JP2003100516A - Laminated inductor and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated inductor which has a structure capable of retaining the magnetic properties of its main body, avoiding the influence of the residual stress of an internal conductor on a magnetic body, and preventing an L value and a Q value from deceasing or varying due to a deterioration in magnetic property. SOLUTION: In a case of this laminated inductor 1', internal conductor layers are formed of a material whose thermal shrinkage factor is 10% or above within a temperature range from 300 to 400 deg.C and formed integrally by baking, by which a gap 13 of thickness 0.1 to 5 μm is formed around a conductor pattern (as shown in the enlarged view of a region E, a thermal load is given in baking, so that an internal conductor 12' is thermally shrunk to form the gap 13 between a magnetic body 14 and the internal conductor 12'). Therefore, the influence of the residual stress of the internal conductor 12' on the magnetic body 14 can be avoided, and the magnetic body 14 is capable of keeping its intrinsic magnetic properties unchanged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated inductor, which is an inductance element which is mainly mounted on a printed wiring board or the like as a noise countermeasure component for a DC power supply line or a choke coil, and which is used under one-sided excitation. The manufacturing method is related.

[0002]

2. Description of the Related Art Conventionally, as a laminated inductor of this type, for example, one having a structure as shown in FIGS. However, FIG. 7 is shown to explain the basic structure of a conventional multilayer inductor, FIG. 7A is an exploded perspective view, FIG. 7B is an external perspective view, and FIG. c) relates to a schematic perspective view showing the internal conductor pattern by perspective extraction.

Referring to FIGS. 7 (a) to 7 (c), this laminated inductor 10 has a magnetic powder of spinel type soft magnetic ferrite containing Ni, Zn, Cu and Fe as main components and A.
and a conductive powder such as Ag-Pd are mixed with a binder and a solvent and kneaded to form a magnetic material paste and an internal conductor paste, which are alternately printed with a screen plate. It is produced by producing a printed laminate having a body layer and an internal conductor layer.

Specifically, as shown in FIG. 7A, first, in the step of forming a magnetic layer, a green sheet which is a first magnetic layer made of a magnetic material obtained by processing a magnetic material such as ferrite. 5 are formed in advance, and then, in the step of forming a laminated body, internal conductor layers having predetermined different conductor patterns 61 to 65 to be internal conductors between the green sheets 5 and through windows 711, 721, 731 at predetermined different positions. The magnetic material sheets 71 to 74, which are the second magnetic material layers made of a magnetic material, are alternately laminated so as to dispose 741 and are sintered to pass through the through windows 711, 721, 731, and 741 and the conductor patterns 61. ~ 65 (that is, the conductor pattern 6)
1, 62, conductor patterns 62, 63, conductor pattern 6
3, 64 and a combination of the conductor patterns 64 and 65 are conducted, and a part of the conductor pattern (here, one side of the conductor patterns 61 and 65 facing each other) is extended to the outer surface perpendicular to the stacking direction. The stack is formed so that the exposed portions (showing portions) are exposed.

In this case, after the inner conductor layer of the conductor pattern 61, which is a local portion of the coil-shaped inner conductor (inner electrode) 4, is formed by printing on the upper surface of the green sheet 5 on the lower surface side, the upper surface thereof is formed. The second magnetic layer is formed by printing the magnetic sheet 71 so that the through window 711 is formed. Similarly, after the inner conductor layer of the conductor pattern 62, which is another local portion of the coil-shaped inner conductor 4, is formed by printing on the upper surface of the magnetic material sheet 71, a through window 721 is formed on the upper surface. As described above, the second magnetic layer formed of the magnetic sheet 72 is formed by printing. Further, similarly, an inner conductor layer of the conductor pattern 63 which is another local portion of the coil-shaped inner conductor 4 is formed by printing on the upper surface of the magnetic material sheet 72, and then a through window 731 is formed on the upper surface. As described above, the second magnetic layer formed of the magnetic sheet 73 is formed by printing. Subsequently, an inner conductor layer of the conductor pattern 64, which is still another local portion of the coiled inner conductor 4, is formed by printing on the upper surface of the magnetic sheet 73 by screen printing, and then a through window 741 is formed on the upper surface. Magnetic sheet 74
To form a second magnetic layer by printing. Further, an inner conductor layer of the conductor pattern 65, which is another local portion of the coil-shaped inner conductor 4, is formed by printing on the upper surface of the magnetic material sheet 74, and then the green sheet 5 on the upper surface side with respect to the upper surface. Superimpose.

