A soldering apparatus for MLO packaged devices

Abstract

The application discloses a welding device for MLO packaging devices and relates to the technical field of semiconductor packaging welding equipment, which comprises a guiding module, a tin planting module and a die hot-pressing module, the guiding module is used for conveying a substrate and guiding the substrate to pass through the tin planting module and the die hot-pressing module in sequence, the tin planting module comprises a lower die arranged directly above the guiding module, a positioning hole array, an infrared positioning module and a tin bead processing assembly, the tin bead processing assembly is slidingly connected in the lower die, the die hot-pressing module is located directly above the tin planting module and comprises a hot-pressing die, and the hot-pressing die is provided with hot-pressing points corresponding to the positioning hole array one by one at the bottom. The application guarantees coplanarity after welding.

Description

Technical Field

[0001] This invention relates to the technical field of semiconductor packaging welding equipment, and in particular to a welding apparatus for MLO packaged devices. Background Technology

[0002] MLO (Multi-Module Loop) packaging devices are semiconductor packaging products that integrate multiple functional modules onto the same substrate. One side is connected to the wafer via pins, while the other side is fixed to the PCB board via soldering. Their core advantage lies in achieving miniaturization and high-performance integration of electronic devices. The soldering equipment for MLO packaging devices is specifically designed to complete the soldering connection to the PCB board. Precise control of solder supply, positioning, and the thermal melting process is required to ensure the stability and reliability of the soldering.

[0003] In existing technologies, the soldering of MLO packaged devices to PCB boards mainly adopts ball-mounting soldering process. The specific process is as follows: first, solder paste is printed on the PAD (pad) of the MLO using a steel sheet and balls are placed on it, and the solder paste is melted to form thin solder joints; then, solder paste is printed on the PCB board, the MLO is mounted, and nitrogen reflow soldering is used to remelt the solder paste and solder balls to form solder joints.

[0004] During the solder joint formation process, excessive solder content after remelting of solder paste and solder balls can cause the solder joint to deform easily when heated due to surface tension, resulting in inconsistent sinking heights and severely affecting the coplanarity of the solder joint. At the same time, the solder joint height is difficult to control precisely, which not only reduces product yield but also interferes with the accuracy of subsequent tests, ultimately affecting the overall reliability of the product. Summary of the Invention

[0005] This application provides a welding apparatus for MLO packaged devices, which ensures coplanarity after welding.

[0006] This application provides a welding apparatus for MLO packaged devices, which adopts the following technical solution: A soldering apparatus for an MLO packaged device includes a guiding module, a soldering module, and a mold hot pressing module. The guiding module is used to transport a substrate and guide the substrate through the soldering module and the mold hot pressing module in sequence. The soldering module includes a lower mold, a positioning hole array, an infrared positioning module, and a solder ball processing component disposed directly above the guiding module. The solder ball processing component is slidably connected inside the lower mold. The mold hot pressing module is located directly above the soldering module and includes a hot pressing mold. The bottom of the hot pressing mold is provided with hot pressing points that correspond one-to-one with the positioning hole array.

[0007] Preferably, the guiding module includes a side rail, a toothed chain drive unit, and a transmission platform. The toothed chain drive unit drives the transmission platform to move linearly along the side rail through tooth meshing transmission. The transmission platform is provided with a positioning base for supporting the substrate.

[0008] Preferably, a lifting mechanism is provided below the positioning base. The lifting mechanism is used to adjust the distance between the positioning base and the transmission platform, and the output end of the lifting mechanism is fixedly connected to the positioning base.

[0009] Preferably, the solder ball processing assembly includes a housing, a drive motor, and a lead screw transmission mechanism. The drive motor is fixed to one side of the lower mold, and the lead screw transmission mechanism includes a lead screw connected to the output end of the drive motor and a threaded sleeve fixed on the housing. The lead screw and the threaded sleeve form a helical transmission pair.

[0010] Preferably, the bottom of the housing is provided with brush fibers and a scraper. The brush fibers are distributed at the bottom edge of the housing to form a double-sided covering structure. The scraper is located between two rows of brush fibers and has a conical bottom structure that contacts the surface of the lower mold.

[0011] Preferably, the brush bristles are bonded to a detachable mounting strip, which is fixed to the bottom of the housing by a snap fastener or bolt.

[0012] Preferably, the housing is provided with a temporary storage cavity and a replenishment channel. The temporary storage cavity is connected to the replenishment channel through a beveled guide structure. The outlet of the replenishment channel is located between the scraper and the brush fibers and corresponds one-to-one with the positioning hole array.

[0013] Preferably, the housing is further provided with a negative pressure channel, the inlet of which is located between the scraper and the brush fibers, the outlet of which is connected to the input end of the negative pressure pump, and the output end of which is connected to the temporary storage chamber.

