JP2001060518A - Laminated electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated electronic component which has high production yield and a large transverse rupture strength. SOLUTION: This electronic component is formed by laminating a magnetic sheet 21, in which a conductor pattern 24 for coil formation is printed and a magnetic sheet 21 in which a conductor pattern 22 for leading out to connect a coil with an outer electrode via a through-hole in the lamination direction is printed, and a conductor pattern 23 for relaxing stress is formed in the magnetic sheet 21 with the printed conductor pattern 22 so as to relaxing stress in the laminate. Thus, when the magnetic sheet 21 is laminated and press-fitted, stress is absorbed by the conductor pattern 23, and the stress will not concentrate in the periphery of the conductor pattern 22. Therefore, the deformation of the external shape of the laminate due to concentration of stress, or the deformation of laminating structure of the laminate can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multilayer electronic component such as a multilayer inductor and a multilayer capacitor.

[0002]

2. Description of the Related Art A multilayer inductor will be described as an example of a conventional multilayer electronic component with reference to FIGS. FIG.
7 is a cross-sectional view of a conventional laminated inductor, FIG. 7 is an exploded perspective view illustrating a laminated structure of the conventional laminated inductor, and FIG. 8 is a diagram illustrating a magnetic sintered body in the conventional laminated inductor.

As shown in FIG. 6, a laminated inductor 100 has a substantially rectangular parallelepiped magnetic sintered body 101 in which an internal electrode 102 is embedded, and a longitudinal direction of the magnetic sintered body 101 (in FIG. And) a pair of external electrodes 103 formed at both ends and connected to the internal electrodes 102. The internal electrode 102 includes a coil part 102b formed in a coil shape, and a lead part 102a arranged on the center axis of the coil and connecting one end of the coil part 102b to the external electrode 103.

The magnetic sintered body 101 is manufactured by laminating and pressing a plurality of magnetic sheets on which a conductor pattern is printed in a direction of connecting the external electrodes 103, and firing the laminated body. Specifically, as shown in FIG. 7, a magnetic sheet 111 on which a coil conductor pattern 122 forming the coil portion 102b of the internal electrode 102 is printed, and a lead conductor forming the lead portion 102a of the internal electrode 102 It has a structure in which a magnetic sheet 111 on which a pattern 121 is printed is laminated. The lead-out conductor pattern 121 is formed in a land shape near the center of the sheet for connection to the upper and lower magnetic sheets 111 through through holes. The coil conductor pattern 122 is formed in a substantially U-shape so as to be spiral by connecting through a through hole.

[0005] In such a laminated inductor 100, the stray capacitance between the patterns in the coil portion 101b is reduced, so that good high-frequency characteristics can be obtained. Also,
In the multilayer inductor 100, when mounted on a circuit board, variation in characteristics due to a difference in mounting direction is reduced. That is, there is an advantage that non-directionality at the time of mounting can be realized.

[0006]

However, the conventional laminated inductor 100 has a structure in which the buried coil portion 102b is drawn out to the end face of the magnetic sintered body 101 and connected to the external electrode 103. Has a structure in which the lead-out portion 102a becomes longer. This internal electrode 102
Has a structure in which through-holes are connected in the stacking direction, as described above. For this reason, when the magnetic sheets 111 are stacked and pressed, the magnetic sintered body 1
01 may protrude (see FIG. 8A), or the lamination state of the internal electrodes 102 may be extremely deteriorated (see FIG. 8B). This is because stress concentrates around the through hole. Further, in some cases, stress remaining around the through hole may cause a reduction in bending strength. As a result, it has been difficult to improve the production yield of the conventional multilayer inductor.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laminated electronic component having a good production yield and high bending strength.

[0008]

In order to achieve the above object, according to the present invention, a plurality of insulating sheets on which a conductor pattern is printed are laminated so that the conductor patterns are connected to each other through through holes. In the multilayer electronic component including the multilayer body and the external electrodes formed at both ends in the stacking direction of the multilayer body, the conductor pattern is formed through an element conductor pattern forming an electric element and a through hole. A lead conductor pattern connected to the electrical element and an external electrode connected in a stacking direction, and the insulating sheet on which the lead conductor pattern is formed has a stress relaxation for relaxing stress in the laminate. The invention is characterized in that a member for use is formed.

According to the present invention, when laminating and crimping the insulating sheets, stress does not concentrate around the lead-out conductor patterns connected in the laminating direction via the through holes.
That is, since the stress relaxation member is formed on the insulating sheet on which the lead conductor pattern is formed, the stress is absorbed by the stress relaxation member. Thereby, deformation of the outer shape of the laminated body due to concentration of stress and deformation of the laminated structure of the laminated body can be prevented. Further, since no stress remains in the laminate, the bending strength is also improved.

[0010] As a preferred embodiment of the present invention, according to a second aspect, in the laminated electronic component according to the first aspect, the stress relaxation member is formed on a peripheral edge of an insulating sheet. Suggest something.

According to a third aspect of the present invention, in the multilayer electronic component according to any one of the first to second aspects, the stress relaxation member is formed to have the same thickness as the lead-out conductor pattern. Suggest something.

According to a fourth aspect of the present invention, in the laminated electronic component according to any one of the first to third aspects, the stress relaxation member is formed of a conductor, is exposed on a side surface of the laminate, and is formed on the side surface. The present invention proposes a device characterized in that it is connected to an external electrode formed by wrapping around.

According to a fifth aspect of the present invention, in the multilayer electronic component according to any one of the first to fourth aspects, the stress relaxation member is formed of the same material as the lead conductor pattern. Suggest something.

Further, a sixth aspect of the present invention proposes the multilayer electronic component according to any one of the first to fifth aspects, wherein the electric element includes an inductor element.

According to the second to sixth aspects of the present invention, the stress generated in the laminate can be reliably absorbed by the stress relaxation member without being concentrated around the lead-out conductor pattern. Further, in the invention of claim 4, in particular, since the stress relaxation member is exposed to the side surface of the multilayer electronic component and is connected to the external electrode, the adhesive strength of the external electrode to the multilayer body can be improved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A laminated electronic component according to an embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a multilayer inductor having an inductor element will be described as an example of a multilayer electronic component.
FIG. 1 is a cross-sectional view of a laminated inductor, FIG. 2 is an exploded perspective view of a laminated body illustrating a laminated structure of the laminated inductor, and FIG. 3 is a plan view of a magnetic sheet illustrating a conductor pattern for stress relaxation.

As shown in FIG. 1, the laminated inductor 10 has a substantially rectangular parallelepiped magnetic sintered body 11 in which an internal electrode 12 and a stress relaxing electrode 13 forming a coil are embedded.
External electrodes 14 are formed at both ends in the longitudinal direction of the magnetic sintered body 11 and are electrically connected to the internal electrodes 12.

The magnetic sintered body 11 is formed by laminating a plurality of magnetic sheets 21 as insulating sheets and firing the laminated body. The laminating direction of the magnetic material sheet 21 is a direction connecting the pair of external electrodes 14 (in FIG. 1, a left-right direction on the paper).
It has become. That is, when the laminated inductor 10 is mounted on a circuit board, the magnetic sheets 21 are formed so that the laminating direction is parallel to the circuit board. The magnetic sintered body 11 preferably has a high magnetic permeability, for example, ferrite. Specifically, for example, Ni-Zn-C
u ferrite, Ni-Zn ferrite, Cu-Zn ferrite, and the like. In this embodiment mode, Ni—Zn—
The internal electrode 12 buried in the magnetic sintered body 11 using Cu ferrite includes a lead portion 12a exposed at both end surfaces of the magnetic sintered body 11, and a coil portion 12b connected to the lead portion 12a. The lead portion 12a is formed by connecting a plurality of through holes in the laminating direction, and is formed on or around the central axis of the coil. Internal electrode 1
2 has a low resistance value in order to realize a high Q (quality factor) as an inductor element. For example, A
The conductive member may be a precious metal containing g, Au, Pt or the like as a main component or an alloy thereof, or a base metal such as Cu or Ni or an alloy thereof. In this embodiment, Ag is used.

The stress relaxing electrode 13 buried in the magnetic sintered body 11 is a member for relaxing the stress generated when the magnetic sheets 21 are laminated. The stress relaxing electrode 13 is formed on the same laminated surface as the lead portion 12 a of the internal electrode 12. The stress relaxing electrode 13 is exposed on the side surface of the magnetic sintered body 11 and is connected to an external electrode 14 formed from the end surface to the side surface of the magnetic sintered body 11. Further, the stress relaxing electrode 13 has the same composition and thickness as the internal electrode 12.

The structure of the magnetic sintered body 11 will be described more specifically with reference to FIGS. As shown in FIG. 2, the magnetic sintered body 11 is provided with a lead portion 12 a of the internal electrode 12.
And a coil portion 12b of the internal electrode 12 on which a lead-out conductor pattern 22 forming the electrode and a stress relaxation conductor pattern 23 forming the stress relaxation electrode 13 are printed.
Is formed by laminating the magnetic material sheet 21 on which the coil conductor pattern 24 forming the above is printed. Each of the conductor patterns 22 to 24 is formed by applying a common conductive paste mainly containing Ag or the like.

As shown in FIG. 3, the lead conductor pattern 22 is formed in a land shape at a substantially central portion of the magnetic sheet 21. The lead-out conductor pattern 22 is connected to the lead-out conductor pattern 22 of the adjacent magnetic material sheet 21 via a through-hole to form the lead-out portion 12 of the internal electrode 12.
a is formed.

As shown in FIG. 3, the conductor pattern 23 for stress relaxation is formed on the magnetic sheet 21 on which the conductor pattern 22 for extraction is formed. The conductor pattern 23 for stress relaxation is formed in an annular shape around the conductor pattern 22 for extraction, and its edge is formed as far as the edge of the magnetic sheet 21. The stress-relief conductor pattern 23 is formed to have the same thickness as the lead-out conductor pattern 22.

As shown in FIG. 2, the coil conductor pattern 24 is formed in a U shape or an arc shape so as to form the coil portion 12b. This coil conductor pattern 2
4 is a magnetic sheet 21 adjacent through a through hole.
The coil portion 12b of the internal electrode 12 is formed by connecting to the end of the coil conductor pattern 24.

As shown in FIG. 1, the external electrodes 14 are formed at both ends of the magnetic sintered body 11 in the laminating direction (the left-right direction in FIG. 1) so as to be connected to the lead portion 12a of the internal electrode 12. . Specifically, the external electrode 14 is formed from the end face to the side face of the magnetic sintered body 11, and is connected to the stress relaxing electrode 13 on the side face of the magnetic sintered body 11. The material of the external electrode 14 is made of a material mainly containing a metal such as Ag, for example. Further, a plating layer (not shown) is formed on a surface layer of the external electrode 14. This plating layer is formed by, for example, Ni plating or solder plating.

Next, a method of manufacturing the laminated inductor 10 will be described.

First, a magnetic sheet is prepared. Specifically, ethyl cellulose and terpineol are added to the calcined and ground ferrite fine powder composed of FeO ₂ , CuO, ZnO, and NiO, and the mixture is kneaded to obtain a ferrite paste. This ferrite paste is formed into a sheet using a doctor blade method or the like to obtain a magnetic sheet mainly containing ferrite.

Next, through holes are formed at predetermined positions in the magnetic sheet by a punch, a laser, or the like. Next, a conductive paste for an internal electrode is printed on the magnetic sheet in a predetermined pattern. This conductive paste is obtained by adding ethyl cellulose and butyl carbitol acetate to Ag and kneading them. The printing of the conductive paste is performed so as to become the lead-out conductor pattern 22, the stress relaxation conductor pattern 23, and the coil conductor pattern 24, as described above with reference to FIGS. Since the conductor pattern 23 for stress relaxation is formed on the same magnetic material sheet 21 as the conductor pattern 22 for extraction with the same composition and thickness, both can be printed in one step.

Next, a plurality of magnetic sheets are stacked in a predetermined order so that the sheets are connected to each other by through holes, and are pressed to obtain a stacked body. Next, this is cut into a unit shape and further subjected to barrel polishing.

