JPS5827315A - 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 manufacturing a ceramic capacitor, particularly,
This invention relates to a method of manufacturing a ceramic capacitor with a small capacity.

Generally, electronic components are required to be small, but there are cases where miniaturization is intentionally avoided. For example, a small-capacity capacitor is relatively small, but in order to make it the same size as other electronic components, it is sometimes intentionally made large. This is because handling such as shipping the product and mounting it on an electronic circuit becomes easier. by the way,
The capacitance of a capacitor is determined by the overlapping area of a pair of opposing electrodes, the electrical distance, and the dielectric constant of the dielectric layer. Therefore, in order to reduce the capacitance of a capacitor, from the viewpoint of the shape of the capacitor, it is required to reduce the overlapping area of the electrodes and to increase the distance between the electrodes. In particular, in order to achieve a minute capacitance such as 1 ELF, the overlapping area must be extremely small and the distance between the electrodes must be extremely large. Conventionally, this 1! To meet the requirements, capacitors of various structures have been proposed and implemented.

FIGS. 1 to 4 are diagrams showing three examples of structures of microcapacitance capacitors that have been proposed in the past.

FIG. 1 is a perspective view showing a first example of a conventional microcapacitor, and FIG. 2 is a front view of the microcapacitor shown in FIG. 1, although the scale is different. Figures 1 and 2
As is clear from the figure, in this capacitor 1, two electrodes 1i3.4 are formed on the upper surface of the dielectric layer 2.

This ceramic capacitor 1 is a so-called edge capacitance type capacitor. That is, the two electrodes 3.4 constituting the capacitor are not faced to each other but are formed on the same plane. Therefore, it is equivalent to an extremely large distance between the electrodes, so
This is a capacitor with a very small capacity.

FIG. 3 is a front view showing a second example of a conventional microcapacitance capacitor, and corresponds to FIG. 2 of the first example described above. As is clear from FIG. 3, the microcapacitor 1 of this second example has three electrodes 3.4.5. The electrode 3 and the electrode 4 are formed on the upper surface of the dielectric layer 2 and exist on the same plane, similarly to the microcapacitance capacitor 1 of the first example. On the other hand, the electrode 5 is connected to the dielectric layer 2
It is formed on the other side of , that is, the lower surface in FIG. 3, and partially faces electrodes 3 and 4 with dielectric layer 2 interposed therebetween. In the second example of the microcapacitance capacitor 1 shown in FIG. 3, capacitance is taken out by the electrodes 3 and 4. This means that the 1s1 capacitor composed of electrodes 3 and 5 and the second capacitor composed of electrodes 5 and 4 are equivalent to being connected in series. . That is, in the microcapacitance capacitor 1 of the second example shown in FIG.
A small capacitance is achieved by a structure in which two capacitors each consisting of electrodes are substantially connected in series.

FIG. 4 is a perspective view showing a third example of a conventional microcapacitance capacitor. In the third example of the microcapacitance capacitor 1, a lead wire 6.7 is inserted inside the dielectric layer 2. Here, the lead wires 6 and 7 inside the dielectric layer 2 are
The capacitance is taken out by the end face of.

As mentioned above, various types of microcapacitance capacitors have been proposed.
All of the microcapacitance capacitors in the example above had the disadvantage that they were extremely difficult to manufacture. In particular, in order to accurately obtain a minute capacitance, it is necessary to accurately determine the positional relationship between a pair of opposing electrodes, making it extremely difficult to automate the manufacturing process. In addition, in the third example shown in FIG. 4, the lead wire is inserted before sintering, so the lead wire is approximately 1
It is necessary to withstand 400 steps of sintering, so it is necessary to use a material with a high melting point. Examples of such high melting point materials include platinum and palladium, but they are extremely expensive and have the disadvantage of increasing the price of ceramic capacitors.

Therefore, the main object of the present invention is to provide a method by which a small capacitance ceramic capacitor can be easily manufactured at a lower cost.

Another object of the present invention is to provide a method for manufacturing a ceramic capacitor of the same size as a large capacitance capacitor, even if it has a minute capacitance.

To summarize, the present invention includes a step of forming a conductive film on the inner surface of each of the through holes of a ceramic body in which two through holes are formed; a lead wire insertion step of inserting the lead wire, a soldering step of immersing the ceramic body into which the lead wire has been inserted into a solder bath, and a step of dividing the lead wire to form two lead wires drawn out from the electrode for the capacitor. This is a method of manufacturing a ceramic capacitor including a lead wire forming step.

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.

