JPH1092601A - Terminal electrode for surface mount electronic parts and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a terminal electrode for surface mount electronic parts which has a high mechanical strength, is durable against high temperatures and hardly causes imperfect connection. SOLUTION: First electrodes 6 which are made of a glassed metal and directly connected to a resistor 3 are provided at both end sections of the surface of a substrate 2 made of an insulator and second electrodes 7 made of a glassed metal are provided at both end sections of the rear surface of the substrate 2 opposite to the first electrodes 6 in a state where the electrodes 7 are protruded from the rear surface. Then third electrodes 8 made of an Ag-resin material are provided at both end sections of the substrate 2 so that the electrodes 8 can be brought into contact with the electrodes 6 and 7 and can cover parts of the electrodes 7 from both ends of the substrate 2 with a prescribed thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal electrode of a surface mount type electronic component in which an electrode for surface mounting is formed at an end of an insulating substrate such as a chip resistor, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, for example, an electrode structure of a chip resistor for surface mounting is made of Ag-Pt using glass as a binder.
It was formed by applying and firing a so-called metal glaze paste containing such components. As disclosed in Japanese Patent Application Laid-Open No. 61-268001, this electrode manufacturing method divides a large substrate into strips, each electrode end face is exposed on a side face, and a number of chips are arranged in a line. Then, a conductive paint is applied to the end face, and thereafter, the chip is divided into individual chip components.

[0003]

In the case of the above prior art, electrodes on the end face are printed before being divided into individual chip components. Therefore, when divided into individual chips, there is a problem that cracks occur in the electrodes. Furthermore, since the electrodes are formed on the end faces before being divided individually, the electrodes are
It was printed only on the end face of the chip substrate, and had low mechanical strength.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has a high mechanical strength of an electrode, a high durability against high temperatures, and a terminal electrode of a surface mount type electronic component in which poor connection is unlikely to occur. It is intended to provide a manufacturing method.

[0005]

According to the present invention, a first electrode is provided at an end of a substrate surface of an insulator, and a second electrode is provided on the back surface of the substrate opposite to the first electrode with the substrate interposed therebetween. A third electrode that directly covers the end face and the two side surfaces of the substrate between the first and second electrodes and is in contact with the first and second electrodes; the third electrode is formed of a conductive paint; It is a terminal electrode of a surface mount electronic component in which a part of the electrode is covered with a predetermined thickness from the end face of the substrate.

The end face of the substrate is formed such that the second electrode and the third electrode protrude in a stepwise manner from the central portion of the back surface of the substrate toward the end face. Further, the first and second electrodes are formed of a metal glaze electrode material, the third electrode is formed of an Ag-resin conductive paint, and the first, second, and third electrodes exposed to the outside are formed. All are covered with Ni plating and solder plating.

According to the present invention, there is further provided a large-sized substrate made of an insulator in which a large number of dividing grooves are formed vertically and horizontally on the front and back sides of each chip portion. A first electrode is formed, a second electrode is formed on the back surface of the substrate opposite to the first electrode, and the substrate is divided into individual chip portions along the division grooves;
The divided substrate directly covers three surfaces between the first and second electrodes and contacts the first and second electrodes, and
A third covering a part of the electrode with a predetermined thickness from the end face of the substrate;
This is a method for manufacturing a terminal electrode of a surface mount electronic component that forms an electrode.

[0008]

According to the present invention, there is provided a terminal electrode for a surface-mounted electronic component and a method of manufacturing the same, wherein a third electrode is formed by printing on three sides of a substrate end, and five surfaces of the terminal electrode are formed as electrodes. In addition, the strength of the third electrode is high, and poor connection hardly occurs.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the terminal electrodes of the surface-mounted electronic component of this embodiment are also those of a chip resistor 1, and a convex resistor 3 is provided on the surface of a ceramic substrate 2.
Are formed by printing, and electrodes 4 are provided at both ends.
The resistor 3 is provided with ruthenium oxide to a thickness of about 10 μ,
A trimming groove 5 is formed upward from the bottom of the convex shape by laser or sand blast, and the resistance value is trimmed.