That is, in the step of forming the laminated body, the steps of forming the internal conductor layers and the second magnetic layer are alternately repeated a plurality of times, so that each conductor layer and each magnetic layer directly contact each other. In such a state that the coil-shaped inner conductor 4 having a desired number of turns is formed inside the magnetic material, the printed laminated body is manufactured by press-bonding the laminated body to a predetermined laminated thickness and applying a constant pressure.

Further, after the produced printed laminated body is cut into a single body of a predetermined size, the binder is removed, and then integrally fired at a temperature at which sintering is possible in the firing step, Each of the conductor patterns 61 to 65 has a through window 71.
7, 721, 731, and 741 are conductively connected to each other to form the coil-shaped inner conductor 4 as shown in FIG. 7C, and the exposed portions of the conductor patterns 61 and 65 exposed on the outer surfaces are respectively coil-shaped inner conductors. 4 is the start end and the end end of the conductor pattern 4, and the conductor patterns 61 exposed on the outer surface of the laminated body as shown in FIG.
The laminated inductor 10 is manufactured by connecting and arranging the external electrodes 2 to the exposed portions of 65, respectively. still,
When changing the number of turns in the coiled inner conductor 4 of the laminated inductor having such a configuration, the shape of the conductor pattern may be changed, or the number of laminated layers of the inner conductor layer and the second magnetic layer may be increased or decreased.

[0008]

In the case of the above-mentioned laminated inductor, the structure is such that the magnetic body is in close contact with the internal conductor, and the laminated body is integrally fired at a predetermined temperature at which it can be sintered in the firing step. However, it is known that residual stress occurs due to the difference in thermal expansion coefficient between the second magnetic layer and the internal conductor layer in the printed laminate during the cooling process after firing. When stress acts on the magnetic substance from the inner conductor, the magnetic properties of the magnetic substance are deteriorated, which causes the L value (inductance value) and the Q value (quality factor value) to be reduced, or the values are varied. It is causing the problem of letting it go.

The present invention has been made to solve such a problem, and its technical problem is that the effect of residual stress from the internal conductor to the magnetic body can be avoided and the original magnetic characteristics can be maintained. It is an object of the present invention to provide a laminated inductor and a manufacturing method thereof, which has a structure and which can prevent a decrease in the L value and the Q value due to deterioration of the magnetic characteristics and suppress variation in those values.

[0010]

According to the present invention, an inner conductor layer having a predetermined conductor pattern to be an inner conductor and a through window are provided at a predetermined position between first magnetic layers made of a magnetic material. Second magnetic material layers made of magnetic material are alternately laminated, and the conductor patterns can be electrically connected to each other through the through window by sintering, and the conductor patterns are formed on the outer surface perpendicular to the laminating direction. In a laminated inductor formed by connecting and arranging an external electrode to a part of the conductor pattern exposed on the outer surface of a laminated body integrally fired so as to expose a part of the conductor pattern, A laminated inductor in which gaps are discontinuously formed in the predetermined range with a thickness within a predetermined range can be obtained. In this laminated inductor, it is preferable that the predetermined range is 0.1 to 5 μm, and that the gap is formed in either the second magnetic layer or the internal conductor layer.

On the other hand, according to the present invention, a magnetic layer forming step for forming a first magnetic layer made of a magnetic material and an internal conductor having a predetermined conductor pattern to be an internal conductor between the first magnetic layers. Layers and second magnetic material layers made of a magnetic material are alternately laminated so as to arrange the through windows at predetermined positions, and the conductor patterns are electrically connected to each other through the through windows by sintering, and the lamination direction is A laminated body forming step of forming a laminated body so that a part of the conductor pattern is exposed on a vertical outer surface; a firing step of integrally firing the laminated body at a temperature at which the laminated body can be sintered; and an outer peripheral surface of the laminated body. And a step of forming an external electrode by connecting an external electrode to a portion of the conductor pattern exposed at the step of forming a laminated inductor, wherein in the laminated body forming step, the material of the internal conductor layer is formed. 300 ~ 400 ℃ A laminated inductor in which a material having a heat shrinkage ratio of 10% or more in a temperature range is used, and in the firing step, a gap is discontinuously formed around the conductor pattern in a thickness of 0.1 μm to 5 μm by integral firing. Can be obtained.

