Hybrid die bonding method for pixels

Abstract

This application proposes a hybrid die bonding method for pixels, comprising the following steps: S1, dividing the die bonding surface of a substrate into multiple pixel positions, each pixel position including three die bonding positions, namely a first die bonding position, a second die bonding position, and a third die bonding position; S2, obtaining the positions of the first die bonding position, the second die bonding position, and the third die bonding position of the pixel position to be die bonded on the substrate; S3, a first die bonding device fixing a wafer of a first color on the first die bonding position of the pixel position; S4, a second die bonding device fixing a wafer of a second color on the second die bonding position of the pixel position; S5, a third die bonding device fixing a wafer of a third color on the third die bonding position of the pixel position; S6, obtaining the positions of the first die bonding position, the second die bonding position, and the third die bonding position of the next pixel position on the substrate, and performing steps S3-S5 sequentially; S7, repeating step S6 until all pixel positions on the substrate have been die bonded; this method can improve die bonding efficiency.

Description

Technical Field

[0001] This application relates to the field of die bonding technology, and more particularly to a hybrid die bonding method for pixels. Background Technology

[0002] like Figure 1 As shown, the traditional die bonding method for display substrates is as follows: first, a single-color chip, such as a red chip, is fixed onto the substrate; then, the substrate is removed and clamped onto another die bonding machine; next, a chip of another color, such as a green chip, is fixed; after all the green chips are fixed, the substrate is removed and clamped onto another die bonding machine to fix the last color chip, such as a blue chip. Obviously, the traditional die bonding method for display substrates is a mixed bonding method. This mixed bonding method requires three machine changes and re-clamping of the substrate (including the initial substrate clamping action). This will prolong the die bonding time, reduce the bonding efficiency, and increase the labor intensity of the workers. In addition, there are certain differences in the shape, size, and surface reflectivity of the chips on different wafers. When using the above mixed bonding method, the vision positioning system of the die bonding machine needs to reposition the substrate when re-clamping it. This will lead to difficulties in substrate positioning and matching, reduced accuracy, and even misjudgment. Summary of the Invention

[0003] The purpose of this application is to provide a hybrid die bonding method for pixels, which can improve die bonding efficiency, reduce labor costs for workers, and eliminate the problem of difficult substrate positioning.

[0004] Therefore, this application provides a hybrid die bonding method for pixels, based on three die bonding devices: a first die bonding device, a second die bonding device, and a third die bonding device. The die bonding method includes the following steps:

[0005] S1. A plurality of pixel positions are divided on the die-bonding surface of the substrate, and each pixel position includes three die-bonding positions, namely a first die-bonding position, a second die-bonding position and a third die-bonding position.

[0006] S2. Obtain the positions of the first die-bonding position, the second die-bonding position, and the third die-bonding position of the pixel position to be die-bonded on the substrate.

[0007] S3. The first die bonding device fixes a chip of the first color at the first die bonding position of the pixel.

[0008] S4. The second die bonding device fixes a chip of the second color at the second die bonding position of the pixel.

[0009] S5. The third die bonding device fixes a wafer of the third color at the third die bonding position of the pixel.

[0010] S6. Obtain the positions of the first die-bonding position, the second die-bonding position, and the third die-bonding position of the next pixel on the substrate, and perform steps S3-S5 in sequence.

[0011] S7. Repeat step S6 until all pixel positions on the substrate have been die-bonded.

[0012] This application proposes a hybrid die bonding method for pixels, which has the following advantages compared with the prior art:

[0013] This method can fix three wafers (red wafer, green wafer and blue wafer) sequentially on a single pixel, and can perform die bonding pixel by pixel without changing the machine. This can improve die bonding efficiency, reduce labor costs for workers, and eliminate the problem of difficult substrate positioning. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, in the drawings, the same parts use the same reference numerals, and the drawings are not drawn to scale.

[0015] Figure 1 This is a process diagram of the traditional pixel-based solidification method;

[0016] Figure 2 This is a process diagram of the pixel-mixing die bonding method of this approach;

[0017] Figure 3 and Figure 4 This is another process diagram of the pixel-mixing die bonding method of this approach; Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] This application proposes a hybrid die bonding method for pixels, based on three die bonding devices: a first die bonding device, a second die bonding device, and a third die bonding device. The die bonding method includes the following steps:

[0020] S1. Multiple pixel positions are divided on the die-bonding surface of the substrate, and each pixel position includes three die-bonding positions, namely the first die-bonding position, the second die-bonding position and the third die-bonding position.

