A package substrate cleaning process

Abstract

The application provides a packaging substrate cleaning process and relates to the technical field of packaging substrate production.The application comprises the following steps: S1, controlling the first side of the negative pressure cleaning cover to be attached to the first side surface of the packaging substrate body for one-time negative pressure suction; S2, after a predetermined time of one-time negative pressure suction, controlling the second side of the negative pressure cleaning cover to be attached to the second side surface of the packaging substrate body for two-time negative pressure suction; and S3, controlling the first side of the negative pressure cleaning cover and the second side of the negative pressure cleaning cover to be alternately attached to the surface of the packaging substrate body, and controlling one-time negative pressure suction and two-time negative pressure suction to be alternately performed in the process of gas cleaning or liquid cleaning of the packaging substrate. The application significantly improves the cleaning uniformity of micropores and large thickness-diameter ratio pores, effectively reduces the problems of poor conduction and reliability failure caused by copper-free holes and residual dirt on the hole walls of the packaging substrate.

Description

Technical Field

[0001] This invention relates to the field of packaging substrate manufacturing technology, and in particular to a packaging substrate cleaning process. Background Technology

[0002] In the packaging substrate manufacturing process, after drilling and desmearing, the ceramic micro powder and ceramic fragments inside the through holes and blind holes of the substrate need to be deeply cleaned. At present, the mainstream cleaning methods are divided into two categories: static immersion cleaning and single-sided spray negative pressure cleaning. The supporting equipment mostly adopts a cleaning tank structure with the substrate placed horizontally, relying on unidirectional liquid flushing or single negative pressure adsorption to remove impurities in the holes.

[0003] In existing cleaning processes, the cleaning medium inside the vias is updated slowly, and air bubbles remain trapped in the channels for a long time, forming cleaning dead zones. It is difficult to completely remove contaminants from the inside of micropores and vias with large aspect ratios. Especially for multilayer thick boards with large aspect ratio vias, the depth of the vias on the surface is greater, and the cleaning medium cannot flow effectively inside the vias. Poor cleaning effect inside the vias leads to the inability to carry out the subsequent copper plating process effectively. Ultimately, it is easy to cause unreliability problems such as no copper in the vias, plating voids, and substrate delamination, which makes it difficult to meet the high-precision clean production requirements of high-density multilayer micro-via packaging substrates. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a packaging substrate cleaning process that significantly improves the cleaning uniformity of microvias and high aspect ratio holes; effectively reduces poor conductivity and reliability failures caused by copper-free holes and residual contaminants on the hole walls.

[0005] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0006] A packaging substrate cleaning process uses a packaging substrate preparation device, which includes a cleaning tank, a packaging substrate cleaning device, and a driving device for controlling the movement of the packaging substrate cleaning device. The packaging substrate cleaning device includes a limiting component for limiting the packaging substrate body, and negative pressure cleaning hoods located on both sides of the limiting component. The limiting component and the negative pressure cleaning hoods are both vertically arranged. The process includes the following steps: S1, controlling the negative pressure cleaning hood on the first side to adhere to the first side surface of the packaging substrate body for a first negative pressure suction; S2, after a predetermined time of the first negative pressure suction, controlling the negative pressure cleaning hood on the second side to adhere to the second side surface of the packaging substrate body for a second negative pressure suction; S3, repeating steps S1 and S2, controlling the negative pressure cleaning hood on the first side and the negative pressure cleaning hood on the second side to alternately adhere to the surface of the packaging substrate body, and controlling the first negative pressure suction and the second negative pressure suction to alternate during the gas cleaning or liquid cleaning process of the packaging substrate.

[0007] Preferably, it also includes two sets of control devices for controlling the horizontal reciprocating movement of the negative pressure cleaning hood, the first set of control devices being fixedly connected to the negative pressure cleaning hood on the first side, and the second set of control devices being fixedly connected to the negative pressure cleaning hood on the second side.

[0008] Preferably, the control device includes a control rod fixedly connected to the negative pressure cleaning hood, a telescopic component is provided on the first side of the control rod, and a guide component is provided on the second side of the control rod.

[0009] Preferably, the guide assembly is a one-way pumping telescopic rod, and the control rod sidewall is fixed with a strip-shaped liquid outlet located outside the limiting assembly. The one-way pumping telescopic rod includes a suction pipe and a pumping pipe. The pumping pipe is connected to the strip-shaped liquid outlet, and the suction pipe is located on the side of the limiting assembly away from the strip-shaped liquid outlet.

[0010] Preferably, the one-way pumping telescopic rod includes a housing, inside which a control piston is sealed and slidable. The control piston divides the interior of the housing into a first chamber and a second chamber. Both the first chamber and the second chamber are connected to pumping pipes with two built-in one-way valves. The pumping pipes that pump out liquid are connected to the pumping outlet pipe.

[0011] Preferably, elastic buffer components are provided on both sides of the control piston. The elastic buffer components include an elastic buffer piston and an elastic reset element. After the control piston moves outward, the elastic buffer piston continues to move outward to achieve continuous pumping of the clear liquid.

