JP2002043164A - Laminated ceramic electronic component and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic paste, including highly dispersed ceramic powder. SOLUTION: In order to manufacture the ceramic paste, a first dispersion step of dispersing a first mixture including at least ceramic powder and a first organic solvent, a removing step of selectively removing the first organic solvent, and a second dispersion step of dispersing a second mixture made by adding an organic binder to the first mixture, from which the first organic solvent is removed are performed in sequence. The first mixture and/or the second mixture includes the second organic solvent having a higher boiling point than that of the first organic solvent. This ceramic paste is used with advantage, for example, to form a ceramic green layer 5 for absorbing a step on the main surface of a ceramic green sheet 2, so as to substantially eliminate a step due to by the thickness of an internal electrode 1 in a laminated ceramic capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer ceramic electronic component and a method for manufacturing the same.
Multilayer ceramic electronic component having a step absorbing ceramic layer formed with a negative pattern of an internal circuit element film pattern to absorb a step caused by the thickness of an internal circuit element film formed between ceramic layers, and a method of manufacturing the same It is about.

[0002]

2. Description of the Related Art When manufacturing a multilayer ceramic electronic component such as a multilayer ceramic capacitor, a plurality of ceramic green sheets are prepared and these ceramic green sheets are stacked. Depending on the function of the multilayer ceramic electronic component to be obtained, internal circuits such as conductor films and resistor films for forming capacitors, resistors, inductors, varistors, filters, etc., on specific ceramic green sheets An element film is formed.

In recent years, electronic devices such as mobile communication devices have been reduced in size and weight. In such electronic devices, for example, when a multilayer ceramic electronic component is used as a circuit element, such electronic devices have been described. There has been a strong demand for miniaturized and lightweight ceramic electronic components. For example, in the case of a multilayer ceramic capacitor, demands for miniaturization and large capacity are increasing.

When a multilayer ceramic capacitor is to be manufactured, typically, a ceramic slurry is prepared by mixing a dielectric ceramic powder, an organic binder, a plasticizer and an organic solvent, and this ceramic slurry is used as a release agent. Coated with silicone resin, etc.
For example, a ceramic green sheet is produced by applying a doctor blade method or the like on a support such as a polyester film to form a sheet having a thickness of, for example, several μm. Is dried.

[0005] Next, a conductive paste is applied on the main surface of the above-described ceramic green sheet in a plurality of patterns spaced apart from each other by screen printing.
By drying this, an internal electrode as an internal circuit element film is formed on the ceramic green sheet. FIG. 7 is a plan view showing a part of the ceramic green sheet 2 on which the internal electrodes 1 are formed at a plurality of locations as described above.

Next, after the ceramic green sheets 2 are peeled off from the support and cut into a suitable size, a predetermined number of them are stacked as shown in FIG. By stacking a predetermined number of ceramic green sheets on which no internal electrodes are formed, a green laminate 3 is manufactured.

After the green laminate 3 is pressed in the laminating direction, as shown in FIG. 8, it is cut into a size to become a laminate chip 4 for each multilayer ceramic capacitor. After passing through the binder step, it is subjected to a firing step, and finally an external electrode is formed, whereby a multilayer ceramic capacitor is completed.

In such a multilayer ceramic capacitor, in order to satisfy the demand for miniaturization and large capacity, it is necessary to increase the number of stacked ceramic green sheets 2 and internal electrodes 1 and to increase the number of ceramic green sheets 2.
It is necessary to reduce the thickness of the layer.

However, as the above-described multi-layering and thinning progress, the accumulation of the thicknesses of the internal electrode 1 results in the gap between the portion where the internal electrode 1 is located and the portion where it is not, or The difference in thickness between a portion where the electrodes 1 are arranged in a relatively large number in the stacking direction and a portion where the electrodes 1 are not so many becomes more remarkable. For example, as shown in FIG. With regard to, deformation occurs such that one of the main surfaces becomes convex.

If the deformation as shown in FIG. 8 occurs in the laminated chip 4, in a portion where the internal electrodes 1 are not located or in a portion where only a relatively small number of the internal electrodes 1 are arranged in the laminating direction, Since a relatively large strain is caused during the pressing process and the adhesion between the ceramic green sheets 2 is poor, structural defects such as delamination and minute cracks are caused by internal stress caused during firing. Likely to happen.

Further, the deformation of the laminated chip 4 as shown in FIG. 8 results in undesirably deforming the internal electrodes 1,
This may cause a short-circuit failure.

Such inconvenience causes a reduction in the reliability of the multilayer ceramic capacitor.

In order to solve the above-described problem, for example, as shown in FIG. 2, a ceramic green layer 5 for absorbing a step is formed in a region on the ceramic green sheet 2 where the internal electrode 1 is not formed. The step-absorbing ceramic green layer 5 can substantially eliminate the step due to the thickness of the internal electrode 1 on the ceramic green sheet 2 as disclosed in, for example, JP-A-56-94719 and JP-A-3-74820. And JP-A-9-106925.

As described above, by forming the step absorbing ceramic green layer 5, as shown in FIG. 1, when the raw laminate 3a is manufactured, the portion where the internal electrode 1 is located is the same as the portion where the internal electrode 1 is located. And the thickness difference between the portion where the internal electrodes 1 are arranged in a relatively large number in the stacking direction and the portion where the internal electrode 1 is not so much does not substantially occur.
As shown in FIG. 3, undesired deformation as shown in FIG. 8 is less likely to occur in the obtained laminated chip 4a.

As a result, problems such as the above-described structural defects such as delamination and minute cracks and short-circuit failure due to deformation of the internal electrode 1 can be suppressed, and the reliability of the obtained multilayer ceramic capacitor can be improved. Can be.

[0016]

The above-described ceramic green layer 5 for absorbing a step is formed of a ceramic green sheet 2.
And formed by applying a ceramic paste containing a dielectric ceramic powder, an organic binder, a plasticizer and an organic solvent, but having a thickness similar to that of the internal electrode 1, for example, a thickness of 2 μm or less. In order to form the step-absorbing ceramic green layer 5 with high precision by printing or the like so that the ceramic powder has the above-mentioned, the dispersibility of the ceramic powder in the ceramic paste must be excellent.

In connection with this, for example, Japanese Unexamined Patent Publication No. 3-74
No. 820 discloses that in order to obtain a ceramic paste,
Although the dispersing process using this roll is disclosed, it is difficult to obtain the excellent dispersibility as described above by the dispersing process using only three rolls.

On the other hand, in Japanese Patent Application Laid-Open No. 9-106925, a ceramic slurry for the ceramic green sheet 2 is prepared by mixing a dielectric ceramic powder, an organic binder, and a first organic solvent having a low boiling point. This is used for forming the ceramic green sheet 2, and the ceramic slurry is mixed with a second organic solvent having a boiling point higher than the boiling point of the above-mentioned first organic solvent. It is described that a ceramic paste for the step-absorbing ceramic green layer 5 is prepared by replacing the first organic solvent having a boiling point with a second organic solvent having a high boiling point.

Therefore, in the ceramic paste obtained as described above, at least two mixing steps are performed, so that the dispersibility of the ceramic powder is improved to some extent. ,
Since it is carried out in a state containing an organic binder, the viscosity of the slurry or paste at the time of mixing is high, and for example, in a dispersing machine using a medium such as a ball mill, the dispersibility of the ceramic powder is improved. Has limitations.

As described above, the ceramic paste used for forming an extremely thin ceramic layer such as the step absorbing ceramic green layer 5 having a thickness equal to the thickness of the internal electrode 1 is excellent with respect to the ceramic powder contained therein. Dispersibility is required, and the requirement for such excellent dispersibility becomes more severe as the thickness of the internal electrode 1 decreases.

Further, the step absorbing ceramic green layer 5
Even if the dispersibility of the ceramic powder is poor, the ceramic green sheet 2
However, when the thickness of the ceramic green sheet 2 is reduced, the effect of covering the dispersibility by such a ceramic green sheet 2 can hardly be expected.

