Stacked resistor

Abstract

A laminated resistor which is low in height but inhibits short-circuiting due to solder wettability rise. The laminated resistor is configured to have: a resistor body in a thin plate shape and having a first plane and a second plane in a thickness direction; a first electrode formed on the first plane; and a second electrode formed on the second plane, the resistor body containing a metal material of a nickel-chromium system or an iron-chromium system, the second electrode facing a circuit pattern when mounted to a circuit substrate, and the thickness of the resistor body being 3 times or more and 8 times or less the thickness of the second electrode.

Description

Technical Field

[0001] This invention relates to a stacked resistor for detecting current. Background Technology

[0002] Patent Document 1 discloses a resistor comprising: a resistive body in the shape of a circular plate 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 longitudinal resistor that allows current to flow along a longitudinal direction orthogonal to the substrate.

[0003] The vertical resistor achieves high specific resistance, which, despite its low back resistance, can be applied to high current sensing applications.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-035851 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In vertical resistors, with the advancement of low back contact, the risk of short circuits between the first and second electrodes due to solder used for mounting to the circuit board increases. Therefore, countermeasures are needed to address short circuits caused by increased solder wetting.

[0009] Therefore, the object of the present invention is a stacked resistor that, although low-profile, suppresses short circuits caused by solder wetting.

[0010] Technical means to solve the problem

[0011] According to one aspect of the present invention, a stacked resistor is provided, comprising: a resistive body in the form of a thin plate 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. In the stacked resistor, the resistive body comprises a nickel-chromium or iron-chromium metal material, and the second electrode faces a circuit pattern formed on the surface of the circuit substrate when mounted to a circuit board. The thickness of the resistive body is more than 3 times and less than 8 times the thickness of the second electrode.

[0012] The effects of the invention

[0013] According to one aspect of the present invention, there is a stacked resistor that, although low-profile, can suppress short circuits caused by solder wetting and rising. Attached Figure Description

[0014] [ Figure 1 ] Figure 1 This is a perspective view illustrating the structure of the stacked resistor in this embodiment.

[0015] [ Figure 2 ] Figure 2 It is along Figure 1 A cross-sectional view of the stacked resistors of the II-II line.

[0016] [ Figure 3 ] Figure 3 This is a cross-sectional view of the first modified example of the stacked resistor.

[0017] [ Figure 4 ] Figure 4 This is a perspective view illustrating the stacked resistor structure of the second variation.

[0018] [ Figure 5 ] Figure 5 This is a perspective view illustrating the structure of the stacked resistor in the third variation.

[0019] [ Figure 6 ] Figure 6 This is a three-dimensional diagram illustrating the resistor structure of the second modified example.

[0020] [ Figure 7 ] Figure 7 This is a three-dimensional diagram illustrating the resistor structure of the third modified example. Detailed Implementation

[0021] [Layered Resistors]

[0022] The structure of the stacked resistor 1 in this embodiment will be described with reference to the accompanying drawings.

[0023] The multilayer resistor 1 is a resistor used for current sensing and is called a current sensing resistor or shunt resistor. The multilayer resistor 1 is, for example, mounted in a power module for high current sensing applications.

[0024] Figure 1 This is a perspective view illustrating the structure of the stacked resistor 1 (hereinafter referred to as resistor 1) of this embodiment. Figure 2 It is along Figure 1 A cross-sectional view of resistor 1 on line II-II.

[0025] In this embodiment, the resistor 1 is formed as a thin plate and includes: a resistive body 11 containing resistive material, and a first electrode 21 and a second electrode 22.

[0026] The resistive element 11 has a first plane 11A and a second plane 11B in the thickness direction. A first electrode 21 is formed in the first plane 11A. A second electrode 22 is formed in the second plane 11B.

[0027] That is, resistor 1 has a stacked structure consisting of a first electrode 21, a resistive element 11, and a second electrode 22 stacked in that order.

[0028] In the resistor element 11 of the resistor 1 in this embodiment, along Figure 1 and Figure 2 The thickness direction D (stack direction) shown forms a current path. Therefore, the current path is shorter compared to that of a typical shunt resistor. In resistor 1, to achieve miniaturization, and especially to achieve thinning (low backlighting) in the stack direction, the thickness d of resistor 1 is made thin.

[0029] In this embodiment, from the viewpoint of making the resistor 1 thinner, the overall thickness d of the resistor 1 is preferably 2 mm or less.

