JP4735071B2 - Electronic component manufacturing method and electronic component - Google Patents

Description

  The present invention relates to an electronic component manufacturing method and an electronic component, and more particularly, an electronic component manufacturing method capable of realizing a thin layered multilayer electronic component such as a multilayer ceramic capacitor, and the manufacturing method thereof. Related electronic components.

  A multilayer ceramic capacitor as an example of an electronic component includes an element body having a multilayer structure in which a plurality of dielectric layers and internal electrode layers are alternately arranged, and a pair of external terminal electrodes formed at both ends of the element body. Composed.

  In this multilayer ceramic capacitor, first, a green sheet that becomes a dielectric layer after firing and an electrode film before firing that becomes an internal electrode layer after firing are alternately laminated in a necessary number to produce a pre-fired element body, Next, after firing this, a pair of external terminal electrodes are formed on both end portions of the element body after firing. The green sheet and the electrode film before firing usually contain a binder. Therefore, the element body before firing is usually fired after heat treatment (binder removal treatment) for removing the binder.

  On the other hand, in recent years, due to miniaturization of various electronic devices, electronic components mounted inside the electronic devices are becoming smaller and higher performance, and the multilayer ceramic capacitor is also required to be smaller and have higher capacity. In order to promote such miniaturization and high capacity, there has been a strong demand for thin dielectric layers and internal electrode layers constituting the multilayer ceramic capacitor, and these thicknesses have recently become several μm or less. I came.

  As the dielectric layer and the internal electrode layer are made thinner, the green sheet and the pre-fired electrode film that form the dielectric layer and the internal electrode layer after firing need to be made thinner. On the other hand, when the green sheet and the electrode film before firing are thinned, there are the following problems. That is, when the green sheet is thinned, there is a problem that structural defects such as pinholes are easily generated and the defect rate is deteriorated. Further, when the electrode film before firing is made thin, the lineability of the internal electrode layer after firing is deteriorated, the electrode coverage is lowered, and as a result, the capacity is lowered.

  Therefore, in order to solve these problems, the density of the green sheet and the electrode film before firing has been increased. However, when the density of the green sheet and the electrode film before firing is increased in this way, there is a problem that cracks are generated in the element body before firing due to the influence of the gas generated during the binder removal process described above. In particular, in addition to increasing the density of the green sheet and the pre-fired electrode film, such a crack problem has become prominent when the number of stacked layers is increased to 100 or more.

  Also, in recent years, a so-called sheet attack that a solvent contained in the internal electrode paste erodes the green sheet when the pre-fired electrode film is formed on the green sheet using the internal electrode paste. In order to prevent this phenomenon, a dry transfer method has been developed (for example, Patent Document 1).

  In this method, first, an electrode film before firing and a blank layer for eliminating a step due to electrode formation are formed on a release layer formed on a support film. Next, an adhesive resin layer (adhesive layer) is formed on another support film, which is transferred onto the pre-fired electrode film and blank layer by thermocompression bonding, and the support film on the adhesive layer side is peeled off. Further, a green sheet is formed on another support film, and this green sheet is transferred onto the adhesive layer on the pre-fired electrode film / margin layer by thermocompression bonding. In this dry transfer method, the release layer, the pre-fired electrode film, the blank layer, the resin layer, and the dielectric layer are sequentially laminated together, so that it is possible to effectively prevent the occurrence of sheet attack.

  However, this dry transfer method has a resin layer as an adhesive layer as compared with a conventional method of directly forming a pre-fired electrode film on a green sheet. For this reason, the amount of resin in the element body before firing increases, and the crack generation rate during the binder removal process described above tends to increase.

JP 2004-303976 A

  The present invention has been made in view of such a situation, and its purpose is to reduce the electrode coverage of the internal electrode layer after firing in the case of downsizing, multilayering, and increasing the capacity of an electronic component such as a multilayer ceramic capacitor. Another object is to provide a method for producing an electronic component that is kept high and has cracks suppressed during binder removal processing, and an electronic component obtained by this production method.

  The present inventors can achieve the above object by controlling the porosity of the pre-fired electrode film, which forms the internal electrode layer after firing, in the production of electronic parts such as multilayer ceramic capacitors. The headline and the present invention have been completed.

That is, the method for manufacturing an electronic component according to the present invention includes:
A method of manufacturing an electronic component having an internal electrode layer,
Preparing a paste for an internal electrode containing a conductor powder, a solvent, and a binder;
Applying the internal electrode paste, then drying, and forming a pre-fired electrode film that will form the internal electrode layer after firing, and
The porosity of the electrode film before firing after drying is set to 5 to 25%.

  In the present invention, the porosity means a volume ratio of voids to the whole electrode film before firing. This porosity is the effective density of the actually formed pre-fired electrode film (ie, the theoretical density calculated from the specific gravity of the components other than the solvent constituting the pre-fired electrode film (ie, non-volatile components) and the blended weight). , Actual density) ratio. Specifically, when the ratio of the effective density to the theoretical density is the filling ratio (filling ratio (%) = effective density / theoretical density × 100), the porosity is the porosity (%) = 100 (%) − Filling rate (%).

In the present invention, it further comprises a step of pressing the pre-fired electrode film,
It is preferable to press so that the weight density per unit volume of the electrode film before firing after pressing is 3 to 20% higher than the weight density per unit volume of the electrode film before firing before pressing.

Alternatively, the method further includes a step of pressing the pre-fired electrode film,
It is preferable to press so that the porosity of the electrode film before firing after pressing is 2 to 20%.

  Improve the electrode coverage of the internal electrode layer after firing by pressing the pre-fired electrode film to improve the weight density by 3-20% or by allowing the porosity to be 2-20% Can be made.

Preferably, the method further includes a step of heating the pre-fired electrode film after pressing to remove a binder contained in the pre-fired electrode film,
The binder is removed so that the porosity of the pre-fired electrode film after removing the binder is 5 to 25%.

  The porosity of the pre-fired electrode film after the binder removal means the porosity after removing components such as the binder removed by the binder removal treatment.

In the present invention, the internal electrode paste preferably further contains an inorganic oxide powder.
More preferably, the internal electrode paste comprises a conductor powder having an average particle size in the range of 0.05 to 0.4 μm and an inorganic oxide powder having an average particle size in the range of 0.002 to 0.1 μm. And the content of the inorganic oxide powder is in the range of 5 to 40 parts by weight with respect to 100 parts by weight of the conductor powder. Such an inorganic oxide powder is added to increase the sintering temperature of the pre-fired electrode film.

  In the manufacturing method of the present invention, it is preferable that the electronic component further includes a dielectric layer in addition to the internal electrode layer. In the case of further having a dielectric layer in addition to the internal electrode layer, the pre-fired electrode film that becomes the internal electrode layer after firing and the green sheet that becomes the dielectric layer after firing are formed by any of the following methods, respectively: It is preferable to do.

  That is, using a dielectric paste, on the support sheet, a green sheet that will form the dielectric layer after firing is formed, and then the internal electrode paste is applied on the green sheet, Then, it is preferable to dry and form the said electrode film before baking. In this method, another green sheet and another pre-fired electrode film are sequentially formed in this order on the pre-fired electrode film, and a plurality of green sheets and a plurality of pre-fired electrode films are formed. It is good also as a structure laminated | stacked alternately. The internal electrode paste may be applied by, for example, a printing method.

