Preparation method of four-terminal resistor and four-terminal resistor

Abstract

The invention discloses a preparation method of a four-terminal resistor and the four-terminal resistor. The preparation method comprises the following steps: applying a layer of photosensitive film on the lower surface of an alloy body, exposing part of the alloy body through exposure, development and etching, and applying a metal layer at the exposed position to serve as an end surface electrode and a voltage acquisition point; wherein the voltage acquisition point is directly connected with the resistance design area of the resistance alloy, the measurement result is closer to the design result, and the earlier-stage design of the product is facilitated; the photosensitive film is applied to the lower surface of the alloy body, part of the alloy body is exposed through exposure, development and etching, the exposed part serves as the application position of the four terminals, products of different specifications can use a unified etching pattern, and production process control is simplified.

Description

Technical Field

[0001] The present invention relates to the technical field of resistors. Background Art

[0002] With the progress of the performance of electronic products and the requirement of precision development, precision resistors are required to have higher precision, smaller resistance values, and higher power tolerance capabilities. However, currently, resistors mainly have a two-terminal structure. After the size is determined, the resistance value design ability of the product is restricted by the limit of the performance parameters of the material and the process ability level of each industry, especially for products with a resistance value of 1 mΩ or less. Taking precision resistors as an example, the relatively commonly used alloy materials currently mainly include copper-manganese-tin, copper-manganese-nickel, Karma, iron-chromium-aluminum, etc. Among them, the material with the lowest resistivity, relatively stable TCR (temperature coefficient of resistance), and can be mass-produced is copper-manganese-tin. Therefore, the product design bottleneck will be determined according to the characteristics of this material, resulting in difficult product design and complex production processes for some ultra-low resistance precision resistors (such as 0.2 mΩ, 0.5 mΩ, etc.). In order to make the resistance value lower, conventional resistors will be achieved by increasing the internal electrode design or complex electrode structures, etc. However, related methods will cause problems such as an increase or uncontrollability of the TCR of the product, a reduction in power, and complex processes.

[0003] In addition, for the four-terminal resistor structure commonly used in the prior art as Figure 1 shown, since this structure is an asymmetric design, the direction and polarity of the product need to be considered during the processing and assembly of the resistor. If the asymmetric structure is processed or assembled in the opposite direction and polarity to the designed direction, the product will be unusable. Therefore, this structure increases the processing and assembly difficulty of the resistor.

[0004] Therefore, a new technical solution is needed to solve the above technical problems. Summary of the Invention

[0005] Aiming at the above problems, the purpose of the present invention is to provide a preparation method capable of obtaining a four-terminal resistor through a relatively simple process.

[0006] The present invention also provides the four-terminal resistor obtained by this preparation method, which solves the problem of the relatively large processing and assembly difficulty of the resistor in the prior art.

[0007] To achieve the above target functions, the preparation method of the four-terminal resistor of the present invention can adopt the following technical solutions:

[0008] A preparation method of a four-terminal resistor, comprising the following steps:

[0009] S1. Provide an alloy body and a substrate, bond the upper surface of the alloy body to the lower surface of the substrate through an adhesive film, and after the adhesive film is cured;

[0010] S2. Cut the resistance alloy and the substrate into sheet materials;

[0011] S3. Apply a photosensitive film on the lower surface of the alloy body, and expose, develop, and etch it to expose part of the alloy body.

[0012] S4. Apply several metal layers to the exposed part of the lower surface of the alloy body.

[0013] S5. Remove the photosensitive film reserved on the lower surface of the alloy body.

[0014] S6. Correct the resistance value of the resistance alloy, and apply the resistance correction area in the middle area between the two voltage acquisition points on the lower surface of the resistance alloy.

[0015] S7. Apply a protective layer on the lower surface of the alloy body, and the protective layer only covers the part of the resistance alloy surface where no metal layer is applied.

[0016] S8. Process the sheet material into multiple granular materials; each granular material includes at least four metal layers, where two metal layers are located at both ends of the granular material as electrode terminals, and the other two metal layers are located between the two electrode terminals as voltage sampling points.