[0014] Preferably, the negative pressure channel and the supplementary channel are staggered at the bottom of the housing, and the distance between the inlet of the negative pressure channel and the outlet of the supplementary channel is 3-5mm.

[0015] Preferably, the hot pressing point at the bottom of the hot pressing mold is integrally formed and has a semi-circular positioning groove at its end, the opening of the positioning groove facing the substrate, and the bottom of the hot pressing point has a hemispherical structure.

[0016] In summary, this application has the following beneficial effects: 1. To address the functional challenge of precise alignment between substrate transport and solder placement points, this invention further optimizes the process by incorporating a mechanical and optical dual-positioning collaborative structure for the guiding module and the solder placement module. The guiding module ensures transport accuracy through a gear chain drive and adjusts the height using a lifting mechanism. The solder placement module uses infrared positioning to calibrate the position and a positioning hole array to define the solder ball path. The two modules are arranged vertically to form a collaborative closed loop of transport, positioning, and solder placement, achieving millimeter-level alignment between the substrate and the solder ball, preventing solder placement misalignment, and thus ensuring coplanarity after soldering.

[0017] 2. To further optimize the collaborative operation of solder ball spreading, compaction, replenishment, and recycling, this invention sets up a progressive collaborative structure of "brush-scraper-channel-negative pressure" inside the solder ball processing component. The brush spreads the solder balls, the scraper precisely compacts them, the replenishment channel replenishes solder instantly, and the negative pressure channel recycles redundancy. The staggered layout of the channels avoids interference, and the sliding trajectory of each component and the shell is deeply coordinated. This achieves a simultaneous improvement in solder uniformity, solder utilization rate, and operation efficiency, reducing waste and defects.

[0018] 3. To address the functional issue of poor matching between the soldering and hot pressing processes, this invention further optimizes the process by incorporating a one-to-one correspondence between the soldering module's positioning hole array and the hot pressing points of the mold's hot pressing module. During soldering, the positioning holes define the solder ball positions, and during hot pressing, the hot pressing points precisely cover the solder joints. Furthermore, the hot pressing point positioning grooves are adapted to the shape of the solder balls, ensuring complete alignment between the preceding and following process points. This achieves precise connection between the solder balls from placement to hot melting and forming, significantly improving the coplanarity of the solder joints.

[0019] 4. To further optimize the process flow and address the issue of mismatched process rhythms, this invention also incorporates a coordinated mechanism between the automatic conveying of the guide module and the operation rhythm of each module. The conveying speed driven by the toothed chain is matched with the sliding stroke of the solder ball processing component and the lifting and heating time of the hot pressing module. The system triggers a unified signal to link the start and stop of each module, thereby achieving seamless connection between substrate conveying, soldering, and hot pressing, avoiding process interruptions, and improving the efficiency of mass production.

[0020] 5. To further optimize the device and address the issue of poor compatibility across different specifications, this invention also incorporates a global multi-component collaborative adaptation structure. This structure includes a guide module lifting mechanism for height adjustment, a flexible brush for solder ball processing components to adapt to different hole arrays, a replaceable lower mold to adapt to different solder joint distributions, and a hot-pressing point to accommodate solder balls with slight dimensional deviations. The complementary and collaborative functions of each component enable a single device to adapt to multiple MLO packaged devices, thereby reducing the cost of device changeover and debugging.

[0021] 6. To further optimize the hot pressing process and address the issues of heat waste and substrate damage, the present invention also incorporates a collaborative optimization of the hot pressing module. The heating module transfers heat evenly through the hot pressing plate, and the hemispherical structure of the hot pressing point and the positioning groove concentrate heat. Furthermore, the centralized hot pressing precisely targets the solder balls, thereby achieving a synergistic effect of improved thermal efficiency and reduced overall substrate heating. This ensures solder joint formation while preventing thermal damage to the substrate. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the welding device in this embodiment; Figure 2 This is a schematic diagram of the internal structure of the tin-coating module in this embodiment; Figure 3 This is a schematic diagram of the overall structure of the solder bead processing component in this embodiment; Figure 4 This is a schematic diagram of the internal structure of the solder bead processing component in this embodiment; Figure 5 This is a schematic diagram of the overall structure connecting the shell and the bristle fibers in this embodiment; Figure 6 This is a partial cross-sectional view of the shell in this embodiment; Figure 7 This is a schematic diagram of the internal structure of the mold hot pressing module in this embodiment. Figure 8 This is a schematic diagram of the connection structure between the hot pressing mold and the hot pressing point in this embodiment. Figure 9 This is a schematic diagram of the overall structure of a single hot-pressing point in this embodiment; Explanation of reference numerals in the attached drawings: 1. Chassis; 2. Guide module; 201. Side rail; 202. Transmission platform; 203. Positioning base; 3. Soldering module; 301. Lower mold; 302. Mounting bracket; 303. Rectangular groove; 304. Positioning hole; 305. Infrared positioning module; 4. Mold hot pressing module; 401. Limiting bracket; 402. Hydraulic rod; 403. Hot pressing plate; 404. Hot pressing mold; 405. Hot pressing point; 406. Positioning groove; 5. Solder ball treatment component; 501. Housing; 502. Drive motor; 503. Lead screw; 504. Sleeve; 505. Brush fiber; 506. Scraper; 507. Temporary storage chamber; 508. Supplement channel; 509. Negative pressure channel; 5010. Negative pressure pump; 5011. Output pipe. Detailed Implementation

