JP2007294886A - Method of manufacturing stacked electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stacked electronic component such as a stacked ceramic capacitor in which the occurrence of structural defects such as cracks is suppressed even when a dielectric layer is reduced in thickness or has an increasing number of layers. <P>SOLUTION: A plurality of ceramic green sheets and a plurality of electrode layers of a predetermined pattern are alternately stacked to obtain spare laminates Un. Next, the spare laminates Un are dried as a unit such that the spare laminate Un is reduced in weight by 0.1 to 1.0 wt.% from the undried spare laminate Un. After that, a final laminate Uf is cut which has been obtained by stacking the spare laminates Un after the spare laminates Un are dried as a unit, so that a green chip is formed. Next, the green chip is solidified and dried and an amount of a solvent residue in the green chip is adjusted to 1 to 2 wt.%. Thereafter, the solidified and dried green chip is debindered and the debindered green chip is baked. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a multilayer electronic component such as a multilayer ceramic capacitor.

  With recent miniaturization of electronic devices, there has been a demand for miniaturization and large capacity of multilayer ceramic capacitors. In order to reduce the size and increase the capacity of a multilayer ceramic capacitor, the thickness of each dielectric layer is made as thin as possible (thinning), and the number of dielectric layers in a given size is increased as much as possible (multilayering) )It is necessary.

  However, as the dielectric layer becomes thinner and multilayered, cracks (particularly internal cracks) are likely to occur in the obtained capacitor.

  In order to prevent the occurrence of cracks due to the thinning and multilayering of the dielectric layer, as shown in the following Patent Document 1 to Patent Document 5, etc., a step gap portion generated between the internal electrode patterns of a predetermined pattern is blanked. A method of filling with a pattern layer has been proposed. According to these methods, the surface including the internal electrode layer can be planarized.

However, in recent years, with the increase in capacitance and integration, the number of stacked green sheets has increased, and even if a blank pattern layer is formed, delamination between green sheets becomes a problem. It is coming. In addition, stacking misalignment between green sheets has become a problem.
JP 56-94719 A JP-A-3-74820 JP-A-9-106925 JP 2001-126951 A JP-A-2001-358036.

  An object of the present invention is to provide a method of manufacturing a multilayer electronic component such as a multilayer ceramic capacitor in which the occurrence of structural defects such as cracks is suppressed even when the dielectric layer is thinned or multilayered.

In order to achieve the above object, a method for manufacturing a multilayer electronic component according to the present invention includes:
Steps of alternately stacking ceramic green sheets and electrode layers of a predetermined pattern to obtain a pre-laminated body,
A first drying step of unit drying the preliminary laminate,
Cutting the final laminate obtained by stacking the preliminary laminate after the unit is dried, and forming a green chip;
A second drying step for solidifying and drying the green chip;
A step of removing the binder from the solidified and dried green chip,
And firing the green chip after the binder removal treatment.

  Preferably, when the preliminary laminate is unit dried, 0.1 to 1.0 wt%, more preferably 0.2 to 1.0 wt%, more preferably 0.2 to 1.0 wt%, based on the weight of the preliminary laminate before unit drying Preferably, the preliminary laminate is unit-dried so that a weight loss of 0.3 to 0.9 wt% occurs. By drying the unit so that such weight reduction occurs, the rate of occurrence of cracks can be reduced.

  Preferably, when the green chip is solidified and dried, the green chip is adjusted so that a residual solvent amount of the green chip after solidification and drying is 1 to 2 wt%, more preferably 1.1 to 1.5%. Solidify and dry. By performing solidification drying under such conditions, the occurrence rate of cracks can be reduced.

  The solidification drying treatment is preferably performed at a temperature rising rate S1: 10 to 300 ° C / hour, more preferably 20 to 200 ° C / hour, preferably a holding temperature T1: 80 to 200 ° C, more preferably 120 to 170 ° C. And holding time t1 of the holding temperature T1: 4 to 12 hours, more preferably 4 to 8 hours.

The solidification drying treatment may be performed in an atmospheric pressure or a reduced pressure atmosphere.
The solidification drying may be performed without applying pressure or may be performed while applying pressure.

  Preferably, at the time of the binder removal treatment, the green chip is subjected to the binder removal treatment so that the residual carbon amount in the green chip is 0.1 to 0.4 wt%.

  The binder removal treatment is preferably performed at a heating rate S2 of 1 to 15 ° C./hour (excluding 1 ° C./hour), more preferably 5 to 15 ° C./hour, preferably a holding temperature T2 of 400 to 800 ° C. More preferably, it is carried out under conditions of 400 to 700 ° C., preferably a holding time t2 of the holding temperature T2 of 1 to 8 hours, more preferably 2 to 8 hours, particularly preferably 2 to 6 hours.

  The method of the present invention is particularly effective when a ceramic green sheet having a thickness of 3 μm or less is used and the number of laminated layers is 500 or more.

  As a result of intensive studies on the cause of cracks, the present inventors have volatilized residual solvent and residual plasticizer remaining in the green chip through the solidification / drying process and binder removal process. I thought it would cause delamination. That is, as the number of stacked green sheets increases, the residual solvent and residual plasticizer inside the green chip are less likely to volatilize, and these solvents or plasticizers volatilize at a time in the solidification / drying process and binder removal process. Therefore, we thought that delamination is likely to occur.

  Accordingly, the present inventors considered that a predetermined number of green sheets are stacked to form a preliminary laminate, and then the preliminary laminate is dried, and the dried preliminary laminate is stacked to obtain a final laminate. It was. By doing so, it was confirmed by experiments that residual solvents, plasticizers, and the like are less likely to volatilize at a time in the solidification / drying step and the binder removal step of the final laminate, and delamination can be suppressed.

  In addition, the present inventors have found that it is effective to leave a certain amount of solvent in the laminate in order to give the green sheet stackability. On the other hand, it has been found that if the amount of the remaining solvent is too large, it may cause cracks in the chip in the steps after green chip formation (such as a binder removal step and a firing step).

  The present inventors proceeded with research based on such findings. As a result, the process of adjusting the amount of residual solvent to the green chip before the binder removal treatment (solidification drying treatment) is not performed immediately on the green chip formed after the lamination and cutting. It has been found that the application of is effective in suppressing the occurrence of cracks. Specifically, by adjusting the residual solvent amount of the green chip before the binder removal process to an appropriate range, the solvent component does not volatilize rapidly from the green chip in the process after the binder removal, and as a result, firing It has been found that cracks are not generated in the later chip sintered body.

  The multilayer electronic component manufactured by the method of the present invention is not particularly limited, but includes a multilayer ceramic capacitor, a piezoelectric element, a chip varistor, a chip thermistor, a chip inductor, a chip resistor, and other surface mount (SMD) chip electronic components. Etc. are exemplified.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a schematic cross-sectional view of a multilayer ceramic capacitor manufactured by a method for manufacturing a multilayer ceramic electronic component according to an embodiment of the present invention.
2 (A) to 2 (C) are main part cross-sectional views showing an example of a lamination process of a green sheet and an electrode layer,
3 (A) to 3 (C) are main part cross-sectional views showing a continuation process of FIG. 2 (C),
4 (A) to 4 (C) are main part cross-sectional views showing a continuation process of FIG. 3 (C),
5 (A) to 5 (C) are main part cross-sectional views showing a continuation process of FIG. 4 (C),
6 (A) to 6 (C) are main part cross-sectional views showing a continuation process of FIG. 5 (C),
FIG. 7 is a cross-sectional view of an essential part showing a step subsequent to FIG.
8 (A) and 8 (B) are schematic views showing a continuation process of FIG.
FIG. 9 is a schematic view showing stacking deviation.
Overall configuration of multilayer ceramic capacitor

  First, an overall configuration of a multilayer ceramic capacitor will be described as an embodiment of an electronic component 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 internal electrode layer 12 that is alternately stacked is electrically connected to the inside of the first terminal electrode 6 that is formed outside one end of the capacitor body 4. The other internal electrode layers 12 stacked alternately are electrically connected to the inside of the second terminal electrode 8 formed outside the other end of the capacitor body 4.

