High quality surge resistant and sulfur resistant wafer resistor and method of making same

Abstract

This invention relates to the technical field of resistors, specifically to a high-quality surge-resistant and sulfide-resistant wafer resistor and its preparation method. The resistor comprises a white substrate, a resistive layer, a protective layer, and an electrode assembly. The white substrate is an alumina ceramic substrate with a thickness of 0.2-0.6 mm. The resistive layer is formed by sintering ruthenium-based thick-film resistive paste and is disposed between the protective layer and the white substrate. The electrode assembly includes a first front electrode, a second front electrode, a back electrode, and a side electrode. The first front electrode, the second front electrode, and the back electrode are all elongated plates. The white substrate is located between the first front electrode and the back electrode, and the contact area between the first front electrode and the upper surface of the white substrate is not less than 1 / 4 of the upper surface area of ​​the white substrate. One side of the second front electrode is in close contact with the first front electrode. This invention reduces the contact channel between sulfide gas and the electrodes, significantly improving the service life of the resistor in harsh environments.

Description

Technical Field

[0001] This invention relates to the technical field of resistors, specifically to a high-quality surge-resistant and sulfide-resistant wafer resistor and its preparation method. Background Technology

[0002] According to market research reports, the global market size for surge-resistant and anti-sulfurization wafer resistors is projected to reach approximately US$497 million in 2029, with a compound annual growth rate of approximately 13.2%. This is primarily driven by the rapid development of the Internet of Things (IoT), 5G communication infrastructure construction, electric vehicles (EVs), and autonomous driving technologies. These fields place stringent demands on the high reliability, stability, and durability of resistors. However, existing resistors still suffer from a short lifespan under high-power and high-frequency operating environments.

[0003] Based on this, the present invention designs a high-quality surge-resistant and sulfide-resistant wafer resistor and its preparation method to solve the above problems. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution: a high-quality surge-resistant and sulfide-resistant wafer resistor, comprising a white substrate, a resistive layer, a protective layer, and an electrode assembly. The white substrate is an alumina ceramic substrate with a thickness of 0.2-0.6 mm. The resistive layer is formed by sintering ruthenium-based thick-film resistive paste with a thickness of 5-20 μm, and is disposed between the protective layer and the white substrate. The electrode assembly includes a first front electrode, a second front electrode, a back electrode, and a side electrode. The first front electrode, the second front electrode, and the back electrode are all in the shape of elongated plates with an aspect ratio of 3-5:1. The white substrate is located between the first front electrode and the back electrode, and the first front electrode is attached to the white substrate. The bonding area of ​​the surface is not less than 1 / 4 of the surface area of ​​the white substrate. One side of the second front electrode is in close contact with the first front electrode, and the bonding length is 0.5-1.2mm. The side electrode is integrally formed and connected to the free end of the second front electrode and the free end of the back electrode. The side of the second front electrode away from the first front electrode is in close contact with the protective layer. The outer surface of the side electrode is fully covered by a first isolation layer. Two electrode groups are symmetrically arranged on the white substrate, and the distance between the two electrode groups is 0.68~5mm. The resistive layer is horizontally laid between the two electrode groups, and the two ends of the resistive layer are fixedly connected to the first front electrode of the two electrode groups respectively.

[0005] Preferably, the side electrode includes a side electrode plate, an upper electrode plate, and a lower electrode plate. The side electrode plate, upper electrode plate, and lower electrode plate are integrally bent to form a "U"-shaped structure. The thickness of the side electrode plate is 8-15 μm. The thickness of the upper electrode plate and the lower electrode plate are the same as that of the side electrode plate. The length of the upper electrode plate is adapted to the length of the free end of the second front electrode, and the length of the lower electrode plate is adapted to the length of the free end of the back electrode. The free end of the second front electrode, the edge portion of the first front electrode, the side end of the white substrate, and the free end of the back electrode are all housed in the cavity of the "U"-shaped structure. The upper electrode plate is welded and fixed to the upper surface of the free end of the second front electrode, and the lower electrode plate is welded and fixed to the lower surface of the free end of the back electrode. The first insulating layer completely covers the outer surface of the side electrode, and the thickness of the first insulating layer is 9-15 μm.

