TWI588853B - Multilayer Ceramic Capacitor Internal electrode paste and laminated ceramic capacitor - Google Patents

Description

Multilayer ceramic capacitor internal electrode paste and laminated ceramic capacitor

The present invention relates to a paste for an internal electrode of a multilayer ceramic capacitor and a laminated ceramic capacitor.

A multilayer ceramic capacitor is one of electronic components that have been used in the past.

The multilayer ceramic capacitor generally has a structure in which a dielectric layer and an internal electrode layer are alternately laminated. For example, a multilayer ceramic capacitor can be produced by a manufacturing method including the following steps.

A step of producing green sheets (dielectric green sheets) containing a dielectric powder such as barium titanate and an organic binder.

The internal electrode paste is applied to the surface of the green sheet and dried according to the desired internal electrode pattern.

The internal electrode and the green sheet are alternately laminated, and then thermocompression bonding is performed, and the thermocompression bonded body is cut into a target size.

In order to remove the organic binder, the step of heating to remove the organic binder.

The step of firing to sinter the internal electrode and the dielectric body.

Mounting an external electrode for bonding an external device on the obtained multilayer ceramic capacitor element step.

In the internal electrode paste used for forming the internal electrode of the laminated ceramic capacitor, for example, Patent Document 1 discloses a conductive paste composition containing a conductive powder, a common material, and an organic binder, which is derived from Pd. And a metal powder or/and an alloy powder selected from the group consisting of Ag, Ni, and Cu, the composite material comprising a component common to a material constituting the dielectric sheet, the organic binder being composed of a resin, an organic solvent, and an organic additive. The resin is a resin selected from the group consisting of ethyl cellulose, methyl cellulose, polyvinyl butyral, and propylene polymer, and the organic additive has an octadecyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, and an oleyl alcohol. The lipophilic group selected in the oleyl group and the hydroxyester structure of the polyethylene glycol moiety.

Patent Document 1: Japanese Patent Laid-Open Publication No. 2004-200449

However, when the conventional internal electrode paste is used, the adhesion between the internal electrode and the dielectric layer obtained by firing the green sheet may not be sufficient. Therefore, for example, in the production of a multilayer ceramic capacitor, or after the production of the multilayer ceramic capacitor, peeling may occur between the internal electrode and the dielectric layer.

Here, an object of one aspect of the present invention is to provide a laminated ceramic capacitor internal electrode paste which can form an internal electrode having good adhesion to a dielectric layer.

In order to achieve the above object, according to one aspect of the present invention, a paste for a built-in ceramic capacitor internal electrode containing nickel powder, polyvinyl butyral, and ethyl cellulose is provided. When the content of the final content is 100 parts by mass, the content of the polyvinyl butyral is 1.0 part by mass or more, and the content of the ethyl cellulose is less than 6.0 parts by mass.

According to an aspect of the present invention, it is possible to provide a laminated ceramic capacitor internal electrode paste which can form an internal electrode having good adhesion to a dielectric layer.

10‧‧‧Multilayer ceramic capacitors

11‧‧‧ dielectric layer

12‧‧‧Internal electrodes

13‧‧‧External electrode

Fig. 1 is a schematic cross-sectional view showing a multilayer ceramic capacitor according to an embodiment of the present invention.

The embodiments of the present invention are described below with reference to the drawings, and the present invention is not limited to the embodiments described below, and various modifications and substitutions may be made to the embodiments described below without departing from the scope of the invention.

[Laminating ceramic capacitor internal electrode paste]

A configuration example of the paste for the internal electrode of the multilayer ceramic capacitor of the present embodiment will be described.

The paste for the internal electrode of the multilayer ceramic capacitor of the present embodiment may contain nickel powder, polyvinyl butyral or ethyl cellulose.

When the content of the nickel powder is preferably 100 parts by mass, the content of the polyvinyl butyral is 1.0 part by mass or more, and the content of the ethyl cellulose is less than 6.0 parts by mass.

Each component contained in the paste for a built-in ceramic capacitor internal electrode of the present embodiment (hereinafter also simply referred to as "internal electrode paste") will be described.

(nickel powder)

Nickel powder can be added to the internal electrode paste of the present embodiment. By adding a nickel powder, it is possible to impart conductivity to the internal electrode formed using the internal electrode paste.

The particle diameter of the nickel powder is not particularly limited, and it can be considered in the paste for internal electrodes. The dispersibility, the workability when applied to a green sheet, or the like, the conductivity at the time of firing to form an internal electrode, and the like are arbitrarily selected.

In particular, in order to be able to correspond to a high-layered, high-capacity multilayer ceramic capacitor, The average particle diameter is preferably 0.05 μm or more and 1.0 μm or less. In addition, the average particle diameter as used herein means a value obtained by a scanning electron microscope (SEM) image, and represents a particle diameter of 50% of the integral value in the particle size distribution. The average particle size of other parts of the specification also means this.

