Transfer substrate, method for manufacturing the same, and transfer method of light emitting element

Abstract

The application discloses a transfer substrate and a preparation method thereof, and a transfer method of a light-emitting element. The transfer substrate comprises a substrate, the substrate comprising a plurality of first areas; a plurality of dam structures located on one side of the substrate, the dam structures surrounding the first areas to form accommodating grooves, the dam structures comprising at least one flow guide opening in communication with the accommodating grooves; and a plurality of bonding structures located on one side of the substrate, the bonding structures being located in the accommodating grooves and used for fixing the light-emitting element. In the application, the dam structures are used to limit the bonding structures, the bonding structures are formed in the first areas, and the bonding structures are arranged correspondingly to the light-emitting element, so that the transfer process flow is simplified, the cost is saved, the problems of etching residues and uneven etching are avoided, the height of the bonding structures can be controlled, the heights of different bonding structures tend to be consistent, the uniformity of the height of the bonding structures is improved, and the transfer effect of the light-emitting element is improved.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more particularly to a transfer substrate and its preparation method, and a method for transferring light-emitting elements. Background Technology

[0002] With the development of display technology, display products are showing a diversified development trend. Microlight Emitting Diodes (Micro LEDs) are increasingly used in display products due to their advantages such as high brightness, high contrast, and high reliability. The fabrication of Micro LED display panels involves the mass transfer process of Micro LED chips. In existing technologies, before transferring Micro LED chips on a transient substrate, the release adhesive layer between the chips needs to be etched. However, the etching of the release adhesive layer suffers from problems such as incomplete etching and poor etching uniformity, which affects the transfer effect of Micro LED chips. Summary of the Invention

[0003] In view of this, the present invention provides a transfer substrate and its preparation method, as well as a transfer method for light-emitting elements, to simplify the transfer process of light-emitting elements and improve the transfer effect.

[0004] In a first aspect, embodiments of the present invention provide a transfer substrate, comprising:

[0005] A substrate, the substrate comprising a plurality of first regions;

[0006] Multiple dam structures are located on one side of the substrate, the dam structures form a receiving groove around the first region, and the dam structures include at least one flow guiding opening, the flow guiding opening being in communication with the receiving groove;

[0007] Multiple bonding structures are located on one side of the substrate, and the bonding structures are located within the receiving groove. The bonding structures are used to fix the light-emitting element.

[0008] Secondly, embodiments of the present invention provide a method for preparing a transfer substrate, comprising:

[0009] A substrate is provided, the substrate comprising a plurality of first regions;

[0010] A first film layer is prepared on one side of a substrate and the first film layer is patterned to form a plurality of dam structures; the dam structures form a receiving groove around the first region, and the dam structures include at least one flow guiding opening, which communicates with the receiving groove;

[0011] An adhesive structure is prepared within the receiving groove.

[0012] Thirdly, embodiments of the present invention provide a method for transferring a light-emitting element, comprising:

[0013] A transfer substrate is provided in any embodiment of the present invention;

[0014] A growth substrate is provided, wherein the growth substrate includes a plurality of light-emitting elements;

[0015] The light-emitting element on the growth substrate is connected to the bonding structure of the transfer substrate accordingly;

[0016] Peel off the growth substrate;

[0017] The light-emitting element on the transfer substrate is transferred to the driving substrate.

[0018] In this embodiment of the invention, multiple first regions are defined on the substrate. A dam structure is set to form a receiving groove around the first region, and an adhesive structure is formed within the receiving groove. The dam structure can limit the position of the adhesive structure, ensuring that the adhesive structure is formed in the first region. Thus, the adhesive structure and the light-emitting element are correspondingly positioned, eliminating the need for a release adhesive layer etching process, thereby simplifying the light-emitting element transfer process and fundamentally avoiding etching residue and uneven etching problems. Furthermore, it can reduce the amount of release adhesive used, saving costs. In addition, the dam structure has a flow-guiding opening, which allows for control of the height of the adhesive structure, making the heights of different adhesive structures more consistent, improving the overall height uniformity of the adhesive structure, and facilitating the positioning and release of the light-emitting element. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the transfer of a light-emitting element in a related technology;

[0020] Figure 2 This is a schematic diagram of the structure of a transfer substrate provided in an embodiment of the present invention;

[0021] Figure 3 for Figure 2 A schematic diagram of the cross-sectional structure along the A-A' direction;

[0022] Figure 4 for Figure 3 A magnified structural diagram at point B;

[0023] Figure 5 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention;

[0025] Figure 7 for Figure 6 A schematic diagram of the cross-sectional structure along the C-C' direction;

[0026] Figure 8 for Figure 6 A schematic diagram of the cross-sectional structure along the D-D' direction;

[0027] Figure 9 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention;

[0028] Figure 10 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention;

[0029] Figure 11 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention;

[0030] Figure 12 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention;

[0031] Figure 13 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention;

[0032] Figure 14 A flowchart illustrating a method for preparing a transfer substrate according to an embodiment of the present invention;

[0033] Figure 15 for Figure 14 A schematic diagram of the preparation method shown;

[0034] Figure 16 A flowchart of the light-emitting element's light transfer process is provided as an embodiment of the present invention;

[0035] Figure 17 for Figure 16 A schematic diagram of the transfer method shown. Detailed Implementation

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0037] It should be noted that the terms "having," "comprising," and "including" used in this application are all open-ended, meaning that when a module is described as "having," "comprising," or "including" a first element, a second element, and / or a third element, it indicates that the module includes other elements besides the first, second, and / or third elements. Furthermore, the ordinal numbers "first," "second," and "third" used in this application are not intended to define a specific order, but only to distinguish between the various parts. In this application, when describing layer A and layer B as "co-located," it means that layer A and layer B are manufactured using the same materials and processes.

[0038] Figure 1 This is a schematic diagram of a light-emitting element transfer in related technologies, for reference. Figure 1 In related technologies, before the light-emitting element 5' is transferred from the growth substrate to the transient substrate 1', a full-layer release adhesive layer 4' is formed on the transient substrate 1'. The light-emitting element 5' is then transferred to the transient substrate 1', and the light-emitting element 5' is fixed to the transient substrate 1' by the release adhesive layer 4'. Subsequently, the release adhesive layer 4' needs to be etched to remove the release adhesive layer 4' between adjacent light-emitting elements 5' before transferring the light-emitting element 5' to the carrier substrate. However, the inventors have discovered that during the etching of the release adhesive layer 4', incomplete etching may occur, resulting in residual release adhesive layer 4' between adjacent light-emitting elements 5' (as shown in the dotted box in the figure). Additionally, uneven etching and different thicknesses of the release adhesive layer 4' at different light-emitting elements 5' may also occur. With this setup, during the subsequent release of the light-emitting elements 5', some light-emitting elements 5' may fail to release properly, affecting the process progress.