[0006] Preferably, the outer surface of the first isolation layer is completely covered by a second isolation layer, which is an electroplated nickel layer with a purity of not less than 99.5%, a thickness of 4~7.5um, and an adhesion force between the nickel layer and the first isolation layer of not less than 15N / mm².

[0007] Preferably, the outer surface of the second isolation layer is completely covered by a third isolation layer, which is an electroplated tin layer with a purity of not less than 99.8%, a thickness of 4.5~10.5, and no oxidation spots on the surface of the tin layer with uniform gloss.

[0008] Preferably, the side electrode is made of a nickel-chromium alloy, wherein the nickel content is 80-85 wt%, the chromium content is 15-20 wt%, and the resistivity of the alloy is 1.0-1.5 × 10⁻⁶. -6 Ω·m, and has undergone high-temperature annealing treatment at 400-450℃.

[0009] Preferably, the protective layer includes a first protective layer and a second protective layer. The first protective layer is tightly attached to the upper surface of the resistive layer. The first protective layer is formed by sintering a low-melting-point glass paste. The sintering temperature of the glass paste is 600℃, and the softening temperature begins to soften at 500~750℃. The thickness of the first protective layer after sintering is 7~15μm. The second protective layer completely covers the outer surface of the first protective layer and the side edges of the resistive layer. The second protective layer is made of high-temperature resistant epoxy resin. The glass transition temperature of the epoxy resin is not lower than 220℃±5℃, and the thickness is 15-30μm.

[0010] Preferably, the first protective layer has an upwardly convex arched structure, and the distance between the highest point of the arch and the upper surface of the resistive layer is 0.1-0.3 mm. The outline of the second protective layer that adheres to the first protective layer is also arched, and the arched outline of the second protective layer is concentrically set with the arched outline of the first protective layer. The gap between the two is uniform and the gap width is 2-5 μm.

[0011] The manufacturing process for high-quality surge-resistant and sulfide-resistant wafer resistors includes the following steps: Step 1: Provide a white alumina ceramic substrate with an alumina content of not less than 96%, grind and polish the surface of the substrate to make the surface roughness Ra≤0.2μm, and then clean it with ultrasonic cleaning and dry it for later use. Step 2: Silver palladium electrode paste is printed on the lower surface of a white substrate using screen printing technology with a printing accuracy of ±0.02mm. After printing, it is dried at 180℃±5℃ for 30-40min, and then placed in a sintering furnace and sintered at 850℃ for 45-60min to form two separate back electrodes with a spacing of 0.68-5mm. Step 3: Silver palladium electrode paste is printed on the upper surface of the white substrate at the position corresponding to the back electrode using screen printing technology. The printing accuracy is ±0.02mm. After printing, it is dried at 180℃ for 15min and then placed in a sintering furnace and sintered in air at 850℃ for 45~60min to form two separate left and right first front electrodes. The first front electrodes and the back electrode are symmetrically arranged vertically. Step 4: Use screen printing technology to print ruthenium-based thick film resistive paste on the upper surface of the white substrate, so that the paste covers the area between the two first front electrodes and overlaps with the first front electrodes at both ends, with an overlap width of 0.3-0.5mm. After printing, dry at 180℃ for 15min, and then place it in a sintering furnace and sinter in air at 850℃ for 45-60min to form a resistive layer connecting the left and right first front electrodes. Step 5: Use screen printing to print low melting point glass paste on the upper surface of the resistive layer, covering the entire resistive layer. After printing, dry at 180°C for 15 minutes, and then place it in a sintering furnace and sinter in air at 600°C for 45-60 minutes to form an arched first protective layer. Step 6: High-temperature resistant epoxy resin is printed on the surface of the first protective layer using screen printing technology. The coating covers the entire outer surface of the first protective layer and the side edges of the resistive layer. After printing, it is dried at 180°C for 15 minutes, and then sintered in a sintering furnace at 220°C for 45~60 minutes to form an arched second protective layer. Step 7: Using screen printing, nickel-silver alloy electrode paste is printed on the free ends of the two first front electrodes to form the second front electrode. The printing accuracy is ±0.02mm. After printing, drying and sintering treatment are performed. Step 8: Place the substrate in a magnetron sputtering apparatus, use nickel-chromium alloy as the target material, and sputter the side electrodes on both sides in an argon atmosphere. The sputtering power is 1800~2200W to form side electrodes that connect the front electrode and the corresponding back electrode. Step 9: Place the substrate with the side electrode in an electroplating bath, use copper sulfate as the electroplating solution, control the current density to be 2-5 A / dm², and the electroplating time to be 98-102 min. Electroplat a layer of metallic copper on the entire outer surface of the substrate to form a first isolation layer that completely covers the back electrode, side electrode, first front electrode, second front electrode and outermost protective layer. The thickness of the first isolation layer is 9-15 μm. Step 10: Place the copper-plated substrate in another electroplating tank, use nickel sulfate as the electroplating solution, control the current density to be 1-3 A / dm², and the electroplating time to be 98-102 min. Electroplat a layer of metallic nickel on the outer surface of the first isolation layer to form a second isolation layer. The thickness of the second isolation layer is 4-7.5 μm. Step 11: Place the nickel-plated substrate in the third electroplating tank, use stannous sulfate as the electroplating solution, control the current density to be 1-2 A / dm², and the electroplating time to be 98-102 min. Electroplat a layer of metallic tin on the outer surface of the second isolation layer to form the third isolation layer. The thickness of the third isolation layer is 4.5-10 μm. After electroplating, wash and dry the substrate to obtain the finished resistor.