By making the average particle diameter of the nickel powder 1.0 μm or less, internal electricity can be made Since the thickness of the electrode is extremely thin, it is easy to achieve thinning of the multilayer ceramic capacitor. In addition, by making the average particle diameter of the nickel powder 0.05 μm or more, it is possible to suppress the surface activity of the nickel powder from becoming excessively high, and it is possible to suppress the viscosity of the internal electrode paste from becoming high. In addition, it is possible to suppress deterioration or the like when the internal electrode paste is stored for a long period of time.

The content of the nickel powder in the paste for internal electrodes is not particularly limited, and it is not limited. The viscosity of the internal electrode paste is arbitrarily selected depending on the required viscosity, the conductivity required as the internal electrode, and the like. In particular, the amount of the internal electrode paste is preferably 30% by mass or more and 70% by mass or less, more preferably 40% by mass or more and 60% by mass or less.

The reason is that the content of the nickel powder in the internal electrode paste is 30% by mass. In the above case, the electrode film forming ability at the time of firing the internal electrode paste can be sufficiently ensured, and the desired capacitor capacity can be obtained more reliably. In addition, by making the content of the nickel powder in the internal electrode paste 70% by mass or less, it is easy to achieve thinning of the electrode film of the internal electrode.

(organic resin)

The internal electrode paste of the present embodiment may contain an organic resin, and the organic resin is preferably a mixed system of ethyl cellulose (EC) and polyvinyl butyral (PVB).

Ethyl cellulose (EC) has good solvent solubility ‧ printability ‧ burning Since it is decomposable, etc., it is suitable as a binder of the internal electrode paste. Further, as the organic resin, by using polyvinyl butyral (PVB) for the green sheet together, the adhesion strength between the green sheet and the internal electrode paste-dried film can be improved.

According to the study by the inventors of the present invention, the content of nickel powder is 100 mass. In the case of the portion, the content of the polyvinyl butyral (PVB) is preferably 1.0 part by mass or more, and the content of the base cellulose (EC) is less than 6.0 parts by mass. In particular, when the content of the nickel powder is 100 parts by mass, the content of the polyvinyl butyral (PVB) is preferably 2.0 parts by mass or more, and the content of the ethyl cellulose (EC) is 5.0 parts by mass or less.

The reason is that by making the content of polyvinyl butyral (PVB) 1.0 mass In addition, the content of the ethyl cellulose (EC) is less than 6.0 parts by mass, and in particular, the adhesion strength between the green sheet and the internal electrode paste-dried film can be improved, which is preferable. Further, by increasing the adhesion strength between the green sheet and the internal electrode paste-dried film, the dielectric layer obtained by firing the green sheet and the internal electrode obtained by firing the internal electrode paste-dried film can be improved. The closeness.

The upper limit of the content of the polyvinyl butyral (PVB) is not particularly limited. however, The dry film density of the internal electrode paste-dried film may decrease as the content increases. Therefore, when the content of the nickel powder is 100 parts by mass, it is preferably 5.0 parts by mass or less. Further, it is more preferably 4.0 parts by mass or less, still more preferably 3.5 parts by mass or less.

Further, the lower limit of the ethyl cellulose (EC) content is not particularly limited. When the content of the nickel powder is 100 parts by mass, it may be more than 0 parts by mass, preferably 1 part by mass or more, more preferably 2 parts by mass or more.

About the content of polyvinyl butyral (PVB) contained in organic resin and ethyl fiber The ratio of the content of the vitamin (EC) is not particularly limited and can be arbitrarily set. In particular, it is preferred that the mass ratio of the content of the polyvinyl butyral to the content of the ethyl cellulose satisfies the relationship of the following formula (1).

0.2≦ (content of polyvinyl butyral) / (content of ethyl cellulose) ‧‧‧式(1)

As described above, by adding polyvinyl butyral as the organic resin, the adhesion between the internal electrode paste-dried film and the green sheet can be improved. Moreover, according to the study by the inventors of the present invention, by setting the ratio of the mass ratio of the polyvinyl butyral in the organic resin to 0.2 or more, the adhesion strength between the green sheet and the internal electrode paste-dried film can be further improved. Therefore, the adhesion between the dielectric layer and the internal electrode can be improved.

In particular, the mass ratio (content of polyvinyl butyral) / (content of ethyl cellulose) is preferably 0.6 or more.

In addition, the upper limit of (content of polyvinyl butyral) / (content of ethyl cellulose) is not particularly limited, and from the viewpoint of improving solvent solubility, printability, and combustion decomposition property, it is preferably 5.0 or less, more preferably 4.0 or less.

