JP2996049B2 - 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 method for manufacturing a multilayer ceramic electronic component such as a multilayer capacitor, and more particularly to a process for obtaining a multilayer chip for each multilayer ceramic electronic component from an unfired mother laminate. The present invention relates to a method for manufacturing a multilayer ceramic electronic component having improved characteristics.

[0002]

2. Description of the Related Art When manufacturing a multilayer ceramic electronic component, a mother laminate is usually prepared, and the mother laminate is cut into individual multilayer ceramic electronic component units and fired in order to enhance mass productivity. Is used.

For example, taking a method of manufacturing a multilayer capacitor as an example, first, an unfired mother laminate in which a number of internal electrodes are buried side by side is obtained. Thereafter, the mother laminate is cut, and the mother laminate is cut into laminate chips of individual multilayer capacitor units.

FIG. 1 shows an example of a laminated chip obtained as described above. In the multilayer chip 1, the internal electrodes 3 and 5 are arranged in the multilayer body 2 so as to overlap with each other in the thickness direction while being separated by an unfired ceramic layer.

[0005] The laminated chip 1 obtained as described above
Is usually separated by applying a vibration to prevent bonding of the stacked chips, and then fired. After firing, by forming external electrodes and the like, a final multilayer capacitor is obtained.

[0006]

As described above, in the conventional method for manufacturing a multilayer ceramic electronic component, prior to firing, the mother laminate is cut into individual ceramic electronic component-unit laminate chips, and a large number of laminate chips are cut. A body chip has been obtained. However, the ceramic portion of the laminated chip contains a synthetic resin binder and a solvent in addition to the ceramic powder. Therefore, there is a problem in that when the adjacent stacked chips come into contact with each other after being cut, they tend to be coalesced by the binder and the solvent. The bonding of the laminated chips is prevented to some extent by performing the above-described separation step by applying vibration.

However, even if vibration is applied to prevent the bonding of the stacked chips, if the stacked chips come into contact again after the separation step and are fired in that state, a plurality of stacked chips will still be formed. Thus, a sintered chip in which the laminated chips of the above are integrated is obtained.

[0008] As described above, the sintered body obtained as a result of the bonding of the adjacent laminated chips is forcibly divided even if it is subsequently separated, so that the sintered body having the desired shape is sintered. You can't get your body. That is, chips and cracks tend to occur in the finally obtained sintered body chip.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer ceramic which can effectively prevent the bonding of individual multilayer chips and thereby suppress the occurrence of cracks and chips in the finally obtained sintered chip. An object of the present invention is to provide a method for manufacturing an electronic component.

[0010]

The present invention SUMMARY OF THE INVENTION includes the steps of preparing an unfired mother ceramic laminate in which a plurality of internal electrodes are embedded in parallel, the ceramic laminate of the mother
Pressing the body in the thickness direction, a pretreatment step of leaving the pressurized mother ceramic laminate under reduced pressure, and after the pretreatment step, the mother ceramic laminate is separated into individual ceramic electronic component units. And a step of firing the ceramic laminated chip obtained by the cutting. A method of manufacturing a laminated ceramic electronic component, comprising:

In the present invention, the step of preparing the mother ceramic laminate includes, for example, laminating a plurality of ceramic green sheets on which a conductive paste for forming a plurality of internal electrodes is printed, and vertically This is performed by laminating a plurality of ceramic green sheets on which no internal electrodes are printed and pressing them in the thickness direction.
Alternatively, on a supporting substrate such as a synthetic resin film,
The step of printing and drying the ceramic powder-containing paste and then the step of printing and drying the conductive paste may be appropriately repeated.

The pretreatment step in the present invention is carried out by leaving the mother ceramic laminate obtained as described above under reduced pressure. 30-2
It is performed by leaving it for 40 minutes. However, since the degree of pressure reduction and the standing time vary depending on the size and material composition of the mother ceramic laminate used, they cannot be uniquely determined. However, when the degree of pressure reduction is large (that is, when the pressure is too low) and when the standing time is too long, the surface of the mother ceramic laminate is too dry, which is not preferable. In addition, when the degree of decompression is small (when the pressure is too high) or when the standing time is too short, the solvent and water are not sufficiently scattered from the surface of the mother ceramic laminate, so that the chip between the laminate chips is not formed. Coalescence cannot be effectively prevented. The degree of pressure reduction and the standing time are determined according to the individual mother laminates from the above viewpoint. The steps after the pretreatment step, that is, the steps of cutting the mother ceramic laminate into individual ceramic laminate chips and firing the individual ceramic laminate chips, etc., are conventionally known multilayer ceramic electronic components. Can be carried out in accordance with the production method. That is, the above-mentioned cutting can be performed by using a cutting blade or dicing or the like, and the firing can be performed using a known and commonly used firing furnace. It can be carried out arbitrarily according to the manufacturing method of the multilayer ceramic electronic component.