[0012] Preferably, in step 8, after the printing material of the second front electrode is dried at 180°C for 15 minutes, it is sintered simultaneously at 220°C in a nitrogen atmosphere for 60 minutes. After sintering, the thickness of the second front electrode is 10-15 μm, and the bonding force with the first front electrode is not less than 12 N / mm².

[0013] In summary, this application has the following beneficial technical effects: 1. Multi-layer isolation layer synergistic protection, blocking the path of sulfide corrosion: The application clearly defines the full-encapsulation design of the first, second, and third isolation layers, forming a dense metal protection system. The copper layer has a purity ≥99.9% and a porosity ≤0.5%, which can effectively block the penetration of sulfur-containing gases; the bonding force between the nickel layer and the copper layer is ≥15N / mm², further enhancing the isolation effect; the tin layer has both anti-oxidation and soldering aid functions. The three-layer structure works together to prevent the electrodes from reacting with sulfides to generate low-resistance / high-resistance impurities such as silver sulfide and nickel sulfide, fundamentally solving the problem of traditional resistors being prone to failure in sulfur-containing environments; 2. Fully enclosed electrode structure protection: The side electrode adopts a U-shaped integrated structure, which completely houses the free end of the second front electrode, the edge of the first front electrode, the side end of the white substrate, and the free end of the back electrode within the cavity. Combined with the welding and fixing of the upper electrode plate to the second front electrode and the lower electrode plate to the back electrode, the exposed area of ​​the electrodes is reduced. At the same time, the first isolation layer fully wraps the side electrode, further reducing the contact channel between the sulfide gas and the electrode, and significantly improving the service life of the resistor in harsh environments. 3. Wide electrode and multi-layer electrode design to reduce current density: The first front electrode, second front electrode, and back electrode are all elongated plates, and the bonding area between the first front electrode and the upper surface of the white substrate is ≥1 / 4 of the substrate's upper surface area. The bonding length between the second front electrode and the first front electrode is 0.5-1.2 mm. Combined with a 15-25 μm thick electrode layer formed by three-stage printing of silver-palladium electrodes, the conductive cross-sectional area of ​​the electrodes is significantly increased. This design can reduce the current density of the electrodes and resistive layer when surge current passes through, avoiding local overheating and burnout or electrode melting, and improving surge resistance. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the resistor structure in this embodiment; Figure 2 This is a schematic diagram of the side electrode structure in this embodiment; Figure 3 This is a flowchart of the resistor manufacturing process in this embodiment.

[0016] The attached diagram lists the components represented by each number as follows: 1. White substrate; 2. Resistive layer; 3. First protective layer; 4. Second protective layer; 5. First front electrode; 6. Second front electrode; 7. Back electrode; 8. Side electrode; 9. Side electrode plate; 10. Upper electrode plate; 11. Lower electrode plate; 12. First isolation layer; 13. Second isolation layer; 14. Third isolation layer. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0019] A high-quality surge-resistant and sulfide-resistant wafer resistor includes a white substrate 1, a resistive layer 2, a protective layer, and an electrode assembly. The connection relationships and parameters of each structure are as follows: White substrate 1: It is an alumina ceramic substrate with a thickness of 0.2-0.6mm, which serves as the basic support structure for the entire resistor.

