JP6414376B2 - Ceramic electronic components - Google Patents

Description

The present invention relates to a ceramic electronic component, and more particularly, to a ceramic electronic component such as a common mode choke coil using co-firing capable ferrite ceramic composition of the conductive material mainly composed of Cu.

  Conventionally, a common mode choke coil has been widely used to remove common mode noise generated between signal lines and power lines of various electronic devices and GND (ground).

  In this common mode choke coil, the noise component is transmitted in the common mode and the signal component is transmitted in the normal mode. Therefore, using the difference between these transmission modes, the noise is separated into the signal and noise. Yes.

  On the other hand, ceramic electronic parts using ferrite-based ceramics having a spinel crystal structure such as Ni—Zn are also widely used, and conventionally, ferrite materials have been actively developed.

For example, Patent Document 1 includes a magnetic part made of a ferrite material and a conductive part mainly composed of Cu, and the magnetic part is a divalent containing trivalent Fe and at least divalent Ni. In addition to the element, the Fe content is ₂₀ to 48% in terms of molar ratio in terms of Fe ₂ O ₃ , and the ratio of Mn to the total of Fe and Mn is Mn ₂ O ₃ In addition, a ceramic electronic component in which the magnetic body portion contains the Mn has been proposed so as to be converted into Fe ₂ O ₃ and a molar ratio of less than 50% (including 0%).

In Patent Document 1, the specific resistance ρ can be improved even if the Cu-based material and the ferrite material are simultaneously fired. In the laminated coil component in which the coil conductor is wound in the lamination direction, a specific resistance of 10 ⁵ or more is obtained. It is possible to ensure the insulation performance having ρ.

International Publication No. 2011/108701 (Claim 1, paragraph numbers [0037], [0077] to [0084], etc.)

  In Patent Document 1, a conductive paste containing Cu is applied to a magnetic sheet to form a coil pattern and a via conductor, and then a plurality of magnetic sheets on which the coil pattern and the via conductor are formed are laminated, After performing the degreasing process, the component body in which the internal conductor is embedded is manufactured by performing a baking process.

The degreasing treatment is performed in order to eliminate or remove the organic binder contained in the magnetic material sheet or the conductive paste. However, the degreasing treatment is performed with an oxygen concentration of Cu− so that Cu serving as a coil conductor is not oxidized. It is necessary to adjust the atmosphere below the Cu ₂ O equilibrium oxygen partial pressure.

However, when the degreasing treatment is performed in an atmosphere of Cu-Cu ₂ O equilibrium oxygen partial pressure or less, it is difficult to completely remove the organic binder. That is, the above-described degreasing treatment can remove the organic binder on the surface of the magnetic material and the vicinity of the surface, but it is difficult to completely remove the organic binder present in the magnetic material, and the carbon component in the organic binder remains. There is a risk. If the firing process is performed with the carbon component remaining inside the magnetic material in this way, the specific resistance ρ inside the magnetic material may be lower than that on the surface of the magnetic material or in the vicinity of the surface.

  In this case, when the coil conductor is embedded in the lamination direction as in the laminated coil component exemplified in Patent Document 1, the surface of the external electrode is sufficiently high because the specific resistance ρ in the surface of the magnetic body and in the vicinity of the surface is sufficiently high. When electroplating is applied to the film, a plating film such as a Ni film or a Sn film does not adhere to the surface of the magnetic material.

  However, in the case of a coil component in which a potential difference occurs between electrodes such as a common mode choke coil, the insulation performance can be sufficiently ensured if the specific resistance ρ inside the magnetic body decreases compared to the surface of the magnetic body or in the vicinity of the surface. There is a risk that reliability will be reduced.

The present invention has been made in view of such circumstances, and even when co-fired with a conductive material containing Cu as a main component, the internal specific resistance is not lowered, and sufficient insulation performance is ensured. it is an object of ceramic electronic components such as common mode choke coil having high reliability using the ferrite ceramic composition can.

The inventor conducted intensive research on a ferrite material having a spinel crystal structure represented by the general formula X ₂ O ₃ .MeO (X is Fe, Mn, Me is Zn, Cu, Ni). The amount of Fe ₂ O ₃ and Mn ₂ O ₃ is within a specific range after the amount is 5 mol% or less, and further contains a predetermined amount of a glass component containing Si, B, and an alkaline earth metal , and By adjusting the content of Si, B, and alkaline earth metal described above, a glass phase contributing to an improvement in specific resistance ρ can be sufficiently formed at the crystal grain boundary, whereby a Cu-based material and ferrite can be formed. Even if the materials are fired at the same time, not only the surface and the vicinity of the surface, but also the internal specific resistance ρ is sufficiently high to obtain a ferrite ceramic composition having desired good insulation while ensuring good magnetic permeability. If you can That knowledge was obtained. That is, even if this ferrite porcelain composition and a conductive material containing Cu as a main component are simultaneously fired, it is sufficient that the specific resistance ρ inside the ferrite porcelain composition can be suppressed as described above. Insulation performance can be ensured. Therefore, even in the case of a common mode choke coil or the like in which a potential difference is generated between the electrodes, it is possible to obtain high reliability with desired good electrical characteristics and magnetic characteristics and good insulation performance.