[0039] In view of the deficiencies of the above-mentioned related technologies, the present invention provides a transfer substrate that can be used for mass transfer of Micro LED chips. Figure 2 This is a schematic diagram of a transfer substrate provided in an embodiment of the present invention. Figure 3 for Figure 2 A cross-sectional structural diagram along the A-A' direction can be referenced. Figure 2 and Figure 3 The transfer substrate 100 includes a substrate 1, a plurality of dam structures 2 and a plurality of bonding structures 4. The substrate 1 includes a plurality of first regions 1a. The plurality of dam structures 2 are located on one side of the substrate 1 and form a receiving groove 3 around the first region 1a. The dam structure 2 includes at least one flow guiding opening 20, which communicates with the receiving groove 3. The plurality of bonding structures 4 are located on one side of the substrate 1 and are located in the receiving groove 3. The bonding structures 4 are used to fix the light-emitting element (not shown in the figure).

[0040] The transfer substrate 100 includes a substrate 1. The material of the substrate 1 is not limited, and those skilled in the art can select it according to actual needs. For example, the material of the substrate 1 can be sapphire or quartz, but it is not limited to these. Sapphire and quartz have high strength and light transmittance, which allows more laser beams to pass through the substrate 1 when the light-emitting element on the transfer substrate 100 is subsequently released using a laser, thereby ensuring the normal release of the light-emitting element on the transfer substrate 100. Of course, in other embodiments, if a thermal release process or an electrostatic release process is used to transfer the light-emitting element, the light transmittance of the substrate 1 is not required.

[0041] like Figure 2 and Figure 3 As shown, one side surface of the substrate 1 can be divided into multiple first regions 1a. The first region 1a can be regarded as the light-emitting element receiving region. After the light-emitting element is transferred from the growth substrate to the substrate 1, the light-emitting element is placed in the first region 1a. The distribution of the first regions 1a on the substrate 1 is not limited. For example, the first regions 1a can be arrayed on the substrate 1, but it is not limited to this.

[0042] Continue to refer to Figure 2 and Figure 3 Multiple dam structures 2 are also provided on one side of the substrate 1. Each dam structure 2 corresponds to a first region 1a. The dam structure 2 is a wall-like structure with a certain height (along the thickness direction Z of the substrate 1). The dam structure 2 forms a receiving groove 3 around the first region 1a; in other words, the dam structure 2 forms a side-closed wall-like structure around the first region 1a. Each bonding structure 4 is located in a corresponding receiving groove 3, meaning that the dam structure 2 is located outside the bonding structure 4 along a direction parallel to the plane of the substrate 1. The dam structure 2 serves as a limiting structure, ensuring that the bonding structure 4 is filled within the receiving groove 3. The bonding structure 4 subsequently contacts and fixes the light-emitting element.

[0043] The materials used for the retaining structure and the bonding structure are not limited, but care should be taken to ensure that the two materials do not react chemically. In some embodiments, the retaining structure may be made of photoresist or silicon dioxide, and the bonding structure may be made of release adhesive to fix the light-emitting element. During the transfer of the light-emitting element, the light-emitting element is aligned with the bonding structure and then pressed down to fix the light-emitting element to the bonding structure. Subsequently, the first transfer process of the light-emitting element is completed by separating the light-emitting element and the growth substrate.

[0044] In this embodiment of the invention, by dividing the substrate into sections and setting a dam structure around the first section, an adhesive structure is formed within the dam structure, allowing the adhesive structures to be formed one-to-one in the first section of the substrate. Thus, when releasing the light-emitting element from the transfer substrate, the release adhesive etching process in related technologies is no longer required, thereby simplifying the transfer process and fundamentally avoiding etching residues and uneven etching, ensuring the normal release of the light-emitting element from the transfer substrate.

[0045] Optionally, release adhesive can be injected into the receiving groove (i.e., the first area) through processes such as dispensing or inkjet printing to form an adhesive structure. In this way, compared with the spin coating process used in related technologies to prepare a whole layer of release adhesive, the solution in this invention can save the amount of release adhesive used, thereby saving costs.

[0046] Furthermore, Figure 4 for Figure 3 The enlarged structural diagram at point B can be referenced further. Figures 2-4 It is worth noting that, in this embodiment of the invention, a flow guiding opening 20 is formed on the dam structure 2. The flow guiding opening 20 penetrates the sidewall of the dam structure 2 along a direction parallel to the plane of the substrate 1, thereby connecting the receiving groove 3 with the region outside the dam structure 2. The region outside the dam structure 2 is the region between adjacent dam structures 2, which can be defined as the second region 1b. The flow guiding opening 20 connects the receiving groove 3 and the second region 1b along a direction parallel to the plane of the substrate 1.

[0047] In this configuration, when the release adhesive is injected into the receiving tank 3, it can flow to the outside of the dam structure 2 when it reaches the flow-guiding opening 20. The height of the bonding structure 4 in the receiving tank 3 is close to or the same as the height of the dam structure 2 at the flow-guiding opening 20, thus enabling control over the height of the bonding structure 4. This makes the heights of different bonding structures 4 more consistent, improving the uniformity of the overall height (or thickness) of the bonding structure 4. Good uniformity in the overall thickness of the bonding structure 4 is beneficial for the positioning and release of the light-emitting element.

[0048] It should be noted that when injecting release adhesive into the receiving tank 3, the amount of release adhesive injected can be controlled by optimizing the process to meet the critical value of flowing out from the guide opening 20. In this way, it can be ensured that the thickness of the bonding structure 4 in each receiving tank 3 is consistent, and excessive release adhesive can be avoided from overflowing from the guide opening 20.

[0049] In this embodiment of the invention, the shape and height of the retaining structure 2 are not limited. The orthographic projection shape of the retaining structure 2 on the substrate 1 can be consistent with the orthographic projection shape of the light-emitting element on the substrate 1. The figure shows an example where the orthographic projection shape of the retaining structure 2 on the substrate 1 is rectangular, but this is not the only limitation. In other embodiments not shown, the orthographic projection shape of the retaining structure 2 can be any polygon, such as a circle. It is understood that the retaining structure 2 defines the receiving groove 3, and the bonding structure 4 is located in the receiving groove 3. The orthographic projection shapes of the receiving groove 3 and the bonding structure 4 on the substrate 1 should correspond to the closed shape formed by the orthographic projection shape of the retaining structure 2 on the substrate 1.

[0050] For example, such as Figure 2 As shown, the orthographic projection of the dam structure 2 on the substrate 1 can be set as a polygon, and the flow guiding opening 20 is located on at least one side of the dam structure 2.

[0051] For the polygonal wall-like dam structure 2, the flow guiding opening 20 can be formed on at least one side wall of the dam structure 2, such that the orthographic projection of the flow guiding opening 20 on the substrate 1 is located on at least one side of the projection pattern of the dam structure 2. Figure 2 The illustration shows a flow-guiding opening 20 formed on one side wall of the retaining dam structure 2, but it is not limited to this. In other embodiments, flow-guiding openings 20 may be provided on each side wall of the retaining dam structure 2 to improve the flow-guiding effect.

[0052] Among them, such as Figure 2 As shown, the dimension of the flow-guiding opening 20 in the direction of extension of the side wall of the retaining dam structure 2 can be smaller than the dimension of the side wall of the retaining dam structure 2 in that direction, so as to avoid the flow-guiding opening 20 being too large and causing too much overflow of release adhesive.

[0053] The embodiments of the present invention do not limit the preparation method of the dam structure. Those skilled in the art can set it according to the actual situation. For example, a dam structure with a flow guiding opening can be formed by using patterning processing technology such as photolithography.

