Layered resistor

Abstract

Provided is a layered resistor that has a low profile but still suppresses short circuiting caused by solder wetting.　A layered resistor according to the present invention includes a resistance element that has a thin plate shape and has a first flat surface and a second flat surface in the thickness direction, a first electrode that is formed on the first flat surface, and a second electrode that is formed on the second flat surface. The resistance element includes a nickel / chromium or iron / chromium metal material, the second electrode is opposite a circuit pattern when the layered resistor is mounted on a circuit board, and the thickness of the resistance element is 3–8 times the thickness of the second electrode.

Description

Multilayer Resistors

[0001] The present invention relates to a stacked resistor for sensing current.

[0002] Patent Document 1 discloses a resistor having a disk-shaped resistive element having a first plane and a second plane in the thickness direction, a first electrode formed on the first plane, and a second electrode formed on the second plane. This resistor is a vertical resistor in which current flows vertically, perpendicular to the substrate.

[0003] The vertical resistor described above has a low profile and yet has a high specific resistance that makes it suitable for use in detecting large currents.

[0004] Japanese Patent Application Laid-Open No. 2020-035851

[0005] As vertical resistors become thinner, the risk of short-circuiting between the first and second electrodes due to the solder used to mount them on a circuit board increases. For this reason, measures to prevent short-circuiting due to solder wetting are required.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a multilayer resistor that is low in height yet suppresses short circuits caused by solder wetting.

[0007] According to one aspect of the present invention, there is provided a multilayer resistor having a thin plate-shaped resistor element having a first plane and a second plane in the thickness direction, a first electrode formed on the first plane, and a second electrode formed on the second plane, wherein the resistor element contains a nickel-chromium or iron-chromium metal material, the second electrode faces a circuit pattern formed on the surface of the circuit board when mounted on the circuit board, and the thickness of the resistor element is between three and eight times the thickness of the second electrode.

[0008] According to one aspect of the present invention, a multilayer resistor is provided that is low in height and yet can suppress short circuits caused by solder wetting.

[0009] FIG. 1 is a perspective view illustrating the structure of a multilayer resistor according to this embodiment. FIG. 2 is a cross-sectional view of the multilayer resistor taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional view of a multilayer resistor according to a first modified example. FIG. 4 is a perspective view illustrating the structure of a multilayer resistor according to a second modified example. FIG. 5 is a perspective view illustrating the structure of a multilayer resistor according to a third modified example. FIG. 6 is a perspective view illustrating the structure of a resistor according to a second modified example. FIG. 7 is a perspective view illustrating the structure of a resistor according to a third modified example.

[0010] [Multilayer Resistor] The structure of the multilayer resistor 1 of this embodiment will be described with reference to the drawings.

[0011] The multilayer resistor 1 is a resistor for detecting current, and is called a current detection resistor or a shunt resistor. The multilayer resistor 1 is mounted on, for example, a power module and used for detecting large currents.

[0012] FIG. 1 is a perspective view illustrating the structure of a multilayer resistor 1 (hereinafter referred to as resistor 1) according to this embodiment, and FIG. 2 is a cross-sectional view of resistor 1 taken along line II-II in FIG.

[0013] In this embodiment, the resistor 1 is formed in the shape of a thin plate and includes a resistive element 11 made of a resistive material, a first electrode 21 and a second electrode 22 .

[0014] The resistor 11 has a first plane 11A and a second plane 11B in the thickness direction. A first electrode 21 is formed on the first plane 11A. A second electrode 22 is formed on the second plane 11B.

[0015] That is, the resistor 1 has a laminated structure in which a first electrode 21, a resistive element 11, and a second electrode 22 are laminated in this order.

[0016] In the resistive element 11 of the resistor 1 according to this embodiment, a current path is formed in the thickness direction D (lamination direction) shown in Figures 1 and 2. Therefore, the current path is shorter than the current path of a general shunt resistor. In the resistor 1, in order to achieve miniaturization, particularly to achieve thinning in the lamination direction (low profile), the thickness d of the resistor 1 is formed to be thin.

[0017] In this embodiment, from the viewpoint of forming the resistor 1 thinner, it is preferable that the thickness d of the entire resistor 1 is 2 mm or less.

[0018] Furthermore, when the resistor 1 and the circuit board are connected by wire bonding, it is more preferable that the thickness d of the entire resistor 1 is 1 mm or less.