  In the present embodiment, the internal electrode layer 12 is formed by a transfer method, as will be described in detail later.

  The material of the dielectric layer 10 is not particularly limited, and is made of a dielectric material such as calcium titanate, strontium titanate and / or barium titanate. 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 3 μm or less, and particularly preferably 1.5 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).
Manufacturing method of multilayer ceramic capacitor

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

  First, a dielectric paste (green sheet paste) is prepared in order to manufacture a ceramic green sheet that will form the dielectric layer 10 shown in FIG. 1 after firing.

  The dielectric paste is composed of an organic solvent-based paste obtained by kneading a dielectric material (ceramic powder) and an organic vehicle.

  As the dielectric material, various compounds to be complex oxides and oxides, for example, carbonates, nitrates, hydroxides, organometallic compounds, and the like are appropriately selected and used by mixing. The dielectric material 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 green sheet, it is desirable to use a powder finer than the thickness of the green sheet.

  An organic vehicle is obtained by dissolving a binder resin in an organic solvent. In this embodiment, polyvinyl butyral resin is used as the binder resin used in the organic vehicle. The polymerization degree of the polyvinyl butyral resin is 1000 or more and 1700 or less, preferably 1400 to 1700. The degree of butyralization of the resin is greater than 64% and less than 78%, preferably greater than 64% and 70% or less, and the residual acetyl group content is less than 6%, preferably 3% or less.

  The degree of polymerization of the polyvinyl butyral resin can be measured by, for example, the degree of polymerization of the raw material polyvinyl acetal resin. Further, the degree of butyralization can be measured in accordance with, for example, JISK6728. Furthermore, the amount of residual acetyl groups can be measured according to JISK6728.

  The organic solvent used for the organic vehicle is not particularly limited, and for example, organic solvents such as terpineol, alcohol, butyl carbitol, acetone, and toluene are used. In the present embodiment, the organic solvent preferably includes an alcohol solvent and an aromatic solvent, and the total mass of the alcohol solvent and the aromatic solvent is 100 parts by mass. More than 20 parts by mass. When the content of the aromatic solvent is too small, the sheet surface roughness tends to increase. When the content is too large, paste filtration characteristics deteriorate, and the sheet surface roughness also increases and deteriorates.

  Examples of alcohol solvents include methanol, ethanol, propanol, butanol and the like. Examples of the aromatic solvent include toluene, xylene, benzyl acetate and the like.

  Binder resin should be dissolved and filtered in advance in at least one alcohol solvent of methanol, ethanol, propanol, or butanol, and a dielectric powder and other components should be added to the solution. Is preferred. A binder resin having a high degree of polymerization is difficult to dissolve in a solvent, and the dispersibility of the paste tends to be deteriorated by an ordinary method. In the method of the present embodiment, the paste dispersibility can be improved in order to add the ceramic powder and other components to the solution after dissolving the binder resin having a high degree of polymerization in the above-mentioned good solvent, Generation | occurrence | production of undissolved resin can be suppressed. In addition, in solvents other than the above-mentioned solvents, the solid content concentration cannot be increased, and the change in lacquer viscosity with time tends to increase.

  The dielectric paste may contain additives selected from various dispersants, plasticizers, antistatic agents, dielectrics, glass frit, insulators, and the like as necessary.

  Using this dielectric paste, by a doctor blade method or the like, for example, as shown in FIG. 3 (A), the carrier sheet 30 as the second support sheet is preferably 0.5 to 30 μm, more preferably 0.00. The green sheet 10a is formed with a thickness of about 5 to 10 μm. The green sheet 10 a is dried after being formed on the carrier sheet 30. The drying temperature of the green sheet 10a is preferably 50 to 100 ° C., and the drying time is preferably 1 to 20 minutes. The thickness of the green sheet 10a after drying shrinks to a thickness of 5 to 25% as compared with that before drying. The thickness of the green sheet after drying is preferably 3 μm or less.

  Separately from the carrier sheet 30, as shown in FIG. 2A, a carrier sheet 20 as a first support sheet is prepared, a release layer 22 is formed thereon, and a predetermined pattern is formed thereon. An electrode layer 12a is formed, and before and after that, a blank pattern layer 24 having substantially the same thickness as the electrode layer 12a is formed on the surface of the release layer 22 where the electrode layer 12a is not formed. Note that the blank pattern layer 24 is not necessarily formed when the step due to the pattern of the electrode layer 12a does not have an adverse effect.

  As the carrier sheets 20 and 30, for example, a PET (polyethylene terephthalate) 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 and 30 is not specifically limited, Preferably, it is 5-100 micrometers. The thicknesses of these carrier sheets 20 and 30 may be the same or different.

  The release layer 22 preferably includes the same dielectric particles as the dielectric that constitutes the green sheet 10a shown in FIG. In addition to the dielectric particles, the release layer 22 includes a binder, a plasticizer, and a release agent. The particle size of the dielectric particles may be the same as the particle size of the dielectric particles contained in the green sheet, but is preferably smaller.

  The method for applying the release layer 22 is not particularly limited. However, since it is necessary to form the release layer 22 very thinly, for example, an application method using a wire bar coater or a die coater is preferable.

  The binder for the release layer 22 is made of, for example, an organic material or an emulsion made of acrylic resin, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyolefin, polyurethane, polystyrene, or a copolymer thereof. The binder contained in the release layer 22 may be the same as or different from the binder contained in the green sheet 10a, but is preferably the same.

  Although it does not specifically limit as a plasticizer for the peeling layer 22, For example, a phthalate ester, dioctyl phthalate, adipic acid, phosphate ester, glycols etc. are illustrated. The plasticizer contained in the release layer 22 may be the same as or different from the plasticizer contained in the green sheet 10a.

  The release agent for the release layer 22 is not particularly limited, and examples thereof include paraffin, wax, silicone oil, and the like. The release agent contained in the release layer 22 may be the same as or different from the release agent contained in the green sheet 10a.

  The binder is contained in the release layer 22 in an amount of preferably 2.5 to 200 parts by weight, more preferably 5 to 30 parts by weight, and particularly preferably about 8 to 30 parts by weight with respect to 100 parts by weight of the dielectric particles. .

  The plasticizer is preferably contained in the release layer 22 in an amount of 0 to 200 parts by mass, preferably 20 to 200 parts by mass, and more preferably 50 to 100 parts by mass with respect to 100 parts by mass of the binder.

  The release agent is preferably contained in the release layer 22 at 0 to 100 parts by mass, preferably 2 to 50 parts by mass, and more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the binder.

  After the release layer 22 is formed on the surface of the carrier sheet 20, as shown in FIG. 2A, an electrode layer 12a that will constitute the internal electrode layer 12 after firing is formed on the surface of the release layer 22 in a predetermined pattern. Form. The thickness of the electrode layer 12a is preferably about 0.1 to 2 μm, more preferably about 0.1 to 1.0 μm. The electrode layer 12a may be composed of a single layer, or may be composed of a plurality of layers having two or more different compositions.

  The electrode layer 12a is formed on the surface of the release layer 22 by a thick film forming method using an electrode paste. In order to form the electrode layer 12a on the surface of the release layer 22 by a screen printing method or a gravure printing method which is a kind of thick film method, the following is performed.

