JP3460620B2 - Manufacturing method of ceramic laminated 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 ceramic multilayer electronic component such as a multilayer capacitor, and more particularly to a ceramic multilayer electronic component having an improved process for obtaining a ceramic green laminate prior to firing. Manufacturing method.

[0002]

2. Description of the Related Art In manufacturing a ceramic multilayer electronic component such as a multilayer capacitor, first, a ceramic multilayer body in which a plurality of internal electrodes are laminated via a ceramic green sheet is obtained, and the ceramic multilayer body is applied in the thickness direction. Press. Then, the laminate is fired to obtain a ceramic sintered body, and external electrodes are formed on the outer surface of the ceramic sintered body.
A method for manufacturing such a ceramic laminated electronic component is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-335475.

[0003]

When firing the above ceramic laminate, the ceramic green sheet and the internal electrodes shrink. However, the firing shrinkage of the internal electrode is
It is higher than the firing shrinkage of the ceramic green sheet.

In the multilayer capacitor 51, a plurality of internal electrodes 53 are laminated in a ceramic sintered body 52 with ceramic layers interposed therebetween. Since the internal electrode 53 has a large firing shrinkage, the portion 52A where the internal electrode 53 is laminated
The shrinkage ratio of the ceramic layer 52B is larger than that of the ceramic layer 52B on the outer side in the stacking direction with respect to the portion where the internal electrode 53 is stacked. Therefore, as in the multilayer capacitor 51 shown in FIG. 7, in the ceramic sintered body 52, the side surfaces 52a and 52b tend to be concave surfaces that are dented in the center.

In FIG. 7, reference numerals 54 and 55 denote external electrodes. By the way, when mounting the multilayer capacitor 51 on a printed circuit board or the like, the multilayer capacitor 51 is suction-held by the suction head of the mounter. In the multilayer capacitor 51, the upper surface 52 of the ceramic sintered body 52
c and the lower surface 52d are flat. Therefore, the multilayer capacitor 51 is arranged so that the upper surface 52c or the lower surface 52d faces upward.
In the case where is arranged, the multilayer capacitor 51 can be surely sucked and held by the suction head of the mounter.

On the other hand, as shown in FIG.
When the multilayer capacitor 51 is arranged so that 2a faces upward, it is necessary to attract and hold the multilayer capacitor 51 by the suction head on the side surface 52a. However, since the side surface 52a is a concave surface, the suction head cannot reliably suck and hold the multilayer capacitor 51, resulting in a problem that the mounting efficiency is reduced.

In particular, in recent years, ceramic monolithic electronic components such as monolithic capacitors have been downsized, and the vertical dimension, that is, the length between the upper surface 52c and the lower surface 52d of the ceramic sintered body 52, and the lateral direction. Dimension, side 5
The length between 2a and 52b is often close to each other. Therefore, the multilayer capacitor 51 tends to be positioned so that the side surface 52a and the side surface 52b face upward as shown in FIG. Therefore, the above-mentioned suction error tends to further lower the mounting efficiency.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art, to reliably suppress the adsorption failure due to the difference in firing shrinkage between the internal electrode and the ceramic green sheet, and to improve the mounting efficiency. It is to provide a method for manufacturing a ceramic laminated electronic component that can be improved in efficiency.

[0009]

A first invention of the present application is a method of manufacturing a ceramic laminated electronic component in which a plurality of internal electrodes are laminated via ceramic layers, and a ceramic green printed with the internal electrodes. A step of stacking the sheets to obtain a first laminated body, a first pressing step of pressing the first laminated body in the thickness direction, and a first pressing step above and below the first laminated body .
A step of laminating ceramic green sheets made of the same material as that used for the laminated body to obtain a second laminated body, and pressing the second laminated body in the thickness direction with a pressure weaker than that of the first pressing step. A second pressing step, a step of firing the second laminated body to obtain a ceramic sintered body, and a step of forming an external electrode on the outer surface of the ceramic sintered body.

