JPH0748410B2 - Method for forming electrode film in electronic component - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a film in which an electrode for connection is applied in a film form to an insulating substrate, such as a chip resistor and a chip capacitor. The present invention relates to a method for coating and forming the film-shaped electrode, that is, the electrode film, on the insulating substrate in the configured electronic component.

[Conventional technology]

Generally, when the electrode provided on the insulating substrate is formed into a film, the film-shaped electrode, that is, the electrode film is formed by coating on the upper surface of the insulating substrate so as to be electrically connected to the resistance film or the like on the upper surface. A top surface electrode film, a bottom surface electrode film formed by coating on the bottom surface of the insulating substrate, and a side surface electrode formed by coating the side surface of the insulating substrate so that the top surface electrode film and the bottom surface electrode film are electrically connected to each other. It is composed of a membrane.

However, if these upper surface electrode film, lower surface electrode film and side surface electrode film are separately formed by coating on each of the insulating substrates, the productivity will be remarkably low and the manufacturing cost will increase significantly. Conventionally, coating is performed by the method described below.

That is, for example, in the case of a chip resistor, first,
As shown in FIG. 14 and FIG. 15, the insulating material plates a made of ceramic are arranged on the upper surface and the lower surface of the insulating material plate a in a state where a plurality of insulating substrates 11 are arranged in the vertical and horizontal directions. Each insulating substrate 11 is formed by forming vertical streak grooves a1 and transverse streak grooves a2 having a V-shaped cross section for breaking, and at the locations of the horizontal streak grooves a2 on the lower surface of the insulating material plate a, as shown in FIG. 17
As shown in the figure, a conductive paste for the lower surface electrode film is applied by screen printing so as to be continuous across both of the two insulating substrates 11 adjacent to each other with the horizontal groove a2 interposed therebetween and then dried. While forming the lower surface electrode film 12b,
At the location of the horizontal streak grooves a2 on the upper surface of the insulating material plate a,
As shown in FIGS. 18 and 19, similarly to the above, the conductive paste for the upper surface electrode film is continuously spread over both of the two insulating substrates 11 adjacent to each other with the horizontal groove a2 interposed therebetween by screen printing. After the upper electrode film 2a is formed by applying and drying as described above, the upper surface of the insulating material plate a is coated with a resistor as shown in FIGS. A film 13 is formed by coating, and then the insulating material plate a is bent along a transverse groove a2 to break it into a rod-shaped insulating material plate a3 as shown in FIGS. 22 and 23. Each insulating substrate 11 on the rod-shaped insulating material plate a3
As shown in FIG. 25, the conductive paste for the side surface electrode film is applied to the left and right side surfaces 11a of the electrode 11 and dried to form the side surface electrode film 12c. A membrane 12 is provided, after which this rod-shaped insulating material plate a3
By breaking each of the insulating substrates 11 along the vertical groove a1, the chip resistor is manufactured.

[Problems to be Solved by the Invention]

However, in this conventional method of forming the electrode film 12 by coating, both the upper surface electrode film 12a and the lower surface electrode film 12b are placed in the horizontal groove groove a2 in the insulating material plate a, and the conductive paste is applied to the horizontal stripe groove. It is formed by coating so as to be continuous over both of the insulating substrates 11 adjacent to each other with a2 sandwiched therebetween, and thus, is formed so as to be continuous over both of the insulating substrates 11 as described above. Conductive paste is vertical groove
While being applied to the groove surface a2 'in a1 as well, since the conductive paste will flow into the horizontal groove a2 until it is dried, the upper electrode film 12a and the lower electrode film 12b of the upper electrode film 12a As shown in FIG. 19, the film thickness in the portion of the horizontal groove a2 is considerably thicker than the film thickness in the upper surface and the lower surface of the insulating substrate 11.

That is, two insulating substrates adjacent to each other with the vertical groove a1 sandwiched therebetween.
11 is in a state of being connected to each other by the upper surface electrode film 12a and the lower surface electrode film 12b whose film thickness is mixed in the portion in the horizontal groove a2, and the film thickness in the upper surface electrode film 12a and the lower surface electrode film 12b is The thickening in the transverse groove a2 means that the insulating material plate a is bent along the transverse groove a2 by bending it by applying an external force in the directions shown by arrows b and b in FIG. Since the workability of the break is low because it remarkably hinders, moreover, at the time of breaking, the insulating material plate a is broken at a position deviated from the center (the deepest part) of the transverse groove a2, and each insulating substrate 11 is broken. The yield rate of the product is low because chipping occurs.

