JP2004006964A - Laminated ceramic chip inductor and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simultaneously achieve impedance increase and conductor resistance decrease in a laminated ceramic chip inductor, and to enhance reliability and reduce cost by laminating layer reduction. <P>SOLUTION: Wound-coil-shaped plated conductors 2, 5 formed by electroforming are respectively transferred onto sheet-formed magnetic layers 1, 6, while the wound-coil-shaped plated conductors 2, 5 are mutually connected via a piercing hole 4 formed on a sheet-formed magnetic layer 3. As a consequence, laminating layer reduction, impedance increase, and conductor resistance decrease are simultaneously achieved. <P>COPYRIGHT: (C)2004,JPO

Description

{Circle over (1)} The present invention relates to a multilayer ceramic chip inductor in which a plurality of sheets each composed of a magnetic or insulating layer and a conductor layer are laminated and fired to form a coiled conductor line, and a method of manufacturing the same.

In recent years, multilayer ceramic chip inductors have been widely used in high-density packaging circuits, such as noise suppression components, as digital devices become smaller and thinner.

Hereinafter, a method for manufacturing a conventional multilayer ceramic chip inductor will be described.

A conductor line (conductor paste) of less than one turn is printed on the magnetic green sheet in advance, and each magnetic green sheet on which the conductive line is printed is laminated and pressed, through a through hole provided in the magnetic green sheet. The conductor lines are electrically connected between the upper and lower layers to form a coil-shaped conductor line, and the laminated magnetic green sheet and coil-shaped conductor line are baked together.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
Japanese Utility Model Publication No. 59-145509

However, in the conventional multilayer ceramic chip inductor, in order to obtain a large impedance (or inductance), it is necessary to increase the number of turns of the coil-shaped conductor line, and accordingly, the number of layers must be increased.

However, when the number of laminations increases in this way, the number of lamination steps increases, and there is a problem that manufacturing costs increase. Furthermore, there has been a problem that the number of places where the conductors are connected between the green sheets increases, and the connection reliability also decreases.

In order to solve these problems, as shown in JP-A-4-93006, a conductor layer of one or more turns is formed on the same plane by a thick film printing technique using a magnetic layer of a magnetic sheet. By laminating them and electrically connecting adjacent upper and lower conductor layers via through holes previously formed in the magnetic layer, a laminate having a relatively large impedance even with a small number of laminates Type ceramic chip inductors have been proposed.

However, even such a proposal has the following two disadvantages.

(1) When manufacturing a small-sized multilayer ceramic chip inductor (for example, an external size of 2.0 mm × 1.25 mm, 1.6 mm × 0.8 mm, etc.) using a thick film conductor printing technique, a fine For printing, the practical range is about 1.5 turns or less in consideration of the production yield and the like. When manufacturing a multilayer ceramic chip inductor having a larger impedance, it is necessary to increase the number of layers.

(2) In order to increase the number of turns in the same plane, it is necessary to reduce the width of the thick-film conductor in the printed thick-film conductor layer. However, if the conductor width is reduced, the conductor resistance increases, so the printed thickness must be increased. There is. However, as the width of the printed conductor is reduced, the conductor thickness must be reduced in order to maintain the printing resolution (for example, when the printed conductor width is 75 μm, the dry thickness is considered to be about 15 μm).

Therefore, the method of simply increasing the number of turns of the thick-film printed conductor as described above is not practical, although the effect of slightly reducing the number of layers is recognized.

Japanese Patent Application Laid-Open No. Hei 3-219605 discloses a method of forming a concave portion in a green sheet and filling the concave portion with a conductive paste to increase the thickness of the thick-film conductor. However, it is difficult to form a complicated concave pattern on a green sheet in terms of mass production method.

Further, as another example, Japanese Patent Application Laid-Open No. Sho 60-176208 discloses that a metal component is punched out of a metal foil as a conductor for coil formation in a laminated component in which a magnetic layer and a conductor of about half turn for coil formation are alternately laminated. It is disclosed that the use of a conductor pattern achieves a reduction in conductor resistance. However, in response to recent miniaturization of components, it is extremely difficult to precisely punch a metal foil so that a conductor can be formed on a minute flat surface. It is impossible to do. Further, it is also difficult to arrange a plurality of stamped metal foils on the sheet-like magnetic layer with high precision at a constant pitch. Further, when metal foils vertically adjacent to each other with the sheet-shaped magnetic layer interposed therebetween are connected at the end of the pattern, poor connection techniques may cause poor connection.

As another approach, a method of manufacturing a multilayer ceramic capacitor by transferring a metal thin film formed on a film to a ceramic green sheet is disclosed in Japanese Patent Publication No. Sho 64-42809 and Japanese Patent Laid-Open Publication No. Hei 4-314876. It has been disclosed.

That is, a desired metal layer was obtained by wet plating on a releasable metal thin film formed by vapor deposition on the film, and an extra metal layer was removed by an etching method as necessary to form a pattern. The material is transferred to a transfer target (ceramic green sheet).

応 用 By applying this transfer technique, it is possible to form a coiled conductor line and transfer it to a magnetic green sheet.

That is, a relatively thin (for example, 10 μm or less) transfer metal thin film formed on a film is etched by a photoresist method to obtain a fine conductor pattern (for example, a conductor width of 40 μm, a line space of 40 μm, etc.), and thereby a large impedance is obtained. It is also possible to obtain a ceramic laminated chip type inductor having the same.

However, it is difficult to obtain a relatively thick (for example, 10 μm or more) transfer metal film with fine pattern accuracy by the above transfer technique.

Because, in the transfer technique using the wet plating as described above, the metal layer once formed on almost the entire surface is removed by an etching method to remove an extra metal layer. It becomes more difficult to form a finer conductor pattern.

Also, since the desired metal pattern remains under the etching resist, it is necessary to remove the etching resist before transferring the metal pattern to the object to be transferred. At the same time, the metal pattern may peel off. This phenomenon is more likely to occur as the thickness of the metal layer increases. This is presumed to be caused by the fact that the thicker the metal layer, the longer the time required for etching and the more the metal thin film layer is attacked by the etchant.

Therefore, even with this technique, the problem of lowering the conductor resistance cannot be sufficiently solved.

In order to solve the above-mentioned problems, a multilayer ceramic chip inductor according to the present invention is configured such that a plurality of magnetic or insulating layers and conductor layers are alternately laminated, and the conductor layers are electrically connected to form a coil-shaped conductor. In the multilayer chip inductor constituting the line, at least one of the conductor layers is a plated conductor layer formed by patterning by an electroforming method.

As described above, according to the multilayer ceramic chip inductor and the method of manufacturing the same of the present invention, since the coil-shaped conductor line is formed using the electroforming (plating) technique, the pattern of several microns or more depends on the resolution of the photoresist. Since the width can be obtained with high precision, a coil-shaped conductor line having a larger number of turns can be obtained in the area of a small chip component than when a conductor is formed by a printing technique.

Therefore, a large impedance value can be obtained even with a small number of layers.

The conductor thickness can be submicron to several tens of microns depending on the thickness of the photoresist and plating conditions, or several millimeters depending on the conditions, so the conductor resistance can be easily controlled. By increasing the film thickness, it is possible to reduce the conductor resistance value while having a fine pattern.

