JP4973996B2 - Laminated electronic components - Google Patents

Description

  The present invention relates to a multilayer electronic component such as a DC-DC converter that combines a multilayer inductor, a substrate incorporating the multilayer inductor, a DC-DC converter control circuit, and an active element such as a semiconductor integrated circuit including a switching element.

Many portable electronic devices (such as mobile phones, personal digital assistants PDAs, notebook computers, DVDs, CDs, MD players, digital cameras, video cameras, etc.) use batteries as the power source, and operate the power supply voltage at a predetermined level. A DC-DC converter is provided as a power conversion device that converts voltage.
In a DC-DC converter, a semiconductor integrated circuit (active element) including a switching element and a control circuit and passive elements such as an inductor and a capacitor are generally configured as a discrete circuit on a printed circuit board or the like on which a connection line is formed. However, with the downsizing of electronic devices, it is required to reduce the volume occupied by the DC-DC converter itself by downsizing the passive element or combining the passive element and the active element. .

  Up to now, many inductors of the winding type in which a conducting wire is wound around a magnetic core have been used. However, there is a limit to miniaturization, and multilayer inductors have been used. It has also been proposed to use a multilayer inductor as a multilayer substrate and mount a semiconductor integrated circuit on the multilayer substrate to form a composite.

Although there are various structures of multilayer electronic components such as multilayer inductors and multilayer substrates, a general structure is shown in a sectional view of FIG. In the multilayer electronic component, the magnetic body (ferrite) 80 and the internal conductor (conductor pattern) 60 are integrally formed by a sheet lamination method, a printing method, or the like, and then fired at the same time, and external terminal paste is applied to the surface of the obtained fired body. It has a so-called monolithic structure that is printed or transferred and baked to form external terminals (not shown).
Such a multilayer electronic component is excellent in mechanical strength and has a structure suitable for downsizing, but has several problems due to the structure. Hereinafter, a multilayer inductor will be described as an example.

The first problem is an increase in the DC resistance value. In order to reduce the DC resistance, where the resistance of the inner conductor is the largest, the cross-sectional area should be increased and the overall length should be shortened. However, the length of the inner conductor is determined by the outer dimensions and the number of turns of the multilayer inductor. Therefore, the change is substantially difficult. For this reason, the cross-sectional area of the internal conductor has been exclusively increased.
However, if the width of the conductor is increased and the cross-sectional area is increased, the cross-sectional area of the magnetic path is reduced, so that the inductance value is reduced, and if the thickness is increased, the sheet lamination method results in insufficient crimping between the sheets at the time of lamination. There is a problem such as easy delamination (delamination), and the printing method has a problem of increasing man-hours because it is necessary to print a magnetic material around the conductor to compensate for the thickness of the conductor. .

  In order to deal with such a problem, in Patent Document 1 and Patent Document 2, two sheets each having a coil pattern (61a, 61b... 66a, 66b) are overlapped and connected through a through hole. A multilayer electronic component in which is formed is disclosed (see FIG. 16). According to this configuration, it is not necessary to increase the thickness of the conductor or widen the width, but since the coil pattern of about 6 patterns is prepared and used, the problem of increasing the number of steps is still solved. Not.

  The second problem is DC superposition characteristics. Conventional winding type inductors have an open magnetic circuit structure, but multilayer inductors have a closed magnetic circuit structure (see FIG. 17). Therefore, when a large excitation current (also referred to as a superimposed current) is passed, the magnetic body 80 becomes magnetic. In some cases, the inductance rapidly decreases due to saturation. The DC superimposition characteristic is particularly problematic when used for a DC-DC converter.

The third problem is a decrease in the quality factor Q. In the conventional multilayer inductor shown in FIG. 17, a magnetic flux φb is formed inside by an exciting current flowing through the internal conductor 60, and a leakage magnetic flux φa is formed around the internal conductor 60 surrounded by a magnetic material. Arise. Since the direction of the current flowing through the internal conductor 60 is the same, the direction of the leakage magnetic flux φa of each coil pattern is reversed, increasing the magnetic resistance, reducing the inductance value and reducing the quality factor Q.
Japanese Utility Model 05-57817 JP-A-08-130115

  As described above, the conventional multilayer inductor still has various problems. Accordingly, in the present invention, in a multilayer electronic component such as a multilayer inductor or a multilayer substrate incorporating the inductor, the first step is to obtain a multilayer electronic component having an excellent Q value by reducing the DC resistance value while reducing the number of manufacturing steps. The purpose. It is a second object of the present invention to obtain a laminated electronic component with a small variation in inductance value due to an exciting current.

