JP2950008B2 - Manufacturing method of multilayer ceramic electronic component - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer ceramic capacitor, a multilayer printed wiring board, a multilayer varistor, a multilayer piezoelectric element,
The present invention relates to a method for manufacturing a multilayer ceramic electronic component such as a multilayer chip inductor. More specifically, the present invention relates to a method for manufacturing a laminated ceramic electronic component by laminating and pressing a plurality of ceramic green sheets each having an electrode formed by printing.

[0002]

2. Description of the Related Art Conventionally, as a method of integrating a laminated green body obtained by laminating a plurality of ceramic green sheets of this kind, a laminated green body having an electrode layer formed therein is placed in a lower mold of a mold, and the upper surface thereof is placed in a lower mold. There is known a mechanical pressing method in which each green sheet constituting a laminated green body and an internal electrode layer are pressure-bonded without gaps by pressing a mold. However, this mechanical pressing method is complicated and inefficient, and the sheet thickness of the electrode forming portion of the ceramic green sheet is larger than that of the portion where no electrode is formed. Pressure is not uniformly applied to the body, and pressure distortion is likely to occur in the laminated green body. When this laminated green body is fired, it tends to cause delamination (layer peeling) and cracks inside. Further, it is difficult to accurately maintain the parallelism and position of the upper and lower dies with a mechanical press, and when the green sheet is thin, delamination and the like are more likely to occur due to pressure distortion.

To solve these problems, a method of vacuum-packing a laminated green body with a flexible sheet and then isostatically pressing the vacuum-packed laminated green body (Japanese Patent Publication No. 3-585)
24) Alternatively, the laminated green body held in the frame is vacuum-packaged with the flexible sheet together with the frame, and the vacuum-packed laminated green body with the frame is subjected to hydrostatic pressure pressing, followed by isostatic pressing, and then taking out the laminated green body ( Japanese Patent Publication No. 3-58525) has been proposed.

[0004]

However, in the former hydrostatic pressing method, since the entire laminated green body contracts uniformly, the direction other than the thickness direction of the laminated body also contracts. For this reason, the side portions of the laminated green body after pressing become irregular, and the position of the electrode printed on the green sheet tends to fluctuate after pressing, and it is difficult to cut the laminated green body accurately according to the electrode. . In the latter isostatic pressing method, since the laminated green body is put into the frame and then isostatically pressed, the above problem is improved, but the framing and framing work of the laminated green body is complicated and the number of manufacturing steps increases. There was a defect.

An object of the present invention is to provide a method of manufacturing a laminated ceramic electronic component which does not cause defects such as delamination and cracks after firing by firing a laminated green body uniformly. Another object of the present invention is to provide a method for manufacturing a laminated ceramic electronic component which can be cut at a predetermined position with high precision without dimensional irregularities and electrode positions after pressing of a laminated green body, and with a small number of steps. It is in.

[0006]

In order to achieve the above-mentioned object, a manufacturing method of the present invention comprises, as shown in FIG. 1 to FIG. A temporary bonding step of temporarily bonding the body 12, a packaging step of vacuum packaging the laminated green body 12 temporarily bonded to the carrier plate 10 together with the carrier plate 10, and statically bonding the vacuum-packaged laminated green body 12 with the carrier plate. The pressing step of hydraulic pressing, and when the longitudinal direction and the lateral direction of the carrier plate 10 are set to the x direction and the y direction, respectively, the laminated green body 12 with the carrier plate that has been subjected to the hydrostatic pressing is retained in the x direction and the y direction while leaving the carrier plate 10. And a peeling step of peeling the cut laminated green body 12 from the carrier plate 10.

(A) fixing a ceramic green sheet on the surface of the rigid carrier plate 10 by hot pressing, printing a conductive paste for an electrode layer, and drying the laminated green body 12; After another ceramic green sheet is overlaid on the green sheet and fixed by hot pressing, a step of printing and drying a conductive paste for an electrode layer is performed, and then the step (b) is repeated. Is preferred. In the temporary bonding step, a base film 14 with an adhesive is attached to the surface of the rigid carrier plate 10 with the adhesive 13, and the resin layer 1 is attached to the surface of the film 14.
After forming 6, the laminated green body 12 is preferably temporarily bonded to the resin layer. Further, it is preferable that the peeling from the rigid carrier plate 10 in the peeling step is performed by peeling the base film 14 from the rigid carrier plate 10. Further, it is preferable to include a printing step of printing a cut mark 17 on the upper surface of the laminated green body 12 between the temporary bonding step and the packaging step, and to cut the laminated green body 12 by the cut mark 17 in the cutting step.