[0021] S2. Obtain the positions of the first die-bonding position, the second die-bonding position, and the third die-bonding position of the pixel position to be die-bonded on the substrate.

[0022] S3. The first die bonding device fixes the chip of the first color at the first die bonding position of the pixel;

[0023] S4. The second die bonding device fixes the chip of the second color at the second die bonding position of the pixel.

[0024] S5. The third die bonding device fixes the chip of the third color at the third die bonding position of the pixel.

[0025] S6. Obtain the positions of the first die-bonding position, the second die-bonding position, and the third die-bonding position of the next pixel on the substrate, and perform steps S3-S5 in sequence.

[0026] S7. Repeat step S6 until all pixel positions on the substrate have been die-bonded.

[0027] Based on the above technical solution, this method can fix three wafers (red wafer, green wafer and blue wafer) in a single pixel position, and can perform die bonding pixel by pixel without changing the machine, which can improve die bonding efficiency, reduce labor costs for workers, and eliminate the problem of substrate positioning difficulties.

[0028] In this application, the first die bonding device includes a first robotic arm, a first material box, and a first mounting structure; the second die bonding device includes a second robotic arm, a second material box, and a second mounting structure; and the third die bonding device includes a third robotic arm, a third material box, and a third mounting structure. That is, the first, second, and third die bonding devices can all be existing die bonding mechanisms. Therefore, step S7 includes:

[0029] S71. Repeat step S6 until all wafers on the first mounting structure, the second mounting structure, and the third mounting structure are used up.

[0030] S72. The first robotic arm replaces the wafer ring in the first material box onto the first mounting structure;

[0031] S73, The second robotic arm replaces the wafer ring in the second material box onto the second mounting structure;

[0032] S74. The third robotic arm replaces the wafer ring in the third material box onto the third mounting structure.

[0033] S75. Repeat steps S71, S72, S73 and S74 until all pixel positions on the substrate have been die-bonded.

[0034] Before proceeding to step S1, the following steps must be performed:

[0035] S8. Install wafer rings of different colors on the first mounting structure, the second mounting structure, and the third mounting structure.

[0036] Traditional pixel bonding methods for display substrates require first bonding a single color (taking wafers from different wafer rings of the same color for bonding), and then bonding the second color. In this case, the size, shape, and reflective color of the previously bonded wafers may differ, which can affect the subsequent bonding positioning. However, this application involves bonding a single color in one step—bonding the red, green, and blue wafers in a pixel sequentially. When bonding again, the pixel is empty, and the differences in wafer size, shape, and reflective color do not affect the subsequent bonding process.

[0037] For ease of description, the substrate is simulated using a 4*4 pixel module for die bonding, totaling 16 pixels, and a 4-ring mixed bonding process is employed; where 1-1, ..., 4-4 represent row and column numbers; the distance between each pixel, such as from pixel 1-1 to pixel 1-2, or from pixel 1-1 to pixel 2-1, is one pitch; within the same pixel, the distance between 1-1R and 1-1G is 0.2 pitches; R1, R2, R3, and R4 represent the red rings 1, 2, 3, and 4 respectively, and G and B represent green and blue respectively. The simulation process of the traditional mixed bonding method is as follows: Figure 1 As shown, the time consumption is calculated as follows:

[0038] In the traditional mixed-solidification method, the total substrate movement distance is: 2 spacings * 3 single rings * 4 rings * 3 colors = 72 spacings each time. This requires 9 ring changes, 3 machine changes, and 3 re-clamping of the substrate. Assuming a spacing of 1.25mm, typically moving a single spacing takes 0.03 seconds, changing a ring takes 10 seconds, and changing the machine and re-clamping takes 30 seconds. Therefore, the total time required for the above process is 72 * 0.03 + 9 * 10 + 3 * 30 = 182.16 seconds. This process assumes automatic ring changing and automatic machine clamping. If manual replacement is used, the time will be even longer.

[0039] Currently, the size of a single substrate on the market is generally 20,000 pixels. Therefore, the total time taken for the above process is 72*0.03*(20000 / 16)+9*10+3*30=2880 seconds.

