JP2002057009A - Resistor and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shunt resistor for large current measurement having good characteristics and a method for manufacturing the resistor. SOLUTION: The shut resistor 100 is constituted by a resistor 110 made of an alloy of a noble metal or a metal, high-conductivity electrodes 121 and 122, and molten 131 and 132. The resistor 110 and electrodes 121 and 122 are firmly joined to each other and the resistor 110 has no resistance adjusting notch. Consequently, the resistor 100 shows a low resistance value and a low resistance value changing rate, has a small TCR value, and, accordingly, is suitable for measuring large currents with accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistor and a method of manufacturing the same, for example, a resistor having a low resistance element portion suitable for detecting a high current and an electrode made of a metal conductor having high conductivity, and a method of manufacturing the same.

[0002]

2. Description of the Related Art It is well known to use a resistor (shunt resistor) having an extremely small resistance of about milliohm for detecting a large current. In the detection of the large current I (A) using the shunt resistor, the shunt resistor R (Ω) having a known low resistance value and a small variation in the resistance value is supplied to the high current I (A).
(A), the voltage drop V (V) at both ends of the shunt resistor is measured, and the current value I is calculated using I = V / R.
(A) is calculated.

FIG. 7 shows an example of a shunt resistor. The shunt resistor 1000 includes a metal resistor portion 1400 and two electrode portions 1100. Resistance section 14
00 is, for example, a Cu—Ni alloy (for example, CN49).
A metal alloy such as R) is used. The electrode 1100 includes
Solder plating 1200 is applied in consideration of solderability.

Here, the characteristics of the shunt resistor are determined by the temperature coefficient of resistance (TCR: Temperature Coef).
The evaluation is made using a change in resistance value (life test) before and after the use of a shunt resistor under a predetermined condition for a long time (for example, 1000 hours).

Here, the temperature coefficient of resistance (TCR) is
The resistance change ΔR / R before and after the life test of 1000 hours, which is obtained by the equation (1), is evaluated using the equation (2).

[0006] _{TCR = ((R 1 -R 0} ) / R 0) × (1 / (T 1 -T 0)) (1) R1: resistance value at the measurement temperature _{T 1 (Ω), T 1} : Measurement Temperature R0: the resistance value at the reference temperature _{T 0 (Ω), T 0} : a reference temperature _{ΔR / R = (R 1000 -R} 0) / R 0 (2) R 1000: resistance after the life test for 1000 hours (Omega) R ₀ : resistance value before the life test (Ω) Further, in order to mount the shunt resistor on a printed wiring board or the like, it is necessary to reduce the size of the shunt resistor and make the structure suitable for high-density mounting. .

[0007]

By the way, in order to measure a large current with high accuracy using a shunt resistor, the temperature coefficient of the set resistor, which is the characteristic of the shunt resistor, is brought as close as possible or when the shunt resistor is used. It is necessary to reduce the change over time of the resistance. Further, it is necessary to improve a voltage (V) -current (I) characteristic by reducing a change in resistance value with respect to a current when a large current flows.

[0008] In the shunt resistor 1000 shown in FIG.
Use a laser processing machine or the like to obtain a predetermined resistance value.
Several cuts indicated by 300 are made in the resistance portion 1400. The cut 1300 is necessary for resistance adjustment, but causes deterioration of the characteristics of the shunt resistor 1000.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a shunt resistor for measuring a large current having good characteristics and a method of manufacturing the shunt resistor.

[0010]

A method of manufacturing a resistor according to the present invention for achieving the above object has the following arrangement.
That is, a method of manufacturing a resistor having a resistor made of a resistance alloy and an electrode made of a metal having high conductivity,
A bonding step of laminating the substantially plate-shaped resistance alloy and the substantially plate-shaped metal having high conductivity, and bonding a contact interface between the resistance alloy and the metal to form a bonded body; Removing a predetermined range of the metal surface of the body from the metal surface to the contact interface to divide the metal into at least two parts to form the electrodes; and forming a plurality of resistors by dividing the joined body And a dividing step.

[0011] For example, the method further comprises a step of forming a solder layer on the electrode.

Further, for example, the method is characterized in that the method further comprises a step of adjusting the resistance value of the formed resistor.

[0013] For example, the alloy for resistance may be a copper-nickel alloy, a nickel-chromium alloy, an iron-chromium alloy, a manganese-copper-nickel alloy, a platinum-palladium-silver alloy, a gold-silver alloy, a gold-platinum-alloy. Silver alloy.

Further, for example, the electrode is made of copper or an alloy containing copper.

Further, a resistor according to the present invention for achieving the above object has the following configuration. That is, it has at least two electrodes made of a metal having high conductivity and separated from each other, and a resistance portion made of a substantially plate-shaped resistance alloy and electrically and mechanically coupled to the electrodes.

[0016] For example, the alloy for resistance may be a copper-nickel alloy, a nickel-chromium alloy, an iron-chromium alloy, a manganese-copper-nickel alloy, a platinum-palladium-silver alloy, a gold-silver alloy, a gold-platinum alloy. Silver alloy.

Further, for example, the electrode is made of copper or an alloy containing copper.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

The alloy composition used as the resistor of the shunt resistor described in the present embodiment is an example, and unless otherwise specified, the scope of the present invention is limited to these. It is not intended to be performed, but is determined according to the required characteristics and specifications of the shunt resistor to be manufactured.

[Structure of Shunt Resistor] FIG.
1 shows a shunt resistor 100 according to the present embodiment soldered on a conductor pattern 40. Shunt resistor 1
Reference numeral 00 denotes a metal resistor 110 and electrodes 121 and 122 serving as connection terminals.

The shunt resistor 100 has two rectangular parallelepiped electrodes 12 on a resistor 110 having one rectangular parallelepiped shape.
1 and 122 are joined as shown in FIG. The thickness of the resistor is about 100-1000 μm. Also,
Each electrode has a thickness of about 10 to 300 μm. On the surface of each electrode, a solder film of about 2 to 10 μm is formed.

The shunt resistor 100 is designed to easily dissipate heat. For example, an aluminum substrate is used as the substrate 140 when mounted on a printed wiring board or the like. The substrate 140 is also connected to a heat sink or the like. Structure.

That is, since the heat generated in the shunt resistor 100 when a high current is measured is transmitted in the direction of the substrate 140, the junction surface between the shunt resistor 100 and the substrate 140 is important. The container 100 is a substrate 1
A feature is that a thick copper plate having good heat conductivity is used for the electrodes 121 and 122, which are the bonding surfaces with 40, and the bonding area is large.

The current for measuring the high current flows from the pattern of the substrate 140 to the resistor 110 via one electrode 121 of the shunt resistor 100, and further flows from the resistor 110 to another electrode 122. And flows. Further, a voltage drop between the electrode 121 and the electrode 122 when a high current is applied, that is, a voltage drop at both ends of the shunt resistor 100 is measured. Therefore, the shunt resistor 10 having the structure of FIG.
0 means that a large current can be used.

As a material for the resistor 110, for example, C
A u-Ni alloy (such as CN49R), various metal alloys and various noble metal alloys shown in FIG. 4 are used, and a metal alloy or a noble metal that conforms to various characteristics such as specific resistance, TCR, and resistance change determined according to specifications. An alloy or the like is appropriately selected from FIG. 4 and used. Further, other than FIG. 4, for example, a manganese-copper-nickel alloy may be used.

As shown in FIG. 4, when a noble metal alloy is used, a resistor 110 having an extremely low electric resistance of about 2 to about 7 μΩ · cm is obtained. When used as body 110,
The resistance value of the shunt resistor 100 having the structure shown in FIG. 1 is about 0.04 to 0.15 mΩ.

As a material of the electrodes 121 and 122, a copper material (for example, about 1.5 μΩ · cm) having a lower electric resistance than the resistor 110 is used.
0 and the electrode 121 or the resistor 110 and the electrode 122 are joined by cladding. The electrode surfaces of the two electrodes 121 and 122 are designed to have a large electrode area so that heat is easily transmitted in the direction of the substrate 140 in order to easily radiate heat generated when measuring a high current. It is characterized by using a thick copper plate having good thermal conductivity and having a large bonding area.

On the surfaces of the electrodes 121 and 122,
In order to improve the solderability of the substrate to the conductor pattern, for example, films 131 and 132 of a molten solder material (Sn: Pb = 9: 1) or a lead-free solder material are formed. The molten solder is a copper electrode 121 or 12.
Since a diffusion layer is provided between the electrodes, the bonding strength and electrical reliability of the electrodes are improved.

The characteristic of the shunt resistor 100 is that the resistor 110 has a simple structure consisting of a flat plate, and the notch 1 as seen in the conventional shunt resistor 1000 is used.
There is no 300. As described above, since there is no cut in the resistor 110, the current path when a large current flows is stabilized, and the change in resistance value (ΔR / R) can be suppressed to about 0.1% or less. The resistance value change in a certain case (Δ
R / R) 1 / Several 10
It can be reduced to about 1/200.

The resistor 110 has a resistance of about 2 to 7 μΩ · cm.
When a noble metal alloy having an extremely low electric resistance is used, the resistance of the shunt resistor 100 is about 0.04 to about 0.04.
Since it is 0.15 mΩ, a shunt resistor suitable for measuring a high current can be obtained.

[Method of Manufacturing Shunt Resistor] Next, FIG.
A method for manufacturing the shunt resistor 100 will be described below with reference to FIGS. FIG. 2 shows a shunt resistor 10
FIG. 3 shows an example of a manufacturing method of the shunt resistor 100, and FIG. 3 shows the shape of each material used in each manufacturing step of FIG.

In FIG. 2, as the copper alloy 230 of the electrode material, for example, a copper material having a specific resistance of about 1.5 μΩ · cm is selected, and is processed to a predetermined size in a material processing 240 step.

The resistance material alloy 210 is selected, for example, from various metal alloys and various noble metal alloys having a predetermined specific resistance shown in FIG. 4 according to applications and specifications. It is processed to a predetermined size.

Next, a copper material shown at 120 in FIG. 3 and a resistor shown at 110, for example, a noble metal alloy, are clad-bonded in a bonding 250 step. Since the interface between the resistor 110 and the electrode 120 in the joined body 310 is firmly connected by the diffusion layer, the joining strength and the electrical reliability between the resistor 110 and the electrode 120 are improved.

Next, a part of the electrode 120 is removed from the joined body 310 so as to form a joined body having a predetermined shape shown by 320 in FIG. For example, using a cutting device, the central portion 123 of the electrode 120 shown at 320 in FIG. 3 is removed until the resistor 110 is exposed.
20 is divided into 121 and 122. The thickness of the electrode 121 and the electrode 122 is about 10 to 300 μm. Also,
The thickness of the resistor 110 is about 100 to 1000 μm.

Next, the joined body 320 is formed by the molten solder processing 2.
In step 70, 131 is applied to the surfaces of the electrodes 121 and 122.
And 132, a solder film of about 2 to 10 μm is formed,
The joined body 330 is obtained. As the solder used at this time, for example, a molten solder material (Sn: Pb = 9: 1) or a lead-free solder material is used.

Since a diffusion layer is formed between the molten solder material and the copper electrode 120, the molten solder material 131 is formed.
The electrode 121 and the molten solder material 132 and the electrode 122 are firmly joined. Therefore, the bonding strength at the interface between them is high, and the electrical reliability is improved.
It becomes possible to solder the shunt resistor 100 to the conductor pattern of the aluminum substrate 140 via 31 and 132.

Next, the joined body 330 is cut to a predetermined length using a laser processing machine, a press machine, a wire electric discharge machine, a disk cutting machine or the like in a cutting process 280 step, and shown by 340. A joined body having predetermined dimensions, for example,
A thickness of about 0.1-20 mm is obtained.

Next, the joined body 340 is adjusted to have a predetermined resistance value in a resistance adjusting 290 step. That is, while measuring the resistance value of the joined body 350, a part of the side surface and the surface of the joined body 350 is removed by using a sandblasting method or various cutting machines such as a laser processing machine. As a result, the shunt resistor 10 having a predetermined resistance value
0 is obtained.

[Characteristics of Shunt Resistor] An example of the resistance value of the shunt resistor manufactured using the various metal alloys and various noble metal alloys shown in FIG. 4 will be described below. For example, FIG.
The resistance value of the shunt resistor having the structure shown in FIG. 1 when a low-resistance noble metal alloy having a low resistance of about 2 to about 7 μΩcm is used is about 0.05 to 0.14 mΩ, and a shunt having a low resistance value is used. A resistor is obtained.

FIG. 5 shows a Cu—Ni alloy CN49.
2 is shown as an example of the TCR value of the shunt resistor 100 manufactured by the present manufacturing method of FIG. FIG. 5 also shows, for comparison, the TCR value of the shunt resistor 1000 manufactured by the conventional method shown in FIG. 7 and the change in the resistance value after a life test of 1000 hours. From FIG.
The shunt resistor 100 manufactured by this manufacturing method has a TCR value of about 1/3 or less and a change in resistance value of 1
/ 20 to 1/30 or less, and it can be seen that each characteristic is improved.

Here, CN49 which is a Cu—Ni alloy is used.
Has a TCR value of about 50 ppm / ° C., which is very close to the TCR value of the shunt resistor 110. From this, the shunt resistor 110 manufactured by the present manufacturing method is
This can be said to be a manufacturing method that can substantially reproduce the original TCR value of the i-based alloy (CN49). Also, in the shunt resistor 1000 manufactured by the conventional manufacturing method, the cut 1400 for adjusting the resistance has the original T-value of the Cu—Ni alloy (CN49).
It can be said that it works as an inhibiting factor that cannot express a CR value.

Although not shown in FIG. 5, each of the metal alloys or base metal alloys shown in FIG. Was changed.
As a result, substantially the same TCR value and resistance value change value as those in FIG. 5 were obtained. From these facts, the shunt resistor 100 manufactured by using the metal alloy or each base metal alloy shown in FIG. 4 as the resistor 110 and manufactured by the manufacturing method of FIG. It is understood that it is possible.

FIG. 6 shows the results of measuring the voltage (V) -current (I) characteristics of the shunt resistor 100 of the present embodiment shown in FIG. 5 and the shunt resistor 1000 of the conventional example. . From the results of FIG. 6, it is possible to suppress the change in the resistance value of the shunt resistor 100 having no cut in the resistor 110 with an increase in the current value to 0.1% or less, and to obtain an excellent voltage (V) -current ( I) Characteristics were obtained.

On the other hand, in the shunt resistor 1000 having a large number of cuts in the resistor, the resistance increases by several to 20% as the current increases, and the resistance changes greatly when a large current flows. This is because the current path is not stable if there is a cut. From this, it can be seen that in order to reduce the change in the resistance value of the shunt resistor when a large current flows, a shape without a cut is desirable.

As described above, according to the present embodiment, when fabricating a shunt resistor, a low-resistance material such as a noble metal alloy is used as a resistor, and no further cut is made in the resistor for adjusting the resistance. By producing a shunt resistor by using the above method, a shunt resistor having a low resistance and a small resistance change rate and having a current path suitable for measuring a high current can be provided.

[0047]

As described above, according to the present invention, it is possible to provide a shunt resistor for measuring a large current having good characteristics and a method of manufacturing the shunt resistor.

[Brief description of the drawings]

FIG. 1 is a schematic structural view of a shunt resistor according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a method for manufacturing a shunt resistor.

FIG. 3 is a view showing a shape of a joined body in each manufacturing process of the shunt resistor.

FIG. 4 is a diagram showing types of resistors.

FIG. 5 is a diagram comparing a TCR value of a shunt resistor and a change in a resistance value after a life test.

FIG. 6 is a diagram comparing VI characteristics of shunt resistors.

FIG. 7 is a schematic structural view of a conventional notched shunt resistor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 shunt resistor 110 resistor 121 electrode 122 electrode 131 molten solder material 132 molten solder material 140 substrate

Claims (8)

[Claims] 1. A method for manufacturing a resistor comprising a resistor made of a resistance alloy and an electrode made of a metal having a high conductivity, comprising: a substantially plate-shaped resistance alloy and a substantially plate-shaped high conductivity. A metal layer having a predetermined ratio of the metal surface of the bonded body to the contact interface by forming a bonded body by forming a bonded body by bonding a contact interface between the alloy for resistance and the metal; A step of removing the metal and dividing the metal into at least two parts to form the electrode; and a step of dividing the joined body to form a plurality of resistors. Method. 2. The method according to claim 1, further comprising the step of forming a solder layer on the electrode. 3. The method for manufacturing a resistor according to claim 1, further comprising a step of adjusting a resistance value of the formed resistor. 4. The resistance alloy is a copper / nickel alloy,
4. A nickel-chromium alloy, an iron-chromium alloy, a manganese-copper-nickel alloy, a platinum-palladium-silver alloy, a gold-silver alloy, or a gold-platinum-silver alloy. A method for manufacturing the resistor according to claim 3. 5. The semiconductor device according to claim 1, wherein the electrode is made of copper or an alloy containing copper.
Item 13. The method for manufacturing a resistor according to item 1. 6. A resistor having at least two electrodes made of a metal having high conductivity and separated from each other, and a resistor portion made of a substantially plate-shaped resistor alloy electrically and mechanically coupled to the electrodes. vessel. 7. The resistance alloy is a copper / nickel alloy,
7. A nickel-chromium alloy, iron-chromium alloy, manganese-copper-nickel alloy, platinum-palladium-silver alloy, gold-silver alloy, gold-platinum-silver alloy, The resistor as described. 8. The resistor according to claim 6, wherein the electrode is made of copper or an alloy containing copper.