JPH088200B2 - Method for manufacturing ceramic electronic component - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a ceramic electronic component in which an electrode is formed by applying or printing a conductive paste on a ceramic green sheet and baking the conductive paste, ,
The present invention relates to an improved conductive paste printing process.

[Conventional technology]

A multilayer ceramic electronic component such as a multilayer capacitor, a multilayer substrate or an LC chip is configured by using a ceramic sintered body in which a plurality of internal electrodes are configured. Conventionally, the following method has been used to manufacture this ceramic sintered body.

First, a ceramic slurry is formed on a base film by a doctor blade method, dried and then peeled from the base film to obtain a ceramic green sheet. Next, the obtained ceramic green sheet is punched into a predetermined size. A conductive paste is printed on one main surface of the punched ceramic green sheet by a screen printing method so as to have a predetermined internal electrode shape, and dried. A predetermined number of one or more kinds of ceramic green sheets on which the conductive paste is printed are prepared, and they are laminated while aligning them according to a predetermined stacking method. The obtained laminated body is placed in a mold, pressure-bonded in the thickness direction, and then fired to obtain a ceramic sintered body having internal electrodes inside.

[Technical problem to be solved by the invention]

However, in the above conventional manufacturing method, since the screen printing method is used for printing the conductive paste, there are various problems as described below.

For example, consider the case where the conductive paste 2 is printed on a rectangular area on the ceramic green sheet 1 as shown in the plan view of FIG. In this case, in the conventional screen printing method, the dimensions a and b of the conductive paste 2 and the positions where the conductive paste 2 is printed tend to vary by about ± 15 μm. As a result, when such a conductive paste 2 is used to form a multilayer capacitor, for example, the obtained capacitance tends to vary among the obtained products.

Moreover, the variations in the print size and position are not constant, and tend to increase with time. It is considered that this is because the mesh screen used for screen printing is deformed as it is used.

In the screen printing method, as shown in FIG.
Since the rubber squeegee 3 is moved in the direction of the arrow and printing is performed while scraping the conductive paste 4 on the screen mesh 5, the coating thickness tends to be thicker with a small internal electrode (printing area). On the other hand, large ones tend to be printed lightly. In addition, 6 shows a base film.

Therefore, in order to reliably obtain an internal electrode having a constant thickness, it is necessary to strictly control the force for pressing the squeegee 3 against the screen mesh 5 and the amount and viscosity of the conductive paste 4. Further, the coating thickness of the conductive paste 4 tends to be thin with time. This change in coating thickness over time is also considered to be due to the deformation and settling of the screen mesh.

If the coating thickness of the conductive paste 4 is thicker than a predetermined thickness, it may cause delamination when the ceramic laminate is sintered. Therefore, in order to improve the yield, it is necessary to control the conditions for screen printing extremely strictly.

Further, in the screen printing method, the area of the mesh openings of the screen mesh 5 is generally printed larger than the area of the mesh openings. Therefore, even if the openings of the screen mesh are designed according to the internal electrodes having a desired size, it is difficult to obtain the designed capacitance.

As described above, the conventional conductive paste printing method has a very big problem that it is impossible to prevent a considerable amount of print misalignment and the print misalignment increases with time due to deterioration of the screen mesh. . Therefore, in ceramic electronic components that are becoming smaller, variations in the characteristics such as the acquisition capacitance due to the above-described printing shift cannot be ignored.

An object of the present invention is to provide a method of manufacturing a ceramic electronic component which can improve the printing accuracy of the conductive paste and therefore can manufacture a ceramic electronic component with less variation in characteristics, and which can easily manage the printing process. Especially.

[Means for solving technical problems]

The present invention provides a conductive paste on a ceramic green sheet after printing the conductive paste on the film,
Alternatively, in a method of manufacturing a ceramic electronic component, which comprises a step of directly printing a conductive paste on a ceramic green sheet, and a step of forming an electrode by baking the conductive paste applied or printed on the ceramic green sheet, It is characterized by having a configuration.

That is, the printing of the conductive paste is performed by the gravure printing method using a rigid roll having at least one recess corresponding to the printed shape of the conductive paste on the outer peripheral surface.

[Action]

Since the conductive paste is printed by the gravure plate composed of a rigid roll, deformation or settling such as screen mesh does not occur. Therefore, the accuracy of the printing shape and the accuracy of the printing position of the conductive paste can be effectively improved. Further, since the rigid roll is used, the shape of the plate does not deform with time, and thus the printed shape and the printing position hardly change with time.

Since the gravure plate and the film or the ceramic green sheet are brought into contact with each other for printing, a dimensional difference is unlikely to occur between the shape of the concave portion which becomes the plate mold and the shape of the printed conductive paste. Therefore, it is possible to accurately form the electrode having the size as designed. Similarly, the thickness of the conductive paste coating is unlikely to change depending on the size of the electrode.

