JPH08330178A - Manufacture of multilayer ceramic capacitor - Google Patents

Abstract

PURPOSE: To decide whether the inner electrode of a multilayer ceramic capacitor is formed while being spaced apart by a predetermined gap from the outer surface of a chip with high reliability and efficiency. CONSTITUTION: At a stripe electrodeless part 16 on a plurality of stacked ceramic green sheets 11, 12 constituting a mother laminate for a plurality of chips, a conductive shift detection pattern 17 is formed extending in parallel with the long side 14 of an inner electrode 13 while being spaced apart from a predetermined interval (a). When the gap of inner electrode 13 from the outer surface of a chip obtained by cutting the mother laminate is insufficient, the shift detection pattern 17 is taken into the chip at least partially to cause short circuit of a pair of outer electrodes. Consequently, incorrect state of inner electrode 13 can be grasped by measuring the resistance between the outer electrodes.

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 monolithic ceramic capacitor, and more particularly to an improvement for improving the reliability of the proper position of internal electrodes.

[0002]

2. Description of the Related Art A laminated ceramic capacitor is provided with a rectangular parallelepiped chip obtained by cutting a mother laminated body obtained by stacking and pressing a plurality of ceramic green sheets. FIG. 5 shows a chip 1 for a monolithic ceramic capacitor in a longitudinal sectional view. Inside the chip 1, a plurality of internal electrodes 2 extending parallel to each other are provided.
Are formed. The plurality of internal electrodes 2 alternately reach one or the other end surface of the chip 1 and are electrically connected to external electrodes (not shown) on each end surface of the chip 1.

To obtain the above-mentioned chip 1, ceramic green sheets 3 and 4 as shown in FIG. 6 are prepared. On these ceramic green sheets 3 and 4, a plurality of internal electrodes 2 having long sides 5 and short sides 6 are arranged in rows and columns while orienting the respective long sides 5 and short sides 6 in the same direction. Has been formed. These ceramic green sheets 3 and 4 are alternately stacked in the following manner. That is, one internal electrode 2 is commonly opposed to each two internal electrodes 2 adjacent in the long side 5 direction via a certain ceramic green sheet 3 or 4, and each two internal electrodes 2 adjacent in the short side 6 direction. A strip-shaped electrode absent portion 7 defined between two internal electrodes 2
Are aligned so that they are aligned in the stacking direction, the plurality of ceramic green sheets 3 and 4 are stacked alternately. Then, a pressing process is performed to provide a mother stack for the plurality of chips 1.

The mother laminate is then cut along the cut lines 8 and 9 indicated by the dash-dotted lines, whereby a plurality of chips 1 for the individual laminated ceramic capacitors are obtained. The chip 1 is then fired, and by applying external electrodes to both ends of the chip 1,
It is a desired monolithic ceramic capacitor.

[0005]

Among the monolithic ceramic capacitors obtained as described above, the ones whose electrical characteristics such as insulation resistance are not sufficiently satisfied must be reliably eliminated at the shipping stage. For example,
If the gap formed between the internal electrode 2 and the outer surface of the chip 1 is insufficient, or if the internal electrode 2 is exposed from the outer surface of the chip 1, a desired insulation resistance may not be obtained. In extreme cases, an electric short circuit may be caused.

The electrical characteristics such as insulation resistance are greatly influenced by the positional relationship between the cut line 8 and the internal electrode 2 shown in FIG. 7, for example. In FIG. 7, b is the internal electrode 2
Design cut line 8 for cutting parallel to the long side 5 of
Shows the distance between. This distance b can be set accurately in the cutting device. Further, d represents the minimum required gap from the long side 5 of the internal electrode 2 to the outer surface of the chip 1. Therefore, when cut by the cut line 8 shown by the alternate long and short dash line, satisfactory characteristics with respect to insulation resistance are obtained. On the other hand, when the cutting is performed along the cut line 8a shown by the chain double-dashed line, the above-mentioned required minimum gap d is not ensured, and satisfactory characteristics regarding the insulation resistance cannot be obtained.

