JP2002353068A - Multilayer capacitor and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the drop of reliability due to structural defects, and accelerate the drop of equivalent series resistance, by arranging the form of a product into a rectangular parallelepiped, without dropping the capacitance. SOLUTION: A stacked capacitor 10 is composed of a dielectric layer 11, a first inner electrode layer 12, a second inner electrode layer 13, and an outer electrode 14. The section where the inner electrode layer is made is divided into a section 15, where the inner electrodes come closest to each other and a section 16, where the inner electrodes do not come closest to each other. The thickness of the inner electrode 15, where the inner electrodes do not come closest to each other is larger than the thickness of the inner electrode in the section 16, where the inner electrodes come closest to each other. It is desirable that the thickness of the second inner electrode layer 13 be exactly equal to the thickness of the first inner electrode layer 12, and it is desirable that it be stacked on the section 15, where the inner electrodes do not come closest to each other. The thickness of the electrode of the inner electrode part 16 to form a capacitor is set to be larger than 1.2 μm and smaller than 3.0 μm, and the thickness of the electrode of the inner electrode 16 do not to form a capacitor which is larger than 2.4 μm (twice as large as it is) and smaller than 6.0 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a multilayer capacitor formed by alternately stacking internal electrode layers and dielectric layers and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a multilayer capacitor has a structure in which an internal electrode 22 having the same thickness is sandwiched between dielectrics 21 as shown in FIG.
Are alternately shifted from each other. In the case of such a conventional multilayer capacitor, when the lamination is repeated a number of times in order to realize a high capacitance, the volume of the portion 24 where the internal electrode is not closest is reduced due to the manufacturing process. Therefore, the external shape of the capacitor did not become a well-formed rectangular parallelepiped.

[0003] The reason is that the relationship between the number m of electrodes used for the portion 25 where the internal electrode is closest and the number n of electrodes used for the portion 24 where the internal electrode is not closest is m = 2n-
The number n of electrodes used for the portion 24 to which the internal electrode is not closest is mainly smaller than the number m of electrodes used for the portion 25 to which the internal electrode is closest, because it is one of 1, 2n, and 2n + 1. No.

Since the number n of electrodes used in the portion 24 where the internal electrode is not closest is smaller than the number m of electrodes used in the portion 25 where the internal electrode is closest, the dielectric 21
During the process of press-bonding the internal electrode 22 and the internal electrode 22, the pressure applied to the portion 24 where the internal electrode is not in closest contact decreases.
As a result, when high lamination is performed in the portion 24 where the internal electrode is not in closest contact, adhesion between the internal electrode layer 22 and the dielectric layer 21 is not obtained, and structural defects such as delamination occur inside the multilayer capacitor after firing. Had become.
These structural defects are one factor that greatly threatens the reliability of the multilayer capacitor.

[0005] Techniques for solving this problem include:
By applying isotropic pressure to the entire laminate 20,
There is a hydrostatic pressing method in which the adhesion between the internal electrode layer 22 and the dielectric layer 21 is enhanced. However, this method is very inadequate for practical use because it requires a large cost for introducing equipment and a long time for manufacturing a multilayer capacitor.

As a countermeasure against the above-mentioned problem, Japanese Unexamined Utility Model Publication No. Sho 60-49621 discloses an internal electrode in which the thickness of a lead-out portion is increased from 1.3 times to 3.0 times the thickness of a portion contributing to capacity development. Is described.
However, the thickness of the part contributing to the capacity development of the internal electrode is 3.0
At the time of μm, the thickness of the drawer portion is 4.0 μm to 9.0 μm, which is much larger than the current product. That is, the recent demand for thinning the electrode portion has not been sufficiently satisfied.

Further, Japanese Unexamined Patent Application Publication No. 9-69463 discloses a technique for solving the problem of delamination, which is a problem when an internal electrode is formed into a thin film / multilayer, and is disclosed in Japanese Utility Model Laid-Open Publication No. 60-49621. Using such a structure, the thickness of the capacitor electrode portion contributing to capacitance development is set to 0.4 μm to 1.2 μm, and the thickness of the extraction electrode portion is set to 0.8 μm to 2.0 μm. However, the thickness of the capacitor electrode is 0.4 μm
If it is manufactured to have a thickness of about 1.2 μm, the ESR will increase dramatically because the thickness of the capacitor electrode portion is small.

[0008]

In the structure of a conventional multilayer capacitor, defects (shorts, cracks) due to structural defects such as delamination frequently occur because of the number of electrodes used in the portion 24 where the internal electrode is not closest. Is smaller than the number of electrodes used for the portion 25 to which the internal electrode is closest, so that the volume of the portion 24 to which the internal electrode is not closest is smaller than the volume of the portion 25 to which the internal electrode is closest.

As described above, in the conventional technology, it is difficult to make the external shape of the multilayer capacitor a rectangular parallelepiped, and the reliability is not sufficient due to the occurrence of structural defects such as delamination. there were.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a structure and a structure for preventing a decrease in reliability due to a structural defect in a multilayer capacitor without changing (dropping) the capacitance of the product and arranging the product shape. It is intended to provide a manufacturing method.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a multilayer capacitor formed by alternately stacking dielectrics and internal electrodes, wherein the internal electrodes are closest to each other in the stacking direction. The internal electrode thickness of the part that does not
It is characterized in that it is larger than the thickness of the internal electrode at the closest part. In particular, it is desirable that the thickness of the internal electrode at the portion where the internal electrode is closest is larger than 1.2 μm and less than 3.0 μm, and the thickness of the internal electrode at the portion where the internal electrode is not closest is larger than 2.4 μm and less than 6.0 μm.