[0023] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0024] Example This invention discloses a welding apparatus for MLO packaged devices, such as... Figure 1 As shown, the system includes a chassis 1, and inside the chassis 1 is a guide module 2 for placing and guiding the substrate. Specifically, the guide module 2 includes a side rail 201 disposed inside the chassis 1. Inside the side rail 201 is a toothed chain drive unit and a transmission platform 202 connected to the output end of the toothed chain drive unit. Under the action of the toothed chain drive unit, the transmission platform 202 realizes transmission between the two side rails 201.

[0025] Furthermore, the upper surface of the transmission platform 202 is provided with a positioning base 203 for positioning the substrate, and an electric telescopic rod is provided between the lower surface of the positioning base 203 and the transmission platform 202 to realize the up and down lifting of the positioning base 203 on the transmission platform 202, so as to adjust the relative height of the substrate on the positioning base 203.

[0026] Under the action of the guide module 2, a guide path is formed on the substrate inside the chassis 1. Inside the chassis 1 and along the guide path, the soldering module 3 and the mold hot pressing module 4 are arranged in sequence. A precise transport path is constructed through guide module 2, enabling automated transfer of the substrate from soldering to hot-pressing. Within guide module 2, the toothed chain drive unit built into the side rail 201 utilizes the toothed meshing transmission characteristics, transmitting power through the precise engagement of the toothed chain and sprocket, driving the transmission platform 202 to move smoothly and linearly along the side rail 201. Compared to traditional roller chain drives, the toothed chain meshing gap is smaller, ensuring the synchronous accuracy of substrate transport. The electric telescopic rod between the positioning base 203 and the transmission platform 202 can flexibly adjust the substrate height according to process requirements, adapting to both soldering height and the pressure stroke of the hot-pressing module 4.

[0027] like Figure 1 and Figure 2As shown, the soldering module 3 and the mold hot pressing module 4 are both located directly above the guide module 2. Specifically, the soldering module 3 includes a lower mold 301 and a mounting bracket 302 mounted on the chassis 1. The lower mold 301 has a rectangular groove 303 inside, and the rectangular groove 303 has positioning holes 304 arranged in an array inside. The positioning holes 304 are correspondingly positioned with the solder balls. The mounting bracket 302 has an infrared positioning module 305 inside for monitoring the relative position of the positioning holes 304 and the solder balls. The position of the substrate is monitored by the infrared positioning module 305. When the substrate is positioned directly below the lower mold 301, the solder balls in the lower mold 301 pass through the positioning holes 304 and are positioned and bonded to the solder paste applied to the surface of the substrate.

[0028] like Figure 1 and Figure 2 As shown, high-precision bonding of solder balls to the substrate is achieved through infrared positioning and an array of positioning holes 304. The soldering module 3 and the guide module 2 are arranged vertically to ensure that the substrate transported by the transmission platform 202 accurately reaches the area directly below the lower mold 301. The array of positioning holes 304 within the rectangular groove 303 of the lower mold 301 is designed strictly according to the solder joint distribution of MLO packaged devices, precisely matching the size of the solder balls and providing a fixed guiding channel to prevent solder ball misalignment during the soldering process. The infrared positioning module 305 is integrated into the mounting bracket 302, monitoring the relative position of the substrate and the positioning holes 304 in real time. Combined with the high precision of the toothed chain drive of the guide module 2, this forms a dual guarantee of "mechanical transport positioning + infrared optical calibration".

[0029] like Figure 1 and Figure 2 As shown, when the substrate reaches the designated position, the system trigger signal causes the solder ball in the lower mold 301 to fall along the positioning hole 304, accurately adhering to and initially bonding with the pre-coated solder paste on the substrate surface. The adhesiveness of the solder paste can temporarily fix the position of the solder ball, laying a solid foundation for subsequent mold hot-press welding. The entire process achieves standardized control of the solder placement position and quantity, eliminating the random errors of manual solder placement.

[0030] like Figure 1 and Figure 2 As shown, in addition to its core soldering function, the soldering module 3 has three unexpected advantages. First, it reduces solder waste and contamination. The array positioning holes 304 can precisely control the fall of individual solder balls, preventing them from scattering. Compared with traditional spray-applied soldering, the solder utilization rate is increased by more than 30%. At the same time, the rectangular groove 303 can collect the fallen excess solder balls, preventing solder from contaminating the internal transmission components of the chassis 1.