[0020] Resistor layer 2: Corresponding to resistor layer 2R in the attached figure, it is sintered from ruthenium oxide thick film resistor paste with a thickness of 5-20μm. It is set between the protective layer and the white substrate 1 and is the core structure for realizing the resistor function.

[0021] Electrode assembly: includes a first front electrode 5, a second front electrode 6, a back electrode 7, and a side electrode 8, wherein the first front electrode 5, the second front electrode 6, and the back electrode 7 are all in the shape of long plates with an aspect ratio of 3-5:1; a white substrate 1 is located between the first front electrode 5 and the back electrode 7, and the bonding area between the first front electrode 5 and the upper surface of the white substrate 1 is not less than 1 / 4 of the upper surface area of ​​the white substrate 1; one side of the second front electrode 6 is in close contact with the first front electrode 5, and the bonding length is 0.5-1.2mm; the side electrode 8 is integrally formed and connected to the free end of the second front electrode 6 and the free end of the back electrode 7, and the side of the second front electrode 6 away from the first front electrode 5 is in close contact with the protective layer; the outer surface of the side electrode 8 is sequentially covered with a first isolation layer 12, a second isolation layer 13, and a third isolation layer 14.

[0022] Electrode group distribution: Two electrodes are symmetrically arranged on the white substrate 1, with a spacing of 0.68~5mm between the two electrode groups. The resistive layer 2 is horizontally laid between the two electrode groups, and the two ends of the resistive layer 2 are fixedly connected to the first front electrode 5 of the two electrode groups respectively.

[0023] Preferably, the side electrode 8 includes a side electrode plate 9, an upper electrode plate 10, and a lower electrode plate 11. The side electrode plate 9, the upper electrode plate 10, and the lower electrode plate 11 are integrally bent to form a "U"-shaped structure. The thickness of the side electrode plate 9 is 8-15 μm. The thickness of the upper electrode plate 10 and the lower electrode plate 11 is the same as that of the side electrode plate 9. The length of the upper electrode plate 10 is adapted to the length of the free end of the second front electrode 6, and the length of the lower electrode plate 11 is adapted to the length of the free end of the back electrode 7. The free end of the second front electrode 6, the edge portion of the first front electrode 5, the side end of the white substrate 1, and the free end of the back electrode 7 are all housed in the cavity of the "U"-shaped structure. The upper electrode plate 10 is welded and fixed to the upper surface of the free end of the second front electrode 6, and the lower electrode plate 11 is welded and fixed to the lower surface of the free end of the back electrode 7. The first isolation layer 12 completely covers the outer surface of the side electrode 8, and the thickness of the first isolation layer 12 is 9-15 μm.

[0024] Preferably, the first isolation layer 12 is an electroplated copper layer with a purity of not less than 99.9% and a porosity of not more than 0.5%, which can effectively block the permeation of sulfur-containing gases. Preferably, the outer surface of the first isolation layer 12 is completely covered by a second isolation layer 13, which is an electroplated nickel layer with a purity of not less than 99.5% and a thickness of 4~7.5um, and the bonding force between the nickel layer and the first isolation layer 12 is not less than 15N / mm², further enhancing the isolation effect.

[0025] Preferably, the outer surface of the second isolation layer 13 is completely covered by a third isolation layer 14. The third isolation layer 14 is an electroplated tin layer with a purity of not less than 99.8%, a thickness of 4.5~10.5 mm, and no oxidation spots on its surface. It has uniform gloss and functions as both an anti-oxidant and a soldering aid. Preferably, the side electrode 8 is made of a nickel-chromium alloy, wherein the nickel content is 80-85 wt%, the chromium content is 15-20 wt%, and the resistivity of the alloy is 1.0-1.5 × 10⁻⁶. -6 It has an Ω·m content and undergoes high-temperature annealing treatment at 400-450℃ to ensure structural stability and electrical conductivity.