Figures 5 to 10 are diagrams for explaining the first real part of the present invention, and the following explanation will show Figures 5 to 10 and each process of this embodiment. This is done with reference to FIG. In addition, for ease of explanation,
It is noted that the drawings are drawn to scale.

Referring to FIG. 20, this embodiment first begins with a ceramic body preparation step 31. A ceramic body 10 as shown in FIG. 5 is prepared. Ceramic body 10
Two through holes 11 and 12 are formed in the. The inner diameter of each through hole 11.12 is chosen to be larger than the outer diameter of the lead wire described below.

Next, a conductive film forming step 32 shown in FIG. 20 is performed. For example, silver-palladium is applied to the inner peripheral surface of each straight hole 11.12 and then baked.

The conductive film is a portion from which the capacitance of the ceramic capacitor manufactured according to this embodiment is taken out. In addition,
Materials for forming conductive films are not limited to silver palladium.
Various conductive materials can be used, and various film forming methods can be used, such as not only coating but also electroless plating after resist formation or grinding the top and bottom surfaces of the ceramic body 1o after electroless plating. obtain.

Next, a lead wire preparation step 33 shown in FIG. 20 is performed.

A U-shaped lead [13] as shown in FIG. 6, which will be described later, is prepared. Note that the lead wire 13 is not necessarily limited to the overall U-shape as shown in FIG. 6, but may be entirely V-shaped. Furthermore, in this embodiment, since the ceramic body 10 has already been sintered, it is not necessary to use a material with a high melting point, such as platinum wire, for the lead wire 13. That is, it is possible to use inexpensive materials such as copper.

Referring to FIG. 20, a lead wire insertion step 34 is performed. The overall U-shaped lead wire 13 is inserted into each through hole 11.12 of the ceramic body 1o from its both ends. In this way, the ceramic body 1o into which the lead wire 13 is inserted
6th rj! It is shown in a partially cut away perspective view at J.

Next, the solder dipping step 35 in FIG. 20 is performed. The state during the solder dipping step 35 is shown in a side sectional view in FIG. A solder dipping bath 14 is prepared. Molten solder 15 is prepared inside the solder dipping tank 14. The ceramic body 1o with the leads i*i3 inserted into the molten solder 15 is the seventh ceramic body 1o.
It is immersed in the direction of arrow X in the figure.

Next, a solder solidification step 36 in FIG. 20 is performed. The ceramic body 1o immersed in molten solder 15 as shown in FIG. At this time, the through hole 11 of the ceramic body 10.
Since the molten solder 15 enters the inside of the lead wire 12 in the same way as the through hole of the printed circuit board, it is cooled at room temperature and connects the lead wire 13 and the through hole 1 of the ceramic body 1o.
1.12 is soldered to the conductive film on the inner peripheral surface.

The ceramic body 10 to which the lead wires 13 are soldered in this manner is shown in cross-section in FIG. That is, a solder layer 16.17 is present inside each through hole 11.12 of the ceramic body 1o, and the ceramic body 10
and the lead wire 13 are fixed.

Next, a lead wire cutting step 37 shown in FIG. 20 is performed.

The lead wire 13 soldered to the ceramic body 10 is
It is cut in the direction of the alternate long and short dash line Y in FIG. The bent portion of the overall U-shaped lead wire 13 is cut and removed. A front view of the ceramic body 1o with part of the lead wire 13 cut off in this way is shown in FIG. The remaining portion of the lead wire 13 separated at the bent portion is divided into two portions 13A.
and 13B. As is clear from Figure 9,
The remaining lead wire portions 13A and 13B constitute two lead wires drawn out from the electrodes for the capacitor.

Next, the dipping step 38 in FIG. 20 is performed.

Ceramic body 10 shown in FIG. and lead wire 1
The remaining portions 13A and 13B of No. 3 are subjected to dipping. This dipping is performed to protect the capacitor chip. FIG. 10 is a sectional view showing the state of bales that have been dipped. In this way, a ceramic capacitor of minute capacity is manufactured.

In this embodiment described above, each step can be performed entirely manually. Therefore, a capacitor with a small capacitance can be easily manufactured. Further, since the lead wire 13 is inserted after firing the ceramic body 10, there is no need to use an expensive high melting point material for the lead wire 13, and the lead wire 13 can be manufactured at low cost.

Figures 11 to 13 are diagrams for explaining the second embodiment of the present invention. The feature of the second embodiment is that the lead wire insertion step 34 in FIG. 20 described in the previous embodiment is performed. That is, each step up to the lead wire preparation step 33 in FIG. 20 is the same as in the previous embodiment described with reference to FIGS. 5 to 10. Further, each step after the solder dipping step 35 shown in FIG. 20 is also the same as in the previous embodiment.

