Light emitting chip transfer method and display panel

Abstract

The application specifically relates to a light-emitting chip transfer method and a display panel, which comprises the following steps: providing a first substrate; providing a transfer substrate provided with a plurality of transfer units, wherein each transfer unit comprises a transfer hole and a butt joint hole, and the butt joint hole is arranged at the outer edge of the transfer hole; aligning the first substrate and the transfer substrate; providing a second substrate, wherein the fixed units on the second substrate comprise first connecting electrodes and second connecting electrodes, the end surface of the first connecting electrode is farther away from the substrate than the end surface of the second connecting electrode, part of the first connecting electrode corresponds to the first electrode, and the second connecting electrode corresponds to the second electrode; aligning the transfer substrate and the second substrate; removing the substrate; connecting the first connecting electrode and the second connecting electrode located in the transfer hole with the first electrode and the second electrode respectively; and removing the transfer substrate. The first connecting electrode is limited by the butt joint hole, the binding of the first electrode and the first connecting electrode is guaranteed, and the success rate of chip transfer is guaranteed.

Description

Technical Field

[0001] This application belongs to the field of display technology, specifically relating to a method for transferring light-emitting chips and a display panel. Background Technology

[0002] Micro-LED is a next-generation display technology. Compared with existing liquid crystal displays, it has higher photoelectric efficiency, higher brightness, higher contrast, and lower power consumption, and can also be combined with flexible panels to achieve flexible displays.

[0003] Micro-LED chips are light-emitting diode chips with a size of less than 100 micrometers. After fabrication, micro-LED chips typically undergo a mass transfer process, transferring a large number (usually tens to hundreds of thousands) of micro-LED chips onto a driver circuit board. However, current transfer processes can lead to misalignment between the electrodes on the LED chip and the connection electrodes on the driver circuit board, causing electrode bonding failure on both substrates and resulting in chip transfer failure. Summary of the Invention

[0004] The purpose of this application is to provide a method for transferring light-emitting chips and a display panel, which can improve the bonding success rate of electrodes on two substrates, thereby improving the chip transfer success rate.

[0005] The first aspect of this application provides a method for transferring a light-emitting chip, the method comprising:

[0006] A first substrate is provided, the first substrate including a substrate and a light-emitting chip, the light-emitting chip including a first electrode and a second electrode formed on the substrate and spaced apart from each other, wherein the end face of the first electrode away from the substrate is closer to the substrate than the end face of the second electrode away from the substrate;

[0007] A transfer substrate is provided, the transfer substrate having a plurality of transfer units, each transfer unit including transfer holes and docking holes that communicate with each other, the docking holes being located at the outer edge of the transfer holes, and the transfer holes corresponding to the light-emitting chip;

[0008] The first substrate and the transfer substrate are aligned so that the light-emitting chip is placed in the transfer hole;

[0009] A second substrate is provided, the second substrate including a substrate and a fixing unit disposed on the substrate, the fixing unit including a first connecting electrode and a second connecting electrode disposed at intervals from each other, one end of the first connecting electrode and one end of the second connecting electrode being disposed on the substrate, the end face of the first connecting electrode away from the substrate being further away from the substrate than the end face of the second connecting electrode away from the substrate, a portion of the first connecting electrode corresponding to the first electrode, and the second connecting electrode corresponding to the second electrode;

[0010] The transfer substrate with the light-emitting chip is aligned with the second substrate so that the first connecting electrode is aligned and inserted with the docking hole, with a part of the first connecting electrode located in the docking hole and the other part located in the transfer hole;

[0011] After aligning the transfer substrate with the light-emitting chip to the second substrate, the substrate is removed.

[0012] Connect the first connecting electrode located in the transfer hole to the first electrode, and connect the second connecting electrode to the second electrode in the transfer hole;

[0013] Remove the transfer substrate.

[0014] In an exemplary embodiment of this application, the docking holes are provided on opposite sides of the transfer hole, and the diameter of the docking holes is smaller than the diameter of the transfer hole; the fixing unit includes the second connecting electrode and the first connecting electrodes located on opposite sides of the second connecting electrode, and the two first connecting electrodes are symmetrical with respect to the second connecting electrode.

[0015] In one exemplary embodiment of this application, the first electrode is disposed around the second electrode.

[0016] In one exemplary embodiment of this application, the first electrode and the second electrode are arranged on the same axis.

