JPH10149942A - Multilayered ceramic capacitor and manufacture of multilayered chip inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the occurrence of voids in an external electrode by forming the electrode by spraying metal powder-containing paste prepared by scattering low-resistance metal powder in an organic vehicle and drying and baking the paste. SOLUTION: Paste prepared by mixing low-resistance metal powder in a organic vehicle and kneading the vehicle after adding glass frit to the vehicle is used for the formation of an external electrode. The external electrode paste is jetted into the output port of an internal electrode layer masked with a masking jig 6 from the spray nozzle 5 of a spraying device. After the paste is sprayed, the past is dried and baked and a multilayered ceramic capacitor element 7 is obtained through a plating process. Therefore, the reliability of the element can be improved by reducing the occurrence of delamination troubles in the element by suppressing the occurrence of pores in the external electrode.

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 and a multilayer chip inductor,
In particular, the present invention relates to a method for forming an external electrode.

[0002]

2. Description of the Related Art A conventional technique will be described below using a ceramic capacitor as an example.

As shown in FIG. 2, a multilayer ceramic capacitor having a structure in which an internal electrode layer 2 made of a metal conductor and a dielectric ceramic layer 1 are alternately laminated inside is conventionally known.
As a manufacturing method, a ceramic powder is formed into a slurry using an organic binder and an organic solvent, and then a sheet having a constant thickness, that is, a green sheet is formed on a film subjected to a release treatment by a doctor blade method or the like.

On the green sheet, palladium (P
d) A paste containing a metal powder in which a low-resistance metal such as silver (Ag) is dispersed in an organic vehicle is screen-printed so as to obtain an outlet 7a for connection to the external electrode 3 in a certain shape, and its green color is obtained. A laminate is obtained by punching out sheets, stacking a plurality of sheets, and performing hot press molding.
There is also a method in which the dielectric ceramic layer is also subjected to screen printing, and a laminate is obtained only by printing.

After that, the binder is removed, baked, and the external electrode 3 connected to the internal electrode layer 2 is applied by dipping, dried and baked. Then, in order to use the external electrode 3 as a solder plating terminal, plating is performed in the order of nickel plating and solder plating.

On the other hand, a multilayer chip inductor connects a conductor pattern printed on a magnetic layer via a through hole provided in the magnetic layer, and laminates the conductor pattern on the magnetic layer to form a spiral coil and a conductor pattern inside the magnetic body. The uppermost layer exposes the tip of the lowermost layer to the opposite side surface of the magnetic body, is applied by a dipping method, dried and baked, and in order of nickel plating and solder plating in order to make the external electrode a solder plated terminal. The external electrode terminals are formed by plating.

[0007]

However, when the external electrodes 3 are formed by the dipping method, the holes 4 are generated in the external electrodes 3 due to entrainment of air.
In the later plating step, the plating solution penetrates through the thin portion of the external electrode 3 having the holes 4 and the plating solution penetrates into the internal electrode layer 2, resulting in delamination (delamination). ) Is caused.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the generation of voids in the external electrodes of a multilayer ceramic capacitor and a multilayer chip inductor, to reduce the occurrence of delamination of the element, and to form a highly reliable external electrode. An object of the present invention is to provide a method for manufacturing a capacitor and a multilayer chip inductor.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by spraying a paste containing metal powder in which a low-resistance metal is dispersed in an organic vehicle in the form of a spray, drying, and drying the paste.
A method for manufacturing a multilayer ceramic capacitor and a multilayer chip inductor, wherein an external electrode is formed by baking.

According to the present invention, a dielectric ceramic layer and an internal electrode layer made of a low-resistance metal are alternately laminated, and an external electrode made of a low-resistance metal is provided on a laminate in which protective layers are formed above and below in the laminating direction. A method of manufacturing a multilayer ceramic capacitor, comprising: spraying a low-resistance metal paste on an end face of an outlet of an internal electrode layer in a spray form, drying and baking to form an external electrode. Is the way.

