JPH06151181A - Series-coupled type lc composite element and manufacture thereof - Google Patents

Abstract

PURPOSE:To realize a series-coupled type LC composite element, which is made compact and thin, by bonding an inductor, which is manufactured by embedding a coil and electrodes, and a capacitor in a thin-film or sheet shape on the surface of a ferrite sheet. CONSTITUTION:A coil 5 and electrodes 6 and 6' are formed in recess parts, which are provided in the surface of a ferrite sheet 2 by a mechanical method. A ferrite sheet 14 having the same magnetic characteristic as the ferrite sheet 2 is stuck on the surface thereof, and an inductor is formed. A capacitor 9 is bonded on the rear surface of the ferrite sheet 2, on which the coil 5 and the electrodes 6 and 6' are provided. The capacitor 9 is formed of a dielectric film or sheet, and electrodes 11 and 11' are provided on both surfaces. The electrodes of the inductor and the capacitor 9 are coupled by way of a through hole 8, which is provided in the ferrite sheet 2, with a bonding agent 12. In this way, the structure is made simple, the compact and thin configuration can be achieved and the circuit can be made small.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a power supply circuit used in equipment for OA, AV, FA and the like, a filter for removing external noise generated in a digitized circuit, noise generated by a circuit element, and the like. In particular, the present invention relates to a series-coupling type LC composite element for the purpose of downsizing and thinning, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Noise generated in an electronic circuit includes noise coming from a power supply line, noise generated between a line and an earth, and noise generated in a circuit, particularly a switch element or a semiconductor element. There are external noises, etc., and noise filters having various structures are used as means for eliminating these noises. These noises were basically composed of a composite element in which an inductor made of a ferrite sintered body and a capacitor made of a dielectric were joined to each other, and had a large shape.

[0003]

With the miniaturization of electronic equipment systems, the density of circuits has increased, and there has been an increasing demand for miniaturization, thinning, and IC integration of electronic components suitable for high density. Investigations including density mounting are underway. Among electronic parts, the parts that are behind the miniaturization and thinning are parts (L) made of magnetic materials and capacitor parts (C).
Therefore, there is a strong demand for miniaturization and thinning of these.

It is an object of the present invention to provide a series-coupling type LC composite element and a method for manufacturing the same, which can meet such demands.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a coil is sandwiched between ferrite sheets, and a coil and an electrode-shaped concave pattern are formed in advance on one ferrite sheet surface. And an inductor (L) manufactured by embedding a thin film or a sheet-like capacitor (C) on the ferrite sheet surface.

[0006]

According to the present invention, a recessed pattern having the shape of a coil and an electrode is formed in an unfired state on a ferrite sheet produced by the doctor blade method, and a coil is made of a conductive material in the recess. An electrode is formed and a ferrite shield with the same characteristics is formed on the surface.
It is manufactured by directly joining an inductor formed by attaching a sheet and a capacitor formed of a thin film or a sheet on the side opposite to the surface on which the coil is formed. Therefore, it is possible to make the LC element significantly smaller and thinner than the conventional composite element formed by combining L and C.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) First, the series connection type L of the present invention.
A method of manufacturing the C composite element will be described.

As shown in FIG. 1, a paste prepared by kneading Ni--Zn ferrite fine powder and an organic binder is applied to the surface of the separating paper 3 by a jig 1 having a gap for controlling the film thickness. 20
It was applied to a thickness of 0 micron, dried by touching with a finger, and then the release paper was peeled off to leave unbaked Ni-Zn ferrite sheet.
2 (see FIG. 2) was produced.

FIG. 3 shows a smooth surface with a height of 20 μm.
A die having a spiral coil pattern 5 having a width of 30 μm, a pitch of 50 μm and a convex shape of electrode patterns 6 and 6 ′ provided at both ends of the coil is shown. FIG. 4 is a cross-sectional view showing the mold cut along the lines A and A ′ in FIG.

As shown in FIG. 5, the unsintered Ni—Zn ferrite 2 was sandwiched and pressed between the mold of FIG. 3 and a mold 7 having a smooth surface.

FIG. 6 shows an unbaked Ni-Zn ferrite sheet 2 having a concave pattern formed on the surface by transferring a pattern 5 of a mold. Reference numeral 8 is a sulfol provided on the ferrite sheet 2 of one of the electrode portions.

