JP2559471B2 - Chip resistor manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a chip resistor, and more particularly to a method for manufacturing a chip resistor in which a side surface electrode is formed on an inner wall surface of a through hole of a ceramic substrate.

[Conventional technology]

As shown in FIG. 3, a chip resistor of this type is formed on the ceramic substrate 1, which is divided and formed, the surface electrode 2 and the resistor 3 formed on the surface of the ceramic substrate 1, and the rear surface of the ceramic substrate 1. Although not shown in the figure, the surface of the resistor 3 is overcoated with a glass material, although it is mainly composed of a back surface electrode 4 and a side surface electrode 5 continuous with the front and back electrodes 2 and 4. The surfaces of the electrodes 2, 4, 5 are plated with nickel and solder.

Conventionally, the chip resistor A is generally manufactured as follows.

First, prepare a green sheet in which a slurry formed by mixing ceramic powder, binder resin, etc. is formed into a thin plate,
As shown in FIG. 4, a large number of through holes 6 and vertical and horizontal dividing grooves 7 and 8 are formed in this green sheet by pressing and then baked to obtain a hard ceramic substrate 1. here,
The dividing grooves 7 and 8 are arranged at a predetermined interval as shown in the figure, and are grooves for later separating into individual chip resistors. It overlaps. Next, silver paste is screen-printed around the through holes 6 on the surface of the ceramic substrate 1,
As shown in FIG. 5, by sucking the silver paste B from the back surface side of the ceramic substrate 1 through the through holes 6, the surface electrode 2 patterned on the surface of the ceramic substrate 1 and the through surface electrode 2 are passed through. The side surface electrode 5 extending into the hole 6 is formed. Similarly, the back surface electrode 4 is screen-printed on the back surface of the ceramic substrate 1, and the side surface electrode 5 extending from the back surface electrode 4 into the through hole 6 is formed.
Print by suction. As a result, the side surface electrode 5 covers the inner wall surface of the through hole 6 and is continuous with the front and back electrodes 2 and 4. Then, a resistor 3 is formed by printing between the pair of surface electrodes 2, 2.
After a part of the adhered surface is removed by a known method such as laser trimming to adjust the resistance value, the surface of the resistor 3 is overcoated with a glass material. Thereafter, the ceramic substrate 1 is divided along the dividing grooves 7 and 8, and nickel plating and solder plating are applied to the surfaces of the electrodes 2, 4 and 5 to obtain a large number of individual chip resistances A as shown in FIG.

[Problems to be Solved by the Invention]

By the way, in the above-mentioned conventional technique, as a method of forming the side electrode 5 of the chip resistance, the suction printing of sucking the silver paste through the through hole 6 is performed. It is not easy to form a silver paste having a uniform film thickness on the inner wall surface of the above, and especially if the film thickness becomes undesirably thin, there is a risk that silver blemishes may occur and conduction failure may occur. When such a defective product is generated and put on the market, it may cause serious problems such as recovering all the chip resistances of the same type, while paying close attention to the film thickness of the side electrode during manufacturing. Mass production will be impaired if it tries.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for manufacturing a chip resistor in which a side electrode having a uniform film thickness can be reliably formed and mass productivity is good.

[Means for solving the problem]

In order to achieve the above-mentioned object, the present invention divides a ceramic substrate along a dividing groove including through holes, and then applies a plurality of wires coated with a conductive paste by tensioning these through holes at equal pitches. The conductive paste was transferred by pressing against the inner wall surface of each through hole, and the side electrode was formed by this transfer.

[Action]

That is, according to the present invention, since the conductive paste as the side surface electrode is directly transferred to the inner wall surface of the through hole exposed on the divided surface, the conductive paste is always formed to have a substantially uniform film thickness, and a plurality of conductive pastes are formed. Since the conductive paste can be collectively transferred and formed at a plurality of locations by using the wire, mass productivity is not impaired.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are for explaining one embodiment of the present invention. FIG. 1 is an explanatory view showing a silver paste transfer process at the time of forming a side electrode, and FIG. 2 is a ceramic after the silver paste transfer. It is a perspective view of a division plate, and the same code | symbol is attached | subjected to the part corresponding to FIGS.

In the manufacturing process of this embodiment, the method of forming the ceramic substrate having the through holes and the vertical and horizontal dividing grooves, the method of forming the front and back electrodes and the resistor, etc. are the same as those of the conventional technique described above, and therefore the description thereof is omitted. To do.