[0012] Preferably, the negative pressure cleaning hood includes an outer hood and an inner hood located inside the outer hood. At least two inner hoods are provided, and a negative pressure suction pipe is connected to the top of each inner hood.

[0013] Preferably, the limiting component includes a U-shaped positioning plate, the inner wall surface of the U-shaped positioning plate has a limiting groove, the outer side of the U-shaped positioning plate is detachably connected to a limiting plate, and both sides of the limiting plate and the U-shaped positioning plate are provided with annular sealing rings, which are adapted to the edge of the inner wall of the outer cover.

[0014] Preferably, the inner cover has a strip-shaped liquid inlet at the bottom and a strip-shaped liquid spray nozzle at the top, and a circulating filter device with the strip-shaped liquid inlet and the strip-shaped liquid spray nozzle connected in series is provided between the outer cover and the inner cover.

[0015] Preferably, the cleaning tank includes a dry cleaning tank and a wet cleaning tank. The dry cleaning tank is equipped with a gas spray gun, which is used to flush the particulate matter on both sides of the limiting and packaging substrate.

[0016] The beneficial effects of this invention are as follows:

[0017] Compared with existing technologies, this invention effectively solves the problems of untimely replenishment of the solution in the hole, difficulty in flowing through the narrow through hole, bubble retention, and dead corners of residual pollutants in traditional single-sided cleaning and static soaking. The vertical structure can avoid the problem of secondary adhesion of impurities caused by horizontal placement of the substrate, and significantly improve the cleaning uniformity of micro-holes and holes with large thickness-to-diameter ratio. It effectively reduces the problems of poor conductivity and reliability failure caused by copper-free holes and residual dirt on the hole walls of the packaging substrate. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the packaging substrate fabrication equipment of the present invention.

[0019] Figure 2 For the present invention Figure 1 A top-view structural diagram.

[0020] Figure 3 For the present invention Figure 2 A schematic diagram of the AA-direction cross-section structure.

[0021] Figure 4 This is a schematic diagram showing the working state of the negative pressure cleaning cover and the limiting component of the present invention.

[0022] Figure 5 This is a schematic diagram of the internal structure of the negative pressure cleaning cover of the present invention.

[0023] Figure 6 This is a schematic diagram of the limiting component structure of the present invention.

[0024] Figure 7 This is a schematic diagram of the internal structure of the housing of the present invention.

[0025] Figure 8 This is a process flow diagram of the present invention.

[0026] In the diagram: 100, cleaning tank; 110, dry cleaning tank; 120, wet cleaning tank; 200, drive unit; 210, horizontal drive assembly; 211, bottom positioning platform; 220, vertical drive assembly; 300, packaging substrate cleaning device; 310, negative pressure cleaning hood; 311, outer hood; 312, inner hood; 313, negative pressure suction pipe; 314, circulating filtration device; 3141, strip spray nozzle; 3142, strip... 320. U-shaped liquid inlet; 321. Limiting assembly; 322. U-shaped positioning plate; 323. Sealing ring; 324. Limiting plate; 400. Control device; 410. Telescopic assembly; 420. Control rod; 431. Guide assembly; 432. Housing; 4311. First chamber; 4312. Second chamber; 433. Control piston; 434. Elastic buffer assembly; 435. Pumping rod; 436. Pumping pipeline; 500. Encapsulation substrate. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0028] See attached document Figure 1 - Appendix Figure 8 A packaging substrate cleaning process is disclosed, using a packaging substrate preparation device. The packaging substrate preparation device includes a cleaning tank 100, which includes a dry cleaning tank 110 and a wet cleaning tank 120. A gas spray gun is provided in the dry cleaning tank 110, and the gas spray gun is used to rinse the particulate matter on both sides of the limiting packaging substrate 500.

[0029] The system features separate dry and wet cleaning tanks. First, high-pressure airflow is used for dry cleaning to remove large particles of dust and loose debris from the surface and orifices. Then, negative pressure circulation is used for wet cleaning to complete deep cleaning inside the orifices, achieving a graded cleaning process of dry cleaning followed by wet cleaning.

[0030] By using graded cleaning, large particles of impurities can be prevented from directly entering the wet cleaning channels, causing micropore blockage and scratches on the hole walls; the dry and wet dual-station design adapts to the cleaning needs of different processes after drilling and after descaling, and is suitable for the entire process of cleaning the packaging substrate; it significantly improves the overall cleanliness of the substrate and reduces reliability defects such as copper-free holes, plating voids, CAF failure, and delamination blistering from the source.

[0031] The equipment also includes a substrate cleaning device 300 and a drive device 200 for controlling the movement of the substrate cleaning device 300. The drive device 200 includes a bottom positioning platform 211 for mounting the substrate cleaning device 300 and the control device 400, a horizontal drive component 210 for controlling the horizontal movement of the bottom positioning platform 211, and a vertical drive component 220 for controlling the vertical movement of the bottom positioning platform 211. The horizontal drive component 210 and the vertical drive component 220 work together to control the substrate cleaning device 300 and the control device 400 to move the substrate 500 between the dry cleaning tank 110 and the wet cleaning tank 120, thereby achieving multi-stage cleaning treatment of the substrate 500.