Further, it is known that when the laminated ceramic capacitor is manufactured as described above, in order to form a desired electrode pattern on the green sheet, the internal electrode paste is applied by printing or the like, and a sheet attack occurs. The phenomenon.

As described below, the internal electrode paste may contain an organic solvent. In the case of the sheet intrusion, when the internal electrode paste is in contact with the green sheet, the organic binder (for example, polyvinyl butyral) used in the green sheet is dissolved by the organic solvent in the internal electrode paste. Sheet violation It is also a cause of delamination of the dielectric layer and the internal electrode during firing, and it is required to suppress the occurrence of sheet damage.

The inventors of the present invention have found that by using the internal electrode paste as an organic The total mass ratio of the polyvinyl butyral (PVB) and the ethyl cellulose (EC) of the resin is a certain ratio or more, and the occurrence of sheet damage can be suppressed. According to the study by the inventors of the present invention, the total content of the polyvinyl butyral and the content of the ethyl cellulose in the paste for the internal electrode of the multilayer ceramic capacitor is 2.5% by mass or more, and in particular, it is possible to suppress the sheet from being invaded. Occurs, so it is better. Further, when the amount is 3% by mass or more, it is more preferable to suppress the occurrence of sheet damage.

The reason is considered to be that polyethylene is used as an organic resin in the internal electrode paste. The content of the butene aldehyde (PVB) and the ethyl cellulose (EC) is equal to or higher than a predetermined ratio, and it is possible to suppress the penetration of the organic solvent in the internal electrode paste to the green sheet side.

Polyvinyl butyral (PVB) as an organic resin contained in the paste for internal electrodes and The upper limit of the content of the ethyl cellulose (EC) is not particularly limited and may be arbitrarily selected. For example, the total amount of the polyvinyl butyral content and the ethyl cellulose content in the paste for the internal electrode of the multilayer ceramic capacitor is preferably 5% by mass or less in consideration of the degumming property of the internal electrode paste.

Polyvinyl butyral (PVB) used in the internal electrode paste of the present embodiment and The physical properties of ethyl cellulose (EC), for example, the degree of polymerization, and the like are not particularly limited. From the viewpoint of handling properties at the time of printing and coating on the green sheets, it is preferred to select the materials so as to be suitable for the viscosity of the printing method or coating method to be used.

Nickel powder and organic which may be appropriately contained in the paste for internal electrodes of the present embodiment Although the resin has been described, the internal electrode paste of the present embodiment may further contain an optional component as needed. The internal electrode paste of the present embodiment is, for example, in addition to nickel powder and organic resin. It may contain the following ingredients.

(Organic solvents)

The internal electrode paste of the present embodiment may further contain an organic solvent. The material of the organic solvent is not particularly limited, and for example, a material capable of dissolving ethyl cellulose as an organic resin, polyvinyl butyral or the like to obtain an organic vehicle can be suitably used. In particular, when the internal electrode paste is printed or applied on the green sheet, an organic solvent having good drying properties is preferable in order to suppress the occurrence of sheet damage.

Therefore, when the internal electrode paste of the present embodiment is an organic solvent, As the organic solvent, a solvent which is compatible with polyvinyl butyral and ethyl cellulose and which has good drying properties is preferably used.

The organic vehicle can be easily prepared by selecting an organic solvent having this property. Further, when the internal electrode paste is printed or applied on the green sheet, it is preferable to cause the sheet to be invaded only by the sheet having no problem in characteristics.

As such an organic solvent, for example, rosinol (α, β, γ, and a mixture thereof) may be mentioned. Any of the compounds), octanol, decyl alcohol, tridecyl alcohol, dibutyl phthalate, butyl acetate, butyl carbitol, butyl carbitol acetate, petroleum hydrocarbons, and the like. As the organic solvent, rosinol (any of α, β, γ, and a mixture thereof) is particularly preferably used.

The amount of the organic solvent to be added is not particularly limited and can be arbitrarily selected, for example, from a special In view of suppressing the occurrence of sheet intrusion, the mass ratio of the content of the organic resin to the content of the organic solvent preferably satisfies the relationship of the following formula (2). Here, the content of the organic resin means the total of the content of polyvinyl butyral and the content of ethyl cellulose.

(content of organic solvent) / (content of organic resin) ≦15‧‧‧(2)

In particular, it is more preferable that the content of the organic solvent / the content of the organic resin is 14 or less. The reason for this is that the organic resin contained in the internal electrode paste has a function of suppressing the penetration of the organic solvent to the side of the green sheet. Therefore, the mass ratio of the organic solvent to the organic resin satisfies, for example, the above range, thereby suppressing sheet damage. It happens, so it is better.

The lower limit of the (content of the organic solvent) / (the content of the organic resin) is not particularly limited, and is preferably greater than 0 in order to form an organic vehicle.