The following seven methods are proposed as a method for manufacturing the laminate.

The first manufacturing method comprises the steps of thermocompression bonding a sheet having a dielectric film applied and formed on a support film onto a support plate, and forming a sheet having a first internal electrode layer formed on the support film by patterning. A step 2 of thermocompression bonding on the thermocompression-bonded dielectric layer, and a sheet on which a second internal electrode layer is pattern-formed on a support film, and the thermocompression-bonded first internal electrode layer is aligned. Step 3 of thermocompression bonding on the
A manufacturing method characterized by sequentially repeating steps 1 to 3 and finally performing step 1 to obtain a laminate.

The second manufacturing method comprises the steps of thermocompression bonding a sheet having a dielectric film formed thereon on a support film onto a support plate, and forming a pattern of a second internal electrode layer on the support film. Step 2 of obtaining a pattern-formed internal electrode sheet by aligning the first internal electrode layer, and aligning the internal electrode sheet obtained in Step 2 and thermocompressing the thermocompression-bonded dielectric layer on the dielectric layer. And a step 3 in which the steps 1 to 3 are sequentially repeated, and finally the step 1 is performed to obtain a laminate.

The third manufacturing method comprises the steps of thermocompression bonding a sheet having a dielectric film formed on a support film onto a support plate, and a first internal electrode layer and a second internal electrode on the support film. Step 2 of forming an internal electrode sheet by simultaneously patterning the layers, and Step 3 of thermocompression bonding the internal electrode sheet obtained in Step 2 on the thermocompression-bonded dielectric layer. Step 3 is sequentially repeated, and finally the above step
1 is a production method characterized in that a laminate is obtained by performing 1.

The fourth manufacturing method comprises a step 1 of thermocompression bonding a sheet on which a dielectric layer is formed on a support film, on a support plate, and a step of forming a first layer on the dielectric layer, which is formed on the support film by coating. Step 2 of patterning the internal electrode layer, and Step 3 of aligning and patterning the second internal electrode layer on the first internal electrode layer to obtain a dielectric sheet having the internal electrode layer, Step 4 of thermocompression-bonding the dielectric sheet provided with the internal electrode layer obtained in the step 3 on the thermocompression-bonded dielectric layer. 4. A manufacturing method characterized by repeatedly performing step 4 to obtain a laminate.

The fifth manufacturing method includes a step 1 of thermocompression bonding a sheet on which a dielectric layer is formed on a support film on a support plate; Patterning an internal electrode layer and a second internal electrode layer simultaneously to obtain a dielectric sheet having an internal electrode layer; and forming the internal electrode obtained in step 2 on the thermocompression-bonded dielectric layer. Step 3 of thermocompression-bonding the dielectric sheet provided with a layer. After performing Step 1, perform Step 2 and Step 3.
3. A production method characterized by repeatedly performing step 3 to obtain a laminate.

The sixth manufacturing method comprises a step 1 of forming a pattern of a first internal electrode layer on a supporting film and a step of forming a pattern by aligning a second internal electrode layer on the first internal electrode layer. Performing a step 2; applying and forming a dielectric layer on the first internal electrode layer and the second internal electrode layer to obtain a dielectric sheet having the internal electrode layer; The method includes a step 4 of thermocompression bonding the dielectric sheet obtained in the step 3, and a step 5 of thermocompression bonding of a sheet having a dielectric layer applied and formed on a support film. After repeating the steps 1 to 4, Performing a step 5 to obtain a laminate.

The seventh manufacturing method includes a step 1 of aligning a first internal electrode layer and a second internal electrode layer on a support film and simultaneously forming a pattern, and a step 1 Step 2 of coating a dielectric layer on the internal electrode layer to obtain a dielectric sheet having the internal electrode layer, and Step 3 of thermocompression bonding the dielectric sheet obtained in Step 2 on a support plate
And a step 4 of thermocompression bonding a sheet on which a dielectric layer is formed on a support film.The steps 1 to 3 are sequentially repeated, and finally, the step 4 is performed to obtain a laminate. This is a characteristic manufacturing method.

The laminate manufactured by any one of the above seven manufacturing methods is subjected to unit-by-unit unit so that the internal electrode layer on the cut surface is the internal electrode layer at the portion where the internal electrode layers are closest to each other. Then, an external electrode is applied so as to be electrically connected to the internal electrode, and then fired to manufacture a multilayer capacitor.

In this case, in the third, fifth, and seventh methods of manufacturing a laminate, the internal electrode layer is formed by a screen printing method, and the aperture ratio per unit area of the screen or the thickness of the gauze is changed. In this way, the discharge amount of the electrode paste at a desired screen discharge position is controlled, and an internal electrode layer having a different thickness depending on the discharge position is formed by one screen printing.

[0022]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(Embodiment 1) In this embodiment, a structure of a multilayer capacitor according to the present invention corresponding to claim 1 will be described.