From the above, as the size and capacity of the multilayer ceramic capacitor increase, the ceramic powder in the step absorbing ceramic green layer 5 needs to have higher dispersibility.

In order to increase the dispersion efficiency of the ceramic powder in the mixing step, it is conceivable to lower the viscosity of the ceramic paste. In order to lower the viscosity, the amount of the above-mentioned low boiling organic solvent to be added is reduced. If it increases, another problem that a long time is required to remove the organic solvent having a low boiling point after the dispersion treatment is encountered.

Although the above description has been made with reference to the multilayer ceramic capacitor, the same problem is encountered in other multilayer ceramic electronic components such as a multilayer ceramic inductor other than the multilayer ceramic capacitor.

It is an object of the present invention to provide a method for manufacturing a multilayer ceramic electronic component and a multilayer ceramic electronic component obtained by the manufacturing method, which can solve the above-mentioned problems. .

[0026]

The present invention is first directed to a method for manufacturing a multilayer ceramic electronic component. In this manufacturing method, basically, the following steps are performed.

First, a ceramic slurry, a conductive paste and a ceramic paste are prepared.

Next, the ceramic green sheet obtained by molding the ceramic slurry and the conductive paste are partially applied to the main surface of the ceramic green sheet so as to provide a step due to the thickness thereof. Formed on the main surface of the ceramic green sheet and applying a ceramic paste to a region where the internal circuit element film is not formed so as to substantially eliminate a step due to the thickness of the internal circuit element film. A plurality of composite structures including the step-absorbing ceramic green layer are produced.

Next, a green laminate is produced by stacking the plurality of composite structures.

Then, the green laminate is fired.

In a method for manufacturing a multilayer ceramic electronic component having such basic steps,
The method is characterized by a step of preparing a ceramic paste for forming a step absorption ceramic green layer, that is, a method of producing a ceramic paste.

In the present invention, in order to produce a ceramic paste, a primary dispersion step of subjecting a primary mixture containing at least a ceramic powder and a first organic solvent to a dispersion treatment, and, after the primary dispersion step, from the primary mixture. A removing step of selectively removing the first organic solvent by heating; and, after the removing step, a secondary dispersion in which a secondary mixture obtained by adding an organic binder to the primary mixture from which the first organic solvent has been removed is subjected to dispersion treatment. The step and the step of including a second organic solvent having a higher boiling point than the first organic solvent in the primary mixture and / or the secondary mixture are performed.

It should be noted here that the organic binder is added at the stage of the secondary dispersion process. Further, the present invention is characterized in that a first organic solvent and a second organic solvent having a higher boiling point than the first organic solvent are used. The second organic solvent may be added at the stage of the primary dispersion step, added at the stage of the secondary dispersion step, or added at the stage of the primary dispersion step, and further added to the secondary dispersion step. May be added at the stage.

In the case where the second organic solvent is added in the secondary dispersion step, the organic binder is preferably added in a state of being dissolved in the second organic solvent in advance. More preferably, the organic binder previously dissolved in the second organic solvent is added after being filtered.

On the other hand, when the primary mixture to be dispersed in the primary dispersion step further contains a second organic solvent, in the removal step, the second organic solvent is left as it is.
The first organic solvent is removed from the primary mixture.

In the above case, the boiling point of the first organic solvent and the second organic solvent
Is preferably 50 ° C. or more.

In the present invention, the step of preparing the ceramic paste preferably further includes a step of filtering the primary mixture after the primary dispersion step and before the removal step.

In the present invention, the ceramic slurry used for forming the ceramic green sheet is a ceramic powder having substantially the same composition as the ceramic powder contained in the ceramic paste for forming the step absorbing ceramic green layer. It is preferred to include.

In a specific embodiment of the present invention, the ceramic powder contained in each of the ceramic slurry and the ceramic paste is a dielectric ceramic powder. In this case, when the internal circuit element films are the internal electrodes arranged so as to form a capacitance therebetween, a multilayer ceramic capacitor can be manufactured.

In another specific embodiment of the present invention, the ceramic powder contained in each of the ceramic slurry and the ceramic paste is a magnetic ceramic powder. In this case, the internal circuit element film is
When the coil conductor film extends in a coil shape, a multilayer ceramic inductor can be manufactured.

The present invention is also directed to a multilayer ceramic electronic component obtained by the above-described manufacturing method.

[0042]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described.
A method for manufacturing a multilayer ceramic capacitor will be described.
The method for manufacturing the multilayer ceramic capacitor according to this embodiment can be described with reference to FIGS. 1 to 3 described above.

In carrying out this embodiment, a ceramic slurry for the ceramic green sheet 2, a conductive paste for the internal electrode 1, and a ceramic paste for the step-absorbing ceramic green layer 5 are prepared.

The above-mentioned ceramic slurry is prepared by mixing a dielectric ceramic powder, an organic binder, a plasticizer, and an organic solvent having a relatively low boiling point. In order to obtain the ceramic green sheet 2 from this ceramic slurry, the ceramic slurry is formed by a doctor blade method or the like on a support (not shown) such as a polyester film coated with a silicone resin or the like as a release agent. And then dried. Each thickness of the ceramic green sheet 2 is, for example, several μm after drying.

The ceramic green sheet 2 as described above
Of the internal electrodes 1 on the main surface of the
Is formed, for example, with a thickness of about 1 μm after drying. The internal electrode 1 is formed, for example, by applying a conductive paste by screen printing or the like and drying the conductive paste. Each of the internal electrodes 1 has a predetermined thickness. Therefore, a step is generated on the ceramic green sheet 2 due to the thickness.

Next, in order to substantially eliminate the step due to the thickness of the internal electrode 1, a step-absorbing ceramic is provided on the main surface of the ceramic green sheet 2 where the internal electrode 1 is not formed. A green layer 5 is formed. The step absorbing ceramic green layer 5 includes the internal electrode 1.
Is formed by applying the above-mentioned ceramic paste by screen printing or the like with the negative pattern described above, and then dried. The ceramic paste used here is a feature of the present invention,
The details will be described later.

In the above description, the step absorbing ceramic green layer 5 was formed after the internal electrode 1 was formed.
Conversely, the internal electrode 1 may be formed after the step absorption ceramic green layer 5 is formed.

As described above, the composite structure 6 as shown in FIG. 2 in which the internal electrode 1 and the step absorbing ceramic green layer 5 are formed on the ceramic green sheet 2,
After the composite structure 6 is peeled off from the support, a plurality of these composite structures 6 are cut into an appropriate size, a predetermined number of the composite structures 6 are stacked, and an internal electrode and a step-absorbing ceramic green layer are formed above and below the composite structure 6. By stacking the ceramic green sheets that have not been formed, a green laminate 3a as partially shown in FIG. 1 is produced.

After the green laminate 3a is pressed in the laminating direction, as shown in FIG. 3, the green laminate 3a is cut into a size to become a laminate chip 4a for each multilayer ceramic capacitor. After passing through the binder step, it is subjected to a firing step, and finally an external electrode is formed, whereby a multilayer capacitor is completed.

As described above, by forming the step absorption ceramic green layer 5, as shown in FIG. 1, a portion where the internal electrode 1 is located and a portion where the internal electrode 1 is not located in the green laminate 3a. 3 or between the portion where the internal electrodes 1 are arranged in a relatively large number in the stacking direction and the portion where the internal electrodes 1 are not so formed, substantially no difference occurs, and as shown in FIG. And undesired deformation hardly occurs. As a result, in the obtained multilayer ceramic capacitor, problems such as structural defects such as delamination and minute cracks and short-circuit failure can be suppressed.

The present invention is characterized by a method of producing a ceramic paste for forming the step absorbing ceramic green layer 5, and by adopting this characteristic production method, the dispersion of the ceramic powder contained in the ceramic paste is achieved. Can be enhanced.

