JP2969672B2 - 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. 4 is a diagram showing a cross section of a part of the multilayer ceramic capacitor. In FIG. 4, 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 having a portion corresponding to an electrode portion missing (or punched) at least partially in the thickness direction as proposed in JP-A-53-42353 has been proposed. There are methods to use. Also, in JP-A-52-133553,
It has been proposed to use a ceramic raw sheet in which a portion corresponding to the electrode is a void. In addition, JP
JP-A-135051 discloses that ceramic ink is printed on the non-printed 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, extremely difficult to machine or print with high accuracy, and high cost. It was something that would be.

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 layers is increased.

Means for Solving the Problems In order to solve the above problems, a method for manufacturing a multilayer ceramic electronic component according to the present invention is characterized in that each time a predetermined number of laminated ceramic green laminates are formed, Uneven ceramic raw sheet having irregularities formed on 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, The uneven ceramic raw sheet is transferred onto the surface of the ceramic green laminate.

Effect of the Invention According to the present invention, since the ceramic ink film is formed on the ceramic green sheet and can be handled together with the support with the above-described configuration, the handling during the operation is facilitated. In addition, the positioning at the time of lamination is performed using a support having excellent mechanical strength and dimensional accuracy, instead of the raw ceramic sheet, and the lamination accuracy can be improved.

In particular, for a ceramic green laminate having an uneven surface due to a multilayered electrode ink film, the unevenness of the ceramic green laminate surface is reduced by utilizing the unevenness of the ceramic green sheet surface. And the number of stacked layers can be further increased.

EXAMPLES Hereinafter, a method of manufacturing a multilayer ceramic capacitor and a method of laminating the same as a first 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. Here, the ceramic raw sheet having irregularities on the surface formed on the support is manufactured by printing a ceramic ink film in a predetermined shape on the surface of the ceramic raw sheet formed on the support. Used. In FIG. 1, 4 is a base, 5, 5a are supports, 6 is a ceramic green laminate, 7 is an electrode ink film,
Reference numeral 8 denotes a depression, which is formed in a portion of the ceramic green laminate 6 where the electrode ink film 7 is not laminated.
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 raw sheet, 10 is a ceramic ink film provided at a pitch equal to the pitch of the electrode ink film 7, 11 is a hot plate, 12 is a heater, and the heater 12 keeps the hot plate 11 at a constant temperature. Work. Arrows indicate the direction in which the hot platen 11 moves. Here, the hot platen 11 moves in the direction of the arrow,
The ceramic raw sheet 9 and the ceramic ink film 10 formed on 5a are pressed onto the depression 8 on the surface of the ceramic green laminate 6 so as to fill the depression 8.

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. As shown in FIG. 2, the ceramic green sheet 9 and the ceramic ink film 10 shown in FIG. 1 are transferred to the dent (the dent 8 shown in FIG. 1) formed on the surface of the ceramic green laminate 6. Thereby, the surface of the ceramic green laminate 6 can be flattened. The ceramic green laminate 6 thus flattened
Can successively laminate the ceramic raw sheet on which the electrode ink film is formed, and can further increase the number of laminates. 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 for each lamination, that is, may 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 due to the electrode ink film formed 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 is printed in a predetermined shape on a ceramic green sheet formed on a support film using a screen printing method, and the ceramic ink is dried to form a ceramic ink film on the surface of the ceramic green sheet on the support. (Hereinafter simply referred to as a transfer film). 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 green sheet and the ceramic ink film were transferred from the transfer film, the surface unevenness of the ceramic green laminate was 20 to 30.
μm was significantly reduced to about 0 to 3 μm. Also, on this, after laminating 40 layers of the ceramic raw sheet on which the electrode ink film was formed, and further from the transfer film,
Transfer ceramic raw sheet and ceramic ink film,
In addition, a ceramic raw sheet with an electrode ink film
By laminating 40 layers and transferring the ceramic raw sheet and the ceramic ink film, a ceramic green laminate having a flat surface and a total of 120 electrode ink films laminated could be manufactured. Next, a green ceramic sheet having a thickness of 200 μm was laminated thereon, cut into a predetermined shape, fired at 1300 ° C., and external electrodes were attached, whereby a multilayer ceramic capacitor was manufactured.