[0019] <Electrodes> The first electrode 21 and the second electrode 22 are electrodes for passing a current in the thickness direction D of the resistor 11. The first electrode 21 and the second electrode 22 are generally formed using a metal material capable of forming electrodes. In this embodiment, the first electrode 21 and the second electrode 22 are formed using a metal material with high conductivity. As an example of such a metal material, copper (Cu) is preferably used.

[0020] In this embodiment, the first electrode 21 is located on the upper surface side above the surface of the circuit board when mounted on the circuit board, and the second electrode 22 faces the circuit pattern formed on the surface of the circuit board when mounted on the circuit board.

[0021] In this embodiment, the thickness T1 of the first electrode 21 and the thickness T2 of the second electrode 22 can be set to the same value. That is, in this embodiment, T1 = T2. As an example, the thickness T1 of the first electrode 21 is preferably set to 0.01 mm to 0.07 mm.

[0022] If the first electrode 21 is thinner than 0.01 mm, the resistance characteristics of the resistor 1 are likely to change depending on the wire bonding position due to the potential distribution in the first electrode 21, and detection accuracy will decrease. Furthermore, by ensuring that the thickness T1 of the first electrode 21 does not exceed 0.07 mm, the first electrode 21 can function as a thin plate electrode of the resistor 1 and can contribute to reducing the height of the resistor 1.

[0023] The thickness T1 of the first electrode 21 is more preferably 0.01 mm to 0.03 mm from the viewpoint of maintaining the function as an electrode for the vertical resistor 1. The thickness T1 of the first electrode 21 is still more preferably 0.03 mm.

[0024] From the viewpoint of reducing the height, the first electrode 21 may be formed thinner than the second electrode 22. In this case, it is preferable that the thickness T1 of the first electrode 21 is 0.1 to 0.5 times the thickness T2 of the second electrode 22, within a range that does not affect the resistance characteristics of the resistor 1.

[0025] In this embodiment, the thickness T2 of the second electrode 22 is preferably 0.1 mm or more and 0.15 mm or less, from the viewpoint of forming a good solder ferret when mounting the resistor 1 on a circuit board.

[0026] In this embodiment, forming an electrode by plating is an effective way to form a thin electrode with low resistivity, as it can provide a resistance value equivalent to that of a simple metal, i.e., a bulk metal.

[0027] Furthermore, the plating method makes it possible to form the first electrode 21 and the second electrode 22, which are difficult to produce by a method of bonding a bulk metal body to a resistor by welding or the like.

[0028] In this embodiment, as an example, from the viewpoint of good electrical conductivity and reducing the height of the resistor 1, it is preferable to form the first electrode 21 and the second electrode 22 made of copper plating by a plating method using copper as the metal material.

[0029] <Resistor> A resistive material having high resistivity and low wettability with solder is used for the resistor 11. In this embodiment, a nickel-chromium metal material (Ni—Cr alloy) or an iron-chromium metal material (Fe—Cr alloy) can be used as such a resistive material. Alternatively, an alloy containing a Ni—Cr alloy or an Fe—Cr alloy as a main component can be used as nichrome. The Ni—Cr alloy may be a metal consisting of only Ni and Cr, or may contain one or more metal materials selected from Mo, Al, Si, Mn, Cu, etc. The Fe—Cr alloy may be a metal consisting of only Fe and Cr, or may contain one or more metal materials selected from Mo, Al, Si, Mn, Cu, etc.

[0030] The Fe—Cr alloy has a higher resistivity than the Ni—Cr alloy, is less susceptible to solder wettability than the Ni—Cr alloy, and is magnetic. Therefore, it is more preferable to use the Ni—Cr alloy from the viewpoint of ensuring stable current detection accuracy and / or voltage detection accuracy by the resistor 1 in an environment that is susceptible to the effects of temperature, magnetic fields, etc.

[0031] In this embodiment, the thickness h of the resistor 11 is three to eight times the thickness T2 of the second electrode 22. If the thickness h of the resistor 11 is less than three times the thickness T2 of the second electrode 22, a good solder fillet cannot be formed, and the bonding strength cannot be ensured. Furthermore, if the thickness h of the resistor 11 exceeds eight times the thickness T2 of the second electrode 22, the overall thickness d of the resistor 1 becomes large, which hinders the resistor 1 from being made low-profile.