On the other hand, unlike the case where the coil pattern is formed only with the thick film conductor, a relatively dense film is obtained before firing, so that the conductor thickness shrinks relatively little after firing, and the magnetic layer and the conductive layer are not shrunk. There is no occurrence of delamination.

異 な り Furthermore, unlike the case where a coil pattern is formed only with a metal foil that does not shrink at all, cracks are less likely to occur during sintering.

Furthermore, due to the conductor pattern accuracy and the conductor denseness, the reliability of the product characteristics is also increased.

As described above, according to the multilayer ceramic chip inductor and the method of manufacturing the same of the present invention, an excellent effect of simultaneously realizing low lamination, high impedance, and low conductor resistance can be obtained.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view showing the structure of the multilayer ceramic chip inductor according to the first embodiment of the present invention.

In the following drawings, only one piece of the laminated ceramic chip inductor is shown for convenience, but in the actual manufacturing process, a plurality of pieces are formed simultaneously on a plane, and after lamination, they are divided into pieces. .

に お い て In FIG. 1, 1, 3 and 6 are sheet-like magnetic layers. Reference numerals 2 and 5 are wound coil-shaped plated conductors formed by an electroforming method of forming a conductor pattern by plating after forming a resist film having a desired pattern, and transferred to the sheet-shaped magnetic layers 1 and 6, respectively. . Reference numeral 4 denotes a through hole for connecting the wound coil-shaped plated conductors 2 and 5 to each other.

A method of manufacturing the multilayer ceramic chip inductor configured as described above will be described below.

First, a method for producing the coiled plated conductors 2 and 5 for transfer by electroforming will be described with reference to FIG.

(2) As shown in FIG. 2, an Ag release layer 9 having a thickness of 0.1 μm or less is obtained by applying strike Ag plating as a release processing layer having conductivity on the entire surface of the base stainless steel plate 8.

Here, as the strike Ag plating, a very common alkali cyanide Ag plating bath can be used. The composition of the plating bath is illustrated in Table 1 as an example of an alkali cyanide Ag plating bath.

In the case of the Ag plating bath of (Table 1), the Ag release layer 9 of about 0.1 μm can be obtained in about 5 to 20 seconds.

By the way, the Ag release layer 9 has the releasability because the Ag film is strike (high-speed) plated on the base stainless steel plate 8 having poor adhesion to Ag, so that the Ag film has much distortion in the film. This is considered to be due to the fact that the Ag film cannot be firmly adhered to the base stainless steel plate 8.

Also, in order to obtain more optimal releasability between the Ag release layer 9 and the base stainless steel plate 8, the surface of the base stainless steel plate 8 is adjusted to have a surface roughness (Ra) of about 0.05 μm to about 1 μm ( Roughening).

酸 Acid treatment or blast treatment can be used as a method for roughening the surface.

When the surface roughness (Ra) is about 0.05 μm or less, the adhesion between the Ag release layer 9 and the base stainless steel plate 8 becomes insufficient, and the Ag release layer 9 may peel off during the subsequent steps. When the surface roughness (Ra) is about 1 μm or more, the adhesion between the Ag release layer 9 and the base stainless steel plate 8 is too good, and the transfer of the Ag release layer 9 to the magnetic layer can be performed well. Or the resolution of the plating resist pattern 11 may be reduced.

On the other hand, by appropriately roughening the surface of the base stainless steel plate 8, the effect of improving the adhesion of the plating resist pattern 11 formed in the next step or the release of the Ag release layer 9 in the step of removing the plating resist pattern 11 can be achieved. There is also a secondary effect that the mold prevention effect is improved.

The Ag release layer 9 can also be formed by using a silver mirror reaction.

It is also possible to use a material other than stainless steel as the base metal plate and perform release treatment so as to have conductivity. The main usable materials and their release treatment methods are listed in (Table 2).

In addition, it is possible to impart the same effect by giving conductivity to a program board or a pet film or the like in which a copper foil is laminated in addition to the base metal plate, but the metal plate has a higher conductivity. It is efficient without the need to provide.

Especially, stainless steel plates are chemically stable and have a chromium-based oxide film on the surface, so they have good mold release properties and can be used most easily.

After the Ag release layer 9 is thus formed, a dry film resist is laminated on the Ag release layer 9 and, after pre-drying, a 70 μm width of about 2.0 μm in a plane of 2.0 × 1.25 mm ² size. Exposure and development are performed using a photomask for forming a wound coil-shaped plated conductor of .5 turns to form a plating resist pattern 11 having a thickness T = 55 μm.

各種 As the photoresist, various plating resists (liquid, paste, dry film) can be used. With respect to the dry film, the resist thickness is constant, and the thickness of the conductor film can be controlled with relatively high precision.

In the case of a liquid photoresist, it is possible to obtain a conductor pattern accuracy of several microns in width.

(4) In the case of the most common paste-like photoresist, a conductor pattern having a conductor width of about 40 μm and a thickness of about 30 to 40 μm can be obtained.

In this case, for example, 2.0 × 1.25 mm ² size winding conductor pattern of about 5 turns in the plane of the three-turn about the pattern can be easily formed into 1.6 × 0.8 mm ² size in the plane .

According to the characteristics of each resist, the method of coating the resist film can be selected from methods such as printing, spin coating, roll coating, dipping, and laminating.

Exposure is performed with a parallel light UV exposure device, and conditions such as exposure time and light amount may be adjusted to the characteristics of various resists.

現 像 Furthermore, development may be performed using a dedicated developer for various resists.

If necessary, re-exposure to UV light or post-curing can be performed after development to improve the chemical resistance of the resist film.

Next, after the plating resist pattern 11 is formed, it is immersed in an Ag electroplating bath to form a transfer Ag conductor pattern 10 having a required thickness t. In the present embodiment, it was formed so that t = about 50 μm.

The most important thing to note in this step is that a general alkaline Ag plating bath is not used.

(4) The reason for this is that in the case of an alkaline bath, the plating resist pattern 11 formed in the previous step is destroyed because it functions as a stripping solution for the plating resist film.

Therefore, it is necessary to use a weakly alkaline (neutral) or acidic Ag plating bath. As the weak alkaline (neutral) plating bath, those shown in (Table 3) can be used.

The pH is adjusted with ammonia and citric acid. As a result of various experiments, when the pH exceeds 8.5, most of the plating resist is peeled off.

Therefore, it is desirable to set the pH to at least 8.5 or less.

Other acidic plating baths as shown in Table 4 can be used.

メ ッ キ In the Ag plating bath shown in (Table 4), the plating resist was not peeled off because it was acidic. Further, by adding a surfactant (methylimidazole thiol, furfural, funnel oil, etc.), Ag gloss was increased and the surface could be further smoothed.

で は In this example, a weak alkaline (neutral) bath shown in Table 3 was used. The pH was 7.3.

However, the current density in the plating process was about 1 A / dm ² .

This is because, when plating is performed at high speed, if the current density is increased, the Ag conductor pattern 10 is greatly distorted, and the Ag film may be peeled off before transferring the pattern.

In the present embodiment, a plating time of about 260 minutes was required to obtain the Ag conductor pattern 10 having a thickness of about 50 μm.

By the way, the Ag release layer 9 was formed in a strike Ag plating bath (alkaline), but the current density was increased only in the first few minutes in a weak alkaline (neutral) or acidic bath as described above. By increasing the distortion of the Ag film, it is also possible to impart release properties to the Ag film near the interface with the base stainless steel plate 8.

