JP2001110664A - Laminated ceramic electronic parts and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide laminated ceramic electronic parts with thin ceramic green sheet, capable of completely fixing stripes and pinholes and securely eliminating short circuit trouble and insufficient breakdown voltage even forming an internal electrode by a conductive paste including conductive power with small average diameter, without internal structural drawback and with high capacity due to dielectric layer and high yield. SOLUTION: Laminated ceramic electronic parts are provided with a laminated chip base alternately laminated with a plurality of dielectric layers and internal electrodes as a main structure, and an external electrode on both ends of the laminated chip base. Further, laminated chip base alternately laminated with a dielectric layer 1 of two-layered structure comprising a first layer 1a of a conductive powder with a large average diameter and a second layer 1b of the conductive powder with a small average diameter than that of the first layer 1a, and an internal electrode 2 comprising a conductive powder with average diameter not shorter than that of the second layer 1b and disposed on the internal electrode 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer ceramic electronic component which mainly focuses on the structure of a dielectric layer in relation to an internal electrode, and to an improvement in a method of manufacturing the same.

[0002]

2. Description of the Related Art In order to meet the demand for miniaturization and large-capacity production of multilayer ceramic capacitors, the thickness per dielectric layer has been reduced to increase the number of stacked layers. However, if a thin ceramic green sheet having a thickness of 10 μm or less after drying is formed to form the dielectric layer, pinholes are likely to occur, and these pinholes cause short-circuit failure and withstand voltage failure. Therefore, as the thickness of the dielectric layer becomes thinner, measures to prevent it have become an important issue.

In order to prevent the occurrence of pinholes, at least two dielectric layers are formed by a doctor blade method (Japanese Patent Laid-Open No. 8-37128), and the dielectric powders have different average particle diameters. A method of forming a two-layer dielectric layer (Japanese Patent Laid-Open No. 5-101970) is disclosed.

In these methods, since the doctor blade method is applied as a means for forming a dielectric layer, the thickness of the dielectric layer having a two-layer structure is as large as 6.5 to 7.5 μm, and the thickness is 6 μm.
It is difficult to form a thin ceramic green sheet of μm. Further, even if a thin ceramic grease sheet having a thickness of about 6 μm can be formed, streaks and pinholes are generated in the ceramic green sheet, resulting in many short-circuit failures and withstand voltage failures, resulting in a decrease in the yield of good products. .

Considering the internal electrodes from the relationship with the thickness of the dielectric layer, when the internal electrodes are formed on a thin ceramic green sheet of about 6 μm, the thickness is preferably at most 2 μm. The conductive powder forming the internal electrode has a mean particle size of 1 μm even if it is large.
It needs to be of the order.

However, when a conductive paste containing fine conductive powder having a particle size of 1 μm is applied onto a thin ceramic green sheet having a thickness of about 6 μm, the conductive powder E is formed as shown in FIG. It is inevitable that short-circuit defects and the like due to the fine streaks and the pinholes H of the ceramic green sheet S formed on the film surface of the carrier film F occur frequently.

If the thickness of the ceramic green sheet is only to be reduced, a discharge coater may be used (for example, Japanese Patent Application Laid-Open No. 2-192022, Japanese Patent Publication No. 1-34).
No. 663). However, even when this discharge coater is applied, it is difficult to suppress the above-described streaks and pinholes from being generated in the ceramic green sheet.

[0008] Even if no streaks or pinholes are generated in the ceramic green sheet, when a conductive paste containing fine conductive powder is applied to the ceramic green sheet, the conductive paste as shown in FIG. It is inevitable that the powder E enters between the particles of the dielectric powder forming the ceramic green sheet S to cause a short-circuit failure or the like.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a ceramic green sheet is formed to be thin, and even if a streak or a pinhole is generated, the ceramic green sheet is supplemented with a conductive powder containing a conductive powder having a small average particle diameter. Even if the internal electrode is formed with a conductive paste, the occurrence of short-circuit failure and withstand voltage failure can be reliably prevented,
It is an object of the present invention to provide a multilayer ceramic electronic component which has no internal structural defects, can achieve a high capacity by a dielectric layer, and can improve a product yield, and a method for manufacturing the same.