The present invention provides a plurality of first conductor patterns and second conductor patterns that are overlapped via a first insulator layer and connected in parallel by a plurality of via holes provided in the first insulator layer. In the laminated electronic component having a coil pattern, the first conductor pattern constituting the first coil pattern is connected to one end of the second conductor pattern by a via hole overlapping in the lamination direction, and the second conductor pattern Are connected by via holes at a plurality of locations between one end and the other end of the second conductor pattern, the other end of the second conductor pattern is not connected, the other end of the second conductor pattern is The first conductor pattern constituting the second coil pattern is connected to the via hole provided in the second insulator layer, and the first coil pattern and the second coil pattern are connected in series to form a spiral. Coil formed into a shape A laminated electronic component, characterized in that the.
In the present invention, the first conductor pattern is a conductor pattern formed in approximately 3/4 turns to approximately one turn, and the second conductor pattern is a conductor pattern formed in approximately one turn. Is preferred .

In the present invention, in at least a part of the coil pattern, one of the first insulator layer and the second insulator layer is a magnetic body and the other is a non-magnetic body to form a magnetic gap. Is preferred.

Further, in the present invention, in at least a part of the coil pattern, a third insulator layer is disposed in an inner region thereof, the first and second insulator layers are formed of a magnetic material, and the third insulator layer is formed. It is also preferable to form the magnetic gap by forming the insulator layer from a non-magnetic material.

  Since the first and second conductor patterns are connected in parallel by a plurality of via holes, the DC resistance of the coil can be reduced, and loss can be reduced. Further, the magnetic flux generated in the first insulator layer can be reduced and the Q value can be improved. In addition, many parts of the coil can be formed with the coil pattern formed by the first and second conductor patterns, reducing the man-hours compared to the prior art and reducing equipment such as screens for printing. I can do it.

  In the present invention, it is preferable that the first insulator layer is a non-magnetic material and the second insulator layer is a magnetic material. According to such a configuration, the first insulator layer can be a magnetic gap (also referred to as an air gap). In this case, a non-magnetic material is disposed in the inner and outer regions of the coil, and an open magnetic circuit structure is obtained in which the magnetic current is not easily saturated by the demagnetizing field. Therefore, a stable inductance value can be obtained from a low excitation current to a high excitation current, and excellent DC superposition characteristics that do not easily cause magnetic saturation even when a large current is passed can be exhibited. Further, if the first insulator layer is made of a non-magnetic material, the space between the first conductor pattern and the second conductor pattern is occupied by the non-magnetic material, so that the leakage magnetic flux can be reduced and thus has a high Q. It can be a coil.

  In addition, if a third insulator layer is disposed in the inner region of the coil pattern, and this is used as a non-magnetic material to form a magnetic gap only on the inner side of the coil, a magnetic gap is provided on the inner and outer sides of the coil. In addition, a larger inductance can be obtained, and no magnetic gap is formed on the outside, so that no leakage magnetic flux is generated. Also in this case, the magnetic gap can reduce the magnetic flux leaking between the first conductor pattern and the second conductor pattern, and a coil having a high Q can be obtained.

  In the present invention, the thickness of the first insulator layer is preferably thinner than the thickness of the second insulator layer. Also in this case, the leakage magnetic flux can be further reduced. Preferably, the thickness of the first insulator layer is preferably 1/8 to 1/2 of the thickness of the second insulator layer.

  In the present invention, the width of the first conductor pattern and / or the second conductor pattern constituting a part of the coil pattern is set to the width of the first conductor pattern and the second conductor pattern constituting the other coil pattern. Instead, it may be wider. According to such a configuration, a large inductance can be obtained at a low current, and a coil current portion having a wide conductor pattern functions as a magnetic gap after magnetic saturation occurs at a large current. It can exhibit excellent DC superposition characteristics that are not easily magnetically saturated even when flowing. Since the cross-sectional area of the magnetic path may be demagnetized to cause a decrease in inductance, the width dimension of the coil pattern is appropriately set depending on the required inductance.