A second invention of the present application is a method of manufacturing a ceramic laminated electronic component in which a plurality of internal electrodes are laminated via ceramic layers, and a mother ceramic green sheet having a plurality of internal electrodes printed thereon is used. Laminating to obtain a laminated body of the first mother, a first pressing step of pressing the laminated body of the first mother in the thickness direction, and a first mother layer above and below the laminated body of the first mother. Used in the laminate
And a step of stacking mother ceramic green sheets made of the same material as described above to obtain a second mother laminated body, and pressing the second mother laminated body in the thickness direction with a pressure weaker than that in the first pressing step. A second pressing step, a step of cutting the second mother laminated body in the thickness direction after the second pressing step in order to obtain a laminated body of individual ceramic laminated electronic component units, and firing the laminated body, The method is characterized by including a step of obtaining a ceramic sintered body and a step of forming an external electrode on an outer surface of the ceramic sintered body.

The method for manufacturing a ceramic laminated electronic component according to the first and second inventions can be used for manufacturing various ceramic laminated electronic components. In a particular aspect of the present invention, a dielectric material is used as a ceramic green sheet. A ceramics-based material is used to manufacture a multilayer capacitor.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

In this embodiment, a ceramic green sheet containing a dielectric ceramic powder such as barium titanate-based ceramic powder as a main component is obtained. The method for forming the ceramic green sheet is not particularly limited, and an appropriate method such as a roll coating method or a doctor blade method can be used.

Next, the ceramic green sheet is punched into a rectangular shape to obtain a rectangular ceramic green sheet. Next, a conductive paste is applied to the upper surface of the rectangular ceramic green sheet to form internal electrodes. In this case, the conductive paste may be Ag-Pd paste or N
It is possible to use an i paste or the like containing an appropriate conductive powder. When forming the internal electrodes, a thin film forming method such as vapor deposition or plating may be used instead of applying the conductive paste.

Next, a rectangular ceramic green sheet on which internal electrodes are printed is laminated. FIG. 2 is a perspective view for explaining this step. Internal electrodes 5 to 8 are formed on the rectangular ceramic green sheets 1 to 4, respectively. As is apparent from FIG. 2, the internal electrodes 5 and 7 formed on the ceramic green sheets 1 and 3 and the internal electrodes 6 and 8 formed on the ceramic green sheets 2 and 4 are drawn out to different end faces after lamination. Is formed. In other words, the plurality of ceramic green sheets on which the internal electrodes are printed are laminated so that the edges of the internal electrodes that are pulled out are alternately opposite sides. In this way, the laminated body 9 shown in FIG. 3 is obtained. In the laminated body 9, the internal electrodes 5, 7 are drawn out to the end face 9a, and the internal electrodes 6, 8 are drawn out to the opposite end face 9b.

In the laminated body 9, the internal electrode 5 has the upper surface 9
It is located on c. That is, in this state, the internal electrode 5 is not embedded in the laminated body 9. The laminated body 9
Is pressed in the thickness direction and a first pressing step is performed.
As a result, the internal electrodes 5 to 8 are firmly adhered to each other via the ceramic green sheets 1 to 4.

Next, as shown in FIG. 4, an appropriate number of plain ceramic green sheets 1 are provided above and below the laminated body 9.
0 and 11 and ceramic green sheets 12 and 13 are laminated respectively. In this way, the second laminated body is obtained,
The second laminate is pressed in the thickness direction and the second pressing step is performed. However, the pressure applied in the second pressing step is lower than the pressure applied in the first pressing step.

Therefore, in the obtained second laminated body, the density of the portion where the ceramic green sheets 10 and 11 are laminated and the portion where the ceramic green sheets 12 and 13 are laminated are the same as those of the first laminated body 9 Lower than the density at. The ceramic green sheet 10,
The portion where 11 is laminated and the portion where the ceramic green sheets 12 and 13 are laminated are hereinafter referred to as an outer layer portion.

That is, by lowering the pressure applied in the second pressing step as compared with the pressure applied in the first pressing step, the density of the outer layer portion becomes higher than that of the first laminate 9. It has been lowered.

Next, the second laminated body is fired to obtain the ceramic sintered body 14 shown in FIG. As described above, upon firing, the firing shrinkage of the internal electrode is higher than the firing shrinkage of the ceramic green sheet. Therefore, the firing shrinkage of the first laminated body portion where the internal electrodes are laminated is relatively large. However, in this embodiment, since the density of the outer layer portion is lower than the density of the laminated body 9,
The ceramic green sheet forming the outer layer portion shrinks more than the ceramic green sheet forming the first laminated body 9.

