A manufacturing process for reducing debris under PCB solder mask

Abstract

This invention discloses a process for reducing debris under PCB solder mask, including checking the condition of the water washing section of the pre-solder mask roughening line; installing an ultrasonic device on the water washing section of the pre-solder mask roughening line after inspection and confirmation to perform a 3-5 minute water washing on the PCB to achieve PCB cleaning; by adding an ultrasonic device to the water washing section of the pre-solder mask roughening line, the high-frequency vibration and cavitation effect can thoroughly remove impurities and microparticles from the PCB surface, reducing debris residue caused by incomplete cleaning; using a lint-free cloth made of polyester fiber and polypropylene fiber composite material to replace the traditional screen cleaning paper can eliminate debris generated by the shedding of screen cleaning paper fibers; replacing the metal dust removal roller in the screen printing exposure stage with a polycarbonate plastic bracket can avoid metal wear and debris and debris formed by electrostatic adsorption of human skin flakes, thereby effectively reducing the generation of debris under solder mask from multiple key aspects.

Description

Technical Field

[0001] This invention belongs to the field of printed circuit board manufacturing technology, specifically relating to a process method for reducing debris under the solder mask on a PCB. Background Technology

[0002] Solder masking is a key process in the manufacturing of printed circuit boards (PCBs). It protects the PCB from environmental factors such as atmosphere, moisture, contaminants, and electrical damage by coating the PCB surface with a solder mask layer. The process is mainly completed through a series of steps including coating, exposure, windowing, etching, and cleaning.

[0003] With the widespread use of electronic products, customers have increasingly higher requirements for PCB quality, especially in terms of product appearance. Under a 40x microscope, any impurities under the solder mask layer are unacceptable, posing a severe challenge to the PCB solder mask process.

[0004] Traditional solder mask processes are prone to contamination due to several factors. For example, incomplete cleaning of the pre-treatment ultra-coarsening lines can leave impurities and microparticles on the PCB surface. Improper selection of screen cleaning materials, such as traditional screen cleaning paper, can lead to fiber shedding and contamination. If the screen printing equipment is made of metal, such as metal dust rollers, wear and tear or static electricity can attract skin flakes and other debris. These issues result in contamination under the solder mask, affecting the PCB's surface quality, increasing scrap rates, and reducing production efficiency and economic benefits. Therefore, we need a manufacturing process to reduce contamination under the PCB solder mask. Summary of the Invention

[0005] The purpose of this invention is to provide a process method for reducing impurities under PCB solder resist. By adding an ultrasonic device to the water washing section of the pretreatment roughening line, the high-frequency vibration and cavitation effect can thoroughly remove impurities and microparticles from the PCB surface, reducing the amount of impurities left due to incomplete cleaning. Using a lint-free cloth made of polyester and polypropylene fiber composite material instead of traditional screen cleaning paper can eliminate impurities caused by screen cleaning paper fiber shedding. Replacing the metal dust removal roller in the screen printing exposure stage with a polycarbonate plastic support can avoid metal wear and debris and impurities formed by electrostatic adsorption of human skin flakes. Thus, the invention effectively reduces the generation of impurities under solder resist from multiple key aspects, addressing the problems mentioned in the background section of the prior art, such as incomplete cleaning of the pretreatment roughening line, improper selection of screen cleaning materials, and equipment material issues in the screen printing exposure stage. These problems can all lead to the generation of impurities under solder resist, thereby affecting the appearance quality of the PCB.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a manufacturing method for reducing debris under PCB solder mask, comprising the following steps: Inspect the condition of the water washing section of the pre-treatment roughening line for solder resist; After inspection and confirmation, the water washing section of the pre-treatment roughening line for solder resist is equipped with an ultrasonic device to wash the PCB for 3-5 minutes, thus achieving PCB cleaning. After cleaning the PCB surface, prepare a lint-free cloth made of polyester fiber and polypropylene fiber composite material. During the solder resist cleaning process, wipe the screen with the lint-free cloth in the order from the center to the edge, and replace the lint-free cloth in time after each use. After completing the solder resist cleaning operation, the screen printing exposure stage begins. The original metal dust removal roller is removed and replaced with a polycarbonate plastic bracket that is compatible with the equipment. After completing the above-mentioned steps of solder resist pretreatment, screen cleaning, and silkscreen exposure, the PCB is inspected.

