JPH02207501A - Method of forming electrode film in electronic parts - Google Patents

Abstract

PURPOSE:To reduce generation of chips in an insulating substrate so as to improve the yield rate of a product by applying conductive paste at least in one hand between conductive pastes for electrode films apart at a plate of the groove of two insulating substrates which adjoin each other. CONSTITUTION:When applying, by screen printing, conductive paste for a top electrode film 5a on the place of a projection 4 for electrode in each insulating substrate 1 with the top side of the insulating material plate A up, this conductive paste for top electrode film 5a is applied separately on each projection 4 for electrode so that it may be divided by lateral groove A7, without being applied so that it may continue astride the projections for electrodes in both of the two insulating substrates 1 which adjoin each other with the lateral groove A7 between, so as to form top electrode films 5a. After these are finished, a resistance film 3a is formed at a place of each insulating substrate 1 with the paste for resistance film 3 by screen printing. Thereafter, the insulating material plate A is broken along the lateral groove A7 into each bar-shaped insulating material plate A1 by adding external force in the direction shown by arrows B and B so as to bend it.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to devices such as chip resistors and chip capacitors in which connection electrodes are coated in a film form on an insulating substrate. The present invention relates to a method for coating and forming the film-like electrode, that is, the electrode film, on the insulating substrate in the configured electronic component.

[Conventional technology]

Generally, when an electrode provided on an insulating substrate is formed into a film, the film-like electrode, that is, the electrode film is formed by coating on the upper surface of the insulating substrate so as to be electrically conductive to a resistive film, etc. on the upper surface. a top electrode film coated on the bottom surface of the insulating substrate, a bottom electrode film coated and formed on the bottom surface of the insulating substrate, and a side electrode film coated and formed on the side surface of the insulating substrate so that the top electrode film and the bottom electrode film are electrically connected to each other. It is composed of

However, if these top electrode films, bottom electrode films, and side electrode films were formed by coating separately on each insulating substrate, productivity would be extremely low and manufacturing costs would increase significantly. Conventionally, the coating is formed by the method described below.

For example, in the case of a chip resistor, first, as shown in FIGS. 14 and 15, a large number of insulating substrates 1 are
A cross section V for breaking a lying ceramic insulating material plate a in which a plurality of insulating substrates 1 are arranged in the vertical and horizontal directions on the upper and lower surfaces of the insulating material plate a for each insulating substrate 11.
A vertical groove a1 and a horizontal groove a2 are formed in the mold, and the horizontal groove a2 is formed on the lower surface of the insulating material plate a.
As shown in FIGS. 16 and 17, a conductive paste for the lower electrode film is applied to the horizontal grooves a by screen printing.
The lower surface electrode film 12b is formed by applying the coating continuously across both of the two adjacent insulating substrates 11 with the insulating substrates 11 in between and drying. As shown in FIGS. 18 and 19, in the same manner as described above, a conductive paste for the upper surface electrode film is applied by screen printing to both of the two adjacent insulating substrates 11 with the horizontal groove a2 in between. After forming the upper surface electrode film 2a by applying the film continuously across the insulating material plate a and drying it, it is applied to each insulating substrate 11 on the upper surface of the insulating material plate a as shown in FIGS. 20 and 21. like,
The resistive film 13 is applied and formed, and then, as shown in FIGS. 22 and 23, the insulating material plate a is broken into rod-shaped insulating material plates a3 along the horizontal grooves a2. Both left and right side surfaces 11 of each insulating substrate 11 on the material board a3
As shown in FIG.
After that, this rod-shaped insulating material plate a3 is
A chip resistor is manufactured by breaking each insulating substrate 11 along the vertical grooves a1.

[Problem to be solved by the invention]

However, in this conventional method of coating and forming the electrode film 12, both the upper electrode film 12a and the lower electrode film 12b are coated with a conductive paste at the horizontal grooves aa2 of the insulating material plate a. It is formed by applying the conductive material continuously across both insulating substrates 11 which are adjacent to each other with the conductive substrates 11 in between. The conductive paste is also applied to the groove surface a2' in the vertical groove al, and flows into the horizontal groove height a2 until the conductive paste dries. The thickness of the bottom electrode film 12b at the portion within the horizontal line height a2 is considerably thicker than the thickness at the top and bottom portions of the insulating substrate 11, as shown in FIG.

