Manufacturing method suitable for alloy foil resistor

Abstract

The invention discloses a manufacturing method suitable for an alloy foil resistor. The manufacturing method comprises the following steps: 1, curing a substrate and pasting a film; 2, pattern transfer; 3, developing, etching and removing the film; 4, printing a protective layer before rack plating; 5, exposing and developing the protective layer before rack plating; 6, rack plating; 7, plating bridge cutting; 8, precisely adjusting the resistance; 9, printing a protective layer; 10, marking and printing; 11, the protection layer mark is cured; 12, laser scribing; 13, performing primary segmentation; 14, performing vacuum sputtering; 15, carrying out secondary segmentation; sixthly, barrel plating of copper, nickel and tin is conducted. According to the invention, by introducing an innovative alloy foil resistor manufacturing process, the resistance precision of the alloy foil resistor is greatly improved, the purpose of automatic resistance adjustment of the high-precision alloy foil resistor is achieved, and the stability and consistency of the product are improved.

Description

Technical Field

[0001] The invention relates to the technical field of alloy foil resistors, in particular to a manufacturing method suitable for alloy foil resistors. Background Art

[0002] In the half century since the invention of alloy foil resistors, alloy foil resistor technology has always been superior to all current resistor process technologies in applications such as high precision, high stability, and high reliability. For a long time, there has been little public information on the production process of alloy foil resistors at home and abroad, and people often lack a systematic understanding of the process technology of alloy foil resistors, which has limited the technical development of products to a certain extent. Alloy foil resistors have many advantages over traditional thick film resistors. The temperature coefficient of resistance is a parameter affected by the microstructure of the resistor material. In the absence of defects and impurities, there is a theoretical maximum value. For ideal pure metals, such as pure copper and silver, due to their strict lattice arrangement and efficient electron migration, the resistivity is much lower than that of alloy materials, but the temperature coefficient is much higher than that of alloy materials. Resistors made of pure metals are large in size and consume a lot of materials. Within the range of 15°-30°, their resistance value can change by 3%-6%, so they are not suitable as materials for precision resistors. Another is that stress will be accumulated or defective products will appear during product processing, which will have a great impact on the stability of the product.

[0003] Therefore, it is necessary to provide a manufacturing method suitable for alloy foil resistors to solve the above technical problems. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for manufacturing alloy foil resistors, characterized in that it comprises the following steps:

[0006] 1. Substrate curing and film lamination: First, glue the alloy coil, cut the alloy coil into shape, and then press and cure it together with the ceramic sheet;

[0007] 2. Pattern transfer: First, a layer of exposure dry film is applied to the surface of the solidified alloy, and then the pattern is transferred to the alloy surface through exposure;

[0008] 3. Development, etching and film stripping: Determine the dry film pattern through development, etch out the alloy pattern through wet etching, and remove the surface dry film to form an alloy substrate with a pattern;

[0009] 4. Printing the protective layer before rack plating: Print the solder mask before rack plating on the alloy surface by screen printing; 5. Exposure and development of the protective layer before rack plating: Use an exposure machine to expose the printed photosensitive wet film with an exposure accuracy of ±10um to accurately control the size of the wet film layer; Put the exposed alloy substrate into the developing line and develop the protective layer by spraying;

[0010] 6. Rack plating: Use an automatic rack plating line to rack plate the alloy substrate covered with a protective wet film. By adjusting the current parameters and aeration rate, the copper thickness accuracy on the electrode surface is controlled within ±20um;

[0011] 7. Cutting of plating bridge: Cut the plating bridge of the alloy substrate after rack plating by laser;

[0012] 8. Precision resistance adjustment: After the alloy substrate is stripped after rack plating, the product is precisely adjusted through the laser resistance trimming system;

[0013] 9. Protective layer printing: Print the protective layer on the alloy surface by screen printing;

[0014] 10. Marking printing: Printing a marking layer on the alloy surface by screen printing;

[0015] 11. Protective layer and marking curing: the alloy substrate coated with the protective layer and the marking layer is placed in a special oven for baking and hardening, so that the protective layer ink and the marking layer ink are cured and firmly attached to the alloy surface and the ceramic substrate;

[0016] 12. Laser scribing: Use laser to pre-score the entire ceramic surface before splitting. 13. One-time splitting: Use a strip folding machine to fold the alloy sheet into strips, and arrange each strip evenly into a split jig;

[0017] 14. Vacuum sputtering: Place the stripped fixture in a vacuum sputtering coating machine, and establish a vacuum environment through a vacuum pumping system. The sputtered material flies in the vacuum environment and is finally deposited on the side of the ceramic substrate to form the required alloy layer.

