Packaging method of LED light-emitting panel
By using transfer substrate and bearing substrate in the LED packaging process, combining optical image measurement and reflow soldering process, and applying uniform pressure using the bearing film, the problems of low chip transfer efficiency and complex process in traditional processes are solved, and high precision is achieved. High efficiency LED package.
Patent Information
- Application Number
- CN202311045099.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-18
- Publication Date
- 2024-12-13
AI Technical Summary
The traditional LED packaging process is affected by the accuracy and speed of mechanical transfer equipment during the chip transfer process, resulting in low chip transfer efficiency, and complex processes leading to high production efficiency and cost. The market urgently needs packaging technology with high accuracy, fast speed and simple processes.
The transfer substrate and the bearing substrate are used for LED chip transfer, the pad position is detected through optical image measurement equipment, and the uniform pressure is applied using the bearing film as the buffer layer. Combined with the reflow soldering process, high-precision and efficient chip connection are achieved, simplifying the process flow.
It realizes high yield, high efficiency and high precision for LED chip transfer, reduces production costs, simplifies process flow, and improves production efficiency.
Smart Images
Figure CN119133324A_ABST
Abstract
Description
Technical Field
[0001] The invention provides a packaging method for an LED light-emitting panel, belonging to the technical field of LED packaging technology. Background Art
[0002] LED packaging is a very important part of the LED manufacturing process. LED packaging can provide sufficient protection for the chip to prevent the chip from being exposed to the air or causing mechanical damage, allowing the LED to have better luminous efficiency and heat dissipation environment, thereby increasing the life of the LED.
[0003] In practical applications, due to the reduction in the size of LED chips, higher requirements are placed on packaging accuracy and speed. In the process of transferring chips to substrates, the traditional process is affected by the accuracy and speed of mechanical transfer equipment, resulting in low chip transfer efficiency. In addition, the chips will tilt and shift during the transfer process, resulting in low chip transfer yield. At the same time, due to the complex process, the traditional process has low efficiency in practical applications, and the processing cost and processing time remain high. Therefore, the market is in urgent need of an LED packaging technology with high accuracy, fast speed and simple process. Summary of the invention
[0004] In view of the shortcomings of the prior art, the present invention proposes a packaging method for an LED light emitting panel, which aims to solve the problem of low yield of LED chips due to uneven force during the packaging process.
[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a packaging method of an LED light-emitting panel, using a transfer substrate and a carrier substrate to transfer LED chips, wherein the transfer substrate is composed of a bottom plate and a receiving film from bottom to top, and a pad corresponding to the LED chip array is provided on the carrier substrate, and the method comprises the following steps: S1: Use an optical image measuring device to detect the relative position of the pads on the carrier substrate. According to the detection results, the LED chip is transferred to the corresponding position of the receiving film on the transfer substrate through a transfer device, and the solder paste is printed on the pads of the carrier substrate through a printing device; S2: Flip the transfer substrate with the LED chip attached, adjust the distance and relative position between the transfer substrate and the carrier substrate, make the receiving film on the transfer substrate attached to the carrier substrate, make the LED chip and the pad position of the carrier substrate correspond, make the LED chip contact with the solder paste on the pad of the carrier substrate, apply a certain pressure to the receiving film, make the receiving film produce elastic deformation, and attach to the carrier substrate; S3: soldering the LED chip to the pad of the carrier substrate using a reflow soldering process to complete the electrical connection between the LED chip and the carrier substrate; S4: removing the bottom plate of the transfer substrate and performing high temperature curing on the receiving adhesive film.
[0006] In step S1, the transfer device uses a chip sorter, and the optical image measurement equipment uses an AOI automatic optical inspection instrument. The chip sorter rearranges the LED chips according to the AOI optical inspection data and transfers them to the receiving film, so that the arrangement of the LED chips on the receiving film is consistent with the arrangement of the pads on the carrier substrate.
[0007] Positioning points are set on the carrier substrate and the transfer substrate. The chip sorter performs precise alignment based on the AOI positioning point optical detection data, providing a reference for the subsequent alignment of the LED chip and the pad.
[0008] The receiving adhesive film is a transparent elastic adhesive film, and the receiving adhesive film is attached to the bottom plate.
[0009] The thickness of the receiving adhesive film is 200-500um.
[0010] The bottom plate is made of transparent glass material.
[0011] The carrier substrate is specifically a PCB board, a glass substrate or a ceramic substrate.
[0012] The solder paste is LED solid crystal solder paste.
[0013] The reflow soldering process adopts a laser reflow soldering process or an infrared reflow soldering process.
[0014] The beneficial effects of the present invention compared with the prior art are as follows: 1. Compared with conventional processes, the present invention applies uniform pressure to the chip by using a receiving adhesive film as a buffer layer during the LED chip transfer process, thereby avoiding chip position displacement, tilting or even damage caused by uneven force on the LED chip, and achieving high yield, high efficiency and high precision in LED chip transfer.
