JP2007081339A - Conductive paste, laminated ceramic electronic component and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive paste used for forming an internal electrode of a laminated ceramic electronic component and capable of effectively preventing a seat attack even in the case where a thickness of a ceramic green seat is formed into a thin layer. <P>SOLUTION: A conductive paste is provided, which is used for forming an internal electrode of a laminated ceramic electronic component, containing conductive powders and an organic vehicle, wherein an organic binder in the organic vehicle is mainly composed of ethyl cellulose, and a solvent in the organic vehicle is mainly composed of one or more elements selected from isobornyl propionate, isobornyl butyrate, and isobornyl isobutyrete. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conductive paste used for forming internal electrodes of a multilayer ceramic electronic component, a multilayer ceramic electronic component manufactured using the paste, and a method for manufacturing the electronic component.

  In recent years, electronic devices are becoming lighter, thinner, and smaller. Along with this, further miniaturization and higher capacity have been promoted in the multilayer ceramic electronic parts used in the electronic devices.

  The most effective method for reducing the size and increasing the capacity of a multilayer ceramic capacitor as an example of a multilayer ceramic electronic component is to make both the internal electrode and the dielectric layer as thin as possible (thinning), and to Is laminated as much as possible (multilayering).

  A multilayer ceramic capacitor is a ceramic green sheet mainly composed of a ceramic powder represented by barium titanate and a binder, and a conductive paste for forming internal electrodes is printed in a predetermined pattern and laminated, and then fired simultaneously. It is manufactured by integrally sintering and finally forming external electrodes.

  As the conductive paste for forming the internal electrode, a paste obtained by dispersing conductive powder in an organic vehicle in which an organic binder is dissolved in a solvent is used. As the organic binder in the organic vehicle, for example, ethyl cellulose or the like has been used, and as the solvent in the organic vehicle, terpineol or the like has been used.

  However, if a conductive paste using terpineol as a solvent is printed on a ceramic green sheet, it may cause problems such as blurring, and a thin electrode pattern with a predetermined thickness can be formed. There wasn't.

  In addition, when a conductive paste using terpineol as a solvent is used in combination with a ceramic green sheet using butyral resin as an organic binder, the solvent in the conductive paste causes the organic binder in the ceramic green sheet to swell or dissolve. The so-called “sheet attack” phenomenon occurs.

  Such a sheet attack phenomenon is not a practical problem as long as the ceramic green sheet is relatively thick. However, when the thickness of the ceramic green sheet is as thin as 5 μm or less, for example, if a sheet attack phenomenon occurs, the ceramic green sheet peels off when the ceramic green sheet is peeled off from a carrier sheet such as a PET film after printing the conductive paste. It becomes difficult. 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 laminated body cannot be obtained, the final multilayer ceramic electronic component may have short-circuit failure, breakdown voltage failure (IR degradation), or delamination phenomenon (delamination) between the dielectric layer and the internal electrode layer. Occurred, leading to a decrease in yield.

  Therefore, in recent years, several measures for improving the seat attack phenomenon have been proposed. For example, Patent Documents 1 and 2 propose that a solvent having a relatively low compatibility with butyral is used as a solvent for a conductive paste for forming an internal electrode. Specifically, Patent Document 1 proposes a conductive paste using dihydroterpineol, and Patent Document 2 proposes a conductive paste using dihydroterpinyl acetate.

  However, even when these dihydroterpineols and dihydroterpinyl acetates are used as a solvent, not a few sheet attack phenomena occur, resulting in variations in the thickness of the ceramic green sheets. Due to this thickness variation, there has been a problem that short-circuit failure and withstand voltage failure (IR deterioration) are worsened, and delamination occurs. For this reason, the conventional conductive paste has a limit in further reducing the size and capacity of the multilayer ceramic capacitor.

Japanese Patent Laid-Open No. 9-17687 Japanese Patent No. 2976268

  An object of the present invention is used to form an internal electrode of a multilayer ceramic electronic component, and even when the thickness of the ceramic green sheet is reduced, a conductive paste that can effectively prevent sheet attack; A multilayer ceramic electronic component manufactured using this conductive paste, having a low short-circuit defect rate, a high withstand voltage, and effectively preventing delamination, and a method of manufacturing the electronic component Is to provide.

  The present inventors have successfully dissolved ethyl cellulose contained as a binder in the conductive paste by using a specific solvent as a solvent to be contained in the conductive paste, and the thickness of the ceramic green sheet. The present inventors have found that sheet attack can be effectively prevented even when the layer is made thinner, and the present invention has been completed. Furthermore, it has also been found that by using this specific solvent, as a secondary effect, even when used in a mode mixed with a predetermined amount of terpineol, the effect of preventing sheet attack is sufficiently exhibited.

That is, according to the present invention, a conductive paste used to form an internal electrode of a multilayer ceramic electronic component,
Including conductive powder and organic vehicle;
The organic binder in the organic vehicle is mainly composed of ethyl cellulose,
There is provided a conductive paste characterized in that a solvent in the organic vehicle is mainly composed of one or more selected from isobornyl propionate, isobornyl butyrate and isobornyl isobutyrate.

  Preferably, the solvent in the organic vehicle is contained in an amount of 50 to 200 parts by weight with respect to 100 parts by weight of the conductive powder.

  Preferably, the organic binder in the organic vehicle is contained in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of the conductive powder.

  In the conductive paste according to the present invention, the conductive powder may be any powder that can withstand the firing temperature and atmosphere when fired simultaneously with the ceramic green sheet. For example, when the multilayer ceramic electronic component is a multilayer ceramic capacitor, a simple substance such as Ag, Pd, or Ni, a mixture thereof, or an alloy powder can be used, and it is particularly preferable that Ni or Ni alloy is the main component. When the multilayer ceramic electronic component is a multilayer ceramic substrate, a single substance such as Ag, Pd, or Cu, a mixture thereof, or an alloy powder can be used.

  Preferably, the solvent in the organic vehicle contains at least one selected from isobornyl butyrate and isobornyl isobutyrate and terpineol, and the content of the terpineol in the solvent is It is more than 0% by weight and 20% by weight or less with respect to 100% by weight of the whole solvent.

  Alternatively, the solvent in the organic vehicle contains isobornyl propionate and terpineol, and the content of the terpineol in the solvent is less than 0% by weight with respect to 100% by weight of the whole solvent. It is often 10% by weight or less.

  The conductive paste according to the present invention may contain additives such as a plasticizer and a dispersant as necessary.

According to the present invention, a green ceramic in which a plurality of ceramic green sheets having a thickness of 5 μm or less containing a butyral resin and electrode layers formed in a predetermined pattern using any one of the above conductive pastes are alternately stacked. Manufactured using laminates,
A multilayer ceramic electronic component having an internal electrode layer and a dielectric layer having a thickness of 3 μm or less is provided.

  Furthermore, according to the present invention, a green ceramic in which a plurality of ceramic green sheets having a thickness of 5 μm or less containing a butyral resin and electrode layers formed in a predetermined pattern using any one of the conductive pastes are alternately stacked. A method for manufacturing a multilayer ceramic electronic component for firing a multilayer body is provided.

  In the present invention, isobornyl propionate, isobornyl butyrate and isobornyl isobutyrate used as the solvent for the conductive paste do not dissolve or swell the butyral resin contained as an organic binder in the ceramic green sheet (incompatible). . For this reason, sheet attack can be effectively prevented by using the conductive paste using these solvents. For this reason, even when the thickness of the ceramic green sheet is reduced to, for example, 5 μm or less, the peelability of the ceramic green sheet is improved when the ceramic green sheet is peeled off from the carrier sheet such as a PET film after printing the conductive paste. In addition, the generation of wrinkles, holes, cracks, etc. in the ceramic green sheet can be effectively suppressed. That is, even if the ceramic green sheet is made thinner than before, the sheet attack phenomenon does not occur. As a result, even when a very thin ceramic green sheet having a thickness of 5 μm or less is applied, a normal laminate can be obtained. In the final multilayer ceramic electronic component, short circuit failure, withstand voltage failure (IR degradation), dielectric layer The possibility of causing delamination between the electrode layer and the internal electrode layer is reduced.

  Further, isobornyl propionate, isobornyl butyrate and isobornyl isobutyrate have a property of extremely low compatibility with butyral resin contained as an organic binder in the ceramic green sheet. For this reason, even when used in combination with terpineol as an example of a solvent having high compatibility with butyral resin, the content of terpineol is not more than a predetermined amount (for example, 10 wt.% When isobornyl propionate is used). % Or less, and when isobonyl butyrate or isobornyl isobutyrate is used, the effect of preventing sheet attack as described above can be sufficiently exhibited. Therefore, even when products using these isobornyl propionate, isobornyl butyrate and isobornyl isobutyrate as a solvent are manufactured using the same manufacturing equipment as products using terpineol as a solvent, terpineol Since the problem of sheet attack due to the mixing of the above does not occur, the manufacturing equipment can be shared, and as a result, a reduction in manufacturing cost can be expected.

  Furthermore, terpineol is highly compatible with ethyl cellulose used as a binder for conductive paste. For this reason, the addition of a predetermined amount of terpineol to the conductive paste has the property of improving the stability of the conductive paste (for example, reducing the change over time). Therefore, in the present invention, when isobornyl propionate is used, terpineol is in the range of 10% by weight or less, and when isobonyl butyrate or isobornyl isobutyrate is used, terpineol is added. By containing it in the range of 20% by weight or less, in addition to the sheet attack preventing effect, the effect of improving the stability of the conductive paste can be obtained.

From the above, the conductive paste of the present invention is extremely useful for reducing the size and increasing the capacity of the final multilayer ceramic electronic component.
That is, according to the present invention, a conductive paste that is used to form an internal electrode of a multilayer ceramic electronic component and does not cause a sheet attack, and manufactured using this conductive paste, has a low short-circuit defect rate and high A multilayer ceramic electronic component having a withstand voltage and effectively preventing delamination, and a method for manufacturing the multilayer ceramic electronic part can be provided.

  The multilayer ceramic electronic component 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.
FIG. 2 (A) and FIG. 2 (B) are photomicrographs showing the compatibility between isobonylpropionate and ceramic green sheets,
FIG. 3 (A) to FIG. 3 (C) are photomicrographs showing the compatibility of isobonyl isobutyrate and the ceramic green sheet,
FIG. 4A is a photomicrograph showing the compatibility between terpineol and the ceramic green sheet, and FIG. 4B is a photomicrograph showing the compatibility between dihydroterpineol and the ceramic green sheet.

  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, which will be described later, and the material thereof is not particularly limited. For example, the dielectric layer 2 is made of a dielectric material such as calcium titanate, strontium titanate and / or barium titanate. . In this embodiment, the thickness of the dielectric layer 2 is preferably 3 μm or less, more preferably 2 μm or less.

  The internal electrode layer 3 is formed by firing a conductive paste having a predetermined pattern which will be described later. The thickness of the internal electrode layer 3 is preferably reduced to 2 μm or less, more 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 this embodiment, the dielectric paste is composed of an organic solvent-based paste obtained by kneading ceramic powder (dielectric material) and an organic vehicle.

  The ceramic powder can be appropriately selected from various compounds to be complex oxides or oxides, such as carbonates, nitrates, hydroxides, organometallic compounds, and the like, and can be used as a mixture. The ceramic powder is usually used as a powder having an average particle size of 0.4 μm or less, preferably about 0.1 to 3.0 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, polyvinyl butyral is used as the organic binder used in the organic vehicle. The degree of polymerization of the polyvinyl butyral is preferably 300 to 2400, more preferably 500 to 2000. The degree of butyralization of the resin is preferably 50 to 81.6%, more preferably 63 to 80%, and the amount of residual acetyl groups is preferably less than 6%, more preferably 3% or less.

  The organic solvent used in the organic vehicle is not particularly limited, and terpineol, 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.

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

Formation of ceramic green sheet (2) Next, using this dielectric paste, it is preferably 0.5 to 30 μm, more preferably 0.5 to 10 μm, still more preferably on the carrier sheet by a doctor blade method or the like. A ceramic green sheet is formed with a thickness of about 0.5 to 5 μm. The ceramic green sheet becomes the dielectric layer 2 shown in FIG. 1 after firing.

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

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

  The thickness of the ceramic green sheet after drying shrinks to a thickness of 5 to 25% compared with that before drying. In this embodiment, the thickness of the ceramic green sheet after drying is 5 μm or less, preferably 3 μm or less, and more preferably 1.5 μm or less. This is in order to meet the demand for thinner layers in recent years.

Formation of Electrode Layer (3) Next, an electrode layer (internal electrode pattern) having a predetermined pattern to be the internal electrode layer 3 shown in FIG. 1 is formed on the surface of the ceramic green sheet formed on the carrier sheet.

  The thickness of the electrode layer is 2 μm or less, preferably 0.5 to 1.5 μm. If the thickness of the electrode layer is too thick, the number of stacked layers must be reduced, the acquired capacity is reduced, and it is 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 electrode layer is in the above range in the current technology, but it is more desirable that the thickness of the electrode layer is as thin as possible without causing electrode breaks.

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

  The conductive paste used in the present embodiment contains a conductive powder and an organic vehicle.

  Although it does not specifically limit as electroconductive powder, It is preferable to comprise by 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 conductive powder is not particularly limited in shape, such as spherical or flake shaped, and may be a mixture of these shapes. The particle diameter of the conductive powder is usually 0.5 mm or less, preferably about 0.01 to 0.4 μm in the case of a spherical shape. This is to realize the thinning more surely.

  The conductive powder is preferably contained in the conductive paste at 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.

  The organic binder is mainly composed of ethyl cellulose in this embodiment. The content of ethyl cellulose in the organic binder is preferably 95% by weight or more, and more preferably 100% by weight. A resin that can be used in combination with ethyl cellulose, although in a very small amount, includes an acrylic resin.

  The organic binder is preferably contained in the conductive paste in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of the conductive powder. If the amount of the binder is too small, the film strength after printing tends to decrease. If the amount is too large, the metal filling density of the electrode pattern before firing decreases, and the smoothness of the internal electrode formed after firing is maintained. I can't.

  The solvent is mainly composed of at least one selected from isobornyl propionate, isobornyl butyrate and isobornyl isobutyrete. When isobonyl propionate is used, these contents in the solvent are preferably 90% by weight or more, more preferably 95% by weight, and still more preferably 100% by weight with respect to 100% by weight of the whole solvent. %. Alternatively, when isobornyl butyrate or isobornyl isobutyrate is used, it is preferably 80% by weight or more, more preferably 90% by weight, and further preferably 100% by weight. By increasing the contents of these isobornyl propionate, isobornyl butyrate and isobornyl isobutyrate, the effect of preventing sheet attack can be improved.

  In addition to these isobornyl propionate, isobornyl butyrate and isobornyl isobutyrate, other solvents may be used in combination. Solvents that can be used in combination include terpineol, dihydroterpineol, dihydroterpinyl acetate, and the like. Among the solvents used in combination, the compatibility with ethyl cellulose as a binder is high, so that the conductive paste can be stabilized (for example, the change with time can be reduced). Turpineol is particularly preferable.

  When isobonylpropionate and terpineol are used in combination, the amount of terpineol added is preferably more than 0% by weight and less than 10% by weight, more preferably 2%, based on 100% by weight of the total solvent. It should be 8% by weight or more. Alternatively, when isobonyl butyrate or isobornyl isobutyrate is used in combination with terpineol, the amount of terpineol added is preferably more than 0% by weight and 20% by weight with respect to 100% by weight of the whole solvent. % Or less, more preferably 4 wt% or more and 16 wt% or less.

  Isobonyl propionate, isobornyl butyrate and isobornyl isobutyrate used in the present embodiment have a property of extremely low compatibility with a butyral resin contained as an organic binder in a ceramic green sheet. For this reason, not only when these isobornyl propionates, isobornyl butyrate and isobornyl isobutyrate are used alone, but also when used in combination with terpineol having the property of easily dissolving or swelling the butyral resin. In addition, dissolution or swelling of the butyral resin can be effectively prevented. That is, the sheet attack can be effectively prevented.

  The solvent is preferably contained in the conductive paste in an amount of 50 to 200 parts by weight, more preferably 80 to 100 parts by weight with respect to 100 parts by weight of the conductive 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.

  The total content of the organic binder and the solvent in the organic vehicle is preferably 95% by weight or more, and more preferably 100% by weight. There are plasticizers, leveling agents and the like that can be contained in an organic vehicle together with an organic binder and a solvent, although only in a very small amount.

  The conductive paste may contain the same ceramic powder as the ceramic powder contained in the dielectric paste as a co-material. The common material has an effect of suppressing the sintering of the conductive powder in the firing process. The ceramic powder (co-material) is preferably contained in the conductive paste in an amount of 5 to 30 parts by weight with respect to 100 parts by weight of the conductive powder. If the amount of the co-material is too small, the sintering suppressing effect of the conductive powder is lowered, the lineability (continuity) of the internal electrode is deteriorated, and the apparent dielectric constant is lowered. On the other hand, if the amount of the co-material is too large, the lineability of the internal electrode tends to deteriorate and the apparent dielectric constant tends to decrease.

  In order to improve adhesion, the conductive paste may contain a plasticizer. Examples of the plasticizer include phthalic acid esters such as benzylbutyl phthalate (BBP), adipic acid, phosphoric acid esters, glycols, and the like. In the present embodiment, preferably, dioctyl adipate (DOA), butyl butylene glycol phthalate (BPBG), didodecyl phthalate (DDP), dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), dioctyl phthalate ( DOP), dibutyl sebacate and the like are used. Of these, dioctyl phthalate (DOP) is particularly preferable. The plasticizer is contained in an amount of preferably 25 to 150 parts by weight, more preferably 25 to 100 parts by weight with respect to 100 parts by weight of the organic binder in the organic vehicle. By adding the plasticizer, the adhesive force of the electrode layer formed using the paste is increased, and the adhesive force between the electrode layer and the ceramic green sheet is improved. In order to obtain such an effect, the amount of the plasticizer added is preferably 25 parts by weight or more. However, if the addition amount exceeds 150 parts by weight, it is not preferable because excess plasticizer oozes out from the electrode layer formed using the paste.

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

Preparation of Green Chip, baking, etc. (4) Next, above that, by stacking a plurality of ceramic green sheets on which the electrode paste layer is formed on the surface of the predetermined pattern, to produce a green chip and subjected to binder removal step, The external electrodes 4 and 4 are formed by printing or transferring the external electrode paste onto the capacitor body 10 composed of a sintered body, which is formed through a firing process and an annealing process performed as necessary, and firing. Thus, the multilayer ceramic capacitor 1 is manufactured.

Other Embodiments The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. it can.

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

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

Example 1
First, a dielectric paste for forming a ceramic green sheet was produced.

Preparation of Dielectric Paste BaTiO ₃ -based ceramic powder, polyvinyl butyral (PVB) as an organic binder, and methanol as a solvent were prepared. Next, 10 parts by weight of an organic binder and 150 parts by weight of a solvent were weighed with respect to 100 parts by weight of the ceramic powder, kneaded with a ball mill, and slurried to obtain a dielectric paste.

The dielectric paste by a doctor blade method on making PET film of the ceramic green sheet was coated with a predetermined thickness, followed by drying the thickness after drying to form a 1μm ceramic green sheet.

Compatibility test between solvent and ceramic green sheet Next, each of the solvents shown below was dropped on the ceramic green sheet prepared above using a pipette, and the surface of the ceramic green sheet after dropping was observed with a microscope. .
As the solvent, each of the solvents shown in Table 1 below was used, and micrographs of the surface of the ceramic green sheet after each solvent was dropped are shown in the respective drawings described in Table 1. In Table 1, the ratio of each solvent is shown by weight.

  From FIG. 4 (A) and FIG. 4 (B), when terpineol (FIG. 4 (A)) and dihydroterpineol (FIG. 4 (B)) are dropped on the ceramic green sheet, the ceramic green sheet swells. As a result, the surface of the ceramic green sheet wavy. 4A and 4B are photographs taken such that the lower right side of each photograph is the center of the droplet. That is, each photograph is a photograph of the upper left portion as viewed from the center of the droplet, and the upper left curved portion in FIGS. 4 (A) and 4 (B) is the outer edge portion of the droplet (specifically, Specifically, a portion swollen by the outer edge of the droplet) is shown.

  On the other hand, from FIG. 2 (A) and FIG. 2 (B), when isobornyl propionate is used as a solvent, only when isobonyl propionate is dropped (FIG. 2 (A)). In addition, even when 10% by weight of terpineol was added (FIG. 2B), it can be confirmed that the ceramic green sheet does not swell. Similarly, from FIG. 3 (A) to FIG. 3 (C), not only when isobornyl isobutyrate is dropped but also when isobornyl isobutyrate is used as the solvent (FIG. 3 (A)). It can be confirmed that the ceramic green sheet does not swell even when terpineol is added at 10 wt% and 20 wt%, respectively (FIGS. 3B and 3C).

  From the above results, isobonyl propionate and isobonyl isobutyrate have extremely low compatibility with butyral resin as an organic binder used for ceramic green sheets, even when terpineol is contained. It can be confirmed that the attack can be effectively prevented. This tendency was the same even when isobonyl butyrate was used.

Example 2
Production of Conductive Paste An organic vehicle for producing a conductive paste was prepared by the following method.

  That is, first, ethyl cellulose as an organic binder and each solvent shown in Table 2 were prepared. Next, 10 parts by weight of ethylcellulose was dissolved in 100 parts by weight of the solvent to prepare an organic vehicle.

  Next, Ni particles having an average particle diameter of 0.2 μm as a conductive powder were prepared, and 30 to 70 parts by weight of the organic vehicle prepared above was added to 100 parts by weight of the conductive powder. The mixture was kneaded to form a slurry to obtain a conductive paste.

Preparation of Test Sample A ceramic green sheet having a thickness of 1 μm was formed by applying the dielectric paste prepared in Example 1 to a predetermined thickness on a PET film by a doctor blade method and drying it.

  Next, on the obtained ceramic green sheet, among the conductive pastes produced above, isobonyl propionate, isobornyl butyrate, and isobornyl isobutyrate, which are examples of the present invention, are used. A ceramic green sheet (test sample) having an electrode pattern with a thickness of about 1.0 μm, formed in a predetermined pattern by screen printing using the conductive paste used (sample numbers 4, 5 and 6 in Table 2) Got.

Evaluation of Test Sample Using the obtained test sample, “presence / absence of sheet attack” and “peelability of PET film from ceramic green sheet” were evaluated.

  “Presence / absence of sheet attack” was performed by visually observing the surface of the ceramic green sheet opposite to the electrode pattern side (the surface in contact with the PET film), and confirming the degree of dissolution of the ceramic green sheet by the degree of deformation and hue. . As a result, dissolution of the ceramic green sheet could not be observed.

  The “peelability of the PET film from the ceramic green sheet” was measured by measuring the peel strength when peeling the PET film from the test sample. The peel strength is measured by attaching a load cell to the end of the 9cm x 20cm ceramic green sheet with PET (the margin that creates the trigger for peeling) with adhesive tape and measuring the load (load) while moving it upward. It was. As a result, the peel strength was an appropriate value of 5.0 gf or less. Thereby, while maintaining the required holding force with respect to a ceramic green sheet, the efficiency of peeling work can be expected.

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

  First, a dielectric paste was applied to a PET film with a predetermined thickness by a doctor blade method and dried to form a ceramic green sheet having a thickness of 1 μm after drying. In this example, this ceramic green sheet was used as the first green sheet, and a plurality of these were prepared.

  Next, a conductive paste was formed in a predetermined pattern on the obtained first green sheet by a screen printing method to obtain a ceramic green sheet having an electrode pattern with a thickness of about 1 μm. In this example, this ceramic green sheet was used as the second green sheet, and a plurality of these were prepared.

Next, the first green sheets were laminated to a thickness of 150 μm to form a ceramic green sheet group. On this ceramic green sheet group, 250 second green sheets were laminated. Further, a ceramic green sheet group composed of a plurality of first green sheets similar to the above is laminated and formed thereon, and heated and pressurized under the conditions of a temperature of 70 ° C. and a pressure of 1.5 ton / cm ² to produce a green ceramic. A laminate was obtained.

  Next, after cutting the obtained laminated body into a predetermined size, binder removal treatment, firing and annealing were performed to obtain a sintered body.

  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 to obtain a multilayer ceramic chip capacitor sample.

  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 1 μm, and the thickness of the internal electrode layer 3 is 1 μm. Met.

Evaluation of Capacitor Sample The capacitor sample obtained was evaluated for short-circuit failure characteristics, withstand voltage characteristics (IR characteristics), and the presence or absence of delamination.

  As for short-circuit failure characteristics, a tester applied 1.5 V and judged that a product of 1 MΩ or less was a failure, and a failure rate of less than 5% was considered good.

With respect to the withstand voltage characteristics (IR characteristics), a DC voltage 12 times the rated voltage (6.3 V) was applied for 3 seconds, and a capacitor sample having a resistance of less than 10 ⁴ Ω was determined to have a failure, and the average failure rate was 1. Less than 9% was considered good.

  About the presence or absence of delamination, the baking base was grind | polished and the lamination state was observed visually.

  The results are shown in Table 2.

  As shown in Table 2, capacitor samples (sample numbers 4, 5, and 6) prepared using a conductive paste containing isobornyl propionate, isobornyl butyrate, and isobornyl isobutyrate as solvents. Compared with a capacitor sample manufactured using a conductive paste containing terpineol or dihydroterpineol, it can be confirmed that it is drastically improved in terms of short circuit failure, failure rate, and delamination. The above improvement in performance is also observed when compared with a capacitor sample made using a conductive paste containing dihydroterpinyl acetate. That is, about the Example sample of this invention, the reliability improvement was confirmed compared with the comparative example sample.

Example 3
A multilayer ceramic chip in the same manner as in Example 2 except that the solvent in the organic vehicle used for producing the conductive paste was a mixed solvent of isobornyl propionate: terpineol = 90: 10 (weight ratio). Capacitor samples were prepared and evaluated in the same manner. As a result, the short failure rate was less than 5%, the average failure rate was less than 1.9%, and the occurrence of delamination was not confirmed.

Example 4
Multilayer ceramic chip in the same manner as in Example 2 except that the solvent in the organic vehicle used for producing the conductive paste was a mixed solvent of isobornyl isobutyrate: terpineol = 80: 20 (weight ratio). Capacitor samples were prepared and evaluated in the same manner. As a result, the short failure rate was less than 5%, the average failure rate was less than 1.9%, and the occurrence of delamination was not confirmed.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 2 (A) and FIG. 2 (B) are photomicrographs showing the compatibility between isobornyl propionate and the ceramic green sheet. 3 (A) to 3 (C) are photomicrographs showing the compatibility between isobornyl isobutyrate and the ceramic green sheet. 4A is a photomicrograph showing the compatibility between terpineol and the ceramic green sheet, and FIG. 4B is a photomicrograph showing the compatibility between dihydroterpineol and the ceramic green sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 10 ... Capacitor body 2 ... Dielectric layer 3 ... Internal electrode layer 4 ... External electrode

Claims (8)

A conductive paste used to form internal electrodes of a multilayer ceramic electronic component,
Including conductive powder and organic vehicle;
The organic binder in the organic vehicle is mainly composed of ethyl cellulose,
A conductive paste characterized in that a solvent in the organic vehicle is mainly composed of at least one selected from isobornyl propionate, isobornyl butyrate and isobornyl isobutyrate.   The conductive paste according to claim 1, wherein the solvent in the organic vehicle is contained in an amount of 50 to 200 parts by weight with respect to 100 parts by weight of the conductive powder.   The conductive paste according to claim 1 or 2, wherein the organic binder in the organic vehicle is contained in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of the conductive powder.   The electrically conductive paste in any one of Claims 1-3 in which the said electrically conductive powder has Ni or Ni alloy as a main component. The solvent in the organic vehicle contains one or more selected from isobornyl butyrate and isobornyl isobutyrate, and terpineol,
5. The conductive paste according to claim 1, wherein a content of the terpineol in the solvent is more than 0 wt% and 20 wt% or less with respect to 100 wt% of the whole solvent. The solvent in the organic vehicle contains isobornyl propionate and terpineol,
5. The conductive paste according to claim 1, wherein a content of the terpineol in the solvent is more than 0 wt% and 10 wt% or less with respect to 100 wt% of the whole solvent. A green ceramic laminate in which a plurality of ceramic green sheets containing butyral resin and having a thickness of 5 μm or less, and electrode layers formed in a predetermined pattern using the conductive paste according to claim 1 are alternately stacked. Manufactured using the body,
A multilayer ceramic electronic component having an internal electrode layer and a dielectric layer having a thickness of 3 μm or less. A green ceramic laminate in which a plurality of ceramic green sheets containing butyral resin and having a thickness of 5 μm or less, and electrode layers formed in a predetermined pattern using the conductive paste according to claim 1 are alternately stacked. A method of manufacturing a multilayer ceramic electronic component for firing a body.