JP2001085244A - Laminated chip inductor and its manufactre - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a laminated chip inductor which is compact and excellent in high-frequency characteristic, can reduce the manufacturing cost, and is suited to chip mounting dealing with a bulk, and its manufacturing method. SOLUTION: This laminated chip inductor is formed by laminating conductor patterns vertically and forming a coil-like inner conductor of the conductor patterns. In this case, conductor patterns 11 and 21 between respective layers are formed by more than one round so that outer circumference ends 12 and 22 and inner circumference ends 13 and 23 may reach a straight line connecting an axial center with a peripheral part, and, in the conductor patterns 11 and 21 located vertically, the outer circumference ends 12 and 22 and outer circumference ends 13 and 23 are electrically connected with each other alternately and respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer chip inductor and a method of manufacturing the same, and more particularly, to a multilayer chip inductor which can be surface-mounted by using a rectangular bulk chip mounter and a method of manufacturing the same.

[0002]

2. Description of the Related Art A so-called bulk-compatible chip mounter in which a large number of chip parts are housed in a cartridge and these chip parts are surface-mounted one by one on a printed circuit board or the like is becoming widespread. As a chip component suitable for such a chip mounting and functioning as an inductance element, a conductor pattern is formed on a green sheet made of a magnetic ceramic or the like, and one end of the conductor pattern is formed on the green sheet conductor pattern positioned above. At the end, the other end of the conductor pattern of the green sheet positioned below is laminated in a multilayer structure while being electrically connected to each other, thereby forming a coil-shaped internal conductor with the conductor pattern. A multilayer chip inductor in which an external electrode is electrically connected to an end of a conductor is generally known.

In this kind of multilayer chip inductor,
The conductor pattern is divided by 1 /
For example, it is formed by printing a paste mainly composed of Ag or Ag-Pd on a green sheet so as to extend over two or three quarters of the circumference. And 1 /
A predetermined number of green sheets are formed by rotating the conductor pattern by 180 ° in a two-circle conductor pattern, and by rotating the conductor pattern by 90 ° in one direction in a ／ conductor pattern. Laminated up and down to form a coiled internal conductor.

[0004]

However, in the above-described multilayer chip inductor, the number of turns of the conductor pattern formed by one printing on the green sheet is reduced to 1 /.
Since it is 2 or 3/4, especially in order to respond to recent demands for downsizing and weight reduction, it is necessary to stack a larger number of green sheets in order to obtain a high L value by increasing the number of turns of the coil. In addition to the increase in the number of printing steps (the number of times) and the increase in the lead time, there has been a problem that the thickness of the spiral forming portion increases accordingly, and the floating capacitance of the external terminal and the internal spiral increases.

A spiral conductive pattern is formed inside the green sheet, and the spiral conductive pattern is electrically connected at the center or the peripheral portion of the green sheet. Although a structure in which a conductor is formed has been proposed, in this case, the magnetic flux penetrates the conductor pattern itself, and high-frequency characteristics such as a self-resonant frequency and a Q value are deteriorated due to eddy current loss generated therein. In addition, since the conductor pattern is wound up to the inside of the core diameter, it occupies a wider area.

The present invention has been made in view of the above circumstances, and provides a multilayer chip inductor suitable for bulk-compatible chip mounting, which is small in size, has good high-frequency characteristics, and can reduce the manufacturing cost, and a method for manufacturing the same. The purpose is to:

[0007]

According to a first aspect of the present invention, there is provided a multilayer chip inductor in which a conductor pattern is laminated in a vertical direction to form a coil-shaped internal conductor with the conductor pattern. The outer peripheral end and the inner peripheral end are formed over one or more turns so as to reach a straight line connecting the axis and the peripheral part, and the upper and lower conductor patterns are formed by the outer peripheral end or the inner peripheral end. A multilayer chip inductor characterized by being electrically connected alternately.

According to the present invention described above, a conductor pattern extending over one or more turns is formed between the layers, and the conductor patterns are electrically connected to form a coil-shaped internal conductor. By maximizing the area, a higher L value can be obtained with a smaller number of layers,
It can meet the demand for miniaturization and high frequency.

According to a second aspect of the present invention, the conductive pattern is formed in a shape based on a circle or in a rectangular shape with rounded corners. It is a multilayer chip inductor of the above description. As a result, current concentration at high frequencies can be reduced, and high-frequency characteristics can be improved.

According to a third aspect of the present invention, the conductive pattern is formed on the surface of the base material, and is located at the outer peripheral end or the inner peripheral end of the base, and bisects the corner of the corner. 3. The multilayer chip inductance according to claim 1, wherein the multilayer chip inductance is electrically connected via a through hole provided on a line extending along the line. As a result, a conductor pattern that makes the most of the limited area is formed.

