JP3148387B2 - Manufacturing method of multilayer ceramic capacitor - 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 multilayer ceramic capacitor used for various electronic devices.

[0002]

2. Description of the Related Art A conventional multilayer ceramic capacitor is formed by forming a ceramic slurry obtained by mixing a ceramic powder with an organic binder into a ceramic green sheet (hereinafter simply referred to as a sheet) by a doctor blade method or a roll method, and forming the sheet on the sheet. A plurality of sheets on which an internal electrode print layer is formed to form a dielectric layer having an internal electrode layer, and the internal electrode paste is printed above and below the dielectric layer. A method of bonding a dummy layer consisting of only green sheets by laminating a plurality of sheets that do not have a sheet, or a method of repeatedly printing a ceramic powder paste composed of a ceramic powder and an organic binder to form a dummy layer, and then printing an internal electrode paste and a ceramic powder paste Are alternately repeated to form a dielectric layer, and a dummy layer is further formed thereon. To obtain a laminate by a method of repeatedly printing a ceramic powder paste, which binder removal, sintering, it was prepared by adding processing such as forming the terminal electrodes.

In the former method of laminating sheets, the laminating speed is high and the production can be performed with high efficiency.
When the thickness is 0 μm or less, film cracking occurs due to sheet peeling due to static electricity of the sheet and the carrier film, and handling properties are extremely deteriorated, so that lamination becomes difficult. On the other hand, in the latter method by screen printing, since the printing thickness can be easily reduced to 10 μm or less, the dielectric layer in which the internal electrode paste printing and the ceramic powder paste printing are alternately laminated can be thinned, and the effective dielectric layer can be reduced. The capacitance per body stack can be increased. However, since the printing is repeated by a method of alternately laminating the internal electrode paste printing and the ceramic powder paste printing, a step of 20 to 50 μm is generated in a thickness portion of the internal electrode paste printing by the printing layer made of the ceramic powder, and the internal electrode pattern is formed. Ceramic cracks occur along the
The undulation of the internal electrode occurs, and several tens of times of repeated printing are required to eliminate the step, which has a disadvantage that the laminating speed is extremely slow and the production cost is increased.

[0004]

As described above, the present invention solves the problem of the occurrence of steps due to the thickness of the internal electrode paste printing, and provides a method of manufacturing a low-cost multilayer ceramic capacitor with good productivity. To provide.

[0005]

In order to solve this problem, the present invention provides a ceramic powder comprising a ferroelectric ceramic powder and an organic binder by using two or more types of printing screens having different aperture ratios. The paste is repeatedly printed to form a first printed layer. Further, the ceramic powder paste and the internal electrode paste made of a metal component are alternately and repeatedly printed on the upper surface of the printed layer to have internal electrodes. After forming the dielectric layer, on the upper surface of the dielectric layer,
It is another object of the present invention to provide a method for manufacturing a laminated ceramic capacitor, comprising a step of repeatedly printing the ceramic powder paste to form a second printed layer to produce a laminate.

[0006]

According to the manufacturing method of the present invention, as shown in FIG. 2, a stainless mesh 8 having an opening ratio A9 of 43% is used.
A printing pattern is formed by the screen emulsion 12,
A plating layer 11 is applied to the stainless mesh to a thickness of 10 μm, and then unnecessary emulsion is dissolved with a solvent to leave the screen emulsion 12, leaving an aperture ratio A9 and 43% of 43%.
% Of the aperture screen B10. These two types of aperture ratio A9 and aperture ratio B
When the multilayer body of the multilayer ceramic capacitor is formed by using a printing screen having the number 10, the paste supplied from the aperture ratio A9 of 43% is large, and the paste supplied from the aperture ratio B10 of 10% is small. The end portion of the printing surface printed by this printing screen becomes thin because the supply amount of the paste is small, and the portion having the aperture ratio A9 of 43% becomes large because the supply amount of the paste increases. By using a printing screen having these two types of aperture ratios, a step of 20 to 50 μm in the thickness portion of the internal electrode paste printing by the printing layer made of ceramic powder is eliminated. In this case, two or more different aperture ratios in one screen may be used depending on the paste used and printing conditions. As described above, by using a printing screen having two types of aperture ratios for ceramic powder paste printing and internal electrode paste printing, a thick portion can be thinned and flattened. Can be eliminated with a single print, and dozens of prints are not required to eliminate the unevenness, resulting in extremely high productivity.
Production costs are inevitably reduced.