[0032] The packaging substrate cleaning apparatus 300 includes a limiting component 320 that limits the packaging substrate 500, and negative pressure cleaning hoods 310 located on both sides of the limiting component 320. Both the limiting component 320 and the negative pressure cleaning hoods 310 are arranged vertically. A negative pressure suction space is formed inside the negative pressure cleaning hoods 310. The contact surface between the negative pressure cleaning hoods 310 and the packaging substrate 500 is elastic and can be completely sealed and adhered to the surface of the packaging substrate 500. After sealing and adhering, a negative pressure is formed inside the negative pressure cleaning hoods 310, allowing dry or wet media to pass through the through holes on the surface of the packaging substrate 500, thus cleaning the residual substances in the through holes. This is especially suitable for deep cleaning of small-sized through holes on the surface of a thicker packaging substrate 500.

[0033] The vertically arranged negative pressure cleaning hood 310 and limiting component 320 can prevent the extracted particles from depositing; during the bidirectional reciprocating suction process, the particles will be discharged to the outside with the flow of the medium, which can prevent the particles from adhering to the surface of the packaging substrate 500 to the greatest extent and avoid secondary pollution caused by bidirectional alternating suction.

[0034] The cleaning process of the packaging substrate 500 of this invention includes the following steps:

[0035] S1. Control the negative pressure cleaning cover 310 on the first side to adhere to the first side surface of the packaging substrate 500. At this time, the negative pressure cleaning cover 310 on the second side separates from the second side surface of the packaging substrate 500 and performs a negative pressure suction. The medium inside the through hole of the packaging substrate 500 flows in the first direction to complete a cleaning.

[0036] S2. After the negative pressure suction reaches the preset time, the negative pressure cleaning cover 310 on the second side is controlled to adhere to the second side surface of the packaging substrate 500, and a second negative pressure suction is carried out. At this time, the negative pressure cleaning cover 310 on the first side separates from the first side surface of the packaging substrate 500; the medium inside the through hole of the packaging substrate 500 flows in the second direction in the opposite direction to complete the second cleaning.

[0037] The duration of a single negative pressure suction is selected from 14S to 20S based on the thickness and aperture of the encapsulation substrate, and the negative pressure value of the suction is selected from -20KPa to -90KPa based on the thickness and aperture of the encapsulation substrate.

[0038] S3. Control the first side negative pressure cleaning cover 310 and the second side negative pressure cleaning cover 310 to alternately adhere to the surface of the packaging substrate 500; during the gas dry cleaning or liquid wet cleaning process, the first negative pressure suction and the second negative pressure suction alternately cycle, and the medium flow direction switches back and forth, forming a high-speed bidirectional flushing of the inner wall of the through hole, effectively removing impurities attached to the inner wall of the through hole, and minimizing impurity residue.

[0039] This invention employs a dual-sided vertical negative pressure cleaning hood paired with a limiting component to vertically clamp and position the substrate. Relying on the alternating contact and suction of the two negative pressure cleaning hoods, the cleaning medium (cleaning liquid or clean gas) alternately penetrates the through-holes from both sides of the substrate, achieving dynamic replacement of the medium within the holes. Through sequential bidirectional alternating suction, it overcomes the drawbacks of traditional static immersion cleaning, such as medium retention, air bubble accumulation within the holes, and the inability to remove impurities, thus meeting the process requirements for deep double-sided cleaning of the through-holes of the packaging substrate.

[0040] In summary, this invention effectively solves the problems of untimely replenishment of the cleaning solution in the holes, bubble retention, and dead corners with residual contaminants that exist in traditional single-sided cleaning and static soaking. The vertical structure can avoid the problem of secondary adhesion of impurities caused by the horizontal placement of the substrate, and significantly improve the cleaning uniformity of micropores and holes with large thickness-to-diameter ratios. The equipment is compatible with both dry gas cleaning and wet liquid cleaning, making it more versatile and effectively reducing the problems of poor conductivity and reliability failure caused by copper-free holes and residual dirt on the hole walls of the packaged substrate.

[0041] The dry cleaning and wet cleaning process of this invention is as follows: After the substrate is vertically clamped and positioned, it is first sent into the dry cleaning tank. The negative pressure hood alternately suctions and circulates 3-5 times to complete the blowing and adsorption of dry particles. After sampling and testing, if the large particle residue on the board surface meets the standard, the equipment will transfer the entire substrate to the wet cleaning tank. During the transfer process, nitrogen is used for isolation and blowing, and the dry and wet media pipelines are completely independent and do not communicate with each other. In the wet cleaning stage, the substrate is cleaned 4-6 times by partitioned negative pressure combined with cavity spray circulation. After the wet cleaning is completed, the substrate is automatically transferred to the drying station and dried with hot air at 60-80℃ for 10-15 minutes to control the moisture content of the substrate to ≤0.05% before being transferred to the next process. At the same time, the two working conditions are equipped with different configurations: the dry cleaning is equipped with dustproof filter cotton and dry friction sealing ring, while the wet cleaning is equipped with hydrophilic filter components and water-resistant silicone sealing ring.