Further, according to the present invention, in the above-mentioned method for manufacturing a laminated inductor, the material of the internal conductor layer used in the step of forming a laminated body has a second difference in thermal shrinkage in the temperature range of 800 to 900 ° C. It is possible to obtain a method for manufacturing a laminated inductor in which the ratio between the magnetic layer and the magnetic layer is 20% or more.

On the other hand, according to the present invention, a magnetic layer forming step for forming a first magnetic layer made of a magnetic material and an internal conductor having a predetermined conductor pattern to be an internal conductor between the first magnetic layers. Layers and second magnetic material layers made of a magnetic material are alternately laminated so as to arrange the through windows at predetermined positions, and the conductor patterns are electrically connected to each other through the through windows by sintering, and the lamination direction is A laminate forming step of forming a laminate so that a part of the conductor pattern is exposed on a vertical outer surface; a firing step of integrally firing the laminate at a temperature at which it can be sintered; and an outer surface of the laminate. And a step of forming an external electrode by connecting and deploying an external electrode to a part of the conductor pattern exposed at the step of forming a laminated inductor. The inner conductor layer in advance as a layer By using the one that is formed by thinly forming a concave shape in a discontinuous manner so that the vicinity of the portion contacting the conductor pattern is not in contact with the conductor pattern, a range of 0.1 μm to 5 μm is provided around the conductor pattern in the laminate. A method of manufacturing a laminated inductor in which a gap is formed discontinuously in thickness is obtained.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The multilayer inductor and the method for manufacturing the same according to the present invention will be described below in detail with reference to the drawings.

First, the technical outline of the laminated inductor and the manufacturing method thereof according to the present invention will be briefly described. The multilayer inductor according to the present invention is configured such that, between the first magnetic material layer made of a magnetic material, the internal conductor layer having a predetermined conductor pattern as an internal conductor and the magnetic material having a through window provided at a predetermined position are provided. Magnetic layers are alternately laminated and
The conductor exposed on the outer surface of the laminated body which is integrally fired so that the conductor patterns can be electrically connected to each other through the through window by sintering and a part of the conductor pattern is exposed on the outer surface perpendicular to the stacking direction. 7 (a) to 7 (c) configured by connecting and deploying external electrodes to a part of the pattern.
The common point is that they have the same basic structure as described above, but as a basic structure, a predetermined 0.
The difference lies in the structure in which gaps are formed discontinuously with a thickness in the range of 1 to 5 μm. However, the gap here may be formed in either the second magnetic layer or the internal conductor layer.

In manufacturing such a laminated inductor, basically, as described with reference to FIGS. 7A to 7C, a magnetic layer forming step, a laminated body forming step, a laminated body forming step, and an external step. It is assumed that the electrode forming step is carried out, and the material of the internal conductor layer having a heat shrinkage ratio of 10% or more in the temperature range of 300 to 400 ° C. is used in the laminate forming step.
In the firing step, integral firing is performed to reduce the area around the conductor pattern to 0.
A gap may be formed discontinuously in a thickness range of 1 μm to 5 μm, or a portion near a portion of the inner conductor layer that is previously abutted with the conductor pattern as the second magnetic layer in the layered body forming step may be formed. By using a material that is formed by thinning a concave shape in a discontinuous manner so as not to contact with each other, it is possible to discontinuously form a gap with a thickness in the range of 0.1 μm to 5 μm around the conductor pattern in the laminated body. You can do it. However, in the case of the former manufacturing method, when the material of the internal conductor layer used in the step of forming the laminated body has a difference in the heat shrinkage ratio within the temperature range of 800 to 900 ° C.
It is preferable to be 20% or more with respect to the magnetic layer.

According to the former manufacturing method, the shrinkage rate of the internal conductor paste used for forming the conductor pattern of the internal conductor layer is set to shrink by 10% or more in the temperature range of 300 to 400 ° C., whereby a printed laminate is obtained. 3 at the time of sintering
A gap is formed between the inner conductor layer and the magnetic layer in the relatively low temperature range of 00 to 400 ° C., and the magnetic paste and the inner conductor are used in the sintering temperature range of 850 to 930 ° C. Since the difference in shrinkage between the paste and the heat shrinkage is 20% or more, the gap formed between the two becomes sufficiently large.