The present invention has been made on the basis of such knowledge. In the ceramic electronic component according to the present invention, a coil conductor has a first coil conductor and a second coil conductor, and the first coil conductor. Ceramic electronic component embedded in a component body so that the second coil conductor and the second coil conductor are opposed to each other with a certain separation distance, and the coil conductor is conductive with Cu as a main component. The component body is formed of a ferrite porcelain composition containing at least Fe, Mn, Ni, and Zn, and the ferrite porcelain composition has a Cu content molar amount converted to CuO. Table is 0 to 5 mol%, Fe and _Fe 2 _{O 3} molar content x mol% when converted into, and the molar content Ymol% when the converted to _Mn 2 _{O 3} Mn in (x, y) Te (X y) is A (30,1), B (47,1), C (47,7.5), D (45,7.5), E (45,10), F (35,10), G (35, 7.5) and H (30, 7.5) are surrounded by a glass component containing at least Si, B, and alkaline earth metal M, Fe, Mn, Ni, Zn and Cu are contained in the range of 1 part by weight or more and 5 parts by weight or less with respect to a total of 100 parts by weight when converted into Fe ₂ O _3, Mn ₂ O ₃ , NiO, ZnO and CuO, respectively , Each content of the B and the alkaline earth metal M is 20 to 55 wt% in terms of SiO ₂ , 10 to 20 wt% in terms of B ₂ O ₃ , and 25 to 60 wt% in terms of MO. It is characterized by.

As a result, the oxidation of Cu and the reduction of Fe ₂ O ₃ can be suppressed, and a glass phase can be formed at the crystal grain boundary. The specific resistance ρ can be kept high, and desired insulation performance can be ensured while ensuring good magnetic permeability . That is, it is possible to obtain a ceramic electronic component such as a common mode choke coil having desired good electric characteristics and magnetic characteristics and having high insulation performance and high reliability.

In the ceramic electronic component of the present invention, it is preferable that the alkaline earth metal contains at least one selected from Ba, Sr, Ca, and Mg.

In the ceramic electronic component of the present invention, the molar content of Zn is preferably 6 to 33 mol% in terms of ZnO.

As a result, a sufficient Curie point can be secured, and a ceramic electronic component can be obtained in which operation is guaranteed under conditions of high temperature during use while ensuring good magnetic permeability .

  In the ceramic electronic component of the present invention, the coil conductor and the component body are preferably fired at the same time.

  As a result, it is possible to obtain a ceramic electronic component having desired good electrical and magnetic characteristics even when co-fired with a Cu-based material, good insulation performance and high reliability.

Moreover, it is preferable that the ceramic electronic component of the present invention is fired in an atmosphere that is equal to or lower than the equilibrium oxygen partial pressure of Cu—Cu ₂ O.

  As a result, even if the coil conductor is sintered together with a ferrite porcelain composition that should be a component body using a conductive material containing Cu as a main component, Cu can be sintered without being oxidized. Further, it is possible to obtain a ceramic electronic component such as a common mode choke coil having good insulation performance and high reliability.

According to the ceramic electronic component of the present invention, the coil conductor has the first coil conductor and the second coil conductor, and the first coil conductor and the second coil conductor have a certain separation distance. A ceramic electronic component embedded in the component body so as to be opposed to each other , wherein the coil conductor is formed of a conductive material mainly composed of Cu, and the component body is at least Fe , Mn, Ni, and is formed by a ferrite ceramic composition containing Zn, the ferrite ceramic composition is 0 to 5 mol% molar content of Cu in terms of CuO, the Fe in the _Fe 2 _{O 3} molar content x mol% when converted, and the molar content Ymol% when the converted to _{Mn 2 O 3 Mn (x,} y) when expressed in, (x, y) is, a (30, 1), B (47, 1), C (47, 7.5), D (45, 7.5), E (45, 10), F (35, 10), G (35, 7.5), and H (30, 7.5) And glass components containing at least Si, B, and alkaline earth metal M are Fe, Mn, Ni, Zn, and Cu, respectively, Fe ₂ O _3, Mn ₂ O ₃ , NiO, ZnO, and CuO. It is contained in an amount of less than 5 parts by weight or more and 1 part by weight relative to total 100 parts by weight when converted into the Si, the B, and the content of the alkaline earth metal M, 20 respectively in terms of SiO ₂ ˜55 wt%, 10 to 20 wt% in terms of B ₂ O ₃ , and 25 to 60 wt% in terms of MO. Therefore, this ferrite porcelain composition and a conductive material containing Cu as a main component are simultaneously fired. or even Cu are oxidized from _Fe 2 _{O 3} can be reduced Control can, moreover since it is possible to form a glass phase in the grain boundaries, not only on the surface or near the surface of the ferrite ceramic composition, it is possible to maintain a high internal resistivity [rho, ensure good permeability desired insulation performance can be ensured while. Therefore , even in the case of a common mode choke coil in which a potential difference is generated between the electrodes , it has good insulation performance and magnetic characteristics , and high reliability can be ensured.

Specifically, it is possible to reliably obtain a good insulation performance with a specific resistance ρ of 10 ⁷ Ω · cm or more.

It is a diagram showing the composition range of _Fe 2 _{O 3} and _Mn 2 _{O 3} of the ferrite ceramic composition according to the present invention. 1 is a perspective view showing an embodiment of a common mode choke coil as a ceramic electronic component according to the present invention. It is AA sectional drawing of FIG. FIG. 3 is an exploded perspective view of the component body of FIG. 2. 3 is a cross-sectional view of a specific resistance measurement sample manufactured in Example 1. FIG. It is a disassembled perspective view which shows the principal part of the said sample for specific resistance measurement.

  Next, an embodiment of the present invention will be described in detail.

