JP2779896B2 - Manufacturing method of laminated electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer electronic component comprising a plurality of ceramic layers and a plurality of conductor films alternately stacked, and more particularly to a method for manufacturing a multilayer ceramic capacitor.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view of an example of a conventional multilayer ceramic capacitor. As shown in FIG. 1, the multilayer ceramic capacitor includes a plurality of dielectric layers 10 and a plurality of internal electrodes 11 alternately stacked. Outermost internal electrode 1 among multiple layers of internal electrodes 11
A pair of protective layers 12 and 12 are respectively formed on the outer side of 1. The ends of the internal electrodes 11 in a plurality of layers are electrically connected alternately by a pair of external electrodes 13.

Here, the dielectric layer 10 is made of a ceramic mainly composed of a dielectric material such as barium titanate. The internal electrode 11 is made of silver, silver-palladium,
It is made of a metal film formed by firing a conductive paste mainly containing a metal powder such as palladium, platinum or nickel. The protective layer 12 is made of ceramic having the same composition as the dielectric layer 10. Further, the external electrode 13 is
1 is made of a conductive material having the same composition.

Next, an example of a method for manufacturing the conventional multilayer ceramic capacitor will be described.

First, an organic binder, an organic solvent, and the like are added to ceramic powder such as barium titanate and kneaded to prepare a slurry containing barium titanate powder as a main component.
The slurry is applied to a running polyethylene terephthalate (PET) film in a film form by a doctor blade method, and the film-form slurry is dried on a PET film as it is to obtain a barium titanate powder. A ceramic green sheet as a component is obtained.

Next, a conductive paste film is printed and formed in a predetermined pattern on the ceramic green sheet by a screen printing method. Then, a plurality of ceramic green sheets on which the conductive paste films are formed are stacked so that the conductive paste films face each other with the ceramic green sheets interposed therebetween. Further, several ceramic green sheets on which the conductive paste is not printed are stacked on the upper and lower surfaces of the plurality of stacked ceramic green sheets.
Then, a large pressure is applied from above and below to press the entirety of these ceramic green sheets.

Next, these ceramic green sheets in a laminated state are cut into small dice to form a laminated chip, and the laminated chip is fired at 1200 to 1400 ° C. By this firing, the conductive paste film is sintered to become an internal electrode made of a metal film, and the ceramic green sheet sandwiched between the internal electrodes is sintered to become a dielectric layer made of a ceramic sheet, The ceramic green sheet located outside the internal electrode is sintered to form a protective layer made of the ceramic sheet.

Next, a conductive paste is baked on both end surfaces of the fired multilayer chip to form external electrodes, and the internal electrodes are alternately electrically connected by the external electrodes to complete a multilayer ceramic capacitor.

[0009]

In the above-mentioned conventional method for manufacturing a multilayer ceramic capacitor, when the multilayer chip is fired, the firing shrinkage of the conductive paste film for the internal electrode and the ceramic shrinkage for the protective layer are reduced. Since the firing shrinkage of the green sheet is considerably different, uneven internal stress is generated, and the protective layer and the internal electrode of the formed laminated chip are locally peeled off as shown by the portion A in FIG. Hereinafter, this will be referred to as “delamination”), which may cause variations in electrical characteristics.

The present invention has been made in order to solve the above-mentioned problems, and has a multilayer ceramic capacitor in which internal stress is made uniform and delamination is not caused between an internal electrode and a protective layer. It is an object of the present invention to obtain a method of manufacturing a multilayer electronic component having less variation in electrical characteristics.

[0011]

In order to achieve the above object, a method for manufacturing a laminated electronic component according to the present invention comprises the steps of: alternately laminating a ceramic green sheet and a conductive paste film; A laminated chip composed of a pair of ceramic green sheets for a protective layer laminated outside a pair of conductive paste films located at the outermost position is formed, and the laminated chip is fired and sintered. Manufacture of a laminated electronic component in which an external electrode is formed by baking a conductive paste on an end portion of a multilayer chip and internal electrodes made of the sintered conductive paste film are alternately electrically connected by the external electrode. In the method, as the ceramic green sheet for the protective layer, a firing rate closer to a firing shrinkage rate of the conductive paste film than a firing shrinkage rate of the ceramic green sheet is used. Using a ceramic green sheet having a shrinkage.

Here, as a material of the dielectric layer, for example, a ceramic mainly composed of a dielectric such as barium titanate, strontium titanate, and lead titanate can be used. Further, as a material of the internal electrode, a film-like material obtained by firing a conductive paste containing silver, silver-palladium, platinum, nickel, or the like as a main component can be used.

