JPH1126279A - Manufacture of laminated ceramic electronic parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form internal electrodes by one time of gravure printing, by forming metallic paste films by gravure printing in such a way that the parts of the films which are not put upon another are made thicker in thickness than the parts which are put upon another with green ceramic sheets. SOLUTION: A metallic paste film 5 which becomes an internal electrode is formed by gravure printing metallic paste composed of nickel powder, an organic binder, and a solvent in a prescribed pattern and drying the paste. The thickness of the film 5 is made thinner at the part which is put upon the corresponding part of another metallic paste film 5 which is faced oppositely to the film 5 with a green ceramic sheet in between than that at the part which is not put upon the another film 5. In addition, the thickness of the part of the film 5 which is put upon the corresponding part of the facing film 5 is adjusted to about 2 μm and that of the part which is not put upon the facing film 5 is adjusted to about 4 μm.

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 multilayer ceramic electronic component such as a multilayer ceramic capacitor.

[0002]

2. Description of the Related Art The demand for miniaturization of electronic components is infinitely increasing in conjunction with the miniaturization and high performance of electronic devices in which they are used. In addition, multilayer ceramic capacitors are required to have a large capacity as well as a small size.

In order to obtain a large-capacity multilayer ceramic capacitor, there is a method of reducing the thickness of a ceramic dielectric layer and increasing the number of layers.

A conventional multilayer ceramic capacitor has been manufactured by the following method. For example, JP-A-63-73
As shown in Japanese Patent Publication No. 514, a large number of independent rectangular patterns of a metal paste film serving as internal electrodes are first formed on a surface of a ceramic raw sheet serving as a ceramic dielectric layer by screen printing. I do. Next, screen printing is again performed on the non-overlapping internal electrodes via the ceramic dielectric layer to form a metal paste film, and the thickness of the non-overlapping internal electrodes is set to the inside of the overlapping portion via the dielectric ceramic layer. Electrode thickness 2
A metal paste film having twice the thickness was formed. Then
The ceramic raw sheet on which the metal paste film is formed is
After the cutting, a plurality of rectangular patterns of the metal paste film are alternately shifted so that the internal electrodes are alternately exposed from both end faces, and a plurality of the layers are laminated and pressure-bonded to obtain a laminated block. Next, the laminate block is cut into raw chips of individual laminated ceramic capacitors. Thereafter, the green chip is fired, and external electrodes are formed on predetermined portions to obtain a multilayer ceramic capacitor.

[0005]

However, according to the above-mentioned method, the thickness of the internal electrode in the portion not overlapping via the dielectric ceramic layer is twice the thickness of the internal electrode in the portion overlapping via the dielectric ceramic layer. In order to form a thick metal paste film, screen printing must be performed in two steps.
In addition to the drawback that the number of processes is increased by one and the number of processes increases, the cost is increased as compared with the related art. In addition, the alignment at the time of the second screen printing is difficult and there is a technical problem in accuracy.

Accordingly, the present invention provides a method of manufacturing a multilayer ceramic electronic component in which internal electrode portions that do not overlap via a dielectric ceramic layer can be formed thicker in one step than internal electrode portions which overlap via a dielectric ceramic layer. It is intended to do so.

[0007]

In order to achieve this object, a method of manufacturing a multilayer ceramic electronic component according to the present invention is directed to a method of manufacturing a multilayer ceramic electronic component. A first step of obtaining and a second step of firing the laminate to form external electrodes at predetermined positions.
And wherein the metal paste film is formed by gravure printing so that a non-overlapping portion is formed thicker than a portion overlapping via the ceramic green sheet, and the above object can be achieved. .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention comprises a first step of alternately laminating a plurality of ceramic raw sheets and a plurality of metal paste films to obtain a laminate, and then the laminating step. Baking the body to form an external electrode at a predetermined position, wherein the metal paste film forms a non-overlapping portion thicker than a portion overlapping via the ceramic green sheet by gravure printing. A method of manufacturing a multilayer ceramic electronic component, wherein internal electrode portions that do not overlap via a dielectric ceramic layer in one step are thicker than internal electrode portions which overlap via a dielectric ceramic layer. Can be formed.

An embodiment of the present invention will be described below with reference to the drawings, taking a multilayer ceramic capacitor as an example.

(Embodiment 1) FIGS. 1 to 7 are perspective views for explaining a method of manufacturing a multilayer ceramic capacitor according to the present embodiment.

First, Ba is used as a dielectric ceramic material.
TiO ₃ as a main component, and BaZr as an auxiliary component
A mixed powder of an oxide to which O ₃ , MnO ₂ and Dy ₂ O ₃ were added was added. This mixed powder was dispersed in an organic solvent together with a polyvinyl butyl alcohol resin-based binder and a plasticizer to obtain a ceramic slurry. Next, this ceramic slurry was applied to one surface of the first support film 1 by a doctor blade method or the like as shown in FIG. 2 and dried to form a ceramic green sheet 4 to be a ceramic dielectric layer. The thickness of the ceramic raw sheet 4 is about 10
μm.