The ferrite porcelain composition as one embodiment of the present invention has a spinel type crystal structure represented by the general formula X ₂ O ₃ .MeO, and is Fe ₂ O ₃ or Mn ₂ O which is at least a trivalent element compound. ₃ and ZnO and NiO which are divalent element compounds, CuO which is a divalent element compound as necessary, and a glass component which contains at least Si, B, and alkaline earth metal ing.

Specifically, in the present ferrite porcelain composition, the molar content of CuO is 0 to 5 mol%, and each molar content of Fe ₂ O ₃ and Mn ₂ O ₃ is Fe _{2 as} shown in FIG. x mol% of molar content of O _3, when the Ymol% of molar content of _Mn 2 _{O 3,} is a (x, y) is hatched portion X of a region surrounded by points A~ point H, the balance It is made of ZnO or NiO. Furthermore, the content of the glass component is 1 with respect to 100 parts by weight in total when Fe, Mn, Ni, Zn, and Cu are converted into Fe ₂ O _3, Mn ₂ O ₃ , NiO, ZnO, and CuO, respectively. It is said to be more than part by weight.

  Here, each point (x, y) of the points A to H indicates the following content molar amounts.

A (30,1), B (47,1), C (47,7.5), D (45,7.5), E (45,10), F (35,10), G (35, 7.5), and H (30,7.5)
Next, the reason why the respective molar amounts of CuO, Fe ₂ O ₃ , and Mn ₂ O ₃ are set in the above range will be described in detail.

(1) CuO content molar amount In Ni-Zn ferrite, the inclusion of CuO having a melting point as low as 1026 ° C in the ferrite porcelain composition enables firing at a lower temperature and improves the sinterability. Can do.

On the other hand, in the case of simultaneously firing a Cu-based material containing Cu as a main component and a ferrite material, Cu is easily oxidized to form Cu ₂ O when fired in an air atmosphere. It is necessary to bake in the atmosphere.

However, when firing in such a reducing atmosphere, if the molar content of CuO exceeds 5 mol%, CuO in the ferrite raw material is reduced and the amount of Cu ₂ O generated increases, and therefore the specific resistance ρ is reduced. There is a risk of lowering.

  Therefore, in the present embodiment, the blending amount is adjusted so that the molar amount of CuO is 5 mol% or less, that is, 0 to 5 mol%.

(2) Respective molar amounts of Fe ₂ O ₃ and Mn ₂ O _{3 By} reducing the amount of Fe ₂ O ₃ from the stoichiometric composition and substituting part of Fe with Mn, Mn ₂ O ₃ is contained. Therefore, it is possible to avoid a decrease in specific resistance ρ, and to improve insulation.

That is, in the case of the spinel crystal structure (general formula X ₂ O ₃ · MeO), the stoichiometric composition is the ratio of X ₂ O ₃ (X: Fe, Mn) to MeO (Me: Ni, Zn, Cu). Is 50:50, and X ₂ O ₃ and MeO are usually blended so as to have a substantially stoichiometric composition.

When co-firing a Cu-based material containing Cu as a main component and a ferrite material, Cu is easily oxidized to form Cu ₂ O when fired in an air atmosphere, so that reducing properties such that Cu does not oxidize. It is necessary to bake in the atmosphere. On the other hand, when Fe ₂ O ₃ which is the main component of the ferrite material is fired in a reducing atmosphere, Fe ₃ O ₄ is generated. Therefore, it is necessary to fire Fe ₂ O _{3 in} an oxidizing atmosphere.

However, from the relationship between the equilibrium oxygen partial pressure of Cu—Cu ₂ O and the equilibrium oxygen partial pressure of Fe ₃ O ₄ —Fe ₂ O ₃ , when firing at a temperature of 800 ° C. or higher, Cu metal and Fe ₂ O ₃ It is known that there are no areas where coexist.

That is, at a temperature of 800 ° C. or higher, when firing is performed with an oxygen partial pressure set in an oxidizing atmosphere that maintains the state of Fe ₂ O ₃ , Cu is also oxidized to produce Cu ₂ O. On the other hand, when firing is performed with an oxygen partial pressure set in a reducing atmosphere that maintains the state of Cu metal, Fe ₂ O ₃ is reduced to produce Fe ₃ O ₄ .

Since there is no region where Cu and Fe ₂ O ₃ coexist in this way, when firing in a reducing atmosphere in which Cu does not oxidize, Fe ₂ O ₃ is reduced to Fe ₃ O ₄ , so that the specific resistance ρ As a result, the electrical characteristics may be deteriorated.

However, Mn ₂ O ₃ becomes a reducing atmosphere at a higher oxygen partial pressure than Fe ₂ O ₃ in the temperature range of 800 ° C. or higher. Therefore, at an oxygen partial pressure equal to or lower than the equilibrium oxygen partial pressure of Cu—Cu ₂ O, Mn ₂ O ₃ becomes a strongly reducing atmosphere as compared with Fe ₂ O ₃ , and therefore Mn ₂ O ₃ is preferentially reduced and burned. The result can be completed. In other words, since _{the Mn} 2 _{O 3} it is preferentially reduced as compared with _{Fe 2 O 3, Fe 2 O} 3 it is possible to complete the baking process before being reduced to _Fe 3 _{O 4.}

Thus, by reducing the content molar amount of Fe ₂ O ₃ from the stoichiometric composition, by containing Mn ₂ O ₃ which is the same trivalent element compound in the ferrite ceramic composition, Cu—Cu ₂ Sintering is completed before Fe ₂ O ₃ is reduced because Mn ₂ O ₃ is reduced preferentially even if Cu-based material and ferrite material are co-fired below the equilibrium oxygen partial pressure of O Cu metal and Fe ₂ O ₃ can coexist more effectively. And it can avoid that specific resistance (rho) falls by this, and can improve insulation.

