JPH06124848A - Manufacture of laminated ceramic capacitor - Google Patents

Abstract

PURPOSE:To provide a high reliability product which allows continuous manufacture by improving the manufacture of the laminated green compact of a multilayer laminated ceramic capacitor. CONSTITUTION:Dielectric slurry is applied plurality of times by 10mum or less in thickness by a gravure roll so as to continuously constitute a dielectric green sheet 4 on a carrier film 1 and an internal electrode film 5 to be printed is formed on the dielectric green sheet 4 by printing plurality of times. At the time of internal electrode film printing, the part of the film is printed on the carrier film outside of the dielectric green sheet as a marker 6 and the marker 6 is used as position guide for forming an internal electrode film to laminate subsequently. Thus, a high reliability laminated ceramic capacitor which suppresses the generation of a pin hole and interlayer peeling is provided and the continuous manufacture of the laminated green compact of the material is allowed.

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 monolithic ceramic capacitor, and more particularly to a method for forming multi-layered green compacts.

[0002]

2. Description of the Related Art Multilayer ceramic capacitors are applied to a wide range of circuits due to their excellent characteristics such as small size and large capacity, long life, and high frequency characteristics, and are especially suitable for surface mounting for downsizing and weight reduction. In order to cope with this, the transition from the lead wire type to the chip type is progressing at a high speed.

Conventionally, in the manufacture of a monolithic ceramic capacitor, a dielectric sheet and an organic binder are mixed and dispersed in a slurry such as a doctor blade to form a green sheet with a certain thickness on a release-treated carrier film. Then, a paste containing Ag, Pd, or the like as a conductor component is printed thereon in a predetermined pattern by screen printing or the like to form an internal electrode film. The green sheets thus obtained were punched and laminated, and then hot pressed to form a capacitor element, which was then subjected to binder removal, firing, and terminal electrode molding to obtain a product.

In the conventional green sheet molding using a doctor blade, it is difficult to stably produce a film thickness of 10 μm or less, and air bubbles existing in the slurry, foreign matters on the carrier film, and entrainment drying conditions at the blade portion. Pinholes are likely to occur due to factors such as the above, and even if conventional multi-layer film formation is performed, the pinholes that are generated cannot be completely removed due to the film thickness relationship, and pinhole defects remain between opposing electrodes after lamination, causing a short circuit, etc. There was a drawback. In addition, when the layers are stacked in order to stack the next layer after the printing and drying of the internal electrodes, a difference in thickness between the green sheets is caused by the thickness of the internal electrodes,
During the hot pressing, the molding is carried out with the air existing in the peripheral portion of the internal electrode pattern, which causes the occurrence of delamination after firing, and there is a problem that the reliability is lowered.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to improve the film forming method and lamination method of laminated green compacts in order to eliminate these drawbacks, and to have excellent reliability without generation of pinholes or delamination. Another object of the present invention is to provide a method for manufacturing a laminated ceramic capacitor.

[0006]

According to the present invention, a slurry of dielectric ceramic powder is used to form a green sheet having a thickness of 10 μm or less on a carrier film by using a gravure roll, and a green sheet is repeatedly formed thereon. A dielectric green sheet is formed by performing the film formation in the same manner at least twice, and the pinhole generated in the first time is filled with the film formation in the second time and thereafter to form a dielectric green sheet having no pinhole. In the same manner as above, when the internal electrodes are printed by film formation on the dielectric green sheet, the film is printed repeatedly twice or more times to fill the pinholes remaining in the internal electrode film and laminated by a completely continuous electrode film. In addition to the internal electrodes that are hidden by the second and subsequent formation of the dielectric green sheet in order to align the lamination of the printed thickness, A part of the electrode film is printed on the carrier film outside the dielectric green sheet to form a film, and a part of the internal electrode film on the carrier film is used as a positioning marker to print the second and subsequent internal electrodes. The manufacturing method is characterized in that it is possible to perform alignment easily, and printing lamination without stacking deviation can be performed, and continuous printing film formation lamination is possible instead of the conventional batch type. Is. That is, according to the present invention, a dielectric ceramic powder green sheet and a conductor paste film as an internal electrode are printed and formed on a release-treated carrier film, and the dielectric green sheet and the conductor paste are further formed thereon. Laminated green compact obtained by repeating film formation is sintered,
In the method for producing a laminated green compact in the method for producing a monolithic ceramic capacitor produced by processing external electrodes, a method of printing a dielectric green sheet by using a gravure roll and repeatedly applying a film having a thickness of 10 μm or less twice or more. A film is formed, and an internal electrode film made of a conductor paste is formed on the dielectric green sheet by repeating printing two or more times, and at the time of printing the internal electrode film, a part of the internal electrode film of the next internal electrode film is formed. A method of manufacturing a monolithic ceramic capacitor, which comprises printing on a carrier film outside a dielectric green sheet so as to serve as a positioning guide during printing.