  First, an electrode paste is prepared. The electrode paste 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 a conductive material used when manufacturing the electrode paste, Ni, Ni alloy, or a mixture thereof is used. There are no particular restrictions on the shape of such a conductive material, such as a spherical shape or a flake shape, or a mixture of these shapes may be used. The average particle diameter of the conductor material is usually 0.1 to 2 μm, preferably about 0.2 to 1 μm.

  The organic vehicle contains a binder and a solvent. Examples of the binder include ethyl cellulose, acrylic resin, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyolefin, polyurethane, polystyrene, and copolymers thereof, but a butyral system such as polyvinyl butyral is particularly preferable.

  The binder is preferably included in the electrode paste in an amount of 8 to 20 parts by mass with respect to 100 parts by mass of the conductive material (metal powder). As the solvent, any known solvents such as terpineol, butyl carbitol, and kerosene can be used. The solvent content is preferably about 20 to 55% by mass with respect to the entire paste.

  In order to improve adhesion, the electrode paste preferably contains a plasticizer. Examples of the plasticizer include phthalic acid esters such as benzylbutyl phthalate (BBP), adipic acid, phosphoric acid esters, glycols, and the like. The plasticizer is preferably 10 to 300 parts by mass, more preferably 10 to 200 parts by mass with respect to 100 parts by mass of the binder in the electrode paste. In addition, when there is too much addition amount of a plasticizer or an adhesive, there exists a tendency for the intensity | strength of the electrode layer 12a to fall remarkably. In order to improve the transferability of the electrode layer 12a, it is preferable to add a plasticizer and / or a pressure-sensitive adhesive to the electrode paste to improve the adhesion and / or the pressure-sensitive adhesiveness of the electrode paste.

  After or before the electrode paste layer having a predetermined pattern is formed on the surface of the release layer 22 by the printing method, the surface of the release layer 22 on which the electrode layer 12a is not formed is substantially the same thickness as the electrode layer 12a. The blank pattern layer 24 is formed.

  The blank pattern layer 24 shown in FIG. 2A can be formed on the surface of the release layer 22 by a thick film forming method such as a printing method using an electrode level difference absorbing printing paste. When a blank pattern layer (FIG. 2 (A)) is formed on the surface of the release layer 22 by screen printing, which is one type of thick film method, it is performed as follows.

  First, an electrode level difference absorbing printing paste is prepared. The electrode level difference absorbing printing paste is composed of an organic solvent-based paste obtained by kneading a dielectric material (ceramic powder) and an organic vehicle.

  As the dielectric material used when manufacturing the electrode level difference absorbing printing paste, the dielectric material having the same average particle diameter as the dielectric material constituting the green sheet 10a is used. In the electrode level difference absorbing printing paste, dielectric particles (ceramic powder) are contained in an amount of 30 to 50 parts by mass, more preferably 40 to 50 parts by mass with respect to the entire paste. If the content of the ceramic powder is too small, the paste viscosity becomes small and printing is difficult. Moreover, when there is too much content rate of ceramic powder, it exists in the tendency for it to become difficult to make printing thickness thin.

  The organic vehicle contains a binder and a solvent. Examples of the binder include ethyl cellulose, acrylic resin, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, polyolefin, and copolymers thereof, but a butyral system such as polyvinyl butyral is particularly preferable.

  The degree of polymerization of the butyral binder contained in the electrode level difference absorbing printing paste is set to be equal to or higher than the degree of polymerization of the binder contained in the paste for forming the green sheet 10a, preferably high. For example, when the polymerization degree of polyvinyl butyral as a binder contained in the green sheet paste is 1000 to 1700, the binder contained in the electrode level difference absorbing print paste is 1400 or more, more preferably 1700 or more, particularly preferably Polyvinyl butyral or polyvinyl acetal having a degree of polymerization of 2400 or more. Of these, polyvinyl acetal having a polymerization degree of 2000 or more is preferable.

  When the binder of the electrode level difference absorbing printing paste is polyvinyl butyral, it is preferable that the degree of butyral is in the range of 64 to 74 mol%. Moreover, when it is a polyvinyl acetal, it is preferable that the acetalization degree is 66-74 mol%.

  The binder is preferably contained in the electrode paste absorbing print paste in an amount of 3 to 10 parts by mass with respect to 100 parts by mass of the dielectric material. More preferably, 4 to 8 parts by mass are included.

  Any known solvent such as terpineol, butyl carbitol, or kerosene can be used as the solvent. As for the solvent content, about 50-70 mass parts is preferable with respect to the whole paste.

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

  Although there is no limitation in particular as a dispersing agent, For example, polymeric materials, such as ester polymer and carboxylic acid, are used, Preferably the content is 0.25-1. 5 parts by mass, more preferably 0.5 to 1.0 parts by mass is preferably contained.

  The plasticizer is not particularly limited, and for example, phthalic acid esters such as benzylbutyl phthalate (BBP), adipic acid, phosphoric acid esters, glycols, and the like are used. The content thereof is preferably 10 to 200 parts by mass, more preferably 50 to 100 parts by mass with respect to 100 parts by mass of the binder.

  The antistatic agent is not particularly limited. For example, an imidazoline-based antistatic agent is used, and the content thereof is 0.1 to 0.75 parts by mass, more preferably 100 parts by mass of the ceramic powder. It is preferable to contain by 0.25-0.5 mass part.

  As shown in FIG. 2A, this electrode level difference absorbing print paste is printed on the blank pattern portion between the electrode layers 12a. Thereafter, the electrode layer 12a and the blank pattern layer 24 are dried as necessary. The drying temperature is not particularly limited, but is preferably 70 to 120 ° C, and the drying time is preferably 5 to 15 minutes.

  Apart from the carrier sheets 20 and 30, as shown in FIG. 2A, an adhesive layer transfer sheet in which an adhesive layer 28 is formed on the surface of the carrier sheet 26 as a third support sheet is prepared. The carrier sheet 26 is composed of a sheet similar to the carrier sheets 20 and 30.

  The composition of the adhesive layer 28 is the same as that of the release layer 22 except that it does not contain a release agent. That is, the adhesive layer 28 includes a binder, a plasticizer, and a release agent. The adhesive layer 28 may contain the same dielectric particles as the dielectric constituting the green sheet 10a. However, when forming an adhesive layer having a thickness smaller than the particle diameter of the dielectric particles, the dielectric particles It is better not to include. In addition, when dielectric particles are included in the adhesive layer 28, the particle size of the dielectric particles is preferably smaller than the particle size of the dielectric particles included in the green sheet.

  The plasticizer is preferably contained in the adhesive layer 28 in an amount of 0 to 200 parts by mass, preferably 20 to 200 parts by mass, and more preferably 50 to 100 parts by mass with respect to 100 parts by mass of the binder.

  The adhesive layer 28 further contains an antistatic agent, and the antistatic agent contains one of the imidazoline-based surfactants, and the weight-based addition amount of the antistatic agent is the weight of the binder (organic polymer material). It is preferable that it is below the reference addition amount. That is, it is preferable that the antistatic agent is contained in the adhesive layer 28 in an amount of 0 to 200 parts by weight, preferably 20 to 200 parts by weight, and more preferably 50 to 100 parts by weight with respect to 100 parts by weight of the binder.

  The thickness of the adhesive layer 28 is preferably about 0.02 to 0.3 μm, and is preferably thinner than the average particle size of the dielectric particles contained in the green sheet. Moreover, it is preferable that the thickness of the contact bonding layer 28 is 1/10 or less of the thickness of the green sheet 10a.

  If the thickness of the adhesive layer 28 is too thin, the adhesive strength is reduced, and if it is too thick, a gap is easily formed inside the element body after sintering depending on the thickness of the adhesive layer, and the electrostatic capacity corresponding to the volume. Tends to decrease significantly.

