JPH11345742A - Manufacture of multilayer ceramic electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing multilayer ceramic electronic device in which delamination between ceramic layers or stripping of inner electrode from ceramic layer is retarded in sintered ceramic. SOLUTION: A unfired mother laminate 6 having a plurality of inner electrodes 4, 5 laminated through a ceramic layer is prepared. When the mother laminate 6 is pressed in the laminating direction and cut into individual units of multilayer ceramic electronic device, it is cut such that the laminate is removed over a width at (1/3)X or more substantially in the center of adjacent electronic device parts, where X is the interval between the inner electrode 4 of a multilayer ceramic electronic device 7 and the inner electrode 4 of an adjacent multilayer ceramic electronic device 8. The resulting laminate is fired to obtained a sintered laminate and an outer electrode is formed on the outer surface thereof.

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 method for dividing a laminate of individual electronic components from an unfired mother laminate. The present invention relates to a method for manufacturing a multilayer ceramic electronic component with improved processes.

[0002]

2. Description of the Related Art Conventionally, in manufacturing a multilayer ceramic electronic component, in order to enhance mass productivity, an unfired mother laminate is obtained, and the mother laminate is cut in a predetermined direction to obtain an individual product. Of the multilayer ceramic electronic component.

[0003] First, an unfired mother laminate is prepared in which a plurality of laminated ceramic electronic parts in which a plurality of internal electrodes are laminated via ceramic layers are formed at predetermined intervals. Next, after the mother laminate is pressed in the stacking direction, the mother laminate is cut in a predetermined direction in order to divide the laminate into individual laminated ceramic electronic component units. Thereafter, the laminate of each individual multilayer ceramic electronic component obtained by cutting is fired,
A ceramic sintered body in which a plurality of internal electrodes are overlapped via a ceramic layer has been obtained.

In cutting the mother laminate, a cutting blade or a dicer has been used. FIG.
With reference to FIG. 6 and FIG. 6, the cutting step in the conventional method for manufacturing a multilayer ceramic electronic component will be described.

FIG. 5 is a partially cutaway sectional view for explaining a step of cutting a mother laminate using a cutting blade. In the mother laminate 51, a plurality of internal electrodes 52 are laminated via a ceramic layer to form laminated ceramic electronic component parts 53 and 54. In FIG. 5, although not particularly shown, the laminated ceramic electronic component parts 53 and 54 are not shown.
Besides, many multilayer ceramic electronic components are similarly configured.

After obtaining the mother laminate 51, first,
Pressure is applied in the stacking direction to bring the ceramic layer and the internal electrode into close contact. Thereafter, the mother laminate 51 is cut along the dashed line A by using the cutting blade 55 in order to divide the multilayer ceramic electronic component into partial units. That is, at the center of the gap between the internal electrodes 52, 52 of the adjacent laminated ceramic electronic component parts 53, 54, the mother laminate 51 is cut along the broken line A using the cutting blade 55.

By this cutting, the multilayer ceramic electronic component portion 53 and the multilayer ceramic electronic component portion 54 are divided. By cutting the mother laminate 51 using the cutting blades 55 in this manner, individual laminated ceramic electronic component parts 53 and 54 are obtained. In the cutting using the cutting blade 55, the mother laminate 51 is merely divided along the broken line A, and a part of the mother laminate 51 is hardly removed by the cutting.

On the other hand, as shown in FIG. 6, a method of cutting a mother laminate 51 using a dicer 56 is also used. In the method using the dicer 56, as in the case of FIG.
The mother laminated body 51 is cut at substantially the center of the interval between them. However, when the dicer 56 is used, the unsintered ceramic portion constituting the mother laminate 51 is removed according to the cutting width of the dicer 56.

[0009]

In a multilayer ceramic electronic component such as a multilayer capacitor, more internal electrodes are laminated and the thickness of the ceramic layer between the overlapping internal electrodes is reduced in order to reduce the size. Is getting thinner. As a result, after obtaining the mother laminate 51 as described above, when a multilayer ceramic electronic component is obtained by a method in which the ceramic layer and the internal electrode are brought into close contact with each other by pressing in the stacking direction and cut, On the end face of the sintered body, there has been a problem that a phenomenon called delamination, that is, delamination of the ceramic layer tends to occur.

An object of the present invention is to provide a method for efficiently manufacturing a multilayer ceramic electronic component using a mother laminate, in which delamination between ceramic layers in a finally obtained multilayer ceramic electronic component is unlikely to occur. An object of the present invention is to provide a method for manufacturing a ceramic electronic component.