[Explanation of Examples]

Embodiments applied to a method for manufacturing a multilayer capacitor will be described below with reference to the drawings.

First, as shown in FIG. 4, a ceramic slurry is formed into a film by a doctor blade method or the like on a long base film 11 made of synthetic resin such as polyester or polypropylene, and dried to form a long film. A ceramic green sheet 12 is obtained.

Next, the ceramic green sheet 12 is peeled off from the base film 11. Ceramic green sheet 12
When the thickness of is as thin as 1 μm to 30 μm,
Because the strength is insufficient, it does not peel off from the base film 11,
The following steps are carried out.

Next, the obtained long ceramic green sheet 12
The conductive paste is printed on the one main surface using the printing position shown in FIG. In FIG. 1, reference numeral 13 indicates a supply roll, around which a long ceramic green sheet 12 is wound. The ceramic green sheet 12 is provided with a guide roller 14 by rotating the supply roll 13 in the direction of the arrow shown.
And is fed between the rigid roll 15 and the backup roll 16.

The rigid roll 15 is made of a rigid material such as metal, and is formed into a cylinder (column) shape as shown in FIG. A plurality of concave portions 15a are formed on the outer peripheral surface of the rigid roll 15 at predetermined intervals. The recess 15a is formed to have a planar shape that matches the printed shape of the conductive paste, and is provided to form a gravure plate. In FIG. 5, a plurality of recesses 15a arranged at appropriate intervals in the circumferential direction of the rigid roll 15 are arranged in three rows in the axial direction of the rigid roll 15.

Returning to FIG. 1, the rigid roll 15 is positioned such that a part of its outer peripheral surface is immersed in the conductive paste 18 stored in the tank 17. Further, the rigid roll 15 is rotationally driven in the direction of the arrow shown in the figure, whereby the conductive paste 18 attached to the outer peripheral surface is carried to the backup roll 16 side. A scraping blade 19 is brought into contact with the outer peripheral surface of the rigid roll 15 in order to remove the conductive paste attached to the outer peripheral surface other than the recess 15a.

As shown in FIG. 1, the ceramic green sheet 12 is
It is passed between a rigid roll 15 and a backup roll 16. At this time, the backup roll 16 is a rigid roll 15
Then, the conductive paste is gravure-printed on the lower surface of the ceramic green sheet 12 by the rigid roll 15 with a predetermined pressure. After that, ceramic green sheet
The material 12 is dried by the heater 21 after passing through the guide roll 20 and wound on the winding reel 22.

FIG. 6 shows a plan view of the shape of the conductive paste printed by the gravure printing method as described above. On the lower surface of the ceramic green sheet 12, the recess 15a of the rigid roll 15 is formed.
As shown in FIG. 5, the conductive paste 23 is printed in a rectangular shape at a predetermined interval. In this case, since the rigid roll 15 is printed by contacting the ceramic green sheet 12, the planar shape of each conductive paste 23 is
The shape of the recess 15a is exactly matched with the plane shape. That is, in the screen printing method, it was apt to be printed wider than the openings of the mesh screen, but when the rigid roll 15 is used, the conductive paste has a shape that exactly matches the shape of the concave portion that is the plate mold. 23 can be printed.

Moreover, since the rigid roll 15 is used, the accuracy of the printing position is improved, and deterioration over time is unlikely to occur. That is, in the screen printing method, the print shape and the printing position changed with time due to the deformation of the screen mesh during repeated printing, but in the gravure printing method using the rigid roll, Change in print shape and print position with time does not occur. Therefore, since it is possible to print using the same rigid roll 15 semipermanently,
Printing costs are also reduced.

Furthermore, regarding the coating thickness of the conductive paste 23,
It can be kept constant regardless of the size of the area of 15a.
Therefore, management of printing conditions is easy.

The process after printing the conductive paste is performed in the same manner as the conventional method for manufacturing a ceramic electronic component. That is, for example, the ceramic green sheet 12 wound on the take-up reel 22 is punched into a predetermined size. Next, a predetermined number of the ceramic green sheets on which the conductive paste is printed are stacked while positioning them according to a predetermined stacking method to obtain a ceramic laminate. The obtained ceramic laminated body is pressure-bonded in the thickness direction, cut if necessary, and then fired to obtain a ceramic sintered body having internal electrodes based on the conductive paste 23 therein. Finally, a ceramic electronic component can be formed by appropriately forming external electrodes on the outer peripheral surface of the obtained sintered body.

