JP2999357B2 - Manufacturing method of multilayer electronic component - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method useful for a multilayer electronic component such as a multilayer chip inductor, a multilayer transformer, an LC composite component and the like having a built-in multilayer conductor.

[0002]

2. Description of the Related Art As shown in FIG. 7, a multilayer electronic component of this kind, for example, a multilayer chip inductor, has unfired magnetic sheets 1 to 4 and 10 to 12 and through holes and various pattern shapes formed on the sheets. Sheets 5 to 9 formed by providing coil conductor layers P5 to P9 are prepared, stacked in a predetermined order shown on the right side of the drawing, thermocompressed, and fired.
It is manufactured by applying and baking a conductive paste to be an external electrode on the surface of the laminated chip after firing. Sheet 5
The conductor layers P5 to P9 adjacent to each other via the through-holes 8 to 8 are connected in the form of a coil through through-holes, whereby a coil conductor having a predetermined number of turns is formed in the laminated chip. In the drawings, 1
Parts corresponding to parts are shown, but each actual sheet has a size corresponding to many parts, and conductor layers etc. are formed by the number of parts acquired, and cut into parts dimensions after lamination and crimping And then fired.

The conductor layers P5 to P9 are usually formed by screen-printing a conductive paste on the upper surface of each of the sheets 5 to 9 in a predetermined pattern shape. Since the conductor layers P5 to P9 protrude by the thickness of the coil conductor, the number of turns of the coil conductor is increased to cope with an increase in inductance, or the thickness of the conductor layers P5 to P9 is increased to increase the allowable current. Attempting to cope with this will increase the component dimensions by the number of turns and the increase in thickness.

[0004] Under these circumstances, Japanese Patent Laid-Open Publication No.
No. 5 discloses an example of the solution. In the method disclosed in the publication, as shown in FIGS. 8 and 9, the conductive layer P
Are formed in advance, and a conductive paste is printed in the groove D to form the conductor layer P. According to the method, the protrusion height of the conductor layer P is increased by the depth of the groove D. Can be reduced, and the component dimensions do not increase even when the number of turns of the coil conductor is increased or when the thickness of the conductor layer P is increased.

[0005]

However, in the case where the thick film method is used for forming the conductor layer, even when the conductor layer P is formed in the groove D as described above, the entirety is accommodated in the groove D. Is impossible, and as shown in FIG.
The upper surface portion slightly protrudes from the upper surface of the sheet.

That is, when the sheets S after the formation of the conductor layer are laminated and pressed, the stress is concentrated on the contact portion of the upper sheet S with the conductor layer as shown in FIG. There is a problem that the magnetic susceptibility changes and the electrical characteristics vary. The above problem is not limited to the multilayer chip inductor, but a multilayer transformer having a built-in conductor having a similar multilayer structure, L
It can also occur in other laminated electronic components such as C composite components.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing a laminated electronic component which has stable electric characteristics and can be reduced in size. .

[0008]

In order to achieve the above object, the invention of claim 1 includes a step of forming a groove on the surface of a green sheet, and a step of forming a conductor layer in the groove by a thick film method. A method of manufacturing a laminated electronic component, comprising the steps of laminating and pressing a plurality of green sheets obtained through these steps, wherein irregularities are provided on the inner surface of the groove in the groove forming step. .

According to a second aspect of the present invention, there is provided a step of forming a groove on the surface of a green sheet, a step of forming a conductor layer in the groove by a thick film method, and a step of forming a plurality of green sheets obtained through these steps. In the method for manufacturing a laminated electronic component including the steps of laminating and crimping, the width of the groove formed in the groove forming step is larger than the width of the conductor layer formed in the conductor layer forming step. Its features.

According to a third aspect of the present invention, there is provided a process of forming a groove on the surface of a green sheet, a step of forming a conductor layer in the groove by a thick film method, and a method of forming a plurality of green sheets obtained through these steps. A method for manufacturing a laminated electronic component, comprising a step of laminating and crimping, wherein a chamfered portion is provided at a groove opening end in the groove forming step.

