JPH07211504A - Terminal electrode for surface-mounting type electronic parts and its production - Google Patents

Abstract

PURPOSE:To provide an electrode with a large mechanical strength and durabil ity against high temperature in which connection failure is hardly generated. CONSTITUTION:A first electrode is provided on the end part of the surface of an insulator substrate 2 and a second electrode is provide< on the back surface of the substrate 2 with the substrate 2 in between, being opposed to the first electrode. End face 2a and side face 2b of the substrate 2 between the first and second electrodes are covered directly, thereby forming a third electrode in contact with the first and second electrodes. The third electrode is formed of conductive paint, and the second electrode is partly covered with a specified thickness from the end face 2a side of the substrate 2.

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 such as a chip resistor having a surface mount electrode formed on an end of an insulating substrate and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, for example, the electrode structure of a surface mounting chip resistor uses Ag-Pt as a binder.
It was formed by applying a so-called metal glaze paste containing the above components as a component and firing it. In this electrode manufacturing method, as disclosed in Japanese Patent Laid-Open No. 61-268001, a large substrate is divided into strips, each electrode end face is exposed on a side surface, and a large number of chips are arranged in a line. The chip was divided into individual parts, the end face of which was coated with a conductive paint, and then divided into individual chip parts.

[0003]

In the case of the above-mentioned conventional technique, the electrodes on the end faces are printed before dividing into individual chip parts. Therefore, there is a problem that cracks may occur in the electrodes when divided into individual chips. Furthermore, since the electrodes are formed on the end faces before the individual division, the electrodes are
It was printed only on the end face of the chip substrate and had a weak mechanical strength.

The present invention has been made in view of the above-mentioned problems of the prior art, and has a high mechanical strength of the electrode, durability against high temperature, and a terminal electrode of a surface mount type electronic component in which poor connection is unlikely to occur, and the same. It is intended to provide a manufacturing method.

[0005]

According to the present invention, a first electrode is provided on an end portion 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. And a third electrode that directly covers the substrate end surface and the two side surfaces 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, and the second electrode is formed. 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 side of the substrate.

The substrate end surface is formed by projecting the second electrode and the third electrode stepwise from the central portion side of the back surface of the substrate toward the end surface side. Furthermore, the first and second electrodes are formed of a metal glaze-based electrode material, the third electrode is formed of Ag-resin-based conductive paint, and the first, second, and third electrodes exposed to the outside are formed. All are covered with Ni plating and solder plating.

Further, according to the present invention, a large substrate of an insulator in which a large number of dividing grooves for dividing each chip portion are formed vertically and horizontally is provided, and the first substrate is provided at both ends of each chip portion on the surface of the insulating substrate. An electrode is formed on each side, and a second electrode is formed on the backside of the substrate opposite to the first electrode, and the substrate is divided into individual chip parts along the dividing grooves. A third surface that directly covers the three surfaces of the substrate between the first and second electrodes and is in contact with the first and second electrodes and covers a part of the second electrode from the substrate end surface side with a predetermined thickness. It is a manufacturing method of a terminal electrode of a surface mount electronic component for forming an electrode.

[0008]

In the terminal electrode of the surface mount type electronic component and the method of manufacturing the same according to the present invention, the third electrode is formed by printing on three sides of the substrate end, and the five surfaces of the terminal electrode are formed as electrodes. The strength of the third electrode is high, and poor connection is unlikely to occur.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the terminal electrode of the surface mount type electronic component of this embodiment is also for the chip resistor 1, and the convex resistor 3 is provided on the surface of the ceramic substrate 2.
Are formed by printing, and electrodes 4 are provided on both ends thereof.
The resistor 3 is provided with ruthenium oxide in a thickness of about 10 μ,
A trimming groove 5 is formed upward from the bottom of the convex shape by laser or sandblasting to trim the resistance value.

The electrode 4 of the chip resistor 1 is a resistor 3
The first electrode 6 whose both ends are directly connected to each other, and
The second electrode 7 is formed so as to face the electrode 6 and the substrate 2 and to project to the back surface side of the substrate 2. The first and second electrodes 6 and 7 are Ag-Pd and Ag-Pt. It is formed by printing a metal glaze paste such as. In addition, the first,
The end surface 2a and the side surface 2b of the substrate 2 between the second electrodes 6 and 7
And a paste of Ag-resin-based conductive paint, in which xylene or epoxyphenol resin is mixed with Ag.
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, and achieves electrical continuity between them. As a result, the second electrode 7 and the third electrode 8 are formed so as to project in a stepwise manner from the central portion side of the back surface of the substrate 2 toward the end surface side.

The first, second, and
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 is also the back surface of the substrate 2. Is formed so as to project in a stepwise manner from the central portion side toward the end face side. The surface of the resistor 3 is protected by a glass coat 11 and a resin coat 12.

Next, a method of manufacturing the terminal electrodes of the surface mount type electronic component of this embodiment will be described with reference to FIGS. 3 (A) to 3 (F). First, as shown in FIG. 3 (A), a plurality of rows of metal glaze paste to be the first electrodes 6 are arranged at predetermined intervals with a slit 14 which is a dividing groove of a ceramic plate 13 which is a large substrate to be divided. Print, 900 ° C
Bake at near temperature. Similarly, the second electrode 7 also
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. 3 (B), 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, the surface of the resistor 3 is coated with the glass coat 11 and fired at a temperature of 650 ° C. on average.
After that, the ceramic plate 13 is individually divided along the slits 14 vertically and horizontally provided for each chip resistor 1, and as shown in FIG. Apply the third electrode 8 of conductive paint to a thickness of about 20μ,
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. Further, a resin coat 12 such as an epoxy resin is applied to the surface of the resistor 3 and cured at a temperature near 200 ° C.