Next, as a conventional example, an attempt was made to mechanically punch out a 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. Also, by damaging the surface of the support,
Although the ceramic raw sheet could be cut out, unnecessary ceramic raw sheet portions could not be peeled off. Furthermore, we tried to punch the ceramic raw sheet for each support, but burrs were generated by punching the support,
In addition, the support was irregularly distorted due to a decrease in the mechanical strength of the support itself, so that accurate lamination could not be performed. As described above, the conventional method cannot effectively fill (flatten) the recesses of the ceramic green laminate having the irregularities.

Next, as a second embodiment, after printing a ceramic ink film in a predetermined shape on a support, a ceramic raw sheet manufactured by forming a ceramic raw sheet thereon is used. Similarly, the ceramic green laminate was flattened.

FIG. 3 is a second view of the ceramic green laminate of the present invention.
For explaining the flattening method. 3, the difference from FIG. 1 is that the ceramic ink film 10a is formed between the support 5b and the ceramic green sheet 9a.

Here, the only difference between the first embodiment and the second embodiment is that the printing procedure of the ceramic ink and the procedure for preparing the ceramic raw sheet with the doctor blade are different. By using the thus-prepared raw ceramic sheet having irregularities on the surface and manufacturing it in the same manner as shown in FIGS. 1 and 2, the ceramic sheet having irregularities on the surface as in the first embodiment is obtained. The surface of the green laminate could be flattened.

In particular, in the present invention, by transferring a ceramic raw sheet having irregularities on the surface in a state formed on the support, lamination accuracy is also improved, and the releasability of the ceramic raw sheet having irregularities on the surface from the support is also improved. Can be stabilized.

In the present invention, when the ceramic raw sheet and the ceramic ink film are 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. Further, by changing the type of the resin used, the type and the amount of the plasticizer to be used, storage stability, a reduction in the transfer temperature (room temperature), and an increase in the speed of lamination are 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.

Advantageous Effects of the Invention As described above, according to the present invention, every time a predetermined number of laminated ceramic green laminates are formed, the unevenness generated on the surface can be flattened with a very simple method and reliably. 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 view for explaining a second flattening method of the ceramic green laminate according to the present invention, and FIG. 4 is a perspective view showing a cross section of a part of the multilayer ceramic capacitor. 4 ... table, 5,5a, 5b ... support, 6 ... ceramic green laminate, 7 ... electrode ink film, 8 ... dent, 9,9a ... ceramic raw sheet, 10,10a ... ceramic Ink film, 11…
... Heat plate, 12 ... Heater.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-188926 (JP, A) JP-A-64-42807 (JP, A) JP-A-1-208824 (JP, A) JP-A 52-188 135051 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01G 4/12 364

Claims (3)

(57) [Claims] Each time an electrode ink film and a ceramic green sheet are laminated to form a predetermined number of laminated ceramic green laminates, a ceramic green laminate is formed on a support that fits with irregularities generated on the surface thereof. The irregular ceramic raw sheet having irregularities on its surface is not peeled off from the support, and after being thermocompression-bonded to the surface of the ceramic laminate, only the support is peeled off, and the irregular ceramic raw sheet is removed from the ceramic. A method for producing a multilayer ceramic electronic component, which comprises transferring the pattern to a surface of a green laminate. 2. The multilayer ceramic electronic device according to claim 1, wherein the uneven ceramic green sheet is manufactured by printing a ceramic ink film in a predetermined shape on the surface of the ceramic green sheet formed on the support. The method of manufacturing the part. 3. The ceramic sheet with irregularities produced by covering a ceramic ink film printed in a predetermined shape on a support with a ceramic sheet.
A method for manufacturing the multilayer ceramic electronic component according to the above.