JP5221059B2 - Electrode step absorbing printing paste and method for producing multilayer ceramic electronic component - Google Patents

Description

  The present invention relates to an electrode level difference absorbing print paste used for manufacturing a multilayer ceramic electronic component, and a method for manufacturing a multilayer ceramic electronic component using the paste.

  In a multilayer ceramic capacitor as an example of a multilayer ceramic electronic component, a ceramic green sheet is usually formed on a carrier sheet using a dielectric paste by a doctor blade method or the like, and an electrode paste for forming an internal electrode is formed in a predetermined pattern on the ceramic green sheet. And printing and drying to form an internal electrode pattern. Thereafter, the ceramic green sheet is peeled off from the carrier sheet and laminated to a desired number of layers.

  Here, two types of lamination methods are known: a method of peeling the ceramic green sheet from the carrier sheet before lamination (sheet method) and a method of peeling the carrier sheet after lamination pressure bonding (printing method). There is no big difference. Finally, the multilayer body is cut into chips to form green chips. After firing these green chips, a terminal electrode is formed to obtain a multilayer ceramic capacitor.

  By the way, in recent years, electronic devices are becoming lighter, thinner and shorter. Along with this, further downsizing and higher capacity are being promoted also in the multilayer ceramic capacitor used in the electronic device. The most effective way to reduce the size and increase the capacity of multilayer ceramic capacitors is to make both internal electrodes and dielectric layers as thin as possible (thinner layers) and stack them as much as possible ( Multi-layered).

  However, when the ceramic green sheets and the internal electrode patterns are alternately laminated like a multilayer ceramic capacitor, gaps (blank spaces) in which no electrodes are formed on the same row of the internal electrode patterns sandwiched between the ceramic green sheets. Pattern portion) is formed. Due to the blank pattern portion, a step is formed with the portion where the internal electrode pattern exists, and this causes problems such as deformation of the product chip, cracks, and delamination between sheets. In particular, when the thickness of the dielectric layer per layer is further reduced to about the thickness of the internal electrode in order to increase the capacity of the capacitor, the dielectric layer is likely to be cut at the portion where the step is generated. Short circuit defects due to short circuits between internal electrodes tend to occur, and the defect rate tends to increase.

  Therefore, in order to solve various problems caused by such steps in recent years, an electrode step absorbing printing paste is formed in a gap (blank pattern portion) where no internal electrode is formed following the formation of the internal electrode (internal electrode pattern). A technique is known in which a blank pattern layer is formed and laminated while the formation surface is flattened. The internal electrode pattern and the blank pattern layer have a negative and positive relationship with the photographic film.

  As such an electrode level difference absorbing printing paste, a ceramic powder dispersed in an organic vehicle in which an organic binder is dissolved in a solvent is used, similar to a dielectric paste for forming a ceramic green sheet. Yes.

  For example, Patent Document 1 discloses a method of manufacturing a multilayer ceramic electronic component using an electrode step absorption printing paste containing an organic binder made of a mixture of polyvinyl butyral and cellulose ester, a solvent, and ceramic powder. Has been. In Patent Document 1, terpineol is used as a solvent for the electrode level difference absorbing printing paste, and polyvinyl butyral is used as an organic binder for the ceramic green sheet.

  On the other hand, the electrode step absorption printing paste requires a certain degree of viscosity in order to improve the accuracy of the printing pattern, but in order to maintain the viscosity, the organic binder in the electrode step absorption printing paste When the amount is increased, the air permeability of the formed paste layer is deteriorated. As a result, air entrapment occurs during stacking, resulting in a stacking failure, and also due to the effect of gas generated during heat treatment (debinder processing) to remove the organic binder. There was a problem that cracks occurred in the element body before firing.

  In particular, in Patent Document 1 described above, since a relatively large amount of organic binder is contained in the electrode level difference absorbing print paste, stacking failure due to air entrapment during such stacking, or during binder removal processing, is performed. There were problems such as the occurrence of cracks. In Patent Document 1, terpineol is used as a solvent for the electrode level difference absorbing print paste, but the electrode level difference absorbing print paste using terpineol as a solvent is combined with a ceramic green sheet using polyvinyl butyral as an organic binder. When used, a so-called “sheet attack” phenomenon occurs in which the solvent in the paste swells or dissolves the organic binder in the ceramic green sheet.

  In particular, such a sheet attack phenomenon causes the following problems when the thickness of the ceramic green sheet is reduced. That is, when the ceramic green sheet is peeled off from the carrier sheet such as a PET film after the electrode level difference absorbing printing paste is printed, the ceramic green sheet is hardly peeled off. When the ceramic green sheet is difficult to peel off, wrinkles, holes, cracks, etc. occur in the ceramic green sheet due to this influence, and a normal laminate cannot be obtained in the lamination process. If a normal multilayer body cannot be obtained, the final multilayer ceramic electronic component may have a short circuit failure, a withstand voltage failure (IR degradation), or a delamination phenomenon between the dielectric layer and the internal electrode layer (delamination). ) Occurs and the yield decreases.