First, a conventional multilayer capacitor will be described. As shown in FIG. 2, a multilayer capacitor 20 having a conventional structure includes a dielectric layer 21 made of ceramic or the like, an internal electrode layer 22, and an external electrode 23. It is divided into a portion 24 where the electrode is not closest and a portion 25 where the internal electrode is closest.

A method of manufacturing the conventional multilayer capacitor 20 will be described below. The step of thermocompression-bonding a sheet on which a dielectric layer 21 is formed on a support film to a support plate is referred to as a step 1. The sheet on which a pattern of the internal electrode layer 22 is formed on the support film is formed on the thermocompression-bonded dielectric layer. Assuming that step 2 is thermocompression bonding, steps 1 and 2 are sequentially repeated, and finally step 1 is performed to produce a laminate. After that, the manufactured laminate is cut into a desired unit structure, an external electrode is applied and fired, thereby completing the multilayer capacitor 20 having the conventional structure.

At this time, the number m of electrodes used for the portion 25 where the internal electrode is closest, and the portion 24 where the internal electrode is not closest.
Is n = 2n-1, 2n, 2
Since it is any one of n + 1, the number n of electrodes used in the portion 24 where the internal electrode is not closest is smaller than the number m of electrodes used in the portion 25 where the internal electrode is closest.
When the lamination is repeated many times in order to realize high capacitance, the volume of the portion 24 where the internal electrode is not closest is smaller than the volume of the portion 25 where the internal electrode is closest. It does not form a rectangular parallelepiped with a regular outer shape, and this causes structural defects such as delamination.

On the other hand, as shown in FIG. 1, the multilayer capacitor 10 of the present invention has a dielectric layer 11, a first internal electrode layer 12, and a second internal electrode layer 13 made of a sintered body such as ceramic.
And an external electrode 14. In FIG. 1, the stacked body is divided into a portion 15 where the internal electrodes are not closest to each other in the stacking direction and a portion 16 where the internal electrodes are closest to each other in the main surface direction of the stack. In FIG. 1, the close arrangement pitch in the stacking direction is about 2: 1 between the portion 15 that is not closest and the portion 16 that is closest. The second internal electrode layer 13 is formed on the first internal electrode layer 12 by the section 15
Are the internal electrode layers laminated. As described above, in the present embodiment, in order to solve the above-described problem in the multilayer capacitor 20 having the conventional structure, the thickness of the internal electrode (the first internal electrode layer 12 + the thickness of the second internal electrode layer 13) corresponds to the portion 16 where the internal electrode is closest.
The feature is that the structure is larger (thicker) than the thickness of the internal electrode (thickness of the first internal electrode layer 12). In particular,
The thickness of the internal electrode at the portion where the internal electrode is closest is greater than 1.2 μm and less than 3.0 μm, and the thickness of the internal electrode at the portion where the internal electrode is not closest is twice as thick as 2.4 μm.
Desirably, it is less than 0 μm.

In order to realize this structure, the thickness of the second internal electrode layer 13 is desirably exactly equal to the thickness of the first internal electrode layer 12 in the laminating process. Is preferably laminated on the portion 15 where the internal electrode is not closest. Then, the multilayer capacitor 1 of the present invention
Embodiment 2 described below is a method of manufacturing
Sample preparation was performed using (corresponding to claim 4) and Embodiment 9 (corresponding to claim 11). However, in the portion where the above-mentioned second internal electrode layer 13 is laminated and laminated,
The present invention is not limited to the case where the effects of the present invention are impaired by producing a multilayer capacitor, and the thickness and the laminated portion may be changed.

(Embodiment 2) In this embodiment, a method for manufacturing a multilayer capacitor according to the present invention corresponding to claim 4 will be described with reference to FIG.

As a manufacturing procedure, a sheet in which a dielectric layer 32 is applied and formed on a support film 31 is thermocompression-bonded on a support plate 35 (step 1), and a first internal electrode layer 33 is formed on the support film 37. The patterned sheet is thermocompression-bonded on the thermocompression-bonded dielectric layer 32 (step 2), and the sheet on which the second internal electrode layer 34 is patterned on the support film 38 is aligned. The thermocompression bonding is performed on the thermocompression-bonded first internal electrode layer 33 (step 3).

After these steps 1 to 3 are sequentially repeated, step 1 is finally performed to manufacture a laminate 36.

The multilayer capacitor 10 of the present invention can be manufactured by a manufacturing method characterized by such a manufacturing procedure.

The multilayer capacitor of the present invention cuts (cuts) each unit unit at a portion of a dotted line drawn in the vertical direction in the laminated body 36 of FIG. 3, and in each cut unit unit, External electrodes are applied to the outer periphery of the laminate so as to be electrically connected to the internal electrodes, respectively, and are fired.

(Embodiment 3) In this embodiment, a method for manufacturing a multilayer capacitor according to the present invention will be described with reference to FIG.

As a manufacturing procedure, a sheet formed by coating a dielectric layer 42 on a support film 41 is thermocompression-bonded on a support plate 45 (step 1), and a second internal electrode layer 44 is patterned on the support film 46 by patterning. Formed and then the first internal electrode layer 43
Are aligned to produce a patterned internal electrode sheet (Step 2), and the internal electrode sheet produced in Step 2 is aligned and thermocompressed onto the thermocompressed dielectric layer 42 (Step 3). .

