Ultrathin low-resistance alloy resistor and preparation method thereof

Abstract

The invention discloses an ultrathin low-resistance alloy resistor and a preparation method thereof, and the preparation method comprises the following steps: pasting dry films on the two surfaces of an alloy sheet, and then carrying out exposure and development to form a first circuit pattern on the dry films; etching to form second circuit patterns corresponding to the first circuit patterns on the dry film on the two surfaces of the alloy sheet; removing the film to remove the dry film on the alloy sheet; the alloy sheet is attached to the base material, and a plate is obtained; and performing post-treatment on the plate to obtain the ultrathin low-resistance alloy resistor. According to the preparation method of the ultrathin low-resistance alloy resistor, the lateral erosion amount of a product can be effectively reduced, the stability of the etching resistance value of the product is ensured, under the same etching condition, a double-face etching mode is adopted, the lateral erosion amount of the product is reduced by a half, the time consumed by an etching section is shortened by a half, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy resistors, and particularly relates to a preparation method of an ultra-thin low-resistance alloy resistor (with a resistance value of 1-2 mΩ and a thickness of 0.6±0.1 mm), and an ultra-thin low-resistance alloy resistor prepared by using the preparation method. Background Art

[0002] Low-resistance alloy resistors have high precision and good stability, and mainly play the role of current detection in circuits. Their applications in electronic circuits are becoming more and more extensive, which can ensure the stability and reliability of electronic devices. The existing low-resistance alloy material resistors are mainly prepared by single-sided etching. The product has a large amount of side etching in this preparation method; the preparation methods of stamping and plastic encapsulation have high costs and low efficiency.

[0003] The existing preparation method is basically as follows: After the alloy and the substrate are bonded, single-sided film laminating and exposure and development are carried out, and then a resistor body semi-finished product with a certain resistance value is obtained by single-sided etching. Subsequently, single-chip resistor products are obtained through solder mask, electroplating, cutting, and barrel plating methods.

[0004] For small-size ultra-thin alloy low-resistance resistors, according to the resistance calculation formula: R = ρ*L / S (where R is the resistance value; ρ is the resistivity; L is the length of the resistor body; S is the cross-sectional area of the resistor body), it can be seen that because the width W of the product is fixed, thick alloy materials are required to make low-resistance products. However, in the traditional single-sided etching production process, the thicker the material, the greater the side etching amount of the alloy during etching. A large side etching amount will make it difficult to control the resistance value of the product and easily deviate from the target resistance value; at the same time, burrs will also be formed during subsequent electrode copper plating, affecting the appearance of the product.

[0005] For example, a patent with the application number 2020103301538 discloses a chip resistor, which prepares a miniaturized and low-resistance resistor by laminating a film layer on the bonding surface of the polymer fiber resin film and the resistor body layer. However, the etching method of the resistor body layer in this patent is the traditional single-sided etching method, and there will be a large amount of side etching for the resistor prepared from the alloy material.

[0006] Another example is a patent with the application number 2021100489766, which discloses a method of preparing an upper resistor with a first preset thickness and a lower resistor with a second preset thickness on the resistor body to reduce the resistance value of the resistor without increasing the PCB area. However, the overall thickness of the resistor is synchronously increased in the solution of this patent, and when preparing the lower resistor with a preset thickness, there will be a large amount of side etching if the chemical etching method is used, and the size is also difficult to control.

[0007] For another example, the patent with the international publication number WO 2022 / 205641 A1 directly pastes a heat sink on a resistor alloy sheet through an insulating and heat-conducting layer, and a high-power resistor with good heat dissipation effect can be obtained. However, synchronously adding a heat sink will increase the overall thickness of the resistor, which is not conducive to the thinning of the product. At the same time, the preparation method of this resistor requires pressing and then etching a set pattern first, and there will be a problem of large side etching amount in the alloy single-sided etching method.