  Alternatively, a green sheet that will form the dielectric layer after firing is formed on the first support sheet, the internal electrode paste is applied on the second support sheet, and then dried, It is preferable to form a pre-firing electrode film and transfer the pre-firing electrode film formed on the second support sheet onto the surface of the green sheet formed on the first support sheet. In this method, a plurality of sheets in which the green sheets and the pre-fired electrode films are integrated by transfer are laminated, and a plurality of green sheets and a plurality of pre-fired electrode films are alternately laminated. good. The internal electrode paste may be applied by, for example, a printing method.

  The green sheet is preferably formed so that the thickness of the dielectric layer after firing is 2.5 μm or less. Further, in the green sheet and the electrode film before firing, the ratio of the thickness of the dielectric layer after firing and the thickness of the internal electrode layer after firing is the thickness of the dielectric layer / the thickness of the internal electrode layer = It is preferable to form each so that it may become the range of 0.5-2.0. Thus, when the thickness of the dielectric layer and the internal electrode layer is reduced, the effect of the present invention is particularly increased.

  In the present invention, it is preferable that a plurality of the pre-fired electrode films and a plurality of the green sheets are alternately laminated, and the number of laminated dielectric layers after firing is 100 or more.

In the present invention, the internal electrode paste is applied on a smooth substrate so that the film thickness after drying is 30 to 45 μm, and then blown at a temperature of 100 ° C. for 15 minutes. It is preferable to use an internal electrode paste in which the surface of the resulting coating film has a 60 ° specular gloss (Gs (60 °)) of 100% or more when dried.
Examples of the smooth substrate include a PET film.

  The electronic component according to the present invention can be obtained by any one of the methods described above. Although it does not specifically limit as an electronic component, A multilayer ceramic capacitor, a piezoelectric element, a chip inductor, a chip varistor, a chip thermistor, a chip resistor, and other surface mount (SMD) chip type electronic components are illustrated.

According to the present invention, when manufacturing an electronic component such as a multilayer ceramic capacitor, the thickness of the electronic component is reduced in order to control the porosity of the electrode film before firing, which forms the internal electrode layer after firing, to a predetermined range. Even in this case, it is possible to provide an electronic component in which the generation of cracks during the debinding process is suppressed while the electrode coverage of the internal electrode layer after firing is kept high. In particular, in the present invention, by setting the porosity of the electrode film before firing within a predetermined range, it is possible to effectively ensure the escape path of the binder decomposition gas generated at the time of binder removal.
In the present invention, the electrode coverage refers to the ideal area where the internal electrode layer covers the dielectric layer, assuming that the internal electrode layer has no discontinuity at all. It is the proportion of the area that actually covers the layer.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.
2A and 2B are main part cross-sectional views showing a method for forming a green sheet, an electrode film before firing, and a blank pattern layer according to an embodiment of the present invention,
FIG. 3 (A) is a schematic diagram schematically showing the microstructure of the electrode film before firing of the present invention, FIG. 3 (B) is a schematic diagram schematically showing the microstructure of the conventional electrode film before firing,
4 (A) to 4 (C) and FIGS. 5 (A) to 5 (C) are views showing a method for forming a green sheet, an electrode film before firing, and a blank layer according to another embodiment of the present invention. Sectional view,
6A is a cross-sectional photograph showing an example of a bike removal rack, FIG. 6B is a cross-sectional photograph showing an example of a firing crack,
FIG. 7 is a diagram for explaining a method for measuring the electrode coverage;
8A is a cross-sectional photograph of the pre-firing electrode film according to the example of the present invention, FIG. 8B is a cross-sectional photograph of the pre-firing electrode film according to the comparative example,
9A is a cross-sectional photograph of the element body after firing according to the example of the present invention, and FIG. 9B is a cross-sectional photograph of the element body after firing according to the comparative example.

First, an overall configuration of a multilayer ceramic capacitor will be described as an embodiment of an electronic component manufactured by the method according to the present invention.
As shown in FIG. 1, the multilayer ceramic capacitor 2 according to this embodiment includes a capacitor body 4, a first terminal electrode 6, and a second terminal electrode 8. The capacitor body 4 includes dielectric layers 10 and internal electrode layers 12, and the internal electrode layers 12 are alternately stacked between the dielectric layers 10. One of the internal electrode layers 12 stacked alternately is electrically connected to the inside of the first terminal electrode 6 formed outside the first end of the capacitor element body 4. The other internal electrode layers 12 that are alternately stacked are electrically connected to the inside of the second terminal electrode 8 that is formed outside the second end of the capacitor body 4.

  In the present embodiment, as will be described in detail later, the internal electrode layer 12 forms, on the green sheet 10a, a pre-fired electrode film 12a that will form the internal electrode layer 12 after firing in a predetermined pattern. It is manufactured.

  The material of the dielectric layer 10 is not particularly limited, and is made of a dielectric material such as calcium titanate, strontium titanate and / or barium titanate.

  In this embodiment, the thickness of each dielectric layer 10 is preferably 2.5 μm or less, more preferably 2 μm or less. Furthermore, the ratio of the thickness of the dielectric layer 10 to the thickness of the internal electrode layer 12 (the thickness of the dielectric layer 10 / the thickness of the internal electrode layer 12) is preferably 0.5 to 2.0. In the present embodiment, as will be described later, the pre-firing electrode film 12a shown in FIG. 2B, which will form the internal electrode layer 12 after firing, has a structure having a predetermined porosity. The dielectric layer 10 and the internal electrode layer 12 can be thinned while maintaining a high rate and preventing the occurrence of cracks during binder removal.

  The material of the terminal electrodes 6 and 8 is not particularly limited, but usually copper, copper alloy, nickel, nickel alloy or the like can be used, and silver or silver-palladium alloy can also be used. The thickness of the terminal electrodes 6 and 8 is not particularly limited, but is usually about 10 to 50 μm.

  The shape and size of the multilayer ceramic capacitor 2 may be appropriately determined according to the purpose and application. When the multilayer ceramic capacitor 2 has a rectangular parallelepiped shape, it is usually vertical (0.4 to 5.6 mm, preferably 0.4 to 3.2 mm) × horizontal (0.2 to 5.0 mm, preferably 0.2 to 1.6 mm) × thickness (0.1 to 1.9 mm, preferably 0.1 to 1.6 mm).

Next, an example of a method for manufacturing the multilayer ceramic capacitor 2 according to the present embodiment will be described.
First, a dielectric paste is prepared in order to manufacture a ceramic green sheet that will form the dielectric layer 10 shown in FIG. 1 after firing.
The dielectric paste is generally composed of an organic solvent-based paste or an aqueous paste obtained by kneading ceramic powder and an organic vehicle.

  The ceramic powder can be appropriately selected from various compounds to be complex oxides and oxides, such as carbonates, nitrates, hydroxides, organometallic compounds, and the like, and can be used as a mixture. The ceramic powder is usually used as a powder having an average particle size of 0.3 μm or less, preferably 0.2 μm or less. In order to form a very thin green sheet, it is desirable to use a powder finer than the thickness of the green sheet.

  An organic vehicle is obtained by dissolving a binder in an organic solvent. The binder used for the organic vehicle is not particularly limited, and examples thereof include various usual binders such as ethyl cellulose, polyvinyl butyral, and acrylic resin.

