JP3044994B2 - 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, and more particularly to an improvement in a process of compression-molding a ceramic laminate obtained by laminating a plurality of ceramic green sheets. .

[0002]

2. Description of the Related Art Multilayer ceramic electronic components of interest to the present invention include, for example, multilayer ceramic capacitors, multilayer ceramic composite components, multilayer ceramic multilayer circuit boards, and the like. Such a method of manufacturing a laminated ceramic electronic component includes a step of laminating a plurality of ceramic green sheets to obtain a ceramic laminated body, and a step of compressing the ceramic laminated body in the laminating direction. . If the ceramic laminate is for obtaining a plurality of components, it is compression molded, cut into individual components, and then subjected to a firing step. If the ceramic laminate is for obtaining one component, it is subjected to a firing step as it is after compression molding.

In the step of compressing a ceramic laminate as described above, attention has been paid to applying an isostatic pressing method in that the pressure for compression molding can be applied uniformly. Japanese Patent Application Laid-Open No. 2-161713 describes several methods for compression-molding a ceramic laminate by applying an isostatic pressing method. Among the methods described in this publication, a compression molding step that is of interest to the present invention is shown in FIG.

FIG. 3 shows a ceramic laminate 1 obtained by laminating a plurality of ceramic green sheets. In order to compress such a ceramic laminate 1 in the laminating direction, a die assembly 2 is prepared, and the ceramic laminate 1 is loaded into the die assembly 2.

The die assembly 2 includes a pad member 3, a base member 4, and a frame member 5. A step 6 is provided on the upper surface of the base member 4 to achieve positioning with respect to the frame member 5. The pad member 3 is selected to have such a size that it can be moved toward the main surface of the ceramic laminate 1 while being fitted to the inner periphery of the frame member 5.

The pad member 3 and the ceramic laminate 1
And between the base member 4 and the ceramic laminate 1, elastic sheets 7 and 8 are interposed, respectively. An elastic sheet 9 is arranged outside the pad member 3. Furthermore, the die assembly 2 loaded with the ceramic laminate 1 as described above, together with the elastic sheet 9,
For example, it is put in a bag 10 such as a laminate bag and vacuum-packed. In FIG. 3, although a space is formed between the bag 10 and the die assembly 2, the bag 10 is in close contact with the die assembly 2 and the like after vacuum packing.

The elastic sheet 9 prevents the bag 10 from being broken when pressure is applied from the outside of the bag 10. The outer surface of the die assembly 2 is formed with a rounded portion so that the bag 10 is hardly broken.

[0008] In the state shown in FIG.
Is placed in a water tank of a hydrostatic press (not shown), and water in the water tank is pressurized. Thereby, the ceramic laminate 1 is compressed via the die assembly 2.
Thereafter, the ceramic laminate 1 having been subjected to the compression molding in this manner is taken out of the water tank, the bag 10 is broken, and then taken out of the die assembly 2.

[0009]

As described above, in the step of applying the hydrostatic pressure to compress the ceramic laminate 1 via the die assembly 2, the die assembly 2
Paying attention to the behavior of the pad member 3 with respect to the frame member 5
Is displaced, but the base member 4 is not displaced. Therefore, the action of compressing the ceramic laminate 1 is as follows.
Substantially only by the pad member 3. As a result, there is a difference between the effective pressures applied to the upper main surface and the lower main surface of the ceramic laminate 1, and uneven compression is likely to occur in the compression-molded ceramic laminate 1. FIG. 4 is a schematic cross-sectional view of the compression-molded ceramic laminate 1.

Referring to FIG. 4, an internal conductor 11 formed by printing or the like exists inside a ceramic laminate 1 to be a multilayer ceramic electronic component. Therefore, the thickness of the ceramic laminate 1 is relatively large in the portion where the internal conductor 11 is located, and as a result of compression molding,
Protrusions 12 tend to be formed on the surface. As described above, when the hydrostatic pressure is applied, the pad member 3
Is merely displaced, the protruding portion 12 appears remarkably only on one main surface of the ceramic laminate 1.

Therefore, in the ceramic laminated body 1, as shown by the broken line in FIG. 4, uneven distortion 1 on the upper main surface side and the lower main surface side of the ceramic laminated body 1.
3 and 14 occur. Such uneven distortions 13 and 14 degrade the adhesion of a plurality of ceramic green sheets included in the ceramic laminate 1. As a result, the ceramic laminate 1 is more likely to encounter the problem of layer peeling during such compression molding, or during cutting or firing.

An object of the present invention is to provide a method for manufacturing a multilayer ceramic electronic component that can solve the above-mentioned problems.

[0013]

The present invention provides a die assembly having a structure capable of stacking a plurality of ceramic green sheets to obtain a ceramic laminate, and compressing the ceramic laminate in the laminating direction. Loading the assembly with the ceramic laminate and applying hydrostatic pressure to compress the ceramic laminate through the die assembly;
The present invention is directed to a method for manufacturing a multilayer ceramic electronic component including the respective steps, and in order to solve the above-described technical problems, in the present invention, an improvement is made to a die assembly used. That is, as a die assembly, first and second pad members adapted to exert a pressing action toward both main surfaces thereof with a ceramic laminate interposed therebetween, a ceramic laminate, and first and second pad members And a frame member that guides both the first and second pad members so as to be movable toward each main surface of the ceramic laminate.

[0014]

The die assembly used in the present invention has a first and a second which exert a pressing action toward both principal surfaces of the ceramic laminate when a hydrostatic pressure is applied.
Are moved toward each main surface of the ceramic laminate.

[0015]

Therefore, according to the present invention, it is possible to reduce the difference between the effective pressures applied to the respective principal surfaces of the ceramic laminate, and to substantially equalize the strain generated inside the ceramic laminate. Can be. as a result,
The adhesion of the plurality of ceramic green sheets included in the compression-molded ceramic laminate is improved, and the problem of delamination can be suppressed.

[0016]

1 and 2 correspond to FIGS. 3 and 4, respectively, for explaining an embodiment of the present invention.

FIG. 1 shows a ceramic laminate 21 obtained by laminating a plurality of ceramic green sheets. Such a ceramic laminate 21 is loaded into a die assembly 22. The die assembly 22 has a structure capable of compressing the ceramic laminate 21 in the laminating direction.

More specifically, the die assembly 22 includes first and second pad members 23 and 24 each of which has a pressing action toward both main surfaces thereof with the ceramic laminate 21 interposed therebetween; The laminate 21 and the first and second pad members 23 and 24 are disposed around the first and second pad members 23 and 24 and both the first and second pad members 23 and 24 can be moved toward the main surfaces of the ceramic laminate 21 respectively. And a frame member 25 for guiding as described above. These pad members 23 and 24 and frame member 2
5 are each formed of a rigid body.

Preferably, the ceramic laminate 21
The elastic sheets 26 and 27 are interposed between the first pad member 23 and the ceramic laminate 21 and the second pad member 24, respectively.

The die assembly 22 loaded with the ceramic laminate 21 is put in a bag 28 such as a laminate bag and vacuum-packed. In order to prevent the bag 28 from being broken when a pressure is applied from the outside of the bag 28, it is preferable that the elastic sheets 29 and 30 are disposed on the upper and lower surfaces of the die assembly 22, respectively. Also, a suitable radius is preferably formed on the outwardly facing surface of the die assembly 22, which also prevents the bag 28 from breaking. In FIG. 1, the bag 28 is illustrated with a space formed between the bag 28 and the die assembly 22. However, after the bag 28 is vacuum-packed as described above, the bag 28 is And 30.

In this embodiment, an engaging portion 31 that engages with the peripheral portion of the second pad member 24 is provided at the end of the frame member 25. According to the engagement portion 31, the ceramic laminate 21 and the first and second
Of the die assembly 22 after the ceramic laminate 21 is loaded.
Can be easily handled. However,
If such an advantage is not desired, the frame member 25 may not be provided with the engagement portion 31.

In order to compress and form the ceramic laminate 21, the ceramic laminate 21 is placed in a water tank of a hydrostatic press (not shown) in the state shown in FIG. Then, when the water in the water tank is pressurized, a hydrostatic pressure is applied via the die assembly 22 so as to compress the ceramic laminate 21. At this time, both the first and second pad members 23 and 24 move toward the respective main surfaces of the ceramic laminate 21 with respect to the frame member 25, and the first and second pad members 23 and 24 move. Exerts a substantially uniform effective pressure on the ceramic laminate 21.

As described above, the ceramic laminate 21
Is completed, the ceramic laminate 21 is taken out of the hydrostatic press together with the die assembly 22 and the like, and is taken out of the die assembly 22 after the bag 28 is broken.

FIG. 2 is a schematic sectional view of the compression-molded ceramic laminate 21. Although the thickness of the ceramic laminate 21 is relatively large in the portion where the internal conductor 32 is located, as described above, since a substantially uniform effective pressure is applied to each main surface of the ceramic laminate 21, As a result of the increase in thickness, the ceramic laminate 2
Convex portions 33 and 34 are formed symmetrically on the two main surfaces, respectively. Further, as indicated by broken lines in FIG. 2, on each main surface side of the ceramic laminate 21, the distortions 35 and 36 appear substantially evenly with each other. As a result, the adhesion of the plurality of ceramic green sheets included in the ceramic laminate 21 is improved, and the problem of layer peeling can be reduced.

Generally, the above-mentioned layer peeling tends to appear more remarkably as the number of laminated ceramic green sheets included in the ceramic laminate 21 increases. According to the experiment, when the number of laminated ceramic green sheets included in the ceramic laminated body is increased to 60, 90, and 120, in the conventional method shown in FIG. Although not observed, in the case of 120 laminated layers, layer peeling was observed in 13 of the 500 samples (2.60%). On the other hand, in the method according to the embodiment shown in FIG. 1, no layer peeling occurred up to a lamination number of 120.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a hydrostatic pressure applying step included in a method for manufacturing a multilayer ceramic electronic component according to an embodiment of the present invention is performed.

FIG. 2 is an illustrative sectional view showing a ceramic laminate 21 compression-molded according to the embodiment shown in FIG.

FIG. 3 is a cross-sectional view showing a state in which a hydrostatic pressure applying step included in a conventional method for manufacturing a multilayer ceramic electronic component is performed.

FIG. 4 is an illustrative sectional view showing a ceramic laminate 1 compression-molded by the method shown in FIG.

[Explanation of symbols]

 Reference Signs List 21 ceramic laminate 22 die assembly 23 first pad member 24 second pad member 25 frame member 28 bag

Claims (1)

(57) [Claims] 1. A ceramic laminate is obtained by laminating a plurality of ceramic green sheets, a die assembly having a structure capable of compressing the ceramic laminate in a laminating direction is prepared, and the ceramic laminate is loaded into the die assembly. And applying hydrostatic pressure to compress the ceramic laminate through the die assembly, comprising:
In the method for manufacturing a multilayer ceramic electronic component, the die assembly includes first and second pad members each of which has a pressing action toward both main surfaces thereof with the ceramic multilayer body interposed therebetween; And a frame member disposed around the first and second pad members and guiding both the first and second pad members so as to be movable toward respective main surfaces of the ceramic laminate, respectively. And a method for manufacturing a multilayer ceramic electronic component.