[0018] 15. Secondary segmentation: Use a pelletizer to form the product pellets after the strips are sputtered;

[0019] 16. Roll plating of copper, nickel and tin: Use an automatic roll plating line to electroplate copper, nickel and tin on the surface of the product electrode to form a single product.

[0020] A preferred embodiment of the manufacturing method for alloy foil resistors is that in step 1, the alloy roll in the substrate curing film is cut into a shape equal to the size of the ceramic sheet and cured after being bonded to the ceramic substrate, the curing temperature is about 150° C., and the curing time is 50 to 70 minutes.

[0021] A preferred solution of the manufacturing method suitable for alloy foil resistors is that UV-LED ultraviolet light is used for exposure in the step 2 of pattern transfer, and the exposure energy is controlled to be 100-250 mj / cm.

[0022] A preferred solution of the manufacturing method suitable for alloy foil resistors is as follows: in the step 3, developing and etching the film, an alkaline solution with a pH value between 18 and 12 is used for development, and the development time is 30s±10s; an acid etching solution is used to etch the alloy, and the engraving size accuracy is controlled to be ±15um; an alkaline solution with a pH value between 10 and 14 is used to strip the alloy substrate, and the stripping time is 10±5 minutes, and the film is baked after stripping; in the step 3, an alkaline solution with a concentration of 0.2% to 1.4% is used for development, and the developer parameters are a time of 10 to 30s and a cleaning time of 20 to 45s, and the ceramic substrate is etched on both sides.

[0023] A preferred embodiment of the manufacturing method for alloy foil resistors is that the protective layer in step nine is formed by printing the alloy plate on the front side of the photosensitive ink, and printing the screen with the prepared ink, and the surface is uniform and free of bubbles and sags.

[0024] In a preferred embodiment of the manufacturing method for alloy foil resistors, in step thirteen, laser engraving is performed on the ceramic substrate to facilitate segmentation, and the depth of the engraved lines is not less than 0.08 mm.

[0025] A preferred solution of the manufacturing method suitable for alloy foil resistors is that the rack plating adopts electroplating. Before electroplating, the workpiece needs to be subjected to a series of pretreatments to ensure that the workpiece surface is clean, free of oil and oxide, thereby improving the adhesion and quality of the coating.

[0026] In a preferred embodiment of the manufacturing method for alloy foil resistors, the protective layer mark is cured by thermal curing.

[0027] In a preferred embodiment of the method for manufacturing alloy foil resistors, the laser scribing is performed by laser scanning, where a laser beam is rapidly scanned on the surface of the material by a high-speed scanning head to form continuous or discontinuous lines.

[0028] In a preferred embodiment of the manufacturing method for alloy foil resistors, the protective layer material before printing and plating includes ultraviolet curing ink, thermosetting ink or liquid photoresist.

[0029] The beneficial effects of the present invention are as follows: the present invention adds the fifteenth and sixteenth processes, the fifteenth process improves the success rate of product particle forming, the sixteenth process is more convenient for electroplating the electrode surface by roller plating, and the present invention introduces an innovative alloy foil resistor manufacturing process, so that the resistance accuracy of the alloy foil resistor is greatly improved, and the purpose of automatic resistance adjustment of high-precision alloy foil resistors is achieved, and the stability and consistency of the product are improved; the present invention also has the following characteristics: (1) the line edges are smooth and neat, and the size meets the requirements of the base plate; (2) the resistance value is close to the target resistance value and the dispersion is small; (3) there is no side corrosion, islands or broken wires, and the yield rate is high; (4) the layout pattern is clear and clean, and there is no residue of the corrosive medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0031] in:

[0032] Figure 1 A schematic diagram of the process steps of a method for manufacturing an alloy foil resistor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0034] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0035] Secondly, the present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0036] Furthermore, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0037] Example 1

[0038] Reference Figure 1 The first embodiment of the present invention is a method for manufacturing an alloy foil resistor, characterized in that it comprises the following steps:

[0039] 1. Substrate curing and film lamination: First, glue the alloy coil, cut the alloy coil into shape, and then press and cure it together with the ceramic sheet;