That is, in the present invention, at least the ceramic powder and the first
A first dispersion step of dispersing a primary mixture containing an organic solvent of the formula (I) and a removal step of selectively removing the first organic solvent from the primary mixture by heating after the primary dispersion step. Is done.

As described above, in the primary dispersion step, since the organic binder has not been added yet, the dispersion treatment can be performed under a low viscosity, and therefore, it is easy to enhance the dispersibility of the ceramic powder. In the primary dispersion step, the air adsorbed on the surface of the ceramic powder is replaced by the first organic solvent, and the ceramic powder can be sufficiently wetted with the first organic solvent. Can be sufficiently disintegrated.

Next, after the above-described removal step, a secondary dispersion step of performing a dispersion treatment of a secondary mixture obtained by adding an organic binder to the primary mixture from which the first organic solvent has been removed is performed. In addition, in order to manufacture the ceramic paste, a second organic solvent having a higher boiling point than the first organic solvent is used in addition to the above-described first organic solvent. This second organic solvent may be added at the stage of the primary dispersion step, added at the stage of the secondary dispersion step, or added at the stage of the primary dispersion step, Additional inputs may be made at the stage.

In any case, in the secondary dispersion step, the second dispersion step is performed.
Is contained in the secondary mixture, and by performing dispersion treatment in this state, it is possible to keep the viscosity of the secondary mixture relatively low even in the stage of the secondary dispersion step. In addition, the dispersion efficiency can be kept relatively high, and the solubility of the organic binder added in the secondary dispersion step as described above can be increased. Therefore, as described above, while maintaining high dispersibility of the ceramic powder obtained in the primary dispersion step,
Organic binder can be mixed sufficiently and uniformly,
Further, a further pulverizing effect of the ceramic powder can be expected.

The ceramic paste obtained as described above contains substantially only the second organic solvent as the organic solvent even though the first organic solvent may slightly remain. Since the second organic solvent has a higher boiling point than the first organic solvent, the drying speed of the ceramic paste can be suppressed to a predetermined value or less, and for example, screen printing can be applied without any problem.

In the primary dispersion step and the secondary dispersion step carried out in the present invention, the dispersion treatment can be carried out by applying a usual dispersion processor using a medium such as a ball mill.

In the present invention, there are various types of organic solvents used as the first organic solvent or the second organic solvent, and in consideration of the boiling point of such an organic solvent, the first organic solvent is used as the first organic solvent. What is used and what is used as the second organic solvent may be selected.

Examples of such organic solvents include ketones such as methyl ethyl ketone, methyl isobutyl ketone and acetone, hydrocarbons such as toluene, benzene, xylene and normal hexane, methanol, ethanol, isopropanol, butanol and amyl alcohol. Alcohols, ethyl acetate, butyl acetate, esters such as isobutyl acetate, diisopropyl ketone, ethyl cellosolve, butyl cellosolve, cellosolve acetate, methyl cellosolve acetate, butyl carbitol, cyclohexanol, pine oil, dihydroterpineol, Ketones such as isophorone, terpineol, propylene glycol, dimethyl phthalate, esters, hydrocarbons, alcohols, chlorinated hydrocarbons such as methylene chloride,
And mixtures thereof.

The boiling points of some of the organic solvents mentioned above are shown in parentheses, and methyl ethyl ketone (79.6 ° C.), methyl isobutyl ketone (118.0 ° C.), acetone (56.1 ° C.) ° C), toluene (111.0 ° C), benzene (79.6 ° C), methanol (64.5 ° C), ethanol (78.5 ° C), isopropanol (82.5 ° C), ethyl acetate (77.1 ° C).
° C), isobutyl acetate (118.3 ° C), diisopropyl ketone (143.5 ° C), methyl cellosolve acetate (143 ° C), cellosolve acetate (156.2)
C), butyl cellosolve (170.6 C), cyclohexanol (160 C), pine oil (195-225).
° C), dihydroterpineol (210 ° C), isophorone (215.2 ° C), terpineol (219.0 ° C).
° C), propylene glycol (231.8 ° C), and dimethyl phthalate (282.4 ° C). The first and second organic solvents may be selected based on such boiling points. .

When the second organic solvent having a high boiling point is added together with the first organic solvent at the stage of the primary dispersion step, the difference between the boiling point of the first organic solvent and the boiling point of the second organic solvent is determined. The difference is preferably 50 ° C. or more. This is to make it easier to selectively remove only the first organic solvent by a heat treatment in the removing step.

The above-mentioned second organic solvent having a high boiling point preferably has a boiling point of 150 ° C. or more, and has a boiling point of about 200 to 250 ° C. in consideration of screen printability. Is more preferred. If the temperature is lower than 150 ° C., the ceramic paste is easy to dry, so that the clogging of the mesh of the printing pattern is likely to occur,
On the other hand, if it exceeds 250 ° C., the printed coating film is difficult to dry,
Therefore, it takes a long time for drying.

The organic binder used in the ceramic paste is preferably one that dissolves in an organic solvent at room temperature. Examples of such organic binders include polyacetals such as polyvinyl butyral and polybutyl butyral, modified celluloses such as poly (meth) acrylates, ethyl cellulose, alkyds, vinylidenes, polyethers, and epoxy resins. , Urethane resins, polyamide resins, polyimide resins, polyamide imide resins, polyester resins, polysulfone resins, liquid crystal polymers, polyimidazole resins, polyoxazoline resins, and the like.

The polyvinyl butyral exemplified above as the organic binder is obtained by condensation of polyvinyl alcohol and butyraldehyde, and is a low polymer product having an acetyl group of 6 mol% or less and a butyral group of 62 to 82 mol%. , Medium polymerization products and high polymerization products. The polyvinyl butyral used as the organic binder in the ceramic paste according to the present invention is preferably a medium polymerized product having a butyral group of about 65 mol% from the balance between the dissolution viscosity in an organic solvent and the toughness of the dried coating film.

The amount of the organic binder to be added is selected from 1 to 20% by weight, preferably from 3 to 10% by weight, based on the ceramic powder.

In the above-described primary dispersion step, the primary mixture preferably contains an organic dispersant. That is, in the primary mixture, the first organic solvent or the first and second
If the organic dispersant is added in a state diluted with the organic solvent, the dispersibility of the ceramic powder is further improved.

The organic dispersant described above is not particularly limited, but from the viewpoint of dispersibility, the molecular weight is preferably 10,000 or less. Anionic, cationic, or nonionic may be used, but polyacrylic acid or its ammonium salt,
Polyacrylate copolymers, polyethylene oxide, polyoxyethylene alkyl amyl ether, fatty acid diethanolamide, polyethylene imine, copolymers of polyoxypropylene monoallyl monobutyl ether and maleic anhydride (and styrene) are preferred.

The amount of the organic dispersant added is 0.1-5% by weight, preferably 0.5-2.
0% by weight.

It is preferable that a step of filtering the primary mixture with a filter is further performed after the primary dispersion step and before the removal step. This makes it possible to remove foreign substances, agglomerates of ceramic powder, and the like, which may be mixed in the ceramic paste, and to reliably obtain a ceramic paste having higher dispersibility.
In addition, air having a small diameter such as adhering to the ceramic powder is broken or removed by filtration, so that pinholes occur in the ceramic layer provided after firing of the ceramic green layer 5 for absorbing a step made of ceramic paste. Can also be expected to have the effect of reducing

It is preferable that an organic vehicle is prepared by previously dissolving an organic binder in a second organic solvent, and this organic vehicle is added to obtain a secondary mixture. Thereby, the undissolved matter of the organic binder that can be mixed in the secondary mixture can be reduced. In this case, if an organic vehicle is filtered through a filter and then added to obtain a secondary mixture, the undissolved matter of the organic binder can be further reduced.