[0042] Furthermore, the equipment is also equipped with two sets of control devices 400 for controlling the horizontal reciprocating movement of the negative pressure cleaning hood 310. The first set of control devices 400 is fixedly connected to the first side negative pressure cleaning hood 310 and drives the first side negative pressure cleaning hood 310 to perform horizontal linear movement; the second set of control devices 400 is fixedly connected to the second side negative pressure cleaning hood 310 and drives the second side negative pressure cleaning hood 310 to perform horizontal linear movement. Multiple sets of negative pressure cleaning hoods 310 and limiting components 320 can be set. A single set of control devices 400 can drive multiple sets of negative pressure cleaning hoods 310 to move horizontally synchronously. Multiple sets of negative pressure cleaning hoods 310 synchronously adhere to the surface of the corresponding packaging substrate 500, completing the negative pressure suction cleaning operation of multiple packaging substrates 500 in one go.

[0043] Two independent control devices manage the negative pressure cleaning covers on both sides, enabling independent horizontal displacement, independent pressing and bonding, and independent reset of the negative pressure covers on both sides. The bonding stroke on one side can be adaptively adjusted according to the flatness of the board surface and the amount of warpage of the substrate, ensuring that the actions of the negative pressure covers on both sides do not interfere with each other and are independently controllable.

[0044] This structure further overcomes the defects of poor adhesion, single-sided air leakage, and board surface damage caused by the synchronous movement of the integrated negative pressure cover; the independent drive mode can adapt to packaging substrates with different shapes and warpages, ensuring good sealing and uniform pressing for each bonding, eliminating the problem of negative pressure attenuation and inconsistent cleaning force caused by sealing leakage, and greatly improving the consistency of cleaning quality of batch products.

[0045] Specifically, the control device 400 includes a control rod 420 fixedly connected to the negative pressure cleaning hood 310. A telescopic assembly 410 is mounted on one side of the control rod 420, and a guide assembly 430 is mounted on the other side. The telescopic assembly provides a telescopic driving force for the negative pressure cleaning hood to fit horizontally, and works with the guide assembly to linearly limit and guide the control rod, constraining the negative pressure cleaning hood to move smoothly only in the horizontal direction, eliminating deviations such as offset, tilt, and jamming during the displacement process.

[0046] This structure ensures high parallelism and precise alignment when the negative pressure cleaning hood is attached to the board surface, preventing local sealing failure and circuit damage caused by oblique attachment; it also improves the stability of the reciprocating operation of the negative pressure hood, reduces equipment noise and failure rate, and meets the precision cleaning requirements of high-precision thin packaging substrates.

[0047] More specifically, the guide component 430 uses a one-way pumping telescopic rod, and the control rod 420 has a strip-shaped liquid outlet on its side wall, which is arranged outside the limiting component 320. The one-way pumping telescopic rod includes a suction pipe and a pumping pipe. The pumping pipe is connected to the strip-shaped liquid outlet, and the suction pipe is arranged on the side of the limiting component 320 away from the strip-shaped liquid outlet. When the one-way pumping telescopic rod reciprocates, it can form a continuous and directional cleaning liquid flow before and after the limiting component 320, promote the full flow of liquid inside the wet washing tank 120, and realize the real-time renewal of the cleaning medium. At the same time, it guides the flow of fine particles overflowing from the periphery of the limiting component 320, carrying away the fine debris and preventing particles from accumulating around the packaging substrate 500 and causing negative pressure cleaning failure.

[0048] This solution integrates the guide telescopic rod with the pump structure. The telescopic rod itself extends and retracts to automatically draw and discharge liquid. The suction pipe draws the cleaning medium from the tank and then sprays it out evenly through the pump outlet pipe and strip-shaped outlet. This forms a surrounding liquid flow around the negative pressure cleaning hood, which helps to flush away impurities accumulated on the process edges and sealing blind areas of the substrate.

[0049] This solution enables structural reuse, eliminating the need for additional spray pipes, simplifying the overall structure and reducing modification costs; the strip-shaped liquid outlet sprays a uniform liquid flow, which can specifically remove dust and ceramic micro-particles accumulated on the edges of the substrate and in sealed gaps, eliminating edge dead corners in traditional cleaning; a single mechanism simultaneously achieves the dual functions of mechanical guidance and auxiliary rinsing, significantly improving the comprehensiveness of cleaning.

[0050] More specifically, the one-way pumping telescopic rod includes a housing 431, inside which a control piston 432 is sealed and slidably assembled. A pumping rod 434 is fixed to the side wall of the control piston 432, and the pumping rod 434 passes through the housing 431 and is rigidly connected to the control rod 420. The control piston 432 divides the inner cavity of the housing 431 into a first chamber 4311 and a second chamber 4312. The first chamber 4311 and the second chamber 4312 are respectively connected to two pumping pipes 435 with built-in one-way valves. When the control piston 432 slides back and forth, one of the pumping pipes 435 continuously pulses to draw liquid into the first chamber or the second chamber, and the other pumping pipe 435 continuously pulses to pump the liquid out of the chamber. All the pumping pipes 435 used for drainage are connected to the pump outlet pipe.