[0008] For example, the patent with the application number 201310221963X discloses a manufacturing process for buried resistors. The ultra-thin core board is processed by double-sided etching and one-step lamination to manufacture a buried resistor structure. However, in this patent, the resistor is buried in the PCB board. First, it is laminated, then etched, and then the resistance is detected. It is not suitable for manufacturing single small-size and low-resistance alloy resistors for SMT mounting; the alloy used for low-resistance alloy resistors is relatively thick, and it is necessary to etch first and then laminate to ensure the consistency of the patterns on both sides.

[0009] The disclosure of the above background technical content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this application. Without clear evidence indicating that the above content was publicly available before the filing date of this application, the above background art should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0010] In view of this, in order to overcome the defects of the prior art, the purpose of the present invention is to provide a preparation method for an ultra-thin and low-resistance alloy resistor, which can effectively reduce the side etching amount of the product and ensure the stability of the etched resistance value of the product under the condition of a relatively low overall thickness of the product.

[0011] In order to achieve the above purpose, the present invention adopts the following technical solutions: A preparation method for an ultra-thin and low-resistance alloy resistor includes the following steps: Attach dry film to both sides of the alloy sheet, and then perform exposure and development to form a first circuit pattern on the dry film; Etch to form a second circuit pattern corresponding to the first circuit pattern on the dry film on both sides of the alloy sheet; Strip the film to remove the dry film on the alloy sheet, and at this time, an alloy sheet with a set circuit pattern is obtained; Bond the alloy sheet to a substrate to obtain a sheet; Perform post-treatment on the sheet to obtain the ultra-thin and low-resistance alloy resistor.

[0012] According to some preferred implementation aspects of the present invention, the second circuit patterns on both sides of the alloy sheet are exactly the same. After the etching is completed, the second circuit patterns penetrate through the thickness of the alloy sheet to form corresponding set circuit patterns. That is, during etching, as the etching progresses, the etching depth of the second circuit patterns corresponding to both sides of the alloy sheet gradually increases and finally penetrates through the thickness direction of the alloy sheet, thereby obtaining the set circuit patterns on the alloy sheet and completing the etching.

[0013] According to some preferred implementation aspects of the present invention, during the etching, both sides of the alloy sheet are etched simultaneously and the etching conditions are kept consistent.

[0014] According to some preferred implementation aspects of the present invention, the conditions for the etching are an acidic etching solution, an etching speed of 1 - 3 m / min; an etching temperature of 45 ± 5°C.

[0015] According to some preferred implementation aspects of the present invention, the preparation of the sheet is to set an epoxy resin film between the alloy sheet and the substrate, and then perform pre - lamination first, and then use a vacuum press for vacuum lamination.

[0016] According to some preferred implementation aspects of the present invention, the lamination time for the pre - lamination is 100 - 150 s, the lamination pressure is 20 - 30 KG, and the lamination temperature is 140 - 160°C.

[0017] According to some preferred implementation aspects of the present invention, the lamination time for the vacuum lamination is 280 - 320 s, the lamination pressure is 50 - 70 KG, and the lamination temperature is 140 - 160°C.

[0018] According to some preferred implementation aspects of the present invention, the dry film lamination is to laminate the upper and lower surfaces of the alloy sheet with the dry film using a laminating machine; the lamination time is 55 - 65 s, the lamination pressure is 40 - 50 KG, and the lamination temperature is 130 - 150°C.

[0019] According to some preferred implementation aspects of the present invention, the post - treatment includes primary printing, copper plating, secondary printing, particle separation, and barrel plating performed in sequence.

[0020] According to some preferred implementation aspects of the present invention, the primary printing step is used to print a protective ink to protect the resistor body for subsequent copper plating at the electrode.

[0021] According to some preferred implementation aspects of the present invention, the post - treatment includes a resistor trimming step after copper plating, which is used to trim the resistance value of the alloy resistor to a set resistance value.

[0022] According to some preferred implementation aspects of the present invention, the secondary printing step is used to print the protective ink again and cover the resistor trimming notch.

[0023] According to some preferred implementation aspects of the present invention, the steps include a pretreatment step before laminating the dry film, which is used to remove the oxidized substances and oil stains on the surface of the alloy sheet.