[0017] In one exemplary embodiment of this application, the first substrate further includes a first semiconductor layer, a multiple quantum well layer, and a second semiconductor layer stacked sequentially. The first semiconductor layer is disposed on the side of the multiple quantum well layer close to the substrate, the first electrode is disposed on the side of the first semiconductor layer away from the substrate, and the second electrode is disposed on the side of the second semiconductor layer away from the substrate.

[0018] Wherein, the orthographic projection of the outer edge of the first electrode on the substrate and the orthographic projection of the outer edge of the first semiconductor layer on the substrate are spaced apart; the orthographic projection of the second electrode on the substrate is located within the orthographic projection of the second semiconductor layer on the substrate.

[0019] In one exemplary embodiment of this application, before aligning the transfer substrate with the transferred light-emitting chip to the second substrate, the light-emitting chip transfer method further includes:

[0020] At least one of the first connecting electrode and the second connecting electrode is provided with a welding element, the welding element being disposed on the side of the first connecting electrode or the second connecting electrode away from the substrate.

[0021] In one exemplary embodiment of this application, the welding element is provided on the side of both the first connecting electrode and the second connecting electrode away from the substrate.

[0022] In one exemplary embodiment of this application, the welding member is provided on the side of the first connecting electrode away from the substrate, one of the second connecting electrode and the second electrode is provided with a protrusion, and the other is provided with a groove, and the second connecting electrode and the second electrode are connected by the protrusion and the groove.

[0023] In one exemplary embodiment of this application, the first substrate further includes a transfer layer disposed on the side of the first electrode near the substrate.

[0024] A second aspect of this application provides a display panel, the display panel including a second substrate and a plurality of light-emitting chips, at least a portion of the plurality of light-emitting chips being transferred onto the second substrate by a light-emitting chip transfer method as described in any of the preceding claims.

[0025] The proposed solution has the following beneficial effects:

[0026] This application includes a method for transferring a light-emitting chip. In this method, a transfer substrate is provided, with transfer holes on the transfer substrate corresponding to the light-emitting chip on a first substrate. After aligning the first substrate and the transfer substrate, the first electrode and the second electrode on the light-emitting chip are positioned within the transfer holes. Then, after aligning the transfer substrate and the second substrate, the first connecting electrode and the second connecting electrode are placed within the mating hole and the transfer hole, respectively. In other words, the mating hole limits the first connecting electrode on the second substrate, and the transfer hole limits the second connecting electrode on the second substrate, ensuring the bonding of the first electrode and the first connecting electrode, as well as the bonding of the second electrode and the second connecting electrode, thereby ensuring a high success rate for chip transfer.

[0027] In addition, the present application also includes a display panel, and the transfer of light-emitting chips to the second substrate by the light-emitting chip transfer method has a higher success rate, thereby ensuring the display effect of the display panel.

[0028] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0029] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0031] Figure 1 The flowchart of the light-emitting chip transfer method provided in Embodiment 1, Embodiment 2 or Embodiment 3 of this application is shown;

[0032] Figure 2 This illustration shows a schematic diagram of a structure in which a light-emitting chip is provided on a first substrate according to Embodiment 1, Embodiment 2, or Embodiment 3 of this application;

[0033] Figure 3 This paper shows a top view of the structure of a first substrate with a light-emitting chip provided in Embodiment 1, Embodiment 2 or Embodiment 3 of this application;

[0034] Figure 4 The diagram shows a schematic diagram of the transfer substrate provided in Embodiment 1, Embodiment 2 or Embodiment 3 of this application;

[0035] Figure 5 This illustration shows a structural diagram of a second substrate with a fixing unit provided in Embodiment 1, Embodiment 2, or Embodiment 3 of this application;

[0036] Figure 6 This shows a schematic diagram of the alignment process between the transfer substrate with the light-emitting chip and the second substrate provided in Embodiment 1, Embodiment 2 or Embodiment 3 of this application;

[0037] Figure 7 This illustration shows a schematic diagram of the structure after the transfer substrate and the second substrate have been aligned and then the substrate and transfer layer have been removed, as provided in Embodiment 1, Embodiment 2 or Embodiment 3 of this application.

[0038] Figure 8This illustration shows a schematic diagram of the structure of transferring all the light-emitting chips to the second substrate according to Embodiment 1, Embodiment 2 or Embodiment 3 of this application;

[0039] Figure 9 The diagram shows a schematic diagram of the structure for removing the transfer substrate provided in Embodiment 1, Embodiment 2, or Embodiment 3 of this application;

[0040] Figure 10 This illustration shows a cross-sectional view of the second connecting electrode with a protrusion provided in Embodiment 1, Embodiment 2, or Embodiment 3 of this application.