[0032] In this embodiment, the thickness h of the resistor 11 is preferably set to, for example, 0.3 mm to 0.8 mm, since the overall thickness d of the resistor 1 does not exceed 2 mm and the self-inductance value of the resistor 1 is reduced.

[0033] The resistivity (volume resistance value) of the resistor 11 according to this embodiment needs to be set to a value greater than the resistivity of the alloy alone used as the resistive material of a general shunt resistor, which is approximately 50 μΩ·cm to 100 μΩ·cm.

[0034] Furthermore, in this embodiment, in order to facilitate mounting on a circuit pattern on a circuit board or on a power semiconductor, the length R of one side of the resistor 11 can be set to be greater than the thickness h of the resistor 11. The length R of one side of the resistor 11 is required to be several millimeters. From the viewpoint of miniaturization, the length R of one side of the resistor 11 can be set to, for example, 3 mm to 6 mm. Note that FIG. 1 shows the structure of a rectangular resistor 1 as an example. The planar shape of the resistor 1 can be rectangular, square, polygonal, circular, or the like.

[0035] The resistive material 11a constituting the resistor 11 is required to be a resistive material that can be designed to have a specific resistance within the range of 130 μΩ·cm (microohm centimeters) to 200 μΩ·cm.

[0036] In this embodiment, the resistivity of the resistor 11 is preferably set within a range of 130 μΩ·cm to 150 μΩ·cm, so that even if the distance between the electrodes is shortened to meet the design requirement of reducing the height of the product, that is, even if the thickness of the resistor 1 is designed to be thin, the resistance value required for the resistor 1 as a resistor for detecting large current can be achieved.

[0037] <Solder> It is preferable that the solder used in this embodiment does not contain a flux with a strong reducing power, such as a Zn-based flux.

[0038] [Effects] The resistor 1 according to this embodiment is a thin-plate shunt resistor having a resistive element 11 having a first plane 11A and a second plane 11B in the thickness direction D, a first electrode 21 formed on the first plane 11A, and a second electrode 22 formed on the second plane 11B.

[0039] In this embodiment, the first electrode 21 is positioned so that it is located on the upper surface side above the surface of the circuit board when mounted on the circuit board, and the second electrode 22 is positioned so that it faces the circuit pattern formed on the surface of the circuit board when mounted on the circuit board.

[0040] In this embodiment, the resistor 11 made of a material containing a nickel-chromium based metal material (Ni-Cr based alloy), an iron-chromium based metal material (Fe-Cr based alloy), or an alloy containing a Ni-Cr based alloy or an Fe-Cr based alloy as a main component has a property of being difficult to wet with solder, particularly under conditions where a highly reducing Zn based flux is not used.

[0041] As a result, even though the resistor 1 is thin, the solder does not easily wet and spread to the first electrode 21 located on the upper surface of the resistor 1, thereby preventing the occurrence of a short circuit caused by the solder fillet coming into contact with the first electrode 21.

[0042] Furthermore, in the resistor 1 according to this embodiment, the thickness d of the resistive element 11 is between three and eight times the thickness T2 of the second electrode 22, which is arranged to face the circuit pattern formed on the surface of the circuit board when mounted on the circuit board.

[0043] This reduces the height of the resistor 1, while enhancing the effect of preventing the solder from wetting and spreading from the well-formed solder fillet to the first electrode 21 located above the resistor 11 when the resistor 1 is mounted on a circuit board.

[0044] Therefore, the effect of suppressing the occurrence of a short circuit due to the solder fillet coming into contact with the upper first electrode 21 can be further improved.

[0045] In this embodiment, the thickness of the second electrode 22 is 0.1 mm or more and 0.15 mm or less, so that when the resistor 1 is mounted on a circuit board, a solder fillet with sufficient strength to join the second electrode 22 to the circuit board can be secured.

[0046] When the first electrode 21 is formed thinner than the second electrode 22, the thickness of the first electrode 21 can be 0.1 to 0.5 times the thickness of the second electrode 22, 0.01 mm to 0.075 mm, or even 0.01 mm to 0.03 mm. This allows the resistor 1 to be made thinner while maintaining its function as an electrode for the vertical resistor 1 and ensuring a thickness of the second electrode 22 that allows a good solder fillet to be formed.

[0047] In this embodiment, by using the resistive element 11 having a thickness h of 0.3 mm to 1.2 mm and the above-described first electrode 21 and second electrode 22, it is possible to reduce the self-inductance value of the resistor 1 and to make the thickness d of the entire resistor 1 2 mm or less. By making the thickness d of the entire resistor 1 2 mm or less, the height of the resistor 1 can be reduced.