[0011] The present invention also provides a method for connecting a conductor pattern printed on a magnetic layer, laminating the magnetic layer to form a helical coil inside the magnetic body, and exposing the tip of the conductor pattern to the side surface of the magnetic layer. A multilayer chip inductor connected to an external electrode terminal, wherein a low-resistance metal paste is sprayed on the end face of the opening of the conductor pattern in a spray shape, and dried and baked to form an external electrode terminal. It is a manufacturing method of.

According to the method for manufacturing a multilayer ceramic capacitor and a multilayer chip inductor of the present invention, defects due to voids in external electrodes are eliminated, and a plating solution does not enter inside during a later plating step. Delamination failure can be reduced, and a highly reliable multilayer ceramic capacitor and multilayer chip inductor can be obtained.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with respect to a method for manufacturing a multilayer ceramic capacitor and a multilayer chip inductor.

(Embodiment 1) In Embodiment 1 of the present invention, a multilayer ceramic capacitor will be described. First, a powder having a lead (Pb) -based perovskite structure and a particle diameter of 1 micron or less is used for a ferroelectric ceramic serving as a base material of a capacitor, and silver (Ag) is used for an internal electrode layer.
An alloy powder having a ratio of palladium (Pd) of 70:30 was used.

An organic binder of polyvinyl butyral and ethyl cellosolve are added to the dielectric ceramic powder.
An organic solvent of butyl carbitol was mixed and dispersed to obtain a ceramic slurry.

The internal electrode paste is prepared by adding the mixed powder having the above-mentioned mixing ratio to an organic vehicle using ethyl cellulose as an organic binder and α-terpineol and stearic acid as an organic solvent, and kneading with a three-roll mill. used.

The film was adjusted by a doctor blade method so as to have a thickness of 18 μm on the carrier film after drying. Then, on the green sheet, the internal electrode paste was formed into a strip pattern of 10 mm × 3 mm by 2 μm.
Printed to thickness.

After the green sheet thus produced is cut, 75 layers are laminated so as to form a counter electrode structure of a capacitor, a protective film having a thickness of 250 μm is sandwiched between the layers, and after thermocompression bonding with a hot press, individual elements are formed. Cut into shapes.

After removing the binder at 400 ° C. for 7 hours,
It was fired at 900 hours for 4 hours to obtain a sintered body.

On the other hand, the external electrode is made of 100% silver as a metal.
Was added to an organic vehicle using ethyl cellulose as an organic binder and α-terpineol and kerosene as an organic solvent, a glass frit was added, and the mixture was kneaded with three rolls.

Then, as shown in FIG. 1, an external electrode paste was applied to the end face of the outlet 7a of the internal electrode layer of this sintered body by a spray nozzle 5 of a spray device to a thickness of 150 μm.
Adjust the injection pressure, distance, and paste viscosity with the goal of
External electrode paste was sprayed.

At this time, the side faces other than the end face of the outlet 7a for the internal electrode layer were masked by a masking jig 6 as shown in FIG. After spray coating, drying and baking were performed, and a multilayer ceramic capacitor element 7 of the present invention was obtained through a plating step.

For comparison with the monolithic ceramic capacitor according to the present invention, an external electrode prepared by dipping according to a conventional method was also prepared, and 100 sections were observed by polishing, and the porosity of the external electrode was calculated. Was inspected. In addition, 10,000 samples were prepared and immersed in a plating solution for an arbitrary time to accelerate the occurrence of delamination, thereby comparing the effects. Table 1 shows the results.

[0024]

As can be seen from Table 1, compared to the conventional product,
It can be seen that the product of the present invention improves the delamination occurrence rate of the ceramic capacitor.

(Embodiment 2) Embodiment 2 of the present invention will be described in detail with reference to an example of manufacturing a multilayer chip inductor.

First, an insulating magnetic powder and an organic binder of polyvinyl butyral and an organic solvent of ethyl cellosolve and butyl carbitol were mixed and dispersed with the magnetic powder to form a slurry.

The slurry is dried by a doctor blade method and adjusted to a thickness of 200 to 600 μm on a carrier film to form a long green sheet of an insulating magnetic material, which is cut into a predetermined size. .