[0007] Preferably, the ultrasonic device is set to a frequency of 20-40kHz and a power of 100-300W to wash the PCB with water for 3-5 minutes.

[0008] Preferably, when washing the PCB, the water temperature in the washing tank is controlled at 30-40℃.

[0009] Preferably, the cleanroom cloth needs to undergo a cleanroom cleaning process before use to remove any fibers and impurities that may remain on the cloth surface. The size of the cleanroom cloth is 20cm×20cm-30cm×30cm.

[0010] Preferably, before installation, the surface of the polycarbonate plastic bracket needs to be wiped with a lint-free cloth dampened with isopropyl alcohol, and the thickness of the polycarbonate plastic bracket is 2-5mm.

[0011] Preferably, when inspecting the PCB, the inspection scope covers the entire surface of the PCB, including corners and areas with dense wiring.

[0012] Preferably, the cleaning tank of the ultrasonic device is provided with multiple supports for placing PCBs, and the spacing between the supports is 5-10cm.

[0013] Preferably, the cleaning tank of the ultrasonic device is equipped with a detachable filter assembly, which is made of 500-800 mesh stainless steel filter screen.

[0014] Preferably, in the water washing section of the pretreatment roughening line for solder resist, the ultrasonic device is installed 1-1.5m away from the inlet of the water washing section, and 2-3 sets of staggered ultrasonic transducers are set along the PCB transmission direction.

[0015] Preferably, the surface of the polycarbonate plastic support is treated with an antistatic coating, the coating thickness is 5-10 μm, and the surface resistance is controlled at 10 Ω·cm. 6 -10 9 Ω.

[0016] Technical effects and advantages of the present invention: The manufacturing method for reducing debris under PCB solder mask proposed in this invention has the following advantages compared with the prior art: This invention adds an ultrasonic device to the water washing section of the pre-treatment roughening line for solder resist, utilizing its high-frequency vibration and cavitation effect to thoroughly remove impurities and microparticles from the PCB surface, reducing residue caused by incomplete cleaning. It replaces traditional screen cleaning paper with a lint-free cloth made of a composite material of polyester and polypropylene fibers, eliminating debris generated by screen cleaning paper fiber shedding. Replacing the metal dust removal roller in the screen printing exposure stage with a polycarbonate plastic support avoids metal wear debris and debris formed by electrostatic adsorption of human skin flakes, thus effectively reducing the generation of debris under the solder resist in multiple key stages. By addressing the core causes of debris generation in the solder resist process, this invention effectively solves the problem of debris easily appearing under the solder resist layer in traditional processes, ensuring that the PCB is free of debris under a 40X microscope. This meets customers' stringent requirements for product appearance quality, improves the overall quality of the PCB, reduces product scrap rates due to debris under the solder resist, and increases the production pass rate.

[0017] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the structural steps of the present invention. Detailed Implementation

[0019] 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. The specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention. 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.

[0020] This invention provides, for example Figure 1 The method for reducing debris under PCB solder mask, as shown, includes the following steps: Inspect the condition of the water washing section of the pre-treatment roughening line for solder resist; After inspection and confirmation, the water washing section of the pre-treatment roughening line for solder resist is equipped with an ultrasonic device to wash the PCB for 3-5 minutes, thus achieving PCB cleaning. After cleaning the PCB surface, prepare a lint-free cloth made of polyester fiber and polypropylene fiber composite material. During the solder resist cleaning process, wipe the screen with the lint-free cloth in the order from the center to the edge, and replace the lint-free cloth in time after each use. After completing the solder resist cleaning operation, the screen printing exposure stage begins. The original metal dust removal roller is removed and replaced with a polycarbonate plastic bracket that is compatible with the equipment. After completing the above-mentioned steps of solder resist pretreatment, screen cleaning, and silkscreen exposure, the PCB is inspected.