[0011]

According to a first aspect of the present invention, there is provided a method of manufacturing a multilayer ceramic electronic component, wherein a portion of the multilayer ceramic electronic component in which a plurality of internal electrodes are stacked via a ceramic layer is disposed at a predetermined interval. Preparing a plurality of unfired mother laminates formed at a distance from each other; pressing the mother laminate in a stacking direction; and laminating the mother laminate in individual multilayer ceramic electronic component units. When the space between the internal electrode of the multilayer ceramic electronic component portion and the internal electrode of the multilayer ceramic electronic component portion adjacent to the electronic component portion is defined as X when cutting to divide into the body, the adjacent electronic component A step of cutting the mother laminate such that a portion of the laminate having a width of (１ ／) X or more is removed at a substantially central portion between the portions; A step of firing a laminate of individual multilayer ceramic electronic component units to obtain a sintered body; and a step of forming an external electrode on the outer surface of the sintered body so as to be connected to an internal electrode. And

In the invention according to claim 2, the cutting is performed by:
The cutting is performed using a dicer having a cutting width of (１ ／) X or more. According to the third aspect of the invention, a multilayer capacitor is manufactured as the multilayer ceramic electronic component.

Hereinafter, the present invention will be described in detail. In a conventional multilayer ceramic electronic component, as a result of examining the reason why delamination tends to occur when miniaturization and multilayering are promoted, the mother multilayer was cut into individual multilayer ceramic electronic component units. At this time, distortion occurred near the cut surface, and it was confirmed that delamination due to the distortion occurred after firing.

That is, in the production of a multilayer ceramic electronic component, when the number of laminated internal electrodes is increased, and miniaturization and multi-layering are promoted, when a mother laminate is pressed and then pressed, the internal electrodes 52 are laminated. There is a large difference in the way in which pressure is applied between the portion where the pressure is applied and the portion B where the layers are not stacked (see FIG. 5). In the portion B where the internal electrodes 52 are not laminated, pressure is hard to be applied, so that the density is low, and conversely, in the portion where the internal electrodes 52 are laminated, pressure is easily applied, and the density after pressurization is increased. I have.

Accordingly, a distortion as shown by a broken line C in FIG. 6 occurs in the unfired ceramic layer between the portion where the internal electrode 52 is laminated and the portion B where the internal electrode 52 is not laminated.
This distortion is caused by the adjacent multilayer ceramic electronic components 53 and 5.
It is considered that it is the largest at the center of the gap between the four.

Therefore, when the mother laminate 51 is cut using the cutting blade 55 and the dicer 56, distortion remains near the cut surface, and the firing obtained by firing the individual laminates in a later step is performed. It is considered that delamination has occurred in the surface corresponding to the cut surface in the union.

In the present invention, in order to suppress the delamination caused by the distortion of the portion B where the internal electrodes are not stacked, the distance between the internal electrodes of the adjacent multilayer ceramic electronic components is set to X as described above. In some cases, the mother laminate is cut such that a laminate having a width of (１ ／) X or more is removed at a substantially central portion between adjacent electronic component parts, thereby providing a laminate having a large distortion. , Thereby suppressing the occurrence of the delamination.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below more specifically with reference to the drawings. In the present embodiment, a multilayer capacitor 1 schematically shown in FIG. 3 is manufactured using a mother laminate. First, mother ceramic green sheets 2 and 3 shown in FIG. 4 are prepared. The mother ceramic green sheets 2 and 3 are obtained by sheet-forming a ceramic slurry mainly composed of an appropriate dielectric ceramic such as a barium titanate-based ceramic.

Mother's ceramic green sheets 2 and 3
The internal electrodes 4 and 5 are formed on the upper surface by screen printing, for example, a conductive paste mainly composed of Ni.

Next, a plurality of mother ceramic green sheets 2 and 3 are alternately laminated, and an appropriate number of plain ceramic green sheets on which no internal electrodes are printed are laminated above and below to obtain a mother laminate. .

After the mother laminate thus obtained is pressed in the laminating direction, it is cut as shown in FIGS. That is, as shown in FIG.
In this example, the laminated ceramic electronic component portions 7, 8 in which the internal electrodes 4, 5 described above are alternately laminated are arranged at predetermined intervals. FIG. 1 is a cross-sectional view of a portion cut along a portion corresponding to line EE in FIG. FIG.
Corresponds to a cross-sectional view of a portion of the mother laminate 6 cut along the paper surface-back direction of FIG. That is, FIG.
FIG. 4 is a cross-sectional view of a portion corresponding to a portion along the line DD of FIG.