As a method of making the firing shrinkage of the ceramic green sheet for the protective layer closer to the firing shrinkage of the conductive paste film, for example, the ceramic green sheet for the protective layer is made of a metal and / or a metal which is less than the ceramic green sheet for the dielectric.
Alternatively, a method of adding a large amount of a metal oxide to make the sheet composition different from that of the ceramic green sheet for a dielectric can be used. Here, the protective layer ceramic
The firing shrinkage of the black green sheet
Delamination, cracking, etc.
Therefore, the firing shrinkage ratio is
Means the rate of shrinkage over time.

As the metal and / or metal oxide contained in the ceramic green sheet for the protective layer, the same metal as the main component metal of the conductive paste film and / or an oxide of the metal may have desired characteristics. It is preferable in manufacturing a laminated electronic component.

[0015]

According to the first to third aspects of the present invention, when the laminated chip is fired, the ceramic green sheet for the protective layer shrinks in a state close to the shrinkage rate of the conductive paste film for the internal electrode. A large stress is not unevenly applied to the inside of the multilayer electronic component due to the shrinkage of the layer ceramic green sheet, and the inside of the multilayer electronic component sinters relatively uniformly.

According to the second aspect of the present invention, it is only necessary to prepare a sheet having a different composition. Therefore, it is necessary to provide a separate step for changing the firing shrinkage of the ceramic green sheet for the protective layer. Absent.

According to the third aspect of the present invention, the difference in the amount of shrinkage between the conductive paste film and the ceramic green sheet for the protective layer during firing of the multilayer ceramic capacitor is further reduced. No uniform internal stress occurs and no delamination occurs.

[0018]

【Example】

Examples 1 to 4 and Comparative Examples 1 to 4 Barium titanate powder, polyvinyl butyral, ethanol, water and a phosphate dispersant were weighed at the ratio shown in Table 1, and these were put in a ball mill and mixed for about 24 hours. Then, a slurry containing barium titanate powder as a main component was prepared.

[0019]

[Table 1]

Next, the slurry is applied to a running PET film by a doctor blade method to a predetermined thickness in the form of a film.
Dry while running the film, cut to a predetermined size,
A ceramic green sheet for a dielectric layer containing barium titanate as a main component was formed.

Next, a conductive paste containing nickel, ethylcellulose and butyl carbitol at a ratio shown in Table 2 is printed in a predetermined pattern on the ceramic green sheet for a dielectric layer by a screen printing method. A conductive paste film for an internal electrode was formed.

[0022]

[Table 2]

Further, barium titanate powder, nickel powder, polyvinyl butyral, ethanol and a phosphate dispersant were weighed in the proportions shown in Table 3, and they were placed in a ball mill and mixed for about 24 hours to obtain a slurry. Was prepared in the same manner as in the preparation of the ceramic green sheet for the dielectric.
This protective layer ceramic green sheet contains nickel powder in an amount of 1 to 40 with respect to 100 parts by weight of barium titanate.
In the range of parts by weight, it is contained more than the ceramic green sheet for the dielectric layer.

[0024]

[Table 3]

Next, several to several tens of ceramic green sheets for dielectric layers on which conductive paste films for internal electrodes are printed are laminated, and several ceramic green sheets for protective layers are laminated on the upper and lower surfaces. A large pressure was applied from above and below to press the entirety of these ceramic green sheets. These laminated and pressed ceramic green sheets were cut to form small dice-like laminated chips.

Next, the laminated chips are put into
Fired at 00 ° C. By this firing, the conductive paste film is sintered to become an internal electrode made of a metallic film, and the ceramic green sheet sandwiched between the internal electrodes is sintered to become a dielectric layer made of a ceramic sheet, The ceramic green sheet located outside the internal electrode was sintered to form a protective layer made of the ceramic sheet.

Here, the nickel powder contained in the ceramic green sheet for the protective layer becomes nickel oxide when firing is performed in an oxidizing atmosphere, and becomes metallic when firing is performed in a reducing atmosphere. It will be present as nickel.

Next, a conductive paste containing nickel powder as a main component is baked on both end surfaces of the fired laminated chip to form a pair of external electrodes, and the internal electrodes are electrically connected alternately by the external electrodes. Thus, a multilayer ceramic capacitor as shown in FIG. 1 was completed.

In this multilayer ceramic capacitor, as shown in the figure, a plurality of dielectric layers 20 and a plurality of internal electrodes 21 are alternately laminated, and the outermost one of the plurality of internal electrodes 21 is formed. Outside the internal electrode 21, a pair of protective layers 2
2 and 22 are laminated, and the ends of the internal electrodes 21 of a plurality of layers are electrically connected alternately by a pair of external electrodes 23 and 23.

With respect to the obtained multilayer ceramic capacitor, the weight of nickel (Ni) powder (parts by weight based on 100 parts by weight of barium titanate) contained in the ceramic green sheet for the protective layer, and the rate of delamination ( %) And the insulation resistance (MΩ) between the external electrodes 23, 23, the results were as shown in Table 4.