[0011]

According to the first aspect of the present invention, since the inner surface of the groove for receiving the conductor layer is provided with irregularities, a part of the conductor layer is caused to enter a gap formed between the irregularity on the inner surface of the groove and the conductor layer. Thus, the stress applied to the conductor layer contact portion of the sheet during crimping can be reduced, and the density of the same portion can be prevented.

According to the second aspect of the present invention, since the width of the groove for receiving the conductor layer is made larger than the width of the conductor layer, the gap formed between the widthwise surface in the groove and the conductor layer is formed. By invading a part of the conductor layer, the stress applied to the conductor layer contact portion of the sheet at the time of pressure bonding can be reduced, and the density of the portion can be prevented.

According to the third aspect of the present invention, since the chamfered portion is provided at the opening end of the groove for receiving the conductor layer, the gap between the chamfered portion at the groove opening end and the conductor layer has one side of the conductor layer. By invading the portion, the stress applied to the conductor layer contact portion of the sheet during pressure bonding can be reduced, and high density of the portion can be prevented.

[0014]

1 and 2 relate to a first embodiment of the present invention. FIG. 1 is a partial sectional view of a sheet, and FIG. 2 is a view showing a state in which a conductor layer is formed in a groove.

The sheet S is made of a slurry prepared by mixing a powder of Ni—Zn—Cu ferrite or the like with a binder, and has a thickness of about several tens μm on an upper surface of a flexible film such as PET by a doctor blade method. It is formed by coating with. On the upper surface of the sheet S, a groove D1 substantially matching the printed shape of the conductor layer is formed with a predetermined depth dimension, and a large number of irregularities D1a are provided on the inner surface of the groove D1. The shape of the uneven portion D1a may be a regular shape other than the random shape as shown in the illustrated example.

The groove D1 is preferably irradiated with a laser beam,
Specifically, a laser beam of a normal pulse oscillated from a laser light source such as a YAG laser is irradiated on a mask having a light-transmitting portion similar in shape to the conductor layer, and the light passing through the light-transmitting portion is condensed by a lens to form a sheet. An image is formed on the upper surface of S in the same shape as the conductor layer,
It is formed by melting and vaporizing the portion. The depth of the groove D1 can be adjusted by the laser light output, and the uneven portion D1a does not remove the molten residue generated at the time of laser light irradiation but leaves the groove D1 as it is, or the groove D1 is irradiated with the laser light. After the formation, it can be easily formed by, for example, a method of lightly pressing the inner surface of the groove with a mold having an uneven surface.

Although not shown, a through hole for connecting a conductor layer is formed in the sheet S so as to intersect with a part of the groove D1 as necessary. Irradiation is used.

The coil conductor layer P is formed by printing a predetermined pattern in the groove D1 by a thick film method such as screen printing using a conductive paste prepared by mixing a powder such as Ag with a binder. Have been. Sheet S
When a through hole is formed in the through hole, a conductive paste is filled in the through hole at the same time as the formation of the conductor layer. Most of the conductor layer P is received in the groove D1 and its upper surface slightly protrudes from the upper surface of the sheet S. Further, the uneven portion is provided between the conductive layer P and the uneven portion D1a on the inner surface of the groove D1. A large number of gaps E corresponding to the depressions D1a are formed.

When another sheet is laminated and pressed on the sheet S after the conductor layer is formed, a portion near the concave and convex portion of the conductor layer P penetrates into the gap E due to the pressing force, and the upper surface of the conductor layer P As a result, the stress applied to the conductor layer contact portion of the upper sheet during crimping is reduced, and the density of the portion is prevented from increasing.

