JP2939425B2 - Surface mount type resistor and its manufacturing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface mount type resistor having a surface mount electrode formed at an end of an insulating substrate, such as a chip resistor, and its manufacture. About the method. 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 above-described conventional technique, electrodes on the end face are printed before being divided into individual chip parts. Therefore, when divided into individual chips, there is a problem that cracks occur in the electrodes. Further, the electrode made of a conductive paint printed on the end face of the chip substrate has a low bonding strength with solder and a low mechanical strength when soldering the chip component to the circuit board. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has an object to provide a surface mount type resistor which has high mechanical strength of electrodes, has high durability against high temperatures, and hardly causes poor connection, and a method of manufacturing the same. The purpose is to provide. According to the present invention, a metal glaze-based first electrode is provided at an end of an insulating substrate surface, and the first electrode is provided on a substrate opposite to the first electrode. A metal glaze-based second electrode is also provided on the back surface, and a resistor is provided between the first electrodes.
An antibody is formed, and a glass coat and a resin
The first and second electrodes are further laminated on a part near the end side and the end face of the substrate between the first and second electrodes.
An electrode is provided, and the third electrode is a surface-mounted resistor formed of a conductive paint, and the first, second, and third electrodes are covered with plating. Further, the second electrode and the third electrode are formed so as to protrude in a stepwise manner from the center to the end face of the back surface of the substrate. further,
The plating is Ni plating and solder plating, and the third electrode protruding from the second electrode surface and the second electrode surface is used.
This plating is applied to the entire electrode. According to the present invention, there is further provided a large-sized insulating substrate having a large number of vertical and horizontal dividing grooves for dividing each chip portion, and an end portion of each chip portion on the surface of the insulating substrate.
A metal glaze-based first electrode is formed, and a metal glaze-based second electrode is formed on the back surface of the substrate opposite to the first electrode with the substrate interposed therebetween. The second electrode is divided into individual chip portions, and covers an end surface between the first and second electrodes formed on the front and back of the divided substrate and partially covers an end portion of the first and second electrodes. A surface mount type resistor for forming a third electrode covering a part of the end side of the substrate with a predetermined thickness from the substrate end surface side with a conductive paint, and plating the first, second electrodes and the third electrode surface. It is a manufacturing method of the container. Further, the third electrode is directly printed on the end face of the substrate, and at the time of this printing, a conductive paint is applied to a part of the end face side of the first and second electrodes and the side face of the substrate between the first and second electrodes. Is done. Then, Ni plating and solder plating are applied to the entire surfaces of the first, second and third electrodes exposed to the outside. According to the surface mount type resistor and the method of manufacturing the same of the present invention, a third electrode of a conductive paint is formed by printing on the end of the substrate.
Since a part of the first and second electrodes on the front and back surfaces is covered, and portions of the first and second electrodes on the front and back surfaces where the third electrode is not applied are plated, the soldering strength when attached to the circuit board is provided. Will be higher. Furthermore, the first and second electrodes on the front and back surfaces are connected by a conductive paint, so that cracks and the like are less likely to occur, and reliable conduction can be achieved. An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the surface mount type resistor of this embodiment is also for a chip resistor 1, and a convex resistor 3 is printed and formed on the surface of a ceramic substrate 2, and electrodes 4 are provided at both ends. Is provided. The resistor 3 is
Ruthenium oxide is provided with a thickness of about 10 μm, and a trimming groove 5 is formed upward from the bottom of the convex shape by laser or sandblast to trim the resistance value. 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 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 of manufacturing the surface mount type resistor according to 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 and bake at a temperature near 900 ° C. Further, similarly, the second electrode 7 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. And FIG.
As shown in (C), a glass coat 1 is formed on the surface of the resistor 3.
And firing at an average temperature of 650 ° C. 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 and cured at a temperature of about 200 ° C. Then, as shown in FIGS. 3E and 3F, 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 surface mount resistor of this embodiment,
After being divided into the individual chip resistors 1, the Ag-resin-based third electrode 8 is formed by printing, so that the surface of the first and second electrodes 6, 7 and the five surfaces of the substrate end surface 2a and the side surface 2b are provided. Then, a third electrode 8 is formed by printing, and five surfaces of the terminal electrodes are formed as the electrodes 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, since the Ni plating 9 and the solder plating 10 are applied to the exposed surfaces of the first and second electrodes 6 and 7, the mechanical strength when soldering to the circuit board is high. This is because the bonding strength of the metal plating paste to the first and second electrodes 6 and 7 is higher than the bonding strength of the Ni plating 9 and the solder plating 10 to the conductive paint. 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, the solder penetrates into the gap between the second electrode 7 and the circuit board, and the bonding strength is high as described above. It is. Also,
Since the solder is sucked below the second electrode 7, the distance between the electrodes can be reduced, and the size of the surface mount type resistor can be reduced and the circuit board can be mounted at a high density.
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 third electrode 8 and the first and second electrodes 6, 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 the solderability is good. 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. 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. According to the surface mount type resistor and the method of manufacturing the same of the present invention, the end face of the surface mount type resistor is formed of a conductive paint, and the portion to be soldered to the circuit board is made of metal. Since the glaze electrode is plated and formed,
Cracks and the like are prevented from occurring, soldering strength to the circuit board is increased, and electrical reliability is enhanced. 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. In addition, the resistance
Cover the body surface in the order of glass coat and resin coat
Ensures that surface insulation and protection are
A highly mountable surface mount type resistor can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing one embodiment of a surface mount resistor according to 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 the surface-mounted resistor of this embodiment. [Description of Signs] 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

