Double-sided alloy foil current-sensing resistor and manufacturing method

Abstract

A double-sided alloy foil current-sensing resistor and a manufacturing method. The double-sided alloy foil current-sensing resistor comprises a first alloy foil resistor body covering the upper surface of a substrate and a second alloy foil resistor body covering the lower surface of the substrate, which form a parallel structure. In the technical solution, the alloy foil resistor can achieve an ultralow resistance value without changing the material, and the resistance value thereof can be reduced to half that of a conventional alloy foil resistor of the same size, thereby solving the problem that common materials used in the prior art cannot achieve ultralow resistance values. Secondly, the alloy foils are adhered to both sides of the ceramic substrate, such that the heat dissipation surface area is doubled under the same volume condition, and convection and heat exchange with air in the surrounding environment are formed to the maximum extent, thereby reducing the product temperature and increasing the rated power and other properties of the product. Finally, adhering the alloy foil resistor bodies to the upper and lower surfaces of the ceramic substrate can solve the problem that in conventional ceramic substrates with single-sided adhered alloy foil resistor bodies, the difference in thermal expansion coefficients causes substrate warping and affects the manufacturing process.

Description

Double-sided alloy foil current detection resistor and preparation method Technical Field

[0001] The present invention relates to an alloy current detection resistor, in particular to a chip-type mounted current detection resistor, in particular to an alloy foil type current detection resistor. Background Art

[0002] Resistors are commonly used electronic devices in the field of electronic circuit technology. For example, a flat resistor structure with a patch structure, such as the resistor with publication number CN112071541A, adopts a substrate, electrodes located at both ends of the substrate, and a resistor layer structure covering one surface of the substrate.

[0003] The problems with chip resistors in the existing technology are: 1. Since increasing the power of the resistor requires reducing the temperature of the resistor during use, the heat dissipation effect of the above-mentioned resistors is poor, which affects the power increase; 2. Given the high-precision requirements of current smart products, the trend is towards lower resistance values. When using commonly used resistor materials, the resistance value is difficult to reduce, and using low-resistance materials as resistors often leads to increased costs; 3. The resistor layer structure is attached to one side of the substrate, and the substrate bends due to differences in thermal expansion coefficients, affecting the process technology.

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

[0005] Summary of the Invention

[0006] In view of the above problems, the purpose of the present invention is to provide a double-sided alloy foil current detection resistor, which can reduce the temperature of the detection resistor during use, thereby improving the product power; and at the same time avoid substrate bending.

[0007] To achieve the above-mentioned target functions, the alloy foil current detection resistor of the present invention can adopt the following technical solutions:

[0008] A double-sided alloy foil current detection resistor includes a substrate and electrodes located at both ends of the substrate, as well as a first alloy foil resistor covering the upper surface of the substrate and a second alloy foil resistor covering the lower surface of the substrate. The first alloy foil resistor and the second alloy foil resistor are electrically connected to the electrodes at both ends to form a parallel structure.

[0009] Furthermore, the first alloy foil resistor and the second alloy foil resistor are made of at least one of manganese copper, copper manganese tin, nickel chromium aluminum silicon, copper manganese nickel or iron chromium alloy.

[0010] Furthermore, the material thickness of the first alloy foil resistor and the second alloy foil resistor are both 0.01-0.1 mm.

[0011] Furthermore, outer surfaces of the first resistor and the second resistor are both covered with a protective layer.

[0012] Furthermore, the electrode is an electroplated copper electrode, and the electrode is also plated with an electroplated nickel layer and a tin layer.