[0010]

According to a first aspect of the present invention, there is provided a multilayer ceramic electronic component comprising: a multilayer chip body in which a plurality of dielectric layers and internal electrodes are alternately stacked; A first layer of dielectric powder having a large average particle size, provided at both ends of the laminated chip body;
A dielectric layer having a two-layer structure of a second layer of dielectric powder having an average particle size smaller than the first layer and a conductive powder having an average particle size of the second layer or more of the dielectric layer. And a stacked chip body in which a plurality of the internal electrodes positioned on the second layer are alternately stacked.

In the multilayer ceramic electronic component according to a second aspect of the present invention, the dielectric powder has an average particle size of 0.3 to 0.3.
A first layer of 1.3 μm, preferably 0.3-0.8 μm;
The average particle diameter of the dielectric powder is 0.05 to 0.5 μm, preferably a dielectric layer having a two-layer structure of a second layer of 0.05 to 0.2 μm, and the average particle diameter of the conductive powder is 0.2-0.8
It is constituted by providing a laminated chip body in which a plurality of internal electrodes of μm, preferably 0.3 to 0.6 μm are alternately laminated.

In the multilayer ceramic electronic component according to a third aspect of the present invention, a plurality of dielectric layers having a two-layer structure having a maximum layer thickness of 6 μm and internal electrodes having a maximum electrode thickness of 2 μm are alternately laminated. It is comprised by having the laminated chip body which was made.

In the multilayer ceramic electronic component according to a fourth aspect of the present invention, the thickness ratio between the first layer and the second layer is 4: 1.
And a laminated chip body in which a plurality of dielectric layers and internal electrodes having a two-layer structure are alternately laminated in a ratio of 2.

According to a fifth aspect of the present invention, in the method of manufacturing a multilayer ceramic electronic component, a multilayer chip body is obtained by alternately stacking a plurality of dielectric layers and internal electrodes, and external electrodes are connected to the multilayer chip element. In manufacturing the multilayer ceramic electronic component provided at both ends of the body, a first layer of dielectric powder having a large average particle size and a second layer of dielectric powder having an average particle size smaller than the average particle size of the first layer are used. A plurality of dielectric layers having a two-layer structure of a second layer and internal electrodes formed on the second layer from conductive powder having an average particle diameter of at least the second layer of the dielectric layer are alternately laminated. Thus, a laminated chip body is manufactured.

In the method for manufacturing a multilayer ceramic electronic component according to claim 6 of the present invention, the first layer having an average particle diameter of the dielectric powder of 0.3 to 1.3 μm, preferably 0.3 to 0.8 μm. Eyes, average particle size of dielectric powder is 0.05-0.5μ
m, preferably a second layer of 0.05 to 0.2 μm is laminated to form a dielectric layer having a two-layer structure, and the average particle size of the conductive powder is 0.2 to 0.8 μm, preferably Is 0.3 ~
An internal electrode of 0.6 μm is formed on the second layer of the dielectric layer.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a multilayer ceramic electronic component, wherein a discharge coater having an integral structure and two nozzles is used to form a first layer from a dielectric paste containing a dielectric powder. A dielectric layer having a two-layer structure is formed to a thickness of at most 6 μm by laminating a coating film of the first and second layers, and the internal electrode is formed on the second layer of the dielectric layer at an electrode thickness of at most 2 μm. To be formed.

In the method for manufacturing a multilayer ceramic electronic component according to the present invention, a dielectric layer having a two-layer structure is formed such that the thickness ratio between the first layer and the second layer is 4: 1. It has been like that.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 5, the present invention is for manufacturing a multilayer ceramic electronic component. Basically, first, a dielectric material containing BaTiO ₃ as a main component is used. A ceramic green sheet consisting of a dielectric layer having a two-layer structure is formed by applying a dielectric powder paste containing powder, an organic binder, a plasticizer, a solvent, and the like to the film surface of the carrier film using a discharge coater.
An internal electrode is formed by a screen printing method using a conductive paste containing a conductive powder such as d, Ag, and Ni.

