LED chip packaging production line and production process thereof

Abstract

The present invention relates to the field of chip packaging technology, and in particular to an LED chip packaging production line and its production process, including a double-track conveyor line for conveying substrates carrying LED chips, wherein the double-track conveyor line is sequentially provided with a loading device for sequentially arranging and conveying single substrates to the double-track conveyor line along its conveying direction, a crystal fixing device for dotting silver glue at a specific position of the substrate and installing the crystal at the glue dot position of the substrate, a heating device for reflow heating and curing the solder paste, and a sealing device for protecting the LED chip by filling glue. The present invention solves common problems such as silver glue aging, chip offset, flow soldering cold soldering, colloid cracking, and colloid residue in traditional packaging, and solves the problems of cold soldering and insufficient soldering in the traditional LED packaging process, thereby greatly improving the packaging quality and production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of chip packaging, and in particular to an LED chip packaging production line and a production process thereof. Background Art

[0002] LED (Light Emitting Diode) has become the representative of the new generation of light sources with its high efficiency, long life and environmental protection. In the LED packaging process, how to ensure the precise combination of chip and substrate, the stability of circuit and the protective performance of colloid are important indicators to measure the packaging quality. However, in actual production, it is often affected by many factors, resulting in low yield rate and rising defective rate, which seriously affects the economic benefits and brand image of the enterprise.

[0003] The LED chip packaging production line in the prior art has problems of silver glue aging and chip offset during the LED chip solidification process. At the same time, during the reflow soldering process, it is easy to have problems such as cold soldering and insufficient soldering due to improper operation of technicians. In addition, the temperature curve of the existing reflow soldering process heats up too quickly, which easily leads to the problem of colloid cracking. Summary of the invention

[0004] In order to solve the technical defects raised in the above-mentioned background technology, the purpose of the present invention is to provide an LED chip packaging production line and its production process to solve the common problems of silver glue aging, chip offset, flow soldering, colloid cracking and colloid residue in traditional packaging, so as to achieve high quality and high efficiency of LED packaging.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] An LED chip packaging production line includes a double-track conveyor line for conveying substrates carrying LED chips, wherein the double-track conveyor line is sequentially provided with a loading device for sequentially conveying single substrates to the double-track conveyor line along its conveying direction, a crystal fixing device for dotting silver glue at a specific position of the substrate and mounting a crystal at the dotting position of the substrate, a heating device for reflow heating and curing the solder paste, and a sealing device for performing glue filling and protection on the LED chip, wherein the crystal fixing device includes a workbench, a glue dispensing mechanism arranged on the workbench for coating the substrate with silver glue, and a dispensing mechanism located on one side of the glue dispensing mechanism for conveying and assembling a wafer at the glue dispensing position. A crystal retrieval mechanism is provided at the position of the dual-track conveyor line corresponding to the crystal retrieval mechanism, a displacement component for conveying the substrate and driving the substrate to move at the glue dispensing mechanism is arranged between the glue dispensing mechanism and the crystal retrieval mechanism, and the glue dispensing mechanism is slidably connected to the displacement component; a limiting component for preventing the substrate from shifting during crystal fixing is arranged at the position of the dual-track conveyor line corresponding to the crystal retrieval mechanism, the limiting component is located at the bottom end of the dual-track conveyor line, and one end of the limiting component extends to the surface of the dual-track conveyor line; by coating the outer surface of the substrate with silver glue under the action of the glue dispensing mechanism, and fixing the substrate coated with silver glue by the limiting component, the crystal retrieval mechanism can encapsulate the chip at the glue dispensing position corresponding to the substrate.

[0007] Preferably, the dispensing mechanism includes a dispensing frame, a dispensing gun for coating silver glue on the substrate, and a scraper plate for scraping off excess silver glue on the surface of the substrate. One side of the dispensing frame is movably connected to the longitudinal movable slide rail, and the other side is fixedly connected to the dispensing gun; there are multiple dispensing guns, and the multiple dispensing guns are arranged side by side on the dispensing frame, and one side of each dispensing gun is connected to a control valve; the scraper plate is arranged on the dispensing frame, and the scraper plate is arranged at the same height as the nozzle of the dispensing gun.