That is, the two insulating substrates 11 adjacent to each other with the vertical groove a1 in between are connected to each other by the upper surface electrode film 12a and the lower surface electrode film 12°b whose film thickness is thicker at the portion within the horizontal streak height a2. Therefore, the film thickness of the upper surface electrode film 12a and the lower surface electrode film 12b becomes thicker within the horizontal line height a2 when an external force is applied to the insulating material plate a in the direction shown by arrows b in FIG. By bending it, breaking along the horizontal groove a2 is significantly inhibited, and the workability of breaking is low.
Moreover, when breaking, the insulating material plate a is broken at a location away from the center (deepest part) of the horizontal groove a2, and each insulating substrate 11 is chipped, which reduces the yield rate of the product. It is low.

In addition, arrows 1 and 2 are attached to the insulating material plate a as described above.
When the upper electrode film 12a and the lower electrode film 12b are broken by applying an external force in the direction shown in FIG. Therefore, the break occurs at the center of the horizontal groove a2, but the upper surface electrode film 12a and the lower surface electrode film 12
Since the upper surface electrode film 2a located outside of the bending direction indicated by arrows b in b is broken by tensile force, the film thickness of the upper surface electrode film 12a that is broken by this tensile force is However, the Yokosuji Nissin a
As shown in FIG. The electrode film 12a has a groove surface a in the horizontal groove a2 of the upper electrode film 12a.
While the 2' part becomes bald, both insulating substrates 1
1, the upper surface electrode film 12a on the other insulating substrate 11
is in a form that protrudes from the side surface 11a of the other insulating substrate 11, and furthermore, the portion of the upper electrode film 12a of this other insulating substrate 11 that protrudes from the side surface 11a is removed during handling, such as transferring the insulating material board. In this case, as shown in FIG.
A also falls off from the groove surface a2' in the horizontal groove a2.

Therefore, by applying a conductive paste to the side surface 11a of the insulating substrate 11, the side electrode film 12c is
In this case, the thickness of the side electrode film 12c at the groove surface a1' where the upper electrode film 12a falls off becomes extremely thin, as shown in FIG.
When mounting the chip resistor on a printed circuit board or the like, when soldering the electrode film 12 to the printed circuit board, the side electrode film 1 of the electrode film 12
So-called solder cracks (where the side electrode film 12C is removed by the molten solder) occur in the thinner part of the film 2c, and in particular, the solder cracks are caused by the width dimension of the top electrode film 12a. As shown in the figure, this phenomenon occurs significantly when the width of the insulating substrate 11 is made narrower than the width of the insulating substrate 11.

Further, the above-mentioned problem also occurs when the insulating material plate a is subjected to an external force in the direction opposite to the arrows S and B.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming an electrode film that eliminates the disadvantages of the conventional electrode film forming methods described above.

[Means to solve the problem]

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.
A groove with a V-shaped cross section for breaking each insulating substrate is provided on the upper and lower surfaces of the insulating material plate, and conductive grooves for the upper electrode film are formed on the upper and lower surfaces of each insulating substrate in the insulating material plate. A conductive paste and a conductive paste for the bottom electrode film are respectively applied, and then the insulating material plate is temporarily broken into a bar-shaped insulating material along the grooves, and then a bar-shaped insulating material is applied to the side surface of each insulating substrate in this bar-shaped insulating material. , a method for forming an electrode film comprising applying a conductive paste for a side electrode film connecting the top electrode film and the bottom electrode film, the conductive paste for the top electrode film and the conductive paste for the bottom electrode film; The conductive paste on at least one of the conductive pastes is not applied continuously across both of the two adjacent insulating substrates with the groove in between, but is separated at the location of the groove. The structure was designed so that it can be applied after washing.