Even when the latter manufacturing method is followed, since there is a gap as a gap between the internal conductor layer and the magnetic material layer, residual stress from the internal conductor layer to the magnetic material layer is generated during the cooling process after sintering. Since the influence is avoided, residual stress is not generated inside the magnetic layer, and the magnetic characteristic originally possessed by the magnetic layer can be maintained. Therefore, the L value and Q due to the deterioration of the magnetic characteristic can be maintained.
It is possible to prevent a decrease in the values and suppress variations in those values.

The laminated inductor of the present invention will be described below in detail with reference to some examples and comparative examples together with the manufacturing method thereof.

(Embodiment 1) In the laminated inductor according to Embodiment 1 of the present invention, external electrodes are arranged at both ends of a laminated body in which a coiled internal conductor (internal electrode) is embedded in a magnetic body in the basic structure. It is the same as before, but
Here, the material of the inner conductor layer is 300 to
A material according to one embodiment having a thermal shrinkage of 10% or more in the temperature range of 400 ° C. is used.

Specifically, Ni--Zn--Cu ferrite powder is prepared as the magnetic powder for forming the magnetic layer, and the ferrite powder is mixed with a binder and a solvent to obtain three compounds. The mixture was kneaded with a roll to prepare a magnetic paste. Further, as a powder used for forming the conductor pattern of the internal conductor layer, a mixture obtained by mixing Ag powder with a binder and a solvent was kneaded with a three-roll to prepare an internal conductor paste.

FIG. 1 shows the shrinkage percentage (%) of the magnetic material (paste for magnetic material) and the internal conductor material (paste for internal conductor) used for manufacturing the laminated inductor according to the first embodiment, with respect to temperature ° C. It shows the heat shrinkage rate characteristics of the measurement results. However, in this heat shrinkage rate characteristic, the one for the magnetic paste is the heat shrinkage curve C _{M1, and the} one for the internal conductor paste is the heat shrinkage curve C _P 1.

In FIG. 1, in the case of the thermal contraction rate curve C _M 1 of the magnetic paste, the contraction rate is almost 0% even if it exceeds 800 ° C.
On the other hand, in the case of the thermal contraction rate curve C _P 1 of the internal conductor paste, the contraction starts around 300 ° C.
It shows the state of shrinking by 10% or more by 00 ° C.

That is, in Example 1, the basic self-process for manufacturing the laminated inductor is the same as the conventional process. Therefore, referring to FIG. 7A, the heat-shrinkage curve C is added to the magnetic paste. _A green sheet 5 is produced using a material having a characteristic as shown by _M 1, and screen printing is performed on the upper surface of the green sheet 5 by using a material having a characteristic as shown by a heat shrinkage rate curve C _P 1 for an internal conductor paste. After the inner conductor layer of the conductor pattern 61 which is a local portion of the coiled inner conductor (inner electrode) 4 is formed by printing by the method, the material having the characteristic as shown by the heat shrinkage ratio curve C _M 1 on the upper surface thereof is also formed. The second magnetic material layer of the magnetic material sheet 71 is formed by printing so that the through window 711 is formed by using. At this stage, since the through window 711 is provided in advance, after the magnetic pattern of the magnetic material sheet 71 is printed, the end portion of the conductor pattern 61 is located at the through window 71.
It is exposed to the upper surface side through 1 and secures a joint portion with a conductor pattern 62 formed later.

Similarly, a conductor pattern to be another local portion of the coil-shaped inner conductor 4 is formed on the upper surface of the magnetic sheet 71 by screen printing using a material having a characteristic as shown by the heat shrinkage rate curve C _P 1. After the inner conductor layer 62 is formed by printing, a second magnetic sheet 72 is formed so that a through window 721 is formed on the upper surface of the inner conductor layer by using a material having a characteristic as indicated by the heat shrinkage rate curve C _M 1. The magnetic layer is formed by printing. Further, similarly, the inside of the conductor pattern 63, which is another local portion of the coil-shaped inner conductor 4, is formed by the screen printing method using a material having the characteristics shown by the heat shrinkage rate curve C _P 1 on the upper surface of the magnetic material sheet 72. After the conductor layer is formed by printing, the second magnetic material formed by the magnetic material sheet 73 is formed on the upper surface of the conductor layer so that the through window 731 is formed by using the material having the characteristic shown by the heat shrinkage rate curve C _M 1. Print the layers. Subsequently, the heat shrinkage rate curve C is applied to the upper surface of the magnetic sheet 73.
_After the inner conductor layer of the conductor pattern 64, which is the other local portion of the coiled inner conductor 4, is formed by screen printing by using the material having the characteristics shown in _P 1, the heat shrinkage rate is applied to the upper surface of the inner conductor layer. The second magnetic material layer of the magnetic material sheet 74 is formed by printing so that the through window 741 is formed by using the material having the characteristics shown by the curve C _M 1. Furthermore,
An inner conductor layer of the conductor pattern 65, which is another local portion of the coiled inner conductor 4, is formed on the upper surface of the magnetic sheet 74 by a screen printing method using a material having a characteristic as shown by the heat shrinkage rate curve C _P 1. After printing and forming, a green sheet 5 on the upper surface side is superposed on the upper surface by using a material having a characteristic as shown by the heat shrinkage rate curve C _M 1.