The electrode 4 of the chip resistor 1 is connected to the resistor 3
A first electrode 6 having both ends directly connected to each other,
A second electrode 7 is formed so as to protrude from the back surface side of the substrate 2 so as to face the electrode 6 with the substrate 2 interposed therebetween. The first and second electrodes 6 and 7 are made of Ag-Pd, Ag-Pt. Etc. are formed by printing a metal glaze paste. In addition, the first,
End surface 2a and side surface 2b of substrate 2 between second electrodes 6 and 7
Third, a paste of an Ag-resin-based conductive paint in which Ag is mixed into xylene or epoxyphenol resin is used.
An electrode 8 is provided. The third electrode 8 is provided so as to partially cover the first and second electrodes 6 and 7 from the end face side of the substrate 2 with a predetermined thickness, thereby achieving conduction between the two. Thus, the second electrode 7 and the third electrode 8 are formed so as to protrude in a stepwise manner from the central portion of the back surface of the substrate 2 toward the end surface.

Then, the first, second,
Ni plating 9 and solder plating 10 are sequentially applied to cover the entire third electrodes 6, 7 and 8, and the shape of the electrode 4 on the back surface side of the substrate 2 after the solder plating 10 is applied also changes to the back surface of the substrate 2. Is formed so as to protrude stepwise from the central portion side toward the end surface side. The surface of the resistor 3 is protected by a glass coat 11 and a resin coat 12.

Next, a method for manufacturing a terminal electrode of a surface-mounted electronic component of this embodiment will be described with reference to FIGS. First, as shown in FIG. 3A, a plurality of rows of metal glaze pastes serving as the first electrodes 6 are arranged at predetermined intervals across slits 14 which are division grooves of a ceramic plate 13 which is a large substrate to be divided. Print, 900 ° C
Fire at close temperature. Further, similarly, the second electrode 7
It is formed on the back surface of the ceramic plate 13 at a position facing the first electrode 6. Next, as shown in FIG. 3B, a large number of resistors 3 are printed and formed in a matrix on the ceramic plate 13 between the first electrodes 6, and fired at a temperature of 850 ° C. on average.
Then, as shown in FIG. 3C, a glass coat 11 is applied to the surface of the resistor 3 and fired at a temperature of 650 ° C. on average.
Thereafter, the ceramic plate 13 is divided individually along slits 14 provided vertically and horizontally for each chip resistor 1, and as shown in FIG. A third electrode 8 of a conductive paint is applied to a thickness of about 20 μ,
It is cured at a temperature of about 200 ° C. And FIG. 3 (E),
As shown in (F), Ni plating 9 and solder plating 10
Are sequentially applied to cover the first, second, and third electrodes 6, 7, and 8 exposed to the outside.

Finally, the resistor 3 of each chip resistor is trimmed to adjust the resistance value. Also, a resin coat 12 such as an epoxy resin is applied to the surface of the resistor 3 and cured at a temperature of about 200 ° C.

In some cases, the trimming is performed in the state shown in FIG. 3C.
To perform the steps shown in FIG. As a result, the trimming operation can be performed efficiently because the resistance value is trimmed without separating the ceramic plate 13 for each chip, and the resin coat 12 has an adverse effect on the resistor even during the subsequent plating operation. Nor.

According to the terminal electrodes of the surface-mount type electronic component of this embodiment, after being divided into individual chip resistors 1, A
Since the g-resin-based third electrode 8 is formed by printing, the third electrode 8 is formed by printing on the surfaces of the first and second electrodes 7 and 8, the substrate end surface 2a and the side surface 2b. Terminal electrode 5
The surface is formed as an electrode 4. Therefore,
The third electrode 8 covers the end of the substrate in a cap shape, has high mechanical strength, hardly causes cracks, and hardly causes poor connection. In particular, by forming the third electrode 8 using a conductive paint of an epoxy phenol resin, it is possible to make the third electrode 8 more durable. Although the divided substrate end surface stands on a rough surface, by covering this rough surface with the third electrode 8 made of a conductive paint, the third electrode is securely attached to the substrate end surface, and the end surface electrode is more mechanically mounted. Electrical and electrical reliability.

Further, the second electrode 7 functions as an independent land between the second electrode 7 and the circuit board during soldering, and the solder penetrates between the second electrode 7 and the circuit board due to surface tension during soldering. However, the soldering area is limited, the insulating effect is high, and the fixing force to the circuit board is extremely strong. Further, since the solder is sucked below the second electrode 7, the distance between the electrodes can be reduced, and the terminal electrodes of the surface mount type electronic component can be miniaturized and the circuit board can be mounted at a high density. is there. Further, it is possible to pass a circuit pattern through the surface of the circuit board between the second electrodes 7, and the effect of preventing the unnecessary spread of the solder is extremely great in improving the mounting density.