[0008] Preferably, the crystal retrieval mechanism includes a wafer table located between the double-track conveyor lines for holding crystals, a movable guide rail frame spanning the bidirectional conveyor lines, a vacuum suction cup slidably connected to the movable guide rail frame for sucking up the wafers and transferring them to the wafer table, and a packaging plug for packaging the wafers on the substrate. A plurality of suction cups for carrying the wafers are arranged in a circular array on the wafer table, and a plurality of accommodating cavities for adapting and installing the wafers are provided on the suction cups. The movable guide rail frame is fixed on the workbench, and a lifting drive assembly is slidably connected between the movable guide rail frame and the vacuum suction cup and the packaging plug, respectively.

[0009] Preferably, the vacuum suction cup and the packaging plug are arranged corresponding to the position of the accommodating cavity on the suction cup, and one end of the vacuum suction cup is connected to a material picking rod; one end of the packaging plug is connected to a transmission shaft, and the material picking rod and the transmission shaft are respectively fixed on the lifting drive assembly.

[0010] Preferably, the limiting assembly comprises a clamping claw, an articulated frame and a clamping cylinder, the output end of the clamping cylinder is transmission-connected to the articulated frame, and the bottom end of the clamping claw is hingedly connected to the articulated frame.

[0011] Preferably, the heating device includes a heating box, a hot air blower installed on the heating box, and a cooling fan. The box body of the heating box is a double-layer hollow structure, and a plurality of heating holes are evenly opened on the inner wall and the bottom end of the heating box; the hot air blower is arranged in the hollow side wall of the heating box, and the cooling fan is arranged on the top of the heating box.

[0012] Preferably, the glue sealing device includes a machine platform, a multi-axis movable bracket arranged on the machine platform, and a glue pouring assembly, wherein the multi-axis movable bracket is fixed on the machine platform; the glue pouring assembly consists of a glue storage tank and a glue pouring nozzle, and the glue storage tank and the glue pouring nozzle are slidably connected to the multi-glue spraying axis movable bracket, and the glue storage tank is communicated with the glue pouring nozzle.

[0013] Preferably, the loading device includes a tray for carrying the substrate, a storage rack for stacking and storing the trays, a loading drive mechanism arranged in the storage rack for driving the trays to circulate up and down, and a picking mechanism arranged at the top of the storage rack for grabbing the trays. One side of the storage rack is in contact with the double-track conveyor line, and the loading drive mechanism is arranged on both sides of the storage rack.

[0014] Preferably, the material picking mechanism includes a material picking slide frame and a material picking suction cup, the material picking slide frame is slidably connected to the material storage rack, and the material picking slide frame is arranged in front of the double-track conveyor line; the material picking suction cup is slidably connected along the length direction of the material picking slide frame.

[0015] A LED chip packaging production process, the production process comprising the following steps:

[0016] S1. Prepare materials: prepare the silver glue required for dispensing and bonding, place the silver glue stored below 0°C at room temperature, and let it stand for 3-5 hours before thawing;

[0017] S2, loading: the substrates are sequentially fed to the die-bonding station by the loading device;

[0018] S3, glue dispensing: silver glue is dispensed into the foot cup of the substrate by the glue dispensing mechanism, the height of the silver glue dispensing is 1 / 4 of the thickness of the wafer, and the wafer is fixed in the center of the foot cup of the substrate, and the offset is less than 1 / 4 of the wafer width;

[0019] S4, crystal bonding: the single wafer is peeled off by the crystal taking mechanism and then accurately placed on the glue dispensing position of the substrate;

[0020] S5, curing: put the substrate with the installed chip into the heating box, and heat the temperature in the heating box to 150℃±10℃-250℃±10℃. The solder paste used to solder other components will be melted by high temperature, and then the silver glue will be cured after keeping the temperature for 6-8 minutes to combine the crystal with the pad on the substrate, and finally it will be cooled quickly until the solder joint solidifies;

[0021] S6, glue sealing: The glue sealing device inserts a needle into the ear hole of the wafer to fill the glue until a small amount of glue overflows from the opposite hole; then the entire substrate is inverted and leveled, pressed firmly, and the excess glue part is wiped clean with a cotton swab; after the glue is filled, it is placed at room temperature, and the substrate is horizontally inverted and neatly stored in a stainless steel tray for 24 hours;

[0022] S7. Performance test: Use a unidirectional power supply test device to test the packaged LED, and observe its appearance for bubbles, debris, and yellowing of the copper column after the test.

