JP4434052B2 - Ceramic green sheet, electronic component using the same, and manufacturing method thereof - Google Patents

Description

  The present invention relates to a ceramic green sheet, an electronic component using the same, and a manufacturing method thereof.

  Inductors, capacitors, thermistors, varistors, and the like are known as laminated electronic components in which ceramic layers and conductor layers are alternately laminated. In these multilayer electronic components, the conductor layer is conventionally formed by a printing method such as screen printing, so the thickness of the conductor layer is generally smaller than the thickness of the ceramic layer. there were.

  In recent years, with the miniaturization of electronic devices, further miniaturization is required for electronic components mounted on them. However, in spite of the trend toward miniaturization, electronic components can be used in a variety of environments, and even when a large current flows, they may not be easily damaged. It has been demanded.

  In order to cope with a large current, the thickness of the conductor layer may be increased. In this case, in order to maintain the size of the entire electronic component, the ceramic layer has a thickness corresponding to the increase in the thickness of the conductor layer. Thinning is required. That is, in an electronic component that can handle a large current, the conductor layer is thicker and the ceramic layer is often thinner than in the past.

  Here, in the multilayer electronic component as described above, a conductive paste layer is printed on a ceramic green sheet containing ceramic powder, a binder, or the like, and a plurality of these are stacked and pressed, and then the obtained multilayer body is fired. It is often manufactured by doing.

  However, when an electronic component is manufactured by such a method, if an attempt is made to form a thick conductor layer and a thin ceramic layer as described above, the thick conductive paste layer is strongly applied to the thin ceramic green sheet during pressing. Since it bites in, the ceramic green sheet after pressing is greatly deformed, and thus tends to have a large stress. If it becomes like this, in manufacture of an electronic component, it will become easy to generate | occur | produce a crack and delamination between a conductor layer and a ceramic layer resulting from the stress mentioned above at the time of baking of a laminated body or after baking. For this reason, an electronic component having a thick conductor layer and a thin ceramic layer in order to reduce the size while supporting a large current may cause a short circuit between the conductor layers due to such cracks and delamination. The characteristics were often insufficient.

Under such circumstances, as a method of manufacturing electronic components that can sufficiently suppress the occurrence of cracks and delamination, a desired portion of the ceramic green sheet is irradiated with laser light to form a recess, and a conductor layer is formed in this recess After that, a method of laminating a plurality of obtained ceramic green sheets has been proposed (see Patent Document 1). In this method, since the conductor layer is formed in the concave portion on the ceramic green sheet provided in advance, the occurrence of stress due to the biting of the conductor paste layer during pressing is reduced. Thereby, generation | occurrence | production of the above cracks and delamination can be reduced.
JP-A-7-106175

  However, the method for manufacturing an electronic component according to the above-described prior art performs a step of forming a recess with a laser beam on a ceramic green sheet, so that it takes a long time to manufacture the green sheet, and a facility for irradiating a laser beam is required. For this reason, there has been a manufacturing disadvantage such as an increase in manufacturing costs. Further, in the above method, it is difficult to select a laser beam having an appropriate output due to variations in density and the like depending on the green sheet to be used. For this reason, in this method, it is difficult to accurately form the concave portion corresponding to the thickness of the conductor layer, and there are many cases where it is not possible to obtain an electronic component in which cracks and delamination are sufficiently reduced.

  The present invention has been made in view of such circumstances, and is a ceramic that can easily manufacture an electronic component with less generation of cracks and delamination even when downsizing is achieved while supporting a large current. The purpose is to provide green sheets. Another object of the present invention is to provide a method for producing such a ceramic green sheet, an electronic component using the same, and a method for producing the same.