[0041] Figure 11 This illustration shows a three-dimensional structure diagram of the second connecting electrode with protrusions provided in Embodiment 1, Embodiment 2, or Embodiment 3 of this application.

[0042] Explanation of reference numerals in the attached figures:

[0043] 10. First substrate; 11. Substrate; 12. Light-emitting chip; 12a. Red light-emitting chip; 12b. Green light-emitting chip; 12c. Blue light-emitting chip; 120. First electrode; 121. Second electrode; 122. First semiconductor layer; 123. Multiple quantum well layer; 124. Second semiconductor layer; 13. Transfer layer; 20. Transfer substrate; 21. Transfer unit; 210. Transfer hole; 211. Docking hole; 30. Second substrate; 31. Substrate; 32. Fixing unit; 320. First connecting electrode; 321. Second connecting electrode; 40. Welded component; 50. Protrusion. Detailed Implementation

[0044] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0045] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0046] In this application, unless otherwise expressly specified and limited, the terms "assembly," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0047] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0048] Example 1

[0049] Embodiment 1 of this application provides a method for transferring a light-emitting chip, which can improve the transfer success rate of the light-emitting chip 12 and ensure the light-emitting effect of the light-emitting chip 12. In this embodiment, the light-emitting chip 12 can be a Micro LED or a Mini LED.

[0050] See Figure 1 As shown, this light-emitting chip transfer method includes the following steps:

[0051] S100 provides a first substrate 10.

[0052] The first substrate 10 can be a substrate structure formed by directly growing on the wafer; or it can be a substrate structure in which the light-emitting chip 12 is transferred by attaching the light-emitting chip 12 to the first substrate 10 after growing the light-emitting chip 12 on the wafer.

[0053] See Figure 2 As shown in this embodiment, the first substrate 10 includes a substrate 11 and light-emitting chips 12. Multiple sets of light-emitting chips 12 are arranged in an array on the substrate 11. For example, the multiple sets of light-emitting chips 12 are arranged at intervals in the row and column directions on the substrate 11. Each set of light-emitting chips 12 includes a first electrode 120 and a second electrode 121 formed on the substrate 11 and spaced apart from each other. The end face of the first electrode 120 away from the substrate 11 is closer to the substrate 11 than the end face of the second electrode 121 away from the substrate 11.

[0054] The substrate 11 can be made of materials such as glass, sapphire, or quartz.

[0055] It should be understood that, see Figure 2 and Figure 3 As shown, when forming the first electrode 120 and the second electrode 121 on the substrate 11, this light-emitting chip transfer method further includes forming a first semiconductor layer 122, a multi-quantum well layer 123, and a second semiconductor layer 124 on the substrate 11. The first semiconductor layer 122, the multi-quantum well layer 123, and the second semiconductor layer 124 are sequentially stacked on the substrate 11. The multi-quantum well layer 123 is disposed between the first semiconductor layer 122 and the second semiconductor layer 124. The first semiconductor layer 122 is disposed on the side of the multi-quantum well layer 123 closer to the substrate 11. The first electrode 120 is located on the side of the first semiconductor layer 122 away from the substrate 11 and is electrically connected to the first semiconductor layer 122. The second electrode 121 is located on the side of the second semiconductor layer 124 away from the substrate 11 and is electrically connected to the second semiconductor layer 124.

[0056] It should be noted that the first electrode 120 can be an N-type electrode, and the second electrode 121 can be a P-type electrode; correspondingly, the first semiconductor layer 122 is an N-type semiconductor layer, and the second semiconductor layer is a P-type semiconductor layer. Of course, it is also possible that the first electrode 120 can be a P-type electrode, the second electrode 121 can be an N-type electrode, and correspondingly, the first semiconductor layer 122 can be a P-type semiconductor layer, and the second semiconductor layer can be an N-type semiconductor layer. The specific design can be made according to the specific embodiment.