[0030] Furthermore, when the resistor 1 is connected to the circuit board by wire bonding, the overall thickness d of the resistor 1 is more preferably 1 mm or less.

[0031] <Electrode>

[0032] The first electrode 21 and the second electrode 22 are electrodes used to allow current to flow along the thickness direction D of the resistive body 11. The first electrode 21 and the second electrode 22 are typically formed using a metallic material suitable for forming electrodes. In this embodiment, a metallic material with high conductivity is used. Copper (Cu) is preferably used as an example of such a metallic material.

[0033] In this embodiment, when the first electrode 21 is mounted to the circuit board, it is located on the upper surface side, which is higher than the surface of the circuit board. When the second electrode 22 is mounted to the circuit board, it faces the circuit pattern formed on the surface of the circuit board.

[0034] 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.

[0035] If the first electrode 21 is thinner than 0.01 mm, the resistance characteristics of resistor 1 will easily change depending on the bonding position of the wire bonding due to the potential distribution in the first electrode 21, resulting in a decrease in detection accuracy. In addition, by making the thickness T1 of the first electrode 21 not exceed 0.07 mm, it can function as a thin plate electrode of resistor 1, and at the same time, it can help to reduce the backlight of resistor 1.

[0036] From the viewpoint of maintaining its function as an electrode for the vertical resistor 1, the thickness T1 of the first electrode 21 is more preferably 0.01 mm to 0.03 mm. More preferably, the thickness T1 of the first electrode 21 is 0.03 mm.

[0037] Furthermore, from the viewpoint of low back exposure, the first electrode 21 can be made thinner than the second electrode 22. In this case, without affecting the resistive characteristics of the resistor 1, 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.

[0038] In this embodiment, from the viewpoint of forming good solder fillet when mounting resistor 1 to circuit board, the thickness T2 of second electrode 22 is preferably 0.1 mm or more and 0.15 mm or less.

[0039] Furthermore, in this embodiment, in order to form a thin electrode with low resistivity, electrode formation by plating is effective, for example. Plating can achieve a resistivity equivalent to that of a metal monomer or a so-called bulk metal.

[0040] Furthermore, by means of plating, the first electrode 21 and the second electrode 22, which are difficult to manufacture by means of bonding bulk metal bodies to a resistive body by means of welding or other methods, can be formed.

[0041] In this embodiment, as an example, from the viewpoint of good electrical conductivity and low resistance of the resistor 1, it is preferable to form a first electrode 21 and a second electrode 22 including copper plating by using copper as the metal material.

[0042] <Resistors>

[0043] The resistor element 11 uses a resistive material with high resistivity and resistance to solder wetting. In this embodiment, nickel-chromium based metals (Ni-Cr alloys) or iron-chromium based metals (Fe-Cr alloys) can be used as such resistive materials. Alternatively, nickel-chromium alloys can also be used that are mainly composed of Ni-Cr or Fe-Cr alloys. As a Ni-Cr alloy, in addition to metals consisting only of Ni and Cr, one or more metals selected from Mo, Al, Si, Mn, Cu, etc. can be added. As an Fe-Cr alloy, in addition to metals consisting only of Fe and Cr, one or more metals selected from Mo, Al, Si, Mn, Cu, etc. can be added.

[0044] Fe-Cr alloys possess higher resistivity than Ni-Cr alloys and are less susceptible to solder wetting, while also exhibiting magnetic properties. Therefore, from the viewpoint of ensuring stable current sensing accuracy and / or voltage sensing accuracy of resistor 1 in environments susceptible to temperature and magnetic field influences, the application of Ni-Cr alloys is more preferable.

[0045] In this embodiment, the thickness h of the resistor 11 is 3 to 8 times the thickness T2 of the second electrode 22. If the thickness h of the resistor 11 is less than 3 times the thickness T2 of the second electrode 22, a good solder fillet cannot be formed, and the bonding strength cannot be ensured. In addition, if the thickness h of the resistor 11 exceeds 8 times the thickness T2 of the second electrode 22, the overall thickness d of the resistor 1 increases, hindering the reduction of backlighting.

[0046] In this embodiment, in order to ensure that the overall thickness d of the resistor 1 does not exceed 2 mm and to reduce the self-inductance of the resistor 1, the thickness h of the resistor body 11 is preferably set to 0.3 mm to 0.8 mm.