In order to achieve the above object, the ceramic green sheet of the present invention is a phosphoric acid comprising a ferrite powder, a butyral, acrylic or cellulose binder resin, a solvent, and polyoxyethylene alkyl ether phosphate or an amine salt thereof. A compound having a group, a compound having a sulfonic acid group composed of dodecylbenzenesulfonic acid, dimethylbenzenesulfonic acid or an amine salt thereof, or a compound having a carboxyl group composed of an amine salt of polyester acid or an amine salt of polyetherester acid And an acidic compound having an amine value of 15 or more.

  Since the ceramic green sheet of the present invention contains an acidic compound having an amine value of 15 or more, the ceramic green sheet is more flexible than a conventional ceramic green sheet not containing such an acidic compound. For this reason, the ceramic green sheet of the present invention can be flexibly deformed even when strongly compressed by a press or the like when used for manufacturing an electronic component, and stress is also generated by the biting of the conductive paste layer as described above. hard. Therefore, according to the ceramic green sheet of the present invention, even when the conductor layer is thick and the ceramic layer is thin, the occurrence of cracks and delamination between them can be sufficiently reduced. .

  As described above, the ceramic green sheet of the present invention can be flexible because of the following factors. That is, when the above-described acidic compound is added to a material containing ceramic powder, a binder resin, and a solvent, the ceramic particles constituting the ceramic powder are easily aggregated. For this reason, the ceramic green sheet which consists of this material comes to have many area | regions which do not contain a ceramic particle compared with the thing which does not contain an acidic compound, and a density becomes small in connection with this. As a result, the ceramic green sheet has many areas composed of a flexible binder resin or the like, and the sheet itself becomes flexible.

  The agglomeration of the ceramic particles described above is usually caused by the ceramic particles having a predetermined surface potential being reduced as a result of the surface potential being reduced by the addition of the acidic compound having the predetermined amine value. It is presumed that the interaction due to the Coulomb force between them is stronger than the repulsion of the surface potential. However, the action is not limited to these.

  The ceramic green sheet of the present invention preferably includes a compound having a phosphoric acid group, a sulfonic acid group, or a carboxyl group as an acidic compound. By adding these compounds, the density of the ceramic green sheet is appropriately reduced, and better flexibility can be obtained.

More specifically, the density of the ceramic green sheet is more preferably 2.61 to 3.11 g / cm ³ . The ceramic green sheet having such a density has good flexibility, and as a result, generation of cracks and the like in the electronic component can be further suppressed.

The ceramic green sheet of the present invention comprises a ferrite powder, a butyral-based, acrylic-based or cellulose-based binder resin, a solvent, a compound having a phosphate group comprising a polyoxyethylene alkyl ether phosphate or an amine salt thereof, dodecyl A compound having a sulfonic acid group consisting of benzenesulfonic acid, dimethylbenzenesulfonic acid or an amine salt thereof, or a compound having a carboxyl group consisting of an amine salt of polyester acid or an amine salt of polyetherester acid, has an amine value of 15 It can manufacture suitably with the manufacturing method including the process of mixing with the acidic compound which is the above.

The present invention also includes a ceramic layer and a conductor layer, and the ceramic layer includes ferrite powder, butyral, acrylic or cellulose binder resin, a solvent, and polyoxyethylene alkyl ether phosphate or the same. From a compound having a phosphate group consisting of an amine salt, a compound having a sulfonic acid group consisting of dodecylbenzenesulfonic acid, dimethylbenzenesulfonic acid or an amine salt thereof, or an amine salt of polyester acid or an amine salt of polyetherester acid amine value consists compound having made carboxyl groups to provide an electronic component is made of a sintered product of a ceramic green sheet containing an acidic compound is 15 or more. Since such an electronic component includes a ceramic layer made of a fired product of the ceramic green sheet, cracks and the like between the ceramic layer and the conductor layer are extremely small.