  By mounting a semiconductor integrated circuit component on the surface and connecting the semiconductor integrated circuit component and the coil, the mounting area on the circuit board can be reduced by the amount of the semiconductor integrated circuit component, and the connection lines to be provided on the circuit board can be reduced. This is preferable because it is possible.

  According to the present invention, in a multilayer electronic component such as a multilayer inductor or a multilayer substrate incorporating an inductor, the direct current resistance value is low and the inductance value varies little by the excitation current, so that it can cope with a large excitation current. The quality factor Q can be improved.

Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof.
FIG. 1 is a perspective view of a multilayer electronic component (multilayer inductor) according to an embodiment of the present invention. 2A to 2I are perspective views for explaining the laminated structure of the laminated electronic component. FIGS. 3A to 3I are perspective views for explaining a laminated structure of another laminated electronic component. FIG. 4 is an exploded perspective view showing another example of a coil pattern used for a laminated electronic component.

The multilayer inductor is mainly composed of a first insulator layer 10 on which a first conductor pattern 1 is formed and a second insulator layer 11 on which a second conductor pattern 2 is formed. The first conductor pattern 1 and the second conductor pattern 2 are formed in a band shape, and at least the second conductor pattern 2 is formed in an annular shape.
In the present embodiment (FIG. 2), the first conductor pattern is formed in a 3/4 turn ring shape, the second conductor pattern is formed in a ring pattern having substantially one turn, and the first insulator layer is formed on the first insulator layer. The direct current resistance is reduced by connecting conductor patterns with a plurality of via holes provided. Even if the first conductor pattern has less than 3/4 turns, the effect of reducing the direct current resistance value is exhibited as compared with the prior art.
Further, as shown in the exploded perspective view of FIG. 3, the first conductor pattern is also formed into an annular pattern having substantially one turn, and the coil patterns are connected by a plurality of via holes provided in the second insulator layer. It is preferable to do this. In the multilayer inductor of FIG. 3, the lead electrode patterns 4a and 4b are wide and connected to the coil pattern by a plurality of via holes, and the via holes extend to the upper and lower surfaces and are electrically connected to external terminals. With such a configuration, the number of connection points between the electrode patterns formed inside and the external terminals is increased, and problems such as disconnection do not occur, thereby improving the connection reliability.

The first conductor pattern and the second conductor pattern are each printed on the insulator layer. If the thickness of the conductor pattern is large, the DC resistance value is also reduced, but the same problem as in the prior art occurs. On the other hand, if the thickness is too thin, the direct current resistance value is not sufficiently reduced. Therefore, the thickness of each conductor pattern is preferably 10 μm to 20 μm. Further, the first and second conductor patterns may be formed with different thicknesses.
According to the present invention, it is possible to suppress an increase in the DC resistance value even when the conductor pattern is thin, and to suppress the occurrence of delamination. Further, since the coil can be formed substantially by two conductor patterns, the screen for forming the conductor pattern can be reduced, and the man-hour and cost for forming the coil can be reduced.

  As shown in FIG. 4, the positions of via holes connecting between the conductor patterns and the coil patterns, that is, the positions of the internal connections can be different from each other. The via hole is filled with a conductive paste such as Ag. According to such a configuration, the via hole is less likely to be continuous in the stacking direction, and the pressure at the time of stacking pressure bonding is dispersed without concentrating on the via hole portion. Thus, the pressure-bonding pressure can be applied to the laminate more uniformly, and the occurrence of problems such as delamination can be reduced.

Hereinafter, the procedure of the lamination process of the laminated electronic component will be described with reference to FIG. First, an insulator sheet (not shown) formed on a carrier film (not shown) obtained by a known sheet forming technique such as a doctor blade method is prepared. This insulator sheet is cut into a predetermined shape together with the carrier film, and this is placed on a plate to hold the carrier film side by suction. The insulator sheet constitutes the insulator layer 16 ((i)). The insulator sheet only needs to have a thickness that prevents the magnetic flux generated by the coil from leaking to the outside, and the thickness after firing is 5 μm to 100 μm.
Next, another insulator sheet (which constitutes the insulator layer 15) is stacked and pressure-bonded so that the carrier film faces upward, and the carrier film is peeled off. A plurality of lead electrode patterns 4a are formed on this insulator sheet, and connection via holes (indicated by black circles in the figure) are formed. The insulator sheet only needs to have such a thickness that the magnetic flux generated by the coil in cooperation with the insulator layer 16 does not leak to the outside, and the thickness after firing is 5 μm to 25 μm ((h)). .