[0047] The specific resistance (volume resistance value) of the resistor 11 in this embodiment needs to be set to a value greater than that of the alloy monomer used as the resistive material of a general shunt resistor, which is about 50 μΩ·cm to 100 μΩ·cm.

[0048] Furthermore, in this embodiment, to facilitate mounting to circuit patterns or power semiconductors on a circuit board, 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, as an example, the length R of one side of the resistor 11 can be set to 3 mm to 6 mm. Furthermore, Figure 1 The structure of resistor 1, which is quadrilateral in shape, is shown as an example. The top view of resistor 1 can be rectangular, square, polygonal, circular, etc.

[0049] The resistive material 11a constituting the resistive body 11 is required to be a resistive material whose specific resistance can be designed in the range of 130 μΩ·cm to 200 μΩ·cm.

[0050] In this embodiment, the specific resistance of the resistor 11 is preferably set in the range of 130 μΩ·cm to 150 μΩ·cm. Therefore, even if the distance between the electrodes is designed to be short, i.e., the thickness of the resistor 1 is designed to be thin, in order to reduce the product height, the required resistance value of the resistor 1 as a resistor for high current detection can be achieved.

[0051] Solder

[0052] The solder used in this embodiment is preferably a flux that does not have strong reducing power, such as a Zn-based flux.

[0053] [Effects]

[0054] The resistor 1 in this embodiment is a thin plate-shaped shunt resistor, which has: a resistive body 11 having a first plane 11A and a second plane 11B in the thickness direction D; a first electrode 21 formed in the first plane 11A; and a second electrode 22 formed in the second plane 11B.

[0055] In this embodiment, the first electrode 21 is configured to be located on the upper surface side, which is higher than the surface of the circuit board, when mounted to the circuit board, and the second electrode 22 is configured to face the circuit pattern formed on the surface of the circuit board when mounted to the circuit board.

[0056] In this embodiment, the resistor 11 containing materials such as nickel-chromium metal materials (Ni-Cr alloys) or iron-chromium metal materials (Fe-Cr alloys), or materials containing alloys with Ni-Cr alloys or Fe-Cr alloys as the main components, has the property of being resistant to solder wetting, especially when a Zn-based flux with strong reducing properties is not used.

[0057] Therefore, although resistor 1 is thin plate, the solder is difficult to wet and transfer to the first electrode 21 located on the upper surface side of resistor 1, thus suppressing the occurrence of short circuits caused by the solder rounded corners contacting the first electrode 21.

[0058] Furthermore, in the resistor 1 of this embodiment, the thickness d of the resistor body 11 is more than 3 times and less than 8 times the thickness T2 of the second electrode 22, and the second electrode 22 is configured to face the circuit pattern formed on the surface of the circuit board when mounted to the circuit board.

[0059] Therefore, while achieving a low backing of resistor 1, when mounting resistor 1 onto the circuit board, the effect of suppressing solder from wetting and transferring from the well-formed solder fillet to the first electrode 21 located higher than the resistor body 11 can be improved.

[0060] Therefore, the effect of suppressing short circuits caused by solder fillet contact with the upper first electrode 21 can be further improved.

[0061] In this embodiment, by making the thickness of the second electrode 22 0.1 mm or more and 0.15 mm or less, when the resistor 1 is mounted to the circuit board, it can be ensured that there is a solder fillet with sufficient strength to bond the second electrode 22 to the circuit board.

[0062] When the first electrode 21 is thinner than the second electrode 22, the thickness of the first electrode 21 is 0.1 to 0.5 times the thickness of the second electrode 22, which is 0.01 mm to 0.075 mm, and can be further set to 0.01 mm to 0.03 mm. Thus, while maintaining its function as an electrode for the vertical resistor 1, even with a thickness of the second electrode 22 that allows for the formation of good solder fillet radius, a low-profile resistor 1 can be achieved.

[0063] In this embodiment, by using a resistor 11 with a thickness h of 0.3 mm to 1.2 mm, as well as the first electrode 21 and the second electrode 22, the self-inductance of the resistor 1 can be reduced, and the overall thickness d of the resistor 1 can be less than 2 mm.

[0064] By ensuring that the overall thickness d of resistor 1 is less than 2 mm, the back thickness of resistor 1 can be reduced.