[0057] In the embodiments of this application, see Figure 2 and Figure 3 As shown, the first electrode 120 is an N-type electrode, the second electrode 121 is a P-type electrode, the first semiconductor layer 122 is an N-type semiconductor layer, and the second semiconductor layer 124 is a P-type semiconductor layer. The projected area of ​​the first semiconductor layer 122 on the substrate 11 is greater than the projected area of ​​the multi-quantum well layer 123 on the substrate 11 and the projected area of ​​the second semiconductor layer 124 on the substrate 11. The projected areas of the multi-quantum well layer 123 and the second semiconductor layer 124 on the substrate 11 can be equal. The projected area of ​​the second electrode 121 on the substrate 11 is smaller than the projected area of ​​the second semiconductor layer 124 on the substrate 11. That is, the orthogonal projection of the second electrode 121 on the substrate 11 lies within the orthogonal projection of the second semiconductor layer 124 on the substrate 11, creating a gradient between the second electrode 121 and the second semiconductor layer 124. This reduces the flow of solder during the subsequent bonding process of the second electrode 121, thus preventing the solder flow from connecting the first electrode 120 and the second electrode 121 and causing a short circuit, ensuring the successful transfer rate of the light-emitting chip 12.

[0058] It should be noted that the area of ​​the multi-quantum well layer 123 can be larger than the area of ​​the second semiconductor layer 124, so that a gradient is formed between the second semiconductor layer 124 and the multi-quantum well layer 123. This can further reduce the flow of solder during the subsequent bonding process of the light-emitting chip 12, thereby avoiding the problem of short circuit caused by the solder flow connecting the first electrode 120 and the second electrode 121, and ensuring the success rate of the transfer of the light-emitting chip 12. That is, forming two different gradients between the multi-quantum well layer 123, the second semiconductor layer 124 and the second electrode 121 can reduce the flow rate and flow range of the solder, thereby avoiding problems such as short circuit caused by direct connection between the first electrode 120 and the second electrode 121.

[0059] In addition, see Figure 2 As shown, there is a height difference between the first electrode 120 and the second electrode 121 to further reduce the flow of solder during the bonding process of the light-emitting chip 12 and avoid short circuits between the electrodes. For example, the end face of the first electrode 120 away from the substrate 11 is closer to the substrate 11 than the end face of the second electrode 121 away from the substrate 11, that is, the second electrode 121 is higher than the first electrode 120.

[0060] It is worth mentioning that the first electrode 120 can be arranged around the second electrode 121. By circling, the contact area of ​​the electrode can be increased, making it easier to bond the light-emitting chip 12 in the subsequent bonding process.

[0061] It should be noted that the first electrode 120 and the second electrode 121 can be set with coaxial lines or with different axes.

[0062] In the embodiments of this application, see Figure 2 and Figure 3 As shown, the first electrode 120 and the second electrode 121 are arranged coaxially, that is, the orthographic projection of the first electrode 120 on the substrate 11 and the orthographic projection of the second electrode 121 on the substrate 11 are concentrically arranged, and the top view of the first electrode 120 is a ring structure, and the top view of the second electrode 121 is a circular structure.

[0063] For example, see Figure 2 and Figure 3As shown, the first electrode 120, the first semiconductor layer 122, the second electrode 121, the multi-quantum well layer 123, and the second semiconductor layer 124 can all adopt a cylindrical structure. The first semiconductor layer 122, the first electrode 120, the multi-quantum well layer 123, and the second semiconductor layer 124 are gradually formed along the thickness direction of the substrate 11. The first electrode 120, the multi-quantum well layer 123, and the second semiconductor layer 124 are spaced apart from each other, and there is a gap between the orthographic projection of the outer edge of the first electrode 120 onto the substrate 11 and the orthographic projection of the outer edge of the first semiconductor layer 122 onto the substrate 11. This creates a gradient between the first electrode 120 and the first semiconductor layer 122, preventing solder flow and short circuits.

[0064] In some embodiments, the top view of the second electrode 121 may be square, with the first electrode 120 surrounding it. The first electrode 120 may be a ring structure; or it may be a ring-shaped frame structure, i.e., parallel to the edge of the first electrode 120.

[0065] In addition, the top view of the second electrode 121 can also be a polygonal structure, and the first electrode 120 can be a circular structure or the same border structure as the second electrode 121. For example, the top view of the second electrode 121 is a hexagonal structure, the first electrode 120 adopts a hexagonal border structure, and the outer edges of the first electrode 120 and the second electrode 121 are parallel.

[0066] S200 provides a transfer substrate 20.