Further, the filtration in the above two embodiments is as follows.
Each of these may be repeated a plurality of times, or the two forms of filtration may be combined. As described above, by repeating the filtration a plurality of times or by combining the two forms of filtration, the effect of the filtration can be further enhanced.

In the above-mentioned filtration step, a filter made of stainless steel or a filter made of a plastic such as polypropylene or a fluororesin is used. In order to increase the filtration speed, the filter is forced by a compressed gas such as air or nitrogen gas. A method of extruding or suctioning under reduced pressure may be adopted.

It is preferable that the ceramic powder contained in the ceramic paste has substantially the same composition as the ceramic powder contained in the ceramic slurry used for forming the ceramic green sheet 2. This is because the sinterability between the step absorbing ceramic green layer 5 and the ceramic green sheet 2 is matched.

Note that having substantially the same composition as described above means that the main components are the same. For example,
Even if minor components such as trace addition metal oxide and glass are different,
It can be said that they have substantially the same composition. Also,
If the ceramic powder contained in the ceramic green sheet 2 has a temperature characteristic of the capacitance that satisfies the B characteristic stipulated by the JIS standard and the X7R characteristic stipulated by the EIA standard, the step-absorbing ceramic green layer 5 is used. The ceramic powder contained in the ceramic paste may have different sub-components as long as they have the same main component and satisfy the B characteristics and the X7R characteristics.

FIG. 4 is a view for explaining a method of manufacturing a multilayer ceramic inductor according to another embodiment of the present invention. FIG. 5 is a perspective view showing the appearance of the multilayer ceramic inductor manufactured by this method. FIG. 2 is an exploded perspective view showing elements constituting a raw laminate 13 prepared for obtaining a laminate chip 12 provided in a ceramic inductor 11.

The green laminate 13 includes a plurality of ceramic green sheets 14, 15, 16, 17,.
9 and these ceramic green sheets 14 to 19
Are obtained by laminating.

The ceramic green sheets 14 to 19 are
It is obtained by shaping a ceramic slurry containing a magnetic ceramic powder by a doctor blade method or the like and drying. Each thickness of the ceramic green sheets 14 to 19 is, for example, 10 to 30 μm after drying.

Among the ceramic green sheets 14 to 19, the ceramic green sheets 15 to 1 positioned at the middle position
8, a coil conductor film extending in a coil shape and a step absorbing ceramic green layer are formed as described in detail below.

First, the coil conductor film 20 is formed on the ceramic green sheet 15. Coil conductor film 20
Is formed such that its first end reaches the edge of the ceramic green sheet 15. A via-hole conductor 21 is formed at the second end of the coil conductor film 20.

To form such a coil conductor film 20 and via-hole conductor 21, for example, a through hole for via-hole conductor 21 is formed in ceramic green sheet 15 by a method such as laser or punching. And a conductive paste that becomes the via-hole conductor 21 is applied by screen printing or the like,
Drying is performed.

Further, in order to substantially eliminate the step due to the thickness of the coil conductor film 20, a region on the main surface of the ceramic green sheet 15 where the coil conductor film 20 is not formed is provided with a step absorption layer. A ceramic green layer 22 is formed. Ceramic green layer for step absorption 2
2 is formed by applying the ceramic paste containing the magnetic ceramic powder, which is a feature of the present invention, by screen printing or the like, and drying the paste.

Next, on the ceramic green sheet 16, the coil conductor film 23, the via hole conductor 24 and the step absorbing ceramic green layer 25 are formed by the same method as described above. First of the coil conductor film 23
Is connected to the second end of the coil conductor film 20 via the via-hole conductor 21 described above. The via-hole conductor 24 is formed at the second end of the coil conductor film 23.

Next, on the ceramic green sheet 17, a coil conductor film 26, a via hole conductor 27 and a step difference absorbing ceramic green layer 28 are similarly formed. The first end of the coil conductor film 26 is connected to the second end of the coil conductor film 23 via the via-hole conductor 24 described above. The via-hole conductor 27 is formed of the coil conductor film 2.
6 formed at the second end.

The above-mentioned lamination of the ceramic green sheets 16 and 17 is repeated a plurality of times as necessary.

Next, a coil conductor film 29 and a step-absorbing ceramic green layer 30 are formed on the ceramic green sheet 18. The first end of the coil conductor film 29 is connected to the second end of the coil conductor film 26 via the via-hole conductor 27 described above. Coil conductor film 29
Is formed such that its second end reaches the edge of the ceramic green sheet 18.

The above-described coil conductor films 20, 23,
The thickness of each of 26 and 29 is, for example, about 30 μm after drying.

The ceramic green sheet 14 as described above
In the raw laminated body 13 obtained by laminating a plurality of composite structures each including-to 19, a plurality of coil conductor films 20, 23, 26 and 29 each extending in a coil shape are formed in the via-hole conductors 21, 24 and 27. , A plurality of turns of the coil conductor are formed as a whole.

By firing the green laminate 13, a laminate chip 12 for the multilayer ceramic inductor 11 shown in FIG. 5 is obtained. The raw laminate 13
Is shown in FIG. 4 as one for obtaining one laminated chip 12, but it is produced for obtaining a plurality of laminated chips, and by cutting this, a plurality of laminated chips are obtained. You may make it take out a chip | tip.

Next, as shown in FIG. 5, the opposite ends of the laminated chip 12 are provided with the above-described coil conductor film 2.
0, and the external electrodes 30 and 31 are formed to be connected to the first end of the coil conductor film 29 and the second end of the coil conductor film 29, respectively.
1 is completed.

In the multilayer ceramic capacitor described with reference to FIGS. 1 to 3 or the multilayer ceramic inductor 11 described with reference to FIGS. 4 and 5, the ceramic green sheet 2 or 14 to 19 or the ceramic green layer for absorbing a step is provided. Examples of the ceramic powder contained in 5 or 22, 25, 28, and 30 include alumina, zirconia, magnesia, titanium oxide, and the like.
Oxide ceramic powders such as barium titanate, lead zirconate titanate, and ferrite-manganese, silicon carbide,
Non-oxide ceramic powders such as silicon nitride and sialon are exemplified. The average particle size of the powder is preferably 5
Spherical or pulverized particles having a size of 1 μm or less, more preferably 1 μm, are used.

When barium titanate having an alkali metal oxide content of 0.1% by weight or less as an impurity is used as a ceramic powder, the following metal oxide is added as a trace component to the ceramic powder. An article or a glass component may be contained.

The metal oxides include terbium oxide, dysprosium oxide, holmium oxide, erbium oxide,
Examples include ytterbium oxide, manganese oxide, cobalt oxide, nickel oxide, and magnesium oxide.

The glass component is Li_Two− (S
iTi) O_Two-MO (where MO is Al_TwoO_ThreeOr
ZrO_Two), SiO_Two-TiO_Two-MO (however, MO
Is BaO, CaO, SrO, MgO, ZnO or Mn
O), Li_TwoOB_TwoO_Three-(SiTi) O_Two+ MO
(However, MO is Al_TwoO_ThreeOr ZrO_Two), B_TwoO
_Three-Al_TwoO_Three-MO (where MO is BaO, Ca
O, SrO or MgO), or SiO_TwoEtc.

Further, in the multilayer ceramic capacitor described with reference to FIGS. 1 to 3 or the multilayer ceramic inductor 11 described with reference to FIGS.
As the conductive paste used for forming the internal electrodes 1 or the coil conductor films 20, 23, 26 and 29 and the via hole conductors 21, 24 and 27, for example, the following can be used.