JP 2001-232617 A

  The present invention has been made in view of such a situation, and the object thereof is used for manufacturing a multilayer ceramic electronic component, and even when the thickness of the ceramic green sheet is reduced, sheet attack can be effectively prevented. In addition, the electrode step absorption printing paste capable of forming a highly breathable blank pattern layer while maintaining a viscosity suitable for printing, and the electrode step absorption printing paste are manufactured with high reliability. It is providing the manufacturing method of the laminated ceramic electronic component which has.

  As the organic binder to be included in the electrode level difference absorbing print paste, the present inventors use ethyl cellulose and polyvinyl butyral, and the solvent contains a specific polyhydric alcohol. The inventors have found that the above object can be achieved and have completed the present invention.

That is, according to the present invention, an electrode step absorption printing paste used for producing a multilayer ceramic electronic component,
Used in combination with ceramic green sheets containing butyral resin,
Including at least ceramic powder, an organic binder, and a solvent,
The content of the binder is 1.0 to 6.0 parts by weight with respect to 100 parts by weight of the ceramic powder,
The organic binder contains ethyl cellulose and polyvinyl butyral, and
There is provided an electrode level difference absorbing printing paste, wherein the solvent contains at least one selected from glycerin, ethylene glycol and butyl carbitol.

Preferably, the content of the solvent is 50 to 200 parts by weight with respect to 100 parts by weight of the ceramic powder,
The total content of glycerin, ethylene glycol and butyl carbitol in the solvent is 3 to 50% by weight with respect to 100% by weight of the whole solvent.

  Preferably, the ratio of ethyl cellulose to polyvinyl butyral in the organic binder is ethyl cellulose: polyvinyl butyral = 95: 5-35: 65 by weight.

According to the present invention, a step of forming a green ceramic laminate by alternately stacking a plurality of ceramic green sheets containing a butyral resin and a predetermined pattern of electrode layers;
Firing the laminate, and a method for producing a multilayer ceramic electronic component comprising:
Before forming the laminate, a blank pattern layer having substantially the same thickness as the electrode layer is formed in a gap portion of the electrode layer of a predetermined pattern,
There is provided a method for manufacturing a multilayer ceramic electronic component, wherein any one of the above electrode level difference absorbing print pastes is used as the electrode level difference absorbing print paste for forming the blank pattern layer.

  The ceramic powder contained in the electrode level difference absorbing printing paste is preferably the same as the ceramic powder contained in the paste for forming the green sheet. This is because the blank pattern layer is a portion integrated with the green sheet after firing.

  The multilayer ceramic electronic component according to the present invention is not particularly limited, and examples thereof include a multilayer ceramic capacitor, a multilayer ceramic inductor, a multilayer ceramic LC component, and a multilayer ceramic substrate.

  According to the present invention, as the organic binder constituting the electrode level difference absorbing printing paste, an organic binder containing ethyl cellulose and polyvinyl butyral is used, and as a solvent, specific polyhydric alcohols, that is, glycerin, ethylene glycol and butyl are used. What contains at least 1 sort (s) selected from carbitol is used. Therefore, according to the electrode level difference absorbing printing paste of the present invention, it is possible to form a blank pattern layer having high air permeability while maintaining a viscosity suitable for printing. Furthermore, even when the thickness of the ceramic green sheet is reduced, sheet attack can be effectively prevented.

  In particular, glycerin, ethylene glycol and butyl carbitol used in the present invention have an effect of improving the air permeability of the blank pattern layer by using in combination with ethyl cellulose and polyvinyl butyral as an organic binder. That is, it acts as a ventilation modifier. Moreover, since these glycerin, ethylene glycol and butyl carbitol also have an effect of improving the paste viscosity, it is possible to optimize the paste viscosity while reducing the amount of the organic binder added. Also, the occurrence of printing blur can be effectively prevented.

  And by using such an electrode level difference absorbing printing paste of the present invention, the blank pattern layer can be formed with excellent printing accuracy, and the formed blank pattern layer has excellent air permeability. Therefore, a highly reliable multilayer ceramic electronic component such as a multilayer ceramic capacitor can be obtained.

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 to 2C are cross-sectional views illustrating a part of the manufacturing process of the multilayer ceramic capacitor of FIG.

  First, an overall configuration of a multilayer ceramic capacitor will be described as an embodiment of the multilayer ceramic electronic component manufactured by the method according to the present invention.

Multilayer Ceramic Capacitor 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 internal electrode layer 12 that is alternately stacked is electrically connected to the inside of the first terminal electrode 6 that is formed outside the first end of the capacitor body 4. The other internal electrode layer 12 that is alternately stacked is electrically connected to the inside of the second terminal electrode 8 formed outside the second end of the capacitor body 4.

  The outer shape and dimensions of the capacitor body 4 are not particularly limited and can be appropriately set according to the application. Usually, the outer shape is substantially a rectangular parallelepiped shape, and the dimensions are usually vertical (0.4 to 5.6 mm) × It can be about horizontal (0.2-5.0 mm) × height (0.2-1.9 mm).