[0013] Beneficial effect: In the technical solution provided by the present invention, the use of double-sided alloy foil resistors in parallel can reduce the overall resistance by 1 time, so that the resistance meets the market application requirements. Secondly, the power increase of the current detection resistor is mainly determined by the heat dissipation capacity of the product, and the heat dissipation capacity is mainly determined by the heat dissipation surface area of ​​the product. The alloy foil resistors on the upper and lower surfaces of the present invention can both dissipate heat, which can increase the heat dissipation area by 1 time compared to the single-sided resistors in the prior art, and can well solve the heat dissipation problem of the current detection resistor, thereby achieving the effect of increasing the power of the product. Finally, the upper and lower surfaces of the ceramic substrate are covered with alloy foil resistors, which solves the problem of the prior art in which the alloy foil resistors are pasted on one side of the substrate, and the substrate bends due to the difference in thermal expansion coefficient, which affects the process technology.

[0014] The present invention also provides a technical solution for a method for preparing the double-sided alloy foil current sensing resistor, comprising the following steps:

[0015] Step 1: treating the surfaces of the first alloy foil resistor and the second alloy foil resistor;

[0016] Step 2: Laminating the first alloy foil resistor and the second alloy foil resistor to the upper and lower surfaces of the substrate respectively;

[0017] Step 3: Etch the resistor pattern on the surface of the alloy foil. The specific speed is adjusted according to the thickness of the material.

[0018] Step 4: Electroplating copper on the upper and lower surface electrodes;

[0019] Step 5: Resistance correction;

[0020] Step 6: Printing protective layer;

[0021] Step 7: Electroplating the electrodes at both ends to connect the upper and lower alloy foils to form a parallel resistor;

[0022] Step 8: Electroplating nickel layer and tin layer.

[0023] Furthermore, the surface treatment parameters in step 1 are: degreasing temperature: 30°C; pickling temperature: 30°C; hot air drying temperature: 70°C; chain speed: 2.5m / min.

[0024] Furthermore, in step 2, the lamination pressure is 5-10 kg / cm 2; Baking temperature: 150-175℃; Baking time: 2-4 hours; Use roller bonding or vacuum bonding to remove air from the bonding surface to complete bonding; In step three, etching temperature: 50℃; Chain speed: 1.5-2.5m / min.

[0025] Furthermore, in step 4, the copper plating thickness is 80-100 um; in step 6, the protective layer thickness is 20-30 um.

[0026] Furthermore, in step seven, the coating thickness is 50-80um; the coating thickness difference is less than 30um; in step eight, nickel 2-4um and tin 5-8um are electroplated from the inside to the outside. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is an overall schematic diagram of a double-sided alloy foil current detection resistor on a ceramic substrate according to the present invention;

[0028] FIG2 is a schematic diagram of a front view and an AA section view of the product of the present invention;

[0029] FIG3 is a schematic diagram of the ceramic substrate in FIG1 of the present invention;

[0030] FIG4 is a schematic diagram of the double-sided alloy foil in FIG1 of the present invention;

[0031] FIG5 is a schematic diagram of the protective layer in FIG1 of the present invention;

[0032] FIG6 is a schematic diagram of electrodes at both ends of FIG1 according to the present invention. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below:

[0034] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0035] Referring to Figures 1 to 6 , this embodiment provides a double-sided ceramic substrate alloy foil current sensing resistor comprising a ceramic substrate 1, upper and lower ceramic alloy foil resistor elements 2, upper and lower alloy foil resistor protective layers 3, and terminal electrodes 4. The alloy foil resistor elements are attached to the upper and lower surfaces of the ceramic substrate using epoxy resin adhesive. Electroplating of the two terminal electrodes connects the alloy foil elements on the upper and lower surfaces of the ceramic substrate to form a parallel resistor. Copper is plated at both ends to form electrodes. Nickel and tin are electroplated on the electroplated copper electrodes to enhance solderability.

[0036] The method for preparing the above-mentioned ceramic substrate double-sided alloy foil current detection resistor comprises the following steps:

[0037] Step 1: Surface treatment of the alloy foil resistor. Degreasing temperature: 30°C. Pickling temperature: 30°C. Hot air drying temperature: 70°C. Chain speed: 2.5 m / min.

[0038] Step 2: Laminating the alloy foil resistor to the ceramic substrate with a lamination pressure of 5-10kg / cm 2 Baking temperature: 150-175°C. Baking time: 2-4 hours. Use roller lamination or vacuum lamination to remove air from the lamination surface to complete the lamination.