After the steps 1 to 3 are sequentially repeated, the step 1 is finally performed to manufacture the laminate 47.

The multilayer capacitor 10 of the present invention can be manufactured by a manufacturing method characterized by such a manufacturing procedure.

The multilayer capacitor of the present invention cuts (cuts) each unit unit at a portion indicated by a dotted line drawn in the vertical direction in the multilayer body 47 of FIG. External electrodes are applied to the outer periphery of the laminate so as to be electrically connected to the internal electrodes, respectively, and are fired.

(Embodiment 4) In this embodiment, a method for manufacturing a multilayer capacitor according to the present invention will be described with reference to FIG.

As a manufacturing procedure, a sheet formed by coating a dielectric layer 52 on a support film 51 is thermocompression-bonded on a support plate 55 (step 1), and a first internal electrode layer 53 and a The two internal electrode layers 54 are simultaneously patterned to produce an internal electrode sheet (Step 2), and the internal electrode sheet produced in Step 2 is thermocompression-bonded on the thermocompression-bonded dielectric layer 52 (Step 3). .

After these steps 1 to 3 are sequentially repeated, step 1 is finally performed to manufacture a laminate 57.

The multilayer capacitor 10 of the present invention can be manufactured by a manufacturing method characterized by such a manufacturing procedure.

The multilayer capacitor of the present invention is cut (cut) into unit units at the dotted line portions drawn in the vertical direction in the multilayer body 57 of FIG. 5, and in each of the cut unit units, External electrodes are applied to the outer periphery of the laminate so as to be electrically connected to the internal electrodes, respectively, and are fired.

(Embodiment 5) In this embodiment, a method for manufacturing a multilayer capacitor according to the present invention corresponding to claim 7 will be described with reference to FIG.

As a manufacturing procedure, a sheet in which a dielectric layer 62 is applied and formed on a support film 61 is thermocompression-bonded on a support plate 65 (step 1), and the dielectric layer 62 is applied and formed on the support film 66. Then, a first internal electrode layer 63 is patterned (step 2), and a second internal electrode layer 64 is positioned and patterned on the first internal electrode layer 63 to form a dielectric having the internal electrode layer. A body sheet is manufactured (Step 3), and the dielectric sheet having the internal electrode layer manufactured in Step 3 is thermocompression-bonded on the thermocompression-bonded dielectric layer 62 (Step 4).

According to the above-described procedure, in the actual production, after the step 1 is performed, the steps 2 to 4 are repeated to produce the laminate 67.

The multilayer capacitor 10 of the present invention can be manufactured by a manufacturing method characterized by such a manufacturing procedure.

The multilayer capacitor of the present invention is cut (cut) in units of unit at the portion of the dotted line drawn in the vertical direction in the laminated body 67 of FIG. External electrodes are applied to the outer periphery of the laminate so as to be electrically connected to the internal electrodes, respectively, and are fired.

(Embodiment 6) In this embodiment, a method for manufacturing a multilayer capacitor according to the present invention will be described with reference to FIG.

As a manufacturing procedure, a sheet in which a dielectric layer 72 is applied and formed on a support film 71 is thermocompression-bonded to a support plate 75 (step 1), and a sheet is formed on the dielectric film 72 applied and formed on a support film 76. First, a first internal electrode layer 73 and a second internal electrode layer 74 are simultaneously patterned to produce a dielectric sheet having the internal electrode layer (Step 2), and the thermocompression-bonded dielectric layer 72 is formed. The dielectric sheet provided with the internal electrode layer manufactured in Step 2 is thermocompression-bonded (Step 3).

According to the above-described procedure, in the actual production, first, the step 1 is performed, and then the steps 2 and 3 are repeated to produce the laminate 77.

The multilayer capacitor 10 of the present invention can be manufactured by a manufacturing method characterized by such a manufacturing procedure.

The multilayer capacitor of the present invention cuts (cuts) each unit unit at a portion of a dotted line drawn in the vertical direction in the multilayer body 77 of FIG. 7, and in each cut unit unit, External electrodes are applied to the outer periphery of the laminate so as to be electrically connected to the internal electrodes, respectively, and are fired.

(Embodiment 7) In this embodiment, a method for manufacturing a multilayer capacitor according to the present invention will be described with reference to FIG.

As a manufacturing procedure, a first internal electrode layer 83 is patterned on the support film 81 (step 1), and a second internal electrode layer 84 is aligned on the first internal electrode layer 83. (Step 2), and a dielectric layer 82 is applied and formed on the first internal electrode layer 83 and the second internal electrode layer 84 to produce a dielectric sheet having the internal electrode layer ( Step 3) The dielectric sheet produced in Step 3 is thermocompression-bonded on the support plate 85 (Step 4), and the sheet on which the dielectric layer 82 is applied and formed on the support film 86 is thermocompression-bonded (Step 5).

According to the above-described procedure, in the actual production, after the steps 1 to 4 are repeated, the step 5 is performed to produce the laminate 87.

The multilayer capacitor 10 of the present invention can be manufactured by a manufacturing method characterized by such a manufacturing procedure.