According to the present embodiment, the protruding height of the conductor layer P can be reduced by the depth of the groove D1, so that the number of turns of the coil conductor can be increased to cope with an increase in inductance or the thickness of the conductor layer P can be reduced. Even if the tolerance is increased to increase the allowable current, the dimensions of the components are not increased, which can contribute to the miniaturization of the components and hardly cause the stacking misalignment during crimping.

Further, by applying a part of the conductor layer P to the gap E formed between the concave and convex portion D1a on the inner surface of the groove D1 and the conductor layer P, the stress applied to the conductor layer contact portion of the upper sheet at the time of pressure bonding. Therefore, it is possible to prevent the density of the same portion from being increased, so that it is possible to obtain a stable electric characteristic by avoiding a change in the magnetic permeability after firing.

Further, since the groove D1 is formed by removing a part of the sheet S by irradiating a laser beam, the groove bottom portion is not densified as in the case of forming the groove by pressing a mold. A change in the groove dimension due to restoration or the like can be prevented, and this can contribute to the stabilization of the characteristics.

FIGS. 3 and 4 relate to a second embodiment of the present invention. FIG. 3 is a partial sectional view of a sheet, and FIG. 4 is a view showing a state where a conductor layer is formed in a groove.

The sheet S is formed by applying the same slurry as in the first embodiment to the upper surface of the film by the doctor blade method. On the upper surface of the sheet S, a groove D2 having a larger width than the printed shape of the conductor layer is formed with a predetermined depth. The groove D2 is formed by the same laser beam irradiation as in the first embodiment, and a through hole for connecting a conductor layer is formed in the sheet S as necessary.

The coil conductor layer P is formed by printing the same conductive paste as in the first embodiment in the groove D2 in a pattern shape having a smaller width than the groove D2 by a thick film method. When a through hole is formed in the sheet S, the conductive paste is filled in the through hole at the same time as the formation of the conductor layer. Most of the conductor layer P is received in the groove D1 and its upper surface portion slightly protrudes from the upper surface of the sheet S. Further, between the conductor layer P and the widthwise surface in the groove D2, both of them are provided. A gap E is formed based on the difference in the width dimension.

When another sheet is laminated and pressed on the sheet S on which the conductor layer is formed, the crimping force causes the widthwise portion of the conductor layer P to enter the gap E and lower the upper surface of the conductor layer P. However, this reduces the stress applied to the conductor layer contact portion of the upper sheet during crimping, thereby preventing the portion from having a higher density.
In this embodiment, the same effects as in the first embodiment can be obtained.

FIGS. 5 and 6 relate to a third embodiment of the present invention. FIG. 5 is a partial sectional view of a sheet, and FIG. 6 is a view showing a state in which a conductor layer is formed in a groove.

The sheet S is formed by applying the same slurry as in the first embodiment to the upper surface of the film by the doctor blade method. On the upper surface of the sheet S, a groove D3 substantially conforming to the printed shape of the conductor layer is formed with a predetermined depth, and a curved chamfered portion D is formed at an open end of the groove D3.
3a is provided along the groove D3. Chamfer D3
The shape of a may be a tapered shape in addition to a curved shape as shown in the illustrated example. The groove D3 is formed by the same laser beam irradiation as in the first embodiment.
A through-hole for connecting the conductor layer is formed as necessary.

The coil conductor layer P is formed by printing the same conductive paste as in the first embodiment in a predetermined pattern in the groove D3 by a thick film method. When a through hole is formed in the sheet S, the conductive paste is filled in the through hole at the same time as the formation of the conductor layer. Most of the conductor layer P is received in the groove D1 and its upper surface portion slightly protrudes from the upper surface of the sheet S, and the chamfer D3a between the conductor layer P and the opening end of the groove D1 is chamfered. A gap E corresponding to the size of the portion D3a is formed.

