JP4978518B2 - Manufacturing method of multilayer ceramic electronic component - Google Patents

Description

  The present invention relates to a method for manufacturing a multilayer ceramic electronic component, and more specifically, a multilayer ceramic electronic component capable of improving sheet lamination and sheet adhesion even when a green sheet is thinned. It relates to a manufacturing method.

  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 internal electrode paste for forming an internal electrode is formed thereon. The pattern is printed and dried 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, this laminate is cut into chips to produce green chips. After firing these green chips, external electrodes are 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, especially when the ceramic green sheet is made thinner, the solvent in the internal electrode paste printed on the ceramic green sheet causes the organic binder in the ceramic green sheet to swell or dissolve, so-called “sheet attack” phenomenon Is a problem. That is, when the “sheet attack” phenomenon occurs, wrinkles, holes, cracks, and the like occur in the ceramic green sheet, and short circuit defects and delamination phenomena (delamination) occur in the final multilayer ceramic electronic component. In order to prevent this “sheet attack” phenomenon, the binders are incompatible with each other. For example, in Patent Document 1, polyvinyl butyral resin is used as the organic binder contained in the dielectric paste, and ethyl cellulose is used as the organic binder contained in the internal electrode paste.

  In order to improve the adhesion between the organic binder resin contained in the green sheet and the ethyl cellulose contained in the internal electrode paste, in Patent Documents 2 and 3, the internal electrode paste contains a tackifier such as rosin. Yes.

However, when the binder resin contained in the green sheet and the binder resin contained in the internal electrode paste are incompatible as described above, the adhesiveness deteriorates at the same time. In such a case, the tackifier is hardly studied and the productivity is deteriorated.
JP 2005-243561 A JP-A-5-90069 JP 2004-186339 A

  The object of the present invention is to reduce the thickness of the ceramic green sheet and reduce the strength of the ceramic green sheet. Further, the binder contained in each of the green sheet and the internal electrode pattern layer is an incompatible combination. Even if it exists, it is providing the manufacturing method of the laminated ceramic electronic component which can make the lamination property and adhesiveness of a green sheet favorable, and can prevent the crack after baking, etc. effectively.

  In order to improve the adhesion between the internal electrode pattern layer and the green sheet when the incompatible ethyl cellulose and butyral resin are combined as the binder contained in the internal electrode pattern layer and the green sheet, the present inventors The present inventors have found that it is necessary to use as a specific tackifier depending on the degree of polymerization of the butyral resin, and have completed the present invention.

That is, the method for manufacturing a multilayer ceramic electronic component according to the present invention includes:
A method for producing a multilayer ceramic electronic component comprising a step of alternately stacking a plurality of ceramic green sheets containing ceramic powder and butyral resin and a predetermined pattern of internal electrode pattern layers to obtain a green ceramic laminate,
The degree of polymerization of the butyral resin is 1000-2400,
The internal electrode paste for forming the internal electrode pattern layer has a conductor powder and an organic binder,
The organic binder has ethyl cellulose and at least one selected from gum rosin, rosin glycerin ester and alicyclic petroleum resin as a tackifier,
The organic binder is contained in an amount of more than 2 parts by weight and less than 9 parts by weight with respect to 100 parts by weight of the conductor powder, and the content ratio of the tackifier with respect to the content of the organic binder is 5 to 50% by weight. It is characterized by that.

  The butyral resin contained in the ceramic green sheet and the ethyl cellulose contained in the internal electrode pattern layer are incompatible with each other, and so-called “sheet attack” does not occur. However, the green sheet containing a butyral resin and the internal electrode pattern layer containing ethyl cellulose have poor adhesion, resulting in poor lamination during lamination. Furthermore, in order to prevent the peeling failure from the support, it is necessary to maintain the strength of the green sheet itself. For this reason, a highly polymerized butyral resin is used as the binder resin.

  In the present invention, as the tackifier, the internal electrode paste contains at least one selected from gum rosin, rosin glycerin ester and alicyclic petroleum resin in the above ratio. By doing so, the above-mentioned tackifier is compatible with a high polymerization degree butyral resin and ethyl cellulose. As a result, the adhesion between the green sheet and the internal electrode pattern layer is improved, and the sheet stackability (stack) Property) can be improved. In addition, by including such a tackifier, the content of ethyl cellulose having a high firing temperature can be reduced, so that the binder removal is facilitated.

  Preferably, the butyral resin is contained more than 5 parts by weight and less than 10 parts by weight with respect to 100 parts by weight of the ceramic powder.

  Preferably, the weight average molecular weight of the ethyl cellulose is 190,000 or more and less than 250,000.

  Preferably, the ethyl cellulose has an ethoxyl group content of more than 46.1% by weight and less than 52.0% by weight, more preferably 48.0 to 49.5% by weight.