Next, another insulator sheet (which constitutes the first insulator layer 10) is stacked and pressure-bonded so that the carrier film is on top, and the carrier film is peeled off. A plurality of first electrode patterns 1 are formed on the insulator sheet ((g)). The thickness of the insulator sheet is preferably thinner than the second insulator layer so as to reduce the leakage magnetic flux, and is formed with a thickness of 5 μm to 15 μm.
Next, another insulator sheet (which constitutes the second insulator layer 11) is stacked and pressure-bonded so that the carrier film faces upward, and the carrier film is peeled off. A plurality of second electrode patterns 2 are formed on this insulator sheet ((f)). The thickness of the insulator sheet is 5 μm to 25 μm. A plurality of via holes filled with a conductor pattern such as Ag are formed in the insulator sheet constituting the first insulator layer 10, and the first electrode pattern 1 and the second electrode holes 2 are formed by the via holes (black circles in the figure). The electrode pattern 2 is connected at a plurality of locations to form one coil pattern 3. At least two connection points are formed, but it is preferable to provide more connection points in order to make the potentials of the first and second electrode patterns the same.

  Furthermore, the insulator sheet constituting the first insulator layer 10 and the insulator sheet constituting the second insulator layer 11 are overlapped to form another coil pattern ((b), (c), (d), ( e)), the coil patterns were connected by a plurality of via holes provided in the insulator sheet constituting the second insulator layer 11, and this was repeated a predetermined number of times to form a coil that was spirally wound. .

Next, another insulator sheet (which constitutes the insulator layer 15) is laminated and pressure-bonded so that the carrier film is on top, and the carrier film is peeled off. A plurality of lead electrode patterns 4b are formed on the insulator sheet.
In addition, the other electrode pattern 5 ((b) ′, (c) ′) excluding the portion that does not contribute to the connection by changing the coil pattern ((b), (c)) located at the end of the coil It is also good. In this case, since the amount of expensive noble metal such as Ag can be reduced, production costs can be reduced.

The obtained laminate is cut at a predetermined interval so that the laminate has a predetermined dimension, for example, 2.0 mm × 1.25 mm × 1.0 mm after sintering, and the conductor pattern 4a is formed on the opposite side surface. It was set as the laminated body of the piece which exposed the edge part of 4b. This was sintered at 850 ° C. to 950 ° C. for 2 to 6 hours in the air, then barrel-polished, and paste such as Ag was applied to the side surface of the laminate on which the electrode pattern appeared, and baked to external terminals 20a and 20b. And formed. When the conductor pattern diffuses into the insulator layer, the binder is removed in the air, and the firing is performed in a reduced oxygen atmosphere in which the firing atmosphere has an oxygen partial pressure of 8% or less, or reduction with N ₂ or Ar substituted. It may be an atmosphere.

In the present invention, the first and second insulator layers are mainly made of a magnetic material. In the case of forming the magnetic gap layer, a part thereof is formed using a non-magnetic material (a dielectric material or a magnetic material that loses magnetism at a low temperature).
In the present invention, soft ferrite is used as the magnetic material. This soft ferrite is appropriately selected according to the magnetic properties (initial permeability, loss, quality factor, etc.) required for laminated electronic components, but it has a large specific resistance and relatively low loss. Ni-Zn ferrite is often used.
As other ferrites, Mg—Zn ferrite containing Fe ₂ O ₃ , ZnO, MgO (part of which may be replaced by CuO) as a main component, Fe ₂ O ₃ , ZnO, LiO (partly CuO) Li—Zn ferrite containing as a main component may be used. If it is Mg—Zn ferrite, an inexpensive multilayer electronic component can be obtained without using expensive Ni. Moreover, if it is Li-Zn ferrite, it can be set as a multilayer inductor with little deterioration of the magnetic characteristic by magnetostriction.