In addition, when the insulating material plate a is broken by applying an external force in the directions of the arrows b, b as described above, the arrows b, b of the upper electrode film 12a and the lower electrode film 12b are
Since the lower surface electrode film 2b located on the inner side with respect to the bending direction shown by b is broken by the compressive force,
Although it will be broken at the center of a2,
Of the upper surface electrode film 12a and the lower surface electrode film 12b, the upper surface electrode film 2a located outside in the bending direction shown by arrows b, b.
Since the film is broken by the tensile force, the film thickness of the upper surface electrode film 12a that is broken by the tensile force is thick in the transverse groove a2 means that the upper surface electrode film 12a is As shown in the figure, the upper electrode film 12 on one insulating substrate 11 of the two insulating substrates 11 is broken at a position deviated from the center of the transverse groove a2.
a is a form in which the groove surface a2 ′ portion in the transverse groove a2 of the upper surface electrode film 12a is baldly dropped, while the upper surface electrode film 12a on the other insulating substrate 11 of both insulating substrates 11 is formed.
Is in a form projecting from the side surface 11a of the other insulating substrate 11, and further, a portion of the upper surface electrode film 12a of the other insulating substrate 11 projecting from the side surface 11a is under handling such as transfer of an insulating material plate. In, as shown in FIG.
Since it will be chipped off from the insulating substrate 11, the upper surface electrode film 12a on the other insulating substrate 11 also has a form that is baldly dropped from the groove surface a2 'in the horizontal groove a2.

Therefore, when the side surface electrode film 12c is formed by applying a conductive paste to the side surface 11a of the insulating substrate 11, the top surface electrode film 12a of the side surface electrode film 12c is formed.
As shown in FIG. 25, the film thickness at the groove surface a1 ′ where the baldness has fallen is extremely thin. Therefore, when mounting the chip resistor on a printed circuit board or the like, the electrode film 12
When soldering to a printed circuit board, so-called soldering (the side electrode film 12c is carried away by the molten solder) may occur in a thin film portion of the side electrode film 12c of the electrode film 12. Occurs,
In particular, this solder shaving occurs remarkably when the width dimension of the upper surface electrode film 12a is made narrower than the width dimension of the insulating substrate 11, as shown in the drawing.

In addition, the above-mentioned inconvenience is
It also occurred when the external force was applied in the opposite direction to b and b to break.

An object of the present invention is to provide a method for forming an electrode film, which solves the problems of the above-described conventional method for forming an electrode film.

[Means for Solving the Problems]

In order to achieve this object, the present invention provides an insulating material plate in which a plurality of insulating substrates are arranged in the vertical and horizontal directions.
The insulating material plate is formed by forming a groove having a V-shaped cross section for breaking each insulating substrate on the upper surface and the lower surface of the insulating material plate, and the conductive material for the upper surface electrode film is formed on the upper surface and the lower surface of each insulating substrate of the insulating material plate. Conductive paste and conductive paste for the lower surface electrode film are respectively applied and dried, and then the insulating material plate is bent along the crease grooves to break it into a rod-shaped insulating material plate. In the method for forming an electrode film, which comprises applying a conductive paste for a side surface electrode film connecting the upper surface electrode film and the lower surface electrode film to the side surface of each insulating substrate, and then drying the same, the upper surface of the insulating material plate When the conductive paste for the upper surface electrode film and the conductive paste for the lower surface electrode film are applied to the lower surface of the insulating material plate and the conductive paste for the upper surface electrode film and the lower surface electrode film, respectively. Of the conductive paste, at least one conductive paste for the surface that becomes the outside of the bending at the time of breaking by the bending is applied so as to be continuous across both of the two insulating substrates adjacent to each other with the line groove interposed therebetween. Without doing so, it was decided to apply it so as to be divided at the positions of the groove lines.