[For production]

Conductive paste for the top electrode film is applied to the temporary top surface of the insulating material.
When applying the conductive paste for the lower electrode film to the lower surface of the insulating material plate, at least one of the conductive paste for the upper electrode film and the conductive paste for the lower electrode film is applied. If the structure is such that the coating is not applied continuously across two adjacent insulating substrates with the grooves in between, but is applied in a manner that separates the substrates at the grooves, the conductivity of one of the substrates can be increased. The conductive paste is not applied to the groove surface of the groove, but drips into the groove until the one conductive paste dries. In addition, it is possible to form a film using the one conductive paste, and the thickness of the film at the deepest part of the groove can be made extremely thin, or the thickness of the film at the deepest part of the groove can be made extremely thin. This makes it possible to completely eliminate the formation of an electrode film on the area.

〔Effect of the invention〕

Therefore, according to the present invention, when an insulating material plate is broken into rod-shaped insulating material plates along the grooves, either of the upper surface electrode film coated and formed on the upper surface and the lower surface electrode film coated and formed on the lower surface. On the other hand, it is possible to reduce the inhibition of breaking along the grooves, so that the workability of breaking the insulating material plate along the grooves can be greatly improved, and the insulating material plate can be Since it is possible to reduce the occurrence of breaks at locations away from the center of the grooves, that is, the occurrence of chips in the insulating substrate, the yield rate of products can be significantly improved.

Moreover, "C" in a state where a film is completely formed in the grooves.
In L, the film thickness at the deepest part in the groove can be made extremely thin or zero, so that the portion of the upper electrode film or the lower electrode film at the groove surface in the groove can be made extremely thin or even zero. , it is possible to prevent baldness from falling off the groove surface when the break occurs, and therefore, the film on this full surface area is coated on the side surface with a conductive paste for the top electrode film or a conductive paste for the bottom electrode film. It can be made into a two-layered film with conductive paste for the side electrode film.In other words, when the insulating material plate is bent and broken, the electrode film on the groove surface of the groove located on the outside of the bending is Since thinning can be prevented, it is possible to reliably reduce the occurrence of solder cracks during soldering.

〔Example〕

Hereinafter, the embodiments of the present invention will be explained as follows.
As shown in the figure and FIG. 2, a center hole 2 and a concentric circular resistance film 3 are formed on the upper surface of the insulating substrate 1, while a pair of electrodes are formed to protrude from the side surface of the insulating substrate 1. Electrode films 5 are formed on each of the resistive film 3 at both ends of the resistive film 3, and a rotor member 6 that comes into sliding contact with the resistive film 3 is rotatably attached to a shaft 7 inserted through the center hole 2. A case where the present invention is applied to a chip type variable resistor will be explained. In this case, the electrode film 5 is formed on an insulating substrate l.
It is composed of a top electrode film 5a on the top surface, a bottom electrode film 5b on the bottom surface of the insulating substrate 1, and a side electrode film 5c on the side surface of the insulating substrate 1.

In FIG. 3, reference numeral A indicates an insulating material plate made of ceramic, and the insulating material board A holds a large number of the insulating substrates 1 in such a way that the electrode protrusions 4 of the insulating substrate 1 face outward. Three rod-shaped insulating material plates Al arranged side by side are integrally connected at the location of the electrode protrusion 4 on each insulating substrate 1 of these three rod-shaped insulating material plates A1, and both ends thereof has an A4 notch for positioning.
゜Ear piece A2 with A5. A3 are integrally connected, and between the respective insulating substrates 1, and between each insulating substrate 1 and both ear pieces A2. As shown in FIG. 4, there is a vertical groove with a V-shaped cross section between A3 and A6. A7 is provided on both the upper and lower surfaces of the insulating material plate A.