In this case, the configuration is as shown in FIG. 3 and there is no need to provide the Ag release layer 9.

Next, the plating resist pattern 11 is peeled off to obtain a structure as shown in FIG.

(4) The stripping solution for the plating resist pattern 11 may be a solution dedicated to the plating resist film. However, the stripping solution can be usually stripped in about 1 minute by immersing it in a solution of about 5% NaOH (solution temperature: about 40 ° C.).

After the peeling of the plating resist pattern 11 is completed, the Ag release mold 9 having a thickness of about 0.1 μm is soft-etched (the etching time is several seconds) using dilute nitric acid (5%), thereby forming an independent winding as shown in FIG. A coiled Ag conductor pattern 10 is obtained on a base stainless steel plate. The Ag conductor pattern 10 becomes the wound coil-shaped plated conductors 2, 5 of about 2.5 turns shown in FIG.

As the soft etchant of the Ag release layer 9, a sulfuric acid bath of chromic anhydride, a hydrochloric acid bath of ferric chloride, or the like can be used in addition to the dilute nitric acid described above.

(4) With only a few seconds of soft etching, the Ag release layer located under the wound coil-shaped plated conductor pattern is not etched and the wound coil-shaped plated conductor pattern does not peel off.

Next, a method for forming the sheet-like magnetic layers 1, 3, and 6 will be described.

First, a vehicle obtained by dissolving a resin such as butyral, acrylic, or ethyl cellulose in a low-boiling alcohol such as isopropyl alcohol or butanol, or a solvent such as toluene or xylene and a plasticizer such as dibutyl phthalate, and a Ni—Zn—Cu ferrite powder ( A paste (slurry) -like ferrite obtained by kneading an average particle size of 0.5 to 2.0 μm) is formed on a pet film by a doctor blade method, and a state where a little tackiness is left at about 80 to 100 ° C. Dry until dry.

The thickness of each of the sheet-like magnetic layers 1, 3, and 6 is such that the thickness of each of the sheet-like magnetic layers 1 and 6 is about 0.3 to 0.5 mm. After being formed to a thickness of about 20 to 100 μm, a through hole 4 of about 0.15 to 0.3 mm square is made to penetrate by punching or the like.

Next, a transfer step of transferring and laminating the wound coil-shaped plated conductors 2 and 5 and the sheet-shaped magnetic layers 1, 3 and 6 will be described.

{Circle over (1)} First, the wound coil-shaped plated conductor 2 already formed is pressed onto the sheet-shaped magnetic layer 1 formed on the pet film and transferred (may be pressurized and heated as necessary). Alternatively, the sheet-shaped magnetic layer 1 is once released from the pet film, and the coiled plated conductor 2 is wound on the adhesive plasticizer side (the side in contact with the pet film) of the sheet-shaped magnetic layer 1. May be pressed and transferred.

At this time, the wound coil-shaped plated conductor 2 has a good releasability from the base stainless steel plate 8, while it has a good adhesion to the sheet-shaped magnetic layer 1, Since the sheet-shaped magnetic layer 1 is cut off by the compression deformation of the sheet-shaped magnetic layer 1 in the course of the transfer process, the wound coil-shaped plated conductor 2 is easily peeled off by peeling the sheet-shaped magnetic layer 1 from the base stainless steel plate 8. Is transferred to the magnetic layer 1.

At this time, if the sheet strength of the sheet-shaped magnetic layer 1 is insufficient, an adhesive sheet is stuck on the sheet-shaped magnetic layer 1 to compensate for the insufficient strength of the sheet-shaped magnetic layer. You can also.

(4) The wound coil-shaped plated conductor 5 is transferred to the sheet-shaped magnetic layer 6 by the same process.

Further, the sheet-shaped magnetic layer 3 is disposed between the sheet-shaped magnetic layers 1 and 6 to which the two wound coil-plated conductors 2 and 5 thus obtained are transferred. The conductors 2 and 5 are laminated so as to be connected to each other, and the connection between the layers is completed by heating (60 to 120 ° C.) and pressurizing (20 to 500 kg / cm ² ).

However, since electrical connection between the two wound coil-shaped plated conductors 2 and 5 can often be made more ohmic via a thick film conductor, as shown in FIG. It is preferable that the printed thick film conductor 7 is pre-printed and filled in the through hole 4 of the magnetic layer 3, or a bump-shaped plated conductor 7 having substantially the same size as the through hole 4 is transferred.

In the above process, a plurality of conductor patterns are generally formed on one sheet in order to obtain a plurality of multilayer ceramic chip inductors at the same time in order to improve manufacturing efficiency. Therefore, after cutting the sheet into individual pieces, baking is performed at 850 to 950 ° C. for about 1 to 2 hours. Moreover, you may cut after sintering.

Finally, a silver alloy-based lead-out electrode is formed on the opposite outer piece of the cut piece so as to be electrically connected to the inner wound coil-shaped plated conductor, and is fired at about 600 to 850 ° C. By tying, the external electrodes 12 shown in FIG. 6 are formed. If necessary, the external electrodes 12 are plated with Ni, solder, or the like.

積 層 Through such a process, a multilayer ceramic chip inductor having an outer shape of 2.0 × 1.25 mm and a thickness of 0.8 mm was obtained. The internal conductor has a two-layer structure of wound coil-shaped plated conductors 2 and 5 of about 2.5 turns, and has a total of 5 turns of wound coil-plated conductor lines. A value of about 700Ω could be obtained.

The DC resistance value was extremely small, about 0.12Ω, because the Ag conductor thickness was about 50 μm.

In addition, when the multilayer ceramic chip inductor according to the present example was cut and observed, no particular gap was observed at the interface between the Ag conductor and the magnetic layer.

This is because, unlike the case where the wound coil-shaped plated conductor formed by the electroforming method according to the present invention is formed of a thick film conductor having a shrinkage ratio of 40 to 60% by firing, shrinkage by firing is relatively small. (5 to 10%), it is considered that the magnetic material (sintering shrinkage 5 to 20%) was densely sintered around the Ag conductor.

Further, when the wound coil-shaped plated conductor is a metal foil, the metal foil is denser than the plating film, so that it expands thermally and hardly shrinks. Although cracks may occur due to the difference, in the case of a wound coil-shaped plated conductor formed by the electroforming method according to the present embodiment, cracks rarely occur.

(Embodiment 2)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 7 is an exploded perspective view showing the structure of the multilayer ceramic chip inductor according to the second embodiment of the present invention.

In FIG. 7, 13 and 18 are sheet-like magnetic layers, and 15 is a sheet-like magnetic layer in which a through hole 16 is formed. Reference numeral 14 denotes a wound coil-shaped plated conductor for transfer formed by electroforming, and reference numeral 17 denotes a thick-film conductor printed on a sheet-like magnetic layer in which a through hole 16 is formed. The coiled plated conductor for transfer 14 formed by electroforming and the thick film conductor 17 printed are connected to each other through a through hole 16.

A method of manufacturing the multilayer ceramic chip inductor configured as described above will be described below.

First, the production of the wound coil-shaped plated conductor 14 for transfer can be performed by the same electroforming method as in the first embodiment.

In this embodiment, a pattern of about 3.5 turns was obtained in a 1.6 × 0.8 mm ² size plane with a pattern rule of about 40 μm width and 35 μm thickness.