  Preferably, the degree of butyralization of the butyral resin is more than 55 mol% and less than 77 mol%.

  By making the characteristics of ethyl cellulose and butyral resin within the above ranges, the effects of the present invention can be further enhanced.

In addition, a method for manufacturing a multilayer ceramic electronic component according to the present invention includes:
A method for producing a multilayer ceramic electronic component comprising a step of alternately stacking a plurality of ceramic green sheets containing ceramic powder and butyral resin and a predetermined pattern of internal electrode pattern layers to obtain a green ceramic laminate,
The degree of polymerization of the butyral resin is 1000-2400,
The butyral degree of butyral resin is more than 55 mol% and 63 mol% or less,
The internal electrode paste for forming the internal electrode pattern layer has a conductor powder and an organic binder,
The organic binder has ethyl cellulose and terpene phenol as a tackifier,
The organic binder is contained in an amount of more than 2 parts by weight and less than 9 parts by weight with respect to 100 parts by weight of the conductor powder, and the content ratio of the tackifier with respect to the content of the organic binder is 5 to 50% by weight. It is characterized by that.

  The multilayer ceramic electronic component manufactured by the method 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.

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.
2 (A) to 2 (C) are main part cross-sectional views showing a part of the manufacturing process of the multilayer ceramic capacitor shown in FIG.
3 (A) and 3 (B) are cross-sectional views of the main part showing the continuation of the manufacturing process shown in FIGS. 2 (A) to 2 (C).

  In the present embodiment, a multilayer ceramic capacitor will be described as an example of a multilayer ceramic electronic component.

Multilayer Ceramic Capacitor As shown in FIG. 1, a multilayer ceramic capacitor 1 according to an embodiment of the present invention includes a capacitor body 10 having a configuration in which dielectric layers 2 and internal electrode layers 3 are alternately stacked. A pair of external electrodes 4, 4 are formed at both ends of the capacitor body 10 and are electrically connected to the internal electrode layers 3 arranged alternately in the body 10. The internal electrode layers 3 are laminated so that the side end faces are alternately exposed on the surfaces of the two opposite ends of the capacitor body 10. The pair of external electrodes 4, 4 are formed at both ends of the capacitor body 10 and are connected to the exposed end surfaces of the alternately arranged internal electrode layers 3 to constitute a capacitor circuit.

  The outer shape and dimensions of the capacitor body 10 are not particularly limited and can be appropriately set depending on 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 2 is formed by firing a ceramic green sheet 30 shown in FIGS. 2A to 2C, which will be described later, and the material thereof is not particularly limited. For example, calcium titanate, strontium titanate and And / or a dielectric material such as barium titanate. In the present embodiment, the thickness of the dielectric layer 2 is preferably reduced to 1 μm or less.

  The internal electrode layer 3 is formed by firing an internal electrode pattern layer 40 having a predetermined pattern shown in FIG. 2B and FIG. In this embodiment, the thickness of the internal electrode layer 3 is preferably 1 μm or less.

  As the material of the external electrode 4, copper, a copper alloy, nickel, a nickel alloy, or the like is usually used, but silver, a silver-palladium alloy, or the like can also be used. The thickness of the external electrode 4 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 1 according to this embodiment will be described.
Preparation of Dielectric Paste (1) First, a dielectric paste is prepared in order to manufacture a ceramic green sheet that will constitute the dielectric layer 2 shown in FIG. 1 after firing.

  In the present embodiment, the dielectric paste is composed of an organic solvent-based 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 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.

  In this embodiment, the butyral resin as the organic binder used in the organic vehicle is a polyvinyl butyral resin. The polyvinyl butyral resin is preferably contained in an amount of more than 5 parts by weight and less than 10 parts by weight, more preferably 6 to 9 parts by weight with respect to 100 parts by weight of the ceramic powder. If the content of the polyvinyl butyral resin is too small, the sheet lamination property (stackability) tends to deteriorate, and if it is too large, it is not completely removed in the binder removal step, and many cracks tend to occur in the sintered body. is there.

In this invention, the polymerization degree of polyvinyl butyral resin is 1000-2400, Preferably it is 1000-2400 (however, except 1000), More preferably, it is 1700-2400. By using a polyvinyl butyral resin having a high degree of polymerization as described above, the strength of the green sheet is improved, and the handling property is good even when it is peeled off from the carrier sheet before lamination. However, in this case, the adhesion between the green sheet and the internal electrode pattern layer tends to deteriorate. Therefore, in the present invention, the adhesiveness is improved by including a specific tackifier described later in the internal electrode paste. As a result, even if the green sheets are thinned, it becomes easier to bond the green sheets at the time of lamination while maintaining sufficient strength.
If the degree of polymerization is too small or too large, the adhesion between the green sheet and the internal electrode pattern layer deteriorates, and there is a tendency that many cracks are generated in the sintered body.

