JP2012153567A - Method for manufacturing multilayer electronic component, green sheet paint used in the method and method for manufacturing multilayer unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer electronic component manufacturing method that causes no sheet attack phenomenon in manufacturing a multilayer electronic component using a so-called multi manufacturing method and thus provides a resultant electronic component experiencing a reduced rate of a short-circuit defect, a green sheet paint used in the method and a method for manufacturing a multilayer unit using the green sheet paint.SOLUTION: A green sheet paint includes dielectric powder, a binder resin and a mixed solvent comprised of two or more kinds of solvents, wherein the solubility parameter (δ) of the mixed solvent is 9.3 to 10.3, the binder resin is a butyral-based resin, the content of the binder resin is 10 to 26 pts.wt. relative to 100 pts.wt. of the dielectric powder.

Description

  The present invention relates to a method for manufacturing a multilayer electronic component, a green sheet paint used in the method, and a method for manufacturing a multilayer unit.

  As a method for manufacturing a laminated electronic component such as a capacitor, a piezoelectric element, a PTC thermistor, an NTC thermistor, or a varistor, for example, the following method is known. That is, first, a ceramic coating containing ceramic powder, an organic binder, a plasticizer, a solvent and the like is formed into a sheet shape on a flexible support (for example, a PET film) by a doctor blade method or the like to obtain a green sheet. On the green sheet, a paste containing an electrode material such as palladium, silver, or nickel is printed in a predetermined pattern to form an electrode pattern layer.

  When obtaining a laminated structure, the obtained green sheets are laminated so as to have a desired laminated structure, and a ceramic green chip is obtained through a press cutting step. The binder in the ceramic green chip thus obtained is burned out and fired at 1000 ° C. to 1400 ° C., and terminal electrodes such as silver, silver-palladium, nickel, or copper are formed on the obtained fired body. Then, a ceramic multilayer electronic component is obtained.

  In the above-described manufacturing method, for example, when manufacturing a multilayer ceramic capacitor, it is conceivable to reduce the thickness of the dielectric layers per layer and increase the number of stacks as a technique for reducing the size and increasing the capacity. However, in the method in which the green sheet is peeled off from the flexible support and laminated, particularly in the case of a thin green sheet, the green sheet cannot be peeled off well from the flexible support, resulting in a very poor lamination yield. In addition, since a thin green sheet is handled, a defective product such as a short circuit frequently occurs in the finished product.

  As a means for solving such problems, a step of forming a green sheet on a flexible support and a step of printing an electrode pattern on the green sheet include a necessary number of layers (sheet application and printing). It is possible to obtain a laminated unit by repeating the process only, and stack these laminated units (so-called multi-method). As a result, the sheet stacking unit can be peeled from the support without damaging the sheet because the thickness of the sheet stacking unit to be peeled off from the support is increased (Patent Document 1 below).

  However, in this conventional manufacturing method, the process of printing an electrode pattern on the dried first green sheet and further laminating the second green sheet thereon is a wet-on-dry process. There is an inconvenience due to the system. That is, the first layer sheet is eroded by the solvent during printing of the second layer green sheet (sheet attack by the solvent). Therefore, the thickness of the green sheet in the laminated unit becomes non-uniform, the surface roughness of the sheet increases, and the short-circuit defect rate of the laminated electronic component obtained by laminating and firing the laminated unit increases.

  In particular, when the thickness of the sheet per layer is reduced, such inconvenience appears remarkably, making it difficult to manufacture a small-sized and large-capacity multilayer ceramic capacitor. As shown in Patent Document 2 below, the first layer green sheet is made of an organic paint, and the second layer green sheet is made of a water-soluble paint to prevent sheet attack. A method for manufacturing a laminated electronic component is known.

  However, when the second-layer green sheet is made of a water-soluble paint to prevent sheet attack, the strength of the laminated unit tends to be insufficient, and the laminated unit is damaged in the peeling process from the support. It is difficult to peel without.

  In addition, in order to compensate for the lack of strength of the laminated unit, when the third green sheet is applied to form the laminated unit, there is a problem that the total number of processes increases because the number of green sheet manufacturing processes increases. .

Japanese Patent No. 3190177 JP 2007-234829 A

  The present invention has been made in view of such a situation, and the object thereof is to prevent occurrence of a sheet attack phenomenon when manufacturing a laminated electronic component using a so-called multi-construction method, and a short defect rate of the resulting electronic component. It is providing the manufacturing method of a multilayer electronic component with few, the green sheet coating material used for the manufacturing method, and the manufacturing method of a lamination | stacking unit.

  When manufacturing multilayer electronic components using a so-called multi-construction method, the present inventors do not generate a sheet attack phenomenon, and the resulting electronic component manufacturing method has a low short-circuit defect rate, and its As a result of intensive studies on the green sheet paint used in the production method, the following invention has been completed.

That is, the green sheet paint according to the present invention is
A green sheet paint comprising a dielectric powder, a binder resin, and a mixed solvent composed of two or more solvents,
The solubility parameter (δ _mix ) of the mixed solvent is 9.3 to 10.3;
The binder resin is a butyral resin;
A content of the binder resin is 10 to 26 parts by weight with respect to 100 parts by weight of the dielectric powder.

In the green sheet paint according to the present invention, the solubility parameter (δ _mix ) of the mixed solvent contained in the green sheet paint is set to 9.3 to 10.3, and the content of the binder resin contained in the green sheet paint is determined as the dielectric powder. 10 to 26 parts by weight with respect to 100 parts by weight. It has been confirmed by experiments by the present inventors that a so-called sheet attack (erosion of the lower green sheet) can be suppressed when the laminated unit is manufactured using the green sheet paint by such a configuration. When the solubility parameter (δ _mix ) of the mixed solvent contained in the green sheet paint and the content of the binder resin are not within the predetermined ranges, the sheet attack cannot be effectively prevented.