レ ジ ス ト The used resist is a printable high-sensitivity paste-like resist.

Next, a method of forming the sheet-like magnetic layers 13, 15, 18 will be described.

Vehicle in which resin such as butyral, acryl, ethylcellulose and the like is dissolved in a high boiling point solvent such as terpineol and a plasticizer such as dibutyl phthalate, and Ni / Zn / Cu ferrite powder (average particle size 0.5 to 2.0 m) Is formed on a pet film by printing using a metal mask. Thereafter, drying is performed at about 80 to 100 ° C. (printing and drying are repeated several times as necessary) to obtain sheet-like magnetic layers 13 and 18 formed to have a thickness of about 0.3 to 0.5 mm.

Alternatively, in addition to the above method, the sheet-like magnetic layers 13 and 18 can be obtained by laminating several sheet-like magnetic layers printed and dried to about 50 to 100 μm.

The sheet-like magnetic layer 15 is formed by forming a pattern having through holes 16 on a pet film by screen printing, and adjusting the thickness to about 40 to 100 μm.

First, the wound coil-shaped plated conductor 14 already formed is pressed and transferred onto the sheet-shaped magnetic layer 13 formed on the pet film. The pressing conditions are preferably selected from the range of 20 to 100 kg / cm ² , and the heating conditions are preferably selected from the range of 60 to 120 ° C.

と き At this time, the wound coil-shaped plated conductor 14 has a good releasability from the base stainless steel plate, and also has a good adhesiveness to the sheet-like magnetic layer 13. Further, since the wound coil-shaped plated conductor 14 has a relatively small pattern width of 40 μm, it also has an effect of slightly penetrating the sheet-shaped magnetic layer 13. Is transferred to

Note that, similarly to the first embodiment, the transfer can be performed by pressing the wound coil-shaped plated conductor 14 against the plasticizer surface side of the sheet-shaped magnetic layer 13.

Next, the thick film conductor 17 is printed on the sheet-like magnetic layer 15 having the through holes 16.

Further, the sheet-shaped magnetic layer 13 on which the wound coil-shaped plated conductor 14 obtained as described above is transferred and the sheet-shaped magnetic layer 15 on which the thick film conductor 17 is printed are overlapped. The plated conductor 14 and the thick-film conductor 17 are laminated so as to be connected to each other, and a sheet-shaped magnetic layer 18 is further laminated thereon, and heated and pressed to form an integrated laminate.

In the above process, a plurality of conductor patterns are formed on one sheet in order to obtain a plurality of laminated ceramic chip inductors at the same time to improve manufacturing efficiency. Therefore, after cutting the sheet into individual pieces, baking is performed at 850 to 950 ° C. for about 1 to 2 hours.

An extraction electrode is formed on each of the opposite ends of the cut piece so as to be connected to the internally wound coil-shaped plated conductor, and is sintered at about 600 to 850 ° C. to obtain an external electrode shown in FIG. An electrode 12 is formed. If necessary, the external electrodes 12 are plated with Ni, solder, or the like.

By such a process, a laminated ceramic chip inductor having an outer shape of 1.6 × 0.8 mm ² and a thickness of 0.8 mm was obtained. The internal conductor has a two-layer structure of a wound coil-shaped plated conductor 14 of about 3.5 turns and a linear thick film conductor 17 connected through a through hole, for a total of 3.5 turns. Because of having the coil-shaped plated conductor line, the impedance at 100 MHz could be obtained as about 300Ω.

The DC resistance value could be set to about 0.19Ω because the Ag conductor thickness was about 35 μm.

In the present embodiment, the transfer coil-shaped plated conductor 14 for transfer and the thick film conductor 17 are only used. The thick film conductors 17 may be connected alternately.

As described in the present embodiment, by combining the thick film conductor and the wound coil-shaped plated conductor, the connection reliability is further increased as compared with the case where the wound coil-shaped plated conductors are connected to each other.

This is presumed to be because the thick film conductor is easily deformed during lamination, and is sintered in a state where the adhesion to the wound coil-shaped plated conductor is enhanced.

(Embodiment 3)
Hereinafter, Embodiment 3 of the present invention will be described with reference to the drawings.

FIG. 8 is an exploded perspective view showing a multilayer ceramic chip inductor structure according to Embodiment 3 of the present invention.

に お い て In FIG. 8, 19 and 24 are sheet-like magnetic layers, and 21 is a sheet-like magnetic layer having a through hole 22. Reference numerals 20 and 23 are wound coil-shaped plated conductors for transfer formed by electroforming. Reference numeral 25 denotes a thick film conductor printed so as to fill the through holes 22 formed in the sheet-like magnetic layer 21. The coiled plated conductors 20 and 23 for transfer formed by electroforming and the printed thick film conductor 25 are connected to each other through the through hole 22.

A method of manufacturing the multilayer ceramic chip inductor configured as described above will be described below.

First, the method of producing the coiled plated conductors 20 and 23 for transfer by the electroforming method can be performed by the same electroforming method as in the first embodiment.

In the present embodiment, the winding coil-shaped plated conductor 20 for transfer is about 3.5 turns, and the pattern rule is about 40 μm wide and 35 μm thick in a 1.6 × 0.8 mm ² size plane. And a pattern of about 2.5 turns was obtained as the wound coil-shaped plated conductor 23.

レ ジ ス ト The used resist is a printable high-sensitivity paste-like resist.

Next, a method of forming the sheet-like magnetic layers 19, 21 and 24 will be described.

Vehicle in which resin such as butyral, acryl, ethylcellulose and the like is dissolved in a high boiling point solvent such as terpineol and a plasticizer such as dibutyl phthalate, and Ni / Zn / Cu ferrite powder (average particle size 0.5 to 2.0 m) Is formed on a pet film by printing using a metal mask on a pet film, and dried at about 80 to 100 ° C. until a little tackiness is left. The sheet-like magnetic layers 19 and 24 formed to have a thickness of about 5 mm are obtained. The sheet-like magnetic layer 21 is formed by forming a pattern having through holes 22 on a pet film by screen printing, and adjusting the thickness to be about 40 to 100 μm.

(4) The thick film conductor 25 is printed so that the through-hole 22 is filled with the thick film conductor.

(4) Next, the wound coil-shaped plated conductor 20 for transfer that has already been formed is pressed against the sheet-shaped magnetic layer 19 formed on the pet film and transferred (pressing and heating as necessary).

Similarly, the coiled plated conductor 23 for transfer is also transferred to the sheet-like magnetic layer 24.

At this time, the transfer may be made to the sheet-like magnetic layer 21 instead of the sheet-like magnetic layer 24.

Further, a sheet-like magnetic material having a through hole 22 between the sheet-like magnetic material layer 19 to which the wound coil-shaped plated conductor 20 is transferred and the sheet-shaped magnetic material layer 24 to which the wound coil-shaped plated conductor 23 is transferred is provided. The body layer 21 is arranged, the wound coil-shaped plated conductors 20 and 23 for transfer are laminated so as to be connected to each other via the thick-film conductor 25 filled in the through-hole 22, and heated and pressed to be integrally laminated. Body.

In the above process, a plurality of conductor patterns are generally formed on one sheet in order to obtain a plurality of multilayer ceramic chip inductors at the same time in order to improve manufacturing efficiency. Therefore, the sheet is cut into individual pieces, and then fired at 850 to 1000 ° C. for about 1 to 2 hours.