The conductive paste used in the multilayer ceramic capacitor has an average particle size of 0.02 μm.
３3 μm, preferably 0.05-0.5 μm,
Ag / Pd is 60% by weight / 40% by weight to 10% by weight / 9
0% by weight of a conductive powder made of an alloy, a nickel metal powder or a copper metal powder, and the like, 100 parts by weight of this powder and 2 to 20 parts by weight of an organic binder (preferably 5 to 1 part by weight).
0 parts by weight) and Ag, Au, Pt,
About 0.1 to 3 parts by weight (preferably 0.5 to 1 part by weight) of a metal resinate such as Ti, Si, Ni or Cu in terms of metal, and about 35 parts by weight of an organic solvent are rolled with three rolls. After kneading, a conductive paste obtained by further adding the same or another organic solvent and adjusting the viscosity can be used.

The conductive paste used in the multilayer ceramic inductor 11 includes a conductive powder made of an alloy or Ag containing 80% by weight / 20% by weight / 100% by weight / 0% by weight of Ag / Pd. The same organic binder, sintering inhibitor, and organic solvent as in the case of the conductive paste for a multilayer ceramic capacitor described above were kneaded with three rolls in the same ratio with respect to 100 parts by weight, and then the same or different. The conductive paste obtained by further adding the organic solvent and adjusting the viscosity can be used.

Hereinafter, the present invention will be described based on experimental examples.
This will be described more specifically.

[0098]

EXPERIMENTAL EXAMPLE 1 Experimental example 1 relates to a multilayer ceramic capacitor, and employs a primary dispersion step and a secondary dispersion step as a feature of the present invention in the production of a ceramic paste for a ceramic green layer for absorbing a level difference. This was performed to confirm the effect of the above.

(Preparation of Ceramic Powder) First, barium carbonate (BaCO ₃ ) and titanium oxide (TiO ₂ ) were weighed so as to have a molar ratio of 1: 1 and wet-mixed using a ball mill, followed by dehydration and drying. Was. Then the temperature 10
After calcining at 00 ° C. for 2 hours, the powder was ground to obtain a dielectric ceramic powder.

(Preparation of Ceramic Slurry and Preparation of Ceramic Green Sheet) 100 parts by weight of the previously prepared ceramic powder, 7 parts by weight of polyvinyl butyral having a medium polymerization degree and a high degree of butyralization, and DOP as a plasticizer
(Dioctyl phthalate) 3 parts by weight, methyl ethyl ketone 30 parts by weight, ethanol 20 parts by weight, toluene 2
0 parts by weight and 600 parts by weight of a zirconia cobblestone having a diameter of 1 mm were put into a ball mill and wet-mixed for 20 hours to obtain a dielectric ceramic slurry.

Then, a doctor blade method was applied to the dielectric ceramic slurry to form a 3 μm thick ceramic slurry.
A dielectric ceramic green sheet (having a thickness of 2 μm after firing) was formed. Drying was performed at 80 ° C. for 5 minutes.

(Preparation of conductive paste) Ag / Pd = 3
100 parts by weight of 0/70 metal powder, 4 parts by weight of ethyl cellulose, 2 parts by weight of alkyd resin, 3 parts by weight of Ag metal resinate (17.5 parts by weight as Ag), and 35 parts by weight of butyl carbitol acetate After kneading with three rolls, 35 parts by weight of terpineol was added to adjust the viscosity.

(Preparation of Ceramic Paste for Ceramic Green Layer for Absorbing Step) Sample 1 (Example) 100 parts by weight of the previously prepared dielectric ceramic powder and 70 parts by weight of methyl ethyl ketone (boiling point 79.6 ° C.) And 600 parts by weight of a zirconia ball having a diameter of 1 mm were charged into a ball mill and wet-mixed for 16 hours.

Next, the mixture was transferred to a stainless steel container and left to stand for one day to settle. After removing the supernatant, the precipitate was put in a convection oven and dried to remove methyl ethyl ketone as a solvent.

After completely removing methyl ethyl ketone,
A dielectric ceramic paste was obtained by kneading a mixture obtained by adding 40 parts by weight of terpineol (boiling point: 219.0 ° C.) and 5 parts by weight of an ethylcellulose resin with a three-roll mill. Then, for viscosity adjustment, 10 to 20 parts by weight of terpineol was added and dispersed and adjusted by an automatic mortar.

-Sample 2 (Example)-100 parts by weight of the previously prepared dielectric ceramic powder, 70 parts by weight of methyl ethyl ketone, and a quaternary ammonium polyacrylate ammonium salt dispersant (weight average molecular weight 1000) as an organic dispersant 0 0.5 parts by weight and 600 parts by weight of a zirconia cobblestone having a diameter of 1 mm were put into a ball mill and subjected to wet mixing for 16 hours.

Thereafter, through the same operation as in Sample 1, a dielectric ceramic paste was obtained.

-Sample 3 (Example)-100 parts by weight of the dielectric ceramic powder prepared above, 70 parts by weight of methyl ethyl ketone, and 600 parts by weight of zirconia balls having a diameter of 1 mm were put into a ball mill,
Wet mixing was performed for hours.

Next, the mixture was transferred to a stainless steel container and left to stand for one day to settle. After removing the supernatant, the precipitate was put in a convection oven and dried to remove methyl ethyl ketone.

After the methyl ethyl ketone has been completely removed,
Ethyl cellulose resin 5 by planetary mixer
A dielectric ceramic paste was obtained by kneading a mixture obtained by adding a resin solution in which 40 parts by weight of terpineol was previously dissolved, that is, an organic vehicle, with a three-roll mill. Then, for viscosity adjustment,
Terpineol was added in an amount of 10 to 20 parts by weight and dispersed and adjusted using an automatic mortar.

-Sample 4 (Example)-100 parts by weight of the previously prepared dielectric ceramic powder, 70 parts by weight of methyl ethyl ketone, and 600 parts by weight of a zirconia ball having a diameter of 1 mm were put into a ball mill,
Wet mixing was performed for hours.

Next, this mixture was subjected to an absolute filtration of 20 μm.
(The solid component of 10 μm or more can be removed with a probability of 99.7%.)

Next, the mixture after filtration was transferred to a stainless steel container, and left standing all day and night for sedimentation. And
After removing the supernatant, the sediment was placed in a convection oven and dried to remove methyl ethyl ketone.

After the methyl ethyl ketone has been completely removed,
40 parts by weight of terpineol and ethyl cellulose resin 5
The resulting mixture was kneaded with a three-roll mill to obtain a dielectric ceramic paste. Then, for viscosity adjustment, terpineol 10
-20 parts by weight were added and dispersed and adjusted using an automatic mortar.

-Sample 5 (Example)-100 parts by weight of the dielectric ceramic powder prepared above, 70 parts by weight of methyl ethyl ketone, and 600 parts by weight of a zirconia ball having a diameter of 1 mm were charged into a ball mill,
Wet mixing was performed for hours.

Next, this mixture was transferred to a stainless steel container, and left standing all day long to settle. After removing the supernatant, the precipitate was put in a convection oven and dried, and methyl ethyl ketone was removed to obtain a dried powder.

On the other hand, a resin solution in which 5 parts by weight of an ethylcellulose resin was previously dissolved in 40 parts by weight of terpineol by a planetary mixer was filtered through a filter having an absolute filtration of 20 μm to obtain an organic vehicle.

Next, the previously dried powder and this organic vehicle were mixed, and this mixture was kneaded with a three-roll mill to obtain a dielectric ceramic paste. Then
For viscosity adjustment, 10 to 20 parts by weight of terpineol was added and dispersed and adjusted by an automatic mortar.

-Sample 6 (Example)-100 parts by weight of the dielectric ceramic powder prepared above, 70 parts by weight of methyl ethyl ketone, 10 parts by weight of terpineol, and 600 parts by weight of a zirconia ball having a diameter of 1 mm were placed in a ball mill. The mixture was charged and wet-mixed for 16 hours.

Next, this mixture was transferred to a stainless steel container, and left standing all day and night for sedimentation. After removing the supernatant, the precipitate was put in a convection oven and dried to remove methyl ethyl ketone.