[0023] In summary, the beneficial effects of the present invention are:

[0024] The present invention provides a double-track conveyor line, a feeding device, a crystal fixing device, a heating device and a sealing device, so that the LED chip packaging can automatically work together. At the same time, the fully automated crystal fixing device is used to accurately control the process of chip cutting and installation on the substrate, thereby avoiding the problems of silver glue aging and chip offset; the production efficiency of LED chip packaging is effectively improved; in addition, by optimizing the temperature control curve in the reflow soldering process, the problem of colloid cracking caused by cold soldering and insufficient soldering during reflow soldering in the traditional LED chip packaging process is solved, thereby greatly improving the packaging quality and production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the LED chip packaging production line of the present invention;

[0026] Figure 2 It is a structural schematic diagram of the feeding device in the present invention;

[0027] Figure 3 It is a structural schematic diagram of the glue dispensing mechanism in the present invention;

[0028] Figure 4 yes Figure 3 A magnified view of the structure at a in the middle;

[0029] Figure 5 It is a structural schematic diagram of the crystal taking mechanism in the present invention;

[0030] Figure 6 It is a structural schematic diagram of the limit assembly in the present invention;

[0031] Figure 7It is a schematic diagram of the structure of the heating device in the present invention;

[0032] Figure 8 It is a structural schematic diagram of the glue sealing device in the present invention;

[0033] Fig. 9 It is a structural schematic diagram of the testing device in the present invention;

[0034] Fig.10 It is a work flow chart of the LED chip packaging production process of the present invention.

[0035] 1. Double-track conveyor line; 2. Loading device; 21. Tray; 22. Storage rack; 23. Loading drive mechanism; 231. Screw drive assembly; 232. Rack drive assembly; 233. Chuck assembly; 24. Retrieving mechanism; 241. Retrieving slide rail rack; 242. Retrieving suction cup; 3. Crystal bonding device; 31. Workbench; 32. Glue dispensing mechanism; 321. Glue dispensing rack; 322. Glue dispensing gun; 323. Control valve; 324. Glue scraper; 33. Retrieving mechanism; 331. Wafer table; 3311. Suction cup; 3312. Rotating shaft; 3313. Servo motor; 332. Moving guide rail rack; 333. Vacuum suction cup; 3331. Retrieving Rod; 334, packaging plug; 3341, transmission shaft; 335, lifting drive assembly; 34, displacement assembly; 341, linear slide; 342, lateral moving slide; 343, longitudinal moving slide; 4, limit assembly; 41, clamping claw; 42, articulated frame; 43, clamping cylinder; 5, heating device; 51, heating box; 511, heating hole; 52, hot air blower; 53, cooling fan; 6, sealing device; 61, machine; 62, multi-axis movable bracket; 63, glue filling assembly; 631, glue storage tank; 632, glue filling nozzle; 7, testing device; 71, testing machine; 72, resistance and voltage testing assembly; 73, tooling fixture. DETAILED DESCRIPTION

[0036] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0037] Those skilled in the art should understand that, in the disclosure of the present invention, the orientation or position relationship indicated by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0038] In addition, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the description of the present invention, if there are words such as "several", it means one or more, "more" means two or more, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there are descriptions of first, second, and third, they are only used to distinguish technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0040] The following is combined with Figure 1-10 , an embodiment of an LED chip packaging production line and its production process of the present invention is further described in detail.

[0041] An LED chip packaging production line, such as Figure 1 As shown, it includes a double-track conveyor line 1 for conveying substrates carrying LED chips. The double-track conveyor line 1 is provided with a crystal fixing device 3, a heating device 5 and a sealing device 6 in sequence along its conveying direction. The head end of the double-track conveyor line 1 is provided with a feeding device 2, which is used to sequentially sort and convey single substrates to the double-track conveyor line 1; the crystal fixing device 3 is used to dot silver glue at a specific position of the substrate and install the crystal at the glue dot position of the substrate, the heating device 5 is used to reflow heat and cure the solder paste, and the sealing device 6 is used to protect the LED chip with glue; the end of the double-track conveyor line 1 is connected with a testing device 7, which is used to perform comprehensive testing on the packaged products.