[Work]

Conductive paste for the upper surface electrode film on the upper surface of the insulating material plate,
When applying the conductive paste for the lower surface electrode film to the lower surface of the insulating material plate, at least one of the conductive paste for the upper surface electrode film and the conductive paste for the lower surface electrode film, which is formed by bending At that time, apply one conductive paste to the outside surface of the fold,
If it is configured to be applied so as to be divided at the position of the groove, without being applied so as to be continuous across both of the two insulating substrates that are adjacent to each other across the groove.
This one conductive paste, without being applied to the groove surface in the crease groove, will drip toward the crease groove until the one conductive paste dries, A film can be formed on the groove surface of the groove by the one conductive paste, and
Since the thickness of the film at the deepest portion in the groove line can be made extremely thin, or the electrode film can be prevented from being formed at the deepest portion in the groove line. is there.

〔The invention's effect〕

Therefore, according to the present invention, when the insulating material plate is broken along the groove lines into the rod-shaped insulating material plate, one of the upper surface electrode film formed by coating on the upper surface and the lower surface electrode film formed by coating on the lower surface is formed. On the other hand, since it is possible to reduce the inhibition of the break along the score groove, it is possible to significantly improve the workability of breaking the insulating material plate along the score groove, and the insulating material plate, Since it is possible to reduce breakage at a position deviated from the center of the groove line, that is, the occurrence of chipping in the insulating substrate, the yield rate of products can be significantly improved.

Moreover, under the condition that a film is formed on the groove surface of the groove line, the film thickness in the deepest part of the groove line can be made extremely thin or can be made zero.
It is possible to prevent the portion of the upper surface electrode film or the lower surface electrode film at the groove surface portion in the groove line from falling down from the groove surface at the time of the above-mentioned break. The conductive paste or the conductive paste for the lower surface electrode film and the conductive paste for the side surface electrode film coated on the side surface can be formed into a double-layered film, in other words, by bending the insulating material plate. At the time of breaking, it is possible to prevent the electrode film on the groove surface of the groove line located on the outer side of the bending from being thinned, so that it is possible to reliably reduce the occurrence of solder breakage at the time of soldering.

〔Example〕

Hereinafter, the embodiment of the present invention will be described with reference to the first of the chip resistors.
As shown in FIG. 2 and FIG. 2, for a pair of electrodes formed on the upper surface of the insulating substrate 1 so as to form a resistance film 3 concentrically with the central hole 2 and project on the side surface of the insulating substrate 1. Protrusion 4
And a rotor member 6 slidably contacting the resistance film 3 is rotatably attached to a shaft 7 inserted through the center hole 2 in a chip type. A case where the present invention is applied to a variable resistor will be described. In this case, the electrode film 5 is composed of an upper surface electrode film 5a on the upper surface of the insulating substrate 1, a lower surface electrode film 5b on the lower surface of the insulating substrate 1, and a side surface electrode film 5c on the side surface of the insulating substrate 1. .

In FIG. 3, reference numeral A denotes a ceramic insulating material plate, and the insulating material plate A has a plurality of insulating substrates 1 so that the electrode projections 4 on the insulating substrate 1 face outward. The three rod-shaped insulating material plates A1 arranged in rows are integrally connected to each other at the electrode projections 4 of each insulating substrate 1 of these three rod-shaped insulating material plates A1. The ear pieces A2, A3 having notches A4, A5 for positioning are integrally connected to each other, and each of the isolation boards 1 and the insulating board 1 and the two ear pieces A2, A3 are connected to each other. Between them, as shown in FIG. 4, longitudinal groove grooves A6 and A7 having a V-shaped cross section are provided on both the upper surface and the lower surface of the insulating material plate A.

With the lower surface of the insulating material plate A turned upside down, on the lower surface of the insulating material plate A, at the locations of the electrode projections 4 on each insulating substrate 1, as shown in FIGS.
As shown in the figure, a conductive paste for the lower surface electrode 5b is screen-printed on both of the two insulating substrates 1 adjacent to each other across the horizontal groove A7 so as to be continuous over the electrode projections 4. Then, by drying, the bottom electrode film 5b
To form.