The multilayer capacitor of the present invention cuts (cuts) each unit unit at a portion of a dotted line drawn in the vertical direction in the multilayer body 87 of FIG. 8, and in each cut unit unit, External electrodes are applied to the outer periphery of the laminate so as to be electrically connected to the internal electrodes, respectively, and are fired.

(Embodiment 8) In this embodiment, a method of manufacturing a multilayer capacitor according to the present invention will be described with reference to FIG.

As a manufacturing procedure, the first internal electrode layer 93 and the second internal electrode layer 94 are aligned and formed on the support film 91 at the same time (step 1). A dielectric layer 92 is formed by coating a dielectric layer 92 on the second internal electrode layer 94 to produce a dielectric sheet having the internal electrode layer (step 2). The sheet having the dielectric layer 92 applied and formed on the support film 96 is thermocompressed (step 4).

According to the above procedure, in the actual production, after the steps 1 to 3 are sequentially repeated, finally, the step 4 is carried out to produce the laminate 97.

The multilayer capacitor 10 of the present invention can be manufactured by a manufacturing method characterized by such a manufacturing procedure.

The multilayer capacitor of the present invention cuts (cuts) each unit unit at a portion indicated by a dotted line drawn in the vertical direction in the multilayer body 97 of FIG. 9, and in each cut unit unit, External electrodes are applied to the outer periphery of the laminate so as to be electrically connected to the internal electrodes, respectively, and are fired.

(Embodiment 9) In this embodiment, a method for manufacturing a multilayer capacitor according to the present invention will be described with reference to FIG.

The second to eighth embodiments described above.
When viewed from the upper surface direction of the layer, the laminate manufactured by the manufacturing method described in any one of the above is as shown in the upper diagram of FIG. In FIG. 10, the dielectric formed on the uppermost surface of the stacked body is described as seen through from above, in order to facilitate understanding of the formation and arrangement relationship of each unit.

The three-dimensional laminated sheet formed and arranged as described above is cut (cut) vertically and horizontally along the dashed line 101 shown in FIG. 10, and the outer periphery of the cut unit unit laminated body is cut. As shown in FIG. 10, the positive and negative external electrodes 14 are applied to the surface, and the applied laminate is fired to obtain one unit of the multilayer capacitor 10.

(Embodiment 10) In this embodiment, a method of manufacturing a multilayer capacitor according to claim 12 will be described with reference to FIG.

In the present embodiment, the internal electrode layer is formed by using a screen printing method. By changing the aperture ratio 114 or the gauze thickness 115 per unit area of the screen 111, the electrode paste discharge amount 112 at a desired screen discharge position is controlled. If you do this,
With one screen printing, the internal electrode layer 113 having a different thickness depending on the discharge position of the screen can be formed. That is, the first internal electrode layer 1 in FIG.
The second and second internal electrode layers 13 can be simultaneously patterned. In the example of FIG. 11, since the aperture ratio at the center of the screen 111 is large, the thickness of the internal electrode layer at the center can be increased.

Such screen printing can be used when manufacturing the multilayer capacitor according to any one of the third, fifth, and seventh embodiments.

[0070]

(Embodiment 1) In this embodiment, in the multilayer capacitor 10 of the present invention and the multilayer capacitor 20 of the conventional structure, the number of samples which caused defects (shorts, cracks) due to structural defects per 1000 pieces was measured. did.

In the present embodiment, a multilayer capacitor was experimentally manufactured by the following method.

Each dielectric sheet (dielectric layer) 11, 21
Was formed by a method of coating a slurry on a support film using a composition mainly composed of barium titanate having an average particle diameter of 0.3 μm, a butyral binder and a phthalate plasticizer.

The first internal electrode layer 12, the second internal electrode layer 13, and the internal electrode layer 22 are made of a paste containing nickel powder having an average particle diameter of 0.4 μm as a main raw material.
0 (FIG. 11), the internal electrode layers were each formed to a thickness of 2.0 μm by the screen printing method of the method shown in FIG. In order to realize the structure of the present invention, it is desirable that the thickness of the second internal electrode layer 13 is completely equal to the thickness of the first internal electrode layer 12 in the lamination process. As described above, in the present embodiment, the portion which is not closest (1 in FIG. 1)
5) (the thickness of the first internal electrode layer +
The thickness of the second internal electrode layer was 2.0 μm × 2 = 4.0 μm.

Thereafter, the multilayer capacitor 10 of this embodiment is manufactured using the manufacturing method according to the second embodiment (corresponding to claim 4) and the ninth embodiment (corresponding to claim 11) shown in FIG. A multilayer capacitor was manufactured. Regarding the multilayer capacitor 20 having the conventional structure, the multilayer capacitor was manufactured by the manufacturing method for the conventional structure described in the description of the first embodiment.

Each of these two types of multilayer capacitors was manufactured in a quantity of 1,000 pieces, and the results of examination were made after confirming the generation probability of defects (shorts, cracks) due to structural defects (Table 1).
Shown in

[0076]

[Table 1]

While the defect generation probability was 5.2% in the conventional structure, it was 0.1% in the structure of the present embodiment, and the defect due to the structural defect was reduced to about 1/50 of the conventional structure.