Now, the patterns of the front surface electrode 2, the back surface electrode and the resistor 3 are formed by printing on both front and back surfaces of the ceramic substrate, and the resistor 3
If an overcoat is applied to the ceramic substrate, the ceramic substrate is first divided along the dividing groove that overlaps the through hole 6, and a plurality of elongated ceramic dividing plates 1a in which the inner wall surface of each through hole 6 is exposed on the dividing surfaces 7a and 7b. Get the book. Then, as shown in FIG. 1, the ceramic dividing plate 1a is placed in a silver paste bath 10
A plurality of wires 11 which can be moved in the vertical direction in the drawing are stretched in the same pitch as the through hole 6 below the ceramic division plate 1a. Then, these wires 11 are first dipped in a silver paste bath 10 and then raised, and the inner wall surface of each through hole 6 exposed to one of the divided surfaces 7a of the ceramic division plate 1a is provided with silver on the outer peripheral surface. Each wire 11 coated with the paste is pressed. As a result, the silver paste is transferred and formed on the inner wall surface of the through hole 6 with a substantially uniform film thickness. In the same way, ceramic dividing plate
The silver paste is also transferred to the inner wall surface of each through hole 6 exposed to the division surface 7b on the other side of 1a to form side electrodes 5 continuous to the front and back electrodes on both side surfaces of the ceramic division plate 1a.

After that, the ceramic division plate 1a is subdivided (secondary division) along the division groove 8 and the surfaces of the front surface electrode 2, the back surface electrode and the side surface electrode 5 are plated with solder and soldered to obtain a large number of individual chip resistances. obtain.

As described above, in the above-described embodiment, as a method of forming the side surface electrode 5, instead of performing the suction printing in which the film thickness tends to vary, a plurality of wires 11 stretched in the same pitch as the through hole 6 is used. Since the method of directly transferring the silver paste is used, the side electrode 5 having a substantially uniform film thickness can be reliably formed, the reliability of the chip resistance is significantly improved, and the ceramic division plate 1a is Since the silver paste can be collectively transferred and formed on the inner wall surfaces of the plurality of through holes 6 that are exposed to the side surface of, the mass productivity is also good.
In addition, since a small amount of silver paste flows into the opening end of the through hole 6 when the front surface electrode 2 and the back surface electrode are printed,
There is no concern that the film thickness will become thin at the connecting portion between the front and back electrodes and the side surface electrode 5.

Regarding the chip resistance without the back electrode,
It goes without saying that the present invention is applicable.

〔The invention's effect〕

As described above, according to the present invention, the conductive paste as the side surface electrode is transferred and formed on the inner wall surface of each through hole exposed to the dividing surface by using a plurality of wires stretched in the same pitch as the through hole. Unlike conventional suction printing, which tends to cause variations in film thickness, it is possible to reliably form side electrodes with an almost uniform film thickness, avoid the occurrence of defective products, and collect them in multiple locations. Since the conductive paste can be transferred and formed, there is no fear of impairing mass productivity.

[Brief description of drawings]

1 and 2 are for explaining one embodiment of the present invention. FIG. 1 is an explanatory view showing a silver paste transfer process at the time of forming a side electrode, and FIG. 2 is a ceramic after the silver paste transfer. FIG. 3 is a perspective view of the division plate, FIG. 3 is a perspective view of the chip resistor, and FIG.
FIG. 5 and FIG. 5 are for explaining the prior art, FIG. 4 is a plan view of the ceramic substrate before division, and FIG. 5 is an explanatory view showing a suction printing process at the time of forming the side electrodes. 1 ... Ceramic substrate, 1a ... Ceramic dividing plate, 2 ...
… Surface electrode, 3 …… resistor, 5 …… side electrode, 6 …… through hole, 7,8 …… dividing groove, 7a, 7b …… dividing surface, 10 ……
Silver paste bath, 11 ... wire.

Claims (1)

(57) [Claims] 1. A pattern of electrodes and resistors is formed by printing on the surface of a ceramic substrate having a large number of through holes formed therein, and the ceramic substrate is divided along division grooves to expose the through holes on the divided surfaces. In a manufacturing method in which a large number of chip resistors having side electrodes on the inner wall surface of the through hole are provided, the ceramic substrate is divided along the dividing groove including the through hole, and then these through holes are formed. A chip resistor characterized in that a plurality of wires stretched around a pitch and coated with a conductive paste are pressed against the inner wall surface of each through hole to transfer the conductive paste, and the side electrodes are formed by this transfer. Manufacturing method.