  Also, the organic solvent used in the organic vehicle is not particularly limited, and usual organic solvents such as alcohol, acetone, methyl ethyl ketone (MEK), toluene, xylene, ethyl acetate, butyl stearate, terpineol, butyl carbitol, isobornyl acetate, etc. Is exemplified.

  Further, the vehicle in the aqueous paste is obtained by dissolving a water-soluble binder in water. The water-soluble binder is not particularly limited, and polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, water-soluble acrylic resin, emulsion and the like are used. The content of each component in the dielectric paste is not particularly limited, and the normal content, for example, the binder may be about 1 to 5% by mass, and the solvent (or water) may be about 10 to 50% by mass.

  The dielectric paste may contain additives selected from various dispersants, plasticizers, dielectrics, glass frit, insulators, charging aids, and the like as necessary. However, the total content of these is preferably 10% by mass or less. Examples of the plasticizer include phthalate esters such as dioctyl phthalate and benzylbutyl phthalate, adipic acid, phosphate esters, glycols, and the like. When a butyral resin is used as the binder resin, the plasticizer preferably has a content of 25 to 100 parts by mass with respect to 100 parts by mass of the binder resin. If the amount of the plasticizer is too small, the green sheet tends to be brittle. If the amount is too large, the plasticizer oozes out and is difficult to handle.

  Then, using this dielectric paste, it is preferably 3 μm or less, more preferably 2.5 μm or less on the carrier sheet 20 as the first support sheet as shown in FIG. The green sheet 10a is formed with a thickness of. By forming the green sheet 10a with such a thickness, the thickness of the dielectric layer 10 after firing can be reduced to preferably 2.5 μm or less, more preferably 2 μm or less.

  The green sheet 10a is formed on the carrier sheet 20 and then dried. The drying temperature of the green sheet 10a is preferably 50 to 100 ° C., and the drying time is preferably 1 to 20 minutes. The thickness of the green sheet 10a after drying shrinks to a thickness of 5 to 25% as compared with that before drying.

  As the carrier sheet 20, for example, a PET film or the like is used, and a film coated with silicon or the like is preferable in order to improve peelability. Although the thickness of these carrier sheets 20 is not specifically limited, Preferably, it is 5-100 micrometers.

  Next, as shown in FIG. 2 (B), a pre-fired electrode film 12a having a predetermined pattern is formed on the surface of the green sheet 10a formed on the carrier sheet 20, and the pre-fired electrode film 12a is formed before and after that. A blank pattern layer 22 having substantially the same thickness as the pre-firing electrode film 12a is formed on the surface of the green sheet 10a that has not been formed. The thickness of the pre-firing electrode film 12a is preferably 2 μm or less, more preferably 1.5 μm or less. By forming the pre-firing electrode film 12a with such a thickness, the thickness of the internal electrode layer 12 after firing can be set to a desired thickness.

  The pre-fired electrode film 12a is preferably formed on the surface of the green sheet 10a by a thick film forming method such as a printing method using an internal electrode paste. When the pre-firing electrode film 12a is formed on the surface of the green sheet 10a by a screen printing method or a gravure printing method, which is one of the thick film methods, it is performed as follows.

  First, an internal electrode paste is prepared. The internal electrode paste is prepared by kneading a conductor powder, an inorganic oxide powder as a co-material, and an organic vehicle.

  Although it does not specifically limit as conductor powder, It is preferable to comprise at least 1 sort (s) chosen from Cu, Ni, and these alloys, More preferably, it comprises Ni or Ni alloy, and also these mixtures. .

  Ni or Ni alloy includes at least one element selected from Mn, Cr, Co and Al, or at least one element selected from Pt, Re, Rh, Ru, Ir, Os and W and Ni. An alloy is preferable, and the Ni content in the alloy is preferably 80 mol% or more. In addition, in Ni or Ni alloy, various trace components, such as P, Fe, and Mg, may be contained about 0.1 wt% or less.

  Such a conductor powder is not particularly limited in its shape, such as spherical or flake shaped, and may be a mixture of these shapes. It is preferred to use body powder. As the conductor powder, one having an average particle diameter of preferably 0.05 to 0.4 μm, more preferably 0.05 to 0.2 μm is used. When a conductor powder having a large average particle diameter is used, it is difficult to reduce the thickness of the electrode film 12a before firing, and as a result, it is difficult to reduce the thickness of the internal electrode layer 12 after firing. On the other hand, if a conductor powder having a small average particle diameter is used, handling becomes difficult. The conductive powder is preferably contained in an amount of 35 to 70% by weight, more preferably 40 to 55% by weight, based on the entire internal electrode paste.

  In the internal electrode paste, inorganic oxide powder is included as a co-material. As such an inorganic oxide powder, a ceramic powder having the same composition as the ceramic powder contained in the green sheet 10a is preferable. The common material has an effect of suppressing sintering of the conductor powder in the firing process. As the inorganic oxide powder used as the co-material, one having an average particle diameter of preferably 0.002 to 0.2 μm, more preferably 0.005 to 0.1 μm is used. In the present embodiment, by setting the average particle diameter of the conductor powder and the average particle diameter of the common material within the predetermined ranges, the pre-firing electrode film 12a can be thinned, and the conductor The powder and the common material can be favorably dispersed.

  The content of the inorganic oxide powder as the co-material in the internal electrode paste is preferably 5 to 40 parts by weight, and more preferably 5 to 30 parts by weight with respect to 100 parts by weight of the conductor powder. If the content of the co-material is too small, the sintering of the internal electrode starts from a low temperature, and the difference in sintering temperature between the internal electrode layer 12 and the dielectric layer 10 becomes large, so that a firing crack occurs. . On the other hand, when there is too much content of a common material, the electrode coverage of the internal electrode layer 12 will fall.

  The organic vehicle contains a binder and a solvent. Examples of the binder include, but are not limited to, ethyl cellulose, acrylic resin, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyolefin, polyurethane, polystyrene, or a copolymer thereof. Among these, ethyl cellulose, Polyvinyl butyral and polyvinyl acetal are preferably used. The binder is preferably contained in an amount of 2 to 6 parts by weight with respect to 100 parts by weight of the conductor powder.

  Examples of the solvent include, but are not limited to, terpineol, butyl carbitol, kerosene, acetone, isobonyl acetate, and the like. In this embodiment, terpineol, dihydroterpineol, terpineol acetate, or dihydroterpineol acetate is particularly used. The solvent is preferably contained in the internal electrode paste at 20 to 60% by weight, more preferably 25 to 55% by weight.

  The internal electrode paste preferably contains a plasticizer or a pressure-sensitive adhesive for the purpose of improving the adhesion to the green sheet. Examples of the plasticizer include phthalic acid ester, adipic acid, phosphoric acid ester, glycols and the like. The plasticizer is preferably contained in an amount of 10 to 300 parts by weight, more preferably 10 to 150 parts by weight, with respect to 100 parts by weight of the binder in the organic vehicle. If the content of the plasticizer is too small, there is no effect of addition, and if it is too large, the strength of the pre-fired electrode film 12a is remarkably lowered, and excessive plasticizer tends to ooze out from the pre-fired electrode film 12a.