[0007]

[Function] In the production of a laminated green compact of a monolithic ceramic capacitor, a dielectric green sheet is repeatedly coated with a gravure roll to form a thin film which is sufficiently thin to obtain a small capacity. Moreover, a dielectric green sheet with few pinholes, bubbles, and defects can be obtained, and by similarly forming the internal electrode film by the repeated printing method, pinholes, bubbles, and defects can be obtained. There are few defects such as pressure resistance and delamination of the produced product, and moreover, by printing the inner electrode film as a marker to the outside of the dielectric green sheet, it is possible to continuously manufacture a large number of multilayer laminated green compacts.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1A, a gravure roll is used on the carrier film 1 that has been subjected to a mold release treatment to have a film thickness of about 3 μm.
m first dielectric green sheet 2 was formed. Figure 1
As shown in the external perspective view of FIG. 1A and the side sectional view of FIG. 1B, a large number of through-type pinholes 7 are formed. This one
On the second dielectric green sheet, the second dielectric green sheet is repeatedly formed by repeatedly coating. As shown in FIG. 2, by repeatedly coating and forming the film by the gravure roll, the second slurry invades into the pinhole 7 to fill the pinhole 8 filled with the dielectric slurry. The body green sheet 3 is deposited. In this case, if the thickness of the green sheet formed in advance is 10 μm or more, the second infiltration of the slurry into the pinhole portion may not be completed, and the thickness of the green sheet may be reduced to facilitate the escape of air bubbles. There is a need.

In this embodiment, as shown in FIGS. 8 and 9, by repeatedly coating and forming a green sheet about 3 μm in total, a dielectric green sheet having a thickness of about 9 μm and having no pinhole is formed. I was able to get it. In this case, it can be seen that most of the pinholes are eliminated by the second coating film formation. As shown in FIG. 3, a screen printing method was repeated twice using a conductive paste prepared by mixing Ag and Pd powder on the dielectric green sheet 4 thus obtained, and the internal electrode film 5 was formed by repeating the screen printing method twice. A printed film was formed to a thickness of 3 μm.
As shown in FIG. 4, a second-stage dielectric green sheet 10 is further applied and formed thereon by a gravure roll.
The second-stage dielectric green sheet 10 formed by coating is in a state of being overlaid in the form of a slurry, so that it is also formed on a portion of the first-stage dielectric green sheet 9 where the internal electrode film 5 is absent. Therefore, when the laminated green compact is formed and the press molding is performed, the binder is compressed with the air layer not existing,
The occurrence of delamination failure after sintering could be reduced.
However, as shown in FIG. 5, in this case, the pattern of the printed internal electrodes is hidden by the second-stage dielectric green sheet 10, so that a positional deviation occurs when the second-stage internal electrode patterns are formed by printing. In order to do so, the marker 6 is printed on the carrier film 1 outside the first-stage dielectric green sheet 9 by using the internal electrode film, and the marker is used for alignment when forming the second-stage internal electrode film 5. I used it for the sushi.

In this embodiment, when the internal electrode film 5 of the second and subsequent stages is printed, the marker 6 is confirmed by an image recognition device for alignment, and when the printed film is formed, the sintered chip is cut. Then, the position deviation of the internal electrode was measured and it was 0.1 mm.
The following deviations were possible. With regard to this alignment, the same result could be obtained by a transfer type or a rotary type other than the screen printing. In addition, as shown in FIG. 7B, the internal electrode films are printed such that the positions of the internal electrodes are slightly shifted every other layer, and when the chips are cut into pieces after sintering, the internal electrodes 13 facing each other are exposed at every other layer. It has been formed into a film.

As shown in FIGS. 6 (1a) and 6 (1b), the first-stage dielectric green sheet 9 is repeatedly formed on the carrier sheet 1 by a gravure roll to form a film. As shown in FIG. 6 (2 b), an internal electrode film 5 and a marker 6 are further formed thereon, and then FIG.
a), as shown in FIG. 6 (3b), a second-stage dielectric green sheet is formed thereon, and then, FIG. 6 (4a), FIG.
As shown in b), the marker 6 processed in FIG. 6 (2a) is used as a guide, and the second-stage internal electrode film 5 is formed thereon, and then the markers 6 in FIGS. 6 (5a) and 6 (5b) are formed. As described above, the third-stage dielectric green sheet 15 is formed on the film. The above steps are repeated to obtain a multi-layer laminated green compact. This is pressed and cut into blocks and then sintered, and after sintering, cut into chips, and the side surfaces of the chips 14 are insulated as shown in FIG.
1 is processed to obtain a monolithic ceramic capacitor.