Since the above embodiment is applied to the manufacture of a multilayer capacitor, it suffices to prepare only the ceramic green sheet 12 printed with the rectangular conductive paste 23 as shown in FIG. In some cases, it may be necessary to form internal electrodes of various planar shapes. In that case, a conductive paste having a planar shape corresponding to various internal electrode shapes may be printed by the gravure printing method, and a plurality of ceramic green sheets may be laminated according to a predetermined stacking method.

Further, in FIG. 5, one concave portion 15a is formed for one printed pattern of the internal electrode forming conductive paste,
As shown in FIG. 8, one electrode printed shape may be formed by a plurality of recesses 15b. The shape and depth of each recess 15b may be the same or different. These gravure plate shapes are appropriately selected depending on the film thickness after printing.

Further, the conductive paste contains a solvent, which may cause a problem of swelling of the ceramic green sheet due to the solvent. In this case, the ceramic green sheet
As shown in FIG. 7 (a), the conductive resin 23 is not directly gravure-printed on the 12, and the synthetic resin film is subjected to a release treatment.
The conductive paste 25 is printed and dried on the release-treated surface of 24 by the gravure printing method described above, and then, FIG. 7 (b).
As shown in, by thermal transfer ceramic green sheet
The conductive paste 25 may be transferred onto the surface 12. In this case, in the printing apparatus shown in FIG. 1, the ceramic green sheet 12 is replaced with the synthetic resin film 24 which has been subjected to the above-described release treatment.

Further, a conductive paste is gravure-printed on the synthetic resin film in the same manner as in the above embodiment, dried, and then a ceramic slurry is formed into a sheet on the upper surface by a doctor blade method or the like, and then peeled from the synthetic resin film. Thus, a conductive paste may be applied to the main surface of the ceramic green sheet on the synthetic resin film side.

The rigid roll used in the manufacturing method of the present invention may be made of a material other than metal. For example, it may be made of ceramics or glass, or may be made of synthetic resin as long as it is a rigid material that does not easily change its shape with time.

As the ceramic electronic component to which the manufacturing method of the present invention is applied, in addition to multilayer capacitors, ceramic multilayer substrates, LC
Various things can be mentioned, such as filters, capacitor networks and inductance chips.

〔The invention's effect〕

As described above, in the present invention, the conductive paste is printed by the gravure printing method using the rigid roll. Since it is a gravure printing method, the rigid roll and the ceramic green sheet or film are printed in contact with each other, so that there is no dimensional difference between the recessed portion which is the plate and the printed conductive paste. Therefore, by forming a recess corresponding to the shape of the electrode, it is possible to surely form an electrode having a desired size, and it is possible to realize the capacity as designed.

Further, since a rigid roll is used, the shape of the concave portion, which is a plate, is unlikely to deteriorate with time. Therefore, not only can the conductive paste be printed on the correct size and position,
The print size and print position do not change over time. Not only that, but you can print semi-permanently while maintaining accuracy.
It is also possible to reduce the printing cost.

Furthermore, when printing a conductive paste using the conventional screen printing method, the emulsion is applied to the screen mesh, and the solvent in the conductive paste dissolves the emulsion, which may deteriorate the printing accuracy. However, since the present invention does not use such an emulsion, the solvent in the paste can be arbitrarily selected.

[Brief description of drawings]

FIG. 1 is a schematic sectional view for explaining a process of printing a conductive paste in one embodiment of the present invention, and FIG. 2 is a plan view of a ceramic green sheet and a conductive paste used for manufacturing a multilayer capacitor. FIG. 3 is a partially cutaway sectional view for explaining a conductive paste applying step by a screen printing method, and FIG. 4 is a partially cutaway perspective view showing a state where a ceramic green sheet is formed on a base film, Fig. 5 is a perspective view of a rigid roll, No. 6
The figure is a plan view showing a state in which the conductive paste is printed on the ceramic green sheet by gravure printing, and FIGS. 7A and 7B show the state in which the conductive paste is printed on the synthetic resin film by gravure printing. 8 is a perspective view showing another example of the rigid roll, for explaining the process of transferring the conductive paste onto the ceramic green sheet. In the figure, 12 is a ceramic green sheet, 15 is a rigid roll, 15a is a recess, 18 and 23 are conductive pastes, and 24 is a film.

Claims (1)

[Claims] 1. A step of printing a conductive paste on a film and then applying the conductive paste on a ceramic green sheet, or directly printing the conductive paste on the ceramic green sheet, and thereafter applying the conductive paste on the ceramic green sheet. Or a method of manufacturing a ceramic electronic component, which comprises a step of forming an electrode by baking a printed conductive paste, wherein the conductive paste is printed by forming at least one recess corresponding to the printed shape of the conductive paste on the outer peripheral surface. A method of manufacturing a ceramic electronic component, characterized by performing a gravure printing method using a rigid roll provided.