  The dielectric layer 10 is formed by firing a ceramic green sheet 10a shown in FIGS. 2A to 2C described later. 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 the present embodiment, the thickness of the dielectric layer 10 is preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 2 μm or less.

  The internal electrode layer 12 is formed by firing an electrode layer 12a composed of an electrode paste having a predetermined pattern shown in FIGS. 2B and 2C described later. The thickness of the internal electrode layer 12 is preferably 2 μm or less, more preferably 1.5 μm or less.

  The terminal electrodes 6 and 8 are usually made of copper, a copper alloy, nickel, a nickel alloy, or the like, but silver, an alloy of silver and palladium, or the like 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.

Method for Manufacturing Multilayer Ceramic Capacitor Next, an example of a method for manufacturing the multilayer ceramic capacitor 2 according to this embodiment will be described.
(1) First, a dielectric paste (green sheet 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 composed of an organic solvent paste obtained by kneading ceramic powder (dielectric material) and an organic vehicle containing an organic binder and an organic solvent.

  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 2.0 μm or less, preferably about 0.1 to 0.8 μm. In order to form a very thin ceramic green sheet, it is desirable to use a powder finer than the thickness of the ceramic green sheet.

  The organic vehicle is obtained by dissolving an organic binder in an organic solvent. In this embodiment, polyvinyl butyral is used as the organic binder used in the organic vehicle. By using polyvinyl butyral as the organic binder, the obtained ceramic green sheet can be made highly adhesive and flexible. Although content of an organic binder is not specifically limited, Preferably it is more than 5 weight part with respect to 100 weight part of ceramic powders, and less than 9 weight part, More preferably, it is 6-8 weight part. If the content of polyvinyl butyral as an organic binder is too small, the resulting ceramic green sheet laminate property tends to deteriorate, and if it is too large, it will not be completely removed in the binder removal process and many cracks will occur in the sintered body. Tend to.

  The degree of polymerization of polyvinyl butyral is preferably 500 to 2800, more preferably 1000 to 1700. Further, the degree of butyralization is preferably 64 to 78%, and the amount of residual acetyl groups is preferably 6% or less.

  The degree of polymerization of polyvinyl butyral can be measured, for example, by the degree of polymerization of polyvinyl acetal as a raw material. Further, the degree of butyralization can be measured according to, for example, JIS K6728. Furthermore, the amount of residual acetyl groups can be measured according to JIS K6728.

  If the degree of polymerization of polyvinyl butyral is too small, sufficient mechanical strength tends to be hardly obtained when the obtained ceramic green sheet is thinned to a thickness of, for example, 5 μm or less, preferably about 3 μm or less. On the other hand, if the degree of polymerization is too high, the surface roughness tends to deteriorate when the sheet is formed. Moreover, when the degree of butyralization of polyvinyl butyral is too low, the solubility in the paste tends to decrease, and when it is too high, the surface roughness of the resulting green sheet tends to deteriorate. Furthermore, when there is too much residual acetyl group amount, it exists in the tendency for the surface roughness of the green sheet obtained to deteriorate.

  The organic solvent used in the organic vehicle is not particularly limited, and for example, terpineol, alcohol, butyl carbitol, acetone, toluene and the like are used. Further, the content of the organic solvent in the dielectric paste is not particularly limited, and may be in the range of 1 to 50% by weight.

  The dielectric paste may contain additives selected from various dispersants, plasticizers, antistatic agents, dielectrics, glass frit, insulators and the like as required. When these additives are added to the dielectric paste, the total content is desirably about 10% by weight or less.

  Although it does not specifically limit as a dispersing agent, Preferably a polyethyleneglycol type nonionic dispersing agent is used, and the thing of the hydrophilicity-lipophilic balance (HLB) value of 5-6 is preferable. The dispersant is preferably 0.5 to 1.5 parts by weight, more preferably 0.5 to 1.0 parts by weight with respect to 100 parts by weight of the ceramic powder.

  Examples of the plasticizer include phthalic acid esters such as benzylbutyl phthalate (BBP), adipic acid, phosphoric acid esters, glycols, and the like. The proportion of the plasticizer in the dielectric paste when the plasticizer is blended is not particularly limited, but is preferably 40 to 70 parts by weight with respect to 100 parts by weight of the organic binder. If the amount of the plasticizer is too small, the elongation and flexibility of the green sheet tend to be deteriorated. If the amount is too large, the plasticizer oozes out on the surface of the green sheet, making handling difficult.

  The dielectric paste can be obtained by kneading the above components with a ball mill or the like to form a slurry.

  (2) Next, using this dielectric paste, a wire bar coater, a doctor blade method, or the like, as shown in FIG. The ceramic green sheet 10a is formed with a thickness of about 30 μm, more preferably about 0.5 to 10 μm. The green sheet 10 a is dried after being formed on the carrier sheet 20. 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. The thickness of the green sheet after drying is preferably 5 μm or less, more preferably 3 μm or less.