Moreover, it is preferable to use the ceramic material which has any one of a zirconium silicate, a calcium zirconate, and a zirconium as a dielectric material which is a nonmagnetic material. In the case where an insulator layer using a dielectric and an insulator layer made of soft ferrite are combined, a material having a smaller difference in linear expansion coefficient than the conductor material constituting the conductor pattern is selected. The linear expansion coefficient of the ceramic material is 4 ppm / ° C. for zirconium silicate, 9.6 ppm / ° C. for calcium zirconate, and 8 ppm / ° C. for zirconium. By using the ceramic material or the like, generation of internal stress can be suppressed. It is also preferable to select a dielectric that has poor reactivity with the magnetic material.
When a laminated inductor is composed of first and second insulator layers formed of a magnetic material or a non-magnetic material, the difference in linear expansion coefficient is suppressed to a small value by selecting a material, so that the magnetism due to magnetostriction of ferrite is reduced. It is possible to reduce fluctuations in characteristics and suppress the occurrence of internal cracks. When a low melting point metal such as Ag is used for the conductor pattern, by adding a low-temperature sintering accelerator such as Bi ₂ O ₃ , CuO, or ZnO to the above-described dielectric, firing at a temperature of about 900 ° C. Even if it exists, sintering can be accelerated | stimulated and it can densify.

As another nonmagnetic material, there is a magnetic material that loses magnetism at the actual use temperature because the Curie temperature Tc is low, and the initial permeability is substantially 1. The Curie temperature Tc varies depending on the amounts of Fe ₂ O ₃ and ZnO, which are the main components of ferrite. For example, in order to set the Curie temperature Tc to −40 ° C. or less, Fe ₂ O having 40 to 55 mol% of the main component is used. ₃ , 40 mol% or more of ZnO, the remainder may be CuO-Zn ferrite of CuO.

  The conductor material constituting the conductor pattern and the external terminal is preferably low in resistivity and low in cost, but is selected from an alloy containing at least one of Pt, Pd, Au, Cu, and Ni in addition to Ag. May be. Depending on the selection of the conductor material, the firing temperature may be 100 ° C. or higher, or the firing atmosphere may need to be limited to a reducing atmosphere. In particular, when a reducing atmosphere is used, the specific resistance may decrease due to the formation of a different phase due to the reduction of the magnetic material or dielectric that constitutes the insulator layer, so that attention must be paid.

FIG. 5 is a cross-sectional view of a multilayer inductor configured using a nonmagnetic material for the first insulator layer 10 and a magnetic material for the second insulator layer 11. According to this embodiment, since the first insulator layer 10 becomes a magnetic gap, the magnetic flux generated by the first conductor pattern 1 and the second conductor pattern 2 constituting the coil pattern 3 is a non-magnetic material. It hardly passes through the first insulator layer 10. In addition, since the magnetic flux φa that circulates around the coil pattern 3 and the magnetic flux φb interlinked with other coil patterns are also reduced, the inductance value is reduced, but the reduction can be suppressed to the Q value and the DC resistance value is low. In addition, it is possible to obtain a multilayer inductor excellent in direct current superposition, in which the inductance value varies little depending on the excitation current.
FIG. 6 is a cross-sectional view of a multilayer inductor configured using a magnetic material for the first insulator layer 10 and a non-magnetic material for the second insulator layer 11. Also in this case, a multilayer electronic component having a low DC resistance value and a small variation in inductance value due to the excitation current and excellent in DC superposition can be obtained.
The above-described multilayer inductor has a configuration in which all coil patterns are provided with a magnetic gap. However, even if a magnetic gap is formed only in a part, an excellent effect can be obtained.

In the above embodiment, the procedure for creating the coil pattern by the sheet method is shown, but part or all of the coil pattern can be formed by using the printing method. FIG. 7 is a diagram showing a procedure for forming a coil pattern by a sheet method.
An insulator sheet ((a)) that includes the via hole H1 and that constitutes the second insulator layer 11 on which the second conductor pattern 2 is formed is prepared. From there, an insulator paste to be the first insulator layer 10 is printed on almost the entire surface of the second insulator layer 11 ((b)). An opening is provided so that a part of the second conductor pattern 2 appears at the time of printing, and the first conductor pattern 1 is printed and formed so as to overlap the portion ((c)). The opening becomes a via hole H2 and connects the first conductor pattern 1 and the second conductor pattern 2 in a direct current manner. In addition, after printing a conductor pattern or an insulator paste, drying is appropriately performed. Note that the insulator sheet constituting the second insulator layer 11 may be formed by printing in the same manner as the first insulator layer 10.