  Furthermore, the internal electrode paste preferably contains a dispersant for the purpose of improving the dispersibility of the conductor powder and the co-material and improving the stability (change with time) of the paint. Examples of the dispersant include, but are not limited to, polyethylene glycol dispersants, polycarboxylic acid dispersants, polyhydric alcohol partial ester dispersants, ester dispersants, ether dispersants, and the like. In addition, there are block polymer type dispersants and graft polymer type dispersants. The dispersant is preferably contained in an amount of 0.1 to 5 parts by weight with respect to 100 parts by weight of the conductor powder. When the content of the dispersant is too small, the effect of addition becomes insufficient, and when the content is too large, there may be a disadvantage that the dispersibility is lowered due to micelle formation or reaggregation.

  The internal electrode paste can be formed by mixing the above-mentioned components with a ball mill, a three-roll mill, or the like to form a slurry.

  Then, using this internal electrode paste, an electrode paste film having a predetermined pattern is formed by a printing method, and then dried to form a pre-firing electrode film 12a. Drying is performed to remove volatile components such as a solvent contained in the electrode paste film. The drying temperature is not particularly limited, but is preferably 70 to 120 ° C., and the drying time is preferably 1 to 15 minutes.

  In this embodiment, the electrode film 12a before firing obtained by applying the internal electrode paste by a printing method and then drying it has a structure having a predetermined gap as shown in FIG. That is, in the pre-firing electrode film 12a of this embodiment, as shown in FIG. 3A, the conductor powder 120 and the common material (inorganic oxide powder) 122 are dispersed in an organic nonvolatile component 124 such as a binder. And a structure having a plurality of predetermined gaps 126. The present embodiment has the greatest feature in that the pre-fired electrode film 12a has a structure having a predetermined gap 126, and by having such a structure, the pre-fired electrode film 12a (that is, the pre-fired electrode film 12a (ie, Even when the internal electrode layer 12) after firing is thinned, the generation of cracks during the binder removal process can be effectively prevented, and the electrode coverage of the internal electrode layer 12 after firing is increased. be able to.

  Specifically, the void ratio when the ratio of the voids 126 to the whole pre-firing electrode film 12a is expressed as a volume ratio is 5 to 25%, preferably 5 to 20%. The porosity was actually formed with respect to the theoretical density calculated from the specific gravity and blending weight of the conductive powder 120, the co-material (inorganic oxide powder) 122, and the organic non-volatile component 124 constituting the electrode film 12a before firing. It can be calculated from the ratio of the effective density of the pre-firing electrode film 12a. Specifically, when the ratio of the effective density to the theoretical density is the filling ratio (filling ratio (%) = effective density / theoretical density × 100), the porosity is the porosity (%) = 100 (%) − It can be determined by the filling rate (%). If the porosity is too low, the rate of occurrence of cracks during binder removal processing is increased. On the other hand, if the porosity is too high, the electrode coverage of the internal electrode layer 12 after firing tends to decrease. The organic non-volatile component 124 includes components other than the solvent removed under the above drying conditions such as a binder, a plasticizer, an adhesive, and a dispersant.

  In particular, in the present embodiment, by setting the porosity of the electrode film 12a before firing after drying within the above range, the electrode coverage of the internal electrode layer 12 after firing is increased by a press before firing. Even when the porosity of the electrode film 12a is lowered, a sufficient escape path for the binder decomposition gas generated during the binder removal can be ensured.

  Conventionally, the electrode film 12a 'before firing after coating and drying has a structure substantially free of voids as shown in FIG. In this conventional pre-fired electrode film 12a ', the packing density of the pre-fired electrode film 12a' is improved in order to keep the electrode coverage of the internal electrode layer after fired high. Specifically, as shown in FIG. 3B, the gap between the conductor powder 120 'and the common material 122' is made as small as possible. However, in the case of such a structure, it is possible to increase the electrode coverage by improving the packing density of the pre-fired electrode film 12a ′, while avoiding the escape route of the binder decomposition gas generated during the debinding process. As a result, there is a problem that cracks (debike racks) are generated. Furthermore, in this conventional pre-fired electrode film 12a ′, the common material 122 ′ is aggregated, the structure surrounding the conductor powder 120 ′ is broken, and the sintering suppressing effect due to the addition of the common material 122 ′ is ineffective. There is also a problem that the sintering temperature of the electrode film 12a ′ is lowered and cracks (firing cracks) are generated during firing.

  On the other hand, in this embodiment, since the porosity of the pre-firing electrode film 12a is within the predetermined range, these problems can be effectively solved.

  In the present embodiment, examples of the method for setting the porosity of the pre-fired electrode film 12a within the predetermined range include a kneading method for kneading the internal electrode paste and a blending composition for preparing the internal electrode paste. Examples thereof include a method of adjusting, and a method of adjusting the amount of a dispersant added when producing the internal electrode paste. In particular, in the present embodiment, it is preferable to uniformly disperse the conductor powder 120 and the common material 122 contained in the internal electrode paste by the above methods. Thus, by uniformly dispersing the conductor powder 120 and the common material 122, when the pre-firing electrode film 12a is formed, it is possible to effectively prevent these powders from being closely packed. A fine and uniform void can be formed inside the pre-fired electrode film 12a. Furthermore, by uniformly dispersing the conductor powder 120 and the common material 122, the effect of adding the common material can be sufficiently exhibited, and as a result, firing cracks can be prevented.

  In the internal electrode paste used in the present embodiment as described above, since the conductive powder 120 and the common material 122 are uniformly dispersed, for example, a coating obtained by using this internal electrode paste. The film will have high smoothness. Specifically, such an internal electrode paste is applied on a PET film with a Gap 250 μm applicator so that the film thickness after drying is 30 to 45 μm, and then at 100 ° C. for 15 minutes. When dried with a blower-type dryer, the 60 ° specular gloss (Gs (60 °)) of the surface of the obtained coating film can be preferably 100% or more. The 60-degree specular gloss can be measured by the measurement method 3 in “Specular Gloss Measurement Method” of JIS Z 8741.

  Further, as shown in FIG. 2 (B), the blank pattern layer 22 is formed on the green sheet 10a after the electrode film 12a having a predetermined pattern is formed by a printing method, or before that. On the green sheet 10a on which no is formed, it is formed with substantially the same thickness as the pre-firing electrode film 12a. The blank pattern layer 22 is made of the same material as that of the green sheet 10a described above. Further, the blank pattern layer 22 can be formed by the same method as the electrode film 12a before firing or the green sheet 10a described above.

  Next, by laminating a plurality of sheets consisting of the green sheet 10a, the pre-firing electrode film 12a, and the blank pattern layer 22 shown in FIG. 2B, the green sheet 10a, the pre-firing electrode film 12a, and the blank pattern layer 22, A laminate before firing in which a plurality of layers are stacked is obtained. In addition, as a method of obtaining a laminate before firing, in addition to a method of laminating a plurality of sheets including the green sheet 10a, the pre-fired electrode film 12a, and the blank pattern layer 22 shown in FIG. And a method of forming another green sheet 10a, the pre-fired electrode film 12a, and the blank pattern layer 22 one after another on the pre-fired electrode film 12a and the blank pattern layer 22 shown in FIG.