[0067] See Figure 4 As shown, the transfer substrate 20 can be made of materials such as glass, sapphire, or quartz. The transfer substrate 20 is provided with a plurality of transfer units 21, each transfer unit 21 including a transfer hole 210 and a docking hole 211 that are interconnected. The docking hole 211 is located at the outer edge of the transfer hole 210, and the transfer hole 210 corresponds to the light-emitting chip 12.

[0068] It should be noted that the opening area of ​​the transfer hole 210 is larger than the opening area of ​​the mating hole 211.

[0069] Furthermore, the transfer hole 210 and the docking hole 211 may or may not be through holes, and the specific design can be made according to different embodiments.

[0070] In the embodiments of this application, see Figure 4As shown, both the transfer hole 210 and the docking hole 211 are through holes. Furthermore, since the light-emitting chip 12 has a cylindrical structure, and the transfer hole 210 corresponds to the light-emitting chip 12, to avoid damage to the light-emitting chip 12, the transfer hole 210 is designed as a circular hole. The opening area of ​​the transfer hole 210 is larger than the maximum projected area of ​​the light-emitting chip 12. That is, when the light-emitting chip 12 is placed inside the transfer hole 210, a gap is left between the outer surface of the light-emitting chip 12 and the inner wall of the transfer hole 210.

[0071] Optionally, the diameter of the transfer hole 210 is 5 μm to 10 μm larger than the diameter of the light-emitting chip 12, for example, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm.

[0072] It is understandable that the transfer hole 210 can be designed according to the specific structure of the light-emitting chip 12. For example, if the light-emitting chip 12 has a square structure, the transfer hole 210 can be designed as a square structure; or if the light-emitting chip 12 has a triangular structure, the transfer hole 210 can be designed as a triangular structure.

[0073] In addition, the opening area of ​​the transfer hole 210 can also be equal to the maximum projected area of ​​the light-emitting chip 12.

[0074] S300, the first substrate 10 and the transfer substrate 20 are aligned so that the light-emitting chip 12 is placed in the transfer hole 210.

[0075] The side of the first substrate 10 with the light-emitting chip 12 is aligned with the transfer substrate 20. Since the transfer hole 210 and the docking hole 211 on the transfer substrate 20 are both through holes, the side of the transfer substrate 20 can be arbitrarily selected to align with the first substrate 10. After aligning the first substrate 10 and the transfer substrate 20, the light-emitting chip 12 is placed in the transfer hole 210 by pressing or pushing.

[0076] It is worth mentioning that, see Figure 2 As shown, in order to improve the transfer success rate between the first substrate 10 and the transfer substrate 20, the first substrate 10 also includes a transfer layer 13. The transfer layer 13 is designed for the entire surface and is located on the side of the first electrode 120 near the substrate 11. That is, the transfer layer 13 is located between the first semiconductor layer 122 and the substrate 11. The transfer layer 13 can be made of a weak adhesive material, such as polydimethylsiloxane (PDMS).

[0077] S400 provides a second substrate 30.

[0078] Among them, see Figure 5As shown, the second substrate 30 includes a substrate 31 and multiple sets of fixing units 32 disposed on the substrate 31. Each set of fixing units 32 corresponds to a light-emitting chip 12. That is, each set of fixing units 32 includes a first connecting electrode 320 and a second connecting electrode 321 disposed at intervals. One end of the first connecting electrode 320 and one end of the second connecting electrode 321 are both disposed on the substrate 31. The end face of the first connecting electrode 320 away from the substrate 31 is further away from the substrate 31 than the end face of the second connecting electrode 321 away from the substrate 31. That is, the height of the first connecting electrode 320 is greater than the height of the second connecting electrode 321, so as to avoid short circuit caused by solder flow during subsequent soldering bonding with the light-emitting chip 12, thus ensuring insulation.

[0079] It should be noted that, see Figure 5 As shown, the height difference between the first connecting electrode 320 and the second connecting electrode 321 is equal to the height difference between the first electrode 120 and the second electrode 121, so as to ensure that the first connecting electrode 320 is electrically connected to the first electrode 120 and the second connecting electrode 321 is electrically connected to the second electrode 121.

[0080] For example, the first connecting electrode 320 is an N-electrode, and the second connecting electrode 321 is a P-electrode. The height difference between the first connecting electrode 320 and the second connecting electrode 321 is between 4 μm and 18 μm; for example, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, and 18 μm.

[0081] Furthermore, a portion of the first connecting electrode 320 corresponds to the first electrode 120, and the second connecting electrode 321 corresponds to the second electrode 121.

