JPH1116761A - Forming method of outer electrode of electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form fine outer electrodes arranged at a narrow pitch by a method, wherein a copper wire is wound on the surface of a part so as to overlap with the edge of an inner circuit and fixed, the disused part of the wound copper wire is removed, and the rest of the copper wire is made to serve as an outer electrode. SOLUTION: Four coils are built in a component main body 1 separating from each other by a certain space in a longer direction, the ends 2 of each coil are led out to the crosswise opposed sides of the component main body 1 respectively. Adhesive agent is applied in stripes so as to overlap with the led ends 2 of the coils. A lead wire 4, circular in cross section, is wound on the parts of the surface of the part main body 1 where the adhesive agent 3 is applied. The parts of the main body 1, where the lead wire 4 is wound are heated to cure the adhesive agent 3 to fix the lead wire 4 to the main body 1. Then, the wound lead wire 4 is removed from the center parts CA of the upper and lower surface of the component main body 1 by the use of a dicing device, a laser scribing device or the like, and the rest of the wound lead wire 4 is left on the two crosswise opposite sides and the hems of the upper and lower surface adjacent to the sides to serve as outer electrodes 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming external electrodes useful for various electronic parts such as chip parts and composite parts.

[0002]

2. Description of the Related Art A composite component called a chip component, an array, or a network (hereinafter collectively referred to as an electronic component) has external electrodes for making electrical connection to a connection partner such as a substrate electrode. Are provided on the surface of the component.

The shape and position of the external electrode vary depending on the component. For example, a rectangular parallelepiped chip component has a pair of four side surfaces (indicating surfaces other than the upper and lower surfaces) so as to cover the entire two opposing side surfaces. External electrodes are provided, and in the rectangular parallelepiped composite component, a plurality of external electrodes are provided so as to partially cover two opposing side surfaces of the four side surfaces.

FIG. 4 shows an inductor array having external electrodes corresponding to the latter.
Four 2-turn coils 102 are arranged side by side at intervals in the longitudinal direction, and the edge of each coil 102 is led out to each of two side surfaces in the width direction of the component body 101. Also, four strip-shaped external electrodes 103 are formed on each of the side surfaces at intervals in the longitudinal direction, and the leading ends of the coils 102 are connected to the external electrodes 103 facing each other in the width direction.

The above-mentioned external electrodes are generally formed by a method of applying an electrode paste containing a metal powder to a predetermined position of a component body in a predetermined shape, and baking and curing the paste. Method and the like are appropriately used.

[0006]

In the above-described conventional method of forming an external electrode, in which an electrode paste is directly applied to a component body and cured, there is a limit in reducing the paste application size and the pitch between applications. It is difficult to form external electrodes at a narrow pitch.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for forming an external electrode of an electronic component which can form fine external electrodes at a narrow pitch.

[0008]

According to the present invention, an external electrode is provided on the surface of a component so as to conduct with an end of an internal circuit led out to the surface of the component. In the method for forming an external electrode of an electronic component to be formed,
It is characterized in that a conductor is wound around the surface of the component so as to overlap with the end of the internal circuit and fixed, and then the unnecessary part of the wound conductor is removed and the remaining part is used as an external electrode.

According to a third aspect of the present invention, there is provided a method for forming an external electrode on an electronic component, wherein the external electrode is formed on the surface of the component so as to be electrically connected to an end of an internal circuit led to the surface of the component. A conductor film for an external electrode is formed, the component body is pressed relatively to the transfer sheet so that the internal circuit end overlaps the conductor film, and the conductor film on the transfer sheet is transferred to the component body and fixed. The feature is that this is used as an external electrode.

According to the method of forming an external electrode according to the first aspect of the present invention, after a conductor is wound around the surface of the component so as to overlap with the end of the internal circuit and fastened, an unnecessary portion of the wound conductor is removed, so that the surface of the component is removed. The external electrodes having a width corresponding to the thickness of the conductive wire can be formed at a pitch corresponding to the winding interval.

According to the third aspect of the present invention, the component main body is relatively pressed against the transfer sheet so that the internal circuit end overlaps the conductive film, and the conductive film on the transfer sheet is pressed against the component. By transferring and fixing to the main body, the external electrodes can be formed on the component surface in the same shape and pitch as the conductor film formed on the transfer sheet.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] FIGS. 1 and 2 relate to a first embodiment of the present invention. FIG.
FIG. 3 is a diagram showing an example of the shape of a conductive wire.