Next, a plurality of the ceramic green sheets on which the above-mentioned internal electrodes are formed are alternately laminated with the internal electrodes so as to form a desired sheet laminate, and a protective layer comprising the uppermost and lowermost dielectric layers as necessary. After laminating, a laminated chip body for each component is obtained through a pressing and cutting process. This laminated chip body is subjected to burnout treatment such as an organic binder,
After firing at 1000 ° C to 1400 ° C, Ag, Ag-Pd, N
A manufacturing process is performed by forming external electrodes such as i and Cu on both ends of the laminated chip sintered body.

As shown in FIG. 1, the first layer 1a of the dielectric powder having a large average particle size and the first layer 1a of the first layer 1a having an average particle size as shown in FIG. A ceramic green sheet to be a dielectric layer 1 having a two-layer structure with a second layer 1b of dielectric powder having a smaller average particle size is formed on the film surface of the carrier film F. Further, the internal electrode 2 is formed on the sheet surface of the ceramic green sheet serving as the second layer 1b of the dielectric layer by using a conductive paste containing a conductive powder having an average particle size equal to or larger than the second layer 1b of the dielectric layer 1. Form.

More specifically, the average particle size of the dielectric powder is set to 0.1.
A first layer having a thickness of 3 to 1.3 μm, preferably 0.3 to 0.8 μm, and an average particle diameter of the dielectric powder of 0.05 to 0.5 μm;
Preferably, a second green layer of 0.05 to 0.2 μm is laminated to form a ceramic green sheet to be a dielectric layer having a two-layer structure. The second electrode of the dielectric layer is made of a conductive paste containing a conductive powder having an average particle size of 0.2 to 0.8 μm, preferably 0.3 to 0.6 μm.
It may be formed on the surface of the ceramic green sheet serving as the layer.

The ceramic green sheet can be formed using a discharge coater 3 having an integral structure provided with two nozzles as shown in FIG. The discharge coater 3 is provided with slit-shaped nozzles 30 and 31 with a gap therebetween, and the dielectric powder paste is supplied from the paste reservoirs 32 and 33 through the nozzles 30 and 31 serving as supply ports to the first layer on the film surface of the carrier film F. Then, the ceramic green sheet to be a dielectric layer having a two-layer structure can be formed by applying the layers in the order of the second layer.

At this time, as shown in FIG. 3, the dielectric powder paste for forming the first dielectric layer 1a has a large average particle diameter of the dielectric powder and a high viscosity. Is easy to occur. On the other hand, the dielectric paste forming the second dielectric layer 1b has a small average particle diameter of the dielectric powder and a low viscosity. By filling the defective part,
It can complement the ceramic green sheet of the layer.

By applying the discharge coater, the first and second coating films are laminated from a dielectric paste containing a dielectric powder to form a ceramic green which becomes a dielectric layer having a two-layer structure. The sheet can be formed as thin as 6 μm at the maximum. This ceramic green sheet is
The thickness ratio between the first layer and the second layer is preferably 4: 1 so that the dielectric layer has a two-layer structure. As the discharge coater 3, the nozzles 30 and 31 shown in FIG. 4 are symmetrical and have an integrated structure, and the nozzles 30 and 31 shown in FIG.

Since the first ceramic green sheet has a high viscosity and a small drying shrinkage, it can be formed as a dielectric layer having a predetermined thickness and a predetermined dielectric constant. On the other hand, the ceramic green sheet of the second layer has a low viscosity and a large drying shrinkage, but in order to obtain a desired thickness after drying,
The supply amount can be easily adjusted by changing the gap between the tip of the discharge nozzle and the carrier film, and the generation of streaks and pinholes can be avoided.

The inner electrode is formed on the sheet surface of the ceramic green sheet to be the second layer from a conductive paste containing a conductive powder having an average particle diameter larger than the dielectric powder of the second layer. Since the powder cannot penetrate into the dielectric layer, it is possible to reliably prevent the occurrence of a short-circuit defect or a withstand voltage defect. This internal electrode can be formed to a thin electrode thickness of at most 2 μm by screen printing.