With the insulating material plate A turned over so that the lower surface thereof faces upward, on the lower surface of the insulating material plate A, place the electrode protrusions 4 on each insulating substrate 1 as shown in FIGS. 5 and 6.
As shown in the figure, the conductive paste for the lower electrode film 5b is applied by screen printing so as to extend continuously over the electrode protrusions 4 on both of the two adjacent insulating substrates 1 with the horizontal groove A7 in between. By drying it after wearing it,
A lower surface electrode film 5b is formed.

Next, with the upper surface of the insulating material plate A facing upward, a conductive paste for the upper electrode film 5a is applied to the upper surface of the insulating material plate A at the location of the electrode protrusion 4 in each insulating substrate work. When applying this by screen printing, apply the conductive paste for the upper electrode film 5a so that it continues across the electrode protrusions 4 on both of the two adjacent insulating substrates 10 across the horizontal groove A7. In other words, it is applied to each electrode protrusion 4 separately so as to be divided at the horizontal groove A7 as shown in FIGS. 7 and 8 without being applied, and then dried. By this, the upper surface electrode film 5a is formed.

In this case, the upper surface electrode film 5a is formed to cover the entire width of the electrode protrusion 4 on each insulating substrate l.

After completing these steps, paste for the resistive film 3 was applied to the upper surface of the insulating material plate A at the location of each insulating substrate 1 by screen printing, as shown in FIGS. 9 and 10. The resistive film 3 is then formed by drying.

After that, the insulating material plate A is moved to the arrow B in FIG.
, by applying an external force in the direction shown by B and bending, each rod-shaped insulating material plate A1 breaks along the horizontal groove A7, as shown in FIGS. 11 and 12, and then this rod-shaped insulating material As shown in FIG. 13, on the side surface 4a of the tip end of the electrode protrusion 4 on each insulating substrate 1 of the plate A1,
A conductive paste for the side electrode film 15C is applied over the entire width of the electrode protrusion 4 by screen printing or the like, and dried to form the side electrode film 5C.

In addition, each rod-shaped insulating material plate A1 is connected to the side electrode film 5.
After forming the grooves C, each insulating substrate 1 is broken along the vertical grooves A6 and the horizontal grooves A7.

As described above, when applying the conductive paste for the upper surface electrode film 5a to the location of the electrode protrusion 4 on each insulating substrate 1 on the upper surface of the insulating material plate A by screen printing, the present invention , without applying the conductive paste for the upper surface electrode film 5a continuously across the electrode protrusions 4 on both of the two adjacent insulating substrates 1 with the horizontal groove A7 in between. This is because the conductive paste applied to the upper surface of the electrode protrusion on each insulating substrate 1 will drip into the transversely grooved groove A7 because it is applied so as to be divided at the groove A7. ,
As shown in FIG. 8, the upper surface electrode film 5a coated and formed on the entire surface A7' of the horizontal groove A7 has a film thickness that gradually becomes thinner toward the deepest part of the horizontal groove A7. Become.

That is, according to the present invention, the full surface A? in the transverse groove A7? Although the upper surface electrode film 5a can be formed on the full surface A? The film thickness at ' can be made to gradually become thinner toward the deepest part in the horizontal groove A7, in other words, under the state where the film is formed on the full surface A7' in the horizontal groove A7, The thickness of the membrane at the deepest part in the transverse groove A7 can be made extremely thin, or
It is possible to completely eliminate the formation of a film in the deepest part of the inside of the 7.

Therefore, when breaking along the horizontal groove A7, the upper surface electrode film 5a can reduce the inhibition of the break along the horizontal groove A7, so that the insulating material plate can be exposed to the horizontal groove A7. The workability of breaking along the groove A7 can be greatly improved, and the insulating material plate A can be prevented from breaking at a location away from the center of the horizontal groove A7.

In addition, since the film thickness at the deepest part of the horizontal groove A7 can be made extremely thin or zero as described above, when the upper electrode film 5a is broken, the horizontal groove A7 of the upper surface electrode film 5a It is possible to prevent a portion of the groove surface A7' from falling off from the groove surface A7'.