Therefore, as shown in FIG. 1, in the ceramic sintered body 14, the side surfaces 14e and 14f are concave, but the degree of the concave is smaller than that of the conventional example.

The end surface 14a of the ceramic sintered body 14 is
By forming an external electrode so as to cover 14b,
A multilayer capacitor is obtained. The obtained multilayer capacitor is shown in a sectional view in FIG. In the multilayer capacitor 15, the external electrodes 16 and 17 have the end surfaces 14 a and 1 of the ceramic sintered body 14, respectively.
It is formed so as to cover 4b. External electrodes 16, 17
For the method of forming, apply / bak the conductive paste,
An appropriate method such as a thin film forming method such as vapor deposition, plating or sputtering can be used. The material forming the external electrodes is also not particularly limited, and Ag, A
Any metal material such as g-Pd or Cu can be used.

In the manufacturing method of the present embodiment, as described above, the density of the outer layer portion is lower than the density of the first laminated body 9, so that the obtained ceramic sintered body 14 has a side surface. The degree of depression of 14e and 14f is significantly reduced. Therefore, instead of the upper surface 14c and the lower surface 14d,
Even if the multilayer capacitor 15 is arranged such that the side surfaces 14e and 14f face upward, the suction head of the mounter reliably sucks and holds the multilayer capacitor 15.

In the above embodiment, the method for manufacturing one monolithic capacitor has been described as an example. However, in the present invention, in order to improve the productivity, a mother ceramic green sheet is used and a second mother mother sheet is used. The steps up to the step of obtaining the laminate may be performed in the mother state.

Next, a concrete experimental example will be described. In the following experimental example, the number of laminated internal electrodes was 101, and the thickness of the ceramic layer between the internal electrodes was 5 μm, 1.6 mm × 0.8 m.
An m × 0.8 mm ceramic capacitor was produced.

(Example 1) First, a ceramic slurry containing barium titanate-based ceramic powder was coated on a carrier film by a roll coating method so that the coating thickness was 6 μm, and the coated ceramic slurry was dried. Then, a first mother ceramic green sheet was obtained.

A second mother ceramic green sheet was obtained in the same manner as above, but with a coating thickness of 12 μm. A Ni paste was screen-printed on the first mother ceramic green sheet to form a plurality of internal electrode patterns. Thereafter, a plurality of first mother ceramic green sheets having internal electrode patterns formed thereon were laminated so that the number of laminated internal electrodes was 101 to obtain a first mother laminated body. The laminated body of the first mother was pressed in the thickness direction with a pressure of 800 kgf / cm ² in the thickness direction.

Next, one each of the above-mentioned second mother ceramic green sheets is provided above and below the first mother laminated body.
0 sheets were laminated to obtain a second mother laminated body. The second mother laminate was subjected to a second pressing step by applying a pressure of 500 kgf / cm ^{2 in} the thickness direction.

The laminated body of the second mother obtained as described above was cut into individual laminated capacitor units to obtain laminated bodies of individual laminated capacitor units. The obtained laminated body was fired at 1300 ° C. to obtain a ceramic sintered body.

Finally, in order to enhance the solderability, the conductive paste mainly composed of Cu is applied and baked on both end surfaces of the obtained ceramic sintered body where the internal electrodes are exposed, and the baked electrode film surface is further improved. A multilayer capacitor was obtained by plating Sn with Sn and forming external electrodes.

Comparative Example 1 In Example 1, the pressure applied in the second pressing step was 1000 kgf / c.
A multilayer capacitor was obtained in the same manner as in Example 1 except that m ² was used.

Comparative Example 2 A mother internal electrode pattern was formed in the same manner as in Example 1 on the first mother ceramic green sheet used in Example 1. The first mother ceramic green sheets were laminated in the same manner as in Example 1, and further 10 second ceramic green sheets used in Example 1 were laminated on each of the upper and lower sides to obtain a mother laminated body. This mother laminate is 1400k in the thickness direction.
It was pressed by applying a pressure of gf / cm ² . This mother laminated body was cut into individual laminated capacitor units to obtain individual laminated capacitor unit laminated bodies. This laminated body was fired in the same manner as in Example 1 to obtain a ceramic sintered body, and external electrodes were formed in the same manner as in Example 1 to obtain a laminated capacitor.

