JPH07142255A - Multilayer coil and its manufacture - Google Patents

Abstract

PURPOSE:To provide a product at lower costs by proposing a structure which can lower the cost of the formation of a hole in a ceramic green sheet in a multilayer coil used for various kinds of electric apparatuses. CONSTITUTION:Out of holes 13 which are formed to be perforation-shaped in ceramic green sheets 11, an electrode material is filled into only the holes which are situated in internal-electrode patterns 12, the holes are made to function as through holes, and a multilayer coil is manufactured. As a method of forming the holes 13 to be perforation-shaped in the ceramic green sheets 11, a method in which the ceramic green sheets 11 which are moved relatively are irradiated with, e.g. a pulselike laser beam is effective.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated ceramic coil component such as a chip inductor, a laminated coil or the like, or a laminated coil which is a composite component thereof, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Recently, laminated coils have been used in various electric products.

FIG. 7 shows an example of a conventional method for manufacturing a laminated coil. In FIG. 7, an internal electrode pattern 2 is formed on a ceramic green sheet 1 made of ferrite or a dielectric material, a predetermined number of layers are laminated, and then fired to form an external electrode pattern. Here, ceramic raw sheet 1
A hole 3 is formed in the hole, and the hole 3 is filled with an electrode material for through connection in advance to form a through hole, and a plurality of internal electrode patterns 2 are connected by this through hole.

FIG. 8 shows an example in which a plurality of holes 3 are formed for one internal electrode pattern 2. By forming a plurality of through holes in the internal electrode pattern 2 in this way, disconnection at the through holes is less likely to occur.

FIG. 9 shows an example in which a plurality of internal electrode patterns 2 are formed by printing on one ceramic green sheet 1. After stacking a predetermined number of the ceramic green sheets 1 on which the internal electrode patterns 2 are formed as described above, they are cut at the positions indicated by the dotted lines in FIG. 9 to form a laminated coil.

[0006]

However, in the conventional method of forming a plurality of through holes, the die cost increases as the number of through holes increases. Further, when forming holes with a laser, the processing cost increases in proportion to the number of holes. Therefore, forming a plurality of through holes for one electrode pattern has a problem in terms of cost.

The present invention is intended to solve the above-mentioned conventional problems, and aims to provide an inexpensive laminated coil by forming a plurality of through holes by forming dummy through holes at an extremely low cost. Is.

[0008]

In order to achieve this object, a laminated coil of the present invention has a structure in which internal electrode patterns having a predetermined shape are laminated so as to be connected via a plurality of ceramic green sheets, The internal electrode pattern of the laminated coil formed by cutting and firing is filled with an electrode material only in a predetermined hole among a plurality of independent holes formed in a straight line at an arbitrary pitch in the ceramic green sheet. It has a structure in which it is connected through a through hole made by the above.

[0009]

With this structure, the ceramic green sheet is located at the position of the internal electrode pattern among a plurality of independent holes (continuous holes formed in a perforated shape) linearly formed at an arbitrary pitch. Only the material can be filled with the electrode material to function as a through hole. Further, in order to form perforations in the ceramic green sheet, the holes can be formed very easily by irradiating the ceramic green sheet which moves relatively with, for example, pulsed laser light.

[0010]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of forming a laminated coil by using perforated holes formed in a ceramic green sheet as through holes. In FIG. 1, a plurality of holes 13 are formed in the ceramic green sheet 11 at regular intervals in a straight line and independently. Reference numeral 12 denotes an internal electrode pattern, and in the present invention, the internal electrode pattern 12
The electrode material (not shown) is filled only in the hole 13 located at the position where it touches and functions as a through hole. In addition, the hole 13 not located at the position of the internal electrode pattern 12 is left unfilled with the electrode material.