The trimming may be performed in the state shown in FIG. 3C. In this case, the resin coat 12 is then used.
Then, the steps following FIG. 3D are performed. As a result, the resistance value is trimmed without separating the ceramic plate 13 into chips, so that the trimming work can be performed efficiently, and the resin coat 12 adversely affects the resistor during the subsequent plating work. Nor.

According to the terminal electrode of the surface mount type electronic component of this embodiment, after dividing into the individual chip resistors 1,
Since the third electrode 8 of the g-resin system is formed by printing, the third electrode 8 is formed by printing on the surfaces of the first and second electrodes 7, 8, the substrate end surface 2a and the side surface 2b. Terminal electrode 5
The surface is formed as the electrode 4. Therefore,
The third electrode 8 covers the end portion of the substrate like a cap, has high mechanical strength, is less prone to cracks, and is less likely to cause poor connection. In particular, by forming the third electrode 8 using a conductive coating material of epoxyphenol resin, it is possible to make it more durable. Further, the divided substrate end surface stands on a rough surface, but by covering this rough surface with the third electrode 8 of conductive paint, the third electrode surely adheres to the substrate end surface, and the end surface electrode is more mechanically attached. The electrical and electrical reliability is high.

Further, the second electrode 7 functions as an independent land with 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 insulation effect is high, and the adhesion to the circuit board is extremely strong. In addition, since the solder is sucked below the second electrode 7, the distance between the electrodes can be shortened, and the size of the terminal electrode of the surface mount electronic component and the high density mounting of the circuit board can be achieved. is there. Furthermore, it is also possible to pass a circuit pattern on the surface of the circuit board between the second electrodes 7, and the effect of improving the mounting density by preventing unnecessary spread of the solder is extremely large.

Since the back surface of the chip resistor projects in a stepwise manner and is soldered to the substrate at its tip,
The positioning is accurately performed, and the resistance value can be surely measured. Furthermore, since the third electrode 8 and the first and second electrodes 6 and 7 exposed on the surface are covered with the Ni plating 9 and the solder plating 10, there is no migration of silver atoms and solderability is also good. Is.

The resistor of the chip resistor of the present invention is
A metal film resistor, a carbon film resistor, or the like can be appropriately selected according to its use. Further, the components of the metal glaze paste and the Ag-resin-based conductive paste may appropriately contain other additives, and are not limited to those of this embodiment.

[0019]

As described above, the terminal electrode of the surface mount type electronic component and the method for manufacturing the same according to the present invention cover the five surfaces of the terminal electrode of the surface mount type electronic component with the third electrode to enhance the strength of the third electrode and to prevent cracks. Etc. are prevented and the electrical reliability is high. Furthermore, by forming the second electrode and the third electrode in a stepwise manner, the soldering area is surely limited, and the adhesion force to the circuit board is extremely strong.

[Brief description of drawings]

FIG. 1 is a plan view showing an 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.

3 (A), (B), (C), (D), (E), and (F) are vertical cross-sectional views showing the manufacturing process of the terminal electrode of the surface-mounted electronic component of this embodiment.

[Explanation of symbols]

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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yozo Ohara 3158 Shimookubo, Osawano-cho, Kamishinagawa-gun, Toyama Prefecture Hokuriku Electric Industry Co., Ltd.

Claims (7)

[Claims] 1. A first electrode is provided on an end portion of a surface of a substrate of an insulator, and a second electrode is provided on a back surface of the substrate opposite to the first electrode with the substrate interposed therebetween. A third electrode is provided which directly covers the substrate end face and the two side faces between the electrodes and is in contact with the first and second electrodes. The third electrode is formed of a conductive paint and a part of the second electrode is formed on the substrate end face. Terminal electrodes for surface-mounted electronic components that are covered with a specified thickness from the side. 2. The surface mounting according to claim 1, wherein the end face of the substrate is formed by projecting the second electrode and the third electrode stepwise from the central portion side of the back face of the substrate toward the end face side. Type electronic component terminal electrode. 3. The surface mount type electron according to claim 1, wherein the first and second electrodes are formed of a metal glaze-based electrode material, and the third electrode is formed of an Ag-resin-based conductive paint. Terminal electrodes of parts. 4. The Ag-resin-based conductive resin coating material,
The terminal electrode of the surface mount electronic component according to claim 3, which is an epoxyphenol resin. 5. A large-sized substrate made of an insulating material, in which a large number of dividing grooves are formed vertically and horizontally for dividing each chip portion, is provided, and a first electrode is provided at an end portion of each chip portion on the surface of the insulating substrate. A second electrode is also formed on the back surface of the substrate opposite to the first electrode with the substrate sandwiched, and the substrate is divided into individual chip parts along the dividing grooves, and the divided substrate is formed. Forming a third electrode that directly covers the three surfaces between the first and second electrodes and is in contact with the first and second electrodes, and covers a part of the second electrode from the substrate end surface side with a predetermined thickness. A method of manufacturing a terminal electrode of a surface mount electronic component. 6. The third electrode is directly printed on the end surface of the substrate, and at the time of printing, a conductive paint is applied to a part of the first and second electrodes and the side surface of the substrate between the first and second electrodes. The method for manufacturing a terminal electrode of a surface-mounted electronic component according to claim 5. 7. The method of manufacturing a terminal electrode of a surface-mounted electronic component according to claim 6, wherein all of the first, second and third electrodes exposed to the outside are covered with Ni plating and solder plating.