That is, here again, by alternately repeating the step of forming the inner conductor layer and the second magnetic layer in the step of forming the laminated body a plurality of times, each conductor layer does not directly contact with each magnetic layer. In this state, the coil-shaped inner conductor 4 having 3.5 turns is formed inside the magnetic material, and the laminated thickness is set to 1.3 mm, and then pressure-bonded with a constant pressure to produce a printed laminated body. In addition, here
Although the number of turns in the coiled inner conductor 4 is 3.5, other numbers of turns may be used, and the number of turns is adjusted so as to obtain a required inductance.

Further, after the produced printed laminate is cut into a predetermined size (2.4 mm × 2.0 mm × 1.3 mm) and binder is removed, it is simultaneously subjected to a temperature condition of 900 ° C. Firing was performed. In addition, here, it is assumed that the firing is performed at 900 ° C., but generally, the firing temperature is about 850.
It may be carried out in the range of ˜930 ° C. Further, here, the size of one laminated body element is 2.4 mm × 2.0 mm × 1.3.
Although the size is set to mm, other sizes may be used, and in that case, the size of the coil-shaped inner conductor 4 may be adjusted.

Finally, Ag is a main component so that the lead of the coil-shaped inner conductor 4 formed by the inner conductor layers of the conductor patterns 61 and 65 is exposed on the outer surface of the fired laminate. After forming the external electrode 2 by applying the conductive paste described above and baking at about 600 ° C., the external electrode 2 was plated with Ni and Sn to complete the laminated inductor. Although a conductive paste containing Ag as a main component is used as a material for forming the external electrode 2 here, a conductive paste containing carbon, Cu, Ni, or the like as a main component is also used. May be.

(Embodiment 2) Also in the case of the laminated inductor according to Embodiment 2 of the present invention, the external electrodes are provided at both ends of the laminated body in which the coil-shaped internal conductor (internal electrode) is embedded in the magnetic body in the basic structure. Is the same as before, but here the material for the inner conductor layer is 3
A material according to another embodiment having a heat shrinkage of 10% or more in the temperature range of 00 to 400 ° C., and a difference of the heat shrinkage of 20% or more with the magnetic layer in the temperature range of 800 to 900 ° C. To use.

Specifically, three Ni-Zn-Cu ferrite powders are prepared as magnetic powders for forming the magnetic layer, and the ferrite powders are mixed with a binder and a solvent to obtain three compounds. The mixture was kneaded with a roll to prepare a magnetic paste. Further, as a powder used for forming the conductor pattern of the internal conductor layer, a mixture obtained by mixing Ag powder with a binder and a solvent was kneaded with a three-roll to prepare an internal conductor paste.

FIG. 2 shows the shrinkage percentage (%) of the magnetic material (paste for magnetic material) and the internal conductor material (paste for internal conductor) used for manufacturing the laminated inductor according to the second embodiment, with respect to the temperature ° C. It shows the heat shrinkage rate characteristics of the measurement results. However, in this heat shrinkage rate characteristic, the heat shrinkage rate curve C _M 2 is for the magnetic paste, and the heat shrinkage rate curve C _P 2 is for the internal conductor paste.

[0032] In Figure 2, if the heat shrinkage curve C _M 2 of the magnetic paste, heat shrinkage according to Example 1 above curve C _M
Similar to the case of 1, the shrinkage rate is almost 0% even if it exceeds 800 ° C.
On the other hand, in the case of the thermal contraction rate curve C _P 2 of the internal conductor paste, the contraction starts around 300 ° C. and 4
In addition to shrinking by 10% or more by 00 ° C., the shrinkage ratio at 900 ° C. shows a difference of 20% or more in comparison with the heat shrinkage ratio curve C _M 2.