[0008]

By wrapping the laminated green body in a flexible bag and vacuum-packing, it is possible to remove a small amount of gas or the like remaining in the laminated green body and to further densify the inside of the laminated green body. In addition, since the laminated green body together with the rigid carrier plate is subjected to isostatic pressing, pressure is first applied uniformly to the electrode forming part and the non-electrode forming part of the laminated green body so that pressure distortion does not occur, and delamination and cracking occur after firing. No defects such as Secondly, since the laminated green body is held on the rigid carrier plate at the time of pressurization, the dimensional variation of the laminated green body in the horizontal direction perpendicular to the laminating direction is almost eliminated, the dimensions are not irregular after pressing, and the electrode position is reduced. Does not fluctuate. Also, if the isostatic pressing is performed using the working fluid having the increased temperature, the binder contained in each of the ceramic green sheet and the conductive paste is pressurized in a softened state, so that a product that is more closely adhered to at a relatively low pressure can be obtained. Furthermore, if a cut mark is provided on the uppermost surface of the laminated green body, the laminated green body after the isostatic pressing can be extremely easily and accurately cut.

[0009]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. In this example, a multilayer ceramic capacitor will be described as a representative. <Temporary bonding step> As shown in FIG.
Green body 12 having electrode layer 11 inside on the surface of
Are temporarily bonded. More specifically, a base film 14 made of polyethylene terephthalate having a thickness of about 250 μm and having an adhesive 13
Affix to the surface of No. The adhesive 13 is a base film 14
Is selected to have an adhesive strength enough to be peeled off from the carrier plate when it is lightly pulled up by hand. This film 14
Is coated with ethylcellulose to form a thin resin layer 1
6 are formed. This resin layer 16 is formed on the laminated green body 12.
When the ceramic green sheet constituting the above is hot pressed, it exhibits an adhesive force. The resin layer 16 is not limited to ethyl cellulose, and may be any material having the same adhesive effect. In this example, the carrier plate 10 is an aluminum plate whose surface is anodized. The material is not limited to aluminum and may be, for example, stainless steel as long as the material does not cause deformation, shrinkage, and the like at high temperature and high pressure.

The laminated green body 12 is a rigid carrier plate 10.
It is made by fixing a plurality of ceramic green sheets one by one on a film 14 on the surface of the substrate by hot pressing. In this example, the green sheet is formed by film-forming and drying a dielectric slurry having a JIS-R characteristic of barium titanate containing polyvinyl butyral or an acrylic binder and a plasticizer by a doctor blade method. After a predetermined number of green sheets are laminated on the internal electrode layer 11,
It is formed by printing and drying a conductive paste for an electrode layer on the upper surface. Thereafter, lamination of a predetermined number of green sheets on which no electrode layer is formed and formation of the electrode layer are repeated. In this example, the conductive paste is prepared by mixing Pd powder with a vehicle containing ethyl cellulose as a main component. Ag / Pd, Ni, Cu or the like may be used instead of Pd. As shown in detail in FIG.
Is formed, a cut mark 17 is provided on the surface of the uppermost green sheet, that is, on the upper surface of the laminated green body 12.
The cut mark 17 is provided by using a mask for forming the internal electrode layer as it is, replacing the ink for the cut mark, and printing and drying.

<Packaging Step> As shown in FIG. 3A, the laminated green body 12 temporarily bonded in the temporary bonding step is vacuum-packaged in a flexible bag 18 together with the carrier plate 10. In this example, the bag 18 is made of nylon. The material is not limited to nylon as long as it can be sealed by vacuum decompression, and may be rubber or other plastic materials. It is preferable to seal in a vacuum in order to remove the residual solvent gas in the laminated green body.

<Pressing Step> As shown in FIG. 4, a plurality of vacuum-packaged laminated green bodies 12 with a carrier plate are accommodated in a tray 21 and a working fluid 22 of a pressing machine 20 is used.
Put in. Here, the laminated green body 12 is isostatically pressed by applying a pressure of 300 kg / cm ² . Thereby, a plurality of laminated green bodies 12 are subjected to a pressure treatment at once. Silicone oil or water is used as the working fluid 22. The working fluid is 6 to increase the crimping effect.
Preferably, the temperature is raised to about 5 ° C. The temperature of the working fluid is raised by intermittently injecting the working fluid stored in a heating tank (not shown) from the heating tank.

<Cutting Step> As shown in FIG. 3 (b), the laminated green body 12 with the carrier plate which has been isostatically pressed is taken out by opening the flexible bag 18. This is set on a cutting machine table (not shown). Here, when the vertical direction and the horizontal direction of the carrier plate 10 are the x direction and the y direction, respectively,
Using the cut marks 17 on the surface of the laminated green body as a guide, the laminated green body 12 with a carrier plate is cut in the x and y directions while leaving the carrier plate 10. Specifically, the blade (not shown) of the cutting machine is stopped when it reaches the inside of the base film 14 as shown by the broken line in FIG. Since the laminated green body 12 with the carrier plate after pressing does not contract in the horizontal direction, the cutting can be performed by an automatic cutting machine, and in this case, the production efficiency is extremely high. <Peeling Step> After cutting the laminated green body 12, when the base film 14 is peeled from the carrier plate 10, the film 14 is curved, and at the same time, the laminated green body 12 cut into a chip is easily peeled off from the film 14. I do.
The remaining carrier plate 10 is repeatedly used for temporary bonding of the next laminated green body.

<Firing step> The chip-shaped laminated green body is subjected to a binder removal treatment, and then is heated to 1300 ° C. under atmospheric pressure.
For 2 hours to obtain a chip-type multilayer ceramic capacitor body. An appearance inspection and an internal analysis of each of the 20 chip-type multilayer ceramic capacitor bodies were performed. As a result, there was no variation in dimensions, and none of them had defects such as delamination and cracks.

In the embodiment, as the dielectric slurry,
Although a barium titanate-based material having JIS-R characteristics has been described, other dielectric slurry such as a lead-based material may be used. The material of the base sheet 14 is not limited to polyethylene terephthalate, but may be another plastic sheet. Furthermore, although the multilayer ceramic capacitor has been described, the present invention is not limited to this, and can be applied to the manufacture of multilayer ceramic electronic components such as multilayer printed wiring boards, multilayer varistors, multilayer piezoelectric elements, multilayer chip inductors and the like.

[0016]

As described above, since the present invention is based on the hydrostatic pressing method, a uniform pressure is applied to the laminated green body, and defects such as delamination cracks after firing which have been generated by the conventional mechanical pressing method are generated. Disappears. Also, compared to the conventional hydrostatic pressing method, the laminated green body is held by the rigid carrier plate, and the lateral shrinkage of the laminated green body is extremely small. Cutting errors based on layers are almost eliminated. Furthermore, it is possible to apply a hydrostatic press without entering / exiting a special frame, and to pressurize a large number of laminated green bodies in a lump. Moreover, it is easy to cut the laminated green bodies after pressing. A multilayer ceramic electronic component can be manufactured well.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along the line AA of FIG. 2, showing a state in which a laminated green body according to an embodiment of the present invention is temporarily bonded to a surface of a rigid carrier plate.

FIG. 2 is a plan view of FIG. 1;

FIG. 3A is a cross-sectional view showing a state in which a laminated green body with a carrier plate is vacuum-packaged in a flexible bag. (B) is sectional drawing corresponding to FIG. 1 of the laminated green body with a carrier plate pressed by the hydrostatic pressure.

FIG. 4 is a sectional view of a main part of a hydrostatic press for the laminated green body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rigid carrier plate 11 Electrode layer 12 Laminated green body 13 Adhesive 14 Base film 16 Resin layer 17 Cut mark 18 Flexible bag 20 Hydrostatic press machine 21 Tray 22 Working fluid

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-2-58816 (JP, A) JP-A-1-210309 (JP, A) JP-A-2-208912 (JP, A) JP-A-4- 8498 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) H01G 4/12

Claims (5)

(57) [Claims] 1. A temporary bonding step of temporarily bonding a laminated green body (12) having an electrode layer (11) inside to a surface of a rigid carrier plate (10), and a laminate temporarily bonded to the carrier plate (10). Green body (12)
A packaging step of vacuum packaging with the carrier plate (10), and a laminated green body with the vacuum-packed carrier plate (12).
A press step of isostatic pressing, and when the longitudinal direction and the lateral direction of the carrier plate (10) are set to the x direction and the y direction, respectively, the laminated green body (12) with the carrier plate subjected to the isostatic pressing is applied to a carrier plate ( A method for producing a multilayer ceramic electronic component, comprising: a cutting step of cutting in the x and y directions while leaving 10); and a peeling step of peeling off the cut laminated green body (12) from the carrier plate (10). 2. A laminated green body (12) comprising: (a) fixing a ceramic green sheet on the surface of a rigid carrier plate (10) by hot pressing, and then printing and drying a conductive paste for an electrode layer; And (b) laminating another ceramic green sheet on the green sheet and fixing by hot pressing, then printing and drying a conductive paste for an electrode layer, the step (b) The method for producing a multilayer ceramic electronic component according to claim 1, wherein the method is repeated. In the temporary bonding step, a base film with an adhesive is adhered to the surface of the rigid carrier plate with the adhesive, and a resin layer is formed on the surface of the film. 2.) The method of manufacturing a multilayer ceramic electronic component according to claim 1, wherein, after forming (a), a laminated green body (12) is temporarily bonded onto the resin layer. 4. The peeling of the base film (14) from the rigid carrier plate (10) in the peeling step is performed.
4. The method for manufacturing a multilayer ceramic electronic component according to claim 3, wherein the method is performed by peeling off the laminate. 5. A printing step of printing a cut mark (17) on the upper surface of the laminated green body (12) between the temporary bonding step and the packaging step, and the cutting step includes the step of printing the laminated green body by the cut mark (17). 2. The method according to claim 1, wherein (12) is cut.