[0040] In this method, since a single die bonding device has three colors of wafer rings, and the switching of the three colors of wafer rings can be performed simultaneously, the simulation process is as follows: Figure 2 As shown, the time consumption is calculated as follows:

[0041] The total substrate movement distance is: [0.2 spacings per color * 2 single rings + 2.1] * 3 pixel jumps * 4 = 30 spacings, requiring 3 ring changes, but no machine change is needed. Similarly, with a spacing of 1.25mm, it typically takes 0.03 seconds to move a single spacing and 10 seconds to change a ring. Therefore, the total time required for the above process is 30 * 0.03 + 3 * 10 = 30.9 seconds, which is nearly 83% less than the 182.16 seconds of the traditional pixel mixing method. Calculated with 20,000 pixels on a single substrate, the total pixel mixing process time of this method is 30 * 0.03 * (20000 / 16) + 3 * 10 = 1155 seconds, which is nearly 60% less than the 2880 seconds of the traditional pixel mixing method.

[0042] The above data are only calculated values ​​when a single substrate uses 4-ring mixing and solidification. In this method, a single machine can store 12 wafer rings for a single color, and 36 wafer rings for 3 colors. When a single substrate uses 12-ring mixing and solidification for a single color, the time occupied by changing rings and changing machines will increase exponentially. Therefore, the advantages of this die bonding method will be more prominent.

[0043] In the above data, the spacing between two adjacent pixels is 1.25mm, which is a common setting in the die bonding process. Different spacing between two adjacent pixels results in different time consumption for this die bonding method and the traditional mixed-solid method, but the ratio of the time consumption of this die bonding method to the time consumption of the traditional mixed-solid method does not fluctuate much.

[0044] This method obtains the die-bonding position through a vision camera. Alternatively, the camera can be omitted for positioning. The XY coordinates of the pixel to be bonded can be obtained in advance by using internal software programming or importing coordinate positions from external files. Then, the die-bonding stage moves to the specified pixel position according to the coordinate values ​​to perform blind die bonding.

[0045] In this method, step S3 is as follows:

[0046] Based on the shape of the first die-bonding position of the pixel, the position of the first mounting structure is corrected to correct the wafer position of the wafer ring thereon, and the wafer on the wafer ring is fixed on the first die-bonding position by the swing arm.

[0047] The process of step S4 is as follows:

[0048] Based on the shape of the second die-bonding position of the pixel, the position of the second mounting structure is corrected to correct the wafer position of the wafer ring thereon, and the wafer on the wafer ring is fixed on the second die-bonding position by a swing arm;

[0049] The process of step S5 is as follows:

[0050] Based on the shape of the third die-bonding position of the pixel, the position of the third mounting structure is corrected to correct the wafer position of the wafer ring thereon, and the wafer on the wafer ring is fixed on the third die-bonding position by a swing arm.

[0051] This ensures that the chip can fit the shape of the die bonding site and will not exceed the range defined by the die bonding site, thus guaranteeing the quality of die bonding.

[0052] Furthermore, step S7 also includes the following processes:

[0053] S76. While repeating step S6, eliminate static electricity from the wafer rings on the first mounting structure, the second mounting structure, and the third mounting structure.

[0054] This prevents static electricity from affecting the quality of die bonding. In this application, a plasma fan is installed above the first, second, and third mounting structures to blow out air and remove static electricity. Other methods of static removal can also be used, which will not be listed here.

[0055] Step S7 also includes:

[0056] S77. Check whether the first mounting structure is a wafer ring that has not been die bonded. If not, repeat step S72.

[0057] S78. Check whether the second mounting structure is a wafer ring that has not been die bonded. If not, repeat step S73.

[0058] S79. Check whether the third mounting structure is a wafer ring that has not been die bonded. If not, repeat step S74.

[0059] This ensures that the die bonding process can proceed smoothly.

[0060] Specifically, the wafers on the first die bonding device, the second die bonding device, and the third die bonding device may have the same or different specifications. The substrate used in this application is a display substrate. By selecting wafers of different colors but the same specifications for die bonding, the display effect of the display can be guaranteed. In addition, the pixel positions on the substrate are distributed in an array, but the three die bonding positions on one pixel position are adjacent to each other.

[0061] In this method, step S1 further includes the following steps:

[0062] S11. Label each pixel individually;

[0063] S12. Randomly sort these pixels using the program and generate a random die bonding path file;

[0064] S13. Perform die bonding on the substrate according to the random die bonding path file.

[0065] The first and next pixel positions during die bonding can be random. A random die bonding path file can be generated by a computer program, and then die bonding can be performed according to the pixel position sequence specified in the file, so that the die bonding positions are more dispersed and the wafer position on the substrate is more uniformly mixed.