An electronic component having the above structure includes a conductive material layer containing a conductive material, a ferrite powder, a butyral, acrylic or cellulose binder resin, a solvent, and a polyoxyethylene alkyl ether phosphate or an amine salt thereof. A compound having an acid group, a compound having a sulfonic acid group composed of dodecylbenzenesulfonic acid, dimethylbenzenesulfonic acid or an amine salt thereof, or a carboxyl group composed of an amine salt of polyester acid or an amine salt of polyetherester acid A step of laminating a ceramic green sheet comprising an acidic compound having an amine value of 15 or more, a step of obtaining a laminate, a step of firing the laminate, and a step of providing external electrodes on the laminate after firing. It can be suitably manufactured by a manufacturing method including

  According to the present invention, in order to reduce the size while accommodating a large current, even when an electronic component having a thicker conductor layer and a thinner ceramic layer is manufactured than in the past, the occurrence of cracks and delamination is small. The ceramic green sheet which can manufacture an electronic component simply can be provided. Moreover, according to this invention, the manufacturing method of this ceramic green sheet, the electronic component using this ceramic green sheet, and its manufacturing method can be provided.

  Preferred embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same element through all figures, and the overlapping description is abbreviate | omitted.

  First, the configuration of a multilayer inductor that is an example of a multilayer electronic component will be described with reference to FIGS. FIG. 1 is a perspective view showing a multilayer inductor according to the present embodiment. FIG. 2 is a diagram for explaining a cross-sectional configuration of the multilayer inductor according to the present embodiment. FIG. 3 is an exploded perspective view of the multilayer body included in the multilayer inductor according to the present embodiment. This multilayer inductor 1 is obtained by applying a ceramic green sheet according to a preferred embodiment.

  As shown in FIG. 1, the multilayer inductor 1 includes a substantially rectangular parallelepiped inductor element 10 and a pair of terminal electrodes (external electrodes) 11 and 12 formed on both side surfaces of the inductor element 10 in the longitudinal direction. With. The bottom surface of the inductor body 10 is a surface facing the external substrate when the multilayer inductor 1 is mounted on the external substrate (not shown).

  As shown in FIGS. 2 and 3, the inductor element body 10 is configured by laminating a plurality (12 in this embodiment) of ceramic layers A1 to A12, and a conductor pattern (conductor layer) B1 therein. The coil L which consists of -B10 and derivation | leading-out part B1a, B10a is provided. The actual multilayer inductor 1 is integrated to such an extent that the boundaries between the ceramic layers A1 to A12 cannot be visually recognized. As will be described later, the ceramic layers A1 to A12 are formed by firing a ceramic green sheet and function as an insulator.

  The ceramic layers A1 to A12 are insulators having electrical insulation, and are made of a fired product of ceramic green sheets according to a preferred embodiment. The ceramic layers A1 to A12 are mainly composed of ferrite (for example, Ni—Cu—Zn based ferrite, Ni—Cu—Zn—Mg based ferrite, Cu—Zn based ferrite, or Ni—Cu based ferrite). The ceramic layers A1 to A12 have a thickness of about 60 μm, for example.

  The conductor pattern B1 corresponds to approximately 5/8 turns of the coil L, and is formed in a substantially C shape on the ceramic layer A2. A lead-out portion B1a is integrally formed at one end of the conductor pattern B1. The lead-out part B1a of the conductor pattern B1 is drawn out to the edge of the ceramic layer A2, and its end is exposed on the end face of the ceramic layer A2. For this reason, the lead-out part B1a is electrically connected to the terminal electrode 11. The other end of the conductor pattern B1 is electrically connected to a through-hole electrode C1 formed through the ceramic layer A2 in the thickness direction. For this reason, the conductor pattern B1 is electrically connected to one end of the corresponding conductor pattern B2 through the through-hole electrode C1 in a stacked state.