[0021] The ultrasonic device is set to a frequency of 20-40kHz and a power of 100-300W to wash the PCB with water for 3-5 minutes. Specifically, ultrasound in this frequency range can generate suitable high-frequency vibrations. Combined with a power output of 100-300W, it can create a strong cavitation effect during the washing process. Tiny bubbles are continuously generated in the liquid and burst instantly, releasing a huge impact force. This force can penetrate deep into the tiny gaps and holes on the PCB surface, completely removing attached impurities, tiny particles, and residual contaminants.

[0022] A 3-5 minute water wash duration strikes a balance between cleaning effectiveness and production efficiency: too short a time may result in incomplete removal of impurities, failing to achieve the desired cleanliness; too long a time will increase production time and slow down the overall process. A continuous 3-5 minute wash at a frequency of 20-40kHz and a power of 100-300W ensures that impurities on the PCB surface are fully removed, providing a clean base for the subsequent solder mask process, while also adapting to the pace of industrial production. This avoids slowing down the overall production process due to the cleaning step and effectively reduces the problem of residual debris under the solder mask caused by incomplete pretreatment cleaning.

[0023] When washing the PCB, the water temperature in the washing tank is controlled at 30-40℃. Specifically, water temperature affects the viscosity of the liquid and the intensity of the cavitation effect. In the range of 30-40℃, the viscosity of water is moderate, which can ensure that ultrasound can propagate effectively in the liquid and make the cavitation effect (the generation and collapse of bubbles in the liquid) more active. The impact force generated when the bubbles collapse is stronger, which can more efficiently remove impurities and tiny particles attached to the PCB surface, especially those contaminants with strong adhesion.

[0024] Meanwhile, this temperature range will not adversely affect the material and performance of the PCB itself, avoiding the deformation of the PCB substrate or damage to the surface treatment layer that may be caused by excessively high water temperature. It also prevents the problems of reduced cleaning efficiency and incomplete removal of impurities when the water temperature is too low. By controlling the water temperature at 30-40℃, it can work synergistically with the frequency (20-40kHz), power (100-300W), and 3-5 minutes of water washing time of the ultrasonic device to further improve the cleanliness of the PCB surface, laying a more reliable foundation for reducing the residue of impurities in the subsequent solder mask process.

[0025] The cleanroom cloth needs to be cleaned before use to remove any fibers and impurities that may remain on the cloth surface. The size of the cleanroom cloth is 20cm×20cm-30cm×30cm. Specifically, this size of cleanroom cloth is easy for operators to hold with one hand, allowing for flexible control of the force and range when wiping the screen. It is especially suitable for fine wiping of different areas of the screen (including the center and edges), avoiding unstable grip and uneven wiping due to an excessively large cloth surface, or frequent replacement and increased operational complexity due to an excessively small cloth surface.

[0026] From a cleaning coverage perspective, the 20cm×20cm-30cm×30cm size matches the common screen mesh dimensions well, ensuring that a single wipe can cover the main area of ​​the screen mesh, reducing repeated wiping and improving cleaning efficiency, when wiping from the center to the edge. At the same time, this size provides sufficient cleaning area, and combined with the requirement to replace the cloth promptly after each use, it effectively avoids secondary contamination caused by excessive impurities on the cloth surface, further reducing the risk of fiber residue. Combined with the properties of the cleanroom cloth itself, a composite material of polyester and polypropylene fibers, it maximizes its role in preventing fiber shedding and efficient cleaning, providing a reliable guarantee for reducing debris in the solder resist process.

[0027] Before installation, the surface of the polycarbonate plastic bracket needs to be wiped with a lint-free cloth dampened with isopropyl alcohol. The thickness of the polycarbonate plastic bracket is 2-5mm. Specifically, before installation, the surface of the polycarbonate (PC) plastic bracket should be wiped with a lint-free cloth dampened with isopropyl alcohol. This step is to thoroughly remove dust, oil, mold release agent residue, and other impurities that may have adhered to the bracket during production, storage, and transportation. Isopropyl alcohol, as a highly volatile and effective cleaning organic solvent, can quickly dissolve and remove these contaminants without leaving any residue on the bracket surface. This prevents impurities caused by an unclean bracket surface from being carried into the screen printing exposure process and thus contaminating the PCB surface.