According to a fourth aspect of the present invention, two types of conductor patterns over one or more turns are wound in the same winding direction so that the outer peripheral end and the inner peripheral end reach a straight line connecting the center and the peripheral part on the surface. Characterized in that two kinds of green sheets are prepared and the two kinds of green sheets are alternately laminated while being electrically connected alternately at outer peripheral ends or inner peripheral ends. It is a manufacturing method of. Thus, by laminating green sheets having basically two types of conductor patterns, it is possible to produce a small-sized, bulk-compatible multilayer chip inductor having good characteristics with good productivity at low cost.

According to a fifth aspect of the present invention, in laminating two types of green sheets on which the two types of conductor patterns are formed, the two types of conductor patterns are arranged in at least one of the row and column directions for each chip. 2. A green sheet having a large area formed alternately, wherein two types of green sheets which are shifted by one pitch in the direction formed alternately are prepared, and the green sheets are alternately laminated. 5. A method of manufacturing the multilayer chip inductor according to 4. Thereby, two types of green sheets having a large area having two types of conductor patterns can be formed by printing using the same plate making while shifting the printing position.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an exploded perspective view showing a state before lamination of a multilayer chip inductor according to a first embodiment of the present invention. FIG. 2 is a diagram showing two basic types of coil inductors used in FIG. FIG. 4 is a plan view showing a typical green sheet.

As shown in FIG. 1, an insulating first green sheet 10 made of, for example, magnetic ceramics or the like,
Similarly, a predetermined number of the second green sheets 20 are alternately laminated, and green sheets 30 for fine adjustment of the L value are provided on both front and back surfaces as needed, and green sheets 40 for external electrodes are further provided on both front and back faces. By sequentially laminating, compressing, and firing, a laminated chip inductor having a substantially square cross section is formed.

As shown in FIG. 2A, a conductor pattern 11 extending in one direction based on a circle centered on the center O of the green sheet 10 is formed inside the first green sheet 10, for example, Ag. Alternatively, it is formed by printing a conductive paste containing Ag-Pd as a main component. That is,
This conductor pattern 11 has an outer peripheral end 12 extending tangentially along one side of the green sheet 10 from the circumferential direction,
An inner peripheral end 13 extends inward from the circumferential direction in parallel with the outer peripheral end 12. The outer peripheral end 12 and the inner peripheral end 13 correspond to the center O and the corner E of the green sheet 10.
, So that the conductor pattern 11 extends over one or more rounds. In the outer peripheral end portion 12, a through hole 14 is located at a position closest to the corner within the allowable design range, that is, on a line connecting the corner O and the center O, which is a bisector of the corner of the corner E. Is provided.

On the other hand, inside the second green sheet 20, as shown in FIG. 2B, a conductor pattern 21 extending in one direction based on a circle centered on the center O of the green sheet 20 is provided. For example, it is formed by printing a conductive paste containing Ag or Ag-Pd as a main component. That is, the conductor pattern 21 is formed on the outer peripheral end 2 extending tangentially along one side of the green sheet 20 from the circumferential direction.
2 and an inner peripheral end 23 extending inward from the circumferential direction in parallel with the outer peripheral end 22. The outer peripheral end 22 and the inner peripheral end 23 reach a line connecting the center O and the corner E of the green sheet 20, whereby the conductor pattern 21 extends over one or more rounds. ing. The inner peripheral end 23 is located on a line connecting the corner O and the center O, which is a bisector of the corner of the corner E, in accordance with the through hole 14 provided in the first green sheet 10. And a through hole 24 is provided. Thereby, the conductor patterns 11 and 21 utilizing the limited area to the maximum are formed.

Here, the conductor pattern 11 of the first green sheet 10 and the conductor pattern 21 of the second green sheet 20 are wound in the same direction, that is,
In this example, the conductor pattern 11 of the first green sheet 10 is wound rightward from the inner peripheral end 13 toward the outer peripheral end 12, and the conductor pattern 21 of the second green sheet 20 is It is wound rightward from 22 toward the inner peripheral end 23.

Thus, when the second green sheets 20 are vertically stacked with the first green sheet 10 interposed therebetween, the second green sheet 20 positioned above and the conductor patterns 11 of the first green sheet 10, 21 is the second green sheet 2 at the inner peripheral ends 13 and 23 thereof.
The conductive patterns 11 and 21 of the first green sheet 10 and the second green sheet 20 located below are electrically connected to each other at the outer peripheral ends 12 and 22 thereof. , First green sheet 1
0 through the through-holes 14 provided in the coil 0 to form a coil-shaped inner conductor wound rightward in the stacking direction (vertical direction).