[0082] It should be noted that the structure of the second connecting electrode 321 can correspond to the structure of the second electrode 121. That is, the second connecting electrode 321 adopts a cylindrical structure, and the area of ​​the second connecting electrode 321 can be larger than the area of ​​the second electrode 121, so as to increase the contact area between the second connecting electrode 321 and the second electrode 121 and improve the bonding success rate between the second connecting electrode 321 and the second electrode 121.

[0083] In addition, a fixing unit 32 on the second substrate 30 includes at least two first connecting electrodes 320. The first connecting electrodes 320 are located on one side of the second connecting electrode 321. In order to ensure the stability of the light-emitting chip 12, a fixing unit 32 is provided with at least two first connecting electrodes 320, and the two first connecting electrodes 320 are centrally symmetrical with respect to the second connecting electrode 321.

[0084] In this embodiment, each fixing unit 32 includes two cylindrical first connecting electrodes 320, located on opposite sides of the second connecting electrode 321. For example, multiple fixing units 32 are arranged at intervals in the row and column directions, and the two first connecting electrodes 320 and the second connecting electrode 321 are arranged at intervals in the row direction.

[0085] S500, see S500 Figure 6 As shown, the transfer substrate 20 with the light-emitting chip 12 is aligned with the second substrate 30 so that the first connecting electrode 320 is aligned and inserted with the docking hole 211. A part of the first connecting electrode 320 is located in the docking hole 211 and the other part is located in the transfer hole 210.

[0086] It is understood that two first connecting electrodes 320 are provided on opposite sides of the second connecting electrode 321, and the docking hole 211 corresponds to the first connecting electrode 320, that is, the docking hole 211 is provided at the opposite edge positions of the transfer hole 210. For example, multiple transfer units 21 are arranged in the row direction and column direction, and the two docking holes 211 and the transfer hole 210 are arranged sequentially in the row direction, and the docking hole 211 and the transfer hole 210 are interconnected.

[0087] Furthermore, when the transfer substrate 20 with the light-emitting chip 12 is aligned with the second substrate 30, the first connecting electrode 320 is aligned and inserted with the docking hole 211. A part of the first connecting electrode 320 is located in the docking hole 211 and another part is located in the transfer hole 210, so as to connect the first connecting electrode 320 with the first electrode 120.

[0088] It should be noted that the mating hole 211 can adopt the same structure as the first connecting electrode 320; alternatively, the mating hole 211 can also be a circular hole, a square hole or a polygonal hole.

[0089] In the embodiments of this application, see Figure 4 As shown, the docking hole 211 can be a round hole. The docking hole 211 and the transfer hole 210 intersect. A part of the first connecting electrode 320 is located in the docking hole 211, another part passes through the intersection of the docking hole 211 and the transfer hole 210, and the remaining part is located in the transfer hole 210 corresponding to the first electrode 120.

[0090] Before aligning the transfer substrate 20, on which the light-emitting chip 12 has been transferred, with the second substrate 30, the light-emitting chip transfer method further includes:

[0091] At least one of the first connecting electrode 320 and the second connecting electrode 321 is provided with a welding element 40, which is disposed on the side of the first connecting electrode 320 or the second connecting electrode 321 away from the substrate 31.

[0092] In the embodiments of this application, see Figure 5 As shown, both the first connecting electrode 320 and the second connecting electrode 321, which are located away from the substrate 31, are provided with welding parts 40 to improve the bonding stability of the connecting electrodes and the bonding success rate.

[0093] It should be noted that the soldering part 40 can be made of solder material, and solder or other conductive material can be directly applied to the side of the first connecting electrode 320 and the second connecting electrode 321 away from the substrate 31.

[0094] Furthermore, providing a mating hole 211 on the transfer substrate 20 can improve the alignment accuracy between the transfer substrate 20 and the second substrate 30, allowing the second substrate 30 to quickly align with the transfer substrate 20. When the first connecting electrode 320 and the first electrode 120 are connected and bonded by soldering, fumes will be generated at the bonding location. Providing a mating hole 211 on the transfer substrate 20 can also guide the fumes upwards for exhaust, thereby preventing the fumes from flowing onto the substrate 31. It can also prevent excessive soldering from isolating the surrounding fixing units 32 and preventing short circuits of the surrounding light-emitting chips 12.

[0095] It is understood that in this embodiment of the application, the first connecting electrode 320 has a higher plane than the second connecting electrode 321, which can promote the discharge of gas generated during soldering through the mating hole 211 and reduce solder flow, thus avoiding short circuit between the two connecting electrodes.