In FIG. 1 (a), reference numeral 1 denotes a component body serving as an inductor array, which is made of a magnetic material such as ferrite porcelain.
Although not shown, four coils are built in the component body 1 at intervals in the longitudinal direction similarly to the inductor array shown in FIG. 4, and the edge 2 of each coil is the width of the component body. It is derived on each of the two sides of the direction.

When the external electrodes are formed on the surface of the component body 1, first, as shown in FIG. 1B, the external electrodes are overlapped with the leading edge 2 of each coil along four side faces excluding the longitudinal side faces. The adhesive 3 is applied in a strip shape. This adhesive can be cured by applying heat, and is made of, for example, a known conductive paste that can be fired or a thermosetting conductive adhesive. The method of applying the adhesive is performed by applying the adhesive supplied to the outer peripheral edge of the thin rotating plate to the surface of the component using the thin rotating plate, or applying the adhesive supplied to the peripheral surface of the small diameter wire to the small diameter wire. And a method of applying it to the surface of a component by using the same.

Next, as shown in FIG. 1C, each part of the component body 1 to which the adhesive 3 has been applied
A conductive wire 4 having a circular cross section as shown in FIG. The conductor 4 is made of a metal material suitable for an external electrode, for example, silver,
It is made of nickel, silver-palladium or the like. Then, heat is applied to at least the conductor winding portion to cure the adhesive 3 and fix the conductor 4 to the component body 1. The heat application,
In addition to the method of putting the component main body 1 after the conductor winding into the heating furnace, a method of irradiating a laser beam in the infrared region along the conductor winding portion or the like is adopted.

Next, as shown in FIG. 1D, the central portion CA of the upper and lower surfaces of the winding wire 4 is removed by using a dicing device equipped with a diamond blade or a laser scribing device. As a result, a part of the winding wire 4 remains on the two side surfaces in the width direction of the component body 1 and the upper and lower surface portions adjacent to the side surfaces, and these become the external electrodes 5. Incidentally, the lead-out edge 2 of each coil in the component body 1 is connected to the external electrodes 5 facing each other in the width direction via the adhesive 3.

As described above, according to the above-described method for forming an external electrode, the conductive wire 4 is wound around the surface of the component so as to overlap with the leading edge 2 of the internal coil, and then the unnecessary portion of the wound conductive wire 4 is removed. Thus, the external electrodes 5 having a width corresponding to the thickness of the conductive wire 4 can be formed on the surface of the component at a pitch corresponding to the winding interval, which is extremely effective when forming fine external electrodes at a narrow pitch. .

In the above-described first embodiment, a conductor having a circular cross section is exemplified as the conductor, but a conductor 6 having a semicircular cross section as shown in FIG. 2B or a conductor 6 shown in FIG. By using such a conducting wire 7 having a rectangular cross section, the shape of the external electrode formed on the component surface can be arbitrarily selected.

In the above-described first embodiment, an example in which the conductor is fixed to the component body by bonding is described as an example. However, if the surface of the conductor is wound by application of heat to melt the surface, an adhesive may be used. Alternatively, the conductor can be directly fixed to the component body by welding.

Further, in the above-described first embodiment, an example in which the conductor is wound in parallel on the surface of the component is exemplified. However, the external electrode may be similarly wound even if it is spirally wound and fixed to remove unnecessary portions. Can be formed.

[Second Embodiment] FIG. 3 is a view showing a procedure for forming external electrodes according to a second embodiment of the present invention. The first
Portions having the same configuration as the embodiment are denoted by the same reference numerals, and description thereof is omitted.

When an external electrode is formed on the surface of the component body 1, first, as shown in FIG. 3A, a transfer sheet 11 made of a flexible film material such as PET is placed on the transfer sheet 11 in the width direction of the component body 1. The four external electrode conductor films 12 to be provided on one side face are formed in a band shape at intervals. The conductive film 12 is made of a known conductive paste that can be fired, and is formed by a technique such as a screen printing method.

Next, as shown in FIG. 3B, the component main body 1 is transferred to the transfer sheet 11 such that each of the coil leading edges 2 on one side in the width direction of the component main body 1 overlaps with each conductor film 12.
At the same time, the transfer sheet 11 is bent, and both end portions of each conductive film 12 are pressed against the upper and lower surfaces adjacent to the side surface, thereby transferring the conductive film 12 on the transfer sheet 11 to the component body 1. Similarly, using the same transfer sheet 11 as in FIG. 3A, the transfer of the conductor film 12 to the other side surface in the width direction of the component body 1 is performed in the same manner.