[0054] In this embodiment of the invention, multiple first regions are defined on the substrate. A dam structure is set to form a receiving groove around the first region, and an adhesive structure is formed within the receiving groove. The dam structure can limit the position of the adhesive structure, ensuring that the adhesive structure is formed in the first region. Thus, the adhesive structure corresponds to the light-emitting element. When transferring the light-emitting element, the release adhesive etching process in related technologies is no longer required, thereby simplifying the transfer process and fundamentally avoiding etching residue and uneven etching problems. Furthermore, the amount of release adhesive used can be reduced, saving costs. The dam structure has a flow-guiding opening, which allows for control of the height of the adhesive structure, making the heights of different adhesive structures more consistent, improving the overall height uniformity of the adhesive structure, and facilitating the positioning and release of the light-emitting element.

[0055] Optional, you can continue to refer to Figures 2-4 The substrate 1 also includes a second region 1b, which surrounds the first region 1a and, along the thickness direction of the substrate 1, the dam structure 2 does not overlap with the second region 1b; along the thickness direction of the substrate 1, the second region 1b overlaps with the bonding structure 4 in one or more parts.

[0056] In the above embodiments, the second region 1b is simply described as follows: as mentioned above, the second region 1b is the outer region of the dam structure 2, and the orthographic projection of the dam structure 2 on the substrate 1 does not overlap with the second region 1b. In this embodiment, the orthographic projection of the bonding structure 4 on the substrate 1 may be further limited to overlapping the second region 1b at most, that is, the second region 1b of the substrate 1 is kept as bare as possible to avoid adjacent bonding structures 4 overflowing and sticking to the second region 1b.

[0057] When the release adhesive is injected into the receiving tank 3, when the height of the release adhesive reaches the position of the guide opening 20, the release adhesive overflows along the outer wall of the dam structure 2 through the guide opening 20. In this embodiment of the invention, when the overflow edge of the release adhesive flows to the outer wall of the dam structure 2, the injection of the release adhesive can be stopped, thereby controlling the release adhesive to overflow into the second region 1b as little as possible, so that the bonding structure 4 overlaps with the second region 1b in at most parts.

[0058] Optional, you can continue to refer to Figures 2-4 In a possible embodiment, the dam structure 2 includes a first dam portion 21 and a second dam portion 22. The orthographic projections of the first dam portion 21 and the second dam portion 22 on the substrate 1 are both annular. The second dam portion 22 is located on the side of the first dam portion 21 away from the substrate 1. The surface of the side of the first dam portion 21 away from the substrate 1 includes a third region 21a and a fourth region 21b. The fourth region 21b surrounds the third region 21a. The second dam portion 22 is located in the fourth region 21b. The second dam portion 22 includes a flow guiding opening 20.

[0059] like Figures 2-4 As shown, both the first dam portion 21 and the second dam portion 22 are annular wall structures. The first dam portion 21 and the second dam portion 22 can be integrally formed or separately. The filling patterns of the first dam portion 21 and the second dam portion 22 are identical. The first dam portion 21 and the second dam portion 22 together define the receiving groove 3. The first dam portion 21 is close to and in contact with the substrate 1, while the second dam portion 22 is located on the side of the first dam portion 21 facing away from the substrate 1. In the orientation shown in the figure, the second dam portion 22 is formed on top of the first dam portion 21.

[0060] The surface of the first dam portion 21 facing away from the substrate 1 can be defined as the upper surface of the first dam portion 21. For example, Figure 4As shown, in this embodiment, the upper surface of the first dam portion 21 includes a third region 21a and a fourth region 21b surrounding the third region 21a. In other words, the fourth region 21b surrounds the third region 21a and is located outside the third region 21a along a direction parallel to the plane of the substrate 1. Figure 4 A dashed line is shown at the junction of the first dam portion 21 and the second dam portion 22 to indicate the location of the third region 21b. The second dam portion 22 is formed in the fourth region 21b. In the thickness direction Z of the substrate 1, the third region 21a does not overlap with the second dam portion 22. The thickness of the sidewall of the first dam portion 21 (the thickness of the sidewall along the plane parallel to the substrate 1) is greater than the thickness of the sidewall of the second dam portion 22, and the outer surfaces of the sidewalls of the first dam portion 21 and the second dam portion 22 are flush.

[0061] In this configuration, the first dam section 21 at the third zone 21a forms an overlapping step S, on which the light-emitting element can be attached, improving the fixing effect of the light-emitting element. Furthermore, in this embodiment, the flow-guiding opening 20 can extend downwards from the side surface of the second dam section 22 away from the first dam section 21 by a certain height. This can also be understood as a notch in the sidewall of the first dam section 21. Thus, the flow-guiding opening 20 is closer to the side of the dam structure 2 away from the substrate 1, and the fabrication process of the flow-guiding opening 20 is relatively simple. The design of the first dam section 21 and the second dam section 22 improves the design flexibility of the dam structure 2 and facilitates the fixing of the light-emitting element to the bonding structure 4.

[0062] The filling height of the bonding structure 4 within the receiving groove 3, which is also the height of the bonding structure 4 along the thickness direction Z of the substrate 1, is related to the opening height H of the flow guiding opening 20 in that direction. Figure 4 The diagram shows that the opening height H of the flow guide opening 20 is less than the maximum height H4 of the second dam section 22. That is, the flow guide opening 20 is provided with a second dam section 22 of a certain height on the side facing the substrate 1, and the side of the flow guide opening 20 facing the substrate 1 is higher than the top of the first dam section 21. Figure 5 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention. Figure 5 In the embodiment shown, the opening height H of the flow guide opening 20 is the same as the maximum height H4 of the second dam section 22. That is, the second dam section 22 is not provided on the side of the flow guide opening 20 facing the substrate 1, and the side of the flow guide opening 20 facing the substrate 1 is flush with the top of the first dam section 21.

[0063] Optional, Figure 6 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention. Figure 7 for Figure 6A schematic diagram of the cross-sectional structure along the C-C' direction. Figure 6 and Figure 7 The structure of the light-emitting element 5 after it has been transferred to the transfer substrate 100 is shown, and can be seen in conjunction with the reference. Figure 4 , Figure 6 and Figure 7 The receiving groove 3 includes a first groove 31 and a second groove 32 that are connected. A first dam portion 21 surrounds a first region 1a to form the first groove 31, and a second dam portion 22 surrounds a third region 21a to form the second groove 32. The bonding structure 4 fills the first groove 31. The light-emitting element 5 includes a light-emitting body 51 and a connecting electrode group 52. The connecting electrode group 52 is located on one side surface of the light-emitting body 51 and includes at least one connecting electrode 520. After the light-emitting element 5 is transferred to the transfer substrate 100, along the thickness direction Z of the substrate 1, the connecting electrode 520 extends at least partially into the first groove 31 and is connected to the bonding structure 4.

[0064] like Figure 4 , Figure 6 and Figure 7 As shown, the annular wall-shaped first dam portion 21 surrounds the first groove 31 forming the receiving groove 3, and the annular wall-shaped second dam portion 22 surrounds the second groove 32 forming the receiving groove 3. Along the orientation shown in the figure, the second groove 32 is located above the first groove 31, and the bonding structure 4 at least fills the first groove 31. As mentioned above, the thickness of the sidewall of the first dam portion 21 is greater than the thickness of the sidewall of the second dam portion 22, and the radial dimension of the first groove 31 should be smaller than the radial dimension of the second groove 32. The radial dimension of the groove is the width of the groove in the plane of the substrate 1.