As a result, when the conductive paste for the side electrode film 5C is applied to the side surface 4a of the tip end of the electrode protrusion 4 on each insulating substrate 1, the full surface A? ', as shown in FIG. Since the side electrode film 5C can be formed on the groove surface A? It is possible to prevent partial thinning at the point '.

In addition, in the above embodiment, of the conductive paste for the upper electrode film 5a and the conductive paste for the lower electrode film 5b, only the conductive paste for the upper electrode film 5a is separated at the horizontal line mA1. However, the present invention is not limited to this, and the insulating material plate A is applied in the direction indicated by the arrow 8.
．． When breaking by applying an external force in the direction opposite to the direction of B, only the conductive paste for the bottom electrode film 5b is applied.
It is sufficient to apply the paste so as to separate it at the horizontal groove A7, and of course, both the conductive paste for the upper electrode film 5a and the conductive paste for the lower electrode film 5b are applied at the horizontal groove A7. It is also possible to apply it by dividing it into parts.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a chip type variable resistor, FIG. 2 is a sectional view taken along the line nn in FIG. 1, and FIGS. 3 to 13 are views showing embodiments of the present invention. 4 is a plan view of the insulating material plate, FIG. 4 is a wide enlarged cross-sectional view taken along the line IV-IV in FIG. 3, and FIG. Fig. 7 is a plan view when the conductive paste for the top electrode film is applied, Fig. 8 is an enlarged sectional view of Fig. 7, and Fig. 9 is an enlarged sectional view of the resistor. A plan view when the film is applied, FIG. 10 is an enlarged sectional view taken along line XX in FIG. 9,
Fig. 11 is a plan view when each rod-shaped insulating material plate is broken, Fig. 12 is an enlarged cross-sectional view of xn-x in Fig. 11, and Fig. 13 is an enlarged view when the conductive paste for the side electrode film is applied. 14 to 25 are cross-sectional views showing the conventional method, FIG. 14 is a plan view of the insulating material plate, and FIG.
XV-XV enlarged cross-sectional view in the figure. Figure 16 is a plan view when the bottom electrode film is applied. Figure 17 is X--X in Figure 16.
■ Widely enlarged cross-sectional view Figure 18 is a plan view when the top electrode film is applied, Figure 19 is an enlarged cross-sectional view from X-XIX in Figure 18, and Figure 20 is when the resistive film is applied. Plan view, 2nd
Fig. 1 is an enlarged sectional view of XXIXXI in Fig. 20, Fig. 22 is a plan view when each rod-shaped insulating material plate is broken, Fig. 23 is an enlarged sectional view of xxm-xxm in Fig. 22, and Fig. 2
Figure 4 is another cross-sectional view of Figure 23, and Figure 25 is a cross-sectional view of Figure 22.
It is an enlarged sectional view taken along xv-xxv. DESCRIPTION OF SYMBOLS 1... Insulating substrate, 3... Resistance film, 4... Electrode protrusion, 5... Electrode film, 5a... Top electrode film, 5b... Bottom electrode film. , 5C...side electrode film,
6...Rotor member, A...Insulating material plate, A1...
...rod-shaped insulating material plate, A6. A7...Shime groove.

Claims (1)

[Claims] (1). An insulating material plate in which a large number of insulating substrates are arranged vertically and horizontally is provided with grooves having a V-shaped cross section for breaking each insulating substrate on the upper and lower surfaces of the insulating material plate. A conductive paste for the upper electrode film and a conductive paste for the lower electrode film are respectively applied to the upper and lower surfaces of each insulating substrate in the insulating material plate, and then the insulating material plate is After breaking into rod-shaped insulating material plates along the rod-shaped insulating material, a conductive paste for the side electrode film connecting the upper electrode film and the lower electrode film is applied to the side surfaces of each insulating substrate in this rod-shaped insulating material. In the method for forming an electrode film, at least one of the conductive paste for the upper electrode film and the conductive paste for the lower electrode film is applied to two adjacent insulating substrates with the groove in between. A method for forming an electrode film in an electronic component, characterized in that the electrode film is applied in a divided manner at the grooves, without being applied continuously over both sides.