  When a gum rosin, rosin glycerin ester or alicyclic petroleum resin is used as a tackifier contained in the internal electrode paste for forming the internal electrode pattern, the degree of butyralization of the polyvinyl butyral resin is preferably 55 mol. % Exceeding 77 mol%, more preferably 60 to 70 mol%. If the degree of butyralization is too small or too large, the adhesiveness (stackability) between the green sheet and the internal electrode pattern layer tends to deteriorate due to a change in the characteristics of the polyvinyl butyral resin. The degree of butyralization is a value determined by a butyralization reaction between polyvinyl alcohol and butyraldehyde. Further, the amount of residual acetyl groups in the polyvinyl butyral resin is preferably less than 6%, more preferably 3% or less.

  In the present invention, when terpene phenol is used as the tackifier contained in the internal electrode paste for forming the internal electrode pattern, the degree of butyralization of the polyvinyl butyral resin is preferably more than 55 mol% and less than 63 mol%. is there. If the degree of butyralization is too small or too large, the adhesiveness (stackability) between the green sheet and the internal electrode pattern layer tends to deteriorate due to a change in the characteristics of the polyvinyl butyral resin.

  The organic solvent used for the organic vehicle is not particularly limited, and methyl ethyl ketone, butyl carbitol, acetone, toluene and the like are used.

  Content of each component in a dielectric paste is not specifically limited, For example, a dielectric paste can be prepared so that about 1 to about 50 weight% of solvent may be included.

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

  Examples of the plasticizer include phthalate esters such as dioctyl phthalate and benzylbutyl phthalate, adipic acid, phosphate esters, glycols, and the like. The weight ratio of the plasticizer in the paint when blending the plasticizer is not particularly limited, but is preferably 40 to 70 parts by weight with respect to 100 parts by weight of the 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 and is difficult to handle.

  In this embodiment, since a polyvinyl butyral resin is used as the organic binder in the organic vehicle, the content of the plasticizer in this case is about 25 to about 100 parts by weight with respect to 100 parts by weight of the polyvinyl butyral resin. preferable.

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

Formation of Ceramic Green Sheet (2) Next, using this dielectric paste, a wire bar coater, a doctor blade method or the like is preferably used on a carrier sheet 20 as a support as shown in FIG. Forms a ceramic green sheet 30 with a thickness of about 1 μm or less.

  As the carrier sheet 20, for example, a PET film or the like is used, and a surface on which the ceramic green sheet 30 is formed is preferably subjected to a release treatment (coating with silicone or the like) in order to improve peelability. . Although the thickness of the carrier sheet 20 is not specifically limited, Preferably it is 5-100 micrometers.

  The ceramic green sheet 30 is dried after being formed on the carrier sheet 20. The drying temperature of the ceramic green sheet 30 is preferably 50 to 100 ° C., and the drying time is preferably 1 to 20 minutes.

  The thickness of the ceramic green sheet 30 after drying contracts by 5 to 25% from the thickness before drying. In this embodiment, the thickness of the ceramic green sheet 30 after drying is preferably 0.4 to 1 μm, and more preferably 0.4 to 0.8 μm. This is in order to meet the demand for thinner layers in recent years. If the thickness of the green sheet is too thick, depending on the thickness of the internal electrode pattern layer, the binder resin content per layer increases, and cracks tend to occur after firing.

Preparation of Internal Electrode Paste (3) Next, in order to form the internal electrode pattern layer 40 which will constitute the internal electrode layer 3 shown in FIG. 1 after firing on the surface of the ceramic green sheet, the internal electrode paste Prepare.

  The internal electrode paste is composed of an organic solvent-based paste obtained by kneading a conductor powder 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 an Ni alloy is preferably an alloy of Ni and at least one element selected from Mn, Cr, Co, and Al, and the Ni content in the alloy is preferably 95% by weight 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 a spherical shape or a flake shape, and may be a mixture of these shapes. In addition, when the particle diameter of the conductor powder is usually spherical, the average particle diameter is 0.5 μm or less, preferably about 0.01 to 0.2 μm. This is to realize the thinning more surely.

  The conductor powder is preferably contained in the internal electrode paste in an amount of 30 to 60% by weight, more preferably 40 to 50% by weight.

  The organic vehicle contains an organic binder and a solvent as main components.

  In the present invention, the organic binder has ethyl cellulose and a tackifier, and the tackifier is at least one selected from gum rosin, rosin glycerin ester and alicyclic petroleum resin, preferably gum rosin.