That is, in Example 2, the heat shrinkage rate curve C _M 2 was used for the magnetic paste and the heat shrinkage rate curve C _P 2 was used for the internal conductor paste. By following the exact same manufacturing procedure as in the above case, a laminated inductor having a similar appearance was completed.

(Comparative Example) Also in the case of the laminated inductor according to the comparative example, in the basic structure, the external electrodes are provided at both ends of the laminated body in which the coiled internal conductor (internal electrode) is embedded in the magnetic body. However, in this case, the material of the inner conductor layer is 300 to 400 at the step of forming the laminated body.
In the temperature range of ℃, the heat shrinkage is about 6%.
A material according to another form is used, which has a heat shrinkage ratio at 0 ° C. of about 10% with respect to the magnetic layer.

More specifically, here, a Ni-Zn-Cu ferrite powder is prepared as the magnetic powder for forming the magnetic layer, and the ferrite powder is mixed with a binder and a solvent to obtain a mixture. A three-roll mill was kneaded to produce a magnetic paste. Further, as a powder used for forming the conductor pattern of the internal conductor layer, a mixture obtained by mixing Ag powder with a binder and a solvent was kneaded with a three-roll to prepare an internal conductor paste.

FIG. 3 shows the temperature in degrees Celsius of the magnetic material (paste for magnetic material) and the internal conductor material (paste for internal conductor) used in the manufacture of the laminated inductor according to the comparative example.
3 shows the heat shrinkage rate characteristics of the result of measuring the shrinkage rate% with respect to. However, in this heat shrinkage rate characteristic, the heat shrinkage rate curve C _M 3 for the magnetic paste and the heat shrinkage rate curve C _P 3 for the internal conductor paste.

[0037] In Figure 3, when the heat shrinkage curve C _M 3 of the magnetic paste, heat shrinkage according to Example 2 above curve C _M
2 shows the same shrinkage rate characteristics as in the case of No. 2, but in the case of the heat shrinkage rate curve C _P 3 of the internal conductor paste, shrinkage starts at around 300 ° C. and shrinks only about 6% by 400 ° C. Furthermore, it shows that the shrinkage at 900 ° C. is in a state where there is a difference of about 10% in comparison with the heat shrinkage curve C _M 3.

That is, in the comparative example, the heat shrinkage rate curve C _M 3 is used for the magnetic paste and the heat shrinkage rate curve C _P 3 is used for the internal conductor paste.
By following the same manufacturing procedure as in the case of 1., a laminated inductor having substantially the same appearance was completed.

Therefore, when the details of the manufacturing state of the laminated body after sintering of each laminated inductor manufactured as described above are structurally observed, the results shown in FIGS. 4 to 6 are obtained. Was given. That is, here, FIG. 4 is a sintering process for schematically explaining the detailed structure of the multilayer inductor 1'according to the first embodiment, which is manufactured using the material having the heat shrinkage ratio characteristic shown in FIG. It is sectional drawing in the surface parallel to the end surface in the longitudinal direction of a subsequent laminated body, and its partially expanded view. or,
FIG. 5 is a laminated body after sintering, which is shown to schematically explain the detailed structure of the laminated inductor 1 ″ according to the second embodiment, which is manufactured using the material having the heat shrinkage ratio characteristic shown in FIG. 6 is a cross-sectional view and a partially enlarged view of a plane parallel to an end face in the longitudinal direction of Fig. 6. Further, Fig. 6 is a laminated inductor according to a comparative example, which is manufactured using the material having the heat shrinkage rate characteristic shown in Fig. 3. FIG. 2 is a cross-sectional view and a partially enlarged view of a laminated body after sintering shown for schematically explaining the detailed structure of No. 1 in a plane parallel to an end face in the longitudinal direction.

Comparing the figures, in the case of the laminated inductor 1 shown in FIG. 6, the internal structure of the laminated body after sintering is sintered, as is apparent from the enlarged view of the region E. Even if a heat load is applied during the integrated firing for
2 has a structure in which the magnetic body 14 is almost in close contact with the inner conductor 12 because the material 2 does not shrink so much as shown in FIG.
In the case of the laminated inductor 1'shown in Fig. 6, as is apparent from the enlarged view of the region E, the inner conductor 12 'is thermally contracted by the heat load applied during the integrated firing, so that the magnetic body 14 and the inner conductor 12' are contracted. In the case of the laminated inductor 1 ″ shown in FIG. 5, a gap 13 is formed between the inner conductors, and as is apparent from the enlarged view of the region E, a heat load is similarly applied during the integrated firing, so that the inner conductor is It can be seen that 12 ″ is thermally contracted to form a gap 13 ′ between the magnetic body 14 and the inner conductor 12 ″.