[0017] S9. Cover the electrode terminals and voltage sampling points of the granular material with a metal layer again.

[0018] Beneficial effects: In the technical solution provided by the present invention, the voltage acquisition point is directly connected to the resistance design area of the resistance alloy, and the measurement result is closer to the design result, which is convenient for the preliminary design of the product; a photosensitive film is applied on the lower surface of the alloy body, and part of the alloy body is exposed by exposure, development, and etching. The exposed part is used as the application position of the four terminals, so that different specifications of products can use a unified etching pattern, simplifying the production process control.

[0019] The present invention also provides a technical solution for the four-terminal resistor prepared by the above preparation method:

[0020] A four-terminal resistor prepared by the described preparation method, including a resistance alloy, a substrate carrying the resistance alloy, a glue film located between the resistance alloy and the substrate, end face electrodes located at both ends of the bottom of the resistance alloy, and two voltage sampling points located at the bottom of the resistance alloy. The two voltage sampling points are located between the end face electrodes at both ends; the two voltage sampling points are designed to be centrosymmetric with respect to the center position of the resistance alloy, and the two end face electrodes are also designed to be centrosymmetric with respect to the center position of the resistance alloy.

[0021] Further, the shapes and sizes of the end face electrodes and voltage sampling points are adjustable according to the design.

[0022] Further, the material of the voltage sampling point is copper, gold, silver, nickel, tin or an alloy thereof.

[0023] Further, the distance between adjacent end face electrodes and voltage sampling points is not less than 0.1 mm.

[0024] Further, the matrix material is ceramic, FR4 or polyimide.

[0025] Further, the resistance alloy is at least one of manganin, copper-manganese-tin, nickel-chromium-aluminum-silicon, copper-manganese-nickel, and iron-chromium alloy.

[0026] Further, the lower surface of the resistance alloy is covered by a protective layer; the protective layer is divided into multiple regions by voltage sampling points, and the material of the protective layer is epoxy resin or polyimide.

[0027] Compared with the prior art, the significant advantages of this four-terminal resistor are as follows: the voltage acquisition point and the current input point are completely isolated, avoiding signal acquisition deviation caused by current-voltage signal interference; the voltage acquisition point is close to the middle area of the resistance alloy body, which is conducive to the heat dissipation in this area and improves the operating power of the product; at the same time, the electrode terminals and voltage acquisition points in this solution are designed in central symmetry, and the current density distribution is more uniform, which is conducive to improving the measurement accuracy of the product; the voltage acquisition point is directly connected to the resistance design area of the resistance alloy, and the measurement result is closer to the design result; the voltage acquisition point and the current input point are designed in central symmetry, avoiding the problem of direction identification during processing and assembly. Description of the Drawings

[0028] Figure 1 is a schematic structural diagram of a four-terminal resistor in the prior art;

[0029] Figure 2 is a bottom view of the product structure of an embodiment of the present invention;

[0030] Figure 3 is a side view of the product structure of an embodiment of the present invention;

[0031] Figure 4 is a schematic diagram of process S1 of the present invention;

[0032] Figure 5 is a schematic diagram of process S2 of the present invention;

[0033] Figure 6 is a schematic diagram of process S3 of the present invention;

[0034] Figure 7 is a schematic diagram of process S4 of the present invention;

[0035] Figure 8 is a schematic diagram of process S5 of the present invention;

[0036] Figure 9 is a schematic diagram of process S6 of the present invention;

[0037] Figure 10It is a schematic diagram of process S7 of the present invention;

[0038] Figure 11 It is a schematic diagram of process S8 of the present invention;

[0039] Figure 12 It is a schematic diagram of process S9 of the present invention. Detailed implementation manners

[0040] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0041] Embodiment 1

[0042] Please refer to Figures 4 to 12 As shown, Embodiment 1 provides a method for manufacturing a four-terminal resistor, and the process is as follows:

[0043] S1. The upper surface of the resistor alloy 5 is adhered to the lower surface of the substrate 4 through the adhesive film 6, and it needs to be cured at a high temperature of 110°C to 170°C to complete the curing of the adhesive film 6, as Figure 4 shown.