  The conductor patterns B2 to B9 correspond to approximately 3/4 turns of the coil L, and the conductor patterns B2, B4, B6, and B8 are substantially U-shaped on the ceramic layers A3, A5, A7, and A9, respectively. The conductor patterns B3, B5, B7, and B9 are formed in a substantially C shape on the ceramic layers A4, A6, A8, and A10. One end of each conductor pattern B2 to B9 includes a region electrically connected to each through-hole electrode C1 to C8 in a stacked state. The other ends of the conductor patterns B2 to B9 are electrically connected to the through-hole electrodes C2 to C9 formed through the ceramic layers A3 to A10 in the thickness direction, respectively. For this reason, each conductor pattern B2-B9 is electrically connected with the end of each corresponding conductor pattern B3-B10 via each through-hole electrode C2-C9 in the laminated state.

  The conductor pattern B10 corresponds to approximately 7/8 turns of the coil L, and is formed in a substantially U shape on the ceramic layer A11. One end of the conductor pattern B10 includes a region electrically connected to each through-hole electrode C9 in a stacked state. A lead-out portion B10a is integrally formed at the other end of the conductor pattern B10. The lead-out part B10a of the conductor pattern B10 is drawn out to the edge of the ceramic layer A11, and its end is exposed on the end surface of the ceramic layer A11. For this reason, the lead-out portion B10a is electrically connected to the terminal electrode 12.

  Here, the thickness a of the conductor pattern in the inductor body 10 (thickness in the stacking direction, see FIG. 2) and the thickness b of the ceramic layers A1 to A12 (thickness in the stacking direction, see FIG. 2) are a / It is preferable that b ≧ 1 be satisfied. That is, the thickness of the conductor patterns B1 to B10 is preferably equal to or greater than the thickness of the ceramic layers A1 to A12.

  By doing so, the multilayer inductor 1 has a coil L having a large cross-sectional area, and can sufficiently cope with a large current. Further, since the distance between the adjacent conductor patterns becomes relatively small, the magnetic coupling between the turns in the coil L becomes strong, thereby increasing the inductor value. As a result, the number of turns of the coil L required for obtaining a desired inductance value can be reduced, and the multilayer inductor 1 can be easily reduced in size. From the viewpoint of obtaining these effects better, a / b is preferably 1.5 or more.

  As described above, the ceramic layers A1 to A12 are laminated, and the conductor patterns B1 to B10 are electrically connected to each other through the through hole electrodes C1 to C9, so that the number of turns is 7.5 turns. That is, the coil L is configured. Here, each of the conductor patterns B1 to B10 and the lead-out portions B1a and B10a is formed by screen printing a conductor paste mainly composed of silver or nickel.

  Next, a method for manufacturing a multilayer inductor will be described with reference to FIGS. FIG. 4 is a diagram for explaining a method for manufacturing a multilayer inductor according to a preferred embodiment, and is a diagram illustrating a multilayer structure including a ceramic green sheet and a conductive paste layer (conductive material layer). Here, for convenience of explanation, a method of manufacturing a multilayer inductor composed of four ceramic layers and a three-layer conductor pattern provided therebetween will be described.

  First, ceramic green sheets G1 to G4 for forming a ceramic layer are prepared (see FIG. 4A). These ceramic green sheets G1 to G4 constitute a ceramic layer of the multilayer inductor by firing.

  Here, components constituting the ceramic green sheets G1 to G4 will be described. The ceramic green sheets G1 to G4 contain ceramic powder, a binder resin, a solvent, and an acidic compound having an amine value of 15 or more.

  Examples of the ceramic powder include a powder made of the above-described ferrite (for example, Ni—Cu—Zn based ferrite, Ni—Cu—Zn—Mg based ferrite, Cu—Zn based ferrite, or Ni—Cu based ferrite). . The average particle size of the ceramic powder is preferably 0.06 to 0.6 [mu] m, and more preferably 0.1 to 0.6 [mu] m.

  The binder resin can be used without particular limitation as long as it is usually a resin material mixed with a ceramic material, and examples thereof include butyral, acrylic, and cellulose binder resins. Moreover, as a solvent, what has the property which can melt | dissolve or disperse | distribute a binder resin favorably is preferable, for example, aromatic hydrocarbons, alcohols, ketones, esters, or these mixed solvents are mentioned.