[0051] It should be noted that when the control piston moves to the left, the volume of the first chamber on the left is compressed, and the liquid inside is pumped to the strip outlet through the liquid outlet check valve. The volume of the second chamber on the right expands, and the cleaning liquid in the tank is drawn in through the liquid inlet check valve. When the control piston moves to the right, the volume of the second chamber on the right is compressed to realize the pumping of liquid, and the volume of the first chamber on the left expands to complete the suction of liquid. Throughout the piston's reciprocating stroke, the two chambers alternately complete the suction and pumping actions.

[0052] The elastic buffer components on both sides of the piston have a delayed release function. After the control rod stops horizontal feeding and the main piston no longer actively moves, the elastic buffer piston will slowly extend and retract outward, slowly pressurizing the chambers that are currently in the liquid storage state, so that the chambers that have just completed liquid storage will continuously discharge liquid in small amounts. During the complete reciprocating cycle of the piston, the first chamber and the second chamber pump liquid alternately. With the superposition of the delayed continuous liquid discharge effect of the elastic buffer components, the overall strip-shaped liquid outlet continuously sprays out cleaning liquid without interruption. It is not required that the two chambers shrink in volume and discharge liquid at the same time.

[0053] By relying on the reciprocating sliding of the piston to change the volume of the two chambers, and with the cooperation of the one-way valve, the liquid can be automatically drawn in and discharged within the extension stroke, forming an uninterrupted continuous pumping circulation, ensuring that a stable liquid flow is always sprayed out during the reciprocating motion of the negative pressure hood; the self-pumping is completed by the mechanical kinetic energy, eliminating the need for a separate water pump and saving energy; the alternating discharge of the two chambers eliminates the interruption of liquid flow and pressure fluctuations, ensuring a stable edge auxiliary rinsing force; the one-way valve prevents liquid backflow and avoids reverse contamination of the clean plate surface by dirty liquid in the tank.

[0054] Furthermore, elastic buffer assemblies 433 are mounted on both sides of the control piston 432. Each elastic buffer assembly 433 includes an elastic buffer piston and an elastic reset element. The elastic reset element can be a reset spring sleeved on the outside of the pumping rod 434. The control piston 432 moves rapidly with the control rod 420, and the elastic buffer assemblies 433 on both sides slowly extend outward after being compressed. During the continuous and slow extension of the elastic buffer assemblies 433, the cleaning fluid inside the first chamber 4311 and the second chamber 4312 is continuously sprayed out from the strip-shaped outlet. Throughout the entire reciprocating motion of the control piston 432, the cleaning fluid is continuously pumped in one direction, forming a directional and stable liquid flow before and after the limiting assembly 320. This drives the liquid inside the wet washing tank 120 to fully circulate and renew, directionally discharging particulate impurities from both sides of the packaging substrate 500, ensuring the cleanliness of subsequent negative pressure cleaning.

[0055] This structure utilizes the time-delay energy storage characteristics of the elastic buffer component. After the piston stops moving, the elastic reset element continues to push the buffer piston to move slowly, extending the pumping time and enabling the negative pressure cover to continue spraying liquid outward during the static bonding stage.

[0056] This design solves the problem of instantaneous flow interruption of traditional pump fluid when the machine starts and stops, extends the flushing time of edge dead corners, and enhances the effect of impurity removal; the elastic buffer can also absorb the reciprocating impact of the piston, reduce equipment wear, extend the service life of the whole machine, and improve operational stability.

[0057] Specifically, the negative pressure cleaning hood 310 includes an outer hood 311 and multiple sets of inner hoods 312 arranged inside the outer hood 311; different inner hoods 312 correspond to different aperture areas, ensuring that the aperture size of the area covered by a single inner hood 312 remains consistent; the top of the inner hood 312 is connected to a negative pressure suction pipe 313. This solution adopts a double-layer hood structure with multiple sets of independent inner hoods, which can achieve independent negative pressure suction in different zones according to the differences in the aperture distribution of the substrate, and separately adjust the negative pressure suction for large and small aperture areas.

[0058] The structure includes an inner cover 312. In this case, the through holes on the surface of the packaging substrate are completely covered by the inner cover 312. The outer cover 311 does not need to play the role of sealing negative pressure suction. The purpose of the outer cover 311 is to adapt to the contour size of the packaging substrate and to realize the installation and fixation of the inner cover 312.

[0059] For a packaging substrate with fixed surface via positions, the outer cover 311 and the inner cover 312 can be completely fixed to form a fixed negative pressure suction and positioning structure. When replacing the packaging substrate, the outer cover 311 and the inner cover 312 can be replaced as a whole to meet the negative pressure cleaning requirements of different fixed types of packaging substrates.