[0044] S2. The resistor alloy 5 is cut into the product design size by means of laser, blade, etc. to obtain sheet materials, as Figure 5 shown.

[0045] S3. A photosensitive film 7 is applied to the lower surface of the alloy body 5, and a design pattern is formed through exposure, development and etching, as Figure 6 shown.

[0046] S4. For the exposed part of the lower surface of the resistor alloy 5 body, a metal layer is applied by means of sputtering, electroplating, deposition, etc., and this metal layer will serve as the end face electrode 1 and the voltage sampling point 2, as Figure 7 shown.

[0047] S5. The reserved photosensitive film 7 on the lower surface of the resistor alloy 5 body is removed, as Figure 8 shown.

[0048] S6. The resistance value of the product is corrected by means of laser, mechanical, depositing metal, etc., and the resistance correction area 8 is applied to the middle area between the two voltage acquisition points 2 on the lower surface of the resistor alloy 5, as Figure 9 shown.

[0049] S7. A protective layer 3 is applied to the lower surface of the resistor alloy 5 body, and this protective layer 3 covers the resistor body 5 and the resistance correction area 8, and the end face electrode 1 and the voltage sampling point 2 need to be avoided from being covered, as Figure 10 shown.

[0050] S8. The sheet material is processed into granular by means of laser, mechanical, etc., as Figure 11 shown.

[0051] S9. A metal layer is applied to the outermost layer of the end face electrode 1 and the voltage sampling point 2 by means of barrel plating, deposition, coating, etc., such as Figure 12 shown.

[0052] Embodiment 2

[0053] Please refer to Figure 2 and Figure 3 shown. This embodiment is a four-terminal resistor prepared by the preparation method of Embodiment 1. The four-terminal resistor includes an end face electrode 1, a voltage sampling point 2, a protective layer 3, a substrate 4, a resistance alloy 5, and a film adhesive 6. The two end face electrodes 1 are located at both ends of the bottom of the resistance alloy 5. The two voltage sampling points 2 are also located at the bottom of the resistance alloy, and the two voltage sampling points 2 are located between the end face electrodes 1 at both ends. The two voltage sampling points 2 are designed to be centrosymmetric with respect to the central position of the resistance alloy 5, and the two resistance alloys 5 are also designed to be centrosymmetric with respect to the central position of the end face electrode 1. During processing, the direction polarity does not need to be particularly considered. Even if the resistor is rotated 180° during assembly, it can still be assembled and used, avoiding the problem of direction identification during processing and assembly.

[0054] The end face electrode 1 and the voltage acquisition point 2 are made of low-resistance and high-thermal-conductivity metal materials or their alloys such as copper, nickel, tin, silver, and gold; the material of the resistance alloy 5 is one of manganin alloy, nickel-chromium alloy, iron-chromium alloy, and titanium-tungsten alloy. The cross-sectional area of the resistance alloy 5 is reduced by cutting patterns or thinning on the surface of the resistance alloy 5 by means of laser trimming, mechanical methods, etc. to make it reach the preset resistance value. The film adhesive 6 is made of a thermal conductive material with a thickness of 12.5 - 50 um and a thermal conductivity of 3 - 5 w / mk, and the bonding temperature is 160 - 180 °C, and the pressure is 3 - 5 kg / cm 2. .

[0055] The surface of the resistance alloy 5 is covered with a protective layer 3; the space between the electrode 1 and the voltage sampling point 2 is filled with the protection 3 to achieve the purpose of isolation from each other.

[0056] The electrode 1 and the voltage sampling point 2 are composed of a copper layer, a nickel layer, and a tin layer. The thickness of the copper layer is more than 50 um, and the nickel layer and the tin layer are more than 5 um; the copper layer increases the thermal conductivity, the nickel layer serves as a connection layer to increase the bonding force between the copper layer and the tin layer, and the tin layer increases the solderability of the current detection resistor.

