JP2001118701A - Low-resistance resistor for detecting current and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-resistance resistor for detecting current which can be reduced in manufacturing cost by simplifying its manufacturing process and reducing the number of parts and, at the same time, can be improved in heat radiating property, and a method for manufacturing the resistor. SOLUTION: A low-resistance resistor 1 for measuring current has a recessed groove 3 formed by cutting the central part of the rear surface of a rectangular flat metallic resistance body 2 having a thickness of about 1-2 mm. On the front surface of the resistance body 2, a pair of electrode pads 4 and 4 for bonding is formed by successively plating copper and nickel in the central parts of both end sections. On the rear surface of the body 2, in addition, a pair of electrodes 5 and 5 to be connected to a printed board, etc., is formed by successively plating copper, nickel, and solder in both end sections on both sides of the groove 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detecting low resistor and a method of manufacturing the same, and more particularly to a current detecting low resistor having an electrode for connecting to an external circuit by wire bonding and a method of manufacturing the same. .

[0002]

2. Description of the Related Art Conventionally, as a low resistor for current detection, one having a structure as shown in FIG. 7 is known. This is because a low-resistance metal plate 41 made of a manganin plate or the like and a copper plate 42 for heat dissipation are laminated with an alumina plate 43 serving as an insulator interposed therebetween, and the copper plate 42 on the back side is used for bonding to a printed board or the like. Gold plated layer 44 is formed. On the other hand, both ends of the surface of the metal low-resistance body 41 are plated with nickel to form a pair of bonding electrode pads 45.

[0003] Such a current detecting low resistor is mounted on a printed circuit board or the like via a gold plating layer 44, and wire bonding is performed on a pair of electrode pads 45, so that a current flowing through the metal low resistor 41 is detected. The size can be measured.

[0004] This current detecting low resistor is manufactured as follows. That is, first, the sheet-shaped heat-dissipating copper plate 4
2, the alumina plate 43, and the metal low-resistance body 41 are laminated in this order to form a three-layer, multi-cavity laminate. Next, a resist is applied on the copper plate 2 and patterned to form a resist pattern on the portion to be cut. Then, gold plating is applied to portions other than the portion to be cut, and then the resist pattern is peeled off and separated by the portion to be cut. The gold plating layers 44 thus arranged are arranged in a matrix. Next, a resist is applied to the surface of the metal low-resistance body 41, and patterning is performed to form a resist pattern having openings in a pair of electrode pad planned portions. Then, the opening is plated with nickel, and then the resist pattern is peeled off. Thus, a pair of electrode pads 45 are formed in a matrix.

[0005] Next, a resist is applied to the surface of the metal low-resistance body 41, patterning is performed to form a resist pattern in a portion other than the portion to be cut, and then etching is performed to remove the metal low-resistance in the portion to be cut. The body 41 is removed. Thereafter, the resist pattern is peeled off to form a cutting groove for cutting each resistor from the sheet-shaped multi-piece substrate. Next, after a resist pattern is formed on the copper plate 42 on the rear surface side in a portion other than the portion to be cut in the same manner, etching is performed to remove the copper plate 42 at the portion to be cut. Thereafter, the resist pattern is peeled off to form a cutting groove for dividing the sheet-shaped multi-piece substrate into individual resistors. Next, trimming adjustment of each metal low-resistance body 41 is performed by a laser or the like. Next, cutting is performed along the cutting grooves to obtain individual chip-shaped low resistors.

[0006]

However, the conventional low resistance for current measurement has a problem that the manufacturing process is complicated and the number of parts is large, so that the manufacturing cost is high. In addition, since the alumina plate is interposed, there is a problem that heat radiation is necessarily inferior. Also,
There is a problem that the accuracy of measuring the resistance value varies during wire bonding of the electrodes.

The present invention has been made in view of the above circumstances, and has a simple manufacturing process, a small number of parts, a low manufacturing cost, and a current detecting low resistor excellent in heat dissipation. It is an object of the present invention to provide a manufacturing method thereof.

[0008]

According to a first aspect of the present invention, there is provided a low current detecting resistor according to the first aspect, wherein a central portion of a rear surface of a plate-shaped metal resistor is cut to form a concave portion. ,
A pair of bonding electrode pads are formed at both ends of the front surface, and a pair of connection electrodes are formed at both ends of the rear surface adjacent to the recess.

[0009] This makes it possible to cut the plate-shaped metal resistor material and to form a pair of electrode pads and a pair of connection electrodes on the front and back surfaces, respectively. Become simple. In addition, the number of components is small because the resistor is formed of a metal resistor material plate. Therefore, manufacturing costs can be reduced. Also, since it is formed of a metal resistor material, it has excellent heat dissipation.

According to a second aspect of the present invention, there is provided a method for manufacturing a low-resistance resistor for current detection, wherein a resist pattern is formed on each of the front and back surfaces of a plate-shaped metal resistor material, and then a pair of electrolytic plating is performed on the front surface. A pair of connection electrodes are formed on the electrode pad and the back surface side, and a concave portion is formed by cutting a portion between the pair of connection electrodes in the metal resistor material. This makes it possible to easily manufacture a current detection low resistor by performing electrolytic plating using the resist pattern and performing cutting.