However, if the content molar amount of Fe ₂ O ₃ is less than 30 mol%, the content molar amount of Fe ₂ O ₃ is excessively decreased, and on the contrary, the specific resistance ρ is lowered, and desired insulation cannot be ensured.

In addition, when the molar amount of Mn ₂ O ₃ is less than 1 mol%, the molar amount of Mn ₂ O ₃ is excessively reduced, so that Fe ₂ O ₃ is easily reduced to Fe ₃ O ₄ and the specific resistance ρ Decreases, and sufficient insulation cannot be secured.

In addition, even when the molar content of Fe ₂ O ₃ exceeds 47 mol%, the molar content of Fe ₂ O ₃ becomes excessive and Fe ₂ O ₃ is easily reduced to Fe ₃ O ₄ , and the specific resistance ρ is reduced. It is lowered and sufficient insulation cannot be secured.

Further, even when the molar content of Mn ₂ O ₃ exceeds 10 mol%, a sufficiently large specific resistance ρ cannot be obtained, and insulation cannot be ensured.

Further, when the content molar amount of Fe ₂ O ₃ is 30 mol% or more and less than 35 mol%, and when the content molar amount of Fe ₂ O ₃ is 45 mol% or more and less than 47 mol%, Mn ₂ If the content molar amount of O ₃ exceeds 7.5 mol%, the specific resistance ρ is reduced on the contrary, and desired insulation cannot be secured.

Therefore, in the present embodiment, the molar amounts of Fe ₂ O ₃ and Mn ₂ O ₃ are adjusted so that the molar amounts are in a region surrounded by points A to H in FIG.

  Further, the present ferrite porcelain composition contains a glass component containing at least Si, B, and an alkaline earth metal typified by Ba, Sr, Ca, and Mg.

  That is, by containing the glass component in the ferrite porcelain composition, a glass phase can be formed at the crystal grain boundary by the firing treatment. The internal specific resistance ρ can also be kept high. As a result, even when used in ceramic electronic components such as common mode choke coils in which a potential difference occurs between the electrodes, it is possible to obtain a ferrite ceramic composition having good insulation performance and high reliability.

However, the content of the glass component is 1 weight with respect to a total of 100 parts by weight when Fe, Mn, Ni, Zn, and Cu are converted into Fe ₂ O _3, Mn ₂ O ₃ , NiO, ZnO, and CuO, respectively. It is necessary to contain more than part. When the content of the glass component is less than 1 part by weight relative to 100 parts by weight in total, a sufficient glass phase cannot be formed at the crystal grain boundary, and a desired high specific resistance ρ cannot be obtained.

  In addition, although the upper limit of content of a glass component is not specifically limited, From a viewpoint of ensuring magnetic permeability fully, 5 weight part or less is preferable with respect to 100 weight part in total.

Each molar content of ZnO and NiO ferrite ceramic composition is not limited in _{particular, Fe 2 O 3, Mn 2} O 3, and be appropriately set according to the molar content of CuO However, it is preferable to blend so that ZnO: 6 to 33 mol% and NiO: the balance.

  That is, if the ZnO content exceeds 33 mol%, the Curie point Tc is lowered, and there is a possibility that the operation at high temperature may not be guaranteed. Therefore, the ZnO content is preferably 33 mol% or less.

  On the other hand, ZnO has an effect of contributing to the improvement of the magnetic permeability μ, but in order to exert such an effect, the molar amount of ZnO needs to be 6 mol%.

  Accordingly, the molar content of ZnO is preferably 6 to 33 mol%.

Thus, the present ferritic ceramic composition is 0 to 5 mol% molar content of Cu in terms of CuO, the molar content x mol% when converted to Fe in _Fe 2 _{O 3,} and Mn Mn ₂ When the content molar amount ymol% in terms of O ₃ is expressed by (x, y), (x, y) is in a specific range surrounded by the points A to H described above, and at least When glass components containing Si, B, and alkaline earth metal M are converted to Fe ₂ M _3, Mn ₂ O ₃ , NiO, ZnO, and CuO, respectively, Fe, Mn, Ni, Zn, and Cu Since 1 part by weight or more is contained with respect to a total of 100 parts by weight, Cu can be prevented from being oxidized or Fe ₂ O ₃ can be reduced even when co-fired with a Cu-based material. That can form a phase From not only the surface and near-surface of the ferrite ceramic composition, it is possible to maintain a high internal resistivity [rho, it is possible to ensure a desired insulation performance.

Specifically, it is possible to reliably obtain a good insulation performance with a specific resistance ρ of 10 ⁷ Ω · cm or more.

  Moreover, it becomes possible to ensure desired favorable magnetic permeability by making content of the said glass component into 5 weight part or less with respect to the said total 100 weight part.

  In addition, by setting the molar amount of ZnO to 6 to 33 mol%, it has a good magnetic permeability and a sufficient Curie point, and operation under conditions of high temperature during use is guaranteed. A ceramic electronic component can be obtained.

The contents of Si, B, and alkaline earth metal M contained in the glass component are not particularly limited, but are preferably ₂₀ to 55% by weight in terms of SiO ₂ and 10 in terms of B ₂ O ₃ , respectively. The glass phase contributing to the improvement of the specific resistance ρ can be sufficiently formed at the crystal grain boundaries.

  Next, the ceramic electronic component using the ferrite porcelain composition will be described in detail.