[0060] For customized, small-batch packaging substrates, the outer cover 311 and the inner cover 312 can adopt a modular design. Depending on the required size and aperture distribution on the surface of the packaging substrate, an inner cover 312 of a suitable size can be specifically fixed at different positions inside the outer cover 311. Optional accessories are also available. Figure 5 The two sets of symmetrical inner covers 312 shown can also be designed horizontally or in other ways as needed. The outer cover 311 and the inner cover can be fixed with bolts to maintain relative stability.

[0061] This structure solves the industry problems of large-hole flow interception, insufficient suction of micro-holes, and uneven cleaning flow of large and small holes in integrated negative pressure hoods; multi-zone independent negative pressure can match the high-density layout of micro-holes and large-diameter holes on the packaging substrate, accurately match the cleaning intensity to different areas, and greatly improve the uniformity of cleaning the whole board.

[0062] The division of independent negative pressure zones in this invention is based on the core standard of the pre-set aperture distribution in the substrate layout. Before production, the substrate engineering data is imported, and the board surface is divided into independent areas of small hole area (0.15mm~0.3mm through hole) and large hole area (0.3mm~1.0mm through hole) according to the drawings. The equipment has pre-stored multiple specifications of internal covers of corresponding sizes, and the corresponding specifications of the internal covers are matched according to the aperture of each area. The alignment method uses a fixed positioning target on the edge of the substrate and a U-shaped positioning plate of the limiting component to achieve a unified benchmark. The drive device is equipped with a vision positioning module to capture the target coordinates and complete the automatic alignment of the negative pressure cleaning cover zones. The board surface scanning and recognition program can be started first to collect the size and coordinates of the holes of the entire board in real time. The system automatically generates the zone boundary, matches the corresponding internal cover specifications, and completes the alignment and bonding, realizing adaptive zoned negative pressure cleaning of substrates without drawings.

[0063] Furthermore, the limiting component 320 includes a U-shaped positioning plate 321, with a limiting groove on the inner wall of the U-shaped positioning plate 321. The packaging substrate 500 is positioned and fixed by being inserted into the limiting groove around its perimeter. A limiting plate 323 is detachably mounted on the outer side of the U-shaped positioning plate 321, forming a barrier to limit the packaging substrate 500 from the outer notch. Both the limiting plate 323 and the U-shaped positioning plate 321 are equipped with annular sealing rings 322 on both sides. The sealing rings 322 are adapted to the inner edge of the outer cover 311. The outer cover 311, in conjunction with the sealing rings 322, achieves sealing and positioning, ensuring the accurate overall installation position of the negative pressure cleaning cover 310.

[0064] It should be noted that the thickness of the inner cover 312 is greater than the wall thickness of the outer cover 311, and the annular protrusion of the inner cover 312 is elastic, ensuring that the inner cover 312 can fit tightly against the surface of the packaging substrate 500, thus ensuring stable operation of the negative pressure suction.

[0065] In summary, the U-shaped positioning plate combined with a detachable limiting plate enables rapid clamping and positioning of the substrate. The annular sealing ring ensures complete circumferential sealing after the negative pressure cover is attached, isolating the liquid in the tank from the negative pressure cleaning chamber and ensuring the negative pressure chamber is airtight. This structure is simple to assemble, disassemble, and maintain; the complete circumferential seal prevents negative pressure leakage and liquid flow short circuits, ensuring stable negative pressure in each zone; simultaneously, it prevents floating impurities in the tank from entering the cleaning area through gaps, preventing secondary contamination of the substrate.

[0066] Furthermore, the inner cover 312 has a strip-shaped liquid inlet 3142 at the bottom and a strip-shaped liquid spray nozzle 3141 at the top; a circulating filter device 314 is installed between the outer cover 311 and the inner cover 312, and the circulating filter device 314 is connected in series with the strip-shaped liquid inlet 3142 and the strip-shaped liquid spray nozzle 3141. During the negative pressure suction operation, the cleaning liquid is filtered in a closed loop by the vertically connected inlet and outlet in conjunction with the circulating filter device, which intercepts, settles and purifies the sewage and solid particles extracted from the hole in real time, and the purified clean liquid is returned to participate in the cleaning cycle.

[0067] The circulating filtration device 314 includes a pipeline with a built-in filter structure and a pump body. The pipeline connects the strip-shaped liquid inlet 3142 and the strip-shaped liquid spray nozzle 3141. The pump body works continuously to achieve directional delivery of liquid. The filter structure is a detachable filter unit. A detachable filter element can be installed in the strip-shaped liquid inlet 3142 to achieve continuous filtration of ceramic micronized particles. After a certain period of filtration, the filter element is replaced to meet the requirements of continuous filtration.

[0068] It should also be noted that the negative pressure suction pipe 313 does not significantly affect the normal circulation filtration of the circulation filtration device 314 while it is suctioning under negative pressure. Although the inner cover 312 is under negative pressure, the strip-shaped liquid inlet 3142 and the strip-shaped liquid spray nozzle 3141 are both located inside the inner cover, and the pressure difference between their two ends is small. The liquid can circulate normally between the strip-shaped liquid inlet 3142 and the strip-shaped liquid spray nozzle 3141 to achieve filtration circulation.

