resin containing the magnetic powder,
Bonding a second magnetic substrate to the flattened surface of the resin containing the magnetic powder via an adhesive. 4. The method for manufacturing a common mode choke coil according to claim 3, wherein the resin containing the magnetic powder is applied by a printing method. The method for manufacturing a common mode choke coil according to claim 3 or 4, wherein the thickness of the resin containing the magnetic powder provided in the applying step is at least 1.5 times the concave step of the removed portion of the insulating layer. 6. The method for manufacturing a common mode choke coil according to claim 3, wherein the etching step is performed every time one insulating layer is formed.

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