[0024] According to some preferred implementation aspects of the present invention, during the exposure, for the dry films on both sides of the alloy sheet, the same set of optical positioning points are used for alignment, so as to make the second circuit patterns on both sides of the alloy sheet completely correspond, avoid the offset of the second circuit patterns on both sides, and prevent the etching from being unable to penetrate.

[0025] According to some preferred implementation aspects of the present invention, the alloy sheet is formed by cutting the alloy coil; the thickness of the alloy coil and the alloy sheet is 0.3 - 0.4 mm.

[0026] According to some preferred implementation aspects of the present invention, the resistance value of the ultra-thin low-resistance alloy resistor is 1 - 2 mΩ, and the thickness is 0.6 ± 0.1 mm.

[0027] In some embodiments of the present invention, the preparation method of the ultra-thin low-resistance alloy resistor specifically includes the following steps: S1. Cutting The alloy coil is cut into alloy sheets of a set size, and each alloy sheet is subsequently used to form multiple ultra-thin low-resistance alloy resistors.

[0028] S2. Pretreatment The surface of the alloy sheet is pretreated to remove the oxides and oil stains on the surface of the alloy sheet, which is beneficial to the full lamination of the subsequent dry film and the alloy sheet.

[0029] The pretreatment is specifically: the alloy sheet is pretreated with a micro-etching solution to remove the surface oil stains and oxides, the micro-etching speed: 1 - 3 m / min, and the micro-etching temperature: 45 ± 5 °C.

[0030] The micro-etching solution is a mixed solution formed by sulfuric acid and hydrogen peroxide, and the concentration of sulfuric acid in the mixed solution is 5% ± 1%; the concentration of hydrogen peroxide is 5% ± 1%.

[0031] S3. Double-sided film lamination Using a film laminating machine, the upper and lower surfaces of the alloy sheet are fully laminated with the dry film.

[0032] The lamination parameters include a lamination time of 55 - 65 s, a lamination pressure of 40 - 50 KG, and a lamination temperature of 130 - 150 °C.

[0033] S4. Exposure and development The upper and lower surfaces of the alloy sheet laminated with the dry film are exposed, and then developed to obtain the first circuit patterns of a predetermined shape on the dry films on the upper and lower surfaces of the alloy sheet.

[0034] S5. Double-sided etching After the developed alloy sheet is etched, a double-sided synchronous etching method is used during etching, so that the upper and lower surfaces of the alloy sheet simultaneously obtain the second circuit pattern corresponding to the first circuit pattern on the dry film. The etching conditions on the upper and lower surfaces are the same to reduce the side etching amount and improve the etching efficiency.

[0035] Acid etching solution is used for etching, etching speed: 1 - 3 m / min; etching temperature: 45 ± 5 °C. The acid etching solution is a mixed solution formed by copper chloride and hydrochloric acid. The concentration of copper chloride in the mixed solution is 90 - 95%, and the concentration of hydrochloric acid is 5 - 10%.

[0036] Since it is necessary to ensure the complete correspondence of the circuit patterns on the upper and lower surfaces of the alloy sheet, the same set of alignment marks is used on the upper and lower surfaces during graphic exposure in the present invention to ensure the complete correspondence of the first circuit patterns on both sides of the dry film, so that the positions and shapes of the second circuit patterns on both surfaces of the alloy sheet are completely the same, so as to form a through-set circuit pattern in the thickness of the alloy sheet after etching.

[0037] S6. Stripping the film The etched alloy sheet is subjected to film stripping treatment to remove the dry film on the surface of the alloy sheet, and at this time, an alloy sheet with a set circuit pattern is obtained.

[0038] Film stripping speed: 1 - 2 m / min; film stripping temperature: 45 ± 5 °C.

[0039] S7. Laminating the substrate First, an epoxy resin film is set between one surface of the etched alloy sheet and the substrate; then pre-pressing is carried out, and then vacuum pressing is carried out using a vacuum press to obtain a sheet.

[0040] The pressing time for pre-pressing is 100 - 150 s, the pressing pressure is 20 - 30 KG, and the pressing temperature is 140 - 160 °C. The pressing time for vacuum pressing is 280 - 320 s, the pressing pressure is 50 - 70 KG, and the pressing temperature is 140 - 160 °C.