[0013]

In the present invention, in the stage of the mother ceramic laminate, a part of the solvent and moisture contained in the mother ceramic laminate are scattered by being left under the reduced pressure as described above. As a result, the content of the binder and water in each of the laminated chips obtained by cutting is reduced. Accordingly, the bonding of the cut laminated chips is effectively suppressed by the reduction in the content of the water and the solvent.

That is, in the present invention, it is inevitable that a certain amount of water and a solvent are contained in obtaining the mother ceramic laminate, but after obtaining the mother ceramic laminate, the above-mentioned water content is removed. And that the content of the solvent may be reduced, and that the bonding of the laminated chip after cutting is caused by the contained moisture and solvent, and the above-mentioned moisture and solvent are mixed at the mother ceramic laminate stage. It is characterized in that coalescence between individual stacked chips is suppressed by scattering a part.

[0015]

According to the present invention, in the stage of the mother ceramic laminate, a part of the solvent and the moisture is scattered by being left under reduced pressure, and the content of the moisture and the solvent in the mother ceramic laminate is reduced. Is done. Accordingly, since the content of the water and the solvent is also reduced in each of the laminated chips obtained by cutting, the bonding of the laminated chips can be effectively suppressed.

Therefore, according to the present invention, it is difficult for the laminated chips to be bonded to each other, so that a sintered chip having a desired shape can be obtained, and the occurrence of cracks and chipping of the sintered chip can be suppressed. can do. Therefore, the defective product rate of the ceramic multilayer electronic component can be reduced.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be clarified by describing one embodiment of the present invention. A ceramic slurry obtained by kneading barium titanate powder, a vinyl acetate resin (containing vinyl acetate and a plasticizer as a main component) as a binder, and water as a solvent is formed into a sheet by a doctor grade method, and has a thickness of 20 μm. A ceramic green sheet was obtained.

As shown in FIG. 2, a conductive paste is printed on one main surface of the ceramic green sheets 11 and 12 obtained as described above by screen printing, and a plurality of 1.0 μm-thick internal electrodes 13 and 12 are formed. 14 were aligned.

A total of 16 ceramic green sheets 11 and 12 on which internal electrodes are formed are alternately laminated, and a plurality of ceramic green sheets on which no external electrodes are printed are laminated one above the other and pressed in the thickness direction. Thus, a mother ceramic laminate 15 was obtained (see FIG. 3).

The mother ceramic laminate 15 obtained as described above was left under a pressure of 8000 Pa for 60 minutes. Thereafter, the mother ceramic laminate 15 was cut in the thickness direction to obtain individual laminate chips having a planar shape of 1.6 mm × 0.8 mm.

The plurality of laminated chips obtained as described above were fired by leaving them at a temperature of 1300 ° C. for 2 to 4 hours to obtain sintered chips. A conductive paste was applied to both end surfaces of the obtained sintered body chip and baked to form a pair of external electrodes, thereby obtaining a multilayer capacitor.

At the stage of sintering the individual laminated chips cut after the pretreatment step as described above, none of the laminated chips were bonded and sintered.
For comparison, when the pretreatment step of leaving the substrate under the reduced pressure was not performed, the bonding of the stacked chips occurred at a rate of 1.53% (per 1,000 pieces), and therefore, the bonding was performed at the same rate. An integrated sintered body chip was generated. Therefore, according to the present example, it can be seen that the pretreatment step in which the laminated chips are left under reduced pressure can reliably prevent the bonding of the laminated chips, and thus a desired sintered chip can be obtained. .

Although the above embodiment has been described with reference to an example in which the present invention is applied to a method of manufacturing a multilayer capacitor, the present invention manufactures a ceramic multilayer electronic component by cutting a mother ceramic multilayer to obtain individual multilayer chips. The method can be generally applied. Therefore, the present invention can be applied to a method of manufacturing another multilayer ceramic electronic component such as a multilayer ceramic piezoelectric component and a multilayer inductor.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a laminated chip.

FIGS. 2A and 2B are plan views respectively showing a mother ceramic green sheet and an internal electrode pattern formed thereon.

FIG. 3 is a perspective view showing a mother ceramic laminate.

[Explanation of symbols]

 11, 12: mother ceramic green sheet 13, 14, ... internal electrode 15: mother ceramic laminate

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H01G 4/12 364 H01G 13/00 391

Claims (1)

(57) [Claims] 1. A step of preparing an unfired mother ceramic laminate in which a plurality of internal electrodes are juxtaposed and embedded, and a step of pressing the mother ceramic laminate in a thickness direction.
And a pretreatment step of leaving the pressurized mother ceramic laminate under reduced pressure; and after the pretreatment step, cutting the mother ceramic laminate into laminate chips of individual ceramic electronic component units. A method for manufacturing a multilayer ceramic electronic component, comprising: a step of firing the ceramic laminate chip obtained by the cutting.