From these results, it is understood that the probability of generating structural defects can be significantly reduced by adopting the structure of the multilayer capacitor of the present invention.

(Embodiment 2) In this embodiment, as a product shape, a so-called 13 type (length 3.2 mm × thickness 1.15 mm × width)
(1.6 mm) A multilayer capacitor having 300 dielectric layers was manufactured, and an investigation was made on the shape of the manufactured product.

As shown in FIG. 2, the external dimensions of the multilayer capacitor having the conventional structure manufactured by the manufacturing method of the conventional structure described in the first embodiment have a length 26 and a central portion of the portion 25 where the internal electrode is closest. , A thickness 27b at a connection portion between the external electrode 23 and the internal electrode 22,
The width is 28.

On the other hand, as shown in FIG. 1, the external dimensions of the multilayer capacitor of the present invention manufactured by the manufacturing method of the first embodiment are the length 17 and the thickness at the center of the portion 16 where the internal electrode is closest. The dimension 18a is the thickness 18b and the width 19 at the connection between the external electrode 14 and the internal electrodes 12, 13.

[0086] 1000 multilayer capacitors of the conventional structure
The external dimensions of 1000 multilayer capacitors of this example were measured in length, thickness, and width, respectively, and the average was calculated. The results are shown in Table 2.

[0083]

[Table 2]

According to Table 2, the length 26 of the conventional structure is reduced by about 0.1% compared to the length 17 of the multilayer capacitor of the present invention, and the width of the multilayer capacitor of the present invention is reduced by about 0.1%. The width 28 of the conventional structure is about
Only a 0.2% decrease. When the thickness 27a of the conventional structure is compared with the thickness 18a of the multilayer capacitor of the present invention, a decrease of about 0.1% can be seen. However, since these are within the error range, they are notable due to the difference between the two structures. It can be said that no significant difference occurred.

However, when the thickness 27b of the conventional structure is compared with the thickness 27a of the conventional structure, about 44.0%
The fact is that when the lamination is repeated many times to achieve high capacitance, the volume of the portion 24 where the internal electrode is not closest is smaller than the volume of the portion 25 where the internal electrode is closest. For this reason, it is shown that the external shape of the capacitor did not become a rectangular parallelepiped.

On the other hand, the thickness 18a of the multilayer capacitor of the present invention is compared with the thickness 18a of the multilayer capacitor of the present invention.
Compared to b, there was only a 1.3% reduction. this is,
The problem to be solved by the present invention, "the volume difference caused by the difference in the number of internal electrodes" is sufficiently solved.

From these results, it can be said that the structure of the multilayer capacitor of the present invention is much closer to a rectangular parallelepiped than the structure of the conventional multilayer capacitor.

(Embodiment 3) In this embodiment, an investigation was made on the equivalent series resistance (ESR) of the multilayer capacitor.

Equivalent series resistance (ESR) of multilayer capacitor
Depends on the equivalent series resistance of the internal electrodes. Embodiment 1
As described in the description, the multilayer capacitor 10 of the present invention
In the portion 15 where the internal electrode is not closest, the second internal electrode layer 13 is superimposed on the first internal electrode layer 12 so that the equivalent series resistance (E
SR) is compared with that of the multilayer capacitor 20 having the conventional structure by comparing the applied frequency characteristics of the equivalent series resistance. FIG. 12 shows the result.

FIG. 12 shows that the multilayer capacitor 1 of this embodiment is
It can be seen that the equivalent series resistance value is smaller at 0.
The reason is that the electrode portion is increased by the thickness of the second internal electrode 13 by overlapping the second internal electrode 13 on the first internal electrode 12.

Since the structure of the multilayer capacitor of the present invention is an element exhibiting the above-described effects, even if the multilayer capacitor is made of an electrode sheet using Ag, the above-described manufacturing method of the present invention will As long as the structure can be realized, there is no limitation on the materials to be used and the obtained measured values.

Example 4 In this example, a multilayer capacitor having 300 dielectric layers was manufactured to investigate the product capacity.

The capacitance of each of the 1000 multilayer capacitors having the conventional structure and the 1000 multilayer capacitors of the present invention was measured, and the average value was obtained.

As a result, the conventional multilayer capacitor 20
The average capacitance was 1.08 mC, whereas the multilayer capacitor 10 of this example had an average capacitance of 1.10 mC, and the difference was less than 2%. From the above, it can be said that there was no large change in the capacitance between the two.

The embodiments of the present invention have been described above. In Examples 1, 2, 3, and 4, Embodiment 2 (corresponding to Claim 4) and Embodiment 9 (corresponding to Claim 1).
Although the multilayer capacitor was manufactured by the manufacturing method described in Embodiment 1), the manufacturing method described in Embodiments 3 to 8 (corresponding to claims 5 to 10) and Embodiment 10 (corresponding to claim 12) was used. Also obtained similar results.

Example 5 In this example, an investigation was made on the effect of the difference in the thickness of the internal electrodes on the electrical characteristics.