FIG. 8 is a diagram showing another procedure for forming a coil pattern by the sheet method. An insulator sheet ((a)) that includes the via hole H1 and that constitutes the second insulator layer 11 on which the second conductor pattern 2 is formed is prepared. A non-magnetic paste was printed on the inner region of the second conductor pattern 2 to form a magnetic gap layer 17 (third insulator layer) ((b)). Furthermore, except for the third insulator layer, an insulator paste made of a magnetic material was printed to form the first insulator layer 10. At this time, a part of the second conductor pattern 2 and an inner region of the second conductor pattern 2 are opened ((c)). Thereafter, the first conductor pattern 1 was printed ((d)) so as to overlap with the portion to form a coil pattern.
FIG. 9 shows a cross-sectional view of a multilayer inductor formed using this method. In this embodiment, the magnetic gap layer 17 is formed with a thickness defined by the first and second conductor patterns. However, the magnetic gap layer 17 can also be formed thinly. An insulator paste made of a magnetic material is printed.
With such a configuration, the magnetic gap layer 17 does not appear on the outer surface of the multilayer inductor. Therefore, a dielectric that does not become dense at the temperature at which the multilayer inductor is fired can be used for the magnetic gap layer.
In this case as well, it is formed by printing a paste-like dielectric, but after firing, at least a part of the dielectric is not densified and becomes powdery, so there is no need to consider the linear expansion coefficient so much. The choices spread. As the dielectric, in addition to the above-described dielectric _{materials, Li 2 O · Al 2 O} 3 · 4SiO 2, Li 2 O · Al 2 O 3 · 2SiO 2, SiO 2, TiO 2, WO 3, Ta 2 O ₅ , Nb ₂ O ₅ , Al ₂ O _{3 and the} like are raised.

FIG. 10 shows a cross section of the multilayer inductor when the width of the conductor pattern constituting a part of the coil pattern is made different from that of the other coil pattern and formed wide. According to such a configuration, the cross-sectional area of the magnetic path is partially different, and magnetic saturation occurs earlier in the part (small area part) where the cross-sectional area becomes smaller than in other parts. The area portion functions as a magnetic gap, and the DC superposition characteristics of the multilayer inductor can be improved.
FIG. 11 shows another example of a multilayer inductor having a small area portion. In this case, the width of only one conductor pattern of the coil pattern is changed, but the direct current superimposition characteristic can be improved similarly.

  In the present invention, as shown in FIG. 12, the electrode pattern may be formed by arranging strip-shaped electrodes side by side except for a part thereof, or a coil pattern formed by electrode patterns formed in three or more layers. May be formed.

FIG. 13 shows an external appearance of a DC-DC converter module configured by combining a laminated electronic component (laminated substrate) and a semiconductor integrated circuit component, FIG. 14 shows a cross section thereof, and FIG. 15 shows an equivalent circuit thereof.
The DC-DC converter module according to the present embodiment is a step-down DC-DC converter in which a semiconductor integrated circuit component 200 including a switching element and a control circuit is mounted on a laminated substrate 100 containing a coil composed of a plurality of coil patterns. is there. The semiconductor integrated circuit component is sealed with a resin 300.
A plurality of external terminals (not shown) are provided on the back surface of the multilayer substrate 100, and semiconductor integration is performed by connection electrodes 150 formed on the side surface (not shown), the front surface, and the inside (not shown) of the multilayer substrate. The circuit component 200 and the coil are connected.
In the equivalent circuit, Vcon is an output voltage variable control terminal, Ven is an output ON / OFF control terminal, Vdd is a terminal for ON / OFF control of the switching element, Vin is an input terminal, Vout is an output terminal, and GND is A ground terminal GND is shown.

  According to the multilayer substrate of the present embodiment, an excellent Q value can be obtained while reducing the number of manufacturing steps as in the multilayer inductor described above. When the magnetic gap layer is formed, the direct current superimposition characteristic is exhibited and the leakage magnetic flux to the outside is small. Therefore, even if the semiconductor integrated circuit 200 and the coil are arranged close to each other, the semiconductor integrated circuit No noise is generated in 200, and excellent conversion efficiency can be obtained as a DC-DC converter.