[0031] Secondly, it is highly stable in high-temperature working conditions. The infrared positioning module 305 is installed in a staggered manner with the lower mold 301, keeping it away from the high-temperature radiation of the subsequent hot pressing module, avoiding the impact of high temperature on positioning accuracy. No additional cooling device is required, which simplifies the structure and reduces energy consumption.

[0032] Third, it facilitates process traceability and debugging. The 304 positioning hole array layout can be quickly adapted to MLO devices with different solder joint distributions by changing the lower mold 301 with different hole specifications. Infrared positioning data can be recorded in real time, which facilitates the investigation of the causes of soldering defects and shortens the process debugging cycle. In addition, the guiding effect of the positioning holes 304 can reduce the impact force when solder balls and solder paste are attached, avoid solder joint defects caused by solder paste splashing, and further improve the soldering yield.

[0033] like Figure 3 and Figure 4 As shown, a solder ball processing component 5 is slidably disposed in the rectangular groove 303 of the lower mold 301. The solder ball processing component 5 is used to uniformly release solder balls, recover excess solder balls, and uniformly press the solder balls so that the solder balls are uniformly adhered to the solder paste applied to the substrate surface.

[0034] like Figure 3 and Figure 4 As shown, specifically, the solder ball processing assembly 5 includes a housing 501 that slides back and forth along the long side of the rectangular groove 303 and a drive motor 502 disposed on one side of the lower mold 301. The output end of the drive motor 502 is connected to a lead screw 503, which passes through a threaded sleeve 504 fixed on one side of the housing 501. Driven by the drive motor 502, the lead screw 503 rotates and causes the housing 501 to slide back and forth in the groove disposed on the side of the housing 501. Brush fibers 505 are disposed at the bottom of the housing 501 and inside the rectangular groove 303. The brush fibers 505 completely cover all the arrayed positioning holes 304, and the bottom of the brush fibers 505 is in contact with the upper surface of the rectangular groove 303 of the lower mold 301.

[0035] By replacing manual shaking operations with automated mechanical transmission, the solder ball spreading, recycling, and pressure application are integrated into a precise operation, overcoming the randomness of traditional manual operations. The solder ball processing component 5 uses a drive motor 502 as its power source. The output end of the drive motor 502 drives the lead screw 503 to rotate. The lead screw 503 and the threaded sleeve 504 on the side of the housing 501 form a helical transmission structure, which converts the rotational motion of the drive motor 502 into the linear reciprocating motion of the housing 501 along the long side of the rectangular groove 303. The sliding groove on the side of the housing 501 provides guidance and limit for the sliding, ensuring accurate and non-deviation-free motion trajectory. The brush fibers 505 at the bottom of the housing 501 completely cover the array positioning holes 304 and fit the upper surface of the rectangular groove 303. When the housing 501 slides back and forth, the brush can gently sweep the solder balls, so that the solder balls evenly fill the positioning holes 304 and cover the substrate solder paste. On the other hand, it can apply uniform pressure to the solder balls that fall on the solder paste, promote the tight bonding between the solder balls and the solder paste, and sweep the excess solder balls back into the rectangular groove 303 for recycling and reuse. The whole process does not require manual intervention and is compatible with the automated conveying rhythm of the guide module 2 mentioned above, forming a closed-loop control of the soldering process.

[0036] Compared to traditional manual shaking, this component offers more than three unexpected advantages and is deeply integrated with the overall performance of the device. First, it avoids solder paste contamination and solder joint failure. Manual shaking easily leads to solder paste splattering and substrate misalignment. The flexible contact of the brush fibers 505 ensures even solder application without damaging the solder paste coating on the substrate surface, while also avoiding oil and impurities from hand contact, reducing the risk of cold solder joints. Second, it extends the service life of the lower mold 301. Traditional shaking causes hard friction between solder balls and the inner wall of the mold, easily causing wear on the positioning holes 304. The flexible cleaning of the brush reduces the scraping of the positioning holes 304 by solder balls. Combined with excess solder ball recycling, it reduces the accumulation of impurities inside the mold, extending the mold maintenance cycle by more than 50%. Third, it adapts to various soldering requirements. The flexible nature of the brush fibers 505 eliminates the need to change the positioning hole 304 specifications. Only the speed and sliding stroke of the drive motor 502 need to be adjusted to adapt to positioning holes 304 with different array densities. This complements the height adjustment function of the electric telescopic rod mentioned earlier, improving the overall compatibility of the device. Fourth, it reduces energy consumption and noise. Compared with manual shaking, the uniform sliding driven by the motor has controllable energy consumption and low operating noise, which matches the low noise advantage of the gear chain drive mentioned above and meets the quiet requirements of precision manufacturing.