(dielectric powder)

In the internal electrode paste of the present embodiment, the dielectric powder can be blended as an inorganic additive for the purpose of sintering shrinkage of the internal electrode at the time of firing and sintering shrinkage operation of the green sheet. Typically, dielectric material powder is also referred to as a total, for example, an appropriate amount of commercially available formulations _{BaTiO 3, BaTi x Zr 1-} x O 3 ( e.g. x 0.8) and the like, or ceramic green sheets of the same composition Other inorganic oxides, etc.

When the dielectric powder is added to the internal electrode paste of the present embodiment, the flattening is performed. The average particle diameter is not particularly limited and can be arbitrarily selected. In particular, when forming an internal electrode of a high-layered, high-capacity multilayer ceramic capacitor, the average particle diameter of the dielectric powder is preferably, for example, 0.01 μm or more and 0.1 μm or less.

Furthermore, as described above, it can be obtained by scanning electron microscope (SEM) image Average particle size, which represents a particle size of 50% of the integrated value in the particle size distribution.

By making the average particle diameter of the dielectric powder satisfy the above range, the inner diameter can be sufficiently reduced. The electric resistance value of the partial electrode can further form an electrode film of a uniform internal electrode, and the multilayer ceramic capacitor can have a desired electrostatic capacitance.

In addition, when a dielectric powder is added to the paste for internal electrodes, regarding the dielectric The content of the powder is not particularly limited, and it is preferably added so that the content of the dielectric powder in the internal electrode paste is 1% by mass or more and 30% by mass or less. The reason for this is that it is possible to sufficiently suppress the difference in sintering shrinkage when the internal electrode paste and the green sheet are simultaneously fired, and it is possible to suppress the cracking of the sintered body in particular. In addition, when the content is 30% by mass or less, the conductivity of the formed internal electrode can be surely ensured, and the multilayer ceramic capacitor can have a desired electrostatic capacitance.

(additive)

Further, any additive may be added to the internal electrode paste of the present embodiment. The additive is not particularly limited, and can be arbitrarily selected depending on the viscosity required for the internal electrode paste, the state of the nickel powder contained in the internal electrode paste, and the like.

As an additive, for example, in order to prevent the powder contained in the internal electrode paste As a set, a dispersing agent can be used. The dispersant is not particularly limited, and for example, a positive ion dispersant, an anion dispersant, or the like can be suitably used.

In addition, in the case where the dielectric powder is added as described above, in order to suppress nickel powder Separation from the dielectric powder, a separation inhibitor may also be added as an additive. As the separation inhibitor, for example, a polycarboxylic acid polymer or a constituent material containing a salt of a polycarboxylic acid can be used.

Separation inhibitors can be inhibited to some extent, for example by hydrogen bonding between carboxylic acids The dispersion of the powder particles in the paste enables the distance between the nickel powder which is initially uniformly stirred and the dielectric powder to be kept constant.

Moreover, by the hydrogen bond between the carboxylic acids, it is possible to increase the steady state (still state). The paste viscosity can thereby suppress separation of the nickel powder and the dielectric powder due to the difference in specific gravity.

When a separation inhibitor is added, the dispersibility as a whole paste is deteriorated. Aggregates of nickel powder and dielectric powder can occur. On the other hand, from the viewpoint of improving the dispersibility of the nickel powder and the dielectric powder, it is preferred to add a dispersant as described above.

The amount of each component added to the additive is not particularly limited, and may be added according to each An arbitrary amount is added for the purpose of addition of the agent or the like.

The components contained in the paste for internal electrodes of the present embodiment have been described. In order to ensure sufficient conductivity and film strength when the internal electrode is used as the internal electrode, the internal electrode paste of the present embodiment preferably has a large density after the internal electrode paste is applied onto the substrate and dried. Specifically, for example, after the internal electrode paste of the present embodiment is applied onto a substrate, the film density (dry film density) after drying at 120 ° C is preferably 4.75 g/ml or more, more preferably 4.80 ga/ml. the above.

Further, the substrate used for measuring the density of the dried film, and the inner electrode for coating The shape of the paste is not particularly limited. For example, various resins such as polyethylene terephthalate (PET) resin can be used as the substrate. Further, the internal electrode paste can be applied to the substrate by, for example, coating at a width of 50 mm, a length of 100 mm, and a thickness of 250 μm as described above at 120 ° C for measurement. The drying time is not particularly limited, and may be arbitrarily selected, and it is preferred to dry to such an extent that no weight change occurs during drying. For example, when the internal electrode paste is applied in the above-described size, it can be dried for 40 minutes.

According to the paste for a built-in ceramic capacitor internal electrode of the present embodiment described above, the adhesion strength between the green sheet and the dried film of the internal electrode paste can be improved during the production process. Further, it is possible to improve the adhesion between the dielectric layer in which the green sheet is fired and the internal electrode in which the internal electrode paste is fired. In other words, when the ceramic capacitor is laminated, an internal electrode having good adhesion to the dielectric layer can be formed.