The “acidic compound having an amine value of 15 or more” is a compound having a functional group in the molecule such that the amine value is 15 or more. Here, the amine value and is defined as the amount of hydrochloric acid in an amount and equivalent of KOH required when an attempt is made to neutralize any government functional group that is part of the said acidic compounds 1 g (mg). Examples of such acidic compounds include amine salts of compounds having a phosphoric acid group, a sulfonic acid group, or a carboxyl group.

  As a compound which has a phosphoric acid group, phosphoric acid polyoxyethylene alkyl ether and its amine salt are mentioned, for example. Specific examples include phosphoric acid polyoxyethylene nonyl ether. Examples of the compound having a sulfonic acid group include dodecylbenzenesulfonic acid, dimethylbenzenesulfonic acid, and amine salts thereof. Furthermore, examples of the compound having a carboxyl group include an amine salt of a polyester acid, an amine salt of a polyether ester acid, and more specifically, an amine salt of a higher fatty acid derivative, an amine salt of a higher aliphatic polycarboxylic acid, Amine salts of specially modified polyester acids are preferred.

  When the ceramic green sheets G1 to G4 contain the above component, particularly an acidic compound having an amine value of 15 or more, the dispersibility of the ceramic powder in the green sheet is reduced, and the ceramic particles constituting the powder However, it will be in the state which is easy to aggregate compared with the past. For this reason, the ceramic green sheets G1 to G4 have a low content of the ceramic powder, and the proportion of the relatively flexible binder resin increases accordingly. As a result, the ceramic green sheets G1 to G4 are more flexible than the conventional ceramic green sheets, and have excellent characteristics for relieving stress caused by pressing or the like when used for manufacturing electronic components and the like.

  From the viewpoint of obtaining such an effect better, the amine value of the acidic compound is preferably 15 or more, and more preferably 19 or more. If the acidic compound has an amine value that is too high, the ceramic powder will agglomerate too much, which may cause partial variations in the thickness and characteristics of the formed ceramic layer. The upper limit is preferably about 58.

Moreover, it is preferable that the ceramic green sheets G1-G4 of this embodiment have a density as shown below as a result of the content ratio of the ceramic powder being reduced as described above. That is, the density of the ceramic green sheet G1~G4 is preferable to be 2.61~3.11g / cm ^3, more preferable to be 2.61~2.83g / cm ^3, 2.61~2.77g / Cm ³ is more preferable. When the density of the ceramic green sheets G1 to G4 is less than 2.61, variations in thickness and characteristics of the obtained ceramic layer may easily occur. On the other hand, when the density exceeds 3.11 g / cm ³ , the flexibility of the ceramic layer becomes insufficient, and it may be difficult to relieve stress generated during the manufacture of electronic components.

  Such ceramic green sheets G1 to G4 are, for example, coated with a ceramic powder, a binder resin, a solvent, and a slurry containing an acidic compound having an amine value of 15 or more on a substrate such as a PET film. You can get it. In addition, after application, the solvent may be volatilized to some extent by heating. The obtained ceramic green sheets G1 to G4 may be used after being peeled off from the substrate, or may be used as they are. When using as it is, after laminating ceramic green sheets G1 to G4 on an arbitrary adherend, the substrate is peeled off.

  After obtaining the ceramic green sheets G1 to G4 in this manner, through holes are respectively formed by laser processing or the like at these predetermined positions, that is, positions where the through hole electrodes as described above are to be formed. Next, conductive paste layers P1 to P3 (conductive material layer, see FIG. 4A) are formed on the ceramic green sheets G1 to G4 by printing a conductive paste containing conductive powder, a binder, and the like. These conductive paste layers P1 to P3 each have a shape that can constitute a part of a coil in the multilayer inductor after being laminated. At this time, the conductive paste is preferably applied so as to fill the through-holes described above. Thereby, in the baking mentioned later, a conductor pattern and a through-hole electrode will be formed simultaneously.