(Evaluation of Examples and Comparative Examples) With respect to each of the multilayer capacitors obtained in Example 1 and Comparative Examples 1 and 2, the appearance was observed and the degree of concave shape on the side surface was evaluated. The degree of depression was evaluated by measuring the radius of curvature of the side surface. The results are shown in Table 1 below.

In addition, it was evaluated whether or not a diagonal cut defect occurred when cutting to obtain a laminated body of each laminated capacitor unit from the mother laminated body. Here, the oblique cut refers to a phenomenon in which the side surfaces 21a and 21b of the multilayer body 21 of each multilayer capacitor unit formed by cutting are inclined, as shown in the schematic sectional view of FIG. This is because the density of the mother laminate becomes too high, the cutting blade does not move so as to substantially match the thickness direction of the mother laminate, and the cutting blade bends and is cut in an oblique direction. .

A diagonal cut amount C in FIG. 6, that is, a case where the lateral shift length between the upper surface and the lower surface of the laminated body is 50 μm or more is regarded as an oblique cut defect. The results are also shown in Table 1 below regarding the occurrence ratio of the above-mentioned oblique cut defects.

[0036]

[Table 1]

As is clear from Table 1, in Comparative Examples 1 and 2, the radius of curvature R indicating the degree of concave shape of the side surface is 7 respectively.
While the radius of curvature R is as small as 5 μm in Example 1, it can be understood that the degree of the concave shape of the side surface can be effectively reduced, while it was μm and 6 μm. It is considered that this is because the outer layer portion of the laminate has a relatively low density, so that the outer layer has a higher firing shrinkage rate and the degree of the concave shape is reduced.

Further, in Comparative Example 1, there are 3 oblique cut defects.
It occurs in 5 of 0 multilayer capacitors, and in Comparative Example 2,
In 20 of 30 pieces, the diagonal cut defects did not occur in Example 1. This is a comparative example 2.
Then, in order to reduce the degree of the concave shape, the mother laminate was pressed once by applying a large pressure, so that the density of the mother laminate becomes very high, and oblique cutting defects are likely to occur during cutting. On the other hand, in the embodiment, the first
In neither of the pressing step and the second pressing step, a large pressure is applied as in Comparative Example 2,
This is probably because diagonal cutting is unlikely to occur when cutting the mother laminate.

Therefore, according to the first embodiment, not only the degree of the concave shape of the side surface can be alleviated, but also the occurrence of the oblique cut defect can be effectively suppressed, whereby the productivity of the multilayer capacitor can be improved. I understand. In Comparative Example 1,
Since the pressure of the second time was high, the density of the laminated body was increased too much, and the oblique cut defect occurred.

[0040]

In the method for manufacturing a ceramic laminated electronic component according to the first invention, the ceramic green sheets having the internal electrodes printed thereon are laminated to obtain a first laminated body, and the first laminated body is formed into a first laminated body. After being pressed in the pressing step, used for the first laminated body that constitutes the outer layer portion above and below the first laminated body.
A second laminated body is obtained by laminating ceramic green sheets made of the same material as described above. And the first
The second laminated body is pressed in the thickness direction in the second pressing step with a pressure weaker than that in the pressing step.

Therefore, since the density of the outer layer is relatively low, the firing shrinkage rate of the outer layer is increased during firing, which makes it possible to effectively reduce the degree of concaveness on the side surface of the ceramic sintered body. Become. Therefore, it is possible to provide the ceramic laminated electronic component that can be surely sucked and held by the suction head or the like, and it is possible to enhance the mounting efficiency of the ceramic laminated electronic component.

Further, in the method for manufacturing a ceramic laminated electronic component according to the second invention, the steps from the step of obtaining the first laminated body to the second pressing step in the first invention are performed in a mother state, A laminate of 2 mothers is obtained. Therefore, when the laminated body of the second mother is cut in the thickness direction to obtain a laminated body of each ceramic laminated electronic component unit and fired, the density of the outer layer is relatively lowered as in the first invention. Therefore, it is possible to effectively soften the degree of the concave shape on the side surface of the ceramic sintered body, and suction by a suction head, etc.
It is possible to provide a ceramic laminated electronic component that can be reliably held.