In cutting the mother laminate 6 to obtain individual multilayer ceramic electronic component parts 7 and 8,
When the distance between the internal electrode 4 of the multilayer ceramic electronic component portion 7 and the internal electrode 4 of the adjacent multilayer ceramic electronic component portion 8 is X, the two adjacent electronic component portions 7, 8
The cutting is performed so that the laminated body portion having a width of (１ ／) X or more is removed at a substantially central portion between them. In this embodiment,
In order to perform this cutting, a dicer 9 having a cutting width of (１ ／) X or more is used.

As described above, the mother laminate 6 is cut in the thickness direction using the dicer 9 to obtain individual multilayer ceramic electronic component parts 7 and 8. In addition, as shown in FIG.
On the end face in a direction orthogonal to the portion shown in FIG. 1, the individual multilayer ceramic electronic component portions 7 and 10 are adjacent to each other. In this case, the distance between the internal electrode 5 of the multilayer ceramic electronic component portion 7 and the internal electrode 5 of the adjacent multilayer ceramic electronic component portion 10 is X, and the center between the adjacent electronic component portions 7 and 10 is substantially the center. In the part, similarly, the mother laminate 6 is cut so that the laminate portion having a width of (１ ／) X or more is removed. That is, in the cross-sectional direction shown in FIG. 2, the internal electrodes 4 are formed so as to extend between adjacent multilayer ceramic electronic component parts. You.

As described above, a laminate of individual multilayer ceramic electronic component parts is obtained and fired according to a conventional method, whereby a sintered body of each multilayer ceramic electronic component unit can be obtained. Thus, the sintered body 11 shown in FIG. 3 is obtained. In the sintered body 11, a plurality of internal electrodes 4A and 5A are alternately stacked.

The internal electrode 4A is extended to one end face 11a of the ceramic sintered body 11, and the internal electrode 5A is extended to an end face 11b opposite to the end face 11a. By coating and baking, for example, an Ag paste so as to cover the end surfaces 11a, 11b, the external electrodes 12,
Thus, a multilayer capacitor 1 is obtained.

According to the manufacturing method of this embodiment, when the mother laminate 6 is cut in the thickness direction as described above, the width of (1/3) X or more is approximately at the center between the adjacent electronic parts. The mother laminate 6 is cut so that the laminate portion is removed. Therefore, since the portion of the laminate having the largest distortion is removed by cutting, the distortion in the vicinity of the cut surface of each obtained laminate is reduced. Therefore, the occurrence of delamination on the side surface and the end surface of the sintered body 11 is effectively suppressed. This will be described based on specific experimental examples.

As the multilayer capacitor 1, 1.6 ×
It has dimensions of 0.8 × 0.8 mm, 160 internal electrodes mainly composed of Ni are laminated, the thickness of the ceramic layer between adjacent internal electrodes is 3 μm, and the design capacitance value is 1 μF. Was manufactured. In this case, when cutting the mother laminate 6, the width of the portion where the laminate is removed by cutting is set to 0, 0.1X, 0.2X, 0 with respect to the interval X as shown in Table 1 below. .3X and 0.5X to obtain laminates. Then, the obtained laminate was fired to obtain a sintered body. With respect to each of the thus obtained sintered bodies, the side face and the end face were observed, and the rate of occurrence of peeling and the rate of occurrence of delamination between the internal electrode and the ceramic layer were evaluated in the following manner.

Ratio of peeling between internal electrode and ceramic layer: The ratio of defective products was calculated by visual inspection of appearance. Delamination generation rate: A surface parallel to the length direction and the laminating direction of the sintered body was polished, and the occurrence rate of defects was calculated from inspection with an electron microscope.

The results are shown in Table 1 below. In Table 1, the above evaluations are average values for 1000 sintered bodies.

[0030]

[Table 1]

As is clear from Table 1, when the cut width, that is, the width of the portion where the mother laminate is removed by cutting is set to 0.3X or more, peeling and delamination between the internal electrode and the ceramic layer are performed. When the cutting width was 0.2X or less, peeling between the internal electrode and the ceramic layer and occurrence of delamination were observed. Therefore, as in the above embodiment, the cutting width between adjacent multilayer ceramic electronic component portions is set to 0.
It can be seen that when the value is 3X or more, peeling between the internal electrode and the ceramic layer and delamination between the ceramic layers can be reliably prevented.