Further, with respect to each of the laminated inductors manufactured as described above, the L value and the Q value and their variations were evaluated using an impedance analyzer HP4191A manufactured by YHP, and thereafter, the temperature was 40 ° C. for 9 hours.
~ 1000% of each laminated inductor in a humidity resistant tank of 95% RH
When the rate of change of L value and Q value in the moisture resistance test was measured again while maintaining the time, the results shown in Table 1 were obtained.

[0042]

[Table 1]

From Table 1, it can be seen that the laminated inductors 1'and 1 "of Examples 1 and 2 have L and Q values of 20% or more in relative ratio to the laminated inductor 1 of the comparative example. As compared with the case of the comparative example, the variations of the L value and the Q value are all reduced to about half or less, and the rate of change of the L value and the Q value after the moisture resistance test is also smaller than that of the case of the comparative example. It can be seen that the change has been much less.

Therefore, the laminated inductors 1 ', 1 "according to the first and second embodiments in which the gaps 13, 13' are formed.
Has a structure in which the effect of residual stress from the inner conductors 12 ', 12 "on the magnetic body 14 is avoided in the cooling process after sintering and the original magnetic characteristics are maintained. It is possible to prevent the decrease of the value and to have the high moisture resistance capable of suppressing the variation of the values.

In the laminated inductors 1'and 1 "according to the first and second embodiments described above, the material of the internal conductor layer has a heat shrinkage rate of 10 in the temperature range of 300 to 400 ° C. in the laminated body forming step. %, The conductor pattern (internal conductors 12 ', 1
2 ″), the gaps 13 and 13 ′ are formed discontinuously with a thickness in the range of 0.1 μm to 5 μm. However, as described in the technical outline at the beginning, the second gap is formed in the second step. The magnetic material layer is formed as a discontinuous concave thinning so that the vicinity of a portion abutted with the conductor pattern of the inner conductor layer (in this case, the inner conductor that does not contract heat) becomes non-contact. 1 to 5 μm with a thickness in the range of 0.1 μm to 5 μm around the conductor pattern in the laminated body.
Even if 3,3 'are formed discontinuously, the same effect can be obtained.

[0046]

As described above, according to the present invention, by forming a gap between the magnetic layer and the internal conductor layer in the laminated body of the laminated inductor, the internal conductor is cooled during the sintering process. The structure is such that the influence of residual stress on the magnetic material is avoided and the original magnetic characteristics are maintained, and as a result, the L value and Q value are prevented from lowering due to the deterioration of the magnetic characteristics, and at the same time, those values are prevented. It becomes possible to manufacture a laminated inductor having high moisture resistance capable of suppressing the variation of

[Brief description of drawings]

FIG. 1 is a graph showing the heat shrinkage rate characteristics as a result of measuring the shrinkage rates with respect to temperature of a magnetic material and an internal conductor material used for manufacturing a laminated inductor according to Example 1 of the present invention.

FIG. 2 shows heat shrinkage ratio characteristics as a result of measuring shrinkage ratios with respect to temperature of a magnetic material and an internal conductor material used for manufacturing a laminated inductor according to Example 2 of the present invention.

FIG. 3 is a graph showing heat shrinkage ratio characteristics as a result of measuring shrinkage ratios with respect to temperature of a magnetic material and an internal conductor material used for manufacturing a laminated inductor according to a comparative example.

FIG. 4 is a length of a laminated body after sintering shown for schematically explaining a detailed structure of a laminated inductor according to an example 1 manufactured by using a material having a heat shrinkage ratio characteristic shown in FIG. FIG. 3 is a cross-sectional view taken along a plane parallel to the end face in the direction and a partially enlarged view thereof.

5 is a longitudinal view of a laminated body after sintering shown for schematically explaining a detailed structure of a laminated inductor according to an example 2 manufactured by using a material having a heat shrinkage ratio characteristic shown in FIG. FIG. 3 is a cross-sectional view taken along a plane parallel to the end face in the direction and a partially enlarged view thereof.