[0007]

EXAMPLES The production method of the present invention will be described in detail below with reference to examples.

A ceramic powder paste was prepared by mixing a lead-based perovskite dielectric powder with a solvent such as ethyl cellosolve, butyl carbitol, or butyl butyl phthalyl glycolate, and a binder of polyvinyl butyral.
A commercially available silver-palladium paste was prepared as the internal electrode paste. As a printing screen of the internal electrode paste and the ceramic powder paste, as shown in FIG. 2, two types of 43% aperture ratios A9 and 10% aperture ratios B10 in which the screen emulsion 12 was left and the plating layer 11 was formed were formed. The applied # 400 stainless mesh was used. On the other hand, a stainless mesh # 400 having the above two types of aperture ratios was also used as a printing screen for the internal electrode paste. In addition, similarly to the printing of the internal electrode, a plated # 400 stainless mesh having two types of aperture ratios is also applied to the dummy layer 5 (see FIG. 1) only of the ceramic powder paste on which the internal electrode paste is not printed. used.

FIG. 1B is a schematic structural view showing a laminating step of the multilayer ceramic capacitor of the present invention and a method of manufacturing the same. However, (A), (B),
(C) shows the order of lamination. As for the part (A) of FIG. 1B, a ceramic powder paste having two types of aperture ratios is provided on a smooth surface of a stainless steel platen 4.
Printing using stainless steel mesh of 400, 100 ° C
And dry for 1 minute. The thickness of one layer of the printing layer made of ceramic powder is about several μm, and at most about 10 μm. Further, the above operation is repeated, and printing is performed for 14 hours.
This shows a step of forming the dummy layer 5 having a thickness of about 100 to 140 μm by performing the above steps. Next, part (B) of FIG. 1B shows a dummy layer 5 of the ceramic powder paste.
An internal electrode paste print having a thickness of about 1 μm and a ceramic powder paste print having a thickness of about several μm and a thickness of at most about 10 μm are alternately laminated on top of each other.
A dielectric layer having a thickness of about 00 to 1200 μm is formed. First, an internal electrode paste is printed, dried at 100 ° C. for 1 minute, and then a ceramic powder paste is printed thereon.
Dry at 1 ° C. for 1 minute in the same manner. Further, the above operation was repeated, and the internal electrode paste printing was performed 76 times and the ceramic powder paste printing was performed 75 times. A process of forming a dielectric layer having an internal electrode layer of the internal electrode printing layer 6 and the printing layer 7 made of ceramic powder in this manner will be described. FIG.
In the above step (B) of (B), a # 400 stainless mesh printing screen having two kinds of aperture ratios plated is used as an internal electrode paste printing screen, and a ceramic powder paste printing screen is used. As
Similarly, two types of 43% aperture ratio A and 10
A printing screen with a% aperture ratio B was used. Since the discharge amount of the ceramic powder paste is partially controlled by the above-described process, the paste supplied from the opening ratio A of 43% is large, and the paste supplied from the opening ratio B of 10% is small. The edge of the printing surface printed by the printing screen having various types of aperture ratios is thin because the supply amount of the paste is small, and the portion having the aperture ratio A of 43% is large because the supply amount is large and the printing surface is thick. Since both ends are thinned by the printing screens having these two types of aperture ratios, they have a flat printing surface. Therefore, the steps corresponding to the printing thickness of the internal electrodes are alleviated, and a flat surface can be formed. In the conventional manufacturing method, the same stainless steel mesh printing screen of # 400 as used when the dummy layer 5 is formed as the ceramic powder paste printing was used. did. Next, as shown in part (C) of FIG. 1 (b), the ceramic powder paste was printed once again with the # 400 stainless mesh having the above two types of aperture ratios,
After drying at 1 ° C. for 1 minute, the above operation was repeated, and printing was performed 14 times to form a dummy layer 5 having a thickness of about 100 to 140 μm, and a laminate having a thickness of about 1.5 mm was formed. . Then, the laminate is cut to a width of 1 to 2 m.
m, a green chip having a length of 2 mm and a thickness of about 1.5 to 1.6 mm, and then removing the binder at 400 ° C.
Sintering was performed at 1000 ° C. to obtain a ceramic sintered body. As shown in FIG. 1A, a silver paste is applied to the exposed end face of the internal electrode layer 2 of the ceramic sintered body 1, and 6
Sintered at 00 ° C to form terminal electrode 3, DC 1 V at 1 KHz
Table 1 shows the results of the measurement of the capacitance.

