JPS6029209B2 - Manufacturing method of multilayer ceramic capacitor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a multilayer ceramic capacitor,
In particular, the present invention relates to a method for producing an electrode layer and a ceramic sheet, and a method for constructing a laminate.

Conventionally, this type of capacitor has been constructed horizontally as shown in FIGS. 1 and 2.

In Fig. 1, 1 is a ceramic sheet laminated part before firing with electrodes formed at predetermined positions on the surface, and 2 is a blank ceramic sheet part made by laminating the required number of unfired ceramic sheets on which electrodes are not formed. It is. The blank ceramic sheet parts 2 are arranged above and below the ceramic sheet laminated part 1 to reinforce it. Each ceramic sheet of the ceramic sheet laminated portion 1 is obtained by coating a base material with a dielectric slurry by a doctor blade method, and after drying, a paste-like electrode material is applied to the surface of the base material. FIG. 2A is a sectional view of the ceramic sheet 4 formed by coating the base material 3 with a dielectric slurry. When coating the dielectric material, unevenness occurs on the surface of the ceramic sheet 4, which has a degree of spatial freedom, so the thickness of the ceramic sheet is usually not uniform and has variations. Dielectric bran generally consists of (a) a raw material powder that becomes a ceramic dielectric after firing, (b) a binder for mutually bonding the raw material powder, (c) a plasticizer that gives appropriate bending flexibility to the ceramic sheet, and (d) an adjustment of the bran viscosity. and a dispersant to uniformly disperse them.

When a mud acid having such a composition is coated on the surface of the base material, each fine particle in the mud simulator is affected by gravity, and the raw material powder fine particles having a specific gravity shift downward. Therefore, the formed ceramic sheet 4 has a higher density as it approaches the base material, and a lower density as it goes upward. As mentioned above, the surface of the ceramic sheet 4 is uneven and has a low density.
Coating and forming a paste-like electrode material on the ceramic sheet 4 causes variations in the thickness of the electrode, and also causes the electrode to be fixed to the surface of the ceramic sheet 4.

For this reason, the volumetric shrinkage of the ceramic sheet and the electrodes that occurs during firing increases the adverse effects such as wire breakage, cracks, and electrode peeling caused by the difference in shrinkage rates between the two. Furthermore, since the electrodes formed on the surface of the ceramic sheet 4 have a predetermined thickness, when stacked as shown in FIG. 1, the stacked thickness differs between the overlapping part of the electrodes and the part of only the ceramic sheet. For this reason, the magnitude of the pressure applied when pressurizing the laminate to make the thickness uniform was partially different. Therefore, in the cutting process to divide the laminate into capacitor chips, the mechanical strength of the low-density parts, where the applied pressure is small, is weak, so the displacement due to the pressure of the cutting blade becomes large, causing cracks and electrode peeling.
An object of the present invention is to provide a multilayer ceramic capacitor that is inexpensive and of excellent quality. The manufacturing method of a multilayer ceramic capacitor according to the present invention involves forming an electrode layer in advance at a predetermined position on the surface of the base material on which the ceramic sheet is to be formed in the formation of a ceramic sheet having electrodes, and then applying a doctor blade method on the electrode layer to form a ceramic sheet. The method is characterized in that a ceramic sheet is formed by applying muddy acid onto a surface, drying it, and then peeling it off to form a sheet, and then peeling this sheet together with the electrode layer from the surface of the base material. Alternatively, in the method for manufacturing a multilayer ceramic capacitor according to the present invention, an electrode layer is formed in advance at a predetermined position on the surface of a base material on which a ceramic sheet is to be formed, and then a ceramic sheet is formed on the electrode layer by a doctor blade method. This method is characterized by having a step of peeling the ceramic sheet from the surface of the base material. Furthermore, it is characterized in that the ceramic sheets with electrode layers and the ceramic sheets without electrode layers are stacked alternately. Furthermore, the multilayer ceramic capacitor according to the present invention is characterized in that the internal electrode layer is embedded in a ceramic sheet supporting the internal electrode layer so that the ceramic sheet surface and the surface of the internal electrode layer are flush with each other. do. FIG. 3 shows a laminated ceramic capacitor according to an embodiment of the present invention, in which each ceramic sheet constituting the ceramic sheet laminated portion 1 is formed with an electrode 5 embedded in the surface of the ceramic sheet 4. As shown in FIG.

That is, as shown in FIG. 4, the electrodes 5 are formed in advance on the surface of the base material 3 at predetermined positions, and then the base material 3 is coated with silkworm body slurry so as to cover the electrodes 5. , the electrode 5 is embedded in the surface of the ceramic sheet 4. Such a ceramic sheet 4 and electrode 5
After drying, if both are peeled off from the surface of the base material 3, a constituent sheet of the ceramic sheet laminated portion 1 as shown in FIG. 3 is obtained. If necessary, it is a good idea to apply silicone oil or the like to the surface of the base material beforehand in order to separate the sheet from the base material. In the constituent sheet obtained in this way, since the electrode 5 is formed on the surface of the ceramic sheet 4 close to the base material 3, that is, the high-density surface,
It is possible to greatly reduce the occurrence of cracks and distortions on the electrode surface during firing of the ceramic sheet. The above-described laminate of the present invention shown in FIG. 3 is obtained by stacking these electrode-embedded ceramic sheets using a general method. However, if necessary, a construction method such as the laminate shown in FIG. It can also be used. Fifth
In the figure, 1 is a ceramic sheet laminated part, and 2 is a blank ceramic sheet part. Blank ceramic sheets 9 having no electrodes formed on their surfaces are inserted and laminated between the electrode-embedded ceramic sheets 8 described above constituting the ceramic sheet laminated section 1 . Another construction method of the present invention as shown in FIG. 5 is suitable when the electrode embedded ceramic sheet 8 is extremely thin as shown in FIG.

That is, if the viscosity of the dielectric slurry is low due to the composition of the dielectric slurry and therefore the thickness of the ceramic sheet 4 cannot be made sufficiently thicker than the thickness of the electrode 5, the electrode 5 may be covered locally. There will be places where it is impossible to do so. The same is true when, on the surface, the electrode 5 appears to be covered with the ceramic sheet 4, but there are some very thin parts. The blank ceramic sheet 9 shown in FIG. 5 is used in such a case, and can form a desired thickness of the ceramic sheet.

If the construction method as shown in FIG. 5 is adopted for an electrode-embedded ceramic sheet having a normal thickness, it is of course possible to realize high reliability of the capacitor.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a conventional method of manufacturing a multilayer ceramic capacitor, and FIG. 2 is a diagram illustrating a method of forming a ceramic sheet by the conventional method. 3 and 4 are cross-sectional views showing one embodiment of the manufacturing method of the present invention, and FIGS. 5 and 6 are cross-sectional views showing other embodiments of the present invention. Symbols in the figure: 1...Ceramic sheet laminated part, 2...Blank ceramic part, 3...
...Base Village, 4. ...Ceramic sheet, 5
... Electrode, 6 ... Printing table, 7 ...
Ceramic sheet, 8... Electrode embedded ceramic sheet, 9... Blank ceramic sheet. Figure 2: Figure 2: Disciple Figure: Disciple Figure: Figure 2: Figure 2

Claims (1)

[Claims] 1 Form an electrode layer on a predetermined portion of the surface of the base material on which the ceramic sheet is to be formed, form a ceramic sheet on the surface of the base material including the electrode layer by a doctor blade method, and apply the ceramic sheet together with the electrode layer to the base material. A method for manufacturing a multilayer ceramic capacitor, comprising a step of peeling it off from the surface of the material.