[0041] S8. Post-treatment The post-treatment includes primary printing, copper plating, resist repair, secondary printing, particle separation, and barrel plating carried out in sequence. Specifically as follows: S81. Primary printing The laminated sheet is printed with a protective ink for the first time to protect the alloy resistor body for subsequent copper plating at the electrode.

[0042] S82. Copper plating Copper plating is carried out after the primary printing to make the electrodes of the ultra-thin low-resistance alloy resistor product.

[0043] S83. Resist repair After copper plating, resistance trimming is carried out to make the resistance value of the product reach the set range.

[0044] S84. Secondary printing After resistance trimming, protective ink is printed for the second time to cover the cutting edge of the resistance trimming.

[0045] S85. Granulation When the sheet is used to form multiple ultra-thin low-resistance alloy resistors, after resistance trimming, the semi-finished sheet is cut into grains to form multiple ultra-thin low-resistance alloy resistors.

[0046] In this embodiment, when the sheet is used to form multiple ultra-thin low-resistance alloy resistors, the post-treatment includes the step of granulation. In some other embodiments, if the sheet is only used to form one ultra-thin low-resistance alloy resistor, granulation is not required in the post-treatment.

[0047] S86. Nickel-tin plating Roll plating of nickel-tin is carried out at the corresponding electrodes of the granulated single ultra-thin low-resistance alloy resistor products to obtain ultra-thin low-resistance alloy resistors with a resistance value of 1-2 mΩ and a thickness of 0.6±0.1 mm.

[0048] The present invention also provides an ultra-thin low-resistance alloy resistor prepared by the above preparation method.

[0049] Due to the above technical solutions, compared with the prior art, the beneficial effects of the present invention are as follows: The preparation method of the ultra-thin low-resistance alloy resistor of the present invention can effectively reduce the side etching amount of the product, ensure the stability of the etched resistance value of the product under the condition of relatively low overall thickness of the product. Under the same etching conditions, by adopting the double-sided etching method, the side etching amount of the product is halved, and the etching time is reduced by half, improving the production efficiency. Brief description of the drawings

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0051] Figure 1 It is a process flow diagram for preparing an ultra-thin low-resistance alloy resistor in Embodiment 1 of the present invention; Figure 2 It is a schematic diagram of the side etching effect of double-sided etching in the embodiment of the present invention; Figure 3 It is a schematic diagram of the side etching effect of single-sided etching in the prior art. Detailed description of the specific embodiments

[0052] To enable those skilled in the art to better understand the technical solution of the present invention, the following will clearly and completely describe the technical solution in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0053] For alloys of the same thickness and under the same etching conditions, the side etching amount of single-sided etching is at least twice that of double-sided etching. The existing preparation methods of alloy material resistors mainly use stamping or etching. The stamping method has a high cost and relatively low efficiency; the side etching amount of single-sided etching is large and difficult to control. Using the double-sided etching method to prepare ultra-thin low-resistance alloy resistors can effectively reduce the side etching amount of the product on the premise of ensuring a small product thickness, which is beneficial to the stability of the product, reduces production costs, and improves production efficiency.

[0054] The ultra-thin low-resistance alloy resistor of the present invention is prepared through the following steps: 1. Stick dry films on both sides of the alloy sheet, and then perform exposure and development to form a first circuit pattern on the dry film.

[0055] Before sticking the dry film, the alloy sheet needs to be pretreated to remove the oxidation substances and oil stains on the surface of the alloy sheet.

[0056] Sticking the dry film means using a laminator to press the upper and lower surfaces of the alloy sheet with the dry film; the pressing time is 55 - 65s, the pressing pressure is 40 - 50KG, and the pressing temperature is 130 - 150°C.

[0057] Further, during exposure, for the dry films on both sides of the alloy sheet, the same set of optical alignment marks is used for alignment to make the positions of the second circuit patterns on both sides of the alloy sheet completely corresponding, and the shapes of the second circuit patterns on both sides of the alloy sheet are exactly the same, so that after subsequent etching, the second circuit patterns on both sides are completely penetrated to form a set circuit pattern.