[0012]

As described above, according to the present invention, it is possible to manufacture a small-sized and large-capacity monolithic ceramic capacitor having high reliability in which pinholes and delamination do not occur, and in particular, the manufacture of laminated green compacts. Can be continuously produced, and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a method of an embodiment of the present invention, showing a first dielectric green sheet formed on a carrier film, FIG. 1 (a) is an external perspective view, and FIG. 1 (b) is a diagram. 1
The sectional side view which shows the AA line cross section of (a).

FIG. 2 is a side sectional view showing a state in which a second dielectric green sheet is formed on the first dielectric green sheet prepared in FIG. 1 and at a position corresponding to FIG. 1 (b).

3 shows a state in which an internal electrode film is formed on the dielectric green sheet prepared in FIG. 1, FIG. 3 (a) is a plan view, and FIG. 3 (b) is a line BB in FIG. 3 (a). Side cross-sectional view at FIG.
FIG. 3C is a side sectional view taken along the line CC of FIG.

FIG. 4 is a side sectional view showing a state in which a second-stage dielectric green sheet is formed on the dielectric green sheet having the internal electrode film shown in FIG. 3, and FIG. 4B shows the position corresponding to FIG. 4B, and FIG. 4B shows the position corresponding to FIG.

FIG. 5 is an explanatory diagram illustrating a state where an internal electrode film is used as a marker for alignment.

FIG. 6 is an explanatory view illustrating a procedure for continuously producing a multilayer laminated green compact, and FIG. 6 (1a) is a plan view showing a state in which a first-stage dielectric green sheet is formed on a carrier sheet, 6 (1b) is a side sectional view of FIG. 6 (1a).
6 (2a) is a plan view showing a state in which the internal electrode film and the marker are formed on FIG. 6 (1a), and FIG. 6 (2b) is shown in FIG.
FIG. 3A is a side sectional view in the vicinity of the internal electrode portion of FIG. 6 (3a) is a plan view showing a state in which a second-stage dielectric green sheet is formed on FIG. 6 (2a), FIG. 6 (3b) is a side sectional view of FIG. 6 (3a), and FIG. 6A is a plan view showing a state in which the second-stage internal electrode film and the marker are formed on the second-stage dielectric green sheet of FIG. 6C, and FIG.
FIG. 6 (5a) is a side sectional view of FIG. 6 (a), and FIG. 6 (5a) is a plan view showing a state in which a third-stage dielectric green sheet is formed on the second-stage internal electrode film of FIG. 6 (4a). Figure 6 (5a)
FIG.

FIG. 7 shows a monolithic ceramic capacitor with terminal electrodes attached, FIG. 7 (a) is an external perspective view, and FIG. 7 (b).
Is a side sectional view taken along the line D-D of FIG.

FIG. 8 is a diagram showing the relationship between the number of times of repeated film formation and the thickness of a green sheet when a dielectric green sheet is formed using a gravure roll.

FIG. 9 is a diagram showing the relationship between the number of times of repeated film formation when a dielectric green sheet is formed using a gravure roll and the number of pinholes per 5000 cm ^{2 of the} dielectric green sheet.

[Explanation of symbols]

 1 Carrier Film 2 1st Dielectric Green Sheet 3 2nd Dielectric Green Sheet 4 Dielectric Green Sheet 5 Internal Electrode Film 6 Marker 7 Pinhole 8 Pinhole Embedded with Dielectric Slurry 9 1st Stage Dielectric Green Sheet 10 Second-stage dielectric green sheet 11 Terminal electrode 12 Dielectric layer 13 Internal electrode 14 Chip 15 Third-stage dielectric green sheet

Claims (1)

[Claims] 1. A green sheet of dielectric ceramic powder (hereinafter referred to as a dielectric green sheet) is formed on a release-treated carrier film, and a conductor paste film is printed and formed thereon as an internal electrode, and further formed thereon. In the method for producing a laminated green compact in the method for producing a laminated ceramic capacitor, which is produced by sintering a laminated green compact obtained by repeating the formation of a dielectric green sheet and a conductor paste film, and making an external electrode, A dielectric green sheet is formed by a method in which a film having a thickness of 10 μm or less is repeatedly applied by printing twice or more using a gravure roll, and an internal electrode film made of a conductor paste is formed twice on the dielectric green sheet. The dielectric green sheet is formed by the above repeated printing, and a part of it is used as a positioning guide when printing the next internal electrode film when printing the internal electrode film. Method of manufacturing a multilayer ceramic capacitor, characterized in that the printing on a carrier film side.