FIG. 6 is a longitudinal direction of a laminated body after sintering shown for schematically explaining a detailed structure of a laminated inductor according to a comparative example manufactured by using the material having the heat shrinkage ratio characteristic shown in FIG. FIG. 3 is a cross-sectional view taken along a plane parallel to the end face in FIG.

7A and 7B are shown for explaining the basic structure of a conventional multilayer inductor, FIG. 7A is an exploded perspective view, FIG. 7B is an external perspective view, and FIG. 7C is an internal conductor pattern. FIG. 3 is a perspective view showing a perspective view of FIG.

[Explanation of symbols]

1,1 ', 1 ", 10 Multilayer inductor 2 external electrodes 3 Magnetic part 4 Coil-shaped internal conductor (internal electrode) 5 green sheets 12,12 ', 12 "inner conductor 13,13 'gap 14 Magnetic material 61-65 conductor pattern 71-74 Magnetic sheet 711, 721, 731, 741 Through window

Claims (6)

[Claims] 1. An internal conductor layer having a predetermined conductor pattern to be an internal conductor between a first magnetic body layer made of a magnetic body and a second magnetic body having a through window provided at a predetermined position.
Magnetic layers are alternately laminated, and the conductor patterns can be electrically connected to each other through the through window by sintering, and a part of the conductor pattern is exposed on the outer surface perpendicular to the laminating direction. In a laminated inductor constituted by connecting and arranging an external electrode to a part of the conductor pattern exposed on the outer surface of the laminated body integrally fired in a laminated body, a predetermined pattern is provided around the conductor pattern. A laminated inductor, wherein a gap is formed discontinuously with a thickness in the range. 2. The multilayer inductor according to claim 1, wherein the predetermined range is 0.1 to 5 μm. 3. The multilayer inductor according to claim 1, wherein the gap is formed in either the second magnetic layer or the internal conductor layer. 4. A magnetic body layer forming step of forming a first magnetic body layer made of a magnetic body, an internal conductor layer having a predetermined conductor pattern to be an internal conductor between the first magnetic body layers, and a predetermined position. A second member made of a magnetic material so that a through window is provided in the second
The magnetic layers are alternately laminated, and the laminated body is formed by sintering so that the conductor patterns are electrically connected to each other through the through window and a part of the conductor pattern is exposed on an outer surface perpendicular to the laminating direction. A step of forming a laminated body to be formed, a step of integrally firing the laminated body at a temperature at which the laminated body can be sintered, and an external electrode for a part of the conductor pattern exposed on the outer surface of the laminated body. In the method of manufacturing a laminated inductor, the method comprising: connecting and deploying to form an external electrode to obtain a laminated inductor, wherein in the laminated body forming step, the material of the internal conductor layer has a heat shrinkage ratio in a temperature range of 300 to 400 ° C. 10% or more is used, and in the firing step, 0.1 μm is formed around the conductor pattern by the integrated firing.
A method for manufacturing a laminated inductor, characterized in that gaps are formed discontinuously with a thickness in the range of ˜5 μm. 5. The method of manufacturing a laminated inductor according to claim 4, wherein the material of the internal conductor layer used in the step of forming the laminated body has a difference in thermal contraction rate in a temperature range of 800 to 900 ° C. 20% or more between the magnetic layer and the magnetic layer. 6. A magnetic material layer forming step of forming a first magnetic material layer made of a magnetic material, an internal conductor layer having a predetermined conductor pattern to be an internal conductor between the first magnetic material layers, and a predetermined position. A second member made of a magnetic material so that a through window is provided in the second
The magnetic layers are alternately laminated, and the laminated body is formed by sintering so that the conductor patterns are electrically connected to each other through the through window and a part of the conductor pattern is exposed on an outer surface perpendicular to the laminating direction. A step of forming a laminated body to be formed, a step of integrally firing the laminated body at a temperature at which the laminated body can be sintered, and an external electrode for a part of the conductor pattern exposed on the outer surface of the laminated body. In the method of manufacturing a laminated inductor, the external electrode forming step of connecting and deploying to obtain a laminated inductor, wherein the forming of the laminated body corresponds to the conductor pattern of the internal conductor layer in advance as the second magnetic layer. 0.1 μm to the periphery of the conductor pattern in the laminate is used by using a material that is formed by thinly forming a concave shape in a discontinuous manner so that the vicinity of the contacted portion becomes non-contact.
A method of manufacturing a laminated inductor, characterized in that a gap is formed discontinuously with a thickness in a range of 5 μm.