  The adhesive layer 28 is formed on the surface of the carrier sheet 26 as the third support sheet by a method such as a bar coater method, a die coater method, a reverse coater method, a dip coater method, or a kiss coater method, and is dried as necessary. . The drying temperature is not particularly limited, but is preferably room temperature to 80 ° C., and the drying time is preferably 1 to 5 minutes.

  In this embodiment, a transfer method is employed to form an adhesive layer on the surfaces of the electrode layer 12a and the blank pattern layer 24 shown in FIG. That is, as shown in FIG. 2B, the adhesive layer 28 of the carrier sheet 26 is pressed against the surfaces of the electrode layer 12a and the blank pattern layer 24 as shown in FIG. By peeling off the carrier sheet 26, the adhesive layer 28 is transferred to the surfaces of the electrode layer 12a and the blank pattern layer 24 as shown in FIG. The transfer of the adhesive layer 28 may be performed on the surface of the green sheet 10a shown in FIG.

  The heating temperature during transfer is preferably 40 to 100 ° C., and the applied pressure is preferably 0.2 to 15 MPa. The pressurization may be a pressurization or a calender roll, but is preferably performed by a pair of rolls.

  Thereafter, the electrode layer 12a is bonded to the surface of the green sheet 10a formed on the surface of the carrier sheet 30 shown in FIG. For that purpose, as shown in FIG. 3B, the electrode layer 12a and the blank pattern layer 24 of the carrier sheet 20 are pressed together with the carrier sheet 20 onto the surface of the green sheet 10a via the adhesive layer 28, and heated and pressurized. As shown in FIG. 3C, the electrode layer 12a and the blank pattern layer 24 are transferred to the surface of the green sheet 10a. However, since the carrier sheet 30 on the green sheet side is peeled off, when viewed from the green sheet 10 a side, the green sheet 10 a is transferred to the electrode layer 12 a and the blank pattern layer 24 via the adhesive layer 28.

  The heating and pressurization at the time of transfer may be pressurization / heating with a press or pressurization / heating with a calender roll, but is preferably performed with a pair of rolls. The heating temperature and pressure are the same as when the adhesive layer 28 is transferred.

  2A to 3C, a single layer of electrode layer 12a having a predetermined pattern is formed on a single green sheet 10a. In order to laminate the green sheet 10a on which the electrode layer 12a is formed, for example, the steps shown in FIGS. 4A to 6C may be repeated. 4 (A) to 6 (C), members that are the same as those shown in FIGS. 3 (A) to 4 (C) are denoted by the same reference numerals, and description thereof is partially omitted. .

  First, as shown in FIGS. 4A to 4C, the adhesive layer 28 is transferred to the counter electrode layer side surface (back surface) of the green sheet 10a. Thereafter, as shown in FIGS. 5A to 5C, the electrode layer 12 a and the blank pattern layer 24 are transferred to the back surface of the green sheet 10 a through the adhesive layer 28.

  Next, as shown in FIGS. 6A to 6C, the green sheet 10 a is transferred to the surfaces of the electrode layer 12 a and the blank pattern layer 24 via the adhesive layer 28. Thereafter, by repeating these transfers, as shown in FIG. 7, a preliminary laminated body Un in which the electrode layers 12a and the green sheets 10a are alternately laminated is obtained.

  Note that without adopting the steps shown in FIGS. 5C to 6C, the lower carrier sheet 20 is not peeled off from the step shown in FIG. 5B, but the upper carrier sheet is peeled off. On top of that, a laminate unit U1 shown in FIG. 4C may be laminated. Thereafter, the upper carrier sheet 20 is peeled off again, and the laminate unit U1 shown in FIG. 4C is laminated thereon, and the operation of peeling the upper carrier sheet 20 again is repeated. As shown in FIG. 4, a pre-laminated body Un in which the electrode layers 12a and the green sheets 10a are alternately laminated is obtained. The method of stacking (stacking) the stacked unit U1 shown in FIG. 4C to obtain the preliminary stacked body Un is superior in stacking work efficiency.

  In the present embodiment, the number of green sheets 10a stacked in the preliminary stacked body Un shown in FIG. 7 is not particularly limited, but is preferably 10 to 100.

  In this embodiment, next, either the upper carrier sheet 20 or the lower carrier sheet 30 in the preliminary laminate Un shown in FIG. 7 is peeled off, and in this state, the preliminary laminate Un is dried (unit drying). )I do. The drying temperature during the unit drying process is preferably 80 to 120 ° C. The drying time is, for example, 15 minutes to 3 hours.

  At the time of unit drying, 0.1 to 1.0 wt%, more preferably 0.2 to 1.0 wt%, more preferably 0.3 to 0.9 wt%, based on the weight of the preliminary laminate Un before the unit is dried. The pre-laminate Un is unit dried so that a weight loss of% occurs. By drying the unit so that such weight reduction occurs, the rate of occurrence of cracks can be reduced.

  As shown in FIG. 8 (A) and FIG. 8 (B), the dried pre-laminated body Un is transported onto the lower mold of the temporary press device by the transport plate 50 together with the carrier sheet 20 or 30. Therefore, the pressing mechanism 52 presses the preliminary laminated body Un that has been temporarily placed. The pressure at the time of temporary placement of the preliminary laminated body Un by the transport plate 50 is a pressure of 0.1 MPa or more, preferably 0.5 MPa or more.

  At the time of temporary placement of the preliminary laminate Un by the transport plate 50, the transport plate 50 is heated and the preliminary stack Un is heated to a predetermined temperature. The heating temperature is preferably 50 to 85 ° C. Although the pressurization time at the time of temporary placement is not particularly limited, it is usually 1 to 60 seconds, preferably about 1 to 30 seconds.

  The pre-laminated body Un to be stacked is always subjected to a unit drying process before being temporarily placed. Although the total number of stacks of the preliminary laminate Un is not particularly limited, it is preferably about 10 to 100. As the total number of the stacked stacks of the preliminary stacked bodies Un increases, the total number of stacked final stacked bodies Uf increases.

  When the preliminary laminated body Un is laminated until the final laminated body Uf is reached, the transport plate shown in FIG. 8B moves in the horizontal direction from above the final laminated body Uf, and is not shown in the figure. The upper die is pulled down toward the lower die 40, and a temporary press is performed.

  The pressure at the time of temporary pressing is a pressure of 5 MPa or more, preferably 5 to 10 MPa. If the pressure of the temporary press is too low, it tends to be difficult to maintain the shape as a laminate in subsequent steps (for example, a cutting step). Moreover, when the pressure of a temporary press is too large, there exists a tendency for the deformation | transformation of a laminated body to become large, and it is not preferable.

  Further, it is preferable that the lower mold 40 and the upper mold are heated to a predetermined temperature during the temporary pressing. Although the heating temperature at the time of temporary press is not specifically limited, Preferably it is 50-90 degreeC. The pressurization time during temporary pressing is preferably 1 to 60 seconds.

  In addition, when the press pressure capability of the conveyance board 50 is high, you may temporarily press the final laminated body Uf using the conveyance board 50, without using a temporary press apparatus.

  Thereafter, the laminate is cut into a predetermined size to form a green chip. The green chip is subjected to a solidification drying process, a binder removal process, and a baking process, and a heat treatment is performed to reoxidize the dielectric layer.

  When the green chip is solidified and dried, the green chip is solidified and dried so that the residual solvent amount of the green chip after solidification and drying is 1 to 2 wt%, more preferably 1.1 to 1.5%. By performing solidification drying under such conditions, the occurrence rate of cracks can be reduced.