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Mitsuru Yokoyama               3158 Shimo-Okubo, Osawano-cho, Kamishinkawa-gun, Toyama               Hokuriku Electric Industry Co., Ltd. (72) Inventor Yozo Ohara               3158 Shimo-Okubo, Osawano-cho, Kamishinkawa-gun, Toyama               Hokuriku Electric Industry Co., Ltd.                (56) References JP-A-57-184202 (JP, A)                 JP-A-61-210601 (JP, A)                 JP-A-61-268001 (JP, A)                 JP-A-58-30118 (JP, A)                 Shokai Sho 57-119501 (JP, U)

Claims (1)

(57) [Claims] A pair of metal glaze on the edge of the insulator substrate surface
A metal glaze-based second electrode is also provided on the back surface of the substrate opposite to the first electrode with the substrate interposed therebetween, and a resistor is formed between the first electrodes. surface
A glass coat and a resin coat are laminated on
A third electrode made of a conductive paint applied to the end face of the substrate between the first and second electrodes is provided so as to be connected to a part near the end of the two electrodes, and the first, second and third electrodes are provided. There are surface-mounted resistors that are covered with plating. 2. 2. The surface mount type resistor according to claim 1, wherein the second electrode and the third electrode are formed so as to protrude toward the rear surface side in a stepwise manner from the center portion side to the end surface side of the substrate rear surface. 3. 3. The surface mount type resistor according to claim 2, wherein the plating is Ni plating and solder plating, and the plating is applied to the entire surface of the second electrode and the third electrode protruding from the surface of the second electrode. 4. A large substrate of an insulator having a large number of vertical and horizontal dividing grooves for dividing each chip portion is provided, and a first metal glaze type is provided at both ends of each chip portion on the surface of the insulating substrate.
An electrode is formed, a metal glaze-based second electrode is formed on the back surface of the substrate opposite to the first electrode, and a resistor is formed between the first electrodes. Body surface
The surface is coated with glass , divided into individual chip portions along the division grooves, and covers the end faces between the first and second electrodes formed on the front and back of the divided substrate, while covering the first and the first electrodes.
Forming a third electrode, which covers a part of the end of the second electrode and a part of the end of the second electrode from the end face of the substrate with a predetermined thickness, using a conductive paint; The electrode and the third
Plating on electrode surface, resin coating on resistor surface
A method of manufacturing a surface mount type resistor. 5. The third electrode is directly printed on the end face of the substrate, and at the time of printing, a conductive paint is also applied to a part of the end face side of the first and second electrodes and the side face of the substrate between the first and second electrodes. A method for manufacturing the surface-mounted resistor according to claim 4. 6. Ni is coated on the entire surface of the first, second and third electrodes exposed to the outside.
6. The method for manufacturing a surface mount resistor according to claim 4, wherein plating and solder plating are sequentially performed.