As described above, the conductor patterns 11 and 21 over one or more turns are formed inside the first green sheet 10 and the second green sheet 20, and the upper and lower conductor patterns 11 and 21 are connected to the outer peripheral end. By forming the coil-shaped internal conductor by alternately electrically connecting the inner peripheral portions 12, 22 or the inner peripheral end portions 13, 23, the effective area for pattern formation is maximized, and the number of layers is higher with a smaller number of layers. An L value can be obtained, which can meet the demand for miniaturization and high frequency. Also, the conductor pattern 11 based on a circle,
By forming the coil-shaped internal conductor 21, the concentration of current can be reduced and the high-frequency characteristics can be improved.

Inside the green sheet 30 for fine adjustment of the L value, there is formed a conductor pattern 31 extending in a hook shape along two sides and having rounded corners, and a through hole is formed at an end of the conductor pattern 31. 32 are provided. As a result, the conductor pattern 11 of the first green sheet 10 or the conductor pattern 21 of the second green sheet 20 and the conductor pattern 31 of the L value fine adjustment green sheet 30 are electrically connected to each other through the through hole 32. It is designed to conduct.

A through hole 41 is provided at a corner of the external electrode green sheet 40 at a position facing an end of the conductor pattern 31 of the L value fine adjustment green sheet 30.

Then, a plurality of first and second green sheets 10 and 20, an L value fine adjustment green sheet 30,
30 and the external electrode green sheets 40, 40 are sequentially laminated and pressed, and then fired to produce a laminated chip inductor, whereby the green sheets 10, 20 having basically two types of conductor patterns are laminated. By doing so, it is possible to manufacture a small-sized, bulk-compatible multilayer chip inductor having good characteristics with good productivity and at low cost.

Here, when the first green sheet 10 is represented by a symbol a and the second green sheet 20 is represented by a symbol b, a and b are lined (horizontally) as shown in FIG. A green sheet 60a having a large area alternately formed for each chip in the direction, and a and b are similarly formed alternately for each chip in a row (lateral) direction, and a and b are formed for the green sheet 60a. A green sheet 60b shifted in the row (horizontal) direction by one pitch is prepared.
a and b, that is, the first green sheet 10 and the second green sheet 20 are alternately laminated.
Can be alternately stacked. In this case, two types of green sheets 60a and 60b having a large area having the first green sheet 10 and the second green sheet 20 are provided.
Can be formed by shifting the printing position using the same plate making.

As shown in FIG. 3B, a green sheet 70a having a large area in which a and b are alternately formed at every pitch in both the row (horizontal) direction and the column (vertical) direction is used. In this case, similarly to the green sheet 70a, a and b are alternately formed for each chip in both the row (horizontal) direction and the column (vertical) direction, and a and b are applied to the green sheet 70a. A green sheet 70b shifted in the row (horizontal) direction or the column (vertical) direction by one pitch is prepared, and the green sheets 70a and 70b are alternately stacked to obtain a
And b, that is, the first green sheets 10 and the second green sheets 20 can be alternately stacked.

FIG. 4 is a perspective view showing a state before lamination of the multilayer chip inductor according to the second embodiment of the present invention.
5 is a plan view showing two types of basic green sheets used in FIG. 4 to form a coiled internal conductor. FIG.

In this example, the first green sheet 10a has a square shape along this outer shape and has rounded corners, and the outer peripheral end 12a and the inner peripheral end 13a are center O and corner E And a conductor pattern 11a having a through hole 14a formed in 12a at the outer peripheral end thereof is formed as a second green sheet 20a. The conductor pattern 21a having the outer peripheral end 22a and the inner peripheral end 23a reaching the line connecting the center O and the corner E and having the through-hole 24a in the inner peripheral end 23a is formed. Used. Further, in this example, a green sheet having a through hole 41a at the center is used as the external electrode green sheet 40a, and the external electrode green sheet 40a and the first green sheet 10a are used.
Alternatively, a third green sheet 50 in which a conductor pattern 51 extending from the center to the corner portion is formed between the second green sheet 20a and a through hole 52 at one end of the conductor pattern 51 is provided. Have been placed.

As described above, by forming the coil-shaped internal conductor with the square-shaped conductor patterns 11a and 21a having rounded corners, the conductor pattern based on the circle in the first embodiment can be used. Similarly, the concentration of current can be reduced, and high-frequency characteristics can be improved.