Hereinafter, as shown in the process diagram of FIG. 3, the internal conductor 21 is screen-printed in a predetermined pattern with an Ag paste on the obtained green sheet 11, and dried.
The insulating magnetic slurry is screen-printed on the magnetic layer 12 so that the internal conductor 21 is exposed, leaving a portion of the internal conductor 2 connected to the next layer in the window-like through hole 41.
Print and dry.

Next, the internal conductor 21 is printed in a predetermined pattern so as to be connected to the connection portion of the internal conductor.
dry.

Similarly, lamination printing is repeated one after another by a predetermined number to form a spiral coil with the internal conductor, and both ends of the formed coil are formed so as to be exposed to the outside.

The green sheet 11 as the upper insulating magnetic layer is pressed on the laminated printed body by hot pressing to form an unfired laminated body.

The laminate thus manufactured was cut into a chip shape.

After removing the binder at a predetermined temperature and for a predetermined time, the unfired chips were fired at 600 ° C. for a predetermined time to obtain a sintered body.

On the other hand, silver is used as a metal for the external electrode.
% Powder was put into an organic vehicle using ethyl cellulose as an organic binder and α-terpineol and kerosene as an organic solvent, and a glass frit was added thereto and kneaded with a three-roll mill.

The injection pressure, distance, and paste viscosity of the external electrode paste were adjusted to a thickness of 150 μm with a spray device on the end surface of the sintered body, which was the internal conductor outlet, to spray the external electrode paste. Was done.

At this time, masking as shown in FIG. 1 was applied to the side surfaces other than the end surface of the internal electrode outlet.

After spray coating, drying and baking,
Through a plating process, a multilayer chip inductor according to the present invention was obtained.

For comparison with the multilayer chip inductor according to the embodiment of the present invention, an external electrode manufactured by dipping according to a conventional method is also prepared, and each of the external electrodes is polished.
A cross section of 00 pieces was observed, and the occurrence rate of voids in the external electrode was inspected. In addition, 10,000 samples were prepared and immersed in a Ni plating solution for an arbitrary period of time to accelerate the occurrence of delamination, thereby comparing the effects. Table 2 shows the results.

[0040]

[0041]

As described above, the generation of voids in the external electrodes of the multilayer ceramic capacitor and the multilayer chip inductor is suppressed, the delamination failure of the element is reduced, and the external electrodes having excellent reliability are formed. To provide a method for manufacturing a multilayer ceramic capacitor and a multilayer chip inductor.

[Brief description of the drawings]

FIG. 1 is a perspective view showing masking when spraying is performed.

FIG. 2 is an explanatory diagram showing holes formed by entrainment of air in external electrodes formed by a dipping method. FIG. 2A is an explanatory view showing holes confined therein. FIG. 2B is an explanatory diagram illustrating holes that are holes on the outside.

FIG. 3 is a view showing a stacking process of the multilayer chip inductor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric ceramic layer 2 Internal electrode layer 3 External electrode 4 Void 5 Spray nozzle 6 Masking jig 7 Ceramic capacitor element 7a Outlet 11 Green sheet 12 Magnetic layer 21 Inner conductor 41 Through hole

Claims (2)

[Claims] 1. A laminated structure in which dielectric ceramic layers and internal electrode layers made of a low-resistance metal are alternately laminated, and an external electrode made of a low-resistance metal is provided on a laminated body in which protective layers are formed above and below in the laminating direction. What is claimed is: 1. A method for manufacturing a ceramic capacitor, comprising spraying a low-resistance metal paste onto an end face of an outlet of an internal electrode layer, drying and baking to form external electrodes. 2. A conductor pattern printed on a magnetic layer is connected, the magnetic layers are stacked to form a spiral coil inside the magnetic body, and a tip of the conductor pattern is exposed on a side surface of the magnetic layer. In a multilayer chip inductor connected to a terminal, a low-resistance metal paste is sprayed on an end face of an outlet of the conductor pattern in a spray shape, and dried and baked to form an external electrode terminal.