  As the carrier sheet 20, for example, a PET film is used, and in order to improve the peelability, a surface on which the ceramic green sheet 10 a is formed is preferably subjected to a release treatment (coating with silicone or the like). . Although the thickness of the carrier sheet 20 is not specifically limited, Preferably it is 5-100 micrometers.

  (3) Next, as shown in FIG. 2B, on the surface of the ceramic green sheet 10a formed on the carrier sheet 20, an electrode layer having a predetermined pattern that becomes the internal electrode layer 3 shown in FIG. Internal electrode pattern) 12a is formed.

  The thickness of the electrode layer 12a is 2 μm or less, preferably 0.5 to 1.5 μm. If the thickness of the electrode layer 12a is too large, the number of stacked layers must be reduced, and this reduces the acquired capacity and makes it difficult to increase the capacity. On the other hand, if the thickness is too thin, it is difficult to form uniformly, and electrode breakage is likely to occur. Note that the thickness of the electrode layer 12a is in the above range in the current technology, but it is more desirable that the electrode layer 12a be thin in a range where the electrode is not interrupted.

  The method for forming the electrode layer 12a is not particularly limited as long as the layer can be formed uniformly. In this embodiment, a screen printing method using an electrode paste is used.

  The electrode paste used in the present embodiment includes a conductive material made of various conductive metals and alloys, or various oxides, organometallic compounds, or resinates that become the conductive material described above after firing, an organic binder, and an organic solvent. And kneading the organic vehicle.

  As a conductive material used when manufacturing the electrode paste, Ni, Ni alloy, or a mixture thereof is used. There are no particular restrictions on the shape of such a conductive material, such as a spherical shape or a flake shape, or a mixture of these shapes may be used. The average particle diameter of the conductor material is usually 0.1 to 2 μm, preferably about 0.2 to 1 μm. The conductive material is preferably contained in the electrode paste by 30 to 60% by weight, more preferably 40 to 50% by weight.

  Examples of the organic binder used in the organic vehicle include ethyl cellulose, alkyd resin, acrylic resin, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyolefin, polyurethane, polystyrene, and copolymers thereof. In the embodiment, it is more preferable that ethyl cellulose is a main component. The organic binder is preferably contained in the electrode paste in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of the conductor material (metal powder).

  In order to improve adhesion, the electrode paste preferably contains a plasticizer. As a plasticizer, the same thing as the dielectric paste mentioned above can be used.

  The electrode paste can be obtained by kneading the above components with a ball mill or the like to form a slurry.

  (4) In this embodiment, the electrode layer 12a shown in FIG. 2B is not formed after or before the electrode layer 12a having a predetermined pattern is formed on the surface of the ceramic green sheet 10a by the printing method. As shown in FIG. 2C, a blank pattern layer 22 having substantially the same thickness as the electrode layer 12a is formed in the surface gap (blank pattern portion 30) of the ceramic green sheet 10a. The reason why the thickness of the blank pattern layer 22 is set to be substantially the same as that of the electrode layer 12a is that a step is formed unless it is substantially the same.

  In this embodiment, the blank pattern layer 22 is formed by a screen printing method using an electrode level difference absorbing printing paste.

  The electrode level difference absorbing printing paste used in the present embodiment contains ceramic powder and an organic vehicle containing an organic binder and an organic solvent.

  As the ceramic powder used when manufacturing the electrode level difference absorbing printing paste, it is preferable to use the same ceramic powder as the dielectric constituting the green sheet 10a. This is because the blank pattern layer 22 formed of the electrode level difference absorbing print paste is integrated with the dielectric layer 10 after firing.

  The ceramic powder is preferably contained in the electrode level difference absorbing printing paste in an amount of 30 to 70% by weight, more preferably 40 to 55% by weight. If the content of the ceramic powder is too small, the paste viscosity becomes small and printing becomes difficult. Moreover, when there is too much content rate of ceramic powder, it exists in the tendency for it to become difficult to make printing thickness thin.

  As the organic binder used in the organic vehicle, in this embodiment, two kinds of resins, ethyl cellulose and polyvinyl butyral, are mixed and used. By using a mixture of ethyl cellulose and polyvinyl butyral, the blank paste layer 22 can be made porous, whereby the air permeability of the blank paste layer 22 can be improved. The content of the organic binder in the electrode level difference absorbing printing paste is 1.0 to 6.0 parts by weight, preferably 2 to 5 parts by weight, more preferably 3.5 to 4 parts by weight based on 100 parts by weight of the ceramic powder. .5 parts by weight. If the amount of the organic binder is too small, the strength of the blank paste layer 22 is significantly reduced. On the other hand, if too much, the air permeability of the blank paste layer 22 is lowered.