[0065] Continue to refer to Figure 4 , Figure 6 and Figure 7 The light-emitting element 5 includes a light-emitting body 51 and a connecting electrode group 52. The light-emitting element 5 body may include a light-emitting layer for emitting light. The connecting electrode group 52 is disposed on one side surface of the light-emitting body 51. The connecting electrode group 52 may include at least one connecting electrode 520. The connecting electrode 520 refers to the electrode on the side of the light-emitting element 5 closer to the transfer substrate 100 after it is transferred to the transfer substrate 100. The figure shows that the connecting electrode group 52 includes two connecting electrodes 520 as an example, but it is not limited to this. After the light-emitting element 5 is transferred from the growth substrate to the transfer substrate of the present invention, the connecting electrode 520 of the light-emitting element 5 extends downward into the first groove 31, and is then fixed to the transfer substrate 100 by the bonding structure 4 in the first groove 31.

[0066] It should be noted that when transferring the light-emitting element 5 from the growth substrate, after the light-emitting element 5 is aligned with the bonding structure 4, the light-emitting element 5 will be pressed down. Under the action of the downward pressure, the bonding structure 4 may deform, causing the connecting electrode 520 of the light-emitting element 5 to extend into or be inserted into the bonding structure 4. This causes the bonding structure 4 to cover at least part of the side surface of the connecting electrode 520 (the side surface of the connecting electrode 520 refers to the side surface of the connecting electrode 520 facing the inner wall of the receiving groove 4 after the light-emitting element 5 is fixed to the bonding structure 4), thereby improving the fixing effect of the light-emitting element 5.

[0067] Continue to refer to Figure 4 , Figure 6 and Figure 7 The connecting electrode assembly 52 has a first width W1 along the first direction X, and the first groove 31 has a second width W2 along the first direction X, where W1 < W2; the first direction X is parallel to the plane of the substrate 1; after the light-emitting element 5 is transferred to the transfer substrate 100, the bonding structure 4 covers the connecting electrode assembly 52 along the thickness direction Z of the substrate 1.

[0068] like Figure 7 As shown, the width of the connecting electrode group 52 along the first direction X refers to the distance between the two opposite sides of the connecting electrodes 520 in the connecting electrode group 520 after the light-emitting element 5 is fixed to the transfer substrate 100. When the connecting electrode group 52 includes two connecting electrodes 520, the first width W1 is the distance between the opposite sides of the two connecting electrodes 520; when the connecting electrode group 52 includes one connecting electrode 520, the first width W1 is the distance between the two opposite sides of that connecting electrode 520.

[0069] The width of the first groove 31 along the first direction X is the distance between the inner walls of the two opposite sides of the first groove 31 along the first direction X. In this embodiment, after the light-emitting element 5 is fixed to the bonding structure 4, along the first direction X (i.e., the arrangement direction of the connecting electrodes 520), the second width W2 of the first groove 31 is greater than or equal to the first width W1 of the connecting electrode group 52 of the light-emitting element 5, ensuring that the first groove 31 can sufficiently accommodate the connecting electrode group 52 along the first direction X. Preferably, in this embodiment, the second width W2 is greater than the first width W1, so that there is a certain space between the connecting electrode 520 and the inner wall of the first groove 31 along the first direction X, avoiding direct contact between the inner wall of the groove and the connecting electrode 520, thus preventing damage to the connecting electrode 520.

[0070] in addition, Figure 8 for Figure 6 A cross-sectional structural diagram along the D-D' direction can be consulted with reference. Figures 6-8After the light-emitting element 5 is transferred to the transfer substrate 100, the connecting electrode 520 has a fifth width W5 along the second direction Y, and the first groove 31 has a sixth width W6 along the second direction Y, where W5 < W6; the second direction Y is parallel to the plane of the substrate 1, and the second direction Y is perpendicular to the first direction X. If the first direction X is the arrangement direction of the connecting electrodes 520 in the connecting electrode group 52, then the second direction Y can be understood as the extension direction of the connecting electrodes 520. Setting the width of the connecting electrode 520 along the second direction Y to be smaller than the width of the first groove 31 along the second direction Y can further ensure that the connecting electrode group 52 can extend into the first groove 31. In the thickness direction Z of the substrate 1, the bonding structure 4 covers the connecting electrode group 52.

[0071] Optional, you can continue to refer to Figure 6 and Figure 7 The light-emitting body 51 includes a first surface 510, and the connecting electrode group 52 is located on the first surface 510. The first surface 510 has a third width W3 along the first direction X, and the second groove 32 has a fourth width W4 along the first direction X, where W2 < W3 < W4. After the light-emitting element 5 is transferred to the transfer substrate 100, the first surface 510 overlaps with the first dam portion 21 along the thickness direction Z of the substrate 1.

[0072] like Figure 6 and Figure 7 As shown, the surface of the light-emitting body 51 facing the transfer substrate 100 is the first surface 510, and the connecting electrode group 52 is disposed on the first surface 510. The width of the second groove 32 along the first direction X is the distance between the inner walls of the two opposite sides of the second groove 32 along the first direction X. In this embodiment, the width of the first surface 510 along the first direction X can be set to be greater than the width of the first groove 31 along the first direction X, and less than the width of the second groove 32 along the first direction X. In this configuration, when the connecting electrode 520 is fixed to the bonding structure 4, at least a portion of the edge of the first surface 510 will extend above the first dam portion 21, that is, at least a portion of the edge of the first surface 510 extends to the third region 21a of the first dam portion 21. Thus, the bonding structure 4 and the second dam portion 22 can be used as positioning marks to ensure the alignment accuracy of the light-emitting element 5 and the bonding structure 4.

[0073] Alternatively, after the light-emitting element 5 is transferred to the transfer substrate 100, the periphery of the first surface 510 overlaps with the third region 21a of the first dam portion 21 along the thickness direction Z of the substrate 1.

[0074] like Figures 6-8As shown, the first surface 510 has a seventh width W7 along the second direction Y, and the second groove 32 has an eighth width W8 along the second direction Y. W6 < W7 < W8 can be further set so that the area of ​​the first surface 510 is larger than the opening area of ​​the first groove 31 and smaller than the opening area of ​​the second groove 32. After the light-emitting element 5 is aligned with the bonding structure 4, along the thickness direction Z of the substrate 1, the periphery of the first surface 510 of the light-emitting body 51 overlaps with the third region 21a (i.e., the overlapping step described above) of the first dam portion 21, and the projection of the second groove 32 covers the projection of the light-emitting element 5.

[0075] Figures 6-8 In the illustrated embodiment, the periphery of the first surface 510 directly overlaps the third region 21a of the first dam section 21. The first surface 510 can close the first groove 31, thereby enclosing the connecting electrode 520 within the first groove 31. This protects the connecting electrode 520, preventing damage from the subsequent roughening process of the light-emitting element 5. The roughening process refers to roughening the light-emitting side surface of the light-emitting body 51 (i.e., the surface opposite to the first surface 510) to form multiple microstructures on the light-emitting side surface, thereby improving the light extraction efficiency of the light-emitting element 5.