  In particular, when the butyralization degree of the polyvinyl butyral resin contained in the ceramic green sheet is more than 55 mol% and 63 mol% or less, terpene phenol is preferably used as a tackifier.

  In order to give adhesiveness to the green sheet containing the above-described butyral resin having a high degree of polymerization and the internal electrode pattern layer containing ethyl cellulose, it is necessary to select the tackifier. When tackifiers other than these are selected, the green sheet containing the butyral resin having the above-mentioned degree of polymerization and the internal electrode pattern layer containing ethyl cellulose cannot be given tackiness, and the lamination of the sheets It becomes difficult.

  The content of the organic binder is more than 2 parts by weight and less than 9 parts by weight, preferably 3 to 8 parts by weight with respect to 100 parts by weight of the conductor powder. The content ratio of the tackifier to the total content of the organic binder is 5 to 50% by weight, preferably 5 to 50% by weight (excluding 5% by weight), more preferably 10 to 50% by weight (however, 10% by weight is excluded).

  If the content of the organic binder is too small, the viscosity of the internal electrode paste becomes low and screen printing tends to be impossible. Moreover, when there is too much content, the adhesiveness of a sheet | seat will deteriorate and it exists in the tendency for many cracks to generate | occur | produce in a sintered compact.

  When the content ratio of the tackifier with respect to the total content of the organic binder is too small, stacking of sheets tends to be difficult. On the other hand, if the content ratio is too large, the viscosity of the internal electrode paste becomes low and screen printing tends to be impossible.

  The average weight molecular weight (Mw) of ethylcellulose becomes like this. Preferably it is 190,000 or more and less than 250,000, More preferably, it is 190000-230,000. When the average weight molecular weight is too small, the viscosity of the internal electrode paste becomes low and screen printing tends to be impossible. On the other hand, if the average weight molecular weight is too large, the adhesiveness of the sheet is deteriorated and the sintered body tends to have many cracks.

  The content of ethoxyl groups in ethyl cellulose is preferably more than 46.1% by weight and less than 52.0% by weight, more preferably 48.0 to 49.5% by weight. When the content of the ethoxyl group is outside the range of the present invention, the adhesiveness of the sheet is deteriorated and the sintered body tends to generate many cracks.

  As the solvent, in order to prevent the sheet attack phenomenon, a polyvinyl butyral resin contained in the ceramic green sheet is preferably not swelled or dissolved, that is, an incompatible solvent is preferable. Specific examples include α-terpinyl acetate, isobornyl acetate, dihydroterpinyl acetate, dihydroterpinyl methyl ether, terpinyl methyl ether, I-dihydrocarbyl acetate and the like.

  The solvent is contained in the internal electrode paste in an amount of preferably 50 to 150 parts by weight, more preferably 80 to 100 parts by weight with respect to 100 parts by weight of the conductor powder. If the amount of the solvent is too small, the paste viscosity becomes too high, and if it is too much, the paste viscosity becomes too low.

  In the present embodiment, the internal electrode paste further includes a common material that is the same ceramic powder as the ceramic powder included in the dielectric paste. When the internal electrode paste has the co-material, it is possible to alleviate the difference in shrinkage rate during firing between the conductor powder contained in the internal electrode paste and the ceramic powder contained in the green sheet. As a result, generation of cracks in the sintered body can be suppressed. The ceramic powder used as the co-material is preferably contained in the internal electrode paste in an amount of 5 to 50 parts by weight with respect to 100 parts by weight of the conductor powder. If the amount of the co-material is too small, the sintering suppression effect of the conductor powder is lowered, the lineability (continuity) of the internal electrode layer 3 after firing is deteriorated, and the apparent dielectric constant is lowered. On the other hand, when the amount of the co-material is too large, the linearity of the internal electrode layer 3 after firing tends to deteriorate, and the apparent dielectric constant tends to decrease.

  In order to improve adhesion, the internal electrode paste may include a plasticizer. In this case, the plasticizer species and the addition amount may be the same as those of the dielectric paste.

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

Formation of Internal Electrode Pattern Layer (4) Next, as shown in FIG. 2B, an internal electrode pattern layer 40 having a predetermined pattern is formed on the surface of the ceramic green sheet 30 formed on the carrier sheet 20.

  The method for forming the internal electrode pattern layer 40 is not particularly limited as long as the layer can be formed uniformly, but in this embodiment, the screen printing method using the internal electrode paste is used.

  The thickness of the internal electrode pattern layer 40 is preferably 0.4 to 1 μm. If the thickness of the internal electrode pattern layer 40 is too thick, depending on the thickness of the green sheet, the binder resin content per layer increases, and cracks tend to occur after firing. Furthermore, the number of stacked layers must be reduced, and the acquired capacity is reduced, making 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.