[0066] like Figures 3-4 As shown, the simulation process is deduced using the 4*4 matrix mentioned above: 1-1…4-4 represent the row and column numbers; the distance from pixel 1-1 to pixel 1-2 and from pixel 1-1 to pixel 2-1 is 1 (a spacing), and the distance from 1-1R to 1-1G is 0.2 (a spacing); R1, R2, R3, and R4 represent the red rings 1, 2, 3, and 4, respectively; (G / B represent green and blue, respectively).

[0067] According to the requirements for random file mixing, the same machine can mix three colors, and the number in front of the pixel indicates the order of the pixel in the random file.

[0068] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0069] It should be readily understood that the terms “on,” “above,” and “on top of” in this disclosure should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on top of something” but also “on top of something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0070] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90 degrees or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0071] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A hybrid die bonding method for pixels, based on three die bonding devices, namely a first die bonding device, a second die bonding device, and a third die bonding device, characterized in that, The die bonding method includes the following steps: S1. A plurality of pixel positions are divided on the die-bonding surface of the substrate, and each pixel position includes three die-bonding positions, namely a first die-bonding position, a second die-bonding position and a third die-bonding position. S2. Obtain the positions of the first die-bonding position, the second die-bonding position, and the third die-bonding position of the pixel position to be die-bonded on the substrate. S3. The first die bonding device fixes a chip of the first color at the first die bonding position of the pixel. S4. The second die bonding device fixes a chip of the second color at the second die bonding position of the pixel. S5. The third die bonding device fixes a wafer of the third color at the third die bonding position of the pixel. S6. Obtain the positions of the first die-bonding position, the second die-bonding position, and the third die-bonding position of the next pixel on the substrate, and perform steps S3-S5 in sequence. S7. Repeat step S6 until all pixel positions on the substrate have been die-bonded. The first die bonding device includes a first robotic arm, a first material box, and a first mounting structure; the second die bonding device includes a second robotic arm, a second material box, and a second mounting structure; and the third die bonding device includes a third robotic arm, a third material box, and a third mounting structure. The process of step S7 is characterized by comprising: S71. Repeat step S6 until all wafers on the first mounting structure, the second mounting structure, and the third mounting structure are used up. S72, The first robotic arm replaces the wafer ring in the first material box onto the first mounting structure; S73, The second robotic arm replaces the wafer ring in the second material box onto the second mounting structure; S74. The third robotic arm replaces the wafer ring in the third material box onto the third mounting structure; S75. Repeat steps S71, S72, S73 and S74 until all pixel positions on the substrate have been die-bonded. Before proceeding to step S1, the following steps must be performed: S8. Install wafer rings of different colors on the first mounting structure, the second mounting structure and the third mounting structure; The process of step S3 is as follows: Based on the shape of the first die-bonding position of the pixel, the position of the first mounting structure is corrected to correct the wafer position of the wafer ring thereon, and the wafer on the wafer ring is fixed on the first die-bonding position by a swing arm. The process of step S4 is as follows: Based on the shape of the second die-bonding position of the pixel, the position of the second mounting structure is corrected to correct the wafer position of the wafer ring thereon, and the wafer on the wafer ring is fixed on the second die-bonding position by a swing arm; The process of step S5 is as follows: Based on the shape of the third die-bonding position of the pixel, the position of the third mounting structure is corrected to correct the wafer position of the wafer ring thereon, and the wafer on the wafer ring is fixed on the third die-bonding position by a swing arm.

2. The pixel hybrid die bonding method according to claim 1, characterized in that, The step S7 also The process includes the following: S76. While repeating step S6, eliminate static electricity from the wafer rings on the first mounting structure, the second mounting structure, and the third mounting structure.

3. The pixel hybrid die bonding method according to claim 1, characterized in that, The process of step S7 also includes: S77. Check whether the first mounting structure is a wafer ring that has not been die bonded. If not, repeat step S72. S78. Check whether the second mounting structure is a wafer ring that has not been die bonded. If not, repeat step S73. S79. Check whether the third mounting structure is a wafer ring that has not been die bonded. If not, repeat step S74.

4. The pixel hybrid die bonding method according to claim 1, characterized in that, The wafers on the first die bonding device, the second die bonding device, and the third die bonding device may have the same or different specifications.

5. The pixel hybrid die bonding method according to claim 1, characterized in that, The pixels are distributed in an array.

6. The pixel hybrid die bonding method according to claim 1, characterized in that, Step S1 also includes the following steps: S11. Label each pixel individually; S12. Randomly sort these pixels using the program and generate a random die bonding path file; S13. Perform die bonding on the substrate according to the random die bonding path file.

7. The pixel hybrid die bonding method according to claim 1, characterized in that, The location of the solidification site is obtained using a vision camera.

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