Next, an outer layer green sheet having a thickness of about 15 μm is laminated on the upper and lower surfaces of the laminate obtained above, and then pressed to obtain a laminate after pressing. In this embodiment, it is preferable to press so that the electrode film 12a before baking in the laminated body after a press may become the following ranges. That is, the weight density per unit volume (g / cm ³ ) of the electrode film 12a before firing after pressing is compared with the weight density (g / cm ³ ) per unit volume of the electrode film 12a before firing before pressing. It is preferable to press so as to improve 3 to 20%. Or it is preferable to press so that the porosity of the electrode film 12a before baking after pressing may be 2 to 20%. In the present embodiment, by pressing the pre-fired electrode film 12a after the press within the predetermined range, a sufficient escape path for the binder decomposition gas generated at the time of the binder removal is obtained (that is, the motorcycle rack is removed). The electrode coverage of the internal electrode layer 12 after firing can be improved.

In this embodiment, the laminate is pressed at a pressure of 0.1 to 10 t / cm ² , a pressing temperature of 60 to 150 ° C., and a pressing time of 6 seconds so that the pre-fired electrode film 12a after pressing is in the above range. It is preferable to press under a condition of ˜60 minutes.

  Next, the pressed laminate is cut into a predetermined size to form a green chip, and then the binder removal process is performed on the green chip.

  In the present embodiment, the binder removal treatment is performed so that the porosity of the pre-fired electrode film 12a in the green chip after the binder removal treatment is 5 to 25%, preferably 5 to 20%.

As specific binder removal treatment conditions, the heating rate is 5 to 300 ° C./hour, particularly 5 to 50 ° C./hour, the holding temperature is 200 to 700 ° C., particularly 300 to 650 ° C., the holding time is 0.5 to It is preferable to use a mixed gas of N ₂ and H ₂ in an atmosphere: humidified for 20 hours, particularly 1 to 10 hours.

Next, the green chip subjected to the binder removal treatment is subjected to firing and heat treatment.
Firing is performed at a heating rate of 50 to 500 ° C./hour, particularly 200 to 300 ° C./hour, a holding temperature of 1100 to 1300 ° C., particularly 1150 to 1250 ° C., a holding time of 0.5 to 8 hours, particularly 1 to 3 Time, cooling rate: 50 to 500 ° C./hour, particularly 200 to 300 ° C./hour, atmospheric gas: It is preferable to use conditions such as a mixed gas of humidified N ₂ and H ₂ .

However, the oxygen partial pressure in the atmosphere during firing is preferably 10 ⁻² Pa or less, particularly preferably 10 ⁻² to 10 ⁻⁸ Pa. If the above range is exceeded, the internal electrode layer tends to oxidize, and if the oxygen partial pressure is too low, the electrode material of the internal electrode layer tends to abnormally sinter and tend to break.

The heat treatment (annealing) after such firing is preferably performed at a holding temperature or a maximum temperature of 900 ° C. or higher, more preferably 1000 to 1100 ° C. If the holding temperature or maximum temperature during heat treatment is less than the above range, the dielectric material is insufficiently oxidized and the insulation resistance life tends to be shortened. In addition to a decrease, it tends to react with the dielectric substrate and shorten its lifetime. The oxygen partial pressure during the heat treatment is higher than the reducing atmosphere during firing, and is preferably 10 ⁻³ Pa to 1 Pa, more preferably 10 ⁻² Pa to 1 Pa. Below the range, it is difficult to re-oxidize the dielectric layer 10, and when the range is exceeded, the internal electrode layer 12 tends to oxidize.

As other heat treatment conditions, holding time: 0 to 6 hours, particularly 2 to 5 hours, cooling rate: 50 to 500 ° C./hour, particularly 100 to 300 ° C./hour, gas for atmosphere: humidified N ₂ gas Etc. are preferable.

Note that to wet the N ₂ gas and mixed gas, etc., through a gas, for example, water heated, may be used to bubbling to device. In this case, the water temperature is preferably about 0 to 75 ° C. The binder removal treatment, firing and heat treatment may be performed continuously or independently. When performing these continuously, after removing the binder, the atmosphere is changed without cooling, and then the temperature is raised to the holding temperature at the time of baking to perform baking, and then cooled to reach the heat treatment holding temperature. Sometimes it is preferable to perform heat treatment by changing the atmosphere. On the other hand, when performing these independently, at the time of firing may be carried out in a mixed gas atmosphere of N ₂ and H ₂ in a wet the entire process of firing, N ₂ gas or to the holding temperature of the binder removal process After raising the temperature in a humidified N ₂ gas atmosphere, the atmosphere may be changed and the temperature may be further increased. After cooling to the holding temperature at the time of heat treatment, the N ₂ gas or humidified N ₂ gas atmosphere is changed again. You may change and continue cooling. In the heat treatment, the entire heat treatment process may be a humidified N ₂ gas atmosphere, or the temperature may be changed to a holding temperature in the N ₂ gas atmosphere and then the atmosphere may be changed.

The sintered body (element body 4) thus obtained is subjected to end surface polishing by, for example, barrel polishing, sand plast, etc., and terminal electrode paste 6 is baked to form terminal electrodes 6 and 8. The firing conditions for the terminal electrode paste are preferably, for example, about 10 minutes to 1 hour at 600 to 800 ° C. in a humidified mixed gas of N ₂ and H ₂ . Then, if necessary, a pad layer is formed on the terminal electrodes 6 and 8 by plating or the like. In addition, what is necessary is just to prepare the paste for terminal electrodes like the above-mentioned electrode paste.
The multilayer ceramic capacitor of the present invention thus manufactured is mounted on a printed circuit board by soldering or the like and used for various electronic devices.

The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.
For example, the method of the present invention can be applied not only to a method for manufacturing a multilayer ceramic capacitor but also to a method for manufacturing other electronic components.

  In the embodiment described above, the pre-firing electrode film 12a and the blank pattern layer 22 are formed directly on the green sheet 10a by a printing method. For example, the electrode film 12a and the blank pattern layer 22 are formed by a transfer method as shown in FIGS. May be.

  That is, in this transfer method, as shown in FIG. 4A, first, a release layer 26 is formed on a carrier sheet (second support sheet) 24, and then an electrode film before firing is formed on the release layer 26. 12a and a blank pattern layer 22 are formed. The release layer 26 contains ceramic particles, a binder, a plasticizer, and a release agent as an optional component, and usually has a thickness of 0.02 to 0.2 μm. The pre-firing electrode film 12a and the blank pattern layer 22 can be formed by the same method as described above.

  On the other hand, an adhesive layer 30 is formed on a carrier sheet (third support sheet) 28 different from this. The adhesive layer 30 includes a binder and a plasticizer, and usually has a thickness of 0.01 to 0.3 μm.

  Then, as shown in FIGS. 4B and 4C, the adhesive layer 30 is pressed onto the pre-fired electrode film 12a and the blank pattern layer 22, and subsequently, the carrier on which the adhesive layer 30 is formed. The sheet 28 is peeled off, and the adhesive layer 30 is formed on the surfaces of the pre-fired electrode film 12 a and the blank pattern layer 22.

  Next, as shown in FIG. 5A, a green sheet 10a is formed on another carrier sheet (first support sheet) 20 in the same manner as described above. Then, the green sheet 10 a formed on the carrier sheet 20 is pressed against the adhesive layer 30 formed on the surfaces of the pre-firing electrode film 12 a and the blank pattern layer 22. Then, the carrier sheet 20 on which the green sheet 10 a has been formed is peeled off, and the green sheet 10 a is formed on the pre-fired electrode film 12 a and the blank pattern layer 22 via the adhesive layer 30.