  The thickness of the internal electrode pattern layer 40 is in the above range in the current technology, but it is more preferable that the thickness is within a range in which the electrode is not interrupted.

  Thereafter, the internal electrode pattern layer 40 is dried as necessary. The drying temperature is not particularly limited, but is preferably 50 to 120 ° C., and the drying time is preferably 1 to 15 minutes.

Formation of Blank Pattern Layer (5) In this embodiment, after the internal electrode pattern layer 40 having a predetermined pattern is formed on the surface of the ceramic green sheet by the printing method, or before that, the internal electrode shown in FIG. As shown in FIG. 2C, a blank pattern layer 60 having substantially the same thickness as the internal electrode pattern layer 40 is formed in the surface gap (blank pattern portion 50) of the ceramic green sheet 30 on which the pattern layer 40 is not formed. Form. The reason why the thickness of the blank pattern layer 60 is set to be substantially the same as that of the internal electrode pattern layer 40 is that a step is formed unless the thickness is substantially the same, and the influence increases particularly when the number of layers is increased.

  In this embodiment, the blank pattern layer 60 is formed by a screen printing method using an electrode level difference absorbing printing paste.

  The electrode level difference absorbing print paste used in the present embodiment is not particularly limited, but it is preferable in the process to use the dielectric paste prepared above.

  This electrode level difference absorbing print paste is printed on the blank pattern portion 50 between the internal electrode pattern layers 40 shown in FIG. Thereafter, the internal electrode pattern layer 40 and / or the blank pattern layer 60 are dried as necessary. The drying temperature is not particularly limited, but is preferably 50 to 120 ° C., and the drying time is preferably 1 to 15 minutes.

Formation of outer layer (6) In the present embodiment, the outer layer 32 is formed to protect the ceramic green sheet 30 having the inner electrode pattern layer 40 and the blank pattern layer 60 of the predetermined pattern formed on the surface. . In other words, a predetermined number of laminated ceramic green sheets 30 are sandwiched between the outer layers 32. The outer layer 32 has a configuration in which one or more ceramic green sheets on which the internal electrode pattern layer 40 is not formed are laminated.

  Similar to the ceramic green sheet 30, the outer layer green sheet is formed on the carrier sheet 20 using the outer layer dielectric paste. As the dielectric paste for the outer layer, the dielectric paste produced as described above may be used. However, a paste in which the binder type, the amount of binder added, the degree of binder polymerization, and the like are changed may be used.

Lamination Step (7) Next, in the present embodiment, as shown in FIG. 3A, the electrode layer 40 and the blank pattern layer 60 having a predetermined pattern are formed on the surface of the outer layer 32 formed on the carrier sheet 20. The ceramic green sheets 30 formed in the above are laminated while being heated and pressurized, and the carrier sheet 20 is peeled off. And as shown in FIG.3 (B), said process is repeated to the desired number of lamination | stacking, and a green ceramic laminated body is obtained. The pressing temperature is preferably 50 to 100 ° C., and the applied pressure is preferably 5 to 25 MPa.

Green chip production, firing, etc. (8) The obtained green ceramic laminate was cut into a predetermined size to produce a green chip, which was formed through a binder removal process, a firing process, and an annealing process performed as necessary. Then, the external electrode paste is printed or transferred to the capacitor body 10 composed of a sintered body and fired to form the external electrodes 4 and 4, and the multilayer ceramic capacitor 1 is manufactured.

  By the method described in the present embodiment, the thickness of the ceramic green sheet is reduced, and even when the degree of polymerization of polyvinyl butyral contained in the green sheet is high, gum rosin, rosin glycerin ester contained in the internal electrode pattern layer, At least one selected from an alicyclic petroleum resin and terpene phenol is compatible with the green sheet and the internal electrode pattern layer to give adhesiveness. As a result, it is possible to provide the multilayer ceramic capacitor 1 in which the adhesion and lamination properties between the green sheet and the internal electrode pattern layer are improved and cracks after firing are effectively prevented.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the embodiment mentioned above at all, and can be variously modified within the range which does not deviate from the summary of this invention.

  For example, in the above-described embodiment, the multilayer ceramic capacitor is exemplified as the electronic component according to the present invention. However, the electronic component according to the present invention is not limited to the multilayer ceramic capacitor and can be applied to a multilayer ceramic substrate or the like. It is.

  In addition, a predetermined number of laminate units in which a plurality of ceramic green sheets 10a formed by the method according to the present invention and the internal electrode patterns 12 are laminated are formed, and these laminate units are further laminated to form a final structure. A simple laminate may be produced.

  Further, in the above-described embodiment, the method of peeling the carrier sheet after laminating and pressing is employed. However, since the degree of polymerization of the butyral resin contained in the green sheet according to the present invention is high, the ceramic green sheet is You may laminate | stack by the method of peeling from a sheet | seat. Further, the internal electrode pattern layer may be formed by a transfer method.

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

Example 1
Production of Dielectric Paste First, a dielectric paste for forming a ceramic green sheet was produced. First, BaTiO ₃ ceramic powder, polyvinyl butyral resin (PVB) (polymerization degree: 1700) as an organic binder, propyl alcohol, xylene, methyl ethyl ketone, 2-butoxyethyl alcohol as a solvent, and diphthalic acid as a plasticizer 2-Ethylhexyl was prepared. Next, 6 parts by weight of PVB, 150 parts by weight of solvent, and plasticizer are weighed with respect to 100 parts by weight of ceramic powder, and kneaded with a zirconia ball having a diameter of 2 mm in a ball mill for 21 hours to form a slurry and dielectric. A body paste was obtained. The plasticizer was added in an amount of 50 parts by weight with respect to 100 parts by weight of polyvinyl butyral.

Production of Internal Electrode Paste Next, an internal electrode paste for forming the internal electrode pattern layer 40 was produced. First, Ni particles having an average particle diameter of 0.2 μm as a conductor powder, BaTiO ₃ ceramic powder as a co-material, ethyl cellulose, α-terpinyl acetate as a solvent, and a tackifier are prepared. did. Then, 122 parts by weight of α-terpinyl acetate and 6 parts by weight of an organic binder are added to 130 parts by weight of 100 parts by weight of the conductor powder and 30 parts by weight of the co-material, and this is kneaded by a ball mill. And slurried to obtain an internal electrode paste. The organic binder is composed of ethyl cellulose and a tackifier shown in Table 1. Moreover, the tackifier shown in Table 1 is contained at an addition ratio of 40 wt% with respect to the organic binder amount of 100 wt%. That is, 3.6 parts by weight of ethyl cellulose is included with respect to 100 parts by weight of the conductor powder, and 2.4 parts by weight of the tackifier shown in Table 1 is included.

Evaluation of internal electrode paste Viscosity and maximum normal stress of the obtained internal electrode paste were measured. The viscosity was measured at a shear rate of 500 s ^-1 . In the measurement, a parallel plate viscometer was used. The viscosity was set to be 1.0 Pa · s or more. The results are shown in Table 1.

  The maximum normal stress was measured using a viscoelasticity measuring device (rheometer) capable of measuring normal stress. A pair of parallel plates (circular) having a diameter of 40 mm, a distance between the plates of 300 μm, a temperature of the internal electrode paste of 25 ° C., and a shear rate of 1000 to 10,000 [1 / s] with respect to the internal electrode paste The normal stress of the paste was measured. A maximum normal stress of 0.2 N or more was considered good. The results are shown in Table 1.

Production of Multilayer Ceramic Chip Capacitor Sample Next, using the dielectric paste produced above and the internal electrode paste, a multilayer ceramic chip capacitor 1 shown in FIG. 1 was further produced as follows.

  First, a dielectric sheet was applied with a predetermined thickness on a surface of a PET film as a support subjected to a release treatment using a wire bar coater, and dried to produce a green sheet having a thickness of 0.6 μm.

  Next, a screen pattern using an internal electrode paste is formed on the obtained green sheet so that the screen pattern is a strip of 4.0 × 1.2 mm and the thickness after drying is 0.6 μm. An internal electrode pattern layer 40 (see FIG. 2B) was formed.

  Thereafter, a blank pattern portion 50 on the green sheet where the internal electrode pattern layer 40 is not formed (see FIG. 2B) is substantially the same as the internal electrode pattern layer 40 by screen printing using a dielectric paste. A blank pattern layer 60 (see FIG. 2C) having a thickness was formed, and a ceramic green sheet 30 having the internal electrode pattern film 40 and the blank pattern layer 60 as shown in FIG. 2C was obtained. In this example, this ceramic green sheet 30 was used as a green sheet, and a plurality of these were prepared.

  Next, a dielectric paste for forming an outer layer green sheet was prepared in the same manner as the dielectric paste prepared above except that the polymerization degree of the polyvinyl butyral resin was 1500. This dielectric paste was applied on the surface of the PET film that had been subjected to the mold release treatment to a predetermined thickness using a wire bar coater and dried to produce an outer layer green sheet having a thickness of 12 μm.

  Eight green sheets for the outer layer were prepared, and these were laminated by thermocompression bonding to form an outer layer having a thickness of 96 μm.

  On the obtained outer layer, the ceramic green sheet in which the internal electrode pattern layer and the blank pattern layer were formed was pressure-bonded under the conditions of a temperature of 75 ° C. and a pressure of 12 MPa, and the PET film was peeled off (see FIG. 3A). ). This process was repeated to stack a desired number of ceramic green sheets on which the internal electrode pattern layer and the blank pattern layer were formed (see FIG. 3B). Thereafter, the outer layer having a thickness of 96 μm was further formed by thermocompression to obtain a green ceramic laminate.

  When laminating the ceramic green sheet on which the internal electrode pattern layer and the blank pattern layer are formed, the internal electrode portion is shifted by half in the longitudinal direction of the strip shape with respect to the ceramic green sheet that has been just laminated, Positioning was performed accurately so that the electrode portions overlapped in the direction.

Evaluation of green ceramic laminate The peel strength and adhesive strength of the support (PET film) were measured for the obtained green ceramic laminate.

  The peel strength of the support was measured on five samples of the green ceramic laminate, and the average value was obtained. In the measurement of peel strength, one end of a PET film having a length of 5 cm in the laminate is pulled up at a rate of 1000 mm / min in a direction (vertical direction) 90 ° with respect to the laminate surface of the laminate, When peeling from the laminate unit, the force (mN / cm) acting on the PET film was measured. This force was defined as a support 90 ° peel strength. By reducing the peel strength, the PET film can be favorably peeled from the laminate, and breakage of the laminate during peeling can be effectively prevented. Therefore, the peel strength is preferably as low as possible, and 20 mN / cm or less is considered good. The results are shown in Table 1.

The adhesion of the green ceramic laminate was determined by converting the strength value when the laminate was pulled and peeled using an Instron 5543 tensile tester to the adhesive strength of the laminate at 1 cm square. The sheet adhesion was determined to be 25 N / cm ² or more. The results are shown in Table 1.

  In addition, said evaluation was performed in the state which does not form one outer layer of a green ceramic laminated body. That is, the peel strength from the support and the adhesive strength of the green sheet were evaluated on the ceramic green sheet on which the internal electrode pattern layer and the blank pattern layer were formed, not on the green sheet forming the outer layer.

Next, after the obtained green ceramic laminate was cut into a predetermined size, binder removal, 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.

  The size of the obtained sintered body is 1.6 mm long × 0.8 mm wide × 0.8 mm high, and the thickness of the dielectric layer 2 sandwiched between the pair of internal electrode layers is about 0.6 μm. The thickness of layer 3 was 0.6 μm.

Evaluation of Sintered Body The obtained sintered body was cut and the cross section was observed to evaluate the presence or absence of cracks. This was done for 10 capacitor samples. Of the 10 samples, the number of samples in which cracks are observed is preferably 3 or less, and more preferably no cracks are observed in all 10 samples. The results are shown in Table 1.

As shown in Table 1, when the tackifier is one of gum rosin, rosin glycerin ester or alicyclic petroleum resin (sample numbers 1 to 3), any of internal electrode paste, laminate, and sintered body Good results have also been obtained for.
On the other hand, when the tackifier is polymerized rosin or terpene phenol (sample numbers 4 and 5), the adhesiveness of the laminate is inferior, and in particular, the degree of butyralization of the polyvinyl butyral resin contained in the ceramic green sheet is 65. When the tackifier contained in the internal electrode paste was terpene phenol (Sample No. 5), it could not be laminated.

Example 2
A dielectric paste and an internal electrode paste were prepared in the same manner as Sample No. 1 except that the addition ratio of the tackifier, the content of the organic binder, and the polymerization degree of polyvinyl butyral were set to the values shown in Table 2. A ceramic laminate and a sintered body were produced and evaluated in the same manner as in Example 1. The results are shown in Table 2.

  From Table 2, when the addition ratio of the tackifier was 0, that is, when the gum rosin was not added to the internal electrode paste (Sample No. 6), it was inferior in adhesiveness and thus could not be laminated. On the other hand, when the addition ratio of the tackifier was larger than the range of the present invention (Sample No. 11), the viscosity of the internal electrode paste was low and screen printing was impossible. For sample No. 6, there was a crack in the sintered body.

  Further, when the content of the organic binder was less than the range of the present invention (Sample No. 12), the internal electrode paste had a low viscosity, and screen printing was impossible. On the other hand, when the content of the organic binder is larger than the range of the present invention (Sample No. 16), the amount of resin is increased, so that cracks occurred in the sintered body.

  Furthermore, when the degree of polymerization of polyvinyl butyral was outside the range of the present invention (sample numbers 17 and 21), the laminate had poor adhesion, and cracks were also observed in the sintered body.

Example 3
A dielectric paste and an internal electrode paste were prepared in the same manner as Sample No. 1 except that the weight average molecular weight and ethoxyl group content of ethyl cellulose, the content of polyvinyl butyral and the degree of butyralization were the values shown in Table 3. Further, a green ceramic laminate and a sintered body were produced and evaluated in the same manner as in Example 1. The results are shown in Table 3.