[0040] 2. Pattern transfer: First, a layer of exposure dry film is applied to the surface of the solidified alloy, and then the pattern is transferred to the alloy surface through exposure;

[0041] 3. Development, etching and film stripping: Determine the dry film pattern through development, etch out the alloy pattern through wet etching, and remove the surface dry film to form an alloy substrate with a pattern;

[0042] 4. Printing the protective layer before rack plating: Use screen printing to print the solder mask layer before rack plating on the alloy surface; 5. Exposure and development of the protective layer before rack plating: Use an exposure machine to expose the printed photosensitive wet film, with an exposure accuracy of ±10um, which can accurately control the size of the wet film layer; Put the exposed alloy substrate into the development line, and develop the protective layer by spraying; 6. Rack plating: Use an automatic rack plating line to rack plate the alloy substrate covered with a protective wet film. By adjusting the current parameters and aeration rate, the copper thickness accuracy of the electrode surface can be controlled within ±20um;

[0043] 7. Cutting of plating bridge: Cut the plating bridge of the alloy substrate after rack plating by laser;

[0044] 8. Precision resistance adjustment: After the alloy substrate is stripped after rack plating, the product is precisely adjusted through the laser resistance trimming system;

[0045] 9. Protective layer printing: Print the protective layer on the alloy surface by screen printing;

[0046] 10. Marking printing: Printing a marking layer on the alloy surface by screen printing;

[0047] 11. Protective layer and marking curing: the alloy substrate coated with the protective layer and the marking layer is placed in a special oven for baking and hardening, so that the protective layer ink and the marking layer ink are cured and firmly attached to the alloy surface and the ceramic substrate;

[0048] 12. Laser scribing: Use laser to pre-score the entire ceramic surface before splitting. 13. One-time splitting: Use a strip folding machine to fold the alloy sheet into strips, and arrange each strip evenly into a split jig;

[0049] 14. Vacuum sputtering: Place the stripped fixture in a vacuum sputtering coating machine, and establish a vacuum environment through a vacuum pumping system. The sputtered material flies in the vacuum environment and is finally deposited on the side of the ceramic substrate to form the required alloy layer.

[0050] 15. Secondary segmentation: Use a pelletizer to form the product pellets after the strips are sputtered;

[0051] 16. Roll plating of copper, nickel and tin: Use an automatic roll plating line to electroplate copper, nickel and tin on the surface of the product electrode to form a single product.

[0052] Specifically, substrate curing film is an important step in the process of manufacturing alloy foil resistors. It is mainly used to protect the surface of alloy foil and substrate. Substrate curing film usually includes the following steps:

[0053] 1. Substrate Preparation

[0054] Substrate selection: Choose the appropriate substrate material. Commonly used ones include ceramic substrates (such as alumina Al2O3, aluminum nitride AlN), glass substrates, FR-4 (epoxy resin glass fiber), etc.

[0055] Substrate cleaning: Use chemical cleaning agents and ultrasonic cleaning machines to thoroughly remove oil, dust and oxides on the surface of the substrate to ensure that the substrate surface is clean and flat.

[0056] 2. Film material selection

[0057] Protective film: Choose the appropriate protective film material, commonly used are polyimide (PI), polyester (PET), polytetrafluoroethylene (PTFE), etc. These materials have good high temperature resistance, chemical corrosion resistance and insulation properties.

[0058] Adhesive: Choose the right adhesive to ensure that the protective film can be firmly attached to the substrate. Commonly used adhesives include epoxy resin, acrylate, etc.

[0059] 3. Film pasting process

[0060] Film laminating equipment: Use a dedicated film laminating machine or manual film laminating tool to ensure that the protective film is evenly and flatly attached to the substrate.

[0061] Film application steps:

[0062] Pretreatment: Apply a thin layer of adhesive on the substrate surface, ensuring that the adhesive is evenly distributed.

[0063] Film sticking: Carefully stick the protective film on the substrate, starting from one end and gradually sticking it together to avoid bubbles and wrinkles.

[0064] Exhaust: Use a roller or scraper to gently roll to exhaust the air under the protective film to ensure a tight fit.

[0065] 4. Curing process

[0066] Pre-curing: Place the substrate with the film attached into a pre-curing oven and pre-cure it at a lower temperature (such as 80-100°C) for a few minutes to initially fix the protective film.