[0065] [Example of mounting to a circuit board]

[0066] Figure 3 This is a schematic diagram illustrating an example of a circuit board 100 on which a resistor 1 is mounted. Figure 4 This is a schematic diagram showing an enlarged view of the main part of resistor 1 in circuit board 100.

[0067] Figure 3 The circuit board 100 shown is, for example, a power module that processes high voltage and high current. In this embodiment, resistor 1 is mounted on the circuit board 100 and functions as a current sensing resistor for detecting high current.

[0068] The circuit board 100 has a substrate 101 containing insulating material, on which current wiring 111 and current wiring 112 constituting a circuit are formed. In addition, current detection wiring 113 and current detection wiring 114 connected to an integrated circuit (IC) for current detection are formed.

[0069] like Figure 3 As shown, resistor 1 is mounted on a designated location in current wiring 111 by soldering. An example of soldering resistor 1 will be described.

[0070] First, solder paste 30 is printed at the designated location of the current wiring 111. Then, with the second electrode 22 of the resistor 1 mounted on the solder paste 30 printed at the designated location of the current wiring 111, it is melted and cured under the specified mounting conditions.

[0071] Therefore, as Figure 4As shown, a solder fillet 31 is formed between the second electrode 22 and the current wiring 111, and the resistor 1 is mounted to the substrate 101. As an example, when the solder paste is printed with a printing thickness of less than 0.1 mm, a solder bonding layer of less than 0.05 mm can be formed after melting and solidification.

[0072] like Figure 3 As shown, the first electrode 21 of resistor 1 is connected to another current wiring 112 via lead 121. Resistor 1 is connected to substrate 101 via wire bonding.

[0073] The first electrode 21 of resistor 1 is connected to the current sensing wiring 113 via connection wire 131. Furthermore, the current wiring 111, to which the second electrode 22 of resistor 1 is connected, is connected to the current sensing wiring 114 via connection wire 132. The current sensing wiring 114 can also be directly wired to the current wiring 111.

[0074] In the circuit board 100 described above, resistor 1 can detect large currents flowing through the circuit.

[0075] [Effect of mounting multilayer resistors onto a circuit board]

[0076] As described above, in the resistor 1 of this embodiment, since the resistor body 11 contains a nickel-chromium or iron-chromium metal material, although the molten solder paste will wet and transfer to the end face of the second electrode 22, the end face of the resistor body 11 is difficult to wet.

[0077] Therefore, even if there are deviations in the amount of solder paste applied or the dimensions of the connection points in the current wiring 111, the solder fillet can be prevented from creeping up to the first electrode 21 disposed on the upper surface of the resistor 1. Thus, short circuits between the first electrode 21 and the second electrode 22 can be suppressed in the resistor 1.

[0078] Furthermore, since resistor 1 achieves low backing, it can be connected to substrate 101 via wire bonding. Thus, resistor 1 can be connected to substrate 101 at low cost and with high reliability.

[0079] [Example of a resistor variation]

[0080] <First Variation>

[0081] Next, the resistor 2, which is the first variation of this embodiment, will be described. Figure 5 This is a cross-sectional view of resistor 2 in the first modified example.

[0082] Resistor 2 has a nickel or nickel-phosphorus alloy metal film 41 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 of the thickness of the first electrode 21, more preferably 10% to 20%. As an example, the thickness of the metal film 41 can be set to 5 μm to 20 μm.

[0083] According to the resistor 2 of the first modification, by forming a metal film 41 on the first electrode 21, the loss of the first electrode 21 due to so-called electromigration can be suppressed.

[0084] From the perspective of suppressing electromigration, it is ideal to form a metal film 41 on the second electrode 22, just like on the first electrode 21, without causing problems with solder mounting.

[0085] <Second Variation>

[0086] Figure 6 This is a perspective view illustrating the structure of resistor 3 in the second modified example.

[0087] The resistor 3 has a slit 51 formed on the first electrode 21, which divides the first electrode 21 into a predetermined partition.

[0088] The first electrode 21 is divided into a current application electrode 211 and a detection electrode 212 by a slit 51. The area of ​​the current application electrode 211 is larger than the area of ​​the detection electrode 212.

[0089] In applications where resistor 3 is used for sensing large currents of hundreds of amperes, multiple highly conductive aluminum bonding wires 61 are sometimes joined to the first electrode 21. Figure 6 The junction line 61 is represented by a double-dotted line.

[0090] As an example, in handling high 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. Figure 6 As shown, since multiple bonding lines 61 may sometimes be connected, it is preferable to ensure a current application electrode 211 of 750 μm. 2 ~ Over 10 mm 2 The connection area.

[0091] 750 μm is ensured by applying current to electrode 211. 2 ~ Over 10 mm 2 The connection area ensures good bonding strength between resistor 3 and circuit board 100.

[0092] Furthermore, in applications involving high current detection, as in this embodiment, the thinner the thickness T1 of the first electrode 21 located on the upper surface side, the more easily the potential distribution in the first electrode 21 is affected by the bonding wire, and the current taken from the first electrode 21 will also change, which is expected to lead to a decrease in the accuracy of current detection.

[0093] To address this, according to resistor 3, the detection electrode 212, defined by slit 51 in the first electrode 21, can be connected to the current detection wiring via bonding wire 61. This allows current to be detected at a location in the first electrode 21 unaffected by the potential distribution caused by bonding wire 61. Therefore, the accuracy of current detection can be improved.

[0094] <Third Variation>

[0095] Figure 7 This is a perspective view illustrating the structure of resistor 4 in the third modified example. Figure 6 Similarly, Figure 7 The junction line 61 is represented by a double-dotted line.

[0096] In resistor 4, a slit 51 is formed that divides the first electrode 21 into a current application electrode 211 and a detection electrode 212. A slit 52 is further formed in the detection electrode 212 that divides it into a first detection electrode 212A and a second detection electrode 212B.

[0097] In resistor 4, since the current application electrode 211 can be connected to the first detection electrode 212A or the second detection electrode 212B and the current detection wiring through the connection line 61, the influence of potential distribution or other interference can be avoided, and the current detection accuracy can be further improved.

[0098] [Other Implementation Forms]

[0099] The above description illustrates this embodiment, but the embodiment only shows one application example of the present invention and is not intended to limit the technical scope of the present invention to the specific structure of the embodiment.

[0100] In this embodiment, resistor 1 can be plate-shaped, and can be round plate-shaped, square corner-shaped, or rectangular corner-shaped.

[0101] In addition to plating, vacuum evaporation, ion plating, sputtering, vapor phase growth, cold spraying, thermal diffusion bonding, etc., can also be used as methods to form the first electrode 21 and the second electrode 22 on both sides of the resistor 11.

[0102] A base electrode layer may be included in the resistive element 11 (first plane 11A). Similarly, a base electrode layer may also be included in the second plane 11B of the resistive element 11.

[0103] As a material constituting the base electrode layer, nickel (Ni) and nickel-chromium alloys, which have a high affinity for resistive materials, can be used, for example.

[0104] Furthermore, an impact plating layer can be formed between the base electrode layer and the resistor 11. Nickel, titanium, silver, etc., can be used as materials for forming the impact plating layer.

[0105] The metal activity of the metal body on the surface of the resistor 11 can be improved by forming a base electrode layer or an impact plating layer.

[0106] [Example]

[0107] A test specimen of resistor 1 based on an embodiment of the present invention was prepared, and various measurements were performed to evaluate resistor 1. The method for preparing the test specimen and its evaluation are described below.

[0108] [Preparation of test subjects]

[0109] <Resistive Materials>

[0110] The resistive material 11a is rolled to achieve the required thickness and then heat-treated under appropriate conditions for each material.

[0111] [Resistor Manufacturing]

[0112] Next, a metal layer with a thickness of 0.03 mm, serving as the first electrode 21, is formed on the first plane of the resistor 11a. Furthermore, a metal layer with a thickness of 0.10 mm, serving as the second electrode 22, is formed on the second plane. Using an electrode forming plating solution, the first electrode 21 and the second electrode 22 are formed on the surface of the resistor 11. After forming the electrode layers, a 5 mm × 5 mm square chip resistor 1 with a thickness of 1.0 mm is fabricated using a cutting tool.

[0113] [Mounting method for circuit board]

[0114] Solder paste is printed to a specified location on a circuit board containing insulating material and in which current wiring is formed, with a thickness of 0.1 mm, and a resistor is then placed thereon. The molten solder is heated and allowed to solidify, after which the resistor is connected to the circuit board. The thickness of the molten and solidified solder joint layer is 0.05 mm.