[0096] Furthermore, the alignment process in this step includes:

[0097] A portion of the first connecting electrode 320 is inserted into the mating hole 211, and another portion is inserted into the transfer hole 210. The second connecting electrode 321 is fully inserted into the transfer hole 210.

[0098] S600, see S600 Figure 7 As shown, after aligning the transfer substrate 20 with the light-emitting chip 12 and the second substrate 30, the substrate 11 is removed.

[0099] The substrate 11 and transfer layer 13 on the first substrate 10 are removed using a laser.

[0100] S700, the first connecting electrode 320 located in the transfer hole 210 is connected to the first electrode 120, and the second connecting electrode 321 is connected to the second electrode 121 in the transfer hole 210.

[0101] Specifically, the solder joint 40 on the side of the first connecting electrode 320 away from the substrate 31 is reflow soldered to the first electrode 120 to electrically connect the first connecting electrode 320 and the first electrode 120; and the solder joint 40 on the side of the second connecting electrode 321 away from the substrate 31 is reflow soldered to the second electrode 121 to electrically connect the second connecting electrode 321 and the second electrode 121.

[0102] As is understood, this reflow soldering refers to the process of connecting one or more electronic components to contact pads using solder paste (a mixture of solder and flux), and then melting the solder by controlling the temperature to achieve a permanent bond. Different heating methods such as reflow ovens, infrared heating lamps, or hot air guns can be used for soldering.

[0103] It is understandable that the welding gas generated can be guided to the substrate 11 through the mating hole 211 and the first connecting electrode 320 and the first electrode 120 forming a height difference, so as to avoid the second substrate 30 being damaged by the gas, and also to ensure that the electrodes are insulated from each other when there is too much solder.

[0104] S800, remove the transfer substrate 20 to achieve chip transfer.

[0105] It is worth mentioning that the display panel includes multiple pixel units, each pixel unit includes multiple sub-pixels, and each sub-pixel corresponds to a light-emitting chip 12; for example, each pixel unit includes a red sub-pixel, a green sub-pixel, and a blue sub-pixel; a pixel unit includes a red light-emitting chip 12, a green light-emitting chip 12b12, and a blue light-emitting chip 12c12. See also Figure 8 and Figure 9 As shown, when transferring the light-emitting chips 12, chips of the same color can be transferred first, followed by other colors, and so on, until a large number of full-color LED light-emitting chips 12 are transferred. This sequential transfer method results in a higher success rate and better bonding between the light-emitting chips 12 and the second substrate 30.

[0106] Example 2

[0107] The difference between Embodiment 2 and Embodiment 1 is that a soldering part 40 is provided on the side of the first connecting electrode 320 away from the substrate 31, and one of the second connecting electrode 321 and the second electrode 121 is provided with a protrusion 50 and the other is provided with a groove. The second connecting electrode 321 and the second electrode 121 are connected by the protrusion 50 and the groove. By providing the protrusion 50 and the groove, soldering is not required, that is, reflow soldering is not required, thereby avoiding the problem of poor soldering between the second connecting electrode 321 and the second electrode 121.

[0108] For example, see Figure 10 and Figure 11 As shown, the second connecting electrode 321 has a protrusion 50 on the side away from the substrate 31, and the second electrode 121 has a groove on the layer away from the substrate 11. During the transfer process, the protrusion 50 on the second connecting electrode 321 can be inserted into the groove of the second electrode 121 to realize the connection between the second connecting electrode 321 and the second electrode 121.

[0109] It should be noted that, in order to improve matching accuracy, the protrusion 50 can be a cross-shaped protrusion 50, and the corresponding groove can be designed as a cross-shaped groove.

[0110] Example 3

[0111] Embodiment 3 of this application provides a display panel, which includes a second substrate 30 and multiple sets of light-emitting chips 12. At least a portion of the multiple sets of light-emitting chips 12 are transferred onto the second substrate 30 by the light-emitting chip 12 transfer method in Embodiment 1 or Embodiment 2. For specific details of the light-emitting chip 12 transfer process, please refer to the description of the foregoing embodiments, which will not be repeated here.

[0112] In this embodiment, the light-emitting chips 12 on the second substrate 30 are all transferred by the light-emitting chip 12 transfer method in Embodiment 1 or Embodiment 2, thereby ensuring that the light-emitting chips 12 on the second substrate 30 are all normally emitting light-emitting chips 12, so as to ensure the display effect of the display panel.