[0069] The aforementioned negative pressure suction pipe 313 can not only be installed in the attached Figure 5 The top position shown can also be configured as an L-shaped or U-shaped bend, connected to the side wall or bottom of the inner cover 312, to avoid fluid interference caused by the suction direction of the negative pressure suction pipe 313 being opposite to the circulation suction of the circulation filter device 314 under extreme circumstances.

[0070] This structure can intercept ceramic micro-particles in real time, completely eliminating the problems of impurity backflow and secondary scratches on the hole walls caused by bidirectional alternating suction; the cleaning solution is recycled, reducing the consumption of cleaning solution and lowering production costs; the medium inside the cavity is continuously purified, maintaining high cleanliness throughout the process, effectively improving the yield of hole wall cleaning of the packaging substrate, and ensuring the production reliability of subsequent copper plating and electroplating processes.

[0071] Finally, it should be noted that the diameter of the vias on the surface of this packaging substrate is typically 0.15mm to 1.0mm. For the 0.15mm to 0.3mm small via area, the suction negative pressure is increased (-60KPa to -90KPa), and for the 0.3mm to 1.0mm large via area, the suction negative pressure is decreased (-20KPa to -60KPa) to solve the problem of uneven flow between large and small vias. Furthermore, this equipment cleans the micropores of the packaging substrate, with via sizes ranging from only 0.15mm to 1.0mm. These tiny vias exhibit extremely high fluid resistance, and the liquid is sprayed from the strip-shaped nozzles within the cavity. The flow rate is greater than the flow rate of the medium drawn out by the negative pressure suction pipe, so it will not affect the normal filtration. At the same time, the negative pressure suction pipe controls the internal enclosure to be in a negative pressure state, which can continuously draw the cleaning liquid from the outside of the encapsulation substrate inward. The fluid impulse brought by the negative pressure suction is weak, and there is no obvious counteracting effect with the directional flow of the medium formed by the circulation filtration. The fluid resistance between the two is negligible and will not weaken the unidirectional replacement effect of the cleaning medium in the hole. It can stably realize the circulation cleaning function of continuously drawing out impurities in the hole and continuously replenishing fresh cleaning medium.

[0072] It should be further noted that the present invention cleans the through holes on the surface of the multilayer packaging substrate after multilayer hot pressing. Before the multilayer packaging substrate is hot-pressed and bonded, the blind holes are cleaned in advance by the existing immersion cleaning process. The cleaning of the blind holes can refer to the existing technology and is not a technical problem that the present invention needs to address.

[0073] The present invention will be further described below with reference to specific embodiments.

[0074] This application classifies holes into two categories: small holes (0.15mm–0.3mm) and large holes (0.3mm–1.0mm). The overall duration of a single negative pressure suction cycle ranges from 14 to 20 seconds, with a total negative pressure range of -20 kPa to -90 kPa. The small hole region has high fluid resistance, so the negative pressure is limited to -60 kPa to -90 kPa to enhance media penetration. The large hole region has high flow capacity, so the negative pressure is limited to -20 kPa to -60 kPa to avoid erosion and damage to the hole walls. An industry-standard 8-layer FC-BGA multilayer packaging substrate was selected as the test substrate. Three sets of embodiments were set up corresponding to the lower limit, middle value, and upper limit of the implementation range of this invention. After cleaning, 1000 through-holes were uniformly tested to collect statistical defect data in each set. Specific details are as follows:

[0075] Example 1

[0076] A general-purpose 8-layer FC-BGA multilayer packaging substrate is selected, with 0.18mm small holes and 0.7mm large holes distributed on the board surface. The lower limit of the single negative pressure suction time range is 14s. The lower limit values ​​of the negative pressure matching in each zone are: -60KPa negative pressure in the 0.18mm small hole area and -20KPa negative pressure in the 0.7mm large hole area. After continuous suction on one side for 14s, the negative pressure cover on the other side is automatically switched. The single cleaning cycle is set to perform 5 bidirectional alternating suctions, with a 2s pressure relief buffer reserved at the end of each cycle.

[0077] Defect detection results: 1000 holes were randomly inspected. In the small hole area, there were 22 voids in the plating and no defects of no holes or copper. In the large hole area, there were 6 voids in the plating and no defects of no holes or copper.

[0078] Example 2

[0079] A general-purpose 8-layer FC-BGA multilayer packaging substrate is selected, with 0.22mm small holes and 0.6mm large holes distributed on the board surface. The single negative pressure suction time is selected as the midpoint of the range, 17s. The negative pressure of the zones is selected as the midpoint: -75KPa negative pressure is used in the 0.22mm small hole area, and -40KPa negative pressure is used in the 0.6mm large hole area. After the suction on one side is completed in 17s, the other side cavity is switched. The single cleaning cycle is set to 4 rounds of bidirectional alternating suction, with a 2s pressure relief buffer reserved at the end of each round.

[0080] Defect detection results: 1000 holes were randomly inspected. In the small hole area, there were 14 voids in the plating and no defects of no holes or copper. In the large hole area, there were 3 voids in the plating and no defects of no holes or copper.