[0042] Specifically, the LED chip package of the present invention adopts a surface mount package (SMD), which has the advantages of small size, large scattering angle, good luminous uniformity, high reliability, etc., wherein the automated loading device 2 can accurately position the substrate to ensure that the material flows to the double-track conveyor line 1, and the double-track conveyor line 1 can greatly improve its transportation efficiency, thereby improving production efficiency; and the crystal bonding device 3 is used to accurately control the amount of glue dispensed to prevent excessive glue from affecting the installation of the chip; at the same time, the crystal bonding device 3 is used to ensure that the chip and the carrier are firmly combined to resist the aging of the silver glue and the chip deflection; finally, the heating device 5 is set to adaptively adjust the PID to maintain temperature balance and prevent the cracking of the colloid; the encapsulated chip is injected with high density glue using the sealing device 6 to isolate external erosion and prevent the LED chip from being damaged. After the package is completed, the LED chip also needs to be tested for comprehensive performance by the testing device 7 to ensure that each product meets high standards.

[0043] In this embodiment, if Figure 2 As shown, the loading device 2 includes a tray 21 for carrying a substrate, a storage rack 22 for stacking and storing the trays 21, a loading drive mechanism 23 arranged in the picking rack for driving the trays 21 to circulate up and down, and a picking mechanism 24 arranged at the top of the storage rack 22 for grabbing the trays 21. One side of the storage rack 22 is in contact with the double-track conveyor line 1, and the loading drive mechanism 23 is arranged on both sides of the storage rack 22.

[0044] Specifically, the material picking mechanism 24 includes a picking rail frame 241 and a picking suction cup 242. The picking rail frame 241 is slidably connected to the material storage rack 22, and the picking rail frame 241 is arranged in front of the double-track conveyor line 1. The picking suction cup 242 is slidably connected along the length direction of the picking rail frame 241. When grabbing a substrate, the picking rail frame 241 moves along the X-axis and Y-axis directions of the material storage rack 22, thereby controlling the picking suction cup 242 to accurately pick up the substrate on the tray 21 and transfer it to the double-track conveyor line 1, thereby facilitating the subsequent installation of the wafer.

[0045] In this embodiment, if Figures 3 to 6As shown, the crystal bonding device 3 includes a workbench 31, a glue dispensing mechanism 32 arranged on the workbench 31 for coating the substrate with silver glue, and a crystal taking mechanism 33 located on one side of the glue dispensing mechanism 32 for conveying and assembling the wafer at the glue dispensing location, a displacement component 34 for conveying the substrate and driving the substrate to move at the glue dispensing mechanism 32 is arranged between the glue dispensing mechanism 32 and the crystal taking mechanism 33, and the glue dispensing mechanism 32 is slidably connected to the displacement component 34; a limit component 4 for preventing the substrate from shifting during crystal bonding is arranged at the position of the double-track conveyor line 1 corresponding to the crystal taking mechanism 33, and the limit component 4 is located at the double-track conveyor line 1 The bottom end, and one end of the limiting component 4 extends to the surface of the double-track conveyor line 1; the limiting component 4 includes a clamping claw 41, an articulated frame 42 and a clamping cylinder 43, the output end of the clamping cylinder 43 is transmission-connected to the articulated frame 42, and the bottom end of the clamping claw 41 is hingedly connected to the articulated frame 42; by coating the outer surface of the substrate with silver glue under the action of the dispensing mechanism 32, and fixing the substrate coated with silver glue by the limiting component 4, so that the crystal retrieval mechanism 33 encapsulates the chip at the dispensing position corresponding to the substrate, thereby avoiding the problems of silver glue aging and chip offset, and effectively improving the production efficiency of LED chip packaging.

[0046] Specifically, the glue dispensing mechanism 32 includes a glue dispensing frame 321, a glue dispensing gun 322 for coating silver glue on the substrate, and a scraper plate 324 for scraping off excess silver glue on the surface of the substrate. One side of the glue dispensing frame 321 is movably connected to the longitudinal movable slide rail 343 hinge frame, and the other side is fixedly connected to the glue dispensing gun 322. There are multiple glue dispensing guns 322, and multiple glue dispensing guns 322 are arranged side by side on the glue dispensing frame 321. One side of each glue dispensing gun 322 is connected to a control valve 323; the glue scraper plate 324 is arranged on the glue dispensing frame 321, and the glue scraper plate 324 is arranged at the same height as the nozzle of the glue dispensing gun 322; the glue output of the glue dispensing gun 322 is accurately controlled by using the control valve 323 to ensure uniform coverage of the entire chip surface. The displacement assembly 34 includes a linear slide 341 arranged along the length direction of the double-track conveyor line 1, a transverse movable slide 342 slidably connected to the linear slide 341, and a longitudinal movable slide 343 connected to the transverse movable slide 342. The transverse movable slide 342 is arranged across the top of the double-track conveyor line 1; the longitudinal movable slide 343 is slidably connected to the transverse movable slide 342 and the dispensing mechanism 32 through guide sleeves.