  The ratio of ethyl cellulose to polyvinyl butyral in the organic vehicle is preferably a weight ratio of ethyl cellulose: polyvinyl butyral = 95: 5 to 35:65, more preferably 93: 7 to 50:50, still more preferably. 90:10 to 70:30. When the ratio of ethyl cellulose is too high, the viscosity of the electrode level difference absorbing printing paste becomes too high, and when the blank pattern layer 22 is formed, the surface tends to become rough. On the other hand, when the ratio of polyvinyl butyral is too high, the viscosity of the electrode level difference absorbing print paste tends to be too low, and printing bleeding tends to occur. Furthermore, since polyvinyl butyral is the same kind as the organic binder of the ceramic green sheet, if the amount is too large, a sheet attack phenomenon to the green sheet is likely to occur.

  As polyvinyl butyral, the same material as the above-described dielectric paste may be used.

  As the organic solvent used in the organic vehicle, a solvent containing at least one selected from glycerin, ethylene glycol, and butyl carbitol is used. By containing these glycerin, ethylene glycol, and butyl carbitol in an organic solvent, the electrode step absorption printing paste is formed with the electrode step absorption printing paste while maintaining the viscosity of the electrode step absorption printing paste in an appropriate range for printing. The air permeability of the blank pattern layer 22 can be improved. That is, these solvents act as an air flow modifier by being used in combination with ethyl cellulose and polyvinyl butyral which are organic binders. This is probably because glycerin, ethylene glycol and butyl carbitol have low compatibility with organic binders such as ethyl cellulose and polyvinyl butyral, and also have a relatively high boiling point. . Among glycerin, ethylene glycol, and butyl carbitol, glycerin is particularly preferable from the viewpoint that the effect of improving characteristics is large.

  The content of the organic solvent in the electrode level difference absorbing print paste is preferably 50 to 200 parts by weight, more preferably 55 to 65 parts by weight with respect to 100 parts by weight of the ceramic powder. Further, the total content of glycerin, ethylene glycol and butyl carbitol as the air flow modifier in the organic solvent is determined when the total amount of the organic solvent to be contained in the electrode step absorption printing paste is 100% by weight. The amount is preferably 3 to 50% by weight, more preferably 10 to 30% by weight, and still more preferably 13 to 20% by weight. If the content ratio of glycerin, ethylene glycol and butyl carbitol as the air flow modifier is too low, the effect of improving the characteristics cannot be obtained. On the other hand, when the amount is too large, the viscosity of the electrode level difference absorbing printing paste tends to increase, which causes a decrease in printing accuracy.

  In addition, as another solvent used in combination with one kind of solvent selected from glycerin, ethylene glycol, and butyl carbitol, those that are highly compatible with the organic binder and do not attack the ceramic green sheet 10a. Preferable examples include terpinyl acetate and dihydroterpineol, and these can be used in combination. Moreover, as such a solvent, a solvent having a low boiling point is preferable as compared with glycerin, ethylene glycol and butyl carbitol.

  In addition, the electrode level difference absorbing printing paste may contain various additives such as a dispersant, a plasticizer, an adhesive, and an antistatic agent.

  Although there is no limitation in particular as a dispersing agent, For example, polymeric materials, such as ester polymer and carboxylic acid, are used. The content of the dispersant is preferably 0.1 to 10 parts by weight, more preferably 0.3 to 1 part by weight with respect to 100 parts by weight of the ceramic powder.

  The plasticizer is not particularly limited. For example, phthalates such as dibutyl phthalate (DBP), dioctyl phthalate (DOP), benzyl butyl phthalate (BBP), and butyl butylene glycol phthalate (BPBG), adipine Examples include adipic acid esters such as dioctyl acid (DOA) and sebacic acid esters such as dibutyl sebacate. Of these, dioctyl phthalate (DOP) is particularly preferred. The content of the plasticizer is preferably 50 to 200 parts by weight, more preferably 80 to 100 parts by weight with respect to 100 parts by weight of the organic binder.

  The antistatic agent is not particularly limited, and for example, an imidazoline-based antistatic agent is used. The content of the antistatic agent is preferably 0.1 to 0.75 parts by weight, more preferably 0.25 to 0.5 parts by weight, with respect to 100 parts by weight of the ceramic powder.

  The electrode level difference absorbing printing paste can be obtained by kneading the above components with a ball mill or the like to form a slurry.

  This electrode level difference absorbing print paste is printed on the blank pattern portion 30 between the electrode layers 12a shown in FIG. Thereafter, the blank pattern layer 22 formed by printing the electrode level difference absorbing printing paste is preferably dried at a temperature of 40 to 90 ° C. in order to remove the organic solvent. The drying may be performed together with the electrode layer 12a or may be performed separately.

  (5) Next, a plurality of ceramic green sheets 10a having a predetermined pattern of the electrode layer 12a and the blank pattern layer 22 formed on the surface as described above are laminated to form a laminate, and the obtained laminate is made to a predetermined size. Cut into green chips. Thereafter, the green chip is subjected to binder removal processing.