In addition, by relatively lowering the density of the outer layer prior to firing, the degree of concaveness appearing on the side surface due to the difference in firing shrinkage between the internal electrode and the ceramic green sheet is reduced. It is not necessary to apply a large pressure in the first and second pressing steps. Therefore, in the laminated body of the second mother, not only the outer layer but also the density sandwiched between the outer layers does not become so high,
When the second mother laminate is cut, the above-mentioned oblique cut defect is unlikely to occur. Therefore, the yield rate of the ceramic laminated electronic component can be increased, and thereby the productivity of the ceramic laminated electronic component can be increased.

Further, in the present invention, when a ceramic green sheet having a dielectric ceramic as a main component is used and a multilayer capacitor is manufactured as a ceramic multilayer electronic component, the multilayer capacitor has a relatively large number of internal electrode layers. Since there are many, the effect of alleviating the degree of the concave shape on the side surface is more effectively exhibited.

However, the present invention can be used for manufacturing various ceramic laminated electronic components such as a laminated varistor, a laminated inductor, a ceramic laminated piezoelectric resonance component, and a laminated thermistor, other than the laminated capacitor.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining a ceramic sintered body obtained in an example of the present invention.

FIG. 2 is a perspective view illustrating a ceramic green sheet laminated to form a first laminated body and internal electrodes formed on the ceramic green sheet according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a first laminated body prepared in one example of the present invention.

FIG. 4 is a cross-sectional view for explaining a step of obtaining a second laminated body by laminating ceramic green sheets constituting outer layers above and below the first laminated body in one embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a multilayer capacitor obtained in one example of the present invention.

FIG. 6 is a schematic cross-sectional view for explaining an oblique cut defect.

FIG. 7 is a perspective view showing an example of a conventional multilayer capacitor.

[Explanation of symbols]

1-4 ... Ceramic green sheet 5-8 ... internal electrodes 9 ... 1st laminated body 9a, 9b ... end faces 9c ... top surface 9d ... bottom surface 10 to 13 ... Ceramic green sheet forming the outer layer 14 ... Ceramic sintered body 14e, 14f ... Side surface 15 ... Multilayer capacitor 16, 17 ... External electrodes

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-11-97282 (JP, A) JP-A-8-31704 (JP, A) JP-A-8-236393 (JP, A) JP-A-6- 283375 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01G 4/00-4/42

Claims (3)

(57) [Claims] 1. A method for manufacturing a ceramic laminated electronic component, wherein a plurality of internal electrodes are laminated via ceramic layers, wherein a ceramic green sheet on which internal electrodes are printed is laminated to obtain a first laminated body. Steps, a first pressing step of pressing the first laminate in the thickness direction, and the same as that used for the first laminate above and below the first laminate.
A step of stacking ceramic green sheets made of the same material to obtain a second stacked body, and a second pressing step of pressing the second stacked body in the thickness direction with a pressure weaker than that of the first pressing step, A method of manufacturing a ceramic laminated electronic component, comprising: a step of firing the second laminated body to obtain a ceramic sintered body; and a step of forming an external electrode on an outer surface of the ceramic sintered body. 2. A method for manufacturing a ceramic laminated electronic component, wherein a plurality of internal electrodes are laminated via ceramic layers, wherein a mother ceramic green sheet on which a plurality of internal electrodes are printed is laminated, and A step of obtaining a mother laminated body, a first pressing step of pressing the first mother laminated body in a thickness direction, and a first mother laminated body above and below the first mother laminated body.
A step of laminating mother ceramic green sheets made of the same material as used to obtain a second mother laminated body, and a step of forming the second mother laminated body with a pressure weaker than that of the first pressing step. A second pressing step in which the second mother is pressed in the thickness direction, a step of cutting the second mother laminated body in the thickness direction after the second pressing step in order to obtain a laminated body of individual ceramic laminated electronic component units, and the laminated body And a step of forming an external electrode on the outer surface of the ceramic sintered body, the method for manufacturing a ceramic laminated electronic component. 3. The method for producing a ceramic multilayer electronic component according to claim 1, wherein the ceramic green sheet contains a dielectric ceramic as a main component, and a multilayer capacitor is produced as a ceramic multilayer electronic component.