[0058] Preferably, the alloy sheet is formed by cutting an alloy coil; the thickness of the alloy coil is 0.3 - 0.4mm.

[0059] 2. Etch to form second circuit patterns corresponding to the first circuit pattern on the dry film on both sides of the alloy sheet.

[0060] During etching, both sides of the alloy sheet are etched simultaneously, and the etching conditions are kept consistent. The etching conditions are an acidic etching solution, the etching speed is 1 - 3m / min; the etching temperature is 45 ± 5°C.

[0061] During etching, as the etching progresses, the etching depth of the second circuit patterns on both sides of the alloy sheet gradually increases and finally penetrates through the thickness direction of the alloy sheet, thereby obtaining a set circuit pattern on the alloy sheet and completing the etching.

[0062] 3. Remove the film to remove the dry film on the alloy sheet, and at this time, an alloy sheet with a set circuit pattern is obtained.

[0063] 4. Bond the alloy sheet to the substrate to obtain a sheet material.

[0064] An epoxy resin film is provided between the alloy sheet and the substrate, and then pre-pressing is first performed, followed by vacuum pressing using a vacuum press.

[0065] The pressing time for pre-pressing is 100 - 150 s, the pressing pressure is 20 - 30 KG, and the pressing temperature is 140 - 160 °C. The pressing time for vacuum pressing is 280 - 320 s, the pressing pressure is 50 - 70 KG, and the pressing temperature is 140 - 160 °C.

[0066] 5. Post-process the sheet material to obtain an ultra-thin low-resistance alloy resistor with a resistance value of 1 - 2 mΩ and a thickness of 0.6 ± 0.1 mm.

[0067] The post-processing includes primary printing, copper plating, resistance trimming, secondary printing, grain separation, and barrel plating performed in sequence. When the sheet material is used to form multiple ultra-thin low-resistance alloy resistors, the post-processing includes the step of grain separation. If the sheet material is only used to form one ultra-thin low-resistance alloy resistor, grain separation is not required in the post-processing.

[0068] Among them, the primary printing step is used to print protective ink to protect the resistor body for subsequent copper plating at the electrode; resistance trimming is used to correct the resistance value of the alloy resistor to a set resistance value; the secondary printing step is used to print protective ink again and cover the resistance trimming cut.

[0069] Example 1 As Figure 1 and Figure 2 shown, the preparation method of the ultra-thin low-resistance alloy resistor in this example includes the following steps: S1. Cutting Cut the alloy coil into alloy sheets with a size of 200 mm * 200 mm and a thickness of 0.3 mm, and each alloy sheet is subsequently used to form multiple ultra-thin low-resistance alloy resistors.

[0070] S2. Pretreatment Pretreat the surface of the alloy sheet to remove the oxides and oil stains on the surface of the alloy sheet, which is beneficial to the full adhesion of the subsequent dry film to the alloy sheet.

[0071] The pretreatment is specifically as follows: The alloy sheet is pretreated with a micro-etching solution to remove surface oil and oxides. The micro-etching speed is 2.5 m / min, and the micro-etching temperature is 45 ± 5°C.

[0072] The micro-etching solution is a mixed solution formed by sulfuric acid and hydrogen peroxide. The concentration of sulfuric acid in the mixed solution is 5%; the concentration of hydrogen peroxide is 5%.

[0073] S3. Double-sided laminating Using a laminating machine, the upper and lower surfaces of the alloy sheet are fully laminated with the dry film.

[0074] The lamination parameters include a lamination time of 60 s, a lamination pressure of 45 KG, and a lamination temperature of 140°C.

[0075] S4. Exposure and development The upper and lower surfaces of the alloy sheet with the dry film attached are exposed, and then developed to obtain a first circuit pattern with a predetermined shape on the dry film on the upper and lower surfaces of the alloy sheet.