[0028] Meanwhile, setting the thickness of the polycarbonate plastic bracket to 2-5mm is a reasonable choice after comprehensively considering the bracket's structural stability and usability. A thickness of 2-5mm ensures the bracket has sufficient mechanical strength to support the PCB and resist minor collisions and friction during production, ensuring stable support for the PCB. It also avoids problems such as increased bracket weight and decreased compatibility with equipment space caused by excessive thickness. This allows for precise matching of the installation dimensions of the screen printing exposure equipment, ensuring a perfect fit between the replaced bracket and the equipment, without affecting the normal operation of the original process. Combined with the cleaning operation of wiping the surface with isopropyl alcohol, this reduces the risk of debris generation from both the cleanliness and structural reliability aspects of the bracket, further improving the process improvement effect.

[0029] When inspecting the PCB, the inspection scope covers the entire surface of the PCB, including corners and areas with dense wiring. Specifically, when inspecting a PCB, the inspection area covers its entire surface, with particular attention paid to corners and areas with dense circuitry, in order to fully verify the effectiveness of process improvements in controlling debris under the solder mask.

[0030] PCB corners and edges are prone to contact with equipment edges or transmission devices during production, which may leave behind tiny scratches or contaminants. Densely packed circuit areas, with their complex wiring and narrow gaps, are even more susceptible to contamination if previous cleaning processes were inadequate. Undetected contamination in these areas not only affects the PCB's appearance but may also pose potential risks such as short circuits during subsequent use.

[0031] By conducting a comprehensive inspection of the entire surface, with a particular focus on corners and areas with dense wiring, we can ensure that no foreign matter is missed. This allows us to accurately determine whether improvements made to processes such as solder mask pretreatment, screen cleaning, and silkscreen exposure are truly effective. As a result, we can guarantee that every PCB meets our customers' stringent requirement of being free of foreign matter under a 40X microscope, further improving product reliability and yield.

[0032] The ultrasonic device has multiple supports for placing PCBs in its cleaning tank, with a spacing of 5-10cm between the supports. Specifically, the multiple support brackets can adapt to the needs of industrial mass production, completing the cleaning process of more PCBs within the same time period, reducing the cleaning time of a single PCB, and improving the overall production rhythm. The 5-10cm spacing provides sufficient space for ultrasonic action and water circulation: too small a spacing will cause PCBs to block each other, affecting the uniform propagation of ultrasonic waves and the efficiency of water flow in removing impurities, which may result in incomplete cleaning in some areas; too large a spacing will waste cleaning tank space and reduce the processing capacity per unit time.

[0033] A spacing of 5-10cm ensures sufficient liquid flow space around each PCB, allowing the cavitation effect generated by the ultrasonic waves to act evenly on the front and back surfaces and edges of each PCB. At the same time, it facilitates the timely removal of impurities from the PCB surface by the water flow during the cleaning process, which are then captured by the filter components in the cleaning tank, such as the filter screen, preventing impurities from circulating and adhering between PCBs. In conjunction with the cleaning parameters and water temperature control of the ultrasonic device, the cleanliness of the PCB surface is guaranteed in terms of both batch processing efficiency and cleaning uniformity, further reducing the risk of residual debris under the solder mask.

[0034] The ultrasonic device is equipped with a detachable filter assembly in its cleaning tank, which uses a 500-800 mesh stainless steel filter screen. Specifically, 500-800 mesh stainless steel filters have a suitable pore size: they can effectively filter out tiny impurities, such as particles with a diameter of about 15-25 micrometers, ensuring that the water remains clean after cleaning; however, the pore size is not too fine, which would cause excessive water flow resistance, affecting the propagation of ultrasonic waves and the normal circulation of water in the cleaning tank. At the same time, stainless steel has good corrosion resistance and mechanical strength, can adapt to long-term use in water washing environments, and is not easily damaged by water flow impact or cleaning fluid corrosion.