[0113] In the description of this specification, references to terms such as "some embodiments," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0114] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application. Therefore, any changes or modifications made in accordance with the claims and description of this application should fall within the scope of this patent application.

Claims

1. A method for transferring light-emitting chips, characterized in that, The method for transferring the light-emitting chip includes: A first substrate is provided, the first substrate including a substrate and a light-emitting chip, the light-emitting chip including a first electrode and a second electrode formed on the substrate and spaced apart from each other, wherein the end face of the first electrode away from the substrate is closer to the substrate than the end face of the second electrode away from the substrate; A transfer substrate is provided, the transfer substrate having a plurality of transfer units, each transfer unit including transfer holes and docking holes that communicate with each other, the docking holes being located at the outer edge of the transfer holes, and the transfer holes corresponding to the light-emitting chip; The first substrate and the transfer substrate are aligned so that the light-emitting chip is placed in the transfer hole; A second substrate is provided, the second substrate including a substrate and a fixing unit disposed on the substrate, the fixing unit including a first connecting electrode and a second connecting electrode disposed at intervals from each other, one end of the first connecting electrode and one end of the second connecting electrode being disposed on the substrate, the end face of the first connecting electrode away from the substrate being further away from the substrate than the end face of the second connecting electrode away from the substrate, a portion of the first connecting electrode corresponding to the first electrode, and the second connecting electrode corresponding to the second electrode; The transfer substrate with the light-emitting chip is aligned with the second substrate so that the first connecting electrode is aligned and inserted with the docking hole, with a part of the first connecting electrode located in the docking hole and the other part located in the transfer hole; After aligning the transfer substrate with the light-emitting chip to the second substrate, the substrate is removed; Connect the first connecting electrode located in the transfer hole to the first electrode, and connect the second connecting electrode to the second electrode in the transfer hole; Remove the transfer substrate.

2. The light-emitting chip transfer method according to claim 1, characterized in that, The transfer hole has docking holes on opposite sides, and the diameter of the docking holes is smaller than the diameter of the transfer hole; the fixing unit includes the second connecting electrode and the first connecting electrodes located on opposite sides of the second connecting electrode, and the two first connecting electrodes are symmetrical with respect to the second connecting electrode.

3. The light-emitting chip transfer method according to claim 1 or 2, characterized in that, The first electrode is arranged around the second electrode.

4. The light-emitting chip transfer method according to claim 3, characterized in that, The first electrode and the second electrode are arranged on the same axis.

5. The light-emitting chip transfer method according to claim 4, characterized in that, The first substrate further includes a first semiconductor layer, a multiple quantum well layer, and a second semiconductor layer stacked sequentially. The first semiconductor layer is disposed on the side of the multiple quantum well layer close to the substrate, the first electrode is disposed on the side of the first semiconductor layer away from the substrate, and the second electrode is disposed on the side of the second semiconductor layer away from the substrate. Wherein, the orthographic projection of the outer edge of the first electrode on the substrate and the orthographic projection of the outer edge of the first semiconductor layer on the substrate are spaced apart; the orthographic projection of the second electrode on the substrate is located within the orthographic projection of the second semiconductor layer on the substrate.

6. The light-emitting chip transfer method according to claim 1, characterized in that, Before aligning the transfer substrate with the transferred light-emitting chip to the second substrate, the light-emitting chip transfer method further includes: At least one of the first connecting electrode and the second connecting electrode is provided with a welding element, the welding element being disposed on the side of the first connecting electrode or the second connecting electrode away from the substrate.

7. The light-emitting chip transfer method according to claim 6, characterized in that, The welding element is provided on the side of both the first connecting electrode and the second connecting electrode away from the substrate.

8. The light-emitting chip transfer method according to claim 6, characterized in that, The first connecting electrode has the welding element on the side away from the substrate. One of the second connecting electrode and the second electrode has a protrusion and the other has a groove. The second connecting electrode and the second electrode are connected by the protrusion and the groove.

9. The light-emitting chip transfer method according to claim 1, characterized in that, The first substrate further includes a transfer layer disposed on the side of the first electrode near the substrate.

10. A display panel, characterized in that, The display panel includes a second substrate and a plurality of light-emitting chips, at least a portion of which are transferred to the second substrate by the light-emitting chip transfer method as described in any one of claims 1-9.

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