[0067] High temperature curing: Place the pre-cured substrate into a high temperature curing oven and perform high temperature curing at a higher temperature (such as 150-200°C) to ensure that the adhesive is fully cured and the protective film is firmly attached to the substrate.

[0068] Cooling: After curing is completed, slowly cool the substrate to room temperature to avoid the protective film from falling off or the substrate from deforming due to excessive temperature difference.

[0069] 5. Inspection and repair

[0070] Appearance inspection: Use a microscope or naked eyes to check the substrate after film application to ensure that the protective film is flat, free of bubbles and wrinkles.

[0071] Edge trimming: If necessary, use a blade or scissors to trim the edges of the protective film to ensure a neat and beautiful appearance.

[0072] In the step 1, the alloy roll in the substrate curing film is cut into the same size as the ceramic sheet for curing. First, the ceramic sheets are bonded and pre-processed after cutting. After the dry film is bonded, the dry film is exposed. After the dry film is developed, the dry film is etched. In the step 3, the development is carried out in an alkaline solution with a concentration of 0.2% to 1.4%. The parameters of the developer are 10 to 30 seconds and a cleaning time of 20 to 45 seconds to etch the ceramic substrate on both sides. Development, etching and film stripping are key steps in the process of manufacturing alloy foil resistors, which are used to accurately control the shape and size of the alloy foil to achieve the desired resistance value. These steps generally include the following specific operations:

[0073] 1. Development

[0074] Development refers to the process of transferring the pre-designed pattern onto the alloy foil through photolithography. The steps are as follows:

[0075] Coating photoresist;

[0076] (1) Photoresist selection: Select appropriate photosensitive material (photoresist), such as positive photoresist or negative photoresist.

[0077] (2) Coating: Use spin coating, spray coating or dip coating to evenly coat the photoresist on the surface of the alloy foil.

[0078] exposure;

[0079] (1) Mask alignment: Align the designed mask (photomask) with the alloy foil coated with photoresist.

[0080] (2) Ultraviolet light irradiation: Ultraviolet light (UV) is used to irradiate the photoresist to cause chemical changes. Positive photoresist dissolves in the exposed area, and negative photoresist hardens in the exposed area.

[0081] Development includes;

[0082] (1) Developer: Use developer (such as NaOH solution) to dissolve the unexposed photoresist to expose part of the alloy foil.

[0083] (2) Rinse: Rinse with deionized water to remove residual developer and dissolved photoresist.

[0084] 2. Etching

[0085] Etching refers to removing the exposed alloy foil part by chemical or physical methods to form the desired pattern. The steps are as follows:

[0086] There are two types of etching solutions: (1) Chemical etching: Choose a suitable etching solution, such as iron chloride (FeCl3), sulfuric acid (H2SO4), etc.

[0087] (2) Physical etching: using physical methods such as plasma etching or laser etching.

[0088] The etching process is as follows:

[0089] (1) Soaking: Soak the developed alloy foil in an etching solution, which will dissolve the exposed alloy foil portion.

[0090] (2) Monitoring: Ensure that the etching depth and shape meet the design requirements through timed or online monitoring.

[0091] (3) Rinse: Rinse with deionized water to remove residual etching solution.

[0092] 3. Stripping: Stripping refers to removing the remaining photoresist to expose the complete alloy foil pattern. The steps are as follows:

[0093] (1) Select the stripping solution:

[0094] (2) Chemical stripping: Choose a suitable stripping solution, such as sulfuric acid (H2SO4), hydrogen peroxide (H2O2), etc.

[0095] (3) Physical stripping: using physical methods such as plasma cleaning or ultrasonic cleaning.

[0096] The film removal process is as follows:

[0097] (1) Soaking: Soak the etched alloy foil in the stripping solution, which will dissolve the remaining photoresist.

[0098] (2) Monitoring: Ensure that the photoresist is completely removed to expose a clear alloy foil pattern.

[0099] (3) Rinse: Rinse with deionized water to remove residual stripping solution.

[0100] 4. Wash and dry

[0101] Cleaning: Rinse the alloy foil thoroughly with deionized water to ensure there is no residual chemical residue.

[0102] Drying: Use hot air drying or vacuum drying to thoroughly dry the alloy foil.

[0103] 5. Inspection

[0104] (1) Appearance inspection: Use a microscope or optical inspection equipment to check whether the pattern of the alloy foil is complete and clear.