  The reason why the residual solvent amount of the green chip before the binder removal process described later is adjusted to 1 to 2 wt% is that if it is less than 1 wt%, the strength of the green chip is lowered and cracks are likely to occur in the subsequent process. . On the other hand, if it exceeds 2 wt%, there is no problem in strength, but the amount of solvent that volatilizes in the subsequent process increases, and it is easy to induce cracks in the chip during binder removal and firing. It is.

Specifically, the solidification drying treatment is preferably performed under the following conditions.
Temperature rising rate S1: 10 to 300 ° C./hour, especially 20 to 200 ° C./hour,
Holding temperature T1: 80 to 200 ° C, particularly 120 to 170 ° C,
T1 holding time t1: 4-12 hours, especially 4-8 hours.

  If the rate of temperature increase is too fast (= the temperature is rapidly increased), the solvent and the resin vaporize (sublimate) and there is a possibility that the original shape of the green chip cannot be maintained due to rapid expansion. On the other hand, if the rate of temperature rise is too slow, too much solvent component will escape from the chip and cracks will occur.

  If the holding temperature is too low, it is difficult for the solvent component to escape from the chip, resulting in an increase in the amount of residual solvent, and as a result, cracking occurs in the chip after firing. On the other hand, if the holding temperature is too high, a large amount of the solvent component is removed from the chip, and the resin is also decomposed, so that the strength of the green chip is greatly reduced and the shape may not be held.

  If the holding time of the holding temperature is too low or too high, the solvent component in the chip does not fall within the proper range, the chip strength is insufficient, or cracks occur in the chip after firing.

  In addition, the atmosphere when solidifying and drying is not particularly limited. For example, it may be performed in air or under reduced pressure (including a vacuum state). By performing solidification drying under reduced pressure, the retention temperature during solidification drying can be lowered and the retention time can be shortened.

  Next, the green chip after solidification drying is subjected to binder removal processing, and the residual carbon amount in the chip is adjusted to 0.1 to 0.4 wt%, preferably 0.1 to 0.2 wt%. If the amount of residual carbon in the green chip after debuy exceeds 0.4 wt%, cracks are likely to occur in the sintered body after firing, which is not preferable.

In the present invention, the binder removal treatment is preferably performed under the following conditions.
Temperature rising rate S2: 1 to 15 ° C./hour (excluding 1 ° C./hour), preferably 5 to 15 ° C./hour,
Holding temperature T2: 400 to 800 ° C., preferably 400 to 700 ° C.
Holding time t2 of holding temperature T2: 1 to 8 hours, more preferably 2 to 8 hours, particularly preferably 2 to 6 hours. Atmosphere: Mixed gas of humidified N ₂ and H ₂ .

  If the rate of temperature increase is too fast (= the temperature is rapidly increased), the solvent and the resin vaporize (sublimate) and there is a possibility that the original shape of the green chip cannot be maintained due to rapid expansion. On the other hand, if the rate of temperature rise is too slow, there is a possibility that the minimum carbon necessary for maintaining the original shape of the chip will be lost and the original shape of the chip cannot be maintained.

  If the holding temperature is too low, the amount of residual carbon in the chip increases, and as a result, cracks occur in the chip after firing. On the other hand, if the holding temperature is too high, the amount of carbon remaining in the chip is excessively reduced, so that the strength of the green chip is significantly reduced and the shape may not be held.

  If the holding time of the holding temperature is too low or too high, the amount of residual carbon in the chip does not fall within the proper range, the chip strength is insufficient, or cracks occur in the chip after firing.

  The green chip after the debuying is then subjected to a firing process, and then a heat treatment is performed to reoxidize the dielectric layer.

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 ⁻² to 10 ⁻⁸ Pa. If the above range is exceeded, the internal electrode layer tends to oxidize, and if the oxygen partial pressure is too low, the electrode material of the internal electrode layer tends to abnormally sinter and tend to break.

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

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

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

  In the method for manufacturing a multilayer ceramic capacitor according to the present embodiment, a predetermined number of green sheets 10a are stacked to form a preliminary stacked body Un, and then the preliminary stacked body Un is dried, and the dried preliminary stacked body Un is stacked. Thus, the final laminate Uf is obtained. By doing so, the residual solvent or plasticizer is less likely to volatilize at a time in the solidification drying process and the binder removal process of the final laminate Un, and delamination can be suppressed.

  Moreover, in this embodiment, since the residual solvent amount after the unit drying of the preliminary laminated body Un is in a predetermined range, it is not excessively dried, the stacking property is sufficient, and the final laminated body is obtained by pressing. In this case, as shown in FIG. 9, the stacking deviation ΔD between the preliminary stacks Un can also be suppressed.

  Further, in the present embodiment, the green chip formed after lamination and cutting is not immediately subjected to the binder removal process, but the residual solvent amount is adjusted with respect to the green chip before the binder removal process. Generation of cracks is suppressed. Specifically, by adjusting the residual solvent amount of the green chip before the binder removal process to an appropriate range, the solvent component does not volatilize rapidly from the green chip in the process after the binder removal, and as a result, firing Cracks are not generated in the later chip sintered body.

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

Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.
Example 1
Preparation of green sheet paste

BaTiO ₃ powder (BT-02 / Sakai Chemical Industry Co., Ltd.) was used as a starting material for the ceramic powder. (Ba _0.6 Ca _0.4 ) SiO ₃ : 1.48 parts by mass, Y ₂ O ₃ : 1.01 parts by mass, MgCO ₃ : 0.72% by mass with respect to 100 parts by mass of this BaTiO ₃ powder. , Cr ₂ O ₃ : 0.13 mass%, and V ₂ O ₅ : 0.045 mass% were prepared ceramic powder subcomponent additives.

First, only the minor component additive was mixed with a ball mill to form a slurry. That is, auxiliary components (total amount 8.8 g) and ethanol / n-propanol 1: 1 solvent (16 g) were preliminarily pulverized with a ball mill for 20 hours. Next, with respect to BaTiO ₃ : 191.2 g, as a plasticizer component, a preliminary pulverized slurry of additive additives, ethanol: 38 g, n-propanol: 38 g, xylene: 28 g, mineral spirit: 14 g DOP (dioctyl phthalate): 6 g and polyethylene glycol-based nonionic dispersant (HLB = 5-6): 1.4 g as a dispersant were added. As a binder resin, BH6 (polyvinyl butyral resin / PVB) 15% lacquer (Sekisui Chemical BH6 is dissolved in ethanol / n-propanol = 1: 1) as a solid content is used as a binder resin. A mass% was added (80 g as a lacquer addition amount). Then, a ceramic paste (green sheet paste) was obtained by ball milling for 20 hours. In addition, as the polyethylene glycol-based nonionic dispersant (HLB = 5 to 6) as a dispersant, a block polymer of polyethylene glycol and a fatty acid ester was used.

  The degree of polymerization of the polyvinyl butyral resin as the binder resin was 1400, the degree of butyralization was 69% ± 3%, and the amount of residual acetyl groups was 3 ± 2%. This binder resin was contained in the ceramic paste at 6 parts by mass with respect to 100 parts by mass of ceramic powder (including ceramic powder subcomponent additives). Further, when the total volume of the ceramic powder, the binder resin, and the plasticizer in the ceramic paste was 100% by volume, the volume ratio occupied by the ceramic powder was 67.31% by volume. Moreover, the mass ratio of the ceramic powder in the whole paste was 49 mass%.

  Moreover, DOP as a plasticizer was contained in the ceramic paste at 50 parts by mass with respect to 100 parts by mass of the binder resin. The water was contained in an amount of 2 parts by mass with respect to 100 parts by mass of the ceramic powder. The polyethylene glycol-based nonionic dispersant as the dispersant was contained in an amount of 0.7 parts by mass with respect to 100 parts by mass of the ceramic powder.