Finally, an extraction electrode is formed on each of the opposite ends of the cut piece so as to be connected to the internally wound coil-shaped plated conductor, and is sintered at about 600 to 850 ° C. so that the external electrode shown in FIG. An electrode 12 is formed. Further, if necessary, the external electrodes 12 are plated with Ni, solder, or the like.

By such a process, a laminated ceramic chip inductor having an outer shape of 1.6 × 0.8 mm ² and a thickness of 0.8 mm was obtained. The inner conductor has a two-layer structure of a wound coil-shaped plated conductor 20 having a conductor width of about 40 μm and about 3.5 turns, and a wound coil-shaped plated conductor 23 of about 2.5 turns connected through a through hole. Since it has a total of 6 turns of the coiled plated conductor line, an impedance of about 1000Ω can be obtained at 100 MHz.

The DC resistance value could be set to about 0.32Ω because the thickness of the wound coil-shaped plated conductor was about 35 μm.

(Embodiment 4)
Hereinafter, Embodiment 4 of the present invention will be described with reference to the drawings.

FIG. 9 is an exploded perspective view showing the structure of the multilayer ceramic chip inductor according to the fourth embodiment of the present invention.

In FIG. 9, 26 and 31 are sheet-like magnetic layers, 28 is a sheet-like magnetic layer having through holes 29, and 27 and 30 are wound coil-shaped plated conductors for transfer formed by electroforming.

The wound coil-shaped plated conductors 27 and 30 for transfer formed by the electroforming method are connected to each other through the through-hole 29.

The manufacturing method of the multilayer ceramic chip inductor configured as described above is the same as that of the first embodiment, and a description thereof will be omitted.

According to this example, a multilayer ceramic chip inductor having an outer shape of 2.0 × 1.25 mm ² and a thickness of 0.8 mm was obtained. The inner conductor has a two-layer structure of a wound coil-shaped plated conductor 27 having a conductor width of about 40 μm and a length of about 5.5 turns and a wound coil-shaped plated conductor 30 of about 2.5 turns connected through a through hole 29. Since it has a total of 8 turns of the coiled plated conductor line, an impedance of about 1400Ω was obtained at 100 MHz.

The DC resistance value could be set to about 0.47Ω because the thickness of the wound coil-shaped plated conductor was about 35 μm.

(Embodiment 5)
Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings.

積 層 Since the multilayer ceramic chip inductor in this example has the same structure as in the second embodiment, it will be described with reference to FIG.

7, reference numerals 13 and 18 denote sheet-shaped magnetic layers, 15 denotes a sheet-shaped magnetic layer having a through-hole 16, 14 denotes a coiled plated conductor for transfer formed by electroforming, and 17 denotes a through-hole 16 A thick-film conductor printed on a sheet-like magnetic material layer having the above-mentioned structure, and the wound coil-shaped plated conductor for transfer 14 formed by electroforming and the printed thick-film conductor 17 are formed through the through-hole 16. Connect to each other.

A method of manufacturing the multilayer ceramic chip inductor configured as described above will be described below.

First, in the same manner as in the second embodiment, a wound coil-shaped plating for transferring a pattern of about 3.5 turns with a pattern rule of about 40 μm width and 35 μm thickness in a plane of 1.6 × 0.8 mm ² size. The conductor 14 was obtained.

Next, a method for forming the sheet-shaped magnetic layer 13 will be described with reference to FIG.

Vehicle in which resin such as butyral, acryl, ethylcellulose and the like is dissolved in a high boiling point solvent such as terpineol and a plasticizer such as dibutyl phthalate, and Ni / Zn / Cu ferrite powder (average particle size 0.5 to 2.0 m) Is printed on the base stainless plate 32 on which the Ag conductor pattern 34 is formed using a metal mask and dried at about 80 to 100 ° C. (repeat printing and drying as necessary). ), The sheet-like magnetic layer 33 is formed to have a thickness of about 0.3 to 0.5 mm.

Next, a heat-releasable sheet 35 is adhered from the upper layer of the sheet-like magnetic layer 33 (heating and pressing may be performed if necessary). The body layer 33 is simultaneously released from the base stainless steel plate 32.

グ リ ー ン In this way, a green sheet in which the wound coil-shaped plated conductor 14 is formed on the sheet-shaped magnetic layer 13 can be obtained.

If necessary, before the sheet-shaped magnetic layer 33 is formed by printing, the Ag release layer 9 as shown in FIG. 2 in the first embodiment is provided on the base stainless steel plate 32 on which the Ag conductor pattern 34 is formed. You can also.

に よ り With such an Ag release layer, the releasability between the sheet-like magnetic layer 33 and the base stainless steel plate 32 can be further improved. The Ag release layer can be formed by dip-coating a liquid fluorine-based coupling agent (such as perfluorodecyltriethoxysilane) and drying at about 200 ° C. The thickness of the release layer is preferably about 0.1 μm.

On the other hand, the sheet-like magnetic layer 15 is formed in a pattern having the through-holes 16 on the pet film by screen printing. The thickness is adjusted to be about 40 to 100 μm, and this sheet is laminated on the wound coil-shaped plated conductor 14.

It is preferable that the pressing conditions during the lamination be selected from the range of 20 to 500 kg / cm ² and the heating conditions be selected from the range of 80 to 120 ° C.

In the present embodiment, the wound coil-shaped plated conductor 14 cuts into the sheet-shaped magnetic layer 13 and has little unevenness, so that the sheet-shaped magnetic layer 15 is easily transferred onto the sheet-shaped magnetic layer 13. You.

Next, a thick film conductor 17 is printed on the sheet-like magnetic layer 15 via the through-hole 16 so as to be connected to the wound coil-plated conductor layer 14.

Furthermore, the sheet-shaped magnetic layer 18 is laminated thereon, and heated and pressed to form an integrated laminate. In this case, the sheet-shaped magnetic layer 18 may be directly printed and laminated.

The remaining steps (cutting of green sheet, firing, formation of end face electrodes, etc.) are exactly the same as in the second embodiment.

The electrical characteristics of the multilayer ceramic chip inductor in this embodiment are also equivalent to those in the second embodiment.

(Embodiment 6)
Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings.

This example has the same structure as the second and fifth embodiments, and will be described with reference to FIGS.

In FIG. 7, 13 and 18 are sheet-like magnetic layers, and 15 is a sheet-like magnetic layer having a through hole 16. Reference numeral 14 denotes a wound coil-shaped plated conductor for transfer formed by electroforming, and reference numeral 17 denotes a thick-film conductor printed on a sheet-shaped magnetic layer having a through hole 16. The coiled plated conductor for transfer 14 formed by electroforming and the printed thick film conductor 17 are connected to each other through a through hole 16.

In the method of manufacturing the multilayer ceramic chip inductor configured as described above, a step of transferring the wound coil-shaped plated conductor 14 for transfer to the sheet-shaped magnetic layer 13 will be described below with reference to FIG.

As in the second embodiment, an Ag conductor pattern 38 of about 3.5 turns in a 1.6 × 0.8 mm ² size plane with a pattern rule of about 40 μm in width and 35 μm in thickness (winding coil for transfer) (Corresponding to the plated conductor 14) was obtained on the base stainless steel plate 36. A conductive Ag release layer (strike Ag plating layer) 37 is formed between the Ag conductor pattern 38 and the base stainless steel plate 36 (FIG. 11A).