[0076] Figure 9 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention, which can be referred to. Figure 9 , Figure 9 In the illustrated embodiment, the periphery of the first surface 510 overlaps with the first dam portion 21 via the adhesive structure 4. The first surface 510 and the adhesive structure 4 seal the first groove 31, ensuring protection for the connecting electrode 520.

[0077] Of course, in other embodiments not shown, the light-emitting element 5 may not be roughened. Along the thickness direction Z of the substrate 1, there may be a certain gap between the first surface 510 and the first dam portion 21, thereby appropriately reducing the contact area between the light-emitting element 5 and the dam structure 2, and avoiding the dam structure 2 from exerting a large force on the light-emitting element 5, which could cause damage to the light-emitting element 5.

[0078] Optional, you can continue to refer to Figure 7 Along the thickness direction Z of the substrate 1, the connecting electrode 520 has a first height H1, and the first dam portion 21 has a second height H2, where H1 < H2; after the light-emitting element 5 is transferred to the transfer substrate 100, the bonding structure 4 covers the connecting electrode 520.

[0079] like Figure 7As shown, in an optional embodiment, the height of the connecting electrode 520 along the thickness direction Z of the substrate 1 can be less than the height of the first dam portion 21 along that direction. The second height H2 of the first dam portion 21 is the height of the first groove 31. The adhesive structure 4 at least fills the first groove 31, that is, the height of the adhesive structure 4 is greater than or equal to the height of the first groove 31, thereby making the height of the adhesive structure 4 greater than or equal to the height of the connecting electrode 520. When the light-emitting element 5 is aligned and pressed down with the adhesive structure 4, the adhesive structure 4 can completely cover the connecting electrode 520, that is, the adhesive structure 4 covers the side of the connecting electrode 520, improving the fixing effect while also protecting the connecting electrode 520. In addition, setting the height of the first dam portion 21 to be greater than the height of the connecting electrode 520 allows for a larger pressing margin for the connecting electrode 520, preventing the side of the connecting electrode 520 away from the first surface 510 from passing through the adhesive structure 4 and contacting the substrate 1 during the pressing process, thereby preventing the hard substrate 1 from damaging the connecting electrode 520 and ensuring that the light-emitting element 5 can emit light normally.

[0080] Optional, you can continue to refer to Figure 7 The second dam section 22 includes a first part 221 and a second part 222 connected end to end along the circumferential direction of the second dam section 22. The flow guide opening 20 is located on the side of the second part 222 away from the first dam section 21. The bonding structure 4 is also located in part of the second groove 32. Along the thickness direction Z of the substrate 1, the bonding structure 4 has a third height H3, and the first part 221 has a fourth height H4, where H2 < H3 < (H2 + H4). After the light-emitting element 5 is transferred to the transfer substrate 100, the bonding structure 4 also covers part of the sidewall of the light-emitting body 51.

[0081] like Figure 7 As shown, the first part 221 and the second part 222 can be an integral structure. The second part 222 refers to the second dam section 22 located below and connected to the flow guide opening 20 along the thickness Z direction of the substrate 1. Both sides of the second part 222 along the circumferential direction of the second dam section 22 and both sides of the flow guide opening 20 along the circumferential direction of the second dam section 22 are the first part 221. The maximum height of the second dam section 22 in the thickness Z direction of the substrate 1 mentioned above is the height H4 of the first part 221. The second part 222 has a fifth height H5. The sum of the opening height of the flow guide opening 20 and the height of the second part 222 is the height H4 of the first part 221, that is, (H+H5)=H4. The sum of the height H2 of the first dam section 21 and the height H4 of the first part 221 is the maximum height of the dam structure 2.

[0082] Continue to refer to Figure 7The bonding structure 4 is also formed within a portion of the second groove 32. In the thickness direction Z of the substrate 1, the height H3 of the bonding structure 4 is greater than the height of the first groove 31 (i.e., the second height H2 of the first dam portion 21) and less than the maximum height (H2+H4) of the dam structure 2. The connecting electrode 520 of the light-emitting element 5 extends into the first groove 31 and is fixed to the bonding structure 4 within the first groove 31. A portion of the light-emitting body 51 of the light-emitting element 5 is located within the second groove 32, and the bonding structure 4 within the second groove 32 covers a portion of the sidewall of the light-emitting body 51. The advantage of this arrangement is that it further ensures the fixing effect between the light-emitting element 5 and the transfer substrate 100, as well as the protective effect of the bonding structure 4 on the connecting electrode 520.

[0083] Further reference Figure 7 Along the thickness direction Z of the substrate 1, the second part 222 has a fifth height H5; 0≤|H3-(H5+H2)|≤ΔH, where ΔH is a preset difference value.

[0084] As analyzed above, due to the presence of the flow-guiding opening 20 and the second part 222, the fifth height H5 of the second part 222 should be greater than 0 and less than the fourth height H4 of the first part 221. In the thickness direction Z of the substrate 1, the sum of the second height H2 of the first dam portion 21 and the fifth height H5 of the second part 222 (H2+H5) is the height of the dam structure 2 at the flow-guiding opening 20, or the height of the receiving groove 3 at the flow-guiding opening 20. When the release adhesive is injected into the receiving groove 3, it will flow into the flow-guiding opening 20 when its height reaches the flow-guiding opening 20. Therefore, ideally, the height of the bonding structure 4 is the same as the height of the dam structure 2 at the flow-guiding opening 20, i.e., H3 = (H5+H2). However, due to limitations in the injection process precision, there may be a slight deviation between the height of the bonding structure 4 and the height of the dam structure 2 at the flow guide opening 20. In this embodiment, the absolute value of the height difference between the two is limited to less than or equal to a preset difference ΔH, thereby ensuring that the height of the bonding structure 4 and the height of the dam structure 2 at the flow guide opening 20 tend to be consistent. The specific value of the preset difference ΔH is related to the actual process precision, and this embodiment does not limit it.

[0085] The above embodiments are all illustrated using the example of a dam structure 2 including a first dam section 21 and a second dam section 22, but are not limited to this. For example, Figure 10 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention. Figure 11 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention, which can be referred to. Figure 10 and Figure 11In another possible embodiment, the dam structure 2 is annular in orthographic projection onto the substrate 1. The dam structure 2 includes a third part 23 and a fourth part 24 connected end to end along the circumferential direction of the dam structure 2. The flow guide opening 20 is located on the side of the fourth part 24 away from the substrate 1. The light-emitting element 5 includes a light-emitting body 51 and a connecting electrode group 52. The connecting electrode group 52 is located on one side surface of the light-emitting body 51 and includes at least one connecting electrode 520. After the light-emitting element 5 is transferred to the transfer substrate 100, the connecting electrode 520 extends at least partially into the receiving groove 3 and is connected to the bonding structure 4 along the thickness direction Z of the substrate 1.

[0086] Figure 10 and Figure 11 In the illustrated embodiment, the sidewall thickness of the dam structure 2 remains constant, and the dam structure 2 as a whole is an annular wall structure with a uniform sidewall thickness. The flow-guiding opening 20 can extend downwards from the side surface of the dam structure 2 away from the substrate 1 to a certain height. Specifically, the third part 23 and the fourth part 24 can be an integral structure. The fourth part 24 refers to the portion of the dam structure 2 located below the flow-guiding opening 20 and connected to the flow-guiding opening 20 along the thickness direction Z of the substrate 1. Both sides of the fourth part 24 along the circumferential direction of the dam structure 2 and both sides of the flow-guiding opening 20 along the circumferential direction of the dam structure 2 are the third part 23. The height of the dam structure 2 at the flow-guiding opening 20 is the height of the fourth part 24. In this configuration, no overlapping steps are formed in the dam structure 2, the structure of the dam structure 2 is simple, and the manufacturing process is relatively simple.