In order to confirm the effectiveness of the present invention, the average particle size of the dielectric powder forming the first ceramic green sheet is set to 0.5, 0.6, 0.8, 1.0, 1.. 2,
Six points of 1.3 μm were selected, and the average particle diameter of the dielectric powder forming the second-layer ceramic green sheet was 0.03.
0.05, 0.1, 0.2, 0.3, 0.5, 0.6μ
m, and a two-layer ceramic green sheet having a first layer of 4 μm and a second layer of 1 μm was prepared with a target of a total thickness of 5 μm. The number of defects was measured. The results are as shown in Table 1 below.

[0028]

[Table 1]

As apparent from Table 1, the average particle diameter of the dielectric powder contained in the dielectric powder paste for the first layer is 0.3 to 1.3 μm, preferably 0.3 to 0.8 μm. It is understood that the average particle diameter of the dielectric powder contained in the dielectric powder paste for the second layer is preferably 0.05 to 0.5 μm, and more preferably 0.05 to 0.2 μm. Further, when the average particle diameter of the dielectric powder contained in the dielectric powder paste for the first layer is 0.4 μm or less and 1.4 μm or more, there are 80% or more defects of 400 samples, and practically, It was confirmed that it was inappropriate.

However, even among the above-mentioned dielectric powders having an appropriate average particle size, since the stripes and pinholes are not completely removed, the average particle size of the conductive powder forming the internal electrode is set to 0%. .1, 0.2, 0.3, 0.
Screen printing was performed using eight points of the conductive paste of 5, 0.6, 0.7, 0.8, and 0.9 μm, and the withstand voltage failure rate was measured using a multilayer ceramic capacitor manufactured using the paste as an internal electrode. The results are as shown in Table 2 below.

[0031]

[Table 2]

As apparent from Table 2, the average particle diameter of the dielectric powder forming the second ceramic green sheet is 0.05 to 0.5 μm, preferably 0.05 to 0.5 μm.
It was found that the average particle diameter of the conductive powder contained in the conductive paste forming the internal electrodes was 0.2 to 0.8 μm, and preferably 0.3 to 0.6 μm.

[0033]

As described above, according to the multilayer ceramic electronic component and the method of manufacturing the same according to the present invention, the ceramic green sheet is formed to be thin, and even if streaks or pinholes are generated, they are complemented. Even if the internal electrode is formed from a conductive paste containing conductive powder with a small average particle size, the occurrence of short-circuit failure and withstand voltage failure can be reliably prevented, there is no internal structural defect, and the dielectric layer increases the capacity. As a result, the product can be configured as a highly reliable product having excellent quality with insulation and withstand voltage, and can also improve product yield.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a sheet structure constituting one layer of a sheet laminate by a method for manufacturing a multilayer ceramic electronic component according to the present invention.

FIG. 2 is an explanatory view showing a nozzle structure of a discharge coater applied by the method for manufacturing a multilayer ceramic electronic component according to the present invention.

FIG. 3 is an explanatory view showing another sheet structure different from FIG. 1 constituting one layer of a sheet laminate by the method for manufacturing a multilayer ceramic electronic component according to the present invention.

FIG. 4 is an explanatory view showing a nozzle structure of a discharge coater different from FIG. 2 applied by the method for manufacturing a multilayer ceramic electronic component according to the present invention.

FIG. 5 is an explanatory view showing a nozzle structure of a discharge coater different from FIGS. 2 and 4 applied by the method for manufacturing a multilayer ceramic electronic component according to the present invention.

FIG. 6 is an explanatory view showing a problem of a sheet structure constituting one layer of a sheet laminate by a method of manufacturing a multilayer ceramic electronic component according to a conventional example.

FIG. 7 is an explanatory view showing a problem of another sheet structure different from FIG. 6 constituting one layer of a sheet laminate by a method of manufacturing a multilayer ceramic electronic component according to a conventional example.