[0047] In this embodiment, if Figure 3 , 4As shown, the crystal retrieval mechanism 33 includes a wafer table 331 located between the double-track conveyor line 1 for holding crystals, a movable guide frame 332 spanning the bidirectional conveyor line, a vacuum suction cup 333 slidably connected to the movable guide frame 332 for sucking the wafer and transferring it to the wafer table 331, and a packaging plug 334 for packaging the wafer on the substrate. A circular array of suction cups 3311 for carrying the wafer is provided on the wafer table 331, and a plurality of accommodating cavities for adapting and installing the wafer are provided on the suction cups 3311; the movable guide frame 332 is fixed on the workbench 31, and a lifting drive assembly 335 clamping cylinder is slidably connected between the movable guide frame 332 and the vacuum suction cup 333 and the packaging plug 334, respectively.

[0048] Specifically, the working principle of the die bonder is to firmly fix the chip on the substrate by fixing the packaging substrate, coating silver glue, dispensing the chip, and UV curing. In the process of dispensing and coating, the viscosity and fluidity of the glue need to be controlled. In the process of fixing the chip on the substrate, the top surface of the chip is first placed on the substrate with the top surface facing up. Since the bottom end of the wafer table 331 is connected to a rotating shaft 3312 for driving its rotation, and one end of the rotating shaft 3312 is connected to a servo motor 3313 through a coupling transmission, the wafer table 331 can drive the chip to rotate. Then, the vacuum suction cup 333 is used to remove the chips one by one and transfer them to the suction cup 3311 on the wafer table 331. The installation cavity opened on the suction cup 3311 is used to stabilize the chip. Finally, the qualified chip in the installation cavity is picked up by the packaging plug 334 and placed on the substrate for packaging. When grabbing the chip, the packaging plug 334 can use external air pressure to absorb and pick up the chip.

[0049] Among them, the vacuum suction cup 333 and the packaging plug 334 are arranged corresponding to the position of the accommodating cavity on the suction cup 3311, and one end of the vacuum suction cup 333 is connected to the material picking rod 3331; one end of the packaging plug 334 is connected to the transmission shaft 3341, and the material picking rod 3331 and the transmission shaft 3341 are respectively fixed on the lifting drive assembly 335. The lifting drive assembly 335 adopts the structure of the cylinder driven slide rail commonly used in the existing industry, so it is not described in detail. The vacuum suction cup 333 and the packaging plug 334 are driven by the lifting drive assembly 335 to move up, down, left and right along the movable guide frame 332, thereby improving the chip grabbing and assembly efficiency.

[0050] In this embodiment, if Figure 7 As shown, the heating device 5 includes a heating box 51, a hot air blower 52 installed on the heating box 51, and a cooling fan 53. The box body of the heating box 51 is a double-layer hollow structure, and a plurality of heating holes 511 are evenly opened on the inner wall and the bottom end of the heating box 51; the hot air blower 52 is arranged in the hollow side wall of the heating box 51, and the cooling fan 53 is arranged on the top of the heating box 51.

[0051] Specifically, apply a proper amount of solder paste in an appropriate form on the pads of the substrate in advance, and then place the chip and SMT components in the corresponding positions; since the solder paste has a certain viscosity, it can fix the components; then the substrate with the chip and the components mounted is conveyed through the double-track conveyor line 1 to enter the heating box 51, which is divided into a preheating zone, a heat preservation zone, a welding zone and a cooling zone. The set temperature in each zone is different. After the solder paste is preheated and dried, heated and melted, heat-insulated and wetted, and solidified in the cooling zone, the chip, components and the pads on the substrate are combined. Among them, the core link of reflow soldering is to use the hot air blower 52 to heat, melt the solder and flow and infiltrate again, completing the soldering process of the substrate.

