A method and system for evaluating the resistance of die-bonding adhesive to rotation of a chip

Abstract

The application belongs to the technical field of LED packaging, and particularly relates to a method and system for evaluating the anti-chip displacement and rotation of die bonding glue. The method comprises the following steps: selecting a conventional LED support, wherein a functional area of the LED support can accommodate at least two chips; setting at least two chips in the functional area through a die bonder, and debugging the interval distance between adjacent chips to a preset interval distance; respectively applying die bonding glue to the bottom of each chip through a dispensing process, so that the die bonding glue covers the four edges of the bottom of the chip; after a preset reaction time, observing whether the chip is displaced or rotated; the application saves the use of special COB supports, greatly reduces the test cost, and can conveniently simulate the actual use environment of dense chips. The operation is simple, the evaluation is rapid, and the result is intuitive and reliable.

Description

Technical Field

[0001] This application belongs to the field of LED packaging technology, specifically relating to a method and system for evaluating the resistance of die-bonding adhesive to chip displacement and rotation. Background Technology

[0002] In the field of LED packaging, the die bonding process uses adhesive to bond the chip to a designated area of ​​the substrate to form an electrical / thermal path. However, in current COB dense packaging, when the chip spacing is reduced to 100-150μm, excessive die bonding adhesive can easily cause the adhesive of adjacent chips to merge and flow, resulting in chip displacement and wire bonding failure. Existing evaluation methods rely on the dense arrangement of chips on actual COB substrates, which results in serious chip waste, high testing costs, and limited applicability, because only a few packaging plants have the conditions for COB operations. There is an urgent need to develop a fast, low-cost, and universal testing method that can accurately characterize the resistance of die bonding adhesive to displacement and rotation. Summary of the Invention

[0003] To address the lack of a low-cost and rapid method for evaluating the resistance to displacement and rotation of die-bonding adhesives in dense chip packaging, this application provides a method and system for evaluating the resistance of die-bonding adhesives to chip displacement and rotation.

[0004] This application is achieved through the following technical solution:

[0005] A method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation includes the following steps:

[0006] A standard LED bracket is selected, and the functional area of ​​the LED bracket can accommodate at least two chips;

[0007] At least two chips are placed in the functional area using a die bonder, and the spacing between adjacent chips is adjusted to a preset spacing distance.

[0008] Die-bonding adhesive is applied to the bottom of each chip using a dispensing process, so that the die-bonding adhesive covers the four sides of the bottom of the chip;

[0009] After allowing the chip to stand for a preset reaction time, observe whether the chip shifts or rotates.

[0010] If the chip position remains stable, the die-bonding adhesive is determined to have resistance to displacement and rotation; if the chip position is displaced or rotated, the die-bonding adhesive is determined to have insufficient resistance to displacement and rotation.

[0011] The method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation as described above, wherein the conventional LED bracket is a 2835 model bracket or a 5730 model bracket.

[0012] As described above, a method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation includes the step of the die-bonding adhesive covering the four sides of the bottom of the chip, wherein the distance between the edge of the die-bonding adhesive and the corresponding boundary of the bottom of the chip is S, and S≤10μm.

[0013] In the method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation as described above, the preset interval distance is 80±10μm.

[0014] In the method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation as described above, the preset reaction time is 30±5 seconds.

[0015] As described above, a method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation includes the step of observing whether the chip has shifted or rotated, which involves detecting the coordinate offset of the chip using an optical microscope or an automatic image recognition system.

[0016] As described above, in a method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation, the criteria for determining whether the chip has undergone displacement or rotation include:

[0017] Observe whether the positional offset of the chip's center position relative to its initial position is ≥2μm; or whether the rotation angle deflection is ≥1°.

[0018] The method described above for evaluating the resistance of die-bonding adhesive to chip displacement and rotation, wherein the chip has a size of 24±5mil*8±5mil.