In the fifth embodiment, the thickness of the internal electrode layer 12 is
The multilayer capacitor of the present invention was manufactured by the manufacturing method of Example 1 at 0.8 μm. This capacitor has 10MHZ
The equivalent series resistance (ESR) at z was measured to be 0.084Ω. On the other hand, when the ESR of the multilayer capacitor of the present invention manufactured by the manufacturing method of Example 1 in which the thickness of the internal electrode layer 12 was 2.0 μm was 0.026Ω. When these two are compared, the resistance of 0.8 μm is about three times higher than that of 2.0 μm. Therefore, as can be seen from this embodiment, in the multilayer capacitor having the structure of the present invention in which the thickness of the internal electrode layer is 0.8 μm, the equivalent series resistance (ES
R) rises, which significantly impairs the effects of the present invention, and is therefore unsuitable. If the thickness of the internal electrode layer is larger than 1.2 μm as in this embodiment, the ESR can be suppressed low, which is preferable in terms of characteristics.

Next, with the thickness of the internal electrode layer being 3.5 μm,
The multilayer capacitor of the present invention was manufactured by the manufacturing method of the first embodiment. This capacitor has an average capacitance of 0.98
mC. On the other hand, the multilayer capacitor 10 of Example 4 had an average capacitance of 1.10 mC, and the difference between them was about 11%. Thus, the thickness of the internal electrode layer is set to 3.
When the thickness is 5 μm, a remarkable decrease in the capacitance is observed, so that the effect of the present invention is significantly impaired. As in the present embodiment, if the thickness of the internal electrode layer is smaller than 3.0 μm, the capacitance can be increased, which is preferable in terms of characteristics.

From the above embodiments, in order to solve all the problems to be solved by the present invention, it is necessary that the thickness of the internal electrode at the portion where the internal electrode comes closest is thicker than 1.2 μm and thinner than 3.0 μm. Become. By setting the thickness in this range, it is possible to obtain a multilayer capacitor having a shape close to a rectangular parallelepiped without suppressing structural defects such as short-circuits and cracks, and having a low ESR without lowering the capacitance.

[0100]

As is apparent from the above description, the multilayer capacitor of the present invention is a multilayer capacitor formed by alternately laminating dielectrics and internal electrodes. The structure is such that the internal electrode thickness of the part that is not in contact is larger than the internal electrode thickness of the closest part, and the internal electrode thickness of the closest part and the internal electrode thickness of the part that is not the closest are set in the optimum range. Without lowering the capacitance of
It is possible to prevent a decrease in reliability due to a structural defect such as a short circuit or a crack, and at the same time, to provide an effect of adjusting the external dimensions to a rectangular parallelepiped and to suppress an equivalent series resistance (ESR) to a low level.

[Brief description of the drawings]

FIG. 1 is a structural sectional view of a multilayer capacitor according to Embodiment 1 of the present invention.

FIG. 2 is a structural sectional view of a conventional multilayer capacitor.

FIG. 3 is a process diagram of a method for manufacturing a multilayer capacitor (corresponding to claim 2) according to a second embodiment of the present invention;

FIG. 4 is a process chart of a method for manufacturing a multilayer capacitor (corresponding to claim 3) according to a third embodiment of the present invention;

FIG. 5 is a process chart of a method for manufacturing a multilayer capacitor (corresponding to claim 4) according to a fourth embodiment of the present invention;

FIG. 6 is a process chart of a method for manufacturing a multilayer capacitor (corresponding to claim 5) according to a fifth embodiment of the present invention;

FIG. 7 is a process chart of a method for manufacturing a multilayer capacitor (corresponding to claim 6) according to a sixth embodiment of the present invention;

FIG. 8 is a process chart of a method for manufacturing a multilayer capacitor (corresponding to claim 7) according to a seventh embodiment of the present invention;

FIG. 9 is a process chart of a method for manufacturing a multilayer capacitor (corresponding to claim 8) according to an eighth embodiment of the present invention;

FIG. 10 is a process chart of a method for manufacturing a multilayer capacitor (corresponding to claim 9) according to a ninth embodiment of the present invention;

FIG. 11 is an explanatory diagram of manufacturing an internal electrode using a screen printing plate according to Embodiment 10 of the present invention.

FIG. 12 is a frequency characteristic diagram of an equivalent series resistance in the multilayer capacitor according to the present invention and the conventional structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Multilayer capacitor 11 Dielectric layer 12 First internal electrode layer 13 Second internal electrode layer 14 External electrode 15 Part where internal electrode is not closest 16 Part where internal electrode is closest 17 Length 18a Part where internal electrode is closest 18b Thickness at the part where the internal electrode does not come in closest contact 19 Width

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuyuki Okano 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term (reference) in Matsushita Electric Industrial Co., Ltd. 5E001 AB03 AC04 AH00 AJ01 5E082 AA01 AB03 EE04 EE23 FF05 FG04

Claims (12)