[0031]

[Table 4]

From the above results, it was found that the nickel powder contained barium titanate powder 1 in the ceramic green sheet for the protective layer.
It has been found that when the content is more than 5 parts by weight and more than the dielectric layer 20 with respect to 00 parts by weight, the occurrence rate of delamination becomes 0%. However, if the amount of the nickel powder contained in the protective layer ceramic green sheet is at least 40 parts by weight based on 100 parts by weight of the barium titanate powder and is larger than that of the dielectric layer ceramic green sheet, the distance between the external electrodes 23 is reduced. Greatly reduced the insulation resistance, making it unusable as a capacitor.

Accordingly, the weight of the nickel powder contained in the ceramic green sheet for the protective layer more than that of the ceramic green sheet for the dielectric layer is as follows.
The range of 5 to 35 parts by weight, that is, the range of Examples 1 to 4 is preferable with respect to 00 parts by weight.

Examples 5 to 9 In the ceramic green sheet for the protective layer, 10 parts by weight of metal powder of the type shown in Table 5 was added to 100 parts by weight of barium titanate, more than the ceramic green sheet for the dielectric layer. A multilayer ceramic capacitor was manufactured in the same manner as in Examples 1 to 4 except that the multilayer ceramic capacitor was contained.
(%) And the insulation resistance (MΩ) between the external electrodes were as shown in Table 5.

[0035]

[Table 5]

From the above results, it was found that the same effect can be obtained even when a metal powder other than nickel is contained in the ceramic green sheet for the protective layer.

Examples 10 to 12 In the ceramic green sheet for the protective layer, 2 shown in Table 6
A multilayer ceramic capacitor was prepared in the same manner as in Examples 1 to 4, except that at least 10 kinds of metal powders were contained in 100 parts by weight of barium titanate, more than the ceramic green sheet for a dielectric layer. Manufacture and delamination rate of this multilayer ceramic capacitor
(%) And the insulation resistance (MΩ) between the external electrodes were inspected.

[0038]

[Table 6]

From the above results, it was found that the same effect can be obtained even when two or more kinds of metal powders are contained in the ceramic green sheet for the protective layer.

[0040]

According to the first to third aspects of the present invention, when the laminated chip is fired, the ceramic green sheet for the protective layer contracts in a state close to the contraction rate of the conductive paste film for the internal electrode. In addition, a large stress is not unevenly applied to the inside of the multilayer electronic component due to the shrinkage of the ceramic green sheet for the protective layer, and the inside of the multilayer electronic component sinters relatively uniformly. Therefore, it is possible to obtain a multilayer electronic component having relatively uniform internal stress and little variation in electrical characteristics.
Further, a laminated electronic component having a large number of laminated layers can be obtained.

According to the second aspect of the present invention, since it is only necessary to prepare a sheet having a different composition, it is necessary to provide a separate step for changing the firing shrinkage of the ceramic green sheet for the protective layer. Therefore, the laminated electronic component according to claim 1 can be easily realized.

Further, according to the third aspect of the present invention, since delamination of the multilayer ceramic capacitor can be prevented, the yield of the multilayer ceramic capacitor can be improved and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of a multilayer ceramic capacitor manufactured by a method for manufacturing a multilayer ceramic capacitor according to the present invention.

FIG. 2 is a cross-sectional view of an example of a multilayer ceramic capacitor manufactured by a conventional method for manufacturing a multilayer ceramic capacitor.

[Explanation of symbols]

 Reference Signs List 20 dielectric layer 21 internal electrode 22 protective layer 23 external electrode

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01G 4/12 364 H01G 4/12 346

Claims (3)

(57) [Claims] 1. A ceramic green sheet and a conductive paste film alternately laminated, and a pair of protection layers laminated outside a pair of outermost conductive paste films among the conductive paste films. A laminated chip composed of a ceramic green sheet for a layer was formed, the laminated chip was fired and sintered, and a conductive paste was baked on the end of the laminated chip to form an external electrode, which was then sintered. In the method for manufacturing a laminated electronic component in which internal electrodes made of the conductive paste film are electrically connected alternately by the external electrodes, the ceramic green sheet for the protective layer may be more than a firing shrinkage rate of the ceramic green sheet. A laminated electronic device using a ceramic green sheet having a firing shrinkage ratio close to the firing shrinkage ratio of the conductive paste film. Method of manufacturing the goods. 2. The method according to claim 1, wherein the ceramic green sheet for the protective layer has a composition different from that of the ceramic green sheet. 3. The method for manufacturing a multilayer electronic component according to claim 1, wherein the multilayer electronic component is a multilayer ceramic capacitor.