[0105] (2) Dimension measurement: Use optical measuring instruments to measure the width and length of the alloy foil to ensure that it meets the design requirements.

[0106] Resistance value test: Use a high-precision resistance meter to measure whether the resistance value meets the specification requirements. Double-sided etching adopts the dry etching method. Dry etching requires a dedicated ion beam etcher. The dry etching time is long and the efficiency is very slow, but the qualified rate of the finished product is high; the dry etching process is slow, so it is easy to control the etching rate and obtain fine resistance lines; dry etching can be applied to the etching of various resistance patterns. Dry etching is a more advanced etching process, but when making alloy foil resistors, the requirements for ion beam etcher are relatively high. The dry method involves the coordination between the ion source, power supply system, and control system. In order to achieve high-precision processing technology, this article has selected a variety of dry etching processes. The thickness of the printed film layer is related to the wire diameter, mesh number and thickness of the screen, as shown in formula (1-1)

[0107]

[0108] Among them, t is the printed wet film thickness, N is the mesh number of the screen, d is the wire diameter, and h is the screen thickness.

[0109] As the screen thickness increases, the dry film thickness of the printed resistor also increases, the conductive cross-sectional area of ​​the resistor increases, the flow rate increases, and the resistance value of the resistor decreases. When the screen thickness is (60+1) mm, it is very suitable for the production of ultra-high resistance chip thick film fixed resistors.

[0110] In the step 2, UV-LED ultraviolet light is used for exposure in the pattern transfer, and the exposure energy is controlled to be 100-250 mj / cm.

[0111] In the step 3, the development and etching stripping is performed in an alkaline solution with a pH value between 18 and 12, and the development time is 30s±10s; the alloy is etched using an acidic etching solution, and the engraving size accuracy is controlled to be ±15um; the alloy substrate is stripped using an alkaline solution with a pH value between 10 and 14, and the stripping time is 10±5 minutes, and the stripping is followed by baking; in the step 3, the ceramic substrate is double-sidedly etched using an alkaline solution with a concentration of 0.2% to 1.4%, and the developer parameters are a time of 10 to 30s and a cleaning time of 20 to 45s.

[0112] The protective layer material before the printing rack plating includes ultraviolet curing ink, thermosetting ink or liquid photoresist. There are various materials and methods for the protective layer before printing rack plating. The rack plating adopts the electroplating method. Before electroplating, the workpiece needs to undergo a series of pre-treatments to ensure that the workpiece surface is clean, oil-free and oxide-free, thereby improving the adhesion and quality of the coating. The selection of suitable protective layer materials and methods depends on the material, shape, size and electroplating requirements of the workpiece. By reasonably selecting and optimizing the protective layer materials and methods, the accuracy and quality of the electroplating process can be ensured, unnecessary plating areas can be avoided, and the performance and reliability of the product can be improved. The curing method adopted for curing the protective layer mark is thermal curing. The laser scribing adopts a laser scanning method for scribing, and the laser beam is quickly scanned on the surface of the material by a high-speed scanning head to form continuous or intermittent lines.

[0113] For example: UV curing ink, UV curing ink is a protective layer material that cures under ultraviolet light, suitable for application scenarios that require rapid curing. It includes the following steps:

[0114] 1. Printing: Use screen printing or inkjet printing to print UV curing ink on the surface of the workpiece.

[0115] 2. Curing: Use ultraviolet light (UV) to cure the ink in a short time.

[0116] 3. Electroplating: The electroplating process is carried out to plate metal only in the areas not covered by ink.

[0117] 4. Stripping: After electroplating is completed, use solvents or mechanical methods to remove the remaining ink.