  In the green sheet paint according to the present invention, when a laminated unit is produced, the sheet attack can be effectively prevented, so that the thickness of the green sheet is not uneven and the surface roughness of the sheet is increased. The short circuit defect rate of the multilayer electronic component obtained by laminating and firing the multilayer units is reduced.

  In the present invention, the butyral resin is used as a concept including polyvinyl butyral and polyvinyl acetal.

  Preferably, in the mixed solvent, the addition ratio of the alcohol solvent is 15 to 45% by volume, the addition ratio of the ketone solvent is 5 to 50% by volume, and the total addition of the aromatic solvent and the ester solvent The ratio is 25-50% by volume.

  Preferably, in the mixed solvent, the solubility parameter (δ) of the alcohol solvent is 11 to 13, the solubility parameter (δ) of the ketone solvent is 9 to 10, the aromatic solvent and the ester solvent The solubility parameter (δ) is 8-9.

  In the present invention, by defining the mixed solvent as described above, it is possible to obtain a green sheet paint that is less susceptible to sheet attack when a laminated unit is produced.

  Preferably, in the mixed solvent, the difference in the addition ratio of the alcohol solvent and the ketone solvent is in the range of 10% by volume. In the mixed solvent, by defining the difference in the addition ratio of the alcohol solvent and the ketone solvent in such a range, it becomes possible to prevent sheet attack particularly effectively and to effectively prevent short circuit failure. it can.

The manufacturing method of the laminated unit according to the present invention is as follows:
Forming a first green sheet comprising a first green sheet paint;
Printing a conductive paste on the first green sheet to form a first electrode pattern;
Forming a second green sheet made of a second green sheet paint on the surface of the first green sheet on which the first electrode pattern is formed;
A step of printing the conductive paste on the second green sheet to form a second electrode pattern;
The first green sheet paint and the second green sheet paint are the green sheet paints described above.

  In the laminated unit according to the present invention, since the sheet attack can be effectively prevented, the thickness of the green sheet does not become non-uniform and the surface roughness of the sheet does not increase, and the laminated unit is laminated and fired. As a result, the short-circuit defect rate of the laminated electronic component obtained is reduced.

  Preferably, the first green sheet paint and the second green sheet paint are the same green sheet paint. In the present invention, even if the first green sheet and the second green sheet are formed of the same green sheet paint, sheet attack can be effectively prevented. However, the first green sheet paint and the second green sheet paint are not necessarily the same, and may be different green sheet paints.

  Preferably, the film thicknesses of the first green sheet and the second green sheet are each 5 μm or less, more preferably 2 μm or less.

  When the first green sheet and the second green sheet are thick, the influence of the sheet attack is small and the short-circuit defect rate is also small. However, as the film thickness of the first green sheet and the second green sheet becomes thinner, the influence of the sheet attack becomes larger. However, according to the present invention, even when the film thicknesses of the first green sheet and the second green sheet are as thin as 5 μm or less, 2 μm or less, 1 μm or less, and 0.2 μm or less, the occurrence of sheet attack is suppressed. Can do.

Preferably, Ras is a first surface roughness of a portion where the first green sheet is exposed before the second green sheet is formed, and the second green after the second green sheet is formed. When the second surface roughness of the portion where the sheet is exposed is Ram,
The surface roughness change rate ΔRa expressed as a percentage by dividing the absolute value ΔRa of the difference between the second surface roughness Ram and the first surface roughness Ra by the second surface roughness Ram is preferably 25% or less, preferably Is 14% or less, more preferably 8% or less.
In the method for manufacturing a laminated unit according to the present invention, the first green sheet paint and the second green sheet paint are the green sheet paints described above, so that the surface roughness change rate ΔRa is reduced as described above. It becomes possible to do. As a result, the short circuit defect rate of the multilayer electronic component obtained by laminating and firing the multilayer units is reduced.

A method for manufacturing a laminated electronic component according to the present invention includes:
Stacking the above-described multilayer units to obtain a ceramic laminate;
Cutting the ceramic laminate to obtain a ceramic green chip;
Firing the ceramic green chip.

FIG. 1 is a schematic cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. 2 (A) to 2 (D) are cross-sectional views showing the main part of the manufacturing process of the method for manufacturing the multilayer ceramic capacitor shown in FIG. FIG. 3 is a fragmentary cross-sectional view showing a step continued from FIG.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

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

  As shown in FIG. 1, the multilayer ceramic capacitor 2 according to this embodiment includes a capacitor body 4, a first terminal electrode 6, and a second terminal electrode 8. The capacitor body 4 includes dielectric layers 10 and internal electrode layers 12, and the internal electrode layers 12 are alternately stacked between the dielectric layers 10. One of the internal electrode layers 12 stacked alternately is electrically connected to the inside of the first terminal electrode 6 formed outside the first end of the capacitor element body 4. The other internal electrode layers 12 that are alternately stacked are electrically connected to the inside of the second terminal electrode 8 that is formed outside the second end of the capacitor body 4.

  The material of the dielectric layer 10 is not particularly limited, and is made of a dielectric powder such as calcium titanate, strontium titanate and / or barium titanate. The thickness of each dielectric layer 10 is not particularly limited, but is generally several μm to several hundred μm. In particular, in this embodiment, the thickness is preferably 5 μm or less, more preferably 2 μm or less, and particularly preferably 1 μm or less.

Although the material of the terminal electrodes 6 and 8 is not particularly limited, copper, a copper alloy, nickel, a nickel alloy, or the like is usually used, 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.
The shape and size of the multilayer ceramic capacitor 2 may be appropriately determined according to the purpose and application. When the multilayer ceramic capacitor 2 has a rectangular parallelepiped shape, it is usually vertical (0.6 to 5.6 mm, preferably 0.6 to 3.2 mm) × horizontal (0.3 to 5.0 mm, preferably 0.3 to 1.6 mm) × thickness (0.1 to 1.9 mm, preferably 0.3 to 1.6 mm).

