JPH0362293B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a single-plate capacitor in which capacitance electrodes are formed on two main surfaces facing each other.

Prior Art The above-mentioned single-plate capacitor is manufactured by the process shown in FIG. That is, as shown in Figure A, a business card-sized motherboard 1 is made by sheet molding, and its two opposing main surfaces 2a and 2b are provided with break grooves 3a for chip breaking as shown in Figure B.
3b... are formed in a grid shape. Then set this to 1200
After firing at a temperature of ~1400 DEG C., a capacitor electrode 4 made of silver-palladium alloy or the like is applied to the two main surfaces 2a, 2b across the grooves 3b as shown in FIG. Next, the motherboard 1 is broken along the grooves 3a (hereinafter, this break is referred to as a lateral break), and the connection electrodes are placed in contact with the end sides of the capacitor electrodes 4, 4, as shown in FIG. 5. Apply... The connection electrode 5 is also made of silver, the same as the capacitance electrodes 4, 4.
A palladium alloy or the like is used. With the electrodes 4 and 5 applied in this way, the electrodes are baked at a temperature of approximately 800°C.Then, the surface of the connection electrode is coated with paraffin or the like that repels the exterior paint, chip-broken, and the connection electrode is sealed. The single-plate capacitor shown in Figure E is obtained through a step of coating the entire circumferential surface with exterior paint (not shown).

Problems to be Solved by the Invention By the way, according to the above manufacturing method, since the capacitor electrodes are applied before chip breaking the motherboard, the capacitor electrodes 4, 4 are also applied to the break grooves 3b...
will enter and be burned into the groove wall (see Figure 4A). Therefore, in the single-plate capacitor obtained by chip breaking, the capacitance electrode portions burned into the groove wall surface face each other at the top and bottom, as shown in Figure 4B, and the distance between them is l.
There is a problem in that the withstand voltage of the capacitor is significantly lowered due to In this case, the above problem could be solved if there was a coating method that would prevent the electrode from entering the break groove, but there is no such coating method, and therefore, in order to prevent the capacitor's withstand voltage from decreasing, the thickness of the dielectric must be adjusted. must be made thicker,
The drawback was that it was not suitable for small size and high capacity.

The present invention attempts to solve this problem by using a clever method to prevent the electrode from entering the breaking groove.

Means for Solving the Problems The present invention provides a motherboard in which breaking grooves for chip breaking are formed in a lattice shape on two opposing main surfaces, and then capacitance electrodes are applied and baked on both main surfaces. In the method for manufacturing a single-plate capacitor that is then chip-broken, the capacitance electrodes are removed after baking, before the capacitance electrodes are applied to the break grooves carved on the two main surfaces of the motherboard. It is characterized by being filled with a filler that can be used.

Function: If the break groove is filled with a filler that can be removed after the electrode is baked before applying the capacitor electrode, the presence of this filler will prevent the break groove from forming after the capacitor electrode is baked. It is possible to effectively prevent the capacitor electrode from sticking to the wall surface. Therefore, the facing distance between the capacitor electrodes becomes equal to the distance between the two main surfaces of the chip unit, making it possible to obtain a compact, high-voltage, high-capacity capacitor.

Embodiment FIG. 1 is a process diagram illustrating a method for manufacturing a single-plate capacitor according to the present invention, and the manufacturing procedure will be explained based on this diagram. First, a motherboard is obtained by sheet molding (step A), and break grooves are formed on its two main surfaces (step B). The motherboard at this time is shown in FIG. 2A, and its structure is exactly the same as that shown in FIG. 3B. Grooves 3a, 3b
The depth of is 0.3 if the thickness of motherboard 1 is 1mm.
It is about mm. However, the vertical grooves 3b are somewhat shallower than the horizontal grooves 3a. This happens when there is a horizontal break.
This is to prevent cracking along the vertical grooves 3b.
Note that dielectric ceramics such as barium titanate are used as the raw material for the motherboard 1.