Therefore, during or after the manufacture of the multilayer ceramic capacitor, for example, when used For example, it is possible to suppress the occurrence of peeling between the layers of the laminated body, and it is possible to improve the yield and durability of the laminated ceramic capacitor.

[Manufacturing method of paste for internal electrode of laminated ceramic capacitor]

Hereinafter, a configuration example of a method for producing a paste for a built-in ceramic capacitor internal electrode of the present embodiment will be described. In addition, the above-described multilayer ceramic capacitor internal electrode paste can be suitably produced by the method for producing a multilayer ceramic capacitor internal electrode paste of the present embodiment. Therefore, the portion overlapping with the description of the paste for the internal electrode of the multilayer ceramic capacitor will be partially omitted here.

The method for producing the internal electrode paste of the present embodiment is not particularly limited. The preparation can be carried out in any order.

For example, when the internal electrode paste contains an organic solvent as described above, the inside The method for producing an electrode paste may include the following steps.

The organic vehicle is prepared by dissolving the organic resin in an organic solvent to prepare an organic vehicle.

A dispersion step of adding nickel powder to an organic vehicle prepared by an organic carrier preparation step and dispersing it.

When the internal electrode paste contains a dielectric powder, an additive or the like, it is preferred to add a dielectric powder, an additive or the like to the organic vehicle in the dispersion step, and to disperse these components in the organic vehicle.

The following describes each step.

(Organic carrier preparation step)

The order of preparing the organic vehicle in the organic carrier preparation step is not particularly limited. For example, An organic vehicle containing an anthracene resin is prepared by simultaneously adding polyvinyl butyral (PVB) and ethyl cellulose (EC) to an organic solvent.

Further, an organic carrier of polyethylene butyral (PVB) and an ethyl group can also be separately prepared. Cellulose (EC) organic carrier. That is, the organic carrier preparation step may also include a polyvinyl butyral organic carrier preparation step and an ethyl cellulose organic carrier preparation step. In this case, the organic solvent for the organic carrier of polyvinyl butyral (PVB) and the organic carrier of ethyl cellulose (EC) is preferably the same material.

Furthermore, the organic solvent can be prepared for each organic resin in the dispersion step. The organic resin may be mixed with the prepared organic vehicle in advance by mixing with nickel powder or the like, and then supplied to the dispersion step.

The preparation step of the organic carrier comprises the steps of preparing a polyvinyl butyral organic carrier and The case of the ethyl cellulose organic carrier preparation step will be described as an example.

In the preparation step of the polyvinyl butyral organic carrier, for example, an organic tree can be prepared in advance Fatty polyvinyl butyral.

Then, the organic solvent is heated to a thermostat such as 50 ° C to 60 ° C, The polyvinyl butyral is slowly added to the organic solvent, continuously stirred and heated until the polyvinyl butyral is dissolved, whereby a polyvinyl butyral organic carrier can be prepared.

The procedure for preparing the ethylcellulose organic vehicle can be carried out in the same manner as the preparation of the polyvinyl butyral organic vehicle except that ethyl cellulose is used as the organic resin.

(dispersion step)

In the dispersing step, the organic vehicle prepared by the organic carrier preparation step and the nickel powder may be placed in a stirrer for stirring. Moreover, after stirring, it is preferably, for example, by a three-roll mill. The nickel powder or the like is more uniformly dispersed and mixed in the organic vehicle.

Further, when the organic vehicle and the nickel powder are placed in the agitator, as described above, for example, a dielectric powder, various additives, and the like may be simultaneously supplied.

By carrying out the above steps, the internal electrode paste of the embodiment can be manufactured.

[Laminated Ceramic Capacitor]

Next, a configuration example of a multilayer ceramic capacitor including an internal electrode formed using the above-described laminated ceramic capacitor internal electrode paste will be described.

A schematic cross-sectional view of the multilayer ceramic capacitor of the present embodiment is shown in Fig. 1 . 1 is a schematic cross-sectional view showing a plane passing through the center of the laminated ceramic capacitor 10 and parallel to the lamination direction of the dielectric layer 11 and the internal electrode 12. As shown in FIG. 1, the multilayer ceramic capacitor 10 of the present embodiment has a structure in which a dielectric layer 11 obtained by firing a green sheet and an internal electrode 12 obtained by firing the internal electrode paste are used. A structure that alternates with each other. In other words, the multilayer ceramic capacitor of the present embodiment is an internal electrode containing a fired product as the paste for the internal electrode of the multilayer ceramic capacitor. Further, on the outer surface of the multilayer ceramic capacitor 10, the external electrode 13 connected to the internal electrode 12 may be provided.