Next, by foaming under heat from the upper part of the Ag conductor pattern 38, a foam sheet 39 having a heat releasing property from the base stainless steel plate 36 is attached (if necessary, heating and pressing may be performed) (FIG. 11B )).

(4) Since the foam sheet 39 has a strong adhesive force, when the foam sheet 39 is peeled off from the base stainless steel plate 36, the Ag conductor pattern 38 and the Ag release layer 37 are transferred to the foam sheet 39 (FIG. 11C).

The sheet-shaped magnetic layer 40 (thickness: 50 μm to 500 μm) formed in advance on a pet film or the like by a technique such as printing is applied to the Ag release layer 37 on the Ag conductor pattern 38 transferred onto the foam sheet 39. To be laminated. In this case, the sheet-like magnetic material layer 40 is laminated so that the plasticizer surface side is in contact with the Ag release layer 37, and the lamination is performed until the total thickness of the sheet-like magnetic material layer 40 becomes about 0.3 to 0.5 mm. Repeat (FIG. 11D).

Of course, if necessary, pressure and heat may be applied under appropriate conditions during lamination.

Next, the integrated body including the sheet-shaped magnetic layer 40, the Ag conductor pattern 38, the Ag release layer 37, and the foam sheet 39 is heated at about 120 ° C. for 10 minutes to foam and release the foam sheet 39. A sheet-like magnetic layer 40 (corresponding to the sheet-like magnetic layer 13 in FIG. 7) integrated with the Ag conductor pattern 38 (corresponding to the coiled plated conductor 14 in FIG. 7) can be obtained (FIG. 11 ( e)).

Next, as shown in FIG. 7, a sheet-like magnetic layer 15 having a through-hole 16 is formed on the wound coil-shaped plated conductor 14 by lamination or printing technique, and a through-hole is further formed on the sheet-like magnetic layer 15. A thick film conductor 17 is laminated or printed so as to be connected to the wound coil-shaped plated conductor layer 14 via the conductor 16.

Furthermore, the sheet-shaped magnetic layer 18 is laminated thereon, and heated and pressed to form an integrated laminate. In this case, the sheet-shaped magnetic layer 18 may be directly printed and laminated.

The remaining steps (cutting of green sheet, firing, formation of end face electrodes, etc.) are exactly the same as those in Example 2.

The electrical characteristics of the multilayer ceramic chip inductor in this example were also equivalent to those in the second embodiment.

In this embodiment, the meandering coil-shaped plated conductor is used, but the coil may be formed by combining linear conductor patterns.

(Embodiment 7)
Hereinafter, Embodiment 7 will be described with reference to the drawings as an application example of the present invention.

FIG. 12 is an exploded perspective view showing the structure of the multilayer ceramic chip inductor according to the seventh embodiment of the present invention.

In FIG. 12, reference numerals 41 and 43 denote sheet-like magnetic layers, and reference numeral 42 denotes a meandering coil-shaped plated conductor for transfer formed by electroforming.

The meandering coil-shaped plated conductor for transfer 42 formed by the electroforming method is arranged so as to be drawn out to both ends of the chip of the multilayer ceramic chip inductor.

The manufacturing method of the multilayer ceramic chip inductor configured as described above is the same as that of the first embodiment, and therefore will not be described.

According to this example, a multilayer ceramic chip inductor having an outer shape of 2.0 × 1.25 mm ² and a thickness of 0.8 mm was obtained. The inner conductor had a conductor width of about 50 μm, and a meandering coil-shaped plated conductor penetrated in the longitudinal direction of the magnetic layer. The impedance at 100 MHz was about 120Ω.

The DC resistance value could be set to about 0.08Ω when the thickness of the meandering coil-shaped plated conductor 42 was about 35 μm.

で は In this embodiment, a meandering coil-shaped plated conductor is used, but a linear plated conductor pattern may be used.

In the above seven embodiments, Ag was used as each of the wound or meandering coil-shaped plated conductors for transfer. However, if cost, specific resistance and oxidation resistance were not considered, Au, Pt , Pd, Cu, Ni, etc., and alloys thereof can also be used as appropriate.

In addition, although all the laminated bodies are listed only as examples of Ni-Zn-Cu-based magnetic materials, other Ni-Zn-based, Mn-Zn-based magnetic materials and various low dielectric constant insulating materials are used. Needless to say, it is also possible to form a multilayer ceramic chip inductor having air-core coil characteristics.

(Comparative example)
Next, comparative examples for each of the above embodiments will be described with reference to the drawings.

FIG. 14 is a perspective view showing a method of manufacturing the multilayer ceramic chip inductor in the comparative example.

In FIG. 14, 101 and 111 are sheet-like magnetic layers, and 102, 104, 106, 108 and 110 are thick film conductor layers for forming a coiled plated conductor of about half turn.

Reference numerals 103, 105, 107, and 109 denote sheet-like magnetic layers serving as insulating layers for laminating the thick-film conductors of about half a turn, and the conductors are exposed only at the edges of the conductive layers of about half-turns. Are arranged and laminated so that

A method of manufacturing the multilayer ceramic chip inductor configured as described above will be described below.

First, as shown in FIG. 14A, a ferrite paste is printed in a rectangular shape to obtain a sheet 101. Next, the conductive paste is printed on the sheet 101 by about タ ー ン turn to form the conductive line 102 (FIG. 14B).

(4) Further, a sheet 103 is formed by printing a ferrite paste so as to cover a part of the conductor line 102 (FIG. 14C).

{Circle around (2)} Then, a thick conductive layer 104 of about 1/2 turn is formed by printing an Ag conductive paste so as to be connected to the end of the conductive line 102 (FIG. 14D).

(4) Similarly, as shown in FIGS. 14 (e) to 14 (k), they are printed and laminated, and sintered at a high temperature to obtain a ceramic laminated body having a total of 2.5 turns of a coiled plated conductor line.

In this comparative example, a conductor pattern was obtained in a 1.6 × 0.8 mm plane with a pattern rule of about 150 μm in width and 12 μm in printed dry thickness.

Since the inner conductor has a 2.5-turn wound coil-shaped plated conductor, an impedance of about 150Ω could be obtained at 100 MHz.

The DC resistance was about 0.16Ω, with the thickness of the wound coil-shaped plated conductor after sintering being about 8 μm.

In this comparative example, although the laminated structure has a total of 11 layers, the wound coil-shaped plated conductor can obtain only 2.5 turns, and therefore, the impedance is small and the conductor resistance value is the impedance value in proportion to the number of layers. Great against.

The process is complicated, and the connection reliability between the conductor layers is poor.

By the way, in the present comparative example, each thick film conductor layer can be formed by transferring the plated conductor pattern by the electroforming method in the present embodiment, and the conductor resistance can be reduced. Effects such as an increase in the impedance value cannot be expected.

(Embodiment 8)
Hereinafter, an eighth embodiment of the present invention will be described with reference to the drawings.

FIG. 15 is an exploded perspective view showing the structure of the multilayer ceramic chip inductor according to the eighth embodiment of the present invention.

