JPH10270283A - Manufacture of multilayer ceramic electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it hard to generate step-differences of a surface and peeling of ceramic layers which are caused by existence of inner electrodes, in a laminated block which is obtained by laminating and pressing a plurality of ceramic green sheets, in order to manufacture a multilayer ceramic electronic component such as a multilayer ceramic capacitor. SOLUTION: A process, wherein a laminated member block 1 is pressed, is devided into a preliminary press processes with rigid body press using a die 6 and a punch 7, and a final press process using a static hydraulic pressure press wherein the laminated member block 1 is vacuum-packed in a bag 10 and pressure, is applied in water or using rigid body press interposing an elastic member and these processes are performed in succession. At this time, press pressure applied in the preliminary press process is selected to be 5-75% of press pressure applied in the final press process.

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 step of pressing a plurality of stacked ceramic green sheets.

[0002]

2. Description of the Related Art For example, when manufacturing a multilayer ceramic electronic component such as a multilayer ceramic capacitor,
A plurality of ceramic green sheets are prepared, and a stack is obtained by stacking the ceramic green sheets. Then, the stack is pressed. In addition, on the specific ceramic green sheets stacked as described above, depending on the function of the multilayer ceramic electronic component to be obtained, such as internal electrodes for forming capacitors, resistors, inductors, varistors, filters, etc. Various internal circuit elements are formed in advance.

In the pressing step described above, a rigid press for applying a rigid body to the surface of the laminate to be pressed is applied, or a hydrostatic press for applying a hydrostatic pressure to the surface of the laminate to be pressed is used. Have been applied. In addition, in order to realize the miniaturization and high performance of such a multilayer ceramic electronic component,
Ceramic green sheets are being made thinner and more multilayered.

[0004]

In the step of pressing a laminate, when a rigid press is applied, the thickness of the internal circuit element itself formed inside the rigid press causes the portion where the internal circuit element exists to be removed. The application of the pressing pressure is different between the other parts and the part where the internal circuit element is not formed. As described above, this occurs more remarkably as the ceramic green sheets constituting the laminate are made thinner and more multilayered.

[0005] When a plurality of chips are obtained by cutting out a laminated block in which the pressing is partially insufficient in spite of pressing as described above, peeling is likely to occur between ceramic layers. In addition, in order to solve the above-mentioned problem, before performing the final rigid press process, every time the ceramic green sheets are stacked, the first stage temporary press by the rigid press is performed, and a certain number of laminations is reached. At times, it has been proposed to carry out a second stage temporary press by a rigid press again. However, this method not only has a problem that the manufacturing time is long, but also encounters a problem that peeling is likely to occur at the interface where the second stage temporary press is performed.

On the other hand, in the pressing step, when applying a hydrostatic press or when applying a rigid press via an elastic body such as rubber, the above-mentioned problem of peeling is improved. However, as shown in FIG. 3, on the surface of the laminate block 1 after pressing,
Irregularities indicated by the steps 2 may occur, so that the chips cut out of the laminated block 1 do not have a rectangular parallelepiped shape, but have a “kamaboko” shape in which at least one surface of the rectangular parallelepiped is expanded. As a result, the attitude of the chip during the manufacturing of the multilayer ceramic electronic component is not stable, and the efficiency of the manufacturing is reduced.At the same time, the stability of the attitude at the time of mounting the obtained multilayer ceramic electronic component is lacking, and the reliability of the mounting is also reduced. Will be reduced.

[0007] When the above-mentioned deformation is largely generated, undesired deformation is generated also in, for example, the internal electrode 3 as an internal circuit element, leading to a problem that the reliability of the obtained multilayer ceramic electronic component itself is reduced. Develop. Accordingly, an object of the present invention is to provide a method for manufacturing a multilayer ceramic electronic component that can solve the above-described problems.

[0008]

According to the present invention, a plurality of ceramic green sheets are prepared, an internal circuit element is formed on a specific one of the plurality of ceramic green sheets, and the plurality of ceramic green sheets are stacked. Pressing a plurality of stacked ceramic green sheets, including the respective steps, is directed to a method for manufacturing a multilayer ceramic electronic component, and has the following configuration to solve the above technical problem It is characterized by.

That is, the above-mentioned pressing step includes a preliminary pressing step using a rigid press and a final pressing step using a hydrostatic pressing or a rigid pressing through an elastic body. It is characterized in that it is selected at 5 to 75% of the pressing pressure applied in the final pressing step. The pressing pressure applied in the above-mentioned preliminary pressing step is more preferably selected to be 10 to 30% of the pressing pressure applied in the final pressing step.

[0010]

FIG. 1 is a view for explaining a method of manufacturing a multilayer ceramic electronic component according to an embodiment of the present invention. The main steps included in this manufacturing method are (1).
To (4). In this embodiment, a multilayer ceramic capacitor is manufactured as a multilayer ceramic electronic component.