Next, with reference to FIGS. 2 to 4, a procedure will be described in which holes are formed in the ceramic green sheet in a perforated shape, and the holes at predetermined positions are used as through holes.
First, FIG. 2 illustrates an example of a method of forming perforations in a ceramic green sheet. In FIG. 2, 14 is an XY stage, and the ceramic green sheet 1
It is possible to move at high speed in the direction of the arrow with 1 fixed. Reference numeral 15 is a laser device, and a laser 16 is irradiated toward the ceramic green sheet 11 from its tip,
The holes 13 are formed on the surface of the ceramic green sheet 11. Here, by incorporating a Q switch in the laser device 15, pulse oscillation of about 100 to 10000 Hz becomes possible. Such Q-switches include mechanical ones and acousto-optical ones.

Thus, continuous perforated holes as shown in FIG. 3 are formed in the ceramic green sheet at equal intervals. In FIG. 3, a plurality of holes 13 are formed in a straight line in the ceramic green sheet 11 in an independent state. Next, as shown in FIG. 4, the internal electrode pattern 12 is formed on the ceramic green sheet 11 in which the continuous perforated holes 13 are formed. At this time, the hole 13 at the position of the internal electrode pattern 12 is filled with an electrode material to form a through hole. In addition, the holes 1 not located at the positions of the internal electrode patterns 12
Since 3 is not filled with the electrode material, it becomes a dummy and does not function as a through hole. The ceramic green sheets 11 thus produced are laminated as shown in FIG. 1, and then cut and fired to produce a laminated coil.

Further details will be described. First, perforated holes were formed in the ceramic green sheet with the structure as described in FIG. Here, the laser is 1000 Hz
The carbon dioxide gas laser pulse-oscillated using the Q switch was irradiated onto the ceramic green sheet 11 in a state of moving at 200 mm / sec. Then, the perforations 13 could be formed at a high speed with a pitch of 0.2 mm. Next, the internal electrode pattern 12 was formed by printing on the perforated ceramic green sheet as shown in FIG. At this time, at the same time, the holes 13 at the positions of the internal electrode patterns 12 were simultaneously filled with the electrode ink. Finally, a laminated coil was manufactured by laminating, cutting and firing so as to have a shape as shown in FIG. Here, when the length of each product in the perforation direction was 2 mm, several through holes could be formed for one internal electrode pattern 12. By making holes while moving the ceramic green sheet at 200 mm / sec, several through holes could be formed at a speed equivalent to 100 / sec in terms of product.

A higher speed Q switch can be used. For example, at 10 KHz,
Holes can be formed at a high speed in a straight line at a pitch of 0.2 mm even on a ceramic green sheet that is moving at a high speed of 2000 mm / sec.

Here, the pitch does not have to be 0.2 mm. In the case of the present invention, at least one hole functioning as a through hole may be formed in the internal electrode pattern 12. Thus, the pitch is the internal electrode pattern 12
The line width, the length of the internal electrode pattern, the size of the product, the size of the laser hole, etc. can be optimized. Further, the oscillation frequency of the laser and the moving speed of the ceramic green sheet may be synchronized. If the tuning is not performed, it is necessary to increase the pulse of the laser so that at least one hole is formed in the internal electrode pattern or reduce the moving speed of the ceramic green sheet.

For comparison, a conventional laser green sheet was punched with a conventional laser. This was performed by fixing a ceramic green sheet to an XY stage, moving it to a predetermined position to form one hole, and moving it to a predetermined position to perform punching a predetermined number of times. As described above, in the conventional case, the XY stage repeats fine movements, and several holes / second is the limit for speeding up.

(Example 2) Next, as Example 2, an example of punching holes in a ceramic green sheet in the case of improving the stacking property will be described. FIG. 5 is an example of punching with improved stackability. By stacking the ceramic green sheets 11 on which the internal electrode patterns 12 shown in FIG. 5 are formed by alternately moving electrode pitches in the arrow direction. The laminated body shown in FIG. 1 can be easily formed.