[0118] Printing pressure plays a decisive role in the degree of slurry passing through. If the printing pressure is too small, the slurry will not easily pass through the mesh and will be blocked in the mesh, causing sticking or blocking. On the contrary, if the printing pressure is too large, the deformation of the scraper will be large, which will seriously shorten the service life of the screen and scraper. There are currently two control methods: one is open-loop control, which sets the printing pressure and cannot control the actual printing pressure in real time. The other is closed-loop control, which can monitor the printing pressure in real time. As the screen pressure increases, the thickness of the printed dry film of the resistor becomes thinner, and the resistance value increases at the same time. The reason for the analysis is that the greater the pressure of the scraper on the screen, the less the amount of resistor slurry remains on the printed ceramic substrate, and the film thickness of the resistor becomes thinner. However, if the pressure is too small, the slurry cannot be pushed away evenly, and the uniformity of the resistor body pattern is poor: when the pressure is too large, the screen will be severely deformed, and the printed pattern of the resistor body will also be deformed, accompanied by uneven film thickness. Therefore, too much or too little printing pressure will make the resistance value of the resistor body more discrete. When the resistor body pattern is deformed, the cross-section of the resistor body will also change, thus affecting the resistance value. The film thickness of the resistor body becomes thinner, the cross-section of the resistor body decreases, the through-current decreases, and the resistance value increases. The protective layer in the step six is ​​made by printing the alloy plate on the front of the photosensitive ink, and printing the screen with the prepared ink, and the surface is uniform without bubbles and sags. The surface roughness of the ceramic substrate after roughening is less than 6 microns. In order to facilitate segmentation, laser engraving is used on the ceramic substrate, and the depth of the engraving is not less than 0.08 mm scratch. Print the back electrode, the back electrode as part of the resistor can improve the conductivity of the resistor and reduce the resistance value, thereby meeting the requirements of the electronic equipment for the resistor performance. The protective layer mark is cured, and the mark curing refers to the process of fixing the mark and making it indelible through a specific process after printing or engraving the mark on the surface of the resistor. The solder mask is usually composed of an insulating slurry, which is used to prevent short circuits and corrosion of devices and lines on the circuit board. Mark curing can ensure that the resistor's identification is clear and durable, which is convenient for identification and tracing in subsequent production, testing and maintenance processes.

[0119] The steps of copper-nickel-tin barrel plating and the functions of each step:

[0120] 1. Pre-treatment

[0121] The purpose of pretreatment is to clean the workpiece surface, remove oil, oxides and other impurities, ensure that the workpiece surface is clean and pollution-free, and improve the adhesion of the coating. The steps are as follows:

[0122] 1. Degreasing:

[0123] (1) Tools: Use alkaline degreasing agent.

[0124] (2) Function: Remove oil and grease from the surface of the workpiece.

[0125] (3) Method: Soak the workpiece in a degreasing agent, or use spraying, ultrasonic, etc. to degrease.

[0126] 2. Pickling:

[0127] (1) Tools: Use acidic solutions such as sulfuric acid, hydrochloric acid, etc.

[0128] (2) Function: Remove oxides and rust from the surface of workpieces.

[0129] (3) Method: Soak the workpiece in pickling solution, or use spraying, ultrasonic and other methods for pickling.

[0130] 3. Activation:

[0131] (1) Tools: Use an activator such as dilute sulfuric acid.

[0132] (2) Function: Activate the surface of the workpiece and enhance its conductivity and chemical activity.

[0133] (3) Method: Soak the workpiece in activation liquid, or use spraying, ultrasonic and other methods for activation.

[0134] 4. Washing:

[0135] (1) Tools: Use deionized water or tap water.

[0136] (2) Function: Remove residual chemicals on the surface of the workpiece.

[0137] (3) Method: Clean the workpiece thoroughly with deionized water or tap water.

[0138] 2. Copper barrel plating

[0139] Roll copper plating is the first step of the electroplating process. The copper layer can provide good conductivity and bottom layer protection. The steps are as follows:

[0140] 1. Loading:

[0141] (1) Tools: Use roller.

[0142] (2) Function: Place the pre-treated workpiece into the drum.

[0143] (3) Method: Ensure that the workpieces are evenly distributed in the drum to avoid mutual obstruction.

[0144] 2. Electroplating:

[0145] (1) Tools: Use copper plating solution and DC power supply.

[0146] (2) Function: Deposit a layer of copper on the surface of the workpiece.

[0147] (3) Method: Place the drum in the copper plating solution, connect the power supply, and perform electroplating. Adjust the current density, voltage, and time to ensure that the copper layer is uniform and dense.

[0148] 3. Washing:

[0149] (1) Tools: Use deionized water or tap water.

[0150] (2) Function: Remove residual copper plating solution on the surface of the workpiece.

[0151] (3) Method: Clean the workpiece thoroughly with deionized water or tap water.

[0152] 3. Barrel Nickel Plating

[0153] Roll nickel plating is the second step of the electroplating process. The nickel layer can provide good corrosion resistance and wear resistance. The steps are as follows:

[0154] 1. Loading:

[0155] (1) Tools: Use roller.