  Thereafter, the ceramic green sheets G1 to G4 are stacked (see FIG. 4A), and then pressure is applied in the stacking direction so that no gap is generated between the ceramic green sheets G1 to G4. (See FIG. 4B). As shown in the figure, in the laminate 20, the conductive paste layers P1 to P3 are in a state of being bitten into the adjacent ceramic green sheets G1 to G4 on both sides. In other words, the ceramic green sheets G1 to G4 have a shape in which the regions in contact with the conductive paste layers P1 to P3 are greatly recessed. However, since the ceramic green sheets G1 to G4 are low in density and flexible as described above, there is little generation of stress even in such a recessed state. Cracks and delaminations are less likely to occur between P1 and P3.

  Next, after the laminated body 20 is cut into chips, firing is performed at a predetermined temperature (for example, about 870 ° C.) to form an inductor body. For example, the length of the inductor body in the longitudinal direction after firing is 2.0 mm, the width is 1.25 mm, and the height is 0.8 mm. By such firing, the ceramic green sheets G1 to G4 become ceramic layers, and the conductive paste layers P1 to P3 become conductor patterns.

  Thereafter, terminal electrodes are formed on the obtained inductor body. Thereby, a multilayer inductor is formed. The terminal electrode is baked at a predetermined temperature (for example, about 700 ° C.) and electroplated after transferring an electrode paste mainly composed of silver, nickel, or copper to both end faces in the longitudinal direction of the inductor body. Can be formed. For this electrode plating, Cu, Ni, Su, or the like can be used.

  As described above, in the method for manufacturing a multilayer inductor according to this embodiment, the ceramic layer is formed from the ceramic green sheets G1 to G4 having low density and being flexible. For this reason, when forming the laminated body 20 by pressing, the ceramic green sheets G1 to G4 can be flexibly deformed in accordance with the shapes of the conductive paste layers P1 to P3. Therefore, in the laminated body 20, the stress produced with the biting of the conductive paste layers P1 to P3 is extremely small.

  Conventionally, when a multilayer inductor is formed by firing a multilayer body, cracks and delamination are likely to occur between them due to the stress of the ceramic green sheet generated by the penetration of the conductive paste layer. On the other hand, in the manufacture of the multilayer inductor of the above embodiment, the generation of such cracks and delamination is greatly suppressed by using the flexible ceramic green sheets G1 to G4 having a small density as described above. It is possible.

  More specifically, even when the conductive paste layers P1 to P3 are formed to be thicker than the ceramic green sheets G1 to G4, the occurrence of such cracks and the like can be sufficiently reduced. Therefore, by using the ceramic green sheets G1 to G4 of the present embodiment, it is possible to easily obtain a multilayer inductor that can cope with a large current and is sufficiently miniaturized.

  As described above, the multilayer electronic component obtained by using the ceramic green sheet according to the preferred embodiment of the present invention and the manufacturing method thereof have been described by taking the multilayer inductor as an example. However, the present invention is not necessarily limited to the above embodiment. However, various modifications are possible without departing from the spirit of the invention.

  First, the ceramic green sheet contains an “acidic compound having an amine value of 15 or more”. In addition to the “amine value”, an “acid value” is used as an index representing the properties of the “acidic compound”. be able to. Here, the “acid value” refers to the amount (mg) of KOH required to neutralize 1 g of the acidic compound. The “acid value” of the acidic compound is preferably 0 to 500, and more preferably 40 to 300.

  The multilayer inductor may have a multilayer structure different from that described above. For example, the ceramic layer may include a nonmagnetic layer made of a nonmagnetic material in addition to the magnetic material layer made of ferrite.