Therefore, only the steps different from the previous embodiment will be explained. FIG. 21 is a diagram showing the steps that characterize this second embodiment. The lead wire insertion step 34 consists of two steps. First, the lead wire insertion step 34A in FIG. 21 is performed. That is, the entire U-shaped lead [113 is
It is inserted into the through hole 11.12 of the ceramic body 10. This is similar to the situation shown in FIG.

Next, the lead wire bending step 34B of FIG. 21 is performed. The inserted lead wire 13 is bent parallel to the ceramic body 10 on the side opposite to the bent portion, that is, on the sides of both ends. The state of this bent lead wire 13 is
FIG. 1 shows a front view, and FIG. 12 shows a side view. That is, the bent portion of the lead wire 13 is parallel to the ceramic body 10 and is in contact with one side of the ceramic body 10 . This solder dipping step 35 and subsequent steps are carried out, and the lead wire 13 is cut in the direction shown by the dashed line Z in FIGS. 11 and 12. This corresponds to FIG. 8 in the embodiment described above, and is not particularly different. FIG. 13 is a perspective view showing the ceramic capacitor 1 obtained by this second example.

FIGS. 14 and 15 are perspective views for explaining a third embodiment of the invention. The features of the third embodiment are as follows:
The difference is that the lead wire preparation step 33 and the lead wire insertion step 34 in the previous embodiment described with reference to FIG. 20 are different. Since the other processes are the same,
No particular explanation will be provided. Referring to FIG. 14, the lead wire 13 used in the third embodiment is similar to the previous embodiments in that it has a U-shape overall, but has folds bent at right angles at both ends. The difference is that it includes music portions 13G and 13D. That is, in this third embodiment, a lead wire 13 as shown in FIG. 14 is prepared. Next, a lead wire insertion step 34 is carried out, and the lead wire 13 is inserted into the ceramic body 10 by inserting the lead wire 13 into the ceramic body 10.
This is implemented by folding portions 13C and 130 of 3. The bent portion 13C is inserted into the through hole 11 of the ceramic body 10, and the other bent portion 13D is inserted into the true through hole 12. The ceramic body 10 into which the lead wire 13 has been inserted in this manner is shown in FIG.

As is clear from FIG. 15, in this third embodiment,
Lead wires 13 are positioned to sandwich ceramic body 10 . The following steps are similar to those in the previous example described with reference to FIG. 20, but the ceramic capacitor obtained in this third example is different from the ceramic capacitor obtained in the second example. Similar to the capacitor, lead wire 13
The remaining portions of the holes form a right angle to each through hole 11.12.

FIG. 16 is a perspective view for explaining a fourth embodiment of the invention. The feature of the fourth embodiment is that the conductive film forming step 32 in FIG. 20 explained for the first embodiment is different. Since the other steps are the same, their explanation will be omitted.

In the fourth embodiment, the conductive film is formed not only on the inner peripheral surface of each through hole 11 , 12 of the ceramic body 10 but also on the surface of the ceramic body 10 . That is,
A conductive material, for example silver palladium, is applied to each straight hole 1.
1.12 and a part of the surface of the ceramic body 10, that is, around the opening of each through hole 11.12.

A perspective view of the ceramic body 10 on which a conductive film is formed in this manner is shown in FIG. 16. After the conductor film is formed around the opening of each through hole 11.12, the solder is dipped into the solder so that the solder adheres not only to the inside of each through hole 11.12 but also around the opening. Therefore, the lead wire 13 is more firmly fixed to each through hole 11.12.

FIG. 17 and FIG. 18 are diagrams for explaining a fifth embodiment of the present invention. The feature of the fifth embodiment is that the second
It is in the lead wire preparation step 33 of zero cause. A lead wire 13 having a U-shaped bent portion as shown in a front view in FIG. 17 is prepared as a lead wire having an overall U-shape. That is, the lead 1113 has bent portions 13E and 13F that are bent inward to form the entire 0-shape. This bent part 13
E13F is selected to have a shape such that when the lead wire 13 is inserted into each through hole 11.12 of the ceramic body 10, it comes into contact with the surface of the ceramic body 10. Figure 18 shows
The lead wire 13 in the fifth embodiment is connected to the ceramic body 10.
FIG. In the fifth embodiment, solder is also attached to the bent portions 13E and 13F of the lead wire 13, and seven flange bodies made of solder are formed around the opening of each through hole 11.12. Because of this shape, it is possible to increase the adhesion strength between the lead wire 13 and each through hole 11.12. Note that in this fifth embodiment, like the fourth embodiment, each through hole 11.
A conductive film may be formed around the openings 12, thereby making it possible to further strengthen the adhesion between the lead wire 13 and each through hole 11.12. Regarding other points, see Section 20.
It has the same effect as the previous embodiment described with reference to the figures.