[Description of Signs] 1 Dielectric layer 1a First layer of dielectric layer 1b Second layer of dielectric layer 2 Internal electrode 3 Discharge coater 30, 31 Nozzle

Continuation of the front page (72) Inventor Hisashi Sato 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (72) Inventor Naoyuki 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation F-term (reference) 5E001 AB03 AC09 AC10 AD04 AE02 AE03 AF06 AG00 AH01 AH05 AH06 AH09 AJ01 AJ02 5E082 AA01 AB03 BC35 BC36 BC38 EE04 EE18 EE23 EE35 FG06 FG26 FG27 FG46 FG54 GG10 GG10 GG10

Claims (8)

[Claims] 1. A multilayer ceramic electronic component comprising, as a component body, a multilayer chip body in which a plurality of dielectric layers and internal electrodes are alternately stacked, and external electrodes provided at both ends of the multilayer chip body. A dielectric layer having a two-layer structure of a first layer of dielectric powder having a large particle diameter and a second layer of dielectric powder having an average particle diameter smaller than the first layer; A multi-layer ceramic electronic component comprising a multi-layer chip body formed by alternately laminating a plurality of internal electrodes formed of conductive powder of a second or higher layer and located on the second layer. . 2. The dielectric powder has an average particle size of 0.3 to 1.3.
μm, preferably 0.3 to 0.8 μm of the first layer, and the second layer of dielectric powder having an average particle diameter of 0.05 to 0.5 μm, preferably 0.05 to 0.2 μm. Dielectric layer having a two-layer structure, the average particle size of the conductive powder is 0.2 ~ 0.8μ
2. The multilayer ceramic electronic component according to claim 1, comprising a multilayer chip body in which a plurality of internal electrodes each having a thickness of 0.3 m to 0.6 μm are alternately stacked. 3. A laminated chip body comprising a plurality of dielectric layers having a two-layer structure with a maximum thickness of 6 μm and internal electrodes with a maximum thickness of 2 μm alternately stacked. The multilayer ceramic electronic component according to claim 1. 4. A multilayer chip body comprising a plurality of alternately laminated dielectric layers and internal electrodes having a two-layer structure in a thickness ratio of the first layer to the second layer of 4: 1. The multilayer ceramic electronic component according to any one of claims 1 to 3, wherein 5. A laminated chip body is obtained by alternately laminating a plurality of dielectric layers and internal electrodes, and external electrodes are provided at both ends of the laminated chip body to produce a laminated ceramic electronic component. A dielectric layer having a two-layer structure of a first layer of dielectric powder having a large average particle diameter and a second layer of dielectric powder having an average particle diameter smaller than the average particle diameter of the first layer; A multilayer chip body is manufactured by alternately laminating a plurality of internal electrodes formed on the second layer from conductive powder having a particle diameter of the second layer or more of the dielectric layer. Of manufacturing a multilayer ceramic electronic component. 6. The dielectric powder has an average particle size of 0.3 to 1.3.
μm, preferably 0.3 to 0.8 μm, and a second layer having an average particle size of the dielectric powder of 0.05 to 0.5 μm, preferably 0.05 to 0.2 μm. A dielectric layer having a two-layer structure is formed by laminating, and an internal electrode having an average particle size of the conductive powder of 0.2 to 0.8 μm, preferably 0.3 to 0.6 μm is formed on the second dielectric layer. 6. The method for manufacturing a multilayer ceramic electronic component according to claim 5, wherein the multilayer ceramic electronic component is formed on a layer. 7. A two-layer structure in which a coating film of a first layer and a second layer is laminated from a dielectric paste containing a dielectric powder by using a discharge coater having an integral structure and two nozzles. 6. A dielectric layer having a thickness of at most 6 .mu.m and an internal electrode having a thickness of at most 2 .mu.m on a second layer of the dielectric layer. 3. The method for producing a multilayer ceramic electronic component according to item 1. 8. A dielectric layer having a two-layer structure with a thickness ratio of the first layer to the second layer of 4: 1. 3. The method for producing a multilayer ceramic electronic component according to item 1.