  FIG. 2 is a perspective view showing an embodiment of a common mode choke coil as a ceramic electronic component according to the present invention, and FIG. 3 is a cross-sectional view taken along line AA of FIG.

  In the common mode choke coil, first to fourth external electrodes 2 a to 2 d are formed on both end faces of the component element body 1.

  That is, the component body 1 includes a first coil conductor 3 having a first inner conductor 3a and a second inner conductor 3b, and a second coil having a third inner conductor 4a and a second inner conductor 4b. The first coil conductor 3 and the second coil conductor 4 are embedded in the component body 1 so as to be opposed to each other with a certain separation distance.

  Specifically, in the first coil conductor 3, one end of the first inner conductor 3 a is electrically connected to the outer electrode 2 a and wound in a coil shape, and the other end is connected via the via conductor 10. It is connected to one end of the second inner conductor 3b. The second inner conductor 3b is appropriately bent, and the other end is electrically connected to the outer electrode 2b.

  In the second coil conductor 4, one end of the third inner conductor 4 a is electrically connected to the external electrode 2 c and wound in a coil shape, and the other end is connected to the fourth via the via conductor 11. Is connected to one end of the inner conductor 4b. The fourth inner conductor 4b is appropriately bent, and the other end is electrically connected to the outer electrode 2d.

And in this Embodiment, while the 1st and 2nd coil conductors 3 and 4 are formed with the electroconductive material which has Cu as a main component, the component element | base_body 1 is the ferrite porcelain composition of this invention mentioned above. Is formed. As a result, Cu is not oxidized and Fe ₂ O ₃ is not reduced, and the specific resistance ρ does not deteriorate inside the component body 1, and the insulation performance having a specific resistance ρ of 10 ⁷ Ω or more is good. A common mode choke coil having high reliability can be obtained.

  In addition, since Cu-based materials are used for the first and second coil conductors 3 and 4, migration can be avoided as much as Ag-based materials, and the insulation resistance can be reduced. Therefore, a common mode choke coil having high reliability can be obtained.

  FIG. 4 is an exploded perspective view of the component body 1.

  Hereinafter, the manufacturing method of the common mode choke coil will be described in detail with reference to FIG.

First, as ceramic raw materials, Fe ₂ O ₃ , ZnO, NiO, and CuO as necessary are prepared as main components, and further a Si—B—M—O glass component (M: alkaline earth metal) is added. prepare. Then, CuO is 0 to 5 mol%, satisfy the specific _{area Fe} 2 _{O 3} and _Mn 2 _{O 3} is enclosed at the point A~ point H in FIG. 1, and the content of the glass component, Fe, Mn, When Ni, Zn, and Cu are converted into Fe ₂ O _3, Mn ₂ O ₃ , NiO, ZnO, and CuO, respectively, the total amount is 100 parts by weight (preferably 5 parts by weight or less). Thus, each ceramic raw material and glass component are weighed.

  Next, these weighed products are put in a pot mill together with pure water and cobblestones such as PSZ (partially stabilized zirconia) balls, sufficiently mixed and pulverized wet, evaporated and dried, and then temporarily heated at a temperature of 700 to 800 ° C. Bake.

  Next, these calcined powders are again put into a pot mill together with an organic binder such as polyvinyl butyral, an organic solvent such as ethanol and toluene, and PSZ balls, and sufficiently mixed and pulverized to produce a ceramic slurry.

  Next, the ceramic slurry is formed into a sheet using a doctor blade method or the like, and magnetic ceramic green sheets (hereinafter simply referred to as “magnetic sheets”) 5a to 5j having a predetermined film thickness are produced.

  Next, a laser processing machine is used for the magnetic sheet 5d and the magnetic sheet 5f among these magnetic sheets 5a to 5j, and via holes 6a and 6b are formed at predetermined positions.

  Next, a conductive paste containing Cu as a main component (hereinafter referred to as “Cu paste”) is prepared. Then, screen printing is performed using the Cu paste, predetermined conductor patterns 7a to 7d and electrode patterns 8a to 8d are formed on the magnetic sheets 5d to 5g, and the via holes 6a and 6b are filled with the Cu paste. To do.

  After that, these magnetic sheets 5d to 5g are sequentially laminated, and the outer magnetic sheets 5a to 5c and 5h to 5j are arranged on both upper and lower main surfaces, and these are pressed and pressure-bonded and cut into predetermined dimensions. To produce a laminated molded body.

Next, this laminated molded body is supplied with a mixed gas of N ₂ —H ₂ —H ₂ O to a firing furnace, and the equilibrium oxygen partial pressure of Cu—Cu ₂ O is adjusted so that Cu does not oxidize. Degreasing treatment is performed for about 8 to 12 hours at ° C, and the equilibrium oxygen partial pressure of Cu-Cu ₂ O is adjusted so that Cu is not oxidized even if baking treatment is performed at 900 to 1050 ° C. Baking is performed at a temperature of about 2 hours to obtain a component body 1 in which the first and second coil conductors 3 and 4 are embedded.

  Next, an external electrode conductive paste mainly composed of Cu or the like is applied to the end face of the component element body 1, dried, and then baked at 900 ° C. to form first to fourth external electrodes 2 a to 2 d. Thus, a common mode choke coil is produced.