[0115] [Evaluation Method]

[0116] The solder wetting rise evaluation method utilizes visual inspection to confirm the side surface condition of the resistor after solder mounting. The evaluation sample is prepared by printing solder paste to a substrate pattern at a thickness of 0.1 mm, configuring the resistor, and then reflow soldering it.

[0117] [Example]

[0118] A resistor was fabricated as a test subject under the following conditions.

[0119] <Example 1>

[0120] First electrode: Cu electrode, 0.1 mm

[0121] Second electrode: Cu electrode, 0.1 mm

[0122] Resistor: Nickel-chromium metal, 0.8 mm

[0123] Resistor thickness / lower electrode thickness = 8 times

[0124] <Example 2>

[0125] First electrode: Cu electrode, 0.1 mm

[0126] Second electrode: Cu electrode, 0.1 mm

[0127] Resistor element: 0.3 mm nickel-chromium metal

[0128] Resistor thickness / lower electrode thickness = 3 times

[0129] <Comparative Example 1>

[0130] First electrode: Cu electrode, 0.1 mm

[0131] Second electrode: Cu electrode, 0.1 mm

[0132] Resistor element: 0.5 mm manganese copper

[0133] Resistor thickness / lower electrode thickness = 5 times

[0134] <Comparative Example 2>

[0135] First electrode: Cu electrode, 0.1 mm

[0136] Second electrode: Cu electrode, 0.1 mm

[0137] Resistor element: 0.2 mm nickel-chromium metal

[0138] Resistor thickness / lower electrode thickness = 2 times

[0139] <Comparative Example 3>

[0140] First electrode: Cu electrode, 0.1 mm

[0141] Second electrode: Cu electrode, 0.2 mm

[0142] Resistor element: 1.8 mm nickel-chromium metal

[0143] Resistor thickness / lower electrode thickness = 9 times

[0144] [result]

[0145] In the resistor of Comparative Example 1, solder wetting was confirmed in the resistor element after reflow soldering. Furthermore, in the resistor of Comparative Example 2, solder wetting occurred depending on the reflow soldering conditions. Additionally, in the resistor of Comparative Example 3, although resistance to solder wetting was confirmed, the resistor's product height exceeded 2.0 mm, making wire bonding difficult.

[0146] According to the resistors of Embodiments 1 and 2, even if the first electrode and the second electrode are both formed to be 0.1 mm, and the thickness of the resistive body is formed to be 8 times or 3 times the thickness of the second electrode, and the overall thickness is 1 mm, such a low-back resistor does not experience solder wetting and rising to the resistive body when it is mounted on the circuit board.

[0147] Therefore, as can be seen from the embodiments, a stacked resistor can be realized, which, although low-back, can suppress short circuits caused by solder wetting and rising.

[0148] Explanation of icon numbers

[0149] 1: Resistor

[0150] 11: Resistor

[0151] 11a: Resistive materials

[0152] 11A: First plane

[0153] 11B: Second plane

[0154] 21: First electrode

[0155] 22: Second electrode

[0156] 211: Current-applying electrode

[0157] 212: Electrode for detection

[0158] 212A: First detection electrode

[0159] 212B: Second detection electrode

[0160] 30: Solder paste

[0161] 31: Solder fillet

[0162] 41: Metal film

[0163] 51: Slit

[0164] 52: Slit

[0165] 61: Joint line

[0166] 100: Circuit board

[0167] 101: Substrate

[0168] 111, 112: Current wiring

[0169] 113, 114: Wiring for current detection

[0170] 121: Lead wire

[0171] 131, 132: Joint lines

Claims

1. A stacked resistor, having: A resistive element that is thin and has a first plane and a second plane in the thickness direction; The first electrode formed on the first plane; and The second electrode formed on the second plane, in the stacked resistor, The resistive element comprises a nickel-chromium or iron-chromium metallic material. When the second electrode is mounted to the circuit board, it faces the circuit pattern formed on the surface of the circuit board. The thickness of the resistive element is more than 3 times and less than 8 times the thickness of the second electrode.

2. The stacked resistor according to claim 1, wherein, The overall thickness of the stacked resistor is less than 2 mm.

3. The stacked 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. The stacked resistor according to claim 1 or 2, wherein, The first electrode is thinner than the second electrode.

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

6. The stacked resistor according to claim 1, wherein, The stacked resistor is connected to the circuit board via wire bonding.

7. The stacked resistor according to claim 6, wherein, A slit is formed in the first electrode to divide the first electrode into a specified partition.

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

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