In FIG. 15, reference numerals 201 and 206 denote sheet-like magnetic layers, reference numeral 203 denotes a sheet-like magnetic layer having a through hole 207 formed in a substantially central portion, and reference numerals 202 and 205 denote windings for transfer formed in a meandering shape by electroforming. The coil-shaped plated conductor 204 is a bump-shaped plated conductor formed in the through hole 207 of the sheet-shaped magnetic layer 203 by electroforming, and is a coiled plated coil conductor 202 for transfer formed by electroforming. 205 is electrically connected through the bump-shaped plated conductor 204 transferred to the through hole 207.

The manufacturing method of the multilayer ceramic chip inductor configured as described above will be described below. First, a method for producing the coiled plated conductors 202 and 205 for transfer by electroforming and the bump-shaped plated conductor 204 for connecting the coiled plated conductors 202 and 205 will be described with reference to FIG. As shown in FIG. 16A, a liquid resist is screen-printed on the base stainless plate 210 and dried at about 100 ° C. to obtain a resist film 211 of about 25 μm. Next, the resist film 211 is exposed to parallel light under predetermined conditions, and is immediately developed using an aqueous solution of sodium carbonate. Next, after development, the plate is washed sufficiently with water, further immersed in 0.5% to 1 mm of a 5% H ₂ SO ₄ solution, subjected to an acid activation treatment, and subjected to a neutral strike-free silver plating not containing cyanide manufactured by Daiwa Kasei Co., Ltd. A release layer 212 is obtained. The strike silver plating time is about 1 minute (current density 0.3 A / dm ² ) and the plating film thickness is about 0.1 μm.

Next, a commercially available Ag-free plating solution containing no cyanide (Daiwa Kasei Co., Ltd.) is used, the pH is about 1.0, an acid bath is used, the current density is 1 A / dm ² , and the plating conditions are about 20 minutes. The Ag plating film 213 of FIG.

The silver plating solution containing no cyan used in the present embodiment has no toxicity, can achieve work safety, simplify the treatment of drainage, and can improve work efficiency and reduce manufacturing cost. is there.

Next, as shown in FIG. 16B, the resist film 211 was peeled off by dipping in a 5% NaOH solution. With the above method, the diameter of the through-hole 207 of the coiled plated conductors 202 and 205 of 1608 size, 35 μm in width, 25 μm in space, 20 μm in thickness, about 2.5 turns, and the sheet-like magnetic layer 203 is 0.1. Is provided with a bump-shaped Ag plating pattern 204 for filling through holes.

Next, a method for forming the sheet-like magnetic layers 201, 203, and 206 will be described.

First, a high-temperature calcined powder (800 to 1100 ° C.) of a Ni—Zn—Cu ferrite, a resin such as butyral, acryl, and ethyl cellulose, a low-boiling solvent such as toluene and xylene, a plasticizer such as dibutyl phthalate, and a small amount of additives Is mixed with a pot to form a film with a doctor blade device to obtain green sheets of about 100 μm and 40 μm.

Further, four green sheets of about 100 μm are laminated to obtain green sheets 201 and 206 of about 400 μm. On the other hand, a green sheet 203 in which a through hole having a diameter of 0.1 is formed on a 40 μm green sheet using a puncher (a device for mechanically forming a hole using a mold pin).

The green sheets 201 and 206 thus obtained are hot-pressed on the wound coil-shaped plated conductors 202 and 205, respectively, and the green sheets 201 and 206 are released from the base stainless steel plate to thereby form a wound coil-shaped plated conductor. Are transferred to obtain sheet-like magnetic layers 201 and 206. Similarly, the sheet-shaped magnetic layer 203 to which the bump-shaped Ag plating pattern has been transferred is obtained by transferring the bump-shaped Ag plating pattern 204 after positioning the green sheet 203 having a through hole having a diameter of 0.1. .

At this time, the thermal transfer conditions are 100 ° C., 70 kg / cm ² , and 5 seconds. As shown in FIG. 17A, the transfer is performed so that the plated conductors bite into each green sheet.

The sheet-like magnetic layers 201, 203, and 206 obtained in this manner are sequentially stacked so that they are electrically connected to each other and aligned so as to form one coil. It is fired at 〜920 ° C. to obtain a laminate having an outer size of 1.6 × 0.8 and a thickness of about 0.8.

In general, ferrite powder uses ferrite fine powder (0.2 to 1.0 μm) calcined at 700 to 800 ° C. in order to increase sintering density, and shrinks by about 15 to 20% in the sintering process. Although it is usual to perform sintering, in this example, sintering shrinkage was suppressed to about 2 to 10% by using a high-temperature calcined powder (1 to 3 μm) at 800 to 1100 ° C. This is because the Ag-plated conductor shrinks only slightly during the sintering process, so that the shrinkage is matched as much as possible to reduce the internal strain after sintering.

However, generally, when the calcining temperature of the powder is increased, the shrinkage ratio is reduced, but the magnetic properties are degraded. Therefore, it is important to add an additive that minimizes the deterioration of magnetic properties.

Research shows that it is effective to add a small amount of organic lead compounds such as lead octylate (0.1-1.0% of ferrite) as an additive to suppress magnetic property degradation while maintaining shrinkage. I found it.

This is because the organic lead compound disperses very well in the ferrite slurry, so that atomic atomic metal Pb or atomic PbO thermally decomposed during the sintering process at the grain boundaries of the ferrite powder efficiently and effectively dissolves and the sinterability is improved. It is thought to improve.

On the other hand, powder such as PbO has a high specific gravity, so that it is easily separated from ferrite in a slurry and has poor dispersibility. Further, the reactivity of the ferrite powder is also inferior to that of a substance (atomic metal lead or atomic PbO) generated by thermal decomposition of an organic lead compound. Therefore, the addition of an oxide powder such as PbO has little effect.

It is also effective to introduce non-shrink ferrite instead of high temperature fuel.

This advance to prepare a powder which is previously reduced by calcining a portion Fe ₂ O ₃ as the Fe ₂ O ₃ of Ni · Zn · Cu ferrite, separately metals Fe powder and unreacted NiO, ZnO, and CuO In addition, in the sintering process, the sintering shrinkage is eliminated by adjusting the ratio of the metal Fe powder oxidized and expanded by Fe ₂ O ₃ and the so-called general sintering shrinkage ratio. Specific examples are described in (Table 5).

チ ッ プ As shown in (Table 5), it is easy to produce chip beads using low-shrinkage ferrite powder or non-shrinkage ferrite powder.

Furthermore, chip deburring, external electrode formation and external electrode plating (Ni, solder) are performed as a final step to complete the chip beads. The electrical characteristics are slightly different depending on the material used, and are shown in (Table 6). Note that the sintering temperature is 910 ° C., and the data when kept for 1 hour is shown.

INDUSTRIAL APPLICABILITY The multilayer ceramic chip inductor and the method of manufacturing the same according to the present invention can obtain a large impedance value even with a small number of layers, and can also be used for high-density mounting circuits and the like accompanying digital devices such as noise suppression components that are smaller and thinner. Applicable.

