JPS5823427A - Method of producing ceramic condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention relates to a method for making a ceramic capacitor.
In particular, the present invention relates to a method for manufacturing a large-capacity ceramic capacitor in which the thickness of the dielectric material (2) is extremely thin by being reinforced by mechanical reinforcement means.

To increase the capacitance of ceramic capacitors,
It is necessary to increase the overlapping area of a pair of electrodes forming a capacitor and to decrease the distance between each electrode. However, since increasing the external size violates the goal of miniaturization, the capacitance is generally increased by reducing the distance between the electrodes as much as possible. However, if the electrode distance t is made smaller, the mechanical strength of the ceramic capacitor becomes smaller, so there is naturally a limit to reducing the electrode distance t.

The technology to meet this demand is Utility Model 56-2
There is a technique disclosed in No. 6942 (Utility Application No. 107323/1983). 1 and 2 are diagrams showing the structure of this interesting prior art ceramic capacitor, with FIG. 1 being a plan view and FIG.
It is a sectional view along II. The ceramic capacitor 1 shown in the first WA and FIG. 2 has the other electrode 3 forming the capacitor inside a ceramic body 8 which has one electrode 4 forming the capacitor on one surface. That is, a capacitor is constituted by the ceramic layer 8A and a pair of opposing electrodes 3.4 using this as a dielectric layer. The other electrode 3 has a ceramic layer 8B on its back surface.
It is electrically connected to an extraction electrode 9 provided on the outer surface of the ceramic layer 8B, that is, on the other surface of the ceramic body 8, via a through hole 10. Therefore, ceramic layer 8B
Since the presence of the ceramic layer 8A provides mechanical strength, it is possible to make the thickness of the ceramic layer 8A as a dielectric layer, that is, the electrode open side - extremely small.

However, in the ceramic capacitor 1 shown in FIGS. 1 and 2, each conductive pattern that becomes the electrode 4 and the extraction electrode 9 is formed by printing, so it is extremely difficult to manufacture a large quantity of the ceramic capacitor 1 at one time. It had the disadvantage of being difficult. In addition, since printing means is used as the material for forming these conductive patterns, expensive silver or silver-palladium must be used, which has the disadvantage of increasing the manufacturing cost of ceramic capacitors. Was.

Therefore, the main object of the present invention is to provide a method that eliminates the above-mentioned drawbacks and enables mass production of small-sized, large-capacity ceramic capacitors efficiently and at low cost.

In summary, the present invention includes a first ceramic green sheet on which one electrode pattern constituting a capacitor is formed, and a second ceramic green sheet on which a through hole for taking out an electrode is formed.
A sintered body is formed by overlapping and sintering ceramic green sheets or ceramic green molded bodies, and the entire sintered body is plated with a conductive material, and then the plated parts on the sides of the sintered body are plated with a conductive material. This is a method of manufacturing ceramic capacitors by removing.

The above objects and other objects and features of the present invention will become more apparent from the following detailed description with reference to the drawings.

3 to 8 are perspective views for explaining one embodiment of the present invention. The following description will be made with appropriate reference to these drawings.

FIG. 3 is a perspective view for explaining the process of forming one electrode pattern for a capacitor on one side of the first ceramic green sheet.

A first ceramic green sheet 11 having a thickness of, for example, 30 μm is prepared, and one electrode pattern 13 for a plurality of capacitors is formed on one surface thereof by thick film forming means such as printing. Each electrode pattern is
For example, it is composed of silver or silver-palladium, but may be composed of various other conductive materials.

FIG. 4 is a perspective view for explaining the process of forming the electrode extraction through-hole 14 in the second ceramic green sheet 12. For example, a ceramic green sheet of approximately 100 μm is prepared as the second ceramic green sheet 12, and a plurality of through holes 14 for taking out the electrodes are formed, for example, by punching. The number of electrode extraction through holes 14 does not necessarily have to match the number of electrode patterns 13 on each side shown in FIG.