[0037] like Figure 5 and Figure 6As shown, the brush fibers 505 are arranged in two rows, positioned at the bottom edge of the housing 501, forming a "double-sided wrap-around" cleaning range that matches the reciprocating sliding trajectory of the housing 501 along the rectangular groove 303. When the housing 501 moves under the drive of the lead screw 503, the brush fibers on both sides can sweep the solder balls from both ends of the rectangular groove 303 towards the center, ensuring that the solder balls evenly fill all the array positioning holes 304 and efficiently sweeping excess solder balls to the center of the rectangular groove 303 for collection, preventing solder balls from accumulating at the edges. Furthermore, the brush fibers 505 are bonded to the mounting strip, which is detachable from the bottom of the housing 501. The brush fibers can be quickly replaced and cleaned without disassembling the entire solder ball processing assembly 5, adapting to the easily worn characteristics of the brush fibers without affecting the stability of the overall transmission structure of the device.

[0038] The two rows of edge bristles create a bidirectional cleaning force, which, compared to a single row of bristles, reduces the offset of solder balls above the positioning hole 304, improving the accuracy of the solder balls falling vertically into the positioning hole 304 by more than 25%, indirectly reducing the defect rate of subsequent hot-press soldering. In addition, the two rows of edge bristles can simultaneously clean the residual solder paste debris on the edge of the positioning hole 304 as they slide, preventing debris from accumulating and clogging the positioning hole 304. Compared to the traditional structure, this reduces the frequency of hole cleaning by more than 80%, extending the continuous operation time of the lower mold 301.

[0039] like Figure 6 As shown, a scraper 506 is provided at the bottom center of the housing 501. The scraper 506 is located between two rows of brush fibers 505, adapting to the reciprocating sliding trajectory of the housing 501 along the rectangular groove 303, forming a progressive operation process of "brush spreading - scraper 506 compaction - brush recycling". The bottom cross-section of the scraper 506 is a conical structure. The bottom of the scraper 506 contacts the upper surface of the rectangular groove 303 of the lower mold 301, serving both guiding and pressure functions. The conical tip can first contact the top of the solder ball, using the point force characteristic to accurately press the solder ball into the positioning hole 304, avoiding the solder ball displacement or compression of solder paste caused by planar scraping. As the housing 501 moves, the conical side can push the excess solder balls in the rectangular groove 303 to both sides, which are then recycled to the middle of the groove by the brush fibers 505 on both sides, achieving efficient cleaning of redundant solder balls. The bottom of the scraper 506 is in close contact with the upper surface of the rectangular groove 303, which ensures uniform pressure and thoroughly removes residual impurities from the groove surface. This complements the flexible cleaning of the brush fibers 505. Combined with the precision of infrared positioning and lead screw 503 transmission, it greatly improves the consistency of solder ball implantation.

[0040] In addition to its basic pressure application and cleaning functions, the 506 scraper structure has two unexpected advantages and is well-suited to the overall performance of the device.

[0041] Firstly, it avoids solder paste overflow and loss. The tapered structure's gradual pressure can control the solder ball embedding depth, preventing excessive pressure from causing solder paste to overflow from the positioning hole 304. Compared to flat scraping, the solder paste utilization rate is increased by more than 20%, while reducing the risk of overflowing solder paste clogging the positioning hole 304 after curing.

[0042] Secondly, it reduces the difficulty of equipment debugging. The collaborative structure of the scraper 506 and the brush bristles can reduce the error rate of a single component. Even if the brush bristles are slightly worn, the scraper 506 can still ensure the compaction effect of the solder balls, shortening the daily debugging and calibration time of the equipment.

[0043] like Figure 6 As shown, the housing 501 has a temporary storage cavity 507 for temporarily storing solder balls. The temporary storage cavity 507 has an inclined surface and is connected to a vertically arranged supplementary channel 508. There are several supplementary channels 508, which are arranged one-to-one with the positioning holes 304. The bottom outlet of the supplementary channel 508 is located between the scraper 506 and the brush fiber 505.

[0044] The temporary storage chamber 507 features a built-in inclined surface design, utilizing gravity to allow solder balls to naturally converge towards the replenishment channel 508. This achieves directional solder ball delivery without additional power, simplifying the structure and reducing energy consumption. Several replenishment channels 508 are vertically arranged and correspond one-to-one with the positioning holes 304, ensuring accurate solder supply and preventing solder ball waste. The bottom outlet of the replenishment channel 508 is located between the scraper 506 and the brush fibers 505. This arrangement is linked to the reciprocating sliding trajectory of the housing 501: when the housing 501 moves, the brush first spreads the solder balls, the scraper 506 compacts and clears excess material. If a solder ball is missing from the positioning hole 304, the solder balls in the temporary storage chamber 507 can immediately fall through the replenishment channel 508 to replenish the missing material. This design integrates the solder supply process into the solder ball processing component 5, eliminating the constraints of traditional external feeding devices and working in conjunction with the lead screw 503 drive and the brush scraper 506 structure to achieve integrated control of the entire soldering process.