Next, this unit-shaped laminate is heated in air at about 500 ° C. for 1 hour to remove the binder component in the laminate. Next, the laminate is further subjected to about 8 in air.
By baking at 00 to 900 ° C. for 2 hours, a magnetic sintered body in which the internal electrode and the electrode for stress relaxation are embedded is obtained.

Next, a conductive paste for an external electrode is applied to both ends of the magnetic sintered body by using a dipping method or the like, and the paste is baked at about 600 ° C. for 1 hour in the air. To form Next, electroplating is performed on the external electrodes to form a plating layer. Finally, the plating inductor is removed by rinsing with water and dried in a drying container to obtain the laminated inductor 10.

In such a laminated inductor 10, since the stress relaxing conductor pattern 23 having the same composition and thickness as the leading conductor pattern 22 is formed on the magnetic sheet 21 on which the leading conductor pattern 22 is formed. When the body sheets 21 are laminated and crimped, stress is not concentrated around the lead-out conductor pattern 22. Therefore,
Deformation of the laminate and displacement of the laminate due to concentration of stress are reduced. Further, since no stress remains in the laminate, the bending strength is also improved. Further, since the stress relaxing electrode 13 is exposed on the side surface of the magnetic sintered body 11 and is connected to the external electrode 14, the adhesive strength of the external electrode 14 is improved.

A large number of laminated inductors 10 according to the present embodiment are manufactured, and the average value, the maximum value, the minimum value, the standard deviation σ, and the variation coefficient Cv, which is an amount representing the variation, are obtained.
Was measured to obtain Table 1 below. In this measurement, as the laminated inductor 10 according to the present embodiment, 1.6 × 0.8 ×
One having a size of 0.8 mm ³ and an inductance value of 1.5 μH was prepared. As a comparison object, a conventional multilayer inductor 2 having the same shape and the same inductance value is used as a comparison object.
0 and 30 were also measured. Here, in the conventional laminated inductor 80, the direction in which the external electrodes are connected and the laminating direction are the same as in the laminated inductor 10. In the laminated inductor 90, the direction connecting the external electrodes and the laminating direction are orthogonal to each other.

[0033]

[Table 1]

As is apparent from the measurement, the laminated inductor 10 according to the present embodiment has a smaller standard deviation σ and a smaller coefficient of variation Cv than the conventional laminated inductor. That is, a high-precision multilayer inductor can be manufactured with a high manufacturing yield. In addition, the laminated inductor 10 is greatly improved in bending strength as compared with the conventional laminated inductor 80,
Further, the conventional laminated inductor 90 having a high bending strength in terms of structure.
It was found that the material had almost the same bending strength as the above.

In the present embodiment, as shown in FIG. 3, the conductor pattern 23 for stress relaxation is formed in an annular shape on the periphery of the magnetic sheet 21. However, the present invention is limited to such a shape. It is not something to be done. For example, as shown in FIG. 4, it may be formed in various shapes. In FIG. 4A, 4
Magnetic conductor sheet 23
Formed at the four corners. In FIG. 4B, four conductor patterns 23b for stress relaxation are formed at the center of each side of the magnetic sheet 21. In this way, a plurality of stress relaxation conductor patterns may be formed so as to be scattered on the magnetic sheet 21. In FIG. 4C, the annular stress relaxing conductor pattern 23c is formed so as not to be exposed at the edge of the magnetic sheet 21. In FIG. 4D, four stress relaxation conductor patterns 23 are formed at the four corners of the magnetic sheet 21 so as not to be exposed at the edges. Thus, the conductor pattern for stress relaxation may be formed so as not to be exposed at the edge of the magnetic sheet. In this case, since the connection between the stress relaxing electrode 13 formed by the stress relaxing conductor pattern and the external electrode 14 is lost, the bonding strength of the external electrode 14 cannot be improved.

In this embodiment, as shown in FIGS. 1 and 2, the stress relaxing conductor pattern 23 is replaced with all the magnetic sheets 21 on which the lead-out conductor pattern 22 is formed.
However, the present invention is not limited to this. For example, as shown in FIG. 5, it may be formed every several sheets.