[0039] Step 3: Etch the resistor pattern on the alloy foil surface. Etching temperature: 50°C. Chain speed: 1.5-2.5 m / min, depending on the material thickness.

[0040] Step 4: Electroplating copper on the upper and lower surface electrodes: copper thickness 80-100um.

[0041] Step 5: Resistance correction. The resistance accuracy is 0.1%, 0.5%, 1% and can be adjusted based on your needs.

[0042] Step 6: Print the protective layer. Thickness: 20-30um.

[0043] Step 7: Electroplating the electrodes at both ends connects the upper and lower alloy foils, forming a parallel resistor. Plating thickness: 50-80µm. The thickness difference is less than 30µm.

[0044] Step 8: Electroplating nickel layer and tin layer. Electroplating nickel 2-4um and tin 5-8um from the inside to the outside.

Claims

1. A double-sided alloy foil current detection resistor, comprising a substrate and electrodes located at both ends of the substrate, characterized in that, It also includes a first alloy foil resistor covering the upper surface of the substrate and a second alloy foil resistor covering the lower surface of the substrate. The first alloy foil resistor and the second alloy foil resistor are simultaneously electrically connected to the electrodes at both ends to form a parallel structure.

2. The double-sided alloy foil current detection resistor according to claim 1, characterized in that The first alloy foil resistor and the second alloy foil resistor are selected from at least one of manganin, copper-manganese-tin, nickel-chromium-aluminum-silicon, copper-manganese-nickel, or iron-chromium alloy.

3. The double-sided alloy foil current detection resistor according to claim 1 or 2, characterized in that, The material thicknesses of the first alloy foil resistor and the second alloy foil resistor are both 0.01 - 0.1 mm.

4. The double-sided alloy foil current detecting resistor according to claim 3, wherein The outer surfaces of the first resistor and the second resistor are both covered with a protective layer.

5. The double-sided alloy foil current detecting resistor according to claim 3, wherein, The electrodes are electroplated copper electrodes, and an electroplated nickel layer and a tin layer are also plated on the electrodes.

6. A method for preparing a double-sided alloy foil current detection resistor according to any one of claims 1 to 5, characterized in that, It includes the following steps: Step 1, surface treatment of the first alloy foil resistor and the second alloy foil resistor; Step 2: Bond the first alloy foil resistor and the second alloy foil resistor to the upper and lower surfaces of the substrate respectively; Step 3: Etch the resistor pattern on the surface of the alloy foil, and the specific speed is adjusted according to the material thickness; Step 4: Electroplate copper on the upper and lower surfaces of the electrodes; Step 5: Resistance value correction; Step 6: Print the protective layer; Step 7: Electroplate the electrodes at both ends to connect the upper and lower layer alloy foils to form a parallel resistor; Step 8: Electroplate the nickel layer and the tin layer.

7. The preparation method according to claim 6, characterized in that, The surface treatment parameters in Step 1 are: degreasing temperature: 30 °C; pickling temperature: 30 °C; hot air drying temperature: 70 °C; chain speed: 2.5 m / min.

8. The preparation method according to claim 6, wherein In Step 2, the laminating pressure is 5 - 10 kg / cm 2 ; the baking temperature is 150 - 175°C; the baking time is 2 - 4 hours; roller laminating or vacuum laminating is adopted to remove the air inside the laminating surface to complete the lamination; in Step 3, the etching temperature is 50°C; the chain speed is 1.5 - 2.5 m / min.

9. The preparation method according to claim 6, characterized in that In Step 4, the copper plating thickness is 80 - 100 μm; in Step 6, the protective layer thickness is 20 - 30 μm.

10. The preparation method according to claim 6, characterized in that, In Step 7, the coating thickness: 50 - 80 μm; the coating thickness difference is less than 30 μm; in Step 8, nickel 2 - 4 μm and tin 5 - 8 μm are electroplated from the inside outwards.

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