[0010]

[Table 1]

In the embodiment of the present invention, the printing screen for printing the internal electrode paste of the dielectric layer having the internal electrode layer and the printing screen for printing the ceramic powder paste have two types of plated apertures having different aperture ratios. Although the screen was used, the printing of the internal electrode paste and the printing of the ceramic powder paste and the formation of only the dielectric layer having the internal electrode layer having the internal electrode layer may be performed by using a printing screen having two different aperture ratios plated. Good. In addition, not limited to plating, a material in which the aperture ratio is partially changed by etching, a mold, or the like may be used. Further, the present invention is not limited to the multilayer ceramic capacitor, and may be used for any of multilayer electronic components.

[0012]

As described above, the multilayer ceramic capacitor and the method of manufacturing the same according to the present invention have been described based on the embodiments. As described above, two types of openings are formed in the internal electrode paste printing and the ceramic powder paste printing of the dielectric layer having the internal electrode layer. By using the printing screen having the ratio, conventionally, it is possible to eliminate the occurrence of cracks due to the step of the printing thickness of the internal electrode, the occurrence of undulation of the internal electrode, and to make a flat surface on a single printing, The production cost can be reduced, and a method of manufacturing a high-quality multilayer ceramic capacitor can be provided.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a multilayer ceramic capacitor in which a terminal electrode is applied to a ceramic sintered body and sintered. FIG. 1B is a cross-sectional view illustrating a schematic configuration illustrating a multilayer ceramic capacitor of the present invention and a lamination process thereof.

FIG. 2A is a plan view of a # 400 stainless mesh having two types of aperture ratios, in which a plating layer is formed by plating. FIG. 2B shows AA in FIG.
Sectional view.

[Description of References] (A) Dummy layer printing portion of ceramic powder (B) Dielectric layer printing portion having ceramic powder and internal electrode layer (C) Dummy layer printing portion of ceramic powder 1 Ceramic sintered body (dielectric layer) 2) Internal electrode layer 3 Terminal electrode 4 Stainless steel platen 5 Dummy layer 6 Internal electrode printing layer 7 Printing layer made of ceramic powder 8 Stainless steel mesh 9 Opening ratio A 10 Opening ratio B11 Plating layer 12 Screen emulsion

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01G 4/00-4/40 H01G 13/00-13/06

Claims (1)

(57) [Claims] 1. A first printing layer is formed by repeatedly printing a ceramic powder paste comprising a ferroelectric ceramic powder and an organic binder using two or more kinds of printing screens having different aperture ratios, On the upper surface of the printing layer, the ceramic powder paste and the internal electrode paste made of a metal component are alternately and repeatedly printed to form a dielectric layer having internal electrodes, and then on the upper surface of the dielectric layer,
A method for manufacturing a multilayer ceramic capacitor, comprising a step of repeatedly printing the ceramic powder paste to form a second printed layer to produce a laminate.