Next, the dielectric made of this motherboard is fired.

Next, the two main surfaces 2 of the motherboard 1
The break grooves 3a and 3b formed in the grooves a and 2b are filled with a filler (step c). For the filler, choose a material that burns out at the electrode baking temperature (approximately 800℃). An example of such a material is carbon. To fill the break grooves 3a, 3b, . . . with filler, carbon is applied to the main surface of the motherboard using a brush or the like. By this application, the motherboard main surface 2
Carbon may also adhere on a and 2b, but
Its thickness is very thin, and it burns off during electrode baking, so it does not interfere with electrode baking. FIG. 2B shows a state in which the break grooves 3b are filled with carbon. 6 is carbon. carbon 6
Once filling is completed, capacitor electrodes are applied to the main surface of the motherboard (Step 2). The state in which the capacitor electrode is applied is shown in Figure 2C. As the capacitor electrode 4, a silver-palladium alloy or the like is used as in the conventional case. After coating the capacitor electrode 4, a break is made along the horizontal groove 3a (step E), a connection electrode is coated (step H), and the electrode is baked (step T). In this baking step, since the grooves 3b are filled with carbon 6, the capacitor electrode 4 does not enter into the grooves 3b. On the other hand, the carbon 6 does not remain in the grooves 3b forever, but burns off and disappears from the grooves 3b by the time baking is completed. Therefore, when the baking is completed, the capacitor electrode 4 is baked only onto the main surfaces 2a and 2b, as shown in FIG. 2D.

Thereafter, as in the past, the surface of the connection electrode is coated with paraffin that repels the exterior paint (process 1), chip-broken (process 3), and exterior paint is applied to obtain a single-plate capacitor (process 2). In the thus manufactured single-plate capacitor, as shown in FIG. becomes long as l′ (>l),
No drop in pressure resistance occurs.

In the above embodiment, carbon is used as a filler and is burnt off when baking the capacitor electrode, but the present invention is not limited to this. Alternatively, an inorganic substance that does not react with firing may be used as a filler, and the unsintered inorganic substance may be removed from the groove after the capacitor electrode is baked. As a result, the capacitor electrode provided on the inorganic material is removed, and each capacitor electrode is formed separately. In this example, when the inorganic material is applied to the surface of the motherboard, care must be taken to only fill the grooves, since the capacitive electrodes will be removed later.

Effects of the Invention As explained above, according to the method for manufacturing a single-plate capacitor according to the present invention, the capacitor electrode is applied to the main surface of the motherboard while the break groove is filled with a filler that can be removed after the electrode is baked. ,after that,
Since the electrode is baked, it is possible to effectively prevent the capacitor electrode from being attached to the wall of the break groove.
Therefore, it is possible to obtain a single-plate capacitor in which the facing distance between the capacitor electrodes is kept equal to the distance between the two main surfaces, resulting in a small size and high capacity capacitor.

[Brief explanation of drawings]

FIG. 1 is a process diagram explaining the manufacturing method of the present invention,
FIG. 2 is a diagram showing the machining state of the motherboard in the main steps shown in FIG. 1, FIG. 3 is a diagram showing a conventional method of manufacturing a single-plate capacitor, and FIG. 4 is a diagram illustrating the drawbacks of the conventional method. 1...Motherboard, 2a, 2b...Main surface, 3
b, 3b...Break groove, 4...Capacitor electrode, 5...
Filling material.

Claims (1)

[Scope of Claims] 1. After firing a motherboard in which break grooves for chip breaking are formed in a lattice shape on two opposing main surfaces, capacitance electrodes are applied and baked on both main surfaces, and then chip breaking is performed. In the method for manufacturing a single-plate capacitor, a filler that can be removed after baking of the capacitor electrodes is added to the break grooves carved on the two main surfaces of the motherboard before applying the capacitor electrodes. A method for manufacturing a single-plate capacitor characterized by filling.