JP3167968B2 - Manufacturing method of chip resistor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a chip resistor in which an electrode for surface mounting is formed at an end of an insulating substrate. Conventionally, an electrode structure of a chip resistor for surface mounting is formed by applying and firing a so-called metal glaze paste containing Ag-Pt or the like as a component using glass as a binder. there were. As disclosed in Japanese Patent Application Laid-Open No. 61-268001,
The large substrate is divided into strips, the end faces of each electrode are exposed on the side, a large number of chips are divided in a line, and a conductive paint is applied to the end faces. It was split. [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. 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. [0004] The present invention has been made in view of the above-mentioned conventional problems, and enables accurate division easily, high mechanical strength of electrodes, durability against high temperatures, and hardly causes poor connection. An object of the present invention is to provide a method for manufacturing a chip resistor. According to the present invention, a large number of dividing grooves for dividing a large-sized insulating substrate for each chip portion are provided.
Formed on the front and back of a large-sized substrate, a plurality of rows of first electrodes are printed at predetermined intervals across the above-mentioned dividing groove, and a first electrode is provided in a portion to be each chip substrate. Insert the above-mentioned dividing groove on the other side of the substrate,
An electrode is provided, and a resistor is printed and formed between the first electrodes.
After applying a glass coat on the surface of each
To adjust the resistance, apply a resin coat,
Divide the large substrate along the dividing grooves on the front and back,
Then, the first and second electrodes cover the end face of the substrate between the first and second electrodes.
Forming a third electrode in contact with the two electrodes with a conductive paint,
Further , the present invention relates to a method of manufacturing a chip resistor in which plating is performed on the entire surface of each electrode . Further, the first and second electrodes are made of metal
Of the third electrode, which is formed of a
The paint is formed of an Ag-resin-based material. Up
The Ag-resin-based conductive resin paint is epoxy phenol.
Resin . The method of manufacturing a chip resistor according to the present invention comprises the steps of:
Individual chips along the dividing slits formed on the surface
The substrate is formed, and the third electrode is printed on the edge of the divided substrate
Formed and provided with terminal electrodes.
The strength of the electrode is high, and connection failure is unlikely to occur . An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the chip resistor of this embodiment is also for the chip resistor 1, and a convex resistor 3 is formed by printing on the surface of a ceramic substrate 2.
Electrodes 4 are provided at both ends. The resistor 3 is provided with ruthenium oxide in a thickness of about 10 μm, and a trimming groove 5 is formed upward from the bottom of the convex shape by laser or sand blast, so that 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 of manufacturing the chip resistor according to this embodiment will be described with reference to FIGS. First, as shown in FIG. 3A, a slit 1 which is a dividing groove of a ceramic plate 13 which is a large substrate to be divided.
A plurality of rows of a metal glaze paste to be the first electrode 6 are printed at predetermined intervals with 4 interposed therebetween and fired at a temperature close to 900 ° C. Further, similarly, the second electrode 7 is also connected to the ceramic plate 1.
3 is formed on the back surface 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. The trimming may be performed in the state shown in FIG. 3 (C).
To perform the steps shown in FIG. Thereby, the resistance value is trimmed without separating the ceramic plate 13 for each chip, so that the trimming operation can be performed efficiently, and the resin coat 12 adversely affects the resistor even during the subsequent plating operation. Nor. According to the chip resistor of this embodiment, since the Ag-resin-based third electrode 8 is formed by printing after division, the surfaces of the first and second electrodes 7, 8 and the substrate end face 2a are formed.
The one in which the third electrode 8 is formed by printing, is formed as an electrode 4. Therefore, the third electrode 8 covers the edge of the substrate, 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 circuit board 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 chip resistor can be reduced in size and the circuit board can be mounted at a high density. Further, a circuit pattern can be passed through 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. Also, since the back surface of the chip resistor protrudes stepwise and is soldered to the substrate at the 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. The resistor of the present invention can be appropriately selected according to the application, such as a metal film resistor and a carbon film resistor. The above metal glaze paste, Ag
-The components of the resin-based conductive paste may optionally contain other additives, and are not limited to those of this embodiment. The manufacturing method of the chip resistor of the present invention is as follows.
Divide the board by dividing grooves formed on both sides of the board.
The end surface of the divided chip resistor is conductively coated.
By covering the material with the third electrode, the strength of the third electrode is increased, cracks and the like are prevented, and the electrical reliability is increased. Further, 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 chip resistor 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 the chip resistor of the 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 Japanese Utility Model Showa 57-119501 (JP, U)                 Actual opening 56-110674 (JP, U)                 Shokai 61-102001 (JP, U)

Claims (1)

(57) [Claims] Forming a large number of division grooves for dividing the large substrate of the insulator for each chip portion on the front and back of the large substrate, printing the first electrode in a plurality of rows at predetermined intervals across the division grooves,
A first electrode provided on the portion serving as the chip substrate, the second electrode is provided sandwiching the dividing grooves in the rear surface of the opposite side of the substrate and the first electrode, between the first electrode Resistor
After printing and applying a glass coat on the surface,
Trim the antibody, adjust the resistance, and add resin
And place the large board along the dividing grooves on the front and back.
And thereafter, the end face of the substrate between the first and second electrodes is divided.
Cover the third electrode in contact with the first and second electrodes with a conductive paint
And then plating the entire surface of each electrode.
Method of manufacturing a chip resistor, characterized in that to. 2. The first and second electrodes are made of metal glaze-based electrode material.
And the conductive paint for the third electrode is an Ag-resist.
Claim
Item 2. A method for manufacturing a chip resistor according to Item 1 . 3. The Ag-resin-based conductive resin paint is an epoxy resin.
3. The chip resistor according to claim 2, which is an enol resin.
Construction method .