Even when cut by the cut line 8a, the internal electrode 2 is never exposed from the outer surface of the chip 1, so that it may initially have a sufficient insulation resistance. . However, after the laminated ceramic capacitor is mounted, it may be placed in high humidity while being continuously used, and the insulation resistance characteristics may deteriorate. The above-mentioned required minimum gap d is selected so that a satisfactory insulation resistance can be maintained even under such a condition.

If the cut line 8a is displaced to such an extent that the internal electrode 2 is exposed from the outer surface of the chip 1, this may be found by visually observing the external appearance of the chip 1. For example, if the metal forming the internal electrode 2 is a noble metal, the internal electrode 2 is also exposed because the internal electrode 2 is also plated in the plating performed when the external electrode is formed thereafter. Easy to distinguish. On the other hand, when the metal forming the internal electrode 2 is a base metal,
The exposed internal electrode 2 is oxidized during the process of forming the external electrode, plating is not applied, and
Since it has a color tone similar to that of ceramics, it is extremely difficult to distinguish.

In any case, it is relatively difficult to detect the inadequacy of the position of the internal electrode 2 reliably and efficiently, and to eliminate the monolithic ceramic capacitor having unsatisfactory insulation resistance characteristics with high reliability. Is. Such an improper position of the internal electrode 2 may be caused by, for example, displacement of the internal electrode 2 in the stacking process or pressing process of the ceramic green sheets 3 and 4, deflection of the cut surface in the cutting process, and the like. Then, with the recent progress in miniaturization and high capacity of multilayer ceramic capacitors, since the area of the internal electrode 2 is made as large as possible, the gap tends to be narrowed, and as a result, the position of the internal electrode 2 becomes incorrect. The probability of gaining will also be increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a monolithic ceramic capacitor which enables highly reliable and efficient determination of the position of the internal electrode.

[0011]

The present invention provides a plurality of ceramic green sheets in which a plurality of internal electrodes having long sides and short sides are formed by orienting the respective long sides and short sides in the same direction. And one internal electrode commonly faces each two adjacent internal electrodes in the long side direction via the ceramic green sheet, and between each two internal electrodes adjacent in the short side direction. A plurality of ceramic green sheets are stacked and pressed with the defined strip-shaped electrode-free portions aligned in the stacking direction, thereby obtaining a mother laminated body for a plurality of laminated ceramic capacitors. And a step of obtaining a plurality of chips for individual monolithic ceramic capacitors by cutting the mother laminated body. It is one that is directed to a process for the preparation of ceramic capacitors, in order to solve the technical problems described above, is characterized in that it comprises the following configuration.

That is, according to the present invention, in the step of preparing the ceramic green sheet, the conductive material that extends parallel to the long side of the internal electrode in the strip-shaped electrode absent portion and is located at a predetermined distance from the internal electrode. It is characterized in that such a ceramic green sheet having a sex deviation detection pattern is prepared. In the present invention, preferably, the distance a between the displacement detection pattern and the internal electrode is a = b- (c + d) (where, b is a designed cut line for cutting parallel to the long side of the internal electrode). , C is the dimension of the internal electrode in the short side direction, and d is the minimum required gap from the long side of the internal electrode to the outer surface of the chip.).

Further, the present invention is more advantageously applied when the internal electrodes contain a base metal.

[0014]

In the present invention, if the cut line is located on the deviation detection pattern, the position of the internal electrode is incorrect. If the cut line is located on the deviation detection pattern, it means that there is a deviation detection pattern in the chip.This deviation detection pattern short-circuits the external electrodes, so by measuring the resistance between the external electrodes, the internal Inappropriate electrode positions can be grasped as a short-circuited state.

[0015]

As described above, according to the present invention, the suitability of the position of the internal electrode can be reliably and efficiently determined even when the internal electrode cannot be clearly or completely seen from the outside. Therefore, it is possible to eliminate with high reliability a monolithic ceramic capacitor that causes defective insulation resistance characteristics.

As described above, when the distance a between the displacement detection pattern and the internal electrode is selected to be a = b- (c + d), the cut line is obtained when the required minimum gap d is secured. Does not pass through the shift detection pattern, and the cut line passes through the shift detection pattern only when the required minimum gap d is not ensured, so that the accuracy of determining the suitability of the position of the internal electrode can be further increased.

When the present invention is applied to a monolithic ceramic capacitor having internal electrodes containing a base metal,
Even if such an internal electrode is exposed from the outer surface of the chip, it is difficult to visually confirm it, so that the significance of the deviation detection pattern is particularly important.

[0018]

1 is a plan view corresponding to FIG. 6, showing ceramic green sheets 11 and 12 prepared in a method for manufacturing a monolithic ceramic capacitor according to an embodiment of the present invention. These ceramic green sheets 11 and 12 are alternately stacked to obtain a mother laminate for a plurality of laminated ceramic capacitors.

Ceramic green sheets 11 and 12
A plurality of internal electrodes 13 are formed on each. Each of the plurality of internal electrodes 13 has a long side 14 and a short side 15, and the long sides 14 and the short sides 15 are oriented in the same direction. In addition, a strip-shaped electrode absent portion 16 is located between each two internal electrodes 13 adjacent to each other in the direction of the short side 15.

When these ceramic green sheets 11 and 12 are alternately stacked, the following state is obtained. First, as in the case of the ceramic green sheets 3 and 4 shown in FIG. 6, one internal electrode 13 is provided for each two internal electrodes 13 adjacent in the direction of the long side 14 via a certain ceramic green sheet 11 or 12. Are facing each other in common. Further, the strip-shaped electrode nonexisting portions 16 defined between the two internal electrodes 13 adjacent to each other in the short side 15 direction of the ceramic green sheet 11 are aligned so as to be aligned in the stacking direction.

In addition to the above-mentioned internal electrode 13, on the ceramic green sheets 11 and 12, the strip-shaped electrode-free portion 16 extends in parallel with the long side 14 of the internal electrode 13 and has a predetermined distance from the internal electrode 13. The conductive misregistration detection pattern 17 is formed at a distance a (see FIG. 2). The shift detection pattern 17 is preferably formed simultaneously with the internal electrode 13 by printing, for example. As a result, the deviation detection pattern 17 and the internal electrode 1
This is because a fixed positional relationship with 3 is guaranteed.

The plurality of ceramic green sheets 11 and 12 stacked in the above-described state are then pressed to provide a mother laminate.
The mother laminate is then cut along cut lines 18 and 19. As a result, a plurality of chips 21 for individual monolithic ceramic capacitors 20 as shown in FIG. 3 are obtained. The chip 21 is then fired, and external electrodes 22 and 23 are applied to both ends of the chip 21 so that the desired multilayer ceramic capacitor 20 is obtained.
Is obtained.

FIG. 2 shows a ceramic green sheet 11
Alternatively, a part of 12 is shown enlarged. With reference to FIG. 2, a preferable positional relationship between the internal electrodes 13 and the displacement detection pattern 17 will be described. Deviation detection pattern 17
The distance a between the internal electrode 13 and the internal electrode 13 is preferably selected so that a = b- (c + d). Here, b is a designed cut line 1 for cutting parallel to the long side 14 of the internal electrode 13.
8 is a distance between them, c is a dimension of the internal electrode 13 in the direction of the short side 15, and d is a required minimum gap from the long side 14 of the internal electrode 13 to the outer surface of the chip 21.