The method for producing the multilayer ceramic capacitor shown in FIG. 1 is not particularly limited, and it can be produced by a known method for producing various laminated ceramic capacitors. Specifically, for example, the following steps may be included.

A green sheet manufacturing step of producing a green sheet (dielectric body green sheet) containing a dielectric powder such as barium titanate and an organic binder.

Applying an internal electrode paste to the surface of the green sheet according to the pattern of the desired internal electrode The dried internal electrode forming step.

The internal electrode and the green sheet are alternately laminated, and then thermocompression bonding is performed, and the thermocompression bonded body is cut into a layered step of a target size.

In order to remove the organic binder, the degumming step of removing the organic binder is performed by heating.

A sintering step of sintering the internal electrode and the dielectric by firing.

An external electrode forming step for connecting an external electrode of an external device is mounted on the obtained multilayer ceramic capacitor element.

The organic binder used in the green sheet production step is not particularly limited, for example, From the viewpoint of particularly improving the adhesion to the internal electrode paste of the present embodiment, it is preferred to contain polyvinyl butyral.

Moreover, as a starting material for the green sheets used in the green sheet manufacturing step, In addition to the above dielectric powder and organic binder, a raw material to which an organic solvent, various dispersants, a plasticizer, a static remover, or the like is added may be used. Further, when an organic solvent is used as a starting material for the green sheet, it is preferred to dissolve the organic binder in an organic solvent in advance to prepare an organic vehicle. Then, a paste obtained by mixing a dielectric powder, various additives, and the like to the organic vehicle is preferably supplied to the green sheet manufacturing step.

Then, as the internal electrode paste used in the internal electrode forming step, it is preferably The above internal electrode paste was used.

There is no special limitation on the degumming step, the heating temperature of the sintering step, the environment, and the like. It can be arbitrarily selected according to the materials used.

In the multilayer ceramic capacitor of the embodiment, the above laminated ceramic capacitor is used. The internal electrode is made of a paste to form an internal electrode, so that the green sheet and the inside can be improved during the manufacturing process. The adhesion strength of the dried film of the electrode paste. In addition, it is also possible to improve the adhesion between the dielectric layer obtained by firing the green sheet and the internal electrode obtained by firing the internal electrode paste.

Therefore, during or after the manufacture of the multilayer ceramic capacitor, for example, when used For example, it is possible to suppress occurrence of interlayer peeling of the laminated body, and it is possible to improve the yield and durability of the laminated ceramic capacitor.

[Examples]

Hereinafter, the present invention will be further specifically described with reference to examples. The present invention is not limited to the following embodiments.

Here, first, the evaluation method of the sample in the following experimental examples will be described.

(dry film density)

In each of the following experimental examples, the prepared internal electrode paste was placed on a PET sheet, and an applicator having a width of 50 mm and a gauge slit of 250 μm was used and spread to a state of about 100 mm. Then, the paste was dried at 120 ° C for 40 minutes. The dried body was cut into four squares of 1 inch, and the PET sheet was peeled off, and then the thickness and weight of the four dried films were measured to calculate the dry film density.

Then, the dry film density was judged based on the calculated dry film density. dry The sample having a dry film density of 5.0 g/ml or more was judged to be ◎, 4.8 g/ml or more, and the sample which was less than 5.0 g/ml was judged to be ○, 4.75 g/ml or more, and the sample which was less than 4.8 g/ml was judged to be Δ. The sample which did not reach 4.75 g/ml was judged to be ×.

(adhesiveness)

First, 90% by weight of the finely divided barium titanate powder and a carrier composed of 4% by weight of polyvinyl butyral and 6% by weight of ethanol were kneaded to prepare a ceramic slurry. Then, by the scraping method On the PET film of the carrier sheet, the ceramic slurry was applied into a sheet having a thickness of 5 μm to prepare a green sheet.

Then, the internal electrodes prepared in the respective experimental examples were screen-printed with the paste on the above. On the green sheet, an internal electrode pattern having a WET thickness of 2 μm was formed on the green sheet. Then, the sheet on which the internal electrode pattern was formed on the green sheet was dried at 85 ° C for 10 minutes.

Then, formed in the same manner on the green sheets making a sheet with an internal electrode pattern were laminated, and at a temperature of 80 ℃, pressure of 1000kgf / cm ^2, final heat for 5 minutes then, made into a 20-layer internal electrodes Laminated body. This laminated body was cut into a square shape of 3 mm × 5 mm, and fired in an air oven at a temperature of 1,350 ° C for 2 hours to obtain a fired body. Then, the surface of the fired body was polished, and the cross section was observed by an optical microscope to determine the number of occurrences of delamination (interlayer peeling phenomenon). The number of delaminations in 50 samples was used to evaluate the number of delamination occurrences. When the number of samples in which delamination occurred was less than five, it was evaluated as ◎, five or more, and when it was less than 10, it was evaluated as ○, 10 or more, and when it was less than 25, it was evaluated as Δ, 25 or more, 50 The following cases were evaluated as ×.