That is, a plurality of electrode extraction through holes 14 may be formed so as to match one electrode pattern 13 .

FIG. 5 is a perspective view for explaining the process of mating the first ceramic green sheet and the second ceramic green sheet. On the first ceramic green sheet 11 on which each one of the electrode patterns 13 is formed,
The second ceramic green sheets 12 in which the through holes 14 for taking out the electrodes are formed are overlapped. At this time, each electrode extraction through hole 14 is connected to each one of the electrode patterns 13.
are placed on top of each other. however,
Each electrode extraction through hole 14 is connected to each one of the electrode patterns 1
It is not necessary to position the electrode pattern 13 exactly in the center of the electrode pattern 13, but it is only necessary to position the electrode pattern 13 on one side of the electrode pattern 13. especially,
When a plurality of through-holes 14 are formed for a single electrode pattern 13, it is extremely easy to do so because it is only necessary to position one of the through-holes 14 above the electrode pattern 13. positioning is achieved.

Next, the superposed first ceramic green sheet 11 and second ceramic green sheet 12 are advanced in the direction of arrow X in FIG.
sent to the prison. The first and second ceramic green sheets 11 passed through a pressure of 0-16.16
．． 12 are brought into close contact with each other by applying pressure. Chicken 1 and second ceramic green sheet 11 in close contact with each other
12 is cut in a direction perpendicular to the direction of arrow X in FIG. 5, that is, in a direction perpendicular to the traveling direction of the first and second ceramic green sheets 11.12.

FIG. 6 is a perspective view showing this cutting process. This cutting is performed by moving the cutting blade 15 in the direction of arrow Z in FIG. This cutting forms a ceramic body of appropriate size. By sintering this ceramic body, a sintered body 1 as shown in FIG.
7 is formed.

The sintered body 17 is electrolessly plated with a conductive material such as nickel or copper, and then about 30 minutes
The plating layer is fixed by heating at 0°C. By this electroless plating, the entire sintered body 17 shown in FIG. 7 is coated with a conductive material such as nickel or copper.

Next, the sintered body 17 shown in FIG. 7 is cut with a scriber slice of the same piece. By this scriber slice cut, side surfaces 18.19, 20.2 of the sintered body 17 are cut.
1, the end faces are exposed and the plating walls fixed to each side 18, 19, 20, 21 are removed. Note that this plating layer may be removed by various other polishing or cutting processes. Also, by removing this plating (■), the snow pattern 13 is changed to 11ffi18, 19, 20
It is preferable not to be exposed to 21 degrees, but even if exposed, the park will not open. This is because the upper and lower surfaces of the sintered body 17 cannot be electrically connected by removing the plating layer.

Next, the sintered body 17 from which the plating on each side surface 18, 19, 20, 21 has been removed is cut into electrode patterns 13 on each side. A ceramic capacitor 22 thus obtained is shown in FIG.

In this example, each one of the electrode patterns 13 was cut after sintering, but it is also possible to cut each one of the electrode patterns 13 into units shown in FIG. 8 before sintering. good.