Next, with the upper surface of the insulating material plate A facing upward, each insulating substrate 1 on the upper surface of the insulating material plate A.
When the conductive paste for the upper surface electrode film 5a is applied by screen printing to the place of the electrode projection 4 in the above, the conductive paste for the upper surface electrode film 5a is adjacent to the electrode projection 4 with the transverse groove A7 interposed therebetween. As shown in FIG. 7 and FIG. 8, without being continuously applied over the electrode projections 4 on both of the two insulating substrates 1, as shown in FIG. 7 and FIG. In other words, the upper surface electrode film 5a is formed by separately coating the electrode protrusions 4 and drying. In this case, the upper surface electrode film 5a
Is formed so as to fill the width of the electrode projection 4 on each insulating substrate 1.

When these are finished, on the upper surface of the insulating material plate A, at the location of each insulating substrate 1, as shown in FIGS. 9 and 10,
The resistance film 3 is formed by applying a paste for the resistance film 3 by screen printing and then drying.

After that, the insulating material plate A is shown in FIG.
By bending by applying an external force in the direction indicated by
As shown in FIG. 11 and FIG. 12, each rod-shaped insulating material plate A1 is broken along the transverse groove A7, and then the tip end portion of the electrode projection 4 on each insulating substrate 1 of this rod-shaped insulating material plate A1 is broken. As shown in FIG. 13, a conductive paste for the side surface electrode film 15c is applied to the side surface 4a over the width of the electrode projection 4 by screen printing or the like, and dried to form a side surface electrode film. Form 5c.

Incidentally, each of the rod-shaped insulating material plate A1, after forming the side surface electrode film 5c, along the longitudinal groove A6 and the horizontal groove A7,
Each insulating substrate 1 is broken.

Then, as described above, the upper surface electrode film is formed on the upper surface of the insulating material plate A at the position of the electrode projection 4 on each insulating substrate 1.
In applying the conductive paste for 5a by screen printing, the present invention is characterized in that the insulating material plate A is
When breaking by bending along A7, the upper surface electrode film 5a for the outer surface of the bending
At the location of the horizontal groove A7 without applying the conductive paste for use continuously over the electrode projections 4 on both of the two insulating substrates 1 adjacent to each other with the horizontal groove A7 interposed therebetween. The conductive paste applied to the upper surfaces of the electrode projections 4 on each insulating substrate 1 hangs down in the horizontal groove groove A7. The upper surface electrode film 5a formed by coating on the groove surface A7 'has a thickness gradually decreasing toward the deepest portion of the transverse groove A7, as shown in FIG.

That is, according to the present invention, the groove surface A in the transverse groove A7
Although the upper surface electrode film 5a can be formed on 7 ', the thickness of the groove surface A7' can be gradually thinned toward the deepest part of the transverse groove A7, In other words, the groove surface A7 ′ in the transverse groove A7
Under the condition that the film is formed in, the thickness of the film in the deepest part in the transverse groove A7 can be made extremely thin, or in the deepest part in the transverse groove A7,
No film can be formed.

Therefore, when breaking along the transverse groove A7,
Since the upper surface electrode film 5a can reduce the inhibition of the break along the transverse groove A7, the workability of breaking the insulating material plate A along the transverse groove A7 can be significantly improved. At the same time, it is possible to prevent the insulating material plate A from breaking at a position removed from the center of the transverse streak groove A7.

Further, as described above, since the film thickness at the deepest portion in the transverse groove A7 can be made extremely thin or can be made zero, the upper surface electrode film 5a at the time of the above break.
It is possible to prevent the portion of the transverse groove A7 at the groove surface A7 'from falling down from the groove surface A7'.

As a result, when the conductive paste for the side surface electrode film 5c is applied to the tip end side surface 4a of the electrode projection 4 in each insulating substrate 1, the groove surface A7 'in the transverse groove A7 has a surface shown in FIG. As shown in, it is possible to form a two-stage film of the conductive paste for the upper surface electrode film 5a applied on the upper surface and the conductive paste for the side surface electrode film 5c applied on the side surface, It is possible to prevent the side surface electrode film 5c from being partially thinned at the position of the groove surface A7 '.