  Furthermore, the present invention is not limited to a multilayer inductor, and can be applied without particular limitation as long as it has a structure in which conductor layers and ceramic layers are alternately stacked. Specifically, a capacitor, a thermistor, a varistor, etc. can be illustrated, for example. Electronic components other than these inductors can be obtained by appropriately selecting the constituent material of the ceramic layer, the shape of the conductor layer, and the like suitable for each electronic component. In any electronic component, a ceramic green sheet containing a ceramic powder, a binder resin, a solvent, and an acidic compound having an amine value of 15 or more (or an acid value of 40 or more) is used as a constituent material of the ceramic layer. As a result, the occurrence of cracks and delamination is extremely small.

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples.
[Manufacture of multilayer inductors]

Example 1
First, 100 parts by mass of Ni-Cu-Zn ferrite powder as ceramic powder, 7 parts by mass of butyral resin as binder resin, 4 parts by mass of plasticizer, and 95 parts by mass of toluene and isobutyl alcohol as solvents are prepared. And a solvent were mixed and dissolved to prepare a resin solution, and then other components were added thereto, and the mixture was put into a ball mill and dispersed for 48 hours. During this dispersion, a slurry containing ceramic powder was prepared by adding an amine salt of a polyester acid having an amine value of 19 as an acidic compound. Next, the obtained slurry was applied on a PET film by a doctor blade method so as to have a thickness of 45 μm to obtain a ceramic green sheet. The obtained ceramic green sheet had a density decreased by 12.1% as compared with that containing no amine salt.

  After a plurality of ceramic green sheets were formed, through holes were formed on the desired ceramic green sheets using a laser. Then, a conductive paste mainly composed of silver was applied on a predetermined ceramic green sheet through a metal mask to form a conductive paste layer having a thickness of about 40 μm and a pattern width of 160 μm. And the laminated body which incorporates the coil-like pattern which consists of an electrically conductive paste layer and a through hole was obtained by laminating | stacking each obtained ceramic green sheet. The number of turns of the obtained coiled pattern was 7.5 turns.

  Thereafter, this laminate was cut so that the finished dimensions were length: 2.0 mm, width: 1.25 mm, height: 0.8 mm (this dimension is expressed as “2012”). Chip. And after baking the obtained chip | tip at about 870 degreeC, after apply | coating the electrically conductive paste which has silver as a main component to the both ends of a baked product, it baked at about 700 degreeC, and also Cu, Ni, and it by electroplating on it. Sn plating was performed to form terminal electrodes. Thus, a multilayer inductor having a configuration similar to that shown in FIGS.

  As a result of analyzing the internal state of the obtained multilayer inductor by DPA, the thickness of the conductor pattern is 21.2 μm, the width of the conductor pattern is 139 μm, and the interlayer distance of this conductor pattern is 16.2 μm. Was confirmed. Further, the inductance of this multilayer inductor was 1.02 μH, and the DC resistance was 0.12Ω. From this, it was found that even when the rated current was 0.5 A, the level was sufficient. These values are average values obtained by forming 100 similar multilayer inductors.

(Examples 2-4, Comparative Examples 1-2)
As an acidic compound, an amine salt of a polyester acid having an amine value of 15 (Example 2), 32 (Example 3), 58 (Example 4), 10 (Comparative Example 1) and 14 (Comparative Example 2) is used. A multilayer inductor was obtained in the same manner as in Example 1 except that. The thickness of the conductor pattern, the thickness of the ceramic layer, and the overall size in each multilayer inductor were made to be substantially the same as those in Example 1.
[Measurement of failure rate of multilayer inductor]

About the laminated inductors of Examples 1 to 4 and Comparative Examples 1 and 2, 1000 samples were produced. Then, all samples were observed, and it was determined whether or not cracks or delamination occurred in the laminated structure of the conductor pattern and the ceramic layer. Then, among 1000 samples corresponding to each example or comparative example, the number of samples where cracks occurred and the number of samples where delamination occurred were counted, and based on this value, corresponding to each example and comparative example The crack generation rate (%) and delamination generation rate (%) (collectively referred to as “failure rate”) of the multilayer inductor were calculated. The obtained results are shown in Table 1 together with the amine value (KOH mg / g) of the acidic compound and the density (g / cm ³ ) of the ceramic green sheet used for the production of each multilayer inductor. In addition, as a density of the ceramic green sheet, a range from a minimum value to a maximum value of values obtained by measuring four samples out of 1,000 samples is shown.