  Then, a plurality of sheets made of the pre-firing electrode film 12a, the blank pattern layer 22 and the green sheet 10a obtained in this manner can be laminated to form a laminated body before firing. According to such a transfer method, dry lamination is possible, so that erosion (sheet attack phenomenon) of the green sheet 10a due to penetration of the organic solvent into the green sheet 10a can be effectively prevented.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

Example 1
The following dielectric paste and internal electrode paste were prepared.

Dielectric paste First, BaTiO ₃ powder (BT-02 / Sakai Chemical Industry Co., Ltd.), MgCO ₃ , MnCO ₃ , (Ba _0.6 Ca _0.4 ) SiO ₃ and rare earth (Gd ₂ O ₃ , Tb ₄ O ₇ , Dy ₂ O ₃ , Ho ₂ O ₃ , Er ₂ O ₃ , Tm ₂ O ₃ , Yb ₂ O ₃ , Lu ₂ O ₃ , Y ₂ O ₃ ). Next, these raw material powders were wet mixed by a ball mill for 16 hours and dried to obtain a dielectric material. These raw material powders had an average particle size of 0.1 to 1 μm. (Ba _0.6 Ca _0.4 ) SiO ₃ was obtained by wet-mixing BaCO ₃ , CaCO ₃ and SiO ₂ with a ball mill for 16 hours, and firing in air at 1150 ° C. after drying using a ball mill. It was produced by wet milling for a period of time.

  Next, in order to make the obtained dielectric material into a paste, an organic vehicle was added to the dielectric material and mixed with a ball mill to obtain a dielectric paste. The organic vehicle is based on 100 parts by weight of the dielectric material, polyvinyl butyral: 6 parts by weight as a binder, bis (2-ethylhexyl) phthalate (DOP): 3 parts by weight, ethanol: 85 parts by weight, toluene: 15 The blending ratio of parts by mass was used.

Internal electrode paste First, Ni powder with an average particle diameter of 0.2 μm: 100 parts by weight as a conductor powder, Ceramic powder with an average particle diameter of 0.05 μm as a co-material: 20 parts by weight, Ethyl cellulose resin as a binder : 4.5 parts by weight, fatty acid ester dispersant as dispersant: 1 part by weight, and terpineol as solvent : 75 parts by weight were prepared. In addition, as said ceramic powder, what has the composition similar to the dielectric material contained in the dielectric paste was used.

Next, the raw material prepared above was kneaded with three rolls and slurried to obtain an internal electrode paste. In this example, as shown in Table 1, internal electrode pastes with different kneading conditions were prepared by changing the number of passes of the three rolls within a range of 1 to 100 times. In addition, the internal electrode paste of this example had a theoretical density calculated from each raw material excluding the volatile component terpineol was 6.33 g / cm ³ . The theoretical density was calculated from the density of each raw material and the blending amount of each raw material.

Pre-firing electrode film sample Next, the internal electrode paste obtained above was used to produce the pre-firing electrode film shown below, and firing in each step of the coating / drying step, pressing step, and debinding step The properties of the front electrode film were evaluated.

Application / Drying Step First, the internal electrode pastes produced in the above-mentioned different kneading times are applied onto a PET film with a Gap 250 μm applicator, and then dried in a blow dryer at 100 ° C. for 15 minutes. As a result, an electrode film before firing after coating and drying was obtained. In this example, the electrode film before firing was formed so that the film thickness after drying was 30 to 45 μm. Then, the density of each pre-firing electrode film after application / drying was calculated from the volume of each obtained pre-firing electrode film (= electrode film formation area × electrode film thickness) and weight, and obtained. From the density after coating and drying and the theoretical density (6.33 g / cm ³ ), the porosity after coating and drying of each pre-fired electrode film was calculated. The results are shown in Table 1.

  Moreover, about each obtained electrode film before baking, using Nippon Denshoku Industries Co., Ltd. VGS-1D, according to JIS Z-8741 (1983) method 3, 60 degree specular glossiness (Gs (60 degrees)) ) Was measured. The results are shown in Table 1. The greater the gloss%, the better the surface smoothness.

Pressing process Next, for each pre-fired electrode film obtained after coating and drying obtained above, pressing is performed under the conditions of pressing temperature: 120 ° C., pressing pressure: 1 t / cm ² , pressing time: 10 minutes, An electrode film before firing after pressing was obtained. Then, the density of each pre-fired electrode film after pressing is calculated from the volume (= electrode film formation area × electrode film thickness) and weight of each pre-fired electrode film after pressing, and the obtained post-pressing And the density before pressing (= density after coating and drying), the density improvement rate after pressing of each pre-firing electrode film was calculated. Further, the porosity after pressing of each pre-fired electrode film was calculated from the density after pressing and the theoretical density (6.33 g / cm ³ ).

The porosity of the binder removal step debinding step, the specific gravity of the non-volatile organic components removed by binder removal processing as is almost 1, the porosity after pressing (%), non-volatile organic components removed by debinding This was calculated by adding the weight ratio (wt%).

Multilayer Ceramic Capacitor Sample Next, using the dielectric paste and internal electrode paste obtained above, a multilayer ceramic capacitor sample was manufactured, and the crack occurrence rate after debinding (debike rack rate), after firing The crack generation rate (firing crack rate) and the electrode coverage of the internal electrode layer were each evaluated. The multilayer ceramic capacitor sample was manufactured by the following method.

  That is, first, the green sheet 10a shown in FIG. 2A was formed using the dielectric paste obtained above. Next, as shown in FIG. 2B, a pre-firing electrode film 12a and a blank pattern layer 22 having the same thickness as the pre-firing electrode film 12a were formed by a printing method. In addition, the electrode film 12a before baking was formed using the paste for internal electrodes which each differed in the kneading | mixing conditions obtained above. The blank pattern layer 22 was formed using the dielectric paste obtained above.

  Next, another green sheet 10a is formed on the pre-fired electrode film 12a and the blank pattern layer 22 shown in FIG. 2B, and then another pre-fired electrode film 12a and a blank are formed on the green sheet 10a. A layered product was obtained by forming the pattern layer 22 and forming them one after another. In this example, the thickness of the green sheet 10a was 2.6 μm, and the thickness of the pre-firing electrode film 12a and the blank pattern layer 22 was 1.3 μm.

Next, green sheets for outer layers were laminated on the upper and lower surfaces of the obtained laminate, and then the laminate was pressed to obtain a pressed laminate. The press conditions were as follows: press temperature: 120 ° C., press pressure: 1 t / cm ² , press time: 10 minutes.

  Next, the obtained laminated body after pressing was cut into a predetermined size and subjected to binder removal processing, firing and annealing (heat treatment) to produce a chip-shaped sintered body.