[0076] Since it is necessary to ensure that the circuit patterns on the upper and lower surfaces of the alloy sheet are completely corresponding, in this embodiment, the same set of alignment mark points is used on the upper and lower surfaces during graphic exposure to ensure the complete correspondence of the first circuit patterns on the two-sided dry films, so that the positions and shapes of the second circuit patterns on the alloy sheet are completely corresponding, and then the final set circuit pattern is obtained.

[0077] S5. Double-sided etching The developed alloy sheet undergoes an etching operation. During etching, a double-sided synchronous etching method is adopted, so that the upper and lower surfaces of the alloy sheet simultaneously obtain the second circuit patterns corresponding to the first circuit patterns on the dry film. The positions and shapes of the second circuit patterns on the two surfaces of the alloy sheet are completely the same, so as to form a through-set circuit pattern in the thickness of the alloy sheet after etching. The etching conditions on the upper and lower surfaces are the same to reduce the side etching amount and improve the etching efficiency.

[0078] Acidic etching solution is used for etching. The etching speed is 2.5 m / min, and the etching temperature is 45 ± 5°C. The acidic etching solution is a mixed solution formed by copper chloride and hydrochloric acid. The concentration of copper chloride in the mixed solution is 90%, and the concentration of hydrochloric acid is 8%.

[0079] S6. Stripping The etched alloy sheet is subjected to a stripping treatment to remove the dry film on the surface of the alloy sheet. At this time, an alloy sheet with a set circuit pattern is obtained.

[0080] The stripping speed is 1.5 m / min, and the stripping temperature is 45 ± 5°C.

[0081] S7. Bonding the substrate First, set an epoxy resin film between one side of the etched alloy sheet and the substrate; then perform pre - lamination, and then use a vacuum press for vacuum lamination to obtain a sheet.

[0082] The lamination time for pre - lamination is 120 s, the lamination pressure is 25 KG, and the lamination temperature is 145 °C. The lamination time for vacuum lamination is 300 s, the lamination pressure is 65 KG, and the lamination temperature is 145 °C.

[0083] S8. Post - treatment The post - treatment includes primary printing, copper plating, resistance trimming, secondary printing, grain separation, and barrel plating in sequence. Specifically as follows: S81. Primary printing The laminated sheet is printed with a protective ink for the first time to protect the alloy resistor body for subsequent copper plating at the electrode.

[0084] S82. Copper plating After primary printing, copper plating is carried out to make the electrodes of the ultra - thin low - resistance alloy resistor product.

[0085] S83. Resistance trimming After copper plating, resistance trimming is carried out to make the resistance value of the product within the set range.

[0086] S84. Secondary printing After resistance trimming, the protective ink is printed for the second time to cover the cut edge of the resistance trimming.

[0087] S85. Grain separation When the sheet is used to form multiple ultra - thin low - resistance alloy resistors, after resistance trimming, the semi - finished sheet is cut into grains to form multiple individual ultra - thin low - resistance alloy resistors.

[0088] S86. Nickel - tin plating Barrel plating of nickel - tin is carried out at the corresponding electrodes of the grain - separated ultra - thin low - resistance alloy resistor product to obtain an ultra - thin low - resistance alloy resistor with a resistance value of 1 mΩ and a thickness of 0.6 ± 0.1 mm.

[0089] Example 2 The difference between the preparation method of the ultra - thin low - resistance alloy resistor in this example and that in Example 1 is only the difference in parameters. The steps and methods are basically the same. The different parameters are given below: The micro - etching solution used in the pretreatment of step S2 is a mixed solution formed by sulfuric acid and hydrogen peroxide. The concentration of sulfuric acid in the mixed solution is 4%; the concentration of hydrogen peroxide is 4%. Micro - etching speed: 1.5 m / min, micro - etching temperature: 45 ± 5 °C.

[0090] The lamination parameters for double - sided film pasting in step S3 include a lamination time of 55 s, a lamination pressure of 50 KG, and a lamination temperature of 150 °C.

[0091] In step S5 of double-sided etching, the etching speed is 1 m / min; the etching temperature is 45 ± 5 °C. The acidic etching solution is a mixed solution formed by copper chloride and hydrochloric acid. The concentration of copper chloride in the mixed solution is 95%, and the concentration of hydrochloric acid is 5%.