Further, in the paste, 5 parts by mass of mineral spirit, which is at least one of hydrocarbon solvents, industrial gasoline, kerosene, and solvent naphtha, is added to 100 parts by mass of the ceramic powder. It was. Further, the paste contains an alcohol solvent and an aromatic solvent as a solvent, the total mass of the alcohol solvent and the aromatic solvent is 100 parts by mass, and toluene as an aromatic solvent is 15 masses. Department was included.
Green sheet production

The paste obtained as described above was applied by a wire bar coater to a thickness of 1.2 μm on a PET film as a support film shown in FIG. 3 (A) and dried to produce a green sheet 10a. The coating speed was 50 m / min, and the drying conditions were a temperature in the drying furnace of 60 ° C. to 70 ° C. and a drying time of 2 minutes.
Release layer paste

A paste was prepared in the same manner as the green sheet paste except that BaTiO ₃ in the green sheet paste was changed to BT-01. The paste was ethanol: propanol: xylene (42.5: 42.5: 15). 1) diluted with a mixed solvent of 5) was used as a peeling paste.
Adhesive layer paste

An organic vehicle was used as the adhesive layer paste. Specifically, a mixed solution of 50 parts by mass of bis (2-hexylhexyl) phthalate DOP as a plasticizer and 900 parts by mass of MEK as a plasticizer is further diluted 10 times with MEK with respect to 100 parts by mass of polyvinyl butyral resin. Thus, an adhesive layer paste was obtained.
Internal electrode paste (transferred electrode layer paste)

For 100 parts by mass of Ni particles having an average particle size of 0.2 μm,
BaTiO ₃ powder (BT-01 / Sakai Chemical Industry Co.): 20 parts by weight,
Organic vehicle: 58 parts by mass (8 parts by mass of polyvinyl butyral resin dissolved in 92 parts by mass of terpineol),
Bis (2-hexylhexyl) phthalate DOP as a plasticizer: 50 parts by mass
Terpineol: 5 parts by mass,
Dispersant: 1 part by weight,
Acetone: 45 parts by weight
Was added and kneaded with three rolls to form a slurry for internal electrodes.
Production of electrode paste absorbing paste

  The same ceramic powder and subcomponent additives used for the green sheet paste were prepared so as to have the same blending ratio.

To the ceramic powder and auxiliary component additive (150 g), an ester polymer dispersant (1.5 g), terpineol (5 g), acetone (60 g), and dioctyl phthalate (5 g) as a plasticizer are added. And mixed for 4 hours. Next, 8% lacquer of 8% lacquer (polyvinyl butyral resin having a polymerization degree of 1450 and a butyralization degree of 69 mol% ± 3%) manufactured by Sekisui Chemical Co., Ltd. was added to this mixed solution. Mass% and terpineol 92 mass%) was added in an amount of 120 g and mixed for 16 hours. Then, the excess solvent acetone was removed, and paste was produced by adding 40-100g of terpineol as viscosity adjustment.
Green sheet formation, adhesive layer and electrode layer transfer

  First, using the dielectric green sheet paste, a green sheet having a thickness of 1.2 μm was formed on a PET film (second support sheet) using a wire bar coater. Next, in order to form a release layer on another PET film (first support sheet), the above release layer paste is applied and dried with a wire bar coater to form a 0.2 μm release layer. did.

  Electrode layer 12a and blank pattern layer 24 were formed on the surface of the release layer. The electrode layer 12a was formed with a thickness of 1 μm by a printing method using the internal electrode paste. The blank pattern layer 24 was formed with a thickness of 1 μm by a printing method using the above electrode level difference absorbing printing paste. In printing using the electrode level difference absorbing printing paste, no inconvenience such as the paste flowing out of the mesh of the printing plate making was observed.

  Further, an adhesive layer 28 was formed on another PET film (third support sheet). The adhesive layer 28 was formed with a thickness of 0.1 μm by the wire bar coater using the above adhesive layer paste.

  First, the adhesive layer 28 was transferred to the surfaces of the electrode layer 12a and the blank pattern layer 24 by the method shown in FIG. At the time of transfer, a pair of rolls were used, the pressure was 1 MPa, the temperature was 80 ° C., and it was confirmed that transfer could be performed satisfactorily.

Next, the internal electrode layer 12a and the blank pattern layer 24 were adhered (transferred) to the surface of the green sheet 10a through the adhesive layer 28 by the method shown in FIG. At the time of transfer, a pair of rolls were used, the pressure was 1 MPa, the temperature was 80 ° C., and it was confirmed that transfer could be performed satisfactorily.
Unit drying

  Next, the internal electrode layer 12a and the green sheet 10a were successively laminated by the method shown in FIGS. 4 to 7 to form a plurality of preliminary laminated bodies Un. The number of laminated green sheets 10a in each preliminary laminated body Un was 30 layers. Next, each preliminary laminate was subjected to unit drying treatment.

  Unit drying treatment conditions were 100 ° C. and 120 minutes. The residual solvent amount of the pre-lamination body before unit drying and the residual solvent amount of the pre-lamination body after unit drying were measured, respectively. The residual solvent amount in the pre-laminated body after the unit was dried was 3.8 wt%.

  The amount of residual solvent was measured by performing weight reduction with heating at 220 ° C. for 8 hours and gas chromatograph mass spectrometry, specifying the ratio of solvent components, and setting it to 100%. On the other hand, weight reduction and analysis were performed for each condition, and the residual solvent amount was calculated therefrom.

  Next, the preformed body Un after the unit was dried was temporarily placed on the lower mold 40 using the transport plate 50 shown in FIG. The pressure at the time of temporary placement was 0.15 MPa, the heating temperature was 60 ° C., and the pressurization time was 30 seconds. This preliminary laminated body Un was laminated so that the total number of laminated layers was 900, and temporary pressing was performed to obtain a final laminated body Uf. The applied pressure at the time of temporary pressing was 5.9 MPa, the heating temperature was 50 ° C., and the pressing time was 30 seconds.

Next, the final laminated body Uf was cut into a predetermined size and subjected to solidification drying treatment, binder removal treatment, firing and annealing (heat treatment) to produce a chip-shaped sintered body. The size of each chip after firing was 3.2 mm × 1.6 mm × 1.6 mm.
Solidification drying, solvent amount measurement

Next, the obtained green chip was solidified and dried.
Solidification drying is
Temperature increase rate S1: 10 to 300 ° C./hour (see table),
Holding temperature T1: 80-200 ° C. (see table),
Holding time t1: 4 to 12 hours (see table),
Atmospheric gas: performed in air or in vacuum (see table).

  Then, the residual solvent amount (after solidification drying) of the chip was measured. The amount of residual solvent was measured in the same manner as before solidification drying. The results are shown in Table 1.

Further, the fixing strength of the green chip after solidification drying was measured. The fixing strength was measured by supporting both sides of the tip end, applying a blade to the upper surface, and applying pressure. In this example, a non-defective product having a fixing strength of 65 N or more was determined. The results are shown in Table 1.
Binder removal and carbon content measurement

Next, binder removal processing was performed on the green chip after solidification drying.
Binder removal
Temperature rising rate S2: 15 ° C./hour,
Holding temperature T2: 600 ° C.
Holding time t2: 2 hours
Atmospheric gas: A mixed gas of humidified N ₂ and H ₂ ,
I went there.

Thereafter, the residual carbon amount of the chip (after debinding) was measured. The amount of residual carbon was measured using a carbon / sulfur analyzer (EMIA520 manufactured by Horiba, Ltd.). This analyzer burns an original sample (chip) with an oxygen stream generated by high-frequency heating, and measures the amount of carbon by infrared absorption. The results are shown in Table 1.
Production of sintered body

Next, the green chip after the binder removal treatment was fired and annealed (heat treatment) to produce a chip-shaped sintered body.
Firing is
Temperature increase rate: 300 ° C / hour,
Holding temperature: 1200 ° C,
Retention time: 2 hours
Cooling rate: 200 ° C./hour,
Atmosphere gas: mixed gas of _{N 2} gas and _H 2 controlled to a dew point of 20 ℃ (5%), with was conducted.