  From Table 1, the laminated inductors of Examples 1 to 4 obtained using ceramic green sheets containing an acidic compound having an amine value of 15 or more are Comparative Examples 1 using an acidic compound having an amine value of less than 15. It was confirmed that the defect rate (occurrence rate of cracks and delamination) was extremely low as compared with the multilayer inductors 1 and 2.

1 is a perspective view showing a multilayer inductor according to an embodiment. It is a figure for demonstrating the cross-sectional structure of the multilayer inductor which concerns on embodiment. 1 is an exploded perspective view of a multilayer body included in a multilayer inductor according to an embodiment. It is a figure for demonstrating the manufacturing method of the multilayer inductor which concerns on embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Multilayer inductor, 10 ... Inductor body, 11, 12 ... Terminal electrode, A1-A12 ... Ceramic layer, B1-B10 ... Conductor pattern, C1-C9 ... Through-hole electrode, G1-G4 ... Ceramic green sheet, P1 ~ P3 ... conductive paste layer.

Claims (5)

Ferrite powder,
Butyral, acrylic or cellulose binder resins;
Solvent,
A compound having a phosphoric acid group comprising polyoxyethylene alkyl ether phosphate or an amine salt thereof, a compound having a sulfonic acid group comprising dodecylbenzenesulfonic acid, dimethylbenzenesulfonic acid or an amine salt thereof, or an amine salt of polyester acid Or an acidic compound consisting of a compound having a carboxyl group consisting of an amine salt of polyetherester acid, and having an amine value of 15 or more;
A plasticizer,
Ceramic green sheet which is characterized in that it consists of. 2. The ceramic green sheet according to claim 1, wherein the density is 2.61 to 3.11 g / cm ³ . Ferrite powder, butyral, acrylic or cellulose binder resin, solvent, phosphoric acid polyoxyethylene alkyl ether or a compound having a phosphate group consisting of its amine salt, dodecylbenzenesulfonic acid, dimethylbenzenesulfonic acid or compounds having a sulfonic acid group consisting of amine salts, or an acidic compound is made from a compound having a carboxyl group consisting of amine salts of amine salt or polyether ester acid polyester acid, amine value 15 or more, plasticizers The manufacturing method of the ceramic green sheet characterized by including the process of mixing only an agent . An electronic component comprising a ceramic layer and a conductor layer,
Wherein the ceramic layer comprises a ferrite powder, a butyral system, compounds having an acrylic or cellulosic binder resin, and a solvent, a phosphate of polyoxyethylene alkyl ether or a phosphoric acid group consisting of amine salts thereof, dodecylbenzenesulfonic acid, A compound having a sulfonic acid group consisting of dimethylbenzenesulfonic acid or an amine salt thereof, or a compound having a carboxyl group consisting of an amine salt of polyester acid or an amine salt of polyetherester acid, and having an amine value of 15 or more. An electronic component comprising a fired product of a ceramic green sheet comprising an acidic compound and a plasticizer . A conductive material layer containing a conductive material, ferrite powder, a butyral resin, acrylic resin or a cellulose-based binder resin, a solvent, a compound having a-phosphate polyoxyethylene alkyl ethers or phosphate groups consisting of amine salts thereof, dodecylbenzenesulfonic A compound having a sulfonic acid group consisting of acid, dimethylbenzenesulfonic acid or an amine salt thereof, or a compound having a carboxyl group consisting of an amine salt of polyester acid or an amine salt of polyetherester acid, and an amine value of 15 or more A step of laminating an acidic compound as well as a ceramic green sheet made of a plasticizer to obtain a laminate,
Firing the laminate;
Providing an external electrode on the laminate after firing; and
Of electronic parts including

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