FIG. 2 is an exploded perspective view showing the structure of the multilayer ceramic chip inductor according to the first embodiment of the present invention. Explanatory drawing showing the manufacturing process of the multilayer ceramic chip inductor in the first embodiment. Explanatory drawing which shows the manufacturing process of the laminated ceramic chip inductor in the same Example. Explanatory drawing which shows the manufacturing process of the laminated ceramic chip inductor in the same Example. Explanatory drawing which shows the manufacturing process of the laminated ceramic chip inductor in the same Example. External appearance perspective view of the multilayer ceramic chip inductor in each of the embodiments. Exploded perspective view showing the structure of the multilayer ceramic chip inductor in the second, fifth and sixth embodiments. Exploded perspective view showing the structure of the multilayer ceramic chip inductor according to the third embodiment. Exploded perspective view showing the structure of the multilayer ceramic chip inductor according to the fourth embodiment. Explanatory drawing showing the manufacturing process of the multilayer ceramic chip inductor in the fifth embodiment. Explanatory drawing showing the manufacturing process of the multilayer ceramic chip inductor according to the sixth embodiment. Exploded perspective view showing the structure of the multilayer ceramic chip inductor according to the seventh embodiment. Partial perspective view showing another example of the structure of the multilayer ceramic chip inductor according to the first embodiment of the present invention. Explanatory drawing which shows the manufacturing process of the multilayer ceramic chip inductor as a comparative example with respect to each Example. Exploded perspective view showing the structure of the multilayer ceramic inductor in the eighth embodiment. Diagram explaining the same process Diagram explaining the same process

Explanation of reference numerals

1,3,6,13,15,18,19,21,24,26,28,31,33,40,41,43 Magnetic sheet layer 2,5,14,20,23,27,30 Coiled plated conductor 4,16 Through hole 8,32,36 Base stainless steel plate 9,37 Ag release layer 10,34,38 Ag conductor pattern 11 Plating resist pattern 12 External electrode 17,25 Thick film conductor 39 Foam sheet 42 Meandering coiled plated conductor

Claims (30)

At least one pair of insulating layers, and at least one conductor pattern constituting a coiled conductor line sandwiched between the at least one pair of insulating layers, the at least one conductor pattern is directly formed on the insulating layer by electroforming. The formed multilayer ceramic chip inductor. 2. The multilayer ceramic chip inductor according to claim 1, wherein at least one conductor pattern is formed directly on the insulating layer by transfer. 3. The multilayer ceramic chip inductor according to claim 1, wherein there is no gap at an interface between at least one conductor pattern and the insulating layer. The multilayer ceramic chip inductor according to claim 1, further comprising a plurality of conductor patterns, wherein at least two of the conductor patterns are electrically connected by a thick-film conductor formed by printing. 4. The multilayer ceramic chip inductor according to claim 1, wherein at least one electroformed conductor pattern has a meandering shape. The multilayer ceramic chip inductor according to any one of claims 1 to 3, wherein at least one electroformed conductor pattern is linear. 4. The multilayer ceramic chip inductor according to claim 1, wherein at least one pair of insulating layers is made of a magnetic material. The multilayer ceramic chip inductor according to any one of claims 1 to 3, wherein the insulating layer is made of a powder having no shrinkage or low shrinkage during the sintering process. The multilayer ceramic chip inductor according to any one of claims 1 to 3, wherein the pair of insulating layers and the conductor pattern are integrally sintered. A step of forming a conductor pattern on a base plate having conductivity by electroforming, a step of directly transferring the electroformed conductor pattern to a first insulating layer, and a step of forming the first insulating layer having the electroformed conductor pattern. Forming a second insulating layer on a surface of the multilayer ceramic chip inductor. A step of forming a plurality of first insulating layers to which the electroformed conductor patterns are transferred; and a step of laminating the plurality of first insulating layers while electrically connecting the plurality of electroformed conductor patterns to each other. Item 11. The method for manufacturing a multilayer ceramic chip inductor according to Item 10. The method of manufacturing a multilayer ceramic chip inductor according to claim 11, further comprising a step of sandwiching a third insulating layer having a through hole between the plurality of first insulating layers. The method for manufacturing a multilayer ceramic chip inductor according to claim 11, further comprising a step of sandwiching a third insulating layer having a through hole filled with a printed thick film conductor between the plurality of first insulating layers. The transferring step includes: forming a first insulating layer on a surface of the conductive base plate having the electroformed conductor pattern; bonding a thermal release sheet onto the first insulating layer; The multilayer ceramic chip according to claim 10, further comprising: a step of peeling off the first insulating layer and the thermal release sheet having the same from the conductive base plate; and a step of peeling off the thermal release sheet by heating. Manufacturing method of inductor. The transferring step is a step of bonding a foam sheet having a heat releasing property on a surface of the conductive base plate having the electroformed conductor pattern, and the step of bonding the heat releasing foam sheet and the electroformed conductor pattern to the conductive sheet. Peeling off from the base plate, forming the first insulating layer on the surface of the heat releasing foam sheet having the electroformed conductor pattern, and peeling the heat releasing foam sheet by heating The method for manufacturing a multilayer ceramic chip inductor according to claim 10, comprising: The step of forming the electroformed conductor pattern includes a step of covering the conductive base plate with a photoresist film so as to expose the conductive base plate in a desired pattern, and a step of forming a conductive layer on the conductive base plate so as to cover the photoresist film. 11. The method for manufacturing a multilayer ceramic chip inductor according to claim 10, comprising a step of forming a conductive film. The method for manufacturing a multilayer ceramic chip inductor according to claim 10, wherein the conductive base plate is a metal plate that has been subjected to a release treatment so as to have conductivity. The method for manufacturing a multilayer ceramic chip inductor according to claim 10, wherein the conductive base plate is a stainless steel plate. The method of manufacturing a multilayer ceramic chip inductor according to claim 10, wherein the electroformed conductor pattern is formed by an Ag plating bath having a pH of 8.5 or less. The method for manufacturing a multilayer ceramic chip inductor according to claim 10, wherein the surface roughness (Ra) of the conductive base plate is 0.05 to 1 m. The method for manufacturing a multilayer ceramic chip inductor according to claim 12, wherein the first, second, and third insulating layers are made of a magnetic material. 13. The method for manufacturing a multilayer ceramic chip inductor according to claim 12, wherein at least one of the second and third insulating layers is made of a low dielectric constant material. The method for manufacturing a multilayer ceramic chip inductor according to claim 10, wherein an organic lead compound is added as a sintering aid for the insulating layer. The method for manufacturing a multilayer ceramic chip inductor according to claim 10, wherein the silver plating pattern is provided by using a silver plating solution containing no cyan. The method of manufacturing a multilayer ceramic chip inductor according to claim 10, wherein an adhesive is not used when the electroformed conductor pattern is directly transferred to the first insulating layer. The multilayer ceramic chip inductor according to claim 10, wherein at least one pair of insulating layers has adhesiveness. The method for manufacturing a multilayer ceramic chip inductor according to claim 10, wherein the first insulating layer, the electroformed conductor pattern, and the second insulating layer are integrally sintered. The method for manufacturing a multilayer ceramic chip inductor according to claim 10, wherein a green sheet is used as the first insulating layer. A step of forming a conductor pattern on a base plate having conductivity by electroforming, and directly transferring the electroformed conductor pattern to an insulating layer, and alternately laminating a plurality of the insulating layers and the electroformed conductor pattern. A method of manufacturing a multilayer ceramic chip inductor, comprising: a step of electrically connecting the electroformed conductor patterns; and a step of integrally sintering the insulating layer and the electroformed conductor patterns. Forming a conductor pattern on a base plate having conductivity by electroforming, and forming another first insulating layer on the upper surface of the electroformed conductor pattern after transferring the electroformed conductor pattern to the first insulating layer; And a step of alternately repeating the above steps, so that the electroformed conductor patterns are electrically connected to each other.

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