[0087] refer to Figure 10 and Figure 11 Based on this dam structure 2, the shape of the receiving groove 3 is relatively regular. When the release adhesive is injected into the receiving groove 3, it will flow into the guiding opening 20 when it reaches the top of the fourth part 24 (at the guiding opening 20). The height of the final bonding structure 4 is close to or the same as the height of the fourth part 24. In this embodiment, along the thickness direction Z of the substrate 1, the connecting electrode 520 has a first height H1, the bonding structure 4 has a third height H3, the third part 23 has a sixth height H6, and the fourth part 24 has a seventh height H7; H1 < H3 = H7 < H6. The bonding structure 4 may include covering at least part of the connecting electrode 520.

[0088] Figure 10 and Figure 11 The difference in the embodiment shown is the dimensions of the light-emitting element 5 and the receiving groove 3 in the plane direction parallel to the substrate 1. Figure 10In the illustrated embodiment, after the light-emitting element 5 is transferred to the transfer substrate 100, the width of the first surface 510 of the light-emitting body 51 along the first direction X (i.e., the third width W3 shown in the figure) is smaller than the width of the receiving groove 3 along the first direction X (i.e., the fourth width W4 shown in the figure), and the width of the first surface 510 of the light-emitting body 51 along the second direction (not shown in the figure) is smaller than the width of the receiving groove 3 along the second direction, such that the orthographic projection of the receiving groove 3 on the substrate 1 covers the orthographic projection of the light-emitting element 5 on the substrate 1. With this configuration, the light-emitting element 5 can be pressed down until its first surface 510 contacts the bonding structure 4, allowing the bonding structure 4 to completely cover the connecting electrode 520, thus improving the protection of the connecting electrode 520. Figure 11 In the illustrated embodiment, after the light-emitting element 5 is transferred to the transfer substrate 100, the width of the first surface 510 of the light-emitting body 51 along the first direction X (i.e., the third width W3 shown in the figure) is greater than the width of the receiving groove 3 along the first direction X (i.e., the fourth width W4 shown in the figure), and the width of the first surface 510 of the light-emitting body 51 along the second direction (not shown in the figure) is greater than the width of the receiving groove 3 along the second direction; the width of the connecting electrode group 52 of the light-emitting element 5 along the first direction X (i.e., the first width W1 shown in the figure) is less than the width of the receiving groove 3 along the first direction X (i.e., the fourth width W4 shown in the figure), and the width of the connecting electrode group 52 of the light-emitting element 5 along the second direction is less than the width of the receiving groove 3 along the second direction. In this configuration, the orthographic projection of the receiving groove 3 on the substrate 1 covers the orthographic projection of the connecting electrode group 52 on the substrate 1, and the edge of the first surface 510 of the light-emitting body 51 overlaps the third part 23 of the dam structure 2.

[0089] Optional, Figure 12 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention. Figure 13 This is a schematic diagram of another transfer substrate provided in an embodiment of the present invention, which can be referred to in conjunction with reference to... Figure 12 and Figure 13In a possible embodiment, the light-emitting element 5 includes a light-emitting body 51 and a connecting electrode group 52. The connecting electrode group 52 is located on the first surface 510 of the light-emitting body 51 and includes at least one connecting electrode 520. After the light-emitting element 5 is transferred to the transfer substrate 100, the connecting electrode 520 extends at least partially into the receiving groove 3 and is connected to the bonding structure 4. The specific structure of the light-emitting element 5 is the same as in the above embodiment and will not be repeated here. In this embodiment, along the direction perpendicular to the substrate 1 towards the bonding structure 4, at least a portion of the sidewalls of the receiving groove 3 are inclined toward the center of the receiving groove 3, and the overlap area between the bonding structure 4 and the first surface 510 is smaller than the overlap area between the bonding structure 4 and the substrate 1; or, along the direction perpendicular to the substrate 1 of the bonding structure 4, at least a portion of the sidewalls of the receiving groove 3 are inclined toward the center of the receiving groove 3, and the overlap area between the bonding structure 4 and the first surface 510 is larger than the overlap area between the bonding structure 4 and the substrate 1.

[0090] Taking the dam structure 2 as an example, which includes a first dam portion 21 and a second dam portion 22 located on the side of the first dam portion 21 facing away from the substrate 1, Figure 12 In the illustrated embodiment, along the direction perpendicular to the substrate 1 and pointing towards the bonding structure 4, i.e., the thickness direction Z of the substrate 1 shown in the figure, the inner wall of the first dam portion 21 can be inclined towards the center of the first dam portion 21, i.e., the sidewall of the first groove 31 is inclined towards the center of the first groove 31, and the cross-sectional shape of the first groove 31 is a trapezoid. Taking the bonding structure 4 filling only the first groove 31 as an example, the cross-sectional shape of the bonding structure 4 in the first groove 31 is a trapezoid, and the bonding structure 4 in the first groove 31 is defined as the main body of the bonding structure. Along the thickness direction Z of the substrate 1, the overlap area between the main body of the bonding structure and the first surface 510 of the light-emitting body 51 is smaller than the overlap area between the main body of the bonding structure and the substrate 1, i.e., the contact area between the bonding structure 4 and the substrate 1 is larger, and the contact area between the bonding structure 4 and the first surface 510 of the light-emitting element 5 is smaller, which helps to reduce the residue of the bonding structure 4 on the light-emitting element 5 when the light-emitting element 5 is released from the transfer substrate 100. Figure 13 In the illustrated embodiment, along the direction perpendicular to the substrate 1 of the bonding structure 4, which is the opposite direction to the thickness direction Z of the substrate 1 shown in the figure, the inner wall of the first dam portion 21 can be inclined towards the center of the first dam portion 21, that is, the side wall of the first groove 31 is inclined towards the center of the first groove 31, and the cross-sectional shape of the first groove 31 is an inverted trapezoid. The cross-sectional shape of the bonding structure 4 in the first groove 31 is an inverted trapezoid. Along the thickness direction Z of the substrate 1, the overlap area between the bonding structure body and the first surface 510 of the light-emitting body 51 is greater than the overlap area between the bonding structure body and the substrate 1, that is, the contact area between the bonding structure 4 and the substrate 1 is smaller, and the contact area between the bonding structure 4 and the first surface 510 of the light-emitting element 5 is larger. This is beneficial to ensure the fixing strength of the light-emitting element 5 on the transfer substrate 100 and to prevent the light-emitting element 5 from falling off during transfer.

[0091] It should be noted that the current light-emitting element transfer process generally involves two or three transfer steps. The first transfer step involves transferring the light-emitting element from the growth substrate to a first transfer substrate, where the light-emitting elements transferred to the first transfer substrate are of the same color. The second transfer step involves transferring the light-emitting element from the first transfer substrate to a second transfer substrate, where the light-emitting elements transferred to the second transfer substrate are of different colors, thereby achieving the integration and arrangement of light-emitting elements of different colors. The third transfer step is to transfer the light-emitting element from the second transfer substrate to the driving substrate. Currently, the first transfer step mentioned above involves the release adhesive layer etching process in related technologies. Therefore, the transfer substrate in the embodiments of this invention can be the first transfer substrate used in the first transfer step.