As described above, in the present embodiment, the first coil conductor 3 and the second coil conductor 4 are formed of a conductive material containing Cu as a main component, and the component body 1 includes the ferrite porcelain composition described above. And is fired in an atmosphere below the equilibrium oxygen partial pressure of Cu—Cu ₂ O, so that Cu can be sintered without being oxidized even when co-fired with a Cu-based material. Moreover, since a glass phase is formed at the crystal grain boundary, it is possible to obtain a common mode choke coil having good insulation performance and high reliability without deteriorating the specific resistance ρ inside the component body 1. It becomes possible.

  The present invention is not limited to the above embodiment. For example, in the above embodiment, the magnetic sheets 5a to 5j are produced from the calcined powder. For example, a printing process is performed on a PET film to form a magnetic coating film, and the magnetic coating film is formed on the magnetic coating film. A coil pattern which is a conductive film may be formed.

  Moreover, in the said embodiment, although the 1st and 2nd coil patterns 7a-7d are formed by screen printing, the preparation methods of these coil patterns are not specifically limited, For example, other methods, for example, plating You may form by thin film formation methods, such as a method, a transfer method, or sputtering.

  In the above embodiment, a ceramic electronic component in which a potential difference is generated between the electrodes, such as a common mode choke coil, has been described as an example. However, the present invention is suitable for use in simultaneous firing with a conductive material mainly composed of Cu. Needless to say, it can be used widely and can be applied to other ceramic electronic parts, for example, various coil parts in which a coil conductor is formed in the stacking direction and the coil conductor is embedded in a component body. .

  Next, examples of the present invention will be specifically described.

[Preparation of specific resistance measurement sample]
Glass powders A to D having a glass composition as shown in Table 1 were prepared.

Next, Fe ₂ O ₃ , Mn ₂ O ₃ , ZnO, CuO and NiO are prepared as ceramic raw materials, Fe ₂ O ₃ : 44 mol%, Mn ₂ O ₃ : 5 mol%, ZnO: 25 mol %, CuO: 2 mol%, and NiO: 24 mol%, and these ceramic raw materials were weighed.

  Next, these weighed materials are put into a ball mill together with pure water and PSZ balls, mixed and pulverized in a wet manner for 48 hours, evaporated and dried, and then calcined at a temperature of 750 ° C. for 2 hours to obtain a calcined powder. It was.

  Next, with respect to 100 parts by weight of the calcined powder, each of the glass powders A to D is added in the range of 0 to 7.5 parts by weight, and then charged into a ball mill together with PSZ balls. The mixture was pulverized by wet-time, and an acrylic binder (organic binder) was added to 8 wt% and mixed well to obtain a ceramic slurry.

  Next, using a doctor blade method, the ceramic slurry is formed into a sheet shape so as to have a thickness of 25 μm, and this is punched into a size of 50 mm in length and 50 mm in width, and as shown in FIG. -51f were produced.

  Next, Cu powder was mixed with an organic vehicle containing terpineol (organic solvent) and ethyl cellulose resin (binder resin), and kneaded with a three-roll mill to prepare a Cu paste.

  Next, of the magnetic sheets 51a to 51f, two magnetic sheets 51c and 51d are screen-printed using Cu paste to produce conductor patterns 52a and 52b having a predetermined shape on the surfaces of the magnetic sheets 51c and 51d. did.

  Then, the magnetic sheet 51c on which the conductor pattern 52a is formed and the magnetic sheet 51d on which the conductor pattern 52b is formed are superposed, and this is further laminated with the magnetic sheets 51a, 51b, 51e, 51f on which the conductor pattern is not formed. And heated to 60 ° C. and pressurized and pressed for 60 seconds at a pressure of 100 MPa to obtain a laminated molded body.

Next, this laminated molded body is supplied with a mixed gas of N ₂ —H ₂ —H ₂ O to a firing furnace, the oxygen partial pressure is adjusted so that Cu is not oxidized, and degreasing treatment is performed at a temperature of 600 ° C. for 10 hours. went. Specifically, the oxygen partial pressure of the firing furnace is adjusted so as to be 1/100 of 2.8 × 10 ⁻⁸ Pa which is the equilibrium oxygen partial pressure of Cu—Cu ₂ O at 600 ° C. Processed.

Then, the oxygen partial pressure was adjusted to 6.7 × 10 ⁻² Pa and fired at a temperature of 1000 ° C. for 2 hours to obtain a ceramic sintered body in which internal electrodes were embedded. Here, the oxygen partial pressure: 6.7 × 10 ^-2 Pa is the equilibrium oxygen partial pressure of Cu-Cu ₂ O at 1000 ° C., thereby to Cu is not oxidized Cu-Cu ₂ O average oxygen content of A baking treatment was performed by adjusting the pressure.

  Next, the ceramic sintered body was put into a pot together with pure water, and the ceramic sintered body was subjected to barrel treatment using a centrifugal barrel machine, whereby the internal electrode was exposed from the end face to obtain a component body.

  Next, a conductive paste for an external electrode containing Cu powder, glass powder, and an organic vehicle was prepared.

And after apply | coating the said conductive paste for external electrodes to both ends of a component element body and making it dry, it is 10 degreeC at the temperature of 900 degreeC in the baking furnace which adjusted oxygen partial pressure to 4.3 * 10 < ^-3 > Pa. A baking process was performed for a minute, and samples for specific resistance measurement of sample numbers 1 to 21 were produced. The oxygen partial pressure: 4.3 × 10 ⁻³ Pa is the equilibrium oxygen partial pressure of Cu—Cu ₂ O at a temperature of 900 ° C.

  The external dimensions of the specific resistance measurement sample were 3.0 mm in length, 3.0 mm in width, and 1.0 mm in thickness.