[0048] [Example of Mounting on Circuit Board] Fig. 3 is a schematic diagram illustrating an example of a circuit board 100 on which the resistor 1 is mounted. Fig. 4 is a schematic diagram illustrating an enlarged view of a main part of the resistor 1 on the circuit board 100.

[0049] 3 is, for example, a power module that processes high voltages and large currents. In this embodiment, the resistor 1 is mounted on the circuit board 100 and functions as a current detection resistor that detects large currents.

[0050] The circuit board 100 has a substrate 101 made of an insulating material, and current wirings 111 and 112 that constitute a circuit are formed on the substrate 101. Current detection wirings 113 and 114 that are connected to a current detection IC are also formed on the substrate 101.

[0051] 3, the resistor 1 is mounted by soldering at a predetermined location on the current wiring 111. An example of soldering the resistor 1 will be described.

[0052] First, solder paste 30 is printed at a predetermined location on current wiring 111. After that, the second electrode 22 of resistor 1 is mounted on the solder paste 30 printed at the predetermined location on current wiring 111, and in this state, the solder paste is melted and solidified under predetermined mounting conditions.

[0053] 4, a solder fillet 31 is formed between the second electrode 22 and the current wiring 111, and the resistor 1 is mounted on the substrate 101. As an example, when the solder paste is printed with a printing thickness of 0.1 mm or less, a solder joint layer of 0.05 mm or less can be formed after melting and solidification.

[0054] 3, the first electrode 21 of the resistor 1 is connected to the other current wiring 112 by a lead wire 121. The resistor 1 is connected to the substrate 101 by wire bonding.

[0055] The first electrode 21 of the resistor 1 is connected to the current detection wiring 113 by a bonding wire 131. Furthermore, the current wiring 111 to which the second electrode 22 of the resistor 1 is connected is connected to the current detection wiring 114 by a bonding wire 132. The current detection wiring 114 may be directly connected to the current wiring 111.

[0056] In the circuit board 100 as described above, the resistor 1 can detect a large current flowing through the circuit.

[0057] [Effects of Mounting the Multilayer Resistor on a Circuit Board] As described above, in the resistor 1 according to this embodiment, the resistive element 11 is made of a nickel-chromium or iron-chromium metal material. Therefore, although the molten solder paste wets and spreads along the end face of the second electrode 22, it is difficult for the end face of the resistive element 11 to become wet.

[0058] Therefore, even if there is variation in the amount of solder paste applied or the dimensions of the connection portion of the current wiring 111, it is possible to prevent the solder fillet from creeping up to the first electrode 21 disposed on the upper surface of the resistor 1. This makes it possible to prevent a short circuit between the first electrode 21 and the second electrode 22 in the resistor 1.

[0059] Furthermore, since the resistor 1 has a low profile, it can be connected to the substrate 101 by wire bonding. This allows the resistor 1 to be connected to the substrate 101 at low cost and with high reliability.

[0060] [Modifications of Resistor] <First Modification> Next, a resistor 2 as a first modification of the present embodiment will be described. Fig. 5 is a cross-sectional view of the resistor 2 according to the first modification.

[0061] In the resistor 2, a metal film 41 of nickel or a nickel-phosphorus alloy is formed on the first electrode 21. From the viewpoint of suitably suppressing electromigration of the first electrode 21, the thickness of the metal film 41 is preferably 5% or more, and more preferably 10% to 20%, of the thickness of the first electrode 21. As an example, the thickness of the metal film 41 can be 5 μm to 20 μm.

[0062] In the resistor 2 according to the first modification, the metal film 41 is formed on the first electrode 21, so that the wear of the first electrode 21 due to the occurrence of so-called electromigration can be suppressed.

[0063] From the viewpoint of suppressing electromigration, it is desirable to form a metal film 41 on the second electrode 22 as well as on the first electrode 21 if no problems arise with solder mounting.

[0064] <Second Modification> FIG. 6 is a perspective view illustrating the structure of a resistor 3 according to a second modification.

[0065] The resistor 3 has a first electrode 21 formed with slits 51 that divide the first electrode 21 into predetermined sections.

[0066] The first electrode 21 is divided into a current applying electrode 211 and a detection electrode 212 by a slit 51. The area of ​​the current applying electrode 211 is larger than the area of ​​the detection electrode 212.

[0067] When the resistor 3 is used to detect a large current of, for example, several hundred amperes, a plurality of bonding wires 61 made of aluminum, which has good conductivity, may be bonded to the first electrode 21. In Fig. 6, the bonding wires 61 are represented by two-dot chain lines.

[0068] For example, in the case of large current applications, aluminum bonding wires 61 with a diameter of 400 μm to 500 μm are used. Therefore, a bonding space of approximately 750 μm square is required. As shown in FIG. 6, since multiple bonding wires 61 may be connected, the current applying electrode 211 is provided with a 750 μm square. ２ ~10mm ２ It is preferable to ensure a connection area of ​​more than 1000mV.

[0069] The current applying electrode 211 has a thickness of 750 μm. ２ ~10mm ２ By ensuring a connection area of ​​more than 10 ...

[0070] Furthermore, in applications for detecting large currents, as in this embodiment, the thinner the thickness T1 of the first electrode 21 located on the upper surface side, the more likely the potential distribution in the first electrode 21 is to be affected by the bonding wire, which will cause changes in the current extracted from the first electrode 21 and is expected to lead to a decrease in current detection accuracy.

[0071] In contrast, with the resistor 3, the detection electrode 212 defined by the slit 51 in the first electrode 21 can be connected to the current detection wiring by the bonding wire 61. This allows current to be detected at a position that is not affected by the potential distribution of the bonding wire 61 in the first electrode 21. This improves the accuracy of current detection.

[0072] <Third Modification> Fig. 7 is a perspective view illustrating the structure of a resistor 4 according to a third modification. As in Fig. 6, in Fig. 7, bonding wires 61 are indicated by two-dot chain lines.

[0073] In the resistor 4, a slit 51 is formed to divide the first electrode 21 into a current application electrode 211 and a detection electrode 212, and the detection electrode 212 is further formed with a slit 52 to divide it into a first detection electrode 212A and a second detection electrode 212B.

[0074] In the resistor 4, the first detection electrode 212A or the second detection electrode 212B, which is separated from the current application electrode 211, can be connected to the current detection wiring by a bonding wire 61, thereby avoiding the influence of potential distribution and other disturbances and further improving the accuracy of current detection.

[0075] [Other Embodiments] The present embodiment has been described above, but the above embodiment merely shows one application example of the present invention, and is not intended to limit the technical scope of the present invention to the specific configuration of the above embodiment.

[0076] The resistor 1 in this embodiment may be in the shape of a plate, such as a disk, a square, or a rectangular shape.

[0077] In addition to plating, methods for forming the first electrode 21 and the second electrode 22 on both sides of the resistor 11 may also be used, such as vacuum deposition, ion plating, sputtering, vapor phase growth, cold spraying, thermal diffusion bonding, etc.

[0078] The resistor 11 (first plane 11A) may have a base electrode layer. Similarly, the resistor 11 may have a second plane 11B also having a base electrode layer.

[0079] As an example of a material that can be used to form the base electrode layer, nickel (Ni), a nickel-chromium alloy, or the like, which has a high affinity with the resistor, can be used.

[0080] Furthermore, a strike-plated layer may be formed between the base electrode layer and the resistor 11. Nickel, titanium, silver, etc. may be used as a material for forming the strike-plated layer.

[0081] By forming the base electrode layer and the strike plating layer, the metallic activity of the metal body on the surface of the resistor 11 can be increased.

[0082] A test specimen based on the resistor 1 according to the embodiment of the present invention was fabricated, and various measurements were performed to evaluate the resistor 1. A method for fabricating the test specimen and its evaluation will be described below.

[0083] [Preparation of Test Specimen] <Resistor Material> The resistor material 11a was rolled to a required thickness, and then heat-treated under appropriate conditions suited to each material.

[0084] [Manufacturing of Resistor] Next, a 0.03 mm thick metal layer that would become the first electrode 21 was formed on the first flat surface of the resistor 11a. A 0.10 mm thick metal layer that would become the second electrode 22 was formed on the second flat surface. The first electrode 21 and the second electrode 22 were formed on the surface of the resistor 11 using a plating solution for electrode formation. After the electrode layers were formed, a chip resistor 1 measuring 5 mm x 5 mm square and 1.0 mm thick was fabricated using a dicing blade.

[0085] [Method of mounting to a circuit board] A solder paste was printed to a thickness of 0.1 mm at a predetermined location on a circuit board made of an insulating material and having current wiring formed thereon, and a resistor was then placed on the printed circuit board. The solder was heated to melt and then solidified, and the resistor was connected to the circuit board. The thickness of the solder joint layer after melting and solidification was 0.05 mm.

[0086] [Evaluation Method] The solder wetting evaluation was performed by visually inspecting the side surface of the resistor after solder mounting. The evaluation samples were prepared by printing a solder paste to a thickness of 0.1 mm on a board pattern, placing the resistor, and then reflow mounting.

[0087] [Example] Resistors were fabricated as test specimens under the following conditions. Example 1 First electrode: Cu electrode 0.1 mm Second electrode: Cu electrode 0.1 mm Resistor: nickel-chromium metal 0.8 mm Resistor thickness / lower electrode thickness=8 times Example 2 First electrode: Cu electrode 0.1 mm Second electrode: Cu electrode 0.1 mm Resistor: nickel-chromium metal 0.3 mm Resistor thickness / lower electrode thickness=3 times Comparative Example 1 First electrode: Cu electrode 0.1 mm Second electrode: Cu electrode 0.1 mm Resistor: manganin 0.5 mm Resistor thickness / lower electrode thickness=5 times Comparative Example 2 First electrode: Cu electrode 0.1 mm Second electrode: Cu electrode 0.1 mm Resistor: nickel-chromium metal 0.2 mm Resistor thickness / lower electrode thickness=2 times Comparative Example 3 First electrode: Cu electrode 0.1 mm Second electrode: Cu electrode 0.2 mm Resistor: nickel-chromium metal 1.8mm Resistor thickness / lower electrode thickness = 9 times

[0088] [Results] It was confirmed that solder wetting occurred in the resistor element after reflow mounting in the resistor of Comparative Example 1. In addition, solder wetting occurred in the resistor of Comparative Example 2 depending on the reflow mounting conditions. In addition, the resistor of Comparative Example 3 was found to be resistant to solder wetting, but the product height of the resistor exceeded 2.0 mm, making wire bonding difficult.

[0089] In the resistors of Examples 1 and 2, both the first electrode and the second electrode are formed to 0.1 mm, and the thickness of the resistor is formed to be eight or three times the thickness of the second electrode. Even though the resistor has a low overall height of 1 mm, there is no wetting of the solder onto the resistor when it is mounted on a circuit board.

[0090] Therefore, it was found that the embodiment can realize a multilayer resistor that is low in height and can suppress short circuits caused by solder wetting.

[0091] REFERENCE SIGNS LIST 1 resistor 11 resistive element 11a resistive material 11A first plane 11B second plane 21 first electrode 22 second electrode 211 current application electrode 212 detection electrode 212A first detection electrode 212B second detection electrode 30 solder paste 31 solder fillet 41 metal film 51 slit 52 slit 61 bonding wire 100 circuit board 101 substrate 111, 112 current wiring 113, 114 current detection wiring 121 lead wire 131, 132 bonding wire

Claims

1. A multilayer resistor having a thin plate-shaped resistive element having a first plane and a second plane in the thickness direction, a first electrode formed on the first plane, and a second electrode formed on the second plane, wherein the resistive element contains a nickel-chromium or iron-chromium metallic material, the second electrode faces a circuit pattern formed on the surface of the circuit board when mounted on the circuit board, and the thickness of the resistive element is between three and eight times the thickness of the second electrode.

2. A multilayer resistor according to claim 1, wherein the total thickness of said multilayer resistor is 2 mm or less.

3. A multilayer resistor according to claim 1 or 2, wherein the thickness of the second electrode is 0.1 mm or more and 0.15 mm or less.

4. A multilayer resistor according to claim 1 or 2, wherein the first electrode is thinner than the second electrode.

5. A multilayer resistor according to claim 1, wherein a metal film of nickel or nickel-phosphorus alloy is formed on the first electrode.

6. The multilayer resistor according to claim 1, wherein the multilayer resistor and the circuit board are connected by wire bonding.

7. A multilayer resistor according to claim 6, wherein said first electrode is formed with slits that divide said first electrode into predetermined sections.

8. A multilayer resistor according to claim 7, wherein the first electrode is divided by the slit into a current applying electrode and a detection electrode, and the area of ​​the current applying electrode is larger than the area of ​​the detection electrode.

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