According to a third aspect of the present invention, there is provided a method for manufacturing a current detecting low resistor, comprising: applying a plating film mask to each of the front and back surfaces of a plate-shaped metal resistor material; A pair of electrode pads and a pair of connection electrodes are formed on the back surface side, and a concave portion is formed by cutting a portion between the pair of connection electrodes in the metal resistor material. Thus, the current detecting low resistor can be easily manufactured by performing the electrolytic plating using the plating film mask and performing the cutting process.

According to a fourth aspect of the present invention, there is provided a current detecting low resistor.
The pair of electrode pads are formed by performing copper plating and further performing nickel plating. Thereby, since the copper plating is performed, the accuracy of the variation in the resistance value is improved.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, the current measuring low resistor 1 according to the present embodiment is a rectangular plate having a thickness of about 1 to 2 mm made of a manganin plate, a copper-nickel plate, a nickel-chromium plate, or the like. The central portion of the back surface of the metal resistor 2 is cut to form a concave groove (recess) as shown in the figure.
3 are formed. Copper plating is applied to the center of both end portions (thick portions) of the surface of the metal resistor 2 and nickel plating is applied to form a pair of bonding electrode pads 4 and 4. Nickel plating and solder plating are sequentially applied to both ends (thick portions) of the metal resistor 2 with the concave groove 3 interposed therebetween, so that a pair of connection electrodes 5 and 5 to a printed board or the like are provided. Is formed.

The current detecting low resistor 1 is mounted on a printed circuit board or the like, and a current terminal is connected to the pair of electrodes 5 and 5. On the other hand, the wire bonding for measuring the sense voltage is performed on the pair of electrode pads 4 and 4, and the voltage between them can be measured as the sense voltage. Thereby, the magnitude of the current flowing through the metal resistor 1 can be measured.

In this current detecting low resistor 1, a plate-shaped metal resistor material is cut to form a concave groove 3 in the center of the back surface, and a pair of electrode pads 4 are formed on the front and back surfaces, respectively. , 4 and a pair of connection electrodes 5, 5, so that the manufacturing process can be simplified. In addition, since it can be manufactured from a metal resistor material plate, the number of parts can be reduced. For this reason, manufacturing costs can be reduced. Furthermore, since it is formed of a metal resistor material, heat dissipation can be improved. Further, since the pair of bonding electrode pads 4 and 4 are plated with copper, it is possible to improve the accuracy of the variation in the resistance value.

Next, a method of manufacturing the current detecting low resistor 1 will be described with reference to FIGS. First,
A sheet-shaped metal plate (metal resistor material) 11 of, for example, about 10 cm square and having a thickness of about 1 to 2 mm, which is made of a manganin plate, a copper-nickel plate, a nickel-chrome plate, or the like, is prepared. Next, as shown in FIG.
The connection electrodes 5 and 5 are formed in a strip shape on the back surface of the. This is because the resist pattern 12 is formed in portions other than the portions where the connection electrodes 5 and 5 are to be formed, and nickel and solder plating are continuously performed on the openings. Next, the resist pattern 12 is peeled off. Next, as shown in FIG. 3B, the groove 3 is formed by cutting the space between the pair of electrodes 5 and 5 by machining or laser processing so as to have a thickness of about half.

Next, as shown in FIG. 3C, electrode pads 4 and 4 are formed in a matrix on the surface of the metal plate 11. This is because the resist pattern 13 is formed in a portion other than the portions where the electrode pads 4 and 4 are to be formed, and copper and nickel plating are continuously performed on the opening. Next, the resist pattern 13 is peeled off. Next, cutting is performed along the cutting line 14 in the vertical and horizontal directions to obtain individual chip-shaped low resistors 1. Next, trimming adjustment is performed by making a cut with a laser or the like. Next, after the measurement and inspection, taping is sequentially performed by an automatic taping device.

In the manufacturing method of the present embodiment, a large number of low resistors 1 are manufactured in a matrix using the square metal plate 11, but the low resistance is manufactured using the strip metal plate. The containers 1 may be manufactured continuously in a line.

FIG. 4 and FIG. 5 are a plan view and a side view showing a current measuring low resistor 21 according to another embodiment of the present invention. In these drawings, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be simplified. The current measuring low resistor 21 has a pair of bonding electrode pads 24, 24 formed on the entire surface of both ends of the surface of the metal resistor 2.
5 and 25 are formed by applying copper plating, nickel plating, and further solder plating, which are different from the above-described low resistance 1 for current measurement, but other configurations are the same.

Next, a method for manufacturing the current detecting low resistor 21 will be described with reference to FIGS. 6 (a) to 6 (g). Note that, in these figures, the same components as those in FIGS. 3A to 3C are denoted by the same reference numerals, and description thereof will be simplified. First, as shown in FIG. 6A, a thickness of 1 to 2 made of a manganin plate, a copper-nickel plate, a nickel-chrome plate, or the like is used.
Attaching plating film masks 32a and 32b, such as organic acid-resistant tapes, respectively, to the front and back surfaces of a strip-shaped metal plate (metal resistor material) 31 of about mm except for both side ends along the longitudinal direction. I do. Next, as shown in FIG. 6B, the film masks 32 a on the front and back surfaces of the metal plate 31,
Copper plating and further nickel plating are applied to portions other than 32b, respectively, and a pair of electrode pads 24 and 24 and a pair of electrodes 25 and
25 are continuously formed on both sides of the metal plate 31 in a strip shape. Next, as shown in FIGS. 6C and 6D, the film masks 32a and 32b are peeled off.

Next, as shown in FIGS. 6 (e) and 6 (f), the portion between the electrodes 25, 25 of the metal plate 31 is reduced to about half the thickness by machining or laser machining. And the concave groove 3 is continuously formed. Next, after masking for solder plating, a pair of electrodes 2
5, 25 are plated with solder. Next, after cutting as shown by a dashed line in FIG. 6E to obtain individual chip-shaped low-resistance devices 1, as shown in FIG. To adjust the trimming. Next, after the measurement and inspection, taping is sequentially performed by an automatic taping device.

Although the band-shaped metal plate 31 is used in the manufacturing method of this embodiment, a large number of low-resistance resistors 1 may be formed in a matrix using a square-plate-shaped metal resistor material instead. May be manufactured at the same time.

[0023]

As described above, according to the present invention,
Since it can be manufactured by pressing a plate-shaped metal low-resistance material and forming a pair of electrode pads and a pair of connection electrodes on the front and back surfaces respectively, the manufacturing process can be simplified. it can. And since it can be manufactured from a plate-shaped metal low-resistance material, the number of parts can be reduced, and the manufacturing cost can be reduced. Furthermore, since it is formed of a metal low-resistance material, heat dissipation can be improved. In addition, since the pair of electrode pads are plated with copper, the accuracy of resistance value variation is improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a current detection low resistor according to an embodiment of the present invention.

FIG. 2 is a side view of FIG.

3A and 3B are views for explaining a method of manufacturing the current detection low resistor according to the embodiment of the present invention, wherein FIG. 3A is a rear view, FIG. 3B is a side view, and FIG. FIG. 3C is a plan view.

FIG. 4 is a plan view showing a current detection low resistor according to another embodiment of the present invention.

FIG. 5 is a side view of FIG. 4;

FIG. 6 is a diagram for explaining a method of manufacturing a current detection low resistor according to another embodiment of the present invention.
6 (a) to 6 (c) are plan views, FIG. 6 (d) is a cross-sectional view, FIG. 6 (e) is a rear view, FIG. 6 (f) is a cross-sectional view, and FIG. 6 (g) is a side view. .

FIG. 7 is a side view showing a conventional low resistor for current detection.

[Explanation of symbols]

 1, 21 Low resistance for current detection 2 Metal resistor 3 Groove (recess) 4, 24 Electrode pad 5, 25 Connection electrode 11, 31 Metal plate (Metal resistor material) 12, 13 Resist pattern 32 Plating For film mask

Continued on the front page (72) Inventor Katsumi Takagi 14016 Nakaminowa, Minowa-machi, Kamiina-gun, Nagano Prefecture Inside the Koa Co., Ltd. Person Hiroshi Kato 14016 Nakaminowa, Minowa-cho, Kamiina-gun, Nagano Prefecture F-term (reference) 5E028 AA10 BA21 BB01 CA02 DA04 JA00 JB00 JC03 JC06 5E032 AB10 BA21 BB01 CA02 CC11 CC14 5E033 AA00 BC07 BD01 BG03 BH01

Claims (4)

[Claims] 1. A central portion of a rear surface of a plate-shaped metal resistor is cut to form a recess, a pair of bonding electrode pads are formed at both ends of the front surface, and a pair of bonding electrode pads are formed at both ends of the rear surface adjacent to the recess. A low resistance for current detection, wherein a connection electrode is formed. 2. After forming a resist pattern on each of the front and back surfaces of the plate-shaped metal resistor material, electrolytic plating is performed to form a pair of electrode pads on the front surface side and a pair of connection electrodes on the back surface side. A method for manufacturing a low-resistance resistor for current detection, characterized in that a concave portion is formed by cutting a portion between the pair of connection electrodes in the metal resistor material. 3. A plating film mask is formed on each of the front and back surfaces of a plate-shaped metal resistor material, and then electrolytic plating is performed to form a pair of electrode pads on the front side and a pair of connection electrodes on the back side. Forming a recess between the pair of connection electrodes in the metal resistor material to form a concave portion. 4. The current detection low resistor according to claim 1, wherein said pair of electrode pads are formed by applying copper plating and further applying nickel plating.