[0035] The detachable design allows operators to regularly remove the filter components for cleaning or replacement, preventing the filter from becoming clogged due to impurities and ensuring the continuous effectiveness of the filtration function. This filter component works synergistically with the cleaning parameters and water temperature control of the ultrasonic device to reduce the possibility of impurities remaining from the perspective of water purification, providing a more comprehensive guarantee for the thorough cleaning of the PCB surface.

[0036] In the water washing section of the pretreatment roughening line for solder resist, the ultrasonic device is installed 1-1.5m away from the inlet of the water washing section, and 2-3 sets of staggered ultrasonic transducers are set along the PCB transmission direction. Specifically, in the water washing section of the pre-solder resist roughening line, the ultrasonic device is installed 1-1.5m from the entrance of the water washing section. This distance is designed to allow the PCB to undergo preliminary water washing and wetting before entering the ultrasonic action area, loosening surface impurities and facilitating efficient ultrasonic cleaning. If the installation position is too close, the PCB surface may not be sufficiently wetted, resulting in strong impurity adhesion and increasing the cleaning load on the ultrasonic waves; if it is too far, it will prolong the overall processing flow and reduce production efficiency.

[0037] Simultaneously, 2-3 sets of staggered ultrasonic transducers are arranged along the PCB transport direction to form an all-round, dead-angle-free ultrasonic field. The staggered distribution design avoids acoustic wave interference between transducers, thus preventing cleaning blind spots. This ensures that the front, back, and edges of the PCB are covered by uniform and strong ultrasonic vibrations during transport. Each set of transducers works together, and through the cavitation effect generated by high-frequency vibration, it gradually deepens the peeling force on impurities in tiny gaps and holes on the PCB surface. Especially for those small particles with strong adhesion, multiple sets of staggered transducers can form a continuous and multi-angle impact force, further improving the thoroughness of impurity removal. In conjunction with the frequency, power, and water washing time parameters of the ultrasonic device, it provides a cleaner PCB surface for subsequent solder mask processes.

[0038] The surface of the polycarbonate plastic support is treated with an antistatic coating, with a coating thickness of 5-10 μm and a surface resistance controlled at 10 Ω·cm. 6 -10 9 Ω; Specifically, a coating thickness of 5-10 μm ensures the formation of a complete and uniform conductive film, covering every area of ​​the stent surface, without increasing surface roughness or degrading mechanical properties due to excessive coating thickness. This coating thickness provides stable conductivity, maintaining the stent surface resistivity at around 10 ohms. 6 -10 9 The ideal resistance range of Ω ensures that the resistance value can effectively release static electricity generated on the surface of the support due to friction, preventing the accumulation of static electricity and the formation of a strong electric field, while also avoiding unnecessary conductive risks due to excessively low resistance, thus ensuring production safety.

[0039] This treatment makes it difficult for the plastic support surface to attract dust, human skin flakes, and other tiny impurities from the air, cutting off a major source of impurities at the screen printing exposure stage. Combined with the smooth surface and chemical corrosion resistance of the polycarbonate material used in the support itself, this further improves the control of impurities under solder mask, ensuring that the PCB appearance quality meets the customer's strict requirement of no impurities under a 40X microscope.

[0040] Working Principle: Inspect the condition of the washing section of the pre-treatment ultra-roughening line for solder resist; after inspection and confirmation, install an ultrasonic device on the washing section of the pre-treatment ultra-roughening line to wash the PCB for 3-5 minutes to achieve PCB cleaning; after cleaning the PCB surface, prepare a lint-free cloth made of polyester fiber and polypropylene fiber composite material. In the solder resist screen washing stage, wipe the screen with the lint-free cloth in the order from the center to the edge, and replace the lint-free cloth in time after each use; after completing the solder resist screen washing operation, proceed to the screen printing exposure stage, remove the original metal dust removal roller, and replace it with a polycarbonate plastic bracket that is compatible with the equipment; after completing the above-mentioned pre-treatment of solder resist, screen washing, screen printing exposure, etc., inspect the PCB.

[0041] In addition, the present invention also provides a terminal device. The process method for reducing debris under PCB solder mask involved in this embodiment is mainly applied to the terminal device, which can be a PC, portable computer, mobile terminal or other device with display and processing functions.