[0045] In addition to the basic solder supply function, the above structure also improves the continuity of soldering. The real-time replenishment design avoids equipment downtime caused by traditional material supply interruptions, eliminates the need for frequent manual addition of solder balls, increases the continuous operation time of the soldering process, and adapts to the automated conveying rhythm mentioned above.

[0046] The one-to-one channel design allows for quantitative replenishment based on the requirements of the positioning hole 304. Combined with the cleaning function of the scraper 506 and brush bristles, it avoids the accumulation of solder balls caused by excessive feeding, thus reducing the solder waste rate compared to traditional batch feeding.

[0047] like Figure 6As shown, the housing 501 has an independently configured negative pressure channel 509 inside. The inlet of the negative pressure channel 509 is located between the scraper 506 and the brush fiber 505 and is offset from the supplementary channel 508. The outlet of the negative pressure channel 509 passes through the top of the housing 501 and is connected to the input end of the negative pressure pump 5010. The negative pressure pump 5010 is fixed on one side of the housing 501. The output end of the negative pressure pump 5010 is connected to the interior of the temporary storage chamber 507 through the output pipe 5011.

[0048] The negative pressure channel 509 is independently located inside the housing 501, with its inlet precisely positioned between the scraper 506 and the brush fibers 505. It is staggered from the replenishment channel 508, preventing the adsorption airflow from interfering with the falling solder balls in the replenishment channel 508 while accurately capturing excess solder balls, solder paste debris, and dust cleaned by the scraper 506. After the negative pressure pump 5010 starts, a stable negative pressure field is formed through the negative pressure channel 509, adsorbing excess material from the surface of the rectangular groove 303 into the channel. This material is then transported back to the temporary storage chamber 507 via the output pipe 5011, achieving the recycling and reuse of excess solder balls and the centralized treatment of impurities. The entire air circulation system is integrated within the housing 501, operating synchronously with the reciprocating sliding motion of the housing 501. In addition to the brush spreading and scraper 506 compaction and replenishment, a new "adsorption and recycling - circulating supply" stage is added, further improving the accuracy and resource utilization of the soldering operation.

[0049] In addition to its basic functions of recovering impurities and circulating solder balls, this structure has several advantages. First, it prevents secondary clogging of the positioning hole 304. The negative pressure adsorption instantly removes fine solder paste debris generated during the scraper 506's pushing process, reducing the clogging rate of the positioning hole 304 compared to relying solely on mechanical cleaning. This eliminates the need for frequent shutdowns for cleaning, ensuring continuous operation. Second, it stabilizes the solder ball placement environment. The negative pressure field suppresses the bouncing of solder balls caused by the sliding of the housing 501, preventing floating balls from affecting subsequent scraping accuracy. It also reduces solder paste splashing caused by airflow disturbance. Combined with the pressure applied by the conical scraper 506, this improves the solder ball placement success rate. Third, it reduces the risk of solder ball clumping in the temporary storage chamber 507. The recovered airflow causes slight movement of the solder balls within the temporary storage chamber 507, preventing long-term accumulation and clumping. This eliminates the need for an additional stirring device, simplifying the structure and reducing energy consumption.

[0050] like Figure 7 , Figure 8 and Figure 9As shown, the hot pressing module 4 includes a limiting bracket 401, on which a hydraulic rod 402 is fixedly installed. The bottom output end of the hydraulic rod 402 passes through the limiting bracket 401 and is connected to a hot pressing plate 403. A heating module is provided inside the hot pressing plate 403. The heating module preheats the hot pressing plate 403. The heat is transferred through the hot pressing plate 403 to the hot pressing mold 404 located at the bottom of the hot pressing plate 403. The bottom of the hot pressing mold 404 is provided with hot pressing points 405 distributed in a dot matrix. The hot pressing points 405 and the hot pressing mold 404 are integrally formed. The hot pressing points 405 are arranged one-to-one with the solder balls on the substrate. The bottom of the hot pressing points 405 is a hemispherical structure. The interior of the hot pressing points 405 is provided with a semi-circular positioning groove 406. The positioning groove 406 positions the solder balls on the substrate, so that the solder balls are melted and form a hemispherical structure, so that the solder balls change from point contact to surface contact.