Also, since the back surface of the chip resistor protrudes stepwise and is soldered to the substrate at its tip,
The positioning is accurately performed, and the measurement of the resistance value and the like can be reliably performed. Furthermore, since the first and second electrodes 6, 7 exposed to the third electrode 8 and the surface are covered with the Ni plating 9 and the solder plating 10, there is no migration of silver atoms and good solderability. It is.

Incidentally, the resistor of the chip resistor according to the present invention comprises:
A metal film resistor, a carbon film resistor, and the like can be appropriately selected according to the application. In addition, the components of the metal glaze paste and the Ag-resin-based conductive paste may contain other additives as appropriate, and are not limited to those of this embodiment.

[0019]

According to the terminal electrode of the surface-mounted electronic component and the method of manufacturing the same according to the present invention, the three surfaces of the terminal electrode of the surface-mounted electronic component are covered with the third electrode, and the strength of the third electrode is increased, and the crack is increased. And the like are prevented, and the electrical reliability is increased. Further, by forming the second electrode and the third electrode in a stepped shape, the soldering area is reliably limited, and the fixing force to the circuit board is extremely strong.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a terminal electrode of a surface mount electronic component of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIGS. 3A, 3B, 3C, 3D, 3E, and 3F are longitudinal sectional views showing steps of manufacturing a terminal electrode of the surface-mounted electronic component of this embodiment.

[Explanation of symbols]

 Reference Signs List 1 chip resistor 2 substrate 2a end surface 2b side surface 3 resistor 4 electrode 6 first electrode 7 second electrode 8 third electrode 9 Ni plating 10 solder plating

Continued on the front page (72) Inventor Yozo Ohara 3158 Shimookubo, Osawano-cho, Kamishinkawa-gun, Toyama Prefecture Hokuriku Electric Industry Co., Ltd.

Claims (8)

[Claims] An electrode is provided on a back surface of a substrate of an insulator, and an electrode made of a conductive paint that covers an end surface of the substrate and is in contact with a part of an end surface side of the electrode is provided. A terminal electrode of a surface-mounted electronic component in which a part of the end face of the substrate is covered with a predetermined thickness. 2. A first electrode is provided at an end of the substrate surface of the insulator, and a second electrode is provided on the back surface of the substrate opposite to the first electrode with the substrate interposed therebetween. A third electrode that directly covers the end face of the substrate between the two electrodes and the two side surfaces on both sides thereof is provided in contact with the first and second electrodes, and the third electrode is formed of a conductive paint, and is part of the second electrode. 2. The terminal electrode of a surface-mounted electronic component according to claim 1, wherein the terminal electrode is covered with a predetermined thickness from the end face of the substrate. 3. The surface mounting according to claim 1, wherein each of the electrodes is formed on the end face of the substrate so as to protrude from the central portion of the back surface of the substrate toward the end face in a stepwise manner toward the back surface. Terminal electrodes for electronic components. 4. The back electrode is formed of a metal glaze electrode material, and the conductive paint is formed of an Ag-resin conductive paint.
A terminal electrode of the surface-mounted electronic component described. 5. The Ag-resin-based conductive resin paint,
5. The terminal electrode for a surface-mounted electronic component according to claim 4, wherein the terminal electrode is an epoxyphenol-based resin. 6. A large-sized substrate of an insulator having a large number of divided grooves formed vertically and horizontally on both sides thereof for dividing each chip portion,
An electrode is formed on the back surface of the substrate of the insulating substrate, the substrate is divided along the dividing groove, a conductive paint is applied to an end surface of the divided substrate, and an end surface electrode in contact with a part of the electrode is formed. A method for manufacturing a terminal electrode of a surface-mounted electronic component to be formed. 7. A first electrode is formed on each of both ends of each chip portion on the surface of the insulating substrate, and a second electrode is formed on the back surface of the substrate opposite to the first electrode with the substrate interposed therebetween. And dividing the substrate into individual chip portions along the division grooves,
The divided substrate directly covers the three surfaces between the first and second electrodes, contacts the first and second electrodes, and partially covers the second electrode with a predetermined thickness from the end face of the substrate. The method for manufacturing a terminal electrode of a surface-mounted electronic component according to claim 7, wherein a covering third electrode is formed. 8. The conductive electrode is printed directly on the end face of the substrate, and at the time of printing, a conductive paint is also applied to a part of the electrode, and plating is performed on the entire surface of each electrode. 8. The method for manufacturing a terminal electrode of a surface-mounted electronic component according to 6 or 7.