The unsintered ferrite sheet 2 thus prepared was heated in air to obtain a sintered ferrite sheet 2.

On the other hand, as shown in FIG. 7, a paste 10 prepared by kneading barium titanate-based fine powder and an organic binder is separated by a jig 1 having a gap for controlling the film thickness. Was coated on the surface of No. 10 in a thickness of 10 μm, dried by touch with the finger, the release paper 10 was peeled off, and baked in the air to prepare a capacitor sheet. Cu electrode films 11 and 11 'were formed on the upper and lower surfaces of this sheet by a sputtering method (see FIG. 8).

The capacitor sheet shown in FIG. 8 is bonded with a conductive adhesive 13 to the surface of the ferrite sheet 2 fired as described above opposite to the surface on which the concave pattern is formed (FIG. 9). reference). In addition, the conductive adhesive 12 was filled in the sulfol 8.

Next, a Cu film 15 was formed on the surface of the fired ferrite sheet 2 on which the concave shape was provided by a sputtering method (see FIG. 10).

Cu film 15 formed other than the concave pattern
Then, as shown in FIG. 11, the coil pattern 5 and the electrode patterns 6, 6'are removed by polishing, for example.

Series-coupled LC manufactured in this way
The composite element includes a coil electrode 6 and a capacitor electrode 11 '.
Are electrically joined with a conductive adhesive 12 through the sulfol 8. The size of the capacitor was 4 mm square.

Next, as shown in FIG. 12, a ferrite sheet 14 having the same magnetic characteristics as the ferrite sheet 2 and a thickness of 200 μm is joined with a non-conductive adhesive to form a magnetic material. Eliminates the leakage of magnetic flux to the outside. The L value obtained at this time was 12 microhenry at 5 MHz with 10 turns. C was 7 microfarads.

Example 2 The same series-coupling type LC composite device as in Example 1 was obtained by using Mn-Zn ferrite sheet instead of the Ni-Zn ferrite sheet of Example 1. The L value at this time was 8 microhenry at 5 MHz.

(Example 3) Instead of barium titanate of Example 1, a film of tantalum oxide and tantalum nitride was formed to a thickness of 1 micrometer by the reactive sputtering method, and the same series connection was performed. Type LC element. For example, in the case of a tantalum oxide film, the size was 4 microfarads and the size was 6 microfarads.

(Embodiment 4) In Embodiment 1, a barium titanate-based film having a 4 mm millimeter angle is plasma-C.
The thickness was set to 1 micron using the VD method. The value of C at this time was 18 microfarads.

[0023]

As is apparent from the above description,
According to the series-coupling type LC composite element and the method of manufacturing the same according to the present invention, the structure is simple, the size and the thickness can be reduced, and it is very useful for downsizing the circuit.

[Brief description of drawings]

FIG. 1 is a perspective view showing a method of forming a ferrite sheet on a release paper by a doctor blade method according to an embodiment of the present invention.

FIG. 2 is a ferrite sheet prepared in one embodiment of the present invention.
FIG.

FIG. 3 is a convex pattern for forming a coil and an electrode formed on the surface of a pressing die according to an embodiment of the present invention.
FIG.

FIG. 4 is a cross-sectional view of the mold taken along the lines A and A ′ of FIG. 3 according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a state where an unfired ferrite sheet is pressed using a mold in one example of the present invention.

FIG. 6 is a cross-sectional view showing a ferrite sheet to which a pattern on the surface of a mold is transferred according to an embodiment of the present invention.

FIG. 7 is a perspective view showing a method of forming a condenser sheet on a release paper by a doctor blade method according to an embodiment of the present invention.

FIG. 8 is an embodiment of the present invention in which a fired capacitor sheet is used.
It is sectional drawing which provided the electrode on both surfaces of the gutter.

FIG. 9 is a cross-sectional view showing a state in which a capacitor sheet is joined to a back surface of a ferrite sheet with a conductive adhesive and a sulfur is filled with the conductive adhesive in an embodiment of the present invention. Is.

FIG. 10 is a cross-sectional view showing a coil and an electrode conductive film formed on a ferrite sheet concave pattern surface in an embodiment of the present invention.