After completely removing methyl ethyl ketone,
30 parts by weight of terpineol and ethyl cellulose resin 5
The resulting mixture was kneaded with a three-roll mill to obtain a dielectric ceramic paste. Then, for viscosity adjustment, about 1 terpineol
0 parts by weight were added and dispersed and adjusted by an automatic mortar.

-Sample 7 (Comparative Example)-100 parts by weight of the dielectric ceramic powder prepared above, 40 parts by weight of terpineol, and 5 parts by weight of ethylcellulose resin were mixed in an automatic mortar, and then mixed with three rolls. By kneading, a dielectric ceramic paste was obtained.

(Preparation of Multilayer Ceramic Capacitor) In order to form internal electrodes on the main surface of the previously prepared dielectric ceramic green sheet, a conductive paste was screen-printed and dried at 80 ° C. for 10 minutes. The dimensions, shape and position of the internal electrodes were set so as to be compatible with the laminated chip obtained in a later step. Next, in order to form a dielectric ceramic green layer for step absorption on the main surface of the dielectric ceramic green sheet, each dielectric ceramic paste according to Samples 1 to 7 was screen-printed and dried at 80 ° C. for 10 minutes. Each thickness of the internal electrode and the dielectric ceramic green layer for absorbing a level difference is 1 μm after drying.
m (the thickness after firing is 0.5 μm).

Next, as described above, the internal electrodes and the step-absorbing dielectric ceramic green layer 200 are formed.
The dielectric ceramic green sheets are stacked so as to be sandwiched by several tens of dielectric ceramic green sheets to which internal electrodes and the like are not provided, to produce a raw laminate, and the laminate is 1000 kg at 80 ° C. / Cm ² under pressure.

Next, the above-mentioned green laminate was cut with a cutting blade so as to have a size of 3.2 mm in length × 1.6 mm in width × 1.6 mm in thickness after firing, thereby forming a plurality of laminates. I got a body chip.

Next, on the firing setter on which a small amount of zirconia powder was sprayed, the above-mentioned plurality of laminated chips were aligned, and the temperature was raised from room temperature to 250 ° C. over 24 hours to remove the organic binder. Next, the laminated chip was put into a firing furnace and fired at a maximum of 1300 ° C. for a profile of about 20 hours.

Next, the obtained sintered body chip was placed in a barrel, and after polishing the end face, external electrodes were provided at both ends of the sintered body to complete a multilayer ceramic capacitor as a sample.

(Evaluation of Characteristics) Various characteristics were evaluated for the dielectric ceramic pastes and multilayer ceramic capacitors according to Samples 1 to 7 described above. The results are shown in Table 1.

[0129]

[Table 1]

The characteristics evaluation in Table 1 was performed as follows.

"Solids": Approximately 1 g of the ceramic paste was precisely weighed and calculated from the weight after standing at 150 ° C. for 3 hours in a thermal convection oven.

"Viscosity": The viscosity of the ceramic paste
1. Using a Tokyo Keiki E-type viscometer at 20 ° C.
The measurement was performed by applying a rotation of 5 rpm.

"Degree of dispersion": The particle size distribution of the ceramic powder was measured using an optical diffraction type particle size distribution analyzer, and calculated from the obtained particle size distribution. That is, the previously prepared ceramic powder is dispersed in water using an ultrasonic homogenizer, and ultrasonic waves are applied until the particle diameter does not decrease any further, and the particle diameter of D90 at that time is recorded, and this is recorded. The limit particle size was used. On the other hand, the ceramic paste was diluted in ethanol, and the particle size distribution of D90 in the particle size distribution was recorded and used as the particle size of the paste. Then, the degree of dispersion was calculated based on the formula: degree of dispersion = (granule diameter of paste / critical particle diameter) −1. If the numerical value of the dispersion is +, the closer the value is to 0, the better the dispersibility is. If the numerical value is-, the larger the absolute value is, the better the dispersibility is.

"Print thickness": On a 96% alumina substrate,
Using a 400 mesh, 50 μm thick stainless steel screen, print at an emulsion thickness of 20 μm,
By drying for 0 minutes, a print film for evaluation is formed,
The thickness was determined from a measurement result by a specific contact type laser surface roughness meter.

"Ra (surface roughness)": The above "print thickness"
Is formed, and the surface roughness Ra, that is, the value obtained by averaging the absolute value of the deviation between the center line and the roughness curve obtained by averaging the waviness is determined by the specific contact method. It was determined from the measurement result by a laser surface roughness meter.

"Structural defect defect rate": When an abnormality was observed in the appearance inspection of the sintered chip for the obtained multilayer ceramic capacitor and the inspection by an ultrasonic microscope, the internal structural defect was confirmed by polishing. (Number of sintered chips having structural defects) / (total number of sintered chips) was defined as the structural defect defect rate.

Referring to Table 1, according to the samples 1 to 6 according to the embodiment of the present invention, in which the first dispersion step and the second dispersion step were adopted, and the organic binder was added in the second dispersion step, Excellent dispersibility can be obtained as compared with Sample 7 as a comparative example in which this was not performed.
It can be seen that excellent results are shown in each item of the print thickness, the surface roughness, and the structural defect defect rate.

[0138]

[Experimental Example 2] Experimental Example 2 relates to a multilayer ceramic inductor, and employs a primary dispersion step and a secondary dispersion step as features of the present invention in the production of a ceramic paste for a ceramic green layer for absorbing a step. This was performed to confirm the effect of the above.

(Preparation of ceramic powder)
After weighing 9.0 mol%, zinc oxide 29.0 mol%, nickel oxide 14.0 mol%, and copper oxide 8.0 mol%, and wet-mixing using a ball mill,
It was dehydrated and dried. Next, the powder was calcined at 750 ° C. for 1 hour and then pulverized to obtain a magnetic ceramic powder.

(Preparation of Ceramic Slurry and Preparation of Ceramic Green Sheet) 100 parts by weight of the magnetic ceramic powder previously prepared, 0.5 part by weight of a dispersant comprising a maleic acid copolymer, 30 parts by weight of methyl ethyl ketone and toluene 20 m parts by weight of a solvent having a diameter of 1 m
and 600 parts by weight of zirconia-made cobblestone, and stirred for 4 hours, then 7 parts by weight of polyvinyl butyral having a medium polymerization degree and a high degree of butyralization as an organic binder, 3 parts by weight of DOP as a plasticizer, and ethanol. 20 parts by weight and wet mixing for 20 hours to obtain a magnetic ceramic slurry.

Then, a doctor blade method was applied to the magnetic ceramic slurry to form a 20 μm thick magnetic ceramic slurry.
A magnetic ceramic green sheet (having a thickness of 15 μm after firing) was formed. Drying was performed at 80 ° C. for 5 minutes.

(Preparation of conductive paste) Ag / Pd = 8
100 parts by weight of a 0/20 metal powder, 4 parts by weight of ethyl cellulose, 2 parts by weight of an alkyd resin, and 35 parts by weight of butyl carbitol acetate were kneaded with a three-roll mill, and 35 parts by weight of terpineol were added. Adjustments were made.

(Preparation of Ceramic Paste for Ceramic Green Layer for Absorbing Step) Sample 8 (Example) 100 parts by weight of the magnetic ceramic powder prepared above, 70 parts by weight of methyl ethyl ketone, and zirconia having a diameter of 1 mm 600 parts by weight of a cobblestone are put into a ball mill,
Wet mixing was performed for hours.

Next, the mixture was transferred to a stainless steel container and left to stand for one day to settle. After removing the supernatant, the precipitate was put in a convection oven and dried to remove methyl ethyl ketone as a solvent.

After completely removing the methyl ethyl ketone,
40 parts by weight of terpineol and ethyl cellulose resin 5
The resulting mixture was kneaded with a three-roll mill to obtain a magnetic ceramic paste. Then, for viscosity adjustment, terpineol 10
-20 parts by weight were added and dispersed and adjusted using an automatic mortar.