Annealing (reoxidation)
Temperature increase rate: 300 ° C / hour,
Holding temperature: 1050 ° C.
Retention time: 2 hours
Cooling rate: 300 ° C./hour,
Atmosphere gas was carried out in N ₂ gas, controlled to a dew point 20 ° C..
The humidification of the atmospheric gas was performed using a wetter at a water temperature of 0 to 75 ° C.

Next, after polishing the end face of the chip-shaped sintered body by sand blasting, an In—Ga alloy paste is applied to the end, and then firing is performed to form an external electrode, and the multilayer ceramic shown in FIG. A capacitor sample was obtained.
Crack generation rate

  The crack generation rate was evaluated for the obtained multilayer ceramic capacitor samples. The crack generation rate (%) was calculated as follows. First, the appearance of 1000 capacitor samples was observed with an optical microscope (manufactured by Nikon, UFX-II) to confirm the presence or absence of cracks, and 30 capacitor samples with no cracks were selected. Next, after filling these 30 capacitor samples with resin and polishing 2 mm in the 4.5 mm direction, the presence or absence of internal cracks was examined with an optical microscope, and the number of capacitor samples with internal cracks was determined as the total number ( Divided by 30) and expressed as a percentage. In this example, those having a crack occurrence rate of 10% or less were counted as non-defective products. The results are shown in Table 1.

Evaluation 1

From Table 1, the following can be understood.
First, when T1 and t1 during solidification drying and the atmosphere are fixed and S1 is changed, if S1 is too slow, the amount of solvent in the chip after solidification drying becomes too small. As a result, after firing The crack generation rate of the chip sintered body becomes larger (Sample 1). On the other hand, if S1 is too early, the amount of solvent in the chip after solidification and drying becomes too large, and as a result, the crack generation rate of the sintered chip after firing becomes large (samples 9 and 10). On the other hand, when S1 is in an appropriate range, the solvent amount of the chip after solidification and drying is controlled to 1 to 2 wt%, and as a result, the crack generation rate of the sintered chip body after firing can be reduced ( Samples 2-8).

  Next, when S1 and t1 and the atmosphere at the time of solidification drying are fixed and T1 is changed, if T1 is too low, the amount of solvent in the chip after solidification drying becomes too large. The crack generation rate of the later chip sintered body increases (samples 11 and 12). Conversely, if T1 is too high, the amount of solvent in the chip after solidification and drying is too small, and as a result, the crack generation rate of the sintered chip after firing is increased (sample 17). On the other hand, when T1 is in the proper range, the solvent amount of the chip after solidification and drying is controlled to 1 to 2 wt%, and as a result, the crack generation rate of the sintered chip body after firing can be reduced ( Samples 4, 13-16).

  Next, when S1 and T1 and the atmosphere at the time of solidification drying are fixed and t1 is changed, if t1 is too short, the amount of solvent in the chip after solidification drying becomes too large, and as a result, firing is performed. The crack generation rate of the later chip sintered body is increased (sample 21). Conversely, if t1 is too long, the amount of solvent in the chip after solidification and drying is too small, and as a result, the crack generation rate of the sintered chip after firing is increased (sample 23). On the other hand, when t1 is in the proper range, the solvent amount of the chip after solidification and drying is controlled to 1 to 2 wt%, and as a result, the crack generation rate of the sintered chip body after firing can be reduced ( Sample 4,22).

  Sample 24 was solidified and dried in a reduced-pressure atmosphere. It has been confirmed that the same effect can be obtained even when performed in a reduced pressure atmosphere.

If solidification drying is not performed (sample 25), the crack generation rate becomes 100%. Further, if unit drying is not performed (sample 26), even if solidification drying is performed, the crack generation rate does not become 10% or less.
Example 2

  A sintered body was obtained in the same manner as in Example 1 except that the binder removal conditions for the green chip after solidification drying were changed as follows, and the crack amount was investigated. A chip capacitor having a crack occurrence rate of 10% or less was counted as a non-defective product. The results are shown in Table 2.

De-buy condition / temperature increase rate: 5 to 15 ° C./hour,
-Detension holding temperature: 400-800 ° C
-Retention time: 2-8 hours.

Evaluation 2

From Table 2, the following can be understood.
First, focusing on the case where T2 and t2 at the time of binder removal are fixed and the temperature increase rate S2 is changed, if S2 is too slow, the carbon amount of the chip after binder removal becomes too small, resulting in firing. The crack generation rate of the later chip sintered body is increased (sample 31). On the other hand, if the heating rate S2 is too high, a gas for removing the binder is generated abruptly and causes cracking (sample 34). On the other hand, if S2 is in the proper range, the carbon content of the chip after debinding is controlled to 0.1 to 0.4 wt%, and as a result, the crack generation rate of the sintered chip body after firing is reduced. (Samples 4, 32, 33).

  Next, when S2 and t2 at the time of binder removal are fixed and T2 is changed, if T2 is too low, the amount of carbon in the chip after binder removal becomes too large. As a result, after firing, The crack generation rate of the chip sintered body is increased (sample 41). On the other hand, if T2 is too high, the amount of solvent in the chip after debinding is too small, and as a result, the crack generation rate of the sintered chip after firing is increased (sample 44). On the other hand, if T2 is in the proper range, the carbon content of the chip after binder removal is controlled to 0.1 to 0.4 wt%, and as a result, the crack generation rate of the sintered chip after firing is reduced. (Samples 4, 42, 43).

Next, when S2 and T2 at the time of binder removal are fixed and t2 is changed, if t2 is too short, the carbon amount of the chip after binder removal becomes too large, and as a result, after firing The crack generation rate of the chip sintered body increases (sample 51). Conversely, if t2 is too long, the carbon content of the chip after debinding is too small, and as a result, the crack generation rate of the sintered chip after firing is increased (sample 55). On the other hand, if t2 is in the proper range, the carbon content of the chip after binder removal is controlled to 0.1 to 0.4 wt%, and as a result, the crack generation rate of the sintered chip body after firing is reduced. (Samples 4, 52-54).
Example 3

  A sintered body was obtained in the same manner as in Example 1 except that pressure was applied as shown in Table 3 when the green chip was solidified and dried, and the amount of cracks was examined. A chip capacitor having a crack occurrence rate of 10% or less was counted as a non-defective product. The results are shown in Table 3.

  In Table 3, the chip deformation amount (%) after solidification drying is a result of measuring how much the chip dimension after solidification drying is deformed with respect to the chip dimension before solidification drying. This deformation is preferably 1% or less. When the amount of chip deformation exceeds 1%, it is difficult to make the chip size uniform, and the chip size varies.

Evaluation 3

As shown in Table 3, it was confirmed that the rate of occurrence of cracks can be reduced by applying pressure during solidification drying. However, if the pressure is too strong, the amount of deformation of the chip increases, which is not preferable. Therefore, the pressure is preferably less than 3 MPa, more preferably 2 MPa or less.
Example 4

  Except for the following, a sintered body was produced in the same manner as in Example 1, and the crack generation rate was determined.

  4 to 7, the internal electrode layer 12a and the green sheet 10a were sequentially stacked to form a plurality of preliminary stacked bodies Un. The number of stacked green sheets 10a in each preliminary laminate Un was 10. Next, each preliminary laminate was subjected to unit drying treatment.