Next, as shown in FIG. 3, a metal paste film 5 made of nickel powder, an organic binder and a solvent is gravure-printed on a second support film 2 in a predetermined pattern and dried to form an internal electrode. Was formed. The printing of the internal electrode paste is intended to obtain a plurality of multilayer ceramic capacitors by cutting after lamination. For this purpose, the formation of the metal paste film 5 serving as the internal electrode requires an independent rectangular pattern. It was formed to be vertically and horizontally aligned.

The shape of the gravure printing plate used in this embodiment is such that the thickness of the metal paste film 5 is smaller than that of the ceramic paste as shown in FIG. The portion overlapping with the metal paste film 5 opposed via the raw sheet 4 is thin.
The portion that does not overlap with the metal paste film 5 is so thick that the portion that does not overlap with the metal paste film 5 has a depth of about 4 μm, so that the portion that does not overlap with the metal paste film 5 has a depth of about 2 μm. . At this time, the thickness of the metal paste film 5 serving as the internal electrode formed on the second support film 2 was as thin as about 2 μm at the overlapping portion and as thick as about 4 μm at the non-overlapping portion, as shown in FIG. .

Next, as shown in FIG. 4, a metal plate 7 is used as a support, and the ceramic raw sheet 4 formed on the first support film 1 shown in FIG. The step of removing the first support film 1
This operation was repeated twice to form the lower raw green ceramic layer 4a.

Subsequently, as shown in FIG. 5, a metal paste film 5 serving as an internal electrode formed on the second support film 2 of FIG. 3 is transferred onto the ceramic raw sheet layer 4a by pressure. The second support film 2 was removed.

Further, the ceramic green sheet 4 formed on the first support film 1 shown in FIG. 2 was transferred onto it by pressure, and the first support film 1 was removed. Thereafter, a metal paste film 5 serving as an internal electrode formed on the second support film 2 shown in FIG.
Is transferred to the metal paste film serving as an internal electrode, which has been previously transferred by pressure, by a predetermined distance as shown in FIG.
The second support film 2 was removed. The pressure transfer of the ceramic raw sheet 4 and the pressure transfer of the metal paste film 5 were repeated to form a laminate in which 201 layers of the metal paste film 5 serving as internal electrodes were formed.

On this laminate, the ceramic green sheet 4 formed on the first support film 1 of FIG. 2 was pressure-transferred, and the first support film 1 was removed. This was repeated 15 times to form a ceramic raw sheet layer serving as an upper ineffective layer, and a completed state of the multilayer block 8 of the multilayer ceramic capacitor in FIG. 6 was obtained. In the above-described steps of the pressure transfer and the lamination, no problem such as transfer failure occurred at any time.

The multilayer block 8 of the multilayer ceramic capacitor is pressed and compressed at a pressure of 500 kgf / cm ² using a press machine, and then cut into a predetermined size to obtain a green chip of the individual multilayer ceramic capacitor. And

This is carried out in the atmosphere from room temperature to a maximum temperature of 350.
The temperature was raised to 30 ° C. in 30 hours, and the temperature was maintained at a maximum temperature of 350 ° C. for 2 hours to remove the binder. Thereafter, in a reducing atmosphere with respect to nickel, specifically, in an atmosphere in which the oxygen concentration is controlled at 600 ° C. or more to an oxygen concentration of 1/100 of the equilibrium oxygen partial pressure of nickel, the maximum temperature is 130 ° C.
This was kept at 0 ° C. for 2 hours and fired to obtain a sintered body, thereby obtaining a multilayer ceramic capacitor element before forming external electrodes.

Next, a copper paste made of copper powder, glass frit, an organic binder and an organic solvent is applied to both end surfaces of the element of the multilayer ceramic capacitor where the internal electrodes are exposed by an immersion method, dried, and then dried under nitrogen. The first layer of the external electrode connected to the internal electrode was formed by processing in a belt-type baking furnace in an atmosphere for 1 hour from introduction to removal and at a maximum temperature of 900 ° C. for 10 minutes. This is electroplated by a barrel plating method to obtain a nickel film of about 3 μm,
Subsequently, about 2 μm of a tin-lead alloy film was formed on the first layer of the above-mentioned external electrode to form a second layer of the external electrode made of a plated metal film, and a completed state of the multilayer ceramic capacitor of the present invention was obtained.

With respect to the obtained one, an appearance inspection, an inspection of electrical characteristics such as capacitance, and an internal structure inspection were performed. As a result, all the inspection results were good and there was no problem.

(Embodiment 2) FIG. 8 is a perspective view for explaining a second embodiment as an example of a method of manufacturing a multilayer ceramic capacitor according to the present invention. This is a sheet in which a metal paste film serving as an internal electrode is formed by gravure printing on a raw sheet.