-Sample 9 (Example)-100 parts by weight of the magnetic ceramic powder prepared above, 70 parts by weight of methyl ethyl ketone, and a quaternary ammonium polyacrylate ammonium salt dispersant (weight average molecular weight 1000) as an organic dispersant 0 0.5 parts by weight and 600 parts by weight of a zirconia cobblestone having a diameter of 1 mm were charged into a ball mill, and wet-mixed for 16 hours.

Thereafter, through the same operation as in Sample 1, a magnetic ceramic paste was obtained.

-Sample 10 (Example)-100 parts by weight of the magnetic ceramic powder prepared above, 70 parts by weight of methyl ethyl ketone, and 600 parts by weight of zirconia balls having a diameter of 1 mm were put into a ball mill,
Wet mixing was performed for hours.

Next, this mixture was transferred to a stainless steel container, and left standing all day and night for sedimentation. After removing the supernatant, the precipitate was put in a convection oven and dried to remove methyl ethyl ketone.

After removing methyl ethyl ketone completely,
Ethyl cellulose resin 5 by planetary mixer
A mixture obtained by adding a resin solution in which 40 parts by weight of terpineol was previously dissolved, that is, an organic vehicle, was kneaded with a three-roll mill to obtain a magnetic ceramic paste. Then, for viscosity adjustment,
Terpineol was added in an amount of 10 to 20 parts by weight and dispersed and adjusted using an automatic mortar.

-Sample 11 (Example)-100 parts by weight of the magnetic ceramic powder prepared above, 70 parts by weight of methyl ethyl ketone, and 600 parts by weight of a zirconia ball having a diameter of 1 mm were put into a ball mill,
Wet mixing was performed for hours.

Next, the mixture was filtered under pressure through a filter having an absolute filtration of 20 μm.

Next, the mixture after filtration was transferred to a stainless steel container, and left standing all day and night for sedimentation. And
After removing the supernatant, the sediment was placed in a convection oven and dried to remove methyl ethyl ketone.

After removing methyl ethyl ketone completely,
40 parts by weight of terpineol and ethyl cellulose resin 5
The resulting mixture was kneaded with a three-roll mill to obtain a magnetic ceramic paste. Then, for viscosity adjustment, terpineol 10
-20 parts by weight were added and dispersed and adjusted using an automatic mortar.

-Sample 12 (Example)-100 parts by weight of the magnetic ceramic powder prepared above, 70 parts by weight of methyl ethyl ketone, and 600 parts by weight of zirconia balls having a diameter of 1 mm were charged into a ball mill,
Wet mixing was performed for hours.

Next, the mixture was transferred to a stainless steel container and left to stand for one day to settle. After removing the supernatant, the precipitate was put in a convection oven and dried, and methyl ethyl ketone was removed to obtain a dried powder.

On the other hand, a resin solution in which 5 parts by weight of an ethylcellulose resin was previously dissolved in 40 parts by weight of terpineol by a planetary mixer was filtered through a filter having an absolute filtration of 20 μm to obtain an organic vehicle.

Next, the dried powder and the organic vehicle were mixed, and the mixture was kneaded with a three-roll mill to obtain a magnetic ceramic paste. Then
For viscosity adjustment, 10 to 20 parts by weight of terpineol was added and dispersed and adjusted by an automatic mortar.

-Sample 13 (Comparative Example)-100 parts by weight of the magnetic ceramic powder prepared above, 40 parts by weight of terpineol, and 5 parts by weight of ethylcellulose resin were mixed in an automatic mortar, and then mixed with three rolls. The mixture was kneaded to obtain a magnetic ceramic paste.

(Preparation of Multilayer Ceramic Inductor) Via-hole conductors are placed at predetermined positions on the previously prepared magnetic ceramic green sheet so that a coil conductor extending in a coil shape can be formed after laminating a plurality of magnetic ceramic green sheets. A conductive paste was screen-printed and dried at 80 ° C. for 10 minutes in order to form a through hole for forming a coil conductor film on the main surface of the magnetic ceramic green sheet and a via hole conductor in the through hole. Next, in order to form a step-absorbing magnetic ceramic green layer on the magnetic ceramic green sheet, the magnetic ceramic pastes of Samples 8 to 13 were screen-printed and dried at 80 ° C. for 10 minutes. The thickness of each of the coil conductor film and the step-absorbing magnetic ceramic green layer is 30 μm after drying (the thickness after firing is 2 μm).
0 μm).

Next, as described above, the eleven magnetic ceramic green sheets forming the coil conductor film, the via hole conductor, and the step-absorbing ceramic green layer are overlapped so that the coil conductor is formed.
A raw ceramic laminate is formed by laminating magnetic ceramic green sheets on which no coil conductor film or the like has been formed.
This laminate was hot-pressed at 80 ° C. under a pressure of 1000 kg / cm ² .

Next, the above-mentioned green laminate was cut with a cutting blade so as to have a size of 3.2 mm in length × 1.6 mm in width × 1.6 mm in thickness after firing, whereby a plurality of laminates were cut. I got a body chip.

Next, the above-mentioned laminated chip was heated at 400 ° C. for 2 hours.
After removing the organic binder by heating for a period of time, baking was performed at 920 ° C. for 90 minutes.

Next, the obtained sintered body chip was put into a barrel, and the end face was polished. After that, external electrodes mainly composed of silver were provided at both ends of the sintered body to form a chip-shaped sample. Completed a multilayer ceramic inductor.

(Evaluation of Characteristics) Samples 8 to 13
Table 2 shows the results of evaluating various characteristics of the ceramic paste and the multilayer ceramic inductor according to the above.

[0166]

[Table 2]

The characteristics evaluation method in Table 2 is the same as that in Table 1.

Referring to Table 2, Experimental Example 1 shown in Table 1 was obtained.
As in the case of the above, according to the samples 8 to 12 according to the embodiment of the present invention in which the primary dispersion step and the secondary dispersion step are employed, and the organic binder is added in the secondary dispersion step, such a phenomenon can be solved. Excellent dispersibility can be obtained as compared with Sample 13 as a comparative example which was not performed.
It can be seen that excellent results are shown in each item of the surface roughness and the structural defect defect rate.

As described above, the case where the dielectric ceramic powder or the magnetic ceramic powder is used as the ceramic powder contained in the ceramic paste according to the present invention has been described. However, in the present invention, the electric characteristics of the ceramic powder used are influenced by the ceramic powder. Therefore, even if, for example, an insulating ceramic powder or a piezoelectric ceramic powder is used, a ceramic paste that can be expected to have the same effect can be obtained.

[0170]

As described above, according to the present invention, in producing a ceramic paste, a primary dispersion step of subjecting a primary mixture containing at least a ceramic powder and a first organic solvent to a dispersion treatment, After the dispersing step, a removing step of selectively removing the first organic solvent from the primary mixture by heating, and after the removing step, an organic binder is added to the primary mixture from which the first organic solvent has been removed. Since the secondary dispersion step of dispersing the secondary mixture and the step of including the primary mixture and / or the secondary mixture with the second organic solvent having a higher boiling point than the first organic solvent are performed, the ceramic paste is used. Can have excellent dispersibility of the ceramic powder contained therein. Therefore, when a very thin ceramic green layer must be formed with high pattern accuracy, such a ceramic paste can be advantageously used.

Therefore, according to the present invention, in the multilayer ceramic electronic component, the internal circuit element film is not formed on the main surface of the ceramic green sheet so as to substantially eliminate the step due to the thickness of the internal circuit element film. To form a step absorption ceramic green layer in the area,
By using the ceramic paste as described above, a highly reliable multilayer ceramic electronic component free from structural defects such as cracks and delaminations can be realized.

Further, according to the present invention, it is possible to sufficiently cope with the demand for miniaturization and weight reduction of a multilayer ceramic electronic component. When the present invention is applied to a multilayer ceramic capacitor, It is possible to advantageously reduce the size and increase the capacity, and when the present invention is applied to a multilayer ceramic inductor, it is possible to advantageously reduce the size and increase the inductance of the multilayer ceramic inductor.