[0156] (2) Function: Place the workpiece after copper plating into the drum.

[0157] (3) Method: Ensure that the workpieces are evenly distributed in the drum to avoid mutual obstruction.

[0158] 2. Electroplating:

[0159] (1) Tools: Use nickel plating solution and DC power supply.

[0160] (2) Function: Deposit a layer of nickel on the surface of the workpiece.

[0161] (3) Method: Place the drum in the nickel plating solution, connect the power supply, and perform electroplating. Adjust the current density, voltage, and time to ensure that the nickel layer is uniform and dense.

[0162] 3. Washing:

[0163] (1) Tools: Use deionized water or tap water.

[0164] (2) Function: Remove residual nickel plating solution on the surface of the workpiece.

[0165] (3) Method: Clean the workpiece thoroughly with deionized water or tap water.

[0166] 4. Roll tin plating

[0167] Roll tinning is the third step of the electroplating process. The tin layer provides good solderability and corrosion resistance. The steps are as follows:

[0168] 1. Loading:

[0169] (1) Tools: Use roller.

[0170] (2) Function: Place the workpiece after roller nickel plating into the roller.

[0171] (3) Method: Ensure that the workpieces are evenly distributed in the drum to avoid mutual obstruction.

[0172] 2. Electroplating:

[0173] (1) Tools: Use tin plating solution and DC power supply.

[0174] (2) Function: Deposit a layer of tin on the surface of the workpiece.

[0175] (3) Method: Place the drum in the tin plating solution, connect the power supply, and perform electroplating. Adjust the current density, voltage, and time to ensure that the tin layer is uniform and dense.

[0176] 3. Washing:

[0177] (1) Tools: Use deionized water or tap water.

[0178] (2) Function: Remove residual tin plating solution on the surface of the workpiece.

[0179] (3) Method: Clean the workpiece thoroughly with deionized water or tap water.

[0180] 5. Post-processing

[0181] The purpose of post-treatment is to remove residual chemicals on the surface of the workpiece and improve the performance and appearance quality of the coating. The steps are as follows:

[0182] 1. Passivation:

[0183] (1) Tools: Use passivation liquid such as chromate, phosphate, etc.

[0184] (2) Function: Improve the corrosion resistance of the coating.

[0185] (3) Method: Immerse the workpiece in the passivation solution, or use spraying, ultrasonic and other methods for passivation.

[0186] 2. Drying:

[0187] (1) Tools: Use hot air drying or infrared drying equipment.

[0188] (2) Function: Remove moisture from the workpiece surface to ensure that the workpiece is dry.

[0189] (3) Method: Place the workpiece in a drying device for drying.

[0190] 3. Inspection:

[0191] (1) Tools: Use microscopes, optical detection equipment, etc.

[0192] (2) Function: Check the thickness, uniformity and appearance quality of the coating.

[0193] (3) Method: Perform visual inspection, thickness measurement and performance testing on the workpiece to ensure that it meets quality requirements.

[0194] The ceramic substrate to be divided is cut by plating bridge. After cutting, the plating bridge is flat and the electrode has no obvious protrusions, and then put into the laser marking machine. The ceramic substrate divided into particles is inspected by the appearance machine and the detection ability is confirmed.

[0195] In summary, the present invention greatly improves the resistance accuracy of alloy foil resistors by introducing an innovative alloy foil resistor manufacturing process, achieves the purpose of automatic resistance adjustment of high-precision alloy foil resistors, and improves the stability and consistency of the product.

[0196] It is important to note that the construction and arrangement of the present application shown in a number of different exemplary embodiments are illustrative only. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application.

[0197] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0198] It will be appreciated that in the development of any actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will be a routine task of design, fabrication, and production for those of ordinary skill having the benefit of this disclosure without undue experimentation.