In the above embodiment, a method of manufacturing a multilayer capacitor has been described. However, the present invention relates to a method for manufacturing a multilayer capacitor in which a ceramic layer is stacked via a plurality of internal electrodes. Since it suppresses the occurrence of delamination due to distortion, not only multilayer capacitors but also multilayer varistors, multilayer ceramic substrates,
It can be used for manufacturing various multilayer ceramic electronic components such as a multilayer ceramic piezoelectric component and a multilayer thermistor, and the same effects as described above can be obtained.

[0033]

In the method for manufacturing a multilayer ceramic electronic component according to the first aspect of the present invention, when the mother laminate is cut to obtain a laminate of individual multilayer ceramic electronic components, adjacent multilayer ceramic electronic components are obtained. Assuming that the interval between the internal electrodes between the component parts is X, the mother lamination is performed so that a laminate part having a width of (１ ／) X or more is removed at a substantially central portion between adjacent electronic component parts. The body is severed. Therefore, since the portion having the largest distortion is removed by cutting, the vicinity of the cut surface of each obtained laminate is reduced in distortion. Therefore, peeling between the internal electrode and the ceramic layer and delamination between the ceramic layers in the sintered body obtained by firing the laminate can be effectively suppressed, and reliability such as moisture resistance can be improved. It is possible to stably provide excellent multilayer ceramic electronic components.

According to the second aspect of the present invention, since the cutting is performed by using a dicer having a cutting width of (３) X or more, a dicer having a different cutting width is prepared instead of the conventional dicer. In this way, it is possible to reliably prevent the occurrence of delamination and the separation between the internal electrode and the ceramic layer in the same steps as in the related art without increasing the number of steps.

According to the third aspect of the present invention, since a multilayer capacitor is obtained as the multilayer ceramic electronic component, it is possible to easily cope with miniaturization and multilayering of the multilayer capacitor.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view for explaining a step of cutting a mother laminate using a dicer in one embodiment of the present invention.

FIG. 2 is a partially cutaway cross-sectional view for explaining a step of cutting the mother laminate using a dicer in cross sections along different directions of the mother laminate illustrated in FIG. 1;

FIG. 3 is a sectional view showing a multilayer capacitor as a multilayer ceramic electronic component obtained in one embodiment of the present invention.

FIGS. 4A and 4B are plan views respectively illustrating a mother ceramic green sheet prepared in an embodiment of the present invention and an internal electrode pattern formed thereon.

FIG. 5 is a partially cutaway sectional view for explaining a step of cutting a mother laminate by a cutting blade in a conventional method for manufacturing a multilayer capacitor.

FIG. 6 is a partially cutaway cross-sectional view for explaining a step of cutting a mother laminate using a dicer in manufacturing a conventional multilayer capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Multilayer capacitor (multilayer ceramic electronic component) 2, 3 ... Mother ceramic green sheet 4, 5 ... Internal electrode 4A, 5A ... Internal electrode 6 ... Mother laminated body 7, 8 ... Individual multilayer ceramic electronic component part 9 ... Dicer 10 ... Multilayer ceramic electronic parts 11 ... Sintered body 12,13 ... External electrode

Claims (3)

[Claims] 1. A step of preparing an unfired mother laminate in which a plurality of laminated ceramic electronic component parts in which a plurality of internal electrodes are laminated via a ceramic layer are formed at predetermined intervals. Pressing the mother laminate in the laminating direction; and cutting the mother laminate into individual laminate ceramic electronic component unit laminates, wherein the internal electrodes of the multilayer ceramic electronic component portion and the electronic Assuming that the distance between the internal electrode of the multilayer ceramic electronic component portion adjacent to the component portion is X, a laminate portion having a width of (１ ／) X or more is substantially at the center between the adjacent electronic component portions. Cutting the mother laminate in the thickness direction so as to be removed; and firing the individual multilayer ceramic electronic component unit laminate obtained in the cutting step to obtain a sintered body. Forming an external electrode on the outer surface of the sintered body so as to be connected to the internal electrode. 2. The method according to claim 1, wherein the cutting is performed using a dicer having a cutting width of (サ ー) X or more. 3. The method for manufacturing a multilayer ceramic electronic component according to claim 1, wherein the multilayer ceramic electronic component is a multilayer capacitor.