When the second organic solvent having a high boiling point is added in the secondary dispersion step, the first organic mixture can be prevented from being present in the primary mixture in the removal step. Organic solvent can be more easily removed.

In the case described above, the organic binder is added in a state of being dissolved in the second organic solvent in advance, or more preferably, after the organic binder previously dissolved in the second organic solvent is filtered. In this case, the amount of undissolved organic binder that can be mixed into the ceramic paste can be reduced.

On the other hand, when the primary mixture dispersed in the primary dispersion step further contains a second organic solvent, a decrease in the viscosity of the primary mixture due to the second organic solvent can be expected. When the next dispersion step is performed, an improvement in the dispersibility of the ceramic powder due to the decrease in the viscosity can be expected.

In the above case, the boiling point of the first organic solvent and the second
By making the difference from the boiling point of the organic solvent 50 ° C. or higher, the selective removal of only the first organic solvent by heat treatment in the removing step can be further facilitated.

In the present invention, if the step of preparing the ceramic paste further includes a step of filtering the primary mixture after the primary dispersion step and before the removing step, It is possible to remove foreign substances, agglomerates of ceramic powder, and the like, which may be mixed in the ceramic paste, and to reliably obtain a ceramic paste having higher dispersibility. Further, an effect of reducing pinholes in the fired ceramic layer can also be expected.

Further, in the method for manufacturing a multilayer ceramic electronic component according to the present invention, the ceramic slurry used for forming the ceramic green sheet may be a ceramic paste for forming a step-absorbing ceramic green layer. By including the ceramic powder having substantially the same composition as the powder, the sintering properties of the ceramic green sheet and the step absorbing ceramic green layer can be matched, and cracks due to such sintering mismatch and The occurrence of delamination can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating a part of a green laminate 3a for explaining a method of manufacturing a multilayer ceramic capacitor according to an embodiment of the present invention, which is of interest to the present invention. .

FIG. 2 is a plan view showing a part of a composite structure 6 manufactured in the method for manufacturing the multilayer ceramic capacitor shown in FIG.

FIG. 3 is a cross-sectional view schematically showing a multilayer chip 4a manufactured in the method for manufacturing the multilayer ceramic capacitor shown in FIG.

FIG. 4 shows a green laminate 13 prepared for manufacturing a multilayer ceramic inductor according to another embodiment of the present invention.
FIG. 2 is an exploded perspective view showing components constituting the device.

5 is a perspective view showing the appearance of a multilayer ceramic inductor 11 including a multilayer chip 12 obtained by firing the raw multilayer body 13 shown in FIG.

FIG. 6 is a cross-sectional view schematically illustrating a part of a green laminate 3 for explaining a method of manufacturing a conventional multilayer ceramic capacitor that is of interest to the present invention.

7 is a plan view showing a part of a ceramic green sheet 2 on which an internal electrode 1 is formed, which is manufactured in the method for manufacturing a multilayer ceramic capacitor shown in FIG.

8 is a cross-sectional view schematically showing a multilayer chip 4 manufactured in the method for manufacturing the multilayer ceramic capacitor shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Internal electrode (internal circuit element film) 2, 14-19 Ceramic green sheet 3a, 13 Raw laminated body 4a, 12 Laminated chip 5, 22, 25, 28, 30 Ceramic green layer for step difference absorption 6 Composite structure 11 Multilayer ceramic inductors (multilayer ceramic electronic components) 20, 23, 26, 29 Coil conductor film (internal circuit element film)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H01F 17/00 H01G 4/30 311F 5E062 41/04 B28B 11/00 Z 5E070 H01G 4/30 311 C04B 35 / 00 Y 5E082 (72) Koji Kimura Inventor, Murata Manufacturing Co., Ltd. 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto (72) Koji Kato 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto, Japan Murata Manufacturing Co., Ltd. 72) Inventor Hiroyuki Suzuki 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. (Reference) DC05 DC06 4G054 AA06 AB01 BA02 BA32 4G055 AA08 AB01 AC09 BA22 BA87 BB12 5E001 AB03 AH05 AJ01 AJ02 5E062 DD04 5 E070 AA01 AB02 BA12 BB03 CB03 CB13 CB17 5E082 AB03 BC39 EE04 EE11 EE23 EE35 FF05 FG06 FG26 FG54 KK01 LL02 MM21 MM22 MM24

Claims (13)

[Claims] 1. A ceramic green sheet obtained by preparing a ceramic slurry, a conductive paste, and a ceramic paste, and forming the ceramic slurry, and providing a step on the main surface of the ceramic green sheet due to its thickness. And an internal circuit element film formed by partially applying the conductive paste, and the main surface of the ceramic green sheet so as to substantially eliminate a step due to the thickness of the internal circuit element film. Producing a plurality of composite structures, comprising a step absorption ceramic green layer formed by applying the ceramic paste to a region where the internal circuit element film is not formed, and stacking the plurality of the composite structures. To produce a raw laminate, and firing the raw laminate A method of manufacturing a multilayer ceramic electronic component, comprising: a step of preparing a ceramic paste;
A primary dispersion step of dispersing the next mixture, a removal step of selectively removing the first organic solvent from the primary mixture by heating after the primary dispersion step, and after the removal step, A secondary dispersion step of subjecting the secondary mixture obtained by adding an organic binder to the primary mixture from which the first organic solvent has been removed, to the second organic solvent having a higher boiling point than the first organic solvent; And a step of including the secondary mixture and / or the secondary mixture. 2. The method for manufacturing a multilayer ceramic electronic component according to claim 1, wherein in the secondary dispersion step, the second organic solvent is added. 3. The method for manufacturing a multilayer ceramic electronic component according to claim 2, wherein, in the secondary dispersion step, the organic binder is added in a state of being dissolved in the second organic solvent in advance. 4. The organic binder previously dissolved in the second organic solvent is added after being filtered.
3. The method for producing a multilayer ceramic electronic component according to item 1. 5. The primary mixture subjected to dispersion treatment in the primary dispersion step further includes the second organic solvent, and in the removal step, the first mixture is left with the second organic solvent remaining. The method for manufacturing a multilayer ceramic electronic component according to claim 1, wherein the organic solvent is removed from the primary mixture. 6. The difference between the boiling point of the first organic solvent and the boiling point of the second organic solvent is 50 ° C. or more.
3. The method for producing a multilayer ceramic electronic component according to item 1. 7. The method according to claim 1, wherein the step of preparing the ceramic paste further comprises a step of filtering the primary mixture after the primary dispersion step and before the removing step. A method for producing the multilayer ceramic electronic component according to any one of the above. 8. The production of a multilayer ceramic electronic component according to claim 1, wherein the ceramic slurry includes a ceramic powder having substantially the same composition as the ceramic powder contained in the ceramic paste. Method. 9. The ceramic powder contained in each of the ceramic slurry and the ceramic paste,
9. The method for manufacturing a multilayer ceramic electronic component according to claim 1, wherein both are a dielectric ceramic powder. 10. The multi-layer ceramic electronic component according to claim 9, wherein the internal circuit element films are internal electrodes arranged so as to form a capacitance therebetween, and the multilayer ceramic electronic component is a multilayer ceramic capacitor. The manufacturing method of the multilayer ceramic electronic component according to the above. 11. The method according to claim 1, wherein the ceramic powder contained in the ceramic slurry and the ceramic powder contained in the ceramic paste are both magnetic ceramic powders. 12. The method of manufacturing a multilayer ceramic electronic component according to claim 11, wherein the internal circuit element film is a coil conductor film extending in a coil shape, and the multilayer ceramic electronic component is a multilayer ceramic inductor. . 13. A multilayer ceramic electronic component obtained by the manufacturing method according to claim 1. Description: