JP2007189000A - Metal plate resistor and resistive body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resistive body with a proper mounting property with respect to a ceramic board, and a metal plate resistor using the resistive body, wherein when the metal plate resistor is mounted on the ceramic board as a current detecting resistor, as well, the occurrence distortions on an electrode-mounting face, due to a difference in a thermal expansion coefficient between the metal plate resistor and the ceramic board, can be prevented. <P>SOLUTION: The resistive body 10 is obtained, by laminating a resistive alloy layer 11 and a low expansion alloy layer 12, having a lower thermal expansion coefficient than the resistive alloy layer. In the metal plate resistor, electrodes 13, 13 are jointed to both ends of the resistive body 10, obtained by laminating the resistive alloy layer 11 and the low-expansion alloy layer 12. The composite thermal expansion coefficient of the resistive body 10 is close to the thermal expansion coefficient of the ceramic board. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a metal plate resistor, and more particularly to a metal plate resistor that can be suitably used as a current detection resistor mounted on a ceramic substrate and a resistor thereof.

Metal plate resistors are made of copper or nickel alloy at both ends of a resistor made of a plate-like resistor alloy such as copper / nickel alloy, copper / manganese alloy, iron / chromium alloy, nickel / chromium alloy. An electrode made of a conductive metal plate is joined (for example, see Patent Document 1).
JP 2002-184601 A

Here, the linear thermal expansion coefficient of the resistance alloy is generally 8 to 20 [× 10 ⁻⁶ / K], and the linear thermal expansion coefficient of the ceramic substrate is generally 5 to 7 [× 10 ⁻⁶ / K]. There is a big difference. Therefore, for modules in which a metal plate resistor is mounted on a ceramic substrate, if a sudden temperature change occurs in the metal plate resistor or if it is used for a long time, due to the difference in thermal expansion coefficient between them, There is a problem that a crack may occur on the electrode mounting surface (solder part) of the metal plate resistor having the weakest strength and may become open.

  The present invention has been made in view of the above-described circumstances. Even when a metal plate resistor is mounted on a ceramic substrate as a current detection resistor, the difference in thermal expansion coefficient between the metal plate resistor and the ceramic substrate is different. An object of the present invention is to provide a resistor with good mountability to a ceramic substrate that can prevent the occurrence of distortion on the electrode mounting surface due to the above, and a metal plate resistor using the resistor.

In order to solve the above problems, a metal plate resistor suitable for mounting on a ceramic substrate of the present invention is formed by laminating a resistance alloy layer and a low expansion alloy layer having a lower thermal expansion coefficient than the resistance alloy layer. A resistor and an electrode joined to both ends of the resistor are provided. Here, the coefficient of thermal expansion of the low expansion alloy layer is preferably 7 × 10 ⁻⁶ / K or less.

  By forming a resistance body in which a resistance alloy layer and a low expansion alloy layer having a lower thermal expansion coefficient than the resistance alloy layer are laminated, a low thermal expansion coefficient as a resistance body that cannot be realized only by the resistance alloy layer is obtained. . As a result, the thermal expansion coefficient of the resistor of the metal plate resistor can be made close to that of the ceramic substrate, and the above problem is solved. On the other hand, the resistance temperature coefficient (TCR) as a resistor can be made lower than when only a low expansion alloy layer having a lower thermal expansion coefficient than that of the resistance alloy layer is used as the resistor. For this reason, the characteristic more suitable as a resistor can be acquired. Moreover, according to the resistor of this invention, the design which synthesize | combines the thermal expansion coefficient of the resistor of a metal plate resistor according to the thermal expansion coefficient of the ceramic substrate to be used is attained.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, in each figure, the same code | symbol is attached | subjected to the member or element which has the same function, and the duplicate description is abbreviate | omitted.

  FIG. 1 shows a metal plate resistor according to an embodiment of the present invention. Resistance alloy layer 11 composed of a plate-like resistance alloy such as copper / nickel alloy, copper / manganese alloy, iron / chromium alloy, nickel / chromium alloy, and nickel / iron alloy or nickel / cobalt The resistor 10 is formed by laminating a low-expansion alloy layer 12 having a low thermal expansion coefficient that is made of an iron-based alloy. Electrodes 13 made of a highly conductive metal such as copper are joined to the lower surfaces of both ends of the resistor 10 to form a metal plate resistor. A plating layer such as solder plating is formed on the lower surface of the electrode 13 and is mounted on a mounting substrate such as a ceramic substrate by solder bonding.

As a selection of the material of the low expansion alloy layer, the linear thermal expansion coefficient of the ceramic substrate is generally 5 to 7 [× 10 ⁻⁶ / K], and the linear thermal expansion coefficient of the resistance alloy is generally 8 to 20 Since [× 10 ⁻⁶ / K], the resistance alloy layer, the low expansion alloy layer, and an alloy having a thermal expansion coefficient close to the thermal expansion coefficient of the ceramic are selected. As described above, the low expansion alloy layer 12 is made of a material having a low thermal expansion coefficient, which is made of nickel / iron-based alloy or nickel / cobalt / iron-based alloy.

More specifically, 42Ni—Fe (42 alloy) or 36Ni—Fe (invar) can be selected as the nickel / iron-based alloy. As the nickel-cobalt-iron-based alloy, 29Ni-17Co-Fe (Kovar) or 32Ni-4Co-Fe (Super Invar) can be selected. Further, an alloy (42 Invar) in which Ni—Co is 41 to 43%, Mn is 0.7 to 1.25%, Si is 0.3% or less, and the balance is Fe can be selected. Note that the above alloys may contain other additives and impurities. These alloys are materials having a thermal expansion coefficient of 7 × 10 ⁻⁶ / K or less. For example, Super Invar (trade name) has a coefficient of thermal expansion of about 0.7 × 10 ⁻⁶ / K.

  In this embodiment, the resistor 10 has a resistance alloy layer 11 sandwiched between low expansion alloy layers 12 and 12 from above and below. The resistor 10 has a thickness of 0.4 mm, and the electrode 13 has a thickness of 0.2 mm.

  In order to reduce the thermal expansion coefficient and prevent the TCR value from being greatly affected, it is desirable that the electrical resistivity of the resistance alloy layer 11 is smaller than the electrical resistivity of the low thermal expansion alloy layer 12, and further, these electrical resistivity A larger difference is more desirable. Even when the electrical resistivity of the resistance alloy layer 11 is larger than the electrical resistivity of the low thermal expansion alloy layer 12, it is possible to cope with the TCR characteristics by changing the thickness of each layer.

As Example 1, a copper / nickel alloy (CN49) was used for the resistance alloy layer 11 and Super Invar (trade name) (trademark “INVAR” international registration 0323755) was used for the low expansion alloy layer 12. The
Upper layer low expansion alloy layer: Resistance alloy layer: Lower layer low expansion alloy layer = 3.1: 3.8: 3.1
It was.

ここで、
α：熱膨張係数
Ｅ：ヤング率
Ｖ：体積率
すなわち、抵抗体１０の熱膨張係数は、抵抗合金層１１と低膨張合金層１２の性質（熱膨張係数、ヤング率、体積率）から算出することができる。 In this case, the combined thermal expansion coefficient α _Compound of the resistor 10 is obtained by the following equation.

here,
α: Thermal expansion coefficient E: Young's modulus V: Volume ratio That is, the thermal expansion coefficient of the resistor 10 is calculated from the properties (thermal expansion coefficient, Young's modulus, volume ratio) of the resistance alloy layer 11 and the low expansion alloy layer 12. be able to.

And the synthetic | combination TCR compound of the resistor 10 is calculated _| required by a following formula.

As Example 2, the resistance alloy layer 11 is made of an iron / chromium alloy, the low expansion alloy layer 12 is made of super invar (trade name), and the thickness ratio of each layer is
Upper layer low expansion alloy layer: Resistance alloy layer: Lower layer low expansion alloy layer = 2.5: 5.0: 2.5
It was.

As Example 3, the resistance alloy layer 11 is made of copper / manganin-based alloy, the low expansion alloy layer 12 is made of super invar (trade name), and the thickness ratio of each layer is
Upper layer low expansion alloy layer: Resistance alloy layer: Lower layer low expansion alloy layer = 2.5: 5.0: 2.5
It was.

The electrical resistivity, resistance temperature coefficient (TCR), and thermal expansion coefficient of the resistance material and the low expansion alloy material in each of the above examples are as shown in the following table.

About Example 1,2,3, the result of having calculated _| required synthetic _{| combination} electrical resistivity, synthetic _{| combination} resistance temperature coefficient TCR _Compound , and synthetic _{| combination} thermal expansion coefficient (alpha) _Compound was shown as follows by simulation.

As described above, it can be seen that the thermal expansion coefficient is greatly improved as compared with the case of only the resistance alloy, and the characteristics close to 5-7 × 10 ⁻⁶ / K which is the thermal expansion coefficient of the ceramic substrate can be obtained.

  FIG. 2 shows a modification of the embodiment shown in FIG. (A) shows an example in which the resistor 10 is formed by sandwiching the upper and lower layers as a resistance alloy layer 11 and the intermediate layer as a low expansion alloy layer 12 so as to be sandwiched. (B) is an example in which the upper layer is the resistance alloy layer 11 and the lower layer is the low expansion alloy layer 12. (C) is an example in which the upper layer is the low expansion alloy layer 12 and the lower layer is the resistance alloy layer 11. (D) is an example in which a plurality of resistance alloy layers 11 and low expansion alloy layers 12 are alternately laminated. In the illustrated case, four resistance alloy layers 11 and three low expansion alloy layer layers 12 are formed between the resistance alloy layers. Of course, the reverse is also possible.

  Next, the manufacturing method of the metal plate resistor provided with the said resistor 10 is demonstrated. First, a thin plate made of a resistance alloy for forming a resistance alloy layer and a thin plate made of a low expansion alloy having a low thermal expansion coefficient for forming a low expansion alloy layer are stacked, and pressurization (0.01 to 500 t), And heating (600 ° C. to 1200 ° C.) for bonding. As a result, the resistance alloy layer and the low expansion alloy layer are laminated, and the bonding is performed by diffusion bonding or solid phase bonding.

  In order to form the resistor 10 having the structure shown in the first embodiment, a copper / nickel alloy thin plate is sandwiched between invar thin plates, and pressed and heated to form a resistor (laminated body). Further, a thin plate of a resistor (laminated body) and a thin plate of an electrode material (for example, copper) are stacked and rolled to obtain a clad material. Then, unnecessary portions of the electrode material are removed by chemical etching, and the electrodes 13 and 13 are separated from both ends of the resistor 10.

  As other methods, the electrodes 13 and 13 may be formed by bonding two rows of electrode materials to the resistor material, or the electrodes 13 and 13 may be separated by cutting using a milling machine or the like. Good. At this time, the electrodes 13 and 13 are separated, but the low expansion alloy layer 12 is not cut entirely but left in part (that is, the resistance alloy layer is not exposed by cutting). This is because if the lower low expansion alloy layer is cut, the balance with the upper low expansion alloy layer is lost, and the entire component may be warped.

  And a solder plating layer is formed in the lower surface of the electrodes 13 and 13 part, and it completes as a metal plate resistor. Even if the metal plate resistor manufactured in this way is mounted on a ceramic substrate whose thermal expansion coefficient is considerably different from that of a normal metal plate resistor, the composite thermal expansion coefficient is close to that of the ceramic substrate as described above. It operates as a highly reliable metal plate resistor with less thermal distortion.

  In the above embodiment, the example in which the plate-like electrodes are joined to the lower surfaces of both ends of the plate-like resistor and the solder plating layer is formed on the lower surface has been described. However, other types of metal plate resistors Of course, the resistor of the present invention can be used as well.

  Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea.

It is a perspective view which shows the metal plate resistor of one Embodiment of this invention. It is a perspective view which shows the various modifications of the said metal plate resistor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Resistor 11 Resistance alloy layer 12 Low expansion alloy layer 13 Electrode

Claims (9)

A resistor in which a resistance alloy layer and a low expansion alloy layer having a lower thermal expansion coefficient than the resistance alloy layer are laminated;
An electrode joined to both ends of the resistor, and a metal plate resistor. The metal plate resistor according to claim 1, wherein the low expansion alloy layer has a thermal expansion coefficient of 7 × 10 ⁻⁶ / K or less.   3. The metal plate resistor according to claim 1, wherein the resistor is formed by sandwiching the resistance alloy layer between the low expansion alloy layers.   4. The resistance alloy layer according to claim 1, wherein the resistance alloy layer is made of any one of a copper / nickel alloy, a copper / manganese alloy, an iron / chromium alloy, and a nickel / chromium alloy. Metal plate resistor.   5. The metal plate resistor according to claim 1, wherein the low expansion alloy layer is made of any one of a nickel / iron-based alloy and a nickel / cobalt / iron-based alloy.   6. The metal plate resistor according to claim 1, wherein the bonding between the resistance alloy layer and the low expansion alloy layer is performed by diffusion bonding or solid phase bonding.   A resistor comprising a resistance alloy layer and a low expansion alloy layer having a thermal expansion coefficient lower than that of the resistance alloy layer. The resistor according to claim 7, wherein the low expansion alloy layer has a thermal expansion coefficient of 7 × 10 ⁻⁶ / K or less.   9. The resistor according to claim 7, wherein the resistance alloy layer is sandwiched between the low expansion alloy layers.

Images