  FIG. 6 is a cross-sectional view of a specific resistance measurement sample, in which the internal electrodes 54a and 54b are embedded in the component body 53 such that the ends of the internal electrodes 54a and 54b are staggered, and the component body External electrodes 55a and 55b are formed on both end faces of 53, and are electrically connected to the internal electrodes 54a and 54b.

[Preparation of samples for permeability measurement]
A plurality of the above-described magnetic sheets on which no conductor pattern is formed are laminated so that the total thickness is 1.0 mm, heated to 60 ° C., and pressed and pressed at a pressure of 100 MPa for 60 seconds, and then A ceramic molded body was obtained by cutting into a ring shape so that the outer diameter 20 was mm and the inner diameter was 12 mm.

  Subsequently, the obtained ceramic molded body was degreased and fired under the same degreasing and firing conditions as described above, thereby obtaining ring-shaped samples for permeability measurement of sample numbers 1 to 21.

(Sample evaluation)
For each of the specific resistance measurement samples of sample numbers 1 to 21, a voltage of 50 V was applied to the external electrodes 55a and 55b for 30 seconds, and the current at the time of voltage application was measured. Then, the resistance was calculated from the measured value, and the logarithm logρ of the specific resistance (hereinafter referred to as “specific resistance logρ”) was calculated from the sample size.

  Moreover, each magnetic permeability measurement sample of sample numbers 1 to 21 is housed in a magnetic permeability measurement jig (manufactured by Agilent Technologies, 16454A-s), and an impedance analyzer (manufactured by Agilent Technologies, E4991A) is used. The magnetic permeability μ was measured at a measurement frequency of 1 MHz.

  Table 2 shows the glass types in the ferrite porcelain compositions of Sample Nos. 1 to 21, the content of the glass component with respect to 100 parts by weight of the calcined powder, the specific resistance logρ, and the magnetic permeability μ.

  Sample No. 1 had a specific resistance logρ as low as 6.4 because the ferrite porcelain composition contained no glass component. This is probably because the organic binder is not completely removed during firing and carbon remains inside the component body, resulting in a decrease in insulation performance.

  Sample Nos. 2, 7, 12, and 17 have a specific resistance logρ of the sample number because the content of the glass component in the ferrite porcelain composition is as small as 0.5 parts by weight with respect to 100 parts by weight of the calcined powder. Although it was larger than 1, it was 6.5 to 6.9 and less than 7.0, and it was found that a sufficient specific resistance logρ was not yet obtained. This is presumably because the glass component was too small, so that a glass phase was not sufficiently formed at the crystal grain boundaries, and insulation performance could not be secured sufficiently.

  On the other hand, the sample numbers 3 to 6, 8 to 11, 13 to 16, and 18 to 21 have a glass component content of 1 part by weight or more with respect to 100 parts by weight of the calcined powder. It was found that good results of 0.0 or more were obtained, and the permeability μ was 23 or more, so that practicality could be secured.

  However, as shown in sample numbers 6, 11, 16, and 21, when the content of the glass component exceeded 5 parts by weight with respect to 100 parts by weight of the calcined powder, the magnetic permeability μ decreased to 23 to 26. Therefore, in order to obtain better magnetic permeability μ, it was found that the content of the glass component is preferably 5 parts by weight or less with respect to 100 parts by weight of the calcined powder.

Fe ₂ O ₃ , Mn ₂ O ₃ , ZnO, CuO, and NiO are prepared as ceramic raw materials, and these ceramic raw materials are weighed so that the molar content is as shown in Tables 3 and 4. did. That is, the ceramic raw materials were weighed so that ZnO was kept constant at 25 mol% and CuO was kept at 2 mol%, the molar amounts of Fe ₂ O ₃ and Mn ₂ O ₃ were varied, and the balance was NiO.

  Next, these weighed materials are put into a ball mill together with pure water and PSZ balls, mixed and pulverized in a wet manner for 48 hours, evaporated and dried, and then calcined at a temperature of 750 ° C. for 2 hours to obtain a calcined powder. It was.

  Next, 3 parts by weight of the glass powder B is added to 100 parts by weight of the calcined powder, then charged into a ball mill together with PSZ balls, pure water is added and mixed and pulverized in a wet manner for 24 hours. A binder was added to 8 wt% and mixed well to obtain a ceramic slurry.

  Thereafter, samples for specific resistance measurement of sample numbers 31 to 94 were prepared by the same method and procedure as in [Example 1], and the specific resistance logρ was determined.

  Tables 3 and 4 show the ferrite composition and specific resistance logρ of the samples of sample numbers 31 to 94, respectively.

  Since the sample numbers 31 to 40, 44 to 47, 53 to 55, 61 to 63, 69 to 72, and 76 to 94 are outside the shaded area X in FIG. 1, the specific resistance logρ is less than 7.0. Therefore, the specific resistance logρ was small and the desired insulation could not be obtained.

  On the other hand, sample numbers 41 to 43, 48 to 52, 56 to 60, 64 to 68, and 73 to 75 are in the region surrounded by the hatched portion X in FIG. 1, and contain the molar amount of CuO and the glass component. Since the weight is also within the range of the present invention, it was found that the specific resistance log ρ is 7.0 or more, and good insulating properties can be obtained.

Fe ₂ O ₃ , Mn ₂ O ₃ , ZnO, CuO, and NiO were prepared as ceramic raw materials, and these ceramic raw materials were weighed so that the molar content was as shown in Table 5. That is, Fe ₂ O ₃ is 44 mol%, Mn ₂ O ₃ is 5 mol%, ZnO is 25 mol%, and the CuO content is varied in the range of 0 to 10 mol%, with the balance being NiO. Each ceramic raw material was weighed so that

  Thereafter, samples for specific resistance measurement of sample numbers 101 to 105 were prepared by the same method and procedure as in [Example 2], and the specific resistance logρ was determined.