[0019] A system for evaluating the resistance of die-attach adhesive to chip displacement rotation, for implementing the method for evaluating the resistance of die-attach adhesive to chip displacement rotation as described in any of the preceding claims, the system comprising:

[0020] The die bonding and positioning module is used to fix a conventional LED bracket and automatically arrange at least two chips in its functional area with a spacing of 80±10μm.

[0021] The dispensing module is used to dispense adhesive to each chip in the functional area so that the die bonding adhesive covers the four sides of the bottom of the chip.

[0022] The static observation module is used to allow the chip to stand still for 30 seconds after the die bonding operation is completed, and to determine whether the chip has moved or deflected by observing it with a microscope and a chip position detection instrument. Then, the anti-chip displacement and rotation performance of the die bonding adhesive is evaluated based on the judgment result.

[0023] Compared with the prior art, this application has the following advantages:

[0024] This application discloses a method and system for evaluating the resistance of die-bonding adhesive to chip displacement and rotation. By using a conventional LED bracket and precisely controlling the spacing between adjacent chips to a preset interval, and combining this with a dispensing process to ensure that the die-bonding adhesive completely covers the four sides of the bottom of the chip, the chip displacement or rotation can be directly observed after a preset reaction time. This method achieves low-cost and high-efficiency characterization of the resistance of die-bonding adhesive to displacement and rotation in non-COB dense packaging environments. By saving the use of a dedicated COB bracket, the testing cost is significantly reduced, and the actual use environment of dense chips can be conveniently simulated. The method is simple to operate, the evaluation is rapid, and the results are intuitive and reliable. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart of an embodiment of the present application for evaluating the method of using die-bonding adhesive to resist chip displacement and rotation;

[0027] Figure 2 This is a structural block diagram of the die-bonding adhesive system for evaluating chip displacement and rotation according to an embodiment of this application;

[0028] Figure 3 This is a schematic diagram illustrating the good anti-chip displacement effect of the die-bonding adhesive in the embodiments of this application;

[0029] Figure 4 This is a schematic diagram illustrating the poor anti-chip displacement effect of the die-bonding adhesive in the embodiments of this application. Figure 1 ;

[0030] Figure 5 This is a schematic diagram illustrating the poor anti-chip displacement effect of the die-bonding adhesive in the embodiments of this application. Figure 2 ;

[0031] Figure 6 This is a schematic diagram of the die-bonding adhesive covering the four sides of the bottom of the chip according to an embodiment of this application;

[0032] Figure 7 It corresponds Figure 3 Microscopic view;

[0033] Figure 8 It corresponds Figure 4 Microscopic view;

[0034] Figure 9 It corresponds Figure 5 Microscopic view. Detailed Implementation

[0035] To make the technical problems solved by this application, the technical solutions, and the beneficial effects clearer, this application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0036] Please see Figures 1 to 9 A method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation includes the following steps:

[0037] S1: Select a conventional LED bracket 1, the functional area 11 of the LED bracket 1 can accommodate at least two chips 2;

[0038] S2: At least two chips 2 are placed in the functional area 11 by a die bonder, and the spacing between adjacent chips 2 is adjusted to a preset spacing distance;

[0039] S3: Apply die-bonding adhesive 3 to the bottom of each chip 2 using a dispensing process, so that the die-bonding adhesive 3 covers the four sides of the bottom of the chip 2;

[0040] S4: After a preset reaction time, observe whether the chip 2 has shifted or rotated;

[0041] S5: If the position of the chip 2 remains stable, it is determined that the die bonding adhesive 3 has the ability to resist displacement and rotation; if the position of the chip 2 is displaced or rotated, it is determined that the ability of the die bonding adhesive 3 to resist displacement and rotation is not up to standard.

[0042] This application discloses a method and system for evaluating the resistance of die-bonding adhesive to chip displacement and rotation. By using a conventional LED bracket and precisely controlling the spacing between adjacent chips to a preset interval, and combining this with a dispensing process to ensure that the die-bonding adhesive completely covers the four sides of the bottom of the chip, the chip displacement or rotation can be directly observed after a preset reaction time. This method achieves low-cost and high-efficiency characterization of the resistance of die-bonding adhesive to displacement and rotation in non-COB dense packaging environments. By saving the use of a dedicated COB bracket, the testing cost is significantly reduced, and the actual use environment of dense chips can be conveniently simulated. The method is simple to operate, the evaluation is rapid, and the results are intuitive and reliable.