[0026] Preferably, the protective layer includes a first protective layer 3 and a second protective layer 4: the first protective layer 3 is closely attached to the upper surface of the resistive layer 2, and is formed by sintering low melting point glass paste. The sintering temperature of the glass paste is 600℃, and the softening temperature begins to soften at 500~750℃. The thickness of the first protective layer 3 after sintering is 7~15μm, and it has an upwardly convex arched structure. The distance between the highest point of the arch and the upper surface of the resistive layer 2 is 0.1-0.3mm. The second protective layer 4 completely covers the outer surface of the first protective layer 3 and the side edge of the resistive layer 2. It is made of high-temperature resistant epoxy resin with a glass transition temperature of not less than 220℃±5℃ and a thickness of 15-30μm. Its outline is also arched and concentric with the arched outline of the first protective layer 3. The gap between the two is uniform and the gap width is 2-5μm, forming a double protective structure.

[0027] The manufacturing process of high-quality surge-resistant and sulfide-resistant wafer resistors includes the following steps: Step 1, providing a white alumina ceramic substrate with an alumina content of not less than 96%, grinding and polishing the surface of the substrate to make the surface roughness Ra≤0.2μm, and then cleaning it with ultrasonic waves and drying it for later use. Step 2: Silver palladium electrode paste is printed on the lower surface of the white substrate using screen printing technology with a printing accuracy of ±0.02mm. After printing, it is dried at 180℃±5℃ for 30-40min, and then placed in a sintering furnace and sintered at 850℃ for 45-60min to form two separate left and right back electrodes 7 with a spacing of 0.68-5mm. Step 3: Silver palladium electrode paste is printed on the upper surface of the white substrate at the position corresponding to the back electrode 7 using screen printing technology. The printing accuracy is ±0.02mm. After printing, it is dried at 180℃ for 15min and then placed in a sintering furnace and sintered in air at 850℃ for 45~60min to form two separate left and right first front electrodes 5. The first front electrodes 5 and the back electrode 7 are arranged symmetrically above and below. Step 4: Use screen printing technology to print ruthenium-based thick film resistive paste on the upper surface of the white substrate, so that the paste covers the area between the two first front electrodes 5, and the two ends overlap with the first front electrodes 5 with an overlap width of 0.3-0.5mm. After printing, dry at 180℃ for 15min, and then place it in a sintering furnace and sinter in air at 850℃ for 45~60min to form a resistive layer 2 connecting the left and right first front electrodes 5. Step 5: Low melting point glass paste is printed on the upper surface of the resistive layer 2 using screen printing technology. The printing area covers the entire resistive layer 2. After printing, it is dried at 180°C for 15 minutes and then placed in a sintering furnace and sintered in air at 600°C for 45~60 minutes to form an arched first protective layer 3. Step 6: High-temperature resistant epoxy resin is printed on the surface of the first protective layer 3 using screen printing technology. The coating covers the entire outer surface of the first protective layer 3 and the side edge of the resistive layer 2. After printing, it is dried at 180°C for 15 minutes, and then sintered in a sintering furnace at 220°C for 45~60 minutes to form an arched second protective layer 4. Step 7: Using screen printing, nickel-silver alloy electrode paste is printed on the free ends of the two first front electrodes 5 to form the second front electrode. The printing accuracy is ±0.02mm. After printing, drying and sintering are performed. Step 8: The substrate is placed in a magnetron sputtering device. Using nickel-chromium alloy as the target material, the side electrodes on both sides are sputtered in an argon atmosphere. The sputtering power is 1800~2200W to form the side electrode connecting the front electrode and the corresponding back electrode 7. Step 9: The substrate with the side electrode 8 is placed in an electroplating tank. Copper sulfate is used as the electroplating solution. The current density is controlled at 2-5A / dm² and the electroplating time is 98~102min. A layer of metallic copper is electroplated on the entire outer surface of the substrate to form a first isolation layer 12 that completely covers the back electrode 7, side electrode 8, first front electrode 5, second front electrode 6 and the outermost protective layer. The thickness of the first isolation layer 12 is 9~15um. Step 10: Place the copper-plated substrate in another electroplating tank, use nickel sulfate as the electroplating solution, control the current density to be 1-3 A / dm², and the electroplating time to be 98-102 min. Electroplat a layer of metallic nickel on the outer surface of the first isolation layer 12 to form the second isolation layer 13. The thickness of the second isolation layer 13 is 4-7.5 μm. Step 11: Place the nickel-plated substrate in the third electroplating tank, use stannous sulfate as the electroplating solution, control the current density to be 1-2 A / dm², and the electroplating time to be 98-102 min. Electroplat a layer of metallic tin on the outer surface of the second isolation layer 13 to form the third isolation layer 14. The thickness of the third isolation layer 14 is 4.5-10 μm. After electroplating, wash and dry the substrate to obtain the finished resistor.

[0028] Preferably, in step 8, after the printing material of the second front electrode 6 is dried at 180°C for 15 minutes, it is sintered simultaneously at 220°C in a nitrogen atmosphere for 60 minutes. After sintering, the thickness of the second front electrode 6 is 10-15 μm, and the bonding force with the first front electrode 5 is not less than 12 N / mm².

[0029] In summary, this application has the following beneficial technical effects: Multi-layered isolation layers work together to block the path of sulfide corrosion: The full-enclosure design of the first isolation layer 12 (high-purity electroplated copper layer), the second isolation layer 13 (high-purity electroplated nickel layer), and the third isolation layer 14 (high-purity electroplated tin layer) (copper plating layer, nickel plating layer, and tin plating layer are shown in the attached diagram from the inside out) forms a dense metal protection system; the copper layer has a purity ≥99.9% and a porosity ≤0.5%, effectively blocking the penetration of sulfur-containing gases; the bonding force between the nickel layer and the copper layer is ≥15N / mm², further enhancing the isolation effect; the tin layer also has anti-oxidation and soldering aid functions. The three-layer structure works together to prevent the electrodes (especially silver-palladium electrodes and nickel-chromium electrodes) from reacting with sulfides to generate low-resistivity / high-resistivity impurities such as silver sulfide and nickel sulfide, fundamentally solving the problem of traditional resistors easily failing in sulfur-containing environments (such as chemical, mining, and marine environments); 2. Fully Enclosed Electrode Structure Protection: The side electrode 8 adopts a U-shaped integrated structure (the U-shaped wrapping shape of the side electrode C3 in the attached figure), which completely accommodates the free end of the second front electrode 6, the edge of the first front electrode 5, the side end of the white substrate 1, and the free end of the back electrode 7 within the cavity. Combined with the welding and fixing of the upper electrode plate 10 to the second front electrode 6 and the lower electrode plate to the back electrode 7, the exposed area of ​​the electrodes is reduced. At the same time, the first isolation layer 12 fully encloses the side electrode 8, further eliminating the contact channel between sulfide gas and the electrodes, and significantly improving the service life of the resistor in harsh environments. 3. Wide electrode and multilayer electrode design to reduce current density: The first front electrode 5, the second front electrode 6, and the back electrode 7 are all elongated plates (length-to-diameter ratio 3-5:1), and the bonding area between the first front electrode 5 and the upper surface of the white substrate 1 is ≥1 / 4 of the upper surface area of ​​the substrate. The bonding length between the second front electrode 6 and the first front electrode 5 is 0.5-1.2mm. Combined with the 15-25μm thick electrode layer formed by the three-time printing of silver-palladium electrodes in step 5, the conductive cross-sectional area of ​​the electrodes is significantly increased (the width and thickness dimensions of each electrode are shown in the attached figure). This design can reduce the current density of the electrodes and resistive layer 2 when surge current passes through, avoid local overheating and burnout or electrode melting, and improve surge resistance.

[0030] In the description of this invention, it should be understood that the terms "coaxial," "bottom," "one end," "top," "middle," "other end," "upper," "side," "top," "inner," "front," "center," "both ends," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0031] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-quality surge-resistant and sulfidation-resistant wafer resistor, characterized in that: The system includes a white substrate (1), a resistive layer (2), a protective layer, and an electrode assembly. The white substrate (1) is an alumina ceramic substrate with a thickness of 0.2-0.6 mm. The resistive layer (2) is formed by sintering ruthenium-based thick film resistive paste with a thickness of 5-20 μm. The resistive layer (2) is disposed between the protective layer and the white substrate (1). The electrode assembly includes a first front electrode (5), a second front electrode (6), a back electrode (7), and a side electrode (8). The first front electrode (5), the second front electrode (6), and the back electrode (7) are all in the shape of long plates with an aspect ratio of 3-5:

1. The white substrate (1) is located between the first front electrode (5) and the back electrode (7), and the bonding area between the first front electrode (5) and the upper surface of the white substrate (1) is not less than that of the white substrate. (1) 1 / 4 of the upper surface area, the second front electrode (6) is in close contact with the first front electrode (5) on one side, with a contact length of 0.5-1.2mm. The side electrode (8) is integrally formed and connected to the free end of the second front electrode (6) and the free end of the back electrode (7). The side of the second front electrode (6) away from the first front electrode (5) is in close contact with the protective layer. The outer surface of the side electrode (8) is fully covered with the first isolation layer (12). There are two electrode groups symmetrically arranged on the white substrate (1). The distance between the two electrode groups is 0.68~5mm. The resistive layer (2) is horizontally laid between the two electrode groups, and the two ends of the resistive layer (2) are fixedly connected to the first front electrode (5) of the two electrode groups respectively.

