JP2969673B2 - Manufacturing method of multilayer ceramic electronic component - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer ceramic electronic component such as a multilayer ceramic capacitor widely used for electric products such as a video tape recorder and a liquid crystal television. In addition, the present invention can be widely used when manufacturing multilayer ceramic electronic components such as a multilayer ceramic substrate, a multilayer varistor, and a multilayer piezoelectric element.

2. Description of the Related Art In recent years, in the field of electronic components, with the increase in the density of circuit components, there has been a demand for increasingly smaller and higher performance multilayer ceramic capacitors and the like.

FIG. 3 is a diagram showing a cross section of a part of the multilayer ceramic capacitor. In FIG. 3, 1 is a ceramic dielectric layer, 2 is an internal electrode, and 3 is an external electrode. The internal electrodes 2 are each connected to the external electrodes 3.

Conventionally, a multilayer ceramic capacitor has been manufactured by the following manufacturing method.

First, a predetermined electrode ink is printed on a ceramic raw sheet cut to a predetermined size, and the electrode ink is dried to form an electrode ink film. The required number of ceramic raw sheets on which the electrode ink film is formed is formed. Lamination was performed to obtain a ceramic green laminate, and this ceramic green laminate was cut into a desired shape, fired, and external electrodes were attached to complete the ceramic green laminate.

However, in the method of printing the electrode ink directly on such a ceramic green sheet, as the number of laminated ceramic green sheets on which the electrode ink film is formed increases, irregularities due to the thickness of the electrode ink film are formed. It will appear on the surface of the ceramic green laminate. Then, due to the unevenness generated on the surface of the ceramic green laminate, as the number of layers increases, lamination failure due to uneven distribution of lamination pressure or firing failure due to partial density difference of the ceramic green laminate. However, there is a problem that such a problem easily occurs.

Conventionally, as an approach to such a problem, a ceramic raw sheet in which a portion corresponding to an electrode portion as proposed in JP-A-53-42353 is missing (or punched) at least partially in the thickness direction is used. There is a method, and Japanese Patent Application Laid-Open No. 52-133553 proposes to use a ceramic raw sheet in which a portion corresponding to an electrode is a void. Further, Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open No. 135051 discloses that ceramic ink is printed on the unprinted portion (remaining portion) of the electrode of the ceramic green sheet on which the electrode ink is printed.
Japanese Patent Application Laid-Open No. 52-135050 proposes to insert a ceramic raw sheet from which a portion corresponding to an electrode has been removed.

However, all of these methods are directly processed or printed on a raw ceramic sheet having poor mechanical strength,
There was a problem that the implementation became more difficult as the thickness of the ceramic green sheet decreased. In particular, a ceramic raw sheet having a size of about 20 μm or less is difficult to handle by itself (fragile), difficult to laminate itself, and it is extremely difficult to perform mechanical processing or printing with high precision. The cost was high.

SUMMARY OF THE INVENTION In such a method for manufacturing a multilayer ceramic electronic component, as the number of laminated ceramic green sheets on which an electrode ink film is formed increases, the electrode ink film is formed on the surface of the completed ceramic green laminate. Unevenness caused by the above. Due to the generated irregularities, partial pressure unevenness occurs when laminating the ceramic green sheet on which the electrode ink film is formed, and a failure occurs when laminating or firing the completed ceramic green laminate. Had problems.

In view of the above problems, an object of the present invention is to propose a manufacturing method capable of preventing the occurrence of irregularities due to electrodes on the surface of a ceramic green laminate even when the number of laminates is increased.

Means for Solving the Problems In order to solve the above-mentioned problems, a method for manufacturing a multilayer ceramic electronic component of the present invention is characterized in that each time a predetermined number of laminated ceramic green laminates are formed, a dent formed on a surface thereof is fitted. The convex ceramic ink film formed on the surface of the support as described above, without peeling from the support, after thermocompression bonding to the surface of the ceramic green laminate, peeling only the support, And transferring the ceramic ink film to the surface of the ceramic green laminate.

Operation According to the present invention, with the above-described configuration, irregularities generated on the surface of the ceramic green laminate can be filled. In addition, since the ceramic ink film can be handled together with the support, even a ceramic ink film printed in a predetermined pattern with a small mechanical strength is easy to handle during operation. Further, the alignment at the time of lamination is performed using a support having excellent mechanical strength and dimensional accuracy, instead of the raw ceramic sheet, so that the lamination accuracy can be improved.