The binder removal treatment may be performed under normal conditions. However, when a base metal such as Ni or Ni alloy is used as the conductor material of the internal electrode layer, the heating rate is 5 to 300 ° C./hour, particularly 5 to 50 ° C./hour. Time, holding temperature: 200 to 700 ° C., particularly 300 to 650 ° C., holding time: 0.5 to 20 hours, particularly 1 to 10 hours, atmosphere: preferably a mixed gas of humidified N ₂ and H ₂ .

  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, in the above-described embodiment, the multilayer ceramic capacitor is exemplified as the multilayer ceramic electronic component manufactured according to the present invention. However, any multilayer ceramic electronic component to which the electrode level difference absorbing print paste of the present invention can be applied is used. good.

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

Example 1
Preparation of Electrode Step Absorption Printing Paste BaTiO ₃ powder (BT-02 / Sakai Chemical Industry Co., Ltd.) as a starting material for ceramic powder, and 100 parts by weight of BaTiO ₃ powder as an additive component (Ba _{0 .6} Ca _0.4 ) SiO ₃ : 1.48 parts by weight, Y ₂ O ₃ : 1.01 parts by weight, MgCO ₃ : 0.72 parts by weight, Cr ₂ O ₃ : 0.13 parts by weight, and V ₂ O ₅ : 0.045 part by weight was prepared.

And the ceramic powder prepared above (BaTiO ₃ and additive components): 100 parts by weight, as an organic binder, a mixture of ethyl cellulose and polyvinyl butyral (ethyl cellulose: polyvinyl butyral = 85: 15 (weight ratio)): 3.5 Part by weight, organic solvent, mixed solvent of terpinyl acetate and glycerin (aeration modifier): 135 parts by weight, DOP (dioctyl phthalate) as a plasticizer component: 5.5 parts by weight, and as a dispersant Polyethylene glycol-based nonionic dispersant (HLB = 5 to 6): 0.5 part by weight was mixed with a ball mill to obtain an electrode step absorbing printing paste.

  In this example, as shown in Table 1, a plurality of pastes (sample numbers 1 to 6) in which the ratio of terpinyl acetate and glycerin (aeration modifier) was changed as an organic solvent were obtained. . For example, in Sample No. 4 in Table 1, the ratio in the organic solvent is terpinyl acetate: glycerin (aeration modifier) = 83.8 wt%: 16.2 wt%. Furthermore, sample number 1 in Table 1 is a sample that did not use glycerin (aeration modifier).

  Polyvinyl butyral having a polymerization degree of 2600, a butyralization degree of 64.5%, and a residual acetyl group content of 0.9% was used. In addition, as a polyethylene glycol-based nonionic dispersant (HLB = 5 to 6) as a dispersant, a block polymer of polyethylene glycol and a fatty acid ester was used.

  And about the obtained electrode level | step difference absorption printing paste, the sheet attack to a green sheet, air permeability, and a viscosity were evaluated in accordance with the following method.

Sheet Attack First, a ceramic green sheet for forming the dielectric layer 10 shown in FIG. 1 was produced by the following method.
That is, the same ceramic powder as the ceramic powder (BaTiO ₃ and additive components) used for the production of the electrode level difference absorbing printing paste was prepared. Next, ceramic powder: 100 parts by weight, polyvinyl butyral as an organic binder: 6 parts by weight, mixed solvent as an organic solvent (mixed solvent containing (methyl ethyl ketone) as a main component): 120 parts by weight, and DOP as a plasticizer component (Dioctyl phthalate): A dielectric paste was obtained by mixing 3 parts by weight with a ball mill. Next, using the obtained dielectric paste, it was applied onto a PET film using a wire bar coater and then dried to form a ceramic green sheet having a thickness of 8 μm.

  Next, the obtained ceramic green sheet is printed by screen printing with the electrode level difference absorbing printing paste prepared above, and then dried to form a blank pattern layer having a thickness of 1.5 μm. A sample for attack evaluation was obtained.

  The obtained sheet attack evaluation sample is observed with a microscope from the surface opposite to the blank pattern layer of the ceramic green sheet (the surface in contact with the PET film), and the ceramic green sheet is dissolved according to the degree of deformation and the hue. By checking the degree, the presence or absence of a sheet attack was evaluated. A case where the dissolution of the ceramic green sheet could not be confirmed was judged as ◯, and a case where the dissolution was confirmed as x. The results are shown in Table 1.

Breathable First, using the same paste and dielectric paste was prepared in the evaluation of the above sheet attack, in the same manner to form a ceramic green sheet having a thickness of 2 [mu] m. Then, on the obtained ceramic green sheet, the electrode step absorbing printing paste prepared above is printed on the entire surface by screen printing, and then dried to form a blank pattern layer having a thickness of 1 to 1.5 μm. Finally, a plurality of ceramic green sheets on which blank pattern layers were formed were laminated so that the total thickness was 30 μm (3 layers in total), thereby preparing a sample for air permeability evaluation.

  And before and after interposing the sample for air permeability evaluation, when applying the air pressure of 320 Torr to the obtained air permeability evaluation sample and adjusting the flow rate to be 1 L / min The pressure change rate was measured, and the ventilation resistance (unit: Torr) was calculated from the measurement results. It can be evaluated that the lower the ventilation resistance, the better the air permeability. The results are shown in Table 1.