[0051] The limiting bracket 401 provides stable support for the hydraulic rod 402, ensuring that the hydraulic rod 402 drives the hot press plate 403 to rise and fall vertically, preventing deviation during the hot pressing process. After the heating module preheats the hot press plate 403, the heat is evenly transferred to the hot press mold 404 through heat conduction, ensuring that the hot pressing temperature is stable and controllable, adapting to the temperature requirements of solder ball hot melting; typically 180-220℃. The dot-matrix hot pressing points 405 at the bottom of the hot press mold 404 correspond one-to-one with the solder balls on the substrate. The one-piece molding structure prevents breakage under stress during hot pressing. The hemispherical bottom and the built-in semi-circular positioning groove 406 form a double positioning, accurately wrapping the solder balls after soldering. This not only prevents the solder balls from shifting during hot melting, but also guides the solder balls to form a hemispherical shape after hot melting, changing the contact between the solder balls and the substrate from point contact to surface contact, greatly improving the welding area and conductivity stability. This works in conjunction with the infrared positioning and precise solder ball placement mentioned above to achieve a closed-loop process of "precise solder placement - hot pressing shaping".

[0052] In addition to basic hot-press welding functions, this module also reduces solder ball heat loss. The hemispherical positioning groove 406 can concentrate heat and reduce heat diffusion to the surroundings. Compared with planar hot pressing, the thermal efficiency is improved by more than 25%, while avoiding excessive melting and flow of solder balls, thus reducing material waste.

[0053] In addition, the semi-circular positioning groove 406 is designed to accommodate solder balls with irregular shapes, making it more compatible with solder balls with slight dimensional deviations. It eliminates the need for frequent replacement of the hot press mold 404. Combined with the multi-specification compatibility of the device mentioned above, it further expands the product's application range.

[0054] Then, the heat damage to the substrate is greatly avoided. The centralized hot pressing point 405 can accurately apply heat to the solder ball position, reduce the overall heated area of ​​the substrate, and reduce the risk of substrate deformation and aging due to high temperature. It is especially suitable for flexible substrates or heat-sensitive MLO devices.

[0055] Finally, to improve welding consistency, the one-piece hot pressing point 405 ensures uniform pressure and heat transfer efficiency at each point. Combined with the stable drive of the hydraulic rod 402, it can effectively avoid problems such as uneven weld depth and differences in conductivity caused by manual hot pressing, and significantly improve the product qualification rate of mass production.

[0056] Working principle: First, after starting the equipment, the operator places the substrate to be soldered, with solder paste printed on its upper surface, onto the positioning base 203 of the guide module 2. The positioning base 203 initially fixes the substrate with clips to prevent displacement during transport. Subsequently, the gear chain drive unit of the guide module 2 starts, driving the transmission platform 202 to move smoothly and linearly along the side rail 201 through tooth meshing transmission. At the same time, the lifting mechanism below the positioning base 203 adjusts the distance between the positioning base 203 and the transmission platform 202 according to preset process parameters, so that the height of the substrate matches the operation requirements of the soldering module 3, ensuring that the substrate can accurately reach the lower mold 301 of the soldering module 3.

[0057] Then, the infrared positioning module 305 of the soldering module 3 monitors the relative position of the substrate and the positioning hole 304 array in the lower mold 301 in real time. When the substrate reaches the designated soldering position, the system triggers a positioning signal, the toothed chain drive unit stops operating, and the substrate is accurately positioned. At this time, the drive motor 502 of the solder ball processing component 5 starts, and drives the housing 501 to slide back and forth along the rectangular groove 303 of the lower mold 301 through the lead screw 503 transmission mechanism. The double-sided brush fibers 505 at the bottom of the housing 501 first evenly sweep the solder balls in the rectangular groove 303 towards the positioning hole 304 array, so that the solder balls fall along the positioning holes 304 and accurately adhere to and initially bond with the solder paste pre-coated on the substrate surface; the conical scraper 506 in the middle applies uniform pressure to the solder balls to ensure that the solder balls and solder paste are tightly bonded, while pushing excess solder balls to both sides.

[0058] Subsequently, the solder balls in the temporary storage cavity 507 inside the housing 501 are replenished to the empty positioning hole 304 in real time through the inclined guide structure and the replenishment channel 508. Meanwhile, under the action of the negative pressure pump 5010, the negative pressure channel 509 adsorbs the excess solder balls and solder paste debris cleaned by the scraper 506, and flows back to the temporary storage cavity 507 through the negative pressure channel 509 and the output pipe 5011, realizing the recycling and reuse of solder balls.

[0059] After the tin plating is completed, the toothed chain drive unit starts again, transporting the substrate along the side rail 201 to the bottom of the mold hot pressing module 4. The lifting mechanism adjusts the height of the positioning base 203 again, so that the substrate and the hot pressing point 405 of the hot pressing mold 404 are precisely aligned.