[Claims] In a multilayer capacitor formed by alternately stacking dielectrics and internal electrodes, the internal electrode thickness of a portion where the internal electrodes are not closest to each other in the stacking direction is the internal electrode thickness of a portion where the internal electrodes are closest. A multilayer capacitor characterized by being larger. 2. The multilayer capacitor according to claim 1, wherein the thickness of the internal electrode at a portion where the internal electrode is closest is larger than 1.2 μm and less than 3.0 μm. 3. The thickness of the internal electrode at a portion where the internal electrode is closest is larger than 1.2 μm and less than 3.0 μm, and the thickness of the internal electrode at a portion where the internal electrode is not closest is the inside of the portion where the internal electrode is closest. 2. The multilayer capacitor according to claim 1, wherein the thickness of the multilayer capacitor is approximately twice the thickness of the electrode. 4. The method for producing a multilayer capacitor according to claim 1, wherein a step of thermocompression bonding a sheet having a dielectric layer applied and formed on a support film to a support plate; Step 2 of thermocompression bonding the sheet on which the internal electrode layer is patterned on the thermocompression-bonded dielectric layer, and positioning the sheet on which the second internal electrode layer is patterned on the support film, and Step 3 of thermocompression bonding on the press-bonded first internal electrode layer. Steps 1 to 3 are sequentially repeated, and finally, step 1 is performed to obtain a laminate. Manufacturing method of multilayer capacitor. 5. The method of manufacturing a multilayer capacitor according to claim 1, wherein a step of thermocompression bonding a sheet having a dielectric layer formed on the support film onto a support plate, and a step of: Forming a pattern of the internal electrode layer and then aligning the first internal electrode layer to obtain a patterned internal electrode sheet; and positioning the internal electrode sheet obtained in the step 2 and performing the thermocompression bonding. And a step 3 of thermocompression bonding on the formed dielectric layer. The steps 1 to 3 are sequentially repeated, and finally the step 1 is performed to obtain a multilayer body. Method. 6. The method for manufacturing a multilayer capacitor according to claim 1, wherein a step of thermocompression bonding a sheet having a dielectric layer applied and formed on a support film to a support plate; Step 2 of obtaining an internal electrode sheet by simultaneously patterning the internal electrode layer and the second internal electrode layer, and Step 3 of thermocompression bonding the internal electrode sheet obtained in Step 2 on the thermocompression-bonded dielectric layer Wherein the steps 1 to 3 are sequentially repeated, and finally the step 1 is performed to obtain a multilayer body. 7. The method for manufacturing a multilayer capacitor according to claim 1, wherein a step of thermocompression bonding a sheet on which a dielectric layer is formed on a support film is performed on a support plate; Step 2 of patterning a first internal electrode layer on the dielectric layer, and aligning and patterning a second internal electrode layer on the first internal electrode layer to provide an internal electrode layer. Step 3 of obtaining a dielectric sheet;
Step 4 of thermocompression bonding the dielectric sheet having the internal electrode layer obtained in 3 on the thermocompression-bonded dielectric layer,
A method for manufacturing a multilayer capacitor, comprising, after performing the step 1, repeating the steps 2 to 4 to obtain a multilayer body. 8. The method for manufacturing a multilayer capacitor according to claim 1, wherein a step of thermocompression bonding a sheet having a dielectric layer formed on a support film to a support plate, and a step of coating and forming the sheet on the support film. Forming a first internal electrode layer and a second internal electrode layer on the dielectric layer at the same time to obtain a dielectric sheet having the internal electrode layer; Step 3 of thermocompression-bonding the dielectric sheet provided with the internal electrode layer obtained in Step 2 above. After performing Step 1, Step 2 and Step 3 are repeated to obtain a laminate. A method for manufacturing a multilayer capacitor, comprising: 9. The method for manufacturing a multilayer capacitor according to claim 1, wherein a first internal electrode layer is patterned on the support film, and a second internal electrode layer is formed on the first internal electrode layer. Step 2 of patterning by aligning electrode layers
A step 3 of coating and forming a dielectric layer on the first and second internal electrode layers to obtain a dielectric sheet having the internal electrode layer; and a step 3 on a support plate. Step 4 of thermocompression-bonding the obtained dielectric sheet, and Step 5 of thermocompression-bonding a sheet obtained by applying and forming a dielectric layer on a support film,
A method for manufacturing a multilayer capacitor, comprising repeating Steps 1 to 4 and then performing Step 5 to obtain a multilayer body. 10. The method for manufacturing a multilayer capacitor according to claim 1, wherein a first internal electrode layer and a second internal electrode layer are aligned on a support film, and a pattern is formed at the same time. A step of coating a dielectric layer on the first internal electrode layer and the second internal electrode layer to obtain a dielectric sheet having the internal electrode layer, and a step of forming a dielectric sheet having the internal electrode layer on the support plate. Step 3 of thermocompression bonding of the body sheet and Step 4 of thermocompression bonding of a sheet having a dielectric layer coated and formed on a support film. Steps 1 to 3 are sequentially repeated, and finally Step 4 is performed. A method for manufacturing a multilayer capacitor, comprising: obtaining a multilayer body. 11. A laminate produced by the production method according to claim 3, wherein the internal electrode layer on the cut surface is
It is characterized in that cutting is performed in units of one unit so that the internal electrode layers of each other become the internal electrode layer of the closest part, and an external electrode is applied and fired so as to be electrically connected to the internal electrode. Manufacturing method of multilayer capacitor. 12. A method for forming an internal electrode layer is a screen printing method, in which an electrode paste discharge amount at a desired screen discharge position is controlled by changing an aperture ratio or a gauze thickness per unit area of a screen, The method for manufacturing a multilayer capacitor according to any one of claims 6, 8, and 10, wherein an internal electrode layer having a different thickness depending on a discharge position is formed by one screen printing.