The viscosity of the viscosity electrode step absorption printing paste was determined by measuring the viscosity V ₈ at a shear rate of ₈ sec ⁻¹ using a viscoelasticity measuring device (rheometer). The results are shown in Table 1.

  From Table 1, the electrode step absorption printing paste obtained by using a predetermined amount of ethyl cellulose and polyvinyl butyral as the organic binder and adding glycerin as the air flow modifier can be printed with an appropriate paste viscosity. While maintaining the range, it can be confirmed that the sheet attack can be effectively prevented, and further, the air permeability of the obtained sheet can be increased (the air resistance can be decreased). On the other hand, when glycerin as the air flow modifier was not added, the paste viscosity was lowered.

Example 2
Sample No. 4 in Example 1 except that the addition amount of a mixture of ethyl cellulose and polyvinyl butyral as an organic binder (ethyl cellulose: polyvinyl butyral = 85: 15 (weight ratio)) was changed as shown in Table 2. Similarly, electrode level difference absorbing print paste was prepared and evaluated in the same manner. That is, in Example 2, the addition amount of the mixture of ethyl cellulose and polyvinyl butyral was 3 parts by weight (sample number 7) and 2.5 parts by weight (sample number 8) with respect to 100 parts by weight of the ceramic powder. A sample having 2 parts by weight (sample number 9) was prepared. The results are shown in Table 2.

  From Table 2, it can be confirmed that similar results can be obtained even when the amount of the mixture of ethyl cellulose and polyvinyl butyral as the organic binder is changed. Sample number 4 in Table 2 is the same sample as sample number 4 in Example 1.

Example 3
An electrode level difference absorbing printing paste was prepared and evaluated in the same manner as Sample No. 4 in Example 1 except that the ventilation modifier shown in Table 3 was used instead of glycerin as the ventilation modifier. Went. That is, in Example 3, a sample using ethylene glycol (sample number 10), butyl carbitol (sample number 11), tetramethylene glycol (sample number 12), and diethylene glycol (sample number 13) as the aeration modifier. Was made. The results are shown in Table 3.

  From Table 3, it can be confirmed that the same results can be obtained when ethylene glycol and butyl carbitol are used instead of glycerin as the aeration modifier. On the other hand, when tetramethylene glycol and diethylene glycol were used instead of glycerin, when preparing the paste, each component was separated, and a printable paste could not be obtained. Sample number 4 in Table 3 is the same sample as sample number 4 in Example 1.

Reference Experiment Example In order to confirm the tendency when the ratio of ethyl cellulose as an organic binder to polyvinyl butyral was changed in the electrode level difference absorbing print paste, an electrode level difference absorbing print paste having the composition shown in Table 4 was prepared. The same evaluation as in Example 1 was performed. In this reference experimental example, as compared with Example 1, the ratio of ethyl cellulose and polyvinyl butyral was changed as shown in Table 4, and the amount of organic binder added was increased to 4.7 parts by weight. Also, glycerin as an aeration modifier was not used.

  From Table 4, when the ratio of polyvinyl butyral is increased, it can be confirmed that sheet attack tends to occur and the paste viscosity tends to decrease. Further, when no ethyl cellulose was added, each component was separated when the paste was produced, and a printable paste could not be obtained.

  Further, by comparing the sample number 16 of Example 1 having a paste viscosity substantially equal to the sample number 16, according to the practice of the present invention, while maintaining the paste viscosity in a range suitable for printing, the air permeability It can be confirmed that improvement is possible.

Example 4
By using the electrode step absorption printing paste of Sample No. 4 of Example 1, the dielectric paste used for evaluation of the sheet attack of Example, and the electrode paste obtained by the following method, by the method described below, A multilayer ceramic capacitor sample was prepared.

  That is, as the electrode paste, a powder prepared by mixing Ni powder: 100 parts by weight, ethyl cellulose as an organic binder: 4.5 parts by weight, and dihydroterpineol as an organic solvent: 100 parts by weight with a ball mill is used. did.

  First, a dielectric paste was applied to a PET film with a predetermined thickness by a doctor blade method and dried to produce an outer layer green sheet having a thickness of 20 μm. Similarly, an inner layer ceramic green sheet having a thickness of 3 μm was prepared. In this embodiment, the inner layer green sheet is sandwiched between the five outer layer green sheets (100 μm). A plurality of ceramic green sheets for the inner layer were prepared as first green sheets.

  Next, an electrode layer (internal electrode pattern) 12a (see FIG. 2B) having a thickness of about 1.5 μm was formed on the obtained first green sheet by screen printing using an electrode paste. . Thereafter, the electrode level difference absorbing print paste of sample number 4 of Example 1 is applied to the blank pattern portion 30 (see FIG. 2B) where the electrode layer 12a is not formed on the first green sheet by the screen printing method. Printing was performed to form a blank pattern layer 22 (see FIG. 2C) having substantially the same thickness as the electrode layer 12a. And these were dried, and the ceramic green sheet 10a which has the electrode layer 12a and the blank pattern layer 22 as shown in FIG.2 (C) was obtained. In this example, this ceramic green sheet 10a was used as a second green sheet, and a plurality of these were prepared.