[0092] In step S6 of stripping the film, the stripping speed is 1 m / min; the stripping temperature is 45 ± 5 °C.

[0093] In step S7 of laminating the substrate, the lamination time for pre-lamination is 100 s, the lamination pressure is 30 KG, and the lamination temperature is 160 °C. The lamination time for vacuum lamination is 280 s, the lamination pressure is 70 KG, and the lamination temperature is 160 °C.

[0094] The finally obtained ultra-thin low-resistance alloy resistor has a resistance value of 1.5 mΩ and a thickness of 0.6 ± 0.1 mm.

[0095] Example 3 The difference between the preparation method of the ultra-thin low-resistance alloy resistor in this example and that in Example 1 lies only in the different parameters. The steps and methods are basically the same. The different parameters are given below: In step S2 of pretreatment, the micro-etching solution used is a mixed solution formed by sulfuric acid and hydrogen peroxide. The concentration of sulfuric acid in the mixed solution is 6%; the concentration of hydrogen peroxide is 6%. The micro-etching speed is 3 m / min, and the micro-etching temperature is 45 ± 5 °C.

[0096] The lamination parameters for double-sided film lamination in step S3 include a lamination time of 65 s, a lamination pressure of 40 KG, and a lamination temperature of 130 °C.

[0097] In step S5 of double-sided etching, the etching speed is 3 m / min; the etching temperature is 45 ± 5 °C. The acidic etching solution is a mixed solution formed by copper chloride and hydrochloric acid. The concentration of copper chloride in the mixed solution is 90%, and the concentration of hydrochloric acid is 10%.

[0098] In step S6 of stripping the film, the stripping speed is 2 m / min; the stripping temperature is 45 ± 5 °C.

[0099] In step S7 of laminating the substrate, the lamination time for pre-lamination is 150 s, the lamination pressure is 20 KG, and the lamination temperature is 140 °C. The lamination time for vacuum lamination is 320 s, the lamination pressure is 50 KG, and the lamination temperature is 140 °C.

[0100] The finally obtained ultra-thin low-resistance alloy resistor has a resistance value of 2 mΩ and a thickness of 0.6 ± 0.1 mm. Comparative Example 1

[0101] Using the method in the background technology, that is, after laminating the alloy and the substrate, single-sided film lamination and exposure development are carried out, and then the resistor body semi-finished product is obtained by single-sided etching. Subsequently, a single resistor product is obtained through solder resist, electroplating, cutting, and barrel plating methods.

[0102] That is, the difference between this comparative example and Example 1 is that in this comparative example, the substrate lamination in step S7 of Example 1 is carried out before step S3, and step S3 is single-sided film lamination. Correspondingly, step S5 is single-sided etching. The remaining steps, parameters are basically the same as those in Example 1. Testing and Results

[0103] (1) Test the undercut amount (undercut depth) of the etched alloy sheets in the examples and comparative examples: Take samples to make polished sections and measure the dimensions under an optical microscope. The results are as Figure 2 and 3 shown.

[0104] Among them, Figure 2 is a schematic diagram of double-sided etching in Example 1, and its undercut depth is 18.929 μm; Figure 3 is a schematic diagram of single-sided etching in Comparative Example 1, and its undercut depth is 55.554 μm.

[0105] (2) Measure the target resistance product of 1 mΩ.

[0106] Resistance measurement method: Weld the resistance product to the test board, measure the resistance by the four-wire measurement method, and test multiple products to count their resistances.

[0107] After testing and statistics, the resistance value of the resistance product obtained by single-sided etching in Comparative Example 1 is 1 mΩ * (1 - 10%), and the resistance value of the resistance product obtained by double-sided etching in Example 1 is 1 mΩ * (1 - 3%). The resistor products prepared by the method of the example have higher precision.

[0108] It can be seen that the undercut depth and undercut amount of double-sided etching in the embodiments of the present invention are much lower than those of single-sided etching. The double-sided etching of the present invention can effectively reduce the undercut amount of the product, ensure the stability of the etched resistance value of the product, shorten the etching time at the same time, and improve the production efficiency.