(sheet violation)

First, 90% by weight of the finely divided barium titanate powder and a carrier composed of 4% by weight of polyvinyl butyral and 6% by weight of ethanol were kneaded to prepare a ceramic slurry. Then, the ceramic slurry was applied to a PET film as a carrier sheet by a doctor blade method to form a sheet having a thickness of 8 μm to prepare a green sheet.

Then, the internal electrode paste prepared in each experimental example was screen-printed on the green sheet, and an internal electrode pattern was formed on the green sheet to prepare a sample for sheet invasive evaluation.

Then, the obtained sample for evaluation of the sheet invasiveness was observed from the surface in contact with the PET film of the green sheet by a microscope, and the degree of dissolution of the green sheet was confirmed based on the degree of deformation and the color tone, and the degree of damage of the sheet was evaluated.

When observed by a microscope, the green sheets showed no deformation or color change, and no hair was emitted. The condition of the raw sheet infringement was evaluated as ○. The deformation or color tone change was observed in the range of less than 10% of the area of the green sheet, but the degree was not large, and the case where it did not affect the characteristics of the multilayer ceramic capacitor was evaluated as Δ. When the deformation or the color tone was changed in the range of 10% or more of the area of the green sheet, the case where the possibility of being a characteristic of the multilayer ceramic capacitor was high was evaluated as ×.

The production conditions and evaluation results of the samples of the respective experimental examples will be described below.

[Experimental Example 1-1 to Experimental Example 1-5]

In the experimental examples 1-1 to 1-5, the internal electrode paste was prepared in the following order and evaluated. Here, in Experimental Example 1-1 to Experimental Example 1-5, as shown in Table 1, an internal electrode paste was produced by the same method except that the amount of the components added was different.

Experimental Example 1-1 is a comparative example, and Experimental Example 1-2 to Experimental Example 1-5 are examples.

(Organic carrier preparation step)

In the organic carrier preparation step, a preparation step of preparing a polyvinyl butyral organic carrier containing an organic carrier of polyvinyl butyral, and a step of preparing an ethylcellulose organic carrier containing an organic carrier of ethyl cellulose are carried out.

In the polyvinyl butyral organic carrier preparation step, first, half of the addition amount shown in Table 1 was heated to 60 ° C on rosin alcohol (a mixture of α, β, and γ) as an organic solvent. Then, while stirring the heated rosin alcohol with a moving impeller (impeller), polyvinyl butyral was gradually added so as to be added in the amount shown in Table 1, thereby preparing an organic vehicle containing polyvinyl butyral.

In addition, in the preparation step of the ethyl cellulose organic carrier, the same is true The rosinol (mixture of α, β, γ) of the organic solvent was heated to 60 ° C in half of the amount shown in Table 1. Then, while stirring the heated rosin alcohol with a moving impeller (impeller), ethyl cellulose was gradually added so as to be added in the amount shown in Table 1, thereby preparing an organic vehicle containing ethyl cellulose.

Further, in Experimental Example 1-1, since polyvinyl butyral was not added, only the implementation was carried out. The procedure for preparing an ethylcellulose organic vehicle for preparing an organic vehicle containing ethyl cellulose, at this time, the organic solvent shown in Table 1 was used in the whole amount.

(dispersion step)

A dispersion step is then carried out.

In the dispersion step, first, an organic carrier prepared by an organic carrier preparation step, nickel powder, and BaTiO ₃ (barium titanate) as a dielectric powder are placed in a stirrer and stirred. Then, the obtained slurry was further completely dispersed using a three-roll mill.

Further, as described above, as the organic vehicle, the organic vehicle containing ethyl cellulose was used in Experimental Example 1-1, and the organic carrier containing polyvinyl butyral and the ethyl group were used in Experimental Examples 1-2 to 1-5. An organic carrier for cellulose.

Hereinafter, the conditions will be specifically described.

As the nickel powder, a commercially available nickel powder produced by a dry method was used. Further, the average particle diameter was determined by FE-SEM in advance to be 0.4 μm.

Further, as the BaTiO ₃ powder, a commercially available BaTiO ₃ powder was used, and the average particle diameter obtained by SEM in advance was 0.1 μm.

In each of the experimental examples, the constituent materials shown in Table 1 were weighed and placed in a stirrer for mixing.

Then, the obtained slurry was treated with a three-roll mill to completely disperse the nickel powder and the BaTiO ₃ powder in an organic vehicle to prepare a paste for internal electrodes.

The obtained internal electrode paste was evaluated as described above, and the results are shown in the table. 1 is shown.