FIG. 11 is a cross-sectional view of the embodiment of the present invention, in which a conductive film formed except for the coil pattern portion and the electrode portion is removed.

FIG. 12 is a cross-sectional view in which a ferrite sheet having the same characteristics is joined to a side where a coil and an electrode of the ferrite sheet are provided in one embodiment of the present invention.

[Explanation of symbols]

 1 jig for applying paste 2 ferrite sheet 3, 10 release paper 4 mold 5 coil pattern 6, 6'coil electrode 7 mold 8 sulfur 9 capacitor seat 11, 11 'Capacitor electrodes 12, 13 Conductive adhesive 14 Ferrite sheet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Tomozawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (10)

[Claims] 1. A coil and an electrode are formed on a concave pattern provided on the surface of a ferrite sheet, and another ferrite sheet having magnetic characteristics equivalent to that of the ferrite sheet is attached to the surface of the coil and the electrode. An inductor (L) and a capacitor (C) formed of a dielectric film or sheet having electrodes on both sides, which is joined to the back surface of the ferrite sheet having the coil and the electrode. The electrodes of the inductor (L) and the capacitor (C) are provided on the ferrite sheet having the coil and the electrodes.
A series-combined LC composite device characterized by being coupled with each other. 2. The series-coupling type LC composite element according to claim 1, wherein the ferrite sheet is made of Mn—Zn based ferrite or Ni—Zn based ferrite. 3. The series coupling type LC composite element according to claim 1, wherein the coil is made of Al, Cu, or a noble metal. 4. The series coupling type LC composite element according to claim 1, wherein the electrode on the ferrite sheet side of the capacitor (C) is made of an oxide-based conductor or a noble metal. 5. The series-coupled LC according to claim 1, wherein the capacitor dielectric comprises a thin film of tantalum oxide or nitride, a thin film of barium titanate, or a sintered sheet. Composite element. 6. A surface of unfired ferrite sheet obtained by kneading a ferrite powder and an organic binder on a release paper to a certain thickness, drying the release paper and then peeling the release paper. , The surface of the ferrite sheet is pressed with a die having a convex pattern in the shape of a coil and an electrode formed on the surface, and a concave pattern for the coil and the electrode is formed on the surface, followed by firing, and the back surface of the ferrite sheet After forming one electrode for the capacitor on the capacitor, a dielectric film for the capacitor is formed thereon, and the other electrode is further provided on the surface of the dielectric film, and the recessed pattern-formed ferrite sheet is formed. After forming a metal film to be a coil and an electrode on the surface, the metal film formed other than the concave pattern is removed to form a coil and an electrode, and the ferrite sheet has the same magnetic characteristics on the coil forming side. A method for manufacturing a series-coupling type LC composite element, which comprises bonding another ferrite sheet. 7. The method for manufacturing a serially coupled LC device according to claim 6, wherein a ferrite paste is applied onto the release paper by a doctor blade method. 8. The series according to claim 6, wherein one electrode of the coil and one electrode of the capacitor are joined by a sulfur provided on a ferrite sheet on which the coil and the electrode are formed. Method for manufacturing combined LC element. 9. The method for manufacturing a serially coupled LC device according to claim 6, wherein the dielectric film is formed by any one of a reactive vacuum deposition method, a reactive sputtering method and a plasma-CVD method. 10. A surface of an unsintered ferrite sheet obtained by kneading a ferrite powder and an organic binder on a release paper to a certain thickness, drying the release paper, and peeling the release paper. , A ferrite having a concave pattern formed by pressing with a die having a convex pattern formed in the shape of a coil and an electrode on the surface, forming a concave pattern for the coil and the electrode on the surface, and then firing After forming the metal film to be the coil and electrode on the surface of the sheet, the metal film other than the concave pattern is removed to form the coil and electrode, while the doctor blade method is used to insulate it onto the release paper. Apply a paste made by kneading the body powder and an organic binder, dry it, peel off the release paper, sinter it, and form an electrode film on its front and back surfaces. The back of the ferrite sheet A method for manufacturing a series-coupling type LC composite element, characterized in that it is bonded to the surface with a conductive adhesive and further another ferrite sheet having the same magnetic characteristics is bonded to the coil forming side of the ferrite sheet. .