[0043] Furthermore, as a preferred embodiment of this solution and not a limitation, the conventional LED bracket 1 is a 2835 model bracket or a 5730 model bracket.

[0044] In this embodiment, since conventional LED brackets are widely used in the LED packaging industry, using these brackets for evaluation can avoid wasting chips and eliminate the need to use COB brackets for evaluation and testing, effectively reducing evaluation costs.

[0045] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the step of covering the four sides of the bottom of the chip 2 with the die bonding adhesive 3 includes: the distance between the edge of the die bonding adhesive 3 and the corresponding bottom boundary of the chip 2 is S, wherein S≤10μm.

[0046] In this embodiment, by strictly controlling the distance between the edge of the die-bonding adhesive 3 and the bottom boundary of the chip 2, a uniform and thin coating layer of adhesive can be formed on the bottom of the chip, effectively reducing the fluidity and diffusion of the adhesive. This prevents excessive adhesive flow during die bonding, thus avoiding displacement or rotation of the chip 2. Simultaneously, a smaller distance S≤10μm ensures sufficient contact area between the chip 2 and the die-bonding adhesive 3, providing good adhesion and mechanical stability. Precise control of the adhesive coverage area effectively avoids chip 2 displacement or rotation caused by adhesive flow, thereby improving packaging quality and reliability. Furthermore, a smaller distance S≤10μm also reduces the amount of adhesive used, lowers material costs, improves packaging efficiency, and shortens the production cycle.

[0047] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the preset interval distance is 80±10μm.

[0048] In this embodiment, the preset spacing distance is set based on the actual COB dense chip packaging scenario, which can simulate the typical spacing of chips in high-density arrangement. During the die bonding process, when the chip spacing is 80±10μm, the die bonding adhesive has sufficient space to flow between adjacent chips, but will not fail to form effective adhesion due to excessive spacing. This effectively balances the flowability of the adhesive and the stability of the chips, thereby accurately evaluating the die bonding adhesive's resistance to chip displacement and rotation while simulating the actual packaging process. The preset spacing distance of 80±10μm ensures the reliability and representativeness of the experimental results. This spacing range can simulate the common dense chip arrangement in actual production, while avoiding mutual interference between chips due to excessively small spacing or adhesive waste due to excessively large spacing. By evaluating the performance of the die bonding adhesive at this spacing, suitable die bonding adhesives for high-density packaging can be quickly screened, thereby improving packaging efficiency and product quality.

[0049] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the preset response time is 30±5 seconds.

[0050] In this embodiment, the preset reaction time range is designed to ensure that the die-bonding adhesive has sufficient time to initially cure after being applied to the bottom of the chip, thereby forming a stable bond, while not being too long and affecting production efficiency. A reaction time of approximately 30 seconds allows the die-bonding adhesive to fully wet the bottom of the chip and begin to cure, thus fixing the chip position quickly and preventing displacement or rotation in subsequent processes. Furthermore, an allowable error range of ±5 seconds can accommodate different environmental conditions (such as temperature and humidity variations) or operational differences, ensuring the stability and repeatability of experimental results. This significantly improves the efficiency of the packaging process, making it particularly suitable for large-scale production scenarios. Simultaneously, by precisely controlling the reaction time, chip displacement or rotation problems caused by incomplete or over-curing of the adhesive can be reduced, thereby improving the yield and reliability of the packaging.

[0051] Furthermore, as a preferred embodiment of this solution and not a limitation thereof, the step of observing whether the chip 2 has been displaced or rotated includes: detecting the coordinate offset of the chip 2 using an optical microscope or an automatic image recognition system.