  Unit drying treatment conditions were such that the drying temperature was 100 ° C., and the drying time was changed according to Table 4 to 0 hours, 2 hours, 4 hours, 6 hours, 8 hours, and 10 hours.

Next, the preformed body Un after the unit was dried was temporarily placed on the lower mold 40 using the transport plate 50 shown in FIG. Temporary placement conditions are
Pressure: 0.15 MPa,
Heating temperature: 60 ° C
Pressurization time: 30 seconds,
Met. This preliminary laminated body Un was laminated so that the total number of laminated layers was 500, and temporary pressing was performed to obtain a final laminated body Uf. Temporary press conditions are
Applied pressure: 5.9 MPa
Heating temperature: 50 ° C
Pressurization time: 1 second
Met.

  Next, the final laminated body Uf was cut into a predetermined size and subjected to solidification drying treatment, binder removal treatment, firing and annealing (heat treatment) to produce a chip-shaped sintered body. The size of each chip after firing was set to 1.6 × 3.2 × 1.6 mm.

Next, the obtained green chip was solidified and dried. The solidification drying process
Temperature rising rate S1: 50 ° C./h,
Holding temperature T1: 160 ° C.
Holding time t1: 4 hr,
Atmospheric gas: In air,
It performed on condition of this.

  Then, the residual solvent amount of the chip | tip was measured about the green chip | tip after solidification drying. The results are shown in Table 4.

Next, binder removal processing was performed on the green chip after solidification drying.
Binder removal
Temperature rising rate S1: 15 ° C./h,
Holding temperature T1: 600 ° C.
Holding time t1: 2 hr,
Atmospheric gas: A mixed gas of N ₂ gas and H ₂ (5%) controlled at a dew point of 20 ° C.
It performed on condition of this.

  The green chip subjected to the binder removal treatment was fired in the same manner as in Example 1, and the crack generation rate of the obtained sintered body was measured. The results are shown in Table 4.

Evaluation 4

From Table 4, the following could be confirmed.
At the time of unit drying, 0.1 to 1.0 wt%, more preferably 0.2 to 1.0 wt%, more preferably 0.3 to 0.9 wt%, based on the weight of the preliminary laminate Un before the unit is dried. %, It was possible to reduce the occurrence rate of cracks by subjecting the pre-laminated body Un to unit drying (Samples 111 to 113).

Further, when the green chip is solidified and dried, the green chip is solidified and dried so that the residual solvent amount of the green chip after solidification and drying is 1 to 2 wt%, more preferably 1.1 to 1.5%. Thus, it was confirmed that the occurrence rate of cracks can be reduced.
Example 5

  For Sample 120 to Sample 124, the unit drying temperature was set to 100 ° C., the drying time was set to 2 hours, and the total number of layers was changed to 300, 500, 700, 900, and 1000 as shown in Table 5. The crack occurrence rate was measured in the same manner as in No. 4. Samples 130 to 134 were not subjected to unit drying, and the total number of layers was changed as shown in Table 5.

Evaluation 5

From Table 5, the following could be confirmed.
Comparing the unit drying conditions with and without the case, comparing the crack generation rate when the total number of layers is the same, the crack generation rate is smaller when unit drying is performed in all cases. It was confirmed that it was possible (samples 120 to 124). It was also confirmed that the greater the total number of layers, the greater the effect of reducing the crack generation rate. In particular, it was confirmed that the crack generation rate can be suppressed even when the total number of laminated layers is 1000.
Example 6

  For sample 180, the crack generation rate was set in the same manner as in Example 4 except that the chip size was changed to 0.8 × 1.6 × 0.8 mm, unit drying was performed at 100 ° C. for 2 hours, and the total number of layers was 250. Examined. For the sample 181, the crack occurrence rate was examined in the same manner as the sample 180 except that unit drying was not performed. The results are shown in Table 6.

Evaluation 6

From Table 6, the following could be confirmed.
Even when the chip size was further reduced, it was confirmed that the rate of occurrence of cracks was smaller when the unit was dried compared to when the unit was dried and when the unit was not dried (Sample 180, 181).

FIG. 1 is a schematic cross-sectional view of a multilayer ceramic capacitor manufactured by a method for manufacturing a multilayer ceramic electronic component according to an embodiment of the present invention. FIG. 2A to FIG. 2C are cross-sectional views of a main part showing an example of a lamination process of a green sheet and an electrode layer. FIG. 3A to FIG. 3C are cross-sectional views of relevant parts showing a step subsequent to FIG. FIGS. 4A to 4C are cross-sectional views of relevant parts showing steps subsequent to FIG. FIG. 5A to FIG. 5C are cross-sectional views of relevant parts showing a step subsequent to FIG. 6 (A) to 6 (C) are cross-sectional views of relevant parts showing a step subsequent to FIG. 5 (C). FIG. 7 is a fragmentary cross-sectional view showing a step continued from FIG. FIG. 8A and FIG. 8B are schematic views showing a continuation process of FIG. FIG. 9 is a schematic view showing stacking deviation.

Explanation of symbols

2 ... Multilayer ceramic capacitor 4 ... Capacitor body 6, 8 ... Terminal electrode 10 ... Dielectric layer 10a ... Green sheet 12 ... Internal electrode layer 12a ... Electrode layer 20 ... Carrier sheet (first support sheet)
22 ... Release layer 24 ... Blank pattern layer 26 ... Carrier sheet (third support sheet)
28 ... Adhesive layer 30 ... Carrier sheet (second support sheet)
40 ... Lower mold 50 ... Conveying plate Un ... Preliminary laminate Uf ... Final laminate

Claims (10)

Steps of alternately stacking ceramic green sheets and electrode layers of a predetermined pattern to obtain a pre-laminated body,
A first drying step of unit drying the preliminary laminate,
Cutting the final laminate obtained by stacking the preliminary laminate after the unit is dried, and forming a green chip;
A second drying step for solidifying and drying the green chip;
A step of removing the binder from the solidified and dried green chip,
And a step of firing the green chip after the binder removal process.   Claims: When the preliminary laminate is unit dried, the preliminary laminate is unit-dried so that a weight reduction of 0.1 to 1.0 wt% with respect to the weight of the preliminary laminate before unit drying occurs. Item 2. A method for manufacturing a multilayer electronic component according to Item 1.   3. The multilayer electronic component according to claim 1, wherein when the green chip is solidified and dried, the green chip is solidified and dried so that a residual solvent amount of the green chip after solidification and drying is 1 to 2 wt%. Manufacturing method.   The solidification drying treatment is performed under conditions of a temperature rising rate S1: 10 to 300 ° C / hour, a holding temperature T1: 80 to 200 ° C, and a holding time t1: 4 to 12 hours of the holding temperature T1. The manufacturing method of the multilayer electronic component in any one.   The manufacturing method of the multilayer electronic component according to claim 4, wherein the solidification drying process is performed in an atmospheric pressure.   The manufacturing method of the multilayer electronic component according to claim 4, wherein the solidification drying process is performed in a reduced pressure atmosphere.   The method for manufacturing a multilayer electronic component according to claim 1, wherein the solidification drying process is performed while applying pressure.   The stacked electron according to any one of claims 1 to 7, wherein the green chip is subjected to a binder removal process so that a residual carbon amount in the green chip is 0.1 to 0.4 wt% in the binder removal process. A manufacturing method for parts.   The binder removal treatment is performed at a heating rate S2: 1 to 15 ° C./hour (excluding 1 ° C./hour), a holding temperature T2: 400 to 800 ° C., and a holding time t2 of the holding temperature T2: 1 to 8 hours. The manufacturing method of the multilayer electronic component according to any one of claims 1 to 8, which is performed under conditions.   The method for manufacturing a multilayer electronic component according to claim 1, wherein a ceramic green sheet having a thickness of 3 μm or less is used.

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