By selecting the distance a as described above, the cut line 18 is not positioned on the deviation detection pattern 17 while the position of the cut line 18 is proper and the necessary minimum gap d is secured. Therefore, as shown in FIG. 3, it is assured that the chip 21 having the proper position of the internal electrode 13 is obtained. On the other hand, like the cut line 18a shown by the chain double-dashed line in FIG.
Is located on the misregistration detection pattern 17, and as shown in FIG. 4, at least a part of the misregistration detection pattern 17 is taken into the chip 21. As described above, when the displacement detection pattern 17 exists in the chip 21, the displacement detection pattern 17 short-circuits the pair of external electrodes 22 and 23, and the resistance between the external electrodes 22 and 23 is measured. Immediately and reliably, it is possible to detect that the position of the internal electrode 13 is incorrect.

It should be noted that the width of the displacement detection pattern 17 is sufficient to ensure conductivity. For example, the width of the deviation detection pattern 17 is about 5 μm. Although the present invention has been described above with reference to the preferred embodiments, various other modifications are possible within the scope of the present invention. For example, in the illustrated embodiment, the shift detection pattern 1
7 was formed on all electrode-free portions 16, but 1
The shift detection pattern may be formed for each or several electrode-free portions.

[Brief description of drawings]

FIG. 1 is a plan view showing ceramic green sheets 11 and 12 prepared in a method for manufacturing a monolithic ceramic capacitor according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view showing a part of the ceramic green sheet 11 or 12 shown in FIG.

FIG. 3 is a plan sectional view showing a monolithic ceramic capacitor 20 including a chip 21 appropriately manufactured by using the ceramic green sheets 11 and 12 shown in FIG.

4 is a plan sectional view corresponding to FIG. 3 and showing a multilayer ceramic capacitor 20 including a chip 21 improperly manufactured using the ceramic green sheets 11 and 12 shown in FIG. 1. FIG.

FIG. 5 is a longitudinal sectional view showing a chip 1 for a laminated ceramic capacitor which is of interest to the present invention.

6 is a view corresponding to FIG. 1, and is a ceramic green sheet 3 prepared to obtain the chip 1 shown in FIG.
It is a top view which shows and 4.

7 is a plan view corresponding to FIG. 2 and showing a part of the ceramic green sheet 3 or 4 shown in FIG. 6 in an enlarged manner.

[Explanation of symbols]

 11, 12 Ceramic green sheet 13 Internal electrode 14 Long side 15 Short side 16 Electrode non-existing part 17 Displacement detection pattern 18, 18a, 19 Cut line 20 Multilayer ceramic capacitor 21 Chip 22, 23 External electrode

Claims (3)

[Claims] 1. A plurality of ceramic green sheets each having a plurality of internal electrodes having long sides and short sides formed by orienting the respective long sides and short sides in the same direction are provided, and the ceramic green sheets are interposed therebetween. One of the internal electrodes is commonly opposed to each of the two internal electrodes adjacent to each other in the long side direction, and two internal electrodes are adjacent to each other in the short side direction.
A plurality of ceramic green sheets are stacked and pressed in a state where the strip-shaped electrode-absent portions defined between the two internal electrodes are aligned so as to be aligned in the stacking direction. In order to obtain a mother laminated body for obtaining a plurality of chips for individual laminated ceramic capacitors by cutting the mother laminated body, the method includes the steps of: In the step of forming a conductive deviation detection pattern that extends in parallel with the long side of the internal electrode in the strip-shaped electrode absent portion and is located at a predetermined distance from the internal electrode, Such a ceramic green sheet is prepared. Method of manufacturing the capacitor. 2. The distance a between the displacement detection pattern and the internal electrode is a = b- (c + d) (where, b is the distance between designed cut lines for cutting parallel to the long side of the internal electrode). , C is a dimension in the short side direction of the internal electrode, and d is a required minimum gap from the long side of the internal electrode to the outer surface of the chip.) Of the multilayer ceramic capacitor according to claim 1. Production method. 3. The method of manufacturing a monolithic ceramic capacitor according to claim 1, wherein the internal electrode contains a base metal.