[0052] In this embodiment, if Figure 8 As shown, the glue sealing device 6 includes a machine platform 61, a multi-axis movable bracket 62 and a glue pouring assembly 63 arranged on the machine platform 61, the multi-axis movable bracket 62 is fixed on the machine platform 61, the glue pouring assembly 63 consists of a glue storage tank 631 and a glue pouring nozzle 632, the glue storage tank 631 and the glue pouring nozzle 632 are slidably connected to the multi-axis movable bracket 62, and the glue storage tank 631 is communicated with the glue pouring nozzle 632.

[0053] Specifically, chip potting glue plays an important role in the field of electronic packaging with its advantages of high viscosity, excellent insulation performance, aging resistance, waterproofness and environmental protection, and provides a solid guarantee for the stable, safe and reliable operation of electronic products. This enables the potting glue to adapt to various complex working environments and ensure that electronic components can operate stably under various conditions. It can effectively prevent short circuits and leakage between electronic components, ensure the normal operation of electronic equipment, and improve the reliability and safety of products. In order to seal the packaged LED chip, the multi-axis movable bracket 62 is used to control the potting nozzle 632 to evenly fill the silver glue at the chip installation position until the silver glue covers the surface of the chip to form a protective layer.

[0054] In this embodiment, if Fig. 9 As shown, the test device 7 includes a test platform 71 and a resistance and voltage test component 72 disposed on the test platform 71. The test platform 71 is provided with a fixture 73 for clamping and fixing the LED. The resistance and voltage test component 72 has a dynamic power monitoring and short circuit protection mechanism.

[0055] Specifically, the principle of measuring the junction temperature of the LED using the resistance and voltage test assembly 72 is that the forward voltage drop of the LED under a specific current is linearly related to the temperature of the LED chip. Therefore, it is only necessary to test the forward voltage drop values ​​at two or more temperature points to determine the slope of the relationship between the LED voltage and temperature, that is, the voltage temperature coefficient K value, in units of mV / °C. By calculating the K value, the temperature (junction temperature) Tj of the chip can be calculated by measuring the real-time forward voltage drop value. In addition, the luminous flux of the LED needs to be tested. There are two methods for testing the luminous flux, namely the integrating sphere method and the variable angle photometer method.

[0056] A LED chip packaging production process, such as Fig.10 As shown, the production process includes the following steps:

[0057] S1. Prepare materials: prepare the silver glue required for dispensing and bonding, place the silver glue stored below 0°C at room temperature, and let it stand for 3-5 hours before thawing;

[0058] S2, loading: feeding the substrate to the die bonding station in an orderly manner through the loading device 2;

[0059] S3, glue dispensing: silver glue is dispensed into the foot cup of the substrate by the glue dispensing mechanism 32, the height of the silver glue dispensing is 1 / 4 of the thickness of the wafer, and the wafer is fixed in the center of the foot cup of the substrate, and the offset is less than 1 / 4 of the wafer width;

[0060] S4, crystal bonding: the single wafer is peeled off by the crystal taking mechanism 33 and then accurately placed on the glue dotted position of the substrate;

[0061] S5, curing: the substrate with the mounted wafer is sent into the heating box 51, and the temperature in the heating box 51 is raised to 150℃±10℃-250℃±10℃, the solder paste used for soldering other components is melted by the high temperature, and then the silver glue is cured after being kept warm for 1.5-2h, so that the wafer and other components are combined with the pads on the substrate, and finally the solder joint is quickly cooled until the solder joint solidifies;

[0062] S6, glue sealing: The glue sealing device 6 injects glue by inserting a needle into the ear hole of the wafer until a small amount of glue overflows from the opposite hole; then the entire substrate is inverted and leveled, pressed firmly, and the excess glue part is wiped clean with a cotton swab; after the glue is injected, it is placed at room temperature, and the substrate is horizontally inverted and neatly stored in a stainless steel tray for 24 hours;

[0063] S7, performance test: Use the test device 7 with a unidirectional power supply to test the packaged LED, and after the test, observe its appearance for bubbles, debris, and yellowing of the copper column.

[0064] Specifically, in step S5, when the LED is subjected to the reflow soldering process, the substrate carrying the wafer is transported to the heating box 51 for heating by using the double-track conveyor line 1, wherein as the temperature and time of the substrate change in the heating box 51, the solder paste on the surface thereof undergoes the following changes;

[0065] First, the area where the substrate begins to be heated to 150° C. in the heating box 51 is called the heating zone. The time of the heating zone is set at 60-90s, and the slope is controlled between 2-4 (the slope refers to the time for the substrate to pass through a certain area of ​​the reflow soldering divided by the absolute value of the temperature change in this time period); in this area, the temperature of the components on the substrate rises relatively quickly linearly, and the low-boiling point solvent in the solder paste begins to partially evaporate; if the slope is too large and the heating rate is too fast, the solder paste is bound to splash due to the rapid volatilization of the low-boiling point solvent or the rapid boiling of water vapor, thereby causing a "tin bead" defect after heating. Therefore, controlling the slope between 2-4 can effectively avoid this situation;

[0066] Then, the substrate starts to heat up until the temperature rises slowly from 150°C to 200°C. This area is called the insulation zone. The heating time is kept between 60-120s. At this time, each part of the substrate is slowly heated by the hot air blower 52. The temperature rises slowly over time, with a slope between 0.3-0.8. At this time, the organic solvent in the solder paste continues to evaporate. The active substances are activated by the temperature and begin to work, removing oxides from the pad surface, component feet, and tin powder alloy powder.

[0067] Next, the area where the substrate is quickly heated to above 230°C is called the reflow zone. The heating time is maintained at 30-70s. At this time, the temperature on the substrate rises to the liquidus line of the tin powder alloy at a relatively fast rate, and the solder begins to melt. It continues to rise linearly to 250°C and then maintains for a period of time before starting to drop to the solidus line. At this time, various components in the solder paste fully play their role: rosin or resin softens and forms a protective film around the solder to isolate it from oxygen; surfactants are activated to reduce the surface tension between the solder and the surface to be soldered, and enhance the wetting power of the liquid solder;

[0068] Finally, the section where the solder joint temperature decreases from the liquidus line is called the cooling zone. The temperature is rapidly reduced to 150-170°C by the cooling fan 53. At this time, the solder joint re-solidifies into a solid solder joint. The rapid cooling can form a smooth, uniform and thin intermetallic compound, forming fine tin-rich dendrites and fine grains dispersed in the tin matrix, which significantly enhances and improves the mechanical properties and reliability of the solder joint.

[0069] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. An LED chip packaging production line, comprising a double-track conveyor line for conveying substrates carrying LED chips, wherein the double-track conveyor line is provided with a loading device for sequentially conveying single substrates to the double-track conveyor line, a crystal fixing device for dotting silver glue at a specific position of the substrate and mounting the crystal at the glue dot position of the substrate, a heating device for reflow heating and curing the solder paste, and a sealing device for performing glue filling and protection on the LED chip, characterized in that: The crystal bonding device comprises a workbench, a glue dispensing mechanism arranged on the workbench for coating silver glue on the substrate, and a crystal retrieval mechanism located on one side of the glue dispensing mechanism for conveying and assembling the wafer at the glue dispensing position, a displacement assembly for conveying the substrate and driving the substrate to move at the glue dispensing mechanism is arranged between the glue dispensing mechanism and the crystal retrieval mechanism, and the glue dispensing mechanism is slidably connected to the displacement assembly; a limit assembly for preventing the substrate from being offset during crystal bonding is arranged at a position of the double-track conveyor line corresponding to the crystal retrieval mechanism, the limit assembly is located at the bottom end of the double-track conveyor line, and one end of the limit assembly extends to the surface of the double-track conveyor line; by coating the outer surface of the substrate with silver glue under the action of the glue dispensing mechanism, and fixing the substrate coated with silver glue by the limit assembly, the crystal retrieval mechanism can encapsulate the wafer at the glue dispensing position corresponding to the substrate; The dispensing mechanism includes a dispensing frame, a dispensing gun for coating silver glue on the substrate, and a scraper for scraping off excess silver glue on the surface of the substrate. One side of the dispensing frame is movably connected to the longitudinal movable slide rail, and the other side is fixedly connected to the dispensing gun. There are multiple dispensing guns, and the multiple dispensing guns are arranged side by side on the dispensing frame. One side of each dispensing gun is connected to a control valve. The scraper is arranged on the dispensing frame, and the scraper is arranged at the same height as the nozzle of the dispensing gun. The crystal retrieval mechanism includes a wafer table located between the double-track conveyor lines for holding crystals, a movable guide frame spanning the bidirectional conveyor lines, a vacuum suction cup slidably connected to the movable guide frame for sucking up the wafers and transferring them to the wafer table, and a packaging plug for packaging the wafers on the substrate. A plurality of suction cups for carrying the wafers are arranged in a circular array on the wafer table, and a plurality of accommodating cavities for adapting and installing the wafers are provided on the suction cups. The movable guide frame is fixed on the workbench, and a lifting drive assembly is slidably connected between the movable guide frame and the vacuum suction cup and the packaging plug, respectively.

2. The LED chip packaging production line according to claim 1, characterized in that: The vacuum suction cup and the packaging plug are arranged corresponding to the position of the accommodating cavity on the suction cup, and one end of the vacuum suction cup is connected to a material picking rod; one end of the packaging plug is connected to a transmission shaft, and the material picking rod and the transmission shaft are respectively fixed on the lifting drive assembly.

3. The LED chip packaging production line according to claim 1, characterized in that: The position limiting assembly comprises a clamping claw, an articulated frame and a clamping cylinder. The output end of the clamping cylinder is transmission-connected to the articulated frame, and the bottom end of the clamping claw is articulated to the articulated frame.

4. The LED chip packaging production line according to claim 1, characterized in that: The heating device includes a heating box, a hot air blower installed on the heating box, and a cooling fan. The box body of the heating box is a double-layer hollow structure, and a plurality of heating holes are evenly opened on the inner wall and the bottom end of the heating box; the hot air blower is arranged in the hollow side wall of the heating box, and the cooling fan is arranged on the top of the heating box.

5. The LED chip packaging production line according to claim 1, characterized in that: The glue sealing device includes a machine platform, a multi-axis movable bracket arranged on the machine platform, and a glue pouring assembly, wherein the multi-axis movable bracket is fixed on the machine platform; the glue pouring assembly consists of a glue storage tank and a glue pouring nozzle, wherein the glue storage tank and the glue pouring nozzle are slidably connected to the multi-glue spraying axis movable bracket, and the glue storage tank is communicated with the glue pouring nozzle.

6. The LED chip packaging production line according to claim 1, characterized in that: The loading device includes a tray for carrying substrates, a storage rack for stacking and storing trays, a loading drive mechanism arranged in the storage rack for driving the trays to circulate up and down, and a picking mechanism arranged at the top of the storage rack for grabbing the trays. One side of the storage rack is in contact with the double-track conveyor line, and the loading drive mechanism is arranged on both sides of the storage rack.

7. The LED chip packaging production line according to claim 6, characterized in that: The material picking mechanism comprises a material picking slide rail frame and a material picking suction cup. The material picking slide rail frame is slidably connected to the material storage rack, and the material picking slide rail frame is arranged in front of the double-track conveyor line; the material picking suction cup is slidably connected along the length direction of the material picking slide rail frame.

8. A LED chip packaging production process, comprising the application of the LED chip packaging production line according to any one of claims 1 to 7, characterized in that: The production process includes the following steps: S1. Prepare materials: prepare the silver glue required for dispensing and bonding, place the silver glue stored below 0°C at room temperature, and let it stand for 3-5 hours before thawing; S2, loading: the substrate is fed to the die bonding station in an orderly manner through the loading device; S3, glue dispensing: silver glue is dispensed into the foot cup of the substrate by the glue dispensing mechanism, the height of the silver glue dispensing is 1 / 4 of the thickness of the wafer, and the wafer is fixed in the center of the foot cup of the substrate, and the offset is less than 1 / 4 of the wafer width; S4, crystal bonding: the single wafer is peeled off by the crystal taking mechanism and then accurately placed on the glue dispensing position of the substrate; S5, curing: put the substrate with the installed chip into the heating box, and heat the temperature in the heating box to 150℃±10℃-250℃±10℃. The solder paste used to solder other components will be melted by high temperature, and then the silver glue will be cured after keeping the temperature for 6-8 minutes to combine the crystal with the pad on the substrate, and finally it will be cooled quickly until the solder joint solidifies; S6, glue sealing: The glue sealing device inserts a needle into the ear hole of the wafer to fill the glue until a small amount of glue overflows from the opposite hole; then the entire substrate is inverted and leveled, pressed firmly, and the excess glue part is wiped clean with a cotton swab; after the glue is filled, it is placed at room temperature, and the substrate is horizontally inverted and neatly stored in a stainless steel tray for 24 hours; S7. Performance test: Use a unidirectional power supply test device to test the packaged LED, and observe its appearance for bubbles, debris, and yellowing of the copper column after the test.

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