According to the results shown in Table 1, the adhesion of Experimental Example 1-1 was ×, and when it was a laminated ceramic capacitor, delamination (interlayer peeling phenomenon) was confirmed in a plurality of samples. On the other hand, in the test examples 1-2 to 1-5, the adhesion evaluation was all Δ or more, and it was confirmed that the occurrence of delamination can be suppressed. In other words, it was confirmed that the adhesion between the internal electrode and the dielectric layer was high in these samples.

Comparing the experimental examples 1-1 to 1-5, it was confirmed that the nickel powder was contained. When the amount is 100 parts by mass, the content of the polyvinyl butyral is 1.0 part by mass or more, and the content of the ethyl cellulose is less than 6.0 parts by mass, whereby the adhesion can be improved. In particular, in Experimental Example 1-3 to Experimental Example 1-5 in which the content of the polyvinyl butyral was 2.0 parts by mass or more, the evaluation of the adhesion was ○ or ◎, and it was confirmed that the adhesion can be particularly improved.

Further, in all of the experimental examples, the dry film density was confirmed to be 4.79 g/ml or more. In particular, the dry film density of Experimental Example 1-1 to Experimental Example 1-4 was 4.80 g/ml or more, and it was confirmed that the dry film density was improved.

Further, in all the experimental examples, it was confirmed that the sheet insult was evaluated as Δ, and a slight sheet intrusion occurred, but the degree did not affect the characteristics of the dielectric layer.

[Experimental Example 2-1 to Experimental Example 2-9]

In the case of the internal electrode paste, the content of each component was as shown in Table 2, and the internal electrode paste was produced and evaluated in the same manner as in Experimental Example 1-1 to Experimental Example 1-5.

Here, Experimental Example 2-1 to Experimental Example 2-9 are examples. Further, the sample of Experimental Example 2-4 was the same as Experimental Example 1-3.

The evaluation results are shown in Table 2.

According to the results shown in Table 2, the adhesion of each of the experimental examples was evaluated as Δ, ○, ◎ One confirmed that the occurrence of delamination can be suppressed. In other words, it was confirmed that the adhesion between the internal electrode and the dielectric layer was high in these samples.

Comparing Experimental Example 2-1 to Experimental Example 2-9, it was confirmed that with internal electricity The improvement of the resin content rate in the paste is also improved, and the evaluation of the sheet damage is also improved. In particular, it was confirmed that the evaluation of Experimental Example 2-3 to Experimental Example 2-9 of 2.8 mass% or more was Δ or ○, and the evaluation of Experimental Example 2-6 to Experimental Example 2-9 of 3.0% by mass or more was ○. In other words, it was confirmed that the improvement in the resin content rate can suppress the sheet from being invaded.

However, it was confirmed that as the content of polyvinyl butyral increased, the density of the dried film decreased. In the case of Experimental Example 2-9 containing 5 parts by mass of polyvinyl butyral, it was confirmed that the dry film density was lowered to 4.74 g/ml.

The inside of the multilayer ceramic capacitor has been described above by the embodiment and the examples. The electrode paste and the laminated ceramic capacitor are not limited to the above-described embodiments and examples. Various modifications and changes can be made without departing from the spirit and scope of the invention.

This application is based on the special wishes submitted to the Japan Patent Office on July 31, 2014. Priority is claimed on No. 157,025, and the entire contents of Japanese Patent Application No. 2014-157025 are incorporated herein by reference.

Claims (5)

A paste for a built-in ceramic capacitor internal electrode, comprising: nickel powder; polyvinyl butyral; and ethyl cellulose. When the content of the nickel powder is 100 parts by mass, the content of the polyvinyl butyral is 1.0 part by mass or more. However, the content of the ethyl cellulose is not more than 6.0 parts by mass, and does not include 3 parts by mass or less, in an amount of not more than 1.0 part by mass and not more than 2.4 parts by mass. The paste for internal electrode of a multilayer ceramic capacitor according to the first aspect of the invention, wherein the content of the polyvinyl butyral and the content of the ethyl cellulose are 0.2 ≦ (polyvinyl butyral content) by mass ratio. The relationship (content of ethyl cellulose). The paste for a multilayer ceramic capacitor internal electrode according to the first aspect of the patent application is applied to a substrate and dried at 120 ° C to have a film density of 4.80 g/ml or more. The paste for a built-in ceramic capacitor internal electrode according to the first aspect of the invention, wherein the total content of the polyvinyl butyral and the content of the ethyl cellulose in the paste for the internal electrode of the multilayer ceramic capacitor is 2.5% by mass or more . A multilayer ceramic capacitor comprising an internal electrode, which is a calcined product of a paste for a multilayer ceramic capacitor internal electrode according to any one of claims 1 to 4.