[0015] 2. Compared with the traditional COB packaging process, the present invention simplifies the process flow, reduces production costs and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention will be further described below in conjunction with the accompanying drawings: Figure 1 A schematic diagram of the structure of attaching the LED chip on the epitaxial wafer to the transfer substrate receiving film; Figure 2 A schematic diagram of the three-dimensional structure of attaching the LED chip on the epitaxial wafer to the transfer substrate receiving film; Figure 3 A schematic diagram of the process of printing solder paste onto a carrier substrate through a steel screen; Figure 4 A three-dimensional schematic diagram of printing solder paste onto a carrier substrate through a steel screen; Figure 5 It is a schematic diagram of the structure in which the transfer substrate with LED chips attached is turned over and contacts with the carrier substrate; Figure 6 Schematic diagram of the process of applying uniform pressure to the transfer substrate so that the receiving film and the chip are attached to the carrier substrate; Figure 7 A schematic diagram of the process of soldering a chip onto a carrier substrate using a reflow soldering process; Figure 8 A schematic diagram of the process of separating the bottom plate of the transfer substrate from the receiving adhesive film; In the figure: 1 is an LED chip, 2 is a transfer substrate, 201 is a receiving film, 202 is a bottom plate, 301 is a scraper, 302 is solder paste, 303 is a steel mesh, and 4 is a carrier substrate. DETAILED DESCRIPTION
[0017] like Figures 1 to 8 As shown, the present invention provides a packaging method for an LED light-emitting panel, using a transfer substrate 2 and a carrier substrate 4 to transfer an LED chip 1, wherein the transfer substrate 2 is composed of a bottom plate 202 and a receiving adhesive film 201 from bottom to top, and the carrier substrate 4 is provided with pads corresponding to the LED chip array, and the method comprises the following steps: S1: using an optical image measuring device to detect the relative position of the pads on the carrier substrate 4, and according to the detection result, transferring the LED chip 1 to the corresponding position of the receiving film 201 on the transfer substrate 2 by a transfer device, and printing the solder paste on the pads of the carrier substrate 4 by a printing device; S2: Turn over the transfer substrate 2 with the LED chip 1 attached, adjust the distance and relative position between the transfer substrate 2 and the carrier substrate 4, so that the receiving adhesive film 201 on the transfer substrate 2 is attached to the carrier substrate 4, the pad positions of the LED chip 1 and the carrier substrate 4 correspond, so that the LED chip 1 contacts the solder paste on the pad of the carrier substrate 4, and a certain pressure is applied to the receiving adhesive film 201, so that the receiving adhesive film 201 produces elastic deformation and is attached to the carrier substrate 4; S3: soldering the LED chip 1 to the solder pad of the carrier substrate 4 using a reflow soldering process to complete the electrical connection between the LED chip 1 and the carrier substrate 4; S4: removing the bottom plate 201 of the transfer substrate 2 and curing the receiving adhesive film 202 at high temperature.
[0018] In step S1, the transfer device uses a chip sorter, and the optical image measurement equipment uses an AOI automatic optical inspection instrument. The chip sorter rearranges the LED chips 1 according to the AOI optical inspection data and transfers them to the receiving film 201, so that the arrangement of the LED chips 1 on the receiving film 201 is consistent with the arrangement of the pads on the supporting substrate 4.
[0019] Positioning points are set on the carrier substrate 4 and the transfer substrate 2, and the chip sorter performs precise alignment according to the AOI positioning point optical detection data, providing a reference for the subsequent alignment of the LED chip 1 and the pad.
[0020] The receiving adhesive film 201 is a transparent elastic adhesive film, and the receiving adhesive film is attached to the bottom plate.
[0021] The receiving adhesive film 201 has a thickness of 200-500 um.
[0022] The bottom plate 202 is made of transparent glass material.
[0023] The carrier substrate 4 is specifically a PCB board, a glass substrate or a ceramic substrate.
[0024] The solder paste is LED solid crystal solder paste.
[0025] The reflow soldering process adopts a laser reflow soldering process or an infrared reflow soldering process.
[0026] The method of the present invention is further described below with reference to the accompanying drawings. The method of the present invention is implemented in the following steps: Step 1, such as Figure 1 , 2 As shown, the transfer substrate 2 is composed of a bottom plate 202 and a receiving film 201 from bottom to top. The receiving film 201 is a transparent elastic film, such as silica gel, which can be attached or adsorbed on the bottom plate 202, and the LED chip 1 is adsorbed on the receiving film 201 by van der Waals force or electrostatic force; the relative position of the pads of the carrier substrate 4 is detected by an AOI automatic optical detector, and stored and memorized. According to the detection result, the LED chip 1 is then transferred to the receiving film 201 on the transfer substrate 2 by a transfer device, i.e., a chip sorter, to achieve the rearrangement of the LED chip 1 corresponding to the pad position on the carrier substrate 4. Alternatively, according to the storage and memory of the position of the positioning point of the carrier substrate 4 on the AOI automatic optical detector, a reference point can be marked on the receiving film 201 by laser or marking, and the LED chip 1 can be accurately aligned with the pad on the carrier substrate 4 according to the reference point.