[0052] In this embodiment, an optical microscope provides high-magnification observation, allowing for clear observation of minute displacements or rotations of the chip. Meanwhile, an automatic image recognition system uses image processing algorithms to quickly and accurately calculate the chip's coordinate offset. Combining these two detection methods leverages both the high precision of the optical microscope and the efficiency and automation of the automatic image recognition system, enabling rapid and accurate detection of chip position changes. Using either an optical microscope or an automatic image recognition system significantly improves detection accuracy and efficiency. The optical microscope provides intuitive images, helping technicians quickly determine if the chip has shifted or rotated, while the automatic image recognition system automatically calculates the offset using algorithms, reducing human error and improving repeatability and reliability. Furthermore, this detection method allows for automated detection, greatly shortening detection time and increasing production efficiency, making it particularly suitable for large-scale production environments.

[0053] Furthermore, as a preferred embodiment of this solution and not a limitation, the criteria for determining whether the chip 2 has undergone displacement or rotation include:

[0054] Observe whether the positional offset of the center position of chip 2 relative to the initial position is ≥2μm; or whether the rotation angle deflection is ≥1°.

[0055] In this embodiment, the standard is based on the minute displacement and rotation phenomena that may occur during the chip bonding process. By setting specific numerical thresholds (2μm and 1°), it provides a quantitative and operable basis for detecting and evaluating the resistance to displacement and rotation of the die-bonding adhesive. Position offset and rotation angle are important parameters for measuring the stability of the chip during the die-bonding process. By accurately measuring these parameters and comparing them with the set thresholds, it is possible to quickly determine whether the die-bonding adhesive can effectively fix the chip, thereby ensuring the reliability of the package. Clear quantitative indicators can avoid errors caused by subjective judgment, ensuring the repeatability and reliability of each experimental result. At the same time, the 2μm position offset and 1° rotation angle as thresholds can reflect the minute displacement and rotation that may occur during the actual packaging process without being too stringent and affecting the feasibility and efficiency of the experiment. This standard setting can effectively screen out die-bonding adhesives with excellent resistance to displacement and rotation, thereby improving packaging quality and reducing problems such as poor soldering or electrical short circuits caused by chip displacement or rotation.

[0056] Furthermore, as a preferred embodiment of this solution and not a limitation, the chip size is 24±5mil*8±5mil.

[0057] In this embodiment, the chip size of 24±5mil × 8±5mil is designed based on the versatility and adaptability requirements of chip size in actual packaging processes. This size range works by accommodating chip layout requirements in different packaging scenarios while ensuring chip stability and reliability during die bonding. The 24mil × 8mil baseline size is a commonly used medium size suitable for most conventional packaging processes, while the ±5mil tolerance allows for some dimensional fluctuations during manufacturing, thereby improving chip versatility and compatibility.

[0058] A system for evaluating the resistance of die-attach adhesive to chip displacement rotation, for implementing the method for evaluating the resistance of die-attach adhesive to chip displacement rotation as described in any of the preceding claims, the system comprising:

[0059] The die bonding and positioning module 4 is used to fix the conventional LED bracket 1 and automatically arrange at least two chips 2 in its functional area 11 with a spacing of 80±10μm.

[0060] The dispensing module 5 is used to dispense adhesive to each chip 2 in the functional area 11 so that the die bond adhesive 3 covers the four sides of the bottom of the chip 2.

[0061] The static observation module 6 is used to allow the chip 2 to stand still for 30 seconds after the die bonding operation is completed, and to determine whether the chip 2 has moved or deflected by observing it with a microscope and a chip position detection instrument. Then, based on the judgment result, the anti-chip displacement and rotation performance of the die bonding adhesive 3 is evaluated.

[0062] In this embodiment, the system significantly improves evaluation efficiency and accuracy. Automated placement and dispensing reduce human error and ensure consistent experimental conditions for each test. Simultaneously, the static observation module, combined with the use of a microscope or other testing instruments, enables rapid and accurate determination of chip displacement and rotation, providing reliable data support for the performance evaluation of the die-bonding adhesive. Furthermore, the system design is adaptable to different types of chips and die-bonding adhesives, exhibiting good versatility and scalability.