(First embodiment)
Examples of the present invention will be described in detail below. Since the structure of the multilayer inductor described in this embodiment is the same as that shown in FIG. 2, the contents shown in the previous description may be omitted as appropriate.
For the first insulator layer 1 and the second insulator layer 2, Fe ₂ O ₃ : 47.5 mol%, NiO: 19.7 mol%, CuO: 8.8 mol%, ZnO: 24.0 mol% are mainly used. As components, Bi ₂ O ₃ : 1 wt%, Co ₃ O ₄ : 0.08 wt%, SnO ₂ : 0.5 wt%, SiO ₂ : 0.5 wt% are added and contained as subcomponents with respect to this main component. Ferrite material was used.

The oxides were weighed and mixed, calcined at 850 ° C. for 2 hours, and the calcined body was wet pulverized with a ball mill to obtain a ferrite powder having a BET specific surface area of 7.0 m ² / g. To this, after kneading in a ball mill together with a binder mainly composed of polyvinyl butyral and a solvent such as ethanol, toluene and xylene to prepare a slurry, the viscosity is adjusted, and then a doctor blade method or the like on a resin film such as a polyester film. A ferrite green sheet having a thickness of 15 μm and 20 μm after coating and drying was prepared.

Next, an Ag paste is printed on the ferrite green sheet for each insulator layer to form a conductor pattern for forming a coil, and a sheet for the first insulator layer and a sheet for the second insulator layer are formed. Created a sheet. Each sheet has a via hole for electrical connection.
The obtained sheets for the first and second insulator layers were sequentially laminated so as to form a 5-turn coil, and these were pressed to form a laminate. A magnetic gap layer was formed by printing a non-magnetic paste on the inner region of the second conductor pattern 2. The obtained laminate was cut into a predetermined size (size after sintering: 2.0 mm × 1.25 mm × 1.0 mm), and after debinding, it was fired in the atmosphere at 900 ° C. for 3 hours. A conductive paste containing Ag as a main component was applied to the side where the conductor pattern was exposed, and baked at about 600 ° C. to form an external terminal, and a multilayer electronic component with a built-in 5-turn coil was created. . In addition, the thickness (after baking) of the 1st conductor pattern and the 2nd conductor pattern is respectively the same as 15 micrometers.

(Second embodiment)
In this example, as the first insulator layer 10, a sheet formed of a nonmagnetic ferrite material having an initial permeability μi of substantially 1 in the operating temperature range was used. _{Composition, Fe 2 O 3: 53mol%} , CuO: 3mol%, ZnO: a 44 mol%. The cross section of the obtained multilayer inductor is substantially the same as the cross section of the multilayer electronic component shown in FIG. Since other conditions are the same as those in the first embodiment, description thereof is omitted.

(First comparative example)
As a comparative example, a ferrite green sheet having a thickness after drying of 30 μm (the total thickness of the first and second insulator layers in the example) was prepared, and an Ag paste was printed on the sheet to form a conductor pattern for forming a coil. The magnetic gap layer was formed by printing a non-magnetic paste on the inner region of the conductor pattern. The obtained sheets were sequentially laminated so as to form a 5-turn coil, and this was crimped to form a laminate. The obtained multilayer body was cut and fired in the same manner as in Example 1, and then an external terminal was formed to produce a multilayer inductor incorporating a 5-turn coil. The thickness of the conductor pattern is 15 μm (same as the first conductor pattern).

(Second comparative example)
As another comparative example, a ferrite green sheet having a thickness after drying of 15 μm (thickness of the second insulator layer of the example) was prepared, and an Ag paste was printed thereon to form a conductor pattern. A magnetic gap layer was formed by printing a non-magnetic paste in the region. After drying, a ferrite paste was printed around the conductor pattern and dried to prepare a sheet. The obtained sheets were sequentially laminated so as to form a 5-turn coil, and this was crimped to form a laminate. The obtained multilayer body was cut and fired in the same manner as in Example 1, and then an external terminal was formed to produce a multilayer inductor incorporating a 5-turn coil. The thickness of the conductor pattern is 30 μm (the same as the sum of the first conductor pattern and the second conductor pattern).

  100 DC resistance values of the obtained multilayer inductors were evaluated using a tester. The inductance value and Q value were evaluated using an LCR meter. The results are shown in Table 1. According to this example, it was possible to obtain a DC resistance value equivalent to that of a conventional multilayer inductor constituted by a thick conductor pattern. Moreover, the thing which provided the magnetic gap showed the outstanding direct current | flow superimposition characteristic. In addition, a 10-sample SEM was used to observe the cross section of the coil periphery, but there was no occurrence of cracks or the like, and no structural defect occurred.