  From Table 3, when the weight average molecular weight of ethyl cellulose is smaller than the preferred range of the present invention (Sample No. 22), the viscosity of the internal electrode paste was low and screen printing was impossible. On the other hand, when the weight average molecular weight of ethyl cellulose is larger than the preferred range of the present invention (Sample No. 25), the adhesion of the laminate was inferior, and cracks were also observed in the sintered body.

Further, when the ethoxyl group content of ethyl cellulose is outside the preferred range of the present invention (Sample Nos. 26 and 29), the properties of ethyl cellulose change, resulting in poor adhesion of the laminate, and even in the sintered body. Cracks were observed.
Moreover, when content of polyvinyl butyral resin is smaller than the preferable range of this invention (sample number 30), since content is small, it is inferior to the adhesiveness of a laminated body, and the crack was observed also in the sintered compact. . On the other hand, when the content of the polyvinyl butyral resin is larger than the preferable range of the present invention (Sample No. 35), on the contrary, the amount of the resin is too large, so that cracks occurred in the sintered body.

  Furthermore, when the butyralization degree of the polyvinyl butyral resin is outside the preferable range of the present invention when the tackifier is gum rosin (sample numbers 36 and 37), the characteristics of the polyvinyl butyral are changed, and the lamination The adhesiveness of the body was poor, and cracks were also observed in the sintered body.

  In addition, when the tackifier is terpene phenol, when the degree of butyralization of the polyvinyl butyral resin is outside the preferred range of the present invention (sample numbers 41 and 44), the properties of polyvinyl butyral change, The adhesion of the laminate was inferior, and cracks were observed in the sintered body.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. FIGS. 2A to 2C are cross-sectional views of relevant parts showing a part of the manufacturing process of the multilayer ceramic capacitor shown in FIG. 3 (A) and 3 (B) are cross-sectional views of the main part showing the continuation of the manufacturing process shown in FIGS. 2 (A) to 2 (C).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 10 ... Capacitor body 2 ... Dielectric layer 3 ... Internal electrode layer 4 ... External electrode 20 ... Carrier sheet 30 ... Ceramic green sheet 32 ... Outer layer 40 ... Internal electrode pattern layer 50 ... Blank pattern part 60 ... Blank Pattern layer

Claims (6)

A method for producing a multilayer ceramic electronic component comprising a step of alternately stacking a plurality of ceramic green sheets containing ceramic powder and butyral resin and a predetermined pattern of internal electrode pattern layers to obtain a green ceramic laminate,
The degree of polymerization of the butyral resin is 1000-2400,
The internal electrode paste for forming the internal electrode pattern layer has a conductor powder and an organic binder,
The organic binder has ethyl cellulose and at least one selected from gum rosin, rosin glycerin ester and alicyclic petroleum resin as a tackifier,
The organic binder is contained in an amount of more than 2 parts by weight and less than 9 parts by weight with respect to 100 parts by weight of the conductor powder, and the content ratio of the tackifier with respect to the content of the organic binder is 5 to 50% by weight. A method for producing a multilayer ceramic electronic component.   The method for manufacturing a multilayer ceramic electronic component according to claim 1, wherein the butyral resin is contained in an amount of more than 5 parts by weight and less than 10 parts by weight with respect to 100 parts by weight of the ceramic powder.   The method for producing a multilayer ceramic electronic component according to claim 1 or 2, wherein the ethyl cellulose has a weight average molecular weight of 190,000 or more and less than 250,000.   The method for producing a multilayer ceramic electronic component according to claim 1, wherein the ethylcellulose has an ethoxyl group content of more than 46.1% by weight and less than 52.0% by weight.   The method for producing a multilayer ceramic electronic component according to claim 1, wherein the butyral resin has a butyralization degree of more than 55 mol% and less than 77 mol%. A method for producing a multilayer ceramic electronic component comprising a step of alternately stacking a plurality of ceramic green sheets containing ceramic powder and butyral resin and a predetermined pattern of internal electrode pattern layers to obtain a green ceramic laminate,
The degree of polymerization of the butyral resin is 1000-2400,
The butyral degree of butyral resin is more than 55 mol% and 63 mol% or less,
The internal electrode paste for forming the internal electrode pattern layer has a conductor powder and an organic binder,
The organic binder has ethyl cellulose and terpene phenol as a tackifier,
The organic binder is contained in an amount of more than 2 parts by weight and less than 9 parts by weight with respect to 100 parts by weight of the conductor powder, and the content ratio of the tackifier with respect to the content of the organic binder is 5 to 50% by weight. A method for producing a multilayer ceramic electronic component.

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