[0092] Based on the same concept, embodiments of the present invention also provide a method for preparing a transfer substrate, used to prepare the transfer substrate provided in any embodiment of the present invention. Figure 14 This is a flowchart illustrating a method for fabricating a transfer substrate according to an embodiment of the present invention. Figure 15 for Figure 14 The schematic diagram of the preparation method shown can be referred to. Figure 14 and Figure 15 The method for preparing the transfer substrate includes the following steps:

[0093] S110, Provide a substrate, the substrate including a plurality of first regions.

[0094] like Figure 15 As shown in Figure (a), multiple first regions 1a can be divided in the substrate 1.

[0095] S120. A first film layer is prepared on one side of the substrate and the first film layer is patterned to form a plurality of dam structures; the dam structures form a receiving groove around the first region, and the dam structures include at least one flow guiding opening, which is connected to the receiving groove.

[0096] The material of the first film layer is not limited; for example, it can be a photoresist material or silicon dioxide. Figure 15 As shown in Figure (b), a full-layer first film (not shown in the figure) can be prepared using processes such as spin coating or deposition. The first film is then patterned to remove a portion of the first film in the first region 1a, forming multiple independently arranged dam structures 2 surrounding the first region 1a. The dam structures 2 form receiving grooves 3 around the first region 1a, and each dam structure 2 corresponds one-to-one with the first region 1a. During the patterning process, flow-guiding openings 20 can also be formed on the dam structures 2, connecting the receiving grooves 3 and the area outside the dam structures 2.

[0097] S130. Prepare the bonding structure in the receiving groove.

[0098] like Figure 15 As shown in Figure (c), release adhesive material is injected into the receiving groove 3 to form multiple independently set bonding structures 4, which are used to fix the light-emitting element.

[0099] The above scheme utilizes a dam structure to limit the bonding structure, ensuring its formation in the first region. During the transfer of the light-emitting element, the release adhesive etching process required in related technologies is eliminated, simplifying the transfer process and fundamentally avoiding etching residue and uneven etching. Furthermore, it reduces the amount of release adhesive used, saving costs. Incorporating flow-guiding openings in the dam structure allows for control over the height of the bonding structure, ensuring greater uniformity in the height of different bonding structures and improving the overall height uniformity of the bonding structure. This facilitates the positioning and release of the light-emitting element.

[0100] Optionally, in possible embodiments, the above (S120) can be refined as follows: Step 1, a first sub-film layer is prepared on one side of a substrate; Step 2, a first mask is provided and the first sub-film layer is patterned using the first mask to form a plurality of first dam portions on one side of the substrate; the orthographic projection of the first dam portions on the substrate is annular, and the first dam portions surround a first region; Step 3, a second sub-film layer is prepared on the substrate and the side of the first dam portions facing away from the substrate; Step 4, a second mask is provided and the second sub-film layer is patterned using the second mask to form a second dam portion on the side of the first dam portions facing away from the substrate; the surface of the side of the first dam portion facing away from the substrate includes a third region and a fourth region, the fourth region surrounds the third region, and the second dam portion is located in the fourth region; Step 5, a third mask is provided and the second dam portion is patterned using the third mask to form a flow-guiding opening on the side of the second dam portion facing away from the first dam portion. The above (S130) can be further refined as follows: the bonding structure is prepared in the receiving groove by inkjet printing process.

[0101] As an optional fabrication scheme for the dam structure, the first dam segment and the second dam segment can be fabricated separately. First, a full-length first sub-film layer is fabricated on one side of the substrate. Then, a first mask is used to pattern the first sub-film layer to form multiple first dam segments. The first dam segments surround a first region, and a second region of the substrate is formed between adjacent first dam segments. The surface of the first dam segment facing away from the substrate includes a third region and a fourth region, with the fourth region surrounding the third region. Further, a full-length second sub-film layer is fabricated, covering the exposed substrate and the first dam segments. Then, a second mask is used to pattern the second sub-film layer to fabricate the second dam segment on the side of the first dam segment away from the substrate. The second dam segment is formed in the fourth region of the first dam segment. The second dam segment fabricated in this step is a wall-like structure with completely closed sides. Further, a third mask is used to pattern the second dam segment to remove part of the sidewalls of the second dam segment, forming a flow-guiding opening. The specific structures of the first dam section, the second dam section, and the diversion opening can be referred to in the above embodiments, and will not be repeated here.

[0102] Furthermore, after the dam structure is prepared, release adhesive material can be injected into the receiving tank using inkjet printing. The release adhesive is flowable. When the height of the release adhesive reaches the guide opening, the release adhesive flows into the guide opening. At this point, the injection of release adhesive is stopped and the release adhesive is cured to form an adhesive structure.

[0103] Inkjet printing technology has high precision, which can ensure that the injection height of the released adhesive in different receiving tanks is consistent, thereby improving the uniformity of the height of the bonded structure.

[0104] Based on the same concept, embodiments of the present invention also provide a method for transferring a light-emitting element. Figure 16 This invention provides a flowchart of the light-emitting element's light transfer process according to an embodiment of the invention. Figure 17 for Figure 16 The schematic diagram of the transfer method shown can be referred to. Figure 16 and Figure 17 The method for transferring light-emitting elements includes the following steps:

[0105] S210. Provide a transfer substrate according to any embodiment of the present invention.

[0106] like Figure 17 As shown in Figure (a), the transfer substrate 100 includes a substrate 1, a plurality of dam structures 2 and a plurality of bonding structures 4. The substrate 1 includes a plurality of first regions. The plurality of dam structures 2 are located on one side of the substrate 1. The dam structures 2 surround the first regions to form a receiving groove. The dam structures 2 include at least one flow-guiding opening 20, which communicates with the receiving groove. The plurality of bonding structures 4 are located on one side of the substrate 1 and are located in the receiving groove.

[0107] S220, Provides a growth substrate, on which multiple light-emitting elements are included.

[0108] The growth substrate 200 can be a silicon wafer or a silicon chip, such as... Figure 17 As shown in Figure (b), the growth substrate 200 may include multiple light-emitting elements 5 arranged in an array.

[0109] S230. Connect the light-emitting elements on the growth substrate to the bonding structure of the transfer substrate accordingly.

[0110] like Figure 17 As shown in Figure (c), after aligning the light-emitting element 5 with the bonding structure 4, it is pressed down so that the connecting electrode 520 of the light-emitting element 5 extends into the bonding structure 4.

[0111] S240, peel off the growth substrate.

[0112] like Figure 17 As shown in Figure (d), a laser beam can be used to separate the light-emitting element 5 from the growth substrate 200, thereby transferring the light-emitting element 5 on the growth substrate 200 to the transfer substrate 100.

[0113] S250: Transfer the light-emitting element on the transfer substrate to the driving substrate.