When another sheet is laminated and pressed on the sheet S after the formation of the conductor layer, the portion near the chamfered portion of the conductor layer P penetrates into the gap E due to the compression force, and the upper surface of the conductor layer P is As a result, the stress applied to the conductor layer contact portion of the upper sheet during crimping is reduced, and the density of the portion is prevented from increasing. In this embodiment, the same effects as in the first embodiment can be obtained.

Although an example in which the present invention is applied to a multilayer chip inductor has been described above, the present invention relates to another multilayer electronic component in which a conductor layer is formed in a groove of a green sheet, for example, a multilayer transformer, an LC composite. It can be widely applied to parts and the like, and the same effect can be obtained.

[0032]

As described in detail above, according to the present invention,
Since the protruding height of the conductor layer can be reduced by the depth of the groove, the component dimensions do not increase even when the thickness of the conductor layer is increased to cope with the increase in allowable current, and it is possible to contribute to the miniaturization of components, It is unlikely to cause stacking misalignment during crimping. In addition, by injecting a part of the conductor layer formed in the groove into each gap, the stress applied to the conductor layer contact part of the sheet during crimping is reduced, preventing the same part from becoming denser, and stable electrical characteristics Can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a seat according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a state where a conductor layer is formed in a groove;

FIG. 3 is a partial sectional view of a seat according to a second embodiment of the present invention.

FIG. 4 is a view showing a state where a conductor layer is formed in a groove;

FIG. 5 is a partial sectional view of a seat according to a third embodiment of the present invention.

FIG. 6 is a view showing a state where a conductor layer is formed in a groove;

FIG. 7 is a diagram showing a manufacturing procedure of the multilayer chip inductor.

FIG. 8 is a top view of a sheet showing a conventional example.

FIG. 9 is an enlarged sectional view taken along line AA of FIG. 8;

FIG. 10 is a diagram for explaining a problem of a conventional example.

[Explanation of symbols]

S: sheet, D1, D2, D3: groove, D1a: uneven portion,
D3a: chamfer, E: gap, P: conductor layer.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-106173 (JP, A) JP-A-49-73669 (JP, A) JP-A-3-219605 (JP, A) JP-A-3-106605 153308 (JP, A) JP-A-2-63106 (JP, A) JP-A-3-116799 (JP, A) JP-A-62-172794 (JP, A) JP-A-5-112894 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) H01F 17 / 04,41 / 04 H05K 3/46

Claims (5)

(57) [Claims] 1. A step of forming a groove on the surface of a green sheet, a step of forming a conductor layer in the groove by a thick film method, and a step of laminating and pressing a plurality of green sheets obtained through these steps. The method of manufacturing a laminated electronic component, comprising :
A method for manufacturing a multilayer electronic component, wherein unevenness is provided for a part to enter . 2. A step of forming a groove on the surface of the green sheet, a step of forming a conductor layer in the groove by a thick film method, and a step of laminating and pressing a plurality of green sheets obtained through these steps. the method of manufacturing a multilayer electronic component comprising the door, the width of the groove formed in the groove forming step is made larger than the width of the conductor layer formed in the conductive layer forming step, sea
The gap for allowing a part of the conductor layer to enter during crimping
A method for manufacturing a laminated electronic component, wherein the method is formed between an inner surface and a conductor layer . 3. A step of forming a groove on the surface of the green sheet, a step of forming a conductor layer in the groove by a thick film method, and a step of laminating and crimping a plurality of green sheets obtained through these steps. the method of manufacturing a multilayer electronic component comprising the door, in Rukoto a chamfered portion is provided in the groove open end in the groove forming step,
Clear the gap for part of the conductor layer to enter during sheet crimping
A method for manufacturing a laminated electronic component, wherein the method is formed between a chamfered portion and a conductor layer . 4. The semiconductor device according to claim 1, wherein the thickness of the conductor layer formed in the conductor layer forming step is larger than the depth of the groove formed in the groove forming step. The manufacturing method of the laminated electronic component as described in the above. 5. The method according to claim 1, wherein the groove is formed by irradiating a laser beam.