The method for manufacturing the multilayer ceramic capacitor of the present embodiment will be described in detail below.

The green ceramic sheet 4 formed on one side of the first support film 1 shown in FIG. 2 was used as the first sheet.

On the ceramic raw sheet 4 of the first sheet shown in FIG. 2, gravure printing is performed in a predetermined pattern shape in the same manner as in (Embodiment 1), and dried to form a metal paste film 15 serving as an internal electrode. To form a second sheet shown in FIG. The shape of the plate for the gravure printing was the same as in the first embodiment.

First, a metal plate was used as a support, and the ceramic raw sheet 4 of the first sheet in FIG. 2 was transferred onto the metal plate under pressure to remove the first support film 1. This was repeated 15 times to form a ceramic green sheet layer serving as a lower ineffective layer.

Next, on this ceramic raw sheet layer,
The second sheet having the metal paste film 15 serving as an internal electrode formed on the ceramic raw sheet 4 shown in FIG. 8 was transferred by pressure to remove the first support film 1. Further, a metal paste film 15 serving as an internal electrode is fixed on the metal paste film 15 serving as an internal electrode, as shown in FIG. The first support film 1 was removed by transfer under pressure. This is repeated, and the metal paste film 15 serving as an internal electrode in total
Was formed into a laminate.

On top of this, the ceramic raw sheet 4 of the first sheet of FIG.
Was removed. This was repeated 15 times to form a ceramic raw sheet layer serving as an upper ineffective layer, and a completed product of a multilayer block of a multilayer ceramic capacitor was obtained. In the above-described steps of the pressure transfer and the lamination, no problem such as transfer failure occurred at any time.

The multilayer block of the multilayer ceramic capacitor is subjected to pressure bonding, cutting, binder removal processing and firing in the same manner as in the first embodiment to obtain a sintered body, thereby obtaining an element of the multilayer ceramic capacitor. Then, external electrodes were formed thereon to obtain a completed state of the multilayer ceramic capacitor of the present invention.

With respect to the obtained one, an appearance inspection, an inspection of electrical characteristics such as capacitance, and an internal structure inspection were performed. As a result, all the inspection results were good and there was no problem.

The point of the present invention will be described below. (1) Nickel, which is a base metal, was used as a metal to be used as an internal electrode. However, this is for the purpose of cost reduction, and is not limited thereto. May be used. (2) Specific numerical values are shown for the thickness of the ceramic raw sheet 4, the thickness of the metal paste films 5 and 15 serving as internal electrodes, and the number of layers. When the thickness is small and the number of laminations is large, the effect is particularly large, and it is needless to say that the invention is not limited to these. (3) When forming the metal paste film 5 as shown in FIG. 3, by forming the metal paste film 5 in a size equal to or less than a desired shape, it is possible to prevent a difference in the thickness of the internal electrodes due to the displacement of the internal electrodes. Can be. (4) In the embodiment, the multilayer ceramic capacitor has been described as an example. However, similar effects can be obtained in multilayer ceramic electronic components such as a multilayer varistor and a multilayer thermistor.

[0032]

According to the present invention, unlike the conventional case where screen printing is performed twice, the internal electrodes can be formed by one gravure printing, so that there is no problem of alignment. As a result, high-quality multilayer ceramic electronic components can be manufactured with high productivity and yield, and the industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a shape of an internal electrode of a multilayer ceramic capacitor according to a first embodiment of the present invention, and a positional relationship between the internal electrode and a facing internal electrode.

FIG. 2 is a perspective view for illustrating a method of manufacturing the multilayer ceramic capacitor according to the first embodiment of the present invention.

FIG. 3 is a perspective view for explaining the method for manufacturing the multilayer ceramic capacitor in the first embodiment of the present invention.

FIG. 4 is a perspective view for explaining the method for manufacturing the multilayer ceramic capacitor in the first embodiment of the present invention.

FIG. 5 is a perspective view for illustrating the method for manufacturing the multilayer ceramic capacitor in the first embodiment of the present invention.

FIG. 6 is a perspective view for illustrating the method for manufacturing the multilayer ceramic capacitor in the first embodiment of the present invention.

FIG. 7 is a cross-sectional perspective view showing the shape of a gravure printing plate according to the first embodiment of the present invention.

FIG. 8 is a perspective view for illustrating a method for manufacturing a multilayer ceramic capacitor according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 4 ceramic raw sheet 5 metal paste film 8 laminated block 15 metal paste film

Claims (1)

[Claims] 1. A first step of alternately laminating a plurality of ceramic raw sheets and a plurality of metal paste films to obtain a laminate, and then firing the laminate to form external electrodes at predetermined positions. A method of manufacturing a multilayer ceramic electronic component, wherein a non-overlapping portion of the metal paste film is formed thicker by gravure printing than a overlapping portion through the ceramic green sheet.