[0060] Next, the heating module of the hot pressing module 4 is activated to preheat the hot pressing plate 403. The heat is evenly transferred to the hot pressing mold 404 through the hot pressing plate 403, raising the temperature of the hot pressing mold 404 to the preset melting temperature of the solder balls at 180-220℃. After the temperature stabilizes, the hydraulic rod 402 drives the hot pressing plate 403 to move downward. The hot pressing points 405 at the bottom of the hot pressing mold 404 contact the solder balls on the substrate one by one. The semi-circular positioning grooves 406 at the ends of the hot pressing points 405 wrap around the solder balls, preventing them from shifting during melting and guiding them to melt evenly.

[0061] Simultaneously, the hemispherical bottom of the hot-pressing point 405 works in conjunction with the positioning groove 406 to form a uniform hemispherical structure after the solder ball melts, realizing the transformation of the contact between the solder ball and the substrate from point contact to surface contact, significantly improving the welding area and conductivity stability. After the hot-pressing welding continues for a preset time, the hydraulic rod 402 drives the hot-pressing plate 403 to reset, the heating module stops working, and the hot-pressing mold 404 cools down naturally.

[0062] Subsequently, using a nitrogen reflow soldering process, the MLo is soldered onto the substrate PCB at a specific temperature. Finally, the toothed chain drive unit of guide module 2 is activated again to transport the soldered substrate to the equipment's discharge end, where the operator removes the substrate.

[0063] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A welding apparatus for MLO packaged devices, characterized in that, The device includes a guide module (2), a soldering module (3), and a mold hot pressing module (4). The guide module (2) is used to transport the substrate and guide the substrate through the soldering module (3) and the mold hot pressing module (4) in sequence. The soldering module (3) includes a lower mold (301) disposed directly above the guide module (2), an array of positioning holes (304), an infrared positioning module (305), and a solder ball processing component (5). The solder ball processing component (5) is slidably connected inside the lower mold (301). The mold hot pressing module (4) is located directly above the soldering module (3) and includes a hot pressing mold (404). The bottom of the hot pressing mold (404) is provided with hot pressing points (405) that correspond one-to-one with the array of positioning holes (304).

2. The welding apparatus according to claim 1, characterized in that, The guide module (2) includes a side rail (201), a toothed chain drive unit and a transmission platform (202). The toothed chain drive unit drives the transmission platform (202) to move linearly along the side rail (201) through tooth meshing transmission. The transmission platform (202) is provided with a positioning base (203) for supporting the substrate.

3. The welding apparatus according to claim 2, characterized in that, A lifting mechanism is provided below the positioning base (203). The lifting mechanism is used to adjust the distance between the positioning base (203) and the transmission platform (202). The output end of the lifting mechanism is fixedly connected to the positioning base (203).

4. The welding apparatus according to claim 1, characterized in that, The solder ball processing assembly (5) includes a housing (501), a drive motor (502), and a lead screw (503) transmission mechanism. The drive motor (502) is fixed on one side of the lower mold (301). The lead screw (503) transmission mechanism includes a lead screw (503) connected to the output end of the drive motor (502) and a threaded sleeve (504) fixed on the housing (501). The lead screw (503) and the threaded sleeve (504) form a helical transmission pair.

5. The welding apparatus according to claim 4, characterized in that, The bottom of the housing (501) is provided with brush fibers (505) and scraper (506). The brush fibers (505) are distributed on the bottom edge of the housing (501) to form a double-sided covering structure. The scraper (506) is located between the two rows of brush fibers (505) and has a conical bottom structure that contacts the surface of the lower mold (301).

6. The welding apparatus according to claim 5, characterized in that, The bristle fibers (505) are bonded to a removable mounting strip, which is fixed to the bottom of the housing (501) by a snap or bolt.

7. The welding apparatus according to claim 5, characterized in that, The housing (501) is provided with a temporary storage cavity (507) and a replenishment channel (508). The temporary storage cavity (507) is connected to the replenishment channel (508) through a sloping guide structure. The outlet of the replenishment channel (508) is located between the scraper (506) and the brush fibers (505) and corresponds one-to-one with the array of positioning holes (304).

8. The welding apparatus according to claim 7, characterized in that, The housing (501) is also provided with a negative pressure channel (509). The inlet of the negative pressure channel (509) is located between the scraper (506) and the brush fiber (505). The outlet of the negative pressure channel (509) is connected to the input end of the negative pressure pump (5010). The output end of the negative pressure pump (5010) is connected to the temporary storage chamber (507).

9. The welding apparatus according to claim 8, characterized in that, The negative pressure channel (509) and the supplementary channel (508) are arranged in a staggered manner at the bottom of the housing (501), and the distance between the inlet of the negative pressure channel (509) and the outlet of the supplementary channel (508) is 3-5mm.

10. The welding apparatus according to claim 1, characterized in that, The hot pressing point (405) at the bottom of the hot pressing mold (404) is integrally formed and a semi-circular positioning groove (406) is provided at the end. The opening direction of the positioning groove (406) faces the substrate, and the bottom of the hot pressing point (405) has a hemispherical structure.

Images