FIG. 6 is a plan view showing two types of basic green sheets used in the multilayer chip inductor according to the third embodiment of the present invention to form a coiled internal conductor. In this example, the first green sheet 10b has a rectangular shape along the outer shape, and has semicircular rounds at both ends, and the outer peripheral end 12b and the inner peripheral end 13b are formed at the corners of the corner E. And reaches 12 on the outer peripheral end
b formed with a conductor pattern 11b provided with a through hole 14b as a second green sheet 20b.
It has a rectangular shape along this outer shape, and has a semicircular radius at both ends, and has an outer peripheral end 22b and an inner peripheral end 23b.
Reaches on the bisector E-L of the corner E and 23b
In this example, a conductor pattern 21b provided with a through hole 24b is used.

As described above, since the coil-shaped inner conductor is formed by the conductor patterns 11b and 21b having a rectangular shape and a semicircular radius at both ends, the current concentration can be increased in the same manner as in the above embodiments. And the high frequency characteristics can be improved.

In the above embodiment, an example in which the chip-type inductor element is manufactured by the green sheet method has been described. However, it goes without saying that the gist of the present invention can be similarly applied to, for example, a printing method.

[0031]

As described above, according to the present invention, a conductor pattern extending over at least one circumference is formed between each layer, and this conductor pattern is electrically connected to form a coil-shaped internal conductor. By doing so, a higher L value can be obtained with a smaller number of layers by maximizing the effective area for pattern formation, and it is possible to meet the demand for miniaturization and higher frequency. This allows
It is possible to easily manufacture a small-sized multilayer chip inductor that is suitable for so-called bulk-compatible chip mounting and has good frequency characteristics, can reduce the manufacturing cost, and can shorten the lead time.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state before lamination of a multilayer chip inductor according to a first embodiment of the present invention.

FIG. 2 is a plan view showing two types of basic green sheets used in FIG.

FIG. 3 is a diagram attached to a description of stacking two types of basic green sheets.

FIG. 4 is a perspective view showing a state before lamination of a multilayer chip inductor according to a second embodiment of the present invention.

FIG. 5 is a plan view showing two types of basic green sheets used in FIG. 4;

FIG. 6 is a plan view showing a basic green sheet of a type used to form a coiled internal conductor used in the multilayer chip inductor according to the third embodiment of the present invention.

[Explanation of symbols]

 10, 10a, 10b 1st green sheet 11, 11a, 11b same, conductor pattern 12, 12a, 12b same, outer peripheral end 13, 13a, 13b same, inner peripheral end 14, 14a, 14b same, through hole 20 , 20a, 20b Same as second green sheet 21, 21a, 21b, Same as conductive pattern 22, 22, a, 22b, Same as outer peripheral end 23, 23a, 23b, Same as inner peripheral end 24, 24a, 24b, Through hole 30L Green sheet for value fine adjustment 31 Same as conductor pattern 32 Same as through hole 40, 40a External electrode green sheet 41, 41a Same as through hole 50 Third green sheet 51 Same as conductor pattern 52 Same as through hole

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[Procedure amendment]

[Submission date] January 17, 2000 (2000.1.1)
7)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

Claims (5)

[Claims] 1. A multilayer chip inductor in which a conductor pattern is laminated in the vertical direction to form a coil-shaped internal conductor with the conductor pattern, wherein the conductor pattern between the respective layers has an outer peripheral end and an inner peripheral end which are aligned with an axis. It is formed over one or more rounds so as to reach a straight line connecting the peripheral parts, and the conductive patterns located vertically are alternately electrically connected between outer peripheral ends or between inner peripheral ends. Chip inductor. 2. The multilayer chip inductor according to claim 1, wherein the conductor pattern is formed in a shape based on a circle or in a rectangular shape with a rounded corner. 3. The conductor pattern is formed on a surface of a substrate, and is located on the outer peripheral end or the inner peripheral end of the substrate and extends on a line extending along a bisector of a corner of a corner. The multilayer chip inductance according to claim 1, wherein the multilayer chip inductance is electrically connected through the provided through holes. 4. Two types of green formed in one or more turns in the same winding direction so that the outer peripheral end and the inner peripheral end reach a straight line connecting the center and the peripheral part on the surface. A method for manufacturing a laminated chip inductor, comprising preparing sheets and alternately laminating these two types of green sheets while electrically connecting the outer peripheral ends or the inner peripheral ends alternately. 5. A method according to claim 2, wherein said two types of conductor patterns are formed.
A green sheet having a large area in which the two types of conductor patterns are alternately formed for each chip in at least one of the row and column directions when laminating the types of green sheets, and one pitch is formed in the alternately formed direction. 5. The method for manufacturing a multilayer chip inductor according to claim 4, wherein two types of green sheets shifted by an amount are prepared, and the green sheets are alternately stacked.