FIGS. 1A and 1B show a ceramic green sheet 4. A plurality of ceramic green sheets 4 are prepared, and an internal electrode 3 as an internal circuit element is formed on a specific one of the plurality of ceramic green sheets 4 as shown in FIG. Next, as shown in FIG. 1 (2), a plurality of ceramic green sheets 4 are stacked. At this time, the plurality of ceramic green sheets 4 on which the internal electrodes 3 are formed are formed.
Are positioned in the middle, and a plurality of ceramic green sheets 4 on which no internal electrodes are formed are positioned at both ends.

Next, the laminate block 1 obtained as described above is subjected to a pressing step. This pressing step is sequentially performed by dividing into a preliminary pressing step shown in FIG. 1 (3) and a final pressing step shown in FIG. 1 (4). First,
In the preliminary press step shown in FIG. 1 (3), a rigid press is applied. That is, a rigid press device including a rigid die 6 having the concave portion 5 and a rigid punch 7 operating while fitting into the concave portion 5 is prepared. Die 6
The laminated block 1 obtained through the process shown in FIG. 1 (2) is arranged in the concave portion 5 of FIG. 1, and the punch 7 is operated in the direction of arrow 8 to press the laminated block 1 by a rigid press. Pressure is applied.

Next, after finishing such a pre-pressing step, the laminate block 1 is taken out of the die 6 and
As shown in (4), it is placed in the bag 10 while being placed on the base 9 made of a rigid body and vacuum-packed.
In this state, a hydrostatic pressing step as a final pressing step is performed. That is, the laminated block 1 that has been vacuum-packed is immersed in, for example, water in a hydrostatic pressing device, and by pressing this water, as shown by an arrow 11, the laminated block 1 is , And the pressure is evenly applied from the surroundings.

The press pressure applied in the preliminary press step shown in FIG. 1 (3) is selected to be 5 to 75% of the press pressure applied in the final press step shown in FIG. 1 (4). Regarding the above-mentioned pressing pressure, more preferably, the pressing pressure applied in the preliminary pressing step is selected to be 10 to 30% of the pressing pressure applied in the final pressing step.

The optimum conditions for the pressing pressure are determined by factors such as the type and amount of an organic vehicle component such as a binder contained in the ceramic green sheet 4 constituting the laminate block 1 or the particle size of the ceramic. Is appropriately selected in consideration of these factors. After the final pressing step shown in FIG. 1 (4) is completed and the laminate block 1 is pulled out of the water, the bag 10 is broken and the inside laminate block 1 is taken out.
Next, the laminated block 1 is cut, a plurality of chips cut out from the laminated block 1 are fired, and external electrodes are provided on the surfaces of the fired chips, so that an intended multilayer ceramic capacitor is obtained. Is obtained.

FIG. 2 illustrates another embodiment of the present invention. In the embodiment shown in FIG. 1, in the final pressing step, a hydrostatic press is applied as shown in FIG. 1 (4), but instead of this hydrostatic press, an elastic body 12 as shown in FIG. Rigid press through may be applied. Referring to FIG. 2, as in the case of the rigid pressing device shown in FIG. 1 (3), a die 14 made of a rigid body having a concave portion 13 and a punch 15 made of a rigid body that operates while fitting into the concave portion 13 A rigid press device is provided. In the concave portion 13 of the die 14, the laminated block 1 that has been subjected to the pre-pressing step shown in FIG. 1 (3) is arranged, and the elastic body 12 made of, for example, rubber is arranged thereon. By operating the punch 15 in the direction of the arrow 16 in this state, a pressing pressure is applied to the laminate block 1 by the rigid press via the elastic body 12.

Also in this embodiment, the pressing pressure applied in the preliminary pressing step shown in FIG. 1 (3) is 5 to 7 times the pressing pressure applied in the final pressing step shown in FIG.
5%, more preferably 10 to 30%. As described above, the present invention has been mainly described with reference to the method for manufacturing the multilayer ceramic capacitor according to the illustrated embodiment.
The present invention can be applied not only to the multilayer ceramic capacitor but also to a multilayer ceramic electronic component functioning as a resistor, an inductor, a varistor, a filter, or the like, or to a multilayer ceramic electronic component in which these functional elements are combined.

In the illustrated embodiment, the internal circuit element formed inside the multilayer body is an internal electrode. However, as described above, the present invention provides various multilayer ceramic electronic devices having arbitrary functions. Since the present invention is applicable to components, various modes can be considered as internal circuit elements. For example,
The internal circuit element may be, for example, a circuit element having relatively high electrical resistance or other electrical characteristics, in addition to a circuit element having good conductivity such as an internal electrode.

In the illustrated embodiment, the pressing step is divided into two steps, a pre-pressing step and a final pressing step. However, another pressing step may be performed.

[0020]

EXAMPLE In order to confirm the effects of the present invention, a laminated block 1 was obtained in accordance with the steps shown in FIG. 1 as described below. That is, first, referring to FIG.
From ceramic slurry containing binder and plasticizer,
A ceramic green sheet 4 having a thickness of 5 μm was formed, and an internal electrode 3 having a coating thickness of 3 μm was formed on a specific ceramic green sheet 4 by printing.

Next, as shown in FIG. 1B, 200 ceramic green sheets 4 on which the internal electrodes 3 were formed were stacked, and 30 ceramic green sheets 4 on which no internal electrodes were formed were stacked on both sides. . Here, the difference in thickness between the part where the internal electrode 3 is formed and the part where it is not is 3 μm × 200 = 600 μm.

Next, as shown in FIG. 1 (3), a preliminary pressing step by a rigid press was performed. Here, as described in Table 1 below, the press pressure applied in the preliminary press step was changed in a range of 0% to 90% of the press pressure in the final press step by the next hydrostatic press. Next, as shown in FIG. 1 (4), a final pressing step by an isostatic press was performed.

The laminate block 1 thus obtained
While measuring the step 2 shown in FIG. 3 on the surface of the above, a plurality of chips were cut out from the laminate block 1,
The presence or absence of peeling on the chip was observed, and the peeling occurrence rate was determined. The results are shown in Table 1 below.

[0024]

[Table 1] As can be seen from Table 1, the pre-press pressure is 5 to 75%
When the ratio is within the range, favorable results are shown in both the surface step and the peeling occurrence rate.

On the other hand, when the pre-press pressure is 0%, that is, when the pre-press step is not applied,
The surface step appears as large as 150 μm.
Further, when the pre-pressing pressure is increased to 90%, the pressing effect of the subsequent final pressing step is not so much exhibited, and peeling occurs at a rate of 5%.

[0026]

As described above, in the present invention, the pressing step is performed in two stages, a pre-pressing step and a final pressing step, and a rigid press is applied in the pre-pressing step, and in the final pressing step, A hydrostatic press or a rigid press through an elastic body is applied.

Therefore, in the pre-pressing step, the laminate is pressed down in advance. At this time, since a rigid press is applied, there is no unevenness on the surface of the laminate due to the partial presence of the internal circuit element in the laminate. Next, the final pressing step is performed on the laminate that has been previously reduced in the preliminary pressing step, so that in this final pressing step, it is possible to prevent the laminate from being reduced much, and it is also possible to use a hydrostatic press or Even if a rigid press using an elastic body is applied, it is possible to prevent the surface of the laminate from having a large amount of unevenness due to the partial presence of the internal circuit element in the laminate.

Moreover, in the present invention, the press pressure applied in the pre-press step is selected to be 5 to 75% of the press pressure applied in the final press step, so that even after the pre-press step is performed, The laminate has room for the pressing effect of the final pressing step. Therefore, even in the portion where the internal circuit element does not exist, the effect of increasing the adhesion between the ceramic layers by the hydrostatic pressing in the final pressing step or the rigid pressing through the elastic body is sufficiently exerted.

From the above, according to the present invention,
Even if the ceramic green sheets constituting the laminate are thinned and multilayered, the disadvantage that peeling occurs between the ceramic layers when a plurality of chips are obtained by cutting out the laminate block is eliminated. Kamaboko is a chip cut out of a complex laminate block
The problem of stagnation is also eliminated. In addition, the problem that undesired deformation occurs in the internal circuit element and lowers the reliability of the obtained multilayer ceramic electronic component is also solved.

Further, according to the present invention, since the pressing step is only performed separately in the pre-pressing step and the final pressing step, this does not significantly reduce the production efficiency.

[Brief description of the drawings]

FIG. 1 is a sectional view sequentially showing main steps included in a method for manufacturing a multilayer ceramic capacitor as a multilayer ceramic electronic component according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a step that is included in a method for manufacturing a multilayer ceramic capacitor according to another embodiment of the present invention and is an alternative to the step shown in FIG.

FIG. 3 is a sectional view showing a part of a laminate block 1 which is interesting for the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminated block 3 Internal electrode 4 Ceramic green sheet 6,14 Die 7,15 Punch 10 Bag 12 Elastic body

Claims (1)

[Claims] 1. A plurality of ceramic green sheets are prepared, an internal circuit element is formed on a specific one of the plurality of ceramic green sheets, the plurality of ceramic green sheets are stacked, and the stacked ceramic green sheets are stacked. Pressing the sheet, comprising the respective steps, in the method for manufacturing a multilayer ceramic electronic component, wherein the pressing step, a preliminary pressing step by a rigid press, and a final pressing step by a rigid press through a hydrostatic press or an elastic body The method for producing a multilayer ceramic electronic component, wherein the press pressure applied in the preliminary press step is selected to be 5 to 75% of the press pressure applied in the final press step.