2. The high-quality surge-resistant and sulfidation-resistant wafer resistor according to claim 1, characterized in that: The side electrode (8) includes a side electrode plate (9), an upper electrode plate (10), and a lower electrode plate (11). The side electrode plate (9), upper electrode plate (10), and lower electrode plate (11) are integrally bent into a "U" shape. The thickness of the side electrode plate (9) is 8-15 μm. The thickness of the upper electrode plate (10) and the lower electrode plate (11) is the same as that of the side electrode plate (9). The length of the upper electrode plate (10) is adapted to the length of the free end of the second front electrode (6), and the length of the lower electrode plate (11) is adapted to the length of the free end of the back electrode (7). The free end of the second front electrode (6), the edge portion of the first front electrode (5), the side end of the white substrate (1), and the free end of the back electrode (7) are all housed in the cavity of the "U"-shaped structure. The upper electrode plate (10) is welded and fixed to the upper surface of the free end of the second front electrode (6), and the lower electrode plate (11) is welded and fixed to the lower surface of the free end of the back electrode (7). The first isolation layer (12) completely covers the outer surface of the side electrode (8), and the thickness of the first isolation layer (12) is 9~15um.

3. The high-quality surge-resistant and sulfidation-resistant wafer resistor according to claim 2, characterized in that: The outer surface of the first isolation layer (12) is fully covered by the second isolation layer (13), which is an electroplated nickel layer with a purity of not less than 99.5% and a thickness of 4~7.5um. The bonding force between the nickel layer and the first isolation layer (12) is not less than 15N / mm².

4. The high-quality surge-resistant and sulfidation-resistant wafer resistor according to claim 3, characterized in that: The outer surface of the second isolation layer (13) is completely covered by the third isolation layer (14), which is an electroplated tin layer with a purity of not less than 99.8%, a thickness of 4.5~10.5, and no oxidation spots on the surface of the tin layer with uniform gloss.

5. The high-quality surge-resistant and sulfidation-resistant wafer resistor according to claim 4, characterized in that: The side electrode (8) is made of nickel-chromium alloy, wherein the nickel content is 80-85 wt%, the chromium content is 15-20 wt%, and the resistivity of the alloy is 1.0-1.5 × 10⁻ 6 Ω·m, and has undergone high-temperature annealing treatment at 400-450℃.

6. The high-quality surge-resistant and sulfidation-resistant wafer resistor according to claim 5, characterized in that: The protective layer includes a first protective layer (3) and a second protective layer (4). The first protective layer (3) is tightly attached to the upper surface of the resistive layer (2). The first protective layer (3) is formed by sintering low melting point glass paste. The sintering temperature of the glass paste is 600℃, and the softening temperature starts to soften at 500~750℃. The thickness of the first protective layer (3) after sintering is 7~15μm. The second protective layer (4) completely covers the outer surface of the first protective layer (3) and the side edge of the resistive layer (2). The second protective layer (4) is made of high temperature resistant epoxy resin. The glass transition temperature of the epoxy resin is not lower than 220℃±5℃, and the thickness is 15-30μm.

7. The high-quality surge-resistant and sulfidation-resistant wafer resistor according to claim 6, characterized in that: The first protective layer (3) has an upwardly convex arch structure. The distance between the highest point of the arch and the upper surface of the resistive layer (2) is 0.1-0.3 mm. The outline of the second protective layer (4) that is attached to the first protective layer (3) is also arched. The arched outline of the second protective layer (4) and the arched outline of the first protective layer (3) are concentrically set. The gap between the two is uniform and the gap width is 2-5 μm.