A more detailed description will be given. First, a ferrite green sheet was used as the ceramic green sheet. This ferrite green sheet was obtained by applying a ceramic material mainly composed of ferrite to a thickness of 100 μm on a base film. Next, this ferrite raw sheet is XY
It is fixed to the stage and this XY stage is reciprocated,
Perforation-like holes were formed by continuously irradiating a laser on this. Here, the laser is 100W output 3
A YAG laser with a 00 Hz Q-switch was used.
Here, when the XY stage was moved at a speed of 100 mm / sec, one perforated hole was formed at a pitch of 0.33 mm.
It was possible to form 300 pieces per second. Even if 6 holes are used for one component area, it is 50 in terms of product.
It was possible to drill holes at a rate of pieces / second.

Next, an internal electrode pattern was printed on the green ferrite sheet having continuous holes. Here, the electrode ink was made of 100% silver, and the electrode ink was also filled in the perforated holes in the portion corresponding to the internal electrode pattern. In this way, a predetermined number of ceramic green sheets corresponding to FIG. 5 were prepared, laminated in the shape shown in FIG. 1, cut, fired, and external electrodes were formed.

Thus, a 2125 type laminated coil was formed, and its characteristics were measured.
The impedance at 0 MHz was 1000Ω or more, and it was found that the noise filter has sufficient characteristics.

For comparison, the same ferrite raw sheet as the conventional example was formed with one hole using a laser, an electrode pattern was printed in the same manner, and lamination, cutting, firing and external electrode formation were performed. However, it was possible to make holes only for a few products per second. From the above, by using the hole drilling method according to the present embodiment, productivity of 10 times or more was obtained.

(Embodiment 3) As Embodiment 3, an example of further increasing the speed of forming perforated holes in the green ceramic sheet will be described with reference to FIG. In FIG. 6, 17 is a drum, which rotates in the direction of the arrow.
By spirally winding the ceramic green sheet 11 around the surface of the drum 17, the ceramic green sheet 11 is continuously fed by the rotation of the drum 17.

By winding the ceramic green sheet 11 around the drum 17 as described above, high-speed hole drilling can be performed on a continuous ceramic green sheet.

(Embodiment 4) As Embodiment 4, an example of using a galvanometer for forming perforated holes in a ceramic green sheet will be described. Here, as the galvanometer, a galvanometer which has been put into practical use by trimming a chip resistor or the like and whose laser power is increased was used.

For comparison, as an example of hole formation using a conventional galvanometer, positioning was performed each time one hole was formed by the galvanometer. However, it was extremely difficult to obtain the positional accuracy of each hole. Furthermore, when the area of the ceramic green sheet was 150 mm square or more, the hole positioning accuracy was poor and it could not be put to practical use.

However, in the case of Example 4, it is sufficient to form perforated holes in the ceramic green sheet, and even if the area of the ceramic green sheet is 200 mm square or more, the positional accuracy of the holes is not deteriorated. Further speedup was also easy.

In the embodiment, the perforated holes located in the internal electrode pattern are filled with the electrode material. Further, the perforated holes which are not located in the internal electrode pattern are left as they are. In this case, small independent holes are formed inside after firing, but there is no problem with reliability or the like. Further, it is possible to further improve the characteristics by filling the perforated holes which are not located in the internal electrode pattern with the ceramic material. Even if the perforated holes that are not located in the internal electrode pattern are filled with the electrode material, in the case of the present invention, it hardly causes the interlayer short circuit.

When forming holes with a laser, the ceramic green sheet may be processed together with the base film. At this time, the holes can be formed only in the ceramic green sheet portion without forming the holes in the base film depending on the power of the laser, how to apply the air, and the kind of the laser. In the present invention, when the holes are not formed in the base film, the amount of electrodes filled in the through holes can be reduced, which is effective in cost reduction.

Further, even when a rotating mirror or the like is used instead of the galvanometer, the perforated holes can be similarly formed at high speed.