[0057] When the current detection resistor is working, the heat generated by the resistance alloy 5 is quickly introduced into the PCB board through the electrode 1 and the voltage sampling point 2, thereby reducing the temperature of the resistance alloy 5 and improving the power and performance of the current detection resistor.

[0058] When the current detection resistor is working, the current path and the voltage path are physically isolated, and the interference of current input and voltage acquisition is reduced, which is beneficial to precise measurement.

Claims

1. A method for preparing a four-terminal resistor, comprising the following steps: S1. Provide an alloy body and a substrate, wherein the upper surface of the alloy body is bonded to the lower surface of the substrate via an adhesive film, and the adhesive film is cured; S2, cutting the resistance alloy and the substrate into sheet materials; S3, applying a layer of photosensitive film on the lower surface of the alloy body, and exposing part of the alloy body by exposure, development and etching; S4, applying a plurality of metal layers to the exposed portion of the lower surface of the alloy body; S5. removing the photosensitive film reserved on the lower surface of the alloy body; S6, correcting the resistance value of the resistance alloy, and applying the resistance correction area to the middle area between the two voltage collection points on the lower surface of the resistance alloy; S7, applying a protective layer on the lower surface of the alloy body, wherein the protective layer only covers the portion of the resistance alloy surface where the metal layer is not applied; S8, processing the sheet material into a plurality of granular materials; each granular material comprises at least four metal layers, wherein two metal layers are located at both ends of the granular material as electrode terminals, and the other two metal layers are located between the two electrode terminals as voltage sampling points; S9. Cover the electrode terminals and voltage sampling points of the granular material with a metal layer.

2. The method for preparing a four-terminal resistor according to claim 1, characterized in that: In S1, the film is cured at 110°C to 170°C.

3. The method for preparing a four-terminal resistor according to claim 1, characterized in that: In S3, several metal layers are applied to the exposed portion of the lower surface of the alloy body by sputtering, electroplating or deposition; in S6, the resistance value of the resistor alloy is corrected by laser, mechanical or metal deposition; in S9, the electrode terminals and voltage sampling points of the granular material are covered with a metal layer by roller plating.

4. A four-terminal resistor obtained by the preparation method according to any one of claims 1 to 3, characterized in that: The invention comprises a resistance alloy (5), a substrate (4) supporting the resistance alloy (5), a film (6) located between the resistance alloy (5) and the substrate (4), end surface electrodes (1) located at two ends of the bottom of the resistance alloy (5), and two voltage sampling points (2) located at the bottom of the resistance alloy (5), wherein the two voltage sampling points (2) are located between the end surface electrodes (1) at two ends; the two voltage sampling points (2) are designed to be centrally symmetrical with respect to the central position of the resistance alloy (5), and the two end surface electrodes (1) are also designed to be centrally symmetrical with respect to the central position of the resistance alloy (5).

5. The four-terminal resistor according to claim 4, characterized in that The shapes and sizes of the end surface electrodes (1) and the voltage sampling points (2) are adjustable according to the design.

6. The four-terminal resistor according to claim 4, characterized in that The voltage sampling point (2) is made of copper, gold, silver, nickel, tin or an alloy thereof.

7. The four-terminal resistor according to claim 4, characterized in that The distance between adjacent end surface electrodes (1) and voltage sampling points (2) is not less than 0.1 mm.

8. The four-terminal resistor according to claim 4, characterized in that The substrate (4) is made of ceramic, FR4 or polyimide.

9. The four-terminal resistor according to claim 4, characterized in that The resistance alloy (5) is at least one of manganese copper, copper manganese tin, nickel chromium aluminum silicon, copper manganese nickel, and iron chromium alloy.

10. The four-terminal resistor according to claim 4, characterized in that The lower surface of the resistance alloy (5) is covered with a protective layer (3); the lower surface of the protective layer (3) is divided into a plurality of areas by the voltage sampling points (2); the material of the protective layer (3) is epoxy resin or polyimide.

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