In addition, the printing pattern of the ceramic ink film is not a ceramic raw sheet having poor mechanical strength, but can be printed directly on the support, so that printing can be performed with high accuracy. Further, the solvent contained in the ceramic ink does not permeate the support. Also, the degree of drying of the ceramic ink can be easily controlled.

EXAMPLES Hereinafter, a method for manufacturing a multilayer ceramic capacitor and a method for laminating the same according to one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 illustrates a method for flattening a ceramic green laminate according to the present invention. In FIG.
Reference numeral 4 denotes a base, reference numerals 5 and 5a denote supports, reference numeral 6 denotes a ceramic green laminate, reference numeral 7 denotes an electrode ink film, and reference numeral 8 denotes a depression. This depression 8 is a portion of the ceramic raw laminate 6 where the electrode ink film 7 is not laminated. Has occurred. The depression 8 is formed by the thickness of the electrode ink film 7 when the green ceramic sheet on which the electrode ink film 7 is formed is laminated, and is formed by the thickness of the electrode ink film 7 or the ceramic on which the electrode ink film 7 is formed. It tends to increase depending on the number of stacked raw sheets. 9 is a ceramic ink film, 10 is a hot plate, and 11 is a heater. The heater 11 functions to maintain the hot plate 10 at a constant temperature.
Arrows indicate the direction in which the hot platen 10 moves. Here, the hot platen 10 moves in the direction of the arrow, and the ceramic ink film 9 formed on the support 5a is pressed onto the depression 8 on the surface of the ceramic green laminate 6 so as to fill the depression 8. Will be.

Next, a more detailed description will be given with reference to FIG. FIG. 2 is a view for explaining how the ceramic green laminate according to the present invention is flattened. The arrow points to the hot plate 10
It indicates the direction in which the object moves. As shown in FIG.
The surface of the ceramic green laminate 6 is flattened by transferring the ceramic ink film 9 shown in FIG. 1 to the dents (the dents 8 shown in FIG. 1) formed on the surface of the ceramic green laminate 6. can do. In the ceramic green laminate 6 thus flattened, ceramic green sheets on which the electrode ink films are formed can be continuously laminated, and the number of laminated ceramic green sheets can be further increased. As described above, the present invention can be used when unevenness due to the electrode ink film occurs on the surface of the ceramic green laminate regardless of the number of layers, and the number of layers can be further increased. Further, in the method for manufacturing a ceramic electronic component of the present invention, the transfer of the ceramic ink film is not performed every time the lamination is performed, that is, the transfer can be performed as needed, so that the lamination cost does not increase.

Next, a more detailed description will be given. First, as an electrode ink for forming an electrode ink film, a solvent was added to a commercially available electrode ink (Pd paste for an internal electrode of a multilayer capacitor) and adjusted to have an appropriate viscosity and drying speed (hereinafter, simply referred to as a simple drying method). To the electrode ink).

Next, how to make a ceramic slurry will be described. First, a thermoplastic resin containing a polyvinyl butyral resin is added to a solvent and a plasticizer, and after sufficiently dissolving, a ceramic powder mainly composed of barium titanate having a particle size of about 1 micron is dispersed using a ball mill. After filtering using a predetermined filter to obtain a ceramic slurry, by applying on a support film using a doctor blade, by drying the ceramic slurry,
A green ceramic sheet was produced on the support. Here, when the thickness of the ceramic green sheet was measured, it was about 15 μm. Next, an electrode ink was printed on the ceramic green sheet (as it was formed on the support), and the electrode ink was dried to form an electrode ink film on the ceramic green sheet. The ceramic green sheet on which the electrode ink film was formed was laminated on a ceramic green sheet having a thickness of 200 μm by using an ordinary method so that 40 layers of the electrode ink film were alternately displaced to produce a ceramic green laminate. .
Here, when the unevenness caused by the electrode ink film laminated on the surface of the ceramic green laminate was measured using a surface roughness meter, the depth of the depression (corresponding to the depression 8 in FIG. 1) was 20 to 30
μm (hereinafter, simply referred to as a ceramic green laminate having irregularities).