The binder removal was performed at a rate of temperature increase of 15 to 50 ° C./hour, a holding temperature of 600 ° C., a holding time of 2 hours, an atmospheric gas: a mixed gas of N ₂ and H ₂ that was humidified (PO ₂ = 10 ⁻¹⁹ Pa), I went there. Firing is performed at a temperature rising rate of 200 to 300 ° C./hour, a holding temperature of 1200 ° C., a holding time of 2 hours, a cooling rate of 300 ° C./hour, an atmospheric gas: a mixed gas of humidified N ₂ and H ₂ , oxygen content The pressure was 10 ⁻⁷ Pa. Annealing (reoxidation) is performed at a heating rate of 200 to 300 ° C./hour, a holding temperature of 1050 ° C., a holding time of 2 hours, a cooling rate of 300 ° C./hour, an atmosphere gas: humidified N ₂ gas, and an oxygen partial pressure. : 10 ⁻¹ Pa. Note that a wetter was used for humidifying the atmospheric gas during binder removal, firing, and annealing.

Next, after polishing the end face of the chip-shaped sintered body by sand blasting, the external electrode paste is transferred to the end face and baked at 800 ° C. for 10 minutes in a humidified N ₂ + H ₂ atmosphere. Thus, a multilayer ceramic capacitor sample having the configuration shown in FIG. 1 was obtained. In this example, the capacitor samples of Samples 1 to 7 shown in Table 1 were manufactured using the internal electrode pastes having different kneading conditions prepared above.

  The size of each sample thus obtained is 2.0 mm × 1.2 mm × 0.9 mm, the number of dielectric layers sandwiched between internal electrode layers is 250, and the thickness is 1.8 μm. The thickness of the internal electrode layer was 1.0 μm.

  Next, for each of the obtained capacitor samples, the crack occurrence rate at the time of binder removal (debike rack rate), the crack occurrence rate at firing (fired crack rate), and the electrode coverage of the internal electrode layer were evaluated.

  As shown in FIG. 6 (A), cracks (debike racks) that occur at the time of binder removal are characterized by entering significantly along the laminate surface of the laminate. Therefore, the case where such a crack occurred was regarded as a bike removal rack, and the bike removal rack occurrence rate (bike removal rack rate) of each sample was calculated. A lower bike rack rate is preferable. The results are shown in Table 1.

  On the other hand, cracks that occur during firing (firing cracks) are caused by the difference in sintering behavior between the internal electrode layer and the dielectric layer, and as shown in FIG. In addition, it is characterized by being relatively small compared to a bike rack. Therefore, the case where such a crack occurred was regarded as a firing crack, and the firing crack occurrence rate (firing crack rate) of each sample was calculated. A lower firing crack rate is preferred. The results are shown in Table 1.

The coverage of the internal electrode layer was measured by measuring a metal microscope image on the cut surface of the capacitor element.
First, each capacitor sample was cut along a plane perpendicular to the stacking direction, and the cut surface was polished. And the electrode coverage of the internal electrode layer was calculated | required from the metal micrograph of the grinding | polishing surface. As shown in FIG. 7, when cut along a plane perpendicular to the stacking direction, the internal electrodes are observed as line segments, and the holes on the electrode surfaces are observed as discontinuities in the line segments. The actual length of the electrode segment was measured, and the ratio of the length of the electrode segment to the visual field length was defined as the electrode coverage (%). Specifically, the total length of the electrode line segments shown in FIG. 7 (that is, the length obtained by removing the discontinuity from the visual field length) is obtained, and the ratio of the total length of the electrode line segments to the visual field length Was obtained by calculating. In addition, the electrode coverage was calculated | required by measuring about 170 micrometers of visual field length and 10 electrode line segments (a total of 40 lines) using 4 metal micrographs. The results are shown in Table 1.

  Table 1 shows the evaluation results of the pre-fired electrode film sample and the capacitor sample, which were manufactured using the internal electrode pastes having different kneading states obtained by changing the number of passes to the three rolls, respectively.

  From Table 1, the porosity after coating and drying is 5 to 25%, the density improvement rate after pressing is 3 to 20%, the porosity after pressing is 2 to 20%, and the porosity after debinding is 5 to 20%. Samples 2 to 5 in which the percentages were% showed that the bike removal rack ratio and the firing crack ratio were 0 ppm, and the electrode coverage of the internal electrode layer exceeded 80%, which was a good result. Moreover, it was also confirmed that Samples 2 to 5 of these Examples all had excellent surface smoothness with the glossiness of the electrode film before firing after coating and drying being 100% or more.

  On the other hand, the sample of Comparative Example 1 in which the porosity after coating / drying was as high as 30% was as high as 21% for the porosity after pressing and 26% after the binder removal, resulting in firing. The electrode coverage of the subsequent internal electrode layer was as low as 60%, resulting in insufficient capacity as a capacitor. Furthermore, this sample 1 also resulted in low gloss after coating and drying.

  Moreover, the samples 6 and 7 of the comparative examples in which the porosity after coating and drying was lowered to 4% and 1%, respectively, also decreased the porosity after pressing to 1.8% and 1%. There was a tendency for the firing crack rate to deteriorate. In these samples, the cause of the deterioration of the bike rack removal rate was that the void ratio after pressing was lowered, so that the crack of the binder decomposition gas generated during the binder removal process could not be secured, and cracks occurred. Conceivable. In addition, as a cause of the deterioration of the firing crack rate, since the filling of Ni progressed in the electrode film before firing, the common material goes out from between Ni, and Ni contacts each other. This is probably because the sintering temperature is lowered. Furthermore, in these samples 6 and 7, the glossiness after coating and drying was also lowered.

  8A shows a cross-sectional photograph of the electrode film before firing of the sample (sample 3) of the example after pressing, and FIG. 8B shows the firing of the sample of the comparative example (sample 7) after pressing. Cross-sectional photographs of the front electrode film are shown respectively. From FIG. 8A, it can be confirmed that in the sample of the example, there are a plurality of voids and the Ni powder and the common material are uniformly dispersed. Further, from FIG. 8B, in the sample of the comparative example, the common material goes out from between the Ni powders and is distributed in an aggregated state near the interface between the electrode film before firing and the green sheet. Can be confirmed.

  FIG. 9A shows a cross-sectional photograph of the element body after firing the sample of the example (sample 4), and FIG. 9B shows a cross-sectional photograph of the element body after firing of the sample of the comparative example (sample 1). Are shown respectively. From FIG. 9A, in the sample of the example, the internal electrode layer has a good line property, whereas in the sample of the comparative example, many electrode breaks occur and the line property is poor. I can confirm.

  In this example, as an example of a method for adjusting the porosity of the electrode before firing after coating and drying, a method of changing the number of passes of the three rolls when manufacturing the internal electrode paste is illustrated. It is also possible to adjust the porosity by changing other methods, for example, the blending ratio of the internal electrode paste and the amount of the dispersant.

Example 2
Except for changing the pressing conditions to the conditions shown in Table 2, the pre-fired electrode film sample and the multilayer ceramic capacitor sample according to Samples 8 to 12 were replaced with Sample 5 of Example 1 in the same manner as Sample 2 of Example 1. In the same manner as described above, a pre-firing electrode film sample and a multilayer ceramic capacitor sample according to Sample 13 were produced.

  Table 2 shows the evaluation results of the pre-firing electrode film sample and the capacitor sample when the pressing conditions in the pressing process are changed. In Table 2, Samples 2 and 5 are the same samples as Samples 2 and 5 of Example 1.