Furthermore, in the present embodiment, the stress relaxing electrode 13 is formed to have the same composition as the internal electrode 12, but the present invention is not limited to this. That is, any member may be used as long as the member reduces the stress when the magnetic sheets are laminated, and may be either an insulator or a conductor. More specifically, a paste made of a substance similar to a sintered body (elementary body) such as a magnetic paste (ferrite material paste) and a dielectric paste (BaTiO ₃ ), Pd used for electrodes,
Ni paste or the like may be used. In particular, when the stress relaxation electrode 13 is formed using a conductive paste,
It is preferable to use a binder having the same binder as the conductive paste forming the lead-out conductor pattern 22.

Further, in the present embodiment, a multilayer inductor is illustrated as an example of a multilayer electronic component. However, the present invention is not limited to this, and the manufacturing method of the present invention can be applied to other multilayer electronic components. can do. For example, it may be a multilayer electronic component having a capacitor element such as a multilayer capacitor or a multilayer LC filter, or may be a multilayer electronic component having a plurality of inductor elements such as an inductor array. Furthermore, in the present embodiment, the laminated electronic component in which the lamination direction in which the problem of the bending strength is conspicuous is parallel to the circuit board on which it is mounted has been described.
The present invention is not limited to this.

[0039]

As described in detail above, according to the present invention,
When the insulating sheets are laminated and pressure-bonded, stress does not concentrate around the lead-out conductor patterns connected in the laminating direction via the through holes. That is, since the stress relaxation member is formed on the insulating sheet on which the lead conductor pattern is formed, the stress is absorbed by the stress relaxation member. Thereby, deformation of the outer shape of the laminated body due to concentration of stress and deformation of the laminated structure of the laminated body can be prevented. Further, since no stress remains in the laminate, the bending strength is also improved. Therefore, a multilayer electronic component can be manufactured with high precision and a high manufacturing yield.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a multilayer inductor.

FIG. 2 is an exploded perspective view of a multilayer body illustrating a multilayer structure of the multilayer inductor.

FIG. 3 is a plan view of a magnetic sheet illustrating a conductor pattern for stress relaxation.

FIG. 4 is a plan view of a magnetic sheet explaining a stress-relaxing conductor pattern according to another example.

FIG. 5 is a cross-sectional view of a multilayer inductor according to another example.

FIG. 6 is a sectional view of a conventional multilayer inductor.

FIG. 7 is an exploded perspective view illustrating a laminated structure of a conventional laminated inductor.

FIG. 8 is a diagram illustrating a magnetic sintered body in a conventional multilayer inductor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... laminated inductor, 11 ... magnetic sintered compact, 12 ... internal electrode, 12a ... lead-out part, 12b ... coil part, 13 ... stress relaxation electrode, 14 ... external electrode, 21 ... magnetic material sheet, 2
2 ... Pull-out conductor pattern, 23 ... Stress relaxation conductor pattern, 24 ... Coil conductor pattern

Claims (6)

[Claims] 1. A laminate formed by laminating a plurality of insulating sheets on which a conductor pattern is printed so that the conductor patterns are connected to each other through through holes, and formed at both ends of the laminate in the laminating direction. In the multilayer electronic component including an external electrode, the conductor pattern is connected to an element conductor pattern for forming an electric element in a stacking direction via a through hole to connect the electric element and the external electrode. A laminated electronic component, comprising: a lead-out conductor pattern; and an insulating sheet on which the lead-out conductor pattern is formed, wherein a stress relaxation member that relieves stress in the laminate is formed. 2. The multilayer electronic component according to claim 1, wherein the stress relaxation member is formed on a peripheral portion of an insulating sheet. 3. The multilayer electronic component according to claim 1, wherein the stress relaxation member is formed to have the same thickness as the lead-out conductor pattern. 4. The stress relaxation member according to claim 1, wherein the stress relaxation member is formed of a conductor, is exposed on a side surface of the laminate, and is connected to an external electrode formed around the side surface. 4. The multilayer electronic component according to claim 3. 5. The multilayer electronic component according to claim 1, wherein the stress relaxation member is formed of the same material as the lead-out conductor pattern. 6. The multilayer electronic component according to claim 1, wherein the electric element includes an inductor element.