Next, how to make a ceramic ink will be described.
First, ceramic ink is prepared by dissolving a thermoplastic resin having the same composition as the ceramic slurry in a solvent for screen printing, and adding the ceramic powder mainly composed of barium titanate to a vehicle (resin solution) produced. And
The mixture was dispersed using a three-roll mill to obtain a ceramic ink. This ceramic ink was printed on a support film in a predetermined shape using a screen printing method, and the ceramic ink was dried to form a ceramic ink film on the support (hereinafter simply referred to as a transfer film). Call). Here, the thickness of the ceramic ink film could be adjusted to 20 to 30 μm by adjusting the type of screen plate used for screen printing and the thickness of the emulsion.

Next, on the ceramic green laminate having the irregularities,
As shown in FIGS. 1 and 2, when the ceramic ink film was transferred from the transfer film, the unevenness of the surface of the ceramic green laminate was 20 to 30 μm, and the unevenness was 0 to 3 μm.
The degree could be greatly reduced.

Further, on this, after laminating 40 layers of the ceramic raw sheet on which the electrode ink film was formed, the ceramic ink film was further transferred from the transfer film, and 40 layers of the ceramic raw sheet on which the electrode ink film was formed were further laminated, By transferring the ceramic ink film, a total of 120 electrode ink films can be obtained.
A laminated ceramic green body having a flat surface was obtained. Next, a green ceramic sheet having a thickness of 200 μm is laminated thereon, and cut into a predetermined shape.
By baking and attaching external electrodes, a multilayer ceramic capacitor could be manufactured.

Next, as a conventional example, an attempt was made to mechanically punch out the portion corresponding to the electrode ink film from the ceramic raw sheet of about 15 μm. First, when the raw ceramic sheet was peeled off from the surface of the support, the strength of the raw ceramic sheet itself was sharply reduced, so that the raw ceramic sheet was hardly handled and could not be punched. Next, while the ceramic raw sheet was formed on the surface of the support, an attempt was made to mechanically punch the ceramic raw sheet. However, the ceramic raw sheet alone could not be punched without damaging the surface of the support. In addition, although the ceramic raw sheet could be cut out by damaging the surface of the support, unnecessary ceramic raw sheet portions could not be peeled off.
Furthermore, although we tried to punch the ceramic raw sheet together with the support, burrs were generated by punching the support, and the support was irregularly distorted due to the decrease in the mechanical strength of the support itself, and accurate lamination was possible. Did not. As described above, the conventional method cannot effectively fill (flatten) the recesses of the ceramic green laminate having the irregularities.

In the present invention, when the ceramic ink film is transferred from the transfer film, the transfer may be performed using light, an electron beam, microwave, X-ray, or the like, in addition to heat.
Also, by changing the type of the resin used, the type and the amount of the plasticizer to be added, the storage stability, the decrease in the transfer temperature (room temperature),
High-speed lamination is also possible.

In addition, as ceramics, insulators, dielectrics, conductors,
Various materials such as semiconductors and magnetic materials can be used.

Further, the manufacturing method of the present invention can be applied not only to the multilayer ceramic capacitor described in the above embodiment but also to other multilayer ceramic electronic components such as a multilayer ceramic substrate and a multilayer varistor.

Effect of the Invention As described above, according to the present invention, every time a predetermined number of laminated ceramic green laminates are formed, the dents generated on the surface can be flattened by a very simple method and reliably. Thus, the number of layers can be further increased, and a multilayer ceramic electronic component can be manufactured with good yield.

[Brief description of the drawings]

FIG. 1 is a view for explaining a method of flattening a ceramic green laminate in the present invention, FIG. 2 is a view for explaining a flattened state of a ceramic green laminate in the present invention,
FIG. 3 is a perspective view showing a cross section of a part of the multilayer ceramic capacitor. 4 ... table, 5,5a ... support, 6 ... ceramic green laminate, 7 ... electrode ink film, 8 ... dent, 9 ... ceramic ink film, 10 ... hot platen, 11 ... heater .

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-65829 (JP, A) JP-A-64-51610 (JP, A) JP-A-64-42809 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) H01G 4/12 364

Claims (1)

(57) [Claims] Each time the electrode ink film and the ceramic green sheet are laminated to form a predetermined number of laminated ceramic green laminates, the ceramic green sheets are formed on the surface of the support so as to fit into the depressions formed on the surface. The convex ceramic ink film is thermally peeled off to the surface of the ceramic green laminate without peeling from the support, and only the support is peeled off, and the ceramic ink film is peeled off from the ceramic green laminate. A method for producing a multilayer ceramic electronic component, comprising: