JPH07201539A - Manufacture of square type chip resistor - Google Patents

Abstract

PURPOSE:To increase a resistive film in exposed area so as to enhance the resistive film and a conductor in connectability between them by a method wherein the belt-like resistive film is continuously formed in a groove cut in a first insulating board, and a laminated insulating body pinched between the first and the second insulating board is cut off as aligned with the groove. CONSTITUTION:Grooves 4 are provided onto an insulating board 2 in parallel at a certain interval, and belt-like resistive film layers 5 are formed in parallel with each other at a certain interval on the surface of the insulating board 2 where the grooves 4 are provided making nearly right angles with the grooves 4. Then, an insulating board 3 is made to overlap the surface of the insulating board 2 where the resistive film layers 5 are provided, whereby the resistive film layers 5 are sandwiched between the insulating boards 2 and 3 for the formation of a laminated insulator 9. The resistive film layers 5 are cut off along their lengthwise direction into strips of insulator making the laminated insulator 9 aligned with the grooves 4, and conductive parts 6 are formed on both the side faces of the insulator strip where the resistive film is exposed, and the insulator strip provided with the conductive parts 6 is cut at an intermediate point between the resistive films and split into chips.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a rectangular chip resistor mounted on a cross portion of a printed wiring board, for example.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a rectangular chip resistor of this type, a configuration disclosed in, for example, Japanese Patent Laid-Open No. 5-205902 is known.

In the method of manufacturing a rectangular chip resistor disclosed in Japanese Patent Laid-Open No. 5-205902, a plurality of sets of ruthenium oxide resistance films are printed and dried on the surface of the first insulating plate. Then, a plurality of sets of internal electrodes are formed by printing so as to partially overlap both ends of each resistance film.

Further, the second insulating plate is bonded to the surface of the first insulating plate on which a plurality of sets of resistance films are formed by heating and pressurizing. Then, this laminated insulator is appropriately cut and calcined to form a plurality of semi-finished resistors each having a composite ceramic substrate provided with a resistance film and internal electrodes connected to both ends thereof.

Next, the semi-finished resistor is rounded at each ridge with a barrel grinder. Then, the semi-finished resistors are connected to internal electrodes at both ends thereof, and nickel plating layers and solder plating layers are sequentially formed to form external electrodes which are conductive portions, thereby forming a rectangular chip resistor.

[0006]

However, in the method of manufacturing a rectangular chip resistor described in Japanese Patent Laid-Open No. 5-205902, the area of the internal electrode connected to the resistance film exposed from the end face of the laminated insulator is Since it is small, there is a problem that the connection area with the nickel plating layer that will be the external electrode is small and the connection force is weak.

The present invention has been made in view of the above problems. The area of the resistance film exposed on the end face of the laminated insulator is increased, the stability of the adhesion between the resistance film and the conductive portion is improved, and the reliability is improved. The present invention provides a method for manufacturing a rectangular chip resistor having a high price.

[0008]

According to the method of manufacturing a rectangular chip resistor of the present invention, a plurality of grooves are formed substantially parallel to each other on a first insulating plate, and the first insulating plate is provided with a plurality of grooves. A plurality of strip-shaped resistive film layers are formed on the surface on which the grooves are formed so that the lengthwise direction is continuous in the grooves and is substantially perpendicular to the lengthwise direction of the grooves, and is substantially parallel to each other. Overlaying a second insulating plate on the surface of the first insulating plate on which the resistive film layer is formed,
The resistive film layer is sandwiched between the first and second insulating plates to form a laminated insulator, and the laminated insulator is aligned with the groove formed in the first insulating plate to form the resistive film layer. Is cut along the longitudinal direction to form an elongated insulating piece, and conductive portions are formed on both side surfaces of the elongated insulating piece where the resistance film is exposed, and the elongated insulating piece is formed from an intermediate position between the resistance films. Each is cut into chips.

[0009]

The method of manufacturing the rectangular chip resistor according to the present invention is the first method.
Since a resistive film is continuously formed in a strip shape in the groove formed in the insulating plate and the laminated insulator sandwiched between the first and second insulating plates is cut in conformity with the groove, The resistance film formed over the inner surface of the groove of the insulating plate is exposed, the exposed area of the resistance film is increased, and the connectivity between the resistance film and the conductive portion is improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A square chip resistor manufactured by the method for manufacturing a square chip resistor according to the present invention will be described below with reference to the drawings.

1 to 3, reference numeral 1 is a rectangular chip resistor, and the rectangular chip resistor 1 is a pair of first and second rectangular plates formed of an insulating ceramic material plate or a synthetic resin plate. The first and second insulating plates 2 and 3 are laminated and formed. Further, groove surfaces 4a inclined in a taper shape are formed at both edges of the first insulating plate 2 in the longitudinal direction facing the second insulating plate 3.

In the rectangular chip resistor 1, a strip-shaped resistance film 5 having a longitudinal direction along the longitudinal direction is sandwiched between the first and second insulating plates 2 and 3 at substantially the center. ing. The longitudinal end of the resistance film 5 is formed over the groove surface 4a.

Further, conductive portions 6 are formed on both ends of the rectangular chip resistor 1 in the longitudinal direction by nickel plating, solder plating, or the like so as to be in contact with the ends of the resistance film 5. Further, electrodes 7 are formed on both ends of the rectangular chip resistor 1 in the longitudinal direction by nickel plating or solder plating so as to cover the conductive portion 6.

Next, a process of manufacturing the above rectangular chip resistor will be described with reference to the drawings.

First, as shown in FIG. 4, the first insulating plate 2 is formed into a substantially rectangular flat plate with a substantially rectangular flat plate before firing. Then, the first insulating plate 2
As shown in FIG. 5, a plurality of linear grooves V 4 having a V-shape in the depth direction are formed substantially parallel to each other on the plane of the first insulating plate 2 on both sides of the first insulating plate 2. A groove surface 4a having substantially the same inclination as the grooves 4 and 4 is formed on the edge.

Then, on the plane where the groove 4 of the first insulating plate 2 is formed, as shown in FIG.
Strip-shaped resistance film 5, which is substantially perpendicular to the longitudinal direction of
5 are formed by printing in parallel with a plurality of strips at intervals in the width direction.

When the resistance films 5 and 5 are formed, the distance a between the resistance films 5 and 5 is approximately twice the distance b from the edge of the first insulating plate 2 to the edge of the resistance film 5 ( It is formed so that the distance is a = 2b).

As the material of the resistance film 5, when the first insulating plate 2 is a ceramic material plate, a resistive substance such as silver, palladium, gold or tungsten, molybdenum, ruthenium, tin is used as glass or resin. As the dispersed resistance paste, if the first insulating plate 2 is a synthetic resin plate, a synthetic resin resistance paint using a resistance substance such as silver or carbon is used.

The resistance film 5 is formed by using the resistance film 5 shown in FIGS.
As shown in FIG. 2, the resistance film 5 is formed by printing on the first insulating plate 2 so that the resistance film 5 is continuously formed also in the orthogonal portion in the groove 4.

Next, as shown in FIG. 7, the first insulating plate 2
The second insulating plate 3 made of the same material as the first insulating plate 2 and having the same flat plate shape is laid on the flat surface on which the groove 4 and the resistance film 5 are formed and heated at 150 ° C. to 200 ° C. for laminated insulation. Form body 9. When the first and second insulating plates 2 and 3 are synthetic resin plates, they are bonded with an adhesive material.

Then, as shown in FIG. 7, the laminated insulator 9 is cut in a direction corresponding to the groove 4 formed in the first insulating plate 2 in a direction in which the longitudinal direction of the strip-shaped resistance film 5 is cut. An elongated insulating piece 10 is formed. Further, as shown in FIG. 8, a V-shaped split groove is formed on the upper surface of the second insulating plate 3 of the elongated insulating piece 10 along the direction in which the resistive films 5 are divided into substantially central positions.
Forming 11.

After that, the elongated insulating piece 10 is fired. In addition,
The firing temperature is 800 ° C. or higher when the material of the resistance film 5 is a thick film resistance paste such as silver, palladium, gold or ruthenium.
The first and second insulating plates 2 and 3 are sintered by firing at 900 ° C. When the material of the resistance film 5 is tungsten or molybdenum, it is 1400 ° C. to 1 in a N ₂ H ₂ mixed gas.
Bake at 600 ° C.

Although high temperature sintering is preferable for ceramming, silver, palladium, gold, ruthenium, etc.
Since it melts at 0 ° C. or higher, it is preferable to bake at a temperature lower than that.

Next, a conductive paste or a conductive coating is applied to the resistance film 5 on both end surfaces in the width direction of the elongated insulating piece 10, that is, on the surface where the cross section of the resistance film 5 and the groove surface 4a of the groove 4 are exposed. Conductive and apply so as to fill along the groove surface 4a, and perform baking or heat drying to form conductive portions 6 and 6 on both side surfaces of the elongated insulating piece 10 as shown in FIGS. 1, 2 and 9. To do.

Then, the elongated insulating piece 10 is divided from the position of the dividing groove 11 to form a rectangular parallelepiped chip piece 12 having conductive portions 6 and 6 formed on both end faces in the longitudinal direction, as shown in FIG. .