  Next, an example of a method for manufacturing the multilayer ceramic capacitor 2 according to the present embodiment will be described. First, the composition of the paint used for production will be described.

First Green Sheet Paint In the present embodiment, the first green sheet is formed from the first green sheet paint. The first green sheet paint is obtained by kneading a dielectric powder and an organic vehicle. The organic vehicle is obtained by dissolving a binder resin in an organic solvent.
The dielectric 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 dielectric powder is usually used as a powder having an average particle size of 0.3 μm or less, preferably 0.2 μm or less. In order to form a very thin green sheet, it is desirable to use a powder finer than the thickness of the green sheet.

  In the present embodiment, a first butyral resin such as polyvinyl butyral is used as the binder resin used in the organic vehicle for the first green sheet paint. Moreover, it is preferable that a plasticizer is content of 10-50 weight part with respect to 100 weight part of binder resin. If the amount of the plasticizer is too small, the green sheet tends to become brittle. If the amount is too large, the plasticizer oozes out and it becomes difficult to handle the green sheet. Examples of the plasticizer include phthalic acid esters such as dioctyl phthalate (DOP) and benzylbutyl phthalate, adipic acid, phosphoric acid ester, and glycols.

In this embodiment, the organic solvent used in the organic vehicle for the first green sheet paint is composed of two or more kinds of solvents, and the solubility parameter SP value (δ _mix ) of the mixed solvent is preferably 9.3 to 10.3. Is a mixed solvent of 9.4 to 10.1.

In the present invention, the SP value (δ _mix ) of the mixed solvent is a value defined by regular solution theory and is a measure of the solubility of the two-component solution. The SP value (δ _mix ) is expressed by the following equation (1).
δ _mix = (φ ₁ V ₁ δ ₁ + φ ₂ V ₂ δ ₂ ) / (V ₁ δ ₁ + V ₂ δ ₂ ) (1)

In the above formula,
δ ₁ , δ ₂ : solubility parameter SP value of solutions 1 and 2;
φ ₁ , φ ₂ : volume fraction of solutions 1 and 2,
V ₁ , V ₂ : molar volumes of liquids 1 and 2.
Further, the solubility parameter SP value (δ) of the solutions 1 and 2 is obtained by the following equation (2).
δ = (ΔE / V) ^1/2 (2)

In the above formula,
ΔE: Evaporation energy,
V: molar volume.

  As such a mixed solvent, a solvent that is a good solvent for the butyral resin is preferably contained as a main component. Solvents that are good solvents for butyral resins include alcohols such as ethanol, npropanol, isopropanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, and 2-methyl-2-propanol. It is a solvent containing as a main component at least one or more of solvents, and at least one or more of ketone solvents represented by acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, diethyl ketone and the like.

  Moreover, as a mixed solvent, it is preferable that the solvent used as a poor solvent with respect to a butyral resin is also contained. Solvents that are poor solvents for butyral resins include at least one of aromatic solvents such as toluene, xylene, and ethylbenzene, and ethers such as ethyl acetate, propyl acetate, isopropyl acetate, and butyl acetate. It is a solvent containing at least one type of solvent.

In this embodiment, by combining the organic solvents according to the above mathematical formulas (1) and (2), the solubility parameter SP value (δ _mix ) of the mixed solvent is 9.3 to 10.3, preferably 9 A mixed solvent of 4 to 10.1 is obtained. If the SP value of this mixed solvent is too small, the solubility of the binder resin tends to decrease, and the viscosity of the green sheet paint tends to increase. If it is too large, the sheet attack tends to become significant.

  Furthermore, preferably in the mixed solvent, the addition ratio of the alcohol solvent is 15 to 45% by volume, more preferably 20 to 40% by volume, and the addition ratio of the ketone solvent is 5 to 50% by volume, More preferably, it is 15-45 volume%, and the sum total addition ratio of an aromatic solvent and ester solvent is 25-50 volume%, More preferably, it is 30-50 volume%.

  Preferably, in the mixed solvent, the SP value (δ) of the alcohol solvent is 11 to 13, more preferably 11.2 to 12.7, and the SP value (δ) of the ketone solvent is 9 10 and more preferably 9.2 to 9.9, and the SP value (δ) of the aromatic solvent and the ester solvent is 8 to 9, more preferably 8.2 to 8.9. is there.

  Preferably, in the mixed solvent, the difference in the addition ratio of the alcohol solvent and the ketone solvent is within a range of 10% by volume, more preferably the addition ratio of the alcohol solvent and the ketone solvent is substantially the same. It is.

  The butyral group amount of the butyral resin in the first green sheet paint is 63 to 78 mol%, preferably 65 to 75 mol%, and the residual acetyl group is 5 mol% or less, preferably 0 to 3 mol%. The degree of polymerization of the first butyral resin is 800 to 2300, preferably 1000 to 2000.

  The first butyral resin in the first green sheet paint is included in an amount of 10 to 26 parts by weight, preferably 12 to 24 parts by weight, based on 100 parts by weight of the dielectric powder. If the amount of this resin is too small, the sheet attack at the time of producing the second green sheet tends to be significant, and if it is too large, when the laminate unit is peeled off from the carrier sheet and laminated, a portion that cannot be peeled is generated. A part of the laminated unit tends to be defective.

  The organic solvent is preferably 200 to 500 parts by weight with respect to 100 parts by weight of the dielectric powder. The first green sheet paint may contain an additive selected from various dispersants, plasticizers, dielectrics, glass frit, insulators, antistatic agents, and the like as necessary. However, the total content of these additives is desirably 10 parts by weight or less with respect to 100 parts by weight of the paint.

1st electrode coating material In this embodiment, a 1st electrode pattern layer is formed from a 1st electrode coating material. In the present embodiment, an organic solvent-based paint that is incompatible with the first green sheet paint is preferably used as the first electrode paint. The first electrode paint is prepared by kneading a conductive material made of various conductive metals or alloys, or various oxides, organometallic compounds, resinates, or the like, which become the conductive material described above after firing, and an organic vehicle. .

  As the conductor material used when the first electrode paint is manufactured, Ni, Ni alloy, or a mixture thereof is used. There are no particular restrictions on the shape of such a conductor material, such as a spherical shape or a flake shape, and 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.

  In the present embodiment, examples of the binder resin contained in the first electrode paint include ethyl cellulose and polyvinyl butyral. Preferably, ethyl cellulose is used. The binder resin for the first electrode paint is preferably included in the electrode paste in an amount of 4 to 10 parts by weight with respect to 100 parts by weight of the conductor material (metal powder).

  In the present embodiment, an organic solvent that is incompatible with the first green sheet paint is preferably used as the organic solvent for the first electrode paint. Examples of the solvent for the first electrode coating material include terpineol and dihydroterpineol. Preferably, dihydroterpineol is used. The solvent content for the first electrode paint is preferably about 20 to 55% by weight relative to the entire first electrode paint.

  The first electrode paint preferably contains a plasticizer or an adhesive. As a result, the adhesiveness and tackiness between each electrode pattern layer and the green sheet are improved. The same plasticizer as the first green sheet paint can be used as the plasticizer, and the amount of the plasticizer added is preferably 10 to 300 parts by weight, more preferably 100 parts by weight of the binder in the first electrode paint. 10 to 200 parts by weight. In addition, when there is too much addition amount of a plasticizer or an adhesive, there exists a tendency for the intensity | strength of a 1st electrode pattern layer to fall remarkably.

Second Green Sheet Paint In the present embodiment, the second green sheet is formed from the second green sheet paint. The second green sheet paint is obtained by kneading a dielectric powder and an organic vehicle. The organic vehicle is obtained by dissolving a binder resin in an organic solvent.

  As the dielectric powder, the same powder as the first green sheet paint is used.

In the present embodiment, the organic solvent used in the organic vehicle for the second green sheet paint is composed of two or more of the above-mentioned solvents, and the solubility parameter SP value (δ _mix ) of the mixed solvent is 9.3 to 10.3, More preferably, a mixed solvent of 9.4 to 10.1 is used. As various solvents constituting such a mixed solvent, those similar to the first green sheet paint are used.

  As the butyral resin used for the second green sheet paint, the same resin as the first green sheet paint is used, and the blending ratio thereof is also the same.

  Other components and blending ratios contained in the second green sheet paint are the same as those in the first green sheet paint.

Second electrode paint In the present embodiment, the second electrode pattern layer is formed from the second electrode paint. In the present embodiment, an organic solvent-based paint that is incompatible with the second green sheet paint is preferably used as the second electrode paint. More preferably, an organic solvent-based paint that is incompatible with the second green sheet paint and the first green sheet paint is used as the second electrode paint. As the second electrode paint, for example, the same one as the first electrode paint may be used.

First Layer Laminating Step Next, each manufacturing step will be described. First, as shown in FIG. 2A, a first green sheet paint is applied on a carrier sheet 20 (support) to form a first green sheet 10a.

  If necessary, the formed first green sheet 10a is dried. The drying temperature of the first 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 2 μm or less, and particularly preferably 1 μm or less.

  Although it does not specifically limit as a formation method of the 1st green sheet 10a, For example, a doctor blade method etc. are mentioned.

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

  Next, as shown in FIG. 2 (B), the first electrode paint is printed in a predetermined pattern on the surface of the first green sheet 10a formed on the carrier sheet 20 to form the first electrode pattern layer 12a. . In addition, before and after that, a first green sheet paint is printed on the surface of the first green sheet 10a on which the first electrode pattern layer 12a is not formed, and a first blank having substantially the same thickness as the first electrode pattern layer 12a. A pattern layer may be formed. In the illustrated embodiment, the first blank pattern layer is not formed.

  Even if the second green sheet 10b is formed on the first electrode pattern layer 12a by forming the first blank pattern layer, no step or the like is formed on the second green sheet 10b. The chip shape is also good.

  Examples of the method for forming the first electrode pattern layer 12a include a thick film forming method such as the above-described printing method (screen printing method or gravure printing method), or a thin film method such as vapor deposition or sputtering. In the present embodiment, a printing method is preferably used.

  The 1st electrode pattern layer 12a is dried as needed. The drying temperature is not particularly limited, but is preferably 70 to 120 ° C., and the drying time is preferably 5 to 15 minutes. The thickness of the first electrode pattern layer 12a after drying is not particularly limited, but is about 30 to 80% of the thickness of the first green sheet 10a after drying.

Step of Laminating Second Layer Next, as shown in FIG. 2C, a second green sheet paint is applied on the first electrode pattern layer 12a to form a second green sheet 10b. The second green sheet 10b is formed by the same method as the first green sheet 10a.

  If necessary, the formed second green sheet 10b is dried. The thickness of the second green sheet 10b after drying shrinks to a thickness of 5 to 25% as compared with that before drying. The thickness of the second green sheet 10b after drying is preferably 5 μm or less, more preferably 2 μm or less, and particularly preferably 1 μm or less.

  Next, as shown in FIG. 2D, a second electrode paint layer is printed on the surface of the second green sheet 10b in a predetermined pattern to form a second electrode pattern layer 12b. In addition, before and after that, a second green sheet paint is printed on the surface of the second green sheet 10b on which the second electrode pattern layer 12b is not formed, and a second blank having substantially the same thickness as the second electrode pattern layer 12b. A pattern layer may be formed. In the illustrated embodiment, the second blank pattern layer is not formed. The second electrode pattern layer 12b is formed and dried by the same method as the first electrode pattern layer 12a.

  In the present embodiment, the stacked unit U1 is obtained without forming another third green sheet on the surface of the second green sheet 10b on which the second electrode pattern layer 12b is formed.

  In the present embodiment, the first green sheet 10a and the first electrode pattern layer 12a of the first layer, and the second green sheet 10b and the second electrode pattern layer 12b of the second layer form a single stacked unit U1. Constitute. A large number of stacked units U1 are stacked in the next step.

Lamination Press Process of Laminating Unit U1 Next, in the laminating press process, as shown in FIG. 3, another laminating unit in which the laminating unit U1 peeled off from the carrier sheet 20 is laminated on the carrier sheet 20 is provided. A large number of layers are stacked on U1. The carrier sheet 20 shown in FIG. 2 and the carrier sheet 20 shown in FIG. 3 may be the same or different. By repeating the stacking of the stacking unit U1, a stacked body in which a large number of green sheets and electrode pattern layers are stacked in the stacking direction Z is obtained.

  In the present embodiment, a large number of stacking units U1 are stacked in the stacking direction Z, the stacked body is heated and pressurized, and then cut into a predetermined size to form a green chip. Although not shown, an exterior green sheet on which no electrode pattern layer is formed is laminated at the lamination end in the lamination direction Z of the lamination unit U1. The heating temperature is preferably 40 to 100 ° C. The pressure during pressurization is preferably 10 to 200 MPa.

  In the present embodiment, the first electrode pattern layer 12a and the second electrode pattern layer 12b (FIG. 2) in the green chip become the internal electrode layer 12 (FIG. 1) after firing, and the first green sheet 10a and the second green sheet 10b. (FIG. 2) becomes the dielectric layer 10 (FIG. 1) after firing.

Debinding the green chip, baking treatment, and heat treatment Next, the green chip was subject to binder removal treatment, firing treatment, and heat treatment for re-oxidizing the dielectric layer is performed.

The binder removal treatment may be performed under normal conditions. However, when a base metal such as Ni or a Ni alloy is used as the conductive material of the electrode pattern layer, it is particularly preferable to perform under the following conditions.
Temperature increase rate: 5 to 300 ° C./hour,
Holding temperature: 200-400 ° C.
Retention time: 0.5-20 hours,
Atmospheric gas: A mixed gas of humidified N ₂ and H ₂ .

The firing conditions are preferably the following conditions.
Temperature increase rate: 50 to 500 ° C./hour,
Holding temperature: 1100-1300 ° C.
Retention time: 0.5-8 hours,
Cooling rate: 50 to 500 ° C./hour,
Atmospheric gas: A mixed gas of humidified N ₂ and H ₂ or the like.

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

The heat treatment after such firing is preferably carried out at a holding temperature or maximum temperature of preferably 1000 ° C. or higher, more preferably 1000 to 1100 ° C. 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.

The other heat treatment conditions are preferably the following conditions.
Retention time: 0-6 hours,
Cooling rate: 50 to 500 ° C./hour,
Atmospheric gas: humidified N ₂ gas or the like.

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, after raising the temperature under N ₂ gas atmosphere with N ₂ gas or wet to the holding temperature of the binder removal processing, further continuing the heating to change the atmosphere Preferably, after cooling to the holding temperature at the time of heat treatment, it is preferable to change to N ₂ gas or a humidified N ₂ gas atmosphere and continue cooling. In the heat treatment, the temperature may be changed to a holding temperature in an N ₂ gas atmosphere, and the atmosphere may be changed, or the entire process of the heat treatment may be a humidified N ₂ gas atmosphere.

The sintered body thus obtained (capacitor body 4 in FIG. 1) is subjected to end face polishing, for example, by barrel polishing, sandblasting, etc., and terminal electrode paste 6 is baked to form terminal electrodes 6 and 8. To do. 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. The terminal electrode paste may be prepared in the same manner as the first electrode paint or the second electrode paint (electrode pattern layer paste).

  The multilayer ceramic capacitor 2 of the present invention thus manufactured is mounted on a printed circuit board by soldering or the like and used for various electronic devices.

  In the first green sheet paint and the second green sheet paint of the present embodiment, the SP value of the mixed solvent is 9.3 to 10.3, and the binder resin content is 100 parts by weight of the dielectric powder. 10 to 26 weight. With such a configuration, even if the first green sheet and the second green sheet are formed with the same paint, the so-called sheet attack (erosion of the lower green sheet) can be effectively suppressed.

  In the laminated unit U1 according to the present embodiment, since the sheet attack can be effectively prevented, the thickness of the green sheets 10a and 10b does not become uneven and the surface roughness of the sheets 10a and 10b does not increase. . For example, as shown in FIG. 2B, the portion where the first green sheet 10a is exposed before the second green sheet 10b is formed and after the first electrode pattern layer 12a is formed. The first surface roughness is Ras. Further, as shown in FIG. 2D, when the second surface roughness of the portion where the surface of the second green sheet 10b after the second electrode pattern layer 12b is formed is Ram, The following relationship holds.

  That is, the surface roughness change rate ΔRa expressed as a percentage by dividing the absolute value ΔRa of the difference between the second surface roughness Ram and the first surface roughness Ra by the second surface roughness Ram is 25% or less, preferably It is 14% or less, more preferably 8% or less. This indicates that the seat attack is suppressed. Conversely, when the surface roughness change rate ΔRa is large, it is considered that a large amount of sheet attack occurs.

  In the present embodiment, it is possible to reduce the short-circuit defect rate of the multilayer ceramic capacitor 2 shown in FIG. 1 obtained by laminating and firing the multilayer unit U1 in which the sheet attack is suppressed.

  Moreover, since the laminated unit U1 is thicker than the green sheet alone, it has a high strength. Therefore, it is possible to easily peel the laminated unit from the carrier sheet 20 without damaging the unit U1. Moreover, the laminated unit U1 of the present embodiment is configured by a two-layer green sheet structure of the first green sheet 10a and the second green sheet 10b without forming another third green sheet. . Therefore, compared with the case where three or more green sheets are laminated to form a laminated unit, there is an advantage that the process can be shortened by omitting the green sheet manufacturing process. In addition, when calling a two-layer green sheet structure, an electrode pattern layer and a blank pattern layer are not counted in the total number.

  The present invention is not limited to the above-described embodiments, and can be variously modified within the scope of the present invention. For example, in the above-described embodiment, the first green sheet paint and the second green sheet paint are the same green sheet paint. However, if the green sheet paint is within the scope of the present invention, the first green sheet paint is used. Even when the paint and the second green sheet paint are different, sheet attack can be similarly prevented. However, by making the first green sheet paint and the second green sheet paint the same green sheet paint, the manufacturing process can be simplified and sheet attack can be prevented particularly effectively, and short circuit defects can be prevented. It can be effectively prevented.

  The method of the present invention is not limited to a method for manufacturing a multilayer ceramic capacitor, but can also be applied as a method for manufacturing other multilayer ceramic electronic components.

  Hereinafter, the present invention will be described based on further detailed examples, but the present invention is not limited to these examples.

Sample 1
First, a first green sheet paint was prepared. The first green sheet paint was produced as follows. That is, BaTiO ₃ , MgCO ₃ , MnCO ₃ , (Ba, Ca) SiO ₃ and rare earth compounds having an average particle diameter of 150 nm, polyvinyl butyral resin, alcohol solvents, aromatic solvents, ester solvents and ketone solvents A mixed solvent was prepared as above, and a dispersant, a plasticizer, and the like were added and mixed as necessary to form a slurry to prepare a first green sheet paint.

As the mixed solvent, those having an SP value (δ _mix ) of 9.6 were used. Such a mixed solvent was prepared by adjusting the addition ratio of various solvents. The solvent used for the mixed solvent is n-propanol, which is an alcohol solvent, 30% by volume, toluene, which is an aromatic solvent, 20% by volume, and butyl acetate, which is an ester solvent, 20% by volume. The addition ratio of methyl ethyl ketone (MEK), which is a ketone solvent, was 30% by volume.

  Further, as the polyvinyl butyral resin, a polyvinyl butyral resin having a polymerization degree of 1200, a butyral group amount of 70 mol% and a residual acetyl group of 5 mol% or less is used, and the addition amount thereof is 100 parts by weight of dielectric powder. And 16 parts by weight.

  The second green sheet paint was the same green sheet paint as the first green sheet paint.

  Moreover, the 1st electrode coating material and the 2nd electrode coating material were prepared. The first electrode paint and the second electrode paint are the same electrode paste, and are Ni pastes composed of solvent species that are incompatible with the first green sheet paint. Specifically, the Ni paste is a paste containing Ni powder having an average particle size of 0.2 μm, dihydroterpineol, ethyl cellulose resin, and DOP.

  Next, as shown in FIG. 2A, first, a first green sheet paint is applied to a thickness of 20 μm on a PET film (carrier sheet 20) by a doctor blade method, and the first green sheet 10a is applied. Formed. Next, the 1st green sheet 10a formed on the PET film was continuously sent in the drying furnace, and the solvent contained in the 1st green sheet 10a was dried. The drying temperature was 75 ° C. and the drying time was 2 minutes. The thickness of the first green sheet after drying was 2 μm.

  Next, the 1st electrode coating material was apply | coated to the surface of the 1st green sheet 10a formed on PET film by the screen printing method, and the 1st electrode pattern layer 12a was formed. Next, the first electrode pattern layer 12a formed on the first green sheet 10a was continuously fed into a drying furnace and dried at 90 ° C. for 10 minutes.

  Next, the second green sheet paint is applied to the surface of the first green sheet 10a on which the first electrode pattern layer 12a is formed to a thickness of 20 μm by the doctor blade method using the second green sheet paint described above. Then, the second green sheet 10b was formed. Next, the carrier sheet 20 on which the second green sheet 10b was formed was continuously fed into a drying furnace to dry the solvent. The drying temperature was 75 ° C. and the drying time was 2 minutes. The thickness of the second green sheet after drying was 2 μm.

  Next, the 2nd electrode coating material was apply | coated to the surface of the 2nd green sheet 10b with the screen printing method, and the 2nd electrode pattern layer 12b was formed. The second electrode pattern layer 12b formed on the second green sheet 10b was continuously fed into a drying furnace and dried at 90 ° C. for 10 minutes. After drying, a laminated unit U1 was obtained. A plurality of the laminated units U1 were produced.

  Next, after peeling the carrier sheet 20 from each lamination unit U1, as shown in FIG. 3, lamination units U1 were laminated | stacked one after another and thermocompression bonded, and the laminated body was obtained.

  Next, this laminate was cut into a predetermined size to obtain a ceramic green chip. Next, the ceramic green chip was heated to remove the binder. Next, the ceramic green chip was fired at 1000 ° C. to 1400 ° C. to obtain a sintered body. Next, in order to re-oxidize the dielectric layer in the sintered body, the sintered body was heated. A terminal electrode was formed on the reoxidized fired body to obtain a multilayer ceramic capacitor.

  The size of the multilayer ceramic capacitor was 1.6 mm in the L dimension and 0.8 mm in the W dimension. The number of stacked layers (number of electrode pattern layers) was 100 layers.

  In this way, a multilayer ceramic capacitor of Sample 1 was produced. Table 1 shows combinations of solvent types used for the mixed solvent of the first green sheet paint and the second green sheet paint used in the preparation of Sample 1.

Sample 2-10
In the first green sheet paint and the second green sheet paint, except that the addition ratio of the solvent, the SP value (δ _mix ) of the mixed solvent and the resin amount were changed as shown in Table 1, Multilayer ceramic capacitors of Samples 2 to 10 were produced.

(Evaluation)
Surface roughness measurement
In the manufacturing process of the laminated unit U1 obtained in the samples 1 to 10, the surface roughness Ras of the first green sheet 10a in the state shown in FIG. 2B and the second in the state shown in FIG. Green sheet surface roughness: Ram was measured. The surface roughness was measured using a surf coder (ET3000i manufactured by Kosaka Laboratory Ltd.). From the obtained surface roughness value, the surface roughness change rate: ΔRa was calculated from the formula [ΔRa = (Ram−Ras) × 100 / Ras]. The results are shown in Table 1. ΔRa is preferably 25% or less, more preferably 14% or less, and particularly preferably 8% or less.

Short defect characteristics were evaluated as a measurement of short defect ratio and evaluation of characteristics. The short-circuit defect rate was measured for 100 samples of multilayer ceramic capacitors. In the measurement, an insulation resistance meter (E2377A manufactured by HEWLETT PACKARD) was used. In the measurement, the resistance value of each sample was measured, and a sample having a resistance value of 100 kΩ or less was determined as a short-circuit defective sample. The ratio of the sample that caused the short defect to the total measurement sample was defined as the short defect rate. The results are shown in Table 1. The short-circuit defect rate is preferably 25% or less, more preferably 12% or less, and particularly preferably 8% or less.

As shown in Table 1, in the first green sheet paint and the second green sheet paint, Samples 1, 3, 5, 7, 9 in which the SP value (δ _mix ) of the mixed solvent and the resin addition amount are within a predetermined range. And 10, the rate of change in surface roughness is ΔRa 2 to 16%, and the degree of sheet attack is expected to be light. Therefore, the short defect rate also shows a good result.

On the other hand, in the first green sheet paint and the second green sheet paint, in the sample 4 in which the SP value (δ _mix ) of the mixed solvent is smaller than the predetermined range, the change rate of the surface roughness change rate ΔRa is small, and the sheet attack Although the influence is small, since the dispersion of the first green sheet paint is insufficient, the surface roughness of the first green sheet is deteriorated as compared with other samples. As a result, the short defect rate also shows a high value.

Further, in the first green sheet paint and the second green sheet paint, in the sample 6 in which the SP value (δ _mix ) of the mixed solvent is larger than the predetermined range, the surface roughness change rate ΔRa is high, and a severe sheet attack occurs. It is predicted that As a result, all of the measurement samples were short-circuited.

  Moreover, in the first green sheet paint and the second green sheet paint, the sample 2 in which the resin addition amount is smaller than the predetermined range has a high surface roughness change rate ΔRa, and it is predicted that a severe sheet attack occurs. The As a result, the short defect rate also shows a high value.

  Further, in the first green sheet paint and the second green sheet paint, in the sample 8 in which the resin addition amount is larger than the predetermined range, the change rate ΔRa of the surface roughness is small and the influence of the sheet attack is small. When the unit was peeled from the PET film, the peeling adsorption plate and the laminated unit adhered to each other, so that the lamination could not be continued, and the production of the laminated ceramic capacitor was stopped.

Samples 20-22
The first green sheet paint and the second green sheet paint are different green sheet paints, and in the first green sheet paint and the second green sheet paint, the solvent addition ratio, the SP value (δ _mix ) and the resin amount of the mixed solvent are set. Except for the changes shown in Table 2, samples 20 to 22 of the multilayer ceramic capacitor were produced in the same manner as Sample 1, and the same evaluation was performed. The results are shown in Table 2.

As shown in Table 2, even if the first green sheet paint and the second green sheet paint are different green sheet paints, the SP value (δ _mix) of the mixed solvent is used in the first green sheet paint and the second green sheet paint. ) And the samples 20 to 22 in which the resin addition amount is within a predetermined range, it was confirmed that the change rate of the surface roughness was small in the change rate ΔRa of the surface roughness and the short-circuit defect rate was low.

  Furthermore, sample 1 in which the first green sheet paint and the second green sheet paint are the same green sheet paint is compared with samples 20 to 23 in which the first green sheet paint and the second green sheet paint are different green sheet paints. Thus, it has been confirmed that sheet attack can be particularly effectively prevented and short-circuit defects can be effectively prevented.

Samples 30-36
In the first green sheet paint and the second green sheet, the multilayer ceramic capacitor was manufactured in the same manner as in Sample 1 except that the addition ratio of various solvents and the SP value (δ _mix ) of the mixed solvent were changed as shown in Table 3. Samples 30 to 36 were prepared and subjected to the same evaluation. The results are shown in Table 3.

As shown in Table 3, the SP value (δ _mix ) of the mixed solvent is within a predetermined range even when the addition ratio of various solvents is changed in the first green sheet paint and the second green sheet paint. In Samples 30 to 36, it was confirmed that the change rate of the surface roughness was small, the change rate ΔRa of the surface roughness was small, and the short defect rate was low.

Samples 40-43
In the first green sheet paint and the second green sheet paint, the same as sample 1 except that the addition ratio of alcohol solvent and ketone solvent and the SP value (δ _mix ) of the mixed solvent were changed as shown in Table 4. Then, samples 40 to 42 of the multilayer ceramic capacitor were produced, and the same evaluation was performed. In addition, in the first green sheet paint and the second green sheet paint, the addition ratio of the alcohol solvent, the ketone solvent, and the ester solvent and the SP value (δ _mix ) of the mixed solvent were changed as shown in Table 4. Produced a sample 43 of the multilayer ceramic capacitor in the same manner as Sample 1, and performed the same evaluation. The results are shown in Table 4.