[0109] Before etching the product of the present invention, dry films are pasted on both sides of the alloy sheet, circuit exposure and development are carried out, and then the circuits are etched on both sides of the sheet at the same time. After etching is completed, it is laminated with the substrate, and after subsequent processes such as primary solder resist, electrode copper plating, resistance trimming, secondary solder resist, cutting, and barrel plating, single products are obtained. It can reduce the undercut amount of alloy sheet etching, which is beneficial to improving the stability of the product resistance value; at the same time, under the same etching conditions, by using the double-sided etching method, the undercut amount of the product is halved, and the time consumed in the etching section is reduced by half, improving the production efficiency.

[0110] The above embodiments are only used to illustrate the technical concept and features of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly. However, the protection scope of the present invention cannot be limited thereby. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

[0111] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

Claims

1. A preparation method of an ultra-thin low-resistance alloy resistor, characterized in that, It includes the following steps: Dry films are attached to both sides of the alloy sheet, and then exposure and development are carried out to form a first circuit pattern on the dry film; Etching is performed so that second circuit patterns corresponding to the first circuit pattern on the dry film are formed on both sides of the alloy sheet; The dry film on the alloy sheet is removed; The alloy sheet is attached to the substrate to obtain a sheet; The sheet is post-treated to obtain the ultra-thin low-resistance alloy resistor.

2. The preparation method according to claim 1, wherein, The second circuit patterns on both sides of the alloy sheet are exactly the same, and after the etching is completed, the second circuit patterns penetrate through the thickness of the alloy sheet to form corresponding set circuit patterns.

3. The preparation method according to claim 1, wherein During the etching, both sides of the alloy sheet are etched simultaneously, and the etching conditions are kept consistent.

4. The preparation method according to claim 1 or 3, characterized in that, The etching conditions are to use an acidic etching solution, with an etching speed of 1 - 3 m / min and an etching temperature of 45 ± 5 °C.

5. The preparation method according to claim 1, characterized in that, The preparation of the sheet is to set a glue film between the alloy sheet and the substrate, and then pre-pressing is carried out first, followed by vacuum pressing.

6. The preparation method according to claim 5, characterized in that, The pre-pressing time is 100 - 150 s, the pressing pressure is 20 - 30 KG, and the pressing temperature is 140 - 160 °C; and / or, The vacuum pressing time is 280 - 320 s, the pressing pressure is 50 - 70 KG, and the pressing temperature is 140 - 160 °C.

7. The preparation method according to claim 1, wherein Attaching the dry film is to use a laminator to press the dry film onto the upper and lower surfaces of the alloy sheet; the pressing time is 55 - 65 s, the pressing pressure is 40 - 50 KG, and the pressing temperature is 130 - 150 °C.

8. The preparation method according to claim 1, wherein, The post-treatment includes one-time printing, copper plating, secondary printing, granulation, and barrel plating carried out in sequence.

9. The preparation method according to claim 8, characterized in that, The post-treatment includes a resistance trimming step after copper plating, which is used to trim the resistance value of the alloy resistor to a set resistance value.

10. The preparation method according to claim 9, characterized in that, The secondary printing is used to print the protective material again and cover the resistance trimming edge.

11. The preparation method according to claim 1, wherein The steps include a pre-treatment step before attaching the dry film, which is used to remove the oxidation substances and oil stains on the surface of the alloy sheet.

12. The preparation method according to claim 1, characterized in that, During the exposure, for the dry films on both sides of the alloy sheet, the same set of optical alignment marks are used for alignment.

13. The preparation method according to claim 1, wherein The alloy sheet is formed by cutting an alloy coil; the thickness of the alloy sheet is 0.3 - 0.4 mm.

14. The preparation method according to claim 1, characterized in that, The resistance value of the ultra-thin low-resistance alloy resistor is 1 - 2 mΩ, and the thickness is 0.6 ± 0.1 mm.

15. An ultra-thin low-resistance alloy resistor prepared by the preparation method according to any one of claims 1 - 14.

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