[0199] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for manufacturing an alloy foil resistor, characterized in that: The following steps are involved:

1. Substrate curing and film lamination: First, glue the alloy coil, cut the alloy coil into shape, and then press and cure it together with the ceramic sheet; 2. Pattern transfer: First, a layer of exposure dry film is applied to the surface of the solidified alloy, and then the pattern is transferred to the alloy surface through exposure; 3. Development, etching and film stripping: Determine the dry film pattern through development, etch out the alloy pattern through wet etching, and remove the surface dry film to form an alloy substrate with a pattern; 4. Printing the protective layer before rack plating: Use screen printing to print the solder mask before rack plating on the alloy surface; 5. Exposure and development of the protective layer before rack plating: Use an exposure machine to expose the printed photosensitive wet film with an exposure accuracy of ±10um to accurately control the size of the wet film layer; put the exposed alloy substrate into the development line and develop the protective layer by spraying; 6. Rack plating: Use an automatic rack plating line to rack plate the alloy substrate covered with a protective wet film. By adjusting the current parameters and aeration rate, the copper thickness accuracy on the electrode surface is controlled within ±20um; 7. Cutting of plating bridge: Cut the plating bridge of the alloy substrate after rack plating by laser; 8. Precision resistance adjustment: After the alloy substrate is stripped after rack plating, the product is precisely adjusted through the laser resistance trimming system; 9. Protective layer printing: Print the protective layer on the alloy surface by screen printing; 10. Marking printing: Printing a marking layer on the alloy surface by screen printing; 11. Protective layer and marking curing: the alloy substrate coated with the protective layer and the marking layer is placed in a special oven for baking and hardening, so that the protective layer ink and the marking layer ink are cured and firmly attached to the alloy surface and the ceramic substrate; 12. Laser scribing: Use laser to pre-score the entire ceramic surface before splitting; 13. One-time splitting: Use a strip folding machine to fold the alloy sheet into strips, and arrange each strip evenly into a one-division fixture; 14. Vacuum sputtering: Place the stripped fixture in a vacuum sputtering coating machine, and establish a vacuum environment through a vacuum pumping system. The sputtered material flies in the vacuum environment and is finally deposited on the side of the ceramic substrate to form the required alloy layer.

15. Secondary segmentation: Use a pelletizer to form the product pellets after the strips are sputtered; 16. Roll plating of copper, nickel and tin: Use an automatic roll plating line to electroplate copper, nickel and tin on the surface of the product electrode to form a single product.

2. The method for manufacturing an alloy foil resistor according to claim 1, characterized in that: In the step 1, the alloy roll in the substrate curing film is cut into a shape and size equal to the ceramic sheet and bonded to the ceramic substrate before curing. The curing temperature is about 150° C. and the curing time is 50 to 70 minutes.

3. The method for manufacturing an alloy foil resistor according to claim 1, characterized in that: In the step 2, UV-LED ultraviolet light is used for exposure in the pattern transfer, and the exposure energy is controlled to be 100-250 mj / cm.

4. The method for manufacturing an alloy foil resistor according to claim 1, characterized in that: In the step 3, the development and etching stripping is performed in an alkaline solution with a pH value between 18 and 12, and the development time is 30s±10s; the alloy is etched using an acidic etching solution, and the engraving size accuracy is controlled to be ±15um; the alloy substrate is stripped using an alkaline solution with a pH value between 10 and 14, and the stripping time is 10±5 minutes, and the stripping is followed by baking; in the step 3, the ceramic substrate is double-sidedly etched using an alkaline solution with a concentration of 0.2% to 1.4%, and the developer parameters are a time of 10 to 30s and a cleaning time of 20 to 45s.

5. The method for manufacturing an alloy foil resistor according to claim 1, characterized in that: The protective layer in step nine is made by printing the alloy plate on the front side of the photosensitive ink, and printing the screen with the prepared ink, and the surface is uniform without bubbles and sag.

6. The method for manufacturing an alloy foil resistor according to claim 1, characterized in that In step thirteen, in order to facilitate segmentation, laser engraving is used on the ceramic substrate, and the depth of the engraved lines is not less than 0.08 mm.

7. The method for manufacturing an alloy foil resistor according to claim 1, characterized in that : The rack plating adopts the electroplating method. Before electroplating, the workpiece needs to undergo a series of pre-treatments to ensure that the workpiece surface is clean, oil-free and oxide-free, thereby improving the adhesion and quality of the coating.

8. The method for manufacturing an alloy foil resistor according to claim 1, characterized in that : The curing method adopted for curing the protective layer mark is thermal curing.

9. The method for manufacturing an alloy foil resistor according to claim 1, characterized in that The laser marking method is to use laser scanning to mark the surface of the material by quickly scanning the laser beam through a high-speed scanning head to form continuous or intermittent lines.

10. The method for manufacturing alloy foil resistor according to claim 1, characterized in that: The protective layer material before printing and plating includes ultraviolet curing ink, thermosetting ink or liquid photoresist.

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