As shown in Table 4, the SP value (δ _mix ) of the mixed solvent is predetermined even when the addition ratio of the alcohol solvent and the ketone solvent is changed in the first green sheet paint and the second green sheet paint. In the samples 40 to 43 within the range, it was confirmed that the change rate of the surface roughness was small, the change rate ΔRa of the surface roughness was small, and the short-circuit defect rate was low.

  Furthermore, in the first green sheet paint and the second green sheet paint, in the samples 1, 41 and 42 in which the difference in the addition ratio of the alcohol solvent and the ketone solvent is within a desired range, sheet attack is particularly effectively prevented. It was confirmed that short circuit defects can be effectively prevented.

Sample 50-52
Except for changing the thicknesses of the first green sheet and the second green sheet, samples 50 to 52 of the multilayer ceramic capacitor were produced in the same manner as the sample 1, and the same evaluation was performed. The results are shown in Table 5.

表５に示すように、第１グリーンシートおよび第２グリーンシートの厚さが所望の範囲内にある試料５０〜５２では、表面粗さの変化率ΔＲａが小さく、ショート不良率が低いことが確認された。

As shown in Table 5, in samples 50 to 52 in which the thicknesses of the first green sheet and the second green sheet are within a desired range, it is confirmed that the surface roughness change rate ΔRa is small and the short-circuit defect rate is low. It was done.

Samples 60-65
In the first green sheet paint and the second green sheet paint, samples 60 to 65 of the multilayer ceramic capacitor are produced in the same manner as in the sample 1 except that the solvent types constituting the mixed solvent are changed as shown in Table 6. The same evaluation was performed. The results are shown in Table 6.

As shown in Table 6, in the first green sheet paint and the second green sheet paint, the SP value (δ _mix ) of the mixed solvent is within a predetermined range even when the solvent type constituting the mixed solvent is changed. In samples 60 to 65, it was confirmed that the change rate of the surface roughness was small, the change rate ΔRa of the surface roughness was small, and the short defect rate was low.

Sample 70
Sample 70 was the same as Sample 1 except that polyvinyl acetal resin having a methyl group in the acetal group was used as the butyral resin in the first green sheet paint and the second green sheet paint. Sample 70 was prepared and evaluated in the same manner. The results are shown in Table 7.

  As shown in Table 7, in the first green sheet paint and the second green sheet paint, in the sample 70 in which the binder resin is a polyvinyl acetal resin, the surface roughness change rate is small and the surface roughness change rate ΔRa is small. It was confirmed that the short-circuit defect rate was low.

  Furthermore, in the first green sheet paint and the second green sheet paint, it is confirmed that the sample 1 in which the binder resin is polyvinyl butyral resin can effectively prevent sheet attack and can effectively prevent short circuit failure. It was done.

2 ... multilayer ceramic capacitor 4 ... capacitor body 6, 8 ... terminal electrode 10 ... dielectric layer 10a ... first green sheet 10b ... second green sheet 12 ... internal electrode layer 12a ... first electrode pattern layer 12b ... second electrode Pattern layer 20 ... Carrier sheet (support)
U1, U2 ... Stacked unit

Claims (9)

A green sheet paint comprising a dielectric powder, a binder resin, and a mixed solvent composed of two or more solvents,
The solubility parameter (δ _mix ) of the mixed solvent is 9.3 to 10.3;
The binder resin is a butyral resin;
The green sheet paint, wherein the content of the binder resin is 10 to 26 parts by weight with respect to 100 parts by weight of the dielectric powder.   In the mixed solvent, the addition ratio of the alcohol solvent is 15 to 45% by volume, the addition ratio of the ketone solvent is 5 to 50% by volume, and the total addition ratio of the aromatic solvent and the ester solvent is 25. The green sheet paint according to claim 1, which is ˜50% by volume.   In the mixed solvent, the solubility parameter (δ) of the alcohol solvent is 11 to 13, the solubility parameter (δ) of the ketone solvent is 9 to 10, and the solubility parameter (δ) of the aromatic solvent and the ester solvent is (δ). ) Is 8-9, The green sheet paint according to claim 1 or 2.   The green sheet paint according to any one of claims 1 to 3, wherein in the mixed solvent, a difference in addition ratio of the alcohol solvent and the ketone solvent is within a range of 10% by volume. Forming a first green sheet comprising a first green sheet paint;
Printing a conductive paste on the first green sheet to form a first electrode pattern;
Forming a second green sheet made of a second green sheet paint on the surface of the first green sheet on which the first electrode pattern is formed;
A step of printing the conductive paste on the second green sheet to form a second electrode pattern;
The said 1st green sheet coating material and the said 2nd green sheet coating material are the green sheet coating materials in any one of Claims 1-4, The manufacturing method of the lamination | stacking unit characterized by the above-mentioned.   6. The method for manufacturing a laminated unit according to claim 5, wherein the first green sheet paint and the second green sheet paint are the same green sheet paint.   7. The method for manufacturing a laminated unit according to claim 5, wherein the first green sheet and the second green sheet each have a thickness of 5 μm or less. Ras is the first surface roughness of the exposed portion of the first green sheet before the second green sheet is formed, and the second green sheet is exposed after the second green sheet is formed. If the second surface roughness of the part that is doing is Ram,
The surface roughness change rate ΔRa expressed as a percentage by dividing the absolute value ΔRa of the difference between the second surface roughness Ram and the first surface roughness Ra by the second surface roughness Ram is 25% or less. The manufacturing method of the lamination | stacking unit in any one of Claims 5-7 characterized by the above-mentioned. Stacking the multilayer units obtained by the production method according to claim 5 to obtain a ceramic laminate;
Cutting the ceramic laminate to obtain a ceramic green chip;
And a step of firing the ceramic green chip.

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