  From Table 2, even when the press conditions were changed to change the density improvement rate after pressing and the porosity after pressing, the density improvement rate after pressing was 3 to 20%, and the porosity after pressing was 2 Samples 2, 9, and 10 in the examples of -20% had a bike removal rack ratio and a firing crack ratio of 0 ppm, and the electrode coverage of the internal electrode layer exceeded 80%. became.

  On the other hand, the samples 8, 11 and 12 of the reference examples in which the density improvement rate after pressing was less than 3% and the porosity after pressing was more than 20% were all low in electrode coverage of the internal electrode layer after firing. As a result, the capacitance as a capacitor becomes insufficient.

  Moreover, the sample 13 of the reference example in which the porosity after pressing was as low as 1% resulted in a deterioration of the bike rack removal rate.

Example 3
Pre-baking electrodes according to Samples 14 and 15 in the same manner as Sample 5 of Example 1 except that the content of the nonvolatile organic component was changed to the content shown in Table 3 when the internal electrode paste was prepared. A membrane sample and a multilayer ceramic capacitor sample were each produced.

That is, in sample 14, 20 parts by weight of ceramic powder (BaTiO ₃ ) as a co-material, 2.5 parts by weight of ethyl cellulose resin as a binder, and 1.0 part by weight of an aliphatic ester dispersant as a dispersant. In addition, in sample 15, 5 parts by weight of ceramic powder (BaTiO ₃ ) as a co-material, 5 parts by weight of ethyl cellulose resin as a binder, 5 parts by weight of dioctyl phthalate (DOP) as a plasticizer, as a dispersant The aliphatic ester dispersant was changed to 1.0 part by weight.

  Table 3 shows the evaluation results of the electrode film sample before firing and the capacitor sample when the content of the nonvolatile organic component is changed. In Table 3, Sample 5 is the same sample as Sample 5 of Example 1.

  From Table 3, in the case where the porosity in each step was adjusted by changing the content of the non-volatile organic component from the result of the sample 14 in which the content of the non-volatile organic component was changed to 2.8% by weight. It can also be confirmed that the effects of the present invention are exhibited.

  Similarly, from the result of Sample 15, even when the porosity after coating and drying is outside the range of the present invention by setting the content of the nonvolatile organic component to 9.5% by weight, the same tendency is observed. It can be confirmed.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. 2 (A) and 2 (B) are cross-sectional views showing the main part of a method for forming a green sheet, a pre-fired electrode film, and a blank pattern layer according to an embodiment of the present invention. FIG. 3A is a schematic diagram schematically showing the microstructure of the electrode film before firing of the present invention, and FIG. 3B is a schematic diagram schematically showing the microstructure of the conventional electrode film before firing. . 4 (A) to 4 (C) are main part cross-sectional views showing a method for forming a green sheet, a pre-fired electrode film, and a blank layer according to another embodiment of the present invention. FIG. 5A to FIG. 5C are cross-sectional views of relevant parts showing a step subsequent to FIG. 6A is a cross-sectional photograph showing an example of a bike removal rack, and FIG. 6B is a cross-sectional photograph showing an example of a firing crack. FIG. 7 is a diagram for explaining a method of measuring the electrode coverage. 8A is a cross-sectional photograph of the pre-firing electrode film according to the example of the present invention, and FIG. 8B is a cross-sectional photograph of the pre-firing electrode film according to the comparative example. 9A is a cross-sectional photograph of the element body after firing according to the example of the present invention, and FIG. 9B is a cross-sectional photograph of the element body after firing according to the comparative example.

Explanation of symbols

2 ... Multilayer ceramic capacitor 4 ... Capacitor body 6, 8 ... Terminal electrode 10 ... Dielectric layer 10a ... Green sheet 12 ... Internal electrode layer 12a ... Electrode film before firing 120 ... Conductor powder 122 ... Dielectric powder (co-material)
124 ... Nonvolatile organic component 126 ... Gap 20 ... Carrier sheet (first support sheet)
22 ... Blank pattern layer 24 ... Carrier sheet (second support sheet)
26 ... Release layer 28 ... Carrier sheet (third support sheet)
30 ... Adhesive layer

Claims (10)

A method of manufacturing an electronic component having an internal electrode layer,
Preparing a paste for an internal electrode containing a conductor powder, a solvent, a binder, an inorganic oxide powder, and a dispersant ;
Applying the internal electrode paste, then drying, and forming a pre-fired electrode film that forms the internal electrode layer after firing; and
Pressing the pre-fired electrode film ,
The average particle diameter of the conductor powder contained in the internal electrode paste is in the range of 0.05 to 0.4 μm,
The average particle size of the inorganic oxide powder is in the range of 0.002 to 0.1 μm,
The content of the inorganic oxide powder contained in the internal electrode paste is in the range of 5 to 40 parts by weight with respect to 100 parts by weight of the conductor powder,
The content of the dispersant contained in the internal electrode paste is in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the conductor powder,
The weight density per unit volume of the electrode film before firing after pressing is improved by 3 to 20% compared with the weight density per unit volume of the electrode film before firing before pressing, and the electrode film before firing after pressing The manufacturing method of the electronic component characterized by pressing so that the porosity of 2 may become 2-20% . Heating the pre-fired electrode film after pressing to further remove the binder contained in the pre-fired electrode film;
The method of manufacturing an electronic component according to claim 1, wherein the binder is removed so that the porosity of the electrode film before firing after removing the binder is 5 to 25%.   The content of the organic nonvolatile component consisting of the binder and the dispersant is
  3. The method of manufacturing an electronic component according to claim 1, wherein a content of the non-volatile component contained in the internal electrode paste is in a range of 2.8 to 4.4% by weight. The electronic component further includes a dielectric layer;
Using a dielectric paste, on the support sheet, forming a green sheet that will form the dielectric layer after firing,
Then, on the green sheet, the coating the internal electrode paste, then the method of manufacturing an electronic component according to any one of claims 1 to 3, dried to form the pre-firing electrode film. The electronic component further includes a dielectric layer;
Forming a green sheet on the first support sheet, which will form the dielectric layer after firing;
Applying the internal electrode paste onto the second support sheet and then drying to form the pre-fired electrode film; and
Transferring the pre-fired electrode film formed on the second support sheet to the surface of the green sheet formed on the first support sheet;
The manufacturing method of the electronic component in any one of Claims 1-4 which has these. As the dielectric layer thickness after firing becomes 2.5μm or less, a method of manufacturing an electronic component according to claim 4 or 5 forming the green sheet. The ratio of the thickness of the dielectric layer after firing to the thickness of the internal electrode layer after firing is such that the thickness of the dielectric layer / the thickness of the internal electrode layer = 0.5 to 2.0. the green sheet and method for manufacturing the electronic component according to any one of claims 4-6 for forming the pre-fired electrode film. A plurality of the pre-fired electrode films and a plurality of the green sheets are alternately laminated,
The method for manufacturing an electronic component according to any one of claims 4 to 7 , wherein the number of laminated dielectric layers after firing is 100 or more. When the internal electrode paste is applied on a smooth substrate so that the film thickness after drying is 30 to 45 μm, and then dried with a blow-type dryer at 100 ° C. for 15 minutes. The internal electrode paste according to any one of claims 1 to 8 , wherein the internal electrode paste has a 60 ° specular gloss (Gs (60 °)) of 100% or more on the surface of the obtained coating film. Production method. Electronic component obtainable by the process according to any one of claims 1-9.