Next, the electroconductive portions 6 and 6 of the chip piece 12 are subjected to nickel electrolytic plating or solder plating to form electrodes 7 and 7.
To form the rectangular chip resistor 1 shown in FIGS. The electrodes 7 and 7 may be formed by applying nickel electroplating and then performing solder plating in layers on the surface of the nickel electroplating.

In the above embodiment, the grooves are formed on the first insulating plate 2 in which a plurality of grooves 4 and 4 are formed so that the longitudinal direction is substantially perpendicular to the longitudinal direction of the grooves 4 of the first insulating plate 2. A plurality of strip-shaped resistance films 5 are formed in the width direction 4 at intervals in the width direction, the second insulation plate 3 is superposed on the first insulation plate 2, and the resistance film 5 is sandwiched. The body 9 is aligned with the groove 4 and cut in the direction in which the resistive film 5 is cut in the longitudinal direction to form the elongated insulating piece 10.

Therefore, the cross section of the resistance film 5 and the groove surface 4a in which the resistance film 5 is formed are exposed, so that the resistance film 5 formed in the groove 4 of the first insulating plate 2 simply causes Second
As compared with the cross section of the resistance film 5 formed on the planes of the insulating plates 2 and 3, the surface of the resistance film 5 having a wider area can be obtained. Therefore, due to the increase in the area of the exposed resistance film 5, the elongated insulating piece 10 is
The connection with the conductive portion 6 formed in step 1 becomes extremely strong, and a highly reliable electrode can be obtained.

In the above embodiment, the groove 4 may be formed in a discontinuous shape corresponding to the width dimension of the strip-shaped resistance film 5.

Further, if necessary, one chip piece 12 has two pieces.
It is also possible to form the resistive film 5 having more layers.

Further, although the groove 4 is formed only on the first insulating plate 2 in the description, the groove of the first insulating plate 2 is formed on the plane of the second insulating plate 3 facing the first insulating plate 2. It is also possible to provide a groove 4 corresponding to 4. Further, although the resistance film 5 is continuously formed in the orthogonal portion in the groove 4, it may be continuously formed in the entire region in the groove 4.

[0032]

According to the method for manufacturing a rectangular chip resistor of the present invention, a strip-shaped resistance film is continuously formed in the groove formed in the first insulating plate, and the first and second insulating plates are formed. Since the laminated insulator sandwiched by is aligned with the groove and cut, the resistance film formed over the inner surface of the groove of the first insulating plate is exposed, the exposed area of the resistance film increases, and The connectivity with the conductive part can be improved.

[Brief description of drawings]

FIG. 1 is a longitudinal cross-sectional side view showing a rectangular chip resistor of an embodiment manufactured by a method of manufacturing a rectangular chip resistor according to the present invention.

FIG. 2 is a sectional view in the width direction of the same.

FIG. 3 is a plan view of the same.

FIG. 4 is a perspective view showing a first insulating plate of the same.

FIG. 5 is a perspective view showing a situation in which a groove is formed in the first insulating plate.

FIG. 6 is a perspective view showing a situation in which a resistance film is formed on the first insulating plate of the same.

FIG. 7 is a perspective view showing a laminated insulator in a state in which a second insulating plate is overlapped with the above.

FIG. 8 is a perspective view showing the same elongated insulating piece.

FIG. 9 is a plan view showing a situation in which a conductive portion is formed on the elongated insulating piece of the above.

FIG. 10 is a plan view showing the same chip piece.

[Explanation of symbols]

 1 Rectangular Chip Resistor 2 First Insulating Plate 3 Second Insulating Plate 4 Groove 5 Resistive Film 6 Conductive Part

Claims (1)

[Claims] 1. A plurality of grooves are formed substantially parallel to each other on a first insulating plate with a space therebetween, and a longitudinal direction is continuous in the groove on a surface of the first insulating plate on which the groove is formed. Then, a plurality of strip-shaped resistance film layers are formed substantially perpendicular to the longitudinal direction of the groove and at substantially the same distance, and then on the surface of the first insulating plate on which the resistance film layer is formed. A second insulating plate on top of each other, and the resistive film layer is sandwiched between the first and second insulating plates to form a laminated insulator, and the laminated insulator is formed on the first insulating plate. The resistance film layer is cut along the longitudinal direction in line with the formed grooves to form elongated insulating pieces, and conductive portions are formed on both side surfaces of the elongated insulating piece where the resistive film is exposed. A method for manufacturing a rectangular chip resistor, characterized in that each is cut into chips from an intermediate position between the resistance films.