[0027] Step 2, such as Figure 3 , 4 As shown, the small holes of the steel mesh 303 are aligned with the pads of the carrier substrate 4 , and the solder paste 302 is printed on the pads of the carrier substrate 4 through the steel mesh 303 using a scraper 301 .
[0028] Step 3, such as Figure 5As shown, flip the transfer substrate 2, adjust the height and horizontal position of the transfer substrate 2, and align the LED chip 1 attached to the receiving film 201 with the pad position of the carrier substrate 4 after printing the solder paste 302, so that the pins of the LED chip 1 are in contact with the solder paste 302 on the pad of the carrier substrate 4.
[0029] Step 4, such as Figure 6 As shown, uniform pressure is applied to the transfer substrate 2 to cause the receiving adhesive film 201 to produce elastic deformation, and the LED chip 1 is attached to the carrier substrate 4, and the receiving adhesive film 201 is attached to the surface of the carrier substrate 4. The applied pressure does not exceed the elastic limit of the receiving adhesive film 201, and the LED chip 1 is not damaged.
[0030] Step 5, such as Figure 7 As shown, by laser irradiating the transfer substrate 2, the solder paste 302 is melted, and the LED chip 1 is soldered to the pad of the carrier substrate 4, completing the electrical connection between the LED chip 1 and the carrier substrate 4. The bottom plate 202 of the transfer substrate 2 is a transparent glass material, and the reflow soldering can also use infrared soldering.
[0031] Step 6, such as Figure 8 As shown, the bottom plate 202 is moved to separate the bottom plate 202 from the receiving film 201 that has been adhered to the surface of the carrier substrate 4, and the receiving film 201 is cured at a high temperature within a temperature range of 90±5° C. The method for removing the bottom plate 202 is to open a gap between the receiving film 201 and the bottom plate 202, inject liquid, and then slowly remove the bottom plate 202.
[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A packaging method for an LED light-emitting panel, characterized in that: The LED chip is transferred by using a transfer substrate and a carrier substrate, wherein the transfer substrate is composed of a bottom plate and a receiving film from bottom to top, and a pad corresponding to the LED chip array is arranged on the carrier substrate. The method comprises the following steps: S1: Use an optical image measuring device to detect the relative position of the pads on the carrier substrate. According to the detection results, the LED chip is transferred to the corresponding position of the receiving film on the transfer substrate through a transfer device, and the solder paste is printed on the pads of the carrier substrate through a printing device; S2: Flip the transfer substrate with the LED chip attached, adjust the distance and relative position between the transfer substrate and the carrier substrate, make the receiving film on the transfer substrate attached to the carrier substrate, make the LED chip and the pad position of the carrier substrate correspond, make the LED chip contact with the solder paste on the pad of the carrier substrate, apply a certain pressure to the receiving film, make the receiving film produce elastic deformation, and attach to the carrier substrate; S3: soldering the LED chip to the pad of the carrier substrate using a reflow soldering process to complete the electrical connection between the LED chip and the carrier substrate; S4: removing the bottom plate of the transfer substrate and performing high temperature curing on the receiving adhesive film.
2. The packaging method of an LED light emitting panel according to claim 1, characterized in that: In step S1, the transfer device uses a chip sorter, and the optical image measurement equipment uses an AOI automatic optical inspection instrument. The chip sorter rearranges the LED chips according to the AOI optical inspection data and transfers them to the receiving film, so that the arrangement of the LED chips on the receiving film is consistent with the arrangement of the pads on the carrier substrate.
3. The packaging method of an LED light emitting panel according to claim 2, characterized in that: Positioning points are set on the carrier substrate and the transfer substrate. The chip sorter performs precise alignment based on the AOI positioning point optical detection data, providing a reference for the subsequent alignment of the LED chip and the pad.
4. A packaging method for an LED light emitting panel according to any one of claims 1 to 3, characterized in that: The receiving adhesive film is a transparent elastic adhesive film, and the receiving adhesive film is attached to the bottom plate.
5. The packaging method of an LED light emitting panel according to claim 4, characterized in that: The thickness of the receiving adhesive film is 200-500um.
6. A packaging method for an LED light emitting panel according to any one of claims 1 to 3, characterized in that: The bottom plate is made of transparent glass material.
7. A packaging method for an LED light emitting panel according to any one of claims 1 to 3, characterized in that: The carrier substrate is specifically a PCB board, a glass substrate or a ceramic substrate.
8. A packaging method for an LED light emitting panel according to any one of claims 1 to 3, characterized in that: The solder paste is LED solid crystal solder paste.
9. A packaging method for an LED light emitting panel according to any one of claims 1 to 3, characterized in that: The reflow soldering process adopts a laser reflow soldering process or an infrared reflow soldering process.