[0063] The working principle of this embodiment is as follows:

[0064] This application discloses a method and system for evaluating the resistance of die-bonding adhesive to chip displacement and rotation. By using a conventional LED bracket and precisely controlling the spacing between adjacent chips to a preset interval, and combining this with a dispensing process to ensure that the die-bonding adhesive completely covers the four sides of the bottom of the chip, the chip displacement or rotation can be directly observed after a preset reaction time. This method achieves low-cost and high-efficiency characterization of the resistance of die-bonding adhesive to displacement and rotation in non-COB dense packaging environments. By saving the use of a dedicated COB bracket, the testing cost is significantly reduced, and the actual use environment of dense chips can be conveniently simulated. The method is simple to operate, the evaluation is rapid, and the results are intuitive and reliable.

[0065] The above are implementation methods provided in conjunction with specific content, and it is not intended that the specific implementation of this application is limited to these descriptions. Any methods or structures that are similar to those of this application, or any technical deductions or substitutions made based on the concept of this application, should be considered within the scope of protection of this application.

Claims

1. A method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation, characterized in that, Includes the following steps: A conventional LED bracket (1) is selected, and the functional area (11) of the LED bracket (1) can accommodate at least two chips (2). At least two chips (2) are placed in the functional area (11) by a die bonder, and the spacing between adjacent chips (2) is adjusted to a preset spacing distance; Die-bonding adhesive (3) is applied to the bottom of each chip (2) by dispensing, so that the die-bonding adhesive (3) covers the four sides of the bottom of the chip (2); After allowing the chip to stand for a preset reaction time, observe whether the chip (2) is displaced or rotated. If the position of the chip (2) remains stable, it is determined that the die bonding adhesive (3) has the ability to resist displacement and rotation; if the position of the chip (2) is displaced or rotated, it is determined that the die bonding adhesive (3) does not meet the requirements for resisting displacement and rotation. The preset interval distance is 80±10μm.

2. The method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation according to claim 1, characterized in that, The conventional LED bracket (1) is either the 2835 model bracket or the 5730 model bracket.

3. The method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation according to claim 1, characterized in that, The step of covering the four sides of the bottom of the chip (2) with the die bonding adhesive (3) includes: the distance between the edge of the die bonding adhesive (3) and the corresponding bottom boundary of the chip (2) is S, where S≤10μm.

4. The method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation according to claim 1, characterized in that, The preset reaction time is 30±5 seconds.

5. The method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation according to claim 1, characterized in that, The step of observing whether the chip (2) has been displaced or rotated includes: detecting the coordinate offset of the chip (2) by means of an optical microscope or an automatic image recognition system.

6. The method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation according to claim 1, characterized in that, The criteria for determining whether the chip (2) has shifted or rotated include: Observe whether the position offset of the center position of the chip (2) relative to the initial position is ≥2μm; or whether the rotation angle deflection is ≥1°.

7. The method for evaluating the resistance of die-bonding adhesive to chip displacement and rotation according to claim 1, characterized in that, The chip measures 27.4±5mil * 9.8±5mil.

8. A system for evaluating the resistance of die-bonding adhesive to chip displacement rotation, used to implement the method for evaluating the resistance of die-bonding adhesive to chip displacement rotation as described in any one of claims 1-7, characterized in that, The system includes: The die bonding and positioning module (4) is used to fix the conventional LED bracket (1) and automatically arrange at least two chips (2) in its functional area (11) with a spacing of 80±10μm. The dispensing module (5) is used to dispense adhesive to each chip (2) in the functional area (11) so that the die bond adhesive (3) covers the four sides of the bottom of the chip (2); The static observation module (6) is used to allow the chip (2) to stand still for 30 seconds after the die bonding operation is completed, and to determine whether the chip (2) has moved or deflected by observation under a microscope and a chip position detection instrument, and then to evaluate the anti-chip displacement and rotation performance of the die bonding adhesive (3) based on the judgment result.

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