9 and 10 are diagrams showing the structure of the ceramic capacitor obtained by this example, and FIG.
The figure is a plan view, and FIG. 10 is a cross-sectional view taken along line x-x in FIG. 9. The ceramic capacitor 22 obtained by this embodiment shown in FIGS. 9 and 10 has one electrode 23 for the capacitor constituted by one electrode pattern 13. One electrode 23 is formed in a ceramic body 28, and the other electrode 23 forms a capacitor via a ceramic layer 28B as a dielectric material 2 made of the first ceramic green sheet 11.
It is opposite to 4. That is, in this ceramic capacitor 22, a capacitor is constituted by a ceramic layer 28B and a pair of electrodes 23 and 24 facing each other using this as a dielectric. The back surface of one electrode 23 for a capacitor formed inside the ceramic body 28 is
It is in contact with the electrode extraction through hole 14, and a conductive material is formed as a thin film on the inner peripheral surface of the electrode extraction through hole 14 by electroless plating, and the ceramic 1
An extraction electrode 29 formed on the other surface of 128, that is, the surface opposite to the surface on which the other electrode 24 for the capacitor is formed.
It is connected to That is, one electrode 23 for the capacitor is electrically connected to an extraction electrode 29 formed on the other surface of the ceramic body 28. In the ceramic capacitor 22 shown in FIGS. 9 and 10, the distance t between the electrodes is determined by the thickness of the ceramic layer 28B, so the capacitance can be increased by reducing the thickness of the ceramic 1128B. becomes. At this time, since the ceramic layer 28A is present on the back surface of one electrode 23 for the capacitor, the ceramic layer 28A
Even if the thickness of B is made as thin as possible, the mechanical strength of this capacitor 22 can be maintained at a sufficient level. This insect is similar to the ceramic capacitor obtained in the prior art shown in FIGS. 1111 and 2. However, in the ceramic capacitor 22 obtained in this embodiment, the other electrode 24 and the extraction electrode 29 for the capacitor are formed by electroless plating of a conductive material such as nickel or copper. Since conductive materials such as nickel or copper are extremely inexpensive compared to silver used in the prior art, the ceramic capacitor 22 obtained by this example
can be manufactured very cheaply. Further, in electroless plating, there is no need to increase the diameter of the through hole 14 shown in the fourth WJ. That is, even if the diameter of each through hole 14 is minute, a conductive material such as nickel or copper can easily enter therein. Therefore, since the diameter of the through hole 14 can be made smaller, it is possible to further increase the reinforcing effect of the ceramic layer 28A. Furthermore, in this embodiment, by electroless plating the entire sintered body 17 in large quantities at once,
Since the electrode 24 and the extraction electrode 29 can be formed at the same time, extremely ml! It has excellent I properties.

FIGS. 11 to 14 are perspective views for explaining other embodiments of the present invention.

FIG. 11 is a diagram corresponding to FIG. 6 of the embodiment described above. In this example, the layers 11 and 2
The ceramic green sheets 31 and 32 are pressed together and then cut into circular or plate shapes by punching, for example.

Each cut disk-shaped ceramic body is sintered at a predetermined temperature. The sintered body 37 thus obtained is the 12th
As shown in the figure. Next, the entire sintered body 37 obtained in this way is electrolessly plated with a conductive material such as nickel or copper, and then heat treated at about 300° C. to identify the plating layer. Ru. A plurality of sintered bodies 37, the entirety of which has been electrolessly plated in this manner, are bundled, stacked one on top of the other as shown in FIG. 13, and hardened with wax. The plating layer on the S side of the plurality of sintered bodies 37 hardened with wax is easily removed by, for example, centerless polishing. The plurality of sintered bodies 37 from which the plating layer has been removed are separated again. The ceramic capacitor 39 thus obtained is shown in FIG. The other steps in this embodiment are the same as those in the embodiment described above with reference to FIGS. 3 to 8, so their explanation will be omitted. This embodiment is characterized by the overlapping first ceramic green sheets 1
By cutting the ceramic green sheets 12 of 1 and 12 into a disk shape, a ceramic capacitor 39 having an overall disk shape is formed, and the plating (1) formed by electroless plating is removed by centerless polishing. The goal is to do things more efficiently. Since the other steps are the same as those in the embodiment described above, it is possible to manufacture a small-sized, large-capacity ceramic capacitor at low cost and with high efficiency as in the embodiment described above.

In each of the above embodiments, the electrode patterns and the through holes are formed in three rows in the first and second ceramic green sheets, but the present invention is not limited to this. That is, any number of through-holes and electrode patterns may be formed in order to mass-produce on a desired scale.