  According to the present invention, in a multilayer electronic component such as a multilayer inductor or a multilayer substrate incorporating the inductor, the DC resistance value can be reduced and the multilayer electronic component having an excellent Q value can be obtained while reducing the number of manufacturing steps. Furthermore, it is possible to obtain a multilayer electronic component with a small variation in inductance value due to the excitation current.

1 is a perspective view of a multilayer electronic component according to an embodiment of the present invention. 1 is an exploded perspective view of a multilayer electronic component according to an embodiment of the present invention. It is a disassembled perspective view of the multilayer electronic component which concerns on the other Example of this invention. It is a partial exploded perspective view of the multilayer electronic component which concerns on the other Example of this invention. It is sectional drawing of the multilayer electronic component which concerns on the other Example of this invention. It is sectional drawing of the multilayer electronic component which concerns on the other Example of this invention. It is a partial exploded perspective view of the multilayer electronic component which concerns on the other Example of this invention. It is a partial exploded perspective view of the multilayer electronic component which concerns on the other Example of this invention. It is sectional drawing of the multilayer electronic component which concerns on the other Example of this invention. It is sectional drawing of the multilayer electronic component which concerns on the other Example of this invention. It is sectional drawing of the multilayer electronic component which concerns on the other Example of this invention. It is a perspective view of the conductor pattern used for the multilayer electronic component which concerns on the other Example of this invention. It is a perspective view of the multilayer electronic component (DC-DC converter module) which concerns on the other Example of this invention. It is sectional drawing of the multilayer electronic component (DC-DC converter module) which concerns on the other Example of this invention. It is an equivalent circuit of the multilayer electronic component (DC-DC converter module) which concerns on the other Example of this invention. It is a disassembled perspective view of the conventional multilayer electronic component. It is sectional drawing of the other conventional multilayer electronic component.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st conductor pattern 2 2nd conductor pattern 3 Coil pattern 10 1st insulator layer 11 2nd insulator layers 60a-65a, 60b-65b Conductor pattern 80 Magnetic body layer 100 Multilayer electronic component 200 Semiconductor integrated circuit Parts φa, φb Magnetic flux

Claims (7)

A plurality of coil patterns formed by connecting in parallel a plurality of via holes provided in the first insulator layer, the first conductor pattern and the second conductor pattern overlapping via the first insulator layer; In laminated electronic components,
First conductor patterns constituting the first coil pattern is connected with heavy Do Ri via hole to an end and the stacking direction of the second conductor pattern, one end and the other end of the second conductor pattern Is connected with via holes at a plurality of locations between the parts, the other end of the second conductor pattern is not connected,
The other end portion of said second conductive pattern is connected with the first conductor pattern and a via hole provided on the second insulator layer constituting the second coil pattern, the first coil pattern, A laminated electronic component, wherein the coil is formed in a spiral shape by connecting the second coil pattern in series. The first conductor pattern is a conductor pattern formed in approximately 3/4 turn to approximately 1 turn,
2. The multilayer electronic component according to claim 1, wherein the second conductor pattern is a conductor pattern formed in substantially one turn . The magnetic gap is formed by forming one of the first insulator layer and the second insulator layer as a magnetic body and the other as a non-magnetic body in at least a part of the coil pattern. Item 3. The laminated electronic component according to Item 1 or 2 . In at least a part of the coil pattern, a third insulator layer is disposed in an inner region of the coil pattern, the first and second insulator layers are formed of a magnetic material, and the third insulator layer is nonmagnetic. 3. The multilayer electronic component according to claim 1, wherein the laminated electronic component is formed of a body to form a magnetic gap .   5. The multilayer electronic component according to claim 1, wherein the thickness of the first insulator layer is thinner than the thickness of the second insulator layer.   The width of the first conductor pattern and / or the second conductor pattern constituting a part of the coil pattern is wider than the width of the first conductor pattern and the second conductor pattern constituting the other coil pattern. 6. The multilayer electronic component according to claim 1, wherein the multilayer electronic component is provided.   7. The multilayer electronic component according to claim 1, wherein a semiconductor integrated circuit component is mounted on a surface, and the semiconductor integrated circuit component and the coil are connected.

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