Next, the component body 1 after the transfer of the conductive film is put into a heating furnace, or a laser beam in the infrared region is irradiated along the transferred conductive film 12 to sinter the conductive film 12.
As a result, as shown in FIG. 3C, the conductor film 12 is hardened and fixed to the component body 1, which becomes the external electrode 13. Incidentally, the leading edge 2 of each coil in the component body 1 is connected to each of the external electrodes 13 facing each other in the width direction.

As described above, according to the above-described external electrode forming method, the component main body 1 is pressed against the transfer sheet 11 so that the leading edge 2 of the internal coil overlaps the conductive film 12, and the conductor on the transfer sheet 11 is pressed. By transferring the film 12 to the component main body 1 and fixing the same, the external electrodes 13 can be formed on the component surface in the same shape and pitch as the conductive film 12 formed on the transfer sheet 11, and a fine external electrode 13 can be formed. This is extremely effective when the electrodes are formed at a narrow pitch.

In the above-described second embodiment, an example is described in which the strip-shaped conductor film is transferred to the component body and this is used as the external electrode. However, the shape of the conductor film formed on the transfer sheet may be changed. Thus, external electrodes of various shapes other than the band shape can be formed on the surface of the component.

In the above-described second embodiment, a conductor film made of a conductive paste that can be printed has been described as an example. However, a metal film formed by a thin film method such as sputtering is used as the conductor film, and the conductor film for the component body is used. The metal film may be fixed by adhesion or welding similar to that described in the first embodiment.

As described above, in the first embodiment and the second embodiment, examples in which the present invention is applied to an inductor array having a plurality of built-in coils, respectively, are described. Also, the present invention can be widely applied to chip components such as chip inductors, chip capacitors, chip resistors, and the like, and similar effects can be obtained.

[0029]

As described above in detail, according to the first aspect of the present invention, after a conductor is wound around a surface of a component so as to overlap with an edge of an internal circuit, the unnecessary portion of the wound conductor is removed. Further, external electrodes having a width corresponding to the thickness of the conductive wire can be formed on the component surface at a pitch corresponding to the winding interval, which is extremely effective when forming fine external electrodes at a narrow pitch.

According to the third aspect of the present invention, the component body is pressed against the transfer sheet so that the internal circuit end overlaps the conductive film, and the conductive film on the transfer sheet is transferred to the component body and fixed. This allows the external electrodes to be formed on the component surface in the same shape and pitch as the conductor film formed on the transfer sheet, which is extremely effective when forming fine external electrodes at a narrow pitch.

[Brief description of the drawings]

FIG. 1 is a view showing a procedure for forming an external electrode according to a first embodiment of the present invention.

FIG. 2 is a view showing an example of the shape of a conductive wire;

FIG. 3 is a diagram showing a procedure for forming an external electrode according to a second embodiment of the present invention.

FIG. 4 is a transparent perspective view of an inductor array showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Part main body, 2 ... Coil leading edge, 3 ... Adhesive, 4 ...
Conducting wire, 5: external electrode, 6, 7: conducting wire, 11: transfer sheet, 12: conductive film, 13: external electrode.

Claims (5)

[Claims] 1. A method for forming an external electrode on an electronic component, wherein an external electrode is formed on the surface of the component so as to be electrically connected to an end of the internal circuit led to the surface of the component. A method for forming an external electrode of an electronic component, comprising: after winding and fixing, removing an unnecessary portion of the wound conductive wire and using the remaining portion as an external electrode. 2. The method for forming an external electrode of an electronic component according to claim 1, wherein the fixing of the conductive wire to the component main body is performed by welding or bonding. 3. A method for forming an external electrode on an electronic component, wherein an external electrode is formed on the surface of the component so as to be electrically connected to an end of an internal circuit led to the surface of the component. The component body is pressed relatively to the transfer sheet so that the internal circuit end overlaps the conductor film, and the conductor film on the transfer sheet is transferred to the component body and fixed, and this is used as an external electrode. A method for forming an external electrode of an electronic component. 4. The electronic component according to claim 3, wherein the conductive film formed on the transfer sheet is made of a printable conductive paste, and the fixing of the conductive film to the component body is performed by applying heat. External electrode formation method. 5. The external electrode of an electronic component according to claim 3, wherein the conductive film formed on the transfer sheet is a metal film, and the fixing of the conductive film to the component body is performed by welding or bonding. Method.