Furthermore, although each of the above embodiments describes a method for manufacturing multiple ceramic capacitors at the same time, the teaching method according to the present invention may also be used to manufacture ceramic capacitors one at a time. . That is, it is not necessarily necessary to use a rolled ceramic green sheet like the ceramic green sheets shown in FIGS. 3 and 1li4. Furthermore, the number of through holes formed in the second ceramic green sheet does not need to match the number of electrode patterns formed in one of the first ceramic green sheets. A plurality of through holes may be formed per electrode pattern. In addition, when the ceramic capacitor obtained in each of the above-mentioned Examples is put to practical use, it may be used as a chip material as it is, or a lead wire may be attached thereto.

As described above, according to the present invention, one electrode and the lead-out electrode for configuring the capacitor are formed by electroless plating, so it is possible to mass-produce small-sized and human-harmful ceramic capacitors extremely efficiently. becomes. Also,
Since an inexpensive material such as nickel or copper can be used as the conductive material used in electroless plating, it is possible to manufacture the capacitor at a much lower cost than conventional ceramic capacitors.

[Brief explanation of the drawing]

FIG. 1 is a plan view illustrating a ceramic capacitor as a prior art example of the present invention. Figure 12 shows the first,
It is a sectional view along line II-II of the figure. Figure 3 shows the first
FIG. 3 is a perspective view for explaining a process of forming one electrode pattern for a capacitor on one side of a ceramic green sheet. FIG. 4 is a perspective view for explaining the process of forming electrode extraction holes in the second ceramic green sheet. FIG. 5 is a perspective view for explaining the process of overlapping the first ceramic green sheet and the second ceramic green sheet. FIG. 6 is a perspective view showing the step of cutting the first and second ceramic green sheets that are overlapped and integrated into one piece. FIG. 7 is a perspective view showing a cage body obtained by drying the cut ceramic body. FIG. 8 shows a perspective view of a ceramic capacitor obtained by the embodiment shown in FIGS. 3 to 7. FIG. FIG. 9 is a plan view showing in more detail the ceramic capacitor obtained by the embodiment described with reference to FIGS. 3 to 8. FIG. FIG. 10 is a cutaway view taken along line xx in FIG. 9. FIG. 11 is a perspective view for explaining another embodiment of the present invention, and corresponds to the right end portion of FIG. 6. FIG. 12 is a perspective view showing a sintered body obtained according to another embodiment of the present invention. 13th
The figure is a perspective view showing a plurality of sintered bodies solidified with wax. FIG. 14 is a perspective view (not shown) of a ceramic capacitor obtained according to another embodiment of the present invention. In the figure, 11 is a first ceramic green sheet;
12 is the second ceramic green sheet, 13 is one electrode pattern for the capacitor, 14 is the electrode extraction hole, 17 is the sintered body, 18°, 19.20.21 is the side surface of the sintered body, and 22 is the side surface of the sintered body. Ceramic capacitor, 23 is one electrode for the capacitor, 24 is the other electrode for the capacitor, 31 is w41 ceramic green sheet 1-
132 is a second ceramic green sheet, 37 is a sintered body, and 39 is a ceramic capacitor. Island 1f17 ffi”sII Akira Z Man 4th Old

Claims (1)

[Claims] A step of forming one electrode pattern for a capacitor on one side of a first ceramic green sheet, and preparing a second ceramic green sheet or a ceramic green molded body in which a through hole for taking out the electrode is formed. A step of placing the 11112 ceramic green sheet or ceramic green molded body on the surface of the first ceramic green sheet on which the electrode pattern is formed so that the through hole is located above the electrode pattern. a step of sintering the first ceramic green sheet and the second ceramic green sheet or the ceramic green molded body that have been stacked together to form a sintered body; plating, and removing the plated portion of the IIWJ of said sintered body plated throughout to form a pair of electrodes, thereby forming a take-out electrode in contact with one electrode for said capacitor. ,
A method for manufacturing a ceramic capacitor, which includes a step of forming a second electrode for the capacitor.