  Table 5 shows the ferrite composition and specific resistance log ρ of each of the sample numbers 101 to 105.

  Sample Nos. 104 and 105 had a CuO content of 7.5 mol% and 10 mol%, respectively, and exceeded 5 mol%, so that the specific resistance logρ was 6.8 and 5.9, respectively. It became less than 0 and the insulation performance deteriorated.

In contrast, Sample Nos. 101 to 103 have a CuO content of 0 to 5 mol%, which is within the scope of the present invention, and the Fe ₂ O ₃ and Mn ₂ O ₃ content and the glass component content are also the same. Since it is within the scope of the present invention, the specific resistance log ρ is 7.3 to 7.7, and it has been found that good insulation performance can be obtained.

  A common mode choke coil as shown in FIG. 3 was prepared using the magnetic sheets of sample numbers 1 and 9 prepared in [Example 1], and the leakage voltage was measured to evaluate the sample.

  That is, using a laser processing machine, via holes were formed at predetermined locations on the magnetic sheets of sample numbers 1 and 9.

  Next, the Cu paste used in [Example 1] is used, screen-printed on a magnetic sheet, first to fourth coil patterns and electrode patterns are formed, and via holes are filled with the Cu paste. did.

Next, the magnetic sheets on which the first to fourth coil patterns and the electrode patterns are formed are laminated in a predetermined order, and the upper and lower main surfaces are not formed with the first to fourth coil patterns and the electrode patterns. Sandwiched between body sheets, heated to 60 ° C., pressurized and pressed for 60 seconds at a pressure of 100 MPa, cut into a predetermined size, and a laminated molded body was produced. Next, the same method as in Example 1 A degreasing and firing process was performed according to the procedure to prepare a component body, and external electrodes were formed on both end faces of the component body.

  Thereafter, electrolytic plating was performed on the surface of the external electrode to sequentially form a Ni film and a Sn film, thereby preparing common mode choke coils of sample numbers 111 and 112. The outer shape of the produced sample was 1.2 mm in length, 1.0 mm in width, and 0.5 mm in height.

  Next, for 10 samples of sample numbers 111 and 112, when a DC voltage was applied between the external electrodes, that is, the first and second coil conductors, and the leakage current became 0.1 mA while gradually increasing the voltage. Voltage, that is, leakage voltage was obtained.

  Table 6 shows the average value of the measurement results of 10 samples for each sample.

  As apparent from Table 6, since the magnetic sheet of Sample No. 1 is used for Sample No. 111, the magnetic sheet contains no glass component and the specific resistance logρ is 6. 4 is low. For this reason, when a DC voltage of 10 V was applied, the leakage current exceeded 0.1 mA, and it was found that the insulation performance was inferior.

  On the other hand, it was found that the sample No. 112 had a good insulation performance, even when a DC voltage of 50 V was applied, the leakage current did not exceed 0.1 mA. In other words, sample number 102 uses the magnetic sheet of sample number 9, which is considered to be because the specific resistance logρ inside the element is as high as 7.9.

  Even if the conductive material containing Cu as a main component and the magnetic material are simultaneously fired, a ceramic electronic component such as a common mode choke coil having good insulation and good magnetic properties can be realized.

1 Component Element 3 First Coil Conductor 4 Second Coil Conductor

Claims (5)

The coil conductor includes a first coil conductor and a second coil conductor, and the first coil conductor and the second coil conductor are opposed to each other with a certain distance. A ceramic electronic component embedded in the body ,
The coil conductor is formed of a conductive material mainly composed of Cu,
The component body is formed of a ferrite porcelain composition containing at least Fe, Mn, Ni, and Zn,
The ferrite ceramic composition is 0 to 5 mol% molar content of Cu in terms of CuO, an Fe molar content x mol% when the terms of _Fe 2 _{O 3,} and Mn in the _Mn 2 _{O 3} When the converted molar amount ymol% is expressed by (x, y), (x, y) is A (30,1), B (47,1), C (47,7.5) , D (45, 7.5), E (45, 10), F (35, 10), G (35, 7.5), and H (30, 7.5), and When glass components including at least Si, B, and alkaline earth metal M are converted to Fe ₂ O _3, Mn ₂ O ₃ , NiO, ZnO, and CuO, respectively, Fe, Mn, Ni, Zn, and Cu 1 part by weight or more and 5 parts by weight or less with respect to a total of 100 parts by weight,
The respective contents of Si, B, and alkaline earth metal M are ₂₀ to 55 wt% in terms of SiO ₂ , 10 to 20 wt% in terms of B ₂ O ₃ , and 25 to 60 wt% in terms of MO , respectively. ceramic electronic component, characterized in that it. The alkaline earth metal, Ba, Sr, Ca, and claim 1 Symbol mounting ceramic electronic components characterized in that it contains at least one selected from among Mg. Molar content of the Zn is a ceramic electronic component according to claim 1 or claim 2, wherein the a 6～33Mol% in terms of ZnO. The ceramic electronic component according to any one of claims 1 to 3 , wherein the coil conductor and the component body are fired simultaneously. The ceramic electronic component according to any one of claims 1 to 4, characterized by comprising calcined at Cu-Cu 2 _O average oxygen content of under pressure or atmosphere.

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