In each of the embodiments described above, all the ceramic bodies 10 are illustrated as having a rectangular plate shape, but the ceramic bodies 10 used in the present invention are not limited to the rectangular plate shape. That is, a disc-shaped ceramic body 10 as shown in FIG. 19 may be used. Furthermore, ceramic bodies of various shapes can be used, not limited to the rectangular plate shape or disc shape. Furthermore, the overall shape of the lead wire used in this invention is not limited to the U-shape;
Needless to say, it may be a letter shape.

As described above, according to the present invention, a microcapacitance ceramic capacitor can be easily manufactured without using manual labor. In addition, it becomes possible to obtain a ceramic capacitor of minute capacity that can be produced efficiently and at low cost. Further, since the capacitance of the capacitor is determined by the size and shape of the through hole that can be accurately machined, it is possible to manufacture a microcapacitance capacitor with an accurate capacitance. Furthermore, it becomes possible to obtain a microcapacitance capacitor with a novel structure that has not been seen before.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first example of a conventional microcapacitance capacitor. FIG. 2 is an enlarged front view of the microcapacitance capacitor shown in FIG. 1. FIG. 3 is a front view showing a second example of the conventional micro volume 11212. FIG. 4 is a perspective view showing a third example of a conventional microcapacitance capacitor. FIG. 5 is a perspective view showing a ceramic body prepared in a first embodiment of the invention. FIG. 6 is a partially cutaway perspective view showing the ceramic body into which a lead wire is inserted. 7th
The figure is a cross-sectional view showing a ceramic body into which lead wires are inserted during a solder dipping process. FIG. 8 is a sectional view showing a ceramic body to which lead wires are soldered. FIG. 9 is a front view showing the ceramic body with some of the lead wires cut off. FIG. 10 shows a cross-sectional view of a ceramic capacitor manufactured according to a first embodiment of the invention. FIG. 11 is a front view showing a state in which a lead wire used in a second embodiment of the present invention is inserted into a ceramic body. FIG. 12 is a side view of the state shown in FIG. 11. FIG. 13 is a perspective view showing a ceramic capacitor obtained according to a second embodiment of the present invention. FIG. 14 is a perspective view showing a linear transport used in a third embodiment of the present invention. FIG. 15 is a perspective view showing the ceramic body into which the lead wire shown in FIG. 14 is inserted. FIG. 116 is a perspective view showing the ceramic body used in the fourth embodiment of the present invention, showing a state in which a conductive film is formed. FIG. 17 is a perspective view showing the ceramic body used in the fifth embodiment of the present invention. It is a front view showing a lead wire. FIG. 18 is a front view showing the lead wire shown in FIG. 17 inserted into the ceramic body. FIG. 11119 is a perspective view showing an example of another shape of the ceramic body used in the present invention. The IF520 diagram is a diagram illustrating each combination of the first embodiment. FIG. 21 is a diagram showing the steps that characterize the second embodiment. In the figure, 1 is a ceramic capacitor, 10 is a ceramic body, 11.12 is a through hole, 13 is an entire U-shaped lead wire, 13A and 13B are parts corresponding to two lead wires drawn out from electrodes for the capacitor, 15 is soldering, 31 is a preparation process, 32 is a conductive film forming process, 34 is a lead wire insertion process, 35 is a solder dipping process, 36 is a solder solidification process, and 37 is a lead wire cutting process. Figure 5 - Figure 6 O I 11th Figure 12 Figure 1j circle Figure 74 Figure 75 circle 7 Figure 770 1st circle 1st circle

Claims (1)

[Claims] A conductive film forming step of preparing a ceramic body in which two through holes are formed, and forming a conductive film serving as an electrode constituting a capacitor on the inner surface of each of the through holes. A lead wire insertion step of preparing a V-shaped lead wire and inserting the lead wire into two through holes of the ceramic body from both ends of the lead wire, and melting the ceramic body into which the lead wire has been inserted. a soldering step of soldering the lead wire and the through hole by immersing it in solder; and cutting the bent portion of the lead wire, thereby forming two lead wires that are drawn out from the electrodes for the capacitor. A method for manufacturing ceramic capacitors that includes a lead wire forming process.