Incidentally, in the above-mentioned embodiment, of the conductive paste for the upper surface electrode film 5a and the conductive paste for the lower surface electrode film 5b, only the conductive paste for the upper surface electrode film 5a is divided at the position of the horizontal groove A7. Although the case of coating is shown as described above, the present invention is not limited to this, and in the case of breaking the insulating material plate A by applying an external force in a direction opposite to the direction of the arrows B, B, ,
Only the conductive paste for the lower surface electrode film 5b may be applied so as to be divided at the position of the horizontal groove A7, and of course, the conductive paste for the upper surface electrode film 5a and the lower surface electrode film 5b.
Both of the conductive pastes for use may be applied so as to be divided at the positions of the horizontal groove A7.

[Brief description of drawings]

FIG. 1 is a plan view of a chip type variable resistor, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIGS. 3 to 13 are views showing an embodiment of the present invention. Is a plan view of the insulating material plate, FIG. 4 is an enlarged sectional view taken along line IV-IV of FIG. 3, FIG. 5 is a plan view when the conductive paste for the lower surface electrode film is applied, and FIG. VI-VI enlarged cross-sectional view of FIG. 7, FIG. 7 is a plan view when the conductive paste for the upper surface electrode film is applied, and FIG. 8 is VIII of FIG.
-VIII enlarged cross-sectional view, FIG. 9 is a plan view when a resistance film is applied, FIG. 10 is an enlarged cross-sectional view taken along line XX of FIG. 9, and FIG. 11 is broken for each rod-shaped insulating material plate. When the plan view, No.
12 is an enlarged cross-sectional view taken along the line XII-XII in FIG. 11, FIG. 13 is an enlarged cross-sectional view when a conductive pace for a side electrode film is applied, and FIG.
FIG. 25 is a diagram showing a conventional method, FIG. 14 is a plan view of an insulating material plate, FIG. 15 is an enlarged sectional view taken along line XV-XV of FIG. 14,
Figure 16 is a plan view of the bottom electrode film applied, and Figure 17 is a plan view.
FIG. 16 is an enlarged cross-sectional view taken along line XVII-XVII, FIG. 18 is a plan view when the upper electrode film is applied, FIG. 19 is an enlarged cross-sectional view taken along line XIX-XIX of FIG. 18, and FIG. 20 is a resistance film. Top view of the painted
FIG. 21 is an enlarged sectional view taken along the line XXI-XXI of FIG. 20, FIG. 22 is a plan view when breaking each rod-shaped insulating material plate, and FIG.
22 is an enlarged sectional view taken along line XXIII-XXIII of FIG. 24, FIG. 24 is another sectional view of FIG. 23, and FIG. 25 is an enlarged sectional view taken along line XXV-XXV of FIG. 1 ... Insulating substrate, 3 ... Resistive film, 4 ... Electrode protrusion, 5
...... Electrode film, 5a …… Upper surface electrode film, 5b …… Lower surface electrode film, 5c
...... Side electrode film, 6 ...... Rotor member, A …… Insulation material plate, A1 …… Bar-shaped insulation material plate, A6, A7 …… Score groove.

Claims (1)

[Claims] 1. A cross-section V for breaking an insulating material plate in which a plurality of insulating substrates are arranged in the vertical and horizontal directions for each insulating substrate on the upper surface and the lower surface of the insulating material plate.
Formed by forming a groove line of the mold, the conductive paste for the upper surface electrode film and the conductive paste for the lower surface electrode film are respectively applied to the upper surface and the lower surface of each insulating substrate in the insulating material plate, and then dried. Then, the insulating material plate is bent along the grooves to break it into a rod-shaped insulating material plate, and the side surface of each insulating substrate in the rod-shaped insulating material is a side surface connecting the upper surface electrode film and the lower surface electrode film. In the method of forming an electrode film, which comprises applying a conductive paste for an electrode film and then drying it, a conductive paste for an upper surface electrode film is formed on an upper surface of the insulating material plate, and a lower surface electrode film is formed on a lower surface of the insulating material plate. When applying the conductive paste for each of the above, when at least one of the conductive paste for the upper surface electrode film and the conductive paste for the lower surface electrode film is folded at the time of break due to the bending. One conductive paste for the surface that is the outside of the bending is divided so as to be divided at the position of the groove groove without being applied so as to be continuous over both of the two insulating substrates adjacent to each other with the groove groove interposed therebetween. A method for forming an electrode film in an electronic component, which comprises applying the electrode film as described above.