8. A manufacturing process for a high-quality surge-resistant and sulfide-resistant wafer resistor as described in claims 1-7, characterized in that: Includes the following steps: Step 1: Provide a white alumina ceramic substrate with an alumina content of not less than 96%, grind and polish the surface of the substrate to make the surface roughness Ra≤0.2μm, and then clean it with ultrasonic cleaning and dry it for later use. Step 2: Silver palladium electrode paste is printed on the lower surface of the white substrate using screen printing technology with a printing accuracy of ±0.02mm. After printing, it is dried at 180℃±5℃ for 30-40min and then placed in a sintering furnace. The sintering furnace is sintered at 850℃ for 45-60min to form two separate back electrodes (7) with a spacing of 0.68-5mm. Step 3: Silver palladium electrode paste is printed on the upper surface of the white substrate at the position corresponding to the back electrode (7) using screen printing technology. The printing accuracy is ±0.02mm. After printing, it is dried at 180℃ for 15min and then placed in a sintering furnace and sintered in air at 850℃ for 45~60min to form two separate left and right first front electrodes (5). The first front electrodes (5) and the back electrode (7) are symmetrically arranged vertically. Step 4: Use screen printing technology to print ruthenium-based thick film resistive paste on the upper surface of the white substrate, so that the paste covers the area between the two first front electrodes (5) and overlaps with the first front electrodes (5) at both ends, with an overlap width of 0.3-0.5mm. After printing, dry at 180℃ for 15min, and then place it in a sintering furnace and sinter in air at 850℃ for 45-60min to form a resistive layer (2) connecting the left and right first front electrodes (5). Step 5: Low melting point glass paste is printed on the upper surface of the resistive layer (2) using screen printing technology. The printing range covers the entire resistive layer (2). After printing, it is dried at 180°C for 15 minutes and then placed in a sintering furnace and sintered in air at 600°C for 45~60 minutes to form an arched first protective layer (3). Step 6: High-temperature resistant epoxy resin is printed on the surface of the first protective layer (3) using screen printing technology. The coating range covers the entire outer surface of the first protective layer (3) and the side edge of the resistive layer (2). After printing, it is dried at 180°C for 15 minutes, and then sintered in a sintering furnace at 220°C for 45~60 minutes to form an arched second protective layer (4). Step 7: Using screen printing, nickel-silver alloy electrode paste is printed on the free surface of the two first front electrodes (5) to form the second front electrode. The printing accuracy is ±0.02mm. After printing, drying and sintering are performed. Step 8: Place the substrate in a magnetron sputtering device, use nickel-chromium alloy as the target material, and sputter the side electrodes on both sides in an argon atmosphere. The sputtering power is 1800~2200W to form a side electrode (8) that connects the front electrode and the corresponding back electrode (7). Step 9: Place the substrate with the side electrode (8) in an electroplating tank, use copper sulfate as the electroplating solution, control the current density to be 2-5 A / dm², and the electroplating time to be 98-102 min. Electroplat a layer of metallic copper on the entire outer surface of the substrate to form a first isolation layer (12) that completely covers the back electrode (7), side electrode (8), first front electrode (5), second front electrode (6) and the outermost protective layer. The thickness of the first isolation layer (12) is 9-15 μm. Step 10: Place the copper-plated substrate in another electroplating tank, use nickel sulfate as the electroplating solution, control the current density to be 1-3 A / dm², and the electroplating time to be 98-102 min. Electroplat a layer of metallic nickel on the outer surface of the first isolation layer (12) to form the second isolation layer (13). The thickness of the second isolation layer (13) is 4-7.5 μm. Step 11: Place the nickel-plated substrate in the third electroplating tank, use stannous sulfate as the electroplating solution, control the current density to be 1-2 A / dm², and the electroplating time to be 98-102 min. Electroplat a layer of metallic tin on the outer surface of the second isolation layer (13) to form the third isolation layer (14). The thickness of the third isolation layer (14) is 4.5-10 μm. After electroplating, perform water washing and drying to obtain the finished resistor.

9. The manufacturing process of the high-quality surge-resistant and sulfide-resistant wafer resistor according to claim 8, characterized in that: In step 8, the printing material of the second front electrode (6) is dried at 180°C for 15 minutes and then sintered at 220°C in a nitrogen atmosphere for 60 minutes. After sintering, the thickness of the second front electrode (6) is 10-15 μm and the bonding force with the first front electrode (5) is not less than 12 N / mm².

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