[0114] like Figure 17 As shown in Figure (e) and Figure (f) of 17, this step may include two transfer processes, namely the second transfer process and the third transfer process mentioned above. That is, the light-emitting element 5 on the transfer substrate 100 can be transferred to the carrier substrate 300 (i.e. the second transfer substrate mentioned above) to realize the arrangement of light-emitting elements 5 of different colors, and then the light-emitting element 5 on the carrier substrate 300 can be transferred to the driving substrate 400.

[0115] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A transfer substrate, characterized in that, include: A substrate, the substrate comprising a plurality of first regions; Multiple dam structures are located on one side of the substrate, the dam structures form a receiving groove around the first region, and the dam structures include at least one flow guiding opening, the flow guiding opening being in communication with the receiving groove; Multiple bonding structures are located on one side of the substrate, the bonding structures are located within the receiving groove, and the bonding structures are used to fix the light-emitting element; The dam structure includes a first dam section and a second dam section. The orthographic projections of the first dam section and the second dam section on the substrate are both annular. The second dam section is located on the side of the first dam section away from the substrate. The first dam portion includes a third region and a fourth region on the side surface opposite to the substrate, the fourth region surrounding the third region, and the second dam portion located in the fourth region; The second dam section includes the flow diversion opening.

2. The transfer substrate according to claim 1, characterized in that, The receiving groove includes a first groove and a second groove that are connected. The first dam portion surrounds the first area to form the first groove, and the second dam portion surrounds the third area to form the second groove; the adhesive structure fills the first groove. The light-emitting element includes a light-emitting body and a connecting electrode group, the connecting electrode group being located on one side surface of the light-emitting body, and the connecting electrode group including at least one connecting electrode; After the light-emitting element is transferred to the transfer substrate, the connecting electrode extends at least partially into the first groove and is connected to the bonding structure along the thickness direction of the substrate.

3. The transfer substrate according to claim 2, characterized in that, The connecting electrode group has a first width W1 along the first direction, and the first groove has a second width W2 along the first direction, where W1 < W2. The first direction is parallel to the plane of the substrate. After the light-emitting element is transferred to the transfer substrate, the bonding structure covers the connecting electrode group along the thickness direction of the substrate.

4. The transfer substrate according to claim 3, characterized in that, The light-emitting body includes a first surface, the connecting electrode group is located on the first surface, the first surface has a third width W3 along the first direction, the second groove has a fourth width W4 along the first direction, and W2 < W3 < W4. After the light-emitting element is transferred to the transfer substrate, the first surface overlaps with the first dam section along the thickness direction of the substrate.

5. The transfer substrate according to claim 4, characterized in that, After the light-emitting element is transferred to the transfer substrate, along the thickness direction of the substrate, the perimeter of the first surface overlaps with the third region of the first dam section.

6. The transfer substrate according to claim 2, characterized in that, Along the thickness direction of the substrate, the connecting electrode has a first height H1, and the first dam portion has a second height H2, where H1 < H2; After the light-emitting element is transferred to the transfer substrate, the bonding structure covers the connecting electrode.

7. The transfer substrate according to claim 6, characterized in that, The second dam section includes a first part and a second part that are connected end to end along the circumferential direction of the second dam section, and the flow guide opening is located on the side of the second part away from the first dam section; The bonding structure is also located within a portion of the second groove. Along the thickness direction of the substrate, the bonding structure has a third height H3, and the first portion has a fourth height H4, where H2 < H3 < (H2 + H4). After the light-emitting element is transferred to the transfer substrate, the bonding structure also covers part of the sidewall of the light-emitting body.

8. The transfer substrate according to claim 7, characterized in that, Along the thickness direction of the substrate, the second part has a fifth height H5; 0≤|H3-(H5+H2)|≤ΔH, where ΔH is the preset difference.

9. The transfer substrate according to claim 1, characterized in that, The dam structure has a ring-shaped orthographic projection on the substrate. The dam structure includes a third part and a fourth part that are connected end to end along the circumferential direction of the dam structure. The flow guide opening is located on the side of the fourth part away from the substrate. The light-emitting element includes a light-emitting body and a connecting electrode group, the connecting electrode group being located on one side surface of the light-emitting body, and the connecting electrode group including at least one connecting electrode; After the light-emitting element is transferred to the transfer substrate, the connecting electrode extends at least partially into the receiving groove and is connected to the bonding structure along the thickness direction of the substrate.

10. The transfer substrate according to claim 1, characterized in that, The light-emitting element includes a light-emitting body and a connecting electrode group. The connecting electrode group is located on a first surface of the light-emitting body and includes at least one connecting electrode. After the light-emitting element is transferred to the transfer substrate, the connecting electrode extends at least partially into the receiving groove and is connected to the bonding structure. Along a direction perpendicular to the substrate and pointing towards the bonding structure, at least a portion of the sidewalls of the receiving groove are inclined towards the center of the receiving groove, and the overlap area between the bonding structure and the first surface is smaller than the overlap area between the bonding structure and the substrate; or, Along the direction perpendicular to the substrate along the bonding structure, at least a portion of the sidewalls of the receiving groove are inclined toward the center of the receiving groove, and the overlap area between the bonding structure and the first surface is greater than the overlap area between the bonding structure and the substrate.

11. The transfer substrate according to claim 1, characterized in that, The substrate further includes a second region, which surrounds the first region and extends along the thickness direction of the substrate, wherein the dam structure does not overlap with the second region; Along the thickness direction of the substrate, the second region overlaps with the bonding structure in multiple portions.

12. The transfer substrate according to claim 1, characterized in that, The dam structure has a polygonal orthographic projection on the substrate, and the flow-guiding opening is located on at least one side of the dam structure.

13. A method for preparing a transfer substrate, characterized in that, include: A substrate is provided, the substrate comprising a plurality of first regions; A first film layer is prepared on one side of a substrate and the first film layer is patterned to form a plurality of dam structures; the dam structures form a receiving groove around the first region, and the dam structures include at least one flow guiding opening, which communicates with the receiving groove; A bonding structure is prepared within the receiving groove; A first film layer is prepared on one side of a substrate and patterned to form multiple dam structures, including: A first sub-film layer is prepared on one side of the substrate. A first mask is provided and the first sub-film layer is patterned using the first mask to form a plurality of first dam portions on one side of the substrate; the orthographic projection of the first dam portions on the substrate is annular, and the first dam portions surround the first region; A second sub-film layer is prepared on the side of the substrate and the first dam portion facing away from the substrate. A second mask is provided and the second sub-film layer is patterned on the second mask to form a second dam portion on the side of the first dam portion facing away from the substrate; the surface of the first dam portion facing away from the substrate includes a third region and a fourth region, the fourth region surrounding the third region, and the second dam portion is located in the fourth region; A third mask is provided and the second dam portion is patterned using the third mask to form the flow-guiding opening on the side of the second dam portion opposite to the first dam portion.

14. The method for preparing a transfer substrate according to claim 13, characterized in that, Preparing an adhesive structure within the receiving groove includes: The adhesive structure is prepared in the receiving groove using an inkjet printing process.

15. A method for transferring a light-emitting element, characterized in that, include: Provide a transfer substrate as described in any one of claims 1 to 12; A growth substrate is provided, wherein the growth substrate includes a plurality of light-emitting elements; The light-emitting element on the growth substrate is connected to the bonding structure of the transfer substrate accordingly; Peel off the growth substrate; The light-emitting element on the transfer substrate is transferred to the driving substrate.

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