[0081] Example 3

[0082] A general-purpose 8-layer FC-BGA multilayer packaging substrate is selected, with 0.28mm small holes and 0.9mm large holes distributed on the board surface. The single negative pressure suction time is selected to be the upper limit of the range of 20s. The negative pressure of the zone adopts the limit value of the range: -90KPa negative pressure in the 0.28mm small hole area and -60KPa negative pressure in the 0.9mm large hole area. After continuous suction with high negative pressure on one side for 20s, the direction is reversed. A single cleaning cycle is set to 6 rounds of bidirectional alternating suction, with a 2s pressure relief buffer reserved at the end of each round.

[0083] Defect detection results: 1000 holes were randomly inspected. In the small hole area, there were 3 voids in the plating and no defects of no holes or copper. In the large hole area, there was 1 void in the plating and no defects of no holes or copper.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. 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 packaging substrate cleaning process, using a packaging substrate preparation device, characterized in that: The packaging substrate preparation equipment includes a cleaning tank (100), a packaging substrate cleaning device (300), and a driving device (200) for controlling the movement of the packaging substrate cleaning device (300). The packaging substrate cleaning device (300) includes a limiting component (320) for limiting the packaging substrate plate (500), and also includes negative pressure cleaning hoods (310) located on both sides of the limiting component (320). The limiting component (320) and the negative pressure cleaning hoods (310) are both arranged vertically. Includes the following steps: S1. Control the negative pressure cleaning cover (310) on the first side to adhere to the first side surface of the packaging substrate (500) and perform a negative pressure suction once; S2. After a predetermined time of negative pressure suction, the negative pressure cleaning cover (310) on the second side is controlled to adhere to the second side surface of the packaging substrate (500) for a second negative pressure suction. S3. Repeat steps S1 and S2; control the alternation of one negative pressure suction and two negative pressure suction. It also includes two sets of control devices (400) for controlling the horizontal reciprocating movement of the negative pressure cleaning hood (310). The first set of control devices (400) is fixedly connected to the negative pressure cleaning hood (310) on the first side, and the second set of control devices (400) is fixedly connected to the negative pressure cleaning hood (310) on the second side. The control device (400) includes a control rod (420) fixedly connected to the negative pressure cleaning hood (310). A telescopic component (410) is provided on the first side of the control rod (420), and a guide component (430) is provided on the second side of the control rod (420). The guide assembly (430) is a one-way pumping telescopic rod. The control rod (420) has a strip-shaped liquid outlet fixed on its side wall, located outside the limiting assembly (320). The one-way pumping telescopic rod includes a suction pipe and a pumping pipe. The pumping pipe is connected to the strip-shaped liquid outlet. The suction pipe is located on the side of the limiting assembly (320) away from the strip-shaped liquid outlet. The negative pressure cleaning hood (310) includes an outer hood (311) and an inner hood (312) located inside the outer hood (311). At least two inner hoods (312) are provided, and a negative pressure suction pipe (313) is connected to the top of the inner hood (312).

2. The packaging substrate cleaning process according to claim 1, characterized in that, The one-way pump telescopic rod includes a housing (431), inside which a control piston (432) is sealed and slides. The control piston (432) divides the inside of the housing (431) into a first chamber (4311) and a second chamber (4312). The first chamber (4311) and the second chamber (4312) are both connected to pumping pipes (435) with two built-in one-way valves. The pumping pipes (435) that pump out liquid are all connected to the pump outlet pipe.

3. The packaging substrate cleaning process according to claim 2, characterized in that, Both sides of the control piston (432) are provided with elastic buffer components (433). The elastic buffer components (433) include an elastic buffer piston and an elastic reset element. After the control piston (432) moves outward, the elastic buffer piston continues to move outward to realize the continuous pumping out of the clear liquid.

4. The packaging substrate cleaning process according to claim 1, characterized in that, The limiting component (320) includes a U-shaped positioning plate (321), the inner wall surface of the U-shaped positioning plate (321) is provided with a limiting groove, and a limiting plate (323) is detachably connected to the outer side of the U-shaped positioning plate (321). Both the limiting plate (323) and the U-shaped positioning plate (321) are provided with annular sealing rings (322), and the sealing rings (322) are adapted to the inner wall edge of the outer cover (311).

5. The packaging substrate cleaning process according to claim 1, characterized in that, The inner cover (312) is provided with a strip-shaped liquid inlet (3142) at the bottom and a strip-shaped liquid spray nozzle (3141) at the top. A circulating filter device (314) connecting the strip-shaped liquid inlet (3142) and the strip-shaped liquid spray nozzle (3141) is provided between the outer cover (311) and the inner cover (312).

6. A packaging substrate cleaning process according to any one of claims 1-5, characterized in that, The cleaning tank (100) includes a dry cleaning tank (110) and a wet cleaning tank (120). A gas spray gun is provided in the dry cleaning tank (110) to flush the particulate matter on both sides of the limiting and packaging substrate (500).

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