[0030]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, a laminated coil formed by laminating internal electrode patterns of a predetermined shape so as to be connected via a plurality of ceramic green sheets, and then cutting and firing the laminated coil. The internal electrode pattern is connected through a through hole formed by filling an electrode material only in a predetermined hole among a plurality of independent holes linearly formed in the ceramic green sheet at an arbitrary pitch. With such a configuration, the hole workability can be increased, and a lower cost laminated coil can be realized.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an example in which a laminated coil is formed by using perforated holes formed in a ceramic green sheet in a first embodiment of the present invention as through holes.

FIG. 2 is a perspective view illustrating an example of a method of forming perforations in a ceramic green sheet in the present invention.

FIG. 3 is a perspective view illustrating a manner of forming continuous perforated holes in a ceramic green sheet at equal intervals in the present invention.

FIG. 4 is a perspective view illustrating a manner of forming internal electrode patterns on a ceramic green sheet having continuous perforated holes according to the present invention.

FIG. 5 is a perspective view illustrating a state in which ceramic green sheets having internal electrode patterns are laminated in a second embodiment of the present invention.

FIG. 6 is a perspective view illustrating an example of further increasing the rate of forming perforated holes in the ceramic green sheet according to the third embodiment of the present invention.

FIG. 7 is a perspective view illustrating an example of a conventional laminated coil manufacturing method.

FIG. 8 is a perspective view illustrating an example in which a plurality of holes are formed for one electrode pattern in the conventional method.

FIG. 9 is a perspective view illustrating an example in which a plurality of coil patterns are formed by printing on a conventional single ceramic green sheet.

[Explanation of symbols]

 11 Ceramic Raw Sheet 12 Internal Electrode Pattern 13 Hole 14 XY Stage 15 Laser Device 16 Laser 17 Drum

Claims (6)

[Claims] 1. A laminated coil formed by stacking internal electrode patterns of a predetermined shape so as to be connected via a plurality of ceramic green sheets, and then cutting and firing the internal electrode patterns, A laminated coil in which a ceramic green sheet is connected through a through hole formed by filling an electrode material in a predetermined hole among a plurality of independent holes formed in a straight line at an arbitrary pitch. 2. A ceramic green sheet in which a plurality of independent holes are formed in a straight line is filled with an electrode material at a position of an internal electrode pattern of the hole to form a through hole, and then the ceramic green sheet is formed. A method for manufacturing a laminated coil, comprising laminating a predetermined number of sheets, cutting and firing. 3. A ceramic green sheet that moves at a predetermined speed is irradiated with a laser pulse to form a plurality of independent holes in a straight line at a predetermined pitch, and then the ceramic green sheet has a plurality of holes above the holes. A method of manufacturing a laminated coil, comprising forming internal electrode patterns so that at least one or more holes are through holes, laminating a predetermined number of the ceramic green sheets, and cutting and firing. 4. A rotating ceramic green sheet is irradiated with a laser pulse to form a plurality of independent holes in a straight line at a predetermined pitch, and then the ceramic green sheet is provided with internal electrodes on the plurality of holes. A method for producing a laminated coil, comprising forming a pattern so that at least one hole is a through hole, laminating a predetermined number of the ceramic green sheets, cutting and firing. 5. A ceramic green sheet is irradiated with a laser pulse from a laser device through a galvanometer or a rotating mirror to form straight linear independent holes at a predetermined pitch, and then a plurality of the ceramic green sheets are formed on the ceramic green sheet. A method of manufacturing a laminated coil, comprising forming an internal electrode pattern on a hole so that at least one hole becomes a through hole, laminating a predetermined number of the ceramic green sheets, cutting and firing. 6. A ceramic green sheet in which a plurality of independent holes are formed in a straight line is formed at a position of an internal electrode pattern of the hole with an electrode material to form a through hole, while the inside of the hole is formed. A method for manufacturing a laminated coil, in which a ceramic material is filled in a material that is not located at an electrode pattern, a predetermined number of the ceramic green sheets are laminated, and then cut and fired.