Next, the green sheet group was formed by laminating the outer layer green sheets until the thickness reached 100 μm. On this green sheet group, 200 second green sheets are laminated, and further, an outer layer green sheet group is laminated and formed thereon, and heated under conditions of a temperature of 60 ° C. and a pressure of 1.0 ton / cm ^2. -Pressurized to obtain a green ceramic laminate.

Next, after cutting the obtained laminated body into a predetermined size, binder removal processing, firing and annealing were performed under the following conditions to obtain a sintered body. The binder removal was performed under the conditions of a temperature rising rate: 15 ° C./hour, a holding temperature: 280 ° C., a holding time: 8 hours, and a processing atmosphere: an air atmosphere. Firing is performed at a heating rate of 200 ° C./hour, a holding temperature of 1200 to 1380 ° C., a holding time of 2 hours, a cooling rate of 300 ° C./hour, a processing atmosphere: a reducing atmosphere (oxygen partial pressure: 10 ⁻⁶ Pa to N The mixed gas of ₂ and H ₂ was adjusted by passing water vapor). The annealing was performed under the conditions of a holding temperature: 900 ° C., a holding time: 9 hours, a cooling rate: 300 ° C./hour, and a processing atmosphere: a humidified N ₂ gas atmosphere. A wetter was used to wet the gas during firing and annealing, and the water temperature was set to 35 ° C.

  Next, after polishing the end face of the obtained sintered body by sand blasting, an In—Ga alloy was applied to form a test electrode, and a multilayer ceramic chip capacitor sample shown in FIG. 1 was obtained. The size of the capacitor sample is 1.6 mm long × 0.8 mm wide × 0.8 mm high. The thickness of the dielectric layer 2 sandwiched between the pair of internal electrode layers is about 2 μm, and the thickness of the internal electrode layer 3 is 1. It was 5 μm.

Measurement of short-circuit defect rate The short-circuit defect rate was measured using the obtained capacitor sample. The short-circuit defect rate was measured by preparing 50 capacitor samples and examining the number of short-circuit defects. Specifically, the resistance value was measured using an insulation resistance meter (E2377A multimeter manufactured by HEWLETT PACKARD), and the sample having a resistance value of 100 kΩ or less was defined as a short defect sample. The ratio of samples was defined as the short defect rate. In this example, the case where the short-circuit defect rate was 10% or less was considered good. As a result, the short-circuit defect rate was 5%, and a very good result was obtained.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. 2A to 2C are cross-sectional views illustrating a part of the manufacturing process of the multilayer ceramic capacitor of FIG.

Explanation of symbols

2 ... Multilayer ceramic capacitor 4 ... Capacitor body 6, 8 ... Terminal electrode 10 ... Dielectric layer 10a ... Ceramic green sheet 12 ... Internal electrode layer 12a ... Electrode layer (internal electrode pattern)
20 ... Carrier sheet 22 ... Blank pattern layer 30 ... Blank pattern part

Claims (4)

An electrode level difference absorbing printing paste used for manufacturing a multilayer ceramic electronic component,
Used in combination with ceramic green sheets containing butyral resin,
Including at least ceramic powder, an organic binder, and a solvent,
The content of the binder is 1.0 to 6.0 parts by weight with respect to 100 parts by weight of the ceramic powder,
The organic binder contains ethyl cellulose and polyvinyl butyral, and
The solvent contains at least one selected from glycerin and ethylene glycol ;
The content of the solvent is 50 to 200 parts by weight with respect to 100 parts by weight of the ceramic powder,
The electrode level difference absorbing printing paste , wherein the total content of glycerin and ethylene glycol in the solvent is 3 to 50% by weight with respect to 100% by weight of the whole solvent . 2. The electrode level difference absorbing printing paste according to claim 1 , wherein a ratio of ethyl cellulose to polyvinyl butyral in the organic binder is ethyl cellulose: polyvinyl butyral = 95: 5 to 35:65 by weight ratio. Forming a green ceramic laminate by alternately stacking a plurality of ceramic green sheets containing a butyral resin and a predetermined pattern of electrode layers;
Firing the laminate, and a method for producing a multilayer ceramic electronic component comprising:
Before forming the laminate, a blank pattern layer having substantially the same thickness as the electrode layer is formed in a gap portion of the electrode layer of a predetermined pattern,
A method for manufacturing a multilayer ceramic electronic component, wherein the electrode level difference absorbing print paste according to claim 1 or 2 is used as the electrode level difference absorbing print paste for forming the blank pattern layer. The method for producing a multilayer ceramic electronic component according to claim 3 , wherein the ceramic powder contained in the electrode level difference absorbing printing paste is the same as the ceramic powder contained in the paste for forming the green sheet.

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