[0042] Specifically, the terminal device may include a processor (e.g., CPU), a communication bus, a user interface, a network interface, and memory. The communication bus is used to enable communication between these components; the user interface may include a display screen or an input unit such as a keyboard; the network interface may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface); the memory may be high-speed RAM or stable non-volatile memory, such as disk storage, and may also optionally be a storage device independent of the aforementioned processor.

[0043] The memory stores a readable storage medium, which stores a program for reducing debris under PCB solder mask. The processor can call the program for reducing debris under PCB solder mask stored in the memory and execute the process manufacturing method for reducing debris under PCB solder mask provided in this embodiment of the invention.

[0044] Understandably, a readable storage medium can be a tangible device capable of holding and storing instructions for use by an instruction execution device. A computer-readable storage medium can be, for example—but not limited to—an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination thereof. The computer-readable storage medium as used herein is not to be construed as a transient signal itself, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0045] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0046] Computer program instructions used to perform operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0047] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A manufacturing method for reducing debris under PCB solder mask, characterized in that, Includes the following steps: Inspect the condition of the water washing section of the pre-treatment roughening line for solder resist; After inspection and confirmation, the water washing section of the pre-treatment roughening line for solder resist is equipped with an ultrasonic device to wash the PCB for 3-5 minutes, thus achieving PCB cleaning. After cleaning the PCB surface, prepare a lint-free cloth made of polyester fiber and polypropylene fiber composite material. During the solder resist cleaning process, wipe the screen with the lint-free cloth in the order from the center to the edge, and replace the lint-free cloth in time after each use. After completing the solder resist cleaning operation, the screen printing exposure stage begins. The original metal dust removal roller is removed and replaced with a polycarbonate plastic bracket that is compatible with the equipment. After completing the above-mentioned steps of solder resist pretreatment, screen cleaning, and silkscreen exposure, the PCB is inspected.

2. The manufacturing method for reducing debris under PCB solder mask according to claim 1, characterized in that: The ultrasonic device is set to a frequency of 20-40kHz and a power of 100-300W to wash the PCB with water for 3-5 minutes.

3. The manufacturing method for reducing debris under PCB solder mask according to claim 1, characterized in that: When washing the PCB, the water temperature in the washing tank is controlled at 30-40℃.

4. The manufacturing method for reducing debris under PCB solder mask according to claim 1, characterized in that: The cleanroom cloth needs to be cleaned before use to remove any fibers and impurities that may remain on the cloth surface. The size of the cleanroom cloth is 20cm×20cm-30cm×30cm.

5. The manufacturing method for reducing debris under PCB solder mask according to claim 1, characterized in that: Before installation, the surface of the polycarbonate plastic bracket should be wiped with a lint-free cloth dampened with isopropyl alcohol. The thickness of the polycarbonate plastic bracket is 2-5mm.

6. The manufacturing method for reducing debris under PCB solder mask according to claim 1, characterized in that: When inspecting the PCB, the inspection scope covers the entire surface of the PCB, including corners and areas with dense wiring.

7. The manufacturing method for reducing debris under PCB solder mask according to claim 1, characterized in that: The ultrasonic device has multiple supports for placing PCBs inside its cleaning tank, with a spacing of 5-10cm between the supports.

8. The manufacturing method for reducing debris under PCB solder mask according to claim 1, characterized in that: The ultrasonic device has a detachable filter assembly in its cleaning tank, which uses a 500-800 mesh stainless steel filter.

9. The manufacturing method for reducing debris under PCB solder mask according to claim 1, characterized in that: In the water washing section of the pretreatment and roughening line for solder resist, the ultrasonic device is installed 1-1.5m away from the inlet of the water washing section, and 2-3 sets of staggered ultrasonic transducers are set along the PCB transmission direction.

10. The manufacturing method for reducing debris under PCB solder mask according to claim 5, characterized in that: The surface of the polycarbonate plastic support is treated with an antistatic coating, with a coating thickness of 5-10 μm and a surface resistance controlled at 10 Ω. 6 -10 9 Ω.

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